|
|
%% Papers Published
@article{fds333174,
Author = {Liu, QH},
Title = {Commercial antenna design tools},
Volume = {1},
Pages = {67-109},
Booktitle = {Handbook of Antenna Technologies},
Publisher = {Springer Singapore},
Year = {2016},
Month = {September},
ISBN = {9789814560436},
url = {http://dx.doi.org/10.1007/978-981-4560-44-3_5},
Abstract = {Antenna design traditionally relies on physical
understanding of electromagnetic radiation, intuition, and
experience, as well as trial-and-error experimentations.
With the advent of computers and increasingly sophisticated
numerical methods, however, computer-aided design tools play
a central role in today's antenna design and optimization
process. This chapter presents a summary of commonly used
commercial antenna design simulation tools and their
underlying computational electromagnetics
methods.},
Doi = {10.1007/978-981-4560-44-3_5},
Key = {fds333174}
}
%% Papers Published
@article{fds363047,
Author = {Li, W and Cheng, S and Wang, B and Mao, Z and Zhang, J and Zhang, Y and Liu,
QH},
Title = {The transport of a charged peptide through carbon nanotubes
under an external electric field: a molecular dynamics
simulation.},
Journal = {Rsc Adv.},
Volume = {11},
Number = {38},
Pages = {23589-23596},
Year = {2021},
Month = {July},
url = {http://dx.doi.org/10.1039/d0ra09184g},
Abstract = {The study of interactions between biomolecules and carbon
nanotubes (CNTs) is of great importance in CNT-based drug
delivery systems and biomedical devices. In this work, the
transport of polyarginine (R8) peptide through CNTs under an
external electric field was investigated <i>via</i> all-atom
molecular dynamics (AAMD) simulation. It was found that the
electric field can assist the R8 peptide to overcome the
resistance and make the transport smooth. Moreover, the
efficiency of transport was improved with the increasing
intensity of the electric field in a suitable range. In
addition, we also investigated the effects of different
types of CNTs on the transport of the R8 peptide and found
that the single-walled carbon nanotube (SWCNT) was more
suitable for transporting the R8 peptide than the
double-walled carbon nanotube (DWCNT) due to its lower
energy barrier to the R8 peptide. All these findings shed
light on the role of the electric field on the transport of
the R8 peptide through CNTs and also gave some valuable
insights into the effects of CNT types on the transport
process of the peptide.},
Doi = {10.1039/d0ra09184g},
Key = {fds363047}
}
@article{fds341136,
Author = {Liu, J and Jiang, W and Liu, N and Liu, QH},
Title = {Mixed spectral-element method for the waveguide problem with
bloch periodic boundary conditions},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {61},
Number = {5},
Pages = {1568-1577},
Year = {2019},
Month = {October},
url = {http://dx.doi.org/10.1109/TEMC.2018.2866023},
Abstract = {The mixed spectral-element method (MSEM) is applied to solve
the waveguide problem with the Bloch periodic boundary
condition (BPBC). Based on the BPBC for the original
Helmholtz equation and the periodic boundary condition (PBC)
for the equivalent but modified Helmholtz equation, two
equivalent mixed variational formulations are applied for
the MSEM. Unlike the traditional finite-element method and
spectral-element method (SEM), both these mixed SEM schemes
are completely free of spurious modes because of their use
of the Gauss' law and the curl-conforming vector basis
functions structured by the Gauss-Legendre-Lobatto points. A
simple implementation method is used to deal with the BPBC
and the PBC for the mixed variational formulations so that
both schemes can save computational costs over the
traditional methods. Several numerical results are also
provided to verify that both schemes are free of spurious
modes and have high accuracy with the propagation
constants.},
Doi = {10.1109/TEMC.2018.2866023},
Key = {fds341136}
}
@article{fds340808,
Author = {Zhang, R and Sun, Q and Zhuang, M and Huang, WF and Zhan, Q and Wang, D and Liu, QH},
Title = {Optimization of the Periodic PML for SEM},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {61},
Number = {5},
Pages = {1578-1585},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2019},
Month = {October},
url = {http://dx.doi.org/10.1109/TEMC.2018.2866441},
Abstract = {A periodic perfectly matched layer (PML) is proposed for the
spectral element method (SEM) for the first time, which not
only simplifies the recognition process of a PML domain, but
also saves degrees of freedom (DoFs) when squeezing its
layer number to 1. An objective function to evaluate and
optimize its performance has been theoretically derived. In
the use of this objective function, the PML parameters are
optimized under different conditions; the relationships
between the PML's performance and the scaling factor
profile, the source position, the basis functions' order,
and the PML layer number are studied, which can help guide
the practical applications of PML in the SEM modeling. An
estimation method is also introduced to facilitate the
selection of the scaling factor.},
Doi = {10.1109/TEMC.2018.2866441},
Key = {fds340808}
}
@article{fds342799,
Author = {Chen, Y and Zhu, J and Xie, Y and Feng, N and Liu, QH},
Title = {Smart inverse design of graphene-based photonic
metamaterials by an adaptive artificial neural
network.},
Journal = {Nanoscale},
Volume = {11},
Number = {19},
Pages = {9749-9755},
Year = {2019},
Month = {May},
url = {http://dx.doi.org/10.1039/c9nr01315f},
Abstract = {The burgeoning research of graphene and other 2D materials
enables many unprecedented metamaterials and metadevices for
applications on nanophotonics. The design of on-demand
graphene-based metamaterials often calls for the solution of
a complex inverse problem within a small sampling space,
which highly depends on the rich experiences from
researchers of nanophotonics. Conventional optimization
algorithms could be used for this inverse design, but they
converge to local optimal solutions and take significant
computational costs with increased nanostructure parameters.
Here, we establish a deep learning method based on an
adaptive batch-normalized neural network, aiming to
implement smart and rapid inverse design for graphene-based
metamaterials with on-demand optical responses. This method
allows a quick converging speed with high precision and low
computational consumption. As typical complex
proof-of-concept examples, the optical metamaterials
consisting of graphene/dielectric alternating multilayers
are chosen to demonstrate the validity of our design
paradigm. Our method demonstrates a high prediction accuracy
of over 95% after very few training epochs. A universal
programming package is developed to achieve the design goals
of graphene-based metamaterials with low absorption and near
unity absorption, respectively. Our work may find important
design applications in the field of nanoscale photonics
based on graphene and other 2D materials.},
Doi = {10.1039/c9nr01315f},
Key = {fds342799}
}
@article{fds341168,
Author = {Lan, T and Liu, N and Han, F and Liu, QH},
Title = {Joint Petrophysical and Structural Inversion of
Electromagnetic and Seismic Data Based on Volume Integral
Equation Method},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {57},
Number = {4},
Pages = {2075-2086},
Year = {2019},
Month = {April},
url = {http://dx.doi.org/10.1109/TGRS.2018.2871075},
Abstract = {A joint petrophysical and structural inversion method for
electromagnetic (EM) and seismic data based on the volume
integral equation (VIE) is proposed in this paper. In the
forward EM problem, only the contrast of conductivity is
solved by the electric field integral equation method.
However, in the forward seismic problem, both the contrasts
of velocity and mass density are solved by the combined
field VIE method. Both forward solvers are accelerated by
the fast Fourier transform. In the inversion problem, by
using the petrophysical equations about the porosity and
saturation and applying the chain rule, we fuse the EM and
seismic data and construct the joint petrophysical inversion
equations, which can be solved by the variational Born
iteration method. Then, in order to further enhance the
reconstructed results of the joint petrophysical inversion,
we enforce the structural similarity constraint between
porosity and water saturation and add the cross-gradient
function to the joint petrophysical inversion cost function.
Two typical geophysical models based on the remote sensing
measurement are used to validate the proposed methods. One
is the cross-well model, and the other is the marine surface
exploration model. The advantage of the joint inversion
compared with the separate inversion is evaluated based on
the resolution and the data misfits of the reconstructed
profiles as well as the antinoise ability.},
Doi = {10.1109/TGRS.2018.2871075},
Key = {fds341168}
}
@article{fds340809,
Author = {Zhuang, M and Zhan, Q and Zhou, J and Liu, N and Liu,
QH},
Title = {Incorporating Full Attenuation Mechanisms of Poroelastic
Media for Realistic Subsurface Sensing},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {57},
Number = {4},
Pages = {2087-2096},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2019},
Month = {April},
url = {http://dx.doi.org/10.1109/TGRS.2018.2871375},
Abstract = {Porous materials are ubiquitous in the subsurface formations
of the earth where acoustic and seismic waves are used for
remote sensing. However, it is not well understood how the
dissipation and the dispersion of poroelastic waves are
caused by the viscoelastic and viscous properties of the
constituents such as solid grains and pore fluid and by the
viscoelastic dissipation of the solid frame, as well as the
viscodynamic coupling of the pore fluid to the solid frame
due to its global and local flows relative to the solid
grains. Such attenuation mechanisms have seldom been
incorporated in subsurface sensing simulations, although
they can be very important to applications. In this paper,
we propose a complete attenuation model, including both full
stiffness and viscodynamic dissipation, for poroelastic
media in seismic wave simulations. Completely based on a
generalized Zener model, the effects associated with
physical dissipation and frequency-dependent dispersion are
accurately simulated by a finite-difference time-domain
algorithm. Verifications with analytical solutions show the
accuracy, efficiency, and flexibility of our method.
Numerical results demonstrate that the attenuation of Biot's
model in the sediment of the seafloor has significant
effects on acoustic wave scattering from complex geologic
structures.},
Doi = {10.1109/TGRS.2018.2871375},
Key = {fds340809}
}
@article{fds340797,
Author = {Liu, H and Xia, H and Zhuang, M and Long, Z and Liu, C and Cui, J and Xu, B and Hu, Q and Liu, QH},
Title = {Reverse time migration of acoustic waves for imaging based
defects detection for concrete and CFST structures},
Journal = {Mechanical Systems and Signal Processing},
Volume = {117},
Pages = {210-220},
Publisher = {Elsevier BV},
Year = {2019},
Month = {February},
url = {http://dx.doi.org/10.1016/j.ymssp.2018.07.011},
Abstract = {Ultrasonic non-destructive testing (NDT) technology has been
widely used for defect inspection of concrete structures in
civil engineering. However, most of the current data
processing methods can only provide qualitative information
regarding the existence of concrete inner defects. In this
study, an ultrasonic inner defects inspection approach with
a high-resolution imaging method which combines travel time
tomography (TTT) and reverse time migration (RTM) is
proposed for concrete and concrete-filled steel tube (CFST)
columns. TTT estimates a reasonable distribution of
ultrasonic velocity over the cross-section of the concrete
and CFST columns from the first arrival time of the
ultrasonic transmission signal. The velocity distribution is
used as an input of the initial model for RTM to image the
defects inside the concrete and CFST column cross-sections
with a high resolution. Numerical experiments demonstrate
that the air cavity inside the concrete and CFST columns,
and the debonding between the concrete core and the steel
tube of the CFST column can be identified clearly, and that
the location, size and shape of both defects can be
determined accurately. It is concluded that the proposed
defect detection approach with a high-resolution imaging
method is efficient for the non-destructive inspection of
concrete and CFST structures using ultrasonic
waves.},
Doi = {10.1016/j.ymssp.2018.07.011},
Key = {fds340797}
}
@article{fds363254,
Author = {Wang, B and Zhang, J and Zhang, Y and Mao, Z and Lu, N and Liu,
QH},
Title = {The penetration of a charged peptide across a membrane under
an external electric field: a coarse-grained molecular
dynamics simulation.},
Journal = {Rsc Adv.},
Volume = {8},
Number = {72},
Pages = {41517-41525},
Year = {2018},
Month = {December},
url = {http://dx.doi.org/10.1039/c8ra07654e},
Abstract = {The processes of single polyarginine (R8) peptide
penetration through planar and vesicle membranes under an
external electric field are simulated <i>via</i> a
coarse-grained molecular dynamics (CGMD) simulation. The
results show that the external electric field can greatly
enhance the penetration possibility of the R8 peptide
through membranes. For different membranes (planar membrane
and curved vesicle membrane), the amplitudes of electric
fields needed for penetration are different. The penetration
time of the R8 peptide across membranes decreases with the
increasing amplitude of the external electric field applied.
Under a constant electric field, the length of penetration
time for different membranes is also different. For a better
understanding of the mechanism of the penetration, we
analyzed the Potential Mean Force (PMF) of the R8-membrane
systems and found that the PMFs of the planar membrane and
the curved vesicle membrane have a large difference. This
may be one of the main factors that induces the different
penetration processes of the R8 peptide across membranes
when they respond to the same external electric field. All
these findings shed light on the role of external electric
field on the penetration of R8 peptide through membranes and
also give some insights into the effects of membrane
curvature on the transportation processes of the peptide
carriers.},
Doi = {10.1039/c8ra07654e},
Key = {fds363254}
}
@article{fds341130,
Author = {Hong, D and Yang, S and Zhang, Y and Huang, WF and Liu,
QH},
Title = {Pseudoanalytical formulations for modeling the effect of an
insulating layer in electromagnetic well
logging},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {12},
Pages = {7022-7029},
Year = {2018},
Month = {December},
url = {http://dx.doi.org/10.1109/TGRS.2018.2847027},
Abstract = {In this paper, we present a set of compact formulations to
model the response of the electromagnetic well-logging tools
in eccentric multilayered medium. Different from previous
models, the coil antennas are imbedded in an insulating
protection layer (IPL) rather than expose to the borehole
directly, which agrees much better with some real tools,
e.g., the array induction logging tool. The effects of both
metal mandrel and an IPL are considered in eccentric
scenarios. Our formulations are derived on the basis of the
ratios of cylindrical functions, which obviate the notorious
overflow issues during numerical computation. Numerical
results show that the effect of IPL gradually appears with
the increase of the eccentric distance.},
Doi = {10.1109/TGRS.2018.2847027},
Key = {fds341130}
}
@article{fds341131,
Author = {Ding, X and Zhao, Z and Yang, Y and Nie, Z and Liu, QH},
Title = {A Compact Unidirectional Ultra-Wideband Circularly Polarized
Antenna Based on Crossed Tapered Slot Radiation
Elements},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {66},
Number = {12},
Pages = {7353-7358},
Year = {2018},
Month = {December},
url = {http://dx.doi.org/10.1109/TAP.2018.2867059},
Abstract = {In this communication, a novel compact and unidirectional
circularly polarized antenna based on the crossed printed
tapered slot radiation elements is proposed with the
ultra-wideband operation. The antenna consists of two
crossed tapered slot radiation elements, a compact dual-feed
network, and a dial-shaped parasitic metallic strip. The
tapered slot element is applied and investigated for
wideband coverage within a compact size. By using the
proposed parasitic patches, an additional resonant point is
formed to improve the operation bandwidth for the low band.
To enhance the directivity in the low band, a dial-shaped
parasitic metallic strip is loaded on the top substrate.
With the proposed structure, a compact volume of 0.33\lambda
\times 0.33\lambda \times 0.3\lambda is obtained, where
\lambda is the free-space wavelength at the lowest frequency
of 1.85 GHz. A prototype is fabricated and measured for
validation. The overlapping bandwidth of the 10 dB impedance
bandwidth and the 3 dB axial ratio bandwidth is 105.8%
(1.85-6 GHz).},
Doi = {10.1109/TAP.2018.2867059},
Key = {fds341131}
}
@article{fds340798,
Author = {Chen, H and Du, Y and Yuan, M and Liu, QH},
Title = {Analysis of the Grounding for the Substation under Very Fast
Transient Using Improved Lossy Thin-Wire Model for
FDTD},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {60},
Number = {6},
Pages = {1833-1841},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {December},
url = {http://dx.doi.org/10.1109/TEMC.2018.2807123},
Abstract = {A thin-wire model of conductors with arbitrary cross
sections for a finite-difference time-domain (FDTD) method
is proposed for the study of lightning transients in
electrical systems. The proposed thin-wire model considers
both the frequency-dependent characteristics of the wires
and the influences of the surrounding media. The model
represents a wire using four FDTD cells with an equivalent
side length and modified material parameters. A rational
equivalent circuit is added at the center edge of the FDTD
cells to represent the internal impedance of the wire. An
analytical formula for determining the equivalent side
length and the modified material parameters of the FDTD
cells are also presented. The proposed formula gives a new
prospect to build the thin-wire model in FDTD. In this
model, the equivalent side length can be set arbitrarily and
much larger than the original wire, which can greatly reduce
the computation time. Meanwhile, the method can be extended
to the thin-wire structure with arbitrary cross sections.
The model is verified with various measurements. Finally, a
practical grounding grid of a substation with external water
supply is analyzed.},
Doi = {10.1109/TEMC.2018.2807123},
Key = {fds340798}
}
@article{fds341133,
Author = {Li, XS and Cheng, LL and Liu, XY and Liu, QH},
Title = {Wideband GNSS antenna covered by a double-sided
metasurface},
Journal = {Aeu International Journal of Electronics and
Communications},
Volume = {96},
Pages = {170-177},
Year = {2018},
Month = {November},
url = {http://dx.doi.org/10.1016/j.aeue.2018.09.032},
Abstract = {A novel global navigation satellite system (GNSS) antenna
that employs a double-sided metasurface (MS) to cover a
circularly slotted patch antenna is presented. With this MS,
the antenna has a wide −10-dB reflection coefficient
bandwidth from 1.160 GHz to 1.640 GHz (34.3%) and 3-dB axial
ratio (AR) bandwidth from 1.170 GHz to 1.720 GHz (38.1%),
covering all frequency bands of the GNSSs within a single
band. Meanwhile, the right-handed circular polarization
(RHCP) gain of the antenna is enhanced by the MS, with a
peak value of 6.44 dBic at 1.600 GHz. An electrically small
footprint of 0.364 λ0 × 0.364 λ0 is also achieved by the
antenna at the operating frequency of 1.170
GHz.},
Doi = {10.1016/j.aeue.2018.09.032},
Key = {fds341133}
}
@article{fds341134,
Author = {Xu, KD and Luo, Z and Liu, Y and Liu, QH},
Title = {High-selectivity single-ended and balanced bandpass filters
using ring resonators and coupled lines loaded with multiple
stubs},
Journal = {Aeu International Journal of Electronics and
Communications},
Volume = {96},
Pages = {193-198},
Year = {2018},
Month = {November},
url = {http://dx.doi.org/10.1016/j.aeue.2018.09.021},
Abstract = {High-selectivity single-ended and balanced bandpass filters
(BPFs) using dual-mode ring resonators and coupled lines
loaded with multiple stubs are proposed in this paper. With
the help of the loaded short-circuited and open-circuited
stubs, six deep transmission zeros (TZs) from 0 to 2f0 (f0:
center frequency of the passband) can be realized in both of
single-ended and balanced BPFs to improve the stopband
suppressions. The functions of the loaded short/open stubs
and calculated analysis of TZs’ positions have been
presented. For further demonstration, two examples of
single-ended BPF and balanced BPF with high common-mode
suppression are designed and fabricated, whose center
frequencies are both at 2.1 GHz. Their measured 3-dB
fractional bandwidths are 23.7% and 24.7%
(differential-mode), respectively. The simulated results and
measurements of these two filters are in good
agreement.},
Doi = {10.1016/j.aeue.2018.09.021},
Key = {fds341134}
}
@article{fds341132,
Author = {Liu, Y and Cheng, J and Xu, KD and Yang, S and Liu, QH and Guo,
YJ},
Title = {Reducing the number of elements in the synthesis of a
broadband linear array with multiple simultaneous
frequency-invariant beam patterns},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {66},
Number = {11},
Pages = {5838-5848},
Year = {2018},
Month = {November},
url = {http://dx.doi.org/10.1109/TAP.2018.2862361},
Abstract = {The problem of reducing the number of elements in a
broadband linear array with multiple simultaneous crossover
frequency-invariant (FI) patterns is considered. Different
from the single FI pattern array case, every element channel
in the multiple FI pattern array is divided and followed by
multiple finite-impulse-response (FIR) filters, and each of
the multiple FIR filters has a set of coefficients. In this
situation, a collective filter coefficient vector and its
energy bound are introduced for each element, and then the
problem of reducing the number of elements is transformed as
minimizing the number of active collective filter
coefficient vectors. In addition, the radiation
characteristics including beam pointing direction, mainlobe
FI property, sidelobe level, and space-frequency notching
requirement for each of the multiple patterns can be
formulated as multiple convex constraints. The whole
synthesis method is implemented by performing an iterative
second-order cone programming (SOCP). This method can be
considered as a significant extension of the original SOCP
for synthesizing broadband sparse array with single FI
pattern. Numerical synthesis results show that the proposed
method by synthesizing multiple discretized crossover FI
patterns can save more elements than the original iterative
SOCP by using a single continuously scannable FI pattern for
covering the same space range. Moreover, even for multiple
FI-patterns case with complicated space-frequency notching,
the proposed method is still effective in the reduction of
the number of elements.},
Doi = {10.1109/TAP.2018.2862361},
Key = {fds341132}
}
@article{fds340737,
Author = {Ren, Y and Zhao, SW and Chen, Y and Hong, D and Liu,
QH},
Title = {Simulation of low-frequency scattering from penetrable
objects in layered medium by current and charge integral
equations},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {11},
Pages = {6537-6546},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {November},
url = {http://dx.doi.org/10.1109/TGRS.2018.2840145},
Abstract = {This paper presents a novel accurate and stable current and
charge integral equation (CCIE) solver for the low-frequency
scattering of penetrable objects in layered medium (LM). To
the best of our knowledge, this is the first time to extend
CCIE into LM simulations at low frequency. In order to
integrate the matrix-friendly LM Green's functions (LMGFs)
into CCIE, we have rederived them to define new
quasi-vector/scalar potentials, which are able to annihilate
the frequency singularity in the original LMGFs. Moreover,
an effective preconditioner is adopted to improve the
conditioning of impedance matrices. In comparison with other
perconditioners, this method performs much better. The
excellent performance of this new CCIE solver is then
demonstrated by numerical experiments.},
Doi = {10.1109/TGRS.2018.2840145},
Key = {fds340737}
}
@article{fds340799,
Author = {Xi, D and Jiang, C and Zhou, R and Fang, Z and Zhang, X and Liu, Y and Luan,
B and Feng, Z and Chen, G and Chen, Z and Liu, Q and Yang,
S-Z},
Title = {The universality of lignocellulosic biomass liquefaction by
plasma electrolysis under acidic conditions.},
Journal = {Bioresource Technology},
Volume = {268},
Pages = {531-538},
Year = {2018},
Month = {November},
url = {http://dx.doi.org/10.1016/j.biortech.2018.08.025},
Abstract = {In this research, we compared the discharge characteristics
and catalytic efficiency of sulfuric acid, p-toluenesulfonic
acid, and their respective sodium salts (sodium sulfate and
sodium p-toluenesulfonate) in sawdust liquefaction and found
that sulfuric acid was the optimal catalyst when glycerol
was used as solvent during the plasma electrolytic
liquefaction (PEL) process. When sodium p-toluenesulfonate
was used as the only catalyst, the liquefaction yield
reached 83.51% after 25 min. This yield was higher than
that obtained using sodium sulfate as the catalyst (60.63%)
because different concentrations of H ions were produced in
PEL. Cellulose, lignin, and holocellulose were extracted
from sawdust and successfully liquefied in PEL, illustrating
the universality of PEL. The optical emission spectra of the
different biomass during the PEL process were similar,
indicating that the kinds of free radicals produced were
similar, which can accelerate the liquefaction of
sawdust.},
Doi = {10.1016/j.biortech.2018.08.025},
Key = {fds340799}
}
@article{fds340800,
Author = {Ye, L and Zhang, W and Ofori-Okai, BK and Li, W and Zhuo, J and Cai, G and Liu, QH},
Title = {Super Subwavelength Guiding and Rejecting of Terahertz Spoof
SPPs Enabled by Planar Plasmonic Waveguides and Notch
Filters Based on Spiral-Shaped Units},
Journal = {Journal of Lightwave Technology},
Volume = {36},
Number = {20},
Pages = {4988-4994},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.1109/JLT.2018.2868129},
Abstract = {We numerically simulate novel planar plasmonic waveguides
and notch filters with excellent guiding and rejection of
terahertz (THz) waves with super subwavelength confinement.
Our design is based on spoof surface plasmon polaritons -
surface plasmon polaritons with a frequency that has been
tuned using patterned conductive surfaces. We find that by
using patterns of periodically arranged spiral-shaped units,
the dispersion characteristics can be engineered at will by
tuning the parameters of the spirals. We find that the
resulting plasmonic waveguides have much lower asymptotic
frequencies and much tighter terahertz field confinement
when compared with conventional rectangular-grooved
plasmonic waveguides. We show it is possible to design a
structure with lateral dimensions that are only 25% the size
of the conventional spoof surface plasmon polariton
waveguides but with the same asymptotic frequency. Finally,
we combined this architecture with broadband couplers to
design an ultrawideband low-pass filter with sharp roll-off
(cut-off frequency at 1.29 THz) and low insertion loss (<3
dB). Furthermore, by introducing double ring resonators
based on spiral-shaped units, a planar plasmonic notch
filter with rejection of more than 17 dB between 0.97 and
0.99 THz is demonstrated. The proposed waveguides and notch
filters may have great potential applications in the
promising terahertz integrated plasmonic circuits and
systems.},
Doi = {10.1109/JLT.2018.2868129},
Key = {fds340800}
}
@article{fds339272,
Author = {Ye, L and Zeng, F and Zhang, Y and Xu, X and Yang, X and Liu,
QH},
Title = {Frequency-Reconfigurable Wide-Angle Terahertz Absorbers
Using Single- and Double-Layer Decussate Graphene Ribbon
Arrays.},
Journal = {Nanomaterials (Basel, Switzerland)},
Volume = {8},
Number = {10},
Pages = {E834},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.3390/nano8100834},
Abstract = {We propose and numerically demonstrate two novel terahertz
absorbers made up of periodic single- and double-layer
decussate graphene ribbon arrays. The simulated results show
that the proposed absorbers have narrowband near-unity
terahertz absorption with ultra-wide frequency
reconfiguration and angular stability. By tuning the Fermi
level of graphene ribbons, the over 90% absorbance peak
frequency of the absorber with single-layer graphene
structure can be flexibly adjusted from 6.85 to 9.85 THz for
both the transverse magnetic (TM) and transverse electric
(TE) polarizations. This absorber with single-layer graphene
demonstrates excellent angular stability with the absorbance
peaks of the reconfigurable absorption bands remaining over
99.8% in a wide angle of incidence ranging from 0 to 70°.
The tuning frequency can be significantly enhanced by using
the absorber with double-layer graphene structure from 5.50
to 11.28 THz and 5.62 to 10.65 THz, approaching two octaves
under TM and TE polarizations, respectively. The absorbance
peaks of the reconfigurable absorption band of this absorber
for both polarizations maintain over 70%, even at a large
angle of incidence up to 70°. Furthermore, an analytical
fitting model is also proposed to accurately predict the
absorbance peak frequencies for this variety of absorbers.
Benefitting from these attractive properties, the proposed
absorber may have great potential applications in tunable
terahertz trapping, detecting, sensing, and various
terahertz optoelectronic devices.},
Doi = {10.3390/nano8100834},
Key = {fds339272}
}
@article{fds340848,
Author = {Song, ZY and Chu, QQ and Shen, XP and Liu, QH},
Title = {Wideband high-efficient linear polarization
rotators},
Journal = {Frontiers of Physics},
Volume = {13},
Number = {5},
Publisher = {Springer Nature},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.1007/s11467-018-0779-x},
Abstract = {We demonstrate a wideband polarization rotator with
characteristics of high efficiency and large-range incidence
angle by using a very simple anisotropic reflective
metasurface. The calculated results show that reflection
coefficient of cross polarization is larger than 71% over an
octave frequency bandwidth from ~4.9 GHz to ~10.4 GHz. The
proposed metasurface can still work very well even at
incidence angle of 60°. The experiment at microwave
frequencies is carried out and its results agree well with
the simulated ones.},
Doi = {10.1007/s11467-018-0779-x},
Key = {fds340848}
}
@article{fds341135,
Author = {Chen, H and Du, Y and Yuan, M and Liu, QH},
Title = {Lightning-induced voltages on a distribution line with surge
arresters using a hybrid FDTD-SPICE method},
Journal = {Ieee Transactions on Power Delivery},
Volume = {33},
Number = {5},
Pages = {2354-2361},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.1109/TPWRD.2017.2788046},
Abstract = {Installing lightning arresters is an effective way to
protect distribution lines from lightning-induced voltages.
Spacing effectiveness of lightning arresters is one of the
main concerns in the industry. Different separation
distances of arresters have been proposed in the literature.
In these studies, the simulations are made with simplified
circuit models, which are not sufficient to support their
conclusions. This paper presents a hybrid finite-difference
time-domain (FDTD) SPICE method for analyzing
lightning-induced overvoltages on a distribution line with
arresters being installed. The FDTD method gives a full-wave
solution of the induced voltages. To handle nonlinear
lightning arresters, this FDTD method is integrated with a
circuit solver SPICE. A diode-based model for the arrester
is proposed using a SPICE subcircuit and is coupled to the
FDTD domain as a connecting port. For the verification
purpose, the method is compared with the results obtained in
the rocket-triggered lightning experiment, in which no
arresters were installed. Lightning-induced overvoltages on
the distribution line with different arrester spacing
arrangements are analyzed finally. Efficient arrester
spacing under both first and subsequent strokes is
investigated.},
Doi = {10.1109/TPWRD.2017.2788046},
Key = {fds341135}
}
@article{fds341062,
Author = {Zhan, Q and Zhuang, M and Liu, QH},
Title = {A Compact Upwind Flux with More Physical Insight for Wave
Propagation in 3-D Poroelastic Media},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {10},
Pages = {5794-5801},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.1109/TGRS.2018.2825461},
Abstract = {A high-order discontinuous Galerkin (DG) method with
nonconformal meshes is developed to accurately simulate
large-scale poroelastic wave propagation in 3-D isotropic
media. An exact upwind flux is succinctly derived to serve
as an accurate coupling solver for the DG algorithm.
Specifically, the eigenvalue problem in the Riemann solution
is effectively reduced from the rank of 13 to 4.
Furthermore, this new numerical flux gives more explicit
physical insight, which indicates three-type waves in
poroelastic media: two P waves and one S wave. Validations
and verifications with analytical/semianalytical numerical
solutions demonstrate the accuracy, robustness, and
flexibility of the proposed solver.},
Doi = {10.1109/TGRS.2018.2825461},
Key = {fds341062}
}
@article{fds339684,
Author = {Li, Z and Su, Y and Tang, X and Li, H and Liu, QH},
Title = {A hybrid method to simulate elastic wave scattering of
three-dimensional objects.},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {144},
Number = {4},
Pages = {EL268},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.1121/1.5059332},
Abstract = {A hybrid method based on the finite-difference method and
equivalence principle to simulate elastic wave scattering of
three-dimensional objects is proposed. In this method, the
near fields are first calculated in a rectangular volume
containing the object by the finite-difference method. Then
the displacements and tractions on a virtual surface are
transformed to the far field by the application of the
equivalence principle in elastodynamics. The feasibility is
verified by comparing modeling results with the analytical
solution for the canonical point force source radiation
problem. Modeling for complex scatterer structures shows the
advantage of this method in handling multi-scale scattering
problems.},
Doi = {10.1121/1.5059332},
Key = {fds339684}
}
@article{fds340876,
Author = {Hu, Y and Fang, Y and Wang, D and Zhong, Y and Liu, QH},
Title = {Electromagnetic Waves in Multilayered Generalized
Anisotropic Media},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {10},
Pages = {5758-5766},
Year = {2018},
Month = {October},
url = {http://dx.doi.org/10.1109/TGRS.2018.2825430},
Abstract = {This paper presents the formulations for calculating the
electromagnetic (EM) fields in multilayered generalized
anisotropic media. Maxwell's equations are written into a
first-order differential (in z) equation concerning the
transverse electric and magnetic field components in the
spectral domain. The equation can be solved to obtain the EM
fields in a homogeneous anisotropic medium. For fields in
layered anisotropic media, the local transmission and
reflection matrices, the global reflection matrices, and the
recursion relations of the wave amplitudes at interfaces are
derived and used to express the EM fields in arbitrary
layers. The electric and magnetic dipole sources can locate
in arbitrary layers, and the medium can have both
full-tensor magnetic and dielectric anisotropy. The singular
behavior of the solution in the close vicinity of the dipole
source is subtracted to make the integrands decay rapidly as
functions of k x and k y. The contributions of the
subtracted part are calculated analytically. A three-layer
anisotropic medium is modeled to show the convergence of the
integrals with the singularity subtraction. To validate the
algorithm for multilayered generalized anisotropic media, a
five-layer medium is modeled and compared with finite
element method results. The algorithm is also applied in
geophysical EM well logging by modeling the triaxial
induction logging tool. The responses in vertical and
deviated wells are computed and compared with finite element
results. The good agreement between the two results further
validates the algorithm and demonstrates its capability to
model induction logging tools in multilayered generalized
anisotropic media.},
Doi = {10.1109/TGRS.2018.2825430},
Key = {fds340876}
}
@article{fds341137,
Author = {Song, Z and Chu, Q and Ye, L and Liu, Y and Zhu, C and Liu,
QH},
Title = {High-performance polarization beam splitter based on
anisotropic plasmonic nanostructures},
Journal = {Applied Physics B},
Volume = {124},
Number = {9},
Year = {2018},
Month = {September},
url = {http://dx.doi.org/10.1007/s00340-018-7049-z},
Abstract = {We propose an alternative design of efficient and compact
polarization beam splitters for wide-angle and
polarization-sensitive incidence of electromagnetic waves at
near-infrared frequencies. The designed system is
constructed by depositing periodic metallic strips on top
and bottom of a continuous metal film. Based on the
optimization of structure parameters, the whole system can
suppress transmission (~ 0%) for one polarization and
enhance transmission for another polarization (~ 95%). This
phenomenon of anisotropic transmission can be attributed to
different performances of impedance along different
polarization directions. This device may find applications
in optical components and polarization filter.},
Doi = {10.1007/s00340-018-7049-z},
Key = {fds341137}
}
@article{fds341138,
Author = {Li, C and Xu, L and Zhu, L and Zou, S and Liu, QH and Wang, Z and Chen,
H},
Title = {Concentrators for Water Waves.},
Journal = {Physical Review Letters},
Volume = {121},
Number = {10},
Pages = {104501},
Year = {2018},
Month = {September},
url = {http://dx.doi.org/10.1103/physrevlett.121.104501},
Abstract = {By introducing concepts from transformation optics to the
manipulation of water waves, we design and experimentally
demonstrate two annular devices for concentrating waves,
which employ gradient depth profiles based on Fabry-Pérot
resonances. Our measurements and numerical simulations
confirm the concentrating effect of the annular devices and
show that they are effectively invisible to the water waves.
We show that transformation optics is thus an effective
framework for designing devices to improve the efficiency of
wave energy collection, and we expect potential applications
in coastline ocean engineering.},
Doi = {10.1103/physrevlett.121.104501},
Key = {fds341138}
}
@article{fds340849,
Author = {Chen, J and Hao, G and Liu, QH},
Title = {Analyzing tunable terahertz grating based on hybrid
graphene-metal structure by using the HIE-FDTD
method},
Journal = {International Journal of Numerical Modelling: Electronic
Networks, Devices and Fields},
Volume = {31},
Number = {5},
Pages = {e2325-e2325},
Publisher = {WILEY},
Year = {2018},
Month = {September},
url = {http://dx.doi.org/10.1002/jnm.2325},
Abstract = {A hybrid graphene-metal grating is simulated and analyzed at
terahertz frequency band by using the hybrid
implicit-explicit finite-difference time domain (HIE-FDTD)
method. To simulate the graphene layer accurately, both the
interband and intraband conductivity of the graphene are
incorporated into the HIE-FDTD method by using the auxiliary
differential equations and Pade fitting technique. Numerical
results show that the HIE-FDTD method has excellent
computational accuracy and its computational efficiency is
considerably improved from that of the conventional FDTD
method. Besides, numerical results validate that the
graphene can achieve tunable terahertz grating through
controlling its chemical potential, and the interband
conductivity of the graphene has important effects on the
performance of the grating.},
Doi = {10.1002/jnm.2325},
Key = {fds340849}
}
@article{fds340948,
Author = {He, X and Lin, J and He, B and Xu, L and Li, J and Chen, Q and Yue, G and Xiong,
Q and Liu, QH},
Title = {The formation pathways of aqueous hydrogen peroxide in a
plasma-liquid system with liquid as the cathode},
Journal = {Plasma Sources Science and Technology},
Volume = {27},
Number = {8},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1088/1361-6595/aad66d},
Abstract = {Using an aqueous solution of NaCl as the cathode, we
explored the atmospheric pressure Ar discharge plasma
generated above the solution surface. The formation pathways
of aqueous hydrogen peroxide (H2O2aq) in this system were
investigated. Dimethyl sulfoxide was used as a scavenger of
hydroxyl (OH) radicals to investigate the contribution of
dissolved OH radicals to the H2O2aq. The results indicate
that the H2O2aq is mainly formed by the combination of the
dissolved OH radicals at the plasma-affected thin liquid
layer, while the H2O2 formed in the gas phase and the H2O2aq
formation inside water by the plasma-induced ultraviolet
radiation have no contribution.},
Doi = {10.1088/1361-6595/aad66d},
Key = {fds340948}
}
@article{fds341139,
Author = {Xie, J and Guo, Z and Liu, H and Liu, QH},
Title = {GPU acceleration of time gating based reverse time migration
using the pseudospectral time-domain algorithm},
Journal = {Computers & Geosciences},
Volume = {117},
Pages = {57-62},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1016/j.cageo.2018.05.006},
Abstract = {We present a Graphics Processing Units (GPU) implementation
of time gating based reverse time migration (TG-RTM) which
uses the pseudospectral time-domain (PSTD) algorithm to
solve the acoustic wave equation. TG-RTM adopts the prior
information of surrounding media to strengthen the
correlation between the wavefields, thus has advantages in
locating the targets over traditional reverse time migration
(RTM) methods. The PSTD algorithm adopts fast Fourier
transform (FFT) to obtain the spatial derivatives and a
perfectly matched layer as an absorbing boundary condition
to eliminate the wraparound effect introduced by the FFT
periodicity assumption. Under the Nyquist sampling theorem,
the spatial sampling density of the PSTD algorithm requires
only two points per minimum wavelength. Thus, the PSTD
algorithm can solve the time dependent partial differential
equations efficiently and save mass computer memory.
Compared with traditional RTM based on the finite difference
time domain (FDTD) algorithm, the proposed RTM based on the
PSTD algorithm can be implemented on a memory-limited GPU
and can solve much larger models. To secure a better
performance and generality of FFT in GPU, we present a
scheme which combines 1D FFT with matrix transpositions
instead of using 3D FFT directly. The matrix transpositions
use shared memory to improve memory access efficiency. We
also apply an efficient FFT scheme which replaces even-sized
R2C FFT with a half-sized C2C FFT. For a small amount and
balanced memory swapping from computer to GPU, we save the
boundaries in lieu of checkpointing scheme when we propagate
the source wavefield forward and backward. The proposed RTM
has an acceleration ratio of about 80 times by a Tesla K20X
GPU card on a desktop computer. The simulation results of 2D
and 3D models demonstrate that the proposed RTM is fast and
inexpensive.},
Doi = {10.1016/j.cageo.2018.05.006},
Key = {fds341139}
}
@article{fds341140,
Author = {Zhuo, J and Han, F and Ye, L and Yu, Z and Liu, QH},
Title = {Simulation of electromagnetic scattering of 3-D
inhomogeneous biaxial anisotropic magnetodielectric objects
embedded in uniaxial anisotropic media by the mixed-order
BCGS-FFT Method},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {66},
Number = {8},
Pages = {3745-3755},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1109/TMTT.2018.2840984},
Abstract = {This paper presents a volume integral equation (VIE) solver
for the forward electromagnetic scattering of 3-D
inhomogeneous biaxial anisotropic objects embedded in
uniaxial anisotropic media. The optical axes of the objects
can be rotated with arbitrary angles. The mixed-order basis
functions are employed to discretize the VIE, i.e., the flux
densities (D, B) are expanded by the volumetric rooftop
basis functions and the vector potentials (A, F) are
expanded by the second-order curl conforming basis
functions. The weak form of the VIE is formulated by testing
it using the same volumetric rooftop basis function and
solved by the biconjugate gradient stabilized fast Fourier
transform (BCGS-FFT) method. Several numerical simulations
of different shapes anisotropic objects are performed and
the results are compared with commercial software
simulations to validate the accuracy and efficiency of the
proposed solver based on different discretization schemes.
The major new contribution of this paper is that not only
the scatterer but also the background medium is
magnetodielectrically anisotropic. Therefore, the dyadic
Green's function for the uniaxial anisotropic background
medium is evaluated before solving the VIE.},
Doi = {10.1109/TMTT.2018.2840984},
Key = {fds341140}
}
@article{fds341141,
Author = {Zheng, J and Liu, H and Liu, J and Du, X and Liu, QH},
Title = {Radar High-Speed Maneuvering Target Detection Based on
Three-Dimensional Scaled Transform},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {11},
Number = {8},
Pages = {2821-2833},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1109/JSTARS.2018.2846731},
Abstract = {This paper presents a novel coherent high-speed maneuvering
target detection algorithm, which is based on the
three-dimensional (3-D) scaled transform. This algorithm
coherently integrates the echo energy into a peak in a 3-D
parameter space and estimates the target's radial velocity
and acceleration simultaneously by the peak detection
technique. Thereafter, compensating off the across range
unit and Doppler frequency migration via estimations, this
algorithm coherently integrates the echo energy in the
range-Doppler space and uses the constant false alarm rate
technique to complete the target detection. The cross term
of the proposed algorithm is also analyzed and its
characteristic indicates the applicability in the scenario
of multiple targets. The computational complexity,
resolution, peak-to-sidelobe level (PSL), and detection
performance are analyzed and compared with several typical
algorithms, which leads us to conclude that the proposed
algorithm can strike a balance between the computational
complexity and detection performance with high resolution
and PSL. Finally, experiments with the real measured radar
data are conducted to verify the proposed
algorithm.},
Doi = {10.1109/JSTARS.2018.2846731},
Key = {fds341141}
}
@article{fds341142,
Author = {Liu, H and Long, Z and Han, F and Fang, G and Liu, QH},
Title = {Frequency-Domain Reverse-Time Migration of Ground
Penetrating Radar Based on Layered Medium Green's
Functions},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {11},
Number = {8},
Pages = {2957-2965},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1109/JSTARS.2018.2841361},
Abstract = {A frequency-domain reverse-time migration (RTM) algorithm
based on the layered medium dyadic Green's function (DGF) is
proposed for high-resolution and efficient subsurface
imaging using ground penetrating radar (GPR). Different from
the conventional RTM, which is performed by the
finite-difference time domain (FDTD) method, both the
forward and backward extrapolation wavefields in this
frequency-domain RTM are computed by the multiplication
between the frequency spectra of the excitation source or
the recorded GPR data and the layered medium DGFs. The final
image is reconstructed by the direct summation of all the
wavefields for all the sampling frequencies in the frequency
domain, instead of transforming them back to the time domain
and processing them. Two-dimensional (2-D) or 3-D numerical
and laboratory experiments show that the proposed
frequency-domain RTM algorithm can yield almost the same
imaging results as the conventional time domain RTM
algorithm but requires less than two orders of magnitude in
computational costs. The proposed GPR imaging method is
verified to be competent for the fast 3-D imaging of
potential larva rocks under the lunar surface, which can
provide critical information for the regolith-drilling task
of the Chang-E 5 lunar exploration mission of China.
Real-time subsurface imaging by RTM could be fulfilled and
be widely applied to engineering geophysics, such as urban
utility detection, through-wall imaging, and ice monitoring
by ground-coupled or air-borne GPR.},
Doi = {10.1109/JSTARS.2018.2841361},
Key = {fds341142}
}
@article{fds341063,
Author = {Li, WW and Qin, ZZ and Chen, SJ and Zhang, L and Liu,
QH},
Title = {A wideband printed slot antenna with harmonic
suppression},
Journal = {Microwave and Optical Technology Letters},
Volume = {60},
Number = {8},
Pages = {1946-1952},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.1002/mop.31278},
Abstract = {A wideband slot antenna with harmonic suppression is
proposed to utilize the environment microwave energy. The
antenna element is a printed narrow slot with an offset
microstrip-feed line to widen the operating band by
generating the double resonance of similar frequencies. By
adding a rectangular notch in the middle of slot element and
grounding the microstrip terminal, its second-order and
third-order harmonics are effectively suppressed. The
experimental results of the prototype antenna show that the
fractional bandwidth of its fundamental mode can reach
37.4%, while the antenna efficiencies of the second and
third harmonics both are less than 23%. In the operating
band the prototype antenna has the approximately
omnidirectional radiation characteristic. This antenna
structure also provides relaxed fabrication
tolerances.},
Doi = {10.1002/mop.31278},
Key = {fds341063}
}
@article{fds340801,
Author = {Chu, Q and Song, Z and Liu, QH},
Title = {Omnidirectional tunable terahertz analog of
electromagnetically induced transparency realized by
isotropic vanadium dioxide metasurfaces},
Journal = {Applied Physics Express},
Volume = {11},
Number = {8},
Pages = {082203-082203},
Publisher = {Japan Society of Applied Physics},
Year = {2018},
Month = {August},
url = {http://dx.doi.org/10.7567/APEX.11.082203},
Abstract = {We present an isotropic active analog of electromagnetically
induced transparency through conductivity tuning of vanadium
dioxide at terahertz frequencies. The unit cell of the
designed metasurface consists of metallic split ring
resonators and a metallic cross, which have identical
resonance frequencies for the excitable lowest order modes
but very different linewidths. By integrating vanadium
dioxide into the bottom of the metasurface, an obvious
tuning of the transparency window occurs under different
conductivities. Calculated results show that resonant
transmission frequency of the electromagnetically induced
transparency remains stable with respect to the polarization
and incident angle of electromagnetic waves.},
Doi = {10.7567/APEX.11.082203},
Key = {fds340801}
}
@article{fds341143,
Author = {Li, YK and Hu, J and Nie, Z and Liu, QH},
Title = {Fast integral equation methods for solving scattering from
bodies of revolution (invited)},
Journal = {2017 Ieee 6th Asia Pacific Conference on Antennas and
Propagation, Apcap 2017 Proceeding},
Pages = {1-3},
Year = {2018},
Month = {July},
ISBN = {9781538616086},
url = {http://dx.doi.org/10.1109/APCAP.2017.8420655},
Abstract = {The analysis of scattering from multiple Bodies of
Revolution (BoR) has important applications in microwave
remote sensing, radar imaging and other areas. Due to the
rotational symmetry, the three dimensional scattering and
radiation problems from BoR structures can be reduced to
series of two dimensional problems and solved by method of
moment(BoR-MoM). This characteristic greatly reduced both
the computational time and storage for solving this kind of
problems. To further improve the efficiency of the BoR
method, a spectral integral method is applied to combined
with the BoR method for the single BoR problems.
Furthermore, to extend the application of BoR method to
multiple BoRs problems, two methods are introduced: The mode
characteristic basis function method is applied as a direct
solver for the multiple right-hand problems, while a fast
iterative solver based on the multi-region iterative method
is applied which is more suitable for the mono right-hand
problems. The typical numerical results for all the methods
are given to demonstrate the accuracy and
efficiency.},
Doi = {10.1109/APCAP.2017.8420655},
Key = {fds341143}
}
@article{fds340812,
Author = {Hong, R and Li, S and Zhang, J and Zhang, Y and Liu, N and Yu, Z and Liu,
QH},
Title = {A volume integral equation method for MRI-based electrical
properties tomography},
Journal = {2017 Ieee 6th Asia Pacific Conference on Antennas and
Propagation, Apcap 2017 Proceeding},
Pages = {1-3},
Publisher = {IEEE},
Year = {2018},
Month = {July},
ISBN = {9781538616086},
url = {http://dx.doi.org/10.1109/APCAP.2017.8420782},
Abstract = {A volume integral equation method is presented for MRI-based
electrical properties tomography (EPT). The distortion of
radiofrequency magnetic field in MRI is an electromagnetic
scattering problem. Thus, the volume integral equation is
appropriate to solve the problem. Significant errors along
boundaries of different media may occur when the traditional
EPT method is applied to reconstructed the electrical
properties. The proposed method can greatly reduce the
errors, and the numerical result shows that it performs well
in inhomogeneous regions and boundaries where the electrical
properties vary abruptly.},
Doi = {10.1109/APCAP.2017.8420782},
Key = {fds340812}
}
@article{fds336188,
Author = {Ye, L and Chen, X and Cai, G and Zhu, J and Liu, N and Liu,
QH},
Title = {Electrically Tunable Broadband Terahertz Absorption with
Hybrid-Patterned Graphene Metasurfaces.},
Journal = {Nanomaterials (Basel, Switzerland)},
Volume = {8},
Number = {8},
Pages = {E562},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.3390/nano8080562},
Abstract = {We numerically demonstrate a broadband terahertz (THz)
absorber that is based on a hybrid-patterned graphene
metasurface with excellent properties of polarization
insensitivity, wide-angle, and active tunability. Our design
is made up of a single-layer graphene with periodically
arranged hybrid square/disk/loop patterns on a multilayer
structure. We find that broadband absorption with 90%
terahertz absorbance and the fractional bandwidth of 84.5%
from 1.38 THz to 3.4 THz can be achieved. Because of the
axisymmetric configuration, the absorber demonstrates
absolute polarization independence for both transverse
electric (TE) and transverse magnetic (TM) polarized
terahertz waves under normal incidence. We also show that a
bandwidth of 60% absorbance still remains 2.7 THz, ranging
from 1.3 THz to 4 THz, for a wide incident angle ranging
from 0° to 60°. Finally, we find that by changing the
graphene Fermi energy from 0.7 eV to 0 eV, the absorbance of
the absorbers can be easily tuned from more than 90% to
lower than 20%. The proposed absorber may have promising
applications in terahertz sensing, detecting, imaging, and
cloaking.},
Doi = {10.3390/nano8080562},
Key = {fds336188}
}
@article{fds341144,
Author = {Song, Z and Chu, Q and Liu, QH},
Title = {Isotropic wide-angle analog of electromagnetically induced
transparency in a terahertz metasurface},
Journal = {Materials Letters},
Volume = {223},
Pages = {90-92},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1016/j.matlet.2018.04.015},
Abstract = {We present a terahertz classical analog of
electromagnetically induced transparency by means of
single-layer metamaterial consisting of two closed square
ring. The narrow transparency peak is mainly caused by the
excitation of antiparallel currents in different rings.
Because of symmetry configuration, the designed metamaterial
possesses stable polarization-independent and wide-angle
transmission spectral features. Moreover, the design has a
simple structure ideally suitable for the current planar
micro- and nano-fabrications.},
Doi = {10.1016/j.matlet.2018.04.015},
Key = {fds341144}
}
@article{fds340740,
Author = {Huang, Y and Zhao, Z and Qi, C and Nie, Z and Liu, QH},
Title = {Fast Point-Based KD-Tree Construction Method for Hybrid High
Frequency Method in Electromagnetic Scattering},
Journal = {Ieee Access},
Volume = {6},
Pages = {38348-38355},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1109/ACCESS.2018.2853659},
Abstract = {Owing to its advantage in fast calculation, ray-tracing
technique has been widely applied in solving electromagnetic
scattering of electrically large target. In order to save
computational time in ray tracing, KD-tree structure is
introduced to reduce the number of ray-scene intersection
tests. Nevertheless, KD-tree construction usually becomes
the most time-consuming step in the implementation of ray
tracing. In this paper, a point-based KD-tree construction
method (PKCM) is proposed to accelerate the construction of
KD-tree. The basic idea is to substitute point numbers for
facet numbers to accelerate the process of probing optimal
splitting plane with surface area heuristic. Owing to this
replacement, the searching area of PKCM is dramatically
decreased compared with that of KD-tree structure with
facets, thus giving rise to significant saving in
computational time but without degrading performance.
Simulations of the scattering of electrically large complex
objects demonstrate the effectiveness of the proposed
PKCM.},
Doi = {10.1109/ACCESS.2018.2853659},
Key = {fds340740}
}
@article{fds341145,
Author = {Fang, Y and Hu, Y and Zhan, Q and Liu, QH},
Title = {Electromagnetic Forward and Inverse Algorithms for 3-D
Through-Casing Induction Mapping of Arbitrary
Fractures},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {15},
Number = {7},
Pages = {996-1000},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1109/LGRS.2018.2818112},
Abstract = {This letter extends the axisymmetric version of the
efficient forward and inverse algorithms to characterize and
reconstruct arbitrary 3-D fractures in a cased borehole
environment. We improve our previous hybrid distorted Born
approximation and stabilized biconjugate gradient fast
Fourier transform method as the 3-D forward modeling
algorithm that can significantly reduce the computational
cost in forward modeling. The bounding constraints and model
parameter transformation functions are introduced to our
previous axisymmetric variational Born iterative inverse
method to effectively reconstruct 3-D fractures. Numerical
results show orders of magnitude higher efficiency of the
forward algorithm than the finite-element method, and the
effectiveness of the inverse algorithm for through-casing
3-D fracture reconstruction.},
Doi = {10.1109/LGRS.2018.2818112},
Key = {fds341145}
}
@article{fds341146,
Author = {Yao, J and Cai, G and Liu, N and Liu, QH},
Title = {Enhancing artificial sum frequency generation from
graphene-gold metamolecules.},
Journal = {Optics Letters},
Volume = {43},
Number = {13},
Pages = {3160-3163},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1364/ol.43.003160},
Abstract = {The enhanced artificial sum frequency generation (SFG) is
realized by graphene-gold metamolecules at the mid-infrared
without any natural nonlinear material. The unit cell of the
proposed metamolecules combines an inner graphene cut-wire
meta-atom and an outer gold split-ring resonator meta-atom.
In order to achieve high efficiency of the artificial SFG,
not only the novel material of graphene with high mobility
is used as the constituent material, but also the double
resonances at two fundamental frequencies are excited to
form an intensive magnetic Lorentz force. Both time domain
response and frequency domain response are analyzed
numerically. Results show that the SFG efficiency is at
least two orders of magnitude larger than that of
second-harmonic generation, which involves only a single
resonance. The tunability of graphene on the SFG is studied
as well. This work will facilitate the engineering of
nonlinear metamaterials, whose nonlinear properties can be
customized by artificial structuring, in their practical
applications.},
Doi = {10.1364/ol.43.003160},
Key = {fds341146}
}
@article{fds341064,
Author = {Xu, KD and Zhang, F and Liu, Y and Liu, QH},
Title = {Bandpass Filter Using Three Pairs of Coupled Lines with
Multiple Transmission Zeros},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {28},
Number = {7},
Pages = {576-578},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1109/LMWC.2018.2835643},
Abstract = {A novel but very simple bandpass filter using just three
pairs of coupled lines with multiple transmission zeros
(TZs) and transmission poles is proposed in this letter. The
filter structure can be seen as the two one-wavelength ring
resonators coupled each other with \lambda -{g}/4 coupled
length and sandwiched between the 3\lambda -{g}/4 input and
output feedlines. Good out-of-band suppression and sharp
roll-off skirts can be realized by multiple fixed and
tunable TZs without complicated coupling scheme. For further
demonstration, a filter example with center frequency at
f-{0}= 2.1 GHz is implemented with generation of eight TZs
at the frequency range from 0 to 2f-{0} for theoretically
calculated certification. Good agreement between simulation
and measured results validates the design
method.},
Doi = {10.1109/LMWC.2018.2835643},
Key = {fds341064}
}
@article{fds341100,
Author = {Song, T and Kuang, L and Han, L and Wang, Y and Liu,
QH},
Title = {Inversion of Rough Surface Parameters from SAR Images Using
Simulation-Trained Convolutional Neural Networks},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {15},
Number = {7},
Pages = {1130-1134},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1109/LGRS.2018.2822821},
Abstract = {This letter investigates the inversion of rough surface
parameters (the root mean square height and the correlation
length) from microwave images by using deep convolutional
neural networks (CNNs). Training data for the deep CNN are
simulated numerically using computational electromagnetic
method. As CNN is powerful in extracting image features,
scattering field from rough surfaces is first converted to
microwave images via interpolated fast Fourier transform and
then fed into the CNN. In order to reduce overfitting, the
regularization technique and dropout layer are used. The
proposed CNN consists of five pairs of convolutional and
maxpooling layers and two additional convolution layers for
feature extraction and two fully connected layers for
parameter regression. The experimental results demonstrated
the feasibility using deep neural networks for the parameter
inversion of rough surface from electromagnetic scattering
fields. It suggests potential application of CNN for rough
surface parameter inversion from microwave sensing
data.},
Doi = {10.1109/LGRS.2018.2822821},
Key = {fds341100}
}
@article{fds340738,
Author = {Zhou, J and Yan, S and Li, C and Zhu, J and Liu, QH},
Title = {Perfect ultraviolet absorption in graphene using the
magnetic resonance of an all-dielectric nanostructure.},
Journal = {Optics Express},
Volume = {26},
Number = {14},
Pages = {18155-18163},
Year = {2018},
Month = {July},
url = {http://dx.doi.org/10.1364/oe.26.018155},
Abstract = {The enhancement of light-matter interaction for monolayer
graphene is of great importance on many photonic and
optoelectronic applications. With the aim of perfect
ultraviolet trapping on monolayer graphene, we adopt the
design of an all-dielectric nanostructure, in which the
magnetic resonance of optical field is combined with an
ultraviolet mirror. The physics inside is revealed in
comparison with the conventional plasmonic perfect absorber,
and various influence factors of absorption bands are
systematically investigated. In the ultraviolet range, an
optimized absorbance ratio up to 99.7% is reached, which is
10 times more than that of the suspended graphene, and the
absorption bands are linearly reconfigurable by angular
manipulation of incident light. The scheme for perfect
ultraviolet trapping in a sub-nanometer scale paves the way
for developing more promising ultraviolet devices based on
graphene and potentially other 2D materials.},
Doi = {10.1364/oe.26.018155},
Key = {fds340738}
}
@article{fds341147,
Author = {Li, W and Li, P and Zhou, J and Liu, QH},
Title = {Control of higher order harmonics and spurious modes for
microstrip patch antennas},
Journal = {Ieee Access},
Volume = {6},
Pages = {34158-34165},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1109/ACCESS.2018.2850858},
Abstract = {In rectifying or active antenna systems, the higher order
modes can hamper the system efficiency, and thus, the filter
antennas are used to eliminate the harmonic radiation. In
this paper, the distribution of standing wave fields in
patch antenna having been presented and then the
characteristic mode theory having been employed, the
influences of feeding location and the indentation of patch
edges on the suppression of higher order harmonics and their
spurious modes are investigated. It is indicated that
indenting the radiating edges of the patch element works
more effectively on the control of spurious modes while
indenting the non-radiating edges can eliminate the
harmonics by shifting down the fundamental mode. By
selecting feed position and indenting the patch edges, a
microstrip patch antenna with both harmonic and spurious
mode controls is proposed.},
Doi = {10.1109/ACCESS.2018.2850858},
Key = {fds341147}
}
@article{fds340739,
Author = {Liu, S and Zhao, Z and Lu, Y and Wang, B and Nie, Z and Liu,
QH},
Title = {Microwave induced thermoacoustic tomography based on
probabilistic reconstruction},
Journal = {Applied Physics Letters},
Volume = {112},
Number = {26},
Pages = {263701-263701},
Publisher = {AIP Publishing},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1063/1.5034485},
Abstract = {The performance of the existing reconstruction algorithms
based on compressive sensing (CS) in microwave induced
thermoacoustic tomography (MITAT) is influenced by the
positions of detectors. Besides, some a priori information,
such as target distribution or the correlation among
thermoacoustic signals, has not been taken into account. In
this letter, a probabilistic reconstruction algorithm in
MITAT based on sparse Bayesian learning is proposed.
Different from norm-based point estimation algorithms in CS,
the sound pressure distribution which needs to be estimated
is provided by probability distributions in the
probabilistic reconstruction algorithm and an image is
reconstructed based on the posterior density. Compared with
the widely used norm-based point estimation algorithms
(GPSR, Lasso) whose solution is not always the sparsest, the
sparse Bayesian learning framework is globally convergent
which can produce the sparsest solution at the posterior
mean. Therefore, the robustness of the probabilistic
reconstruction is better than that of norm-based point
estimation algorithms. In addition, the estimations of the
initial pressure distributions can be more accurately
provided if the correlation of thermoacoustic signals can be
considered, especially under the condition of low signal to
noise ratio (SNR). Simulations and experiments on real
breast tumors demonstrate that the proposed algorithm
improves the robustness of reconstruction and show better
performance at low SNRs.},
Doi = {10.1063/1.5034485},
Key = {fds340739}
}
@article{fds341065,
Author = {Xu, KD and Li, D and Liu, Y and Liu, QH},
Title = {Printed Quasi-Yagi Antennas Using Double Dipoles and
Stub-Loaded Technique for Multi-Band and Broadband
Applications},
Journal = {Ieee Access},
Volume = {6},
Pages = {31695-31702},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1109/ACCESS.2018.2838328},
Abstract = {Double dipoles on a single-layer substrate are utilized to
construct a triple-mode printed quasi-Yagi antenna for the
multi-band and broadband antenna applications. A stub-loaded
dipole generating two resonant modes (i.e., lower dual-mode
dipole) is allocated on the underside of a simple dipole
(i.e., upper single-mode dipole) introducing the third
resonant mode. Using these three resonant modes, three
compact printed quasi-Yagi antennas, i.e., tri-band,
dual-band, and broadband printed quasi-Yagi antennas, are
designed with the same antenna prototype but different
parameter values. Seen from the measured results, all of
these three antennas have good unidirectional radiations,
high radiation efficiencies, and low cross-polarization
levels at the operating frequencies within the impedance
bandwidths.},
Doi = {10.1109/ACCESS.2018.2838328},
Key = {fds341065}
}
@article{fds341148,
Author = {Zheng, J and Liu, H and Liu, J and Liu, QH},
Title = {ImPCFCRD for noisy multicomponent LFM signals
analysis},
Journal = {2018 Ieee Radar Conference, Radarconf 2018},
Pages = {519-524},
Year = {2018},
Month = {June},
ISBN = {9781538641675},
url = {http://dx.doi.org/10.1109/RADAR.2018.8378613},
Abstract = {This paper presents the improved parameterized centroid
frequency-chirp rate distribution (ImPCFCRD) for noisy
multicomponent linear frequency modulated (LFM) signals
analysis. Theoretical analyses and illustrative examples are
performed for the ImPCFCRD. Mathematical conclusions and
simulation results demonstrate that the ImPCFCRD makes the
most of the constant delay introduction and achieves the
theoretically optimal in the PSL. Finally, an experiment is
given to illustrate that, because of the high PSL, the
ImPCFCRD is more suitable for noisy multicomponent LFM
signals analysis.},
Doi = {10.1109/RADAR.2018.8378613},
Key = {fds341148}
}
@article{fds341150,
Author = {Feng, N and Zhang, Y and Sun, Q and Zhu, J and Joines, WT and Liu,
QH},
Title = {An Accurate 3-D CFS-PML Based Crank-Nicolson FDTD Method and
Its Applications in Low-Frequency Subsurface
Sensing},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {66},
Number = {6},
Pages = {2967-2975},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1109/TAP.2018.2816788},
Abstract = {An unsplit-field and accurate Crank-Nicolson
cycle-sweep-uniform finite-difference time-domain
(CNCSU-FDTD) method based on the complex-frequency-shifted
perfectly matched layer (CFS-PML) is proposed. It is applied
to 3-D low-frequency subsurface electromagnetic sensing
problems. The presented CNCSU-FDTD takes advantage of both
CFS-PML and unconditionally stable CN method so that it can
attenuate evanescent waves, eliminate late-time reflections,
and overcome the stability limits of the FDTD method. The
time step intervals in CNCSU-FDTD can be 1000 times larger
than that in the regular FDTD for the low-frequency sensing
centered at 25 Hz while remaining accurate. Several 3-D
numerical examples in the airborne transient
electromagnetics system have been demonstrated to validate
the proposed method. The CFS-PML-based CNCSU-FDTD method not
only attains good accuracy but also saves several dozen
times of CPU time as compared with the regular FDTD
method.},
Doi = {10.1109/TAP.2018.2816788},
Key = {fds341150}
}
@article{fds341151,
Author = {Liu, H and Hong, D and Li, N and Han, W and Liu, QH},
Title = {Solving Electromagnetic Fields by General
Reflection\Transmission Method for Coaxial-Coil Antenna in
Cylindrically Multilayered Medium},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {15},
Number = {6},
Pages = {912-916},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1109/LGRS.2018.2814614},
Abstract = {In this letter, we present a set of compact and no-overflow
formulations to calculate the electromagnetic (EM) fields
from coaxial coil antennas in a concentric cylindrically
multilayered medium. It can be applied to fast forward
computation and the inverse problem for EM well logging. The
derivation is performed by using the tangential component of
electric field. In contrast with previous formulations, the
adopted novel reflection and transmission coefficients are
scalars rather than matrices, which make it easy to get an
accurate and efficient Jacobian matrix for inversion
problem. The basic unit of the formulations is the ratio of
the cylindrical functions so that the notorious overflow
problem for numerical computation can be obviated. Numerical
results in comparison with those from other approaches have
demonstrated the validity and stability of our new
formulations for forward modeling. To show the potential of
the proposed formulations, an inverse result from a simple
formation model is also presented.},
Doi = {10.1109/LGRS.2018.2814614},
Key = {fds341151}
}
@article{fds341149,
Author = {Liu, Y and Bai, J and Xu, KD and Xu, Z and Han, F and Liu, QH and Jay Guo,
Y},
Title = {Linearly Polarized Shaped Power Pattern Synthesis With
Sidelobe and Cross-Polarization Control by Using
Semidefinite Relaxation},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {66},
Number = {6},
Pages = {3207-3212},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1109/TAP.2018.2816782},
Abstract = {In this communication, the problem of synthesizing a
linearly polarized shaped power pattern with accurate
control on both sidelobe and cross-polarization (XP) levels
is considered. For a user-defined desired polarization
direction, the definitions of realizable co-polarization
(COP) and XP directions for an arbitrary propagation
direction in the shaped pattern are presented. With the help
of such definitions, the considered problem is formulated as
finding appropriate excitations so as to produce a shaped
power pattern in which the realizable COP component meets
prescribed lower and upper bounds, the realizable XP
component and the total power pattern are less than their
upper bounds in the regions of interest. The semidefinite
relaxation method in the literature is then extended to
solve this vectorial pattern synthesis problem. The proposed
method can include the mutual coupling and platform effects
by using vectorial active element patterns of an antenna
array. A set of synthesis examples with different array
geometries and radiation requirements are conducted to
validate the effectiveness and advantages of the proposed
method.},
Doi = {10.1109/TAP.2018.2816782},
Key = {fds341149}
}
@article{fds340802,
Author = {Zhang, X and Zhou, R and Bazaka, K and Liu, Y and Chen, G and Chen, Z and Liu,
Q and Yang, S and Ostrikov, K},
Title = {Quantification of plasma produced OH radical density for
water sterilization},
Journal = {Plasma Processes and Polymers},
Volume = {15},
Number = {6},
Pages = {1700241-1700241},
Publisher = {WILEY},
Year = {2018},
Month = {June},
url = {http://dx.doi.org/10.1002/ppap.201700241},
Abstract = {The interactions between plasma-generated excited particles
and water play an integral role in sustainable degradation
of pharmaceutical compounds, improving aerobic respiration
of activated sludge, and efficient removal of microorganisms
from water, and are fundamental to the intentional transfer
of reactivity from plasmas to biological solutions for such
medical applications as cancer treatment and wound healing.
The physical and chemical mechanisms that govern this
transfer of reactivity are complex, and include concomitant
generation and consumption of species in the gas and liquid
phases, and at the interface. As such, it is challenging to
predict the quantities of biologically-active radicals and
molecules in liquid phase from gas phase measurements alone.
Rapid and accurate quantification of reactive species, such
as OH radicals and H2O2 molecules within the liquid phase
and their link to specific biological effects is therefore
critical for medical applications of plasma-activated
solutions. Using a simple, low-cost method for trapping and
stabilization of OH radicals by means of salicylic acid,
this work seeks to provide further insights into the physics
and chemistry of generation of OH radicals within the liquid
phase, and integrate these findings with decontamination
outcomes for four commonly used processing
gases.},
Doi = {10.1002/ppap.201700241},
Key = {fds340802}
}
@article{fds341152,
Author = {Mao, Y and Niu, J and Liu, QH},
Title = {Spectral element boundary integral method for rapid and
accurate simulations of inhomogeneous objects in layered
media in nanophotonics},
Journal = {2018 International Applied Computational Electromagnetics
Society Symposium in Denver, Aces Denver
2018},
Year = {2018},
Month = {May},
ISBN = {9780996007870},
url = {http://dx.doi.org/10.23919/ROPACES.2018.8364229},
Abstract = {We recently developed an efficient numerical solver, the
spectral element boundary integral (SEBI) method with the
periodic layered medium dyadic Green's functions, to perform
rapid and accurate simulations in nanophotonic applications.
The problem is Bloch (Floquet) periodic in the lateral
directions but has a multilayer background medium in the
vertical direction, and arbitrary objects are embedded in
the layered medium. We employ the periodic layered medium
dyadic Green's function, and the surface integral equations
as the radiation boundary condition to truncate the top and
bottom computation boundaries of the interior domain that is
simulated by the spectral element method. Therefore, all
multiple scatterings within the top and bottom layered media
have been analytically accounted for in the radiation
boundary condition, and the computational domain is only
limited to the inhomogeneous objects embedded in the layered
medium. Consequently, this SEBI solver can be much more
efficient than conventional methods. We demonstrate the
accuracy and efficiency of this solver for several typical
nanophotonic applications.},
Doi = {10.23919/ROPACES.2018.8364229},
Key = {fds341152}
}
@article{fds341153,
Author = {Ma, X and Liu, Y and Da Xu and K and Zhu, C and Liu, QH},
Title = {Synthesising multiple-pattern sparse linear array with
accurate sidelobe control by the extended reweighted L1-norm
minimisation},
Journal = {Electronics Letters},
Volume = {54},
Number = {9},
Pages = {548-550},
Year = {2018},
Month = {May},
url = {http://dx.doi.org/10.1049/el.2018.0333},
Abstract = {The problem of synthesising a sparse linear array with
multiple patterns is formulated as an extended reweighted
ℓ1-norm minimisation with multiple convex constraints.
Synthesis results show that the proposed method can find the
common sparse element positions with optimised excitations
for multiple-pattern requirements, and the mainlobe,
sidelobe as well as nulling region for each pattern can be
accurately controlled.},
Doi = {10.1049/el.2018.0333},
Key = {fds341153}
}
@article{fds341154,
Author = {Yang, H and Li, N and Li, T and Liu, QH},
Title = {Least-Square-Based Nonuniform Borehole SAR Imaging for
Subsurface Sensing},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {11},
Number = {5},
Pages = {1545-1555},
Year = {2018},
Month = {May},
url = {http://dx.doi.org/10.1109/JSTARS.2018.2813338},
Abstract = {This paper presents the least-square-based nonuniform
borehole synthetic aperture radar (SAR) imaging method with
cosine accuracy factor for subsurface sensing. Based on the
Stolt migration, the frequency-wavenumber spectrum of
nonuniform data is efficiently approximated in the
least-square-sense for the target space generation. The
nonuniform power exponent basis is interpolated into several
uniform power exponent bases with cosine accuracy factors,
and then a virtual uniform sample set with a larger scale is
generated for frequency-wavenumber spectrum approximation
and imaging process. The proposed method can give accurate
subsurface image result with nonuniform data at a greatly
reduced computational cost. The approximation error and
computational cost of the proposed method are analyzed and
compared with those of Gaussian nonuniform imaging method.
The imaging capabilities of the proposed method are
theoretically simulated and experimentally demonstrated for
distributed targets. The results show that the normalized
mean square error and normalized maximum error of the
proposed method are at least 8.07 dB and 4.29 dB,
respectively, lower than those of conventional Stolt
migration method. The imaging properties of this proposed
method are shown to be superior to the conventional Stolt
migration method, Gaussian nonuniform imaging method and
Kirchhoff migration method, which is suitable for large
nonuniform SAR imaging applications.},
Doi = {10.1109/JSTARS.2018.2813338},
Key = {fds341154}
}
@article{fds340850,
Author = {Jiang, W and Liu, J and Li, Q and Xia, T and Hu, X and Liu,
QH},
Title = {Are There the Pure TE and TM Modes in the Closed Waveguide
Filled with a Homogeneous, Anisotropic and Lossless
Medium?},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {66},
Number = {5},
Pages = {2439-2448},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {May},
url = {http://dx.doi.org/10.1109/TAP.2018.2814061},
Abstract = {Using the Abelian group theory and the classic
electromagnetic waveguide theory, we propose a sufficient
condition for the existence of the pure TE and TM modes in
the closed waveguide filled with a homogeneous, anisotropic,
and lossless medium. This sufficient condition is the
relation between the permittivity and permeability tensors.
Four eigenvalue problems that can be used to simulate the
pure TE and TM modes in the anisotropic waveguide are
derived from source-free Maxwell's equations. Two of them
are eigenvalue problems of the elliptic differential
operator, and the other two are eigenvalue problems of the
curl-curl operator. Moreover, we solve these four eigenvalue
problems by the finite element method. Finally, we carry out
some numerical experiments to verify our theoretical
results.},
Doi = {10.1109/TAP.2018.2814061},
Key = {fds340850}
}
@article{fds341155,
Author = {Zhang, J and Wang, CZ and Zhu, Z and Liu, QH and Ho,
KM},
Title = {Multimode Jahn-Teller effect in bulk systems: A case of the
N V0 center in diamond},
Journal = {Physical Review B},
Volume = {97},
Number = {16},
Year = {2018},
Month = {April},
url = {http://dx.doi.org/10.1103/PhysRevB.97.165204},
Abstract = {The multimode Jahn-Teller (JT) effect in a bulk system of a
neutral nitrogen-vacancy (NV0) center in diamond is
investigated via first-principles density-functional-theory
calculations and the intrinsic distortion path (IDP) method.
The adiabatic potential energy surface of the electronic
ground state of the NV0 center is calculated based on the
local spin-density approximation. Our calculations confirm
the presence of the dynamic Jahn-Teller effect in the ground
E2 state of the NV0 center. Within the harmonic
approximation, the IDP method provides the reactive path of
JT distortion from unstable high-symmetry geometry to stable
low-symmetry energy minimum geometry, and it describes the
active normal modes participating in the distortion. We find
that there is more than one vibrational mode contributing to
the distortion, and their contributions change along the
IDP. Several vibrational modes with large contributions to
JT distortion, especially those modes close to 44 meV, are
clearly observed as the phonon sideband in photoluminescence
spectra in a series of experiments, indicating that the
dynamic Jahn-Teller effect plays an important role in the
optical transition of the NV0 center.},
Doi = {10.1103/PhysRevB.97.165204},
Key = {fds341155}
}
@article{fds341156,
Author = {Zhu, J and Yan, S and Feng, N and Ye, L and Ou, JY and Liu,
QH},
Title = {Near unity ultraviolet absorption in graphene without
patterning},
Journal = {Applied Physics Letters},
Volume = {112},
Number = {15},
Year = {2018},
Month = {April},
url = {http://dx.doi.org/10.1063/1.5022768},
Abstract = {Enhancing the light-matter interaction of graphene is an
important issue for related photonic devices and
applications. In view of its potential ultraviolet
applications, we aim to achieve extremely high ultraviolet
absorption in graphene without any nanostructure or
microstructure patterning. By manipulating the polarization
and angle of incident light, the ultraviolet power can be
sufficiently coupled to the optical dissipation of graphene
based on single-channel coherent perfect absorption in an
optimized multilayered thin film structure. The ultraviolet
absorbance ratios of single and four atomic graphene layers
are enhanced up to 71.4% and 92.2%, respectively. Our
research provides a simple and efficient scheme to trap
ultraviolet light for developing promising photonic and
optoelectronic devices based on graphene and potentially
other 2D materials.},
Doi = {10.1063/1.5022768},
Key = {fds341156}
}
@article{fds341157,
Author = {Liu, H and Xing, B and Zhu, J and Zhou, B and Wang, F and Xie, X and Liu,
QH},
Title = {Quantitative Stability Analysis of Ground Penetrating Radar
Systems},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {15},
Number = {4},
Pages = {522-526},
Year = {2018},
Month = {April},
url = {http://dx.doi.org/10.1109/LGRS.2018.2801827},
Abstract = {The hardware instability of a ground penetrating radar (GPR)
system has a severe impact on the quantitative analysis of
GPR data, which is aimed for material characterization and
subsurface monitoring. In this letter, an instability index
is proposed to quantify the stability performance of a GPR
system and the influences of the GPR system type, warm-up
time, environmental noise, and the antenna vibration on it
are evaluated through a series of laboratory experiments on
a sandbox model. It is found that the GPR signal recorded by
a stepped-frequency GPR system based on a vector network
analyzer is much more stable than that by a commercial
impulse GPR system at a cost of more sweep time. A warm-up
time of several minutes is enough for an impulse GPR system.
Environmental noise has a negligible influence on the
stability performance of a GPR system. Mechanical vibrations
of GPR antennas have a severe impact on the stability
performance of the GPR system, and the instability index and
timing jitter can be increased by more than one order of
magnitude in a vibrating condition over those in a static
condition. The instability index of the direct signal has a
negligible difference with that of the reflection signal
from a metal plate; thus, a simple measurement of direct
signal on the ground surface is suggested for the evaluation
of the instability of a GPR system in field in the
future.},
Doi = {10.1109/LGRS.2018.2801827},
Key = {fds341157}
}
@article{fds341066,
Author = {Song, Z and Wang, W and Cai, G and Liu, QH},
Title = {Investigation of Optical Spectrum Properties of Hexagonal
Boron Nitride from Metal to Dielectric Transition},
Journal = {Plasmonics},
Volume = {13},
Number = {2},
Pages = {563-566},
Year = {2018},
Month = {April},
url = {http://dx.doi.org/10.1007/s11468-017-0544-y},
Abstract = {Hexagonal boron nitride as a natural hyperbolic material has
attracted lots of attention recently. Here, we investigate
numerically the optical spectrum properties of hexagonal
boron nitride from the perspective of optical transition.
After careful data analysis, hexagonal boron nitride at the
epsilon-near-zero point of permittivity either turns from a
hyperbolic material to an effective dielectric for
transverse magnetic-polarized wave or from an effective
metal to an effective dielectric for transverse
electric-polarized wave. The results in this work may pave
the way for potential applications of hexagonal boron
nitride in the field of metamaterials.},
Doi = {10.1007/s11468-017-0544-y},
Key = {fds341066}
}
@article{fds341067,
Author = {Hu, Y and Fang, Y and LaBrecque, D and Ahmadian, M and Liu,
QH},
Title = {Reconstruction of high-contrast proppant in hydraulic
fractures with galvanic measurements},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {4},
Pages = {2066-2073},
Year = {2018},
Month = {April},
url = {http://dx.doi.org/10.1109/TGRS.2017.2773080},
Abstract = {Hydraulic fracturing is a technique to fracture rocks by
pumping high-pressure fluid into a segment of a well. The
created fractures help to release a hydrocarbon resource
such as oil or natural gas from the rock. A group of
small-scaled fracturing field tests are performed by the
Advanced Energy Consortium to investigate the feasibility of
using the galvanic electromagnetic (EM) method to map
fractures. The injected proppants are designed with high EM
contrasts (e.g., conductivity and permittivity) to generate
detectable signals at electrode-type sensors. To map the
created fractures, an efficient 3-D EM inversion method is
introduced to simultaneously reconstruct conductivity and
permittivity profiles in fractures. First, to test the
capability of the inversion solver and the designed
experimental setting for successful fracture mapping, the
noise-polluted synthetic data are used to reconstruct the
fracture on a theoretical model. It shows that the designed
experimental setting can be used to map the fracture and the
inversion solver is able to reconstruct the fracture in both
conductivity and permittivity. The inversion method is then
applied to two hydraulic fracturing field tests with
injected high-contrast proppants, Loresco coke breeze and
steel shot. The fracture conductivity and permittivity are
reconstructed based on the voltage signals difference
between the postfracturing and prefracturing data. The
reconstructed fracture profiles are compared with the coring
samplings to show the reliability of the inversion results.
Their good agreement demonstrates that the experimental
setting and the galvanic inverse solver are able to estimate
the fracture size and location reliably.},
Doi = {10.1109/TGRS.2017.2773080},
Key = {fds341067}
}
@article{fds340803,
Author = {Zhan, Q and Sun, Q and Zhuang, M and Mao, Y and Ren, Q and Fang, Y and Huang,
WF and Liu, QH},
Title = {A new upwind flux for a jump boundary condition applied to
3D viscous fracture modeling},
Journal = {Computer Methods in Applied Mechanics and
Engineering},
Volume = {331},
Pages = {456-473},
Publisher = {Elsevier BV},
Year = {2018},
Month = {April},
url = {http://dx.doi.org/10.1016/j.cma.2017.11.002},
Abstract = {We present a discontinuous Galerkin (DG) algorithm with
nonconformal meshes to simulate 3D elastic wave propagation
in heterogeneous media with arbitrary discrete fractures. In
our method, the fractures are not limited to be planar,
single, and lossless, but can be curved, intersecting, and
viscous. In contrast to the exact volumetric modeling for
the extremely thin layer, explicitly treating an individual
fracture as a geometry surface (i.e., an imperfect contact
interface) requires the jump condition for
displacement/velocity, but the continuity of traction vector
on the fracture interface. A new upwind flux is proposed to
weakly impose this jump boundary condition in the DG
framework. This flux guarantees the stability and accuracy
of the DG schemes to model arbitrary fractures. Unlike
conventional Riemann solvers applied to continuous media,
this solution involves an evolutionary update on the Godunov
states. Besides this, no extra computational cost is added.
In addition, we can extend the fracture interface into a
perfectly matched layer to mimic an infinitely large
fracture. Quantitative comparisons of the waveforms between
our algorithm and an independent finite element code
demonstrate the accuracy and efficiency of our
algorithm.},
Doi = {10.1016/j.cma.2017.11.002},
Key = {fds340803}
}
@article{fds341158,
Author = {Xu, KD and Li, M and Liu, Y and Yang, Y and Liu, QH},
Title = {Design of Triplexer Using E-Stub-Loaded Composite
Right-/Left-Handed Resonators and Quasi-Lumped Impedance
Matching Network},
Journal = {Ieee Access},
Volume = {6},
Pages = {18814-18821},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1109/ACCESS.2018.2819641},
Abstract = {A compact triplexer based on E-stub-loaded composite
right-/left-handed (ESL-CRLH) resonators with quasi-lumped
impedance matching network is presented in this paper. The
equivalent circuit model of the ESL-CRLH resonator is
presented first and its left-/right-handed
capacitance/inductance elements are fully derived. Then, a
quasi-lumped impedance matching circuit is designed to
connect the three ESL-CRLH resonator based filter channels
for the triplexer construction. Finally, the designed
triplexer obtains high isolations among the ports and low
in-band insertion losses of the three filter channels
centered at 1.86, 2.41, and 3.25 GHz, of which a
miniaturized layout has been realized. Good agreement
between the simulated and measured results can be observed
to validate the design idea.},
Doi = {10.1109/ACCESS.2018.2819641},
Key = {fds341158}
}
@article{fds341159,
Author = {Ma, Y and Gong, X and He, B and Li, X and Cao, D and Li, J and Xiong, Q and Chen,
Q and Chen, BH and Liu, QH},
Title = {On the quantification of the dissolved hydroxyl radicals in
the plasma-liquid system using the molecular probe
method},
Journal = {Journal of Physics D: Applied Physics},
Volume = {51},
Number = {15},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1088/1361-6463/aab379},
Abstract = {Hydroxyl (OH) radical is one of the most important reactive
species produced by plasma-liquid interactions, and the OH
in liquid phase (dissolved OH radical, OHdis) takes effect
in many plasma-based applications due to its high
reactivity. Therefore, the quantification of the OHdis in a
plasma-liquid system is of great importance, and a molecular
probe method usually used for the OHdis detection might be
applied. Herein, we investigate the validity of using the
molecular probe method to estimate the [OHdis] in the
plasma-liquid system. Dimethyl sulfoxide is used as the
molecular probe to estimate the [OHdis] in an air
plasma-liquid system, and usually the estimation of [OHdis]
is deduced by quantifying the OHdis-induced derivative, the
formaldehyde (HCHO). The analysis indicates that the true
concentration of the OHdis should be estimated from the sum
of three terms: the formed HCHO, the existing OH scavengers,
and the H2O2 formed from the OHdis. The results show that
the measured [HCHO] needs to be corrected since the HCHO
consumption is not negligible in the plasma-liquid system.
We conclude from the results and the analysis that the
molecular probe method generally underestimates the [OHdis]
in the plasma-liquid system. If one wants to obtain the true
concentration of the OHdis in the plasma-liquid system, one
needs to know the consumption behavior of the OHdis-induced
derivatives, the information of the OH scavengers (such as
hydrated electron, atomic hydrogen besides the molecular
probe), and also the knowledge of the H2O2 formed from the
OHdis.},
Doi = {10.1088/1361-6463/aab379},
Key = {fds341159}
}
@article{fds340804,
Author = {Lin, X and Wen, J and Tang, Y and Ma, M and You, D and Dou, B and Wu, X and Zhu,
X and Xiao, Q and Liu, Q},
Title = {A web-based land surface remote sensing products validation
system (LAPVAS): application to albedo product},
Journal = {International Journal of Digital Earth},
Volume = {11},
Number = {3},
Pages = {308-328},
Publisher = {Informa UK Limited},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1080/17538947.2017.1320593},
Abstract = {Quantitative remote sensing product (QRSP) validation is a
complex process to assess the accuracy and uncertainty
independently using reference data with multiple land cover
types and long-time series. A web-based system named as LAnd
surface remote sensing Product VAlidation system (LAPVAS) is
described in this paper, which is used to implement the
QRSPs validation process automatically. The LAPAVS has two
subsystems, the Validation Databases Subsystem and the
Accuracy Evaluation Subsystem. Three functions have been
implemented by the two subsystems for a comprehensive QRSP
validation: (1) a standardized processing of reference data
and storage of these data in validation databases; (2) a
consistent and comprehensive validation procedure to assess
the QRSPs’ accuracy and uncertainty; and (3) a visual
process customization tool with which the users can register
new validation data, host new reference data, and readjust
the validation workflows for the QRSP accuracy assessment.
In LAPVAS, more than 100 GB of reference data warehoused in
validation databases for 13 types of QRSPs’ validation.
One of the key QRSPs, land surface albedo, is selected as an
example to illustrate the application of LAPVAS. It is
demonstrated that the LAPVAS has a good performance in the
land surface remote sensing product validation.},
Doi = {10.1080/17538947.2017.1320593},
Key = {fds340804}
}
@article{fds341160,
Author = {Zhuang, M and Zhou, J and Wei, S and Liu, QH},
Title = {The rotated Cartesian coordinate method to remove the axial
singularity of cylindrical coordinates in finite-difference
schemes for elastic and viscoelastic waves},
Journal = {Geophysical Prospecting},
Volume = {66},
Pages = {27-39},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1111/1365-2478.12572},
Abstract = {When modelling the propagation of 3D non-axisymmetric
elastic and viscoelastic waves in cylindrical coordinates
using the finite-difference time-domain method, a
mathematical singularity occurs due to the presence of 1/r
terms in the elastic and viscoelastic wave equations. For
many years, this issue has been impeding the accurate
numerical solution near the axis. In this work, we propose a
simple but effective method for the treatment of this
numerical singularity problem. By rotating the Cartesian
coordinate system around the z-axis in cylindrical
coordinates, the numerical singularity problems in both 2D
and 3D cylindrical coordinates can be removed. This
algorithm has three advantages over the conventional
treatment techniques: (i) the excitation source can be
directly loaded at r=0, (ii) the central difference scheme
with second-order accuracy is maintained, and (iii) the
stability condition at the axis is consistent with the
finite-difference time-domain in Cartesian coordinates. This
method is verified by several 3D numerical examples. Results
show that the rotating the Cartesian coordinate method is
accurate and stable at the singularity axis. The improved
finite-difference time-domain algorithm is also applied to
sonic logging simulations in non-axisymmetric formations and
sources.},
Doi = {10.1111/1365-2478.12572},
Key = {fds341160}
}
@article{fds341161,
Author = {Deng, C and Luo, M and Yuan, M and Zhao, B and Zhuang, M and Liu,
QH},
Title = {The Auxiliary Differential Equations Perfectly Matched
Layers Based on the Hybrid SETD and PSTD Algorithms for
Acoustic Waves},
Journal = {Journal of Theoretical and Computational
Acoustics},
Volume = {26},
Number = {1},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1142/S2591728517500311},
Abstract = {The perfectly matched layer (PML) absorbing boundary
condition has been proven to absorb body waves and surface
waves very efficiently at non-grazing incidence. However,
the traditional PML would generate large spurious
reflections at grazing incidence, for example, when the
sources are located near the truncating boundary and the
receivers are at a large offset. In this paper, a new PML
implementation is presented for the boundary truncation in
three-dimensional spectral element time domain (SETD) for
solving acoustic wave equations. This method utilizes
pseudospectral time-domain (PSTD) method to solve
first-order auxiliary differential equations (ADEs), which
is more straightforward than that in the classical FEM
framework.},
Doi = {10.1142/S2591728517500311},
Key = {fds341161}
}
@article{fds341162,
Author = {Xie, J and Zhuang, M and Guo, Z and Liu, H and Liu, QH},
Title = {Reverse Time Migration of Elastic Waves Using the
Pseudospectral Time-Domain Method},
Journal = {Journal of Theoretical and Computational
Acoustics},
Volume = {26},
Number = {1},
Year = {2018},
Month = {March},
url = {http://dx.doi.org/10.1142/S2591728517500335},
Abstract = {Reverse time migration (RTM), especially that for elastic
waves, consumes massive computation resources which limit
its wide applications in industry. We suggest to use the
pseudospectral time-domain (PSTD) method in elastic wave
RTM. RTM using PSTD can significantly reduce the
computational requirements compared with RTM using the
traditional finite difference time domain method (FDTD). In
addition to the advantage of low sampling rate with high
accuracy, the PSTD method also eliminates the periodicity
(or wraparound) limitation caused by fast Fourier transform
in the conventional pseudospectral method. To achieve
accurate results, the PSTD method needs only about half the
spatial sampling rate of the twelfth-order FDTD method.
Thus, the PSTD method can save up to 87.5% storage memory
and 90% computation time over the twelfth-order FDTD method.
We implement RTM using PSTD for elastic wave equations and
accelerate it by Open Multi-Processing technology. To keep
the computational load balance in parallel computation, we
design a new PML layout which merges the PML in both ends of
an axis together. The efficiency and imaging quality of the
proposed RTM is verified by imaging on 2D and 3D
models.},
Doi = {10.1142/S2591728517500335},
Key = {fds341162}
}
@article{fds340949,
Author = {Chen, H and Zhou, Y and Zhou, M and Xu, L and Liu, QH},
Title = {Perfect Undetectable Acoustic Device from Fabry-Pérot
Resonances},
Journal = {Physical Review Applied},
Volume = {9},
Number = {2},
Year = {2018},
Month = {February},
url = {http://dx.doi.org/10.1103/PhysRevApplied.9.024014},
Abstract = {Transformation acoustics is a method to design novel
acoustic devices, while the complexity of the material
parameters hinders its progress. In this paper, we
analytically present a three-dimensional perfect
undetectable acoustic device from Fabry-Pérot resonances
and confirm its functionality from Mie theory. Such a
mechanism goes beyond the traditional transformation
acoustics. In addition, such a reduced version can be
realized by holey-structured metamaterials. Our theory paves
a way to the implementation of three-dimensional
transformation acoustic devices.},
Doi = {10.1103/PhysRevApplied.9.024014},
Key = {fds340949}
}
@article{fds340805,
Author = {Hong, D and Yu, Y and Ren, Y and Huang, WF and Liu, QH},
Title = {Compact pseudoanalytic formulations of coaxial coil antennas
in a cylindrically multilayered medium for well-logging
applications},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {12},
Number = {2},
Pages = {217-223},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2018},
Month = {February},
url = {http://dx.doi.org/10.1049/iet-map.2017.0471},
Abstract = {In this study, the authors present a set of compact and
no-overflow formulations to calculate the response of
logging tools with coaxial coil antennas in a concentric
cylindrically multilayered formation. It can be applied to
fast forward computation and the inverse problem for
electromagnetic well-logging. The tool mandrel can be
cylindrically multilayered, and the electrical parameters of
each layer are arbitrary. In contrast with previous
formulations, they adopt the novel reflection and
transmission coefficients in the authors' formulations so
that the notorious overflow problem for numerical
computation can be obviated. Numerical results in comparison
with those from other approaches have demonstrated the
validity and stability of their new formulations.},
Doi = {10.1049/iet-map.2017.0471},
Key = {fds340805}
}
@article{fds331499,
Author = {Li, S and Hong, R and Liu, N and Zhang, J and Chen, L and Zhang, Y and Yu, Z and Liu, QH},
Title = {Three-dimensional MR reconstruction of high-contrast
magnetic susceptibility by the variational born iterative
method based on the magnetic field volume integral
equation.},
Journal = {Magnetic Resonance in Medicine},
Volume = {79},
Number = {2},
Pages = {923-932},
Year = {2018},
Month = {February},
url = {http://dx.doi.org/10.1002/mrm.26760},
Abstract = {<h4>Purpose</h4>To provide high-quality and high-contrast
magnetic susceptibility mapping, a 3D MR reconstruction
method for magnetic susceptibility based on the magnetic
field volume integral equation with the variational Born
iterative method (VBIM) is developed.<h4>Methods</h4>Three-dimensional
magnetic susceptibility is reconstructed from the positive
rotating magnetic field component H1+ of the radiofrequency
field acquired by B<sub>1</sub> mapping. The stabilized
biconjugate gradient fast Fourier transform (BCGS-FFT)
method is implemented in the forward problem to solve for
the magnetic field, and the conjugate gradient fast Fourier
transform method is implemented in the inverse problem to
reconstruct the magnetic susceptibility distribution.<h4>Results</h4>Numerical
results demonstrated that good effectiveness and high
accuracy can be achieved for both the forward solver of the
stabilized biconjugate gradient fast Fourier transform
method and the inverse solver of the VBIM method. The method
proved to be robust under noise contamination. Moreover, the
magnetic susceptibilities with much higher contrasts than
that of the non-full wave methods can also be efficiently
reconstructed.<h4>Conclusions</h4>The proposed method can
reconstruct the magnetic susceptibility of not only human
head, but also other human tissues or materials such as
magnetic contrast agents with high magnetic
susceptibilities. It has promising applications in
high-contrast magnetic susceptibility mapping. Magn Reson
Med 79:923-932, 2018. © 2017 International Society for
Magnetic Resonance in Medicine.},
Doi = {10.1002/mrm.26760},
Key = {fds331499}
}
@article{fds341163,
Author = {Zhan, Q and Ren, Q and Zhuang, M and Sun, Q and Liu,
QH},
Title = {An exact Riemann solver for wave propagation in arbitrary
anisotropic elastic media with fluid coupling},
Journal = {Computer Methods in Applied Mechanics and
Engineering},
Volume = {329},
Pages = {24-39},
Year = {2018},
Month = {February},
url = {http://dx.doi.org/10.1016/j.cma.2017.09.007},
Abstract = {We present a nonconformal mesh discontinuous Galerkin
pseudospectral time domain algorithm for arbitrary
anisotropic elastic/acoustic wave propagation problems. An
exact Riemann solver is compactly derived to resolve the
accurate coupling of multiple domains in the discontinuous
Galerkin framework, including heterogeneous anisotropic
solid–solid, acoustic–acoustic, and anisotropic
solid–fluid interactions. We simplify the eigenvalue
problem in the Riemann solution from the rank of 9 to 3, and
introduce the generalized wave impedance with more physical
insight. Validations and verifications with independent
codes and analytical solutions illustrate the accuracy,
flexibility, and stability of our algorithm.},
Doi = {10.1016/j.cma.2017.09.007},
Key = {fds341163}
}
@article{fds340806,
Author = {Liang, B and Qiu, C and Han, F and Zhu, C and Liu, N and Liu, H and Liu, F and Fang, G and Liu, QH},
Title = {A New Inversion Method Based on Distorted Born Iterative
Method for Grounded Electrical Source Airborne Transient
Electromagnetics},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {2},
Pages = {877-887},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {February},
url = {http://dx.doi.org/10.1109/TGRS.2017.2756086},
Abstract = {A new iterative inversion algorithm is proposed to
reconstruct the electrical conductivity profile in a
stratified underground medium for the grounded electrical
source airborne transient electromagnetic (GREATEM) system.
In forward modeling, we simplify the mathematical
expressions of the magnetic fields generated by a finite
line source in the layered ground to semianalytical forms in
order to save the computation time. The Fréchet derivative
is derived for the electromagnetic response at the receivers
due to a small perturbation of the conductivity in a certain
layer underground. The initial expression of the Fréchet
derivative has an expensive triple integral and contains the
Bessel function in the integrand. It is simplified by
partially eliminating the integration along the source line
and deriving the analytical expression for the integration
in the vertical direction inside the perturbed layer. In the
inverse solution, we use the distorted Born iterative method
(DBIM). This is the first time that the DBIM is applied to
data measured by the GREATEM system. Besides, the forward
and inverse procedures are carried out in the frequency
domain and based on the Fréchet derivative of a line
source. We demonstrate the validity of our forward model,
Fréchet derivative, inverse model, and the precision as
well as robustness of the inversion algorithm through
numerical computation and comparisons. Finally, we apply the
inversion algorithm to the measured data and compare the
retrieved conductivity to the actual drilling
data.},
Doi = {10.1109/TGRS.2017.2756086},
Key = {fds340806}
}
@article{fds341164,
Author = {Zhan, Q and Zhang, R and Baker, J and Hansen, H and Liu,
QH},
Title = {Mapping the foam-induced dielectric anisotropy for
high-speed cables},
Journal = {2017 Ieee Electrical Design of Advanced Packaging and
Systems Symposium, Edaps 2017},
Volume = {2018-January},
Pages = {1-9},
Year = {2018},
Month = {January},
ISBN = {9781538612385},
url = {http://dx.doi.org/10.1109/EDAPS.2017.8277039},
Abstract = {Foaming the expanded polyethylene (PE) is a prevailing way
to lower the dielectric constants and dissipation factors of
insulators in modern communication high-speed cables. The
porosity and elongated cell shapes impose significant
effects on the dielectric properties of PE. However, a
theoretical study is lacking. This work proposes an
effective way to predict the dielectric parameters of foamed
PE. Unlike directly generating the extremely dense meshes
for the randomly distributed pores, which is usually
computationally intractable, we apply an electrodynamics
homogenization method to obtain the equivalent anisotropic
model for the complex foamed insulators. It is shown that
the predicted values are amenable to the experimentally
measured data.},
Doi = {10.1109/EDAPS.2017.8277039},
Key = {fds341164}
}
@article{fds340831,
Author = {Xu, KD and Xu, H and Liu, Y and Li, J and Liu, QH},
Title = {Microstrip Patch Antennas with Multiple Parasitic Patches
and Shorting Vias for Bandwidth Enhancement},
Journal = {Ieee Access},
Volume = {6},
Pages = {11624-11633},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1109/ACCESS.2018.2794962},
Abstract = {Two novel microstrip patch antennas with multiple parasitic
patches and shorting vias have been presented for the
bandwidth enhancement. Based on the conventional triangular
patch antenna, two more resonances can be obtained with the
introduction of multiple parasitic patches, and
consequently, the antenna bandwidth can be broadened.
Parametric analysis of the patches has been studied for the
verification of bandwidth enhancement. An example of the
proposed antenna with multiple parasitic patches is
designed, fabricated, and tested. The measured bandwidth
with vert S11}vert < -10 dB ranges from 5.46 to 6.27 GHz
(13.8%), and good far-field radiation patterns can be
obtained within the frequency band. In addition, two
shorting vias are inserted into the above proposed antenna
to decrease the input impedance, resulting in further
bandwidth enhancement of the antenna. This antenna is
fabricated and tested as well, which achieves a measured
10-dB impedance bandwidth of 17.4% from 5.5 to 6.55
GHz.},
Doi = {10.1109/ACCESS.2018.2794962},
Key = {fds340831}
}
@article{fds341165,
Author = {Lan, T and Liu, H and Liu, N and Li, J and Han, F and Liu,
QH},
Title = {Joint inversion of electromagnetic and seismic data based on
structural constraints using variational born iteration
method},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {1},
Pages = {436-445},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1109/TGRS.2017.2749240},
Abstract = {An efficient 2-D joint full-waveform inversion method for
electromagnetic and seismic data in a layered medium
background is developed. The joint inversion method based on
the integral equation (IE) method is first proposed in this
paper. In forward computation, the IE method is employed,
which usually has smaller discretized computation domain and
less cumulative error compared with the finite-difference
method. In addition, fast Fourier transform is used to
accelerate the convolution between Green's functions and
induced sources due to the shift invariance property of the
layered Green's functions in the horizontal direction. In
the inversion model, the crossgradient function is
incorporated into the cost function of the separate
inversion to enforce the structure similarity between
electric conductivity and seismic-wave velocity. We use the
improved variational Born iteration method and two different
iteration strategies to minimize the cost function and
reconstruct the contrasts. Several typical models in
geophysical applications are used to validate our joint
inversion method, and the numerical simulation results show
that joint inversion can improve the inversion results when
compared with those from the separate inversion.},
Doi = {10.1109/TGRS.2017.2749240},
Key = {fds341165}
}
@article{fds341166,
Author = {Sun, Q and Zhang, R and Zhan, Q and Liu, QH},
Title = {A Novel Coupling Algorithm for Perfectly Matched Layer with
Wave Equation-Based Discontinuous Galerkin Time-Domain
Method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {66},
Number = {1},
Pages = {255-261},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1109/TAP.2017.2769132},
Abstract = {The second-order wave equation-based discontinuous Galerkin
time-domain (DGTD) methods typically employ the first-order
absorbing boundary condition for modeling open problems. To
improve the modeling accuracy, this paper proposes a novel
coupling algorithm of the well-posed perfectly matched layer
(PML) for wave equation-based DGTD methods. Based on the
domain decomposition technique, the proposed coupling
algorithm divides the computational domain into two regions,
that is, the physical and PML regions, whose meshes can be
nonconformal with each other. Instead of introducing time
convolution terms, the new coupling scheme is implemented
through employing different DGTD frameworks for the two
regions. Specifically, the physical region employs the wave
equation-based DGTD framework, while the PML region employs
the first-order Maxwell's curl equations-based DGTD
framework. To facilitate modeling of electrically small
problems, the implicit Newmark-beta time integration is used
for the physical region. To conveniently couple with the
physical region, the implicit Crank-Nicolson algorithm is
used for the PML region. Numerical results are shown to
examine the accuracy and efficiency of the proposed coupling
algorithm for modeling electrically small
problems.},
Doi = {10.1109/TAP.2017.2769132},
Key = {fds341166}
}
@article{fds341167,
Author = {Dai, J and Fang, Y and Zhou, J and Liu, QH},
Title = {Analysis of electromagnetic induction for hydraulic fracture
diagnostics in open and cased boreholes},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {56},
Number = {1},
Pages = {264-271},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1109/TGRS.2017.2746346},
Abstract = {In this paper, the sensitivity and detectability of an
electromagnetic induction tool for hydraulic fracture
detection are analyzed by calculating the electromagnetic
response from an orthogonal transverse fracture (OTF) in an
open or cased borehole using the improved numerical mode
matching method. The OTF is modeled as a slim circular disk,
which is axially symmetric with respect to the borehole axis
and filled with a conductive or magnetic proppant. The
feasibility of the induction tool for fracture diagnostics
was validated via scaled-down experimental measurements. We
then quantitatively analyze the induction response
sensitivity to different proppant parameters, such as
conductivity and permeability, to evaluate the effectiveness
of the induction logging tool for fracture detection. The
analysis reveals that the short-spaced receiver can
accurately locate the fracture position and distinguish
small-sized fractures, while the long-spaced receiver can
differentiate fractures with large dimension. Casings with
different thicknesses, conductivities, and permeabilities
are modeled together with the fracture to investigate their
effects in fracture detection. Finally, the application of
the induction tool to a fracture network is
evaluated.},
Doi = {10.1109/TGRS.2017.2746346},
Key = {fds341167}
}
@article{fds340807,
Author = {He, B and Gong, X and Wang, X and Li, J and Xiong, Q and Chen, Q and Liu,
QH},
Title = {What are the effective reactants in the plasma-induced
wastewater treatment?},
Journal = {Journal of the Electrochemical Society},
Volume = {165},
Number = {10},
Pages = {E454-E459},
Publisher = {The Electrochemical Society},
Year = {2018},
Month = {January},
url = {http://dx.doi.org/10.1149/2.0241810jes},
Abstract = {We perform a series of experiments in a plasma-liquid
system, aiming to explore in real time the change of a
synthetic wastewater (methyl orange, MO) under an
atmospheric pressure DC plasma exposure. The results
indicate that the short-lived hydroxyl radicals generated
from the plasma-liquid interactions are the predominant
reactants in the MO molecules decomposition, while the
long-lived species such as the plasma-induced hydrogen
peroxide (H2O2) are ineffective. Nevertheless, the
plasma-generated H2O2 can contribute to the MO decomposition
by producing hydroxyl radicals from reacting with Fe2+
(Fenton's reaction) or by producing peroxynitrite from
reacting with NO2-.Moreover, the MO decomposition rate in
the case of liquid cathode is found to be significantly
faster than that in the case of liquid anode.},
Doi = {10.1149/2.0241810jes},
Key = {fds340807}
}
@article{fds341169,
Author = {Zheng, J and Liu, H and Liu, QH},
Title = {Parameterized Centroid Frequency-Chirp Rate Distribution for
LFM Signal Analysis and Mechanisms of Constant Delay
Introduction},
Journal = {Ieee Transactions on Signal Processing},
Volume = {65},
Number = {24},
Pages = {6435-6447},
Year = {2017},
Month = {December},
url = {http://dx.doi.org/10.1109/TSP.2017.2755604},
Abstract = {This paper presents an extension of the integrated
time-chirp rate analysis technique, known as the
parameterized centroid frequency-chirp rate distribution
(PCFCRD), for noisy multicomponent linear frequency
modulated signals analysis. The PCFCRD is based on a newly
defined correlation function and its auto term accumulation
is two-dimensionally coherent. The principle, cross term
characteristic, implementation, properties, parameter
selection criterion, antinoise performance, and estimation
accuracy are analyzed for the PCFCRD. In this paper,
comparisons with the coherently integrated cubic phase
function, maximum likelihood method, and Lv's distribution
are performed. With mathematic analyses and numerical
simulations, we demonstrate that the PCFCRD outperforms
these three representative counterparts. Further, by
combining with analyses of the PCFCRD, several unclear
mechanisms of the constant delay introduction are
mathematically interpreted, especially quantitative
influences on the chirp rate resolution and theoretical
antinoise performance.},
Doi = {10.1109/TSP.2017.2755604},
Key = {fds341169}
}
@article{fds341170,
Author = {Liao, Y and Liu, QH},
Title = {Modified Chirp Scaling Algorithm for Circular Trace Scanning
Synthetic Aperture Radar},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {12},
Pages = {7081-7091},
Year = {2017},
Month = {December},
url = {http://dx.doi.org/10.1109/TGRS.2017.2740063},
Abstract = {For circular trace scanning synthetic aperture radar
(CTSSAR) with a circular track, the conventional hyperbolic
equation becomes inadequate to express the range history of
a point target accurately, and when it comes to the wide
swath observation and imaging, the range variance makes it
even harder to focus the target on the edge of the scene.
Thus, an expression with high-order terms is needed to
approximate the range history and the range variance should
also be considered in the imaging algorithm. In this paper,
based on the method of series reversion, a fourth-order
approximated range model is established for the CTSSAR
processing and the 2-D spectrum is derived for the echo
signal in CTSSAR with circular trajectory. At the same time,
in order to deal with the range-variant range cell migration
problem in large-area CTSSAR imaging, a modified chirp
scaling algorithm is proposed to realize precise wide swath
CTSSAR focusing. Experiments and analyses are performed to
validate the effectiveness of the proposed
algorithm.},
Doi = {10.1109/TGRS.2017.2740063},
Key = {fds341170}
}
@article{fds341171,
Author = {Liu, Y and Zhao, Z and Zhu, X and Nie, Z and Liu, QH},
Title = {A CSEB subspace-based optimization method for reconstruction
of uniaxial anisotropic objects},
Journal = {Progress in Electromagnetics Research Symposium},
Volume = {2017-November},
Pages = {93-98},
Year = {2017},
Month = {November},
ISBN = {9781538612118},
url = {http://dx.doi.org/10.1109/PIERS-FALL.2017.8293116},
Abstract = {This paper deals with the image reconstruction from measured
scattered field data for 2D uniaxial anisotropic objects.
There are two main contributions of this work. First, the
CSEB model was designed to deal with the reconstruction of
isotropic objects. In this paper, the CSEB model is modified
for the inverse problem of uniaxial anisotropic case.Second,
it is demonstrated by the numerical examples that the degree
of nonlinearity of the problem is decreased compared with
the original model, and this outcome is the same as it is
shown in the isotropic case. Third, subspace techniques are
introduced in the framework of CSEB model. Numerical
examples demonstrate the effectiveness of the CSEB-SOM for
reconstruction of uniaxial anisotropic objects.},
Doi = {10.1109/PIERS-FALL.2017.8293116},
Key = {fds341171}
}
@article{fds341172,
Author = {Liu, H and Deng, Z and Han, F and Xia, Y and Liu, QH and Sato,
M},
Title = {Time-frequency analysis of air-coupled GPR data for
identification of delamination between pavement
layers},
Journal = {Construction and Building Materials},
Volume = {154},
Pages = {1207-1215},
Year = {2017},
Month = {November},
url = {http://dx.doi.org/10.1016/j.conbuildmat.2017.06.132},
Abstract = {Identification of delamination in pavement layers using
ground penetrating radar (GPR) is still challenging due to
its limited range resolution. This paper investigates the
characteristics of the composite reflection from the
air-filled delamination between pavement layers by
time-frequency analysis. We firstly simulated GPR data from
an asphalt pavement model with an embedded air gap of
different thicknesses by the Green's function method. Then
we conducted a laboratory experiment on a delaminated
asphalt pavement model. Both the numerical and laboratory
experiment results demonstrate that both the peak
instantaneous frequency and its amplitude are sensitive to
the variation of the air gap thickness. When the thickness
of the air gap is smaller than a quarter of the dominant
wavelength, the peak instantaneous frequency of the
composite reflection is higher than that of the normal
interface reflection. We conclude that we can identify the
delamination from the overall rise in the peak instantaneous
frequency.},
Doi = {10.1016/j.conbuildmat.2017.06.132},
Key = {fds341172}
}
@article{fds341173,
Author = {Sun, Q and Zhang, R and Zhan, Q and Liu, QH},
Title = {Multiscale Hydraulic Fracture Modeling with Discontinuous
Galerkin Frequency-Domain Method and Impedance Transition
Boundary Condition},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {11},
Pages = {6566-6573},
Year = {2017},
Month = {November},
url = {http://dx.doi.org/10.1109/TGRS.2017.2730039},
Abstract = {To facilitate the detection of hydraulic fractures by
electromagnetic survey, a discontinuous Galerkin
frequency-domain (DGFD) method is introduced in this paper
to efficiently model the fracture responses under
complicated geophysical environments. In the proposed DGFD
method, the computational domain can be split into multiple
subdomains with nonconformal meshes. The Riemann solver
(upwind flux) is introduced to evaluate the numerical flux.
The impedance transition boundary condition (ITBC) is
employed to facilitate fracture modeling by approximating
fractures as surfaces. Numerical results show that the ITBC
works well for different fracture conductivities, dipping
angles, operation frequencies, as well as different sources.
For both small- and large-scale fractures, it also shows
good agreement with the references. The responses of
fractures increase as their conductivities become larger.
Large dipping angles can cause spikes on the responses in a
borehole. For a magnetic source, higher operation
frequencies can enhance the signal level, while for an
electric source, the sensitivity to frequency is small. When
no borehole is considered, the responses due to an electric
source are in general larger than those due to a magnetic
one. However, when a borehole with conductive mud is
included, the responses can be reversed for the electric and
magnetic sources. For multiple fractures outside a cased
borehole, the signal level of an electric source is
significantly reduced, while that of a magnetic source
remains at a similar level compared with the scenario
without a casing. With the proposed technique, multiscale
modeling of hydraulic fractures in complicated geophysical
environments becomes possible.},
Doi = {10.1109/TGRS.2017.2730039},
Key = {fds341173}
}
@article{fds340810,
Author = {Zhou, Y and Zhuang, M and Shi, L and Cai, G and Liu, N and Liu,
QH},
Title = {Spectral-Element Method with Divergence-Free Constraint for
2.5-D Marine CSEM Hydrocarbon Exploration},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {14},
Number = {11},
Pages = {1973-1977},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {November},
url = {http://dx.doi.org/10.1109/LGRS.2017.2743781},
Abstract = {Rapid simulations of large-scale low-frequency subsurface
electromagnetic measurements are still a challenge because
of the low-frequency breakdown phenomenon that makes the
system matrix extremely poor-conditioned. Hence, significant
attention has been paid to accelerate the numerical
algorithms for Maxwell's equations in both integral and
partial differential forms. In this letter, we develop a
novel 2.5-D method to overcome the low-frequency breakdown
problem by using the mixed spectral element method with the
divergence-free constraint and apply it to solve the
marine-controlled-source electromagnetic systems. By
imposing the divergence-free constraint, the proposed method
considers the law of conservation of charges, unlike the
conventional governing equation for these problems.
Therefore, at low frequencies, the Gauss law guarantees the
stability of the solution, and we can obtain a
well-conditioned system matrix even as the frequency
approaches zero. Several numerical experiments show that the
proposed method is well suited for solving low-frequency
electromagnetic problems.},
Doi = {10.1109/LGRS.2017.2743781},
Key = {fds340810}
}
@article{fds341174,
Author = {Zhang, M and Chen, D and Ye, L and Liu, QH},
Title = {Wideband design of sub-arrays in a Q-band
partially-corporate fed waveguide slot array},
Journal = {2017 Ieee Antennas and Propagation Society International
Symposium, Proceedings},
Volume = {2017-January},
Pages = {619-620},
Year = {2017},
Month = {October},
ISBN = {9781538632840},
url = {http://dx.doi.org/10.1109/APUSNCURSINRSM.2017.8072352},
Abstract = {A mesh network composed of the 40 GHz-band Fixed Wireless
Access system is very essential to realize outdoor backhauls
as well as fronthauls for 5G network. A 20×20-element
antenna has been successfully developed in the Q-band. The
partially-corporate feeding structure is adopted to divide
the whole antenna into 2×2 sub-arrays for wideband
operation. To further enhance the bandwidth of input
matching, standing-wave fed sub-arrays of both radiating and
coupling slots are investigated. By introducing the
overloading technique, the bandwidth is improved from 3.1%
to 7.7% especially for the sub-array of radiating slots. It
is very promising to realize a broadband 20×20-element
waveguide slot array by combining those redesigned
sub-arrays.},
Doi = {10.1109/APUSNCURSINRSM.2017.8072352},
Key = {fds341174}
}
@article{fds341175,
Author = {Niu, J and Ren, Y and Liu, QH},
Title = {A hybrid perfectly matched layer - Spectral element boundary
integral method for periodic/ non-periodic
analyses},
Journal = {2017 Ieee Antennas and Propagation Society International
Symposium, Proceedings},
Volume = {2017-January},
Pages = {1345-1346},
Year = {2017},
Month = {October},
ISBN = {9781538632840},
url = {http://dx.doi.org/10.1109/APUSNCURSINRSM.2017.8072715},
Abstract = {A novel perfectly matched layer - spectral element boundary
integral (PML-SEBI) method is proposed for integrated
analysis of periodic and non-periodic structures in
stratified background. The proposed numerical scheme
hybridizes the perfectly matched layer and the surface
integral equations (SIE's) for lateral and top/bottom
boundaries, respectively. This hybrid method avoids the
singularity issues in dyadic layered medium Green's
function, while maximumly integrating the periodic and
non-periodic solvers together.},
Doi = {10.1109/APUSNCURSINRSM.2017.8072715},
Key = {fds341175}
}
@article{fds341176,
Author = {Niu, J and Ren, Y and Liu, QH},
Title = {Singularity extraction for periodic layered medium green's
function under matrix-friendly formulation},
Journal = {2017 Ieee Antennas and Propagation Society International
Symposium, Proceedings},
Volume = {2017-January},
Pages = {1351-1352},
Year = {2017},
Month = {October},
ISBN = {9781538632840},
url = {http://dx.doi.org/10.1109/APUSNCURSINRSM.2017.8072718},
Abstract = {A singularity extraction technique is proposed to calculate
the doubly periodic dyadic layered medium Green's function
(P-DLMGF). Contrast from the conventional singularity
subtraction method, the proposed approach starts from the
matrix-friendly formulation of P-DLMGF. By first
transferring the spatial derivatives from the P-DLMGF to the
testing and basis function, the singularity of the dual
summation kernel can be reduced by up to two order.
Asymptotic and add-back terms are then derived with
considerably improved feasibility.},
Doi = {10.1109/APUSNCURSINRSM.2017.8072718},
Key = {fds341176}
}
@article{fds333579,
Author = {Cai, QM and Zhao, YW and Zhang, ZP and Gu, L and Zheng, YT and Nie, ZP and Liu, QH},
Title = {Wideband frequency analysis using volume surface integral
equation and taylor series expansion},
Journal = {2017 Ieee Antennas and Propagation Society International
Symposium, Proceedings},
Volume = {2017-January},
Pages = {129-130},
Publisher = {IEEE},
Year = {2017},
Month = {October},
ISBN = {9781538632840},
url = {http://dx.doi.org/10.1109/APUSNCURSINRSM.2017.8072107},
Abstract = {This paper present a Galerkin-type method of moments (MoM)
solution of volume surface integral equation (VSIE) and
Taylor series expansion (TSE). This VSIE-TSE scheme is
developed for the wideband frequency analysis of composite
metallic and dielectric (CMD) structures. By expanding the
exponential of the Green's function into a Taylor series,
the impedance matrices can be efficiently calculated and
generated, when the frequency sweeping process. In
comparison with the conventional VSIE method, our scheme
requires much less computational time while the accuracy
remains at the same level. Several numerical examples are
presented to demonstrate the accuracy and efficiency of the
VSIE-TSE scheme.},
Doi = {10.1109/APUSNCURSINRSM.2017.8072107},
Key = {fds333579}
}
@article{fds341068,
Author = {You, P and Liu, Y and Chen, SL and Da, K and Li, W and Liu,
QH},
Title = {Synthesis of Unequally Spaced Linear Antenna Arrays with
Minimum Element Spacing Constraint by Alternating Convex
Optimization},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {3126-3130},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1109/LAWP.2017.2764069},
Abstract = {A novel method called alternating convex optimization is
presented to synthesize unequally spaced linear arrays with
minimum element spacing constraint. In this method, the
problem of synthesizing an unequally spaced array is
formulated as a sequence of alternating convex optimization
problems, and the excitation vector and auxiliary weighting
vector are alternately chosen as the optimization variables.
The minimum spacing constraint for considering the physical
element antenna size can be easily imposed in this
alternating optimization process. Two examples for
synthesizing unequally spaced linear arrays with focused and
shaped patterns are provided to validate the effectiveness
and advantages of the proposed method.},
Doi = {10.1109/LAWP.2017.2764069},
Key = {fds341068}
}
@article{fds341069,
Author = {He, B and Ma, Y and Gong, X and Long, Z and Li, J and Xiong, Q and Liu, H and Chen, Q and Zhang, X and Yang, S and Liu, QH},
Title = {Simultaneous quantification of aqueous peroxide, nitrate,
and nitrite during the plasma-liquid interactions by
derivative absorption spectrophotometry},
Journal = {Journal of Physics D: Applied Physics},
Volume = {50},
Number = {44},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1088/1361-6463/aa8819},
Abstract = {A derivative absorption spectroscopic method is used in situ
to simultaneously trace and quantify the aqueous peroxide
(H2O2), nitrate (NO-3) and nitrite (NO-2) generated during
plasma-liquid interactions. The results indicate that the
time evolutions of H2O2, and generated from the
plasma-liquid interactions strongly depend on the solution's
pH value, which varies with the plasma treatment. The
concentrations of aqueous H2O2, and increase independently
from each other during the plasma treatment when the
solution's pH value is higher than 3.0. However, when the
solution's pH value is less than 3.0, most of the aqueous
(∼71.5%) will exist in the form of molecular nitrous acid
since the pK a of nitrous acid is 3.4, the aqueous is mainly
formed from the reaction between H2O2 and as well as the
decomposition of molecular HNO2, which leads to a continuous
increase of concentration and an appearance of the maximum
concentrations of H2O2 and as the pH value of the solution
reaches 3.0.},
Doi = {10.1088/1361-6463/aa8819},
Key = {fds341069}
}
@article{fds341179,
Author = {Zhuo, J and Han, F and Liu, N and Ye, L and Liu, H and Liu,
QH},
Title = {Derivation and fast computation of dyadic green's functions
of magnetic vector potential for unbounded uniaxial
anisotropic media},
Journal = {Applied Computational Electromagnetics Society
Journal},
Volume = {32},
Number = {10},
Pages = {862-871},
Year = {2017},
Month = {October},
Abstract = {The dyadic Green's function of the magnetic vector-potential
A (DGFA) for unbounded uniaxial anisotropic media is
unavailable in literature but it is needed in numerical
computation. The equation of the DGFA was directly derived
from the Maxwell's equations. Through the Fourier transform
and the inverse Fourier transform, the triple integral form
of the DGFA in the spatial domain was obtained. And it was
finally simplified to Sommerfeld integrals. In order to
verify these formulas, we applied the singularity
subtraction technique to evaluate the Sommerfeld integrals
rapidly and compared the numerical results with the
analytical solutions for degenerated cases for the isotropic
unbounded media, as well as the simulated results from a
commercial finite element software for uniaxial anisotropic
unbounded media. Finally, the effect of the singularity
subtraction method was discussed.},
Key = {fds341179}
}
@article{fds341180,
Author = {Niu, J and Ren, Y and Liu, QH},
Title = {Spectral element boundary integral method with periodic
layered medium dyadic Green's function for multiscale
nano-optical scattering analysis.},
Journal = {Optics Express},
Volume = {25},
Number = {20},
Pages = {24199-24214},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1364/oe.25.024199},
Abstract = {In this work, we propose a numerical solver combining the
spectral element - boundary integral (SEBI) method with the
periodic layered medium dyadic Green's function. The
periodic layered medium dyadic Green's function is
formulated under matrix representation. The surface integral
equations (SIEs) are then implemented as the radiation
boundary condition to truncate the top and bottom
computation domain. After describing the interior
computation domain with the vector wave equations, and
treating the lateral boundaries with Bloch periodic boundary
conditions, the whole computation domains are discretized
with mixed-order Gauss- Lobatto-Legendre basis functions in
the SEBI method. This method avoids the discretization of
the top and bottom layered media, so it can be much more
efficient than conventional methods. Numerical results
validate the proposed solver with fast convergence
throughout the whole computation domain and good performance
for typical multiscale nano-optical applications.},
Doi = {10.1364/oe.25.024199},
Key = {fds341180}
}
@article{fds341177,
Author = {Jiang, W and Liu, J and Xia, T and Liu, N and Liu, QH},
Title = {A Necessary and Sufficient Condition for Having Independent
TE and TM Modes in an Anisotropic Waveguide},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {10},
Pages = {3660-3670},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1109/TMTT.2017.2691775},
Abstract = {In a metallic waveguide filled with a lossless anisotropic
medium, do independent transverse electric (TE) and
transverse magnetic (TM) modes exist? If so, under what
conditions? This is a fundamental problem in the
electromagnetic waveguide theory, but so far no definitive
answers have been published in existing references. This
paper proposes a sufficient and necessary condition for this
theoretic electromagnetic waveguide problem based on both
classic waveguide theory in electromagnetics and basic
knowledge in mathematics. Moreover, we prove that for the
independent TE modes, the propagation constants obtained
from both the longitudinal scalar magnetic field simulation
and the transverse vector electric field simulation are the
same, and for the independent TM modes, the propagation
constants obtained from both the longitudinal scalar
electric field simulation and the transverse vector magnetic
field simulation are the same. Finally, we validate the
correctness of this sufficient and necessary condition by
several numerical experiments based on the finite-element
method. Therefore, this is a new theoretical result in the
electromagnetic waveguide theory, and is expected to be
valuable for the design of waveguides filled with
anisotropic media.},
Doi = {10.1109/TMTT.2017.2691775},
Key = {fds341177}
}
@article{fds341178,
Author = {Sun, Q and Ren, Q and Zhan, Q and Liu, QH},
Title = {3-D Domain Decomposition Based Hybrid Finite-Difference
Time-Domain/Finite-Element Time-Domain Method With
Nonconformal Meshes},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {10},
Pages = {3682-3688},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1109/TMTT.2017.2686386},
Abstract = {A new 3-D domain decomposition based hybrid
finite-difference time-domain (FDTD)/finite-element
time-domain (FETD) method is introduced to facilitate
electromagnetic modeling by exploiting both the
computational efficiency of FDTD and the meshing flexibility
of FETD. The proposed hybrid method allows the FETD mesh and
the FDTD grid to be nonconformal based on domain
decomposition technique. It implements the hybridization
with a buffer zone, which functions as a transition region
between FDTD and FETD. The buffer zone helps the proposed
hybrid method obviate the interpolation approach for field
coupling of the nonconformal mesh and hence overcome the
late-time instability issue. The discontinuous Galerkin
method is utilized to couple different regions, thus
improving the coupling accuracy compared with that using the
Dirichlet boundary condition. Moreover, the hybrid method
allows further division of the FETD region into multiple
subdomains when the degrees of freedom in this region are
large. For temporal discretization, a global leapfrog time
integration scheme is implemented to sequentially update the
fields in the FDTD, buffer, and FETD regions. The numerical
results are shown to demonstrate the meshing flexibility and
computational efficiency of the proposed hybrid method
inherited from FETD and FDTD methods.},
Doi = {10.1109/TMTT.2017.2686386},
Key = {fds341178}
}
@article{fds333173,
Author = {Liu, H and Long, Z and Tian, B and Han, F and Fang, G and Liu,
QH},
Title = {Two-Dimensional Reverse-Time Migration Applied to GPR with a
3-D-to-2-D Data Conversion},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {10},
Number = {10},
Pages = {4313-4320},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1109/JSTARS.2017.2734098},
Abstract = {Reverse-time migration (RTM) has shown its advantages over
other conventional migration algorithms for
ground-penetrating radar (GPR) imaging. RTM is preferred to
be implemented in the computationally attractive 2-D domain,
whereas a real measurement can only be conducted in a 3-D
domain. Thus, we propose an asymptotic 3-D-to-2-D data
conversion filter in the frequency domain for preprocessing
of the recorded data for 2-D RTM. The accuracy of the data
conversion filter is verified by two numerical tests on a
homogeneous and a layered model. Then, we evaluate the
effectiveness of the data conversion filter on the imaging
result of 2-D RTM, which is applied to simulated multioffset
GPR data from a buried pipe model. With the filter,
subsurface image by the 2-D RTM matches better with the 3-D
RTM result especially in the aspect of phase congruency.
Therefore, we conclude that this data conversion filter is
necessary for 2-D RTM. We also conducted a laboratory
experiment on a volcanic ash pit using a
multiinput-multioutput GPR system, which is adopted on the
Chang-E 5 lunar exploration lander and works in a stationary
mode. The 3-D-to-2-D data conversion filter is applied to
the measured multioffset GPR data before the 2-D RTM. The
imaging results demonstrate that three marble slabs buried
at different depths up to 2 m are clearly
imaged.},
Doi = {10.1109/JSTARS.2017.2734098},
Key = {fds333173}
}
@article{fds341070,
Author = {Chen, J and Li, J and Liu, QH},
Title = {Analyzing Graphene-Based Absorber by Using the WCS-FDTD
Method},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {10},
Pages = {3689-3696},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1109/TMTT.2017.2690659},
Abstract = {A weakly conditionally stable finite-difference time-domain
(WCS-FDTD) method is used to simulate a graphene-based
absorber. By using the auxiliary differential equation and
Padé fitting method, both the interband and intraband
conductivities of the graphene are incorporated into the
WCS-FDTD method. The time step increment in the proposed
method is not determined by the fine meshes in the graphene
layer, so the computational efficiency of this method is
greatly improved from that of the conventional FDTD method.
By using the proposed WCS-FDTD method, a graphene-based
absorber is simulated and analyzed. The numerical result
shows that the graphene can achieve tunable absorption
through controlling its chemical potential, and the
interband conductivity of the graphene has important effects
on the performance of the absorber.},
Doi = {10.1109/TMTT.2017.2690659},
Key = {fds341070}
}
@article{fds340811,
Author = {Zhan, Q and Zhuang, M and Sun, Q and Ren, Q and Ren, Y and Mao, Y and Liu,
QH},
Title = {Efficient Ordinary Differential Equation-Based Discontinuous
Galerkin Method for Viscoelastic Wave Modeling},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {10},
Pages = {5577-5584},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {October},
url = {http://dx.doi.org/10.1109/TGRS.2017.2710078},
Abstract = {We present an efficient nonconformal-mesh discontinuous
Galerkin (DG) method for elastic wave propagation in viscous
media. To include the attenuation and dispersion due to the
quality factor in time domain, several sets of auxiliary
ordinary differential equations (AODEs) are added. Unlike
the conventional auxiliary partial differential
equation-based algorithm, this new method is highly parallel
with its lossless counterpart, thus requiring much less time
and storage consumption. Another superior property of the
AODE-based DG method is that a novel exact Riemann solver
can be derived, which allows heterogeneous viscoelastic
coupling, in addition to accurate coupling with purely
elastic media and fluid. Furthermore, thanks to the
nonconformal-mesh technique, adaptive hp-refinement and
flexible memory allocation for the auxiliary variables are
achieved. Numerical results demonstrate the efficiency and
accuracy of our method.},
Doi = {10.1109/TGRS.2017.2710078},
Key = {fds340811}
}
@article{fds341181,
Author = {Zhang, Y and Sun, H and Xu, X and Liu, QH},
Title = {Amplitude Angle Monopulse Estimation for the Four-Channel
Hybrid Polarimetric Radar System},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {2889-2893},
Year = {2017},
Month = {September},
url = {http://dx.doi.org/10.1109/LAWP.2017.2751298},
Abstract = {In this letter, the regular amplitude angle monopulse
estimation method is proven not suitable for polarimetric
radars because it sets up correlation between azimuth angle
and elevation angle of the target and can result in low
accuracy. To solve this problem, the polarimetric amplitude
angle monopulse estimation method is proposed to obtain the
correct angle. By changing the channel synthesis method when
the radar receives the signals, the proposed method shows a
higher accuracy than the regular method through formulation
and the experiment results.},
Doi = {10.1109/LAWP.2017.2751298},
Key = {fds341181}
}
@article{fds341182,
Author = {Li, W and Zeng, Z and You, B and Ye, L and Liu, Y and Liu,
QH},
Title = {Compact Dual-Polarized Printed Slot Antenna},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {2816-2819},
Year = {2017},
Month = {September},
url = {http://dx.doi.org/10.1109/LAWP.2017.2748542},
Abstract = {A dual-polarized printed slot antenna is constructed by
inserting the open-end slot into the coplanar waveguide
center conductor of T-shaped slot. In order to verify the
antenna performance, an antenna prototype was fabricated.
The experimental results show that its working bandwidth is
about 10.5%. In the operating frequency band, the isolation
between two ports is higher than 27 dB. The proposed
two-port antenna has bidirectional radiation
characteristics, but the gain of the T-shaped slot element
is higher than that of the open-end slot element. In the
maximum radiation direction, the copolarization level of the
T-shaped slot is 39 dB higher than the cross polarization
and 30 dB for the open-end slot. The proposed dual-polarized
antenna has a compact structure.},
Doi = {10.1109/LAWP.2017.2748542},
Key = {fds341182}
}
@article{fds341183,
Author = {Li, W and Xu, KD and Tang, X and Yang, Y and Liu, Y and Liu,
QH},
Title = {Substrate Integrated Waveguide Cavity-Backed Slot Array
Antenna Using High-Order Radiation Modes for Dual-Band
Applications in $k$-Band},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {9},
Pages = {4556-4565},
Year = {2017},
Month = {September},
url = {http://dx.doi.org/10.1109/TAP.2017.2723089},
Abstract = {A novel compact dual-band cavity-backed substrate integrated
waveguide (SIW) array antenna using high-order radiation
modes has been proposed in this paper. The first high-order
hybrid mode (superposition of TM310 and TM130) and the
second high-order mode (TM320) of K-band in the SIW cavity
are excited by an inductive window for dual-band
application. The operation mechanism of high-order modes is
analyzed and then verified through simulations by inserting
metallic vias in different positions of the resonant SIW
cavity. The designed subarray antenna has the advantages of
high gain, high front-to-back ratio, and low
cross-polarization level. To further validate the design
idea, a dual-frequency band $2 \times 2$ array antenna has
been fabricated and measured including reflection
coefficients, realized gains, and radiation patterns. The
measured results show that the 10-dB impedance bandwidths at
resonant frequencies of 21 and 26 GHz are 800 MHz (3.7%) and
700 MHz (2.6%), and the realized gains at boresight
direction are around 16 and 17.4 dBi, respectively.
Moreover, the proposed array antenna also possesses both
advantages of metallic cavity-backed antennas and planar
patch antennas, such as low cost, easy fabrication with the
printed circuit board technology, and integration with other
planar circuits.},
Doi = {10.1109/TAP.2017.2723089},
Key = {fds341183}
}
@article{fds330589,
Author = {Liu, Y and Zhao, Z and Zhu, X and Yang, W and Nie, Z and Liu,
QH},
Title = {A diagonal subspace-based optimization method for
reconstruction of 2-d isotropic and uniaxial anisotropic
dielectric objects},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {14},
Number = {8},
Pages = {1318-1322},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/LGRS.2017.2710999},
Abstract = {In this letter, a diagonal approximation has been introduced
in the framework of subspace-based optimization method
(SOM), for reducing computational complexity. Due to this
approximation, the operator which relates the electric field
and equivalent current becomes a diagonal one, instead of
the nonlinear one in full-wave inversion. Consequently, the
proposed method is named as diagonal SOM (DSOM). Compared
with the original SOM, DSOM has a more simplified objective
function with much less computational cost. DSOM can be
applied for solving inverse scattering problems involving
not only isotropic objects, but also uniaxial anisotropic
objects, which is demonstrated by numerical examples.
Furthermore, DSOM provides reconstruction results that are
comparable in quality to the ones obtained using SOM, but
with much less computation load.},
Doi = {10.1109/LGRS.2017.2710999},
Key = {fds330589}
}
@article{fds341187,
Author = {Li, JH and Zhang, YJ and Qi, R and Liu, QH},
Title = {Wavelet-Based Higher Order Correlative Stacking for Seismic
Data Denoising in the Curvelet Domain},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {10},
Number = {8},
Pages = {3810-3820},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/JSTARS.2017.2685628},
Abstract = {To whiten random noise and identify coherent noise while
preserving the features of seismic events, a hybrid
denoising scheme of wavelet-based higher order correlative
stacking (HOCS) in the curvelet domain is proposed. The
proposed algorithm uses HOCS to isolate the coefficients of
seismic events in the curvelet domain. It then removes the
noises and recovers signals recorded in noisy environment,
without the need to choose an arbitrary threshold; the HOCS
method selects a threshold automatically in the curvelet
domain. Therefore, with the HOCS, it is possible to capture
the features of useful signals with good correlations at all
scales and all angles, then to remove the features of
coherent noise with disordered correlations. Using
interpretive seismic records of karst cavities and hidden
sinkhole detections after artificial backfill, we show that
the proposed scheme improves noisy seismic data
significantly with respect to both signal-to-noise ratio and
fidelity. To demonstrate the advantages of this hybrid
denoising scheme, a comparison of the performances between
different individual denoising methods is investigated for
complex seismic records contaminated with different types of
noise. Numerical case studies and three field data examples
validate the effectiveness of the hybrid denoising scheme
proposed in this paper.},
Doi = {10.1109/JSTARS.2017.2685628},
Key = {fds341187}
}
@article{fds331498,
Author = {Chen, J and Hao, G and Liu, QH},
Title = {Using the ADI-FDTD Method to Simulate Graphene-Based FSS at
Terahertz Frequency},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {59},
Number = {4},
Pages = {1218-1223},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/TEMC.2017.2650226},
Abstract = {The alternating-direction-implicit finite-difference
time-domain (ADI-FDTD) method is modified to simulate a
graphene-based frequency selective surface. By using the
auxiliary differential equation and Pade fitting method,
both the interband and intraband conductivity of the
graphene are incorporated into the ADI-FDTD method. The
ADI-FDTD method has excellent computational accuracy and its
computational efficiency is considerably improved from that
of the conventional FDTD method. By using the proposed
ADI-FDTD method, a graphene-based frequency selective
surface is simulated and analyzed at terahertz frequency.
The numerical results show that the graphene can achieve a
tunable frequency selective surface through controlling its
chemical potential, and the interband conductivity of the
graphene has important effect on the performance of the
frequency selective surface.},
Doi = {10.1109/TEMC.2017.2650226},
Key = {fds331498}
}
@article{fds341188,
Author = {Zhan, Q and Sun, Q and Ren, Q and Fang, Y and Wang, H and Liu,
QH},
Title = {A discontinuous Galerkin method for simulating the effects
of arbitrary discrete fractures on elastic wave
propagation},
Journal = {Geophysical Journal International},
Volume = {210},
Number = {2},
Pages = {1219-1230},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1093/gji/ggx233},
Abstract = {We develop a non-conformal mesh discontinuous Galerkin (DG)
pseudospectral time domain (PSTD) method for 3-D elastic
wave scattering problems with arbitrary fracture inclusions.
In contrast to directly meshing the exact thin-layer
fracture, we use the linear-slip model, one kind of
transmission boundary condition, for theDGscheme.
Intrinsically,we can efficiently impose a jump-boundary
condition by defining a new numerical flux for the surface
integration in the DG framework. This transmission boundary
condition in the DG-PSTD method significantly reduces the
computational cost. 3-D DG simulations and accurate waveform
comparisons validate our results for arbitrary discrete
fractures. Numerical results indicate that fractures have a
significant influence on wave propagation.},
Doi = {10.1093/gji/ggx233},
Key = {fds341188}
}
@article{fds341184,
Author = {Liu, J and Jiang, W and Lin, F and Liu, N and Liu, QH},
Title = {A Two-Grid Vector Discretization Scheme for the Resonant
Cavity Problem with Anisotropic Media},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {8},
Pages = {2719-2725},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/TMTT.2017.2672545},
Abstract = {Application of the classical finite-element method (FEM) to
the resonant cavity problem leads to nonphysical modes and
expensive computational costs. In this paper, a new two-grid
vector discretization scheme is presented for computing the
resonant cavity problem with lossless anisotropic media in
2-D and 3-D. This scheme is based on the mixed FEM with the
edge element, the shifted-inverse power method, and the
Rayleigh quotient so that it cannot only successfully
suppress all nonphysical modes but also significantly reduce
the computational costs. In addition, this scheme is highly
efficient for the microwave cavity filter and the open
cavity problem. Several numerical results are provided to
show that the scheme is reliable and efficient.},
Doi = {10.1109/TMTT.2017.2672545},
Key = {fds341184}
}
@article{fds341185,
Author = {Liu, Y and Huang, X and Xu, KD and Song, Z and Yang, S and Liu,
QH},
Title = {Pattern Synthesis of Unequally Spaced Linear Arrays
Including Mutual Coupling Using Iterative FFT via Virtual
Active Element Pattern Expansion},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {8},
Pages = {3950-3958},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/TAP.2017.2708081},
Abstract = {A virtual active element pattern (AEP) expansion method is
presented in which each AEP in an unequally spaced array is
considered to be the pattern radiated by a subarray of some
equally spaced virtual elements. With the help of this
method, the pattern of an unequally spaced array including
mutual coupling can be efficiently evaluated by fast Fourier
transform (FFT). By incorporating this idea into the
iterative Fourier transform procedure, we develop a novel
iterative synthesis method, which can apply the iterative
FFT to efficiently synthesize unequally spaced arrays
including mutual coupling. Different excitation constraints,
such as phase-only control and amplitude-phase optimization
with a prescribed dynamic range ratio, can be easily added
into the proposed synthesis procedure. A set of synthesis
examples for different antenna arrays with pencil and shaped
beam patterns are provided to validate the effectiveness and
advantages of the proposed method.},
Doi = {10.1109/TAP.2017.2708081},
Key = {fds341185}
}
@article{fds341186,
Author = {Li, YK and Hu, J and Huang, WF and Nie, ZP and Liu, QH},
Title = {A Spectral Integral Method for Smooth Multilayered Bodies of
Revolution},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {8},
Pages = {4146-4154},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/TAP.2017.2710204},
Abstract = {A spectral integral method (SIM) is developed to solve the
scattering problem from smooth multilayered bodies of
revolution (BoRs). This SIM is a spectral method to improve
the accuracy and efficiency of the SIM by the fast Fourier
transform (FFT) algorithm. This method can achieve high
accuracy and greatly reduce the computational time
consumption. In our BoR-SIM, the BoR generatrix current is
expanded by the truncated Fourier series. Then, the
impedance matrix is generated in the spectral domain to
solve the scattering problem. Unlike the conventional
methods that need eight to ten segments per wavelength, in
the BoR-SIM, two points per wavelength are adequate to
achieve high accuracy according to the Nyquist theorem.
Being accelerated by FFT, this method shows a significant
efficiency advantage over the conventional BoR method.
Numerical results demonstrate the accuracy and efficiency of
our new method. By combining with the Poggio-Miller-Chang-Harrington-Wu-Tsai
surface integral equations, this method can be used to solve
many practical scattering problems.},
Doi = {10.1109/TAP.2017.2710204},
Key = {fds341186}
}
@article{fds341101,
Author = {Liu, Y and Zhao, Z and Zhu, X and Yang, W and Nie, Z and Liu,
QH},
Title = {A diagonalized improved subspace-based optimization method
for solving 2-D inverse scattering problems},
Journal = {Microwave and Optical Technology Letters},
Volume = {59},
Number = {8},
Pages = {2089-2095},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1002/mop.30679},
Abstract = {This letter proposes a diagonalized improved subspace-based
optimization method (DISOM) by introducing the diagonal
approximation to the improved subspace-based optimization
method (ISOM). In the diagonal approximation which has been
used in the contrast source inversion, a diagonal operator
is used to replace the nonlinear operator of full contrast
inversion and relates the fields and induced currents. Due
to the diagonal approximation, a more simplified objective
function is obtained. Consequently, the iteration procedure
is simplified and the computation time is reduced. Numerical
examples demonstrate that the proposed DISOM has the
capability of reconstructing not only isotropic objects but
also uniaxial anisotropic objects. Furthermore, the quality
of the reconstruction results obtained by DISOM is almost
the same as the ones by utilizing ISOM, while DISOM saves
about one fourth of the computational time.},
Doi = {10.1002/mop.30679},
Key = {fds341101}
}
@article{fds340877,
Author = {Cai, QM and Zhang, ZP and Zhao, YW and Huang, WF and Zheng, YT and Nie, ZP and Liu, QH},
Title = {Nonconformal Discretization of Electric Current Volume
Integral Equation with Higher Order Hierarchical Vector
Basis Functions},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {8},
Pages = {4155-4169},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1109/TAP.2017.2710211},
Abstract = {A nonconformal discretization of the electric current volume
integral equation (JVIE) is presented for the
electromagnetic scattering analysis of inhomogeneous
dielectric objects. This JVIE is based on higher order
geometrical and current modeling, where curved tetrahedral
elements and higher order hierarchical vector (HOHV) basis
functions are adopted. In order to implement the
nonconformal discretization, the half face-based HOHV basis
function is introduced to address the nonconformal
volumetric elements. Compared to the conventional low-order
conformal/nonconformal VIE, our nonconformal HOHV-based JVIE
has the advantage of improving the computational efficiency
and accuracy. Compared to the previous VIE discretized by
other higher order functions, our nonconformal JVIE is based
on the higher order geometric modeling and the HOHV bases.
In order to improve the efficiency, the basis expansion and
recombination technique is introduced to significantly
accelerate the matrix filling. Moreover, the flexibility of
basis order selection is further enhanced by the mixed order
schemes. Numerical results are given to demonstrate its
accuracy, efficiency, and flexibility.},
Doi = {10.1109/TAP.2017.2710211},
Key = {fds340877}
}
@article{fds340734,
Author = {Yao, J and Chen, Y and Ye, L and Liu, N and Cai, G and Liu,
QH},
Title = {Multiple resonant excitations of surface plasmons in a
graphene stratified slab by Otto configuration and their
independent tuning},
Journal = {Photonics Research},
Volume = {5},
Number = {4},
Pages = {377-384},
Publisher = {The Optical Society},
Year = {2017},
Month = {August},
url = {http://dx.doi.org/10.1364/PRJ.5.000377},
Abstract = {Multiple resonant excitations of surface plasmons in a
graphene stratified slab are realized by Otto configuration
at terahertz frequencies. The proposed graphene stratified
slab consists of alternating dielectric layers and graphene
sheets, and is sandwiched between a prism and another
semi-infinite medium. Optical response and field
distribution are determined by the transfer matrix method
with the surface current density boundary condition.
Multiple resonant excitations appear on the angular
reflection spectrum, and are analyzed theoretically via the
phase-matching condition. Furthermore, the effects of the
system parameters are investigated. Among them, the Fermi
levels can tune the corresponding resonances independently.
The proposed concept can be engineered for promising
applications, including angular selective or multiplex
filters, multiple channel sensors, and directional delivery
of energy.},
Doi = {10.1364/PRJ.5.000377},
Key = {fds340734}
}
@article{fds341071,
Author = {Liu, S and Zhao, Z and Zhu, X and Lu, Y and Wang, B and Nie, Z and Liu,
QH},
Title = {Block based compressive sensing method of microwave induced
thermoacoustic tomography for breast tumor
detection},
Journal = {Journal of Applied Physics},
Volume = {122},
Number = {2},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1063/1.4994168},
Abstract = {Microwave induced thermoacoustic tomography (MITAT) is a
developing non-ionized technique which has great potential
in early breast tumor detection. In our previous work, an
imaging method, CS-MITAT, was proposed, which applied the
compressive sensing theory in MITAT and achieved a good
image. The method converts a signal model into an
unconstrained optimization problem with 1 norm
regularization, which only exploits the spatial sparsity of
targets. In this paper, based on the block sparsity of
thermoacoustic signals and target distribution in MITAT, the
signals to be detected can be grouped into several blocks
and the summation of 2 norm regularization is used to
replace the 1 norm regularization of the CS-MITAT method.
The combination of 2 and 1 norm regularizations helps the
aggregation of nonzero elements which are accumulated in
blocks. A priori structural constraint is added to form a
more realistic signal model which can improve the image
quality. Compared with the conventional approach of time
reversal mirror and the method of gradient projection for
sparse reconstruction, the alternating direction method of
multipliers is applied to solve the convex optimization
problem. Simulations and experiments on a real breast tumor
demonstrate the effectiveness of the proposed
method.},
Doi = {10.1063/1.4994168},
Key = {fds341071}
}
@article{fds330590,
Author = {Chen, Y and Wen, P and Han, F and Liu, N and Liu, H and Liu,
QH},
Title = {Three-Dimensional Reconstruction of Objects Embedded in
Spherically Layered Media Using Variational Born Iterative
Method},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {14},
Number = {7},
Pages = {1037-1041},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1109/LGRS.2017.2694007},
Abstract = {The variational Born iterative method (VBIM) is employed
here to reconstruct 3-D objects with permittivity contrast
buried in spherically multilayered media. The nonlinear
inverse problem is solved iteratively via the
conjugate-gradient method, and in each iteration, the
scattered field is linearized by using the Born
approaximation. The forward solver is provided by the method
of moments combined with a Krylov subspace method. The
dyadic Green's function for spherically layered media is
constructed in terms of the spherical vector wave functions
by using the scattering superposition in the spherical
coordinate system and then transformed into the Cartesian
coordinate system. Thus, the inversion region is discretized
into N uniform cubic cells and the reconstructed result can
be obtained in the Cartesian coordinate system by employing
VBIM. Numerical results with high resolution are presented
to validate the capability of our method in reconstructing
3-D multiple objects of arbitrary shapes buried in
spherically multilayered media.},
Doi = {10.1109/LGRS.2017.2694007},
Key = {fds330590}
}
@article{fds341102,
Author = {Wang, Z and Zhang, B and Gao, J and Wang, Q and Liu,
QH},
Title = {Wavelet transform with generalized beta wavelets for seismic
time-frequency analysis},
Journal = {Geophysics},
Volume = {82},
Number = {4},
Pages = {O47-O56},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1190/GEO2016-0342.1},
Abstract = {Using the continuous wavelet transform (CWT), the
timefrequency analysis of reflection seismic data can
provide significant information to delineate subsurface
reservoirs. However, CWT is limited by the Heisenberg
uncertainty principle, with a trade-off between time and
frequency localizations. Meanwhile, the mother wavelet
should be adapted to the real seismic waveform. Therefore,
for a reflection seismic signal, we have developed a
progressive wavelet family that is referred to as
generalized beta wavelets (GBWs). By varying two parameters
controlling the wavelet shapes, the time-frequency
representation of GBWs can be given sufficient flexibility
while remaining exactly analytic. To achieve an adaptive
trade-off between time-frequency localizations, an
optimization workflow is designed to estimate suitable
parameters of GBWs in the timefrequency analysis of seismic
data. For noise-free and noisy synthetic signals from a
depositional cycle model, the results of spectral component
using CWT with GBWs display its flexibility and robustness
in the adaptive time-frequency representation. Finally, we
have applied CWT with GBWs on 3D seismic data to show its
potential to discriminate stacked fluvial channels in the
vertical sections and to delineate more distinct fluvial
channels in the horizontal slices. CWTwith GBWs provides a
potential technique to improve the resolution of exploration
seismic interpretation.},
Doi = {10.1190/GEO2016-0342.1},
Key = {fds341102}
}
@article{fds341189,
Author = {Jiang, W and Liu, J and Xiong, X and Liu, QH},
Title = {Finite Element Method for Resonant Cavity Problem with
Complex Geometrical Structure and Anisotropic Fully
Conducting Media},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {7},
Pages = {2240-2248},
Year = {2017},
Month = {July},
url = {http://dx.doi.org/10.1109/TMTT.2017.2661740},
Abstract = {In this paper, the resonant cavity problem with anisotropic
fully conducting media, complex geometrical structure and
perfect electric conductor walls is investigated. We solve
this problem based on the finite element method (FEM) with
tangential and linear normal (CT/LN) element and standard
linear element. An effective numerical method is proposed by
us such that it is free of nonphysical modes. After the FEM
discretization, we need to solve a quadratic algebraic
eigenvalue problem with a linear constraint condition. In
order to overcome this difficulty in the field of numerical
algebra, we change this algebraic eigenvalue problem into a
generalized eigenvalue problem by introducing an auxiliary
zero eigenvector. Moreover, when the permittivity and
conductivity are two constants, both the eigenmodes of
infinite algebraic multiplicity and all the nonphysical
modes are also removed by linearization method. Several
numerical experiments show that computational method in this
paper can suppress all the spurious modes.},
Doi = {10.1109/TMTT.2017.2661740},
Key = {fds341189}
}
@article{fds341103,
Author = {Zhu, C and Li, X and Liu, Y and Liu, L and Liu, QH},
Title = {An Extended Generalized Matrix Pencil Method to Synthesize
Multiple-Pattern Frequency-Invariant Linear
Arrays},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {2311-2315},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1109/LAWP.2017.2715860},
Abstract = {This letter develops an extended generalized matrix pencil
method (EGMPM) for the synthesis of multiple-pattern
frequency-invariant linear arrays. In this method, all the
pattern data sampled from different frequencies and
different patterns are organized into a Hankel matrix. The
problem of estimating the best common excitations and
locations is converted into solving a singular value
decomposition and some least-square problems. The previously
proposed generalized matrix pencil method and extended
matrix pencil method are both special cases of the EGMPM. A
set of numerical experiments on Chebyshev pattern, shaped
pattern, Taylor pattern, pencil-beam pattern, and flat-beam
pattern is shown to validate the proposed
method.},
Doi = {10.1109/LAWP.2017.2715860},
Key = {fds341103}
}
@article{fds341104,
Author = {Wang, C and Li, J and Zhang, A and Joines, WT and Liu,
QH},
Title = {Dual-band capacitively loaded annular-ring slot antenna for
dual-sense circular polarization},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {31},
Number = {9},
Pages = {867-878},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1080/09205071.2017.1326322},
Abstract = {This paper investigates a simplified and new capacitively
loaded annular-ring slot antenna (ARSA) for dual-band and
dual-sense circular polarization. The antenna is comprised
of two concentric annular-ring slots coupled to a microstrip
feed line to achieve dual-band operation. With introducing
proper distributed capacitances fulfilled by two closely
spaced T-shaped arc strips across the outer and inner
annular-ring slots at opposite positions with respect to the
microstrip feed line, the dual-sense circular polarization
can hence be obtained. The antenna features that the
impedance and circular polarization characteristic for the
upper band can be independently adjusted. Numerical analysis
and experimental validation have been carried out. The
measured 10-dB return loss impedance bandwidths for both
bands are greater than 22.0%. The measured 3-dB axial ratio
(AR) bandwidths are 3.6 and 5.6%, respectively, for the
lower and upper bands.},
Doi = {10.1080/09205071.2017.1326322},
Key = {fds341104}
}
@article{fds341191,
Author = {Yang, H and Li, N and Li, T and Liu, J and Liu, QH},
Title = {An improved Stolt migration algorithm based on high sampling
freedom degree for borehole array radar imaging},
Journal = {2017 Ieee Radar Conference, Radarconf 2017},
Pages = {0739-0744},
Year = {2017},
Month = {June},
ISBN = {9781467388238},
url = {http://dx.doi.org/10.1109/RADAR.2017.7944301},
Abstract = {An improved Stolt migration algorithm is proposed for the
borehole array radar imaging by employing the high sampling
freedom degree of virtual sample set. To handle the borehole
array radar samples efficiently, the original samples are
firstly expanded to a virtual sample set with higher
sampling freedom degree and then processed by modified Stolt
migration algorithm. The relation between sample space and
target space is derived and simplified for the formation of
modified Stolt migration algorithm in the frame of borehole
array radar. The improved approach is compared with the
conventional Stolt migration algorithm, back projection
method, and Kirchhoff migration algorithm with synthetic
data. The results demonstrate the developed approach is
superior to the conventional methods in borehole array radar
imaging.},
Doi = {10.1109/RADAR.2017.7944301},
Key = {fds341191}
}
@article{fds341190,
Author = {Li, N and Yang, H and Cui, G and Kong, L and Liu, QH},
Title = {Two-step Bayesian detection for MIMO radar in
compound-Gaussian clutter with Gamma texture},
Journal = {2017 Ieee Radar Conference, Radarconf 2017},
Pages = {0146-0151},
Year = {2017},
Month = {June},
ISBN = {9781467388238},
url = {http://dx.doi.org/10.1109/RADAR.2017.7944187},
Abstract = {In this paper, we consider the adaptive detection with
multiple-input multiple-output (MIMO) radar in
compound-Gaussian clutter. The covariance matrices of the
primary and the secondary data share a common structure but
different power levels (textures). A Bayesian framework is
exploited where both the textures and the structure are
assumed to be random. Precisely, the textures follow Gamma
distribution and the structure is drawn from an inverse
complex Wishart distribution. In this framework, an adaptive
generalized likelihood ratio test (GLRT) is developed using
two-step design procedure. Precisely, we first obtain the
GLRT by assuming the known clutter structure. Then, we
derive the maximum a posteriori (MAP) estimator of the
structure, and substitute it into the obtained GLRT.
Finally, we evaluate the capabilities of the proposed
detector against compound-Gaussian clutter as well as their
superiority with respect to some existing
techniques.},
Doi = {10.1109/RADAR.2017.7944187},
Key = {fds341190}
}
@article{fds331500,
Author = {Zhou, Y and Shi, L and Liu, N and Zhu, C and Sun, Y and Liu,
QH},
Title = {Mixed Spectral-Element Method for Overcoming the
Low-Frequency Breakdown Problem in Subsurface em
Exploration},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {6},
Pages = {3488-3500},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1109/TGRS.2017.2674685},
Abstract = {One fundamental difficulty in low-frequency subsurface
electromagnetic exploration is the low-frequency breakdown
phenomenon in numerical computation. It makes the
discretized linear system very poorly conditioned and thus
difficult to solve. This issue is present in both integral
equation and partial differential equation solution methods,
and thus has attracted many researchers who have proposed
various methods to overcome this difficulty. In this paper,
we propose a new mixed spectral element method (mixed SEM)
to eliminate this low-frequency breakdown problem and apply
this method to solve the subsurface electromagnetic
exploration problem. Since Gauss' law is now explicitly
enforced in the mixed SEM to make the system matrix
well-conditioned even at extremely low frequency, we can
solve the linear system from dc to high frequencies. With
the proposed method, we study the surface-to-borehole
electromagnetic system for hydrocarbon exploration.
Numerical examples show that the mixed SEM is accurate and
efficient, and has significant advantages over conventional
methods.},
Doi = {10.1109/TGRS.2017.2674685},
Key = {fds331500}
}
@article{fds341105,
Author = {You, P and Liu, Y and Xu, K and Zhu, C and Liu, QH},
Title = {Generalisation of genetic algorithm and fast Fourier
transform for synthesising unequally spaced linear array
shaped pattern including coupling effects},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {11},
Number = {6},
Pages = {827-832},
Year = {2017},
Month = {May},
url = {http://dx.doi.org/10.1049/iet-map.2016.0773},
Abstract = {Antenna arrays with shaped patterns have drawn significant
attention for their wide applications in radar, sonar and
communication systems. The combination of genetic algorithm
(GA) and fast Fourier transform (FFT) has been used to
synthesise shaped pattern of antenna array's factor without
considering coupling effects. In this work, the GA-FFT
method is generalised by integrating with a new virtual
active element pattern (AEP) expansion method which
approximates each AEP as the radiation pattern by exciting
several equally spaced virtual elements surrounding the real
element position. The generalised GA-FFT can be applied for
the shaped pattern synthesis of unequally spaced linear
arrays including mutual coupling and platform effect.
Several synthesis examples with different pattern shapes and
different antenna structures are given to demonstrate the
effectiveness, accuracy and robustness of the proposed
method.},
Doi = {10.1049/iet-map.2016.0773},
Key = {fds341105}
}
@article{fds330591,
Author = {Yang, Y and Zhao, Z and Yang, W and Nie, Z and Liu, QH},
Title = {Compact multimode monopole antenna for metal-rimmed mobile
phones},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {5},
Pages = {2297-2304},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {May},
url = {http://dx.doi.org/10.1109/TAP.2017.2679059},
Abstract = {A compact multimode monopole antenna for hepta-band
metal-rimmed smartphones is proposed. The metal bezel is
kept unbroken and no lumped element is needed. To cover the
low band, the bezel mode is excited by a capacitive coupling
vertical plate, and a bandwidth enhancement technique is
introduced for this mode. For the high band, printed
multiple branches on both sides of substrate are well
designed to obtain multiple modes to cover a wide band. With
the proposed structure, the frequency bands can be widened
by tuning and optimization. The new-type monopole occupies
an area of 60 × 5 × 5 mm3 on a 120 × 60mm2 system board,
which has a narrow ground clearance and a low profile. A
prototype is fabricated and measured to validate the
proposed design. Measured results show that the proposed
antenna has two impedance bands with S11 less than -6 dB,
i.e., 23% for the low band (0.76-0.96 GHz) and 57% for the
high band (1.51-2.72 GHz). The proposed monopole antenna is
capable of covering the GSM/DCS/PCS/UMTS and LTE2300/2500
bands for modern metal-rimmed mobile phone
applications.},
Doi = {10.1109/TAP.2017.2679059},
Key = {fds330591}
}
@article{fds341072,
Author = {Ren, Y and Chen, Y and Zhan, Q and Niu, J and Liu, QH},
Title = {A higher order hybrid SIE/FEM/SEM method for the flexible
electromagnetic simulation in layered medium},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {5},
Pages = {2563-2574},
Year = {2017},
Month = {May},
url = {http://dx.doi.org/10.1109/TGRS.2016.2647618},
Abstract = {A novel hybrid method is developed for the flexible and
accurate electromagnetic simulation of penetrable objects in
a layered medium (LM). In this method, the original complex
simulation domain is first divided into several subdomains,
following the spirit of divide-and-conquer. Each subdomain
is then meshed and solved independently, where nonconformal
mesh is inevitable. The Riemann type transmission condition
is utilized at the interfaces of each subdomain to correctly
exchange information so that the solutions of all subdomains
converge rapidly to the real solution of the original
problem. More specifically, in our method, the surface
integral equation (SIE) combined with the LM Green's
functions (LMGFs) is adopted for the boundary subdomain,
while the finite-element method (FEM) and the spectral
element method (SEM) are employed for all the other interior
dielectric subdomains. The SIE with LMGFs truncates the
simulation domain tightly within the object itself, which
drastically decreases the number of unknowns. The interior
subdomains are modeled by either FEM or SEM, depending on
the geometry and material property of each subdomain. To
further enhance the simulation capability, higher order
approaches are adopted for all the subdomain solvers in this
hybrid method. Several numerical examples are demonstrated,
where a high convergence and accuracy of this method is
observed. This paper will serve as an efficient and flexible
simulation tool for the applications of geophysical
exploration.},
Doi = {10.1109/TGRS.2016.2647618},
Key = {fds341072}
}
@article{fds340721,
Author = {Ye, L and Chen, Y and Cai, G and Liu, N and Zhu, J and Song, Z and Liu,
QH},
Title = {Broadband absorber with periodically sinusoidally-patterned
graphene layer in terahertz range.},
Journal = {Optics Express},
Volume = {25},
Number = {10},
Pages = {11223-11232},
Year = {2017},
Month = {May},
url = {http://dx.doi.org/10.1364/oe.25.011223},
Abstract = {We demonstrate that a broadband terahertz absorber with
near-unity absorption can be realized using a net-shaped
periodically sinusoidally-patterned graphene sheet, placed
on a dielectric spacer supported on a metallic reflecting
plate. Because of the gradient width modulation of the unit
graphene sheet, continuous plasmon resonances can be
excited, and therefore broadband terahertz absorption can be
achieved. The results show that the absorber's normalized
bandwidth of 90% terahertz absorbance is over 65% under
normal incidence for both TE and TM polarizations when the
graphene chemical potential is set as 0.7 eV. And the
broadband absorption is insensitive to the incident angles
and the polarizations. The peak absorbance remains more than
70% over a wide range of the incident angles up to 60° for
both polarizations. Furthermore, this absorber also has the
advantage of flexible tunability via electrostatic doping of
graphene sheet, which peak absorbance can be continuously
tuned from 14% to 100% by controlling the chemical potential
from 0 eV to 0.8 eV. The design scheme is scalable to
develop various graphene-based tunable broadband absorbers
at other terahertz, infrared, and visible frequencies, which
may have promising applications in sensing, detecting, and
optoelectronic devices.},
Doi = {10.1364/oe.25.011223},
Key = {fds340721}
}
@article{fds330592,
Author = {Chen, J and Li, J and Liu, QH},
Title = {Designing Graphene-Based Absorber by Using HIE-FDTD
Method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {4},
Pages = {1896-1902},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1109/TAP.2017.2670610},
Abstract = {A hybrid implicit explicit-finite-difference time-domain
(HIE-FDTD) method is used to simulate a graphene-based
absorber. Both the interband conductivity and intraband
conductivity of the graphene are incorporated into the
HIE-FDTD method directly through an auxiliary difference
equation. Because the time step size in the proposed method
is not confined by the fine spatial cells in the graphene
layer, the simulation time of the proposed method is greatly
reduced compared with that of the conventional FDTD method.
By using the proposed HIE-FDTD method, a graphene-based
absorber is simulated and analyzed. The numerical result
shows that the operating frequency of the absorber is
tunable through controlling graphene's chemical potential.
It also shows that the interband conductivity has an
important effect on the performance of the graphene device,
especially at the frequency band larger than 10
THz.},
Doi = {10.1109/TAP.2017.2670610},
Key = {fds330592}
}
@article{fds341194,
Author = {Hong, D and Huang, WF and Chen, H and Liu, QH},
Title = {Novel and Stable Formulations for the Response of
Horizontal-Coil Eccentric Antennas in a Cylindrically
Multilayered Medium},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {65},
Number = {4},
Pages = {1967-1977},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1109/TAP.2017.2670360},
Abstract = {In this paper, we present a set of novel and stable
formulations to calculate the response of logging tools with
horizontal-coil antennas in an eccentric borehole straddling
cylindrically multilayered formations. It can be applied in
fast forward computation and the inverse problem for
electromagnetic (EM) well-logging in deviated and horizontal
wells, where eccentric scenarios are often encountered. Our
formulations are different from previous ones in following
aspects. First, the tool mandrel can be cylindrically
multilayered and the electrical parameters of each layer are
arbitrary. Namely, it is not limited to being perfectly
metallic. Second, the EM propagation in inhomogeneous medium
is considered by the generalized reflection and transmission
method, in place of the transfer matrices. The associated
generalized reflection and transmission coefficients are
expressed by the ratios of Bessel or Hankel functions that
obviate the notorious overflow problem for numerical
computation. Finally, a set of linear matrix functions are
constructed to solve for the EM waves in a borehole based on
the concept of the generalized reflection, rather than that
of the fictitious boundary. Numerical results in comparison
with those from other approaches have demonstrated the
validity and stability of our new formulations.},
Doi = {10.1109/TAP.2017.2670360},
Key = {fds341194}
}
@article{fds341192,
Author = {Sun, Q and Zhan, Q and Ren, Q and Liu, QH},
Title = {Wave Equation-Based Implicit Subdomain DGTD Method for
Modeling of Electrically Small Problems},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {4},
Pages = {1111-1119},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1109/TMTT.2016.2640312},
Abstract = {A second-order wave equation-based implicit discontinuous
Galerkin time-domain (DGTD) method is proposed to
efficiently model electrically small problems. The proposed
method employs the second-order wave equation for electric
field (or magnetic field) as the governing equation of the
DG formulation, instead of the first-order Maxwell's curl
equations. A modified version of the Riemann solver (upwind
flux) is introduced to evaluate the numerical flux resulting
from the weak form of the wave equation. Compared with
previous first-order Maxwell's curl equation-based implicit
DGTD methods, which typically solve all electric and
magnetic field unknowns for each subdomain, the proposed
method only needs to solve for the electric field unknowns
plus the surface magnetic field unknowns at subdomain
interfaces. This reduces the dimensions of the resultant
linear system and thus allows for modeling larger problems.
Furthermore, unlike element-based DGTD methods, the proposed
method is subdomain-based. The computational region is
divided into multiple subdomains based on the
domain-decomposition method, and each subdomain may contain
multiple elements. Different element types and orders of
basis functions can be employed in different subdomains to
exploit the geometry property of the model. A nonconformal
mesh is allowed between different subdomains to increase
meshing flexibility. The Newmark-beta time-integration
scheme is used for implicit temporal discretization, and
fast direct linear solvers, such as the lower-diagonal-upper
decomposition algorithm, are employed to accelerate time
integration when all the subdomains are in a sequential
order. Numerical results show that the proposed method is
more efficient in terms of CPU time, and also saves memory
with respect to the previous implicit DGTD method when
modeling electrically small problems.},
Doi = {10.1109/TMTT.2016.2640312},
Key = {fds341192}
}
@article{fds341193,
Author = {Ren, Q and Zhan, Q and Liu, QH},
Title = {An Improved Subdomain Level Nonconformal Discontinuous
Galerkin Time Domain (DGTD) Method for Materials With
Full-Tensor Constitutive Parameters},
Journal = {Ieee Photonics Journal},
Volume = {9},
Number = {2},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1109/JPHOT.2017.2672644},
Abstract = {Ultrawideband simulation of negative refraction in
bicrystals is important for the design optimization of
devices involving such anisotropic media, but it is a
nontrivial task, especially when low-order methods are
utilized. This work proposes an improved discontinuous
Galerkin time domain (DGTD) method for simulating
time-dependent electromagnetic fields for inhomogeneous
media with full anisotropic constitutive parameters (full
anisotropic media). It employs the electric field intensity
E and magnetic flux density B to solve Maxwell's equations.
The EB-scheme-based anisotropic Riemann solver and
nonconformal mesh are employed for domain decomposition to
allow efficient spatial discretization. An unsplit-field
Maxwellian multiaxial perfectly matched layer for full
anisotropic media is derived and shown to be effective to
absorb outgoing waves and suppress the potential late-time
instability found in classical PML. In addition, the
total-field/scattered-field technique is further studied to
allow a nonconformal mesh, vector basis functions, and
half-space situation. This newly improved DGTD method is
validated with test cases and applied to the negative
reflection in YVO4 bicrystal.},
Doi = {10.1109/JPHOT.2017.2672644},
Key = {fds341193}
}
@article{fds331501,
Author = {Wen, P and Chen, Y and Han, F and Liu, N and Liu, H and Liu,
QH},
Title = {Three-Dimensional Scattering and Inverse Scattering from a
Disturbed Region in Planarly Layered Cold Unmagnetized
Plasma Media},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {14},
Number = {4},
Pages = {559-563},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1109/LGRS.2017.2658682},
Abstract = {We apply the forward scattering and inverse scattering
algorithms to a cold unmagnetized plasma region within a
multilayered background medium. Each layer has a different
plasma frequency. The disturbed region in the plasma has an
arbitrary shape, so it is an electromagnetic wave scatterer
and can exist in any layer. The stabilized
biconjugate-gradient fast Fourier transform (BCGS-FFT)
algorithm is used to compute the scattered field. The
scattered fields calculated by the BCGS-FFT yield excellent
agreement with simulated results from the commercial
software. In the inverse scattering process, the variational
Born iterative method is used to reconstruct the relative
permittivity, and thus the plasma frequency of the disturbed
region. Multiple frequencies are adopted to determine the
dispersive property of the plasma medium.},
Doi = {10.1109/LGRS.2017.2658682},
Key = {fds331501}
}
@article{fds341073,
Author = {Yang, S and Hong, D and Huang, WF and Liu, QH},
Title = {A Stable Analytic Model for Tilted-Coil Antennas in a
Concentrically Cylindrical Multilayered Anisotropic
Medium},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {14},
Number = {4},
Pages = {480-483},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1109/LGRS.2017.2647978},
Abstract = {A set of compact and stable formulations is presented to
calculate the response of logging tools employing
tilted-coil antennas in anisotropic concentrically
cylindrical multilayered formation. The presented
formulations can be used to investigate the effect of
mandrel, borehole, and invasion. Our formulations are
different from previous ones in three aspects. First, the
tool mandrel can be cylindrically multilayered, and
electrical parameters of each layer are arbitrary. That is
to say, the mandrel is not limited to being perfectly
metallic. Second, the formation can be either anisotropic or
isotropic. Finally, the propagation of electromagnetic wave
in an inhomogeneous cylindrical medium is described by the
generalized reflection and transmission coefficients without
the numerical overflow issue. Numerical results in
comparison with those from other approaches have
demonstrated the validity and stability of our new
formulations.},
Doi = {10.1109/LGRS.2017.2647978},
Key = {fds341073}
}
@article{fds331502,
Author = {Zhu, J and Zhang, L and Bai, Y and Liu, H and Feng, N and Zhou, J and Zeng, B and Lin, T and Liu, QH},
Title = {Simultaneous Fabrication of Two Kinds of Plasmonic Crystals
by One Nanoimprint Mold},
Journal = {Ieee Photonics Technology Letters},
Volume = {29},
Number = {6},
Pages = {504-506},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2017},
Month = {March},
url = {http://dx.doi.org/10.1109/LPT.2017.2649543},
Abstract = {Plasmonic crystals (e.g., metallic nanohole arrays and
metallic nanoparticle arrays) are widely used in the field
of nanophotonics due to their effects on light confinement.
Soft nanoimprint lithography is a promising technology for
large-scale production of high-quality plasmonic crystals in
industry. However, this technology suffers from a high cost
of the solid mold with a limited pattern for lithography. In
order to reduce the cost, we develop an approach to
simultaneous fabrication of both a plasmonic nanohole array
and a plasmonic nanoparticle array by only using one solid
mold. They show good morphological uniformity, and
demonstrate high efficiencies of light trapping in the
visible range and the infrared range, respectively. In
combination with electromagnetic simulation, we can
preliminarily design the expensive mold and guide the
production of plasmonic crystals more efficiently.},
Doi = {10.1109/LPT.2017.2649543},
Key = {fds331502}
}
@article{fds341106,
Author = {Zheng, J and Liu, H and Liu, Z and Liu, QH},
Title = {ISAR Imaging of Ship Targets Based on an Integrated Cubic
Phase Bilinear Autocorrelation Function.},
Journal = {Sensors (Basel, Switzerland)},
Volume = {17},
Number = {3},
Pages = {E498},
Year = {2017},
Month = {March},
url = {http://dx.doi.org/10.3390/s17030498},
Abstract = {For inverse synthetic aperture radar (ISAR) imaging of a
ship target moving with ocean waves, the image constructed
with the standard range-Doppler (RD) technique is blurred
and the range-instantaneous-Doppler (RID) technique has to
be used to improve the image quality. In this paper, azimuth
echoes in a range cell of the ship target are modeled as
noisy multicomponent cubic phase signals (CPSs) after the
motion compensation and a RID ISAR imaging algorithm is
proposed based on the integrated cubic phase bilinear
autocorrelation function (ICPBAF). The ICPBAF is bilinear
and based on the two-dimensionally coherent energy
accumulation. Compared to five other estimation algorithms,
the ICPBAF can acquire higher cross term suppression and
anti-noise performance with a reasonable computational cost.
Through simulations and analyses with the synthetic model
and real radar data, we verify the effectiveness of the
ICPBAF and corresponding RID ISAR imaging
algorithm.},
Doi = {10.3390/s17030498},
Key = {fds341106}
}
@article{fds341196,
Author = {Zhan, Q and Ren, Q and Sun, Q and Chen, H and Liu, QH},
Title = {Isotropic Riemann Solver for a Nonconformal Discontinuous
Galerkin Pseudospectral Time-Domain Algorithm},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {3},
Pages = {1254-1261},
Year = {2017},
Month = {March},
url = {http://dx.doi.org/10.1109/TGRS.2016.2621124},
Abstract = {We present a discontinuous Galerkin pseudospectral
time-domain (DG-PSTD) algorithm to solve
elastic-/acoustic-wave propagation problems. The developed
DG-PSTD algorithm combines the merits of flexibility from a
finite-element method and spectral accuracy and efficiency
from a high-order pseudospectral method, while having a
flavor closer to a finite-volume method. This numerical
approach not only uses structured/unstructured conformal
meshes but also handles nonconformal meshes (h-adaptivity)
with nonuniform approximation orders (p-adaptivity) in
different regions, thus leading to high flexibility and
efficiency for heterogeneous multiscale problems. To
implement the discontinuous Galerkin algorithm, a concise
but more general heterogeneous Riemann solver is provided to
effectively and accurately resolve the coupling of multiple
subdomains for both elastic-elastic/fluid-fluid and
fluid-solid coupling. Finally, numerical results demonstrate
the flexibility, high accuracy, and efficiency of our method
for elastic-/acoustic-wave simulation.},
Doi = {10.1109/TGRS.2016.2621124},
Key = {fds341196}
}
@article{fds341107,
Author = {Yang, J and Liu, YH and Bai, JJ and Liu, QH and Nie,
ZP},
Title = {Optimal Directivity Synthesis of an Arbitrary Array Subject
to Sidelobe and Cross-Polarization Constraints},
Journal = {Tien Tzu Hsueh Pao/Acta Electronica Sinica},
Volume = {45},
Number = {3},
Pages = {712-718},
Year = {2017},
Month = {March},
url = {http://dx.doi.org/10.3969/j.issn.0372-2112.2017.03.031},
Abstract = {Definitions of the desired co-polarization and
cross-polarization directions are given for a scanned
beampattern according to a desired polarization
direction.Furthermore, the co-polarization directivity is
defined to more accurately represents the degree of the
concentration of co-polarization field over the total
radiated power.With this definition, the co-polarization
directivity can be optimized.Its analytical expression can
be derived when no more pattern constraints exist.In more
general cases in which the constraints on the sidelobe
level, nulling points and cross-polarization level exist, an
efficient numerical algorithm based on convex optimization
is proposed.Some numerical synthesis experiments are
conducted, and the results show the effectiveness and
robustness of the proposed synthesis techniques.},
Doi = {10.3969/j.issn.0372-2112.2017.03.031},
Key = {fds341107}
}
@article{fds341197,
Author = {Xu, KD and Xu, H and Liu, YH and Liu, QH and Zeng, Q},
Title = {A printed quasi-Yagi antenna with dual-stub-loaded parasitic
strip director for bandwidth enhancement},
Journal = {Microwave and Optical Technology Letters},
Volume = {59},
Number = {2},
Pages = {447-451},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1002/mop.30298},
Abstract = {A novel printed quasi-Yagi antenna with dual stubs loaded on
a parasitic strip director has been presented. The impedance
bandwidth is analyzed and compared when we add or eliminate
the parasitic strip director. Then, two open stubs are
loaded on the strip to excite an additional resonant mode,
which lead to a wider impedance bandwidth. To demonstrate
the effectiveness of this design, an antenna prototype is
fabricated and tested. Experimental results show that the
antenna provides a bandwidth ranging from 4.4 to 9.3 GHz and
within the whole band larger than 4.1 dBi gain is achieved.
Additionally, the proposed antenna presents a stable
end-fire radiation directivity and low cross-polarization
level at different frequencies with a compact structural
size of 35 mm × 26 mm. © 2016 Wiley Periodicals, Inc.
Microwave Opt Technol Lett 59:447–451,
2017.},
Doi = {10.1002/mop.30298},
Key = {fds341197}
}
@article{fds341075,
Author = {Fang, Y and Dai, J and Yu, Z and Zhou, J and Liu, QH},
Title = {Through-Casing Hydraulic Fracture Evaluation by Induction
Logging I: An Efficient em Solver for Fracture
Detection},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {55},
Number = {2},
Pages = {1179-1188},
Year = {2017},
Month = {February},
url = {http://dx.doi.org/10.1109/TGRS.2016.2620482},
Abstract = {Hydraulic fracturing is an essential way to improve the
production of unconventional shale oil and gas. It is
important to characterize the produced fractures using
either acoustic or electromagnetic (EM) methods.
Conventional EM solvers in the low-frequency range face
significant challenges by such multiscale problems where the
fracture width is orders of magnitude smaller than its
diameters. Furthermore, the cased borehole environment is
extremely difficult to simulate with conventional EM solvers
due to meshing difficulties and the multiscale nature of the
problem. In this paper, we develop a hybrid distorted Born
approximation and 3-D mixed ordered stabilized biconjugate
gradient fast Fourier transform (DBA-BCGS-FFT) method to
simulate the very challenging 2-D, 2-D-axisymmetric, and 3-D
hydraulic fracture models under both open and cased borehole
environments. Numerical examples show that this method has
orders of magnitude higher efficiency than the finite
element method. The capabilities of the DBA-BCGS-FFT method
for the induction tool fracture mapping are demonstrated by
comparing with laboratory experimental results and other
reference results.},
Doi = {10.1109/TGRS.2016.2620482},
Key = {fds341075}
}
@article{fds331504,
Author = {Li, J and He, B and Li, L and Zhang, A and Liu, J and Liu,
QH},
Title = {Capacitor-loaded circularly polarized annular-ring slotted
microstrip patch antenna},
Journal = {Isape 2016 Proceedings of the 11th International Symposium
on Antennas, Propagation and Em Theory},
Pages = {13-15},
Publisher = {IEEE},
Year = {2017},
Month = {January},
ISBN = {9781509047420},
url = {http://dx.doi.org/10.1109/ISAPE.2016.7833897},
Abstract = {This paper studies a simple and novel annular-ring slotted
microstrip patch antenna loaded by a surface mount chip
capacitor for circularly polarized (CP) radiation. By
connecting the capacitor with a proper value across the
annular-ring slot at an appropriate position, the
fundamental resonant mode of the microstrip patch antenna
can be degenerated into two orthogonal modes with equal
amplitude and quadrature phase. Hence, CP radiation can be
obtained. An antenna prototype was fabricated and measured.
The simulation and measurement results validate that the
proposed antenna has excellent CP characteristics at the
resonant frequency.},
Doi = {10.1109/ISAPE.2016.7833897},
Key = {fds331504}
}
@article{fds331503,
Author = {Li, J and Li, L and Zhang, A and Liu, J and Liu, QH},
Title = {Wideband two bowtie dipole array antenna integrated with a
tapered balun},
Journal = {Isape 2016 Proceedings of the 11th International Symposium
on Antennas, Propagation and Em Theory},
Pages = {16-18},
Publisher = {IEEE},
Year = {2017},
Month = {January},
ISBN = {9781509047420},
url = {http://dx.doi.org/10.1109/ISAPE.2016.7833908},
Abstract = {This paper presents a wideband antenna consisting of two
series-fed fan-shaped bowtie dipole antenna elements and an
integrated tapered balun for through-the-wall imaging radar
(TWIR) applications. The two fan-shaped bowtie dipole
antenna elements with different radii and same flare angle
are connected using a coplanar stripline and backed by a
ground reflector. The balun realized by a tapered microstrip
line and a slot line is used to feed the antenna. The
proposed antenna has been numerically investigated, which
shows that a 10-dB impedance bandwidth of 85.9% ranging from
1.38 to 3.46 GHz is attained. The overall size of the
proposed antenna is 1.2λ × 0.8λ. The radiation patterns
are roughly stable over the operating bandwidth with nearly
endfire characteristic.},
Doi = {10.1109/ISAPE.2016.7833908},
Key = {fds331503}
}
@article{fds341198,
Author = {Zheng, JB and Liao, GS and Liu, QH},
Title = {PCFCRD for multicomponent LFM signals analysis},
Journal = {Electronics Letters},
Volume = {53},
Number = {1},
Pages = {31-32},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1049/el.2016.3074},
Abstract = {A novel extension of the cubic phase function (CPF), known
as the parameterised centroid frequency-chirp rate
distribution (PCFCRD), is proposed for multicomponent linear
frequency modulated signals analysis. The PCFCRD is coherent
and introduces a constant delay to reduce the noise
correlation. Mathematic analysis and numerical simulations
demonstrate that, compared with the coherent integrated CPF,
the PCFCRD can obtain a higher anti-noise
performance.},
Doi = {10.1049/el.2016.3074},
Key = {fds341198}
}
@article{fds340832,
Author = {Li, J and Wang, C and Zhang, A and Joines, WT and Liu,
QH},
Title = {Microstrip-line-fed reactively loaded circularly polarized
annular-ring slot antenna},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {31},
Number = {1},
Pages = {101-110},
Publisher = {Informa UK Limited},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1080/09205071.2016.1277790},
Abstract = {A simple and novel reactively loaded annular-ring slot
antenna (ARSA) fed by a microstrip line is proposed and
investigated for circularly polarized (CP) radiation. An
appropriate reactive component, i.e. lumped
capacitor/inductor, is introduced across the annular-ring
slot at a proper position to achieve CP radiation. To
validate the design concept, a capacitively loaded ARSA
(CL-ARSA) and an inductively loaded ARSA (IL-ARSA) were
implemented and measured, showing that good CP
characteristics have been attained. The measured 3-dB axial
ratio (AR) bandwidths for the CL-ARSA and IL-ARSA are 5.5
and 6.7%, respectively.},
Doi = {10.1080/09205071.2016.1277790},
Key = {fds340832}
}
@article{fds341201,
Author = {Li, W and Xia, Z and You, B and Liu, Y and Liu, QH},
Title = {Dual-Polarized H-Shaped Printed Slot Antenna},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {1484-1487},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1109/LAWP.2016.2646805},
Abstract = {A new colocated dual-polarized printed slot antenna with
high port isolation is presented. This antenna has an
H-shaped slot consisting of a wide main slot with a coplanar
waveguide feedline and two side slots with a microstrip
feedline. Electric field analysis indicates that the field
antinodes of the main slot for port 1 are located at the
main slot terminals, whereas those of two side slots for
port 2 are in the middle of themselves. In addition, an
additional conductor strip of microstrip size across the
nonfed side slot is introduced to improve the symmetry of
the antenna structure and then enhance the port isolation.
An antenna prototype designed in WLAN 2.4-GHz band is
fabricated. Experimental results show that this antenna can
achieve 17% relative bandwidth and 32 dB isolation over this
band. Meanwhile, the copolarization field level in the
maximum radiation direction is 25 dB larger than the cross
polarization.},
Doi = {10.1109/LAWP.2016.2646805},
Key = {fds341201}
}
@article{fds341200,
Author = {Ren, Y and Huang, WF and Niu, J and Liu, QH},
Title = {A Hybrid Solver Based on Domain Decomposition Method for the
Composite Scattering in Layered Medium},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {420-423},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1109/LAWP.2016.2582149},
Abstract = {In the framework of domain decomposition method, we present
a novel hybrid solver for accurate electromagnetic
simulations of composite objects in layered medium (LM).
This hybrid solver combines the surface integral equation
method and the finite element method to effectively minimize
the simulation domain, where the effect of inhomogeneous
background is involved by the LM Green's functions, and the
field transmission between neighboring subdomains is
realized by the Riemann solver. Numerical results are given
to validate the proposed solver.},
Doi = {10.1109/LAWP.2016.2582149},
Key = {fds341200}
}
@article{fds341203,
Author = {Zhuang, M and Sun, Q and Yuan, M and Deng, C and Liu,
QH},
Title = {Piezoelectric transducer modeling in anisotropic
media},
Journal = {13th International Conference on Theoretical and
Computational Acoustics, Ictca 2017},
Volume = {2017-July},
Pages = {213},
Year = {2017},
Month = {January},
ISBN = {9783200052109},
Key = {fds341203}
}
@article{fds341199,
Author = {Huang, X and Liu, Y and You, P and Zhang, M and Liu,
QH},
Title = {Fast Linear Array Synthesis Including Coupling Effects
Utilizing Iterative FFT via Least-Squares Active Element
Pattern Expansion},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {16},
Pages = {804-807},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1109/LAWP.2016.2604570},
Abstract = {A novel method incorporating the least-squares active
element pattern expansion (LS-AEPE) into the iterative
Fourier transform (IFT) procedure is presented to
efficiently synthesize linear arrays including mutual
coupling and platform effects. The proposed method has
better pattern synthesis accuracy than the original IFT, and
is much faster than the combination of LS-AEPE and the
genetic algorithm. Numerical examples are given for
synthesizing the patterns of two microstrip antenna arrays
mounted on inhomogeneous platforms. Synthesis results show
the effectiveness and advantages of the proposed
method.},
Doi = {10.1109/LAWP.2016.2604570},
Key = {fds341199}
}
@article{fds331505,
Author = {Zhu, J and Cheng, J and Zhang, L and Liu, QH},
Title = {Modeling of 2D graphene material for plasmonic hybrid
waveguide with enhanced near-infrared modulation},
Journal = {Materials Letters},
Volume = {186},
Pages = {53-56},
Publisher = {Elsevier BV},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1016/j.matlet.2016.09.108},
Abstract = {Modulating near-infrared signals is critical for high
density optical interconnects. In order to achieve enhanced
modulation effects, we design a near-infrared modulator in
combination with a gold nanostripe waveguide and graphene.
Conventional assumption of isotropic permittivities for
graphene leads to exaggeration of light absorption at the
so-called “epsilon-near-zero” point and extreme
overestimation of modulation efficiency, and the anisotropic
permittivities assumption faces problems for thickness
definition and lower computational efficiency. Therefore, we
treat graphene as a 2D conductive surface in the simulation
to solve these problems, and investigate the plasmonic
effects on modulation enhancement and the trade-off on the
modulation efficiency versus the insertion loss. Our method
is promising for the design of advanced optical devices
based on 2D materials.},
Doi = {10.1016/j.matlet.2016.09.108},
Key = {fds331505}
}
@article{fds341202,
Author = {Hong, R and Li, S and Zhang, J and Zhang, Y and Liu, N and Yu, Z and Liu,
QH},
Title = {3-D MRI-based electrical properties tomography using the
volume integral equation method},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {65},
Number = {12},
Pages = {4802-4811},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1109/TMTT.2017.2725830},
Abstract = {MRI-based electrical properties tomography, a noninvasive
technique for characterizing electrical conductivity and
permittivity of human tissues, has been developed for the
diagnosis of cancer and specific absorption rate
quantification since 1991, based on the distortion of radio
frequency magnetic field in MRI. For high-contrast tissues,
the volume integral equation (VIE) method is appropriate to
reconstruct the electrical properties because of its
flexibility in handling complex high-contrast inhomogeneous
scatterers without approximations. In this paper, the
variational Born iterative method is used to solve the
nonlinear inverse problem of the reconstruction of
dielectric contrast function. To improve the computation
efficiency, the stabilized biconjugate-gradient fast Fourier
transform method and the conjugate-gradient fast Fourier
transform method are incorporated in the forward and inverse
problems of the VIE, respectively. The numerical results
have demonstrated that the inversion method based on the
positive rotating magnetic field of MRI is capable of
reconstructing high-spatial-resolution electrical properties
mapping of inhomogeneous human tissues.},
Doi = {10.1109/TMTT.2017.2725830},
Key = {fds341202}
}
@article{fds341076,
Author = {Chen, Y and Ye, L and Zhuo, J and Liu, Y and Zhang, L and Zhang, M and Liu,
QH},
Title = {Frequency Reconfigurable Circular Patch Antenna with an
Arc-Shaped Slot Ground Controlled by PIN
Diodes},
Journal = {International Journal of Antennas and Propagation},
Volume = {2017},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1155/2017/7081978},
Abstract = {In this paper, a compact frequency reconfigurable circular
patch antenna with an arc-shaped slot loaded in the ground
layer is proposed for multiband wireless communication
applications. By controlling the ON/OFF states of the five
PIN diodes mounted on the arc-shaped slot, the effective
length of the arc-shaped slot and the effective length of
antennas current are changed, and accordingly six-frequency
band reconfiguration can be achieved. The simulated and
measured results show that the antenna can operate from 1.82
GHz to 2.46 GHz, which is located in DCS1800 (1.71-1.88
GHz), UMTS (2.11-2.20 GHz), WiBro (2.3-2.4 GHz), and
Bluetooth (2.4-2.48 GHz) frequency bands and so forth.
Compared to the common rectangular slot circular patch
antenna, the proposed arc-shaped slot circular patch antenna
not only has a better rotational symmetry with the circular
patch and substrate but also has more compact size. For the
given operating frequency at 1.82 GHz, over 55% area
reduction is achieved in this design with respect to the
common design with rectangular slot. Since the promising
frequency reconfiguration, this antenna may have potential
applications in modern multiband and multifunctional mobile
communication systems.},
Doi = {10.1155/2017/7081978},
Key = {fds341076}
}
@article{fds341077,
Author = {Xu, KD and Xu, H and Liu, Y and Ai, J and Liu, QH},
Title = {Short- and open-stub loaded spiral resonator and its
application in planar microstrip filters},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {11},
Number = {3},
Pages = {363-369},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1049/iet-map.2016.0253},
Abstract = {A novel short- and open-stub loaded spiral resonator
(SOSL-SR) is presented and analysed by the odd- and
even-mode method to obtain three controllable resonant
modes. Therefore, a triple-mode bandpass filter (BPF) has
been designed with good frequency selectivity based on the
proposed SOSL-SR. Then, by dividing these three resonant
modes into two passbands or stopbands, a dual-band BPF and a
dual-band bandstop filter using the proposed SOSL-SR have
been demonstrated. Because of the spiral structure, the
sizes of these three designed microstrip filters are reduced
significantly. Good agreement between simulated and measured
results validates the design concept.},
Doi = {10.1049/iet-map.2016.0253},
Key = {fds341077}
}
@article{fds340950,
Author = {Deng, C and Luo, M and Yuan, M and Zhao, B and Zhuang, M and Liu,
QH},
Title = {The Auxiliary Differential Equations Perfectly Matched
Layers Based on the Hybrid SETD and PSTD Algorithms for
Acoustic Waves},
Journal = {Journal of Computational Acoustics},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1142/S0218396X1750031X},
Abstract = {The perfectly matched layer (PML) absorbing boundary
condition has been proven to absorb body waves and surface
waves very efficiently at non-grazing incidence. However,
the traditional PML would generate large spurious
reflections at grazing incidence, for example, when the
sources are located near the truncating boundary and the
receivers are at a large offset. In this paper, a new PML
implementation is presented for the boundary truncation in
three-dimensional spectral element time domain (SETD) for
solving acoustic wave equations. This method utilizes
pseudospectral time-domain (PSTD) method to solve
first-order auxiliary differential equations (ADEs), which
is more straightforward than that in the classical FEM
framework.},
Doi = {10.1142/S0218396X1750031X},
Key = {fds340950}
}
@article{fds340813,
Author = {Zhan, Q and Sun, Q and Ren, Q and Mao, Y and Fang, Y and Liu,
QH},
Title = {Discontinuous galerkin algorithm for elastic wave scattering
by arbitrary discrete fractures},
Journal = {13th International Conference on Theoretical and
Computational Acoustics, Ictca 2017},
Volume = {2017-July},
Pages = {209},
Year = {2017},
Month = {January},
ISBN = {9783200052109},
Key = {fds340813}
}
@article{fds340851,
Author = {Ye, L and Xiao, Y and Liu, N and Song, Z and Zhang, W and Liu,
QH},
Title = {Plasmonic waveguide with folded stubs for highly confined
terahertz propagation and concentration.},
Journal = {Optics Express},
Volume = {25},
Number = {2},
Pages = {898-906},
Year = {2017},
Month = {January},
url = {http://dx.doi.org/10.1364/oe.25.000898},
Abstract = {We proposed a novel planar terahertz (THz) plasmonic
waveguide with folded stub arrays to achieve excellent
terahertz propagation performance with tight field
confinement and compact size based on the concept of spoof
surface plasmon polaritons (spoof SPPs). It is found that
the waveguide propagation characteristics can be directly
manipulated by increasing the length of the folded stubs
without increasing its lateral dimension, which exhibits
much lower asymptotic frequency of the dispersion relation
and even tighter terahertz field confinement than
conventional plasmonic waveguides with rectangular stub
arrays. Based on this waveguiding scheme, a terahertz
concentrator with gradual step-length folded stubs is
proposed to achieve high terahertz field enhancement, and an
enhancement factor greater than 20 is demonstrated. This
work offers a new perspective on very confined terahertz
propagation and concentration, which may have promising
potential applications in various integrated terahertz
plasmonic circuits and devices, terahertz sensing and
terahertz nonlinear optics.},
Doi = {10.1364/oe.25.000898},
Key = {fds340851}
}
@article{fds341204,
Author = {Liu, J and He, B and Chen, Q and Liu, H and Li, J and Xiong, Q and Zhang, X and Yang, S and Yue, G and Liu, QH},
Title = {Plasma electrochemical synthesis of cuprous oxide
nanoparticles and their visible-light photocatalytic
effect},
Journal = {Electrochimica Acta},
Volume = {222},
Pages = {1677-1681},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1016/j.electacta.2016.11.158},
Abstract = {A plasma electrochemical method is used to synthesize
cuprous oxide nanoparticles (Cu2O NPs). In this system, a
gaseous discharge plasma is used to replace the usual solid
electrode in a conventional electrodeposition, and Cu2+ ions
are released from anodic dissolution and take a form of
Cu2(OH)2+ in the solution. The Cu2(OH)2+ moves to the
cathode reaction zone and then is reduced to the Cu2O
monomer by reductants generated from the plasma-liquid
interactions. Consequently, Cu2O NPs are formed in the
solution by the combination of Cu2O monomers. The results
indicate that the morphology and Cu valence in the
nanoparticles are tuned by the added surfactant of glucose
or ascorbic acid. Moreover, the Cu2O NPs synthesized with a
suitable concentration of ascorbic acid demonstrate strong
visible light photocatalytic activity on the methyl orange
degradation.},
Doi = {10.1016/j.electacta.2016.11.158},
Key = {fds341204}
}
@article{fds323084,
Author = {Shi, L and Zhou, Y and Wang, JM and Zhuang, M and Liu, N and Liu,
QH},
Title = {Spectral element method for elastic and acoustic waves in
frequency domain},
Journal = {Journal of Computational Physics},
Volume = {327},
Pages = {19-38},
Publisher = {Elsevier BV},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1016/j.jcp.2016.09.036},
Abstract = {Numerical techniques in time domain are widespread in
seismic and acoustic modeling. In some applications,
however, frequency-domain techniques can be advantageous
over the time-domain approach when narrow band results are
desired, especially if multiple sources can be handled more
conveniently in the frequency domain. Moreover, the medium
attenuation effects can be more accurately and conveniently
modeled in the frequency domain. In this paper, we present a
spectral-element method (SEM) in frequency domain to
simulate elastic and acoustic waves in anisotropic,
heterogeneous, and lossy media. The SEM is based upon the
finite-element framework and has exponential convergence
because of the use of GLL basis functions. The anisotropic
perfectly matched layer is employed to truncate the boundary
for unbounded problems. Compared with the conventional
finite-element method, the number of unknowns in the SEM is
significantly reduced, and higher order accuracy is obtained
due to its spectral accuracy. To account for the
acoustic-solid interaction, the domain decomposition method
(DDM) based upon the discontinuous Galerkin spectral-element
method is proposed. Numerical experiments show the proposed
method can be an efficient alternative for accurate
calculation of elastic and acoustic waves in frequency
domain.},
Doi = {10.1016/j.jcp.2016.09.036},
Key = {fds323084}
}
@article{fds323080,
Author = {Zhu, C and Liu, L and Song, Z and Liu, QH},
Title = {Optimized invisibility cloaks from the Logarithm conformal
mapping.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {38443},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1038/srep38443},
Abstract = {Invisibility cloaks designed from the coordinate
transformation method have attracted increasing interest
recently. Conformal transformation optics scheme leads to
cloaks that possess isotopic media, thus provides a
prospective way to facilitate easier realization. Reducing
the maximum value of the refractive index required by the
cloaks is very important in practical imple- mentation. This
letter studies on how the parameters in the logarithm
conformal mapping control the cloaking effect. The optimized
invisibility cloaks are designed. The maximum values of the
refractive index required from the first kind and the second
kind of logarithm conformal mappings are reduced to 9.779
and 12.936, respectively.},
Doi = {10.1038/srep38443},
Key = {fds323080}
}
@article{fds323081,
Author = {Ye, L and Xiao, Y and Liu, Y and Zhang, L and Cai, G and Liu,
QH},
Title = {Strongly Confined Spoof Surface Plasmon Polaritons
Waveguiding Enabled by Planar Staggered Plasmonic
Waveguides.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {38528},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1038/srep38528},
Abstract = {We demonstrate a novel route to achieving highly efficient
and strongly confined spoof surface plasmon polaritons
(SPPs) waveguides at subwavelength scale enabled by planar
staggered plasmonic waveguides (PSPWs). The structure of
these new waveguides consists of an ultrathin metallic strip
with periodic subwavelength staggered double groove arrays
supported by a flexible dielectric substrate, leading to
unique staggered EM coupling and waveguiding phenomenon. The
spoof SPP propagation properties, including dispersion
relations and near field distributions, are numerically
investigated. Furthermore, broadband coplanar waveguide
(CPW) to planar staggered plasmonic waveguide (PSPW)
transitions are designed to achieve smooth momentum matching
and highly efficient spoof SPP mode conversion. By applying
these transitions, a CPW-PSPW-CPW structure is designed,
fabricated and measured to verify the PSPW's propagation
performance at microwave frequencies. The investigation
results show the proposed PSPWs have excellent performance
of deep subwavelength spoof SPPs confinement, long
propagation length and low bend loss, as well as great
design flexibility to engineer the propagation properties by
adjusting their geometry dimensions and material parameters.
Our work opens up a new avenue for development of various
advanced planar integrated plasmonic devices and circuits in
microwave and terahertz regimes.},
Doi = {10.1038/srep38528},
Key = {fds323081}
}
@article{fds323082,
Author = {Liu, J and He, B and Chen, Q and Li, J and Xiong, Q and Yue, G and Zhang, X and Yang, S and Liu, H and Liu, QH},
Title = {Direct synthesis of hydrogen peroxide from plasma-water
interactions.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {38454},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1038/srep38454},
Abstract = {Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) is usually
considered to be an important reagent in green chemistry
since water is the only by-product in H<sub>2</sub>O<sub>2</sub>
involved oxidation reactions. Early studies show that direct
synthesis of H<sub>2</sub>O<sub>2</sub> by plasma-water
interactions is possible, while the factors affecting the
H<sub>2</sub>O<sub>2</sub> production in this method remain
unclear. Herein, we present a study on the
H<sub>2</sub>O<sub>2</sub> synthesis by atmospheric pressure
plasma-water interactions. The results indicate that the
most important factors for the H<sub>2</sub>O<sub>2</sub>
production are the processes taking place at the
plasma-water interface, including sputtering, electric field
induced hydrated ion emission, and evaporation. The
H<sub>2</sub>O<sub>2</sub> production rate reaches
~1200 μmol/h when the liquid cathode is purified water or
an aqueous solution of NaCl with an initial conductivity of
10500 μS cm<sup>-1</sup>.},
Doi = {10.1038/srep38454},
Key = {fds323082}
}
@article{fds323085,
Author = {Zhu, C and Liu, L and Song, Z and Liu, Y and Liu, QH},
Title = {An efficient exact numerical solution for scattering by a
circular cylinder},
Journal = {Ieej Transactions on Electrical and Electronic
Engineering},
Volume = {11},
Pages = {S3-S10},
Publisher = {WILEY},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1002/tee.22319},
Abstract = {An efficient and exact spectral integral method (SIM) for
the general problems of scattering by a circular cylinder is
presented, both for acoustic and electromagnetic cases. Fast
Fourier transform (FFT) and convolution theorem help us to
execute the algorithm efficiently with (O(N log (N)))
computational complexity. The Fourier coefficients of the
integral kernels are computed in a semianalytical way to
accomplish a fast convergence rate with spectral accuracy.
Compared with the method not using the semianalytical forms,
without the increase of the computing and memory abundance,
it saves more than 90% sampling points to achieve about the
same accuracy, and with the same number of sampling points,
several to more than ten orders of magnitude more accuracy
can be achieved. For example, for the tested large
wavenumber case with 2 × 106 wavelengths on the boundary,
only two sampling points per wavelength are required to
achieve a relative error of less than 0.001%. More than 90%
computational time is saved compared with the normal
summation formula of harmonic cylinder expansions. © 2016
Institute of Electrical Engineers of Japan. Published by
John Wiley & Sons, Inc.},
Doi = {10.1002/tee.22319},
Key = {fds323085}
}
@article{fds323083,
Author = {Yang, H and Li, T and Li, N and He, Z and Liu, QH},
Title = {Efficient Stolt Migration for Large Nonuniform Single
Borehole Radar Surveys},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {54},
Number = {12},
Pages = {7250-7260},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1109/TGRS.2016.2598820},
Abstract = {In this paper, the formulation of Stolt migration is
modified for impulse borehole radar imaging in large
nonuniform subsurface scenarios. By applying the nonuniform
fast Fourier transform (FFT) to the acquisition of the
frequency-wavenumber spectrum (FWS), the efficiency of Stolt
migration for nonuniform surveys is improved. First, each
nonuniform exponent basis in Fourier transform is
approximated with a weighted summation of several uniform
exponent bases. Then, the nonuniform samples with the same
uniform exponent basis are accumulated to generate a larger
virtual uniform sample set. The FWS of nonuniform samples is
approximated with the virtual sample set by FFT. Finally,
angular frequency interpolation and inverse FFT are
performed over a sample FWS to reconstruct the reflectivity
map of the imaging area. The selection of approximation
parameters is discussed to make a tradeoff between
approximation error and computational cost. The improved
Stolt migration technique is compared with the conventional
backprojection method and the Kirchhoff migration method on
synthetic data and validated by a single borehole radar
experiment in a subsurface scenario. The results show that
the developed Stolt migration is superior to the
conventional methods in terms of computational cost,
cross-range resolution, and the ability to reconstruct the
targets.},
Doi = {10.1109/TGRS.2016.2598820},
Key = {fds323083}
}
@article{fds341205,
Author = {Liu, N and Cai, G and Ye, L and Liu, QH},
Title = {The Efficient Mixed FEM with the Impedance Transmission
Boundary Condition for Graphene Plasmonic
Waveguides},
Journal = {Journal of Lightwave Technology},
Volume = {34},
Number = {23},
Pages = {5363-5370},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1109/JLT.2016.2613904},
Abstract = {A mixed finite-element method with an impedance transmission
boundary condition (ITBC) is proposed to solve the graphene
plasmonic modes. The new variational formulation combines
the Gauss' law with the transverse components of vectorial
Helmholtz equation and models the field penetration through
a thin graphene sheet by ITBC. The second-order edge-based
vector LT/QN basis functions are applied to expand the
transverse components of the electric field, and the
nodal-based scalar basis functions are employed to
discretize its longitudinal component. Numerical results on
some designed graphene-based waveguides clearly demonstrate
that the proposed method is efficient and accurate for the
determination of graphene plasmonic modes.},
Doi = {10.1109/JLT.2016.2613904},
Key = {fds341205}
}
@article{fds341206,
Author = {Cai, QM and Zhao, YW and Huang, WF and Zheng, YT and Zhang, ZP and Nie, ZP and Liu, QH},
Title = {Volume Surface Integral Equation Method Based on Higher
Order Hierarchical Vector Basis Functions for EM Scattering
and Radiation From Composite Metallic and Dielectric
Structures},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {12},
Pages = {5359-5372},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1109/TAP.2016.2621018},
Abstract = {This paper presents a novel Galerkin-type method of moments
solution of the volume surface integral equation (VSIE),
which is developed for the analysis of electromagnetic
scattering and radiation from composite metallic and
dielectric structures. Our new scheme utilizes curved
tetrahedral elements and curved triangular patches for
geometric modeling, and the associated higher order
hierarchical vector (HOHV) basis functions for
volume/surface current modeling. In contrast to the previous
studies on higher order VSIE, our scheme, which is reported
for the first time in VSIE, is much more flexible. In
comparison with the conventional low-order scheme, our
scheme requires much less memory and computational time for
the same accuracy level. Numerical results are provided to
demonstrate the accuracy, efficiency, and flexibility of our
scheme.},
Doi = {10.1109/TAP.2016.2621018},
Key = {fds341206}
}
@article{fds341108,
Author = {Zhang, L and Zhang, S and Liu, Y and Liu, QH},
Title = {Broadband Tunable Frequency Selective Surface for Steerable
Antenna Applications},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {12},
Pages = {5496-5500},
Year = {2016},
Month = {December},
url = {http://dx.doi.org/10.1109/TAP.2016.2621299},
Abstract = {Resonant frequency tunable range is an important character
for active frequency selective surfaces (AFSSs), especially
when building electronically steerable antennas based on
AFSS. In this communication, a broadband tunable bandpass
AFSS is presented. The tunable ability is achieved by the
varactors mounted on the surface. The proposed design has
zigzag resonant current flows through multiple unit cells.
Thus, the magnetic field coupling between unit cells is
enhanced and the resonant frequency tunable range is
extended. The measured resonant frequency tunable range is
from 935 MHz to 2.405 GHz. Another advantage of this design
is that no additional bias grid is required. Furthermore,
this design has stable response under different angles of
incidence because it has subwavelength dimensions.},
Doi = {10.1109/TAP.2016.2621299},
Key = {fds341108}
}
@article{fds340814,
Author = {Yang, X and Chen, Y and Ye, L and Wang, M and Yu, M and Liu,
QH},
Title = {Frequency reconfigurable circular patch antenna using PIN
diodes},
Journal = {9th International Conference on Microwave and Millimeter
Wave Technology, Icmmt 2016 Proceedings},
Volume = {2},
Pages = {606-608},
Publisher = {IEEE},
Year = {2016},
Month = {November},
ISBN = {9781467389815},
url = {http://dx.doi.org/10.1109/ICMMT.2016.7762382},
Abstract = {A frequency reconfigurable circular patch antenna using
PIN-diodes is proposed in this paper. This antenna consists
of a circular patch with an arc-shaped slot in the ground
layer. Three PIN diodes are mounted on the arc-shaped slot
to achieve frequency reconfiguration. Full wave simulation
and experimental testing are carried out to characterize the
antenna's radiation performance. The investigate results
show that six different frequency bands can be switched
while keeping similar radiation patterns by controlling the
states of the PIN switches. Since the promising frequency
reconfiguration, the proposed antenna might have potential
applications in future multi-functional wireless
systems.},
Doi = {10.1109/ICMMT.2016.7762382},
Key = {fds340814}
}
@article{fds341207,
Author = {Liang, Y and Guo, LX and Tong, MS and Wu, ZS and Liu,
QH},
Title = {Research of influences from typical scene parameters on
target and rough surface composite electromagnetic
scattering characteristics},
Journal = {2016 Progress in Electromagnetics Research Symposium, Piers
2016 Proceedings},
Pages = {2474-2477},
Year = {2016},
Month = {November},
ISBN = {9781509060931},
url = {http://dx.doi.org/10.1109/PIERS.2016.7735019},
Abstract = {Some studies of the influences from typical scene (target,
rough surface) parameters on the target and rough surface
composite electromagnetic scattering characteristics are
carrying out. The target and rough surface with specific
type and spectrum cases are considered. The composite
scattering integral equations are built. The numerical
hybrid strategies, such as the Propagation-Inside-Layer-Expansion
(PILE) combined with the Forward-Backward Method (FBM)
scheme, etc., are applied. The influence from different
target parameters, such as, size, depth, etc., to the
coupling inductions is investigated. The influence from
different rough surface parameters, such as rms height,
correlation length etc., to the composite scattering is
implemented. The experiential and prediction models between
typical scattering phenomenon and coupling interaction
mechansium under different parameters can be built and
analyzed. The presented studies will make considerable sense
to the fields of electromagnetics, remote sensing, optics,
radar surveillance, target recognition, material science,
etc.},
Doi = {10.1109/PIERS.2016.7735019},
Key = {fds341207}
}
@article{fds323087,
Author = {Liu, L and Zhang, J and Zhao, X and Mao, Z and Liu, N and Zhang, Y and Liu,
QH},
Title = {Interaction between charged nanoparticles and vesicles:
coarse-grained molecular dynamics simulations.},
Journal = {Physical Chemistry Chemical Physics : Pccp},
Volume = {18},
Number = {46},
Pages = {31946-31957},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1039/c6cp05998h},
Abstract = {An enhanced understanding of the interactions between
charged nanoparticles (CNPs) and a curved vesicle membrane
may have important implications for the design of
nanocarrier agents and drug delivery systems. In this work,
coarse-grained molecular dynamics (CGMD) simulations of the
CNPs with vesicles were performed to evaluate the effects of
hydrophobicity, surface charge density and distribution on
the curved vesicle membrane. The simulations reveal that
there exist four distinct modes (insertion, repulsion,
adhesion, and penetration) in the CNP-vesicle interaction.
In contrast to previous studies on a planar membrane, the
interactions of CNPs and a curved vesicle membrane show some
novel properties. CNPs with low surface charge density (or
neutral ones) can penetrate into the interior of the vesicle
membrane more easily because of the increased membrane
tension. The asymmetry between two leaflets of the membrane
induces different interaction strengths of the negatively
CNPs with the outer and inner leaflets. After penetration,
the negatively CNPs prefer to stay close to the inner
leaflet inside the vesicle where CNPs have stronger
interactions with their surroundings. In the present work,
we analyze the detailed mechanism of CNP's spontaneous
penetration into vesicles, which is rarely mentioned in
previous simulations. Moreover, we found that the negatively
CNPs with the same surface charge density but different
distribution result in different modes: the homogeneous mode
is more likely to adsorb on the vesicle surface while the
inhomogeneous mode tends to be more penetrable. In addition,
the flip-flop phenomenon of the lipid membrane and the
exchanging of water in or out of the vesicle were observed
during penetration. Our results demonstrate that the
electrostatic effect plays an essential role in the
interaction between CNPs and vesicles. These findings
suggest a way of controlling the CNP-vesicle interaction by
coupling the hydrophobic properties, surface charge density
and distribution of CNPs to enhance the probability of CNP's
penetration into vesicles.},
Doi = {10.1039/c6cp05998h},
Key = {fds323087}
}
@article{fds323088,
Author = {Xu, KD and Bai, YC and Zhu, CH and Liu, YH and Ren, Y and Liu,
QH},
Title = {Compact bandpass filters using multistub loaded spiral
short-ended resonator},
Journal = {Microwave and Optical Technology Letters},
Volume = {58},
Number = {11},
Pages = {2738-2741},
Publisher = {WILEY},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1002/mop.30135},
Abstract = {A novel compact stub-loaded short-ended spiral resonator is
presented for the first time. The characteristics of the
proposed spiral resonator are deduced by even- and odd-mode
analysis method. In addition to miniaturization and high
selectivity, the bandpass filter (BPF) utilizing the
short-ended spiral resonator is found to have a tunable
bandwidth. On the basis of the proposed resonator, two
practical BPFs operating at 2.4 GHz with a 3-dB bandwidth of
about 20.8 and 37.5% respectively for WLAN application is
designed and fabricated. Good agreement between the
simulated and measured results is provided to validate the
designed concept.© 2016 Wiley Periodicals, Inc. Microwave
Opt Technol Lett 58:2738–2741, 2016.},
Doi = {10.1002/mop.30135},
Key = {fds323088}
}
@article{fds323089,
Author = {Hong, D and Huang, WF and Liu, QH},
Title = {Radiation of Arbitrary Magnetic Dipoles in a Cylindrically
Layered Anisotropic Medium for Well-Logging
Applications},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {54},
Number = {11},
Pages = {6362-6370},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1109/TGRS.2016.2582535},
Abstract = {We present a set of stable and efficient formulas to compute
the electromagnetic radiation of arbitrary magnetic dipoles
in a cylindrically layered anisotropic medium. This set of
formulas is derived on the basis of the generalized
reflection and transmission coefficients. By expressing our
new formulas by the ratios of Bessel or Hankel functions,
rather than directly by these special functions, the
notorious overflow problem for numerical computation is
successfully obviated. Our formulas can be easily
implemented for any number of layers, as well as for
arbitrary locations and orientations of the transmitter and
the receiver. Numerical experiments have demonstrated their
correctness and stability. They are then utilized to
investigate the influence of the eccentricity distance, the
eccentricity angle, and the formation anisotropy on the
response of a multicomponent induction logging
tool.},
Doi = {10.1109/TGRS.2016.2582535},
Key = {fds323089}
}
@article{fds323090,
Author = {Liu, J and Jia, Y and Kong, L and Yang, X and Liu, QH},
Title = {Sign-coherence-factor-based suppression for grating lobes in
through-wall radar imaging},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {13},
Number = {11},
Pages = {1681-1685},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1109/LGRS.2016.2603982},
Abstract = {A sparse and uniform multiple-input-multiple-output array is
generally utilized in through-wall radar to implement
real-time imaging of moving targets. However, the array
sparsity with the interelement spacing much bigger than half
a wavelength gives rise to grating lobe interference
smearing the images. In order to enhance the
signal-to-interference ratio, this letter introduces the
sign coherence factor (SCF) to weigh through-wall images to
suppress the grating lobes. The SCF is first proposed in
medical ultrasound imaging and directly reflects the
coherence of sign bits of all the transmit-receive channels
in each pixel. Since the SCF calculated only by the sign
bits, it has the smallest amount of computations compared
with two other weighing factors, namely, the coherence
factor (CF) and the phase coherence factor (PCF), which have
been applied to through-wall imaging already. Moreover, the
SCF has comparable performance in suppressing grating lobes
with the PCF, much better than the CF. These two advantages
make the SCF the most suitable for real-time imaging of
moving targets. The experimental results with a
two-transmitting eight-receiving stepped-frequency
continuous-wave through-wall radar verifies the excellent
performance of the SCF.},
Doi = {10.1109/LGRS.2016.2603982},
Key = {fds323090}
}
@article{fds323091,
Author = {Jia, Y and Yu, Z and Dai, J and Liu, QH},
Title = {Fast Simulation of Scattering Problem for Magnetodielectric
Materials with General Anisotropy in Layered
Media},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {11},
Pages = {4785-4793},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1109/TAP.2016.2600745},
Abstract = {In this paper, the mixed-order stabilized biconjugate
gradient fast Fourier transform (mixed-order BCGS-FFT)
method is presented to solve the scattering problem of
magnetodielectric materials with general anisotropy in
layered media. While the volumetric roof-top functions are
used as the testing functions for the coupled field volume
integral equation and the basis functions for flux
densities, the second-order curl conforming basis functions
are applied to expand the vector potentials with the aim of
both preserving the continuity of their tangential
components and avoiding the zero terms that might otherwise
be caused by the divergence operator. The layered medium
Green's function (LMGF) is efficiently evaluated through the
recursive matrix method along with an interpolation
technique. Several numerical experiments are presented to
demonstrate the high accuracy and efficiency of the method.
Different from the previously published works that aim to
solve the similar problem, the new contribution of this work
is to extend the mixed-order BCGS-FFT method to accommodate
the layered background medium. Therefore, the 3-D FFT
acceleration for integral kernels associated with the LMGF
as well as the interpolation technique has been implemented
and combined with the mixed-order BCGS-FFT
method.},
Doi = {10.1109/TAP.2016.2600745},
Key = {fds323091}
}
@article{fds323110,
Author = {Li, J and Guo, J and He, B and Zhang, A and Liu, QH},
Title = {Tri-Band CPW-Fed Stub-Loaded Slot Antenna Design for
WLAN/WiMAX Applications},
Journal = {Frequenz},
Volume = {70},
Number = {11-12},
Pages = {521-526},
Publisher = {WALTER DE GRUYTER GMBH},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1515/freq-2015-0261},
Abstract = {A novel uniplanar CPW-fed tri-band stub-loaded slot antenna
is proposed for wireless local area network (WLAN) and
worldwide interoperability for microwave access (WiMAX)
applications. Dual resonant modes were effectively excited
in the upper band by using two identical pairs of slot stubs
and parasitic slots symmetrically along the arms of a
traditional CPW-fed slot dipole, achieving a much wider
bandwidth. The middle band was realized by the fundamental
mode of the slot dipole. To obtain the lower band, two
identical inverted-L-shaped open-ended slots were
symmetrically etched in the ground plane. A prototype was
fabricated and measured, showing that tri-band operation
with 10-dB return loss bandwidths of 150 MHz from 2.375 to
2.525GHz, 725 MHz from 3.075 to 3.8GHz, and 1.9GHz from 5.0
to 6.9GHz has been achieved. Details of the antenna design
as well as the measured and simulated results are presented
and discussed.},
Doi = {10.1515/freq-2015-0261},
Key = {fds323110}
}
@article{fds341208,
Author = {Liu, H and Zhang, Y and Chen, Q and Han, F and Liu, QH},
Title = {Reverse-time migration and full waveform inversion applied
to a stationary MIMO GPR system},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {2016-November},
Pages = {7446-7449},
Year = {2016},
Month = {November},
ISBN = {9781509033324},
url = {http://dx.doi.org/10.1109/IGARSS.2016.7730942},
Abstract = {This paper presents a multi-input and multi-output (MIMO)
ground penetrating radar (GPR) system, which is going to be
launched to the moon for imaging shallow regolith structures
and estimating the dielectric properties. This system, as an
important part of China' Chang-E 5 lunar exploration
mission, employs twelve off-ground Vivaldi antennas as
transmitters/receivers, and works in a stationary mode. A
reverse-time migration algorithm is developed to process the
MIMO GPR dataset for obtaining a high-resolution image of
the subsurface objects. The results of a laboratory
experiment on a volcanic ash pit demonstrate that the upper
and lower interfaces of a marble slab of 3 cm thickness
buried at a depth up to 2 m can be clearly imaged. A full
waveform inversion algorithm based on Born iterative method
is applied to invert the dielectric properties of the
subsurface objects. The preliminary results of a numerical
experiment demonstrate that the dielectric permittivity of a
subsurface cubic object can be accurately obtained using the
MIMO GPR dataset at only six discrete frequencies.},
Doi = {10.1109/IGARSS.2016.7730942},
Key = {fds341208}
}
@article{fds331506,
Author = {Liu, H and Koyama, C and Zhu, J and Liu, Q and Sato,
M},
Title = {Post-earthquake damage inspection of wood-frame buildings by
a polarimetric GB-SAR system},
Journal = {Remote Sensing},
Volume = {8},
Number = {11},
Pages = {935-935},
Publisher = {MDPI AG},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.3390/rs8110935},
Abstract = {Structural damage inspection after an earthquake is
essential for safety assessment of the affected wood-frame
buildings and for making knowledgeable decision regarding
their repair, renovation, or replacement. We present a
polarimetric radar system for sensing the concealed
wood-frames damaged by earthquakes. This system employs an
antenna array consisting of four linearly polarized Vivaldi
antennas recording full-polarimetric radar echoes in an
ultra-wideband ranging from 1 to 20 GHz. The detailed design
of the system and the signal processing algorithms for
high-resolution 3D imaging are introduced. We conducted a
number of surveys on damaged wooden wall specimens in
laboratory. The experiment results indicate that the
high-frequency radar waves can penetrate the wooden walls.
Deformations of wooden structures (about 2 cm displacement)
inside the wall, as well as the concealed small metal nails
(about 3 mm in diameter and less than 2 cm in length) and
bolts can be clearly imaged. The shape and orientation of
the wooden members have shown a great sensitivity to the
radar polarization. It is concluded that radar polarimetry
can provide much richer information on the condition of
concealed building structures than the conventional
single-polarization subsurface penetrating
radar.},
Doi = {10.3390/rs8110935},
Key = {fds331506}
}
@article{fds330593,
Author = {Li, J and Zhang, A and Joines, WT and Liu, QH},
Title = {A miniaturized circularly polarized microstrip antenna with
bandwidth enhancement},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {41-42},
Publisher = {IEEE},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7695729},
Abstract = {A miniaturized single-feed cross-aperture coupled
right-handed circularly polarized (RHCP) microstrip antenna
with bandwidth enhancement has been presented. The antenna
size miniaturization is achieved by the capacitive loading
offered by the shorting strips and radiating patch, and the
inductive loading induced by the shorting pins. A 0°-90°
microstrip hybrid consisting of a cascade of a Wilkinson
3-dB power divider and a 90° phase shifter is designed to
feed the antenna to significantly improve its bandwidth. The
overall size of the antenna is 50 mm × 50 mm × 6.2 mm
(0.33λ0 × 0.33λ0 × 0.04λ0), exhibiting a global
bandwidth of 12% ranging from 1.88 to 2.12 GHz, where the
return loss is larger than 10 dB, the broadside axial ratio
(AR) is smaller than 3 dB, and the gain is above 0
dBic.},
Doi = {10.1109/APS.2016.7695729},
Key = {fds330593}
}
@article{fds341209,
Author = {Sun, Q and Liu, QH},
Title = {Hybrid DGTD method with FDTD/SETD/FETD},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {233-234},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7695825},
Abstract = {The proposed hybrid DGTD method aims to realize
hybridization of finite difference method with Cartesian
grid, spectral element method with hexahedron elements, and
finite element method with tetrahedron elements in time
domain based on the DG framework. For homogeneous, smoothly
inhomogeneous areas and the perfectly matched layer (PML),
finite difference method is employed to improve the
computational efficiency, as the staircasing approximation
in these areas causes negligible errors and moreover
Cartesian grid discretization results in fewer numbers of
unknowns with respect to a tetrahedron mesh. For irregular
geometries, spectral element or finite element method is
utilized by employing unstructured mesh to eliminate the
staircasing errors. The proposed hybrid DGTD method divide
the original model into FDTD, buffer and SETD/FETD regions.
When the buffer and SETD/FETD regions are with large DoFs,
they can be further split into multiple subdomains to reduce
computational complexity. To improve the time-marching
efficiency, the explicit leapfrog (LF) time integration is
employed for the FDTD and buffer regions, and an implicit
Crank-Nicolson (CN) based time integration is used for the
FETD region. For the SETD region both explicit and implicit
time integration can apply. Thus, a global implicit-explicit
time integration is given for the hybrid method. Numerical
results are shown to demonstrate the accuracy and long-time
stability of the proposed hybrid method.},
Doi = {10.1109/APS.2016.7695825},
Key = {fds341209}
}
@article{fds341210,
Author = {Niu, J and Luo, M and Liu, QH},
Title = {Analyses of optical/electro-optic Kerr effects in third
harmonic compact plasmonics},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {985-986},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7696201},
Abstract = {Starting from the numerical solver based on
boundary-integral spectral element method, the
optical/electro-optic Kerr effects ignored by most previous
study in third harmonic optical nano-structure design are
effectively analyzed. Under strong localized surface
plasmonic resonances, the optical Kerr effect behaves
impactfully for nano-structure's nonlinear characteristics,
while the electro-optic Kerr effect also serves as a
valuable tuning factor.},
Doi = {10.1109/APS.2016.7696201},
Key = {fds341210}
}
@article{fds341211,
Author = {Ren, Y and Niu, J and Huang, W and Liu, QH},
Title = {Hybrid electromagnetic modeling in layered
medium},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {225-226},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7695821},
Abstract = {A hybrid electromagnetic modeling method is introduced for
layered medium application. The simulation domain is
decomposed as several finite element domains and a surface
domain, where the affection of inhomogeneous background is
involved in a dyadic Green's function at the surface. The
proposed method will improve the electromagnetic modeling
flexibility for complex objects in layered medium. A
numerical result is given to validate the proposed hybrid
method.},
Doi = {10.1109/APS.2016.7695821},
Key = {fds341211}
}
@article{fds341212,
Author = {Dai, J and Liu, QH},
Title = {Efficient computation of the em field due to a bipole in
hydrocarbon exploration},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {2111-2112},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7696762},
Abstract = {The numerical mode matching (NMM) method is employed to
compute the electromagnetic field due to a bipole in an
orthogonal-plano-cylindrically layered (OPCL) medium which
consists of materials stratified planarly and layered
cylindrically in the orthogonal directions. We derive the
formulas to compute the excitation vectors due to a bipole
located at any position with an arbitrary orientation.
Finally, the EM field due to a bipole in a five-layer
borehole model is presented to demonstrate the efficiency
and accuracy of this method.},
Doi = {10.1109/APS.2016.7696762},
Key = {fds341212}
}
@article{fds331507,
Author = {Cai, QM and Zhao, YW and Gu, L and Nie, ZP and Liu, QH},
Title = {Electromagnetic scattering by inhomogeneous dielectric and
magnetic scatterers using VIE with a normalization basis
function (NBF) technique},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {1609-1610},
Publisher = {IEEE},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7696511},
Abstract = {A volume integral equations in terms of equivalent volume
electric currents and magnetic currents (JM-VIE) method is
presented for electromagnetic analysis of inhomogeneous
dielectric objects. Higher order geometrical modeling and
curvilinear basis functions (CSWG) defined inside
tetrahedrons are applied for high accuracy and reducing the
unknowns. The equivalent currents are expanded by using the
Full-CSWG functions and the Half-CSWG functions.
Non-conformal discretization can be used in the JM-VIE
method. Besides, the use of a normalization basis function
(NBF) technique in the method reduces the iterative
convergence steps. Numerical results are given to show the
validity of the method.},
Doi = {10.1109/APS.2016.7696511},
Key = {fds331507}
}
@article{fds331508,
Author = {Cai, QM and Zhao, YW and Gu, L and Nie, ZP and Liu, QH},
Title = {Analysis of multi-scale problems from PEC objects by a
discontinuous Galerkin SIE based on higher order
hierarchical vector basis functions},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {1611-1612},
Publisher = {IEEE},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7696512},
Abstract = {A higher order method of moments (MoM) surface integral
equation (SIE) is proposed for analysis of multi-structures
problems from PEC objects with non-conformal mesh. A set of
higher order hierarchical vector basis functions (HOBFs)
based on curved triangular patches are used to attain the
aim of reducing memory and CPU time. Half basis functions
are defined across non-conformal boundary for discretization
independently. The normal continuity of the current across
non-conformal boundary is enforced by an interior penalty
Galerkin condition. Numerical results demonstrate the
validity of the SIE method.},
Doi = {10.1109/APS.2016.7696512},
Key = {fds331508}
}
@article{fds341109,
Author = {Hu, Y and Liu, QH},
Title = {Enhanced electromagnetic measurement with high contrast
nanoparticles injection},
Journal = {2016 Ieee Antennas and Propagation Society International
Symposium, Apsursi 2016 Proceedings},
Pages = {623-624},
Year = {2016},
Month = {October},
ISBN = {9781509028863},
url = {http://dx.doi.org/10.1109/APS.2016.7696020},
Abstract = {Nanoparticles designed with high electric conductivity and
magnetic permeability are injected into oil reservoir to
enhance the tracking of the fluid movement. The injection of
fluid with nanoparticles will displace the original fluid
and change the fluid content in the pore space, thus
changing the electric conductivity and magnetic permeability
distributions in the flooded zone. The movement of
nanoparticles in a porous medium can be modeled by solving
the flow transport equation and the resultant
electromagnetic properties distribution can be calculated by
the effective medium theory. These inhomogeneous
electromagnetic property distributions will induce secondary
electromagnetic fields in the receivers which can be modeled
by Maxwell's equations. For subsurface sensing, in order to
be detected, the secondary fields measured in the receivers
should be above a certain threshold (1% above the primary
fields, an empirical value). By injecting the high contrast
nanoparticles, the conductivity and magnetic permeability of
the flooded zone will be increased, thus increasing the
secondary fields which will be more possibly detected. Also
the detection range of electromagnetic measurements will be
larger. With the technique of coupling of the dynamic fluid
flow and crosswell electromagnetic measurement, we are able
to analyze the detection range of electromagnetic sensing
with high contrast nanoparticle injection.},
Doi = {10.1109/APS.2016.7696020},
Key = {fds341109}
}
@article{fds323116,
Author = {Liu, H and Zhang, Y and Long, Z and Han, F and Liu, QH},
Title = {Reverse time migration for subsurface imaging},
Journal = {2016 Ursi Asia Pacific Radio Science Conference, Ursi Ap
Rasc 2016},
Pages = {695-696},
Publisher = {IEEE},
Year = {2016},
Month = {October},
ISBN = {9781467388016},
url = {http://dx.doi.org/10.1109/URSIAP-RASC.2016.7601257},
Abstract = {Ground-penetrating radar (GPR), as one of the promising
non-destructive detection and imaging tools, has been
popularly applied in various fields. In this paper, we
present a milti-input and multi-output (MIMO) GPR system for
subsurface imaging of lunar regolith structure. This system
is equipped with twelve Vivaldi antennas, each of which can
be used as transmitter and receiver. Unlike a traditional
GPR system, this system works in a stationary mode, and
would not move along the survey line. We developed a
two-dimensional reverse time migration algorithm for
high-resolution subsurface imaging using this MIMO GPR
system. RTM algorithm mainly consists three steps, i.e. the
forward and backward modeling of the electromagnetic fields,
and the imaging condition. As a mature technology, the
finite-difference time-domain (FDTD) method simulates the
transient electromagnetic wave field. Those antennas in the
computation region are simplified as point sources at
corresponding position. In the underground area.
Cross-correlation of the forward and backward
electromagnetic fields in the computation domain is used as
the imaging condition. Fig. I shows the model for a
two-dimensional numerical experiment. Only ten antennas are
applied in the 2-D RTM algorithm since the other two
antennas are out of the imaging plane. The relative
dielectric permittivity and electric conductivity of the
lunar soil are respectively set to be 2.5 and 0.0 I mS/m.
Since no prior information about the subsurface structure
and the buried objects could be obtained, a half-space
initial model is employed for the 2D RTM. After the image
reconstruction by RTM, we can clearly identify the buried
object as well as the air/soil interface, as shown in Fig.
2. In the laboratory experiment, as shown in Fig. 3, a
marble slab of 60 cm x 60 cm is buried at the depth of 2 m
in a volcanic ash pit. The dielectric properties of the
volcanic ash are close to those of lunar soil. The relative
dielectric permittivity of the volcanic ash is about 2.5 and
the electric conductivity is negligibly small. The thickness
and relative dielectric permittivity of the marble slab are
3 cm and about 8, respectively. At the depth of 2.5 m, e.g.
the bottom of the ash pit, there is a metal plate. A
frequency domain filter is applied to the acquired
three-dimensional laboratory dataset to the two-dimensional
counterpart required for the 2D RTM. Fig. 4 depicts the RTM
result of the buried marble slab. We can identify the upper
and lower interfaces of the slabs, although they are only 3
cm in thickness. This means that the MIMO GPR system has a
depth resolution better than 3 cm in marble rock.
Considering the velocity difference in marble and lunar
soil, we can conclude that the MIMO GPR system has a depth
resolution of about 5 cm in lunar soil.},
Doi = {10.1109/URSIAP-RASC.2016.7601257},
Key = {fds323116}
}
@article{fds323117,
Author = {Liu, N and Cai, G and Liu, QH},
Title = {The efficient finite element method with impedance
transmission boundary condition for computing optical
waveguide modes},
Journal = {2016 Ursi Asia Pacific Radio Science Conference, Ursi Ap
Rasc 2016},
Pages = {1-2},
Publisher = {IEEE},
Year = {2016},
Month = {October},
ISBN = {9781467388016},
url = {http://dx.doi.org/10.1109/URSIAP-RASC.2016.7601259},
Abstract = {In this paper, we propose an efficient finite element method
with impedance transmission boundary condition (ITBC) to
significantly improve the numerical solutions of the optical
waveguide problems. It utilizes the curl-conforming linear
tangential and quadratic normal (LT/QN) edge elements to
expand the tangential component of the electric field, and
the second order nodal-based scalar basis functions to
expand the longitudinal component. Furthermore, to avoid the
very fine spatial discretization of thin lossy sheet, ITBC
has been proposed for the FEM formulations. The graphene
plasmonic waveguide verify that the FEM with ITBC technique
has high efficiency.},
Doi = {10.1109/URSIAP-RASC.2016.7601259},
Key = {fds323117}
}
@article{fds323086,
Author = {Shi, L and Liu, N and Zhou, J and Zhou, Y and Wang, J and Liu,
QH},
Title = {Spectral element method for band-structure calculations of
3D phononic crystals},
Journal = {Journal of Physics D: Applied Physics},
Volume = {49},
Number = {45},
Pages = {455102-455102},
Publisher = {IOP Publishing},
Year = {2016},
Month = {October},
url = {http://dx.doi.org/10.1088/0022-3727/49/45/455102},
Abstract = {The spectral element method (SEM) is a special kind of
high-order finite element method (FEM) which combines the
flexibility of a finite element method with the accuracy of
a spectral method. In contrast to the traditional FEM, the
SEM exhibits advantages in the high-order accuracy as the
error decreases exponentially with the increase of
interpolation degree by employing the Gauss-Lobatto-Legendre
(GLL) polynomials as basis functions. In this study, the
spectral element method is developed for the first time for
the determination of band structures of 3D
isotropic/anisotropic phononic crystals (PCs). Based on the
Bloch theorem, we present a novel, intuitive discretization
formulation for Navier equation in the SEM scheme for
periodic media. By virtue of using the orthogonal Legendre
polynomials, the generalized eigenvalue problem is converted
to a regular one in our SEM implementation to improve the
efficiency. Besides, according to the specific geometry
structure, 8-node and 27-node hexahedral elements as well as
an analytic mesh have been used to accurately capture curved
PC models in our SEM scheme. To verify its accuracy and
efficiency, this study analyses the phononic-crystal plates
with square and triangular lattice arrangements, and the 3D
cubic phononic crystals consisting of simple cubic (SC),
bulk central cubic (BCC) and faced central cubic (FCC)
lattices with isotropic or anisotropic scatters. All the
numerical results considered demonstrate that SEM is
superior to the conventional FEM and can be an efficient
alternative method for accurate determination of band
structures of 3D phononic crystals.},
Doi = {10.1088/0022-3727/49/45/455102},
Key = {fds323086}
}
@article{fds341213,
Author = {Wang, B and Zhao, Z and Yang, Y and Liu, S and Nie, Z and Liu,
QH},
Title = {Robust Compressed Sensing recovery for detecting
two-dimensional scatters},
Journal = {Call for Papers Iccem 2016: 2016 Ieee International
Conference on Computational Electromagnetics},
Pages = {89-91},
Year = {2016},
Month = {October},
ISBN = {9781467396783},
url = {http://dx.doi.org/10.1109/COMPEM.2016.7588658},
Abstract = {In this paper, a robust compressive sensing (CS) recovery
method for detecting and imaging two-dimensional scatters is
proposed. The proposed method reformulates the inverse
scatter problem into a Bounded-Constraint Quadratic Program
(BCQP) which can be solved efficiently by gradient
projection. Compared with the state-of-The art Bayesian
Compressed Sensing (BCS) inversion method, simulation
verified that the proposed method preforms more robust and
effective in low SNR, mutual effect and non-sparse
scenarios.},
Doi = {10.1109/COMPEM.2016.7588658},
Key = {fds341213}
}
@article{fds341110,
Author = {Huang, X and Liu, Y and You, P and Yang, J and Liu, QH},
Title = {Efficient phase-only linear array synthesis including mutual
coupling and platform effect},
Journal = {Call for Papers Iccem 2016: 2016 Ieee International
Conference on Computational Electromagnetics},
Pages = {328-329},
Year = {2016},
Month = {October},
ISBN = {9781467396783},
url = {http://dx.doi.org/10.1109/COMPEM.2016.7588670},
Abstract = {The least-square active element pattern expansion (LS-AEPE)
has been introduced for linear array synthesis including
mutual coupling and platform effect. A new method based on
combination of LS-AEPE and iterative Fourier transform (IFT)
is proposed to optimize the excitation phases for sidelobe
reduction and null control. Simulation results illustrate
the new method outperforms the GA-FFT method base on LS-AEPE
in terms of computational efficiency.},
Doi = {10.1109/COMPEM.2016.7588670},
Key = {fds341110}
}
@article{fds341111,
Author = {Yang, J and Liu, Y and Huang, X and Tan, X and Liu, QH},
Title = {Beam-scanning sparse array design with minimum spacing
constraint},
Journal = {Call for Papers Iccem 2016: 2016 Ieee International
Conference on Computational Electromagnetics},
Pages = {92-94},
Year = {2016},
Month = {October},
ISBN = {9781467396783},
url = {http://dx.doi.org/10.1109/COMPEM.2016.7588595},
Abstract = {In this paper, we propose a new method to design a
beam-scanning sparse array with minimum spacing constraint.
The proposed method consists of two optimization steps. In
the first step, an iterative reweighted L1-norm optimization
is used to obtain an initial sparse array without minimum
spacing constraint. In the second step, we carry on a series
of element combination and perturbations to meet the minimum
spacing constraint. An example is given to design a sparse
array which has the minimum spacing of 0.5 wavelength and
the beam scanning from-45° to 135°.},
Doi = {10.1109/COMPEM.2016.7588595},
Key = {fds341111}
}
@article{fds323092,
Author = {Liu, Y and Zhao, Z and Yang, Y and Wang, B and Zhu, X and Nie, Z and Liu,
QH},
Title = {A Frequency-Hopping Subspace-Based Optimization Method for
Reconstruction of 2-D Large Uniaxial Anisotropic Scatterers
with TE Illumination},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {54},
Number = {10},
Pages = {6091-6099},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {October},
url = {http://dx.doi.org/10.1109/TGRS.2016.2580759},
Abstract = {Due to the nonlinear property of large uniaxial anisotropic
scatterers, many iterative optimization methods have a high
risk of being trapped in local minima. In this paper, a
frequency-hopping subspace-based optimization method (SOM)
is proposed to reconstruct the relative permittivity
distribution of 2-D large uniaxial anisotropic scatterers
with transverse electrical (TE) illumination. This hybrid
method utilizes the results obtained at lower frequency to
provide good initial guesses for higher frequency
reconstruction, which reduces the occurrence of local minima
for the inversion at the higher frequency. For lower
frequency, it can only obtain coarse resolution image
although it is unable to show the details of the scatterers.
However, this coarse image provides a priori information for
the reconstruction at higher frequencies to get finer
resolution. Numerical examples demonstrate that the proposed
hybrid method can effectively rebuild large uniaxial
anisotropic scatterers (six wavelengths) with higher
stability compared with conventional SOM that uses only
single-frequency data.},
Doi = {10.1109/TGRS.2016.2580759},
Key = {fds323092}
}
@article{fds323093,
Author = {Ren, Y and Huang, WF and Liu, QH and Chen, YP and Zhang,
HS},
Title = {Accurate Fracture Scattering Simulation by Thin Dielectric
Sheet-Based Surface Integral Equation},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {13},
Number = {10},
Pages = {1448-1451},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {October},
url = {http://dx.doi.org/10.1109/LGRS.2016.2591079},
Abstract = {The thin dielectric sheet-based surface integral equation
(SIE) method is introduced to the accurate simulation of
fracture scattering, which is an important and challenging
topic in hydrocarbon exploration. In the proposed method,
the equivalent volume current is decomposed into the
equivalent surface current and the constant normal current.
With this decomposition, the D-field volume integral
equation degenerates into the SIE, which makes our proposed
method stable, accurate, and efficient at low frequency.
Numerical results have demonstrated its excellent
performance.},
Doi = {10.1109/LGRS.2016.2591079},
Key = {fds323093}
}
@article{fds323094,
Author = {Ren, Y and Huang, WF and Niu, J and Liu, QH},
Title = {Nearly Hypersingular Integrals by Double-Arctan
Transformation in Higher Order Geometry Modeling},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {10},
Pages = {4493-4498},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {October},
url = {http://dx.doi.org/10.1109/TAP.2016.2587746},
Abstract = {In order to directly utilize the dyadic Green's functions in
surface integral equations (SIEs), a novel double-arctan
transformation for nearly hypersingular integrals is
proposed in this communication. This new transformation is
flexible and applicable to nearly hypersingular integrals in
the forms of RR/R3, R/R3, and 1/R3 over the curved surfaces
by a fully numerical method. With the help of the sigmoidal
transformation to improve the stability of this new
singularly handling method, there results an efficient
solution for the third-order near-singularity problems in
SIEs. Moreover, the proposed method is also effective for
the lower orders of the nearly singular integral kernels.
With typical testing cases, the performance of this method
is fairly evaluated, and its validity and stability is well
demonstrated.},
Doi = {10.1109/TAP.2016.2587746},
Key = {fds323094}
}
@article{fds323095,
Author = {Li, F and Liu, QH and Klemer, DP},
Title = {Numerical Simulation of high electron mobility transistors
based on the spectral element Method},
Journal = {Applied Computational Electromagnetics Society
Journal},
Volume = {31},
Number = {10},
Pages = {1144-1150},
Year = {2016},
Month = {October},
Abstract = {The spectral element method (SEM) is implemented for the
numerical simulation of high electron mobility transistors
(HEMTs) through a selfconsistent solution of the
Schrödinger-Poisson equations. The electron conduction band
structure and electron density distribution are calculated
and plotted, and results compared to those based on methods
utilizing a finite-difference approach. Simulation accuracy
and efficiency are analyzed and compared with traditional
finite difference method (FDM). DC current-voltage (I-V)
characteristics for the HEMT structure are simulated, based
on a quasi-2D current model. The SEM approach offers
advantages in speed and efficiency over FDM, while yielding
results which conform well to reported experimental results.
These advantages are particularly important for compound
heterojunction devices with complex material profiles, for
which FDM methods may be inefficient and computationally
slow.},
Key = {fds323095}
}
@article{fds341214,
Author = {Zhu, CH and Yang, L and Liu, N and Liu, QH},
Title = {A new property of the effective permittivity in polymeric
medium with random distribution of spherical
nanoparticles},
Journal = {Epl (Europhysics Letters)},
Volume = {116},
Number = {1},
Year = {2016},
Month = {October},
url = {http://dx.doi.org/10.1209/0295-5075/116/17002},
Abstract = {In polymeric medium with random distribution of plasmonic
spherical nanoparticles, we find that the real and imaginary
parts of the effective permittivity form a circle. Though
the effective permittivity depends on the permittivity of
the host medium, the fill fraction of guest nanoparticles,
the resonance frequency of plasmonic spherical particles and
the frequency of incident wave, the center and the radius of
the circle are only decided by the permittivity of the host
medium and the fill fraction of guest nanoparticles.
Numerical computations for different kinds of polymeric
media and different fill fractions verify the
results.},
Doi = {10.1209/0295-5075/116/17002},
Key = {fds341214}
}
@article{fds341215,
Author = {Liu, H and Zhang, YX and Long, ZJ and Han, F and Liu,
QH},
Title = {Three-dimensional reverse-time migration applied to a MIMO
GPR system for subsurface imaging},
Journal = {Proceedings of 2016 16th International Conference of Ground
Penetrating Radar, Gpr 2016},
Year = {2016},
Month = {September},
ISBN = {9781509051816},
url = {http://dx.doi.org/10.1109/ICGPR.2016.7572682},
Abstract = {Compared with a conventional single-channel GPR system, a
GPR system with a multi-input and multioutput (MIMO) antenna
array is not only more efficient in 3D data acquisition, but
also allows the collection of a multi-offset dataset,
thereby providing additional information for more effective
subsurface imaging. We develop a three-dimensional (3-D)
reverse time migration (RTM) algorithm for processing MIMO
GPR data. The finite-difference time-domain method with a
convolutional perfect matching layer boundary is used to
simulate the propagation of electromagnetic waves in
subsurface dissipative media. The range and lateral
resolution of a MIMO GPR system, which works at a stationary
mode, is analyzed by numerical experiments. Furthermore,
results of laboratory experiments would be presented in the
extended abstract.},
Doi = {10.1109/ICGPR.2016.7572682},
Key = {fds341215}
}
@article{fds340833,
Author = {Long, ZJ and Zhang, YX and Liu, H and Wu, JW and Ouyang, WZ and Xia, YY and Liu, QH},
Title = {GPR inspection of asphalt pavement using an off-ground
antenna array},
Journal = {Proceedings of 2016 16th International Conference of Ground
Penetrating Radar, Gpr 2016},
Publisher = {IEEE},
Year = {2016},
Month = {September},
ISBN = {9781509051816},
url = {http://dx.doi.org/10.1109/ICGPR.2016.7572701},
Abstract = {We have published a ground-coupled GPR antenna array, which
consists of one transmitter and five receivers, for in situ
estimation of the thickness and dielectric permittivity of
an asphalt pavement layer [1]. In this paper, we optimize
the design of the antipodal Vivaldi antenna to pursue a
higher resolution through reducing the late-time ringing.
Furthermore, an off-ground antenna array is assembled, and
can effectively accelerate the acquisition of common-source
GPR datasets. The antenna phase center was calibrated to
estimate the velocity and thickness of both the air gap and
asphalt pavement layer, through velocity spectrum analysis.
Numerical experimental results show that the off-ground
antenna array is one ideal method for inspecting asphalt
pavements.},
Doi = {10.1109/ICGPR.2016.7572701},
Key = {fds340833}
}
@article{fds321708,
Author = {Li, JH and Liu, QH},
Title = {Fast frequency-domain forward and inverse methods for
acoustic scattering from inhomogeneous objects in layered
media},
Journal = {Journal of Computational Acoustics},
Volume = {24},
Number = {3},
Pages = {1650008-1650008},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1142/S0218396X16500089},
Abstract = {The fast scattering and inverse scattering algorithms for
acoustic wave propagation and scattering in a layered medium
with buried objects are an important research topic,
especially for large-scale geophysical applications and for
target detection. There have been increasing efforts in the
development of practical, accurate, and efficient means of
imaging subsurface target anomalies. In this work, the
acoustic scattering problem in layered media is formulated
as a volume integral equation and is solved by the
stabilized bi-conjugate gradient fast Fourier transform
(BCGS-FFT) method. By splitting the layered medium Green's
function interacting with the induced source into a
convolution and a correlation, the acoustic fields can be
calculated efficiently by the FFT algorithm. This allows
both the forward solution and inverse solution to be
computed with only O(Nlog N) computation time per iteration,
where N is the number of degrees of freedom. The inverse
scattering is solved using a simultaneous multiple frequency
contrast source inversion (CSI). The stable convergence of
this inversion process makes the multiple frequency
simultaneous CSI reconstruction practical for large acoustic
problems. Some representative examples are shown to
demonstrate the effectiveness of the forward and inverse
solvers for acoustic applications.},
Doi = {10.1142/S0218396X16500089},
Key = {fds321708}
}
@article{fds323097,
Author = {Wei, S and Zhou, J and Zhuang, M and Liu, QH},
Title = {A 3-D enlarged cell technique (ECT) for elastic wave
modelling of a curved free surface},
Journal = {Geophysical Journal International},
Volume = {206},
Number = {3},
Pages = {1921-1932},
Publisher = {Oxford University Press (OUP)},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1093/gji/ggw255},
Abstract = {The conventional finite-difference time-domain (FDTD) method
for elastic waves suffers from the staircasing error when
applied to model a curved free surface because of its
structured grid. In this work, an improved, stable and
accurate 3-D FDTD method for elastic wave modelling on a
curved free surface is developed based on the finite volume
method and enlarged cell technique (ECT). To achieve a
sufficiently accurate implementation, a finite volume scheme
is applied to the curved free surface to remove the
staircasing error; in the mean time, to achieve the same
stability as the FDTD method without reducing the time step
increment, the ECT is introduced to preserve the solution
stability by enlarging small irregular cells into adjacent
cells under the condition of conservation of force. This
method is verified by several 3-D numerical examples.
Results show that the method is stable at the Courant
stability limit for a regular FDTD grid, and has much higher
accuracy than the conventional FDTD method.},
Doi = {10.1093/gji/ggw255},
Key = {fds323097}
}
@article{fds323098,
Author = {Zhang, L and Wu, S and Xu, K and Yan, S and Zhu, J and Lin, T and Huo Liu,
Q},
Title = {Ultrathin plasmonic frequency selective surface with
subwavelength hole arrays},
Journal = {Microwave and Optical Technology Letters},
Volume = {58},
Number = {9},
Pages = {2171-2176},
Publisher = {WILEY},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1002/mop.30005},
Abstract = {Manipulation of optical transmission using plasmonic
nanostructures is a significant issue in applications
related to ultra-compact optoelectronic devices. In this
paper, we present a type of plasmonic frequency selective
surface constructed with an ultrathin gold film (∼20 nm)
with arrays of subwavelength holes. By means of modified
nanosphere lithography, we fabricate the nanostructured gold
films with scalable sizes and tunable transmission in the
visible and near-infrared range. Moreover, electromagnetic
simulations are performed and demonstrate good agreement
with experimental results and further reveal the evolution
of optical properties from the optically thick film to the
ultrathin film. The research achievements will provide
significant design guidance of ultrathin plasmonic frequency
selective surface for future nanophotonic devices. © 2016
Wiley Periodicals, Inc. Microwave Opt Technol Lett
58:2171–2176, 2016.},
Doi = {10.1002/mop.30005},
Key = {fds323098}
}
@article{fds323099,
Author = {Zhang, L and Zhang, S and Song, Z and Liu, Y and Ye, L and Liu,
QH},
Title = {Adaptive Decoupling Using Tunable Metamaterials},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {64},
Number = {9},
Pages = {2730-2739},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1109/TMTT.2016.2590385},
Abstract = {A novel method of decoupling two closely placed antennas is
proposed based on tunable metamaterials. The experimental
results show that this method has more than 110-dB isolation
ratio, frequency and bandwidth reconfigurable ability, and
environmental adaptivity. These features are realized by
placing multiple varactor-based tunable resonant structures
between two antennas within the near-field region and by
using artificial intelligent algorithm to optimize the
transmission coefficient between the antennas. A case of
suppressing mutual coupling between two orthogonally
polarized arrays is given to demonstrate the versatility of
this method.},
Doi = {10.1109/TMTT.2016.2590385},
Key = {fds323099}
}
@article{fds323100,
Author = {Liu, J and Kong, L and Yang, X and Liu, QH},
Title = {First-Order Multipath Ghosts' Characteristics and
Suppression in MIMO Through-Wall Imaging},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {13},
Number = {9},
Pages = {1315-1319},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1109/LGRS.2016.2583795},
Abstract = {In this letter, we derive the distribution characteristics
of first-order multipath ghosts in a nested
multiple-input-multiple-output (MIMO) through-wall radar and
evaluate the efficacy of the phase coherence factor (PCF) in
ghost suppression. Different from a synthetic aperture
radar, the first-order multipath echoes of a nested MIMO
through-wall radar generate several ghosts. For example, for
a nested MIMO array composed of a compact receiving subarray
and M spatially dispersed transmitters, there are M ghosts
at the same side of the wall as the array. The mth ghost is
supposed to occur near the intersection of the line,
connecting the target and the center of the receiving
subarray, and the ellipse whose foci are the positions of
the target and the mth transmitter. Under the assumption of
phase uniform distribution clutter, the PCF can suppress the
ghosts up to-20 lg(1-(M2-1)/M2) dB, which is about 17.46 dB
when M = 2.},
Doi = {10.1109/LGRS.2016.2583795},
Key = {fds323100}
}
@article{fds323101,
Author = {Ren, Q and Sun, Q and Tobon, L and Zhan, Q and Liu, QH},
Title = {EB Scheme-Based Hybrid SE-FE DGTD Method for Multiscale em
Simulations},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {9},
Pages = {4088-4091},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1109/TAP.2016.2578308},
Abstract = {This communication presents an EB scheme subdomainlevel
discontinuous Galerkin time domain (DGTD) method for
multiscale simulations. It is an extension of the previous
subdomain-level DGTD research by combining the degree of
freedom efficiency of spectral element time domain method
and the mesh flexibility of the finite element time domain
method. Thus, the multiscale problems can be solved
efficiently by separating the geometrically fine and coarse
parts and meshing them with hexahedrons and tetrahedrons,
respectively, via a nonconformal mesh. The implicit-explicit
Runge-Kutta method is applied to the EB scheme DGTD method
to obtain an efficient time integration approach.},
Doi = {10.1109/TAP.2016.2578308},
Key = {fds323101}
}
@article{fds321709,
Author = {Ai, J and Zhang, YH and Xu, KD and Li, DT and Liu, QH},
Title = {Design of a high-selectivity quad-band bandpass filter based
on λ/4 resonators with alternative J/K inverters},
Journal = {Aeu International Journal of Electronics and
Communications},
Volume = {70},
Number = {8},
Pages = {1028-1033},
Publisher = {Elsevier BV},
Year = {2016},
Month = {August},
url = {http://dx.doi.org/10.1016/j.aeue.2016.04.019},
Abstract = {Based on λ/4 resonators, the synthesis design method for a
miniaturized high-selectivity microstrip quad-band bandpass
filter (BPF) with alternative J/K inverters has been
presented. Two dual-band λ/4 stepped impedance resonators
(SIRs) are employed to generate the 1st and 4th passbands,
while the 2nd and 3rd passbands are achieved by utilizing
four coupled λ/4 uniform impedance resonators (UIRs).
Moreover, the alternative J/K inverters form is proposed to
create an additional cross coupling, resulting in one pair
of transmission zeros (TZs) at each side of all the four
passbands. To verify the validity of the proposed method, a
quad-band BPF centered at 1.9, 4.1, 4.6 and 6.1 GHz with
respectively fractional bandwidths of 13.7%, 5.1%, 5.9% and
7.6% has been designed and fabricated, whose measured
results show consistent match with the simulated
ones.},
Doi = {10.1016/j.aeue.2016.04.019},
Key = {fds321709}
}
@article{fds323102,
Author = {Zhu, J and Bai, Y and Zhang, L and Song, Z and Liu, H and Zhou, J and Lin, T and Liu, QH},
Title = {Large-Scale Uniform Silver Nanocave Array for Visible Light
Refractive Index Sensing Using Soft UV Nanoimprint},
Journal = {Ieee Photonics Journal},
Volume = {8},
Number = {4},
Pages = {1-7},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {August},
url = {http://dx.doi.org/10.1109/JPHOT.2016.2585111},
Abstract = {In this paper, a wafer-scale uniform silver nanocave array
is fabricated by soft ultraviolet nanoimprint lithography.
We investigate its plasmonic effects using far-field and
near-field experimental approaches and illuminate the
physics inside by theoretical analysis and computational
simulation. The array shows robust multispectral features
for various surrounding media and possesses the sensitivity
up to 514.7 nm/RIU in the visible range, which is promising
for the mass production of high-performance plasmonic
refractive index sensors.},
Doi = {10.1109/JPHOT.2016.2585111},
Key = {fds323102}
}
@article{fds323103,
Author = {Ren, Y and Liu, QH and Chen, YP},
Title = {A Hybrid FEM/MoM Method for 3-D Electromagnetic Scattering
in Layered Medium},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {8},
Pages = {3487-3495},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {August},
url = {http://dx.doi.org/10.1109/TAP.2016.2575979},
Abstract = {Accurate and efficient prediction of electromagnetic
scattering from inhomogeneous objects in layered medium is
one of the most challenging issues in engineering
applications. This paper presents the first 3-D higher order
hybrid finite-element method (FEM) and method of moments
(MoM) for the accurate modeling of inhomogeneous dielectric
objects in multilayered medium. The main challenges of this
paper include: 1) the integration of these algorithms for
layered medium and 2) the higher order computational
approach involved in layered medium for high efficiency. In
the proposed method, the MoM with the layered medium dyadic
Green's function is used as the exact radiation boundary
condition in an inhomogeneous background, and the FEM is
applied to model the inhomogeneous objects. Furthermore, the
higher order maximally orthogonal basis functions with
curl-conforming and divergence-conforming properties are
used in the FEM and MoM, respectively to improve the
modeling capability of this algorithm. For 3-D inhomogeneous
objects scattering in multilayered medium, this new method
requires a much more tightly truncated simulation domain
than the traditional FEM, and provides much higher
flexibility than the pure surface integral equation method.
Finally, some numerical results are provided to validate the
accuracy, efficiency, and flexibility of this
method.},
Doi = {10.1109/TAP.2016.2575979},
Key = {fds323103}
}
@article{fds341112,
Author = {You, P and Liu, Y and Huang, X and Zhu, C and Liu, Q},
Title = {Modified GA-FFT for synthesizing shaped pattern of unequally
spaced array in presence of mutual coupling},
Journal = {Dianzi Yu Xinxi Xuebao/Journal of Electronics and
Information Technology},
Volume = {38},
Number = {8},
Pages = {2107-2112},
Year = {2016},
Month = {August},
url = {http://dx.doi.org/10.11999/JEIT151189},
Abstract = {A new Virtual Least-Square Active Element Pattern Expansion
(VLS-AEPE) method is presented in this paper, which
considers each active element pattern of an unequally spaced
array as the one radiated by some of equally spaced elements
of a virtual array. Using the help of this method, the
pattern of an unequally spaced array including mutual
coupling can be efficiently calculated by FFT. In addition,
this method is combined with the Genetic Algorithm (GA) to
deal with the shaped pattern synthesis problem for unequally
spaced linear arrays. Two synthesis experiments including
the synthesis of flat-top pattern for an unequally spaced
dipole array and the synthesis of cosec-squared pattern for
an unequally spaced microstrip array are conducted to verify
the effectiveness and advantages of the proposed
algorithm.},
Doi = {10.11999/JEIT151189},
Key = {fds341112}
}
@article{fds341195,
Author = {Zhu, C and Zhao, Z and Zhu, X and Nie, Z and Liu, QH},
Title = {Cloud removal for optical images using SAR structure
data},
Journal = {International Conference on Signal Processing Proceedings,
Icsp},
Pages = {1872-1875},
Year = {2016},
Month = {July},
ISBN = {9781509013449},
url = {http://dx.doi.org/10.1109/ICSP.2016.7878153},
Abstract = {Cloud cover impacts the quality of optical remote sensing
images. Generally, temporal methods and inpainting methods
are used to remove the clouds. The temporal methods
reconstruct cloudy areas via a series of multi-temporal
images, thus suffer from the assumption that the landscape
does not change over a period of time. The inpainting
methods fill the areas via image patches from the image
itself. Lacking prior information of the cloudy areas, these
methods are limited in reconstructing accuracy, especially
when clouds lie on the boundaries of two types of
landscapes. We propose a new method based on the inpanting
method which take the SAR (Synthetic Aperture Radar) images
as a prior structure information of contaminated. Using
information from two kinds of images acquired at the same
time, the proposed method also avoids inaccuracy caused by
land changes in temporal methods. This idea has been
demonstrated by experiments carried out on Theme Mapper data
and Sentinel-1A data. In terms of RMSE (Root Mean Square
Error), the proposed method is evaluated and compared with
several other cloud removal algorithm.},
Doi = {10.1109/ICSP.2016.7878153},
Key = {fds341195}
}
@article{fds341074,
Author = {Liu, Y and Zhao, Z and Zhu, X and Nie, Z and Liu, QH},
Title = {Investigation of the regularization parameter of
subspace-based optimization method for reconstruction of
uniaxial anisotropic objects},
Journal = {International Conference on Signal Processing Proceedings,
Icsp},
Pages = {1882-1885},
Year = {2016},
Month = {July},
ISBN = {9781509013449},
url = {http://dx.doi.org/10.1109/ICSP.2016.7878155},
Abstract = {This paper investigates influence of the regularization
parameter L on the performance of subspace-based
optimization method in reconstructing uniaxial anisotropic
objects. Some criteria are obtained to determine the
regularization parameter L. If L is too small, the cost
function may not converge well. If L is too large, the noise
will be amplified and deteriorate the inverse process. It is
found that the regularization parameter of SOM for
reconstruction of uniaxial anisotropic objects behaves
similarly as that in the isotropic case.},
Doi = {10.1109/ICSP.2016.7878155},
Key = {fds341074}
}
@article{fds321710,
Author = {Liao, Y and Wang, WQ and Liu, QH},
Title = {Two-Dimensional Spectrum for Circular Trace Scanning SAR
Based on an Implicit Function},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {13},
Number = {7},
Pages = {887-891},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {July},
url = {http://dx.doi.org/10.1109/LGRS.2016.2544799},
Abstract = {For circular trace scanning synthetic aperture radar
(CTSSAR), the conventional approximated quadratic range
equation assumption does not hold due to the impact of the
curved flight path. Thus, existing SAR methods cannot focus
the target accurately and efficiently in CTSSAR. To address
this problem, the stationary phase can be regarded as an
implicit function of the Doppler frequency. Therefore, the
2-D spectrum can be consequently achieved by employing the
principle of stationary phase. In this letter, an imaging
algorithm based on the derived spectrum is developed for
CTSSAR. Promising results from simulation demonstrate the
validity and effectiveness of the approach.},
Doi = {10.1109/LGRS.2016.2544799},
Key = {fds321710}
}
@article{fds323105,
Author = {Chen, Y and Yao, J and Song, Z and Ye, L and Cai, G and Liu,
QH},
Title = {Independent tuning of double plasmonic waves in a
free-standing graphene-spacer-grating-spacer-graphene hybrid
slab.},
Journal = {Optics Express},
Volume = {24},
Number = {15},
Pages = {16961-16972},
Year = {2016},
Month = {July},
url = {http://dx.doi.org/10.1364/oe.24.016961},
Abstract = {The independent excitation and tuning of double plasmonic
waves are realized in a free-standing graphene-spacer-grating-spacer-graphene
(GSGSG) hybrid slab, which consists of two graphene field
effect transistors placed back-to-back to each other.
Resulted from the high transparency and the tight
confinement of surface plasmonic mode for the graphene,
double plasmonic waves can be independently excited by
guided-mode resonances (GMRs). Theoretical and numerical
investigations are performed in the mid-infrared band.
Furthermore, the tuning of individual GMR resonant
wavelengths with respect to the system parameters is
studied. The results provide opportunities to engineer the
proposed hybrid slab for wavelength selective and
multiplexing applications.},
Doi = {10.1364/oe.24.016961},
Key = {fds323105}
}
@article{fds321711,
Author = {Liu, J and Kong, L and Yang, X and Liu, QH},
Title = {Refraction Angle Approximation Algorithm for Wall
Compensation in TWRI},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {13},
Number = {7},
Pages = {943-946},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {July},
url = {http://dx.doi.org/10.1109/LGRS.2016.2555291},
Abstract = {Wall penetration of the electromagnetic wave causes target
image defocused and displaced from its true position in
through-wall radar imaging. To solve this problem, this
letter proposes an approximate wall compensation algorithm,
named the refraction angle approximation algorithm, which
assumes that the actual refraction angle is approximately
equal to the one whose incidence angle is the azimuth angle
of the target. The assumption is reasonable since the
refraction angle is less sensitive to the incidence angle
and limited in a small range based on the Snell's law, and
the cosine function has a small derivative at a small angle.
Theoretical derivation indicates that the time delay
estimation error can be ignored if the target is not so
close to the wall surface around the radar. Numerical
simulation verifies the efficacy of the algorithm.},
Doi = {10.1109/LGRS.2016.2555291},
Key = {fds321711}
}
@article{fds323104,
Author = {Liu, J and Chen, Q and Li, J and Xiong, Q and Yue, G and Zhang, X and Yang, S and Liu, QH},
Title = {Facile synthesis of cuprous oxide nanoparticles by plasma
electrochemistry},
Journal = {Journal of Physics D: Applied Physics},
Volume = {49},
Number = {27},
Pages = {275201-275201},
Publisher = {IOP Publishing},
Year = {2016},
Month = {June},
url = {http://dx.doi.org/10.1088/0022-3727/49/27/275201},
Abstract = {We report on a simple plasma electrochemistry method for
synthesizing cuprous oxide (Cu2O) nanoparticles in the
presence of glucose. In this system, Ar plasma in contact
with a NaCl solution was used as one electrode, and a Cu
plate was immersed in the solution as the counter electrode.
The plasma-solution interaction produced many reducing and
oxidizing species which can react with the Cu ions released
from the Cu electrode. Cu2O nanoparticles, with an average
diameter of 22 6 nm, were formed under the competition of
reducing and oxidizing reactions in the solution. The
results show that the glucose added in the electrolyte
strongly influences the properties of the products.
Corresponding to high, medium, and low concentrations of
glucose, the products were nanoparticles from amorphous
Cu2O, polycrystalline Cu2O, and a mixture of polycrystalline
Cu2O and Cu2Cl(OH)3, respectively.},
Doi = {10.1088/0022-3727/49/27/275201},
Key = {fds323104}
}
@article{fds323114,
Author = {Li, J and Zhang, A and Liu, J and Liu, QH},
Title = {Cavity-backed wideband magneto-electric antenna for
through-The-wall imaging radar applications},
Journal = {2016 Ieee Radar Conference, Radarconf 2016},
Pages = {1371-1373},
Publisher = {IEEE},
Year = {2016},
Month = {June},
ISBN = {9781509008636},
url = {http://dx.doi.org/10.1109/RADAR.2016.7485327},
Abstract = {A wideband magneto-electric antenna is proposed for
through-The-wall imaging radar (TWIR) applications in the
frequency range 1.5-2.5 GHz. A rectangular cavity is
introduced to improve the total gain and the front-To-back
ratio (FBR) of the antenna. The through-The-wall imaging
(TTWI) performance of the proposed antenna aimed to detect
stationary targets has been investigated and compared with a
conventional Vivaldi antenna. The results obtained by
numerical simulations and processed by the back projection
(BP) algorithm show that, compared with the Vivaldi antenna,
the proposed antenna can not only detect the desired target,
but also eliminate the effect of the undesired back objects,
making it a promising candidate for TWIRs.},
Doi = {10.1109/RADAR.2016.7485327},
Key = {fds323114}
}
@article{fds323115,
Author = {Yang, H and Li, N and Li, T and He, Z and Liu, QH},
Title = {An improved reverse time migration for subsurface imaging in
layered media},
Journal = {2016 Ieee Radar Conference, Radarconf 2016},
Pages = {1119-1124},
Publisher = {IEEE},
Year = {2016},
Month = {June},
ISBN = {9781509008636},
url = {http://dx.doi.org/10.1109/RADAR.2016.7485279},
Abstract = {An improved reverse time migration (RTM) method is proposed
for borehole radar imaging in the subsurface scenarios with
layered media. The time gating function is designed and
applied to the incident wave field and scattering wave field
for each imaging point, which strengthens the correlation
between the wave fields in time domain. A normalized
zero-offset cross-correlation with gated samples is
conducted and used to weight the result of RTM. The improved
approach is compared with the conventional RTM, back
projection method, and Stolt migration algorithm with
synthetic data. The results demonstrate the developed
approach is superior to the conventional methods in locating
targets and robust in complex subsurface
environments.},
Doi = {10.1109/RADAR.2016.7485279},
Key = {fds323115}
}
@article{fds321712,
Author = {Xie, J and Guo, Z and Liu, H and Liu, QH},
Title = {Reverse time migration using the pseudospectral time-domain
algorithm},
Journal = {Journal of Computational Acoustics},
Volume = {24},
Number = {2},
Pages = {1650005-1650005},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {2016},
Month = {June},
url = {http://dx.doi.org/10.1142/S0218396X16500053},
Abstract = {We propose a pre-stack reverse time migration (RTM) seismic
imaging method using the pseudospectral time-domain (PSTD)
algorithm. Traditional pseudospectral method uses the fast
Fourier transform (FFT) algorithm to calculate the spatial
derivatives, but is limited by the wraparound effect due to
the periodicity assumed in the FFT. The PSTD algorithm
combines the pseudospectral method with a perfectly matched
layer (PML) for acoustic waves. PML is a highly effective
absorbing boundary condition that can eliminate the
wraparound effect. It enables a wide application of the
pseudospectral method to complex models. RTM based on the
PSTD algorithm has advantages in the computational
efficiency compared to traditional methods such as the
second-order and high order finite difference time-domain
(FDTD) methods. In this work, we implement the PSTD
algorithm for acoustic wave equation based RTM. By applying
the PSTD-RTM method to various seismic models and comparing
it with RTM based on the eighth-order FDTD method, we find
that PSTD-RTM method has better performance and saves more
than 50% memory. The method is suitable for parallel
computation, and has been accelerated by general purpose
graphics processing unit.},
Doi = {10.1142/S0218396X16500053},
Key = {fds321712}
}
@article{fds321714,
Author = {Xu, H and Xu, K and Liu, Y and Liu, QH},
Title = {Compact triple-mode bandpass filter using short- and
open-stub loaded spiral resonator},
Journal = {2016 Ieee/Aces International Conference on Wireless
Information Technology, Icwits 2016 and System and Applied
Computational Electromagnetics, Aces 2016
Proceedings},
Publisher = {IEEE},
Year = {2016},
Month = {May},
ISBN = {9781509012596},
url = {http://dx.doi.org/10.1109/ROPACES.2016.7465476},
Abstract = {A novel high-selectivity triple-mode microstrip bandpass
filter (BPF) using short- and open-stub loaded spiral
resonator is presented. Because of the spiral structure, the
size of designed BPF is reduced greatly. Then the odd- and
even-mode method is used to analyze resonant frequencies of
the resonator. Based on the analysis, a prototype of the
proposed BPF with good selectivity is designed whose center
frequency is at 4.3 GHz. Finally, the measured results are
shown, which are in good agreement with simulations.},
Doi = {10.1109/ROPACES.2016.7465476},
Key = {fds321714}
}
@article{fds321713,
Author = {Li, M and Xu, K and Bai, Y and Liu, Y and Liu, QH},
Title = {Planar microstrip tri-mode bandpass filter using
center-stub-loaded spiral resonator},
Journal = {2016 Ieee/Aces International Conference on Wireless
Information Technology, Icwits 2016 and System and Applied
Computational Electromagnetics, Aces 2016
Proceedings},
Publisher = {IEEE},
Year = {2016},
Month = {May},
ISBN = {9781509012596},
url = {http://dx.doi.org/10.1109/ROPACES.2016.7465477},
Abstract = {A new tri-mode banpass filter (BPF) using a half-wavelength
spiral resonator center-loaded with two T-shaped open stubs
has been presented. Analyzed by the odd- and even-mode
method, an odd mode and two even modes of the proposed
tri-mode resonator could be flexibly controlled by tuning
the electrical length of the spiral resonators and T-shaped
stubs. For demonstration purpose, a tri-mode filter example
with passband centered at 1.8 GHz has been
implemented.},
Doi = {10.1109/ROPACES.2016.7465477},
Key = {fds321713}
}
@article{fds321715,
Author = {Liu, J and Jia, Y and Kong, L and Yang, X and Liu, QH},
Title = {MIMO through-wall radar 3-D imaging of a human body in
different postures},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {30},
Number = {7},
Pages = {849-859},
Publisher = {Informa UK Limited},
Year = {2016},
Month = {May},
url = {http://dx.doi.org/10.1080/09205071.2016.1159996},
Abstract = {This paper focuses on three-dimensional (3-D) imaging for
the human body with different postures to enhance the
situation awareness ability of through-wall radar. First, we
design a two-dimensional MIMO array where the receiving
antennas are uniformly and sparsely arranged in horizontal
and vertical directions and four time-division multiplexing
transmitting elements are placed at the four array corners.
As a result, the equivalent aperture is closed to four times
the size of the physical array. Second, an identical
time-delay wall compensation algorithm attached to
back-projection algorithm is presented to easily and
approximately correct the image distortion caused by wall
penetration, which employs an identical time-delay offset in
the whole 3-D pixel-to-pixel imaging process to partially
balance out multiple different focusing time-delay errors
corresponding to multiple transmit-receive channels in each
pixel. Finally, we develop a human body model with three
typical postures in the FDTD simulation. Based on the MIMO
array and the time-delay compensation algorithm, the
simulated images created via the back-projection algorithm
clearly provide the identifiable posture
characteristics.},
Doi = {10.1080/09205071.2016.1159996},
Key = {fds321715}
}
@article{fds323106,
Author = {Feng, X and Zhang, Y and Zhu, G and Fan, Y and Joines, WT and Huo Liu,
Q},
Title = {Design of LPF using suspended substrate microstrip lines as
high-Z sections for stopband extension},
Journal = {Microwave and Optical Technology Letters},
Volume = {58},
Number = {5},
Pages = {1204-1207},
Publisher = {WILEY},
Year = {2016},
Month = {May},
url = {http://dx.doi.org/10.1002/mop.29767},
Abstract = {This article introduces the use of suspended substrate
microstrip lines (SSMLs) as high-Z sections in the design of
lowpass filters (LPFs) to extend the stopband. The SSMLs are
formed by etching slots on the backside of microstrip lines
and placing the substrate on an aluminum base with grooves
that cover these slots. The higher characteristic impedance
property of SSMLs brings about not only shorter length for
high-Z lines but also a larger high-to-low impedance ratio,
thus deepening the stopband suppression and shifting the
spurious passband away. As a demonstration, a wide stopband
LPF combining this structure with hammer-shaped stubs is
designed, fabricated, and measured. The 20 dB stopband is
obtained from 1.45 to 11.77 GHz. Compared with reported
LPFs, this shows the widest fractional bandwidth (FBW) of
156% without sacrificing other performances.},
Doi = {10.1002/mop.29767},
Key = {fds323106}
}
@article{fds321716,
Author = {Yang, H and Li, T and Li, N and He, Z and Liu, QH},
Title = {Time-Gating-Based Time Reversal Imaging for Impulse Borehole
Radar in Layered Media},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {54},
Number = {5},
Pages = {2695-2705},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {May},
url = {http://dx.doi.org/10.1109/TGRS.2015.2504725},
Abstract = {In this paper, the formulation of reverse time migration
(RTM) is improved for impulse borehole radar imaging in the
subsurface scenarios with layered media. By fully adopting
the prior information of surrounding media, the time gating
function is designed and applied to the incident wave field
and scattering wave field for each imaging point, which
strengthens the correlation between the wave fields in the
time domain. The clutters partly caused by the multiple
reflections between different media layers are suppressed
due to the gating function. A normalized zero-offset cross
correlation with gated samples is conducted and used to
weight the result of RTM. The improved approach is compared
with the conventional RTM, the back-projection method, and
the Stolt migration algorithm with synthetic data and is
then validated by a single-borehole radar experiment in a
layered media scenario. The results demonstrate that the
developed approach is superior to the conventional methods
in locating targets and robust in complex subsurface
environments.},
Doi = {10.1109/TGRS.2015.2504725},
Key = {fds321716}
}
@article{fds321717,
Author = {Ai, J and Zhang, Y and Xu, KD and Guo, Y and Joines, WT and Liu,
QH},
Title = {Compact sext-band bandpass filter based on single multimode
resonator with high band-to-band isolations},
Journal = {Electronics Letters},
Volume = {52},
Number = {9},
Pages = {729-731},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1049/el.2016.0227},
Abstract = {On the basis of a single multimode resonator (MMR), a
miniaturised microstrip sext-band bandpass filter (BPF) with
high band-to-band isolations has been presented. The
proposed MMR is an stepped impedance resonator (SIR) with
one short-circuited stub loaded in the middle and two
identical open-circuited stubs located at two sides.
Transmission poles (TPs) and transmission zeros (TZs) can be
excited when the electrical lengths of two open stubs
increase. The TZs introduced by open stubs separate the TPs
into multiple groups; therefore, the design of a sext-band
BPF becomes available. Moreover, two input/output tapped
branches and radical stub-loaded short-circuited lines are
treated as perturbation structures in order to increase
design freedoms for improving filter performance. Good
agreement between simulated and measured results validates
the design method.},
Doi = {10.1049/el.2016.0227},
Key = {fds321717}
}
@article{fds323107,
Author = {Zheng, J and Liu, H and Liao, G and Su, T and Liu, Z and Liu,
QH},
Title = {ISAR imaging of targets with complex motions based on a
noise-resistant parameter estimation algorithm without
nonuniform axis},
Journal = {Ieee Sensors Journal},
Volume = {16},
Number = {8},
Pages = {2509-2518},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1109/JSEN.2016.2516040},
Abstract = {In inverse synthetic aperture radar (ISAR) imaging of
targets with complex motions, such as highly maneuvering
airplanes and ships fluctuating with oceanic waves, azimuth
echoes of a range cell have to be modeled as multicomponent
cubic phase signals (CPSs) after the range alignment and the
phase adjustment. Due to the time-varying Doppler
frequencies of scatterers, ISAR image obtained with the
standard range-Doppler algorithm is blurred, and the
range-instantaneous-Doppler (RID) technique is required to
improve the image quality. In this paper, by employing a
novel parametric autocorrelation function and the
generalized scaled Fourier transform, an effective parameter
estimation algorithm is proposed for multicomponent CPSs and
applied to reconstruct the RID image for targets with
complex motions. Analyses of the implementation, the
cross-term, the anti-noise performance, and the
computational cost demonstrate that, compared with other
three representative estimation algorithms, the proposed
algorithm can eliminate the brute-force searching procedure
and acquire a higher anti-noise performance without the
nonuniform axis. Through simulations and analyses for
synthetic models and the real radar data, we verify the
effectiveness of the proposed estimation algorithm and the
corresponding ISAR imaging algorithm.},
Doi = {10.1109/JSEN.2016.2516040},
Key = {fds323107}
}
@article{fds321718,
Author = {Yu, M and Ye, L and Chen, Y and Zhang, L and Liu, H and Liu,
QH},
Title = {Circular patch microstrip antenna with reconfigurable
polarization capability},
Journal = {2015 Ieee International Conference on Communication Problem
Solving, Iccp 2015},
Pages = {314-315},
Publisher = {IEEE},
Year = {2016},
Month = {April},
ISBN = {9781467365437},
url = {http://dx.doi.org/10.1109/ICCPS.2015.7454160},
Abstract = {A reconfigurable microstrip antenna with polarization
diversities is presented in this paper. The reconfigurable
antenna's structure consists of a circular patch embedded by
two slots with four PIN diodes mounted on them. The
reconfigurable polarization property of the proposed antenna
is achieved by switching ON/OFF states of these diodes. Both
HFSS simulation and experimental testing are carried out to
characterize the antenna's performance. The investigation
results show that this antenna has good reconfigurable
characteristic between circular polarization (CP) and linear
polarization (LP), which may have many potential
applications in modern wireless communication
systems.},
Doi = {10.1109/ICCPS.2015.7454160},
Key = {fds321718}
}
@article{fds321719,
Author = {Zhang, L and Song, Z and Ye, L and Liu, Y and Liu, QH},
Title = {Experimental investigation on high efficiency decoupling
using tunable metamaterials},
Journal = {2015 International Symposium on Antennas and Propagation,
Isap 2015},
Year = {2016},
Month = {April},
ISBN = {9784885523038},
Abstract = {More than 110 dB isolation is experimentally realized in a
narrow band in this work. Multiple varactors based tunable
metamaterials were placed between two co-polarized monopole
antennas. The metamaterials are controlled using an genetic
algorithm (GA) based optimization program. The optimization
goal is to minimize the transmission coefficient of a. After
3000 generations of evolution, more than 110 dB isolation
ratio is achieved. This method is verified by two
experiments with different metamaterial structures.},
Key = {fds321719}
}
@article{fds323108,
Author = {Zhang, Y and Feng, N and Zheng, H and Liu, H and Zhu, J and Liu,
QH},
Title = {A Corner-Free Truncation Strategy in Three-Dimensional FDTD
Computation},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {58},
Number = {2},
Pages = {512-522},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1109/TEMC.2015.2510297},
Abstract = {The corner-free truncation (CFT) strategy is proposed to
improve the efficiency of numerical simulation in
computational electrodynamics. The spherical boundary,
namely the CFT strategy, is built up in the Cartesian
coordinate system, which has been implemented via making use
of the impedance-matched layer. The proposed CFT strategy is
used for terminating computational domain of the
conventional finite-difference time-domain (FDTD) to absorb
the outward electromagnetic waves. Moreover, based on the
proposed boundary, the computation becomes simpler. The
original FDTD computational domain is reduced to be nearly a
half, and the computational resource is saved significantly,
both of which are due to the fact that no curvilinear model
is applied in truncating the boundary. The numerical
simulations of target scattering problems have been achieved
to validate the proposed algorithm.},
Doi = {10.1109/TEMC.2015.2510297},
Key = {fds323108}
}
@article{fds321720,
Author = {Zhou, Y and Shi, L and Liu, N and Zhu, C and Liu, H and Liu,
QH},
Title = {Spectral Element Method and Domain Decomposition for
Low-Frequency Subsurface em Simulation},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {13},
Number = {4},
Pages = {550-554},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1109/LGRS.2016.2524558},
Abstract = {Low-frequency subsurface electromagnetic measurements are
important tools for characterizing natural resources and
environmental wastes. Rapid simulations of low-frequency
subsurface electromagnetic measurements are still a
challenge because of the large computational domain and
low-frequency breakdown phenomenon. We develop an effective
method to simulate these low-frequency subsurface
electromagnetic measurements by using the spectral element
method together with a domain decomposition method (DDM). A
specific mesh has been designed based on the traveling wave
nature in the air and the diffusion field nature in the
underground space to greatly reduce the number of unknowns.
The frequency-domain version of the Riemann solver (upwind
flux) is used as an effective transmission condition to
simulate the interactions between neighboring subdomains in
DDM. Several numerical examples demonstrate the efficiency
of the proposed approach in low-frequency subsurface
electromagnetics simulations.},
Doi = {10.1109/LGRS.2016.2524558},
Key = {fds321720}
}
@article{fds321721,
Author = {Zhang, X and Zhou, R and Chen, M and Li, J and Sun, Y and Chen, Q and Yang, S and Liu, QH},
Title = {Treatment of ribonucleoside solution with
atmospheric-pressure plasma},
Journal = {Plasma Processes and Polymers},
Volume = {13},
Number = {4},
Pages = {429-437},
Publisher = {WILEY},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1002/ppap.201500088},
Abstract = {A self-made microplasma jet array device is used to treat
deoxyadenosine (dA) and adenosine (Ado) solutions to avoid
the effect of air on genetic materials. Results show that
Ado is easily converted into dA through deoxidation
reaction. In addition, dA solution is treated with different
microplasma arrays (i.e., atmospheric-pressure Ar, N2, air,
and O2) for comparative analysis. The dA molecule is
relatively stable within the Ar plasma for 3 min treatment
time. This molecule can be modified into different
structures with N2, air, and O2 microplasma arrays. The
results obtained in this study provide references for the
application of plasma in biology and the effect of
oxygen-containing free radicals in biological plasma. As an
immediate and latest area of research focus, atmospheric
microplasma has wide applications in the biomedical field.
However, effects of plasma on ribonucleoside in DNA are less
studied and reported. A self-made microplasma jet array
device is used to treat basic blocks of DNA, and online
ion-pair reversed-phase liquid chromatography (IP-RPLC) with
electrospray tandem mass spectrometry (ESI-MS) is used to
detect the reaction process. Results show oxidative damage
to DNA is a complex process, influenced by charge transport
and reactions that are controlled by a combination of
enthalpic, entropic, steric, and compositional
factors.},
Doi = {10.1002/ppap.201500088},
Key = {fds321721}
}
@article{fds321722,
Author = {Ellis, MS and Zhao, Z and Wu, J and Ding, X and Nie, Z and Liu,
QH},
Title = {A Novel Simple and Compact Microstrip-Fed Circularly
Polarized Wide Slot Antenna with Wide Axial Ratio Bandwidth
for C-Band Applications},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {4},
Pages = {1552-1555},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1109/TAP.2016.2526076},
Abstract = {This communication presents a design of a new compact
circularly polarized (CP) slot antenna fed by a microstrip
feedline. The 3-dB axial ratio band can be achieved by
simply protruding a horizontal stub from the ground plane
toward the center of the wide slot (WS) and then feeding the
WS with a microstrip feedline positioned to the side of the
WS, underneath the protruded stub. The feedline and metallic
stub are perpendicular to each other, and they resemble a T
shape when viewed from the top. The proposed antenna is
fabricated with an area of 25 × 25 mm2. Measurement results
show that the antenna attains an S11 ≤ -10 dB impedance
matching bandwidth of 90.2%, from 3.5 to 9.25 GHz, and a
broadband 3 dB-AR bandwidth of 40%, ranging from 4.6 to 6.9
GHz. A peak gain of 0.8-4.5 dBi is achieved within the AR
band. The proposed antenna is suitable for circular
polarization applications in C band.},
Doi = {10.1109/TAP.2016.2526076},
Key = {fds321722}
}
@article{fds315033,
Author = {Niu, J and Luo, M and Liu, QH},
Title = {Enhancement of graphene's third-harmonic generation with
localized surface plasmon resonance under
optical/electro-optic Kerr effects},
Journal = {Journal of the Optical Society of America
B},
Volume = {33},
Number = {4},
Pages = {615-621},
Publisher = {The Optical Society},
Year = {2016},
Month = {April},
ISSN = {0740-3224},
url = {http://dx.doi.org/10.1364/JOSAB.33.000615},
Abstract = {Although graphene's particularly strong third-order
susceptibility has drawn intensive attention in theoretical
and experimental studies, its low bulk nonlinear response
heavily emphasizes the nanostructure's design for a
sufficient magnitude of third-harmonic generation (THG).
Meanwhile, currently few tools are available for accurate
theoretical analyses of graphene's nonlinear performance
within a relatively complex structure, which renders the
design of graphene-based nonlinear optoelectronic devices
even more challenging. In this work, a high-accuracy
self-consistent numerical solver based on the
boundary-integral spectral element method is first proposed
for the THG problem. Starting from the coupled vector wave
equations, the proposed solver solves for the fundamental
frequency field and third-harmonic field together
iteratively, and it covers the optical/electro-optic Kerr
effects ignored by most previous THG studies. After
validating the proposed method with the comparison between
numerical results and experimental data, we extend our study
to the THG enhancement strategy with ultrastrong localized
surface plasmon resonances (LSPRs) and Kerr effects. For
both optical and electro-optic Kerr effects, the systematic
simulation is performed for graphene's THG within the
incident spectra of 400-1000 nm. Compared with the THG of
floating single-atom-layer graphene, numerical results show
that under specific LSPR engineering, graphene's THG
backward emission is enhanced by 4.4 × 105 times.
Simultaneously applying the electro-optic Kerr process can
further boost the THG emission. However, its contribution is
only secondary compared with LSPR. This study is also
extended to bilayer and trilayer graphene models under
strong LSPR.},
Doi = {10.1364/JOSAB.33.000615},
Key = {fds315033}
}
@article{fds322883,
Author = {Kong, L and Li, N and Cui, G and Yang, H and Liu, QH},
Title = {Adaptive Bayesian detection for multipleinput
multiple-output radar in compound- Gaussian clutter with
random texture},
Journal = {Iet Radar, Sonar and Navigation},
Volume = {10},
Number = {4},
Pages = {689-698},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1049/iet-rsn.2015.0241},
Abstract = {In this study, the authors consider the adaptive detection
with multiple-input multiple-output radar in compound-
Gaussian clutter. The covariance matrices of the primary and
the secondary data share a common structure, but different
power levels (textures). A Bayesian framework is exploited
where both the textures and the structure are assumed to be
random. Precisely, the textures follow Gamma distribution or
inverse Gamma distribution and the structure is drawn from
an inverse complex Wishart distribution. In this framework,
two generalised likelihood ratio tests are derived. Finally,
they evaluate the capabilities of the proposed detectors
against compound-Gaussian clutter as well as their
superiority with respect to some existing
techniques.},
Doi = {10.1049/iet-rsn.2015.0241},
Key = {fds322883}
}
@article{fds321724,
Author = {Huang, WF and Ren, Y and Liu, QH},
Title = {Solid-Angle Error in the Magnetic-Field Integral Equation
for Perfectly Electric Conducting Objects},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {3},
Pages = {1158-1163},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {March},
url = {http://dx.doi.org/10.1109/TAP.2016.2518207},
Abstract = {For perfectly electric conducting (PEC) objects, one
difference between the electric-field integral equation
(EFIE) and the magnetic-field integral equation (MFIE) is
related to the solid angle, which only exists in the latter.
In this communication, the correct computation of
solid-angle contribution in MFIE is first summarized and
clarified. Through testing strictly inside triangles (TSIT)
and testing on edges (TOE) with or without the correct limit
value (CLV) for the solid-angle integral, six versions of
MFIE are then implemented by utilizing Rao-Wilton-Glisson
(RWG) functions for expansion and utilizing RWG or rotated
Buffa-Christiansen (BC) functions for testing. Based on the
simulations of typical sharp-edged targets and a sphere by
the EFIE and six MFIEs, it is found that using CLVs for the
solid-angle integral will improve the simulation accuracy
substantially in comparison to that with incorrect limit
values (ILVs). Moreover, if the singularities are properly
handled, the MFIE implemented by TSIT can achieve the same
accuracy with the MFIE implemented by TOE with
CLVs.},
Doi = {10.1109/TAP.2016.2518207},
Key = {fds321724}
}
@article{fds321723,
Author = {Liu, N and Cai, G and Zhu, C and Huang, Y and Liu, QH},
Title = {The Mixed Finite-Element Method With Mass Lumping for
Computing Optical Waveguide Modes},
Journal = {Ieee Journal of Selected Topics in Quantum
Electronics},
Volume = {22},
Number = {2},
Pages = {187-195},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {March},
url = {http://dx.doi.org/10.1109/JSTQE.2015.2473689},
Abstract = {A new mixed finite-element method is proposed for computing
the anisotropic, lossy, and open waveguide modes. By
incorporating Gauss' law into the vectorial wave equation,
the variational formulation is completely free of spurious
modes. It utilizes the curl-conforming linear tangential and
quadratic normal (LT/QN) edge elements to expand the
tangential component of the electric field, and the modified
nodal-based scalar basis functions to expand the
longitudinal component. A smaller scale generalized
eigenvalue problem is obtained by employing the mass lumping
technique. Numerical examples verify that the mixed
finite-element method with mass lumping is free of any
spurious eigenmode and has high efficiency.},
Doi = {10.1109/JSTQE.2015.2473689},
Key = {fds321723}
}
@article{fds322884,
Author = {Liu, Y and Chen, SL and Zhang, L and Liu, QH},
Title = {Determining the First-Null Mainlobe Region of an Arbitrary
Pattern for 2-D Numerical Pattern Synthesis
Algorithm},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {64},
Number = {3},
Pages = {1130-1136},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {March},
url = {http://dx.doi.org/10.1109/TAP.2016.2515135},
Abstract = {Determining the mainlobe region of an arbitrary pattern is a
critical problem in the two-dimensional numerical pattern
synthesis (2-D-NPS) method in which a number of artificial
interferences with appropriate powers are distributed
outside of the mainlobe region. In this communication, a
novel mainlobe region determination procedure based on the
seeded region growing (SRG) method is proposed. Two
different stopping criterions are introduced. Several
numerical synthesis examples for uniformly and nonuniformly
spaced planar arrays as well as a cylindrical array with
directive elements, are presented to validate the
effectiveness of the 2-D-NPS with the proposed mainlobe
determination procedure. The two stopping criterions are
also compared with these examples.},
Doi = {10.1109/TAP.2016.2515135},
Key = {fds322884}
}
@article{fds323109,
Author = {Xiao, Y and Ye, L and Cai, G and Liu, QH},
Title = {A full Ka-band half height waveguide to microstrip
transition},
Journal = {Asia Pacific Microwave Conference Proceedings,
Apmc},
Volume = {1},
Publisher = {IEEE},
Year = {2016},
Month = {February},
ISBN = {9781479987658},
url = {http://dx.doi.org/10.1109/APMC.2015.7411580},
Abstract = {In this paper, a full Ka-band transition from half height
rectangular waveguide to microstrip transmission line is
designed and optimized. A stepped impedance microstrip probe
is adopted to realize good impedance matching. By using
ANSYS HFSS simulation and optimization, the designed
transition has insert loss < 0.25dB and return loss > 15dB
during full Ka band. In the frequency band of 26.5 to 37GHz,
insert loss is maintained below 0.15dB and return loss is
maintained upon 20dB. This half height rectangular waveguide
to microstrip transition not only has high performance but
also has the advantage of much smaller size than
conventional one, which may have potential amplications in
comnact Ka-band integrated circuits and systems.},
Doi = {10.1109/APMC.2015.7411580},
Key = {fds323109}
}
@article{fds314357,
Author = {Jiang, W and Liu, N and Yue, Y and Liu, QH},
Title = {Mixed Finite-Element Method for Resonant Cavity Problem with
Complex Geometric Topology and Anisotropic Lossless
Media},
Journal = {Ieee Transactions on Magnetics},
Volume = {52},
Number = {2},
Pages = {1-8},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {February},
ISSN = {0018-9464},
url = {http://dx.doi.org/10.1109/TMAG.2015.2472366},
Abstract = {Electromagnetic eigenvalue problems are contaminated by
nonphysical zero modes in the conventional finite-element
method (FEM) with edge elements. Here, we investigate the
cavities with anisotropic lossless media, complex geometry
structure, and perfect electric conductor (PEC) walls and
eliminate all nonphysical zero and nonzero modes
successfully. We introduce a Lagrangian multiplier to deal
with the constraint of divergence-free condition. Our method
is based on the mixed FEM employing the first-order edge
basis functions to expand electric field and linear element
basis functions to expand Lagrangian multiplier. The
validity of our method is confirmed by several numerical
experiments. Meanwhile, the numerical experiments show that
when the cavity has a connected boundary, there is no
physical zero mode; when the cavity has several disconnected
boundaries, then the number of physical zero modes is equal
to one less than the number of disconnected PEC
boundaries.},
Doi = {10.1109/TMAG.2015.2472366},
Key = {fds314357}
}
@article{fds321725,
Author = {Song, Z and Zhang, L and Liu, QH},
Title = {High-Efficiency Broadband Cross Polarization Converter for
Near-Infrared Light Based on Anisotropic Plasmonic
Meta-surfaces},
Journal = {Plasmonics},
Volume = {11},
Number = {1},
Pages = {61-64},
Publisher = {Springer Nature},
Year = {2016},
Month = {February},
url = {http://dx.doi.org/10.1007/s11468-015-0027-y},
Abstract = {We show that the linear polarization state of
electromagnetic waves at near-infrared frequencies can be
efficiently rotated to its orthogonal direction by an
alternative design of anisotropic plasmonic meta-surfaces.
Numerical results demonstrate that the reflection
coefficient converting to cross polarization after
reflection can be as high as ~96 % with a half-powered
bandwidth ~40 % at the wavelength ~1.5 μm. The designed
system is much thinner than conventional geometric-optics
devices and does suffer little energy loss. The energy loss
is ~10 % at the designed wavelength due to the Ohmic loss
within the metals.},
Doi = {10.1007/s11468-015-0027-y},
Key = {fds321725}
}
@article{fds315034,
Author = {Cai, G and Li, W and Chen, Y and Liu, N and Song, Z and Liu,
QH},
Title = {Modeling and design of a plasmonic sensor for high sensing
performance and clear registration},
Journal = {Ieee Photonics Journal},
Volume = {8},
Number = {1},
Pages = {1-11},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {February},
url = {http://dx.doi.org/10.1109/JPHOT.2016.2520829},
Abstract = {A plasmonic sensor based on the nano-cylinder photonic
crystal slab is modeled and designed for the refractive
index sensing application. Design considerations and sensor
characteristics are explored in detail using the higher
order accuracy spectral element method. The geometrical
parameters of the designed plasmonic sensor are optimized.
With the shallowly etched configuration and the small radius
of the nano-cylinder, the sensor simultaneously achieves a
high sensing performance of figure of merit FoM=280 and a
clear registration of full-height/full-width at half-maximum
FH/FWHM=0.34nm-1for the lattice period P=750nm, the cylinder
radius r=85nm, and the cylinder thickness t=125 nm. The
proposed plasmonic sensor can find its great potential for
applications relying on detecting refractive
index.},
Doi = {10.1109/JPHOT.2016.2520829},
Key = {fds315034}
}
@article{fds322885,
Author = {Li, J and Song, L and Liu, QH},
Title = {Multiple Frequency Contrast Source Inversion Method for
Vertical Electromagnetic Profiling: 2D Simulation Results
and Analyses},
Journal = {Pure and Applied Geophysics},
Volume = {173},
Number = {2},
Pages = {607-621},
Publisher = {Springer Nature},
Year = {2016},
Month = {February},
url = {http://dx.doi.org/10.1007/s00024-015-1108-8},
Abstract = {A simultaneous multiple frequency contrast source inversion
(CSI) method is applied to reconstructing hydrocarbon
reservoir targets in a complex multilayered medium in two
dimensions. It simulates the effects of a salt dome
sedimentary formation in the context of reservoir
monitoring. In this method, the stabilized
biconjugate-gradient fast Fourier transform (BCGS-FFT)
algorithm is applied as a fast solver for the 2D volume
integral equation for the forward computation. The inversion
technique with CSI combines the efficient FFT algorithm to
speed up the matrix–vector multiplication and the stable
convergence of the simultaneous multiple frequency CSI in
the iteration process. As a result, this method is capable
of making quantitative conductivity image reconstruction
effectively for large-scale electromagnetic oil exploration
problems, including the vertical electromagnetic profiling
(VEP) survey investigated here. A number of numerical
examples have been demonstrated to validate the
effectiveness and capacity of the simultaneous multiple
frequency CSI method for a limited array view in
VEP.},
Doi = {10.1007/s00024-015-1108-8},
Key = {fds322885}
}
@article{fds323118,
Author = {Zhuang, M and Wei, S and Feng, N and Liu, N and Zhu, C and Liu, H and Zhou, J and Huang, Y and Luo, M and Yuan, M and Zhao, B and Liu,
QH},
Title = {New advances in FDTD methods for electromagnetic and elastic
waves for probing complex media},
Journal = {Proceedings of the 2015 Ieee 4th Asia Pacific Conference on
Antennas and Propagation, Apcap 2015},
Pages = {3-5},
Publisher = {IEEE},
Year = {2016},
Month = {January},
ISBN = {9781479988969},
url = {http://dx.doi.org/10.1109/APCAP.2015.7374249},
Abstract = {For modeling large-scale 3-D problems in electro-magnetic
and elastic waves in the probing of complex media, the
finite-difference time domain (FDTD) method is widely used.
However, there are still challenges in the high-frequency
regime and extremely low-frequency regime, as well as in the
accurate curved boundary treatment in this method. In this
work, we report several new improvements in the FDTD method
to address these challenging issues: (a) We have developed a
high-order FDTD method for elastic waves to greatly reduce
the numerical dispersion errors, and computer memory and CPU
time requirements, with a novel treatment of the free ground
boundary condition and the fluid-solid interface condition.
(b) We have proposed a new numerical method, finite volume
method and enlarged cell technique (ECT), to accurately and
efficiently implement the free-surface boundary conditions
in FDTD elastic wave simulations of an arbitrary
ground-surface topography. (c) We have developed an implicit
FDTD scheme that allows a time step increment many orders of
magnitude beyond the stability condition in the explicit
FDTD method for extremely low frequency electromagnetic
probing of subsurface, based on the Crank-Nicolson scheme
together with the perfectly matched layer. The efficacy of
these methods and their large scale applications will be
demonstrated in the presentation.},
Doi = {10.1109/APCAP.2015.7374249},
Key = {fds323118}
}
@article{fds283371,
Author = {Zheng, J and Su, T and Liu, H and Liao, G and Liu, Z and Liu,
QH},
Title = {Radar High-Speed Target Detection Based on the
Frequency-Domain Deramp-Keystone Transform},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {9},
Number = {1},
Pages = {285-294},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {January},
ISSN = {1939-1404},
url = {http://dx.doi.org/10.1109/JSTARS.2015.2453996},
Abstract = {In this paper, we propose a coherent detection algorithm for
high-speed targets by employing the parametric symmetric
autocorrelation function and the frequency-domain
deramp-keystone transform (FDDKT). This coherent detection
algorithm is an extension of the scaled inverse Fourier
transform (SCIFT)-based detection algorithm. However,
compared to the SCIFT-based detection algorithm, the
proposed coherent detection algorithm can acquire a better
antinoise performance and higher peak to sidelobe ratios
along the Doppler frequency and the scaled range cell.
Simulations and analyses for synthetic models and the real
radar data are provided to verify the effectiveness of the
proposed coherent detection algorithm.},
Doi = {10.1109/JSTARS.2015.2453996},
Key = {fds283371}
}
@article{fds314358,
Author = {Liang, Y and Guo, LX and Wu, ZS and Liu, QH},
Title = {A Study of Composite Electromagnetic Scattering from an
Object Near a Rough Sea Surface Using an Efficient Numerical
Algorithm},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {15},
Pages = {186-190},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {January},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2015.2437915},
Abstract = {The composite electromagnetic scattering problem from the
randomly rough sea surface and an object nearby is
effectively analyzed by the Extended Propagation-Inside-Layer
Expansion (EPILE) combined with the Forward-Backward method
(FBM) scheme. The formulation of the composite scattering is
given, the efficiency and accuracy of the adoptive algorithm
are verified, and several scattering characteristics under
various parameters are numerically analyzed.},
Doi = {10.1109/LAWP.2015.2437915},
Key = {fds314358}
}
@article{fds323111,
Author = {Zheng, J and Liu, H and Liao, G and Su, T and Liu, Z and Liu,
QH},
Title = {ISAR Imaging of Nonuniformly Rotating Targets Based on
Generalized Decoupling Technique},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {9},
Number = {1},
Pages = {520-532},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.1109/JSTARS.2015.2509169},
Abstract = {For nonuniformly rotating targets, such as targets with
complex motions and nonsevere maneuvering targets, the range
migration and the time-varying Doppler frequency deteriorate
inverse synthetic aperture radar (ISAR) image reconstructed
with the conventional range-Doppler (RD) algorithm. In this
paper, we focus on the scatterer-dependent Doppler spread
compensation and present an efficient ISAR imaging algorithm
for nonuniformly rotating targets by employing the symmetric
parametric instantaneous autocorrelation function (SPIAF)
and the generalized decoupling technique (GDT). It belongs
to the range-instantaneous-Doppler (RID) technique and can
be easily implemented by using the complex multiplication,
the fast Fourier transform (FFT) and the nonuniform FFT
(NUFFT). The implementation, the cross-Term, the
computational cost, and the antinoise performance are
analyzed for the GDT-based ISAR imaging algorithm. With the
synthetic data and the real radar data, comparisons with
other three representative ISAR imaging algorithms
demonstrate that the GDT-based ISAR imaging algorithm can
acquire a higher antinoise performance and a better
cross-Term suppression with a moderate computational cost.
In addition, with discussions of the characteristics, the
generalities and the implementation methods for the SPIAF
and the GDT, we indicate that these two new techniques may
be applied in more realistic applications.},
Doi = {10.1109/JSTARS.2015.2509169},
Key = {fds323111}
}
@article{fds323112,
Author = {Liu, L and Mao, Z and Zhang, J and Liu, N and Liu, QH},
Title = {The Influence of Vesicle Shape and Medium Conductivity on
Possible Electrofusion under a Pulsed Electric
Field.},
Journal = {Plos One},
Volume = {11},
Number = {7},
Pages = {e0158739},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.1371/journal.pone.0158739},
Abstract = {The effects of electric field on lipid membrane and cells
have been extensively studied in the last decades. The
phenomena of electroporation and electrofusion are of
particular interest due to their wide use in cell biology
and biotechnology. However, numerical studies on the
electrofusion of cells (or vesicles) with different deformed
shapes are still rare. Vesicle, being of cell size, can be
treated as a simple model of cell to investigate the
behaviors of cell in electric field. Based on the finite
element method, we investigate the effect of vesicle shape
on electrofusion of contact vesicles in various medium
conditions. The transmembrane voltage (TMV) and pore density
induced by a pulsed field are examined to analyze the
possibility of vesicle fusion. In two different medium
conditions, the prolate shape is observed to have selective
electroporation at the contact area of vesicles when the
exterior conductivity is smaller than the interior one;
selective electroporation is more inclined to be found at
the poles of the oblate vesicles when the exterior
conductivity is larger than the interior one. Furthermore,
we find that when the exterior conductivity is lower than
the internal conductivity, the pulse can induce a selective
electroporation at the contact area between two vesicles
regardless of the vesicle shape. Both of these two findings
have important practical applications in guiding
electrofusion experiments.},
Doi = {10.1371/journal.pone.0158739},
Key = {fds323112}
}
@article{fds323113,
Author = {Zhang, J and Zhao, X and Liu, QH},
Title = {Interactions between C60 and vesicles: A
coarse-grained molecular dynamics simulation},
Journal = {Rsc Adv.},
Volume = {6},
Number = {93},
Pages = {90388-90396},
Publisher = {Royal Society of Chemistry (RSC)},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.1039/c6ra13587k},
Abstract = {The interaction of fullerene with biological systems has
been an issue of great research interest for the past
decade. Mechanisms of C60 penetrating and disrupting cell
membranes have been widely investigated but are not fully
understood. Here we report on coarse grained molecular
dynamics (CGMD) simulations of the translocation of
monomeric C60 and a fullerene pair across a model DPPC
(dipalmitoylphosphatidylcholine) vesicle. Our simulations
suggest that monomeric C60 tends to dwell between the head
groups of the inner leaflet of the vesicle. This
characteristic can be verified from the PMF profiles and the
Lennard-Jones interaction energy analysis. The fullerene
pair can enter the vesicle membrane as a whole, then
disaggregate on a nanosecond timescale inside the membrane.
To study the toxicity of C60 on the vesicle, the
interactions of the fullerene aggregations with the vesicle
are also examined in our simulations. Small fullerene
aggregations can penetrate into the vesicle membrane, and do
not cause significant mechanical damage to the vesicle
membrane. However, as the size of the aggregations increases
to greater than the thickness of the vesicle membrane, this
can induce a change in the structure of the vesicle membrane
or even lead to rupture of the vesicle. Our simulations
describe the mechanism for the interactions of C60 with the
vesicle, and point out the potential toxicity of fullerenes
on the vesicle. These results may provide a useful blue
print for drug or gene delivery, and improve our
understanding of fullerene cytotoxicity.},
Doi = {10.1039/c6ra13587k},
Key = {fds323113}
}
@article{fds323096,
Author = {Xu, KD and Li, XS and Guo, YJ and Liu, QH},
Title = {Simple memristive SPICE macro-models and reconfigurability
in filter and antenna},
Journal = {Radioengineering},
Volume = {25},
Number = {4},
Pages = {700-706},
Publisher = {Brno University of Technology},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.13164/re.2016.0700},
Abstract = {Simple current- and voltage-controlled memristive circuit
macro-models using SPICE are proposed to capture the
nonlinear hysteresis loop behaviors in this paper. Different
current-voltage characteristics are investigated by applying
sinusoidal-wave, triangular-wave and square-wave source,
respectively. Furthermore, using finite-difference
time-domain (FDTD) emulator incorporated with a SPICE
circuit solver, the current- or voltagecontrolled memristive
SPICE model is embedded into a planar microwave bandstop
filter (BSF) and an ultrawideband (UWB) monopole antenna,
which connects two ends of the half-wavelength open-loop
resonator and two sides of the U-slot in the radiating
patch, respectively. The reconfigurability of the BSF and
antenna notched band can be achieved by switching the states
of the memristor.},
Doi = {10.13164/re.2016.0700},
Key = {fds323096}
}
@article{fds321726,
Author = {Liu, S and Zhao, Z and Zhu, X and Wang, Z and Song, J and Wang, B and Gong, Y and Nie, Z and Liu, QH},
Title = {Analysis of short pulse impacting on microwave induced
thermo-acoustic tomography},
Journal = {Progress in Electromagnetics Research C},
Volume = {61},
Pages = {37-46},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.2528/PIERC15100902},
Abstract = {Microwave induced thermo-acoustic tomography (MITAT) is a
developing technique for biomedical applications, especially
for early breast cancer detection. In this paper, impacts of
short microwave pulse on thermo-acoustic (TA) signals are
analyzed and verified through some experimental comparisons.
In these experiments, short microwave pulses with widths of
10 ns and 500 ns are employed as radiation resources. TA
signals generated from a cubic sample are analyzed in both
time- and frequency-domain. A trapezoid sample is also
performed for experimental comparing. Different from
previous literature, the effects of rising edge of radiation
microwave pulse have been intensively studied. Experimental
results demonstrate that shorter rising edge duration
conducts broader bandwidth of TA signal, which give rise to
better spatial resolution for tomography
imaging.},
Doi = {10.2528/PIERC15100902},
Key = {fds321726}
}
@article{fds321727,
Author = {Liu, Y and You, P and Zhu, C and Tan, X and Liu, QH},
Title = {Synthesis of sparse or thinned linear and planar arrays
generating reconfigurable multiple real patterns by
iterative linear programming},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {155},
Pages = {27-38},
Publisher = {EMW Publishing},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.2528/PIER15120401},
Abstract = {It is shown in this paper that the problem of reducing the
number of elements for multiplepattern arrays can be solved
by a sequence of reweighted ℓ1 optimizations under
multiple linear constraints. To do so, conjugate symmetric
excitations are assumed so that the upper and lower bounds
for each pattern can be formulated as linear inequality
constraints. In addition, we introduce an auxiliary variable
for each element to define the common upper bound of both
the real and imaginary parts of multiple excitations for
different patterns, so that only linear inequality
constraints are required. The objective function minimizes
the reweighted ℓ1-norm of these auxiliary variables for
all elements. Thus, the proposed method can be efficiently
implemented by the iterative linear programming. For
multiple desired patterns, the proposed method can select
the common elements with multiple set of optimized
amplitudes and phases, consequently reducing the number of
elements. The radiation characteristics for each pattern,
such as the mainlobe shape, response ripple, sidelobe level
and nulling region, can be accurately controlled. Several
synthesis examples for linear array, rectangular/triangular-grid
and randomly spaced planar arrays are presented to validate
the effectiveness of the proposed method in the reduction of
the number of elements.},
Doi = {10.2528/PIER15120401},
Key = {fds321727}
}
@article{fds331509,
Author = {Li, J and Zhu, J and Liu, QH},
Title = {Tunable properties of three-dimensional graphene-loaded
plasmonic absorber using plasmonic nano-particles},
Journal = {Materials Science Forum},
Volume = {860},
Pages = {29-34},
Publisher = {Trans Tech Publications},
Year = {2016},
Month = {January},
ISBN = {9783038357308},
url = {http://dx.doi.org/10.4028/www.scientific.net/MSF.860.29},
Abstract = {We demonstrate a three-dimensional nanostructure design by
combining graphene and conventional plasmonic
nanostructures, to achieve the high absorbance in the
visible region. Furthermore, the peak position and bandwidth
of graphene absorption spectra are tunable in a wide
wavelength range through a specific structural
configuration. Comparing the results of two structures which
is based on different materials, Gold and Silver. The
structure made of Silver present a better performance. These
results imply that graphene in combination with plasmonic
perfect absorbers have a promising potential for developing
advanced nanophotonic devices.},
Doi = {10.4028/www.scientific.net/MSF.860.29},
Key = {fds331509}
}
@article{fds322886,
Author = {LaBrecque, D and Brigham, R and Denison, J and Murdoch, L and Slack, W and Liu, QH and Fang, Y and Dai, J and Hu, Y and Yu, Z and Kleinhammes, A and Doyle, P and Wu, Y and Ahmadian, M},
Title = {Remote imaging of Proppants in hydraulic fracture networks
using electromagnetic methods: Results of small-scale field
experiments},
Journal = {Society of Petroleum Engineers Spe Hydraulic Fracturing
Technology Conference, Hftc 2016},
Year = {2016},
Month = {January},
ISBN = {9781613994382},
Abstract = {Copyright 2016, Society of Petroleum Engineers. The goal of
this project is to develop techniques for monitoring
hydraulic fractures in reservoirs by injecting electrically
conductive, dielectric, or magnetically permeable proppants.
The contrasts between the properties of the proppants and
the subsurface provided the basis for imaging using
geophysical methods. The initial experiments focused on a
series of small, shallow fractures; however, the goal of the
project is to develop methods applicable to oil-field
fractures. The project began by screening different proppant
types using laboratory and numerical analyses that have been
ongoing by researchers at the Advanced Energy Consortium
(AEC). This work identified Loresco coke breeze and steel
shot as materials that could create significant electrical
or magnetic contrasts with most geological formations. These
proppants were tested by creating hydraulic fractures in a
shallow field setting consisting of highly weathered
residual saprolite near Clemson University in western South
Carolina. Six hydraulic fractures were created in highly
monitored cells by injecting the contrasting proppants at a
depth of approximately 1.5 m. This created sub-horizontal
fractures filled with proppant approximately 10 mm thick and
extending 3 to 5 m in maximum dimension. Each cell had a
dense array of electrodes and magnetic sensors on the
surface, as well as four shallow vertical electrode arrays
that were used to obtain data before and after hydraulic
fracturing. Net vertical displacement, cores and trenching
were used to characterize the fracture geometries. Hydraulic
fracture geometries were estimated by inverting pre-and
post-injection geophysical data using various codes. Data
from cores and excavation show that the hydraulic fractures
formed a saucer-shape with a preferred propagation in the
horizontal direction. The geophysical inversions generated
images with remarkably similar form, size, and location to
the ground truth from direct observation. Displacement and
tilt data appear promising as a constraint on fracture
geometry.},
Key = {fds322886}
}
@article{fds322887,
Author = {Li, J and Guo, J and Zhang, A and Joines, WT and Liu,
QH},
Title = {Miniaturized single-feed cross-aperture coupled circularly
polarized microstrip patch antenna},
Journal = {Progress in Electromagnetics Research C},
Volume = {63},
Pages = {183-191},
Publisher = {EMW Publishing},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.2528/PIERC16031301},
Abstract = {A novel miniaturized single-feed cross-aperture coupled
circularly polarized (CP) microstrip patch antenna loaded by
four identical shorting strips is proposed and discussed.
Each shorting strip underneath the edges of the radiating
patch is connected to the ground plane via an array of three
identical and equidistant shorting pins. With the assistance
of the capacitance offered by the radiating patch and the
shorting strips, and the inductance induced by the shorting
pins, the patch size and overall size of the proposed
antenna have been significantly reduced by 75% and 69%,
respectively, compared with the conventional antenna. An
antenna prototype with an overall size of 50mm × 50mm ×
7.548mm (0.317λ0 × 0.317λ0 × 0.048λ0) and a patch size
of 29.43mm × 27.85mm (0.186λ0 × 0.176λ0) has been
fabricated and measured, which shows a measured 10-dB return
loss bandwidth of 92MHz (4.76%) from 1.886 to 1.978 GHz with
a maximum right-handed CP (RHCP) gain of 4.9 dBic. The
measured 3-dB axial ratio (AR) bandwidth is 28MHz (1.46%)
from 1.899 to 1.927 GHz with a 3-dB AR beamwidth of more
than 140° across the operating bandwidth.},
Doi = {10.2528/PIERC16031301},
Key = {fds322887}
}
@article{fds321728,
Author = {Liu, QH},
Title = {Microwave imaging and microwave induced thermoacoustic
tomography},
Journal = {2015 Ieee International Conference on Microwaves,
Communications, Antennas and Electronic Systems, Comcas
2015},
Publisher = {IEEE},
Year = {2015},
Month = {December},
ISBN = {9781479974733},
url = {http://dx.doi.org/10.1109/COMCAS.2015.7360431},
Abstract = {Breast cancer imaging by microwaves has been investigated
intensively over the past two decades due to the potentially
high electrical contrasts between malignant tumors and
normal breast tissue, but so far clinically successful
systems have been rare. We will describe challenges in
achieving such a system, and ways to improve the resolution
of microwave imaging. We will also report on our recent
progress in microwave induced thermoacoustic tomography
(MITAT) for breast imaging.},
Doi = {10.1109/COMCAS.2015.7360431},
Key = {fds321728}
}
@article{fds321729,
Author = {Zhang, Y and Zhao, Z and Nie, Z and Liu, QH},
Title = {Full-polarisation three-dimensional pattern synthesis for
conformal conical arrays with dynamic range ratio constraint
by using the initialisations based on equivalence
theorem},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {9},
Number = {15},
Pages = {1659-1666},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1049/iet-map.2015.0273},
Abstract = {To design three-dimensional (3D) conformal conical arrays
with desired 3D co-polarisation and crosspolarisation
radiation patterns, a pattern synthesis method based on
equivalent principle and trust region method is presented.
Dynamic range ratio (DRR) of element excitations is taken
into consideration. An analytical function is utilised to
constrain DRR and avoid discontinuity of objective function.
Owing to the optimisation is based on very good initial
currents distribution, the optimisation procedure is very
fast. The analytical gradient and Hessian matrix expressions
of the objective function are derived. This also improves
the optimisation efficiency compared with using the finite
difference methods to solve gradient and Hessian matrix. To
demonstrate the effectiveness of this proposed method, a
conformal conical array with 454 elements has been designed.
The amplitude and phase excitations were optimised by using
the proposed method.},
Doi = {10.1049/iet-map.2015.0273},
Key = {fds321729}
}
@article{fds283388,
Author = {Zhang, Y and Feng, N and Zheng, HH and Liu, QH},
Title = {A corner-free truncation strategy for FDTD method in target
scattering},
Journal = {Journal of Computational Physics},
Volume = {302},
Pages = {567-572},
Publisher = {Elsevier BV},
Year = {2015},
Month = {December},
ISSN = {0021-9991},
url = {http://dx.doi.org/10.1016/j.jcp.2015.08.050},
Abstract = {In this paper, the corner-free truncation (CFT) strategy is
proposed to terminate the circular boundary out of
finite-difference time-domain (FDTD) region. Using the
principle of reflection-free optimal thin film, the
permittivity ε and the permeability μ have been extended
to the complex field. The electric conductivity σe and the
equivalent magnetic loss σm relate to the complex value and
are suitable for the impedance-matched condition (IMC). The
propagation wave can be absorbed well at the circular
boundary. Moreover, computational efficiency has been much
enhanced when those useless square-corners have been
eliminated by using the proposed method. In TMz wave, the
sinusoidal wave is set near the circular boundary. Applying
the CFT strategy, the Ez amplitudes and phases show the
concentric circles in the different timesteps. Compared with
the square PML, numerical experiments in near- and far-field
have come to the fulfillment. At the same numerical example,
the CFT strategy has higher accuracy than the conformal PML.
These results have fully verified the effectiveness of the
proposed algorithm.},
Doi = {10.1016/j.jcp.2015.08.050},
Key = {fds283388}
}
@article{fds314356,
Author = {Ding, X and Zhao, Z and Yang, Y and Zhou, L and Ouyang, J and Liu,
QH},
Title = {Broadband unidirectional printed antenna with quad-folded
dipoles for circular polarization},
Journal = {Microwave and Optical Technology Letters},
Volume = {57},
Number = {12},
Pages = {2871-2876},
Publisher = {WILEY},
Year = {2015},
Month = {December},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.29465},
Abstract = {In this article, a broadband unidirectional printed antenna
with quad-folded dipoles for circularly polarized radiation
is proposed. The antenna consists of a trapezoidal feed
structure, an annular transmission line and quad-folded
dipoles. An 80 × 80 mm2 reflector is used to achieve
unidirectional radiation. Measured results indicate that the
proposed design achieves an impedance bandwidth of 37.1%
(1.82-2.65 GHz) for the voltage standing wave ratio <2.0 and
a 3 dB axial ratio bandwidth of 35% (1.84-2.62 GHz),
covering the third-generation (3G, 1880-2125 MHz)/long-term
evaluation (1880-2400 MHz)/wireless local area network
(2400-2480 MHz) bands. An average gain of 6.3 dBic is
obtained in the operating band.},
Doi = {10.1002/mop.29465},
Key = {fds314356}
}
@article{fds321731,
Author = {Yu, Z and Zhang, W and Liu, QH},
Title = {The Mixed-Order BCGS-FFT Method for the Scattering of
Three-Dimensional Inhomogeneous Anisotropic
Magnetodielectric Objects},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {12},
Pages = {5709-5717},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1109/TAP.2015.2496104},
Abstract = {This paper presents the first FFT-based fast volume integral
equation solver for inhomogeneous anisotropic
magnetodielectric objects. The volume integral equations are
formulated by employing mixed-order basis functions that
expand the flux densities and vector potentials in the
coupled field integral equations in terms of different sets
of basis functions with different orders. Volumetric
roof-top basis functions are used for flux densities whereas
second-order curl conforming basis functions are used for
vector potentials. A fast volume integral equations solver
namely the BCGS-FFT method is then applied to accelerate the
solution of this mixed-order weak-form formulation. Examples
show that the mixed-order BCGS-FFT method has high accuracy
compared to both analytical and numerical solutions.
Examples also show the mixed-order BCGS-FFT method has high
computational efficiency compared to commercial
software.},
Doi = {10.1109/TAP.2015.2496104},
Key = {fds321731}
}
@article{fds321730,
Author = {Cai, Y and Zhu, J and Liu, QH and Lin, T and Zhou, J and Ye, L and Cai,
Z},
Title = {Enhanced spatial near-infrared modulation of graphene-loaded
perfect absorbers using plasmonic nanoslits.},
Journal = {Optics Express},
Volume = {23},
Number = {25},
Pages = {32318-32328},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1364/oe.23.032318},
Abstract = {Modulating spatial near-infrared light for ultra-compact
electro-optic devices is a critical issue in optical
communication and imaging applications. To date, spatial
near-infrared modulators based on graphene have been
reported, but they showed limited modulation effects due to
the relatively weak light-graphene interaction. In
combination with graphene and metallic nanoslits, we design
a kind of ultrathin near-infrared perfect absorber with
enhanced spatial modulation effects and independence on a
wide range of incident angles. The modulated spectral shift
of central wavelength is up to 258.2 nm in the near-infrared
range, which is more promising in applications than
state-of-the-art devices. The modulation enhancement is
attributed to the plasmonic nanoslit mode, in which the
optical electric field is highly concentrated in the deep
subwavelength scale and the light-graphene interaction is
significantly strengthened. The physical insight is deeply
revealed by a combination of equivalent circuit and
electromagnetic field analysis. The design principles are
not only crucial for spatial near-infrared modulators, but
also provide a key guide for developing active near-infrared
patch nanoantennas based on graphene.},
Doi = {10.1364/oe.23.032318},
Key = {fds321730}
}
@article{fds322888,
Author = {Zhu, J and Li, D and Yan, S and Cai, Y and Liu, QH and Lin,
T},
Title = {Tunable microwave metamaterial absorbers using
varactor-loaded split loops},
Journal = {Epl (Europhysics Letters)},
Volume = {112},
Number = {5},
Pages = {54002-54002},
Publisher = {IOP Publishing},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1209/0295-5075/112/54002},
Abstract = {Currently, implementation of active circuit elements within
metamaterials is an effective way to make them electrically
tunable. We combine varactors with split copper loops in a
metamaterial absorber in order to obtain an electrically
tunable microwave response. This absorber has a compact
planar structure and a simplified back feeding network.
Flexible frequency tunability of the microwave reflection in
the range of 5-6 GHz is experimentally achieved. The design,
simulation, and experimental results are systematically
presented. The proposed method is scalable for developing
active metamaterial absorbers based on metal loops, and
shows a promising potential of active metamaterial absorbers
for extensive microwave applications.},
Doi = {10.1209/0295-5075/112/54002},
Key = {fds322888}
}
@article{fds322889,
Author = {Sun, Q and Tobon, LE and Ren, Q and Hu, Y and Liu, QH},
Title = {Efficient noniterative implicit time-stepping scheme based
on e and B fields for sequential DG-FETD
systems},
Journal = {Ieee Transactions on Components, Packaging and Manufacturing
Technology},
Volume = {5},
Number = {12},
Pages = {1839-1849},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1109/TCPMT.2015.2496192},
Abstract = {The discontinuous Galerkin finite-element time-domain
(DG-FETD) method with implicit time integration has an
advantage in modeling electrically fine-scale
electromagnetic problems. Based on domain decomposition
methods, it avoids the direct inversion of a large system
matrix as in the conventional FETD method; by employing
implicit time integration, it obviates an extremely small
time-step interval to maintain stability as in explicit
schemes. Based on curl-conforming basis functions for the
electric field intensity E field and divergence-conforming
basis functions for the magnetic flux density B field, a new
noniterative implicit time-stepping scheme is proposed to
efficiently solve sequentially ordered systems for
electrically fine-scale problems. Compared with the previous
EH-based scheme, the new scheme introduces fewer unknowns
and, thereby, results in a smaller matrix system. Based on
the Crank-Nicholson algorithm for time integration, the
matrix system is in a block tridiagonal form. Then, through
separating the surface unknowns from the volume unknowns, a
block lower-diagonal-upper (LDU) decomposition is
implemented, reducing the computational complexity of the
original system. The adaptivity of parallel computing in
subdomain level during preprocessing further helps shorten
the computation time. Numerical results confirm that the
proposed LDU scheme presents improved efficiency in terms of
memory and CPU time while retaining the same accuracy,
compared with the previous implicit block-Thomas method.
With respect to the explicit Runge-Kutta method and the
standard FDTD, it also shows an advantage in CPU time. The
proposed scheme will help improve the performance of DG-FETD
in modeling electrically fine-scale problems.},
Doi = {10.1109/TCPMT.2015.2496192},
Key = {fds322889}
}
@article{fds322890,
Author = {Liu, Y and Zhang, L and Ye, L and Nie, Z and Liu, QH},
Title = {Synthesis of sparse arrays with frequency-invariant-focused
beam patterns under accurate sidelobe control by iterative
second-order cone programming},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {12},
Pages = {5826-5832},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {December},
url = {http://dx.doi.org/10.1109/TAP.2015.2478908},
Abstract = {It is shown in this communication that the problem of
synthesizing a frequency-invariant (FI) beam pattern with as
few elements as possible can be transformed into a sequence
of weighted ℓ1 optimizations under multiple convex
constraints. The objective of the weighted ℓloptimization
is to minimize the number of radiating elements. For the
filter-and-sum beamforming structure, this is equivalent to
minimizing the number of filters, each with a set of
optimized coefficients. The multiple constraints are adopted
to individually control the mainlobe and sidelobe pattern
characteristics, so as to preserve the FI property in the
mainlobe region while satisfying a given upper bound in the
sidelobe region. The WNG constraint can also be incorporated
into the proposed method to enhance the synthesis
robustness. This method can be easily implemented by
iterative second-order cone programming (SOCP), and only few
iterations are required to reach the convergence. A set of
examples for the synthesis of FI patterns with uniform
sidelobe level (SLL) or multiple nulls, scannable FI
patterns, and the synthesis of FI pattern for an arc array
with directive elements, is presented to validate the
effectiveness and advantages of the proposed method. The
element saving is about 23.3%-50% for the test
cases.},
Doi = {10.1109/TAP.2015.2478908},
Key = {fds322890}
}
@article{fds321732,
Author = {Xiong, X and Liu, Y and Yao, Z and Zhang, L and Li, W and Liu,
QH},
Title = {A novel phase shifting surface-integrated horn
antenna},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Advanced Materials and Processes for Rf and Thz
Applications, Ieee Mtt S Imws Amp 2015 Proceedings},
Publisher = {IEEE},
Year = {2015},
Month = {November},
ISBN = {9781479964505},
url = {http://dx.doi.org/10.1109/IMWS-AMP.2015.7324898},
Abstract = {We present the design of a phase shifting surface-integrated
horn antenna (PSSIHA) which consists of the horn antenna and
planar array lens. Planar array lens just needs one type of
antenna-filter-antenna element and is applied to obtain a
relatively uniform phase distribution on the aperture of the
horn antenna. The PSSIHA prototype has been fabricated.
Measured results match with simulated ones well. The PSSIHA
achieves a higher gain and a better directivity than the
horn without the lens.},
Doi = {10.1109/IMWS-AMP.2015.7324898},
Key = {fds321732}
}
@article{fds321733,
Author = {Zhang, L and Liu, Y and Ye, L and Liu, H and Liu, QH},
Title = {Dynamic co-polarization decoupling method using tunable
resonators},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Advanced Materials and Processes for Rf and Thz
Applications, Ieee Mtt S Imws Amp 2015 Proceedings},
Publisher = {IEEE},
Year = {2015},
Month = {November},
ISBN = {9781479964505},
url = {http://dx.doi.org/10.1109/IMWS-AMP.2015.7324990},
Abstract = {A novel method of decoupling two closely placed co-polarized
antennas is presented in this work. Two co-polarization
monopoles are placed at the same elevation with a distance
of 0.8 λ. Eight rows of varactors based tunable resonators
are placed between them. By tuning the bias voltage of the
eight rows, the amplitude and phase responses are altered.
Correspondingly, the near field distribution is manipulated.
Thus a high-level port to port isolations is realized. The
measured results show that the transmission coefficient is
suppressed to -110 dB, when the direct transmission
coefficient (nothing is between the monopoles) is about -27
dB, and when a same dimension metal plate is installed it is
-50.0 dB. Furthermore, this high-level isolation is tunable.
We realize similar results from 2.0 GHz to 2.6
GHz.},
Doi = {10.1109/IMWS-AMP.2015.7324990},
Key = {fds321733}
}
@article{fds321734,
Author = {Zhang, L and Liu, Y and Ye, L and Liu, H and Liu, QH},
Title = {A horizontally polarized 360-degree radiation pattern
steerable antenna based on active frequency selective
surface},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Advanced Materials and Processes for Rf and Thz
Applications, Ieee Mtt S Imws Amp 2015 Proceedings},
Publisher = {IEEE},
Year = {2015},
Month = {November},
ISBN = {9781479964505},
url = {http://dx.doi.org/10.1109/IMWS-AMP.2015.7324933},
Abstract = {The possibility of building horizontally polarized,
electronically steerable antenna by using active frequency
selective surface is investigated. A 10-element
electronically steerable antenna is realized by using an
omni-directional Alford-loop antenna and active frequency
selective surface columns with horizontal polarization
sensitive direction. This antenna working at 2.4 GHz WiFi
band is 360-degree steerable, and 1.7 dBi additional gain is
achieved compared with the original Alford-loop
antenna.},
Doi = {10.1109/IMWS-AMP.2015.7324933},
Key = {fds321734}
}
@article{fds321735,
Author = {Yu, F and Zhang, L and Ye, L and Liu, Y and Liu, QH},
Title = {Cost Efficiency Adaptive Antenna System Based on Active
Frequency Selective Surface},
Journal = {2015 Ieee International Conference on Ubiquitous Wireless
Broadband, Icuwb 2015},
Publisher = {IEEE},
Year = {2015},
Month = {November},
ISBN = {9781467365550},
url = {http://dx.doi.org/10.1109/ICUWB.2015.7324432},
Abstract = {A patent-pending 16 channel adaptive antenna based on active
frequency selective surface is proposed. A Zigbee system
built with this antenna is realized and tested in the real
world. And serial experiments are taken. The results show
that this antenna has a better performance than a pair of
dipoles. At some places, this antenna can offer a stable
link when the dipoles based system loses many packages. And
for some places, this antenna can offer a 20 dB better
received signal strength.},
Doi = {10.1109/ICUWB.2015.7324432},
Key = {fds321735}
}
@article{fds315032,
Author = {Yao, Z and Liu, Y and Yu, Z and Xiong, X and Zhang, L and Ye, L and Liu,
QH},
Title = {A low-profile aperture impedance matching technique for TEM
planar Luneberg lens},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Advanced Materials and Processes for Rf and Thz
Applications, Ieee Mtt S Imws Amp 2015 Proceedings},
Publisher = {IEEE},
Year = {2015},
Month = {November},
ISBN = {9781479964505},
url = {http://dx.doi.org/10.1109/IMWS-AMP.2015.7325028},
Abstract = {A novel low-profile aperture impedance matching technique of
TEM Luneberg lens is presented. The trapezoidal strips at
the edge of the lens is the impedance matching transition
from the lens to the free space. In order to verify this
method, a TEM mode Luneberg lens antenna over the 60-61 GHz
at V-band is manufactured by using metamaterial surfaces.
The refractive index of the lens is extracted by the novel
S-parameter retrieval method. An inverted L probe antenna is
used as the feeding structure which can excitate the TEM
mode electromagnitic wave between the metal plate and the
metamaterial surface, and this architecture is easy to
produce. The matching structure improved the SLL (sidelobe
level) with a 2 dB drop, so the far-field radiation pattern
operates a good performance around the desired frequency
band, which verified the validity of the aperture impedance
matching technique.},
Doi = {10.1109/IMWS-AMP.2015.7325028},
Key = {fds315032}
}
@article{fds322893,
Author = {Ren, Q and Liu, QH},
Title = {EB scheme hybrid spectral-finite element time domain method
for super multiscale simulations},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2015-October},
Pages = {179-180},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978151},
url = {http://dx.doi.org/10.1109/APS.2015.7304475},
Abstract = {A hybrid discontinuous Galerkin spectral element and finite
element time domain (DG-SE/FETD) method for the first-order
Maxwell's equations is proposed in this study. It uses EB to
replace the EH scheme in earlier research. The discontinuous
Galerkin method is employed for domain decomposition.
Non-conformal mesh allows not only an abrupt change of
element size but also different element type across the
interfaces between adjacent subdomains. Compared to EH
scheme, the EB scheme has less DoFs, consequently, consumes
less CPU time and memory. This new DG-SE/FETD method has
been successfully applied to multiscale problems.},
Doi = {10.1109/APS.2015.7304475},
Key = {fds322893}
}
@article{fds322894,
Author = {Sun, Q and Liu, QH},
Title = {New 3D hybrid FDTD-FETD method with non-conformal
mesh},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2015-October},
Pages = {1826-1827},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978151},
url = {http://dx.doi.org/10.1109/APS.2015.7305302},
Abstract = {A new efficient 3D hybrid FDTD-FETD method is proposed to
exploit the advantages of FDTD and FETD for electromagnetic
modeling. The proposed method implements the hybrid of FDTD
and FETD with a buffer region and allows non-conformal mesh
for spatial discretization, which preserves the mesh
flexibility as in FETD and thus facilitates the hybrid
method for practical application. Furthermore, discontinuous
Galerkin method is employed to realize field communication
at the interface between the non-conformal mesh in different
subdomains. Finally, numerical results are shown to validate
the proposed hybrid method and demonstrate its flexibility
for modeling cases with fine structures.},
Doi = {10.1109/APS.2015.7305302},
Key = {fds322894}
}
@article{fds322891,
Author = {Niu, J and Liu, QH and Luo, M},
Title = {Full-wave third harmonic generation analyses of
graphene-based optoelectronic devices},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2015-October},
Pages = {1646-1647},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978151},
url = {http://dx.doi.org/10.1109/APS.2015.7305212},
Abstract = {Over the past decades, a few prototype of graphene-based
optoelectronic devices have been proposed because of
graphene's remarkable optical and mechanical properties.
However, few tools are available for analyzing graphene's
nonlinear optical performance within practical designs,
despite its strong third harmonic generation (THG) has drawn
intensive attention in theoretical and experimental study.
In this work, a full-wave solver is proposed for the THG
problem. Based on boundary-integral spectral element
solvers, the proposal numerical method shows relatively fast
convergence and high accuracy. In addition, as a typical
example, several prototypes of graphene-based photodetectors
are studied for their THG emission as stored
energy.},
Doi = {10.1109/APS.2015.7305212},
Key = {fds322891}
}
@article{fds322892,
Author = {Niu, J and Liu, QH and Luo, M and Zhu, J},
Title = {Enhanced surface plasmonic optical absorption engineering of
graphene: Simulation by boundary-integral spectral element
method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2015-October},
Pages = {1644-1645},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978151},
url = {http://dx.doi.org/10.1109/APS.2015.7305211},
Abstract = {Graphene's relatively poor absorption is an essential
obstacle for designing graphene-based photonic devices with
satisfying photo-responsivity. To enhance the tunable light
absorption of graphene, appropriate excitation of localized
surface plasmon resonance is considered as a promising
approach. In this work, the strategy of incorporating
periodic cylindrical gold nanoparticle (NP) cluster arrays
with Bragg reflectors into graphene-based photodetectors are
theoretically studied by the boundary-integral spectral
element method (BI-SEM). With the BI-SEM, the models can be
numerically analyzed with excellent accuracy and efficiency.
Numerical simulation shows that the proposed structures can
effectively engineer the light absorption in graphene by
tuning plasmon resonance. In the spectra of 300 nm to 1000
nm, a maximum light absorption of 76.13% is observed for the
graphene layer with optimal parameters of the photodetector
model, while that of 54.68% is observed at the edge of
visible spectra.},
Doi = {10.1109/APS.2015.7305211},
Key = {fds322892}
}
@article{fds321742,
Author = {Yu, Z and Liu, QH},
Title = {A mixed order BCGS-FFT based fast 3D inverse electromagnetic
scatterings for anisotropic objects},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {60},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303344},
Abstract = {The purpose of the electromagnetic (EM) inverse scattering
problems is to estimate EM properties of unknown objects
within area of interest with known scattered EM fields.
Three dimensional inverse scattering problems can be
conveniently modeled by volume equivalence theorem. The
volume equivalence theorem describes the forward scattering
problems by volume integral equations. Estimating unknown EM
properties of objects from these volume integral equations
is a nonlinear problem. The born iterative method (BIM) and
the distorted born iterative method (DBIM) are proposed to
efficiently solve the nonlinear problems (Y.M. Wang and W.C.
Chew Int. Jour. Imaging Sys. Tech. 1, 100-108, 1989). The
BIM is more stable with noisy data and the DBIM converges
faster.},
Doi = {10.1109/USNC-URSI.2015.7303344},
Key = {fds321742}
}
@article{fds321741,
Author = {Yu, Z and Zhou, J and Fang, Y and Hu, Y and Liu, QH},
Title = {Contrast enhanced through casing hydraulic fractures
mapping},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {58},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303342},
Abstract = {Hydraulic fracturing is being performed in more than 60
years in more than a million wells and counting. Despite the
long history in hydraulic fracturing, the growth of
fractures over time is not well understood. The creation of
hydraulic fractures can be monitored in real time via
micro-seismic method. However, this method is only effective
during fracturing process. After hydraulic fractures are
created, the growth of fractures remains unknown. There is a
lack of methods to effectively characterize fractures in the
post fracturing period.},
Doi = {10.1109/USNC-URSI.2015.7303342},
Key = {fds321741}
}
@article{fds321737,
Author = {Yu, Z and Liu, QH},
Title = {A fast volume integral equation solver for electromagnetic
simulation with complex voxel based magnetodielectric human
model in MRI applications},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Rf and Wireless Technologies for Biomedical and Healthcare
Applications, Imws Bio 2015 Proceedings},
Pages = {90-91},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479985432},
url = {http://dx.doi.org/10.1109/IMWS-BIO.2015.7303792},
Abstract = {This work presents a fast volume integral equation solver
named the mixed order BCGS-FFT method for electromagnetic
simulations of high resolution human bodies with both
dielectric and magnetic susceptibility contrasts in MRI
application. The mixed order BCGS-FFT method is an accurate
and efficient solver developed for magnetodielectric
objects. A numerical calculation of the electromagnetic
responses of a high resolution voxel human head model shows
a high efficiency of the mixed order BCGS-FFT method in both
computational complexity and memory requirement.},
Doi = {10.1109/IMWS-BIO.2015.7303792},
Key = {fds321737}
}
@article{fds321738,
Author = {Fang, Y and Zhou, J and Yu, Z and Hu, Y and Liu, QH},
Title = {Application of BCGS-FFT and distorted born approximation for
hydraulic fracturing detection and imaging},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {273},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303557},
Abstract = {With the ever increasing number of research on hydraulic
fracture aiming at improved oil production, forward and
inverse solvers based on electromagnetic method to detect
and reveal properties of hydraulic fracture have become an
important subject of research. Most of existing forward and
inverse methods are developed to simulate the well logging
model, such as Method of Moments (MoM) and Born
Approximation. Those methods have the advantages to
reconstruct the geometrical and electromagnetic information
of formation. However, they are not fast enough and the
memory cost are large. Moreover, when those methods are used
to simulate hydraulic fractures, they are not able to obtain
the accurate result.},
Doi = {10.1109/USNC-URSI.2015.7303557},
Key = {fds321738}
}
@article{fds321739,
Author = {Sun, Q and Ren, Q and Liu, QH},
Title = {Efficient implicit-explict CN-LF time integration scheme for
hybrid FDTD-FETD},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {131},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303415},
Abstract = {Finite different time domain method (FDTD) is widely used
for transient electromagnetic field modeling. It shows great
computational efficiency by employing central differencing
for spatial discretization based on the staggered Cartesian
grid and Leap-frog time stepping for temporal
discretization. This method avoids matrix operations and
presents linear complexity. Thus it has robust adaptability
in practical application. One drawback of FDTD is the
staircasing error, due to the approximation of irregular
structures with the Cartesian grid. Another popular time
domain technique is finite element time domain method
(FETD), which features great meshing flexibility for fine
and complicated structures by employing unstructured
tetrahedron element. This method, through a matrix assembly
procedure, finally needs to solve a linear system, which
involves matrix inversion and can thus become
computationally costly, especially for large scale problems.
An ideal attempt is to realize hybrid of FDTD and FETD in a
way as follows: (1) for smoothly inhomogeneous regions and
the perfectly matched layers (PML) in open problems,
conventional FDTD is employed to reduce the overall number
of unknowns for spatial discretization and improve the
computational efficiency with explicit time integration
scheme; (2) for fine and complicated structures, FETD is
employed to eliminate the staircasing error and meanwhile
implicit time integration scheme is used to overcome the CFL
constraint. In this way, ideally we can take full advantages
of both FDTD and FETD while effectively avoiding their
limitations. This idea has attracted considerable attempts,
which facilitated the mature of the hybrid method for
practical application.},
Doi = {10.1109/USNC-URSI.2015.7303415},
Key = {fds321739}
}
@article{fds321740,
Author = {Dai, J and Liu, QH},
Title = {Fast calculation of the response of multicomponent induction
logging tool for hydraulic fracture and its
mapping},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {275},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303559},
Abstract = {Hydraulic fracturing is commonly employed in the wells of
tight oil and tight gas to increase exposure to the
producing formation, boosting the flow rate of hydrocarbon
into the wellbore, therefore, enhancing the productivity of
gas or petroleum. Knowledge of the information of hydraulic
fracture, such as dimensions, location, orientation and
conductivity of filled proppant, will facilitate selecting
locations for casing perforation and predicting
production.},
Doi = {10.1109/USNC-URSI.2015.7303559},
Key = {fds321740}
}
@article{fds321736,
Author = {Hu, Y and Zhang, W and Liu, Q},
Title = {Enhanced subsurface sensing with nanoparticles as contrast
agents for oil industry},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {274},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303558},
Abstract = {In recent years, the applications of nanotechnology have
been extensively researched in many key areas of oil
industry, such as exploration, drilling and production.
Nanomaterials can be developed as excellent imaging-contrast
agents in their magnetic and electric properties. They are
able to flush with the injection fluids through the
reservoir micro-size pores. Tracing these contrast agents
with electromagnetic tomography technology can potentially
help tracking the flood-front in waterflood, monitoring
enhanced oil recovery process and field characterization.},
Doi = {10.1109/USNC-URSI.2015.7303558},
Key = {fds321736}
}
@article{fds321746,
Author = {Niu, J and Luo, M and Liu, QH},
Title = {Full-wave nonlinear optical analyses of graphene-based
optoelectronic devices},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {155},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303439},
Abstract = {Graphene has drawn strong interest and intensive study
because of its remarkable electromagnetic, thermal, and
mechanical properties. As a crucial property, graphene's
nonlinear optical performance is an emerging topic in
theoretical and experimental studies. Recent investigations
shows that despite its one-atom thickness, single layer
graphene's nonlinear optical response is particularly
strong. Due to the centrosymmetric structure, the ideal
floating single layer graphene forbids the emission of
second harmonic generation (SHG) of optical fields. However,
in practical designs, the symmetric property may be broken
by its adjacent materials, which makes the induced SHG
optical behavior interesting. On the contrary, the third
order nonlinear optical effects in graphene are reported as
remarkably strong. Originated from the resonant nature of
the light-graphene interaction, the effective third-order
susceptibility arrives on the order of χ(3) ∼ 10-15m2/V2.
This strong third order optical interaction generates a
third harmonic signal with a significant contrast between
graphene and the background material in most optoelectronic
designs.},
Doi = {10.1109/USNC-URSI.2015.7303439},
Key = {fds321746}
}
@article{fds321747,
Author = {Dai, J and Liu, QH},
Title = {Sensitivity analysis of hydraulic fracture in open and cased
holes using numerical mode matching method},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {198},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303482},
Abstract = {Hydraulic fracturing is a widely used well-stimulation
technique to enhance the productivity of gas or petroleum in
the wells of tight oil and tight gas since it was first
introduced in 1947. In the earth formations of low porosity
and low permeability, the fracture is commonly induced
hydraulically to increase the exposed area of the producing
formation, allowing more hydrocarbon to flow into the
wellbore, and ultimately improving the production economics.
Thus, it is important to obtain the information about
fracture, including length, width, thickness and
orientation.},
Doi = {10.1109/USNC-URSI.2015.7303482},
Key = {fds321747}
}
@article{fds321745,
Author = {Mao, Z and Liu, L and Zhang, J and Liu, N and Liu, QH},
Title = {Electroporation control of complex cell system by varying
pulse voltage and duration},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Rf and Wireless Technologies for Biomedical and Healthcare
Applications, Imws Bio 2015 Proceedings},
Pages = {165-166},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479985432},
url = {http://dx.doi.org/10.1109/IMWS-BIO.2015.7303830},
Abstract = {Electroporation is a common but efficient method for cell
therapy. Pulses of duration ranging from microsecond to
nanosecond with specific voltage have been studied in recent
20 years. Since electric field is also an important factor
for effects on cell pore formation, we apply 100 ns and 10
ns pulses by varying their voltage acting on the complex
cell system. Prediction of electroporation effects is
obtained and guidance can be offered for experiments.
Furthermore, a special short duration pulse may be designed
to cause organelle tp electroporate.},
Doi = {10.1109/IMWS-BIO.2015.7303830},
Key = {fds321745}
}
@article{fds321744,
Author = {Liu, L and Mao, Z and Zhang, J and Liu, N and Liu, QH},
Title = {The influence of nanosecond pulsed field on a double-shelled
ellipsoid cell},
Journal = {2015 Ieee Mtt S International Microwave Workshop Series on
Rf and Wireless Technologies for Biomedical and Healthcare
Applications, Imws Bio 2015 Proceedings},
Pages = {163-164},
Year = {2015},
Month = {October},
ISBN = {9781479985432},
url = {http://dx.doi.org/10.1109/IMWS-BIO.2015.7303829},
Abstract = {When cells are exposed to very short and high strength
electric pulses, they will deform from spherical shape to
ellipsoidal shape, and these effects may occur on cellular
and organelles. Because of their potential clinical
applications, selective effects on organelles are of
particular interest. In this work, we use the finite element
method to investigate the influence of nanosecond pulsed
field on a double-shell ellipsoidal cell. The corresponding
transmembrane potential (TMP) and pore density are examined
to analyze the response of cells to such a short pulse
field. Our active model demonstrates that for the prolate
double-shelled cell, the TMP and pore density of the nuclear
membrane exceed that on the cell membrane. Our calculation
may be useful to guide electroporation experiments.},
Doi = {10.1109/IMWS-BIO.2015.7303829},
Key = {fds321744}
}
@article{fds321743,
Author = {Ren, Q and Zhan, Q and Liu, QH},
Title = {Discontinuous Galerkin spectral elemen/finite element time
domain (DGSE/FETD) method for anisotropic
medium},
Journal = {2015 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2015 Proceedings},
Pages = {81},
Publisher = {IEEE},
Year = {2015},
Month = {October},
ISBN = {9781479978175},
url = {http://dx.doi.org/10.1109/USNC-URSI.2015.7303365},
Abstract = {Time domain methods, such as spectral element time domain
(SETD) and finite element time domain (FETD) methods have
potentials in solving transient and nonlinear problems. SETD
method is suitable for the space with only coarse
structures. Because large elements in SETD will not bring
large geometric error. However, the high-order hexahedrons
in SETD method can achieve good accuracy with low spatial
sampling density. While tetrahedrons in finite element time
domain (FETD) method can seize the detailed geometry
information of the fine structures in the computational
region, but the low-order elements in FETD is not high
efficient as SETD in DoFs. Thus a hybrid of them via
discontinuous Galerkin (DG) method can inherit the
advantages of both methods. Riemann Solver is used to deal
with the energy communication between adjacent
subdomains.},
Doi = {10.1109/USNC-URSI.2015.7303365},
Key = {fds321743}
}
@article{fds283385,
Author = {Liu, N and Cai, G and Zhu, C and Tang, Y and Liu, QH},
Title = {The Mixed Spectral-Element Method for Anisotropic, Lossy,
and Open Waveguides},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {63},
Number = {10},
Pages = {3094-3102},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {October},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2015.2472416},
Abstract = {The higher order mixed spectral-element method (SEM) is
proposed for the analysis of anisotropic, lossy, and open
waveguides. The new variational formulation incorporating
Gauss' law into the vectorial wave equation is completely
free of spurious modes. It utilizes the edge-based
curl-conforming Gauss-Lobatto-Legendre (GLL) polynomials to
approximate the tangential vector of the electric field and
the nodal-based scalar GLL basis functions to discretize its
longitudinal component to obtain the highly accurate
solution. By employing the mass-lumping technique, only a
smaller generalized eigenvalue problem needs to be solved.
Several numerical examples are given to verify that the
mixed SEM is free of any spurious eigenmode and has spectral
accuracy with the propagation constant.},
Doi = {10.1109/TMTT.2015.2472416},
Key = {fds283385}
}
@article{fds283400,
Author = {Yang, H and Li, T and Li, N and He, Z and Liu, QH},
Title = {Efficient Near-Field Imaging for Single-Borehole Radar With
Widely Separated Transceivers},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {53},
Number = {10},
Pages = {5327-5337},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {October},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2015.2421478},
Abstract = {In this paper, the formulation of Stolt migration is
modified for impulse borehole radar near-field imaging in
the subsurface scenarios where the transceiver is widely
separated with respect to the detection range. The proposed
approach consists of the following aspects. First, the
locations of the transmitter and receiver in the survey are
regarded as independent sample dimensions, and the original
sample set is converted to an enlarged virtual sample set.
The frequency-wavenumber spectrum (FWS) of the virtual
sample set is available via multidimensional fast Fourier
transform (FFT). Then, the relation between the angular
frequency and wavenumbers of the transmitter and receiver is
derived in the frame of the virtual sample set, which
provides the basis for the interpolation in angular
frequency and weighting process of FWS. By applying
multidimensional inverse FFT (IFFT) to the interpolated and
weighted FWS of the virtual sample set, the energy of target
responses will focus in some profile of the IFFT result, the
position of which is related with the separation between the
transmitter and receiver. Finally, the desired target space
can be extracted from the IFFT result. The improved Stolt
migration technique is compared with the conventional Stolt
migration algorithm, back-projection method, and Kirchhoff
migration algorithm on synthetic data and validated by
single-borehole radar experiment in the subsurface scenario.
The results show that the developed Stolt migration is
superior to the conventional methods in cross-range
resolution, computational cost, and the ability to
reconstruct locations and shapes of targets.},
Doi = {10.1109/TGRS.2015.2421478},
Key = {fds283400}
}
@article{fds314355,
Author = {Zhang, Y and Zhao, Z and Nie, Z and Liu, QH},
Title = {Optimization of graded materials for broadband radome wall
with DRR control using a hybrid method},
Journal = {Progress in Electromagnetics Research M},
Volume = {43},
Pages = {193-201},
Publisher = {EMW Publishing},
Year = {2015},
Month = {September},
ISSN = {1937-8726},
url = {http://dx.doi.org/10.2528/PIERM15081004},
Abstract = {A graded material structure is optimized for broadband
radome application by using hybrid method in this paper. In
the optimization, dynamic range ratio (DRR) of real
permittivity and loss of material are taken into
considerations. By using an analytical function, the
optimization problem with the DRR constraint is converted to
an unconstrained problem. The proposed hybrid method is a
combination of trust region method (TRM) and genetic
algorithm (GA). Firstly (TRM) is applied to optimize the
dielectric constant distribution. Then the result of TRM is
used as initial value of GA. GA is employed to improve the
global property of the results provided by TRM. Because TRM
has the advantage of fast searching speed and GA has the
advantage of global property, the hybrid method has the
feature of fast convergence speed. And the jitter property
of GA permittivity distribution is moderated. The
effectiveness of the hybrid is validated through the designs
of two broadband radome walls. The minimum power
transmission efficiency is 81.9% ranging from 1 GHz to 18GHz
for normal incidence.},
Doi = {10.2528/PIERM15081004},
Key = {fds314355}
}
@article{fds321748,
Author = {Liu, N and Jiang, W and Huang, Y and Liu, QH},
Title = {The mixed spectral element method: A novel approach to
remove zero spurious modes in electromagnetics},
Journal = {2015 Computational Electromagnetics International Workshop,
Cem 2015},
Pages = {56-57},
Publisher = {IEEE},
Year = {2015},
Month = {September},
ISBN = {9781467371971},
url = {http://dx.doi.org/10.1109/CEM.2015.7237438},
Abstract = {In this paper, we propose a novel mixed spectral element
method (mixed SEM) to remove such zero spurious modes and
significantly improve the numerical solutions of the Maxwell
eigenvalue problem. We will demonstrate this mixed SEM with
the applications in waveguides and cavities. In order to
suppress the zero spurious modes, the divergence-free
condition (i.e., Gauss' law) must be enforced in the
spectral element. The novel high-order mixed SEM is proposed
for the analysis of anisotropic, lossy, and open waveguides
and cavities. It utilizes the edge-based curl-conforming
Gauss-Lobatto-Legendre (GLL) polynomials to approximate the
tangential vector of the electric field; and for waveguide
problems, it uses the nodal-based scalar GLL basis functions
to discretize its longitudinal component to obtain the
highly accurate simulations.},
Doi = {10.1109/CEM.2015.7237438},
Key = {fds321748}
}
@article{fds283393,
Author = {Liu, Y and Chen, S and Ren, Y and Cheng, J and Liu, QH},
Title = {A broadband proximity-coupled dual-polarized microstrip
antenna with L-shape backed cavity for X-band
applications},
Journal = {Aeu International Journal of Electronics and
Communications},
Volume = {69},
Number = {9},
Pages = {1226-1232},
Publisher = {Elsevier BV},
Year = {2015},
Month = {September},
ISSN = {1434-8411},
url = {http://dx.doi.org/10.1016/j.aeue.2015.05.001},
Abstract = {A broadband proximity-coupled dual-polarized microstrip
antenna with a L-shape backed cavity is presented. The
L-shape cavity backed ground plane is used to enhance the
feeding coupling and thus to broaden the bandwidth of this
antenna. The parameter study is done in detail to show the
guideline of designing this antenna. A prototype antenna
with optimized parameters is designed and fabricated.
Simulation and measurement results show that the proposed
design achieves S11 ≤ -10 dB bandwidth of more than 30%
(8.2-11.4 GHz) and the port isolation is larger than 20 dB
over that band. This antenna has a relatively simple
structure, and can be directly mounted on the metal body
surface in application.},
Doi = {10.1016/j.aeue.2015.05.001},
Key = {fds283393}
}
@article{fds283399,
Author = {Zheng, J and Su, T and Zhu, W and Zhang, L and Liu, Z and Liu,
QH},
Title = {ISAR Imaging of Nonuniformly Rotating Target Based on a Fast
Parameter Estimation Algorithm of Cubic Phase
Signal},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {53},
Number = {9},
Pages = {4727-4740},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {September},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2015.2408350},
Abstract = {In inverse synthetic aperture radar (ISAR) imaging of
nonuniformly rotating targets, such as highly maneuvering
airplanes and ships fluctuating with oceanic waves, azimuth
echoes have to be modeled as cubic phase signals (CPSs)
after the range migration compensation and the
translational-induced phase error correction. For the CPS
model, the chirp rate and the quadratic chirp rate, which
deteriorate the azimuth focusing quality due to the Doppler
frequency shift, need to be estimated with a parameter
estimation algorithm. In this paper, by employing the
proposed generalized scaled Fourier transform (GSCFT) and
the nonuniform fast Fourier transform (NUFFT), a fast
parameter estimation algorithm is presented and utilized in
the ISAR imaging of the nonuniformly rotating target.
Compared to the scaled Fourier transform-based algorithm,
advantages of the fast parameter estimation algorithm
include the following: 1) the computational cost is lower
due to the utilization of the NUFFT, and 2) the GSCFT has a
wider applicability in ISAR imaging applications. The CPS
model and the algorithm implementation are verified with the
real radar data of a ship target. In addition, the
cross-term, which plays an important role in correlation
algorithms, is analyzed for the fast parameter estimation
algorithm. Through simulations of the synthetic data and the
real radar data, we verify the effectiveness of the fast
parameter estimation algorithm and the corresponding ISAR
imaging algorithm.},
Doi = {10.1109/TGRS.2015.2408350},
Key = {fds283399}
}
@article{fds321749,
Author = {Li, W and Chen, Y and Cai, G and Liu, QH},
Title = {A plasmonic sensor based on nanopatch photonic crystal slab
with simultaneously high sensing performance and clear
registration},
Journal = {Icocn 2015 14th International Conference on Optical
Communications and Networks, Proceedings},
Publisher = {IEEE},
Year = {2015},
Month = {August},
ISBN = {9781467373739},
url = {http://dx.doi.org/10.1109/ICOCN.2015.7203627},
Abstract = {A plasmonic sensor based on nanopatch photonic crystal slab
was proposed. The sizes of the nanopatch was optimized. With
shallow etched and small size of the nanopatch, the sensor
achieves simultaneously a high sensing performance of
FOM=171.6 RIU-1 and a clear registration of FH/FWHM=0.261
for the lattice constant of P=750. The results of P=1000 and
P=1250 are also presented.},
Doi = {10.1109/ICOCN.2015.7203627},
Key = {fds321749}
}
@article{fds283390,
Author = {Zheng, J and Su, T and Liao, G and Liu, H and Liu, Z and Liu,
QH},
Title = {ISAR Imaging for Fluctuating Ships Based on a Fast Bilinear
Parameter Estimation Algorithm},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {8},
Number = {8},
Pages = {3954-3966},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {August},
ISSN = {1939-1404},
url = {http://dx.doi.org/10.1109/JSTARS.2015.2440911},
Abstract = {For inverse synthetic aperture radar (ISAR) imaging of ships
fluctuating with oceanic waves, azimuth echoes of a range
cell have to be modeled as cubic phase signals (CPSs) after
the range alignment and the phase adjustment. In ISAR
imaging based on the CPS model, the chirp rate and the
quadratic chirp rate are identified as causes of the target
image defocus and need to be estimated with an effective
algorithm. In this paper, a fast bilinear parameter
estimation algorithm is proposed and applied in ISAR imaging
for fluctuating ships by employing the cubic phase bilinear
function, the nonuniform fast Fourier transform (NUFFT), and
the parameter space switching method. Compared to two
existing representative parameter estimation algorithms for
the CPS, the advantages of this proposed estimation
algorithm are: 1) the computational cost is lower due to the
NUFFT and the parameter space switching method and 2) the
bilinearity and the energy accumulation operation guarantee
a higher anti-noise performance and a better suppression on
cross-terms. Through simulations on synthetic models and the
real radar data, we verify the effectiveness of this fast
bilinear parameter estimation algorithm and the
corresponding ISAR imaging algorithm.},
Doi = {10.1109/JSTARS.2015.2440911},
Key = {fds283390}
}
@article{fds283391,
Author = {Dai, J and Liu, QH},
Title = {Efficient Computation of Electromagnetic Waves in
Anisotropic Orthogonal-Plano-Cylindrically Layered Media
Using the Improved Numerical Mode Matching (NMM)
Method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {8},
Pages = {3569-3578},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {August},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2015.2438329},
Abstract = {An orthogonal-plano-cylindrically layered (OPCL) medium
consists of materials stratified planarly and layered
concentrically in the orthogonal directions. The numerical
mode matching (NMM) method has previously been shown to be a
fast and robust semianalytical solver to investigate the
propagation of electromagnetic (EM) waves in such a complex
but isotropic or transversely isotropic medium. In this
paper, several important improvements have been made to
extend applications of this efficient solver to the
anisotropic OCPL medium. The formulas for anisotropic media
with three different diagonal elements in the cylindrical
coordinate system are deduced to expand its application. The
perfectly matched layer (PML) is incorporated along the
radial direction as an absorbing boundary condition (ABC) to
make the NMM method more accurate and efficient for
unbounded low conductivity media and applicable to lossless
media. We manipulate the weak form of Maxwell's equations
and impose the correct boundary conditions at the
cylindrical axis to solve the singularity problem. Finally,
we also offer formulas for computing EM fields excited by a
magnetic dipole located at any position with an arbitrary
orientation. Numerical results have demonstrated the
efficiency and accuracy of this method.},
Doi = {10.1109/TAP.2015.2438329},
Key = {fds283391}
}
@article{fds283384,
Author = {Song, Z and Zhu, J and Zhu, C and Yu, Z and Liu, Q},
Title = {Broadband cross polarization converter with unity efficiency
for terahertz waves based on anisotropic dielectric
meta-reflectarrays},
Journal = {Materials Letters},
Volume = {159},
Pages = {269-272},
Publisher = {Elsevier BV},
Year = {2015},
Month = {July},
ISSN = {0167-577X},
url = {http://dx.doi.org/10.1016/j.matlet.2015.07.024},
Abstract = {We show that the linear polarization state of
electromagnetic waves at terahertz frequencies can be
perfectly rotated to its orthogonal direction by an
alternative design of anisotropic dielectric
meta-reflectarrays. Numerical results demonstrate that the
reflection coefficient converting to cross polarization
after reflection can be as high as ∼100% from 0.75 THz to
1.0 THz. The designed system does suffer little energy loss
due to the absence of the metallic metamaterial unit cells
and the absorptive dielectric.},
Doi = {10.1016/j.matlet.2015.07.024},
Key = {fds283384}
}
@article{fds283392,
Author = {Zhang, L and Song, Z and Liu, QH},
Title = {Optical cross-polarization converter with an octave
bandwidth based on anisotropic plasmonic
meta-surfaces},
Journal = {Epl (Europhysics Letters)},
Volume = {111},
Number = {2},
Pages = {27001-27001},
Publisher = {IOP Publishing},
Year = {2015},
Month = {July},
ISSN = {0295-5075},
url = {http://dx.doi.org/10.1209/0295-5075/111/27001},
Abstract = {We show that the linear polarization state of
electromagnetic waves can be efficiently rotated to its
orthogonal direction by an alternative design of anisotropic
plasmonic meta-surfaces. Numerical results demonstrate that
the reflection coefficient converting to cross-polarization
after reflection is larger than 71% within an octave
frequency band from ∼232THz to ∼490THz. The designed
system is much thinner than conventional geometric-optics
devices, and takes favorable advantage of little energy
loss.},
Doi = {10.1209/0295-5075/111/27001},
Key = {fds283392}
}
@article{fds283379,
Author = {Li, N and Cui, G and Yang, H and Kong, L and Liu, QH},
Title = {Knowledge-aided Bayesian detection for MIMO radar in
compound-Gaussian clutter with inverse Gamma
texture},
Journal = {Ieee National Radar Conference Proceedings},
Volume = {2015-June},
Number = {June},
Pages = {777-782},
Publisher = {IEEE},
Year = {2015},
Month = {June},
ISBN = {9781479982325},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2015.7131101},
Abstract = {In this paper, we consider the adaptive detection with
multiple-input multiple-output (MIMO) radar in
compound-Gaussian clutter. The covariance matrices of the
primary and the secondary data share a common structure but
different power levels (textures). A Bayesian framework is
exploited where both the textures and the structure are
assumed to be random. Precisely, the textures follow inverse
Gamma distribution and the structure is drawn from an
inverse complex Wishart distribution. In this framework, the
generalized likelihood ratio test (GLRT) is derived.
Finally, we evaluate the capabilities of the proposed
detector against compound-Gaussian clutter as well as their
superiority with respect to some existing
techniques.},
Doi = {10.1109/RADAR.2015.7131101},
Key = {fds283379}
}
@article{fds283382,
Author = {Liao, Y and Xing, M and Bao, Z and Liu, QH},
Title = {Analysis on parameters and imaging algorithm of squint
circular trace scanning SAR},
Journal = {Ieee National Radar Conference Proceedings},
Volume = {2015-June},
Number = {June},
Pages = {151-155},
Publisher = {IEEE},
Year = {2015},
Month = {June},
ISBN = {9781479982325},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2015.7130987},
Abstract = {The squint circular trace scanning synthetic aperture radar
(squint CTSSAR) provides a practical option to realize fast
large area synthetic aperture radar (SAR) imaging. However,
its squint angle and unique flight trajectory result in its
difference from other SAR imaging modes. This paper
establishes the squint CTSSAR geometry model, and bases on
which analyzes the related parameter characteristics,
revealing the universality of the squint CTSSAR imaging
mode. In addition, the range order accuracy is analyzed and
an effective imaging algorithm is provided. In the end, the
corresponding simulated experiments validate the feasibility
and the effectiveness of the proposed imaging
method.},
Doi = {10.1109/RADAR.2015.7130987},
Key = {fds283382}
}
@article{fds283386,
Author = {Yang, H and Li, N and Li, T and Zhong, H and He, Z and Liu,
QH},
Title = {An improved near-field imaging algorithm based on Stolt
migration for single borehole radar with widely separated
transceiver},
Journal = {Ieee National Radar Conference Proceedings},
Volume = {2015-June},
Number = {June},
Pages = {444-449},
Publisher = {IEEE},
Year = {2015},
Month = {June},
ISBN = {9781479982325},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2015.7131040},
Abstract = {In this paper, the Stolt migration algorithm is modified for
impulse borehole radar in near-field imaging where the
transceiver is widely separated with respect to the
detection range. The original sample set is converted to a
multidimensional virtual sample set. The relation between
angular frequency and wavenumbers of transmitter and
receiver is derived in the frame of virtual sample set,
which provides the basis for the interpolation in angular
frequency. By applying multidimensional inverse fast Fourier
transform (IFFT) to the interpolated frequency-wavenumber
spectrum of the virtual sample set, the energy of target
responses will focus in some profile of the IFFT result,
which can be extracted according to the separation between
the transmitter and receiver. The proposed method is
compared with the conventional Stolt migration algorithm,
back projection method, and Kirchhoff migration algorithm on
synthetic data. The results show that the developed Stolt
migration is superior to the conventional methods in
cross-range resolution, computational cost, and the ability
to reconstruct locations and shapes of targets.},
Doi = {10.1109/RADAR.2015.7131040},
Key = {fds283386}
}
@article{fds283387,
Author = {Li, N and Cui, G and Yang, H and Kong, L and Liu, QH},
Title = {Adaptive detection based on multiple a-priori spectral
models for MIMO radar in compound-Gaussian
clutter},
Journal = {Ieee National Radar Conference Proceedings},
Volume = {2015-June},
Number = {June},
Pages = {870-875},
Publisher = {IEEE},
Year = {2015},
Month = {June},
ISBN = {9781479982325},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2015.7131117},
Abstract = {In this paper, we consider the adaptive detection with
multiple-input multiple-output (MIMO) radar in the presence
of compound-Gaussian clutter with a limited number of
secondary data set. We assume that multiple a-priori
spectral models for the clutter are available, and model the
actual clutter inverse covariance structure as a combination
of these available a-priori models. In this framework, a
sequential optimization algorithm is first presented to
estimate the unknown parameters. Then, an approximate
generalized likelihood ratio test (GLRT) is developed by
exploiting the obtained estimates. Finally, we evaluate the
capabilities of the proposed detector against
compound-Gaussian clutter as well as its superiority with
respect to some existing techniques with few secondary data
support.},
Doi = {10.1109/RADAR.2015.7131117},
Key = {fds283387}
}
@article{fds283396,
Author = {Yang, H and Li, N and Li, T and Zhong, H and He, Z and Liu,
QH},
Title = {A modified Stolt migration imaging algorithm for large
nonuniform single borehole radar surveys},
Journal = {Ieee National Radar Conference Proceedings},
Volume = {2015-June},
Number = {June},
Pages = {438-443},
Publisher = {IEEE},
Year = {2015},
Month = {June},
ISBN = {9781479982325},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2015.7131039},
Abstract = {In this paper, the formulation of Stolt migration is
modified for impulse borehole radar imaging in large
nonuniform subsurface scenarios. By applying the nonuniform
fast Fourier transform to the acquisition of
frequency-wavenumber spectrum, the efficiency of Stolt
migration for nonuniform surveys is improved. The selection
of approximation parameters is discussed to make a tradeoff
between approximation error and computational cost. The
improved Stolt migration technique is compared with
conventional back projection method and Kirchhoff migration
method on synthetic data and validated by single borehole
radar experiment in subsurface scenario. The results show
that the developed Stolt migration is superior to the
conventional methods in cross-range resolution,
computational cost, and the ability to reconstruct locations
and shapes of targets.},
Doi = {10.1109/RADAR.2015.7131039},
Key = {fds283396}
}
@article{fds283397,
Author = {Ren, Q and Tobon, LE and Sun, Q and Liu, QH},
Title = {A new 3-D nonspurious discontinuous galerkin spectral
element time-domain (DG-SETD) Method for Maxwell's
Equations},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {6},
Pages = {2585-2594},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {June},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2015.2417891},
Abstract = {A new discontinuous Galerkin spectral element time-domain
(DG-SETD) method for Maxwell's equations based on the field
variables \mathbf{E} and \mathbf{B} is proposed to analyze
three-dimensional (3-D) transient electromagnetic phenomena.
Compared to the previous SETD method based on the field
variables \mathbf{E} and \mathbf{H} (the \mathbf{EH}
scheme), in which different orders of interpolation
polynomials for electric and magnetic field intensities are
required, the newly proposed method can eliminate spurious
modes using basis functions with the same order
interpolation for electric field intensity and magnetic flux
density (the \mathbf{EB} scheme). Consequently, it can
reduce the number of unknowns and computation load. Domain
decomposition for the \mathbf{EB} scheme SETD method is
completed via the DG method. In addition, the \mathbf{EB}
scheme SETD method is extended to the well-posed time-domain
perfectly matched layer (PML) to truncate the computation
domain when solving open-region problems. The effectiveness
and advantages of the new DG-SETD method are validated by
eigenvalue analysis and numerical results.},
Doi = {10.1109/TAP.2015.2417891},
Key = {fds283397}
}
@article{fds321751,
Author = {Luo, M and Liu, QH},
Title = {Extraordinary enhancement of second harmonic generation in a
periodically patterned distributed Bragg
reflector},
Journal = {Journal of the Optical Society of America
B},
Volume = {32},
Number = {6},
Pages = {1193-1201},
Publisher = {The Optical Society},
Year = {2015},
Month = {June},
url = {http://dx.doi.org/10.1364/JOSAB.32.001193},
Abstract = {Extraordinary enhancement of second harmonic generation is
engineered in a three-dimensional air-bridge photonic
crystal slab with a multiple-layer dielectric structure by
the spectral element method. By exploiting the symmetry of
the multiple-layer system, the large matrix equation arising
in the spectral element method can be solved by using the
block Thomas algorithm to significantly improve the
efficiency of the solver. A 63-layer structure with a total
thickness less than 8 μm is designed to achieve large
enhancement of the second harmonic generation effect by
almost 10 orders of magnitude, with an output second
harmonic field power rate of more than 0.1% under a typical
laser incident field of 0.5 MV/m. In addition, the
sensitivity of the transmittance to the thickness of each
layer is investigated. The sensitivity result shows that at
the resonant frequency with large second harmonic
generation, the sensitivity to the thickness is large, so
the thickness precision is important to obtain large
enhancement for the second harmonic generation. The
application of this system to highly monochromatic light
sources is discussed.},
Doi = {10.1364/JOSAB.32.001193},
Key = {fds321751}
}
@article{fds283402,
Author = {You, P and Liu, Y and Huang, X and Zhang, L and Liu,
QH},
Title = {Efficient phase-only linear array synthesis including
coupling effect by GA-FFT based on least-square active
element pattern expansion method},
Journal = {Electronics Letters},
Volume = {51},
Number = {10},
Pages = {791-792},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2015},
Month = {May},
ISSN = {0013-5194},
url = {http://dx.doi.org/10.1049/el.2015.0431},
Abstract = {A new least-square active element pattern expansion
(LS-AEPE) method is presented. With the help of this method,
the array's pattern including the element mutual coupling
and platform effect can be efficiently calculated by the
fast Fourier transform (FFT). These techniques are then
combined with the genetic algorithm (GA) to optimise the
excitation phases for a 64-element linear array mounted on a
trapezoid metal plate.},
Doi = {10.1049/el.2015.0431},
Key = {fds283402}
}
@article{fds283398,
Author = {Huang, WF and Zhao, Z and Zhao, R and Wang, JY and Nie, Z and Liu,
QH},
Title = {GO/PO and PTD With Virtual Divergence Factor for Fast
Analysis of Scattering From Concave Complex
Targets},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {5},
Pages = {2170-2179},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {May},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2015.2405086},
Abstract = {Due to simplicity, hybridization of geometrical optics (GO)
and physical optics (PO) based on ray tracing has been
widely used for fast scattering analyses. However, when
targets of curved concavities are discretized by flat
facets, the loss of divergence factor (DF) will degrade the
simulation accuracy. To remedy this loss, a simple and
efficient factor, entitled virtual divergence factor (VDF),
is proposed to play the role of DF. To prove the validity of
VDF and simulate the scattering of concave complex targets,
a hybrid method of GO/PO and physical theory of diffraction
(PTD) is elucidated. With VDF correction, several typical
targets, including a S-shape cavity, are simulated by this
hybrid method. In comparison to multilevel fast multipole
algorithm (MLFMA) or measurements, the validaty of VDF is
fully demonstrated by good agreements and the excellent
performance relative to DF on canonical surfaces, where the
great efficiency and flexibility of this hybrid method are
also shown. Moreover, one interesting and important issue,
the dependance of field convergence on the maximum number of
ray reflections, is also investigated for the first
time.},
Doi = {10.1109/TAP.2015.2405086},
Key = {fds283398}
}
@article{fds283407,
Author = {Wang, J and Zhao, Z and Song, J and Chen, G and Nie, Z and Liu,
Q-H},
Title = {Reducing the effects of acoustic heterogeneity with an
iterative reconstruction method from experimental data in
microwave induced thermoacoustic tomography.},
Journal = {Medical Physics},
Volume = {42},
Number = {5},
Pages = {2103-2112},
Year = {2015},
Month = {May},
ISSN = {0094-2405},
url = {http://dx.doi.org/10.1118/1.4916660},
Abstract = {<h4>Purpose</h4>An iterative reconstruction method has been
previously reported by the authors of this paper. However,
the iterative reconstruction method was demonstrated by
solely using the numerical simulations. It is essential to
apply the iterative reconstruction method to practice
conditions. The objective of this work is to validate the
capability of the iterative reconstruction method for
reducing the effects of acoustic heterogeneity with the
experimental data in microwave induced thermoacoustic
tomography.<h4>Methods</h4>Most existing reconstruction
methods need to combine the ultrasonic measurement
technology to quantitatively measure the velocity
distribution of heterogeneity, which increases the system
complexity. Different to existing reconstruction methods,
the iterative reconstruction method combines time reversal
mirror technique, fast marching method, and simultaneous
algebraic reconstruction technique to iteratively estimate
the velocity distribution of heterogeneous tissue by solely
using the measured data. Then, the estimated velocity
distribution is used subsequently to reconstruct the highly
accurate image of microwave absorption distribution.
Experiments that a target placed in an acoustic
heterogeneous environment are performed to validate the
iterative reconstruction method.<h4>Results</h4>By using the
estimated velocity distribution, the target in an acoustic
heterogeneous environment can be reconstructed with better
shape and higher image contrast than targets that are
reconstructed with a homogeneous velocity
distribution.<h4>Conclusions</h4>The distortions caused by
the acoustic heterogeneity can be efficiently corrected by
utilizing the velocity distribution estimated by the
iterative reconstruction method. The advantage of the
iterative reconstruction method over the existing correction
methods is that it is successful in improving the quality of
the image of microwave absorption distribution without
increasing the system complexity.},
Doi = {10.1118/1.4916660},
Key = {fds283407}
}
@article{fds283401,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {A Printed Unidirectional Antenna With Improved Upper
Band-Edge Selectivity Using a Parasitic Loop},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {4},
Pages = {1832-1837},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {April},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2015.2392112},
Abstract = {In this communication, a printed unidirectional antenna with
improved upper band-edge selectivity is proposed to realize
bandpass filtering gain performance. This antenna consists
of a printed rectangular loop with two gaps: 1) a parasitic
strip and 2) a parasitic loop. The rectangular loop provides
good lower band-edge selectivity and the parasitic strip
decides the location of upper band-edge selectivity. The
parasitic loop, which acts as a director, is used to improve
the capacity of upper band-edge selectivity. In addition,
the passband bandwidth controllability of the antenna has
also been explored. To demonstrate the effectiveness of this
design, an antenna prototype is fabricated and tested.
Experimental results verified the effectiveness of the
proposed design. Measured results show that the fabricated
antenna provides a 56.6% passband bandwidth, ranging from
2.18 to 3.9 GHz. Good bandpass filtering gain performance
with a flat passband gain better than 4.4 dBi is achieved.
Stable unidirectional radiation patterns with nearly
identical $E$- and $H$-plane patterns in the operating
bandwidth are also achieved. The measured front-to-back
ratio is better than 10 dB.},
Doi = {10.1109/TAP.2015.2392112},
Key = {fds283401}
}
@article{fds283404,
Author = {Liu, Y and Zhang, L and Zhu, C and Liu, QH},
Title = {Synthesis of nonuniformly spaced linear arrays with
frequency-invariant patterns by the generalized matrix
pencil methods},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {4},
Pages = {1614-1625},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {April},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2015.2394497},
Abstract = {This work extends the matrix pencil method (MPM)-based
synthesis technique to the case of nonuniformly spaced
linear arrays with wideband frequency-invariant (FI)
patterns. A new sampling strategy is proposed to obtain
multiple pattern data of different frequencies having the
same poles that correspond to the FI element positions. The
obtained multiple pattern sequences have the same shape for
the FI pattern requirement, but with different lengths. The
generalized MPM (GMPM) and its forward-backward version
(GFBMPM) are developed to estimate the best common element
positions for different frequencies, which can significantly
reduce the number of elements required for the specified
wideband pattern shape. The element excitations are solved
by the regularized least-square (LS) method at each
frequency. Then, an efficient method by utilizing the FFT is
presented to obtain real-coefficient finite-impulse-response
(FIR) filters for implementing the frequency-varying
excitations. A set of numerical examples for the FI
synthesis of pencil-beams, shaped patterns, scannable
patterns, and Taylor patterns with low SLLs are presented to
validate the effectiveness and advantages of the proposed
methods. The element saving is about 11.2%-49.4% for usual
cases.},
Doi = {10.1109/TAP.2015.2394497},
Key = {fds283404}
}
@article{fds283417,
Author = {Wu, J and Zhao, Z and Liu, QH},
Title = {A novel vivaldi antenna with extended ground plane stubs for
ultrawideband applications},
Journal = {Microwave and Optical Technology Letters},
Volume = {57},
Number = {4},
Pages = {983-987},
Publisher = {WILEY},
Year = {2015},
Month = {April},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.28955},
Abstract = {In this letter, a compact printed Vivaldi antenna with two
symmetrical extended ground plane stubs is presented. By
extending the stubs from the ground plane, the low-end
bandwidth limitation of the antenna is extended to low
frequencies and then the bandwidth is enlarged. To validate
the proposed design, an antenna prototype is fabricated and
tested. The measured results confirm that the modification
presented in this letter is very effective without changing
the overall dimensions of the antenna. The measured
impedance bandwidth defined by S11<-10 dB is from 2.45 to
15.2 GHz with a ratio of about 6.2:1. The measured gain is
better than 4.2 dBi within the operating frequency band. In
addition, a nearly constant group time delay is also
achieved across the band of 2.4-16 GHz.},
Doi = {10.1002/mop.28955},
Key = {fds283417}
}
@article{fds283427,
Author = {Li, Z and Wang, J and Liu, QH},
Title = {Frequency-domain backprojection algorithm for synthetic
aperture radar imaging},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {12},
Number = {4},
Pages = {905-909},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {April},
ISSN = {1545-598X},
url = {http://dx.doi.org/10.1109/LGRS.2014.2366156},
Abstract = {A new frequency-domain backprojection method for processing
synthetic aperture radar (SAR) data is presented. It forms
SAR images by backprojecting the spectrum of the radar echo
into the image wavenumber domain and is capable of fully
correcting wavefront curvature and handling a general
aperture geometry. From each reconstructed spectral pixel,
information about the entire scene can be obtained, allowing
the formation of interim lower resolution images during the
processing. In addition, the method allows for an arbitrary
sampling of the image spectrum. It forms SAR images by
backprojecting the spectrum of the radar echo into the image
wavenumber domain. Processing of simulated and experimental
ultrawideband/widebeam SAR raw data demonstrates the
efficacy of this new method.},
Doi = {10.1109/LGRS.2014.2366156},
Key = {fds283427}
}
@article{fds283408,
Author = {Feng, N and Yue, Y and Zhu, C and Wan, L and Liu, QH},
Title = {Second-order PML: Optimal choice of nth-order PML for
truncating FDTD domains},
Journal = {Journal of Computational Physics},
Volume = {285},
Pages = {71-83},
Publisher = {Elsevier BV},
Year = {2015},
Month = {March},
ISSN = {0021-9991},
url = {http://dx.doi.org/10.1016/j.jcp.2015.01.015},
Abstract = {The nth-order PMLs based on the unsplit-field formulations
and the Z-transform methods are proposed to truncate the
finite-difference time-domain (FDTD) domains, which will be
validated through numerical simulations whether the
higher-order PML with more than two poles, such as n=. 3,
will hold better absorption performance as compared with the
conventional, complex frequency shifted (CFS), second-order
perfectly matched layer (PMLs). The advantages and
disadvantages of different PMLs are demonstrated. It has
shown that the higher-order PMLs have the advantages of both
the conventional and the CFS PMLs in terms of absorption
performance, since the conventional PML is ineffective at
absorbing the evanescent waves and the CFS-PML is incapable
of absorbing low-frequency propagating waves. It is clearly
shown that the second-order PML is overall the optimal
choice for truncating arbitrary FDTD domains, since it not
only requires less computational time and memory, but holds
almost the same absorption performance as compared with the
third-order PML. Three numerical simulations have been
carried out in three-dimensional (3D) problems to confirm
the analysis.},
Doi = {10.1016/j.jcp.2015.01.015},
Key = {fds283408}
}
@article{fds283406,
Author = {Zheng, J and Su, T and Zhu, W and He, X and Liu, QH},
Title = {Radar High-Speed Target Detection Based on the Scaled
Inverse Fourier Transform},
Journal = {Ieee Journal of Selected Topics in Applied Earth
Observations and Remote Sensing},
Volume = {8},
Number = {3},
Pages = {1108-1119},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {March},
ISSN = {1939-1404},
url = {http://dx.doi.org/10.1109/JSTARS.2014.2368174},
Abstract = {In this paper, by employing the symmetric autocorrelation
function and the scaled inverse Fourier transform (SCIFT), a
coherent detection algorithm is proposed for high-speed
targets. This coherent detection algorithm is simple and can
be easily implemented by using complex multiplications, the
fast Fourier transform (FFT) and the inverse FFT (IFFT).
Compared to the Hough transform and the keystone transform,
this coherent detection algorithm can detect high-speed
targets without the brute-force searching of unknown motion
parameters and achieve a good balance between the
computational cost and the antinoise performance. Through
simulations and analyses for synthetic models and the real
data, we verify the effectiveness of the proposed coherent
detection algorithm.},
Doi = {10.1109/JSTARS.2014.2368174},
Key = {fds283406}
}
@article{fds283413,
Author = {Li, N and Cui, G and Kong, L and Liu, QH},
Title = {Moving target detection for polarimetric multipleinput
multiple-output radar in Gaussian clutter},
Journal = {Iet Radar, Sonar and Navigation},
Volume = {9},
Number = {3},
Pages = {285-298},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2015},
Month = {March},
ISSN = {1751-8784},
url = {http://dx.doi.org/10.1049/iet-rsn.2014.0157},
Abstract = {This study deals with the problem of moving target detection
(MTD) for polarimetric multiple-input multiple-output (MIMO)
radar in the presence of Gaussian clutter. The authors
extend the framework for MTD with MIMO radar to a generic
number polarisation channels case. Within the polarimetric
framework, the new generalised likelihood ratio test for
moving target is first proposed. Then, the target velocity
estimation problem is investigated. The maximum-likelihood
(ML) estimator for target velocity is developed, and the
corresponding Cramer-Rao bound is derived which serves as a
benchmark of the estimation performance. Next, the adaptive
version of the new polarimetric detector is considered. The
covariance matrix is estimated using the sample covariance
matrix and the model-based strategies based on the secondary
data. Finally, several numerical simulations of the proposed
polarimetric detector and ML estimator with typical
parameters are obtained and discussed.},
Doi = {10.1049/iet-rsn.2014.0157},
Key = {fds283413}
}
@article{fds283414,
Author = {Feng, N and Yue, Y and Liu, QH},
Title = {Direct Z-Transform implementation of the CFS-PML based on
memory-minimized method},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {63},
Number = {3},
Pages = {877-882},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {March},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2015.2389218},
Abstract = {Efficient and unsplit-field-based stretched coordinate
perfectly matched layer (PML) formulations with the complex
frequency-shifted (CFS) scheme that combine the
memory-minimized method (Tri-M) and the direct Z-transform
(DZT) method are proposed to truncate the finite-difference
time-domain lattices. The proposed algorithm takes advantage
of the minimized memory of the Tri-M method, the optimal
accuracy of the DZT method, and the capacity of the PML for
attenuating evanescent waves and reducing late-time
reflections. Three 3-D numerical simulations have been
carried out to validate the proposed formulations.},
Doi = {10.1109/TMTT.2015.2389218},
Key = {fds283414}
}
@article{fds283415,
Author = {Song, J and Zhao, Z and Wang, J and Zhu, X and Wu, J and Nie, Z and Liu,
Q-H},
Title = {Evaluation of contrast enhancement by carbon nanotubes for
microwave-induced thermoacoustic tomography.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {62},
Number = {3},
Pages = {930-938},
Year = {2015},
Month = {March},
ISSN = {0018-9294},
url = {http://dx.doi.org/10.1109/tbme.2014.2373397},
Abstract = {Microwave-induced thermoacoustic tomography (MITAT) is a
hybrid method which constructs images with ultrasound
spatial resolution while exploiting dielectric contrast at
microwave frequency. It has great potential in biomedical
imaging especially in early breast cancer detection. The
detection of early stage breast tumor in MITAT is challenged
by the moderate endogenous dielectric contrast between
malignant and healthy glandular tissues. In order to
overcome this limitation, the performance of using carbon
nanotubes (CNTs) as an imaging contrast enhancement agent is
evaluated. First, the influences in dielectric and acoustic
properties caused by CNTs are measured. Second, based on the
measurements and the published data, numerical breast
phantom is created and then used to explore the contrast
enhancing effect of CNTs for MITAT, by an integrated
simulation approach in both electromagnetic and acoustic
field. With an experimental MITAT system, the thermoacoustic
responses of tissue mimicking materials with different CNTs
concentrations are also quantitatively investigated.
Finally, the effectiveness of the contrast agent is also
validated experimentally by using a MITAT system. The
results show that the using of the dielectric contrast agent
can effectively enhance the contrast of the MITAT
image.},
Doi = {10.1109/tbme.2014.2373397},
Key = {fds283415}
}
@article{fds283470,
Author = {Li, Z and Wang, J and Wu, J and Liu, QH},
Title = {A fast radial scanned near-field 3-D SAR imaging system and
the reconstruction method},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {53},
Number = {3},
Pages = {1355-1363},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {March},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2014.2338396},
Abstract = {This paper presents a near-field 3-D synthetic aperture
radar (SAR) imaging system for which the 2-D aperture is
radially scanned. Compared to the current SAR imaging
systems, the proposed system has several advantages such as
quick data collection, full 360 ° inspection of target, and
simple image formation processing. However, in radial scan,
the samples do not fall on a Cartesian grid, which prevents
us from using the fast Fourier transform (FFT) to form SAR
image without calling for interpolation. In this paper, the
2-D nonuniform FFT (NUFFT) is used for dealing with the
problem. After 2-D NUFFT of the radial sampled data, the 3-D
reflectivity image can be efficiently reconstructed by using
the 3-D version of the range migration algorithm. The Stolt
mapping has been implemented implicitly by another 1-D NUFFT
to reduce the artifacts caused by the conventional
interpolation processing. In addition, to alleviate the data
sampling burden, a compressed 2-D slow-time sampling
strategy is also discussed. Finally, the proposed Rad-SAR
system and the imaging method are demonstrated using
near-field wideband simulation data.},
Doi = {10.1109/TGRS.2014.2338396},
Key = {fds283470}
}
@article{fds283418,
Author = {Xu, K and Zhang, Y and Fan, Y and Joines, WT and Liu,
QH},
Title = {Microstrip dual-mode bandpass filter design using
pie-section truncated semi-circle and quarter-circle
resonators},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {9},
Number = {3},
Pages = {224-229},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2015},
Month = {February},
ISSN = {1751-8725},
url = {http://dx.doi.org/10.1049/iet-map.2014.0170},
Abstract = {New dual-mode microstrip bandpass filters (BPFs) using
pie-section truncated semi-circle and/or quarter-circle
resonators are presented. The even-mode and odd-mode
frequency responses of these two resonators are
investigated. Compared to the four-parameter optimisation of
the conventional stub-loaded dual-mode resonator, only three
parameters need to be adjusted and optimised for the
proposed resonators. Based on these two novel resonators,
three BPF examples are designed, fabricated and tested. In
addition, the technique of source-load cross coupling to
improve performance of the filters is adopted. The good
agreement between simulated and measured results validates
the design concept.},
Doi = {10.1049/iet-map.2014.0170},
Key = {fds283418}
}
@article{fds283432,
Author = {Tobón, LE and Ren, Q and Liu, QH},
Title = {A new efficient 3D Discontinuous Galerkin Time Domain (DGTD)
method for large and multiscale electromagnetic
simulations},
Journal = {Journal of Computational Physics},
Volume = {283},
Pages = {374-387},
Publisher = {Elsevier BV},
Year = {2015},
Month = {February},
ISSN = {0021-9991},
url = {http://dx.doi.org/10.1016/j.jcp.2014.12.008},
Abstract = {A new Discontinuous Galerkin Time Domain (DGTD) method for
solving the 3D time dependent Maxwell's equations via the
electric field intensity E and magnetic flux density B
fields is proposed for the first time. It uses
curl-conforming and divergence-conforming basis functions
for E and B, respectively, with the same order of
interpolation. In this way, higher accuracy is achieved at
lower memory consumption than the conventional approach
based on the field variables E and H. The centered flux and
Riemann solver are both used to treat interfaces with
non-conforming meshes, and both explicit Runge-Kutta method
and implicit Crank-Nicholson method are implemented for time
integration. Numerical examples for realistic cases will be
presented to verify that the proposed method is a
non-spurious and efficient DGTD scheme.},
Doi = {10.1016/j.jcp.2014.12.008},
Key = {fds283432}
}
@article{fds283412,
Author = {Niu, J and Luo, M and Zhu, J and Liu, QH},
Title = {Enhanced plasmonic light absorption engineering of graphene:
simulation by boundary-integral spectral element
method.},
Journal = {Optics Express},
Volume = {23},
Number = {4},
Pages = {4539-4551},
Year = {2015},
Month = {February},
url = {http://dx.doi.org/10.1364/oe.23.004539},
Abstract = {Graphene's relatively poor absorption is an essential
obstacle for designing graphene-based photonic devices with
satisfying photo-responsivity. To enhance the tunable light
absorption of graphene, appropriate excitation of localized
surface plasmon resonance is considered as a promising
approach. In this work, the strategy of incorporating
periodic cuboid gold nanoparticle (NP) cluster arrays and
cylindrical gold NP arrays with Bragg reflectors into
graphene-based photodetectors are theoretically studied by
the boundary-integral spectral element method (BI-SEM). With
the BI-SEM, the models can be numerically analyzed with
excellent accuracy and efficiency. Numerical simulation
shows that the proposed structures can effectively engineer
the light absorption in graphene by tuning plasmon
resonance. In the spectra of 300 nm to 1000 nm, a maximum
light absorption of 67.54% is observed for the graphene
layer with optimal parameters of the photodetector
model.},
Doi = {10.1364/oe.23.004539},
Key = {fds283412}
}
@article{fds283420,
Author = {Zhu, C and Liu, QH and Liu, L and Liu, Y},
Title = {An accurate conformal fourier transform method for 3D
discontinuous functions},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {2},
Pages = {804-809},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {February},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2014.2378315},
Abstract = {Fourier transform of discontinuous functions are often
encountered in computational electromagnetics and other
areas. In this work, a highly accurate, fast conformal
Fourier transform (CFT) algorithm is proposed to evaluate
the finite Fourier transform of 3D discontinuous functions.
A curved tetrahedron mesh combined with curvilinear
coordinate transform, instead of the Cartesian grid, is
adopted to flexibly model an arbitrary shape of the
discontinuity boundary. This enables us to take full
advantages of high order interpolation and Gaussian
quadrature methods to achieve highly accurate Fourier
integration results with a low sampling density. The 3D
nonuniform fast Fourier transform (NUFFT) helps to keep the
complexity of the proposed algorithm to that similar to the
traditional 3D FFT algorithm. Therefore, the proposed CFT
algorithm can achieve order of magnitude higher accuracy
than 3D FFT with lower sampling density and similar
computation time. The convergence is proved and
verified.},
Doi = {10.1109/TAP.2014.2378315},
Key = {fds283420}
}
@article{fds283422,
Author = {Liu, N and Tobon, LE and Zhao, Y and Tang, Y and Liu,
QH},
Title = {Mixed spectral-element method for 3-D Maxwell's eigenvalue
problem},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {63},
Number = {2},
Pages = {317-325},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {February},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2014.2387839},
Abstract = {A high-order 3-D mixed spectral-element method (SEM) based
on Gauss-Lobatto-Legendre polynomials in the mixed
finite-element framework is proposed to remove the spurious
eigenmodes in the numerical solution of the vector Maxwell
eigenvalue problem with inhomogeneous, lossy isotropic, and
anisotropic media. In order to suppress all zero and nonzero
spurious modes that exist in the conventional finite-element
and higher order SEMs, the proposed method not only employs
the mixed-order curl-conforming vector basis functions for
the electric field intensity, but also includes the
divergence-free condition given by Gauss' law in a weak
form. Several numerical examples are given to verify that
the mixed SEM is free of any spurious eigenmodes and has
spectral accuracy with analytic eigenvectors.},
Doi = {10.1109/TMTT.2014.2387839},
Key = {fds283422}
}
@article{fds283423,
Author = {Xu, KD and Zhang, YH and Spiegel, RJ and Fan, Y and Joines, WT and Liu,
QH},
Title = {Design of a stub-loaded ring-resonator slot for antenna
applications},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {63},
Number = {2},
Pages = {517-524},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {February},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2014.2382646},
Abstract = {A T-shaped stub-loaded ring-resonator (SLRR) slot etched on
the ground plane or on the radiating patch has been designed
and analyzed for antenna applications. Compared with the
conventional ring slot, the two resonant frequencies of the
proposed SLRR-slot can be lowered, and can also be tunable
by varying the parameters of the four T-shaped stubs. To
validate the design concept, a tri-band printed antenna and
a dual band-notched ultra-wideband (UWB) antenna using the
SLRR-slot on the ground plane and radiating patch,
respectively, are presented. For the tri-band antenna, a
simple U-shaped slot etched on the microstrip feeding line
is used to excite a third upper-frequency band independently
without increasing the overall size of the antenna and
without affecting the lower two bands. The proposed tri-band
antenna has three frequency bands of 2.4, 3.5, and 5.8 GHz,
and the dual band-notched UWB antenna can guarantee a very
wide bandwidth from 3.0 to 12.0 GHz with dual undesired
bands successfully. The experimental results including
radiation patterns, peak gains and efficiencies of both
antennas are presented.},
Doi = {10.1109/TAP.2014.2382646},
Key = {fds283423}
}
@article{fds283411,
Author = {Cai, Y and Zhu, J and Liu, QH},
Title = {Tunable enhanced optical absorption of graphene using
plasmonic perfect absorbers},
Journal = {Applied Physics Letters},
Volume = {106},
Number = {4},
Pages = {043105-043105},
Publisher = {AIP Publishing},
Year = {2015},
Month = {January},
ISSN = {0003-6951},
url = {http://dx.doi.org/10.1063/1.4906996},
Abstract = {Enhancement and manipulation of light absorption in graphene
is a significant issue for applications of graphene-based
optoelectronic devices. In order to achieve this purpose in
the visible region, we demonstrate a design of a graphene
optical absorber inspired by metal-dielectric-metal
metamaterial for perfect absorption of electromagnetic
waves. The optical absorbance ratios of single and three
atomic layer graphene are enhanced up to 37.5% and 64.8%,
respectively. The graphene absorber shows
polarization-dependence and tolerates a wide range of
incident angles. Furthermore, the peak position and
bandwidth of graphene absorption spectra are tunable in a
wide wavelength range through a specific structural
configuration. These results imply that graphene in
combination with plasmonic perfect absorbers have a
promising potential for developing advanced nanophotonic
devices.},
Doi = {10.1063/1.4906996},
Key = {fds283411}
}
@article{fds283409,
Author = {Liu, N and Tobón, L and Tang, Y and Liu, QH},
Title = {Mixed spectral element method for 2D Maxwell's eigenvalue
problem},
Journal = {Communications in Computational Physics},
Volume = {17},
Number = {2},
Pages = {458-486},
Publisher = {Global Science Press},
Year = {2015},
Month = {January},
ISSN = {1815-2406},
url = {http://dx.doi.org/10.4208/cicp.230113.140814a},
Abstract = {It is well known that conventional edge elements in solving
vector Maxwell's eigenvalue equations by the finite element
method will lead to the presence of spurious zero
eigenvalues. This problem has been addressed for the first
order edge element by Kikuchi by the mixed element method.
Inspired by this approach, this paper describes a higher
order mixed spectral element method (mixed SEM) for the
computation of two-dimensional vector eigenvalue problem of
Maxwell's equations. It utilizes Gauss-Lobatto-Legendre
(GLL) polynomials as the basis functions in the
finite-element framework with a weak divergence condition.
It is shown that this method can suppress all spurious zero
and nonzero modes and has spectral accuracy. A rigorous
analysis of the convergence of the mixed SEM is presented,
based on the higher order edge element interpolation error
estimates, which fully confirms the robustness of our
method. Numerical results are given for homogeneous,
inhomogeneous, L-shape, coaxial and dual-inner-conductor
cavities to verify the merits of the proposed
method.},
Doi = {10.4208/cicp.230113.140814a},
Key = {fds283409}
}
@article{fds283378,
Author = {Rahmani, AR and Bryant, SL and Huh, C and Ahmadian, M and Zhang, W and Liu,
QH},
Title = {Characterizing reservoir heterogeneities using magnetic
nanoparticles},
Journal = {Society of Petroleum Engineers Spe Reservoir Simulation
Symposium 2015},
Volume = {1},
Pages = {74-102},
Year = {2015},
Month = {January},
ISBN = {9781510800618},
url = {http://dx.doi.org/10.2118/173195-ms},
Abstract = {As surface-coated superparamagnetic nanoparticles are
capable of flowing through micron-size pores across long
distances in a reservoir, with modest retention in rock,
they have novel use potential in subsurface applications.
These particles change the magnetic permeability of the
flooded region, and thus can be used to enhance images of
the subsurface and characterize hydrocarbon reservoirs. We
earlier demonstrated the feasibility of using magnetic
nanoparticles to track flood-front in waterflood and EOR
processes in a homogeneous reservoir. In this paper, we
model the propagation of a "ferrofluid" slug in a
heterogeneous reservoir and its response to a crosswell
magnetic tomography system. Specifically, we highlight the
magnetic response at a low frequency (10 Hz) to the magnetic
excitations generated by a vertical magnetic dipole source
positioned at the injection well. The "ferrofluid" alters
only the magnetic permeability of the domain occupied by the
fluid and is thus distinct from methods that rely on
contrasts in electrical conductivity. The flow behavior of
the magnetic nanoparticles is coupled with time-lapse
magnetic measurements through applying appropriate mixing
laws and effective medium theory. Fluid flow is computed
with a reservoir simulator; the electromagnetic response is
computed with an electromagnetic (EM) simulator developed at
Duke University for the overburden/reservoir/underburden
system. The approach to monitoring fluid movement within a
reservoir is built on established electromagnetic
conductivity monitoring technology. Here we investigate the
detectability of a contrast in magnetic permeabilities
between injected and resident fluids. At the low frequency
studied here, the induction effect is small, the casing
effect is manageable, the crosswell response originates
purely from the magnetic contrast in the formation, and
changes in fluid conductivities are irrelevant. This
approach thus offers a new and independent mechanism for
tracking flood fronts. Numerical simulations indicate that
the influence of areal and vertical reservoir permeability
heterogeneity on flood fronts can be detected. For areal
permeability heterogeneity, we use a five-spot reservoir
model (with injector in the center) and incorporate high-
and low-permeability ellipsoidal features with two
orientations. The most detectable heterogeneity is a low
permeability feature perpendicular to the streamlines. For
vertical heterogeneity, we devise a two-layer reservoir
model with single-well radial injection with a variable
thickness for the high-permeability layer and study the
evolution of time-lapse magnetic tomography maps. The
tomography maps are shown to be capable of detecting the
vertical heterogeneity in different stages of the flood.
This is particularly helpful for identifying thief zones. In
all the cases, the magnetic response is sensitive to the
pattern and distribution of streamlines; therefore,
permeability heterogeneity could be deduced from time-lapse
magnetic measurements. By adding magnetic nanoparticles into
the injection fluids for waterflood and EOR processes and
utilizing the established EM crosswell tomography technique,
we show the feasibility of inferring the major features of
reservoir heterogeneity, as well as of tracking the
injectant bank front, from the time-lapse magnetic
responses. This can substantially improve the management and
optimization of such floods.},
Doi = {10.2118/173195-ms},
Key = {fds283378}
}
@article{fds283403,
Author = {Li, N and Cui, G and Yang, H and Kong, L and Huo Liu and Q and Iommelli,
S},
Title = {Adaptive detection of moving target with MIMO radar in
heterogeneous environments based on Rao and Wald
tests},
Journal = {Signal Processing},
Volume = {114},
Pages = {198-208},
Publisher = {Elsevier BV},
Year = {2015},
Month = {January},
ISSN = {0165-1684},
url = {http://dx.doi.org/10.1016/j.sigpro.2015.02.019},
Abstract = {Abstract This paper deals with the adaptive detection of
moving targets for multiple-input multiple-output (MIMO)
radar in heterogeneous clutter environments. Two new
detectors based on Rao and Wald criteria are developed using
an ad hoc design procedure. Precisely, we first obtain the
Rao and Wald tests by assuming the known target velocity and
the known structure of the clutter. Then, we modify them by
performing a numerical optimization with respect to the
target velocity and replacing the clutter covariance matrix
with a proper estimate. With a limited number of secondary
data set, a class of covariance matrix estimators, defined
as the geometric barycenters of some basic covariance matrix
estimates obtained from the available secondary data set,
are proposed by exploiting the characteristic of the
positive-definite matrix space. Finally, numerical results
are presented to demonstrate the effectiveness of the
proposed detectors and covariance matrix
estimators.},
Doi = {10.1016/j.sigpro.2015.02.019},
Key = {fds283403}
}
@article{fds283410,
Author = {Wei, S and Zhuang, M and Zhou, J and Liu, QH},
Title = {A 2-D enlarged cell technique (ECT) for elastic wave
modelling on a curved free surface},
Journal = {Geophysical Journal International},
Volume = {201},
Number = {1},
Pages = {475-485},
Publisher = {Oxford University Press (OUP)},
Year = {2015},
Month = {January},
ISSN = {0956-540X},
url = {http://dx.doi.org/10.1093/gji/ggv039},
Abstract = {The conventional finite-difference time-domain (FDTD) method
for elastic waves suffers from the staircasing errorwhen
applied to model a curved free surface because of the
structured grid. This is similar to the situation for the
FDTD method in electromagnetics when it is applied to model
a curved perfect conductor surface, where the conformal FDTD
methods have been recently developed to avoid this error. In
this work a stable and second-order accurate 2-D FDTD method
for elastic wave modelling on a curved free surface is
presented based on the finite volume method and enlarged
cell technique (ECT). To achieve a sufficiently accurate
implementation, a finite volume scheme is applied to the
curved free surface to remove the staircasing error; in the
meantime, to achieve the same stability as the FDTD method
without reducing the time step increment, the ECT is
introduced to preserve the solution stability even for small
irregular cells. This method is verified by several 2-D
numerical examples. Results show that the method is
second-order accurate and stable at the Courant stability
limit for a regular FDTD grid.},
Doi = {10.1093/gji/ggv039},
Key = {fds283410}
}
@article{fds283416,
Author = {Tobon, LE and Ren, Q and Sun, Q and Chen, J and Liu,
QH},
Title = {New efficient implicit time integration method for DGTD
applied to sequential multidomain and multiscale
problems},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {151},
Pages = {1-8},
Publisher = {EMW Publishing},
Year = {2015},
Month = {January},
url = {http://dx.doi.org/10.2528/pier14112201},
Abstract = {The discontinuous Galerkin’s (DG) method is an efficient
technique for packaging problems. It divides an original
computational region into several subdomains, i.e., splits a
large linear system into several smaller and balanced
matrices. Once the spatial discretization is solved, an
optimal time integration method is necessary. For explicit
time stepping schemes, the smallest edge length in the
entire discretized domain determines the maximal time step
interval allowed by the stability criterion, thus they
require a large number of time steps for packaging problems.
Implicit time stepping schemes are unconditionally stable,
thus domains with small structures can use a large time step
interval. However, this approach requires inversion of
matrices which are generally not positive definite as in
explicit shemes for the first-order Maxwell’s equations
and thus becomes costly to solve for large problems. This
work presents an algorithm that exploits the sequential way
in which the subdomains are usually placed for layered
structures in packaging problems. Specifically, a reordering
of interface and volume unknowns combined with a block LDU
(Lower-Diagonal-Upper) decomposition allows improvements in
terms of memory cost and time of execution, with respect to
previous DGTD implementations.},
Doi = {10.2528/pier14112201},
Key = {fds283416}
}
@article{fds283421,
Author = {Lei, SW and Zhao, ZQ and Nie, ZP and Liu, QH},
Title = {A fast method for the optimization of polarimetric contrast
enhancement in partially polarized condition},
Journal = {Dianzi Keji Daxue Xuebao/Journal of the University of
Electronic Science and Technology of China},
Volume = {44},
Number = {1},
Pages = {55-60},
Year = {2015},
Month = {January},
ISSN = {1001-0548},
url = {http://dx.doi.org/10.3969/j.issn.1001-0548.2015.01.009},
Abstract = {A general signal to clutter plus noise ratio (SCNR) model
containing the partially polarized condition is created.
Based on this SCNR model, a fast method for the optimization
of the polarimetric contrast enhancement (OPCE) problem with
constrained transmitted and received polarization is
proposed. The method proves the OPCE problem equivalent to
the maximization of a linear cost function. The solving of
the maximization of the function is simpler than that of the
OPCE problem. Hence, the faster performance searching is
achieved. The method is theoretically deduced. The numerical
experiments demonstrate the effectiveness of this method.
Compared with the conventional global search method (GSM)
based on three-step method, the proposed method costs less
than 5% of the calculation time.},
Doi = {10.3969/j.issn.1001-0548.2015.01.009},
Key = {fds283421}
}
@article{fds283441,
Author = {Yang, H and Li, T and He, Z and Liu, QH},
Title = {Impulse borehole radar imaging based on compressive
sensing},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {12},
Number = {4},
Pages = {766-770},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {January},
ISSN = {1545-598X},
url = {http://dx.doi.org/10.1109/LGRS.2014.2361313},
Abstract = {A novel data acquisition and imaging method based on
compressive sensing is utilized for impulse borehole radar
(IBR). With the sparse transform that we present for IBR
systems, only 50% or even less samples are needed to be
collected and transmitted to reconstruct the target space,
which reduces the sampling rate and data transmission rate
of IBR systems. The simulation and experiment results show
that the proposed method is more robust in noise environment
and the reconstructed target spaces have less artifacts
compared with the solutions of the traditional Stolt
migration method.},
Doi = {10.1109/LGRS.2014.2361313},
Key = {fds283441}
}
@article{fds283455,
Author = {Lei, S and Zhao, Z and Nie, Z and Liu, QH},
Title = {Adaptive polarimetric detection method for target in
partially homogeneous background},
Journal = {Signal Processing},
Volume = {106},
Pages = {301-311},
Publisher = {Elsevier BV},
Year = {2015},
Month = {January},
ISSN = {0165-1684},
url = {http://dx.doi.org/10.1016/j.sigpro.2014.07.019},
Abstract = {In this paper, the problem of enhancing the detection
performance of detector for target in partially homogeneous
background is addressed. Based on a general measurement
model, a new constant false alarm rate (CFAR) adaptive
matched detector (AMD) is proposed through a two-step design
procedure. The detection performance of the AMD is
theoretically analyzed. Then, the correctness of the
analytical results and the effectiveness of the AMD are
validated through numerical experiments and IPIX radar data.
To further improve the detection performance of AMD, optimal
polarimetric waveform design is approached. The waveform is
designed by optimally selecting the transmitted polarization
that maximizes a non-central parameter of the detection
probability. Numerical experiments are provided to validate
the performance improvement by comparing the optimal AMD
with the optimal adaptive subspace detector (ASD) and the
fixed AMDs. Comparison results show that a gain of 1-5 dB is
obtained by the optimal AMD. © 2014 Elsevier
B.V.},
Doi = {10.1016/j.sigpro.2014.07.019},
Key = {fds283455}
}
@article{fds283459,
Author = {Wang, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {Electromagnetic inverse scattering series method for
positioning three-dimensional targets in near-surface
two-layer medium with unknown dielectric
properties},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {12},
Number = {2},
Pages = {299-303},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {January},
ISSN = {1545-598X},
url = {http://dx.doi.org/10.1109/LGRS.2014.2336983},
Abstract = {Positioning 3-D targets buried in layered medium with
electromagnetic waves has widespread applications, such as
the detection of land mines. Most of the current
electromagnetic inverse methods need to know the
preknowledge of the dielectric properties for layered
background medium, in order to accurately reconstruct
concealed targets. However, this condition is hardly
satisfied in real problems. In this letter, an
electromagnetic inverse scattering series method (EISSM) is
developed and derived for positioning 3-D targets buried in
two-layered medium. The prominent advantage of the proposed
method is that it does not need any prior information about
the dielectric properties of the layered medium. The
position error predicted by the EISSM is analyzed and
discussed. Compared with the commonly used
time-reversal-mirror technique, numerical simulations show
that the EISSM is capable of positioning the target buried
in two-layer medium with less error. © 2004-2012
IEEE.},
Doi = {10.1109/LGRS.2014.2336983},
Key = {fds283459}
}
@article{fds283468,
Author = {Zheng, J and Su, T and Zhu, W and Liu, QH},
Title = {A Fast Non-searching Algorithm for the High-Speed Target
Detection},
Journal = {Advances in Intelligent Systems and Computing},
Volume = {1089},
Pages = {777-782},
Publisher = {Springer International Publishing},
Year = {2015},
Month = {January},
ISSN = {2194-5357},
url = {http://dx.doi.org/10.1007/978-3-319-08422-0_112},
Abstract = {For the high-speed target detection, the linear range
migration induced by the high velocity disturbs the moving
target detection (MTD) algorithm, which can be efficiently
implemented via the fast Fourier transform (FFT). In this
paper, by employing a novel symmetric autocorrelation
function and the inverse fast Fourier transform (IFFT), a
fast non-searching algorithm is proposed to realize the
high-speed target detection. Compared to conventional
detection algorithms, this proposed fast algorithm can
complete the high-speed target detection and the motion
parameters estimation with lower computational cost and the
less complicated radar system. Furthermore, this fast
non-searching algorithm utilizes the radial velocity to
determine the high-speed target, which may provide a novel
idea for the echo processing of the high-speed target.
Through several numerical examples and analyses of the
computational cost, we verify the effectiveness of the fast
non-searching algorithm for the high-speed target detection.
© Springer International Publishing Switzerland
2015.},
Doi = {10.1007/978-3-319-08422-0_112},
Key = {fds283468}
}
@article{fds283469,
Author = {Zhang, W and Liu, QH},
Title = {Three-dimensional scattering and inverse scattering from
objects with simultaneous permittivity and permeability
contrasts},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {53},
Number = {1},
Pages = {429-439},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2015},
Month = {January},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2014.2322954},
Abstract = {There has been increasing efforts in enhanced biomedical and
geophysical imaging in the recent years exploring the
magnetic contrast agent. The handling of both dielectric and
magnetic contrasts adds on difficulties to the forward and
inverse scattering problems. In this paper, the 3-D
scattering and the inverse scattering from objects having
simultaneous electric and magnetic contrasts are presented,
where the permittivity, conductivity, and permeability of
the objects can all be different from the background. To
cope with the challenging high computation cost in the 3-D
scattering problem, we formulate the combined field volume
integral equations and extend the stabilized biconjugate
gradient method and fast Fourier transform (BCGS-FFT) method
to compute the electromagnetic field incorporating both the
electric and magnetic contrasts. The variational Born
iterative method for electrical contrast inversion in
axisymmetric media is generalized to 3-D and to the
simultaneous reconstruction of objects with electric and
magnetic contrasts. The BCGS-FFT method provides the
predicted scattered field from the 3-D heterogeneous objects
and the Fréchet derivatives in the inverse scattering
problem. The efficient forward solver also dramatically
reduces the computation time of the inverse problem.
Numerical results are presented to validate the forward
solver and to demonstrate the effectiveness of the inverse
scattering method. © 2014 IEEE.},
Doi = {10.1109/TGRS.2014.2322954},
Key = {fds283469}
}
@article{fds321750,
Author = {Ellis, MS and Zhao, Z and Wu, J and Nie, Z and Liu, QH},
Title = {Small planar monopole ultra-wideband antenna with reduced
ground plane effect},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {9},
Number = {10},
Pages = {1028-1034},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2015},
Month = {January},
url = {http://dx.doi.org/10.1049/iet-map.2014.0538},
Abstract = {A printed monopole ultra-wideband antenna with reduced
ground plane effect is presented. The ground plane
dependence of the antenna is reduced by cutting a slot in
the radiator, and then introducing a strip in the slot, to
reduce the current distribution on the ground plane at a
desired frequency. At this frequency, the impedance
performance of the antenna is mainly affected by the
monopole radiator, thus reducing the effect of the ground
plane on the antenna. Measurement results confirm that this
approach works well and also show good far-field properties
of the antenna. The antenna is printed on a small FR4
substrate with an area of 25 mm2; it achieves an impedance
bandwidth of 3.6 to over 11 GHz, and broadband ground plane
effect suppression around the design frequency of 5
GHz.},
Doi = {10.1049/iet-map.2014.0538},
Key = {fds321750}
}
@article{fds341216,
Author = {Zhan, Q and Ren, Q and Sun, Q and Liu, QH},
Title = {Discontinuous Galerkin pseudospectral time domain algorithm
(DG-PSTD) with auxiliary ordinary differential equations
perfectly matched layer (AODE-PML) for 3D seismic
modelling},
Journal = {Seg Technical Program Expanded Abstracts},
Volume = {34},
Pages = {3633-3638},
Year = {2015},
Month = {January},
url = {http://dx.doi.org/10.1190/segam2015-5837639.1},
Abstract = {A discontinuous Galerkin pseudospectral time domain (DGPSTD)
algorithm is proposed for the elastic wave propagation
problem in unbounded domains, where an equivalent but
significantly simpler auxiliary ordinary differential
equations (AODEs) formulation of 3D perfectly matched layer
(PML) is used to truncate the computational domain. A more
accurate Riemann solver, i.e., the Godunov flux is provided
to not only resolve the coupling of subdomains but also give
an explicit guideline for the new governing equations in the
PML region. The proposed DGPSTD algorithm combines the
merits of flexibility from a finite element method and
spectral accuracy and efficiency from a high-order
pseudospectral method while having a flavor closer to a
finite volume method. Test results show that the newly
proposed AODE-PML needs only oneelement PML layer to absorb
outgoing waves efficiently and sufficiently.},
Doi = {10.1190/segam2015-5837639.1},
Key = {fds341216}
}
@article{fds322895,
Author = {Li, N and Cui, G and Yang, H and Kong, L and Liu, QH},
Title = {Adaptive detection of distributed targets in Gaussian
clutter without secondary data: An approach based on
multiple a-priori spectral models},
Journal = {Iet Conference Publications},
Volume = {2015},
Number = {CP677},
Year = {2015},
Month = {January},
ISBN = {9781785610387},
url = {http://dx.doi.org/10.1049/cp.2015.1119},
Abstract = {In this paper, we consider the problem of adaptive detection
for distributed targets embedded in Gaussian disturbance
without secondary data. Suppose that some apriori spectral
models for the interference in the cells under test and a
lower bound on the power spectral density (PSD) of the white
disturbance term are available. First, we propose an
approximate estimate algorithm for the unknown parameters
based on a heuristic approach under both the hypothesis.
Then, an approximate Generalized Likelihood Ratio Test
(GLRT) is proposed by exploiting the heuristic estimates.
Finally, we evaluate the capabilities of the proposed
detector against Gaussian disturbance as well as their
superiority with respect to some existing
techniques.},
Doi = {10.1049/cp.2015.1119},
Key = {fds322895}
}
@article{fds322896,
Author = {Li, N and Cui, G and Yang, H and Kong, L and Liu, QH},
Title = {Adaptive detection of distributed targets in
compound-Gaussian clutter without secondary data: An
approach based on multiple a-priori spectral
models},
Journal = {Iet Conference Publications},
Volume = {2015},
Number = {CP677},
Year = {2015},
Month = {January},
ISBN = {9781785610387},
url = {http://dx.doi.org/10.1049/cp.2015.1120},
Abstract = {In this paper, we consider the problem of adaptive detection
for distributed targets embedded in compound-Gaussian
clutter without secondary data. Suppose that some a-priori
spectral models for the clutter in the cells under test are
available. First, we propose an approximate estimate
algorithm for the unknown parameters based on a heuristic
approach under both the hypothesis. Then, an approximate
Generalized Likelihood Ratio Test (GLRT) is proposed by
exploiting the heuristic estimates. Finally, we evaluate the
capabilities of the proposed detector against
compound-Gaussian clutter as well as their superiority with
respect to some existing techniques.},
Doi = {10.1049/cp.2015.1120},
Key = {fds322896}
}
@article{fds322897,
Author = {Li, N and Cui, G and Yang, H and Kong, L and Liu, QH},
Title = {Knowledge-aided Bayesian detection with MIMO radar in
compound-Gaussian clutter},
Journal = {Iet Conference Publications},
Volume = {2015},
Number = {CP677},
Year = {2015},
Month = {January},
ISBN = {9781785610387},
url = {http://dx.doi.org/10.1049/cp.2015.1118},
Abstract = {In this paper, we consider the adaptive detection with
multiple-input multiple-output (MIMO) radar in the presence
of compound-Gaussian clutter. A Bayesian framework is
exploited where the covariance matrices of the primary and
the secondary data are assumed to be random, with an inverse
complex Wishart distribution. In this framework, the
generalized likelihood ratio test (GLRT) is derived.
Finally, we evaluate the capabilities of the proposed
detector against compound-Gaussian clutter as well as their
superiority with respect to some existing
techniques.},
Doi = {10.1049/cp.2015.1118},
Key = {fds322897}
}
@article{fds283454,
Author = {Ye, G and Deng, C and Liu, QH},
Title = {The PSTD method with the 4th-order time integration for 3D
TAT reconstruction of a breast model},
Journal = {Journal of Computational Acoustics},
Volume = {22},
Number = {4},
Pages = {1450011-1450011},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {2014},
Month = {December},
ISSN = {0218-396X},
url = {http://dx.doi.org/10.1142/S0218396X14500118},
Abstract = {The thermoacoustic tomography (TAT) is a novel noninvasive
and nonionizing medical imaging modality for breast cancer
detection. In the TAT, a short pulse of microwave is
irradiated to the breast tissue. The tissue absorbs the
microwave energy and is heated up momentarily, thus it
generates acoustic waves due to the thermoelastic expansion.
If the pulse width of the microwave radiation is around one
microsecond, the generated acoustic waves are ultrasonic and
are in the MHz range. Wide-band ultrasonic transducers are
employed to acquire the time-resolved ultrasound signals,
which carry information about the microwave absorption
properties (mainly related to conductivities) of different
tissues. An image showing such properties can then be
reconstructed from the time-resolved ultrasound signals.
Most existing TAT reconstruction methods are based on the
assumption that the tissue under study is acoustically
homogeneous. In practice, however, most biological tissues
are inhomogeneous. For example, the speed of sound has about
10% variation in breast tissue. The acoustic heterogeneity
will cause phase distortion of the pressure field, which
will in turn cause blurring in the reconstructed image, thus
limiting the ability to resolve small objects. In this work,
a 3D inhomogeneous reconstruction method based on
pseudo-spectral time-domain (PSTD) is presented to overcome
this problem. The method includes two steps. The first step
is a homogeneous reconstruction process, from which an
initial image is obtained. Since the inhomogeneity itself is
usually an acoustic source, the shape and location of the
inhomogeneity can be estimated. Then, the acoustic
properties of the inhomogeneities (available from the
literatures for known tissue types) are assigned to the
classified regions, and the other reconstruction based on
the updated acoustic property map is conducted. With this
process, the phase distortion can be effectively corrected.
So it can improve the ability to image small objects. A 3D
breast phantom is used to study the proposed method. The
breast phantom was generated based on the data set of the
Visible Human Project. Regions of different tissue types
have been classified and acoustic and electric properties
are assigned to such regions. Small phantom tumors placed in
the breast phantom have been reconstructed successfully with
the inhomogeneous reconstruction method. Improved resolution
has been achieved compared to that obtained by homogeneous
method.},
Doi = {10.1142/S0218396X14500118},
Key = {fds283454}
}
@article{fds283394,
Author = {Zhao, Y and Zhang, L and Xu, X and Yu, F and Liu, Q},
Title = {A GA based real-time voltage platform for a 32-element high
gain beam-forming antenna optimization},
Journal = {Proceedings of 3rd Asia Pacific Conference on Antennas and
Propagation, Apcap 2014},
Pages = {917-919},
Publisher = {IEEE},
Year = {2014},
Month = {December},
ISBN = {9781479943548},
url = {http://dx.doi.org/10.1109/APCAP.2014.6992650},
Abstract = {In this paper, a real-time voltage control platform,
based-on genetic algorithm (GA) program, is built to
optimize a 32-element high gain beam-forming antenna. After
500 generations, S21 has been significantly improved. The
gain of the antenna has promoted to 8.95dBi, and the
beam-width of the antenna has narrowed down to
30°.},
Doi = {10.1109/APCAP.2014.6992650},
Key = {fds283394}
}
@article{fds283395,
Author = {Xu, X and Zhao, Y and Yu, F and Zhang, L and Liu, Q},
Title = {A novel horizontal polarization sensitive Active Frequency
Selective Surface without biasing network at 2.4GHz WiFi
band},
Journal = {Proceedings of 3rd Asia Pacific Conference on Antennas and
Propagation, Apcap 2014},
Pages = {277-279},
Publisher = {IEEE},
Year = {2014},
Month = {December},
ISBN = {9781479943548},
url = {http://dx.doi.org/10.1109/APCAP.2014.6992473},
Abstract = {A novel horizontal polarization sensitive Active Frequency
Selective Surface (AFSS) without biasing networks at 2.4GHz
WiFi band is presented. The AFSS structure is composed of
two mirrored parts and a varactor is set to connect them.
Resistors put between the unit cells are used to provide DC
connections. No additional biasing networks is required. The
structure is sensitive to horizontal polarization wave,
which is perpendicular to the unit extending direction.
Simulation results show that the structure can offer a wide
tunable frequency range from 2.21GHz to 2.71GHz. This
behavior makes the AFSS structure suitable for the design of
Electronically Steerable Radiator and Reflector Array
(ESRRA) antenna at 2.4GHz WiFi band.},
Doi = {10.1109/APCAP.2014.6992473},
Key = {fds283395}
}
@article{fds283424,
Author = {Yao, Z and Liu, Y and Xiong, X and Zhang, L and Ye, L and Liu,
QH},
Title = {A novel hole drilling method for plate Luneberg lens
antenna},
Journal = {Proceedings of 3rd Asia Pacific Conference on Antennas and
Propagation, Apcap 2014},
Pages = {444-446},
Publisher = {IEEE},
Year = {2014},
Month = {December},
ISBN = {9781479943548},
url = {http://dx.doi.org/10.1109/APCAP.2014.6992521},
Abstract = {This article presents a novel plate Luneberg lens which is
based on the parallel plate waveguide filled with drilled
dielectric material. To obtain effectively refractive index
distribution, several small holes of nonuniform density are
drilled in this dielectric. In order to meet Luneberg Law's
requirement on the edge region, the thickness of the
substrate is modified by the boundary conditions of
electromagnetic fields. As the feeding structure, a
single-ridge waveguide is integrated into this plate lens
antenna.},
Doi = {10.1109/APCAP.2014.6992521},
Key = {fds283424}
}
@article{fds283425,
Author = {Xiong, X and Liu, Y and Yao, Z and Zhang, L and Li, W and Liu,
QH},
Title = {Design of a metasurface Luneburg lens antenna with flared
structure},
Journal = {Proceedings of 3rd Asia Pacific Conference on Antennas and
Propagation, Apcap 2014},
Pages = {375-378},
Publisher = {IEEE},
Year = {2014},
Month = {December},
ISBN = {9781479943548},
url = {http://dx.doi.org/10.1109/APCAP.2014.6992501},
Abstract = {This article demonstrates the design of a meta-surface
Luneburg lens antenna with flared structure. The lens
antenna is composed of two flared metallic cones, a
metasurface Luneburg lens and a reflection plate. The
refraction index of Luneburg lens can be obtained by
gradually changing the radius of patch arraying on the
substrate. Such an antenna structure is easy to implement
with low fabrication error. Some modified methods are
applied to improve the radiation performance of this
antenna. Simulation results show that the designed
metasurface Luneburg lens antenna has a focused beam pattern
with relatively low sidelobe level.},
Doi = {10.1109/APCAP.2014.6992501},
Key = {fds283425}
}
@article{fds283426,
Author = {Liu, Y and You, P and Chen, S and Zhang, L and Liu, QH},
Title = {Antenna selection in the synthesis of mutlple-pattern linear
arrays by iterative linear programming},
Journal = {Proceedings of 3rd Asia Pacific Conference on Antennas and
Propagation, Apcap 2014},
Pages = {201-204},
Publisher = {IEEE},
Year = {2014},
Month = {December},
ISBN = {9781479943548},
url = {http://dx.doi.org/10.1109/APCAP.2014.6992452},
Abstract = {The problem of selecting antennas for synthesizing
multiple-pattern linear arrays is considered. It is shown
that this problem can be solved by an iterative linear
programming procedure. Only few iterations are required for
this procedure to reach the convergence. The synthesis
results show that the proposed method can select the optimum
element positions and consequently reduces the number of
elements, while the synthesized multiple patterns can meet
the specified multiple pattern bounds.},
Doi = {10.1109/APCAP.2014.6992452},
Key = {fds283426}
}
@article{fds283419,
Author = {Lei, S and Zhao, Z and Nie, Z and Liu, QH},
Title = {An adaptive subspace detector for target in target-induced
clutter plus Gaussian noise background},
Journal = {2014 Ieee International Conference on Signal Processing,
Communications and Computing, Icspcc 2014},
Pages = {234-238},
Publisher = {IEEE},
Year = {2014},
Month = {December},
ISBN = {9781479952748},
url = {http://dx.doi.org/10.1109/ICSPCC.2014.6986189},
Abstract = {In this paper, we consider the problem of detecting target
in target-induced clutter (TIC) plus Gaussian noise
background. Processing this detection problem, the
traditional generalized likelihood ratio detector (GLRD)
deals with the clutter as a part of the noise. An adaptive
subspace detector for TIC (TIC-ASD) background is proposed.
Different from the traditional GLRD, the TIC-ASD deals with
the clutter and the noise separately. The signal and the
clutter covariance matrix are estimated with the aid of
generalized likelihood ratio (GLR) principle. The test
statistic is constructed by replacing the signal and the
clutter covariance matrix with their maximum likelihood
estimations (MLEs). Experimental simulations are provided to
demonstrate the detection performance of the TIC-ASD and the
GLRD. Simulation results show that the TIC-ASD outperforms
the GLRD in both single antenna and multi antenna
scenarios.},
Doi = {10.1109/ICSPCC.2014.6986189},
Key = {fds283419}
}
@article{fds283434,
Author = {Liu, J and Zhao, Z and Yuan, M and Ybarra, GA and Liu,
QH},
Title = {The filter diagonalization method in antenna array
optimization for pattern synthesis},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {62},
Number = {12},
Pages = {6123-6130},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {December},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2014.2364818},
Abstract = {Pattern synthesis of nonuniform antenna arrays has drawn
significant attention because of its wide applications. With
the aim of reducing the number of elements in linear and
planar arrays, this paper introduces a novel non-iterative
method based on the filter diagonalization method (FDM),
which was originally applied in the problem of identifying
and quantifying chemical molecules with nuclear magnetic
resonance (NMR) in quantum mechanical formalism. The
proposed method samples the data set from the desired
discrete pattern and associates the sample data with a time
autocorrelation function of a fictitious dynamical system,
which is described by an effective "Hamiltonian" operator
that contains the array element information. The
"Hamiltonian" operator can be decomposed by a set of
orthonormal eigenvectors. Therefore, the original pattern
synthesis is converted into solving the general eigenvalue
decomposition with Krylov bases. The number of nonuniform
array elements depends on the number of the Krylov bases and
the sample data. The proposed method can obtain an optimized
antenna array to reconstruct the desired radiation pattern
with a high accuracy. Numerical examples show that proposed
FDM pattern synthesis can use less prior knowledge to
achieve the desired pattern with highly sparse antenna
arrays.},
Doi = {10.1109/TAP.2014.2364818},
Key = {fds283434}
}
@article{fds283443,
Author = {Feng, N and Liu, QH},
Title = {Efficient implementation of multi-pole UPML using
trapezoidal approximation for general media},
Journal = {Journal of Applied Geophysics},
Volume = {111},
Pages = {59-65},
Publisher = {Elsevier BV},
Year = {2014},
Month = {December},
ISSN = {0926-9851},
url = {http://dx.doi.org/10.1016/j.jappgeo.2014.09.020},
Abstract = {Based on the uniaxial anisotropic perfectly matched layer
(UPML) with multi-poles, unsplit-field implementation of the
higher-order PML using the trapezoidal approximation (TA)
method is proposed to terminate the finite-difference
time-domain (FDTD) computational domains. From the point of
view of the Courant-Friedrichs-Levy (CFL) condition, to the
best of our knowledge, time step based on the TA only needs
to meet CFL condition, whereas time step based on the
matched Z-transform (MZT) method has to make it smaller for
retaining stability and desirable accuracy. Moreover, these
formulations are completely independent of the material
properties of the FDTD domains and hence can be applied to
truncate arbitrary media without any modification because of
the D-B constitutive relations used in Maxwell's equations.
Four numerical examples have been carried out in three
dimensional (3D) FDTD computational domains to validate
these formulations. It is shown that the proposed UPML
formulations with two poles are effective in terms of
attenuating both the low-frequency propagating waves and
evanescent waves and reducing late-time reflections, and
also can produce results as accurate as the published
MZT-UPML but with fewer number of steps and less CPU
time.},
Doi = {10.1016/j.jappgeo.2014.09.020},
Key = {fds283443}
}
@article{fds283430,
Author = {Hu, Y and Zhang, W and Liu, QH},
Title = {Multiphysics coupling of dynamic fluid flow and
electromagnetic fields for subsurface sensing},
Journal = {2014 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2014 Proceedings},
Pages = {242},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISBN = {9781479937462},
url = {http://dx.doi.org/10.1109/USNC-URSI.2014.6955625},
Abstract = {Electromagnetic (EM) measurement has been extensively
applied in subsurface sensing while fluid flow modeling is
capable of characterizing subsurface fluid flow behavior.
The multiphysics coupling of the EM measurement and dynamic
fluid flow analysis has significant potential to improve
electromagnetic geophysical exploration with injecting
electromagnetic contrast agents.},
Doi = {10.1109/USNC-URSI.2014.6955625},
Key = {fds283430}
}
@article{fds283431,
Author = {Ren, Q and Tobon, LE and Sun, Q and Liu, QH},
Title = {The hybrid SETD-FETD method with field variables e and
B},
Journal = {2014 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2014 Proceedings},
Pages = {68},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISBN = {9781479937462},
url = {http://dx.doi.org/10.1109/USNC-URSI.2014.6955450},
Abstract = {The discontinuous Galerkin Time Domain (DGTD) methods, such
as DG-SETD and DG-FETD, are shown to be effective in the
simulation of multiscale, transient problems. It can solve
large problems by dividing the computational domain into
several subdomains, thus the large system matrix is
transformed into a few moderate-sized matrices. The
computation resource required for solving these matrices is
much less than solving the original large one. The numerical
fluxes are employed to fulfill the energy communication
between adjacent subdomains.},
Doi = {10.1109/USNC-URSI.2014.6955450},
Key = {fds283431}
}
@article{fds283433,
Author = {Yu, Z and Zhang, W and Zhou, J and Liu, QH},
Title = {Application of mixed order BCGS-FFT on contrast enhanced oil
reservoir imaging},
Journal = {2014 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2014 Proceedings},
Pages = {175},
Publisher = {IEEE},
Year = {2014},
Month = {November},
ISBN = {9781479937462},
url = {http://dx.doi.org/10.1109/USNC-URSI.2014.6955557},
Abstract = {With the rapid advancements in material science and
manufacturing technology, applications of materials with
special properties have been widely expanded. Some specially
made nanoparticles can be used as contrast agents to change
the contrast modalities (ε, μ, and σ) of the unknown
objects in electromagnetic imaging problem to improve the
imaging quality. Due to the potentials of the enhanced
contrast imaging, many attempts have recently been made to
apply this technique to various fields, for example oil
reservoir imaging. In the application of the contrast
enhanced oil reservoir imaging, nanoparticles with large
permittivity, magnetic permeability and/or electrical
conductivity are injected to the reservoir through the
injection well. As the nanoparticles propagate into the
reservoir, the three contrast modalities of the oil can be
significantly changed depending on the fluid saturation
rate. The enhanced contrasts of the oil can result in a
stronger scattered signal which will lead to an enhancement
in imaging result. However, the low operating frequency and
large contrast modalities of the nanoparticles can be
challenging for currently available electromagnetic field
solvers for scattering problems.},
Doi = {10.1109/USNC-URSI.2014.6955557},
Key = {fds283433}
}
@article{fds283444,
Author = {Yu, Z and Zhang, W and Liu, QH},
Title = {A mixed-order stabilized bi-conjugate gradient FFT method
for magnetodielectric objects},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {62},
Number = {11},
Pages = {5647-5655},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {November},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2014.2352634},
Abstract = {Magnetodielectric materials have many emerging applications,
but their scattering problems are challenging for volume
integral equation solvers. In this paper, a mixed-order
stabilized bi-conjugate gradient FFT (mixed-order BCGS-FFT)
method for solving the scattering problem of
magnetodielectric objects is presented. This method uses the
volumetric roof-top basis functions as testing functions for
the coupled field volume integral equation (CFVIE) and basis
functions for the electric and magnetic flux densities
(D,B). However, unlike the conventional weak form BCGS-FFT
methods for dielectric objects, the mixed-order BCGS-FFT
method uses the second-order curl conforming basis functions
for the electric and magnetic vector potentials (F,A). The
curl conforming basis functions preserve the continuity of
the tangential components for F and A, while the use of
second-order basis functions avoids the zero terms caused by
the divergence operations on the vector potentials.
Numerical examples show excellent performance of the
mixed-order BCGS-FFT method over the currently available
BCGS-FFT method as well as high accuracy of the mixed-order
BCGS-FFT method on large contrast magnetodielectric
scatterers.},
Doi = {10.1109/TAP.2014.2352634},
Key = {fds283444}
}
@article{fds283428,
Author = {Liu, Y and Chen, S and Zhang, L and Liu, QH},
Title = {Generalization of matrix pencil methods to the synthesis of
wideband aperiodic linear arrays with frequency-invariant
patterns},
Journal = {2014 31th Ursi General Assembly and Scientific Symposium,
Ursi Gass 2014},
Publisher = {IEEE},
Year = {2014},
Month = {October},
ISBN = {9781467352253},
url = {http://dx.doi.org/10.1109/URSIGASS.2014.6929090},
Abstract = {The problem of generalizing the matrix pencil methods (MPM)
to the synthesis of wideband aperiodic arrays with
frequency-invariant (FI) patterns is considered. A new
pattern sampling strategy is presented to obtain the
multiple pattern data of different frequencies having the
common poles. The generalized MPM (GMPM) and its
forward-backward version (GFBMPM) are developed to find the
best common element positions for different frequencies,
which can significantly reduce the number of elements
required for the desired pattern shape. Numerical examples
are presented to validate the effectiveness and advantages
of the proposed methods.},
Doi = {10.1109/URSIGASS.2014.6929090},
Key = {fds283428}
}
@article{fds283429,
Author = {Chen, S and Liu, Y and Ren, Y and Liu, QH},
Title = {A broadband dual-polarized microstrip antenna with
cavity-backed proximity-coupling feeding},
Journal = {2014 31th Ursi General Assembly and Scientific Symposium,
Ursi Gass 2014},
Publisher = {IEEE},
Year = {2014},
Month = {October},
ISBN = {9781467352253},
url = {http://dx.doi.org/10.1109/URSIGASS.2014.6929080},
Abstract = {A broadband cavity-backed proximity-coupled dual-polarized
microstrip antenna is presented. The cavity backed ground
plane is used with optimized parameters to enhance the
feeding coupling and thus to broaden the bandwidth of this
antenna. A prototype antenna is designed and fabricated.
Simulation and measurement results show that the proposed
design achieves S11 ≤ -10 dB bandwidth of more than 30%
(8.2-11.4 GHz) and the port isolation is larger than 20 dB
over that band. This antenna is easy to fabricate, and can
be directly mounted on the metal body surface in
application.},
Doi = {10.1109/URSIGASS.2014.6929080},
Key = {fds283429}
}
@article{fds321752,
Author = {Lei, S and Zhao, Z and Nie, Z and Liu, QH},
Title = {A CFAR Adaptive Subspace Detector Based on a Single
Observation in System-Dependent Clutter Background},
Journal = {Ieee Transactions on Signal Processing},
Volume = {62},
Number = {20},
Pages = {5260-5269},
Year = {2014},
Month = {October},
url = {http://dx.doi.org/10.1109/TSP.2014.2348952},
Abstract = {In this paper, the problem of detecting target in
system-dependent clutter (SDC) background with a single
observation from the test cell is researched. Classical
detectors, such as the generalized likelihood ratio
detectors (GLRDs) and the adaptive matched filters (AMFs),
etc., usually deal with the clutter and the noise as a
whole. The low rank detectors (LRDs) make use of the low
rank property of the clutter to improve the detection
performance. However, the performance of LRDs degrades when
the signal is not orthogonal with respect to (w.r.t.) the
clutter. In this paper, an adaptive subspace detector for
SDC (SDC-ASD) background which deals with the clutter and
the noise separately is proposed. The SDC-ASD designs the
test statistic by replacing the signal and the clutter
covariance matrix with their maximum likelihood estimations
(MLEs). Its theoretical false alarm probability and
detection probability are analytically deduced. Analytical
results show that the test statistic has the form of
non-central $F$ distribution. Besides, it is shown that the
SDC-ASD has constant false alarm rate (CFAR) performance
w.r.t. the clutter and the noise. Numerical experiments are
provided to validate the detection performance of the
SDC-ASD in dealing with the target detection in SDC
background.},
Doi = {10.1109/TSP.2014.2348952},
Key = {fds321752}
}
@article{fds283456,
Author = {Niu, J and Luo, M and Fang, Y and Liu, QH},
Title = {Boundary integral spectral element method analyses of
extreme ultraviolet multilayer defects.},
Journal = {Journal of the Optical Society of America
A},
Volume = {31},
Number = {10},
Pages = {2203-2209},
Year = {2014},
Month = {October},
ISSN = {1084-7529},
url = {http://dx.doi.org/10.1364/josaa.31.002203},
Abstract = {Extreme ultraviolet (EUV) lithography is an emerging
technology for high-density semiconductor patterning.
Multilayer distortion caused by mask defects is regarded as
one of the critical challenges of EUV lithography. To
simulate the influence of the defected nanoscale structures
with high accuracy and efficiency, we have developed a
boundary integral spectral element method (BI-SEM) that
combines the SEM with a set of surface integral equations.
The SEM is used to solve the interior computational domain,
while the open boundaries are truncated by the surface
integral equations. Both two-dimensional (2D) and
three-dimensional (3D) EUV cases are simulated. Through
comparing the performance of this method with the
conventional finite element method (FEM), it is shown that
the proposed BI-SEM can greatly decrease both the memory
cost and the computation time. For typical 2D problems, we
show that the BI-SEM is 11 and 1.25 times more efficient
than the FEM in terms of memory and CPU time, respectively,
while for 3D problems, these factors are over 14 and 2,
respectively, for smaller problems; realistic 3D problems
that cannot be solved by the conventional FEM can be
accurately simulated by the BI-SEM.},
Doi = {10.1364/josaa.31.002203},
Key = {fds283456}
}
@article{fds283445,
Author = {Ren, Q and Liu, QH},
Title = {New DG-SETD method for 3D em simulations},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2250-2251},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6905452},
Abstract = {A new discontinuous Galerkin Spectral Element Time Domain
(SETD) method for Maxwell's Equations is proposed. It can
suppress spurious modes using basis functions with the same
order of interpolation for electric field intensity and
magnetic flux density (i.e. the EB scheme). Compared to SETD
based on the EH scheme, which requires different order of
interpolation polynomials for electric and magnetic field
intensities, the EB scheme SETD reduces the number of
unknowns and computation cost. The discontinuous Galerkin
method is employed to implement domain decomposition for the
EB scheme to allow large-scale computation.},
Doi = {10.1109/APS.2014.6905452},
Key = {fds283445}
}
@article{fds283446,
Author = {Niu, J and Luo, M and Liu, QH},
Title = {Boundary integral spectral element method for extreme
ultraviolet multilayer defects analyses},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1994-1995},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6905324},
Abstract = {The multilayer distortion caused by the mask defects is
regarded as one of the critical challenges of extreme
ultraviolet (EUV) lithography for high density semiconductor
patterning. To numerically analyze the influence of the
defected nano-scale structures with high accuracy and
efficiency, we have developed a boundary integral spectral
element method (BI-SEM) that combines the SEM with a set of
surface integral equations. The SEM is used to solve the
interior computational domain, while the open boundaries are
truncated by the surface integral equations. Through
comparing the performance of this method with the
conventional finite element method, it is shown that the
proposed BI-SEM can greatly decrease both the memory cost
and computation time.},
Doi = {10.1109/APS.2014.6905324},
Key = {fds283446}
}
@article{fds283447,
Author = {Sun, Q and Liu, QH},
Title = {A new DG-FETD implicit time stepping scheme based on e and B
fields for sequentially ordered systems},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2248-2249},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6905451},
Abstract = {Based on curl-conforming basis functions and
divergence-conforming basis functions for E and B fields, a
new non-interative implicit time stepping scheme is proposed
to efficiently solve sequentially ordered systems. The new
scheme features a reordering of the linear system and a
block LDU (lower-diagonal-upper) decomposition, thereby
reducing the computational complexity of the original
system.},
Doi = {10.1109/APS.2014.6905451},
Key = {fds283447}
}
@article{fds283449,
Author = {Yu, Z and Zhang, W and Liu, QH},
Title = {Mixed order integral equation formulation for the scattering
from large inhomogeneous anisotropic magnetodielectric
objects},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2126-2127},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6905390},
Abstract = {We propose a mixed order formulation of the combined field
volume integral equation (CFVIE) for inhomogeneous
anisotropic magnetodielectric objects. This method uses the
Rao-Wilton-Glisson (RWG) basis functions to expand flux
densities while second order curl conforming basis functions
are used to expand vector potentials. In this case, both
dielectric and magnetic contrasts of the objects can be
accounted for in the CFVIE formulation. Moreover, correct
boundary conditions are imposed on both flux densities and
vector potentials. Finally, the stabilized bi-conjugate
gradient fast Fourier transform (BCGS-FFT) method is
employed to solve the integral equations. Numerical examples
show that this method can handle large size objects with
inhomogeneous or anisotropic magnetodielectric materials.
The scattered fields calculated by this method have
excellent agreement with both MIE solution and the results
from commercial software.},
Doi = {10.1109/APS.2014.6905390},
Key = {fds283449}
}
@article{fds283450,
Author = {Yang, H and Li, T and He, Z and Liu, QH},
Title = {Design and analysis of an impulse borehole radar for well
logging},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1614-1615},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6905133},
Abstract = {An impulse-based single-borehole radar prototype has been
developed for well logging. The borehole radar is comprised
of subsurface sonde and surface equipment. An armored
7-conductor well logging cable is used to connect subsurface
sonde and surface equipment which is well compatible with
the other well logging instruments. The performance
experiments of the prototype have been conducted in a test
field. The results show that the prototype system is capable
of detecting the target 8 meters away from the borehole.
This radar prototype has been employed in a real oil field
well. Compared with conventional resistivity well logging
tools, the prototype system provides comprehensive well-bore
formation analysis information.},
Doi = {10.1109/APS.2014.6905133},
Key = {fds283450}
}
@article{fds283451,
Author = {Xu, K and Zhang, Y and Joines, WT and Liu, QH},
Title = {Planar interdigital-coupled UWB bandpass filter with a
notched band},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1694-1695},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6905173},
Abstract = {This paper presents a planar compact microstrip
interdigital-coupled notch-band ultra-wideband (UWB)
bandpass filter (BPF). The proposed five high-impedance
interdigital lines are employed to not only realize strong
coupling as feed lines, but also create a controllable
notched band in the UWB passband. A prototype of the
proposed notch-band UWB BPF has been designed and
fabricated. The measured results illustrate that the 3 dB
fractional bandwidth (FBW) of the filter is 125%, and the
insertion loss of the notched band within the UWB passband
is 12 dB at 5.8 GHz.},
Doi = {10.1109/APS.2014.6905173},
Key = {fds283451}
}
@article{fds283452,
Author = {Xu, K and Zhang, Y and Joines, WT and Liu, QH},
Title = {Compact planar antenna for triple frequency band
operation},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {789-790},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6904724},
Abstract = {A novel triple band planar antenna using a four-stub-loaded
ring-slot on the ground and a U-slot on the microstrip-fed
line is presented. The ring slot is designed to drive two
different resonant modes, and the four T-shaped stubs are
loaded to lower these two resonant frequencies. Moreover, a
U-shaped slot etched on the microstrip feeding line is to
excite a third upper frequency band without increasing the
overall size of the antenna. The computational analysis and
measurement illustrate that the proposed antenna can cover
three frequency bands of 2.4, 3.5, and 5.8 GHz with good
return losses and stable radiation patterns.},
Doi = {10.1109/APS.2014.6904724},
Key = {fds283452}
}
@article{fds283453,
Author = {Liu, J and Zhao, Z and Yang, K and Liu, QH},
Title = {Sum and difference pattern synthesis with antenna
correction},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {113-114},
Publisher = {IEEE},
Year = {2014},
Month = {September},
ISBN = {9781479935406},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2014.6904388},
Abstract = {A fast iterative method for minimizing the peak sidelobe
level of an antenna array is presented, which is based on
the non-uniform fast Fourier transform (NUFFT). Due to an
inverse Fourier transform relationship between the array
factor and the element excitation, the FFT can be used for
optimizing the element excitation and array factor
alternatively by interpolating the non-uniform arrays into
oversample virtual uniform arrays. During the whole
iteration, the mainlobe is kept unchanged and the sidelobe
level is adjusted. For demonstration, the pattern correction
of the sum and difference pattern are implemented by the
proposed algorithm.},
Doi = {10.1109/APS.2014.6904388},
Key = {fds283453}
}
@article{fds283465,
Author = {Yu, Z and Chai, M and Mix, JA and Slattery, KP and Liu,
QH},
Title = {Inverse Source Solver for a High Resolution Near Field
Scanner in Microelectronic Applications},
Journal = {Ieee Transactions on Components, Packaging and Manufacturing
Technology},
Volume = {4},
Number = {9},
Pages = {1495-1502},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {September},
ISSN = {2156-3950},
url = {http://dx.doi.org/10.1109/TCPMT.2014.2339357},
Abstract = {A potential application of inverse source solver for high
resolution near field scanning of microelectronic packages
is studied in this paper. A fast inverse source solver based
on the fast Fourier transform algorithm and conjugate
gradient algorithm is developed with a half-space Green's
function. This solver can be used in microelectronic
applications to solve radiation related problems, including
electromagnetic interference and signal integrity of printed
circuit boards or integrated circuit packagings. Simulation
results show a significant improvement in image resolution
and adjacent sources detectability when the inverse source
solver is applied. Because of the improvements, the inverse
source solver reduces the sensitivity on scan height in the
near field scan process when the same source image
resolution is desired. Experiments on measured data also
validate the effectiveness of this solver.},
Doi = {10.1109/TCPMT.2014.2339357},
Key = {fds283465}
}
@article{fds283479,
Author = {Zhu, X and Zhao, Z and Wang, J and Chen, G and Liu, QH},
Title = {Active adjoint modeling method in microwave induced
thermoacoustic tomography for breast tumor.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {61},
Number = {7},
Pages = {1957-1966},
Year = {2014},
Month = {July},
ISSN = {0018-9294},
url = {http://dx.doi.org/10.1109/tbme.2014.2309912},
Abstract = {To improve the model-based inversion performance of
microwave induced thermoacoustic tomography for breast tumor
imaging, an active adjoint modeling (AAM) method is
proposed. It aims to provide a more realistic breast
acoustic model used for tumor inversion as the background by
actively measuring and reconstructing the structural
heterogeneity of human breast environment. It utilizes the
reciprocity of acoustic sensors, and adapts the adjoint
tomography method from seismic exploration. With the
reconstructed acoustic model of breast environment, the
performance of model-based inversion method such as time
reversal mirror is improved significantly both in contrast
and accuracy. To prove the advantage of AAM, a checkerboard
pattern model and anatomical realistic breast models have
been used in full wave numerical simulations.},
Doi = {10.1109/tbme.2014.2309912},
Key = {fds283479}
}
@article{fds283440,
Author = {Wu, J and Zhao, Z and Ellis, MS and Nie, Z and Liu, QH},
Title = {Printed double-dipole antenna with high directivity using a
new feeding structure},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {8},
Number = {14},
Pages = {1186-1191},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2014},
Month = {May},
ISSN = {1751-8725},
url = {http://dx.doi.org/10.1049/iet-map.2014.0245},
Abstract = {In this study, a planar printed double-dipole antenna with
broadband performance and high directivity is presented. The
proposed antenna consists of two dipole elements, two pairs
of parallel striplines and a microstrip balun. The main
features of the designed antenna are the two dipole elements
designed with different lengths and excited in the left and
right parts with a pair of antiphase signals. The two dipole
elements are designed with different lengths for achieving
broadband performance. High directivity is obtained by
feeding the two dipole elements with the two antiphase
signals. In order to illustrate the effectiveness of the
proposed design, a prototype of the proposed antenna is
fabricated and measured. Experimental results of the
fabricated antenna have verified the effectiveness of the
proposed design. Measured results show that the fabricated
antenna provides a 53.7% impedance bandwidth ranging from
4.5 to 7.8 GHz and a measured gain better than 4 dBi. Good
unidirectional radiation patterns with a high front-to-back
ratio greater than 17 dB are achieved.},
Doi = {10.1049/iet-map.2014.0245},
Key = {fds283440}
}
@article{fds283473,
Author = {Ellis, MS and Zhao, Z and Wu, J and Nie, Z and Liu, QH},
Title = {Unidirectional planar monopole ultrawideband antenna using
wrench-shaped feeding structure},
Journal = {Electronics Letters},
Volume = {50},
Number = {9},
Pages = {654-655},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2014},
Month = {April},
ISSN = {0013-5194},
url = {http://dx.doi.org/10.1049/el.2014.0298},
Abstract = {A unidirectional planar monopole ultra-wideband (UWB)
antenna is presented. To realise unidirectional radiation, a
new feed structure is implemented without modifications in
the ground plane or the monopole. By using a wrench-shaped
feeding structure, unidirectional radiation of the planar
monopole antenna can be realised, especially at high
frequencies. The antenna is built on a 20 30 mm FR4
substrate to cover a frequency bandwidth from 3.1 to over 14
GHz for a voltage standing wave ratio ?2. © The Institution
of Engineering and Technology 2014.},
Doi = {10.1049/el.2014.0298},
Key = {fds283473}
}
@article{fds283498,
Author = {Tobón, LE and Ren, Q and Liu, QH},
Title = {Spectral-prism element for multi-scale layered package-chip
co-simulations using the discontinuous galerkin time-domain
method},
Journal = {Electromagnetics},
Volume = {34},
Number = {3-4},
Pages = {270-285},
Publisher = {Informa UK Limited},
Year = {2014},
Month = {April},
ISSN = {0272-6343},
url = {http://dx.doi.org/10.1080/02726343.2014.877766},
Abstract = {A new kind of prism element with a triangular base is
presented for discretization of multi-scale layered
structures within the discontinuous Galerkin time-domain
framework. Mixed-order curl-conforming vector basis
functions are used in the triangular bases of the prismatic
element. The height of the prism adopts spectral basis
functions based on Gauss-Lobatto-Legendre polynomials, with
an arbitrary order of interpolation. This method combines
the flexibility of triangles with the accuracy of spectral
elements for layered structures. Eigenvalues obtained show
better results than traditional finite elements using
tetrahedrons and hexahedrons. For transient analysis, the
implicit Crank-Nicholson method is implemented for
sequential sub-domains. This kind of arrangement of
sub-domains produces a block tridiagonal linear system, thus
allowing a block Thomas algorithm to solve the system
efficiently. A package-to-chip example shows the efficacy of
this method. © Taylor and Francis.},
Doi = {10.1080/02726343.2014.877766},
Key = {fds283498}
}
@article{fds283405,
Author = {Lei, S and Zhao, Z and Nie, Z and Liu, QH},
Title = {Fast optimization method of polarization receiving power for
monostatic condition based on Kennaugh matrix},
Journal = {2014 Ieee International Conference on Communication Problem
Solving, Iccp 2014},
Pages = {376-379},
Publisher = {IEEE},
Year = {2014},
Month = {March},
ISBN = {9781479942466},
url = {http://dx.doi.org/10.1109/ICCPS.2014.7062298},
Abstract = {Different polarization incidences and/or inflections yield
different polarization scattering powers. The problem of
searching optimal polarization state for the maximal
polarization receiving power (PRP) is of significantly
meaningful. Usually, there are no analytic solutions to the
problem and current numerical methods are time consuming.
Aiming to reduce the computational time, fast optimization
mechanism is studied in this paper. An improved Lagrange
method (ILM) based on bisection strategy is proposed for
monostatic condition. This method takes the advantage of
monotonicity of a cost function constructed by Lagrange
multiplier to accelerate searching speed. The performance of
this method is validated by comparing with the Lagrange
method proposed by Chen (LMC). Numerical experiments
demonstrate that the proposed method in this paper is
superior to the existing method.},
Doi = {10.1109/ICCPS.2014.7062298},
Key = {fds283405}
}
@article{fds283471,
Author = {Feng, N and Yue, Y and Zhu, C and Liu, QH and Wan, L},
Title = {Efficient Z-transform implementation of the D-B CFS-PML for
truncating multi-term dispersive FDTD domains},
Journal = {Applied Computational Electromagnetics Society
Journal},
Volume = {29},
Number = {3},
Pages = {190-196},
Year = {2014},
Month = {March},
ISSN = {1054-4887},
Abstract = {Efficient Z-transform implementation of the Complex
Frequency-Shifted Perfectly Matched Layer (CFS-PML) using
the D-B formulations are proposed to truncate open region
multi-term dispersive Finite-Difference Time-Domain (FDTD)
lattices. These formulations are independent of material
properties of the FDTD domains and hence can be used for
modeling general media because of the D-B constitutive
relations. A Three-Dimensional (3-D) simulation of the
two-term Lorentz dispersive FDTD domain has been carried out
to demonstrate the validity of the proposed formulations.
Furthermore, in order to show the validity of the proposed
algorithm, the second 3D inhomogeneous problem has also been
used for validating the proposed formulations. It is clearly
shown that the new formulations with the CFS-PML scheme are
efficient in attenuating evanescent waves and reducing
late-time reflections.},
Key = {fds283471}
}
@article{fds283526,
Author = {Liu, Y and Liu, QH},
Title = {Combining triangle Gaussian integration and modified NUFFT
for evaluating two-dimensional Fourier transform
integrals},
Journal = {Aeu International Journal of Electronics and
Communications},
Volume = {68},
Number = {3},
Pages = {254-259},
Year = {2014},
Month = {March},
ISSN = {1434-8411},
url = {http://dx.doi.org/10.1016/j.aeue.2013.09.007},
Abstract = {The regular fast Fourier transform (FFT) requires a uniform
Cartesian orthogonal grid which has considerable
stair-casing errors when dealing with the function having an
arbitrary shape boundary. The recently proposed
two-dimensional discontinuous fast Fourier transform
(2D-DFFT) can overcome this problem by using triangle mesh
discretization and Gaussian numerical integration. However,
the interpolation is used for the function data in the
original 2D-DFFT, which reduces the accuracy performance
especially for the case of oscillating functions. This work
presents a useful modification of the original 2D-DFFT by
removing the requirement of function interpolation to obtain
significant accuracy improvement. In addition, the modified
2D nonuniform fast Fourier transform (NUFFT) with
real-valued least-square interpolation coefficients are
developed to speed up the computation of numerical Fourier
transform over the triangle mesh. Numerical experiments are
conducted to demonstrate the effectiveness and advantages of
the proposed algorithms. © 2013 Elsevier GmbH. All rights
reserved.},
Doi = {10.1016/j.aeue.2013.09.007},
Key = {fds283526}
}
@article{fds283527,
Author = {Xu, KD and Zhang, YH and Fan, Y and Li, JLW and Joines, WT and Liu,
QH},
Title = {Planar dual- and tri-band bandpass filters using single
improved ring resonator and simple feed scheme},
Journal = {Microwave and Optical Technology Letters},
Volume = {56},
Number = {3},
Pages = {574-577},
Publisher = {WILEY},
Year = {2014},
Month = {March},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.28159},
Abstract = {A planar single improved dual-mode ring resonator loaded by
four mushroom-shaped stubs based on a simple feed scheme is
presented for design of dual- and tri-band bandpass filters
(BPFs). The simple pair of feed lines with source-load
coupling is used to not only feed the ring resonator but
also generate the higher desired third passband when the
length of feed lines changes. That is, a desired dual- or
tri-band BPF can be designed based on the same single-ring
resonator. For demonstration purpose, two experimental
example filters have been fabricated and implemented. The
simulated and measured results are presented and show good
agreements. © 2014 Wiley Periodicals, Inc.},
Doi = {10.1002/mop.28159},
Key = {fds283527}
}
@article{fds283522,
Author = {Liu, X and Chen, XY and Lin, Y and Ye, LF and Xiao, F and Liu,
QH},
Title = {A coaxial measurement system for electromagnetic parameters
at microwave frequencies},
Journal = {Advanced Materials Research},
Volume = {881-883},
Pages = {1832-1835},
Publisher = {Trans Tech Publications},
Year = {2014},
Month = {February},
url = {http://dx.doi.org/10.4028/www.scientific.net/AMR.881-883.1832},
Abstract = {In this paper, an improved coaxial measurement system with a
newly designed coaxial fixture is presented. The
electromagnetic parameters of samples are retrieved from the
scattering parameters measured by avector network analyzer
(VNA) at microwave frequencies. The measurements of air and
PTFE in the range of 1~6GHz were carried out to verify the
reliability and the accuracy of this measurement system. By
using frequency-sweep and data processing techniques, the
multiplicity of roots is eliminated. The results show that
this system can effectively be applied to measure the
material electromagnetic parameters of absorbing materials
with high accuracy in a wide frequency band. © (2014) Trans
Tech Publications, Switzerland.},
Doi = {10.4028/www.scientific.net/AMR.881-883.1832},
Key = {fds283522}
}
@article{fds283525,
Author = {Chen, XY and Liu, X and Ye, LF and Li, XY and Xiao, F and Liu,
QH},
Title = {An electromagnetic parameters measuring system based on a
concave cylindrical cavity},
Journal = {Advanced Materials Research},
Volume = {881-883},
Pages = {1754-1757},
Publisher = {Trans Tech Publications},
Year = {2014},
Month = {February},
url = {http://dx.doi.org/10.4028/www.scientific.net/AMR.881-883.1754},
Abstract = {In this paper, an electromagnetic parameters measuring
system based on a concave cylindrical cavity is presented.
The concave cylindrical cavity resonator mode is TM010 with
separated electric field and magnetic field distribution
region, which is not observed in other cavities. It is shown
that permittivity and permeability can be tested by placing
samples in the strongest electric field region and magnetic
field region, respectively. Therefore, by using this
measurement system, the electromagnetic parameters of
microwave absorbing materials can be accurately
characterized. © (2014) Trans Tech Publications,
Switzerland.},
Doi = {10.4028/www.scientific.net/AMR.881-883.1754},
Key = {fds283525}
}
@article{fds283380,
Author = {Wang, J and Zhao, Z and Lei, S and Song, J and Liu, QH},
Title = {A new time-of-flight (TOF) picker for tumor tissue in
microwave induced thermo-acoustic tomography (MITAT)
system},
Journal = {International Conference on Signal Processing Proceedings,
Icsp},
Volume = {2015-January},
Number = {October},
Pages = {1805-1810},
Publisher = {IEEE},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1109/ICOSP.2014.7015305},
Abstract = {In this paper, a new method for accurately picking the
time-of-flights (TOFs) of tumor is proposed in microwave
induced thermo-acoustic tomography (MITAT) system. The
proposed method makes use of the properties of induced
thermal acoustic signal and combines them with the wavelet
transform and Akaike information criterion (AIC). Both
numerical simulations and ex vivo experimental results are
given to test the performance of the proposed method.
Through the simulations and experiment, the proposed method
can efficiently and accurately pick the TOFs of tumor target
in MITAT system and therefore provide a guarantee for
imaging tumor with high accuracy.},
Doi = {10.1109/ICOSP.2014.7015305},
Key = {fds283380}
}
@article{fds283381,
Author = {Lei, S and Zhao, Z and Nie, Z and Liu, QH},
Title = {An adaptive detector for detecting target in clutter plus
Gaussian noise background},
Journal = {International Conference on Signal Processing Proceedings,
Icsp},
Volume = {2015-January},
Number = {October},
Pages = {1919-1924},
Publisher = {IEEE},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1109/ICOSP.2014.7015327},
Abstract = {In this paper, the problem of target detection in the
clutter plus Gaussian noise background is considered. The
published detectors group the clutter and the noise as a
single parameter; differently, we deal separately with the
clutter and the noise. In the paper, the noise is assumed to
be obtained in advance and the clutter is distributed
according to a certain distribution. An adaptive target
detector which utilizes the maximum likelihood estimate
(MLE) of the clutter covariance and the MLE of the signal of
interest (SOI) is proposed. The detector has a simpler
expression than the published detectors. To validate its
detection performance, the proposed detector is compared
with three published detectors. Numerical experimental
results demonstrate that the proposed detector has better
detection performance; moreover, the proposed detector can
obtain reliable detection performance with less secondary
data.},
Doi = {10.1109/ICOSP.2014.7015327},
Key = {fds283381}
}
@article{fds283383,
Author = {Wang, J and Zhao, Z and Song, J and Zhu, X and Liu, QH},
Title = {A comparison of three imaging algorithms on reconstructing
tumor target in acoustic heterogeneous tissue with realistic
numerical breast phantoms in microwave induced
thermo-acoustic tomography},
Journal = {International Conference on Signal Processing Proceedings,
Icsp},
Volume = {2015-January},
Number = {October},
Pages = {1083-1089},
Publisher = {IEEE},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1109/ICOSP.2014.7015170},
Abstract = {Accurately reconstruct the tumor target in an acoustic
heterogeneous tissue is a hot research issue in
thermo-acoustic tomography (TAT). In this paper, we present
three imaging algorithms for microwave induced
thermo-acoustic tomography (MITAT): time reversal mirror
(TRM), active adjoint modeling (AAM) method and iterative
reconstruction method (IRM). The performance of the three
imaging methods for reconstructing tumor target in
heterogeneous breast tissue are verified and compared by
using the anatomically realistic numerical breast phantoms
derived from T1-weighted MRIs of prone patients. Through the
simulation results, the IRM proves to have better imaging
results than TRM and consume much less computing time than
AAM. The IRM is a promising approach for imaging tumor
target in heterogeneous breast tissue in
TAT.},
Doi = {10.1109/ICOSP.2014.7015170},
Key = {fds283383}
}
@article{fds283436,
Author = {Wang, JG and Zhao, ZQ and Nie, ZP and Liu, QH},
Title = {Subsurface imaging 3-D objects in multilayered media by
using electromagnetic inverse scattering series method
(EISSM)},
Journal = {Progress in Electromagnetics Research Symposium},
Pages = {1041-1045},
Year = {2014},
Month = {January},
ISBN = {9781934142288},
ISSN = {1559-9450},
Abstract = {Subsurface imaging 3-D objects buried in layered medium with
electromagnetic waves has recently attracted significant
interests. Due to the uncertainty of dielectric parameters
of layered background media in practice, most of existing
electromagnetic inverse methods reconstruct the buried
objects unfaithfully. In order to accurately reconstruct the
objects buried in multilayered media with unknown dielectric
parameters, we develop a new imaging method named
electromagnetic inverse scattering series method (EISSM) for
imaging 3-D objects in multilayered media. The 3-D EISSM
combines the inverse scattering series (ISS) theory with a
multi-array tomographic approach. It directly reconstructs
the positions of the buried objects (not their dielectric
properties) solely with the dielectric parameters of free
space according to the discontinuities of dielectric
parameters. Moreover, the effects of multilayered media to
the position error predicted by EISSM are also analyzed and
discussed. Aiming to validate the feasibility of the
developed 3-D EISSM, some numerical simulations are given as
well as the results reconstructed by commonly used time
reversal mirror (TRM) technique. Through the simulations,
the EISSM is capable of positioning 3-D targets buried in
multilayered media with less error than traditional
TRM.},
Key = {fds283436}
}
@article{fds283437,
Author = {Lei, S and Zhao, Z and Nie, Z and Liu, QH},
Title = {Adaptive optimal polarization detection of target in clutter
background based on generalized Rayleigh
quotient},
Journal = {Progress in Electromagnetics Research Symposium},
Pages = {234-238},
Year = {2014},
Month = {January},
ISBN = {9781934142288},
ISSN = {1559-9450},
Abstract = {Most current methods on polarization targets detection
assume the target echoes to be ascertained in signal model
during the detection period. But in fact, the target echo
may obey a kind of distribution and the distribution relates
with the polarizations. Aiming at improving the performance
of polarization detection, an adaptive generalized
likelihood ratio (AGLR) polarization detector is proposed.
The detector assumes the target echo to be a non-zero mean
Gaussian distribution with respect to the polarization
states of transceiver. It adaptively adjusts the
polarization states of transceiver according to the
variation of the polarization characteristics of target and
clutter to maximize signal to clutter and noise ratio
(SCNR). The problem of maximizing the SCNR is converted to a
problem of maximizing a generalized Rayleigh quotient (GRQ).
Based on the GRQ, the AGLR detector is proposed. The
performance of the AGLR detector is theoretically analyzed
and numerically validated through some numerical
experiments. Compared with two conventional GLR detectors,
the AGLR detector achieves a 3 dB to 10 dB
improvement.},
Key = {fds283437}
}
@article{fds283438,
Author = {Feng, N and Yue, Y and Zhu, C and Liu, QH},
Title = {Effective implementation of the CFS-PML using DSP techniques
for truncating dispersive medium FDTD domains},
Journal = {Progress in Electromagnetics Research Symposium},
Pages = {1127-1130},
Year = {2014},
Month = {January},
ISBN = {9781934142288},
ISSN = {1559-9450},
Abstract = {Efficient and unsplit-field finite-difference time-domain
(FDTD) implementation of the complex frequency-shifted
perfectly matched layer (CFS-PML), based on the digital
signal processing (DSP) techniques and the material
independence relations via applying the electric flux
density (D) and the magnetic flux density (B), is proposed
for truncating three dimensional FDTD computational domain
entirely composed of dispersive material realized with a
Drude model. The CFS-PML implementation is introduced based
on the stretched coordinate PML (SC-PML) and the uniaxial
anisotropic PML (UPML), respectively. The implementation of
the proposed CFS-PML formulations is based on the SC-PML due
to the fact that has advantage of simple implementation in
the corners and the edges of the PML regions. Moreover,
these proposed formulations are completely independent of
the material properties of the FDTD computational domain and
hence can be applied to truncate arbitrary media without any
modification because of the D-B constitutive relations used
in Maxwell's equations. Besides, the DSP techniques include
the Bilinear Z-transform (BZT) method and the Matched
Z-transform (MZT) method, respectively. However, from the
point of view of the Courant-Friedrichs-Levy (CFL)
condition, to the best of our knowledge, time step based on
the BZT only needs to meet CFL condition, whereas time step
based on the MZT method has to make it smaller for retaining
stability and desirable accuracy. Consequently, the former
one is introduced into the proposed formulations. A
numerical example has been carried out in a three
dimensional FDTD computational domain to validate the
proposed formulations. It is clearly shown that the proposed
formulations with CFS scheme are efficient in attenuating
evanescent waves and reducing late-time reflections.},
Key = {fds283438}
}
@article{fds283439,
Author = {Xu, K and Spiegel, RJ and Zhang, Y and Joines, WT and Liu,
QH},
Title = {Patch antenna with electrically tunable ferrite-ferroelectric
bilayer},
Journal = {Progress in Electromagnetics Research Symposium},
Pages = {1772-1774},
Year = {2014},
Month = {January},
ISBN = {9781934142288},
ISSN = {1559-9450},
Abstract = {A coaxial-fed patch antenna with a ferrite-ferroelectric
bilayer above a regular alumina substrate has been designed
and analyzed. The ferrite-ferroelectric bilayer,
multiferroic heterostructure, consists of a
near-single-crystal ferrite yttrium iron garnet (YIG) film
layer and a ferroelectric ceramic barium strontium titanate
(BST) film layer with thicknesses of 1 μm and 0.5 μm,
respectively. When the electric field applied across the BST
layer changes from 2.5 V/um to 15 V/um, its permittivity
will be tuned, thus the operating frequency of the antenna
will shift as well. We also analyze the influence of the
static magnetic field variation to the operating frequency
of the antenna.},
Key = {fds283439}
}
@article{fds283448,
Author = {Wang, B and Zhao, Z and Zhu, X and Song, J and Wang, J and Nie, Z and Liu,
QH},
Title = {Hierarchical dictionary compressive sensing (HDCS) method in
microwave induced thermal acoustic tomography},
Journal = {Biomedical Signal Processing and Control},
Volume = {14},
Number = {1},
Pages = {148-157},
Publisher = {Elsevier BV},
Year = {2014},
Month = {January},
ISSN = {1746-8094},
url = {http://dx.doi.org/10.1016/j.bspc.2014.07.012},
Abstract = {Aiming to reduce the reconstruction time and enhance the
image quality of microwave induced thermal acoustic
tomography (MITAT), a new image reconstruction method named
HDCS-MITAT (HDCS: hierarchical dictionary compressive
sensing) is proposed. Different from the recently
demonstrated CS-MITAT (CS: compressive sensing) imaging
method in which only one level dictionary is applied,
hierarchical dictionaries are used in the HDCS-MITAT. In
this method, the dictionaries with different spatial
resolutions are constructed which constitute a hierarchical
structure. During the image reconstructions, first the
coarsest level dictionary is utilized to roughly estimate
the position of the targets in the original image domain. A
reduced interested image domain can be set based on this
estimation. Then the next level dictionary which has higher
resolution than the above level is applied to further
estimating the position of the targets and so on. Finally,
the finest level dictionary is used to reconstruct the image
of the targets. Compared with the CS-MITAT, this HDCS-MITAT
has much less computational time and better image quality.
The effectiveness of the method has been validated through
some simulations and real breast tumor experiments. © 2014
Elsevier Ltd.},
Doi = {10.1016/j.bspc.2014.07.012},
Key = {fds283448}
}
@article{fds283457,
Author = {Jiang, W and Liu, N and Tang, Y and Liu, QH},
Title = {Mixed finite element method for 2D vector Maxwell's
eigenvalue problem in anisotropic media},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {148},
Pages = {159-170},
Publisher = {EMW Publishing},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.2528/PIER14052608},
Abstract = {It is well known that the conventional edge element method
in solving vector Maxwell's eigenvalue problem will lead to
the presence of nonphysical zero eigenvalues. This paper
uses the mixed finite element method to suppress the
presence of these nonphysical zero eigenvalues for 2D vector
Maxwell's eigenvalue problem in anisotropic media. We
introduce a Lagrangian multiplier to deal with the
constraint of divergence-free condition. Our method is based
on employing the first-order edge element basis functions to
expand the electric field and linear nodal element basis
functions to expand the Lagrangian multiplier. Our numerical
experiments show that this method can successfully remove
all nonphysical zero and nonzero eigenvalues. We verify that
when the cavity has a connected perfect electric boundary,
then there is no physical zero eigenvalue. Otherwise, the
number of physical zero eigenvalues is one less than the
number of disconnected perfect electric boundaries.},
Doi = {10.2528/PIER14052608},
Key = {fds283457}
}
@article{fds283458,
Author = {Ellis, MS and Zhao, ZQ and Wu, JN and Nie, ZP and Liu,
QH},
Title = {A new compact microstrip-fed monopole antenna for triple
band WLAN/WiMAX applications},
Journal = {Progress in Electromagnetics Research Letters},
Volume = {48},
Pages = {129-135},
Publisher = {EMW Publishing},
Year = {2014},
Month = {January},
ISSN = {1937-6480},
url = {http://dx.doi.org/10.2528/PIERL14061004},
Abstract = {A new compact printed tri-band antenna for WLAN/WiMAX
applications is presented. The proposed antenna consists of
three inverted L-shaped strips whose geometry looks like a
“bent fork”. These strips are attached to the feed line
through a horizontal strip. By optimizing the geometries of
the inverted L-shaped strips, distinct resonant points can
be effectively created for different frequency bands. The
overall size of the proposed antenna is 18 × 33 mm2.
Simulated and measured results show that the presented
antenna can cover 2.5/3.5/5.5 WLAN and WIMAX bands with
fairly stable radiation.},
Doi = {10.2528/PIERL14061004},
Key = {fds283458}
}
@article{fds283460,
Author = {Wang, J and Zhao, Z and Lei, S and Liu, J and Liu, QH},
Title = {Effects of frequency information to the electromagnetic
inverse scattering series method (EISSM)},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {233-238},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISBN = {9781479920341},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875590},
Abstract = {For subsurface sensing objects using electromagnetic waves,
most of current imaging methods need priori information of
exact dielectric properties of background media in order to
accurately reconstruct the concealed targets. This condition
is hardly satisfied in practice. Recently, an efficiently
qualitative imaging method termed electromagnetic inverse
scattering series method (EISSM) is developed to image the
buried targets. EISSM reconstructs concealed targets in the
layered media by only utilizing dielectric properties of
free space. However, the effects of frequency information to
the EISSM have never been discussed. In this paper, we
analyze and discuss the effects of frequency information to
the performance of EISSM when imaging the buried objects.
Through some numerical simulations, EISSM can obtain
favorable image results with a broad frequency spectrum of
measured data. © 2014 IEEE.},
Doi = {10.1109/RADAR.2014.6875590},
Key = {fds283460}
}
@article{fds283461,
Author = {Li, N and Cui, G and Kong, L and Zhang, T and Liu, QH},
Title = {Wald test designed for moving target with MIMO radar in
compound-Gaussian clutter},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {185-189},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875581},
Abstract = {We present the problem of moving target detection with
multiple-input multiple-output (MIMO) radar in
compound-Gaussian clutter. A new moving target detector
based on the Wald criterion is devised according to the
centralized processing scheme of MIMO radar system.
Furthermore, the adaptive version of the proposed detector
is investigated by in place of the exact covariance matrix
with the fixed point estimation (FPE) using secondary data.
Finally, several numerical simulations with typical
parameters are provided and discussed. © 2014
IEEE.},
Doi = {10.1109/RADAR.2014.6875581},
Key = {fds283461}
}
@article{fds283462,
Author = {Yang, H and Li, T and He, Z and Liu, QH},
Title = {Radio frequency interference suppression in cross-borehole
impulse radar for well logging},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {395-399},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875622},
Abstract = {In this paper, the problem of radio frequency interference
caused by leak energy from signal source in cross-borehole
impulse radar is presented. These interferences reduce the
focused image quality. A method based on the frequency
difference between signal and clutter is put forward to
improve signal-to-noise-ratio and the corresponding infinite
impulse response band-pass filter is designed before the
delay-and-sum processing. It is proved with field data that
the filter improves the image result and makes the signal
energy more focused. © 2014 IEEE.},
Doi = {10.1109/RADAR.2014.6875622},
Key = {fds283462}
}
@article{fds283463,
Author = {Li, N and Cui, G and Kong, L and Zhang, T and Liu, QH},
Title = {Moving target detection for polarimetric MIMO radar in
homogeneous Gaussian clutter},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {154-158},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875575},
Abstract = {This paper considers the moving target detection (MTD)
problem for polarimetric multiple-input multiple-output
(MIMO) radar in the presence of Gaussian clutter. By
exploiting the polarimetric information, we devise two
different generalized likelihood ratio tests (GLRTs) with a
generic number of polarimetric channels, according to the
centralized and distributed processing schemes of MIMO radar
systems, respectively. Then, we provide several numerical
simulations with typical parameters, and the results
illustrate that the use of multiple polarimetric channels
can yield a reasonable improvement in the detection of
moving target. © 2014 IEEE.},
Doi = {10.1109/RADAR.2014.6875575},
Key = {fds283463}
}
@article{fds283464,
Author = {Li, N and Cui, G and Kong, L and Zhang, T and Liu, QH},
Title = {MIMO radar moving target detection in compound-Gaussian
clutter},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {149-153},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875574},
Abstract = {This paper considers moving target detection for
multiple-input multiple-output (MIMO) radar in
compound-Gaussian clutter. A new detector is devised
according to a centralized processing scheme for MIMO radar
system based on the generalized likelihood ratio test (GLRT)
design criterion. Then, an adaptive version of the derived
detector is investigated. The fixed point estimation (FPE)
strategy is introduced to make the proposed detector fully
adaptive. Finally, several numerical simulations of the
derived detectors with typical parameters are obtained and
discussed. © 2014 IEEE.},
Doi = {10.1109/RADAR.2014.6875574},
Key = {fds283464}
}
@article{fds283466,
Author = {Liu, J and Zhao, Z and Wang, J and Liu, QH},
Title = {A robust sparse optimization for pattern synthesis with
unknown manifold error},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {99-103},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875563},
Abstract = {The performance of synthesis pattern with sparse arrays is
known to degrade in the presence of errors in the array
manifolds. This paper introduces a beampattern synthesis
approach with uncertain manifold vectors perturbation for
linear array. In order to match the desired pattern and
minimize the elements simultaneously, the convex
optimization of minimizing a reweighted l 1-norm objective
based on the weights of elements is proposed. The
superposition sampling is used for select the elements. The
excitation weights and sensor positions of an array
radiating pencil beampatterns are obtained. This method is
demonstrated through numerical simulations. The results show
the maximally sparse array in beampattern synthesis with
manifold vectors perturbation is obtained and the method is
effective. © 2014 IEEE.},
Doi = {10.1109/RADAR.2014.6875563},
Key = {fds283466}
}
@article{fds283467,
Author = {Yang, H and Li, T and He, Z and Liu, QH},
Title = {A compressive sensing data acquisition and imaging method
for impulse borehole radar},
Journal = {Ieee National Radar Conference Proceedings},
Pages = {139-143},
Publisher = {IEEE},
Year = {2014},
Month = {January},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2014.6875572},
Abstract = {In this paper, a novel data acquisition and imaging method
based on compressive sensing (CS) is utilized for impulse
borehole radar (IBR). With the sparse transform we present
for the IBR systems, only 50% or even less samples are
demanded to be collected and transmitted to reconstruct the
target space. It reduces the required sampling rate and data
transmission rate of IBR systems. Moreover, the simulation
and experiment results show that the target spaces
reconstructed by CS-based imaging method are less cluttered,
comparing with the solutions of traditional Stolt migration
method. © 2014 IEEE.},
Doi = {10.1109/RADAR.2014.6875572},
Key = {fds283467}
}
@article{fds283472,
Author = {Ellis, MS and Zhao, ZQ and Wu, JN and Ma, K and Nie, ZP and Liu,
QH},
Title = {A planar monopole UWB antenna with improved lower end
bandwidth using an L-shaped stub extended on the ground
plane},
Journal = {Progress in Electromagnetics Research C},
Volume = {52},
Pages = {109-114},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.2528/PIERC14052001},
Abstract = {In this work, a planar monopole ultra-wideband (UWB) antenna
with an L-shaped stub on the ground plane is proposed. The
novel extended L-stub in conjunction with the UWB radiator
achieves an ultra wideband impedance matching with a compact
size. The proposed antenna is fabricated and measured
showing an ultra wide operating frequency range from 2.3 to
over 14 GHz (VSWR < 2) with a unidirectional gain from 3-6.5
dBi and efficiency from 70-85% within the UWB band from
3.1-10.6 GHz. The proposed antenna provides a new way to
improve ultra wideband impedance matching other than the
frequently used tapered microstrip feed line. It also
provides a way to improve the lower frequency bandwidth of
the antenna without increasing the antenna's physical size,
which is the most common method to use.},
Doi = {10.2528/PIERC14052001},
Key = {fds283472}
}
@article{fds283480,
Author = {Xu, KD and Zhang, YH and Li, JLW and Joines, WT and Liu,
QH},
Title = {Compact ultra-wideband bandpass filter using
quad-T-stub-loaded ring structure},
Journal = {Microwave and Optical Technology Letters},
Volume = {56},
Number = {9},
Pages = {1988-1991},
Publisher = {WILEY},
Year = {2014},
Month = {January},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.28508},
Abstract = {A compact ultrawideband (UWB) planar bandpass filter (BPF)
using quad-T-stub-loaded ring resonator is presented. At
this filter, two sets of the four high impedance lines at
the two sides of the ring as the coupling fed structure are
used to gain much stronger coupling effect. Compared with
the conventional ring resonator filter, the bandwidth of the
UWB BPF can be improved after we load four T-shaped stubs on
the ring resonator. That is because these stubs can increase
the effective electrical lengths, and also lower the second
and third resonant frequencies of the ring resonator at no
expense of the size increase. Finally, a prototype of the
proposed UWB BPF with 3 dB fractional bandwidth of 101% has
been designed and fabricated. The measured results are in
good agreement with the full-wave simulations. © 2014 Wiley
Periodicals, Inc.},
Doi = {10.1002/mop.28508},
Key = {fds283480}
}
@article{fds283481,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {Design of a wideband planar printed quasi-yagi antenna using
stepped connection structure},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {62},
Number = {6},
Pages = {3431-3435},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2014.2314471},
Abstract = {Although conventional Yagi antenna has the advantage of
unidirectional radiation patterns, it is not suitable for
wideband applications due to its drawback of narrow
bandwidth. In this communication, a compact wideband planar
printed quasi-Yagi antenna is presented. The proposed
quasi-Yagi antenna consists of a microstrip line to slotline
transition structure, a driver dipole, and a parasitic strip
element. The driver dipole is connected to the slotline
through a coplanar stripline (CPS). The proposed antenna
uses a stepped connection structure between the CPS and the
slotline to improve the impedance matching. Two apertures
are symmetrically etched in the ground plane to improve the
unidirectional radiation characteristics. Simulation and
experimental results show that the unidirectional radiation
patterns of the proposed antenna are good. A 92.2% measured
bandwidth with S11 < -10 dB from 3.8 to 10.3 GHz is
achieved. A moderate gain, which is better than 4 dBi, is
also obtained. © 2014 IEEE.},
Doi = {10.1109/TAP.2014.2314471},
Key = {fds283481}
}
@article{fds283482,
Author = {Wu, J and Zhao, Z and Ellis, MS and Nie, Z and Liu, QH},
Title = {Enhanced directivity and bandwidth of a stepped open-slot
antenna with L-shaped slots and parasitic
strip},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {8},
Number = {7},
Pages = {465-473},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2014},
Month = {January},
ISSN = {1751-8725},
url = {http://dx.doi.org/10.1049/iet-map.2013.0304},
Abstract = {In this study, a printed stepped open-slot antenna with
unidirectional radiation characteristics is presented. Using
a stepped feeding slot and a parasitic metal strip, the
impedance matching is improved and a wide bandwidth is
achieved. Additionally, by modifying the ground plane with a
pair of L-shaped slots, the radiation directivity of the
proposed antenna is significantly enhanced and good
unidirectional radiation characteristics are obtained. To
demonstrate the effectiveness of the design, a prototype
antenna is fabricated and tested. Experimental results show
that the antenna provides a fractional bandwidth of 101%,
ranging from 3.65 to 11.1 GHz with a compact size (30 mm ×
30 mm). A moderate gain, which is better than 4 dBi, is also
obtained. In addition, a stable radiation directivity, which
is fixed in the endfire direction (y-axis direction) is
achieved. The measured front-to-back ratio is larger than
9.5 dB within the effective bandwidth. © The Institution of
Engineering and Technology 2014.},
Doi = {10.1049/iet-map.2013.0304},
Key = {fds283482}
}
@article{fds283483,
Author = {Xu, KD and Zhang, YH and Wang, L and Yuan, MQ and Fan, Y and Joines, WT and Liu, QH},
Title = {Two memristor SPICE models and their applications in
microwave devices},
Journal = {Ieee Transactions on Nanotechnology},
Volume = {13},
Number = {3},
Pages = {607-616},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {1536-125X},
url = {http://dx.doi.org/10.1109/TNANO.2014.2314126},
Abstract = {This paper presents two simple SPICE circuit models of the
memristor using two different kinds of integrators. These
models expand and simplify the previous methods of solving
the memristor's modeling equations presented by
Hewlett-Packard Lab. The behaviors of the two memristor
models are investigated when they are excited by a
sinusoidal voltage source. Both models satisfy the general
features of memristive systems such as having a
zero-crossing property in the form of an i-v Lissajous
figure. In order to explore the unique characteristics and
applications of the memristor in microwave devices, first we
incorporate the memristor in a microstrip transmission line
as a load. We do the analysis using a finite-difference
time-domain simulator integrated with a nonlinear SPICE
circuit solver. Furthermore, we design a reconfigurable
microstrip bandpass filter based on a memristor-loaded
resonator, and utilize a memristor as a carrier-wave
modulator connecting the microstrip patch antenna to the
ground. © 2002-2012 IEEE.},
Doi = {10.1109/TNANO.2014.2314126},
Key = {fds283483}
}
@article{fds283486,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {A compact printed dipole antenna for wideband wireless
applications},
Journal = {Progress in Electromagnetics Research C},
Volume = {50},
Pages = {95-102},
Publisher = {EMW Publishing},
Year = {2014},
Month = {January},
ISSN = {1937-8718},
url = {http://dx.doi.org/10.2528/PIERC14040207},
Abstract = {A compact printed dipole antenna with wide impedance
bandwidth is proposed in this paper. This antenna consists
of a pair of radiation metal arms and a microstrip-to-slotline
transition structure. At the end of the feeding slotted
line, a beveled slot with stepped connection structure is
designed to realize an offset feeding structure for feeding
the dipole antenna. By using the beveled offset feeding
structure, the bandwidth of the dipole antenna is
significantly improved. The microstrip-to-slotline
transition is used as an integrated balun to realize a
balanced feeding for the dipole antenna. To demonstrate the
effectiveness of the proposed design, a prototype of the
designed antenna is fabricated and measured. The measured
results show that the designed dipole antenna achieves a
gain of 2.2-4.4 dBi across a wide impedance bandwidth from
2.65 GHz to 17.5 GHz with a compact size (33 mm×16 mm). The
performance of the proposed dipole antenna is also compared
with some similar printed dipole antennas with respect to
overall size, substrate dielectric constant, impedance
bandwidth and antenna gain.},
Doi = {10.2528/PIERC14040207},
Key = {fds283486}
}
@article{fds283487,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {Design of anti-phase feeding network for W8JK Array based on
in-phase power divider},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {62},
Number = {5},
Pages = {2870-2873},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2014.2308548},
Abstract = {Double-dipole antennas driven by anti-phase signals (W8JK
array) are often used to achieve broadband and good
unidirectional radiation patterns. The two dipole elements
need a pair of anti-phase signals equal in magnitude.
However, realization of anti-phase signals with equal
magnitude for the W8JK array is difficult in a planar
structure. In this communication, an equivalent feed
mechanism of W8JK array is presented. An in-phase power
divider is used to realize an anti-phase feeding network for
feeding the W8JK array. In order to demonstrate the
effectiveness of the designed anti-phase feeding network, an
antenna prototype has been designed, fabricated and tested.
Experimental results show that the designed anti-phase
feeding structure for the W8JK array is effective. The
designed antenna provides a 64% measured bandwidth ranging
from 6.9 to 13.4 GHz. An excellent endfire radiation
characteristic with an F/B ratio better than 17 dB is
achieved. The measured gain is better than 4 dBi. © 2014
IEEE.},
Doi = {10.1109/TAP.2014.2308548},
Key = {fds283487}
}
@article{fds283488,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {A printed UWB vivaldi antenna using stepped connection
structure between slotline and tapered patches},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {13},
Pages = {698-701},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2014.2314739},
Abstract = {In this letter, a new stepped connection structure between
slotline and tapered patches is adopted in a planar printed
Vivaldi antenna. By using the stepped connection structure,
the impedance matching is significantly improved and a wide
bandwidth is achieved. In order to illustrate the
effectiveness of this design, a prototype of the modified
Vivaldi antenna is fabricated and tested. Experimental
results show that the impedance matching is significantly
improved in the band from 3 to 15.1 GHz. In addition, a
measured gain, which is better than 5 dBi, is obtained with
a compact size. Compared to other techniques, the presented
technique effectively improves the impedance matching and
enlarges the bandwidth without changing the overall
dimensions. Moreover, a relatively flat group time delay
response is achieved within the band of 3-15.1 GHz. ©
2002-2011 IEEE.},
Doi = {10.1109/LAWP.2014.2314739},
Key = {fds283488}
}
@article{fds283489,
Author = {Wu, J and Li, Z and Huang, Y and Yang, J and Liu, QH},
Title = {Omega-K imaging algorithm for one-stationary bistatic
SAR},
Journal = {Ieee Transactions on Aerospace and Electronic
Systems},
Volume = {50},
Number = {1},
Pages = {33-52},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0018-9251},
url = {http://dx.doi.org/10.1109/TAES.2013.120399},
Abstract = {In bistatic synthetic aperture radar (BSAR) with
one-stationary station, azimuth variation is a major
problem. In this paper, based on the two-dimensional (2D)
spatial linearization of the accurate analytical point
target reference spectrum, an Omega-K imaging algorithm to
deal with this problem is proposed. Different from the
traditional Omega-K algorithms for monostatic SAR and
translational invariant BSAR, the approach uses a 2D Stolt
frequency transformation. In addition, a compensation method
for the phase error caused by the linearization and the
related geometry registration are also discussed. Numerical
simulations verify the effectiveness of the proposed method.
© 2014 IEEE.},
Doi = {10.1109/TAES.2013.120399},
Key = {fds283489}
}
@article{fds283492,
Author = {Li, F and Liu, QH and Klemer, DP},
Title = {Plasmon resonance effects in GaAs/AlGaAs heterojunction
devices: An analysis based on spectral element
simulation},
Journal = {Ieee Transactions on Electron Devices},
Volume = {61},
Number = {5},
Pages = {1477-1482},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0018-9383},
url = {http://dx.doi.org/10.1109/TED.2014.2311473},
Abstract = {The effect of surface plasmons is investigated in III-V
devices that incorporate a subsurface heterojunction to
guide electron transport, in a structure analogous to that
of the high-electron mobility transistor. The use of the
spectral element method results in a highly efficient
computational approach; perturbations in the electric
potential resulting from surface plasmonic effects are
included in a self-consistent solution of the
Schrödinger-Poisson equations. The results of calculations
of electron conduction band edge and electron density
distribution are presented, and the effect of the plasmonic
penetration depth on electron density distribution in the
2-D electron gas at the heterojunction is studied. This
approach has broad applicability in the design and
simulation of III-V optoelectronic sensors and transducers
used for physiochemical and biological sensing and imaging.
© 1963-2012 IEEE.},
Doi = {10.1109/TED.2014.2311473},
Key = {fds283492}
}
@article{fds283494,
Author = {Zheng, J and Su, T and Zhang, L and Zhu, W and Liu, QH},
Title = {ISAR imaging of targets with complex motion based on the
chirp rate-quadratic chirp rate distribution},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {52},
Number = {11},
Pages = {7276-7289},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2014.2310474},
Abstract = {In inverse synthetic aperture radar (ISAR) imaging of
targets with complex motion such as fluctuating ships with
oceanic waves and high maneuvering airplanes, the azimuth
echo signals can be modeled as cubic phase signals (CPSs)
after the migration compensation. The chirp rate (CR) and
the quadratic chirp rate (QCR) are two important physical
quantities of the CPS, which deteriorate the azimuth
focusing quality due to the Doppler frequency shift. With
these two quantities, other parameters can be estimated by
using the fast Fourier transform (FFT). Therefore, the CPS
can be uniquely determined by both CR and QCR. In this
paper, based on the proposed generalized keystone transform
and the parametric instantaneous autocorrelation function, a
novel distribution of the CPS, known as the CR-QCR
distribution (CRQCRD), is presented and applied in a newly
proposed ISAR imaging algorithm for targets with complex
motion. The CRQCRD is simple and only requires the FFT and
the nonuniform FFT (NUFFT). Owing to the application of the
NUFFT, the computational cost is saved, and the searching
procedure is unnecessary for the nonuniformly spaced signal.
Compared to other four representative methods for CPSs, the
CRQCRD, which can acquire higher antinoise performance and
no error propagation, is searching-free and more suitable
for the situation of multitargets. Several simulation
examples, analyses of the antinoise performance, and ISAR
images validate the effectiveness of the CRQCRD and the
corresponding ISAR imaging algorithm. © 1980-2012
IEEE.},
Doi = {10.1109/TGRS.2014.2310474},
Key = {fds283494}
}
@article{fds283495,
Author = {Wu, J and Li, Z and Huang, Y and Yang, J and Liu, QH},
Title = {An omega-K algorithm for translational invariant bistatic
SAR based on generalized loffeld's bistatic
formula},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {52},
Number = {10},
Pages = {6699-6714},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2014.2301433},
Abstract = {In this paper, an omega-K imaging algorithm to focus the raw
data of translational invariant (TI) bistatic synthetic
aperture radar (BSAR) is proposed. The method utilizes a
point target reference spectrum of generalized Loffeld's
bistatic formula (GLBF). Without the bistatic deformation
term, GLBF is the latest development of Loffeld's bistatic
formula. It is comparable in precision with the method of
series reversion (MSR), but it has a much simpler form than
MSR and a similar form to a monostatic case. Based on the
spatial linearization of GLBF, the Stolt transformation
relationship is derived. The method can consider the linear
spatial variation of Doppler parameters, which is always
ignored in previous publications about bistatic omega-K
algorithms. This method can handle the cases of TI BSAR with
high squint angles and large bistatic degrees. In addition,
a compensation method for the phase error caused by the
linearization is discussed. Numerical simulations and
experimental data processing verify the effectiveness of the
proposed method. © 1980-2012 IEEE.},
Doi = {10.1109/TGRS.2014.2301433},
Key = {fds283495}
}
@article{fds283500,
Author = {Wu, J and Li, Z and Huang, Y and Yang, J and Liu, QH},
Title = {A generalized omega-K algorithm to process translationally
variant bistatic-SAR data based on two-dimensional stolt
mapping},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {52},
Number = {10},
Pages = {6597-6614},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2014.2299069},
Abstract = {In translationally variant (TV) bistatic synthetic aperture
radar (BSAR), 2-D spatial variation is a major problem to be
tackled. In this paper, a generalized Omega-K imaging
algorithm to deal with this problem is proposed. The method
utilizes a point target reference spectrum of the
generalized Loffeld's bistatic formula (LBF) (GLBF). Without
the bistatic-deformation term, GLBF is the latest
development of LBF. Similar to the monostatic case, it has a
much simpler form than other point target reference spectra.
Based on the spatial linearization of GLBF, the Stolt
mapping relationship is derived. Different from the
traditional Omega-K algorithms for monostatic SAR and
translationally invariant BSAR, this approach uses a 2-D
Stolt frequency transformation. Through this transformation,
the method can deal with the 2-D spatial variation. It can
also consider the linear spatial variation of Doppler
parameters, which is usually not considered in the previous
publications on bistatic Omega-K algorithms. This method can
handle the cases of TV-BSAR with different trajectories,
different velocities, high squint angles, and large bistatic
angles. In addition, a compensation method for the phase
error caused by the linearization is discussed. Numerical
simulations and experimental data processing verify the
effectiveness of the proposed method. © 1980-2012
IEEE.},
Doi = {10.1109/TGRS.2014.2299069},
Key = {fds283500}
}
@article{fds283520,
Author = {Liu, J and Zhao, Z and Yang, K and Liu, QH},
Title = {A hybrid optimization for pattern synthesis of large antenna
arrays},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {145},
Pages = {81-91},
Publisher = {EMW Publishing},
Year = {2014},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13121606},
Abstract = {The pattern synthesis for large antenna arrays has drawn
significant attention because of its wide applications. This
paper introduces a hybrid approach for the fast pencil beam
pattern synthesis of the large non-uniform linear or planar
array, which can significantly reduce the computational
cost, the number of antenna in the array, the minimum
sidelobe level and the null control. The proposed method has
an iterative scheme which is composed of the nonuniform
Fourier transform (NUFFT) and the global optimization method
to minimize the peak sidelobe level and control the null.
The NUFFT is utilized to determine excitation magnitudes for
a fixed positions non-uniform array. Alternatively, the
global optimization is used to find the optimal positions
which lead to the minimum peak sidelobe level (PSL). The
lower excitations can be deleted due to yielding less
performance on sidelobe level, which is called the array
removal strategy. Compare with conventional methods, the
simulations on synthetic models show that a minimum sidelobe
level and null control can be obtained in processing sparse
linear and concentric circular antenna arrays more
efficiently.},
Doi = {10.2528/PIER13121606},
Key = {fds283520}
}
@article{fds283521,
Author = {Zheng, J and Su, T and Zhu, W and Liu, QH},
Title = {ISAR imaging of targets with complex motions based on the
keystone time-chirp rate distribution},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {11},
Number = {7},
Pages = {1275-1279},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {1545-598X},
url = {http://dx.doi.org/10.1109/LGRS.2013.2291992},
Abstract = {In inverse synthetic aperture radar (ISAR) imaging of
targets with complex motions such as fluctuating ships with
oceanic waves and high maneuvering airplanes, the azimuth
echo signals can be modeled as cubic phase signals (CPSs).
In this letter, a new ISAR imaging algorithm based on the
keystone time-chirp rate distribution (KTCRD) is proposed
for the targets with complex motions. Compared with the
recently published algorithms for the CPSs, the KTCRD can
estimate the parameters of multicomponent CPSs without
searching procedures and can acquire high antinoise
performance with a relatively low computational load. With
the estimated motion parameters, high-quality ISAR images
can be obtained. Several simulation examples on the
synthetic model are shown to validate the effectiveness of
the new algorithm presented in this letter. © 2004-2012
IEEE.},
Doi = {10.1109/LGRS.2013.2291992},
Key = {fds283521}
}
@article{fds283524,
Author = {Liu, Y and Liu, QH and Nie, Z},
Title = {Reducing the number of elements in multiple-pattern linear
arrays by the extended matrix pencil methods},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {62},
Number = {2},
Pages = {652-660},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2013.2292529},
Abstract = {Previously, the matrix pencil method (MPM) and the
forward-backward MPM (FBMPM) were used to effectively reduce
the number of antenna elements in the single-pattern linear
arrays. This work extends the MPM and FBMPM-based synthesis
methods to the synthesis of multiple-pattern linear arrays
with a smaller number of elements. The extended MPM (resp.,
the extended FBMPM) method organizes all the multiple
pattern data into a composite Hankel (resp., composite
Hankel-Toeplitz) matrix from which the minimum number of
elements and the common poles corresponding to element
positions can be obtained with similar processing used in
the original MPM or FBMPM synthesis method. In particular,
the extended FBMPM inherits the advantage of the original
FBMPM that a useful restriction is put on the distribution
of poles, which makes the element positions obtained much
more accurate and robust. Numerical experiments are
conducted to validate the effectiveness and robustness of
the proposed methods. For the tested cases, the element
saving is about 20% ~ 25% for reconfigurable shaped
patterns, and can be even more for electrically large linear
arrays with scanned pencil-beams. © 1963-2012
IEEE.},
Doi = {10.1109/TAP.2013.2292529},
Key = {fds283524}
}
@article{fds283529,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {Bandwidth enhancement of a planar printed Quasi-Yagi antenna
with size reduction},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {62},
Number = {1},
Pages = {463-470},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2013.2287286},
Abstract = {A compact planar printed quasi-Yagi antenna is presented.
The proposed antenna consists of a microstrip line to
slotline transition structure, a driver dipole and two
parasitic strips. The driver dipole is connected to the
slotline through coplanar stripline (CPS). The ground plane
is modified by symmetrically adding two extended stubs to
reduce the lateral size. Experimental and simulated results
show that the proposed quasi-Yagi antenna has a wide
bandwidth and good unidirectional radiation characteristics.
Compared with conventional printed quasi-Yagi antennas, the
width of the proposed quasi-Yagi antenna is reduced by
approximately 16.7%. The proposed antenna presents an
excellent end-fire radiation with a front-to-back ratio
greater than 10 dB. Its measured bandwidth is from 3.6-11.6
GHz with a ratio of about 3.22: 1. A moderate gain, which is
better than 4 dBi, is obtained. © 1963-2012
IEEE.},
Doi = {10.1109/TAP.2013.2287286},
Key = {fds283529}
}
@article{fds283530,
Author = {Li, Z and Jin, T and Wu, J and Wang, J and Liu, QH},
Title = {Azimuth stacking algorithm for synthetic aperture radar
imaging},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {144},
Pages = {103-114},
Publisher = {EMW Publishing},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.2528/PIER13112203},
Abstract = {The aim of this paper is to present a frequency domain
method for synthetic aperture radar (SAR) imaging. By using
two consecutive linear mappings along Doppler and frequency
domains, an azimuth-dependent SAR transfer function has been
discovered. Based on this new transfer function, the SAR
image can be reconstructed by the proposed azimuth stacking
algorithm. The new algorithm can form SAR image at each
azimuth position without DFT wrap around errors. If Chirp
z-transform (CZT) is applied to carry out the two
consecutive mappings (since they are linear mappings), the
proposed algorithm will not require interpolations and thus
its reconstructed image would be free of truncation errors.
The new algorithm has been validated using both simulated
and experimental ultrawideband/widebeam (UWB/WB) SAR
data.},
Doi = {10.2528/PIER13112203},
Key = {fds283530}
}
@article{fds283532,
Author = {Yang, K and Zhao, Z and Liu, J and Huo Liu and Q},
Title = {Robust adaptive beamforming using an iterative FFT
algorithm},
Journal = {Signal Processing},
Volume = {96},
Number = {PART B},
Pages = {253-260},
Publisher = {Elsevier BV},
Year = {2014},
Month = {January},
ISSN = {0165-1684},
url = {http://dx.doi.org/10.1016/j.sigpro.2013.09.003},
Abstract = {Adaptive beamformers will degrade in the presence of model
mismatch. Because a wider beamwidth has higher ability
against steering vector errors, and lower sidelobe levels
can improve the robustness against fast moving
interferences, in this work an iterative fast Fourier
transform (FFT) based adaptive beamformer is proposed with
constraints on beamwidth and peak sidelobe level. The
adaptive beamforming is transformed to a weighted pattern
synthesis problem. This weighted pattern is a product of the
array pattern and a weighting function. Because the
weighting function has shape peaks at the direction of
interferences, it will have nulls in the array pattern at
the directions of interferences by reducing the peak
sidelobe level of this weighted pattern. A modified
iterative FFT algorithm is proposed to synthesize this
weighted pattern. Thanks to the efficiency of FFT, the
nonconvex problem of power pattern synthesis can be solved
efficiently. This method is demonstrated through several
simulation examples. The results show the advantages of the
proposed method in obtaining high output SINRs against
moving target signals and steering vector errors. © 2013
Elsevier B.V.},
Doi = {10.1016/j.sigpro.2013.09.003},
Key = {fds283532}
}
@article{fds283541,
Author = {Li, Z and Wang, J and Liu, QH},
Title = {Interpolation-free stolt mapping for SAR
imaging},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {11},
Number = {5},
Pages = {926-929},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {1545-598X},
url = {http://dx.doi.org/10.1109/LGRS.2013.2281847},
Abstract = {Interpolation-free Stolt mapping, based on Fourier transform
and phase multiplications, is proposed. Benefiting from this
method, an efficient wavenumber domain algorithm (E-ω-k)
can be achieved for generic synthetic aperture radar
imaging. The method is finally demonstrated using simulated
data. © 2013 IEEE.},
Doi = {10.1109/LGRS.2013.2281847},
Key = {fds283541}
}
@article{fds283560,
Author = {Wu, J and Li, Z and Huang, Y and Yang, J and Yang, H and Liu,
QH},
Title = {Focusing bistatic forward-looking SAR with stationary
transmitter based on keystone transform and nonlinear chirp
scaling},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {11},
Number = {1},
Pages = {148-152},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2014},
Month = {January},
ISSN = {1545-598X},
url = {http://dx.doi.org/10.1109/LGRS.2013.2250904},
Abstract = {With appropriate geometry configurations, bistatic synthetic
aperture radar (SAR) can break through the limitations of
monostatic SAR on forward-looking imaging. Thanks to such a
capability, bistatic forward-looking SAR (BFSAR) has
extensive potential applications, such as self-navigation
and self-landing. In the mode of BFSAR with a stationary
transmitter (ST-BFSAR), the two-dimensional spatial
variation makes it difficult to use traditional data
focusing algorithms. In this letter, an imaging algorithm
based on keystone transform and nonlinear chirp scaling
(NLCS) is proposed to deal with this problem. Keystone
transform is used to remove the spatial variation of range
cell migration. NLCS can eliminate the variation of azimuth
reference function. Numerical simulations show that by
combining first-order keystone transform and azimuth NLCS
operation, the raw data of ST-BFSAR can be well imaged. ©
2013 IEEE.},
Doi = {10.1109/LGRS.2013.2250904},
Key = {fds283560}
}
@article{fds341217,
Author = {Li, J and Jia, Y and He, Z and Liu, QH},
Title = {A fast solver for vertical electromagnetic profiles of
surface to borehole electromagnetic method
(SBEM)},
Journal = {Seg Technical Program Expanded Abstracts},
Volume = {33},
Pages = {628-632},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1190/segam2014-0134.1},
Abstract = {Surface to borehole electromagnetic (SBEM) is a potential
tool for reservoir monitoring. However, it is difficult to
give a good resolution in reservoir imaging in the
horizontal direction due to the fact that receivers are
located only inside the borehole. Multiple sources are a
natural choice to overcome this problem, but the resultant
required memory and CPU time are large due to multiple
sources and complex inhomogeneous media. A two-dimensional
biconjugate gradient fast Fourier transform (BCGS-FFT)
method is developed for multiple sources in a layered medium
for vertical electromagnetic profiling of the surface to
borehole method. With the help of the presented solver,
vertical electromagnetic profiling for reservoir monitoring
would be possible.},
Doi = {10.1190/segam2014-0134.1},
Key = {fds341217}
}
@article{fds341218,
Author = {Jia, Y and Liu, QH and He, Z},
Title = {Fast three-dimensional electromagnetic nonlinear inversion
method for imaging in a layered medium with application in
geophysical exploration using BCGS-FFT},
Journal = {Society of Exploration Geophysicists International
Exposition and 84th Annual Meeting Seg 2014},
Pages = {3868-3871},
Year = {2014},
Month = {January},
ISBN = {9781634394857},
url = {http://dx.doi.org/10.1190/SEG-2014-1652.pdf},
Abstract = {This paper presents an efficient three-dimensional nonlinear
electromagnetic inversion method in a multilayered medium
for geophysical exploration. The stabilized
biconjugate-gradient fast Fourier transform algorithm is
used for forward modeling, whereas the distorted Born
iterative method is used in the inversion. The
conjugate-gradient method is applied at each inversion
iteration to minimize the cost function. The usage of an
iterative solver based on the FFT algorithm and the
developed recursive matrix method combined with an
interpolation technique to evaluate the layered medium
Green's functions rapidly, make this method highly
efficient, with the requirement of very low time and memory,
(N log N ) and (N ) respectively. Numerical experiments
about the 3D forward modeling with application in Borehole
to Surface Electromagnetic Method will be presented in this
paper; in addition, we will show the examples about 3D
inversion applied in geophysical exploration. All these
results will demonstrate the high efficiency and accuracy of
the proposed method.},
Doi = {10.1190/SEG-2014-1652.pdf},
Key = {fds341218}
}
@article{fds341219,
Author = {Jia, Y and Liu, QH and He, Z},
Title = {Fast three-dimensional electromagnetic nonlinear inversion
method for imaging in a layered medium with application in
geophysical exploration using BCGS-FFT},
Journal = {Seg Technical Program Expanded Abstracts},
Volume = {33},
Pages = {654-658},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1190/segam2014-1652.1},
Abstract = {This paper presents an efficient three-dimensional nonlinear
electromagnetic inversion method in a multilayered medium
for geophysical exploration. The stabilized
biconjugate-gradient fast Fourier transform algorithm is
used for forward modeling, whereas the distorted Born
iterative method is used in the inversion. The
conjugate-gradient method is applied at each inversion
iteration to minimize the cost function. The usage of an
iterative solver based on the FFT algorithm and the
developed recursive matrix method combined with an
interpolation technique to evaluate the layered medium
Green's functions rapidly, make this method highly
efficient, with the requirement of very low time and memory,
O (N log N) and O (N) respectively. Numerical experiments
about the 3D forward modeling with application in Borehole
to Surface Electromagnetic Method will be presented in this
paper; in addition, we will show the examples about 3D
inversion applied in geophysical exploration. All these
results will demonstrate the high efficiency and accuracy of
the proposed method.},
Doi = {10.1190/segam2014-1652.1},
Key = {fds341219}
}
@article{fds283533,
Author = {Pierri, R and Bolomey, JC and Liu, QH and Soldovieri,
F},
Title = {Inverse scattering and microwave tomography in safety,
security, and health},
Journal = {International Journal of Antennas and Propagation},
Volume = {2013},
Pages = {1-2},
Publisher = {Hindawi Limited},
Year = {2013},
Month = {December},
ISSN = {1687-5869},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000327641900001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Doi = {10.1155/2013/589598},
Key = {fds283533}
}
@article{fds283491,
Author = {Liu, N and Tang, Y and Zhu, X and Tobon, L and Liu, Q},
Title = {Higher-order mixed spectral element method for Maxwell
eigenvalue problem},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1646-1647},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711482},
Abstract = {Conventional edge elements in solving vector Maxwell's
equations by the finite element method will lead to the
presence of spurious zero eigenvalues. Here we describes a
higher order mixed spectral element method (mixed SEM) for
the computation of two-dimensional TEz eigenvalue problem of
Maxwell's equations. It utilizes Gauss-Lobatto-Legendre
(GLL) polynomials as the basis functions in the
finite-element framework with the weak divergence condition.
It is shown that this method can suppress all spurious zero
and nonzero modes and has spectral accuracy with analytic
eigenvalues. Numerical results are given on homogeneous and
doubly connected cavities to verify its merits. © 2013
IEEE.},
Doi = {10.1109/APS.2013.6711482},
Key = {fds283491}
}
@article{fds283501,
Author = {Tobon, LE and Liu, QH},
Title = {New efficient and naturally parallelizable time integration
algorithm applied to sequential domains for
DG-TD},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {50},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715356},
Abstract = {The discontinuous Galerkin time-domain (DGTD) methods are
promising in transient analysis of large and multiscale
problems. Based on the idea of domain decomposition, the DG
method can handle problems too large to be solved by
conventional numerical techniques. Basically, the DG method
divides an original problem into several well designed
subdomains, i.e., split a large system matrix into several
smaller and balanced matrices. Thus, once the spatial
discretization is defined, an optimal time integration
method is crucial. © 2013 IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715356},
Key = {fds283501}
}
@article{fds283502,
Author = {Liu, Y and Xiong, X and Chen, S and Liu, QH and Liao, K and Zhu,
J},
Title = {Direction-of-arrival estimation for closely coupled dipoles
using embedded pattern diversity},
Journal = {Isap 2013 Proceedings of the 2013 International Symposium on
Antennas and Propagation},
Volume = {1},
Pages = {467-469},
Year = {2013},
Month = {December},
Abstract = {Direction-of-arrival (DOA) estimation for very closely
spaced dipoles (no larger than 0.1 wavelength) is
considered. In contrast to reducing the mutual coupling
effect in conventional DOA methods, we demonstrate in this
work that the mutual coupling can produce amplitude and
phase difference of embedded element patterns, which can be
utilized to greatly improve DOA estimation performance by
incorporating the pattern diversity into the estimation
algorithm. Simulation results show that two coupled dipoles
achieve much higher DOA estimation accuracy than the ones
without mutual coupling (for example, with the basic
multiple signal classification (MUSIC) algorithm, the two
coupled dipoles can achieve the root-mean-squared error
(RMSE) of 1° within 120° arriving angle range for the
spacing of 0.1 wavelength and RMSE of 2° within 90° range
for only 0.02 wavelength, at moderately high SNR and
sampling condition) © 2013 Antenna Society of the Chinese
Institute of Electronics.},
Key = {fds283502}
}
@article{fds283503,
Author = {Zhu, X and Zhao, Z and Yang, K and Wu, J and Liu, QH},
Title = {A scaled experimental system for Underwater Seismic Imaging
and exploration},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {834-835},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711076},
Abstract = {Underwater Seismic Imaging (USI) is an acoustic technology
that can provide the geographic information of seafloor and
sub-seafloor. A laboratory sized scaled experiment system of
the underwater seismic imaging system is designed and built
to support the imaging and inversion algorithm research of
USI. It integrates the fundamental electronic instruments
and acoustic sensors with computer and basic control
programs, can providing the ability of scaled USI
experiments for real dimension as 2000 meters wide and 1500
meters depth, with real seismic frequency from 5Hz to 20Hz.
© 2013 IEEE.},
Doi = {10.1109/APS.2013.6711076},
Key = {fds283503}
}
@article{fds283504,
Author = {Tan, T and Liu, QH},
Title = {Unconditionally stable locally tridiagonal iterative FDTD
for high loss applications},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {900-901},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711109},
Abstract = {We first show the ADI numerical errors when measured against
the Crank-Nicolson scheme are quadratically proportional to
both the temporal discretization and lossy values. The ADI
method is therefore ineffective for lossy wave propagation
simulations requiring larger temporal resolution. Locally
tridiagonal iterative methods are then developed to avoid
such errors. Standard Jacobi, Gauss-Seidel and Successive
Over-Relaxation methods can all be used. In contrast to the
ADI method, numerical results demonstrate that the proposed
iterative method is extremely effective for high loss
problems - reaching a large CFL value limited only by the CN
equations. © 2013 IEEE.},
Doi = {10.1109/APS.2013.6711109},
Key = {fds283504}
}
@article{fds283505,
Author = {Wu, J and Zhao, Z and Song, J and Zhu, X and Nie, Z and Liu,
QH},
Title = {A wideband printed antenna with unidirectinal radiation
characteristics},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1524-1525},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711421},
Abstract = {Aiming to achieve wideband and unidirectional radiation, a
planar printed antenna with two closely spaced strips is
proposed and fabricated. This antenna consists of a printed
rectangular loop and two metallic strips. The rectangular
loop has a good direction but has a drawback of narrow band.
According to the closely spaced loading theory, the
impedance at the upper frequency will decrease when the two
metallic strips is placed at the maximum radiation direction
of the rectangular loop. This improves the impedance
matching. Thus the impedance bandwidth is greatly expanded.
In order to demonstrate the effectiveness of the double
strips, a prototype of the antenna is fabricated and tested.
Experimental results show good performance of the proposed
antenna. It has a 62.7% measured bandwidth, ranging from
2.29 to 4.38 GHz. The measured F/B (front-to-back) ratio is
larger than 8 dB in the whole frequency band. © 2013
IEEE.},
Doi = {10.1109/APS.2013.6711421},
Key = {fds283505}
}
@article{fds283506,
Author = {Li, D and Zhu, J and Wu, S and Xiong, X and Liu, Y and Liu,
QH},
Title = {Field-circuit co-simulation for microwave metamaterials with
nonlinear components},
Journal = {Isap 2013 Proceedings of the 2013 International Symposium on
Antennas and Propagation},
Volume = {2},
Pages = {1131-1133},
Year = {2013},
Month = {December},
Abstract = {We demonstrate an analysis of the metamaterials medium
consisting of SRRs (split ring resonators) integrated with
nonlinear microwave components based on a circuit and 3D
electromagnetic wave co-simulation method. The simulations
are performed by using Wavenology EM, which is an efficient
multiphysics and multiscale wave simulator. Our
investigations show that the resonant frequency of the SRR
loaded by a varactor reduces slightly when incident wave
power increases, which is consistent with previous
experimental research. We propose to connect an adjustable
capacitor in parallel with the varactor to tune the resonant
frequency. The simulation results indicate the tuning range
is from 12.30 to 14.92 GHz, and the resonant frequency and
quality factor decrease as the parallel capacitance
increases. © 2013 Antenna Society of the Chinese Institute
of Electronics.},
Key = {fds283506}
}
@article{fds283507,
Author = {Tobon, LE and Ren, Q and Liu, QH},
Title = {A new efficient non-spurious 3D DG-FETD for large and
multiscale electromagnetic systems},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {45},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715351},
Abstract = {The discontinuous Galerkin finite-element time-domain
(DG-FETD) method is useful in transient simulations of
multiscale electromagnetic systems. Its special capability
in geometric modeling, by dividing the computational domain
in several domains, transforms a large system into several
moderate-sized matrix equations. The numerical fluxes, which
communicate fields between domains, are defined by
tangential components of E and H on the interfaces; for this
reason, the conventional DG-FETD is traditionally based on
these two variables. © 2013 IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715351},
Key = {fds283507}
}
@article{fds283508,
Author = {Song, J and Zhao, Z and Wu, J and Zhu, X and Nie, Z and Liu,
QH},
Title = {Thermo-acoustic imaging for different breast tissues in
microwave induced thermo-acoustic tomography
system},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2032-2033},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711674},
Abstract = {Microwave induced thermo-acoustic tomography (MITAT)
combines the advantages of both ultrasound imaging and
microwave imaging. In this paper, a secure and accurate
MITAT system has been developed. Aiming to demonstrate the
capability of MITAT in breast cancer detection, experiments
by using real breast tissues and breast tumor specimen have
been performed. The results show the high contrast of the
developed MITAT system. The distinguishing ability for
tumors at different clinical stages has been studied. The
experimental results show that developed MITAT system can
distinguish not only the normal and cancer specimens but
also the cancer tissue specimens at different clinical
stages. © 2013 IEEE.},
Doi = {10.1109/APS.2013.6711674},
Key = {fds283508}
}
@article{fds283509,
Author = {Yu, Z and Chai, M and Mix, JA and Slattery, KP and Liu,
QH},
Title = {An iterative least-square based technique for high
resolution source reconstruction with phaseless near field
scan data},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {33},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715339},
Abstract = {Due to continuous increasing operating frequency and
shrinking component scale, considerable attention has been
drawn to electromagnetic interference (EMI) and signal
integrity (SI) problems in microelectronics. To solve these
problems, near field scan (NFS) is adopted to locate
radiating sources on devices under test (DUT). During the
NFS process, ultra close-to-surface scan is required to
enhance the resolution of scanned images due to the
evanescing nature of electromagnetic fields. To compensate
for the evanescence effect, recently inversion techniques
have been employed. Inversion methods consider the radiating
model of DUTs and reconstruct radiating sources based on
scanned fields. The advantages of inversion methods
including more flexibility for scan height and higher
resolution on reconstructed images. However, conventional
inversion methods require both magnitude and phase
information of scanned fields. Obtaining phase information
of near fields will dramatically increase the complexity
and/or time of a NFS process. One possible way to overcome
this problem is to utilize only the magnitude of radiated
fields during inversion process. Unfortunately this attempt
will result in solving a set of nonlinear equations which
significantly increases the computational complexity of this
problem. © 2013 IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715339},
Key = {fds283509}
}
@article{fds283510,
Author = {Qi, CH and Zhao, ZQ and Yang, K and Nie, ZP and Liu,
QH},
Title = {Scattering and Doppler spectral analysis for a flying target
above a 3-D sea surface},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {832-833},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711075},
Abstract = {Aiming to find the Doppler spectra of a flying target at low
altitude above a sea surface, an iterative hybrid method is
employed to solve this complex composite 3-dimensional (3-D)
electromagnetic scattering problem. This method calculates
electromagnetic (EM) scatterings of the target and the sea
surface separately, and then the mutual EM coupling effects
are added through an iterative process. The Doppler spectra
from the target flying at different velocities are analyzed
by using quasi-stationary algorithm at different incident
angles. The influence on the Doppler spectral broadening
which is induced by the EM coupling effects is analyzed as
well. © 2013 IEEE.},
Doi = {10.1109/APS.2013.6711075},
Key = {fds283510}
}
@article{fds283511,
Author = {Zhang, Y and Yuan, M and Liu, QH},
Title = {An impulse electromagnetic interference shielding based on a
diode grid},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {5},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715311},
Abstract = {It is necessary to protect electronic components and systems
from the intentional or unintentional broadband impulse
electromagnetic interference (EMI). The previously reported
shielding permits the waves in the desired frequency band to
be transparent, and stop the wave in the other frequency
bands. This paper proposes a new impulse EMI shielding based
on a diode grid. The proposed shielding is transparent to
the electromagnetic wave when it is weak, but prevents the
incident wave from transmitting when it is strong. The
shielding permits the electronic systems to communicate with
each other in a normal electromagnetic environment, but
protects them from the intentional impulse EMI. The
effectiveness of the shielding is evaluated using
Wavenology™, a commercial full wave transient field
simulator integrated with the nonlinear SPICE circuit
solver. The paper also discusses the dependence of shielding
on some important design factors such as the electromagnetic
frequency and the size of the unit cell. © 2013
IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715311},
Key = {fds283511}
}
@article{fds283512,
Author = {Yu, Z and Zhang, W and Liu, QH},
Title = {A three-dimensional BCGS-FFT method for inhomogeneous
anisotropic scatterers with high dielectric and magnetic
contrasts},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {104},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715410},
Abstract = {Although computational capabilities have been substantially
enhanced over the last few decades, fast and accurate
forward solvers for scattering and imaging applications are
still attracting much attentions with new advances. To deal
with the scattering of dielectric objects, methods involving
integral equations are attractive because of reduced number
of unknowns. As a conventional way to solve integral
equations, the method of moments (MOM) with N unknowns takes
about O(N3) CPU time and O(N2) computer memory. This
requirement is prohibitively expensive for large problems,
especially for volume integral equations where N is
proportional to the volume of the 3D inhomogeneous
scatterer. CG-FFT method was proposed to reduce the
computational complexity by employing the fast Fourier
transform to calculate convolution operators in the integral
equations. The resulting linear system is then solved by an
iterative method, namely conjugate gradient (CG) method.
Therefore, the requirements for CPU time and computer memory
can be greatly reduced. Furthermore, CG-FFT method is
accelerated by the stabilized biconjugate-gradient FFT
(BCGS-FFT) method (X. Xu, Q.H. Liu, Z.Q. Zhang, J. Appl.
Comput. Electromag. Soc. 17, 1, 97-103, 2002). However, most
of the work mentioned above considers only homogeneous
anisotropic scatterers and/or scatterers with non-magnetic
materials with a low contrast. © 2013 IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715410},
Key = {fds283512}
}
@article{fds283513,
Author = {Zhang, W and Liu, QH},
Title = {Nanoparticles for electromagnetic fields enhancement in
cross well imaging of subsurface},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {197},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715503},
Abstract = {During the past two decades there has been increasing
interest in the cross well imaging of the subsurface for oil
exploration applications. As more and more deviated and
horizontal wells are drilled in an attempt to increase the
oil production, the azimuthal symmetry no longer holds. Up
to present, many numerical methods have been developed for
the forward modeling of 3-D cross well logging, including
the finite element method (C. Li, B. Xiong, and Y. Lv,
Geophysical and Geochemical Exploration, 36, 585-590, 2012),
stabilized biconjugate gradient fast Fourier transform
method (BCGS-FFT) (Z. Q. Zhang, and Q. H. Liu, Trans.
Geosci. and Remote Sens., 41, 998-1104, 2003) and extended
Born approximation (H. Tseng and K. Lee, Twenty-Ninth
Workshop on Geothermal Reservoir Engineering, 2004). © 2013
IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715503},
Key = {fds283513}
}
@article{fds283514,
Author = {Yang, K and Zhao, Z and Zhu, X and Liu, QH},
Title = {Robust adaptive beamforming with low sidelobe
levels},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {872-873},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711095},
Abstract = {Adaptive beamformers will degrade severely when the array
weights cannot adapt as fast as the environmental changes,
especially when unexpected interferences exist. Low sidelobe
levels can increase the ability to suppress the white noise
and unexpected interferences. The adaptive beamforming with
low sidelobe levels is transformed into a weighted pattern
synthesis problem. This weighting function in the sidelobe
region is the Capon spatial spectrum which has peaks at the
directions of interferences and the interferences will be
suppressed by degrading the sidelobe levels. The proposed
method is demonstrated through a uniform linear array. ©
2013 IEEE.},
Doi = {10.1109/APS.2013.6711095},
Key = {fds283514}
}
@article{fds283515,
Author = {Wang, J and Zhao, Z and Wu, J and Yang, K and Nie, Z and Liu,
QH},
Title = {Electromagnetic inverse scattering series (ISS) method for
sensing 2-D objects buried in layered media with unknown
dielectric properties},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {536-537},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6710928},
Abstract = {To reconstruct objects buried in layered media, most of
current imaging methods are based on a common assumption
that the dielectric properties of layered media are given.
However, this assumption is unrealistic in practice. To
study a more realistic electromagnetic inverse scattering
problem in which the dielectric properties of layered media
are not given, an inverse scattering series (ISS) method
which has been used in seismic exploration is extended into
electromagnetic field. By using the developed ISS method,
objects buried in layered media can be imaged without
knowing the dielectric properties of layered media a prior.
The feasibility of the improved ISS method has been
demonstrated by some numerical simulations. © 2013
IEEE.},
Doi = {10.1109/APS.2013.6710928},
Key = {fds283515}
}
@article{fds283516,
Author = {Yang, K and Zhao, Z and Zhu, X and Liu, QH},
Title = {Resolving ambiguities in DOA estimation by optimizing the
element orientations},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1326-1327},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711323},
Abstract = {A method of resolving ambiguities in direction-of-arrival
(DOA) estimation for sparse linear arrays with directional
antennas is reported. The DOA estimation ambiguity comes
from the linear dependence among the array manifold vectors
of different DOAs. Optimizing the element orientations can
break down the linearity. The element orientations are
optimized by using particle swarm optimization (PSO)
algorithm with the Weiss-Weinstein bound (WWB). This method
is demonstrated through simulations of a 5-element collinear
array of dipole antennas. © 2013 IEEE.},
Doi = {10.1109/APS.2013.6711323},
Key = {fds283516}
}
@article{fds283517,
Author = {Dai, J and Liu, QH},
Title = {Fast computation of electromagnetic fields in anisotropic
media layered both vertically and cylindrically using the
numerical mode matching (NMM) method},
Journal = {2013 Usnc Ursi Radio Science Meeting (Joint With Ap S
Symposium), Usnc Ursi 2013 Proceedings},
Pages = {142},
Publisher = {IEEE},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/USNC-URSI.2013.6715448},
Abstract = {A structure layered both vertically and horizontal
cylindrically is a special 3D inhomogeneous medium with
axial symmetry and has many engineering applications. An
off-axis source will generate full three-dimensional
electromagnetic fields in such a medium. Typical
applications of such electromagnetic simulation include
geophysical exploration, optical fiber communications and
integrated optics. For example, in geophysical exploration,
the induction well-logging tool consisting triaxial coils
will produce nonaxisymmetric electromagnetic waves in a
heterogeneous formation. © 2013 IEEE.},
Doi = {10.1109/USNC-URSI.2013.6715448},
Key = {fds283517}
}
@article{fds283518,
Author = {Wang, L and Liu, QH and Joines, WT and Yuan, MQ},
Title = {Magnetic antenna based on two dimensional DC superconducting
quantum interference filter},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1396-1397},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711357},
Abstract = {We first theoretically present a magnetic antenna based on a
two dimensional DC superconducting quantum filter device.
This antenna may detect the dynamical magnetic field instead
of the absolute magnetic field. We call it B-antenna since
it only responses to the external magnetic field. We show
the robustness of 2D SQIF structure when the 2D SQIF chip
encounters statistical distributions of the fabrication of
individual Josephson junctions. Finally, we find that
B-antenna can work properly even though the bias current is
smaller than the critical current. Our research opens the
dimensions of novel ultra-sensitive antennas by combing
superconducting quantum interference filter devices and
classic electromagnetic waves. © 2013 IEEE.},
Doi = {10.1109/APS.2013.6711357},
Key = {fds283518}
}
@article{fds283519,
Author = {Xu, K and Zhang, Y and Fan, Y and Joines, WT and Liu,
QH},
Title = {Microstrip multi-band bandpass filters using a single
improved ring resonator},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {794-795},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2013.6711056},
Abstract = {A planar dual-mode ring resonator loaded by four
mushroom-shaped stubs is presented for design of dual-band
bandpass filter (BPF). The four mushroom-shaped stubs
utilized in the inner area of the traditional dual-mode ring
resonator can realize both compact size and controllable
harmonic response of the filter to generate the second
passband. Additionally, a novel pair of feed lines with
source-load coupling is employed to not only feed the ring
resonator but also generate the higher third passband when
the length of feed lines increases. For demonstration
purpose, two example filters (dual-band BPF and tri-band
BPF) are implemented. © 2013 IEEE.},
Doi = {10.1109/APS.2013.6711056},
Key = {fds283519}
}
@article{fds283523,
Author = {Xu, K and Zhang, Y and Wang, L and Joines, WT and Liu,
QH},
Title = {SPICE model of memristor and its application},
Journal = {2007 50th Midwest Symposium on Circuits and
Systems},
Pages = {53-56},
Publisher = {IEEE},
Year = {2013},
Month = {December},
ISSN = {1548-3746},
url = {http://dx.doi.org/10.1109/MWSCAS.2013.6674583},
Abstract = {In this paper, a circuit model of the memristor using SPICE
is presented, which expands the hitherto methods to solve
the memristor's modeling equations presented by HP lab. This
kind of the memristor model can not only be encoded in SPICE
and satisfy the properties of the general memristive
systems, but also use few components and simulate fast. In
order to further explore the nonlinear and switching
characteristics of the memristor model, a directly modulated
patch antenna with one memristor is designed by using
finite-difference time-domain (FDTD) simulator integrated
with the nonlinear SPICE circuit solver. © 2013
IEEE.},
Doi = {10.1109/MWSCAS.2013.6674583},
Key = {fds283523}
}
@article{fds283528,
Author = {Ellis, MS and Zhao, Z and Wu, J and Nie, Z and Liu, QH},
Title = {A novel miniature band-notched wing-shaped monopole
ultrawideband antenna},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {12},
Pages = {1614-1617},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {December},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2013.2294346},
Abstract = {A small band-notched monopole ultrawideband (UWB) antenna is
proposed in this letter. In this antenna, the band-reject is
achieved by attaching a strip to the hollow center of a
wing-shaped monopole. The height and width of the strip are
dependent on the center frequency of the notch band. The
proposed antenna is printed on a very small (11×,15mm2)
substrate. The measured results reveal that the proposed
antenna offers a wide bandwidth covering 5-15 GHz with a
notched band covering a 6.7-7.1-GHz IEEE
INSAT/super-extended C-band frequency. The proposed antenna
shows very narrow and accurate band rejection. © 2013
IEEE.},
Doi = {10.1109/LAWP.2013.2294346},
Key = {fds283528}
}
@article{fds283540,
Author = {Li, J and He, Z and Liu, QH},
Title = {Higher-order statistics correlation stacking for DC
electrical data in the wavelet domain},
Journal = {Journal of Applied Geophysics},
Volume = {99},
Pages = {51-59},
Publisher = {Elsevier BV},
Year = {2013},
Month = {December},
ISSN = {0926-9851},
url = {http://dx.doi.org/10.1016/j.jappgeo.2013.10.001},
Abstract = {DC (direct current) electrical and shallow seismic methods
are indispensable to the near surface geophysical
exploration, but the near surface areas are very difficult
environments for any geophysical exploration due to the
random noise caused by near surface inhomogeneities. As a
new algorithm based on higher-order statistics theory, the
higher-order correlation stacking algorithm for seismic data
smoothing in the wavelet domain has been developed and
applied efficiently to filter some correlation noise that
the conventional second-order correlation stacking could not
inhibit. In this paper, this higher-order statistics
correlation stacking technology is presented for DC
electrical data in wavelet domain. Taking into account the
single section and multiple section data, we present two new
formulations of correlation stacking for DC electrical data.
Synthetic examples with Gaussian noise are designed to
analyze the overall efficiency of the new algorithm and to
determine its efficacy. Meanwhile, comparison with the
traditional least-squares optimization inversion method for
field examples from electrical imaging surveys and
time-domain IP measurement in China shows its significant
advantages. The quality of the new algorithm also has been
assessed by physical simulation experiments. This new
technology in DC electrical exploration measurements
provides a new application in engineering and mining
investigation. © 2013 Elsevier B.V.},
Doi = {10.1016/j.jappgeo.2013.10.001},
Key = {fds283540}
}
@article{fds283544,
Author = {Wu, J and Li, Z and Yang, J and Huang, Y and Liu, QH},
Title = {Focusing translational variant bistatic forward-looking SAR
using extended nonlinear Chirp Scaling algorithm},
Journal = {Ieee National Radar Conference Proceedings},
Publisher = {IEEE},
Year = {2013},
Month = {October},
ISSN = {1097-5659},
url = {http://dx.doi.org/10.1109/RADAR.2013.6586066},
Abstract = {With appropriate geometry configurations, bistatic Synthetic
Aperture Radar (SAR) can break through the limitations of
monostatic SAR for forward-looking imaging. This paper
develops an extended nonlinear Chirp Scaling imaging
algorithm for translational variant BFSAR. The method
utilizes a point target reference spectrum of generalized
Loffeld's bistatic formula (GLBF). Without bistatic
deformation term, GLBF is the latest development of
Loffeld's bistatic formula. After an azimuth frequency
transformation in 2-D frequency domain, the azimuth spatial
variation is removed. Then through a fourth-order frequency
domain filtering, the algorithm can consider the quadratic
variance term of the range frequency modulated rate and the
linear term of the tertiary coupling phase term along
cross-track direction. In addition, by a fourth-order
nonlinear Chirp Scaling equalization operation, the
algorithm can finish the correction of quadratic range cell
migration in terms of range. The result of this paper can be
used for forward-looking reconnaissance, guidance and so on.
© 2013 IEEE.},
Doi = {10.1109/RADAR.2013.6586066},
Key = {fds283544}
}
@article{fds283542,
Author = {Liu, J and Zhao, Z and He, Z and Nie, Z and Liu, QH},
Title = {Resolving manifold ambiguities for direction-of-arrival
estimation of sparse array using semi-circular
substrates},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {7},
Number = {12},
Pages = {1016-1020},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2013},
Month = {September},
ISSN = {1751-8725},
url = {http://dx.doi.org/10.1049/iet-map.2012.0417},
Abstract = {Sparse linear array has some advantages over uniform linear
array in some applications. However, it is well known that
sparse array always suffers from manifold ambiguity, which
has significant influence on direction-of-arrival (DOA)
estimation and resolution. In this study, a new method based
on the multiple signal classification (MUSIC) for resolving
manifold ambiguities of uncorrelated sources by using
semi-circular substrate is proposed for DOA estimation of
sparse array. Spurious MUSIC peak spectrums are generated
because of a linear combination of the steering vectors of
true DOAs. The main idea of the proposed method is to setup
one or several semi-circular medium substrates at the front
of some elements. The phases of these elements are changed
through the refractive index and the radii of those
semi-circular substrates. This treatment breaks down the
previous linearity of the steering vectors for the array
without adding the substrates. Thus, true DOA peaks can be
discriminated according to this feature. Simulation results
show good performance of the proposed method. Trivial and
nontrivial ambiguities are efficiently resolved. © The
Institution of Engineering and Technology
2013.},
Doi = {10.1049/iet-map.2012.0417},
Key = {fds283542}
}
@article{fds283543,
Author = {Xu, KD and Zhang, YH and Joines, WT and Liu, QH and Fan,
Y},
Title = {Tri-band bandpass filter using shorted stub-loaded dual-mode
resonators},
Journal = {Microwave Journal},
Number = {9},
Pages = {122-130},
Year = {2013},
Month = {September},
ISSN = {0192-6225},
Abstract = {A compact tri-band bandpass filter (BPF) using three shorted
stub-loaded dual-mode resonators (SSLDMR) is presented. To
verify the approach, three single-band filters with only one
folded SSLDMR and the same pair of meandering feed lines are
each simulated by using the Ansoft HFSS simulator. All the
other dimensions are fixed except the stub lengths. Since
the coupling paths of the three passbands are isolated, the
center frequency and bandwidth of all three passbands can be
flexibly controlled by tuning the electrical length of the
corresponding resonators and shorted stubs, respectively.
Moreover, each passband can be independently adjusted
without affecting the other two. A prototype of a tri-band
BPF centered at 2.4, 3.5 and 5.2 GHz has been designed and
fabricated with six transmission zeros. Six transmission
zeros on either side of three passbands are located at 2.17,
2.62, 3.04, 3.94, 4.55 and 5.65 GHz.},
Key = {fds283543}
}
@article{fds283550,
Author = {Zhu, J and Liu, QH and Lin, T},
Title = {Manipulating light absorption of graphene using plasmonic
nanoparticles.},
Journal = {Nanoscale},
Volume = {5},
Number = {17},
Pages = {7785-7789},
Year = {2013},
Month = {September},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23864077},
Abstract = {We present the incorporation of periodic gold nanoparticle
arrays into graphene-based photodetectors to enhance and
tune light absorption of graphene. By the use of
electromagnetic simulations, we show that light absorption
in graphene can be manipulated by tuning plasmonic
resonance. A maximum absorption of 30.3% with a full width
of 135 nm at half maximum is achieved through systematic
optimization of nanostructures.},
Doi = {10.1039/c3nr02660d},
Key = {fds283550}
}
@article{fds283549,
Author = {Chen, J and Tobon, L and Huo Liu and Q},
Title = {Locally implicit discontinuous Galerkin finite element
method for transient analysis of 3D layered structures with
electrically small details},
Journal = {Microwave and Optical Technology Letters},
Volume = {55},
Number = {8},
Pages = {1912-1916},
Publisher = {WILEY},
Year = {2013},
Month = {August},
ISSN = {0895-2477},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000319522800053&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {An efficient locally implicit discontinuous Galerkin finite
element method is proposed for time domain analysis of 3D
layered problems. The vector mixed finite elements with
discontinuous Galerkin method are employed for spatial
discretization, and the singly diagonally implicit
Runge-Kutta scheme is used for time stepping. The block
Thomas algorithm is utilized during time integration to
eliminate the subdomain-based iteration. Numerical examples
demonstrate the proposed method is efficient in simulating
3D layered structures containing electrically small
components. Copyright © 2013 Wiley Periodicals,
Inc.},
Doi = {10.1002/mop.27673},
Key = {fds283549}
}
@article{fds283559,
Author = {Zhu, X and Zhao, Z and Wang, J and Song, J and Liu, QH},
Title = {Microwave-induced thermal acoustic tomography for breast
tumor based on compressive sensing.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {60},
Number = {5},
Pages = {1298-1307},
Year = {2013},
Month = {May},
ISSN = {0018-9294},
url = {http://dx.doi.org/10.1109/tbme.2012.2233737},
Abstract = {Microwave-induced thermal acoustic tomography (MITAT) is an
innovative technique to image biomedical tissues based on
their electric properties. It has the advantages of both
high contrast and high spatial resolution. Image
reconstruction method in MITAT is always a critical issue.
In this paper, a CS-MITAT (CS: compressive sensing) imaging
method is proposed. Compressive sensing (CS) is a recently
developed sparse signal representation and analysis
framework which handles medical imaging measurements using
low sampling rate or increasing imaging quality. The
CS-MITAT imaging method applies CS theory to the MITAT for
breast tumor imaging. In this method, an over-complete
dictionary is established to make sparse measurements in the
spatial domain. This treatment greatly saves measurement
time. Simulations and experiments with real breast tumor
tissues demonstrate the feasibility and effectiveness of the
method. Compared with conventional time reversal mirror
method which has been used in MITAT research, CS-MITAT
provides the same peak signal-to-noise ratio imaging quality
by using significantly fewer acoustic sensor positions or
scanning times.},
Doi = {10.1109/tbme.2012.2233737},
Key = {fds283559}
}
@article{fds283558,
Author = {Chen, G and Wang, X and Liu, Q},
Title = {Microwave-induced thermo-acoustic tomography system using
TRM-PSTD technique},
Journal = {Progress in Electromagnetics Research B. Pier
B},
Volume = {48},
Number = {48},
Pages = {43-59},
Publisher = {EMW Publishing},
Year = {2013},
Month = {March},
ISSN = {1937-6472},
url = {http://dx.doi.org/10.2528/PIERB12111503},
Abstract = {Time reversal imaging method based on full wave numerical
technique for likely breast tumors biological tissue in the
Microwave-Induced Thermo-Acoustic Tomography (MITAT) system
is discussed. In this paper, the mechanism of
microwave-induced thermo-acoustic is strictly described
based on thermodynamics and thermo-diffusion principles; the
equivalent relationship between the absorbed microwave
energy distribution of the biological tissue and the induced
thermo-acoustic source distribution is used as the basis of
the imaging algorithm. Due to its unique noise suppression
feature and the stability of the algorithm, the Time
Reversal Method (TRM) based on the Pseudospectral
Time-Domain (PSTD) technique is applied to image
heterogeneous phantom tissues from low Signal-to-Noise-Ratio
(SNR) thermo-acoustic signals. Thereafter, an integrated
MITAT prototype system is presented to obtain the
thermo-acoustic signals from some biologic tissue with
millimeter scale. The proposed TRM method is based on PSTD
technique produced two-dimensional images, presented to
study the performances of the MITAT in terms of contrast and
resolution. These images prove predominant advantages in
both contrast and resolution compared with conventional
microwave and ultrasound imaging systems for malignant tumor
detection. Based on the current results, our TRM-PSTD MITAT
system provides evidence to predict breast tumor in an early
stage and millimeter scale.},
Doi = {10.2528/PIERB12111503},
Key = {fds283558}
}
@article{fds283557,
Author = {Chen, G and Wang, X and Wang, J and Zhao, Z and Nie, Z and Liu,
Q},
Title = {Tr adjoint imaging method for MITAT},
Journal = {Progress in Electromagnetics Research B. Pier
B},
Volume = {46},
Number = {46},
Pages = {41-57},
Publisher = {EMW Publishing},
Year = {2013},
Month = {March},
ISSN = {1937-6472},
url = {http://dx.doi.org/10.2528/PIERB12072411},
Abstract = {Most of the current imaging methods in microwave induced
thermoacoustic tomography (MITAT) system assume that the
heterogeneous sound velocity (SV) and density distribution
are given or subject to Gaussian distribution. These
situations generally are not satisfied. To improve
multi-targets thermoacoustic sources imaging quality in a
heterogeneous tissue, an iterative TR adjoint imaging method
is proposed. The proposed iterative TR adjoint method can
reconstruct thermoacoustic sources from the measured data
even if the prior heterogeneous information of the tissue is
unknown. This method estimates misfit between synthesized
and observed measured signals, and iteratively updates
supposed model parameters which give the heterogeneous
tissue structure. In this iterative procedure, error kernels
of SV, density and the approximate point source position
information can be obtained independently. After the time of
fiight (TOF) convergence criterion is reached, a regular
time reversal (TR) method with updated model will give out
the final imaging result. The proposed TR adjoint imaging
method is based on strictly theoretical derivation, and some
simulations are presented to validate the
method.},
Doi = {10.2528/PIERB12072411},
Key = {fds283557}
}
@article{fds283474,
Author = {Feng, N and Liu, QH and Zhu, C},
Title = {Simple and efficient BZT-higher-order PML formulations for
the metal plate buried in three-dimensional dispersive soil
space problems},
Journal = {Applied Computational Electromagnetics Society
Journal},
Volume = {28},
Number = {10},
Pages = {909-916},
Year = {2013},
Month = {January},
ISSN = {1054-4887},
Abstract = {Efficient and unsplit-field higher-order PML formulations
using the stretched coordinate perfectly matched layer
(SC-PML) formulations and the bilinear Z-Transform (BZT)
method are presented for truncating the finite-difference
time-domain (FDTD) lattices. This method is completely
independent of the material properties of the FDTD
computational domain and hence can be applied to the
modeling of arbitrary media without any modification because
of the D-B constitutive relations used. The higher-order PML
has the advantages of both the conventional PML and the
complex frequency-shifted PML (CFS-PML) in terms of
absorbing performances. Two 3D FDTD simulations of the metal
plate buried in dispersive soil space FDTD domains have been
carried out to validate these formulations. It is shown that
the proposed PML formulations with the higher-order scheme
are efficient in terms of attenuating both the low-
frequency propagating waves and evanescent waves and
reducing late-time reflections. © 2013 ACES.},
Key = {fds283474}
}
@article{fds283496,
Author = {Lei, S and Zhao, Z and Zhou, X and Nie, Z and Liu, QH},
Title = {Polarization optimization in clutter background via target
scattering estimation},
Journal = {2013 International Conference on Communications, Circuits
and Systems, Icccas 2013},
Volume = {2},
Pages = {161-165},
Publisher = {IEEE},
Year = {2013},
Month = {January},
url = {http://dx.doi.org/10.1109/ICCCAS.2013.6765309},
Abstract = {The problem of designing the states of polarization (SOPs)
of the transmitter and receiver in clutter background via
target scattering estimation is discussed. Under the
assumption that the covariance of the clutter and noise is
known a prior, the Cramér-Rao lower bound (CRLB) for the
mean square error (MSE) of estimating the target is deduced.
The problem of the minimizing MSE is converted to be a
constrained optimization one. The paper solves this
constrained optimization problem to optimally design the
SOPs of the transmitter and the receiver. The performance of
the proposed method is compared with conventional ones.
Numerical results indicate that a significant amount of
power gain is achieved in the target scattering estimation
with the proposed method. © 2013 IEEE.},
Doi = {10.1109/ICCCAS.2013.6765309},
Key = {fds283496}
}
@article{fds283497,
Author = {Lei, S and Zhao, Z and Zhou, X and Nie, Z and Liu, QH},
Title = {Fast optimization method for polarization receiving based on
space mapping theory},
Journal = {2013 International Conference on Communications, Circuits
and Systems, Icccas 2013},
Volume = {2},
Pages = {156-160},
Publisher = {IEEE},
Year = {2013},
Month = {January},
url = {http://dx.doi.org/10.1109/ICCCAS.2013.6765308},
Abstract = {Aiming to solve the optimization problem of radar
polarimetry, a fast local search method (FLSM) is proposed
for bistatic case. The FLSM expedites searching speed of the
optimal polarization by restricting the optimal solution in
a local area. This local area is defined by the polarization
states with respect to the maximum and minimum polarization
receiving power (PRP). The performance of the FLSM is
validated by comparing with the three-step method (TSM).
Theoretical analyses indicate that the FLSM obtains the
optimal PRP by searching an area which, statistically, has
less than 25.26% searching area of the TSM. Numerical
experiments demonstrate that the proposed method obtains the
optimal polarization states more quickly and effectively
than the TSM. © 2013 IEEE.},
Doi = {10.1109/ICCCAS.2013.6765308},
Key = {fds283497}
}
@article{fds283499,
Author = {Xu, K and Zhang, Y and Wang, L and Yuan, M and Joines, WT and Liu,
QH},
Title = {Nano-scale memristor SPICE implementation using ideal
operational amplifier model},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {8911},
Publisher = {SPIE},
Year = {2013},
Month = {January},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.2034236},
Abstract = {The conception of memristor is becoming increasingly
prevalent due to its remarkable electronic properties. In
this paper, a circuit model of the memristor using simple
SPICE code is presented. An ideal closed-loop operational
amplifier (OP-AMP) is applied to realize the
feedback-controlled integrator, which expands the hitherto
methods to solve the memristor's modeling equations
presented by HP Lab. The behaviors of the proposed memristor
model in SPICE are investigated. The desired excitation
source and initial condition of the doped state can both be
easily tuned in the memristor model. Different pinched
hysteresis loop i-v curves are presented through different
stimulus like sinusoidal and square-wave voltage source. The
modeling results in SPICE are perfectly in good agreement
with the MATLAB calculated results, which verify the
feasibility of the proposed memristor model. © 2013
SPIE.},
Doi = {10.1117/12.2034236},
Key = {fds283499}
}
@article{fds283538,
Author = {Tan, T and Liu, QH},
Title = {Unconditionally stable ADI/Crank-Nicolson implementation and
lossy split error revisited},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {61},
Number = {11},
Pages = {5627-5636},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {January},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2013.2278857},
Abstract = {This paper first shows that the existing ADI and CN
dimplementations initiated by Namiki [1], [2] follows an
indirect way of solving a linear system. The ADI and CN
update equations can and should be implemented following the
standard FDTD formulation where the update equations
translate directly from Ampere's and Faraday's laws. The
advantages leading to a more complete lossy split error
analysis and possibilities of mitigating the numerical
errors are also presented. In high loss applications the CN
method greatly outperforms the ADI method in terms of
accuracy. The root cause of the ADI degradation is
discussed. © 2013 IEEE.},
Doi = {10.1109/TAP.2013.2278857},
Key = {fds283538}
}
@article{fds283539,
Author = {Ren, Q and Tobón, LE and Liu, QH},
Title = {A new 2D non-spurious discontinuous Galerkin Finite Element
Time Domain (DG-FETD) method for Maxwell's
equations},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {143},
Pages = {385-404},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13100901},
Abstract = {A new discontinuous Galerkin Finite Element Time Domain
(DG-FETD) method for Maxwell's equations is developed. It
can suppress spurious modes using basis functions based on
polynomials with the same order of interpolation for
electric field intensity and magnetic flux density (EB
scheme). Compared to FETD based on EH scheme, which reqires
different orders of interpolation polynomials for electric
and magnetic field intensities, this method uses fewer
unknowns and reduces the computation load. The discontinuous
Galerkin method is employed to implement domain
decomposition for the EB scheme based FETD. In addition, a
well-posed time-domain perfectly matched layer (PLM) is
extended to the EB scheme to simulate the unbounded problem.
Leap frog method is utilized for explicit time stepping.
Numerical results demonstrate that the above proposed
methods are effective and efficient for 2D time domain TMz
multi-domain problems.},
Doi = {10.2528/PIER13100901},
Key = {fds283539}
}
@article{fds283545,
Author = {Xu, K and Zhang, Y and Li, D and Fan, Y and Li, JLW and Joines, WT and Liu,
QH},
Title = {Novel design of a compact triple-band bandpass filter using
short stub-loaded sirs and embedded sirs
structure},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {142},
Pages = {309-320},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13080507},
Abstract = {A novel compact planar triple-band bandpass filter using two
sets of short stub-loaded stepped impedance resonators
(SSLSIRs) and a pair of embedded stepped impedance
resonators (ESIRs) has been proposed. The SSLSIRs can adjust
the bandwidths of the corresponding passbands over a wide
range, and the ESIRs employing non 0±-feed coupled
structure with mixed electric and magnetic coupling can
obtain an extra transmission zero. The embedded resonators
structure can further miniaturize the dimensions of the
whole triple-band filter. The operating frequencies of the
SSLSIRs and ESIRs are designed for the applications of the
WLAN (2.45/5.2 GHz) and WiMAX (3.5 GHz) systems,
respectively. The simulated and measured results are both
presented and show good agreement.},
Doi = {10.2528/PIER13080507},
Key = {fds283545}
}
@article{fds283546,
Author = {Wang, JG and Zhao, ZQ and Song, J and Nie, ZP and Liu,
QH},
Title = {Reconstruction of microwave absorption of multiple tumors in
heterogeneous tissue for microwave-induced thermo-acoustic
tomography},
Journal = {Progress in Electromagnetics Research M},
Volume = {32},
Pages = {57-72},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1937-8726},
url = {http://dx.doi.org/10.2528/PIERM13051903},
Abstract = {Time-of-flight (TOF) has been used to estimate sound
velocity (SV) distribution of heterogeneous tissue to
relieve the effect of acoustic heterogeneity in
microwave-induced thermo-acoustic tomography (MITAT).
Accurately picking the TOFs is significantly important to
ensure high accuracy SV images, which greatly help to
reconstruct the microwave absorption distribution
accurately. However, current methods for picking the TOFs
are designed for single source case. For breast tumor
detection in MITAT, these methods become ineffective or even
fail at the situation where multiple tumors are embedded in
a normal breast tissue. In order to accurately reconstruct
the microwave absorption properties of tumors in
heterogeneous tissue in MITAT, an efficient method for
picking tumors' TOFs is proposed. Combining the advantages
of the wavelet transform and Akaike information criterion
(AIC), the proposed method introduces a concept of separate
extraction of TOFs. It can efficiently and accurately pick
the TOFs of different tumors from the measured data in
MITAT. Using the TOFs picked by the proposed method can
efficiently help to reduce the effect of acoustic
heterogeneity and greatly improve the accuracy and the image
contrast of reconstructed microwave absorption properties.
Some numerical simulations are given to demonstrate the
effectiveness and feasibility of the proposed method in this
paper.},
Doi = {10.2528/PIERM13051903},
Key = {fds283546}
}
@article{fds283547,
Author = {Zheng, J and Su, T and Liu, QH and Zhang, L and Zhu,
W},
Title = {Fast parameter estimation algorithm for cubic phase signal
based on quantifying effects of doppler frequency
shift},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {142},
Pages = {57-74},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13061008},
Abstract = {For the chirp rate and its change rate estimation of cubic
phase signal (CPS), conventional algorithms cannot achieve a
trade-off between low computational cost and high
performance. In this paper, by utilizing the numerical
computational method (NCM), effects of Doppler frequency
shift are quantified, and the relationships of the optimal
signal length with the chirp rate and change rate of chirp
rate are obtained. Then a fast parameter estimation
algorithm (DMNUFFT), based on dechirp method (DM) and
nonuniform fast Fourier transform (NUFFT), is proposed.
Compared with existing algorithms, DMNUFFT can achieve high
performance with relatively low computational cost. The
performance analyses and an application to inverse synthetic
aperture radar (ISAR) imaging are shown to validate the
effectiveness of DMNUFFT.},
Doi = {10.2528/PIER13061008},
Key = {fds283547}
}
@article{fds283548,
Author = {Zhang, Y and Yuan, M and Liu, QH},
Title = {Ultra wide band response of an electromagnetic wave shield
based on a diode grid},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {141},
Pages = {591-605},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13053004},
Abstract = {This paper investigates Ultra Wide Band (UWB) response of a
self-actuated electromagnetic wave shield based on a diode
grid both in frequency and time domain. The investigation is
first carried out on a shield valid for an incident wave
polarized at a specific direction only, then extended to a
shield effective for an incident wave polarized at an
arbitrary direction. In the frequency domain, two linear
analysis methods are used to study the properties of the
diode grid over the frequency range from 0.01 to 10 GHz. One
method is the microwave network analysis. Another is
simulating the diode grid by a linear equivalent circuit
instead of a diode. In the time domain, the property of the
shield is studied with respect to a broadband impulse, where
the diode is described by its SPICE circuit model including
the nonlinear property. The results show that the diode grid
works well as a self-actuated electromagnetic power
selective surface (PSS) in a certain frequency range. The
diode grid is strongly frequency dependent. The operating
frequency band relies on the reactive elements in the diode
grid. In order to extend the operating frequency to a high
band, smaller cell size and smaller junction capacitance
should be employed.},
Doi = {10.2528/PIER13053004},
Key = {fds283548}
}
@article{fds283552,
Author = {Song, J and Zhao, ZQ and Wang, JG and Zhu, XZ and Wu, JN and Nie, ZP and Liu,
QH},
Title = {An integrated simulation approach and experimental research
on microwave induced thermo-acoustic tomography
system},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {140},
Pages = {385-400},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13041704},
Abstract = {Microwave induced thermo-acoustic tomography (MITAT) has
great potential in early breast cancer detection because it
utilizes the advantages of both microwave imaging and
ultrasound imaging. In this paper, a fast and efficient
simulation approach based on a hybrid method which combines
finite integration time domain (FITD) method and
pseudo-spectral time domain (PSTD) method is developed. By
using this approach, energy deposition of biology tissue
illuminated by electromagnetic fields can be accurately
simulated. Meanwhile, acoustic properties of the tissue can
be efficiently simulated as well. Based on this approach, a
MITAT model is created and some simulated results are
analyzed. Furthermore, some real breast tissues are adopted
to perform the thermo-acoustic imaging experiment.
Comparisons between experimental and simulated results are
made. The feasibility and effectiveness of the proposed
approach are demonstrated by both numerical simulations and
experimental results.},
Doi = {10.2528/PIER13041704},
Key = {fds283552}
}
@article{fds283553,
Author = {Yang, K and Zhao, Z and Liu, QH},
Title = {Robust adaptive beamforming against array calibration
errors},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {140},
Pages = {341-351},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER13042203},
Abstract = {Adaptive beamforming methods degrade in the presence of
model mismatch. In this paper, we develop a modified
interference covariance matrix reconstruction based
beamformer that is robust against large array calibration
errors. The calibration errors can come from the element
position errors, and/or amplitude and phase errors, etc. The
proposed method is based on the fact that the sample
covariance matrix can approximate the interference
covariance matrix properly when the desired signal is small,
and a reconstructed covariance matrix based on the Capon
spectral will be better than the sample covariance matrix
when the desired signal is large. A weighted summation of
two covariance matrices in references is used to reconstruct
the interference covariance matrix. Moreover, a
computationally efficient convex optimization-based
algorithm is used to estimate the mismatch of the steering
vector associated with the desired signal. Several
simulation cases are applied to show the superiority of the
proposed method over other robust adaptive
beamformers.},
Doi = {10.2528/PIER13042203},
Key = {fds283553}
}
@article{fds283566,
Author = {Liu, QH and Jiang, L and Chew, WC},
Title = {Large-scale electromagnetic computation for modeling and
applications},
Journal = {Proceedings of the Ieee},
Volume = {101},
Number = {2},
Pages = {223-226},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {January},
ISSN = {0018-9219},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000313724400002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {The papers in this special issue are devoted to the topic of
large-scale electromagnetic computation methods for modeling
and applicatoins. © 1963-2012 IEEE.},
Doi = {10.1109/JPROC.2012.2232512},
Key = {fds283566}
}
@article{fds283567,
Author = {Yang, K and Zhao, Z and Liu, QH},
Title = {Fast pencil beam pattern synthesis of large unequally spaced
antenna arrays},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {61},
Number = {2},
Pages = {627-634},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {January},
ISSN = {0018-926X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000314681200016&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Reducing the computational cost of large array pattern
synthesis is attractive in many applications. In this paper,
a fast pencil beam pattern synthesis method for large
nonuniform antenna arrays is proposed. This method is based
on an interpolation in a least square sense and iterative
fast Fourier transform (FFT), i.e., interpolate the
nonuniform distributed elements into uniform virtual
elements, and then apply FFT to synthesis the uniform array.
Thanks to the efficiency of FFT, the proposed method is much
faster and can handle much larger arrays than the existing
methods. To guarantee the interpolation accuracy, the choice
of the interpolation parameters is discussed. Both linear
and planar nonuniform array examples are shown to validate
the advantages of the proposed method. © 2012
IEEE.},
Doi = {10.1109/TAP.2012.2220319},
Key = {fds283567}
}
@article{fds283568,
Author = {Zhao, Z and Song, J and Zhu, X and Wang, J and Wu, J and Liu, Y and Nie, Z and Liu, Q},
Title = {System development of microwave induced thermo-acoustic
tomography and experiments on breast tumor},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {134},
Pages = {323-336},
Publisher = {EMW Publishing},
Year = {2013},
Month = {January},
ISSN = {1559-8985},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312383200018&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {Microwave induced thermo-acoustic tomography (MI- TAT) has
become a keen research topic in recent years due to its
great potential in early breast cancer detection. A secure
and accurate MI- TAT system has been established. Some
experiments have been made to demonstrate the performance of
the MITAT system. Based on an experiment using phantom, some
quantitative features of the system have been obtained. Some
imaging experiments with real human breast cancer tissues
are performed to demonstrate its effectiveness and the
potential in clinical diagnosis. Images with both high
contrast and fine spatial resolution are achieved by using
time reversal mirror (TRM) technique in the imaging
processing. Moreover, comparisons between the MITAT system
result and an ultrasound imaging system result are made.
From the comparison, the MITAT system shows its advantages
of better contrast over the ultrasound imaging system. The
system and the experiments in this paper verify the
mechanism of MITAT for breast cancer detection and provide a
prototype basis for clinical practice. © 2010 EMW
Publishing. All Rights Reserved.},
Doi = {10.2528/PIER12101604},
Key = {fds283568}
}
@article{fds283569,
Author = {Wu, J and Zhao, Z and Nie, Z and Liu, QH},
Title = {A broadband unidirectional antenna based on closely spaced
loading method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {61},
Number = {1},
Pages = {109-116},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {January},
ISSN = {0018-926X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000312996000013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In order to achieve broadband and unidirectional radiation,
a planar printed antenna based on closely spaced loading
method is proposed and fabricated. This antenna consists of
a printed rectangular loop with two gaps and a metallic
strip. The rectangular loop has a good direction but has a
drawback of narrow band. According to the closely spaced
loading theory, the impedance at the upper frequency will
decrease when a metallic strip is placed at the maximum
radiation direction of the rectangular loop. This improves
the impedance matching. A new resonant frequency point is
induced. Meanwhile, the resonant frequency point can be
changed by modifying the length of the metallic strip. The
impedance matching between the two resonant peaks (One peak
is determined by the rectangular loop, the other is
determined by the metallic strip) is improved by changing
the length and the position of the metallic strip. Thus the
impedance bandwidth is greatly expanded. Experimental
results show good performance of the proposed antenna. It
has a 40.7% measured bandwidth, ranging from 2.29 to 3.46
GHz. The measured front-to-back (F/B) ratio of the proposed
antenna is larger than 10 dB in the whole frequency band. ©
1963-2012 IEEE.},
Doi = {10.1109/TAP.2012.2216492},
Key = {fds283569}
}
@article{fds283762,
Author = {Luo, M and Lin, Y and Liu, QH},
Title = {Spectral methods and domain decomposition for nanophotonic
applications},
Journal = {Proceedings of the Ieee},
Volume = {101},
Number = {2},
Pages = {473-483},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {January},
ISSN = {0018-9219},
url = {http://dx.doi.org/10.1109/JPROC.2012.2218791},
Abstract = {Nanophotonic applications often involve large-scale problems
with excessive demand on computational resources. We develop
a domain decomposition method (DDM) to reduce computer
memory and central processing unit (CPU) time requirements
by combining the spectral element method (SEM) and the
spectral integral method (SIM) for large-scale finite
periodic structures. The interior scattering subdomains
within each period are modeled by the SEM while the exterior
scattering problem is modeled by the SIM. The interactions
between neighboring subdomains are modeled by the
frequency-domain version of the Riemann solver. Numerical
convergence of the Riemann solver is fast and weakly
dependent on the size of the system. Two sets of examples
demonstrate the typical nanophotonic applications: The first
periodic system is a vertical coupling waveguide based on a
photonic crystal slab which opens a way to construct and
simulate optical circuits. The second periodic system is a
finite-sized metamaterial with an effective negative
refractive index, whose edge effects are visualized and
analyzed. © 1963-2012 IEEE.},
Doi = {10.1109/JPROC.2012.2218791},
Key = {fds283762}
}
@article{fds283764,
Author = {Chen, J and Liu, QH},
Title = {Discontinuous Galerkin time-domain methods for multiscale
electromagnetic simulations: A review},
Journal = {Proceedings of the Ieee},
Volume = {101},
Number = {2},
Pages = {242-254},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2013},
Month = {January},
ISSN = {0018-9219},
url = {http://dx.doi.org/10.1109/JPROC.2012.2219031},
Abstract = {Efficient multiscale electromagnetic simulations require
several major challenges that need to be addressed, such as
flexible and robust geometric modeling schemes, efficient
and stable time-stepping methods, etc. Due to the versatile
choices of spatial discretization and temporal integration,
discontinuous Galerkin time-domain (DGTD) methods can be
very promising in simulating transient multiscale problems.
This paper provides a comprehensive review of different DGTD
schemes, highlighting the fundamental issues arising in each
step of constructing a DGTD system. The issues discussed
include the selection of governing equations for transient
electromagnetic analysis, different basis functions for
spatial discretization, as well as the implementation of
different time-stepping schemes. Numerical examples
demonstrate the advantages of DGTD for multiscale
electromagnetic simulations. © 1963-2012
IEEE.},
Doi = {10.1109/JPROC.2012.2219031},
Key = {fds283764}
}
@article{fds283537,
Author = {Liu, Y and Liu, QH},
Title = {Combining triangle Gaussian integration and modified NUFFT
for evaluating two-dimensional Fourier transform
integrals},
Journal = {Aeu International Journal of Electronics and
Communications},
Volume = {68},
Number = {3},
Pages = {254-259},
Publisher = {Elsevier BV},
Year = {2013},
ISSN = {1434-8411},
url = {http://dx.doi.org/10.1016/j.aeue.2013.09.007},
Doi = {10.1016/j.aeue.2013.09.007},
Key = {fds283537}
}
@article{fds283551,
Author = {Xu, KD and Zhangi, YH and Yang, Y and Joines, WT and Liu, QH and Fan,
Y},
Title = {A tri-mode bandpass filter using capacitive and inductive
source-load coupling},
Journal = {Microwave Journal},
Volume = {56},
Number = {5},
Pages = {178-188},
Year = {2013},
ISSN = {0192-6225},
Abstract = {This article presents a compact microstrip bandpass filter
(BPF), which consists of a circular tri-mode resonator
(CTMR) and two meandering feed lines with both capacitive
and inductive S-L couplings to obtain good harmonic
suppression and multiple transmission zeros. A prototype of
the proposed BPF, centered at 4.1 GHz, has been designed and
fabricated. The measured results are in good agreement with
the full-wave simulated ones.},
Key = {fds283551}
}
@article{fds283757,
Author = {Zhang, W and Liu, QH and Hoorfar, A},
Title = {Three-dimensional imaging of targets behind multilayered
walls},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2012},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2012.6347969},
Abstract = {A three-dimensional (3D) beamformer for through-the-wall
radar imaging (TWI) for a general multilayered wall case is
presented. The far field layered medium Green's function is
incorporated in the 3D TWI algorithm for the compensation of
the wall effect. Numerical results show that the 3D
beamformer can provide high quality focused image of the
target behind the walls. © 2012 IEEE.},
Doi = {10.1109/APS.2012.6347969},
Key = {fds283757}
}
@article{fds283761,
Author = {Zhang, W and Liu, QH and Hoorfar, A},
Title = {Three-dimensional real-time through-the-wall
imaging},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2012},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2012.6348544},
Abstract = {In this paper a three-dimensional (3D) diffraction
tomographic (DT) algorithm is proposed for real-time
through-the-wall imaging (TWI). The spectral expansion of
the three-layered medium dyadic Green's function is employed
to derive a linear relation between the spatial Fourier
transforms of the image and the scattered field. Then the
image is efficiently reconstructed with inverse Fast Fourier
Transform (IFFT). The linearization of the inversion scheme
with Born approximation and the easy implementation of the
algorithm with FFT/IFFT make the DT algorithm suitable for
on-site TWI applications. © 2012 IEEE.},
Doi = {10.1109/APS.2012.6348544},
Key = {fds283761}
}
@article{fds283556,
Author = {Wang, JG and Zhao, ZQ and Zhu, XZ and Song, J and Nie, ZP and Liu,
QH},
Title = {Compressed sensing in microwave induced thermo-acoustic
tomography},
Journal = {2012 International Conference on Computational Problem
Solving, Iccp 2012},
Pages = {310-314},
Publisher = {IEEE},
Year = {2012},
Month = {December},
url = {http://dx.doi.org/10.1109/ICCPS.2012.6384223},
Abstract = {Aiming to reliably reconstruct an image with fewer
measurements, we adapt compressed sensing (CS) in microwave
induced thermo-acoustic tomography (MITAT). Most of current
existing reconstruction algorithms for MITAT employ circular
detection and require a great deal of measurements, which
imply long acquisition times. In this paper, CS is
implemented to reconstruct an image of electromagnetic
absorption distribution with fewer numbers of detection
angles and Fourier samples by using gradient projection for
sparse reconstruction (GPSR) algorithm. Some numerical
simulation experiments are given to demonstrate the
excellent performance of CS in MITAT. © 2012
IEEE.},
Doi = {10.1109/ICCPS.2012.6384223},
Key = {fds283556}
}
@article{fds283563,
Author = {Li, X and Liu, QH and Yang, K},
Title = {IPRM algorithm employed to remove Gibbs phenomenon in
F-PSTD},
Journal = {2012 10th International Symposium on Antennas, Propagation
and Em Theory, Isape 2012},
Pages = {1033-1036},
Publisher = {IEEE},
Year = {2012},
Month = {December},
url = {http://dx.doi.org/10.1109/ISAPE.2012.6408951},
Abstract = {The Inverse Polynomial Reconstruction Method (IPRM) is
employed to perform post-processing to removed possible
Gibbs phenomenon in Fourier pseudo-spectral timedomain
(F-PSTD) simulation. Compared with the Gegenbauer
reconstruction, the IPRM is preferable for its simplicity
and accuracy in reconstruction. Thus the IPRM is employed to
do post-processing on F-PSTD fields for the first time so
far as we know. The results are compared with those of
finite-difference time-domain (FDTD) with the same settings,
and a good coincidence is found. This shows the feasibility,
simplicity and accuracy to use IPRM to do post-processing of
fields by F-PSTD. © 2012 IEEE.},
Doi = {10.1109/ISAPE.2012.6408951},
Key = {fds283563}
}
@article{fds283571,
Author = {Yang, K and Zhao, Z and Liu, QH},
Title = {An iterative FFT based flat-top footprint pattern synthesis
method with planar array},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {26},
Number = {14-15},
Pages = {1956-1966},
Publisher = {Informa UK Limited},
Year = {2012},
Month = {December},
ISSN = {0920-5071},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000309127700018&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {A pattern synthesis technique for the flat-top pattern with
an arbitrary footprint is proposed in this paper. This
technique is based on an iterative fast Fourier transform
(FFT) method and the Elliott-Stern method. Due to the
Fourier transformation-pair relationship between the array
excitations and the array factor, the iterative FFT method
is used to adjust the array factor iteratively to obtain the
desired pattern. To accelerate this method and to make this
method more robust, the initial element excitations are
obtained by applying Fourier transform to a pattern designed
by the Elliott-Stern method. Several numerical simulations
are applied to validate the effectiveness of this technique.
© 2012 Taylor & Francis.},
Doi = {10.1080/09205071.2012.722752},
Key = {fds283571}
}
@article{fds283572,
Author = {Xu, KD and Zhang, YH and Fan, Y and Joines, WT and Liu,
QH},
Title = {Novel circular dual-mode filter with both capacitive and
inductive source-load coupling for multiple transmission
zeros},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {26},
Number = {13},
Pages = {1675-1684},
Publisher = {Informa UK Limited},
Year = {2012},
Month = {December},
ISSN = {0920-5071},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000308106300002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In this paper, a novel miniaturized bandpass filter (BPF)
using a circular dual-mode resonator with both capacitive
source-load (S-L) coupling and inductive S-L coupling is
presented for the first time. The proposed filter consists
of a circular open stub-loaded dual-mode resonator and two
meandering feed lines with both capacitive and inductive S-L
coupling to obtain seven transmission zeros and good
harmonic suppression. Compared with the other two BPFs using
two conventional feeding styles, i.e. only capacitive S-L
coupling and only inductive S-L coupling, this type of BPF
can not only possess a dual-mode response, but also generate
more transmission zeros to suppress an undesired harmonic
passband. Moreover, the transmission zeros can be also
controllable to meet the required filter selectivity. The
simulated and measured results are presented and show good
agreement. © 2012 Taylor & Francis.},
Doi = {10.1080/09205071.2012.708966},
Key = {fds283572}
}
@article{fds283763,
Author = {Zhu, B and Chen, J and Zhong, W and Liu, QH},
Title = {Analysis of photonic crystals using the hybrid
finite-element/finite-difference time domain technique based
on the discontinuous Galerkin method},
Journal = {International Journal for Numerical Methods in
Engineering},
Volume = {92},
Number = {5},
Pages = {495-506},
Publisher = {WILEY},
Year = {2012},
Month = {November},
ISSN = {0029-5981},
url = {http://dx.doi.org/10.1002/nme.4348},
Abstract = {Two-dimensional photonic crystal structures are analyzed by
a recently developed hybrid technique combining the
finite-element time-domain (FETD) method and the
finite-difference time-domain (FDTD) method. This hybrid
FETD/FDTD method uses the discontinuous Galerkin method as
framework for domain decomposition. To the best of our
knowledge, this is the first hybrid FETD/FDTD method that
allows non-conformal meshes between different FETD and FDTD
subdomains. It is also highly parallelizable. These
properties are very suitable for the computation of periodic
structures with curved surfaces. Numerical examples for the
computation of the scattering parameters of two-dimensional
photonic bandgap structures are presented as applications of
the hybrid FETD/FDTD method. Numerical results demonstrate
the efficiency and accuracy of the proposed hybrid method.
© 2012 John Wiley & Sons, Ltd.},
Doi = {10.1002/nme.4348},
Key = {fds283763}
}
@article{fds283754,
Author = {Deng, JH and Wang, L and Liu, QH},
Title = {A macromodel of memristor using symbolically defined
devices},
Journal = {Applied Mechanics and Materials},
Volume = {195-196},
Pages = {245-248},
Publisher = {Trans Tech Publications},
Year = {2012},
Month = {October},
ISSN = {1660-9336},
url = {http://dx.doi.org/10.4028/www.scientific.net/AMM.195-196.245},
Abstract = {A macromodel of the prototype of memristor is developed in
Advance Design System software (ADS) by using symbolically
defined devices (SDDs). This model can simulate the
electrical behaviors of a memristor. It is shown that the
presented macromodel meets the requirements for simulations
of application circuits. © (2012) Trans Tech Publications,
Switzerland.},
Doi = {10.4028/www.scientific.net/AMM.195-196.245},
Key = {fds283754}
}
@article{fds283758,
Author = {Chen, G and Zhao, Z and Liu, QH},
Title = {The computational study of microwave-induced thermo-acoustic
tomography for biologic tissue imaging based on
pseudo-spectrum time domain and time reversal mirror
technique},
Journal = {Applied Mechanics and Materials},
Volume = {195-196},
Pages = {353-359},
Publisher = {Trans Tech Publications},
Year = {2012},
Month = {October},
ISSN = {1660-9336},
url = {http://dx.doi.org/10.4028/www.scientific.net/AMM.195-196.353},
Abstract = {Microwave-Induced Thermo-Acoustic Tomography (MITAT) own
much concerns in recent years in biomedical imaging field.
High contrast and resolution compared with conventional
microwave or ultrasound imaging system especially for
malignant tumors are outstanding characters of it. In this
paper, the induced thermo-acoustic wave propagating in a
mimic biologic tissue is simulated by numeric method
Pseudo-Spectrum Time Domain (PSTD). Due to the excellent
performance in noise-depress and the stability for the
fluctuation of the model parameters, Time Reversal Mirror
(TRM) imaging technique is studied computationally for the
simulative received thermo-acoustic signals. Some
thermo-acoustic objects with different initial pressure
distribution are designed and imaged by TRM technique to
represent the complex biologic tissue case in a random
media. The quality of images generated by TRM technique
based on PSTD method hints the potential of the MITAT
technique. © (2012) Trans Tech Publications,
Switzerland.},
Doi = {10.4028/www.scientific.net/AMM.195-196.353},
Key = {fds283758}
}
@article{fds283760,
Author = {Zhu, B and Chen, J and Zhong, W and Liu, QH},
Title = {A hybrid finite-element/finite-difference method with an
implicit-explicit time-stepping scheme for Maxwell's
equations},
Journal = {International Journal of Numerical Modelling: Electronic
Networks, Devices and Fields},
Volume = {25},
Number = {5-6},
Pages = {607-620},
Publisher = {WILEY},
Year = {2012},
Month = {September},
ISSN = {0894-3370},
url = {http://dx.doi.org/10.1002/jnm.1853},
Abstract = {This paper describes a hybrid technique in time domain that
combines the explicit finite-difference time-domain (FDTD)
method and the implicit finite-element time-domain (FETD)
method based on the discontinuous Galerkin method to analyze
transient electromagnetic problems. In the hybrid method,
the FETD part uses the unconditionally stable
Crank-Nicholson method with a triangular mesh, whereas the
standard FDTD part employs a staggered Cartesian grid for
spatial discretization and the leap-frog scheme for time
stepping. Nonconforming meshes are allowed between the
structured FDTD grid and unstructured FETD meshes. The
hybrid method takes advantages of the modeling flexibility
of the FETD method for complex structures and the efficiency
of the FDTD method for simple structures. The hybrid
implicit-explicit time-stepping scheme allows a time-step
increment as large as the stability limit for the FDTD
method, which can be much larger than the stability
criterion of the explicit FETD scheme with small elements.
The hybrid scheme has second-order accuracy. Numerical
examples demonstrate the efficiency of the proposed method.
Copyright © 2012 John Wiley & Sons, Ltd.},
Doi = {10.1002/jnm.1853},
Key = {fds283760}
}
@article{fds283562,
Author = {Wu, JN and Zhao, ZQ and Liu, JZ and Nie, ZP and Liu,
QH},
Title = {A compact linear tapered slot antenna with integrated balun
for UWB applications},
Journal = {Progress in Electromagnetics Research C},
Volume = {29},
Pages = {163-176},
Publisher = {EMW Publishing},
Year = {2012},
Month = {July},
ISSN = {1937-8718},
url = {http://dx.doi.org/10.2528/PIERC12031204},
Abstract = {A compact linear tapered slot antenna with wideband
performance is proposed. The antenna consists of a
microstrip to slotline transition and a linear tapered slot
structure which is connected to the slotline. Due to the
linear tapered slot, the antenna can realize unidirectional
radiation in wideband band. The microstrip to slotline
transition is implemented by using a tapered cross, which
can easily obtain impedance transformation. Furthermore,
this transition can be realized with a small size. The
antenna is fabricated and optimized numerically. Both
simulated and measured results validate the performance of
the antenna in frequency and time domains. The results show
that the antenna achieves a bandwidth up to 118% from
2.6-10.1 GHz. The simulated time domain response of the
antenna also shows its good performance in time-domain. The
antenna can be well applied to ultra-wideband
system.},
Doi = {10.2528/PIERC12031204},
Key = {fds283562}
}
@article{fds341113,
Author = {Cai, GX and Cai, ZP and Xu, HY and Luo, M and Liu, QH},
Title = {A Slot-Based Surface Plasmon-Polariton Waveguide with
Long-Range Propagation and Superconfinement},
Journal = {Ieee Photonics Journal},
Volume = {4},
Number = {3},
Pages = {844-855},
Year = {2012},
Month = {June},
url = {http://dx.doi.org/10.1109/JPHOT.2012.2198914},
Abstract = {A full-vector spectral element method (SEM) is applied to
model and simulate surface plasmon-polariton (SPP)
waveguides. Gauss-Lobatto-Legendre (GLL) polynomials are
used to construct higher-order basis functions to achieve
spectral accuracy. A discretization scheme featuring a
nonuniform mesh with extra elements near the
metal-dielectric interface is proposed to capture the
waveguide configuration and dramatical mode field variations
of the SPP waveguide. The studies on the accuracy and mode
field distribution show that SEM is highly efficient and
accurate. Using SEM simulation, a slot-based SPP waveguide
operating at telecom wavelengths is proposed. Numerical
results show that the proposed structure can simultaneously
achieve millimeter-scale propagation distance (Lp ~ 2.6 mm)
and below-diffraction-limited effective mode area (Aeff/A0 ~
0.3). Parametric plots illustrate a significant improvement
when compared to conventional SPP waveguides. Investigation
of the mode width and crosstalk also demonstrates the
excellent 3-D integration performance of the structure. The
proposed slot-based SPP waveguide thus can become a
potential candidate for highly integrated photonic circuits.
© 2012 IEEE},
Doi = {10.1109/JPHOT.2012.2198914},
Key = {fds341113}
}
@article{fds283752,
Author = {He, Z and Zhao, Z and Nie, Z and Ma, P and Liu, QH},
Title = {Resolving manifold ambiguities for sparse array using planar
substrates},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {60},
Number = {5},
Pages = {2558-2562},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2012},
Month = {May},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2012.2189722},
Abstract = {Aiming to resolve the manifold ambiguities for sparse
arrays, a method based on the multiple signal classification
(MUSIC) algorithm using planar substrate is proposed. The
main reason for spurious MUSIC spectrum is that the steering
vector of spurious direction of arrival (DOA) is a linear
combination of the steering vectors of true DOAs. The main
idea of the proposed method is to add some planar substrates
at the front-ends of the elements of an array. The
refractive indices and thicknesses of the substrates can be
different from each other. This treatment breaks down the
linearity which induces the ambiguity of a sparse array.
Because the equivalent positions of the elements change for
different DOAs after adding the substrates on the array, the
spurious peaks will disappear or not overlap on the old
peaks. Nevertheless the peaks of the true directions will
remain. The spurious peaks can be discriminated according to
this feature. Simulation results demonstrate the
effectiveness and the feasibility of the method. Meanwhile
the simulation results also show that the proposed method
can partially resolve the trivial ambiguities even if the
true DOA and the spurious DOA are confined to [0°, 180°).
© 2012 IEEE.},
Doi = {10.1109/TAP.2012.2189722},
Key = {fds283752}
}
@article{fds283570,
Author = {Yang, K and Zhao, Z and Ouyang, J and Nie, Z and Liu,
QH},
Title = {Optimisation method on conformal array element positions for
low sidelobe pattern synthesis},
Journal = {Iet Microwaves, Antennas & Propagation},
Volume = {6},
Number = {6},
Pages = {646-652},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2012},
Month = {April},
ISSN = {1751-8725},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000305151400006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {An optimisation method for antenna element positions in
conformal arrays is proposed in this study. Owing to the
platform effect, the element pattern in a conformal array
varies with its location. It is usually very time consuming
to simulate the element patterns at all possible locations.
In this proposed method, the patterns of an element located
at an arbitrary position on the platform are obtained by
interpolating the element patterns at several sampled
locations using the model-based parameter estimation (MBPE)
method. This interpolation strategy consists of two steps.
Firstly, it interpolates the Fourier coefficients of the
given element patterns at the sampled locations to acquire
the Fourier coefficients of the element patterns at the
desired location. Then the inverse discrete Fourier
transform (IDFT) or the inverse fast Fourier transform
(IFFT) algorithm is applied to obtain the element pattern.
Compared with the conventional interpolation methods, this
interpolation needs much fewer samples in the spatial domain
and a smaller number of interpolation parameters. The
element layout is optimised by the particle swarm
optimisation (PSO) method. For each layout, the array
excitations are obtained by the robust convex optimisation
method. This proposed method is demonstrated through an
optimisation on a cylindrical-parabolic conformal array. ©
2012 The Institution of Engineering and Technology.},
Doi = {10.1049/iet-map.2011.0330},
Key = {fds283570}
}
@article{fds283759,
Author = {He, Z and Zhao, Z and Nie, Z and Tang, P and Wang, J and Liu,
QH},
Title = {Method of solving ambiguity for sparse array via power
estimation based on MUSIC algorithm},
Journal = {Signal Processing},
Volume = {92},
Number = {2},
Pages = {542-546},
Publisher = {Elsevier BV},
Year = {2012},
Month = {February},
ISSN = {0165-1684},
url = {http://dx.doi.org/10.1016/j.sigpro.2011.08.020},
Abstract = {Sparse linear arrays provide better performance than the
filled linear arrays in terms of direction estimation and
resolution with reduced size and low cost. However, they are
subject to manifold ambiguity. A method based on the
Multiple Signal Classification (MUSIC) algorithm to solve
the manifold ambiguity of uncorrelated sources for sparse
array is proposed in this paper. The method consists of two
steps. The first step is to obtain all the directions of
arrivals (DOAs), including true and spurious DOAs, using
traditional MUSIC. The second step is to estimate the power
values of the all DOAs by substituting all the DOAs to a
cost function. The well-known Davidson Fletcher Powell (DFP)
and Broyden Fletcher Goldfarb Shanno (BFGS) algorithms are
used to estimate the power values. The power values of
spurious DOAs are very small or tend to zero compared with
the values of the true DOAs. The true DOAs are then
discriminated easily from the spurious DOAs with the power
values. Simulation results demonstrate the effectiveness and
the feasibility of the method. © 2011 Elsevier B.V. All
Rights Reserved.},
Doi = {10.1016/j.sigpro.2011.08.020},
Key = {fds283759}
}
@article{fds283534,
Author = {Wu, J and Li, Z and Huang, Y and Liu, Q and Yang, J},
Title = {Processing one-stationary bistatic SAR data using inverse
scaled Fourier transform},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {129},
Pages = {143-159},
Publisher = {EMW Publishing},
Year = {2012},
Month = {January},
ISSN = {1559-8985},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000306596700009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In bistatic synthetic aperture radar (SAR) with one
stationary station, two-dimensional spatial variance is a
major problem which should be handled. In this paper, an
Inverse Scaled Fourier Transform (ISFT) imaging algorithm to
deal with this problem is proposed. The approach linearizes
the two-dimensional spatiallyvariant point target reference
spectrum to derive the reflectivity pattern's spectrum.
Based on this spectrum, an ISFT along range direction and a
frequency shift along azimuth direction are used to achieve
the two-dimensional spatial variance correction. This method
is efficient as it only uses phase multiplication and FFTs.
Numerical simulations verified the effectiveness of the
method.},
Doi = {10.2528/PIER12021506},
Key = {fds283534}
}
@article{fds283555,
Author = {Zhu, X and Zhao, Z and Yang, K and Nie, Z and Liu, Q},
Title = {A prototype system of microwave induced thermo-acoustic
tomography for breast tumor.},
Journal = {Annual International Conference of the Ieee Engineering in
Medicine and Biology Society. Ieee Engineering in Medicine
and Biology Society. Annual International
Conference},
Volume = {2012},
Pages = {464-467},
Year = {2012},
Month = {January},
ISSN = {1557-170X},
url = {http://dx.doi.org/10.1109/embc.2012.6345968},
Abstract = {Microwave-induced thermo-acoustic tomography (MITAT) is an
innovative technique for tumor's detection. Due to there has
high contrast in terms with permittivity and electrical
conductivity of tumor versus normal tissue, even if the
tumor still in the early phase it can be imaged clearly. For
the proposed MITAT system, low energy microwave pulses are
used as the irradiating signals, while the received signals
are ultrasound, high contrast and high resolution images can
be obtained. After some theoretical research and basic
fundamental experiments, the first prototype of experimental
system is designed and built. It includes the microwave
radiator, the arrayed sensor bowl, the circular scanning
platform, the system controller and the signal processor.
Based on the experimental results using this integral MITAT
clinic system, the images contrast can be reached higher
than 383:1; while the sub-millimeter special resolution is
obtained for a 1cm(3) scale tumor mimic.},
Doi = {10.1109/embc.2012.6345968},
Key = {fds283555}
}
@article{fds283750,
Author = {Liu, Z and Liu, QH and Zhu, CH and Yang, JY},
Title = {A fast inverse polynomial reconstruction method based on
conformal fourier transformation},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {122},
Pages = {119-136},
Publisher = {EMW Publishing},
Year = {2012},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER11092008},
Abstract = {A fast Inverse Polynomial Reconstruction Method (IPRM) is
proposed to efficiently eliminate the Gibbs phenomenon in
Fourier reconstruction of discontinuous functions. The
framework of the fast IPRM is modified by reconstructing the
function in discretized elements, then the Conformal Fourier
Transform (CFT) and the Chirp Z-Transform (CZT) algorithms
are applied to accelerate the evaluation of reconstruction
coefficients. The memory cost of the fast IPRM is also
significantly reduced, owing to the transformation matrix
being discretized in the modified framework. The computation
complexity and memory cost of the fast IPRM are O(MN log 2L)
and O(MN), respectively, where L is the number of the
discretized elements, M is the degree of polynomials for the
reconstruction of each element, and N is the number of the
Fourier series. Numerical results demonstrate that the fast
IPRM method not only inherits the robustness of the
Generalized IPRM (G-IPRM) method, but also significantly
reduces the computation time and the memory cost. Therefore,
the fast IPRM method is useful for the pseudospectral time
domain methods and for the volume integral equation of the
discontinuous material distributions.},
Doi = {10.2528/PIER11092008},
Key = {fds283750}
}
@article{fds283753,
Author = {Peng, Y and Liu, QH},
Title = {Spiral MRI reconstruction based on table-lookup
gridding},
Journal = {Lecture Notes in Electrical Engineering},
Volume = {154 LNEE},
Pages = {339-345},
Publisher = {Springer London},
Year = {2012},
Month = {January},
ISSN = {1876-1100},
url = {http://dx.doi.org/10.1007/978-1-4471-2386-6_44},
Abstract = {Since spiral encoding is often performed for fast data
acquisition in magnetic resonance image (MRI), the MRI
images can be reconstructed by taking inverse Fourier
transform of the sampled MRI data in k-space. Therefore,
nonuniform inverse Fourier transform have been widely used
in MRI reconstruction. © 2012 Springer-Verlag London
Limited.},
Doi = {10.1007/978-1-4471-2386-6_44},
Key = {fds283753}
}
@article{fds283755,
Author = {Wang, JG and Zhao, ZQ and Song, J and Zhu, XZ and Nie, ZP and Liu,
QH},
Title = {Reconstruction of microwave absorption properties in
heterogeneous tissue for microwave-induced thermo-acoustic
tomography},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {130},
Pages = {225-240},
Year = {2012},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER12062704},
Abstract = {Aiming to efficiently overcome the acoustic refraction and
accurately reconstruct the microwave absorption properties
in heterogeneous tissue, an iterative reconstruction method
is proposed for microwave-induced thermo-acoustic tomography
(MITAT) system. Most current imaging methods in MITAT assume
that the heterogeneous sound velocity (SV) distribution
obeys a simple Gaussian distribution. In real problem, the
biological tissue may have several different inclusions with
different SV distribution. In this case, the acoustic
refraction must be taken into account. The proposed
iterative method is consisted of an iterative engine with
time reversal mirror (TRM), fast marching method (FMM) and
simultaneous algebraic reconstruction technique (SART). This
method utilizes TRM, FMM and SART to estimate the SV
distribution of tissue to solve the phase distortion problem
caused by the acoustic refraction effect and needs little
prior knowledge of the tissue. The proposed method has great
advantages in both spatial resolution and contrast for
imaging tumors in acoustically heterogeneous medium. Some
numerical simulation results are given to demonstrate the
excellent performance of the proposed method.},
Doi = {10.2528/PIER12062704},
Key = {fds283755}
}
@article{fds283756,
Author = {Song, J and Zhao, ZQ and Wang, JG and Zhu, XZ and Wu, JN and Liu, YL and Liu,
QH},
Title = {An image correction method based on elec-tromagnetic
simulation for microwave in-duced thermo-acoustic tomography
system},
Journal = {Progress in Electromagnetics Research B. Pier
B},
Volume = {43},
Number = {43},
Pages = {19-33},
Publisher = {EMW Publishing},
Year = {2012},
Month = {January},
ISSN = {1937-6472},
url = {http://dx.doi.org/10.2528/PIERB12070215},
Abstract = {In microwave induced thermo-acoustic tomography (MI-TAT)
system, radiation of an antenna is a near -eld problem which
gives rise to a non-uniform distribution of microwave
radiation power in detection area. Due to this non-uniform
distribution, the contrast of MITAT image which is
proportional to the absorbed microwave en-ergy will not
reoect the real characteristics (dielectric properties) of
biological tissues. In this paper, an image correction
method based on electromagnetic simulation is proposed to
correct the image contrast a®ected by the non-uniform
microwave radiation distribution. First, the distribution of
the microwave radiation power is simulated through a
numerical simulation framework. Conventional time-reversal
mir-ror (TRM) technique is applied to reconstruct the image.
Then the microwave power distribution is applied to correct
the image. The method is numerically demonstrated. The two
samples with the same microwave absorption property and with
di®erent microwave absorp-tion properties are
experimentally investigated. Both numerical simu-lations and
experimental results demonstrate the good performance of the
proposed method.},
Doi = {10.2528/PIERB12070215},
Key = {fds283756}
}
@article{fds283741,
Author = {Ahmed, I and Li, EP and Liu, QH},
Title = {Development of an novel approach for the simulation of
nanodevices using FDTD},
Journal = {Iet Conference Publications},
Volume = {2011},
Number = {577 CP},
Pages = {194-195},
Publisher = {IET},
Year = {2011},
Month = {December},
url = {http://dx.doi.org/10.1049/cp.2011.0098},
Abstract = {A new way for the simulation of nano-devices is presented,
which consists of Schrodinger's equation, time dependent
scalar and vector potential equations derived from Maxwell's
equations using Lorenz gauge. For analysis the finite
difference time domain (FDTD) method is applied to these
equations. To validate the method a two-dimensional
semiconductor nanocavity is considered and numerical results
are compared with those of the analytical
results.},
Doi = {10.1049/cp.2011.0098},
Key = {fds283741}
}
@article{fds283742,
Author = {Zhu, CH and Liu, QH and Shen, Y and Liu, L},
Title = {An analytical convolution method combined with the conformal
fourier transform for solving 1-D integral
equations},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {10},
Pages = {1267-1269},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {December},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2011.2174602},
Abstract = {A new solver, the analytical convolution method (ACM)
combined with the conformal Fourier transform (CFT), is
proposed for 1-D integral equations in electromagnetics. ACM
directly obtains the convolution between the Green's
function and the induced current density in a closed form.
CFT provides a highly accurate Fourier transform of the
discontinuous current density. Numerical results show that
the ACM-CFT solver is several orders of magnitude more
accurate than the traditional methods such as the
conjugate-gradient fast Fourier transform (FFT) method, and
its CPU time is significantly shorter. © 2006
IEEE.},
Doi = {10.1109/LAWP.2011.2174602},
Key = {fds283742}
}
@article{fds283740,
Author = {Simsek, E and Liu, J and Liu, QH},
Title = {A spectral integral method for the analysis of nano
wires},
Journal = {2011 30th Ursi General Assembly and Scientific Symposium,
Ursigass 2011},
Publisher = {IEEE},
Year = {2011},
Month = {November},
url = {http://dx.doi.org/10.1109/URSIGASS.2011.6050394},
Abstract = {This work presents a spectrally accurate method for
electromagnetic scattering from objects with complex
permittivity embedded in a layered medium. Two-dimensional
(2D) layered medium Green's functions are computed
adaptively by using Gaussian quadratures. The singular terms
in the Green's functions and the non-smooth terms in their
derivatives are handled appropriately to achieve exponential
convergence. Numerical results, compared with the ones
obtained by using other methods, demonstrate the spectral
accuracy and high efficiency of the proposed method. © 2011
IEEE.},
Doi = {10.1109/URSIGASS.2011.6050394},
Key = {fds283740}
}
@article{fds283739,
Author = {Tobon, L and Chen, J and Liu, QH},
Title = {Multilayer microwave filter design using a locally implicit
discontinuous Galerkin finite-element time-domain (DG-FETD)
method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2972-2975},
Publisher = {IEEE},
Year = {2011},
Month = {November},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2011.5997153},
Abstract = {A design of a multilayer microwave filter with electrical
small parts is presented in this paper using an efficient
implementation of locally implicit discontinuous Galerkin
finite element time domain method (LIDG-FETD). Discontinuous
Galerkin's method allows the division of the model in
several domains, with a reduction of the total number of
unknowns by using unstructured meshes. Furthermore, in order
to get an unconditionally stable (arbitrary t) and efficient
time stepping algorithm, the implicit Crank-Nicolson method
with block successive over relaxation (CN-BSOR) was
implemented. Accurate and fast results were obtained respect
to commercial software. © 2011 IEEE.},
Doi = {10.1109/APS.2011.5997153},
Key = {fds283739}
}
@article{fds283737,
Author = {Wang, L and Yuan, MQ and Liu, QH},
Title = {A dual-band printed electrically small antenna covered by
two capacitive split-ring resonators},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {10},
Pages = {824-826},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {September},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2011.2164890},
Abstract = {In this letter, we present a dual-band electrically small
antenna (ESA) operating at 934 MHz and 1.55 GHz. The
miniaturized radiation structure consists of a small ring
and two concentric split-ring resonators on an FR-4
substrate. The resonant response of the proposed radiation
structure is characterized by the coupling among two
split-ring resonators and the small ring. A weak electric
field interaction between two split-ring resonators is
observed. This interaction provides an additional
capacitance to further reduce the total dimension of the
resonant electrical length. The calculated return loss of
the proposed structure agrees well with the measured data.
Measured radiation patterns are presented. The planar
structure is promising for compact wireless devices and may
find applications in wireless electrocardiograph sensors,
multiband portable MIMO wireless systems, and RF
energy-harvesting systems. © 2011 IEEE.},
Doi = {10.1109/LAWP.2011.2164890},
Key = {fds283737}
}
@article{fds283751,
Author = {Chen, J and Tobon, LE and Chai, M and Mix, JA and Liu,
QH},
Title = {Efficient implicit-explicit time stepping scheme with domain
decomposition for multiscale modeling of layered
structures},
Journal = {Ieee Transactions on Components, Packaging and Manufacturing
Technology},
Volume = {1},
Number = {9},
Pages = {1438-1446},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {September},
ISSN = {2156-3950},
url = {http://dx.doi.org/10.1109/TCPMT.2011.2162726},
Abstract = {An efficient time-domain technique is proposed for
multiscale electromagnetic simulations of layered
structures. Each layer of a layered structure is
independently discretized by finite elements, and the
discontinuous Galerkin method is employed to stitch all
discretized subdomains together. The hybrid
implicit-explicit Runge-Kutta scheme combined with
subdomain-based Gauss-Seidel iteration is employed for time
stepping. The block Thomas algorithm is utilized to
accelerate time stepping for block tri-diagonal systems,
which are frequently encountered in discretized layered
structures. Numerical examples demonstrate that the proposed
method is efficient in simulating multiscale layered
structures. © 2011 IEEE.},
Doi = {10.1109/TCPMT.2011.2162726},
Key = {fds283751}
}
@article{fds283748,
Author = {Yang, K and Zhao, Z and Nie, Z and Ouyang, J and Liu,
QH},
Title = {Synthesis of conformal phased arrays with embedded element
pattern decomposition},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {59},
Number = {8},
Pages = {2882-2888},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {August},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2011.2158954},
Abstract = {A novel embedded element pattern decomposition method is
proposed to synthesize conformal phased antenna arrays. This
method decomposes the embedded element patterns as a product
of a characteristic matrix and a Vandermonde structured
matrix. This Vandermonde matrix is composed of modes in the
modal space at the sampling angles. Because the fast Fourier
transform (FFT) algorithm can be used in the Vandermonde
structure, the computational cost can be reduced
tremendously. In addition to its computational efficiency,
the proposed method is also applicable to the synthesis of a
pattern with any mainlobe direction and optimized
polarization. A modified particle swarm optimization (PSO)
method is applied to optimize the weights of the modes. This
method is demonstrated through a simulation of a 9-element
conformal array. The results show the advantages of the new
method in achieving a low peak side lobe, accurate mainlobe
scanning, and low cross-polarization. © 2011
IEEE.},
Doi = {10.1109/TAP.2011.2158954},
Key = {fds283748}
}
@article{fds283735,
Author = {He, Y and Liang, CH and Liu, QH},
Title = {Novel array EBG structures for ultrawideband simultaneous
switching noise suppression},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {10},
Pages = {588-591},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {July},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2011.2158631},
Abstract = {Based on the concept of localization, a novel array design
etching electromagnetic band-gap (EBG) structures on both
the power plane and ground plane in the region of noise
source and noise-sensitive devices is first proposed to
mitigate simultaneous switching noise (SSN). Then, a
super-array design is proposed for better suppression. It
has shown good performance in eliminating noise. The -55-dB
suppression bandwidth can be broadened from 244 MHz to 20
GHz. © 2011 IEEE.},
Doi = {10.1109/LAWP.2011.2158631},
Key = {fds283735}
}
@article{fds283732,
Author = {Liu, YH and Liu, QH and Nie, ZP and Zhao, ZQ},
Title = {Discontinuous fast fourier transform with triangle mesh for
two-dimensional discontinuous functions},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {25},
Number = {7},
Pages = {1045-1057},
Publisher = {Informa UK Limited},
Year = {2011},
Month = {April},
ISSN = {0920-5071},
url = {http://dx.doi.org/10.1163/156939311795253975},
Abstract = {In computational electromagnetics and other areas of
computational science, Fourier transforms of discontinuous
functions are frequently encountered. This paper extends the
discontinuous fast Fourier transform (DFFT) algorithm which
was presented previously by Fan and Liu to deal with the two
dimensional (2-D) function with a discontinuous boundary of
arbitrary shape. First, the proposed algorithm discretizes
the support domain of the function by triangle mesh, which
reduces the stair-casing error of an orthogonal grid
required by FFT. Second, the algorithm adopts the basic idea
of double interpolation used by the original 1-D DFFT
algorithm in the literature, but with a significant
modification that the nonuniform fast Fourier transform
(NUFFT) with the least square error (LSE) interpolation
other than a Lagrange interpolation is used to process
nonuniformly spaced samples of the exponentials. The
proposed 2-D DFFT algorithms obtain much higher accuracy
than the conventional 2-D FFT for the discontinuous
functions while maintaining similar computational complexity
as that of the 2-D FFT. © 2011 VSP.},
Doi = {10.1163/156939311795253975},
Key = {fds283732}
}
@article{fds283746,
Author = {Zhang, J and Huang, Y and Song, LP and Liu, QH},
Title = {Fast and accurate 3-D ray tracing using bilinear traveltime
interpolation and the wave front group marching},
Journal = {Geophysical Journal International},
Volume = {184},
Number = {3},
Pages = {1327-1340},
Publisher = {Oxford University Press (OUP)},
Year = {2011},
Month = {March},
ISSN = {0956-540X},
url = {http://dx.doi.org/10.1111/j.1365-246X.2010.04909.x},
Abstract = {We propose a new ray tracing technique in a 3-D
heterogeneous isotropic media based on bilinear traveltime
interpolation and the wave front group marching. In this
technique, the media is discretized into a series of
rectangular cells. There are two steps to be carried out:
one is a forward step where wave front expansion is evolved
from sources to whole computational domain and the
subsequent one is a backward step where ray paths are
calculated for any source-receiver configuration as desired.
In the forward step, we derive a closed-form expression to
calculate traveltime at an arbitrary point in a cell using a
bilinear interpolation of the known traveltimes on the
cell's surface. Then the group marching method (GMM), a fast
wave front advancing method, is applied to expand the wave
front from the source to all girds. In the backward step,
ray paths starting from receivers are traced by finding the
intersection points of potential ray propagation vectors
with the surfaces of relevant cells. In this step, the same
TI scheme is used to compute the candidate intersection
points on all surfaces of each relevant cell. In this
process, the point with the minimum traveltime is selected
as a ray point from which the similar step is continued
until sources. A number of numerical experiments demonstrate
that our 3-D ray tracing technique is able to achieve very
accurate computation of traveltimes and ray paths and
meanwhile take much less computer time in comparison with
the existing popular ones like the finite-difference-based
GMM method, which is combined with the maximum gradient ray
tracing, and the shortest path method. © 2011 The Authors
Geophysical Journal International © 2011
RAS.},
Doi = {10.1111/j.1365-246X.2010.04909.x},
Key = {fds283746}
}
@article{fds283743,
Author = {Huang, Y and Zhang, J and Liu, QH},
Title = {Three-dimensional GPR ray tracing based on wavefront
expansion with irregular cells},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {49},
Number = {2},
Pages = {679-687},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {February},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2010.2061856},
Abstract = {A new ray-tracing method in 3-D heterogeneous isotropic
media is proposed based on the bilinear travel-time
interpolation and wavefront group marching method (GMM). In
this method, an irregular cell discretization scheme is used
to accurately describe arbitrarily undulant interfaces in a
model. The ray tracing is carried out by forward-backward
processing. In the forward step, the travel time in an
irregular cell is expressed in terms of the bilinear
interpolation of the known travel times on the cell's
surfaces. Then, the wavefront is evolved from the source to
the whole computational domain by using the newly developed
travel-time solver and the fast wavefront expansion GMM. In
the backward step, each ray path is traced from the receiver
by finding the intersection points of potential ray
propagation vectors with the surfaces of the relevant cells.
The same travel-time solver is used to compute the candidate
intersection points on all surfaces of each relevant cell,
and the point with the minimum travel time is selected as a
ray point from which the similar step is continued until the
sources are found. Several numerical experiments are
presented to demonstrate that the new algorithm is accurate,
efficient, and robust. © 2006 IEEE.},
Doi = {10.1109/TGRS.2010.2061856},
Key = {fds283743}
}
@article{fds283731,
Author = {Liu, Y and Nie, Z and Zhao, Z and Liu, QH},
Title = {Generalization of iterative Fourier interpolation algorithms
for single frequency estimation},
Journal = {Digital Signal Processing},
Volume = {21},
Number = {1},
Pages = {141-149},
Publisher = {Elsevier BV},
Year = {2011},
Month = {January},
ISSN = {1051-2004},
url = {http://dx.doi.org/10.1016/j.dsp.2010.06.012},
Abstract = {The problem of estimating the frequency of a complex single
tone is considered. We generalize two iterative Fourier
interpolation algorithms in the literature by introducing an
additional parameter to allow for selection of the Fourier
interpolation coefficients relative to the true frequency.
The generalized algorithms can use more information from FFT
results and consequently achieve significant improvement
over the original algorithms in either accuracy or
efficiency. Simulation results show advantages of the
proposed algorithms. © 2010 Elsevier Inc. All rights
reserved.},
Doi = {10.1016/j.dsp.2010.06.012},
Key = {fds283731}
}
@article{fds283733,
Author = {Yuan, M and Liu, QH},
Title = {The diagonal tensor approximation (DTA) for objects in a
non-canonical nhomoge-neous background},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {112},
Pages = {1-21},
Publisher = {EMW Publishing},
Year = {2011},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER10110804},
Abstract = {A non-canonical inhomogeneous background medium is one whose
Green's function cannot be obtained by an analytical method.
Electromagnetic scattering from objects embedded in a
non-canonical inhomogeneous background medium is very
challenging because of the computational complexity with the
calculation of its Green's function and the multiple
scattering between objects and the background. This work
applies the Diagonal Tensor Approximation (DTA) to calculate
the scattering from arbitrary objects in a non- canonical
inhomogeneous background. Previously, the DTA has only been
applied to a canonical background such as a homogeneous or
layered background media. This approach employs a numerical
method to obtain all Green's functions required in the
calculation; an accurate DTA is used to calculate the
scattering properties. In order to reduce the large number
of simulations, we employ the symmetry and reciprocity in
the Green's function calculation. Furthermore, considering
that most realistic imaging measurements are made through a
voltage probe usually represented by a wave port, we develop
a method to convert the scattered field on the probe (the
antenna) to the measured wave port voltage. Numerical
results show that this method can obtain accurate scattering
characteristics from arbitrary objects in a non-canonical
inhomogeneous background medium in a microwave imaging
system.},
Doi = {10.2528/PIER10110804},
Key = {fds283733}
}
@article{fds283734,
Author = {Chen, J and Zhu, B and Zhong, W and Liu, QH},
Title = {A semianalytical spectral element method for the analysis of
3-D layered structures},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {59},
Number = {1},
Pages = {1-8},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
Month = {January},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2010.2090408},
Abstract = {A semianalytical spectral element method (SEM) is proposed
for electromagnetic simulations of 3-D layered structures.
2-D spectral elements are employed to discretize the cross
section of a layered structure, and the Legendre
transformation is then used to cast the semidiscretized
problem from the Lagrangian system into the Hamiltonian
system. A Riccati equation-based high precision integration
method is utilized to perform integration along the
longitudinal direction, which is the undiscretized
direction, to generate the stiffness matrix of the whole
layered structure. The final system of equations by the
semianalytical SEM will take the form of a set of linear
equations with a block tri-diagonal matrix, which can be
solved efficiently by the block Thomas algorithm. Numerical
examples demonstrate the high efficiency and accuracy of the
proposed method. © 2010 IEEE.},
Doi = {10.1109/TMTT.2010.2090408},
Key = {fds283734}
}
@article{fds283736,
Author = {Zhu, X and Zhao, Z and Yang, W and Zhang, Y and Nie, Z and Liu,
QH},
Title = {Iterative time-reversal mirror method for imaging the buried
object beneath rough ground surface},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {117},
Pages = {19-33},
Publisher = {EMW Publishing},
Year = {2011},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER11041304},
Abstract = {An iterative Time-Reversal Mirror (TRM) method is proposed
to Detect and Image the buried target beneath ground
surface. Unlike the conventional TRM methods which treat the
information of the ground as clutters and directly delete
them, the iterative TRM imaging method proposed in this
paper utilizes the information of rough ground surface as a
useful knowledge. The new approach is consisted of two TRM
procedures. In the -rst TRM procedure, it aims to image the
rough surface where the propagation environment for
electromagnetic wave is free space. The second TRM procedure
aims to image the buried target. In this step, the
information of the rough surface estimated by the -rst TRM
procedure will be treated as newly updated propagation
environment. Then conventional TRM is applied to image the
buried target. By applying this iterative TRM method, the
information of the rough ground can be well considered in
the whole TRM procedure. Numerical simulations prove that
this method performs signi-cantly better image contrast
comparing with the results obtained by using conventional
TRM. 4-5 dB improvement on the imaging SNR has been
achieved. Furthermore, the target can be located more
accurately.},
Doi = {10.2528/PIER11041304},
Key = {fds283736}
}
@article{fds283738,
Author = {Zhu, CH and Liu, QH and Liu, YH and Shen, Y and Liu,
LJ},
Title = {An accurate conformal Fourier transform method for 2D
discontinuous functions},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {120},
Pages = {165-179},
Publisher = {EMW Publishing},
Year = {2011},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER11072306},
Abstract = {Fourier transform of discontinuous functions are often
encountered in computational electromagnetics. A highly
accurate, fast conformal Fourier transform (CFT) algorithm
is proposed to evaluate the finite Fourier transform of 2D
discontinuous functions. A curved triangular mesh combined
with curvilinear coordinate transformation is adopted to
flexibly model an arbitrary shape of the discontinuity
boundary. This enables us to take full advantages of high
order interpolation and Gaussian quadrature methods to
achieve highly accurate Fourier integration results with a
low sampling density and small computation time. The
complexity of the proposed algorithm is similar to the
traditional 2D fast Fourier transform algorithm, but with
orders of magnitude higher accuracy. Numerical examples
illustrate the excellent performance of the proposed CFT
method.},
Doi = {10.2528/PIER11072306},
Key = {fds283738}
}
@article{fds283744,
Author = {Zhu, B and Chen, J and Zhong, W and Liu, QH},
Title = {A hybrid FETD-FDTD method with nonconforming
meshes},
Journal = {Communications in Computational Physics},
Volume = {9},
Number = {3},
Pages = {828-842},
Publisher = {Global Science Press},
Year = {2011},
Month = {January},
ISSN = {1815-2406},
url = {http://dx.doi.org/10.4208/cicp.230909.140410s},
Abstract = {A quasi non-overlapping hybrid scheme that combines the
finite-difference time-domain (FDTD)method and the
finite-element time-domain (FETD)methodwith nonconforming
meshes is developed for time-domain solutions of Maxwell's
equations. The FETD method uses mixed-order basis functions
for electric and magnetic fields, while the FDTD method uses
the traditional Yee's grid; the two methods are joined by a
buffer zonewith the FETDmethod and the discontinuous
Galerkinmethod is used for the domain decomposition in the
FETD subdomains. The main features of this technique is that
it allows non-conforming meshes and an arbitrary numbers of
FETD and FDTD subdomains. The hybrid method is completely
stable for the time steps up to the stability limit for the
FDTD method and FETD method. Numerical results demonstrate
the validity of this technique. © 2011 Global-Science
Press.},
Doi = {10.4208/cicp.230909.140410s},
Key = {fds283744}
}
@article{fds283745,
Author = {Luo, M and Liu, QH},
Title = {Extraordinary transmission of a thick film with a periodic
structure consisting of strongly dispersive
materials},
Journal = {Journal of the Optical Society of America
B},
Volume = {28},
Number = {4},
Pages = {629-636},
Publisher = {The Optical Society},
Year = {2011},
Month = {January},
ISSN = {0740-3224},
url = {http://dx.doi.org/10.1364/JOSAB.28.000629},
Abstract = {Enhanced reflections and transmissions by slabs of periodic
structures with strongly dispersive materials have recently
received significant attention because of their unusual
physical phenomena and potential engineering applications.
To simulate such phenomena for design prototyping with high
efficiency, a spectral element method is developed to
calculate the electromagnetic fields in a slab of periodic
three-dimensional photonic crystal consisting of dispersive
or nondispersive materials. The method of moments with the
spectral-domain periodic Green's function is used to
truncate the computational domain above and below the
photonic crystal slabs. The accuracy of the method is
verified. The method is used to calculate the scattering
properties of an array of air holes in a dispersive metallic
film in optical frequencies. The surface plasmon polariton
and local surface plasmon modes are identified, with
excellent correlation with experimental results. © 2011
Optical Society of America.},
Doi = {10.1364/JOSAB.28.000629},
Key = {fds283745}
}
@article{fds283747,
Author = {Tobón, L and Chen, J and Liu, QH},
Title = {Spurious solutions in mixed finite element method for
Maxwell's equations: Dispersion analysis and new basis
functions},
Journal = {Journal of Computational Physics},
Volume = {230},
Number = {19},
Pages = {7300-7310},
Publisher = {Elsevier BV},
Year = {2011},
Month = {January},
ISSN = {0021-9991},
url = {http://dx.doi.org/10.1016/j.jcp.2011.05.035},
Abstract = {The finite element method is a well known computational
technique used to obtain numerical solutions to
boundary-value problems including Maxwell's equations. This
paper first presents a brief description of the mathematical
structure, based on the De Rham diagram, to discretize
Maxwell's equations. Then it uses a numerical dispersion
analysis of the mixed finite element method with both
electric and magnetic fields as unknowns to evaluate the
presence of spurious solutions for different basis
functions. These unwanted spurious solutions appear when the
same order of element is used for electric and magnetic
fields, while the system is free of spurious modes when
different orders of elements are employed for electric and
magnetic fields. In this work, finite elements in both
frequency and time domain are studied, and the effects of
these spurious solutions in both domains are analyzed in
one- and three-dimensional cases. © 2011 Elsevier
Inc.},
Doi = {10.1016/j.jcp.2011.05.035},
Key = {fds283747}
}
@article{fds283749,
Author = {Luo, M and Liu, QH},
Title = {Enhancement of second-harmonic generation in an air-bridge
photonic crystal slab: Simulation by spectral element
method},
Journal = {Journal of the Optical Society of America
B},
Volume = {28},
Number = {12},
Pages = {2879-2887},
Publisher = {The Optical Society},
Year = {2011},
Month = {January},
ISSN = {0740-3224},
url = {http://dx.doi.org/10.1364/JOSAB.28.002879},
Abstract = {The enhancement of second-harmonic generation (SHG) across a
2D photonic crystal (PC) slab consisting of GaP is
investigated in this study with the three-dimensional
spectral element method (SEM). The in-plane band structure
is calculated, and it is compared with the peaks of the SHG
to reveal the mechanisms behind the enhancement. The
numerical result from the SEM shows that, under normal
incidence, the scattered power of the SHG is enhanced for
the eigenstates with large decay rates, while the stored
energy of the SHG is enhanced for the eigenstates with a
zero decay rate. The SHG is enhanced under two conditions:
(i) phase matching between the fundamental and
second-harmonic (SH) fields and (ii) symmetry matching
between the field pattern of the resonant eigenstate and the
generated SH polarization field. Compared with a homogeneous
dielectric slab, the air-bridge PC slab can enhance the SHG
by 4 orders of magnitude. © 2011 Optical Society of
America.},
Doi = {10.1364/JOSAB.28.002879},
Key = {fds283749}
}
@article{fds323119,
Author = {Tobon, L and Chen, J and Liu, QH},
Title = {Multilayer Microwave Filter Design using a Locally Implicit
Discontinuous Galerkin Finite-Element Time-Domain (DG-FETD)
Method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2965-2968},
Publisher = {IEEE},
Year = {2011},
Month = {January},
Key = {fds323119}
}
@article{fds283781,
Author = {Wang, L and Yuan, M and Xiao, T and Joines, WT and Liu,
QH},
Title = {Broadband electromagnetic radiation modulated by dual
memristors},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {10},
Pages = {623-626},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2011},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2011.2160038},
Abstract = {Using dual high-speed memristors, we report on an efficient
broadband electromagnetic radiation from a narrowband
microstrip patch antenna. The directly modulated microstrip
patch antenna system with dual memristors is calculated by
using an integrated full-wave finite-difference time-domain
method with an embedded SPICE3 solver. Nonlinear transient
electromagnetic response is analyzed. The radiation
frequency spectrum demonstrates the broadband radiation
performance from the narrowband antenna system. © 2011
IEEE.},
Doi = {10.1109/LAWP.2011.2160038},
Key = {fds283781}
}
@article{fds283715,
Author = {Simsek, E and Liu, QH},
Title = {Design of optical devices using frequency domain
solvers},
Journal = {Symposium Digest 20th Ursi International Symposium on
Electromagnetic Theory, Emts 2010},
Pages = {536-539},
Publisher = {IEEE},
Year = {2010},
Month = {December},
url = {http://dx.doi.org/10.1109/URSI-EMTS.2010.5637183},
Abstract = {This work deals with efficient frequency domain solvers
specifically developed to design optical and plasmonic
devices. Homogeneous and inhomogeneous objects embedded in
multilayered media are analyzed using Method of Moment (MoM)
and hybrid MoM-Finite Element Method (FEM), respectively.
The capability of working with materials of complex
permittivity makes these algorithms valid and useful for
both microwave and optical regimes. Based on the good match
between numerical results obtained with these algorithms and
the ones found in the literature, we propose an optical
antenna optimum for a semiconductor laser diode operating at
a wavelength of 830 nm and an infrared sensor compatible
with present silicon technology based optical devices. ©
2010 IEEE.},
Doi = {10.1109/URSI-EMTS.2010.5637183},
Key = {fds283715}
}
@article{fds283720,
Author = {He, Y and Liang, CH and Li, L and Liu, QH},
Title = {Novel wavy EBG structures for ultra-wideband ground bounce
noise suppression},
Journal = {2010 9th International Symposium on Antennas Propagation and
Em Theory, Isape 2010},
Pages = {1132-1135},
Publisher = {IEEE},
Year = {2010},
Month = {December},
url = {http://dx.doi.org/10.1109/ISAPE.2010.5696677},
Abstract = {Two novel wavy electromagnetic bandgap (EBG) structures have
been proposed and applied to power/ground plane pairs for
ultra-wideband ground bounce noise (GBN) suppression. The
proposed two designs have shown good performance. The -40 dB
suppression bandwidth of the first design is from 344 MHz to
20 GHz. For the second design, the - 49 dB suppression
bandwidth is from 304 MHz to 20 GHz. Both results of
simulation and measurement are presented to verify the
performance. ©2010 IEEE.},
Doi = {10.1109/ISAPE.2010.5696677},
Key = {fds283720}
}
@article{fds283714,
Author = {Rui, X and Hu, J and Liu, QH},
Title = {Scattering from a composite body of revolution with fast
inhomogeneous plane wave algorithm},
Journal = {2010 Ieee International Symposium on Antennas and
Propagation and Cnc Usnc/Ursi Radio Science Meeting Leading
the Wave, Ap S/Ursi 2010},
Publisher = {IEEE},
Year = {2010},
Month = {November},
url = {http://dx.doi.org/10.1109/APS.2010.5561224},
Abstract = {The electromagnetic radiation and scattering from a body of
revolution (BOR) of arbitrary shape have been widely
discussed during several decades. The objects can contain
perfect electric conductor (PEC), homogeneous dielectric
bodies, coated conducting bodies and combined dielectric and
conducting bodies [1][2]. The traditional method used to
solve BOR with integral equations is the Method of Moments
(MoM). And the computational time consumed in solving the
integral equation of the BOR problem depends on the
evaluation of modal Green's function (MGF), which is a time
consuming process. Some research has been done to reduce
this computational complexity. For example, Abdelmageed used
spherical Bessel function to expansion to evaluate the MGF
[3]. In this work, we extend the fast inhomogeneous plane
wave algorithm (FIPWA) [4][5] to accelerate the computation
of the MoM for composite homogeneous dielectric and
conducting bodies of revolution. PMCHW [6]
(Poggio-Miller-Chang-Harrington-Wu) equations and electric
field integral equation are used for solving the homogeneous
dielectric and conducting objects, respectively. Both the
memory requirement and CPU time are reduced for large-scale
BOR problems. Numerical results are given to demonstrate the
validity and efficiency of the FIPWA. © 2010
IEEE.},
Doi = {10.1109/APS.2010.5561224},
Key = {fds283714}
}
@article{fds283716,
Author = {Chen, J and Liu, QH},
Title = {A hybrid spectral-element/finite-element method with the
implicit-explicit Runge-Kutta Time Stepping Scheme for
Multiscale Computation},
Journal = {2010 Ieee International Symposium on Antennas and
Propagation and Cnc Usnc/Ursi Radio Science Meeting Leading
the Wave, Ap S/Ursi 2010},
Publisher = {IEEE},
Year = {2010},
Month = {November},
url = {http://dx.doi.org/10.1109/APS.2010.5561916},
Abstract = {Realistic system level electromagnetic problems such as
electronic packaging are often multiscale, where
electrically fine structures and electrically coarse
structures coexist. Simulating the transient multiscale
problems can be very challenging for conventional numerical
techniques: the dense mesh/grid for fine structures will
lead to a large number of wasted unknowns in the coarse
domains. Besides, small cells for fine structures make the
size of time steps extremely small, thus lead to an
unaffordable number of steps in time integration. Here we
propose a hybrid spectral-element/finite- element method
(SEM/FEM) combined with the implicit-explicit Runge-Kutta
(IMEX-RK) scheme for multiscale electromagnetic computation.
This method is flexible in spatial discretization and
efficient in time stepping. The basic idea and numerical
results are presented in following sections. © 2010
IEEE.},
Doi = {10.1109/APS.2010.5561916},
Key = {fds283716}
}
@article{fds283730,
Author = {Wang, J and Yin, WY and Liu, PG and Liu, QH},
Title = {High-order interface treatment techniques for modeling
curved dielectric objects},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {58},
Number = {9},
Pages = {2946-2953},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
Month = {September},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2010.2052562},
Abstract = {Three modified conformal techniques combined with high-order
finite-difference time-domain method (FDTD (2, 4)) are
proposed to investigate the interaction of electromagnetic
waves with three-dimensional (3-D) curved dielectric
surfaces. These proposed conformal techniques utilize an
effective average dielectric constant to modify the update
equations in the FDTD (2, 4) scheme, which is derived by
area, linear, and volume averages of different dielectric
regions in twenty seven spatial discrete cells at most,
respectively. Some numerical results are presented to show
the accuracies of linear and area average techniques. Good
agreements are obtained with those of the method of moments
and other analytical ones, even with coarse meshes adopted
for handling electrically large or complex geometries
effectively. Further, using our proposed techniques, the RCS
of some typical 3-D objects are predicted and studied in
detail. © 2006 IEEE.},
Doi = {10.1109/TAP.2010.2052562},
Key = {fds283730}
}
@article{fds283726,
Author = {Kong, FZ and Yin, WY and Mao, JF and Liu, QH},
Title = {Electro-thermo-mechanical characterizations of various wire
bonding interconnects illuminated by an electromagnetic
pulse},
Journal = {Ieee Transactions on Advanced Packaging},
Volume = {33},
Number = {3},
Pages = {729-737},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
Month = {August},
ISSN = {1521-3323},
url = {http://dx.doi.org/10.1109/TADVP.2010.2048902},
Abstract = {A comprehensive electro-thermo-mechanical transient
investigation is carried out to characterize time-dependent
thermal and mechanical responses of metal wire bonding
interconnects, as they suffer from the impact of an
electromagnetic pulse (EMP) with different current or
voltage waveforms. In our mathematical implementation, a
hybrid time-domain finite element method is applied to
simulate mutual interactions among electrical, thermal, and
mechanical fields, with all nonlinearities of
temperature-dependent electrical conductivities, thermal
conductivities, thermal expansion coefficients, and even the
Young's modulus of materials being treated appropriately.
The developed algorithm is partially validated by computing
transient temperature and thermal stress of other
interconnects with good agreement with reference results.
Parametric studies are performed to show the effects of EMP
waveform parameters, geometrical and physical parameters of
various wire bonding interconnects on their transient
thermal and mechanical responses, thus providing basic
information for their electromagnetic protection so as to
suppress the impact of an intentional EMP. © 2006
IEEE.},
Doi = {10.1109/TADVP.2010.2048902},
Key = {fds283726}
}
@article{fds283727,
Author = {Rui, X and Hu, J and Liu, QH},
Title = {Fast inhomogeneous plane wave algorithm for scattering from
PEC body of revolution},
Journal = {Microwave and Optical Technology Letters},
Volume = {52},
Number = {8},
Pages = {1915-1922},
Publisher = {WILEY},
Year = {2010},
Month = {August},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.25319},
Abstract = {To solve large-scale electromagnetic scattering problems for
bodies of revolution, a fast inhomogeneous plane wave
algorithm (FIPWA) is developed. By using the Weyl identity
and designing a proper integral path, the aggregation and
disaggregation factors can be computed efficiently in FIPWA.
Both the memory and CPU time requirements are significantly
reduced for large scale BOR problems over the method of
moments. Numerical results are given to demonstrate the
validity and the efficiency of the FIPWA method to perfect
conductors, but the method can be extended to dielectric
BORs. © 2010 Wiley Periodicals, Inc.},
Doi = {10.1002/mop.25319},
Key = {fds283727}
}
@article{fds283728,
Author = {Luo, M and Liu, QH},
Title = {Three-dimensional dispersive metallic photonic crystals with
a bandgap and a high cutoff frequency.},
Journal = {Journal of the Optical Society of America
A},
Volume = {27},
Number = {8},
Pages = {1878-1884},
Year = {2010},
Month = {August},
url = {http://www.ncbi.nlm.nih.gov/pubmed/20686594},
Abstract = {The goal of this work is to analyze three-dimensional
dispersive metallic photonic crystals (PCs) and to find a
structure that can provide a bandgap and a high cutoff
frequency. The determination of the band structure of a PC
with dispersive materials is an expensive nonlinear
eigenvalue problem; in this work we propose a
rational-polynomial method to convert such a nonlinear
eigenvalue problem into a linear eigenvalue problem. The
spectral element method is extended to rapidly calculate the
band structure of three-dimensional PCs consisting of
realistic dispersive materials modeled by Drude and
Drude-Lorentz models. Exponential convergence is observed in
the numerical experiments. Numerical results show that, at
the low frequency limit, metallic materials are similar to a
perfect electric conductor, where the simulation results
tend to be the same as perfect electric conductor PCs. Band
structures of the scaffold structure and semi-woodpile
structure metallic PCs are investigated. It is found that
band structures of semi-woodpile PCs have a very high cutoff
frequency as well as a bandgap between the lowest two bands
and the higher bands.},
Doi = {10.1364/josaa.27.001878},
Key = {fds283728}
}
@article{fds283710,
Author = {Kim, CE and Jeon, MH and Shin, PS and Liu, QH},
Title = {The analysis of flow characteristics of molten metal
coupling electromagnetic with Navier-Stokes
equation},
Journal = {Digests of the 2010 14th Biennial Ieee Conference on
Electromagnetic Field Computation, Cefc 2010},
Publisher = {IEEE},
Year = {2010},
Month = {July},
url = {http://dx.doi.org/10.1109/CEFC.2010.5481689},
Abstract = {This paper presents the flow characteristics in the fluid
circulation system using an electromagnetic pump on a molten
metal. The flow characteristics of molten metal are analyzed
by coupling electromagnetic with Navier-Stokes equations.
The analysis results will be compared with the result of the
experiment. © 2010 IEEE.},
Doi = {10.1109/CEFC.2010.5481689},
Key = {fds283710}
}
@article{fds283711,
Author = {Chen, J and Liu, QH and Chai, M and Mix, JA},
Title = {Analysis of spurious modes in mixed finite element method
for Maxwell's equation with E and H as variables},
Journal = {Digests of the 2010 14th Biennial Ieee Conference on
Electromagnetic Field Computation, Cefc 2010},
Publisher = {IEEE},
Year = {2010},
Month = {July},
url = {http://dx.doi.org/10.1109/CEFC.2010.5481503},
Abstract = {In this study the formulations of mixed finite element (FEM)
method for Maxwell's equations with E and H as variables are
given, and the appearance of spurious modes of this mixed
FEM are discussed. Numerical experiments demonstrate that
the spurious modes can be eliminated by choosing the
interpolation degrees for E different from that for H. This
non-spurious mixed FEM scheme can be utilized in both time
domain and frequency domain, and it is very suitable for the
future implementation of the discontinuous Galekin finite
element method (DG-FEM). © 2010 IEEE.},
Doi = {10.1109/CEFC.2010.5481503},
Key = {fds283711}
}
@article{fds283712,
Author = {Huang, Y and Chen, J and Zhang, J and Liu, QH},
Title = {A parallel high precision integration scheme with spectral
element method for transient electromagnetic
computation},
Journal = {Digests of the 2010 14th Biennial Ieee Conference on
Electromagnetic Field Computation, Cefc 2010},
Publisher = {IEEE},
Year = {2010},
Month = {July},
url = {http://dx.doi.org/10.1109/CEFC.2010.5481611},
Abstract = {A parallel high precision integration (HPI) scheme combined
with the spectral element method (SEM) is presented to solve
the time-dependent Maxwell's equations. The vector spectral
elements are employed for spatial discretization, and a
parallel HPI scheme based on matrix exponential and time
domain segmentation is proposed for solving the
semi-discretized system by SEM. The parallel HPI is
unconditionally stable and very suitable for long time
simulation. Numerical examples demonstrate that the proposed
method can achieve accuracy several orders higher than that
of conventional time stepping methods such as the
Runge-Kutta schemes. © 2010 IEEE.},
Doi = {10.1109/CEFC.2010.5481611},
Key = {fds283712}
}
@article{fds283713,
Author = {Huang, Y and Liu, QH and Zhang, J},
Title = {Fast three-dimensional GPR forward and inverse scattering
based on wideband diagonal tensor approximation},
Journal = {Digests of the 2010 14th Biennial Ieee Conference on
Electromagnetic Field Computation, Cefc 2010},
Publisher = {IEEE},
Year = {2010},
Month = {July},
url = {http://dx.doi.org/10.1109/CEFC.2010.5481592},
Abstract = {A fast three-dimensional (3D) ground penetrating radar (GPR)
forward and inverse scattering method is presented based on
the diagonal tensor approximation (DTA). For the forward
scattering problem, the first iteration about the
frequency-dependent scattering coefficients in the DTA is
used. By further evaluating the scattering tensor at the GPR
center frequency to remove its frequency dependence, the DTA
is simplified while maintaining higher accuracy than the
classical Born approximation method. For the inverse
scattering problem, the DTA-based algorithm is derived for
the plane-wave GPR, and can be implemented efficiently by
the NUFFT combined with the stabilized bi-conjugate gradient
FFT (BiCGS-FFT) method. The proposed inversion algorithm is
much cheaper than the existing DTA-based methods, and has a
higher accuracy and a wider range of applicability than the
fast method based on the Born approximation. © 2010
IEEE.},
Doi = {10.1109/CEFC.2010.5481592},
Key = {fds283713}
}
@article{fds283709,
Author = {He, Y and Li, L and Zhai, H and Dang, X and Liang, CH and Liu,
QH},
Title = {Sierpinski space-filling curves and their application in
high-speed circuits for ultrawideband SSN
suppression},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {9},
Pages = {568-571},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
Month = {July},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2010.2052584},
Abstract = {Sierpinski space-filling curves are introduced and employed
to construct the unit-cell topologies of electromagnetic
band-gap (EBG) structures with different bridges. Three
novel designs using Sierpinski curves with first three
iterations have been proposed and applied to high-speed
circuits. From the measured data, it can be observed that
the proposed designs have shown good performance in
eliminating simultaneous switching noise (SSN). Remarkably,
the -50 dB noise suppression bandwidth of the first design
utilizing a Sierpinski curve with one iteration can be
broadened from 263 MHz to 19 GHz. Both simulation and
measured results are presented to verify the performance. ©
2006 IEEE.},
Doi = {10.1109/LAWP.2010.2052584},
Key = {fds283709}
}
@article{fds283725,
Author = {He, Y and Li, L and Liang, CH and Liu, QH},
Title = {EBG structures with fractal topologies for ultra-wideband
ground bounce noise suppression},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {24},
Number = {10},
Pages = {1365-1374},
Publisher = {Informa UK Limited},
Year = {2010},
Month = {July},
ISSN = {0920-5071},
url = {http://dx.doi.org/10.1163/156939310791958734},
Abstract = {Electromagnetic bandgap (EBG) structures consisting of
fractal high impedance topologies and effective bridges are
proposed and employed for ultra-wideband (UWB) ground bounce
noise (GBN) suppression in power and ground plane pairs.
These structures have shown good performance. For the first
design utilizing fractal high impedance topology with one
iteration and meander lines, it provides -49 dB noise
suppression from 202 MHz to 20 GHz. Both simulated and
measured results are presented to verify the performance.
Furthermore, the GBN suppression behaviors of topologies
with different iterations have been studied, and the impact
of the power plane with the first design on the signal
integrity has also been investigated. © 2010
VSP.},
Doi = {10.1163/156939310791958734},
Key = {fds283725}
}
@article{fds283707,
Author = {Rui, X and Hu, J and Liu, QH},
Title = {Higher order Finite element method for In homogeneous
axisymmetric resonators},
Journal = {Progress in Electromagnetics Research B. Pier
B},
Number = {21},
Pages = {189-201},
Year = {2010},
Month = {June},
ISSN = {1937-6472},
Abstract = {To analyze resonances in an axisymmetric inhomogeneous
cavity, a higher-order finite element method (FEM) is
developed. Mixed higher-order node-based and edge-based
elements are applied to eigenvalue analysis for the
azimuthal component and meridian components of the field,
respectively. Compared with the lower-order FEM, the
higher-order FEM can improve accuracy with the same number
of unknowns and can reduce the CPU time and memory
requirement for specified accuracy. Numerical results are
given to demonstrate the validity and efficiency of the
proposed method.},
Key = {fds283707}
}
@article{fds283706,
Author = {Zheng, W and Zhao, Z and Chen, G and Gong, W and Nie, Z and Liu,
QH},
Title = {Three-dimensional image reconstruction in microwave induced
thermo-acoustic tomography using time reversal mirror
technique},
Journal = {2010 International Conference on Biomedical Engineering and
Computer Science, Icbecs 2010},
Publisher = {IEEE},
Year = {2010},
Month = {June},
url = {http://dx.doi.org/10.1109/ICBECS.2010.5462515},
Abstract = {In recent years, microwave induced thermo-acoustic
tomography (MITAT) has been of significant interest as a
noninvasive medical imaging modality for biomedical
applications. In virtue of the combination of microwave and
acoustics imaging technique, it bears predominant advantages
in both contrast and resolution. In this paper,
three-dimensional MITAT imaging reconstruction using Time
Reversal Mirror (TRM) technique is studied computationally.
The forward and inverse phases are simulated by the
Pseudo-Spectrum Time Domain (PSTD) method. Imaging results
show that TRM technique well employs the information of wave
propagation, can provides the MITAT system with high
contrast and resolution three-dimensional image. ©2010
IEEE.},
Doi = {10.1109/ICBECS.2010.5462515},
Key = {fds283706}
}
@article{fds283724,
Author = {He, Y and Li, L and Liang, CH and Liu, QH and Wen, HB},
Title = {Leafy EBG structures for ultra-wideband SSN suppression in
power/ground plane pairs},
Journal = {Electronics Letters},
Volume = {46},
Number = {11},
Pages = {768-769},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2010},
Month = {May},
ISSN = {0013-5194},
url = {http://dx.doi.org/10.1049/el.2010.0758},
Abstract = {Two leafy electromagnetic bandgap (EBG) structures are
proposed for ultra-wideband (UWB) simultaneous switching
noise (SSN) suppression in power/ground plane pairs. The
valid-35dB suppression bandwidth of the first design is from
218MHz to 20GHz,-40dB suppression bandwidth of the second
design is from 369MHZ to 20GHz. The simulated and measured
results are compared and presented to verify good
performance. © 2010 The Institution of Engineering and
Technology.},
Doi = {10.1049/el.2010.0758},
Key = {fds283724}
}
@article{fds283722,
Author = {Luo, M and Liu, QH and Guo, J},
Title = {A spectral element method calculation of extraordinary light
transmission through periodic subwavelength
slits},
Journal = {Journal of the Optical Society of America
B},
Volume = {27},
Number = {3},
Pages = {560-566},
Publisher = {The Optical Society},
Year = {2010},
Month = {March},
ISSN = {0740-3224},
url = {http://hdl.handle.net/10161/4232 Duke open
access},
Abstract = {A spectral element method together with a surface integral
equation as the radiation boundary condition is used to
simulate the scattering properties of periodic subwavelength
slits. The surface integral equation utilizes the periodic
Green's function in the wave number space and is solved by
the method of moments, while the interior inhomogeneous
medium is modeled by the spectral element method. The
solution convergence is found to be exponential; i.e., the
error decreases exponentially with the order of basis
functions. To our knowledge, such a fast solver with
spectral accuracy is new in the scattering problem of
periodic structures. Scattering properties of a gold slit
grid within the whole wavelength-incidence angle parameter
space are investigated, with the confirmation that strong
transmission of light through subwavelength slits is
achievable. © 2010 Optical Society of America.},
Doi = {10.1364/JOSAB.27.000560},
Key = {fds283722}
}
@article{fds283723,
Author = {Chen, GP and Yu, WB and Zhao, ZQ and Nie, ZP and Liu,
QH},
Title = {The characteristics and affects of the microwave-induced
thermo-acoustic signals in time and frequency
domain},
Journal = {Tien Tzu Hsueh Pao/Acta Electronica Sinica},
Volume = {38},
Number = {3},
Pages = {689-694},
Year = {2010},
Month = {March},
ISSN = {0372-2112},
Abstract = {Microwave-induced thermo-acoustic (MITA) Tomography is a
promising technique in medical imaging area. It is a
combination of the microwave and ultrasound techniques. In
this paper, an experimental system of MITA is briefly
presented. The mechanism of MITA and some signal processing
methods are applied in analyzing the characteristics and
affects of the MITA signals. The affects, the irradiated
microwave pulse and the geometry of the tissue are studied.
Experiment results and theoretic analysis show that the
amplitude of the time domain MITA signals are proportional
to the intensity of the irradiated microwave pulse and the
cross-section of the sample. The spectrum distribution of
the MITA signals are not only affected by the spectrum of
the irradiated microwave, but also affected by the intrinsic
frequency determined by the tissue's thickness. The center
frequency of the MITA signals recorded in experiment accord
with this hypothesis.},
Key = {fds283723}
}
@article{fds283721,
Author = {Liu, Y and Liu, QH and Nie, Z},
Title = {Reducing the number of elements in the synthesis of
shaped-beam patterns by the forward-backward matrix pencil
method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {58},
Number = {2},
Pages = {604-608},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
Month = {February},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2009.2037709},
Abstract = {The matrix pencil method (MPM) has been used to reduce the
number of elements in the linear antenna array with a
pencil-beam pattern. This work extends the MPM-based
synthesis method to the synthesis of shaped-beam patterns by
using the forward-backward matrix pencil method (FBMPM). The
FBMPM-based synthesis method places a necessary restriction
on the poles which correspond to element positions, and
consequently obtains more accurate synthesis results,
particularly for the synthesis of asymmetric patterns.
Numerical examples show the effectiveness and advantages of
the proposed method in the reduction of the number of
elements for shaped-beam patterns. © 2006
IEEE.},
Doi = {10.1109/TAP.2009.2037709},
Key = {fds283721}
}
@article{fds283702,
Author = {Ren, Z and Yin, WY and Shi, YB and Liu, QH},
Title = {Thermal accumulation effects on the transient temperature
responses in LDMOSFETs under the impact of a periodic
electromagnetic pulse},
Journal = {Ieee Transactions on Electron Devices},
Volume = {57},
Number = {1},
Pages = {345-352},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
Month = {January},
ISSN = {0018-9383},
url = {http://dx.doi.org/10.1109/TED.2009.2034995},
Abstract = {Thermal accumulation effects in an LDMOSFET under the impact
of a periodic electromagnetic pulse (EMP) are investigated
using time-domain finite-element method combined with the
preconditioned conjugated gradient technique. The transient
thermal response in the LDMOSFET and its peak temperature
are captured and compared, with different waveforms of the
injected EMP chosen for computation. It is shown that, as
the ratio of the pulsewidth and its periodicity increases,
thermal accumulation effects on the transient thermal
response as well as the peak temperature in LDMOSFETs are
observable, which should be treated appropriately in the
prediction of its electrothermal breakdown and reliability.
© 2009 IEEE.},
Doi = {10.1109/TED.2009.2034995},
Key = {fds283702}
}
@article{fds283705,
Author = {Chen, J and Liu, QH and Chai, M and Mix, JA},
Title = {A nonspurious 3-D vector discontinuous galerkin
finite-element time-domain method},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {20},
Number = {1},
Pages = {1-3},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
Month = {January},
ISSN = {1531-1309},
url = {http://dx.doi.org/10.1109/LMWC.2009.2035941},
Abstract = {We propose a nonspurious vector discontinuous Galerkin
finite-element time-domain (DG-FETD) method for 3-D
electromagnetic simulation. To facilitate the implementation
of numerical fluxes for domain decomposition, we construct
the DG-FETD scheme based on the first-order Maxwell's
equations with variables E and H. The LT/QN and the CT/LN
edge elements are employed to represent E and H,
respectively (or vice versa), to suppress spurious modes,
and the Riemann solver is utilized as the numerical flux to
correct fields on the interfaces between adjacent
subdomains. Numerical experiments show the nonspurious
property of the proposed method. © 2006
IEEE.},
Doi = {10.1109/LMWC.2009.2035941},
Key = {fds283705}
}
@article{fds283708,
Author = {Huang, YQ and Liu, YH and Liu, QH and Zhang, JZ},
Title = {Improved 3-D GPR detection by nufft combined with MPD
method},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {103},
Pages = {185-199},
Publisher = {EMW Publishing},
Year = {2010},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER10021005},
Abstract = {A combined method of the non-uniform fast fourier transform
(NUFFT) migration and the least-square based matching
pursuit decomposition (MPD) algorithms is proposed to obtain
better discrimination and interpretation for subsurface from
ground penetrating radar (GPR) signals. By using the
modified NUFFT migration algorithm, a fast and high
resolution GPR reconstruction can be obtained with an
additional reduction in storage and computation
requirements. By incorporating the MPD algorithm into a
migration method, denoised reconstructions are obtained to
enhance objects detection, including the identification of
objects' geometries and the estimation of their sizes and
locations. Several examples from synthetic data and field
data are demonstrated to establish the effectiveness of the
synergic effect by comparing it with the conventional
migration methods.},
Doi = {10.2528/PIER10021005},
Key = {fds283708}
}
@article{fds283717,
Author = {Rui, X and Hu, J and Liu, QH},
Title = {Fast inhomogeneous plane wave algorithm for analysis of
composite bodies of revolution},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {108},
Pages = {235-247},
Year = {2010},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER10081607},
Abstract = {A fast inhomogeneous plane wave algorithm is developed for
the electromagnetic scattering problem from the composite
bodies of revolution (BOR). Poggio-Miller-Chang-Harrington-Wu
(PMCHW) approach is used for the homogeneous dielectric
objects, while the electric field integral equation (EFIE)
is used for the perfect electric conducting objects. The
aggregation and disaggregation factors can be expressed
analytically by using the Weyl identity. Compared with the
traditional method of moments (MoM), both the memory
requirement and CPU time, are reduced for large-scale
composite BOR problems. Numerical results are given to
demonstrate the validity and the efficiency of the proposed
method.},
Doi = {10.2528/PIER10081607},
Key = {fds283717}
}
@article{fds283718,
Author = {Liu, Y and Nie, Z and Liu, QH},
Title = {A new method for the synthesis of nonuniform linear arrays
with shaped power patterns},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {107},
Pages = {349-363},
Publisher = {EMW Publishing},
Year = {2010},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER10060912},
Abstract = {Antenna arrays with shaped power patterns have many
applications in communications and radars. Many antenna
array synthesis techniques for shaped patterns have been
developed in the past years, and most of them deal only with
uniformly spaced arrays. In this paper, a new method is
proposed for the synthesis of nonuniform linear antenna
arrays with shaped power patterns. The proposed synthesis
method consists of three steps. First, we find a
satisfactory power pattern for the required radiation
characteristics by solving a constrained least-squares
problem which is obtained with the help of non-redundant
representation of squared magnitude of a linear array
factor. Then, we factorize the polynomial associated with
the power pattern by using polynomial rooting, and
consequently obtain the corresponding field patterns.
Finally, the forward-backward matrix pencil method is used
to obtain a nonuniform linear array with optimized
excitation magnitudes, phases and locations for a specific
choice of field patterns. The synthesized array has a
smaller number of elements than the one with uniformly
spaced elements for the same pattern performance. Several
synthesis experiments are conducted to validate the
effectiveness and advantages of the proposed synthesis
method.},
Doi = {10.2528/PIER10060912},
Key = {fds283718}
}
@article{fds283719,
Author = {Zhu, CH and Liu, QH and Shen, Y and Liu, LJ},
Title = {A high accuracy conformal method for evaluating the
discontinuous fourier transform},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {109},
Pages = {425-440},
Publisher = {EMW Publishing},
Year = {2010},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER10082007},
Abstract = {A highly accurate, fast algorithm is proposed to evaluate
the finite Fourier transform of both continuous and
discontinues functions. As the discretization is conformal
to the function discontinuities, this method is called the
conformal Fourier transform (CFT) method. It is applied to
computational electromagnetics to calculate the Fourier
transform of induced electric current densities in a volume
integral equation. The spectral discrimination in the CFT
method can be arbitrary and the spectral range can be as
large as needed. As no discretization for the Fourier
exponential kernel is needed, the CFT method is not
restricted by the Nyquist sampling theorem, thus avoiding
the aliasing distortions that exist in other traditional
methods. The accuracy of the CFT method is greatly improved
since the method is based on high order interpolation and
the closed-form Fourier transforms for polynomials partly
reduce the error due to discretization. Assuming Ns and N
are the numbers of sampling points in the spatial and
spectral domains, respectively, the computational cost of
the CFT method is O((M + 1)N log2 L), where M is the
interpolation order and L = Ns-1/M. Applications in the
spectral analysis of electromagnetic fields are
demonstrated.},
Doi = {10.2528/PIER10082007},
Key = {fds283719}
}
@article{fds283729,
Author = {Rui, X and Hu, J and Liu, QH},
Title = {Fast inhomogeneous plane wave algorithm for homogeneous
dielectric body of revolution},
Journal = {Communications in Computational Physics},
Volume = {8},
Number = {4},
Pages = {917-932},
Publisher = {Global Science Press},
Year = {2010},
Month = {January},
ISSN = {1815-2406},
url = {http://dx.doi.org/10.4208/cicp.220909.141209a},
Abstract = {To solve the electromagnetic scattering problem for
homogeneous dielectric bodies of revolution (BOR), a fast
inhomogeneous plane wave algorithm is developed. By using
the Weyl identity and designing a proper integration path,
the aggregation and disaggregation factors can be derived
analytically. Compared with the traditional method ofmoments
(MoM), both thememory and CPU time requirements are reduced
for large-scale homogeneous dielectric BOR problems.
Numerical results are given to demonstrate the validity and
the efficiency of the proposed method. © 2010
Global-Science Press.},
Doi = {10.4208/cicp.220909.141209a},
Key = {fds283729}
}
@article{fds283780,
Author = {Yu, C and Yuan, M and Zhang, Y and Stang, J and George, RT and Ybarra, GA and Joines, WT and Liu, QH},
Title = {Microwave imaging in layered media: 3-D image reconstruction
from experimental data},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {58},
Number = {2},
Pages = {440-448},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2010},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2009.2037770},
Abstract = {A prototype microwave imaging system for imaging 3-D targets
in layered media is developed to validate the capability of
microwave imaging with experimental data and with 3-D
nonlinear inverse scattering algorithms. In this
experimental prototype, the transmitting and receiving
antennas are placed in a rectangular tub containing a fluid.
Two plastic slabs are placed in parallel in the fluid to
form a five-layer medium. The microwave scattering data are
acquired by mechanically scanning a single transmitting
antenna and a single receiving antenna, thus avoiding the
mutual coupling that occurs when an array is used. The
collected 3-D experimental data in the fluid are processed
by full 3-D nonlinear inverse scattering algorithms to
unravel the complicated multiple scattering effects and
produce 3-D digital images of the dielectric constant and
conductivity of the imaging domain. The image reconstruction
is focused on the position and dimensions of the unknown
scatterers. Different dielectric and metallic objects have
been imaged effectively at 1.64 GHz. © 2006
IEEE.},
Doi = {10.1109/TAP.2009.2037770},
Key = {fds283780}
}
@article{fds283689,
Author = {Simsek, E and Liu, QH},
Title = {Integral equation solvers and their applications in the
optical regime},
Journal = {Proceedings of the 2009 International Conference on
Electromagnetics in Advanced Applications, Iceaa
'09},
Pages = {230-233},
Publisher = {IEEE},
Year = {2009},
Month = {December},
url = {http://dx.doi.org/10.1109/ICEAA.2009.5297473},
Abstract = {This paper presents integral equation solvers to calculate
the electromagnetic field scattered from objects embedded in
a multilayered medium. First, the electric field surface
integral equation (SIE) is solved using method of moments
for homogeneous objects. Then, this SIE is used as an exact
radiation boundary condition to truncate the computational
domain in the finite-element method (FEM) to form a hybrid
SIE-FEM, which is applicable to arbitrary inhomogeneous
objects embedded in a multilayered medium. The efficiency
and accuracy of the developed methods have been demonstrated
with numerical experiments both in microwave and optical
regimes. © 2009 IEEE.},
Doi = {10.1109/ICEAA.2009.5297473},
Key = {fds283689}
}
@article{fds283690,
Author = {Leong, HS and Guo, J and Lindquist, RG and Liu, QH},
Title = {Surface plasmon resonance in nanostructured metal films
under the Kretschmann configuration},
Journal = {Journal of Applied Physics},
Volume = {106},
Number = {12},
Pages = {124314-124314},
Publisher = {AIP Publishing},
Year = {2009},
Month = {December},
ISSN = {0021-8979},
url = {http://hdl.handle.net/10161/3321 Duke open
access},
Abstract = {We systematically investigated the surface plasmon resonance
in one-dimensional (1D) subwavelength nanostructured metal
films under the Kretschmann configuration. We calculated the
reflectance, transmittance, and absorption for varying the
dielectric fill factor, the period of the 1D nanostructure,
and the metal film thickness. We have found that the small
dielectric slits in the metal films reduce the surface
plasmon resonance angle and move it toward the critical
angle for total internal reflection. The reduction in
surface plasmon resonance angle in nanostructured metal
films is due to the increased intrinsic free electron
oscillation frequency in metal nanostructures. Also we have
found that the increasing the spatial frequency of the 1D
nanograting reduces the surface plasmon resonance angle,
which indicates that less momentum is needed to match the
momentum of the surface plasmon-polariton. The variation in
the nanostructured metal film thickness changes the
resonance angle slightly, but mainly remains as a mean to
adjust the coupling between the incident optical wave and
the surface plasmon-polariton wave. © 2009 American
Institute of Physics.},
Doi = {10.1063/1.3273359},
Key = {fds283690}
}
@article{fds283691,
Author = {Gong, W and Chen, G and Zhao, Z and Nie, Z and Liu, QH},
Title = {Amplitude characteristics of microwave induced
thermoacoustic signals},
Journal = {Iet Conference Publications},
Volume = {2009},
Number = {557 CP},
Pages = {464-467},
Publisher = {IET},
Year = {2009},
Month = {December},
url = {http://dx.doi.org/10.1049/cp.2009.1328},
Abstract = {When pulsed radio-frequency (RF) or pulsed microwave
irradiation is absorbed by biological tissue, the expansion
of the heated tissue, derived from the absorption of
electromagnetic energy, leads to an instantaneous acoustic
stress or pressure distribution inside the tissue, which
prompting wave propagation toward the surface of the tissue.
In this paper, we present a theoretical analysis of the
amplitude characteristics of microwave induced
thermoacoustic (MITA) signals based on the thermal equation
and dynamical equation. Then a brief introduction to the
prototype of MITA tomography experimental system is given.
And two groups of experiment have been carried out. The
experimental results are used to validate the theoretical
analysis and also may be employed to evaluate the limitation
of microwave power for safety reasons as well as the
availability of signals for reconstruction.},
Doi = {10.1049/cp.2009.1328},
Key = {fds283691}
}
@article{fds283692,
Author = {Yang, S and Liu, Y and Liu, QH},
Title = {Combined strategies based on matrix pencil method and tabu
search algorithm to minimize elements of non-uniform antenna
array},
Journal = {Progress in Electromagnetics Research B. Pier
B},
Volume = {18},
Number = {18},
Pages = {259-277},
Publisher = {EMW Publishing},
Year = {2009},
Month = {December},
ISSN = {1937-6472},
url = {http://dx.doi.org/10.2528/PIERB09092408},
Abstract = {The minimization of elements in a non-uniform antenna array
is critical in some practical engineering applications such
as satellite and mobile communications. However, due to the
complexity in the synthesis of an antenna array, the
available techniques are not equally successful for reducing
the element number of a non-uniform antenna array with as
few elements as possible with respect to both solution
quality and solution efficiency. In this point of view, a
combined strategy based on the matrix pencil method and tabu
search algorithm is proposed with the goal of integrating
the advantages of the high solution efficiency of the matrix
pencil method and the strong global searching ability of the
tabu search algorithm when solving an antenna array design
problem. In the proposed strategies, the desired radiation
pattern is firstly sampled to form a discrete pattern data
set. The matrix pencil method is then employed to optimize
the excitations and location distributions of the antenna
array elements to reduce the element number. Finally, the
excitation and location distributions of antenna array
elements are (repeatedly) re-optimized by using a tabu
search algorithm by starting from the solution of the matrix
pencil method to efficiently find the global solution of the
design problem. To make the tabu search algorithm suitable
for solving antenna array designs, some innovative
approaches such as the elimination of the tabu list,
systematic diversification as well as intensification
processes for neighborhood creations are made. Numerical
examples have shown the effectiveness and advantages of the
proposed combined strategies.},
Doi = {10.2528/PIERB09092408},
Key = {fds283692}
}
@article{fds283693,
Author = {Chen, J and Lee, JH and Liu, QH},
Title = {A high-precision integration scheme for the spectral-element
time-domain method in electromagnetic simulation},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {57},
Number = {10 PART 2},
Pages = {3223-3231},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {December},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2009.2028633},
Abstract = {A high-precision integration (HPI) scheme combined with the
spectral-element time-domain (SETD) method is presented to
solve the time-dependent Maxwell's equations. Spatial
discretization by spectral elements will lead to block
diagonal mass matrices, thus greatly alleviating the
computational burden of inverting the mass matrices. A
high-precision time integration method based on the matrix
exponential is then employed to solve the discretized SETD
system. Numerical examples demonstrate that this algorithm
is unconditionally stable and very accurate. © 2009
IEEE.},
Doi = {10.1109/TAP.2009.2028633},
Key = {fds283693}
}
@article{fds283704,
Author = {Chen, GP and Zhao, ZQ and Gong, W and Nie, ZP and Liu,
QH},
Title = {Development of microwave-induced thermo-acoustic tomography
prototype system},
Journal = {Chinese Science Bulletin},
Volume = {54},
Number = {23},
Pages = {4446-4450},
Publisher = {Elsevier BV},
Year = {2009},
Month = {December},
ISSN = {1001-6538},
url = {http://dx.doi.org/10.1007/s11434-009-0180-9},
Abstract = {Due to its advantages in both contrast and resolution
compared with conventional microwave or ultrasound imaging
system, microwave-induced thermo-acoustic tomography (MITAT)
has received more and more concerns in biologic tissue image
field. In this paper, an integrated prototype of MITAT
system is presented. Using this system, some basic
experiments for biologic tissue objects with high
water-content imbedded in fatty material have been done. In
the MITAT experiments, the signals generated by two porcine
muscle tissue strips with millimeter order scale in
cross-section were collected. Images with both good contrast
and resolution were obtained. In order to demonstrate the
advantages of MITAT, some ultrasonic experiments were
studied using a commercial ultrasonic linear array system.
The comparisons of the results of both systems show the good
performance of the MITAT prototype system for the detection
of high water content targets, which is generally the same
as the tumor in biologic tissue. © 2009 Science in China
Press and Springer Berlin Heidelberg.},
Doi = {10.1007/s11434-009-0180-9},
Key = {fds283704}
}
@article{fds283683,
Author = {Zhao, Y and Dai, G and Tang, Y and Liu, Q},
Title = {Symplectic discretization for spectral element solution of
Maxwell's equations},
Journal = {Journal of Physics A: Mathematical and Theoretical},
Volume = {42},
Number = {32},
Pages = {325203-325203},
Publisher = {IOP Publishing},
Year = {2009},
Month = {November},
ISSN = {1751-8113},
url = {http://dx.doi.org/10.1088/1751-8113/42/32/325203},
Abstract = {Applying the spectral element method (SEM) based on the
Gauss-Lobatto-Legendre (GLL) polynomial to discretize
Maxwell's equations, we obtain a Poisson system or a Poisson
system with at most a perturbation. For the system, we prove
that any symplectic partitioned Runge-Kutta (PRK) method
preserves the Poisson structure and its implied symplectic
structure. Numerical examples show the high accuracy of SEM
and the benefit of conserving energy due to the use of
symplectic methods. © 2009 IOP Publishing
Ltd.},
Doi = {10.1088/1751-8113/42/32/325203},
Key = {fds283683}
}
@article{fds283684,
Author = {Wang, J and Yin, WV and Liu, QH},
Title = {A new interface treatment technique for modeling curved
dielectric objects},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2009},
Month = {November},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2009.5171797},
Doi = {10.1109/APS.2009.5171797},
Key = {fds283684}
}
@article{fds283685,
Author = {Liu, QF and Yin, WV and Liu, QH},
Title = {Efficient approaches to improve the shielding effectiveness
of metallic enclosure with apertures},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2009},
Month = {November},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2009.5171800},
Doi = {10.1109/APS.2009.5171800},
Key = {fds283685}
}
@article{fds283686,
Author = {Yu, C and Yuan, M and Liu, QH},
Title = {Reconstruction of 3-D dielectric objects from measured
data},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2009},
Month = {November},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2009.5171681},
Doi = {10.1109/APS.2009.5171681},
Key = {fds283686}
}
@article{fds283687,
Author = {Liu, QH},
Title = {Application of PML to electromagnetics, acoustics,
elasticity, and quantum mechanics},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2009},
Month = {November},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2009.5172204},
Doi = {10.1109/APS.2009.5172204},
Key = {fds283687}
}
@article{fds283688,
Author = {Liu, Y and Nie, Z and Zhao, Z and Liu, QH},
Title = {A cascaded correction method to reduce the contamination of
ionospheric frequency modulation for hf skywave
radars},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2009},
Month = {November},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2009.5172385},
Doi = {10.1109/APS.2009.5172385},
Key = {fds283688}
}
@article{fds283703,
Author = {Luo, M and Liu, QH},
Title = {Spectral element method for band structures of
three-dimensional anisotropic photonic crystals.},
Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter
Physics},
Volume = {80},
Number = {5 Pt 2},
Pages = {056702},
Year = {2009},
Month = {November},
ISSN = {1539-3755},
url = {http://dx.doi.org/10.1103/physreve.80.056702},
Abstract = {A spectral element method (SEM) is introduced for accurate
calculation of band structures of three-dimensional
anisotropic photonic crystals. The method is based on the
finite-element framework with curvilinear hexahedral
elements. Gauss-Lobatto-Legendre polynomials are used to
construct the basis functions. In order to suppress spurious
modes, mixed-order vector basis functions are employed and
the Bloch periodic boundary condition is imposed into the
basis functions with tangential components at the boundary
by multiplying a Bloch phase factor. The fields and
coordinates in the curvilinear hexahedral elements are
mapped to the reference domain by covariant mapping, which
preserves the continuity of tangential components of the
field. Numerical results show that the SEM has exponential
convergence for both square-lattice and triangular-lattice
photonic crystals. The sampling density as small as 3.4
points per wavelength can achieve accuracy as high as 99.9%.
The band structures of several modified woodpile photonic
crystals are calculated by using the SEM.},
Doi = {10.1103/physreve.80.056702},
Key = {fds283703}
}
@article{fds283700,
Author = {Liu, QF and Yin, WY and Tang, M and Liu, PG and Mao, JF and Liu,
QH},
Title = {Time-domain investigation on cable-induced transient
coupling into metallic enclosures},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {51},
Number = {4},
Pages = {953-962},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {November},
ISSN = {0018-9375},
url = {http://dx.doi.org/10.1109/TEMC.2009.2029347},
Abstract = {A hybrid time-domain method is proposed for characterizing
electromagnetic interference (EMI) signals coupled into some
composite structures with metallic enclosures, braided
shielded cable, printed circuit boards, and even lumped
active devices. In order to rapidly capture the induced
interior EMI, the finite-difference time-domain, modified
node analysis, and multiconductor transmission lines methods
are combined together and implemented successfully.
Numerical investigation is carried out to demonstrate the
frequency-dependent transfer impedance of the coaxial cable,
the induced voltage at the place of active loaded element in
the transmission line network, and the enclosure shielding
effectiveness of these composite enclosures. The captured
transient response information is useful for further
designing electromagnetic protection of the inner circuits
against the impact of voltage or current surge caused by
nonintentional as well as intentional electromagnetic
interference. © 2006 IEEE.},
Doi = {10.1109/TEMC.2009.2029347},
Key = {fds283700}
}
@article{fds283701,
Author = {Chen, WC and Yin, WY and Jia, L and Liu, QH},
Title = {Electrothermal characterization of single-walled carbon
nanotube (SWCNT) interconnect arrays},
Journal = {Ieee Transactions on Nanotechnology},
Volume = {8},
Number = {6},
Pages = {718-728},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {November},
ISSN = {1536-125X},
url = {http://dx.doi.org/10.1109/TNANO.2009.2019725},
Abstract = {Electrothermal characterization of a metallic single-walled
carbon nanotube (SWCNT) interconnect array is performed in
this paper. The array is biased by a high voltage or under
the impact of an electrostatic discharge pulse current.
Using both time-dependent and -independent finite-difference
methods, 1-D longitudinal heat conduction equation of SWCNT
in the array is first solved, with CNT length-dependent
temperature distribution, breakdown voltage, power handling
capability, as well as transient thermal response captured
and compared. Two modified equivalent electrothermal circuit
models of a single SWCNT and an SWCNT array are proposed to
accurately characterize hybrid effects of the biasing
voltage, CNT length, and maximum rise in temperature. Their
electrothermal circuit models are further implemented for
investigating self-heating impact on signal integrities of
SWCNT interconnect arrays, in particular, time-delay-induced
crosstalk and noise. It is theoretically demonstrated that
self-heating effect should be considered carefully in the
design of local SWCNT interconnects when a high biasing
signal voltage is applied. © 2006 IEEE.},
Doi = {10.1109/TNANO.2009.2019725},
Key = {fds283701}
}
@article{fds283772,
Author = {Lin, Y and Lee, JH and Liu, J and Chai, M and Mix, JA and Liu,
QH},
Title = {A hybrid SIM-SEM method for 3-D electromagnetic scattering
problems},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {57},
Number = {11},
Pages = {3655-3663},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {November},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2009.2026664},
Abstract = {A new method combining the spectral integral method and
spectral element method (SIM-SEM) is proposed to simulate
3-D electromagnetic scattering from inhomogeneous objects.
In this hybrid technique (a special case of the finite
element boundary integral (FEM-BI) combination), the SEM
with the mixed-order curl conforming vector
Gauss-Lobatto-Legendre (GLL) basis functions are used to
represent the interior electric field with high accuracy,
while the SIM on a cuboid surface is used as an exact
radiation boundary condition. The Toeplitz property of the
SIM matrix is utilized to reduce the memory and CPU time
costs in an iterative solver by using the fast Fourier
transform algorithm. Unlike the traditional FEM-BI
combination where the BI portion usually dominates the
computational complexity, the computational costs are much
lower in the SIM-SEM method. Numerical results verify the
accuracy and capability of this method, confirming that the
SIM-SEM method is a good alternative for solving scattering
problems from inhomogeneous objects. © 2006
IEEE.},
Doi = {10.1109/TAP.2009.2026664},
Key = {fds283772}
}
@article{fds283681,
Author = {Yu, C and Yuan, M and Liu, QH},
Title = {Reconstruction of 3D objects from multi-frequency
experimental data with a fast DBIM-BCGS method},
Journal = {Inverse Problems},
Volume = {25},
Number = {2},
Pages = {024007-024007},
Publisher = {IOP Publishing},
Year = {2009},
Month = {October},
ISSN = {0266-5611},
url = {http://dx.doi.org/10.1088/0266-5611/25/2/024007},
Abstract = {The objective of this work is to perform image
reconstruction of 3D dielectric targets from multi-frequency
experimental data by using a fast DBIM-BCGS method that
combines the distorted Born iterative method (DBIM) and the
stabilized biconjugate-gradient fast Fourier transform
(BCGS-FFT) method. In this reconstruction technique, the
BCGS-FFT method is used as a forward scattering method for
solving the volume integral equations governing the 3D
scattering problem; it provides both the predicted scattered
fields due to 3D heterogeneous objects and the Fréchet
derivatives in the inverse scattering problem. The
plane-wave source model and the point receiver model are
used in the inversion procedure to invert the calibrated
scattering data obtained from Institut Fresnel's
measurements. The multi-frequency experimental data are
processed with the frequency-hopping approach to obtain
high-resolution 3D images. The reconstruction of five
different targets from the measured scattered fields
verifies the capability and the effectiveness of the
DBIM-BCGS method. © 2009 IOP Publishing
Ltd.},
Doi = {10.1088/0266-5611/25/2/024007},
Key = {fds283681}
}
@article{fds283680,
Author = {Peng, Y and Qing, HL},
Title = {An improved MRI reconstruction method based on table-lookup
gridding},
Journal = {Proceedings of 2009 International Conference on Image
Analysis and Signal Processing, Iasp 2009},
Pages = {9-12},
Publisher = {IEEE},
Year = {2009},
Month = {October},
url = {http://dx.doi.org/10.1109/IASP.2009.5054637},
Abstract = {Radial encoding is often performed for fast data acquisition
in magnetic resonance imaging (MRI). Therefore, the gridding
method, which is a kind of algorithm for Fast Fourier
Transform, is widely used in fast MRI reconstruction. In
this paper, an improved gridding method has been utilized to
2D MRI reconstruction, which precomputes an 1D finely
sampled table of a high-accuracy interpolator and then uses
separable bilinear interpolation by look-up table.
Experimental comparisons are made by assessing the
performance of the direct reconstruction, the conventional
KB gridding and the proposed method. The experimental
results show that the proposed method provides high
accuracy, fast computation, and dramatic memory saving.
©2009 IEEE.},
Doi = {10.1109/IASP.2009.5054637},
Key = {fds283680}
}
@article{fds283679,
Author = {Lee, JH and Chen, J and Liu, QH},
Title = {A 3-D discontinuous spectral element time-domain method for
Maxwell's equations},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {57},
Number = {9},
Pages = {2666-2674},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {September},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2009.2027731},
Abstract = {A discontinuous spectral element time-domain method is
proposed to analyze transient electromagnetic properties of
general 3-D structures. This method is advantageous in that
its mass matrices are block-diagonal due to the
Gauss-Lobatto-Legendre polynomials, and it allows different
orders of basis functions for each subdomain. The Riemann
solver is employed in the boundary integral terms to
communicate fields between adjacent subdomains. Perfectly
matched layers are utilized to truncate the computational
domain. Galerkin method is used for spatial discretization,
and a fourth-order Runge-Kutta scheme is employed for the
time integration. The validity of the proposed approach is
demonstrated through several numerical examples of initial
value problems and scattering problems. © 2009
IEEE.},
Doi = {10.1109/TAP.2009.2027731},
Key = {fds283679}
}
@article{fds283698,
Author = {Chen, G and Zhao, Z and Zheng, W and Nie, Z and Liu,
Q},
Title = {Application of time reversal mirror technique in
microwave-induced thermo-acoustic tomography
system},
Journal = {Science in China Series E: Technological
Sciences},
Volume = {52},
Number = {7},
Pages = {2087-2095},
Publisher = {Springer Nature},
Year = {2009},
Month = {July},
ISSN = {1006-9321},
url = {http://dx.doi.org/10.1007/s11431-009-0148-7},
Abstract = {Microwave-induced thermo-acoustic tomography (MITAT) is a
promising technique with great potential in biomedical
imaging. It has both the high contrast of the microwave
imaging and the high resolution of the ultrasound imaging.
In this paper, the proportional relationship between the
absorbed microwave energy distribution and the induced
ultrasound source distribution is derived. Further, the time
reversal mirror (TRM) technique based on the pseudo-spectral
time domain (PSTD) method is applied to MITAT system. The
simulation results show that high contrast and resolution
can be achieved by the TRM technique based on PSTD method
even for the received signals with very low signal-to-noise
ratio (SNR) and the model parameter with random fluctuation.
© 2009 Science in China Press and Springer-Verlag
GmbH.},
Doi = {10.1007/s11431-009-0148-7},
Key = {fds283698}
}
@article{fds283699,
Author = {Luo, M and Liu, QH},
Title = {Accurate determination of band structures of two-dimensional
dispersive anisotropic photonic crystals by the spectral
element method.},
Journal = {Journal of the Optical Society of America
A},
Volume = {26},
Number = {7},
Pages = {1598-1605},
Year = {2009},
Month = {July},
ISSN = {1084-7529},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19568295},
Abstract = {The spectral element method (SEM) is used to calculate band
structures of two-dimensional photonic crystals (PCs)
consisting of dispersive anisotropic materials. As in the
conventional finite element method, for a dispersive PC, the
resulting eigenvalue problem in the SEM is nonlinear and the
eigenvalues are in general complex frequencies. We develop
an efficient way of incorporating the dispersion in the
system matrices. The band structures of a PC with a square
lattice of dispersive cylindrical rods are first analyzed.
The imaginary part of the complex frequency is the
time-domain decay rate of the eigenmode, which is very
useful for tracing a band from discrete numerical data.
Modification of the band structure of TE mode by an external
static magnetic field in the out-of-plane direction is
explored for this square lattice. A plasmon resonance mode
is found near the plasmon frequency when the magnetic field
is nonzero. The band structure of a PC with a triangular
lattice is also calculated with the SEM. Other types of
lattices can also be treated readily by the
SEM.},
Doi = {10.1364/josaa.26.001598},
Key = {fds283699}
}
@article{fds283697,
Author = {Liu, QF and Yin, WY and Xue, MF and Mao, JF and Liu,
QH},
Title = {Shielding characterization of metallic enclosures with
multiple slots and a thin-wire antenna loaded: Multiple
oblique EMP incidences with arbitrary polarizations},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {51},
Number = {2},
Pages = {284-292},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {June},
ISSN = {0018-9375},
url = {http://dx.doi.org/10.1109/TEMC.2008.2011891},
Abstract = {Shielding effectiveness (SE) of metallic rectangular
enclosures with thin slots and a thin-wire antenna loaded by
an impedance, illuminated by multiple electromagnetic pulses
(EMPs) simultaneously, is investigated using a hybrid
finite-difference time-domain (FDTD) method. In order to
enhance the simulation efficiency of the FDTD algorithm,
accurate formulas for handling multiple thin slots, a
thin-wire antenna, and a lumped network are integrated
together. Numerical results show that for real metallic
enclosures, their shielding performance is very sensitive to
the variations in direction and polarization angle of the
incident EMPs. However, at a given frequency, the resistance
and inductance loaded at the terminal of a thin-wire antenna
have little effect on the SE level. For two, three, as well
as more EMP incidences, common-frequency interferences will
result in strong inner field resonance in the enclosure. ©
2009 IEEE.},
Doi = {10.1109/TEMC.2008.2011891},
Key = {fds283697}
}
@article{fds283677,
Author = {Shi, YB and Yin, WY and Mao, JF and Liu, P and Liu, QH},
Title = {Transient electrothermal analysis of multilevel
interconnects in the presence of ESD pulses using the
nonlinear time-domain finite-element method},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {51},
Number = {3 PART 2},
Pages = {774-783},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {April},
ISSN = {0018-9375},
url = {http://dx.doi.org/10.1109/TEMC.2009.2017026},
Abstract = {Comprehensive electrothermal analysis of multilevel
interconnects under electrostatic discharge (ESD) stress is
carried out using the proposed nonlinear time-domain
finite-element method (FEM). The technological, structural,
and material parameters used in the analysis correspond to
the advanced CMOS process of 90-, 65-, 45, and 32-nm nodes
assessed by the International Technology Roadmap for
Semiconductors. In order to enhance the computation
efficiency and to reduce the memory cost, the preconditioned
conjugated gradient technique combined with the
element-by-element approximate factorization method is
introduced to handle the sparse matrices formed by FEM. The
nonlinear material parameters including the
temperature-dependent electrical and thermal conductivities
are treated rigorously. The transient temperature
distributions, the maximum temperatures, and the temperature
rise time of 3- and 4-level interconnect structures under
the injection of ESD pulses with various waveforms are
obtained and discussed. © 2009 IEEE.},
Doi = {10.1109/TEMC.2009.2017026},
Key = {fds283677}
}
@article{fds283782,
Author = {Song, J and Liu, Y and Gewalt, SL and Cofer, G and Johnson, GA and Liu,
QH},
Title = {Least-square NUFFT methods applied to 2-D and 3-D radially
encoded MR image reconstruction.},
Journal = {Ieee Trans Biomed Eng},
Volume = {56},
Number = {4},
Pages = {1134-1142},
Year = {2009},
Month = {April},
url = {http://www.ncbi.nlm.nih.gov/pubmed/19174334},
Abstract = {Radially encoded MRI has gained increasing attention due to
its motion insensitivity and reduced artifacts. However,
because its samples are collected nonuniformly in the
k-space, multidimensional (especially 3-D) radially sampled
MRI image reconstruction is challenging. The objective of
this paper is to develop a reconstruction technique in high
dimensions with on-the-fly kernel calculation. It implements
general multidimensional nonuniform fast Fourier transform
(NUFFT) algorithms and incorporates them into a k-space
image reconstruction framework. The method is then applied
to reconstruct from the radially encoded k-space data,
although the method is applicable to any non-Cartesian
patterns. Performance comparisons are made against the
conventional Kaiser-Bessel (KB) gridding method for 2-D and
3-D radially encoded computer-simulated phantoms and
physically scanned phantoms. The results show that the NUFFT
reconstruction method has better accuracy-efficiency
tradeoff than the KB gridding method when the kernel weights
are calculated on the fly. It is found that for a particular
conventional kernel function, using its corresponding
deapodization function as a scaling factor in the NUFFT
framework has the potential to improve accuracy. In
particular, when a cosine scaling factor is used, the NUFFT
method is faster than KB gridding method since a closed-form
solution is available and is less computationally expensive
than the KB kernel (KB griding requires computation of
Bessel functions). The NUFFT method has been successfully
applied to 2-D and 3-D in vivo studies on small
animals.},
Doi = {10.1109/TBME.2009.2012721},
Key = {fds283782}
}
@article{fds283673,
Author = {Luo, M and Liu, QH and Li, Z},
Title = {Two-dimensional Green's function tensor and projected local
density of states for TM and TE modes in dispersive and
anisotropic photonic crystals},
Journal = {Waves in Random and Complex Media},
Volume = {19},
Number = {1},
Pages = {28-38},
Publisher = {Informa UK Limited},
Year = {2009},
Month = {March},
ISSN = {1745-5030},
url = {http://dx.doi.org/10.1080/17455030802452285},
Abstract = {A multiple-scattering method for two-dimensional TM modes is
extended to calculate the electric Green's function tensor
for TE modes of a finite-size photonic crystal consisting of
infinite-length cylinders of dispersive and in-plane
anisotropic materials. We investigate the frequency and
spatial dependence of the projected local density of states
for TM and TE modes of the system. The large enhancement
factor of the projected local density of states has been
observed for dispersive finite photonic crystals.},
Doi = {10.1080/17455030802452285},
Key = {fds283673}
}
@article{fds283695,
Author = {Yang, S and Liu, QH and Lu, J and Ho, SL and Ni, G and Ni, P and Xiong,
S},
Title = {Application of support vector machines to accelerate the
solution speed of metaheuristic algorithms},
Journal = {Ieee Transactions on Magnetics},
Volume = {45},
Number = {3},
Pages = {1502-1505},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {March},
ISSN = {0018-9464},
url = {http://dx.doi.org/10.1109/TMAG.2009.2012690},
Abstract = {The support vector machine (SVM) is proposed as a response
surface model to accelerate the solution speed of
metaheuristic algorithms in solving inverse problems. The
detail formulations of the SVM regression model using
$\varepsilon$-insensitive loss function are derived. Primary
numerical results are reported to demonstrate the
feasibility, performance, and robustness of the proposed SVM
based response surface model for solving both mathematical
functions and engineering design problems. © 2006
IEEE.},
Doi = {10.1109/TMAG.2009.2012690},
Key = {fds283695}
}
@article{fds283696,
Author = {Nie, ZP and Yu, WB and Chen, GP and Zhao, ZQ and Liu,
QH},
Title = {Preliminary study on microwave-induced thermo-acoustic
tomography system},
Journal = {Dianzi Keji Daxue Xuebao/Journal of the University of
Electronic Science and Technology of China},
Volume = {38},
Number = {2},
Pages = {218-221},
Year = {2009},
Month = {March},
ISSN = {1001-0548},
Abstract = {When biologic tissue is irradiated by microwave pulse, it
will generate thermo-acoustic signal due to heat expansion.
As the electric characters of normal mammary tissues and
malignant tumors are quite different, the detection
probability of early-stage malignant tumors under microwave
irradiation will be greatly improved. In this paper, the
principle of the microwave-induced thermo-acoustic
tomography (MITAT) system is briefly introduced. The factors
which affect the resolution are discussed. Some preliminary
imaging results have been obtained using the data generated
by a simple sample under a homogeneous environment.},
Key = {fds283696}
}
@article{fds283675,
Author = {Pu, SN and Yin, WY and Mao, JF and Liu, QH},
Title = {Crosstalk prediction of single- and double-walled
carbon-nanotube (SWCNT/ DWCNT) bundle interconnects},
Journal = {Ieee Transactions on Electron Devices},
Volume = {56},
Number = {4},
Pages = {560-568},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {February},
ISSN = {0018-9383},
url = {http://dx.doi.org/10.1109/TED.2009.2014429},
Abstract = {The crosstalk effects in single- and double-walled
carbon-nanotube (SWCNT and DWCNT) bundle-interconnect
architectures are investigated in this paper. Some modified
equivalent-circuit models are proposed for both SWCNT and
DWCNT bundles, where capacitive couplings between adjacent
bundles are incorporated. These circuit models are further
used to predict the performance of SWCNT and DWCNT bundle
interconnects in comparison with the Cu wire counterpart at
all interconnect levels for advanced future technology
generations. It is found that, compared with the SWCNT
bundle, the DWCNT bundle interconnect can lead to a
reduction of crosstalk-induced time delay, which will be
more significant with increasing bundle length, while the
peak voltage of the crosstalk-induced glitch in SWCNT and
DWCNT bundle interconnects is in the same order as that of
Cu wires. Due to the improvement in time delay, it is
numerically confirmed that the DWCNT bundle interconnect
will be more suitable for the next generation of
interconnect technology as compared with the SWCNT bundle
counterpart. © 2009 IEEE.},
Doi = {10.1109/TED.2009.2014429},
Key = {fds283675}
}
@article{fds283694,
Author = {Luo, M and Liu, QH and Li, Z},
Title = {Spectral element method for band structures of
two-dimensional anisotropic photonic crystals.},
Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter
Physics},
Volume = {79},
Number = {2 Pt 2},
Pages = {026705},
Year = {2009},
Month = {February},
ISSN = {1539-3755},
url = {http://dx.doi.org/10.1103/physreve.79.026705},
Abstract = {A spectral element method (SEM) is proposed for the accurate
calculation of band structures of two-dimensional
anisotropic photonic crystals. It uses Gauss-Lobatto-Legendre
polynomials as the basis functions in the finite-element
framework with curvilinear quadrilateral elements.
Coordination mapping is introduced to make the curved
quadrilateral elements conformal with the problem geometry.
Mixed order basis functions are used in the vector SEM for
full vector calculation. The numerical convergence speed of
the method is investigated with both square and triangular
lattices, and with isotropic and in-plane anisotropic media.
It is shown that this method has spectral accuracy, i.e.,
the numerical error decreases exponentially with the order
of basis functions. With only four points per wavelength,
the SEM can achieve a numerical error smaller than 0.1%. The
full vector calculation method can suppress all spurious
modes with nonzero eigenvalues, thus making it easy to
filter out real modes. It is thus demonstrated that the SEM
is an efficient alternative method for accurate
determination of band structures of two-dimensional photonic
crystals.},
Doi = {10.1103/physreve.79.026705},
Key = {fds283694}
}
@article{fds283671,
Author = {Wang, J and Yin, WY and Liu, QH},
Title = {FDTD (2, 4)-compatible conformal technique for treatment of
dielectric surfaces},
Journal = {Electronics Letters},
Volume = {45},
Number = {3},
Pages = {146-147},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {2009},
Month = {February},
ISSN = {0013-5194},
url = {http://dx.doi.org/10.1049/el:20093215},
Abstract = {A modified conformal technique implemented in the high-order
finite-difference time-domain (FDTD) (2, 4) is proposed to
investigate the interaction of electromagnetic waves with
three-dimensional electrically large curved dielectric
objects. The proposed conformal technique uses an average
dielectric constant related to the area of different
dielectric regions in nine spatial discrete cells. It is
numerically demonstrated that the results obtained by this
new technique show good agreement with the results obtained
by the analytical method and some references, even with
coarse meshes adopted for handling electrically large
objects effectively. © The Institution of Engineering and
Technology.},
Doi = {10.1049/el:20093215},
Key = {fds283671}
}
@article{fds283771,
Author = {Liu, QH and Lin, Y and Liu, J and Lee, JH and Şimşek,
E},
Title = {A 3-D spectral integral method (SIM) for surface integral
equations},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {19},
Number = {2},
Pages = {62-64},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2009},
Month = {February},
ISSN = {1531-1309},
url = {http://dx.doi.org/10.1109/LMWC.2008.2011305},
Abstract = {An efficient 3-D spectral integral method (SIM) has been
proposed to speed up the method of moments (MOM) calculation
of induced currents on a cuboid. This method utilizes the
Toeplitz structure in the impedance matrix and the fast
Fourier transform to accelerate the MOM solution. It reduces
the memory and CPU time per iteration from O(N2) in the MOM
to O(N1.5) and O(N1.5 log N), respectively. Thus, the SIM
can be also used as an efficient radiation boundary
condition for the finite element method. Numerical results
confirm the effectiveness of this method. © 2006
IEEE.},
Doi = {10.1109/LMWC.2008.2011305},
Key = {fds283771}
}
@article{fds283573,
Author = {Chen, J and Liu, QH},
Title = {A non-spurious vector spectral element method for Maxwell's
equations},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {96},
Pages = {205-215},
Publisher = {EMW Publishing},
Year = {2009},
Month = {January},
ISSN = {1559-8985},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000271116200014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Abstract = {In this paper, a non-spurious vector spectral element method
is proposed to solve Maxwell's equations using E and H as
variables. The mixed-order curl-conforming basis functions
are used for both variables to facilitate applying boundary
and interface conditions; and the interpolation degree of
basis functions for E is set different from that for H to
suppress the spurious modes. The proposed method can be
utilized in both time domain and frequency domain, and it is
very suitable for the future implementation of discontinuous
Galerkin spectral element method. Numerical results
demonstrate the property of spurious-free and the spectral
accuracy of this method. The method has also been
implemented for the more general finite element method in
time and frequency domains.},
Doi = {10.2528/PIER09082705},
Key = {fds283573}
}
@article{fds283674,
Author = {Zheng, WJ and Zhao, ZQ and Nie, ZP and Liu, QH},
Title = {Evaluation of trm in the complex through wall
environment},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {90},
Pages = {235-254},
Publisher = {EMW Publishing},
Year = {2009},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER09011003},
Abstract = {Practical interests arising from behind-the-wall target
detection, surveillance and reconnaissance et al. claim for
high capability of imaging in complicated environments. Time
Reversal Mirror (TRM) technique, making use of the principle
of reciprocity, emerges as a promising way to deal with such
complex problem. In this paper, we investigate TRM in the
ultra-wideband (UWB) through wall radar imaging (TWRI)
through numerical simulation. The probing region is a square
room, with walls of rough surface and random media
parameters. TRM is used to image the target settled in the
room. We evaluate the degradation of the images when the
aperture of the array is decreased or the received signals
are contaminated by noises. The back projection (BP)
algorithm is employed here as a comparison for imaging
quality. For the case in which the random walls are changed
between the forward and inverse phase of time reversal, we
check the imaging stability and applied an averaged Green's
function to improve the imaging quality. Finally, some
interesting conclusions are drawn.},
Doi = {10.2528/PIER09011003},
Key = {fds283674}
}
@article{fds283678,
Author = {Liu, YH and Liu, QH and Nie, ZP},
Title = {A new efficient FDTD time-to-frequency-domain conversion
algorithm},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {92},
Pages = {33-46},
Publisher = {EMW Publishing},
Year = {2009},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER09030906},
Abstract = {The time-to-frequency-domain conversion is often required in
many applications of the finite-difference time-domain
(FDTD) method. This paper presents a new FDTD
time-to-frequency- domain conversion algorithm based on the
optimization of nonuniform fast Fourier transform (NUFFT)
with several redundancy-reduction techniques. The proposed
algorithm can perform the FDTD conversion at multiple
desired frequencies without the limitation of uniformly
spaced frequencies in the fast Fourier transform (FFT). In
addition, with a very low storage cost, the algorithm can be
much more efficient than other FDTD conversion techniques if
a moderate number of frequencies or more are of interest.
This algorithm is very useful for some FDTD
applications.},
Doi = {10.2528/PIER09030906},
Key = {fds283678}
}
@article{fds283682,
Author = {Yu, J and Yuan, M and Liu, QH},
Title = {A wideband half oval patch antenna for breast
imaging},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {98},
Pages = {1-13},
Publisher = {EMW Publishing},
Year = {2009},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.2528/PIER09090304},
Abstract = {A simple half oval patch antenna is proposed for the active
breast cancer imaging over a wide bandwidth. The antenna
consists of a half oval and a trapezium, with a total length
15.1mm and is fed by a coaxial cable. The antenna
performance is simulated and measured as immersed in a
dielectric matching medium. Measurement and simulation
results show that it can obtain a return loss less than
-10dB from 2.7 to 5GHz. The scattered field detection
capability is also studied by simulations of two opposite
placed antennas and a full antenna array on a cubic
chamber.},
Doi = {10.2528/PIER09090304},
Key = {fds283682}
}
@article{fds283779,
Author = {Stang, JP and Joines, WT and Liu, QH and Ybarra, GA and George, RT and Yuan, M and Leonhardt, I},
Title = {A tapered microstrip patch antenna array for use in breast
cancer screening via 3D active microwave
imaging},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Publisher = {IEEE},
Year = {2009},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2009.5171907},
Doi = {10.1109/APS.2009.5171907},
Key = {fds283779}
}
@article{fds283660,
Author = {Kong, FZ and Yin, WY and Mao, JF and Liu, QH},
Title = {Electro-thermo-mechanical investigation on multi-level
interconnects in the presence of an ESD pulse},
Journal = {2008 Electrical Design of Advanced Packaging and Systems
Symposium, Ieee Edaps 2008 Proceedings},
Pages = {167-170},
Publisher = {IEEE},
Year = {2008},
Month = {December},
url = {http://dx.doi.org/10.1109/EDAPS.2008.4736026},
Abstract = {Electro-thermo-meehanical transient investigation on
multi-layer high-density interconnects in the presence of an
ESD pulse is carried out using hybrid nonlinear time-domain
finite element method (FEM). The pre-conditioned conjugated
gradient technique (PCG) is combined with the
element-by-element FEM so as to enhance our numerical
analysis, where the temperature dispersion effects of
electrical conductivity, thermal conductivity, coefficient
of thermal expansion, and Young's modulus of the materials
involved are all taken into account. Parasitic studies are
performed to show time-dependent von Mises stress responses
of some typical interconnects as the injection of an ESD
current pulse, which can be fabricated using advanced
semiconductor technologies, such as 90-, 60, and even 45-nm
CMOS, etc. © 2008 IEEE.},
Doi = {10.1109/EDAPS.2008.4736026},
Key = {fds283660}
}
@article{fds283662,
Author = {Kong, FZ and Yin, WY and Mao, JF and Liu, QH},
Title = {Transient electro-thermo-mechanical responses of wire
bonding interconnects illuminated by an electromagnetic
pulse},
Journal = {Proceedings of 2008 Asia Pacific Microwave Conference, Apmc
2008},
Publisher = {IEEE},
Year = {2008},
Month = {December},
url = {http://dx.doi.org/10.1109/APMC.2008.4958006},
Abstract = {Time-dependent electro-thermo-mechanical transient
characterizations of wire bonding interconnects illuminated
by an electromagnetic pulse are investigated in this paper.
in the mathematical implementation, a hybrid time-domain
finite element method is applied to simulate mutual
interactions among electrical, thermal, and mechanical
fields, with all nonlinearities of temperature-dependent
electrical conductivities, thermal conductivities, thermal
expansion coefficients, and even the Young's modulus of
materials being treated appropriately. Therefore,
three-dimensional (3-D) temperature and thermal stress
distributions of single, serial and parallel wire bonding
interconnects used for connecting high power RF transistors
are captured numerically and discussed. ©2008
IEEE.},
Doi = {10.1109/APMC.2008.4958006},
Key = {fds283662}
}
@article{fds283663,
Author = {Wang, J and Yin, WY and Liu, QH},
Title = {A modified high-order FDTD conformal technique for modeling
perfectly conducting objects},
Journal = {Proceedings of 2008 Asia Pacific Microwave Conference, Apmc
2008},
Publisher = {IEEE},
Year = {2008},
Month = {December},
url = {http://dx.doi.org/10.1109/APMC.2008.4958451},
Doi = {10.1109/APMC.2008.4958451},
Key = {fds283663}
}
@article{fds283672,
Author = {Chen, G and Zhao, Z and Nie, Z and Liu, QH},
Title = {Computational study of time reversal mirror technique for
microwave-induced thermo-acoustic tomography},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {22},
Number = {16},
Pages = {2191-2204},
Publisher = {Informa UK Limited},
Year = {2008},
Month = {December},
ISSN = {0920-5071},
url = {http://dx.doi.org/10.1163/156939308787522555},
Abstract = {Microwave-Induced Thermo-Acoustic Tomography (MITAT) is a
promising technique in biomedical imaging. It has
predominant advantages in both contrast and resolution
compared with conventional microwave or ultrasound imaging
system for malignant tumors. In this paper, Time Reversal
Mirror (TRM) imaging technique based on numeric method
Pseudo-Spectrum Time Domain (PSTD) for MITAT imaging is
studied computationally. The proportion relationship between
the deposited microwave energy and the induced
thermo-acoustic initial source is deduced by analytic
method. Due to the globe higher order character and the
efficiency, the PSTD method is employed to implement the
forward core of the TRM and to model the complex biologic
tissue. In order to illustrate the performance of the TRM
technique applied in MITAT, some thermo-acoustic objects
with different initial pressure distributions are simulated,
then designed and imaged by this technique to represent the
complex biologic tissue case in a random media. Under the
consideration of noise and the velocity parameter change of
the model, the contrast and resolution of the images
generated by using TRM technique based on PSTD method are
also studied. © 2008 VSP.},
Doi = {10.1163/156939308787522555},
Key = {fds283672}
}
@article{fds283851,
Author = {Chen, WC and Jia, L and Yin, WY and Liu, QH},
Title = {Electro-thermal characterization of single-walled carbon
nanotube (SWCNT) interconnect arrays},
Journal = {2008 Electrical Design of Advanced Packaging and Systems
Symposium, Ieee Edaps 2008 Proceedings},
Pages = {175-178},
Publisher = {IEEE},
Year = {2008},
Month = {December},
url = {http://dx.doi.org/10.1109/EDAPS.2008.4736028},
Abstract = {We investigate electro-thermal properties of metallic
single-walled carbon nanotube (SWCNT) interconnect arrays
biased by a signal voltage in this paper, where temperature
distribution, breakdown voltage, and current carrying
capability are captured by solving one-dimensional heat
conduction equation of the SWCNT. Two electro-thermal
equivalent circuit models of single SWCNT and a SWCNT array
are proposed to illustrate hybrid effects of SWCNT length,
biasing voltage, and temperature on their signal
integrities. Simulation results indicate that self-heating
effect should be considered carefully in the design of local
SWCNT array interconnect as it is biased by a high signal
voltage. © 2008 IEEE.},
Doi = {10.1109/EDAPS.2008.4736028},
Key = {fds283851}
}
@article{fds283659,
Author = {Chen, G and Yu, W and Zhao, Z and Nie, Z and Liu, QH},
Title = {The application of time reversal mirror based on
pseudo-spectrum time domain for microwave-induced
thermo-acoustic tomography},
Journal = {2008 Ieee International Symposium on Antennas and
Propagation and Usnc/Ursi National Radio Science Meeting,
Apsursi},
Publisher = {IEEE},
Year = {2008},
Month = {November},
url = {http://dx.doi.org/10.1109/APS.2008.4619690},
Doi = {10.1109/APS.2008.4619690},
Key = {fds283659}
}
@article{fds283661,
Author = {Kong, FZ and Yin, WY and Mao, JF and Liu, QH},
Title = {Hybrid physical field simulation: Transient
electro-thermo-mechanical responses of interwafer
interconnects under the impact of an EMP},
Journal = {2008 Ieee International Symposium on Antennas and
Propagation and Usnc/Ursi National Radio Science Meeting,
Apsursi},
Publisher = {IEEE},
Year = {2008},
Month = {November},
url = {http://dx.doi.org/10.1109/APS.2008.4619420},
Abstract = {Time-dependent electro-thermo-mechanical transient responses
of interwafer interconnects under the impact of an BMP are
investigated in this paper. The mathematical methodology is
based on hybrid physical field time-domain finite element
method (FEM), in which all nonlinearities of
temperature-dependent electrical conductivities, thermal
conductivities, thermal expansion coefficients, and even the
Young's modulus of materials involved are treated
rigorously. Therefore, three-dimensional (3-D) temperature
and thermal stress distributions of one- and two-level metal
bridge-vias in multi-level interwafer interconnects used for
high-density integration of ICs are captured numerically and
discussed. © 2008 IEEE.},
Doi = {10.1109/APS.2008.4619420},
Key = {fds283661}
}
@article{fds283670,
Author = {Liu, Y and Nie, Z and Liu, QH},
Title = {DIFFT: A fast and accurate algorithm for Fourier transform
integrals of discontinuous functions},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {18},
Number = {11},
Pages = {716-718},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2008},
Month = {November},
ISSN = {1531-1309},
url = {http://dx.doi.org/10.1109/LMWC.2008.2005162},
Abstract = {A new highly accurate fast algorithm is proposed for
computing the Fourier transform integrals of discontinuous
functions (DIFFT) by employing the analytical Fourier
transforms of Gauss-Chebyshev-Lobatto interpolation
polynomials and the scaled fast Fourier transform. This
algorithm can achieve the exponential accuracy for
evaluation of Fourier spectra at the whole frequency range
with a low computational complexity. Furthermore, the
algorithm allows the adaptive sampling densities for
different sections of a piecewise smooth function. Numerical
experiments are shown for the applications in computational
electromagnetics. © 2008 IEEE.},
Doi = {10.1109/LMWC.2008.2005162},
Key = {fds283670}
}
@article{fds283669,
Author = {Chen, GP and Yu, WB and Zhao, ZQ and Nie, ZP and Liu,
QH},
Title = {The prototype of microwave-induced thermo-acoustic
tomography imaging by time reversal mirror},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {22},
Number = {11-12},
Pages = {1565-1574},
Publisher = {Informa UK Limited},
Year = {2008},
Month = {October},
ISSN = {0920-5071},
url = {http://dx.doi.org/10.1163/156939308786390021},
Abstract = {Microwave-Induced Thermo-Acoustic Tomography (MITAT) is a
promising technique in biologic tissue imaging. It has
predominant advantages in both contrast and resolution
compared with conventional microwave or ultrasound imaging
system for malignant tumors. In this paper, an integrated
prototype MITAT system is briefly introduced. And Time
Reversal Mirror (TRM) imaging technique based on
Pseudo-Spectrum Time Domain (PSTD) is also first time
applied to MITAT system. Two tissue strips of porcine muscle
are used as targets in the MITAT experiment to demonstrate
the imaging potential of the system. TRM and Filtered
Back-Projection (FBP) imaging results are both presented to
compare the performance of the TRM and other imaging
techniques in contrast and resolution for MITAT. © 2008
VSP.},
Doi = {10.1163/156939308786390021},
Key = {fds283669}
}
@article{fds283656,
Author = {Liu, Y and Nie, Z and Liu, QH},
Title = {Reducing the number of elements in a linear antenna array by
the matrix pencil method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {56},
Number = {9},
Pages = {2955-2962},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2008},
Month = {September},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2008.928801},
Abstract = {The synthesis of a nonuniform antenna array with as few
elements as possible has considerable practical
applications. This paper introduces a new non-iterative
method for linear array synthesis based on the matrix pencil
method (MPM). The method can synthesize a nonuniform linear
array with a reduced number of elements, and can be also
used to reduce the number of elements for linear arrays
designed by other synthesis techniques. In the proposed
method, the desired radiation pattern is first sampled to
form a discrete pattern data set. Then we organize the
discrete data set in a form of Hankel matrix and perform the
singular value decomposition (SVD) of the matrix. By
discarding the non-principal singular values, we obtain an
optimal lower-rank approximation of the Hankel matrix. The
lower-rank matrix actually corresponds to fewer antenna
elements. The matrix pencil method is then utilized to
reconstruct the excitation and location distributions from
the approximated matrix. Numerical examples show the
effectiveness and advantages of the proposed synthesis
method. © 2008 IEEE.},
Doi = {10.1109/TAP.2008.928801},
Key = {fds283656}
}
@article{fds283657,
Author = {Liu, QF and Yin, WY and Mao, JF and Liu, QH},
Title = {Shielding effectiveness characterization of metallic
enclosures with a thin-sheet panel illuminated by a
arbitrary polarizations high-power EMP},
Journal = {2008 Asia Pacific Symposium on Electromagnetic Compatibility
and 19th International Zurich Symposium on Electromagnetic
Compatibility, Apemc 2008},
Pages = {730-733},
Publisher = {IEEE},
Year = {2008},
Month = {September},
url = {http://dx.doi.org/10.1109/APEMC.2008.4559979},
Abstract = {This paper presents an improved sub-cell model for modeling
thin material in metallic enclosures using the
finite-difference time-domain (FDTD) method. The enhanced
thin material sub-cell algorithm proposed can model thin
magnetic material sheets including their losses. Our FDTD
results are compared with the shielding effectiveness
obtained by transmission line method, with good agreements
achieved. Therefore, the enhanced sub-cell algorithm is
further used to predict shielding effectivenesses of some
metallic enclosures with thin material sheet on the
apertures in the presence of an arbitrary polarization
high-power ultra-wideband electromagnetic
pulse.},
Doi = {10.1109/APEMC.2008.4559979},
Key = {fds283657}
}
@article{fds283658,
Author = {Wang, J and Liu, QF and Yin, WY and Mao, JF and Liu,
QH},
Title = {A new conformal technique for FDTD (2, 4)scheme for modeling
perfectly conducting composites},
Journal = {2008 Asia Pacific Symposium on Electromagnetic Compatibility
and 19th International Zurich Symposium on Electromagnetic
Compatibility, Apemc 2008},
Pages = {64-67},
Publisher = {IEEE},
Year = {2008},
Month = {September},
url = {http://dx.doi.org/10.1109/APEMC.2008.4559812},
Abstract = {A modified conformal technique for fourth-order
finite-difference time-domain (FDTD (2, 4)) is proposed.
This conformal scheme has higher-order accuracy than that of
conventional FDTD and FDTD (2, 4) methods, which are caused
by staircasing errors when modeling curved metallic objects.
Two integration loops of Faraday's law for the updating of
magnetic field components are introduced here. Numerical
examples show that the proposed scheme can achieves higher
accuracy and low dispersion errors, compared with the
low-order conformal method and the conventional staircased
FDTD method.},
Doi = {10.1109/APEMC.2008.4559812},
Key = {fds283658}
}
@article{fds283667,
Author = {Zeng, YQ and Liu, QH and Zhao, G},
Title = {Response to comment on "multidomain pseudospectral
time-domain (PSTD) method for acoustic waves in lossy
media"},
Journal = {Journal of Computational Acoustics},
Volume = {16},
Number = {3},
Pages = {469-470},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {2008},
Month = {September},
ISSN = {0218-396X},
url = {http://dx.doi.org/10.1142/S0218396X08003713},
Doi = {10.1142/S0218396X08003713},
Key = {fds283667}
}
@article{fds283666,
Author = {Chen, GP and Yu, WB and Zhao, ZQ and Nie, ZP and Liu,
QH},
Title = {The design of ElectroMagnetically Induced Thermo-Acoustic
system and the signal processing using wavelet analysis with
a soft thresholding method},
Journal = {Tien Tzu Hsueh Pao/Acta Electronica Sinica},
Volume = {36},
Number = {6},
Pages = {1130-1134},
Year = {2008},
Month = {June},
ISSN = {0372-2112},
Abstract = {This paper presents an experimental system of
ElectroMagnetically Induced Thermo-Acoustic (EMITA).
Focusing on the signal extraction of EMITA, several
treatments are adopted to improve the compatibility of the
system under high power electromagnetic pulses. To improve
the transition of the microwave energy to the biologic
tissue, the cross section of the vessel front to the
microwave is designed as bevel; to decrease the
electromagnetic impose of ultrasound transducer due to the
microwave pulse, the coupling liquid is used after careful
study. In order to extract the EMITA signals from low
signal-to-noise ratio (SNR) background, wavelet analysis
with soft thresholding is used to filter the strong noise.
Experimental results indicate the effectiveness of the
wavelet analysis in the extraction of EMITA
signals.},
Key = {fds283666}
}
@article{fds283665,
Author = {Huang, Y and Yin, WY and Liu, QH},
Title = {Performance prediction of carbon nanotube bundle dipole
antennas},
Journal = {Ieee Transactions on Nanotechnology},
Volume = {7},
Number = {3},
Pages = {331-337},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2008},
Month = {May},
ISSN = {1536-125X},
url = {http://dx.doi.org/10.1109/TNANO.2007.915017},
Abstract = {A theoretical investigation is carried out for predicting
radiation characteristics of single-walled carbon nanotube
(SWCNT) bundle dipole antennas based on the distributed
circuit parameters and the model of an SWCNT, where the
cross section of bundles can be in a circular and a
rectangular geometry, respectively. The current
distributions in such novel antennas are predicted to
investigate the effects of bundle cross-sectional size, tube
diameter, tube length, and operating frequency. Furthermore,
comparative studies are performed to show the geometry-and
frequency-dependent radiation resistance, far-field pattern,
and radiation efficiency of some typical bundle dipole
antennas, which are numerically confirmed to outperform an
SWCNT antenna by 30-40 dB in radiation efficiency. © 2008
IEEE.},
Doi = {10.1109/TNANO.2007.915017},
Key = {fds283665}
}
@booklet{Xiao08,
Author = {Xiao, T and Liu, QH},
Title = {A 3-D enlarged cell technique (ECT) for the conformal FDTD
method},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {56},
Number = {3},
Pages = {765-773},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2008},
Month = {March},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2008.916876},
Abstract = {In this paper, we present an enlarged cell technique (ECT)
to avoid the time step reduction encountered in the
conformal finite-difference time-domain (CFDTD) method due
to small irregular cells truncated by metallic boundaries.
We focus our efforts on the discussion of the accuracy and
stability of the ECT and its comparison with other conformal
methods, especially the one called the uniformly stable
conformal (USC) method. We also provide a simplified ECT,
which is much easier to implement. In the ECT, a stability
criterion is first constructed to identify instable
irregular cells, i.e., those having so small an area to
cause instability. Those instable cells are then enlarged
into their adjacent cells to obtain a large, stable area.
Careful treatment is performed on the communication between
the intruding and intruded cells in terms of electromotive
force by keeping the total electromotive force conservative.
This technique is verified by several 3-D numerical
experiments. Results show that the ECT is second-order
accurate and numerically stable at the regular Courant time
step limit. © 2008 IEEE.},
Doi = {10.1109/TAP.2008.916876},
Key = {Xiao08}
}
@article{fds283655,
Author = {Cheng, C and Lee, JH and Massoud, HZ and Liu, QH},
Title = {3-D self-consistent Schrödinger-Poisson solver: The
spectral element method},
Journal = {Journal of Computational Electronics},
Volume = {7},
Number = {3},
Pages = {337-341},
Publisher = {Springer Nature},
Year = {2008},
Month = {February},
ISSN = {1569-8025},
url = {http://dx.doi.org/10.1007/s10825-008-0204-8},
Abstract = {In this paper, we developed an efficient three-dimensional
(3-D) nanoelectronic device simulator based on a
self-consistent Schrödinger-Poisson solver to simulate
quantum transport. An efficient and fast algorithm, the
spectral element method (SEM), is developed in this
simulator to achieve spectral accuracy where the error
decreases exponentially with the increase in the sampling
density and the order of the polynomial basis functions,
thus significantly reducing the CPU time and memory usage.
Perfectly matched layer (PML) boundary method, as an
alternative to the open-boundary conditions in NEGF, is
applied in this solver to simplify the numerical
implementation. The validity of the Schrödinger and Poisson
solvers are illustrated by a multiple-terminal device and a
spherical charge example, respectively. The utility of the
self-consistent Schrödinger-Poisson solver is illustrated
by a nanotube example. © Springer Science+Business Media
LLC 2008.},
Doi = {10.1007/s10825-008-0204-8},
Key = {fds283655}
}
@article{fds283664,
Author = {Wei, BJ and Song, DG and Liu, QH},
Title = {Hybrid DTA-BCGS algorithm for simulating electromagnetic
scattering of 3-D inhomogeneous objects in horizontally
stratified medium},
Journal = {Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of
China University of Petroleum (Edition of Natural
Science)},
Volume = {32},
Number = {1},
Pages = {156-161},
Year = {2008},
Month = {February},
ISSN = {1673-5005},
Abstract = {A hybrid implementation of a novel scattering
approximation-diagonal tensor approximation (DTA) with the
stabilized biconjugate-gradient fast Fourier transform
(BCGS-FFT) algorithm for integral equations was developed to
improve the efficiency for accurate simulating
electromagnetic scattering of 3-D inhomogeneous objects in
horizontally stratified medium. Two kinds of approximation
were obtained, which can be accelerated by the fast Fourier
transform technique. The DTA solution is used as both the
initial estimate and the pre-conditioner in the BCGS-FFT
algorithm in order to solve the scattered electromagnetic
fields accurately with fewer iterations than conventional
BCGS-FFT. The accuracy and convergence of DTA, the hybrid
DTA-BCGS and BCGS-FFT were compared with several numerical
examples. The numerical results show that the second kind of
improved diagonal tensor approximation (DTA2) is greatly
superior in the accuracy and that the hybrid DTA-BCGS
algorithm can produce results as accurate as the
conventional BCGS-FFT but with fewer iterations.},
Key = {fds283664}
}
@article{fds283654,
Author = {Wei, B and Zhang, G and Liu, Q},
Title = {Recursive algorithm and accurate computation of dyadic
Green's functions for stratified uniaxial anisotropic
media},
Journal = {Science in China Series F: Information Sciences},
Volume = {51},
Number = {1},
Pages = {63-80},
Publisher = {Springer Nature America, Inc},
Year = {2008},
Month = {January},
ISSN = {1009-2757},
url = {http://dx.doi.org/10.1007/s11432-007-0069-7},
Abstract = {A recursive algorithm is adopted for the computation of
dyadic Green's functions in three-dimensional stratified
uniaxial anisotropic media with arbitrary number of layers.
Three linear equation groups for computing the coefficients
of the Sommerfeld integrals are obtained according to the
continuity condition of electric and magnetic fields across
the interface between different layers, which are in
correspondence with the TM wave produced by a vertical unit
electric dipole and the TE or TM wave produced by a
horizontal unit electric dipole, respectively. All the
linear equation groups can be solved via the recursive
algorithm. The dyadic Green's functions with source point
and field point being in any layer can be conveniently
obtained by merely changing the position of the elements
within the source term of the linear equation groups. The
problem of singularities occurring in the Sommerfeld
integrals is efficiently solved by deforming the integration
path in the complex plane. The expression of the dyadic
Green's functions provided by this paper is terse in form
and is easy to be programmed, and it does not overflow.
Theoretical analysis and numerical examples show the
accuracy and effectivity of the algorithm. © 2008 Science
in China Press.},
Doi = {10.1007/s11432-007-0069-7},
Key = {fds283654}
}
@booklet{Lim08,
Author = {Lim, KH and Lee, JH and Liu, QH},
Title = {Thermoacoustic tomography forward modeling with the spectral
element method},
Journal = {Medical Physics},
Volume = {35},
Number = {1},
Pages = {4-12},
Year = {2008},
Month = {January},
ISSN = {0094-2405},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18293555},
Abstract = {A thermoacoustic tomography (TAT) forward solver based on
the spectral element method (SEM) with perfectly matched
layer absorbing boundary condition has been developed. The
TAT forward solver is intended to model acoustically
inhomogeneous media with high accuracy in the frequency
domain. The high-order basis functions used in the SEM are
Gauss-Lobatto-Legendre (GLL) polynomials. Due to the
orthogonality of the GLL basis functions and GLL quadrature
integration, the mass matrix is diagonal and the stiffness
matrix is sparse. Thus, the proposed method greatly reduces
the memory requirement and computational time in comparison
with the conventional finite element method (FEM). Numerical
results show that the high-order SEM is able to achieve the
same accuracy as the FEM but with a much smaller number of
unknowns. Therefore, the TAT forward solver based on SEM is
able to simulate a large-scale and realistic TAT problem.
(c) 2008 American Association of Physicists in
Medicine.},
Doi = {10.1118/1.2805478},
Key = {Lim08}
}
@article{fds283668,
Author = {Huang, HX and Li, Y and Liu, QS and Liu, QH and Chen, YD and Wan, L and Zhuang, H and Zhao, KW},
Title = {Effects of Chinese herbs of tonifying kidney on bone mineral
density and contents of insulin-like growth factor-1 and
tumor necrosis factor-alpha in osteoporotic
rats},
Journal = {Journal of Clinical Rehabilitative Tissue Engineering
Research},
Volume = {12},
Number = {37},
Pages = {7219-7222},
Year = {2008},
ISSN = {1673-8225},
Abstract = {Background: Studies have shown that insulin growth factor
and tumor necrosis factor α (TNF- α) can regulate
osteoblast and osteoclast. Objective: To explore the effect
of Chinese medicine prescription of tonifying kidney on bone
mineral density, insulin-like growth factor-1 (IGF-1) and
TNF- α in osteoporotic rats. Design, time and setting:
Randomized controlled animal trial was performed at Animal
Center and Orthopedic Hospital of Guangzhou University of
Chinese Medicine from September 2006 to March 2007.
Materials: Sixty-eight SPF 6-month-old healthy female SD
rats weighing 260-280 g were randomly divided into normal
group (n=22) and model group (n=46). Three months after
surgery, 10 rats from each group were selected to confirm
modeling. The other rats in ovariectomized group were
randomly divided into 3 groups (n=12): ovariectomized group
(OVX), estrogen group, and traditional Chinese herb group.
The other 12 rats in the normal group served as control
group. The traditional Chinese herb consisted of Yinyanghuo,
Buguzhi, Danshen, Huangqi and other six kinds of herbs
containing crude drug of 1 430 g/L, prepared by
Manufacturing Laboratory of Orthopaedic Hospital of
Guangzhou University of Chinese Medicine. Methods: The rats
of traditional Chinese herb group were intragastrically
administrated with herbs (4.8 g/kg), once a day. The rats of
estrogen group were intragastrically infused nilestriol (1
mg/ kg), once a week. The others were given distilled water
(10 mL/kg), once a day. The administration lasted for 3
months. Main outcome measures: Total body, lumbar vertebral
and hip bone mineral density (BMD) was measured by dual
energy X-ray absorptiometry, and the content of IGF-1,
estrogen and TNF- α in blood serum were detected with
radioimmunoassay. Results: Sixty-four rats were included in
the final analysis. The BMD of OVX group was significantly
decreased compared with the control group (P < 0.05).
After treatment, the BMD of the total body and lumbar
vertebrae in the rats of Chinese herb and estrogen groups
were significant higher than OVX group (P < 0.05), but
there were no significant differences between Chinese herb
and estrogen groups (P > 0.05). Compared with OVX group,
Chinese herbs markedly reduced TNF- α levels, and increased
IGF-1 and estrogen content (P < 0.05), but there were no
significant differences compared with estrogen group.
Estrogen content in estrogen group was significantly lower
than the other groups. Conclusion: Chinese medicine
prescription of tonifying kidney plays estrogen-like role in
treating osteoporosis, but has different influence on IGF-1
from estrogen.},
Key = {fds283668}
}
@article{fds283778,
Author = {Ye, G and Lim, KH and Jr, RTG and Ybarra, GA and Joines, WT and Liu,
QH},
Title = {3D EIT for breast cancer imaging: System, measurements, and
reconstruction},
Journal = {Microwave and Optical Technology Letters},
Volume = {50},
Number = {12},
Pages = {3261-3271},
Publisher = {WILEY},
Year = {2008},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.23932},
Abstract = {Electrical impedance tomography (EIT) is a developing
imaging modality for early detection of breast cancer. In an
EIT system, a low-frequency current is applied sequentially
between different electrode pairs while voltage measurements
are made at other electrodes to arrive at the electrical
impedance values. The set of impedance measurement data is
then computed to produce a 3D electrical conductivity map of
the volume to be imaged. In this work, the design,
measurements, and inversion of a full 3D EIT system are
discussed. Experimentally determined EIT images of phantom
objects are presented. © 2008 Wiley Periodicals,
Inc.},
Doi = {10.1002/mop.23932},
Key = {fds283778}
}
@booklet{Yu08,
Author = {Yu, C and Yuan, M and Stang, J and Bresslour, E and George, RT and Ybarra,
GA and Joines, WT and Liu, QH},
Title = {Active microwave imaging II: 3-D system prototype and image
reconstruction from experimental data},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {56},
Number = {4},
Pages = {991-1000},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2008},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2008.919661},
Abstract = {A 3-D microwave imaging system prototype and an inverse
scattering algorithm are developed to demonstrate the
feasibility of 3-D microwave imaging for medical
applications such as breast cancer detection with measured
data. In this experimental prototype, the transmitting and
receiving antennas are placed in a rectangular tub
containing a fluid. The microwave scattering data are
acquired by mechanically scanning a single transmit antenna
and a single receive antenna, thus avoiding the mutual
coupling that occurs when an array is used. Careful design
and construction of the system has yielded accurate
measurements of scattered fields so that even the weak
scattered signals at S21= -90dB (or 30 dB below the
background fields) can be measured accurately. Measurements
are performed in the frequency domain at several discrete
frequencies. The collected 3-D experimental data in fluid
are processed by a 3-D nonlinear inverse scattering
algorithm to unravel the complicated multiple scattering
effects and produce high-resolution 3-D digital images of
the dielectric constant and conductivity of the imaging
domain. Dielectric objects as small as 5 mm in size have
been imaged effectively at 1.74 GHz. © 2006
IEEE.},
Doi = {10.1109/TMTT.2008.919661},
Key = {Yu08}
}
@article{fds283768,
Author = {Liu, J and Lin, Y and Lee, JH and Simsek, E and Liu,
QH},
Title = {Application of the hybrid spectral integral method with
spectral element method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {5611},
Publisher = {IEEE},
Year = {2007},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2007.4396821},
Doi = {10.1109/APS.2007.4396821},
Key = {fds283768}
}
@article{fds283841,
Author = {Lee, JH and Liu, QH},
Title = {Nanophotonic applications of the discontinuous spectral
element time-domain (DG-SETD) method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {4356},
Publisher = {IEEE},
Year = {2007},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2007.4396506},
Doi = {10.1109/APS.2007.4396506},
Key = {fds283841}
}
@article{fds283842,
Author = {Chai, M and Liu, QH},
Title = {A hybrid PSTD-FDTD method for indoor wireless communication
systems},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {5371-5374},
Publisher = {IEEE},
Year = {2007},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2007.4396761},
Doi = {10.1109/APS.2007.4396761},
Key = {fds283842}
}
@article{fds283653,
Author = {Cheng, C and Lee, J-H and Lim, KH and Massoud, HZ and Liu,
QH},
Title = {3-D Quantum Transport Solver Based on the Perfectly Matched
Layer and Spectral Element Methods for the Simulation of
Semiconductor Nanodevices.},
Journal = {Journal of Computational Physics},
Volume = {227},
Number = {1},
Pages = {455-471},
Year = {2007},
Month = {November},
ISSN = {0021-9991},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18037971},
Abstract = {A 3-D quantum transport solver based on the spectral element
method (SEM) and perfectly matched layer (PML) is introduced
to solve the 3-D Schrödinger equation with a tensor
effective mass. In this solver, the influence of the
environment is replaced with the artificial PML open
boundary extended beyond the contact regions of the device.
These contact regions are treated as waveguides with known
incident waves from waveguide mode solutions. As the
transmitted wave function is treated as a total wave, there
is no need to decompose it into waveguide modes, thus
significantly simplifying the problem in comparison with
conventional open boundary conditions. The spectral element
method leads to an exponentially improving accuracy with the
increase in the polynomial order and sampling points. The
PML region can be designed such that less than -100 dB
outgoing waves are reflected by this artificial material.
The computational efficiency of the SEM solver is
demonstrated by comparing the numerical and analytical
results from waveguide and plane-wave examples, and its
utility is illustrated by multiple-terminal devices and
semiconductor nanotube devices.},
Doi = {10.1016/j.jcp.2007.07.028},
Key = {fds283653}
}
@article{fds283850,
Author = {Wartenberg, SA and Zhao, G and Liu, QH},
Title = {Electrical and thermal cosimulation of GaAs
interconnects},
Journal = {Ieee Transactions on Advanced Packaging},
Volume = {30},
Number = {4},
Pages = {758-762},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2007},
Month = {November},
ISSN = {1521-3323},
url = {http://dx.doi.org/10.1109/TADVP.2007.901651},
Abstract = {It is well known that the poor thermal conductivity of GaAs
adversely affects the electrical performance of GaAs
circuits. Although they interact, the electrical and thermal
circuits are simulated using separate software simulation
packages. If the circuits are cosimulated on the same
package, then the electrical and thermal circuits can
interactively determine accurate information for the
temperature-dependent variables of the electrical circuit.
This paper demonstrates a method of electrical and thermal
cosimulation of GaAs interconnects. To illustrate, the
method is implemented on a meander line deposited on a GaAs
epitaxial substrate. Each horizontal and vertical section of
the meander is viewed as an individual heat source cell. An
iterative procedure solves for the temperature of each cell
and predicts the dc resistance of the line. Using a
first-order thermal circuit, simulation shows good agreement
with experimental data. © 2006 IEEE.},
Doi = {10.1109/TADVP.2007.901651},
Key = {fds283850}
}
@booklet{Song07,
Author = {Song, J and Liu, QH and Johnson, GA and Badea, CT},
Title = {Sparseness prior based iterative image reconstruction for
retrospectively gated cardiac micro-CT.},
Journal = {Medical Physics},
Volume = {34},
Number = {11},
Pages = {4476-4483},
Year = {2007},
Month = {November},
ISSN = {0094-2405},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18072512},
Abstract = {Recent advances in murine cardiac studies with
three-dimensional (3D) cone beam micro-CT used a
retrospective gating technique. However, this sampling
technique results in a limited number of projections with an
irregular angular distribution due to the temporal
resolution requirements and radiation dose restrictions.
Both angular irregularity and undersampling complicate the
reconstruction process, since they cause significant
streaking artifacts. This work provides an iterative
reconstruction solution to address this particular
challenge. A sparseness prior regularized weighted l2 norm
optimization is proposed to mitigate streaking artifacts
based on the fact that most medical images are compressible.
Total variation is implemented in this work as the
regularizer for its simplicity. Comparison studies are
conducted on a 3D cardiac mouse phantom generated with
experimental data. After optimization, the method is applied
to in vivo cardiac micro-CT data.},
Doi = {10.1118/1.2795830},
Key = {Song07}
}
@article{fds283770,
Author = {Liu, J and Liu, QH},
Title = {A novel radiation boundary condition for finite-element
method},
Journal = {Microwave and Optical Technology Letters},
Volume = {49},
Number = {8},
Pages = {1995-2002},
Publisher = {WILEY},
Year = {2007},
Month = {August},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.22608},
Abstract = {This paper presents a novel radiation boundary condition
(RBC) with the spectral integral method (SIM) to truncate
the computational domain in the finite-element method (FEM).
Because of the spectral accuracy of the SIM, the sampling
density on the radiation boundary requires less than four
points per wavelength to achieve a high accuracy (1%). As a
result, the introduction of the SIM as an RBC actually can
decrease the total number of unknowns in the system
equation. Numerical results illustrate the usefulness of
this novel RBC for both homogeneous and inhomogeneous
objects. © 2007 Wiley Periodicals, Inc.},
Doi = {10.1002/mop.22608},
Key = {fds283770}
}
@article{fds283848,
Author = {Wei, BJ and Liu, QH},
Title = {Contrast source inversion algorithm for reconstructing 3-D
objects in stratified medium},
Journal = {Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of
China University of Petroleum (Edition of Natural
Science)},
Volume = {31},
Number = {4},
Pages = {38-45},
Year = {2007},
Month = {August},
ISSN = {1673-5005},
Abstract = {Contrast source inversion (CSI) algorithm recasts the
inversion problem as a minimization of a cost functional,
thus an iterative sequence is formed to reconstruct the
contrast sources and contrasts. A 3-D CSI algorithm was
developed to reconstruct 3-D objects in stratified medium.
It is an extension of 2-D CSI algorithm. As there is no need
for the forward solver and a manual selection of
regularization parameter in the algorithm, the inversion
process is more stable. The fast Fourier transform
technology is adopted to calculate the dyadic Green's
operator and its adjoint operator during each iteration of
CSI, which ensures the high efficiency of the algorithm in
stratified medium. The inversion results for some
complicated models obtained from the CSI algorithm show that
the algorithm is very efficient in reconstructing arbitrary
3-D inhomogeneous objects in a stratified
medium.},
Key = {fds283848}
}
@article{fds283847,
Author = {Wei, BJ and Liu, QH},
Title = {Through-the-wall detection: 2-D tomographic simulation in
stratified medium},
Journal = {Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of
China University of Petroleum (Edition of Natural
Science)},
Volume = {31},
Number = {3},
Pages = {49-53+58},
Year = {2007},
Month = {June},
ISSN = {1673-5005},
Abstract = {A 2-D nonlinear inverse scattering technique based on
contrast source inversion (CSI) algorithm was developed for
the tomography of 2-D objects in stratified medium, and the
through-the-wall detection was simulated via the technique.
The effectiveness of the CSI algorithm and the feasibility
of through-the-wall detection were proven by the inversion
results of some complicated models. Numerical simulation
results show that the location, shape and electric
parameters of the object may still be reconstructed
accurately via inverting multi-frequency data under limited
view of measurement.},
Key = {fds283847}
}
@article{fds283652,
Author = {Cheng, C and Lee, J and Lim, KH and Massoud, HZ and Liu,
QH},
Title = {Solution of the 3-D schrödinger equation with tensor
effective mass based on perfectly matched layer and spectral
element methods},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {6468},
Publisher = {SPIE},
Year = {2007},
Month = {May},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.696730},
Abstract = {A simple and systematic algorithm based on the perfectly
matched layer (PML) method and spectral element method (SEM)
is introduced to solve the 3-D Schrödinger equation with
tensor effective mass. This algorithm extends the lead
regions of a device into artificial PML media, where a
modified Schrödinger equation is satisfied. The interface
between the physical and PML media has zero reflection
coefficients, thus waves attenuating rapidly into the PML
region before transmitting to the contact boundary. This
algorithm provides a highly effective open boundary
condition in solving quantum transport problems. The
additional PML region can be designed such that less than
-100 dB incoming waves are reflected by this artificial
material with the implementation of the spectral element
method. Consequently, the solution of the Schrödinger
equation and thus the current in the original device region
do not deviate from the correct solution. In this algorithm,
the transmitted wave function is treated as a total wave
instead of being decomposed into waveguide modes, therefore,
it significantly simplifies the problem in comparison with
conventional open boundary conditions. The implementation of
the tensor effective mass provides an excellent tool to
study strain effects along any arbitrary orientation. Within
this PML implementation, the spectral element method has
been applied to achieve an error that exponentially
decreases with the increase of the polynomial order and
sampling points. This accuracy has been demonstrated by
comparing the numerical and analytical results from
waveguide examples, and its utility is illustrated by
multiple-port devices and nanotube devices.},
Doi = {10.1117/12.696730},
Key = {fds283652}
}
@article{fds283844,
Author = {Wei, B and Şimşek, E and Yu, C and Liu, QH},
Title = {Three-dimensional electromagnetic nonlinear inversion in
layered media by a hybrid diagonal tensor approximation:
Stabilized biconjugate gradient fast Fourier transform
method},
Journal = {Waves in Random and Complex Media},
Volume = {17},
Number = {2},
Pages = {129-147},
Publisher = {Informa UK Limited},
Year = {2007},
Month = {May},
ISSN = {1745-5030},
url = {http://dx.doi.org/10.1080/17455030601016117},
Abstract = {This paper presents an efficient three-dimensional nonlinear
electromagnetic inversion method in a multilayered medium
for radar applications where the object size is comparable
to the wavelength. In the first step of this two-step
inversion algorithm, the diagonal tensor approximation is
used in the Born iterative method. The solution of this
approximate inversion is used as an initial guess for the
second step in which further inversion is carried out using
a distorted Born iterative method. Since the aim of the
second step is to improve the accuracy of the inversion, a
full-wave solver, the stabilized biconjugate-gradient fast
Fourier transform algorithm, is used for forward modelling.
The conjugate-gradient method is applied at each inversion
iteration to minimize the functional cost. The usage of an
iterative solver based on the FFT algorithm and the
developed recursive matrix method combined with an
interpolation technique to evaluate the layered medium
Green's functions rapidly, makes this method highly
efficient. An inversion problem with 32 768 complex unknowns
can be solved with 1% relative error by using a simple
personal computer. Several numerical experiments for
arbitrarily located source and receiver arrays are presented
to show the high efficiency and accuracy of the proposed
method.},
Doi = {10.1080/17455030601016117},
Key = {fds283844}
}
@article{fds283845,
Author = {Chai, M and Xiao, T and Zhao, G and Liu, QH},
Title = {A hybrid PSTD/ADI-CFDTD method for mixed-scale
electromagnetic problems},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {55},
Number = {5},
Pages = {1398-1406},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2007},
Month = {May},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2007.895630},
Abstract = {We propose a hybrid technique combining the pseudospectral
time-domain (PSTD) method with the alternating-direction
implicit conformal finite-difference time-domain (ADI-CFDTD)
method to solve 3-D mixed-scale problems in computational
electromagnetics. A mixed-scale problem contains both
electrically large and relatively homogeneous regions and
electrically small fine details, thus poses a significant
computational challenge to any single computational method
if it is utilized alone. In particular, the ADI-CFDTD method
is an unconditionally stable time-domain method with
second-order spatial accuracy, and allows the time step to
be increased beyond the Courant-Friedrichs-Levy limit; it is
suitable for electrically small problem (structure details
much smaller than a wavelength) but is inefficient and
suffers from large numerical errors for electrically
large-scale regions. The PSTD method, on the other hand, is
accurate and efficient for regions with large, relatively
homogeneous materials, but loses its efficiency for
electrically small structures. The hybrid PSTD/ ADI-CFDTD
method overcomes these disadvantages and is potentially more
useful than the individual solvers. The implementation
details and numerical accuracy of this hybrid method are
examined. Numerical examples demonstrate the advantages of
the hybrid PSTD/ADI-CFDTD method. © 2007
IEEE.},
Doi = {10.1109/TAP.2007.895630},
Key = {fds283845}
}
@article{fds283846,
Author = {Lee, JH and Liu, QH},
Title = {A 3-D spectral-element time-domain method for
electromagnetic simulation},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {55},
Number = {5},
Pages = {983-991},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2007},
Month = {May},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2007.895398},
Abstract = {A spectral-element time-domain (SETD) method is proposed to
solve 3-D transient electromagnetic problems based on
Gauss-Lobatto-Legendre polynomials. It has the advantages of
spectral accuracy and block-diagonal mass matrix. With the
inexpensive inversion of the block-diagonal mass matrix, the
proposed method requires only a trivial sparse matrix-vector
product at each time step, thus significantly reducing CPU
time and memory requirement. Galerkin's method is used for
spatial discretization, and a fourth-order Runge-Kutta
scheme is employed for the time integration. The perfectly
matched layer (PML) is employed to truncate the boundary in
unbounded problems. The pseudospectral time-domain method is
used to simplify the treatment of the PML inside the
proposed SETD method. Numerical examples are shown to verify
the efficiency and the spectral accuracy with the order of
basis functions. © 2007 IEEE.},
Doi = {10.1109/TMTT.2007.895398},
Key = {fds283846}
}
@article{fds283843,
Author = {Wei, BJ and Liu Q H and QH},
Title = {Weak-form BCGS-FFT algorithm for volume integral equations
in stratified medium},
Journal = {Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of
China University of Petroleum (Edition of Natural
Science)},
Volume = {31},
Number = {1},
Pages = {49-55},
Year = {2007},
Month = {February},
ISSN = {1673-5005},
Abstract = {The volume integral equations in stratified medium were
accurately calculated by weak-form stabilized
biconjugate-gradient fast Fourier transform (BCGS-FFT)
algorithm. The dyadic Green's functions in stratified medium
were calculated by recursive matrix method, which can be
easily combined with the volume integral equations. The
rooftop functions were chosen as basis function and testing
function to get the weak-form discretization of the volume
integral equations, thus the singularity can be
circumvented. The discrete form of the volume integral
equations was solved via the stabilized biconjugate-gradient
iteration method, so that the distribution of the electric
field within the inhomogeneous objects can be obtained. It
is assumed that the inhomogeneous objects are only in one
layer of the stratified medium, so that the product between
the dyadic Green's function and the contrast source within
the volume integral equations can be expressed in the form
of convolution or correlation, which can be accelerated by
adopting the fast Fourier transform in x,y and z directions
during each iteration of BCGS. Numerical examples show the
accuracy and efficiency of the algorithm.},
Key = {fds283843}
}
@article{070910448693,
Author = {Wei, B and Ŝimŝek, E and Liu, QH},
Title = {Improved diagonal tensor approximation (DTA) and hybrid
DTA/BCGS-FFT method for accurate simulation of 3D
inhomogeneous objects in layered media},
Journal = {Waves in Random and Complex Media},
Volume = {17},
Number = {1},
Pages = {55-66},
Publisher = {Informa UK Limited},
Year = {2007},
Month = {February},
ISSN = {1745-5030},
url = {http://dx.doi.org/10.1080/17455030600924949},
Keywords = {Approximation theory;Conjugate gradient method;Fast Fourier
transforms;Green's function;Tensors;},
Abstract = {This paper presents an improved diagonal tensor
approximation (DTA) and its hybridization with the
stabilized biconjugate-gradient fast Fourier transform
(BCGS-FFT) algorithm to solve a volume integral equation for
three-dimensional (3D) objects in layered media. The
improvement in DTA is obtained for lossy media through a
higher-order approximation. The interaction between the
dyadic Green's function and the contrast source is
efficiently evaluated by the (FFT) algorithm through the
convolution and correlation theorems. For the hybrid
implementation, the DTA solution is used as an initial
estimate and a preconditioner in the BCGS-FFT algorithm in
order to solve the forwards modelling problem accurately
with fewer iterations than the conventional BCGS-FFT
algorithm. The accuracy and convergence of the DTA, BCGS-FFT
and hybrid DTA/BCGS-FFT methods are compared extensively
with several numerical examples. Numerical results show that
(a) the improved DTA formulation enhances the accuracy and
(b) the DTA/BCGS-FFT method can produce results as accurate
as the conventional BCGS-FFT but with fewer iterations if
the contrast is moderate. For very high contrasts, the
hybrid method does not seem to improve further on the
BCGS-FFT iteration convergence.},
Doi = {10.1080/17455030600924949},
Key = {070910448693}
}
@article{fds283849,
Author = {Wei, BJ and Liu, QH},
Title = {Fast algorithm for simulating 3-D electromagnetic inverse
scattering in horizontally stratified medium via
DTA},
Journal = {Acta Geophysica Sinica},
Volume = {50},
Number = {5},
Pages = {1595-1605},
Year = {2007},
Month = {January},
ISSN = {0001-5733},
Abstract = {Two kinds of approximations called DTA1 and DTA2 for
integral equations are obtained according to different batk
substituting method on the basis of diagonal tensor
approximation (DTA) in order to improve the efficiency for
simulating 3-D electromagnetic scattering and inverse
scattering in horizontally stratified medium. The
approximations can be used as the initial guess and
pre-conditioner in the siabilized biconjugate-gradient fast
Fourier transform (BCGS-FFT) algorithm for computing
integral equations, and hence a hybrid DTA-BCGS algorithm
with higher efficiency is formed. Numerical scattering
examples have shown the high accuracy of DTA2 and the high
efficiency of hybrid DTA-BCGS algorithm, especially of
hybrid DTA2-BCGS. Since DTA2 has a much higher accuracy, it
is combined with distorted Born iterative inversion method
(DBIM) and a fast electromagnetic inverse scattering
technique is formed to reconstruct 3-D inhomogeneous
objects. Numerical inverse scattering examples have
demonstrated the efficiency of the inverse scattering
technique in reconstructing arbitrary 3-D inhomogeneous
objects in horizontally stratified medium.},
Key = {fds283849}
}
@article{fds323120,
Author = {Liu, QH and Yu, C and Stang, J and Yuan, M and Bresslour, E and George, RT and Ybarra, G and Joines, WT},
Title = {Experimental and numerical investigations of a
high-resolution 3D microwave imaging system for breast
cancer detection},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2009-2009},
Publisher = {IEEE},
Year = {2007},
Month = {January},
ISBN = {978-1-4244-0877-1},
Key = {fds323120}
}
@article{fds323121,
Author = {Liu, J and Lin, Y and Lee, J-H and Simsek, E and Liu,
QH},
Title = {Application of the hybrid spectral integral method with
spectral element method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {5120-5120},
Publisher = {IEEE},
Year = {2007},
Month = {January},
ISBN = {978-1-4244-0877-1},
Key = {fds323121}
}
@article{fds323122,
Author = {Chai, M and Liu, QH},
Title = {A hybrid PSTD-FDTD method for indoor wireless communication
systems},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {4892-4895},
Publisher = {IEEE},
Year = {2007},
Month = {January},
ISBN = {978-1-4244-0877-1},
Key = {fds323122}
}
@article{fds323123,
Author = {Lee, J-H and Liu, QH},
Title = {Nanophotonic applications of the discontinuous spectral
element time-domain (DG-SETD) method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {3943-3943},
Publisher = {IEEE},
Year = {2007},
Month = {January},
ISBN = {978-1-4244-0877-1},
Key = {fds323123}
}
@article{fds283776,
Author = {Liu, QH and Yu, C and Stang, J and Yuan, M and Bresslour, E and George, RT and Ybarra, G and Joines, WT},
Title = {Experimental and numerical investigations of a
high-resolution 3D microwave imaging system for breast
cancer detection},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {2192-},
Publisher = {IEEE},
Year = {2007},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2007.4395963},
Doi = {10.1109/APS.2007.4395963},
Key = {fds283776}
}
@article{fds283777,
Author = {Lim, KH and Shi, G and McCarter, K and Jr, RG and Ybarra, G and Joines, WT and Wartenberg, S and Liu, QH},
Title = {2D EIT for biomedical imaging: Design, measurement,
simulation, and image reconstruction},
Journal = {Microwave and Optical Technology Letters},
Volume = {49},
Number = {12},
Pages = {2989-2998},
Publisher = {WILEY},
Year = {2007},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.22938},
Abstract = {A 2D electrical impedance tomography (EIT) system has been
developed at Duke University as an experimental system to
test the forward and inverse algorithms for EIT application.
The forward model is based on the 2nd-order finite element
method (FEM), while the image reconstruction is based on the
distorted Born iterative method (DBIM). The major
contributions of this work are the application of the
higherorder FEM as a forward solver, and the DBIM as an
inverse solver to the integrated EIT system. The forward
model has been validated with the measured data to within
0.5% accuracy. Excellent images have been reconstructed with
these collected EIT data sets. © 2007 Wiley Periodicals,
Inc.},
Doi = {10.1002/mop.22938},
Key = {fds283777}
}
@article{fds283840,
Author = {Borja, AL and Hall, PS and Liu, Q and Iizuka, H},
Title = {Omnidirectional loop antenna with left-handed
loading},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {6},
Pages = {495-498},
Year = {2007},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2007.905016},
Abstract = {This letter presents an omnidirectional horizontally
polarized planar printed loop-antenna using left-handed CL
loading with 50-12 input impedance. The antenna has a one
wavelength circumference and gives an omnidirectional
pattern in the plane of the loop, whilst working in an n = 0
mode. In contrast, a conventional right-handed loop, with
the same dimensions, has a figure of eight pattern in the
plane of the loop. The antenna is compared with other
right-handed periodically loading loop antennas and shown to
have the best efficiency and is much easier to match. Design
details and simulated results are presented. The concept
significantly extends the design degrees of freedom for loon
antennas. © 2007 IEEE.},
Doi = {10.1109/LAWP.2007.905016},
Key = {fds283840}
}
@article{fds304995,
Author = {Song, J and Liu, QH},
Title = {An efficient MR image reconstruction method for arbitrary
K-space trajectories without density compensation.},
Journal = {Conference Proceedings : ... Annual International Conference
of the Ieee Engineering in Medicine and Biology Society.
Ieee Engineering in Medicine and Biology Society. Annual
Conference},
Pages = {3767-3770},
Year = {2006},
Month = {December},
ISSN = {1557-170X},
url = {http://dx.doi.org/10.1109/IEMBS.2006.260151},
Abstract = {Non-Cartesian sampling is widely used for fast magnetic
resonance imaging (MRI). The well known gridding method
usually requires density compensation to adjust the
non-uniform sampling density, which is a major source of
reconstruction error. Minimum-norm least square (MNLS)
reconstruction, on the other hand, does not need density
compensation, but requires intensive computations. In this
paper, a new version of MNLS reconstruction method is
developed using maximum likelihood and is speeded up by
incorporating novel non-uniform fast Fourier transform
(NUFFT) and bi-conjugate gradient fast Fourier transform
(BCG-FFT) techniques. Studies on computer-simulated phantoms
and a physically scanned phantom show improved
reconstruction accuracy and signal-to-noise ratio compared
to gridding method. The method is shown applicable to
arbitrary k-space trajectory. Furthermore, we find that the
method in fact performs un-blurring in the image space as an
equivalent of density compensation in the k-space.
Equalizing MNLS solution with gridding algorithm leads to
new approaches of finding optimal density compensation
functions (DCF). The method has been applied to radially
encoded cardiac imaging on small animals. Reconstructed
dynamic images of an in vivo mouse heart are
shown.},
Doi = {10.1109/IEMBS.2006.260151},
Key = {fds304995}
}
@article{9131066,
Author = {Lim, KH and Liu, QH},
Title = {Thermoacoustic tomography modeling with spectral element
method},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Pages = {1409},
Publisher = {IEEE},
Address = {Albuquerque, NM, USA},
Year = {2006},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2006.1710812},
Keywords = {acoustic tomography;biomedical ultrasonics;finite element
analysis;image reconstruction;medical image
processing;polynomials;thermoacoustics;ultrasonic
imaging;},
Abstract = {Thermoacoustic Tomography (TAT) is a technique that uses
electromagnetic waves to irradiate a tissue and measures the
excited acoustic signals. When irradiated by a short pulse
of EM wave, the tissue is heated up momentarily and acoustic
waves are generated due to the thermoelastic expansion.
Wide-band ultrasonic transducers are employed to acquire the
acoustic signals. The acquired acoustic signals carry
information about the internal thermal and acoustic
properties of the tissue which are to be inverted. Image
reconstruction algorithms are needed to convert ultrasound
signals received at the transducers to full 3D images for
diagnostic application. At present, reconstruction
algorithms for TAT make an assumption that the tissue is
acoustically homogeneous, i.e., the density and speed of
sound are constant throughout the tissue. This simplifying
assumption can cause significant degradation of images. It
is thus desirable to model the effects of tissue
inhomogeneities within the image reconstruction algorithm.
To implement an inversion algorithm for inhomogeneous media,
an accurate and efficient forward solver for TAT is
required. As the frequency of interest in TAT is in the
order of 1 MHz (or a wavelength of about 1.5 mm in soft
tissue), a 3D tissue sample of size 5 3 cm 3 will require a
mesh with more than 30 millions unknowns if the sampling
density is 10 points per wavelength (PPWs) as required by
the finite-element method (FEM). In this work, we propose a
Spectral Element Method (SEM) to solve the TAT forward
problem. With the use of Gauss-Lobatto-Legendre (GLL)
polynomials as basis functions and GLL points as quadrature
integration points, the SEM can achieve the same accuracy as
the FEM with a much lower sampling density, and therefore
the number of unknowns can be greatly reduced. A Perfectly
Matched Layer (PML) is used at the boundary of the
computational domain to absorb outgoing waves. Numerical
results will be shown to validate the SEM, and to
demonstrate the significant advantages of the SEM over the
FEM for large-scale realistic TAT problems. © 2006
IEEE.},
Doi = {10.1109/APS.2006.1710812},
Key = {9131066}
}
@article{fds283769,
Author = {Şimşek, E and Liu, J and Liu, QH},
Title = {A spectral integral method and hybrid SIM/FEM for layered
media},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {54},
Number = {11},
Pages = {3878-3884},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {November},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2006.883647},
Abstract = {This paper first presents a spectral integral method (SIM)
for electromagnetic scattering from homogeneous dielectric
and perfectly electric conducting objects straddling several
layers of a multilayered medium. It then uses this SIM as an
exact radiation boundary condition to truncate the
computational domain in the finite-element method (FEM) to
form a hybrid SIM/FEM, which is applicable to arbitrary
inhomogeneous objects. Due to the high accuracy of the SIM,
the sampling density on the radiation boundary requires less
than five points per wavelength to achieve 1% accuracy. The
efficiency and accuracy of the developed methods have been
demonstrated with several numerical experiments for the TM Z
case. The TE Z case can be obtained by duality. © 2006
IEEE.},
Doi = {10.1109/TMTT.2006.883647},
Key = {fds283769}
}
@article{fds283838,
Author = {Lim, KH and Lee, J-H and Ye, G and Liu, QH},
Title = {An efficient forward solver in electrical impedance
tomography by spectral element method.},
Journal = {Ieee Transactions on Medical Imaging},
Volume = {25},
Number = {8},
Pages = {1044-1051},
Year = {2006},
Month = {August},
ISSN = {0278-0062},
url = {http://www.ncbi.nlm.nih.gov/pubmed/16894997},
Abstract = {In electrical impedance tomography (EIT), a forward solver
capable of predicting the voltages on electrodes for a given
conductivity distribution is essential for reconstruction.
The EIT forward solver is normally based on the conventional
finite element method (FEM). One of the major problems of
three-dimensional (3-D) EIT is its high demand in computing
power and memory since high precision is required for
obtaining a small secondary field which is typical for a
small anomaly. This accuracy requirement is also set by the
level of noise in the real data; although currently the
noise level is still an issue, future EIT systems should
significantly reduce the noise level to be capable of
detecting very small anomalies. To accurately simulate the
forward solution with the FEM, a mesh with large number of
nodes and elements is usually needed. To overcome this
problem, we proposed the spectral element method (SEM) for
EIT forward problem. With the introduction of SEM, a smaller
number of nodes and hence less computational time and memory
are needed to achieve the same or better accuracy in the
forward solution than the FEM. Numerical results demonstrate
the efficiency of the SEM in 3-D EIT simulation.},
Doi = {10.1109/tmi.2006.876143},
Key = {fds283838}
}
@article{fds283836,
Author = {Liu, QM and Wang, LS and Chen, XW and Li, GF},
Title = {Ball nut detection by machine vision},
Journal = {Jilin Daxue Xuebao (Gongxueban)/Journal of Jilin University
(Engineering and Technology Edition)},
Volume = {36},
Number = {4},
Pages = {534-538},
Year = {2006},
Month = {July},
ISSN = {1671-5497},
Abstract = {On the basis of machine vision, a non-contact detection
method was put forward to measure the geometrical size and
shape-position error of the ball nut. The image was
collected by a digital camera A102FCCD, and was input into
computer by a digital interface card IEEE1394. The original
gray level image was changed into the macroscopical drawing
information by pre-processing, threshold selection, image
bivalency, edge detection and contour extraction and
segmentation. The geometrical parameters were calculated and
measured by the aid of the contour extracted from the image
processing and a self-compiled measurement program. The ball
nut thread pitch, the radius of ball center circle, the
sphericity deviation, the cylindricity deviation, and the
ball-way taper were measured and their errors were 0.001,
0.023, 0.010, 0.016 and 0.006 mm respectively. The reason
for error was analyzed, and concluded that the optic error
is the main factor affecting the measurement precision. The
results satisfy the technique requirement of the product.
Theoretical analysis and experimental results show that this
method is feasible and correct.},
Key = {fds283836}
}
@article{fds283837,
Author = {Şimşek, E and Liu Jianguo and J and Liu, QH},
Title = {A spectral integral method (SIM) for layered
media},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {54},
Number = {6},
Pages = {1742-1749},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {June},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2006.875500},
Abstract = {A spectral integral method is presented for electromagnetic
scattering from dielectric and perfectly electric conducting
(PEC) objects with a closed boundary embedded in a layered
medium. Two-dimensional layered medium Green's functions are
computed adaptively by using Gaussian quadratures. The
singular terms in the Green's functions and the non-smooth
terms in their derivatives are handled appropriately to
achieve exponential convergence. Numerical results, compared
with the ones obtained by using other methods, demonstrate
the spectral accuracy and high efficiency of the proposed
method. They also confirm that the spectral integral method
(SIM) is applicable to concave objects. © 2006
IEEE.},
Doi = {10.1109/TAP.2006.875500},
Key = {fds283837}
}
@article{fds283835,
Author = {Chai, M and Xiao, T and Liu, QH},
Title = {Conformal method to eliminate the ADI-FDTD staircasing
errors},
Journal = {Ieee Transactions on Electromagnetic Compatibility},
Volume = {48},
Number = {2},
Pages = {273-281},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {May},
ISSN = {0018-9375},
url = {http://dx.doi.org/10.1109/TEMC.2006.874084},
Abstract = {The alternating-direction-implicit finite-difference
time-domain (ADI-FDTD) method is an unconditionally stable
method and allows the time step to be increased beyond the
Courant-Friedrich-Levy (CFL) stability condition. This
method is potentially very useful for modeling electrically
small but complex features often encountered in
applications. As the regular FDTD method, however, the
spatial discretization in the ADI-FDTD method is only
first-order accurate for discontinuous media; several
researchers have shown that the errors can be very high when
the regular ADI-FDTD method is applied to such discontinuous
media. On the other hand, the conformal FDTD method has
recently emerged as an efficient FDTD method with higher
order accuracy. In this work, a second-order accurate
ADI-FDTD method using the conformal approximation of spatial
derivatives is proposed. This new scheme, called the
ADI-CFDTD method, retains the second-order accuracy in both
temporal and spatial discretizations even for discontinuous
media with metallic structures, and is unconditionally
stable. 2D and 3D examples demonstrate the efficacy of this
method and its application in EMC problems. © 2006
IEEE.},
Doi = {10.1109/TEMC.2006.874084},
Key = {fds283835}
}
@article{fds323124,
Author = {Song, J and Liu, QH and Kim, K and Scott, WR},
Title = {High-resolution 3-D radar imaging through nonuniform fast
Fourier transform (NUFFT)},
Journal = {Communications in Computational Physics},
Volume = {1},
Number = {1},
Pages = {176-191},
Publisher = {Global Science Press},
Year = {2006},
Month = {February},
Key = {fds323124}
}
@article{fds283829,
Author = {Schuhmann, R and Zagorodnov, IA and Weiland, T and Xiao, T and Liu,
QH},
Title = {Comment on "enlarged cells for the conformal FDTD method to
avoid the time step reduction"},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {16},
Number = {1},
Pages = {55-56},
Year = {2006},
Month = {January},
ISSN = {1531-1309},
url = {http://dx.doi.org/10.1109/LMWC.2005.861553},
Doi = {10.1109/LMWC.2005.861553},
Key = {fds283829}
}
@article{fds283830,
Author = {Şimsşek, E and Liu, QH and Wei, B},
Title = {Singularity subtraction for evaluation of Green's functions
for multilayer media},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {54},
Number = {1},
Pages = {216-224},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
Month = {January},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2005.860304},
Abstract = {This paper presents an efficient method to evaluate the two-
and three-dimensional multilayered medium Green's functions
for general electric and magnetic sources. Without finding
any surface poles or steepest descent path, a special
subtraction procedure is applied to each term of the
Sommerfeld integrands to make them rapidly decreasing
functions of kρ. The contributions of the subtracted terms
are calculated analytically. The remaining integrals are
computed adaptively by using Gaussian quadratures. The
accuracy of the method has been confirmed by comparison with
many examples in literature, and the high efficiency has
been verified. © 2006 IEEE.},
Doi = {10.1109/TMTT.2005.860304},
Key = {fds283830}
}
@article{fds283831,
Author = {Sinha, BK and Simsek, E and Liu, QH},
Title = {Elastic wave propagation in deviated wells in anisotropic
formations},
Journal = {Seg Technical Program Expanded Abstracts},
Volume = {25},
Number = {1},
Pages = {324-328},
Publisher = {Society of Exploration Geophysicists},
Year = {2006},
Month = {January},
ISSN = {1052-3812},
url = {http://dx.doi.org/10.1190/1.2370205},
Abstract = {A finite-difference time domain (FDTD) formulation with a
perfectly-matched layer (PML) enables analysis of elastic
wave propagation in a fluid-filled borehole in an
arbitrarily anisotropic formation. The FDTD formulation
yields synthetic waveforms at an array of receivers produced
by a monopole or dipole source placed on the borehole axis.
Synthetic waveforms are then processed by a modified matrix
pencil algorithm to isolate both non-dispersive and
dispersive arrivals in the wavetrain. The tube wave velocity
obtained from the zero-frequency intercept of the Stoneley
dispersion compares very well with the analytical results
for a range of well deviations in both fast and slow
transversely-isotropic (TI) formations. Good agreement is
also obtained between low-frequency asymptotes of borehole
flexural dispersions and the corresponding shear wave
velocities from a numerically exact solution of
Kelvin-Christoffel equations for plane wave velocities in an
arbitrarily anisotropic formation. Numerical results
indicate that the Stoneley dispersion changes by a rather
small amount, whereas dipole flexural dispersions exhibit
larger changes with wellbore deviations. Even though shear
wave splitting occurs in deviated wellbores, shear slowness
anisotropy is less than 2% for well deviations less than 40
degrees from the TI-symmetry axis in certain types of
shales, such as Austin chalk. Anisotropy induced coupling
between the monopole Stoneley and dipole flexural modes is
insignificant in deviated wellbores in the Austin chalk as
well as in fast TI-formations. The influence of an
equivalent heavy-fluid column structure on borehole elastic
waves is described by an equivalent heavy-fluid column
placed concentrically with the borehole axis. The effect of
a heavy-fluid column on the borehole flexural mode is larger
in fast than in slow formations. However, the Stoneley
dispersion at all frequencies is affected by the presence of
the tool structure in both the fast and slow formations. The
present study confirms that the two orthogonal dipole
flexural dispersions are nearly parallel to each other in
slow formations and non-intersecting in fast formations even
in deviated wellbores and in the presence of an equivalent
heavy-fluid column structure. © 2005 Society of Exploration
Geophysicists.},
Doi = {10.1190/1.2370205},
Key = {fds283831}
}
@article{fds283832,
Author = {Song, J and Liu, QH},
Title = {Improving Non-Cartesian MRI Reconstruction through
Discontinuity Subtraction.},
Journal = {International Journal of Biomedical Imaging},
Volume = {2006},
Pages = {87092},
Year = {2006},
Month = {January},
ISSN = {1687-4188},
url = {http://www.ncbi.nlm.nih.gov/pubmed/23165054},
Abstract = {Non-Cartesian sampling is widely used for fast magnetic
resonance imaging (MRI). Accurate and fast image
reconstruction from non-Cartesian k-space data becomes a
challenge and gains a lot of attention. Images provided by
conventional direct reconstruction methods usually bear
ringing, streaking, and other leakage artifacts caused by
discontinuous structures. In this paper, we tackle these
problems by analyzing the principal point spread function
(PSF) of non-Cartesian reconstruction and propose a leakage
reduction reconstruction scheme based on discontinuity
subtraction. Data fidelity in k-space is enforced during
each iteration. Multidimensional nonuniform fast Fourier
transform (NUFFT) algorithms are utilized to simulate the
k-space samples as well as to reconstruct images. The
proposed method is compared to the direct reconstruction
method on computer-simulated phantoms and physical scans.
Non-Cartesian sampling trajectories including 2D spiral, 2D
and 3D radial trajectories are studied. The proposed method
is found useful on reducing artifacts due to high image
discontinuities. It also improves the quality of images
reconstructed from undersampled data.},
Doi = {10.1155/ijbi/2006/87092},
Key = {fds283832}
}
@article{9220083,
Author = {Song, J and Liu, QH},
Title = {An efficient MR image reconstruction method for arbitrary
K-space trajectories without density compensation.},
Journal = {Conference Proceedings : ... Annual International Conference
of the Ieee Engineering in Medicine and Biology Society.
Ieee Engineering in Medicine and Biology Society. Annual
Conference},
Volume = {2006},
Pages = {3767-3770},
Address = {New York, NY, USA},
Year = {2006},
Month = {January},
ISSN = {1557-170X},
url = {http://www.ncbi.nlm.nih.gov/pubmed/17946203},
Keywords = {biomedical MRI;cardiology;fast Fourier transforms;image
reconstruction;image sampling;least squares
approximations;maximum likelihood estimation;medical image
processing;},
Abstract = {Non-Cartesian sampling is widely used for fast magnetic
resonance imaging (MRI). The well known gridding method
usually requires density compensation to adjust the
non-uniform sampling density, which is a major source of
reconstruction error. Minimum-norm least square (MNLS)
reconstruction, on the other hand, does not need density
compensation, but requires intensive computations. In this
paper, a new version of MNLS reconstruction method is
developed using maximum likelihood and is speeded up by
incorporating novel non-uniform fast Fourier transform
(NUFFT) and bi-conjugate gradient fast Fourier transform
(BCG-FFT) techniques. Studies on computer-simulated phantoms
and a physically scanned phantom show improved
reconstruction accuracy and signal-to-noise ratio compared
to gridding method. The method is shown applicable to
arbitrary k-space trajectory. Furthermore, we find that the
method in fact performs un-blurring in the image space as an
equivalent of density compensation in the k-space.
Equalizing MNLS solution with gridding algorithm leads to
new approaches of finding optimal density compensation
functions (DCF). The method has been applied to radially
encoded cardiac imaging on small animals. Reconstructed
dynamic images of an in vivo mouse heart are
shown.},
Doi = {10.1109/iembs.2006.260151},
Key = {9220083}
}
@article{fds283839,
Author = {Sinha, BK and Şimşek, E and Liu, QH},
Title = {Elastic-wave propagation in deviated wells in anisotropic
formations},
Journal = {Geophysics},
Volume = {71},
Number = {6},
Pages = {D191-D202},
Publisher = {Society of Exploration Geophysicists},
Year = {2006},
Month = {January},
ISSN = {0016-8033},
url = {http://dx.doi.org/10.1190/1.2358402},
Abstract = {A finite-difference time-domain (FDTD) formulation with
perfectly matched layer (PML) enables analysis of
elastic-wave propagation in a fluid-filled borehole in an
arbitrarily anisotropic formation. The FDTD formulation
yields synthetic waveforms at an array of receivers produced
by a monopole or dipole source placed on the borehole axis.
Synthetic waveforms are then processed by a modified matrix
pencil algorithm to isolate both nondispersive and
dispersive arrivals in the wavetrain. The processing
algorithm used in this study extracts phase slownesses of
plane waves that agree well with the corresponding phase
slownesses calculated for propagation along an arbitrary
direction in an anisotropic formation. The tube-wave phase
velocity obtained from the zero-frequency intercept of the
Stoneley dispersion compares well with the analytical
results for deviated wellbores in both fast and slow
transversely isotropic (TI) formations. Good agreement is
also obtained between the low-frequency asymptotes of
borehole flexural dispersion and the corresponding
shear-wave velocities from a numerically exact solution of
Kelvin-Christoffel equations for plane-wave velocities in
anisotropic formations. Numerical results indicate that the
Stoneley dispersion changes by a rather small amount,
whereas the dipole flexural dispersions exhibit larger
changes with wellbore deviations. The influence of a sonic
tool structure on borehole elastic-waves can be described by
an equivalent heavy-fluid column placed concentrically with
the borehole axis. The effect of a heavy-fluid column on the
borehole flexural mode is larger in fast than in slow
formations. However, the Stoneley dispersion at low
frequencies is affected by the presence of the tool
structure in both the fast and slow formations. The present
study confirms that the two orthogonal dipole flexural
dispersions are nearly parallel to each other in slow
formations and nonintersecting in fast formations, even in
deviated wellbores and in the presence of a sonic tool
structure described by a heavy-fluid column. © 2006 Society
of Exploration Geophysicists.},
Doi = {10.1190/1.2358402},
Key = {fds283839}
}
@article{fds323125,
Author = {Song, J and Liu, QH},
Title = {An efficient MR image reconstruction method for arbitrary
K-space trajectories without density compensation},
Journal = {2006 28th Annual International Conference of the Ieee
Engineering in Medicine and Biology Society, Vols 1
15},
Pages = {2516-+},
Publisher = {IEEE},
Year = {2006},
Month = {January},
ISBN = {978-1-4244-0032-4},
Key = {fds323125}
}
@article{9198637,
Author = {Joon-Ho Lee and Liu, Q.H.},
Title = {A 3-D spectral element time-domain (SETD) method for
electromagnetic wave problems},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {675 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {electromagnetic waves;Galerkin method;matrix
inversion;Maxwell equations;polynomials;Runge-Kutta
methods;time-domain analysis;wave equations;},
Abstract = {Summary form only given. In this paper, we developed a 3-D
spectral element time-domain (SETD) method to solve the
first-order Maxwell's equations as well as their
second-order wave equations. Galerkin method is used for
spatial discretization, and a fourth-order, four-stage
Runge-Kutta scheme is employed for the time integration.
Because the basis functions are orthogonal and because the
Gauss-Lobato-Legendre (GLL) quadrature is used, the mass
matrix is block-diagonal and thus it can be easily inverted
with little cost. After we obtain the inexpensive inversion
of the mass matrix, it is moved to the right-hand side and
multiplied by stiffness matrices and the resulting matrices
will be still sparse. Finally, only a trivial vector-matrix
product is required in each time step},
Key = {9198637}
}
@article{9175362,
Author = {Joon-Ho Lee and Tian Xiao and Liu, Q.H.},
Title = {A discontinuous spectral element time-domain method for
electromagnetic devices},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {519 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {electromagnetic devices;Galerkin method;matrix
algebra;Maxwell equations;polynomials;Runge-Kutta
methods;time-domain analysis;},
Abstract = {In this paper, we present a discontinuous spectral element
time-domain (SETD) method to solve the first-order
formulation of Maxwell's equations. This method combines the
SETD method with discontinuous Galerkin method (DGM) to
optimize the distribution of nodal points in a multiscale
problem where different regions are best discretized by
different order basis functions. Thus, the basis functions
can be discontinuous across regions. With each element, the
choice of nodal points and quadrature integration points are
based on Gauss-Lobatto-Legendre (GLL) polynomials. Because
the basis functions of the discontinuous SETD are orthogonal
and because the GLL quadrature is used, the mass matrix is
block-diagonal and thus we can avoid the inversion of a
large mass matrix. The time integration is obtained by a
fourth-order, five-stage low storage Runge-Kutta
scheme},
Key = {9175362}
}
@article{9163168,
Author = {Jianguo Liu and Joon-Ho Lee and Simsek, E. and Liu,
Q.H.},
Title = {A hybrid spectral integral method - spectral element method
for electromagnetic wave scattering},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {35 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {acoustic wave scattering;differential equations;electromagnetic
wave scattering;finite element analysis;Fourier
series;integral equations;polynomials;},
Abstract = {In this paper, we propose a hybrid spectral-integral/spectral-element
method (SIM/SEM) to solve three-dimensional electromagnetic
and acoustic wave scattering problems. Lee et. al. have
developed a spectral element method (SEM) to obtain spectral
accuracy with the orders of the basis functions. The SEM can
be considered as a special class of the general finite
element method (FEM), with the choice of nodal points and
quadrature integration points based on Gauss-Lobatto-Legendre
(GLL) polynomials. In the proposed hybrid SIM/SEM technique,
an artificial smooth boundary outside an inhomogeneous and
arbitrarily shaped object is used as a radiation boundary,
where the SIM is applied to solve the integral equation for
the exterior region; the SEM is applied to the interior
region, including the boundary, to solve the differential
equation. The use of Fourier series bases makes it possible
to accurately interpolate between SEM nodal points and SIM
nodal points. The combined SIM/SEM provides spectral
accuracy for both the interior differential equation method
and the boundary integral method. Numerical examples will be
shown to demonstrate this spectral property},
Key = {9163168}
}
@article{9175336,
Author = {Chun Yu and Baojun Wei and Liu, Q.H.},
Title = {Tunnel detection and imaging: 2D and 3D forward and inverse
solvers},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {442 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {buried object detection;electric field integral
equations;electromagnetic wave scattering;fast Fourier
transforms;Green's function methods;inhomogeneous
media;tensors;tunnels;},
Abstract = {In this paper, we developed fast 2D and 3D forward and
inverse solvers for a layered medium based on the volume
electric field integral equations and applied them to tunnel
detection and imaging. These forward and inverse solvers
combine BICGSTAB(L) algorithm, FFT, diagonal tensor
approximation (DTA), and contrast source inversion (CSI)
techniques for the purpose of tunnel detection. The
layered-medium Green's functions are used to formulate 2D
and 3D volume integral equations. For the 3D layered-medium
dyadic Green's function, a compact representation is given
based on scattering superposition of the field in the
spatial domain, in which all components of the dyadic
Green's function are expressed as combinations of a few
basic Sommerfeld integrals and calculated recursively. The
BICGSTAB(L) algorithm is combined with FFT to accelerate the
solution of the integral equations. The diagonal tensor
approximation is investigated in the acceleration of full
nonlinear CSI inverse solver for layered
media},
Key = {9175336}
}
@article{9198638,
Author = {Mei Chai and Tian Xiao and Gang Zhao and Liu,
Q.H.},
Title = {A hybrid PSTD/FDTD method for multiscale
problems},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {676 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {computational electromagnetics;finite difference time-domain
analysis;spectral analysis;},
Abstract = {In this paper, we further extend the hybrid technique, which
is the combination of the pseudospectral time-domain (PSTD)
method with a version of FDTD method, to combine the PSTD
method with two versions of advanced FDTD methods, i.e., the
alternating direction implicit conformal FDTD (ADI-CFDTD)
and CFDTD methods for full 3D problems. Both CFDTD and
ADI-CFDTD methods are second-order accurate in spatial
discretization; the former is ideal for the intermediate
scale where the geometrical feature size is approximately
between 1/20 of a wavelength to about one wavelength, while
the latter is ideal for the fine scale below the
intermediate scale, and the PSTD method is ideal for the
coarse scale above the intermediate scale. Such a hybrid
method is close to being optimal in terms of its accuracy
and efficiency. Numerical results are shown to demonstrate
the effectiveness of this hybrid PSTD/FDTD
method},
Key = {9198638}
}
@article{9187406,
Author = {Kim Hwa Lim and Gang Ye and Liu, Q.H.},
Title = {3D EIT forward and inverse modeling},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {398 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {electric impedance imaging;},
Abstract = {In this work, spectral element method (SEM) instead of FEM
has been used to solve the EIT forward problem. The
electrode contact impedances are accounted for by the
complete electrode model. Numerical results show that the
SEM is capable of achieving better accuracy than the FEM
with the same degree of freedom. Furthermore, the SEM is
able to achieve "spectral accuracy" in which the error
decreases exponentially with the increasing order of basis
functions},
Key = {9187406}
}
@article{9187476,
Author = {Tian Xiao and Junpeng Guo and Liu, Q.H.},
Title = {Nanophotonics application of 3D spectral discontinuous
Galerkin method and enlarged cell technique},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {599 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {computational electromagnetics;dispersive media;Galerkin
method;light propagation;time-domain analysis;},
Abstract = {Computational electromagnetics is finding many applications
in nanophotonics where phenomena of electromagnetic waves
interacting with nanoscale structures are studied. This work
is mainly concerned with optical waves interacting with
nano-metallic objects. One important design objective in
nanophotonics is to determine an optimal structure that can
support surface plasmon waves with minimum propagation loss
along the waveguide direction. In order to perform optimal
design of such nanophotonic devices involving metallic
objects, two time-domain computational electromagnetic
algorithms are adopted, the spectral discontinuous Galerkin
method (DGM) and the enlarged cell technique (ECT). The DGM
has spectral accuracy and is ideal for large structures,
while the ECT, as a further improvement over the conformal
FDTD method, has second-order accuracy and is ideal for
sub-wavelength structures. Using these two methods, one can
accurately and efficiently model electromagnetic waves
propagating in nano-photonic structures with dispersive
media. These methods were used to design several interesting
surface plasmon waveguides with small attenuation. Results
are shown to demonstrate the effectiveness of the
approach},
Key = {9187476}
}
@article{9198639,
Author = {Mei Chai and Tian Xiao and Liu, Q.H.},
Title = {Large EMI/EMC simulations with the hybrid PSTD/FDTD
method},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {677 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {computational electromagnetics;electromagnetic
compatibility;electromagnetic interference;finite difference
time-domain analysis;},
Abstract = {In this work, we utilize a our recently developed hybrid
PSTD/FDTD method to simulate complex multiscale EMI/EMC
problems. In particular, we use the PSTD (pseudospectral
time-domain) method to model the regions with coarse
structures (feature size larger than a wavelengths, where
α ~ 1) since the PSTD method has spectral accuracy and
is efficient in this regime. On the other hand, the
alternating direction implicit conformal finite-difference
time-domain (ADI-CFDTD) method is used to model fine
structures (feature size smaller than β wavelengths,
where β ≪ 1) to speed up the time integration.
Finally, the conformal FDTD (CFDTD) method improved by the
enlarged cell technique (ECT) is used for the intermediate
scale. We demonstrate the significant saving in computer
memory and computation time for several realistic EMI/EMC
problems},
Key = {9198639}
}
@article{9198642,
Author = {Simsek, E. and Jianguo Liu and Liu, Q.H.},
Title = {A 3D spectral integral method for layered
media},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {685 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {conductors (electric);dielectric bodies;electromagnetic
fields;fast Fourier transforms;Green's function
methods;inhomogeneous media;integral equations;integration;interpolation;method
of moments;},
Abstract = {The surface integral equation (SIE) has been solved first
with method of moments (MOM) and then with fast multipole
method (FMM) to calculate the scattered electromagnetic
fields from a homogeneous scatter with arbitrary geometry in
a free space. Liu et al. developed a spectral integral
method (SIM) as an alternative way of solving the surface
integral equation more efficiently than MoM for
arbitrarily-shaped smooth dielectric cylinders in a free
space. Then Simsek et al. extend to arbitrarily-shaped
smooth perfect electrical conductor (PEC) and dielectric
cylinders in a multilayer medium in two dimensions. In this
work we extend this method to arbitrarily-shaped smooth PEC
and dielectric cylinders in a multilayer medium in three
dimensions. The main ingredients of this method are the use
of fast Fourier transform (FFT) algorithm and Fourier
interpolation, and the subtraction of singularities in
Green's functions to achieve a spectral accuracy in the
integral. Layered media Green's functions for layered media
are computed via numerical integration of a Sommerfeld type
integral. To obtain spectral accuracy in the SIM, it is
important that the Sommerfeld integration is obtained with
high precision through singularity subtraction. We have
demonstrated the spectral accuracy of this method and the
reduced computational cost from the MoM},
Key = {9198642}
}
@article{9175288,
Author = {Chun Yu and Simsek, E. and Liu, Q.H.},
Title = {Accurate simulation of electromagnetic waves scattered by 3D
objects in a multilayered medium by a surface integral
equation method},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {334 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {dielectric bodies;electromagnetic wave scattering;Green's
function methods;inhomogeneous media;integral
equations;},
Abstract = {In this paper, we investigate a surface integral equation
technique to simulate the radiation and scattering by
metallic and dielectric objects of arbitrary shape in the
presence of layered media. We focus on the cases where
scatterers straddle different layers in the multilayered
medium. The alternative form of the mixed-potential integral
formulation and multilayered-medium Green's function
representation is utilized, with the singularity subtraction
technique to accelerate the Sommerfeld integrals. As a
result of this succinct expression, the Green's function can
be calculated efficiently},
Key = {9175288}
}
@article{9175133,
Author = {Tian Xiao and Liu, Q.H.},
Title = {A flexible multiscale technique for electromagnetic
simulation},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {37 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {computational electromagnetics;},
Abstract = {In computational electromagnetics, problems in which the
structures span a large number of wavelengths and
geometrical scales are important for a variety of
applications. For such multiscale problems, to obtain a
certain accuracy, the discretization of the problem domain
is usually dominated by both the minimum wavelength and the
fine geometrical details, which results in an extreme
expensive overhead of computer resources. In the work, we
develop a flexible multiscale technique, which allows for a
free bridging of different scales in simulations},
Key = {9175133}
}
@article{9175289,
Author = {Jianguo Liu and Simsek, E. and Liu, Q.H.},
Title = {A 3-D spectral integral method for acoustic and
electromagnetic wave scattering},
Journal = {2006 IEEE Antennas and Propagation Society International
Symposium (IEEE Cat. No. 06CH37758C)},
Pages = {335 -},
Address = {Albuquerque, NM, USA},
Year = {2006},
Keywords = {acoustic wave scattering;electromagnetic wave
scattering;Fourier series;Helmholtz equations;integral
equations;Maxwell equations;},
Abstract = {In this paper, we propose to develop a spectral integral
method using Fourier series as basis functions. It provides
spectral accuracy with efficient computation, for solving
3-D acoustic and electromagnetic wave scattering problems.
Since we introduce Fourier series rather than conventional
spherical harmonics into the integral equation, this method
is more efficient than other existing 3-D integral equation
methods. Numerical examples are presented to investigate the
computational efficiency of the 3-D SIM},
Key = {9175289}
}
@article{9054416,
Author = {Ye, G and Lim, KH and George, R and Ybarra, G and Joines, WT and Liu,
QH},
Title = {A 3D EIT system for breast cancer imaging},
Journal = {2006 3rd Ieee International Symposium on Biomedical Imaging:
From Nano to Macro Proceedings},
Volume = {2006},
Pages = {1092-1095},
Address = {Arlington, VA, USA},
Year = {2006},
Keywords = {bioelectric potentials;biological organs;cancer;electric
impedance imaging;gynaecology;image reconstruction;medical
image processing;phantoms;tumours;},
Abstract = {Electrical impedance tomography (EIT) is a developing and
promising imaging modality for early detection of breast
cancer. An EIT system utilizes an array of electrodes to
apply currents to an imaging domain and measures the
resulting voltages on the periphery. The measurement results
are then input to a reconstruction algorithm to produce an
image of the impedance distribution inside the domain. In
this work, a full 3D BIT system has been developed and the
system design, measurement strategy and reconstruction
algorithm are presented. Several sets of experimental data
are collected and phantom tumor images are reconstructed
from these data sets. © 2006 IEEE.},
Key = {9054416}
}
@article{fds283783,
Author = {Song, J and Liu, QH and Torrione, P and Collins, L},
Title = {Two-dimensional and three-dimensional NUFFT migration method
for landmine detection using ground-penetrating
radar},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {44},
Number = {6},
Pages = {1462-1469},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2006.870412},
Abstract = {Ground-penetrating radar (GPR) has been widely used for
landmine detection due to its high signal-to-noise ratio
(SNR) and superior ability to image nonmetallic landmines.
Processing GPR data to obtain better target images and to
assist further object detection has been an active research
area. Phase-shift migration is a widely used method;
however, its wavenumber space is nonuniformly sampled
because of the nonlinear relationship between the uniform
frequency samples and the wavenumbers. Conventional methods
use linear interpolation to obtain uniform wavenumber
samples and compute the fast Fourier transform (TFT). This
paper develops two- and three-dimensional migration methods
that process GPR data to obtain images close to the actual
target geometries using a nonuniform fast Fourier transform
(NUFFT) algorithm. The proposed method is first compared to
the conventional migration approaches on simulated data and
then applied to landmine field data sets. Results suggest
that the NUFFT migration method is useful in focusing
images, estimating landmine structure, and retaining
relatively high signal-to-noise ratio in the migrated data.
The processed data sets are then fed to the normalized
energy and least-mean-square-based anomaly detectors.
Receiver operating characteristic curves of data sets
processed by different migration methods are compared. The
NUFFT migration shows potential improvements on both
classifiers with a reduced false alarm rate at most
probabilities of detection. © 2006 IEEE.},
Doi = {10.1109/TGRS.2006.870412},
Key = {fds283783}
}
@article{8962014,
Author = {Lee, J-H and Xiao, T and Liu, QH},
Title = {A 3-D spectral-element method using mixed-order curl
conforming vector basis functions for electromagnetic
fields},
Journal = {Ieee Trans. Microw. Theory Tech. (Usa)},
Volume = {54},
Number = {1},
Pages = {437-444},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/TMTT.2005.860502},
Keywords = {electromagnetic fields;electromagnetic wave
propagation;finite element analysis;Legendre
polynomials;spectral analysis;},
Abstract = {A three-dimensional spectral-element method (SEM) based on
Gauss-Lobatto-Legendre polynomials is proposed to solve
vector electromagnetic-wave equations. To suppress spurious
solutions, mixed-order curl conforming vector basis
functions are used in the SEM. The advantages of this method
include its high-order accuracy and its diagonal mass matrix
due to the use of orthogonal Legendre polynomials. Thus, the
proposed method leads to a regular eigenvalue problem rather
than a generalized eigenvalue problem, greatly reducing the
computer memory requirement and CPU time in comparison with
the conventional high-order finite-element method (FEM).
Numerical examples of eigenvalue problems verify the
spectral accuracy with the interpolation orders and show
that the SEM is superior to the FEM for the class of
problems considered. A waveguide model is analyzed with
mixed boundary conditions and its results are in excellent
agreement with reference values. All numerical results show
that the SEM is an efficient alternative to the FEM for
electromagnetic fields},
Doi = {10.1109/TMTT.2005.860502},
Key = {8962014}
}
@article{9080710,
Author = {Chen, Y and Joines, WT and Xie, Z and Shi, G and Liu, QH and Carin,
L},
Title = {Double-sided exponentially tapered GPR antenna and its
transmission line feed structure},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {54},
Number = {9},
Pages = {2615-2622},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2006.880729},
Keywords = {antenna feeds;antenna radiation patterns;broadband
antennas;dipole antenna arrays;ground penetrating
radar;radar antennas;radar detection;time-domain
analysis;},
Abstract = {A double-sided broadband antenna for applications including
ground-penetrating radar for detecting buried target is
described. When compared with traditional coplanar-strip
antennas, a better performance is achieved with a more
practical design for construction. The steps in the design
procedure are demonstrated herein. In addition, using
incremental segments of current elements, a distributed
dipole array model is derived and presented for determining
S11 in the time domain and for determining the radiation
pattern of this antenna. By comparing measured results and
HFSS simulations, our straightforward dipole array model of
the more complicated antenna structure is justified by the
accuracy of the results obtained. Finally, an experimental
example is presented to show that this antenna in a GPR
system application is effective in detecting even small
plastic targets. © 2006 IEEE.},
Doi = {10.1109/TAP.2006.880729},
Key = {9080710}
}
@article{8820917,
Author = {Xiao, T and Liu, and H, Q},
Title = {Reply to `Comment on "Enlarged cells for the conformal FDTD
method to avoid the time step reduction"'},
Journal = {Ieee Microw. Wirel. Compon. Lett. (Usa)},
Volume = {16},
Number = {1},
Pages = {55-56},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2006},
url = {http://dx.doi.org/10.1109/LMWC.2005.861551},
Keywords = {computational electromagnetics;electromagnetic field
theory;finite difference time-domain analysis;},
Abstract = {For original article by T. Xiao and Q.H. Liu see ibid.,
vol.14, no.12, p.551-3, Dec. 2004. For comments by R.
Schuhmann, I.A. Zagorodnov and T. Weiland see ibid., vol.16,
no.1, p.55, Jan. 2006},
Doi = {10.1109/LMWC.2005.861551},
Key = {8820917}
}
@article{8920730,
Author = {Liu, Y and Lee, J-H and Xiao, T and Liu, QH},
Title = {A spectral-element time-domain solution of Maxwell's
equations},
Journal = {Microw. Opt. Technol. Lett. (Usa)},
Volume = {48},
Number = {4},
Pages = {673-680},
Publisher = {WILEY},
Year = {2006},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.21440},
Keywords = {Legendre polynomials;Maxwell equations;time-domain
analysis;},
Abstract = {A spectral-element time-domain (SETD) method based on
Gauss-Lobatto-Legendre (GLL) polynomials is presented to
solve Maxwell's equations. The proposed SETD method combines
the advantages of spectral accuracy with the geometric
flexibility of unstructured grids. In addition, a 4th-order
Runge-Kutta method for time integration provides high-order
accuracy and thus reduces the temporal discretization
errors. The numerical results demonstrate its spectral
accuracy with the order of basis function and show the high
efficiency of the proposed method due to its exponential
convergence},
Doi = {10.1002/mop.21440},
Key = {8920730}
}
@article{8652860,
Author = {Xiao, T and Liu, QH},
Title = {An enlarged cell technique for the conformal FDTD method to
model perfectly conducting objects},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {1 A},
Pages = {122-125},
Publisher = {IEEE},
Address = {Washington, DC, USA},
Year = {2005},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2005.1551259},
Keywords = {computational electromagnetics;conducting bodies;finite
difference time-domain analysis;},
Abstract = {A conformal finite-difference time-domain (CFDTD) method has
been put forward by S. Dey and R. Mittra (see IEEE Microwave
Guided Wave Lett., vol.7, p.273-5, 1997) to model curved
perfectly conducting objects. The method deforms the grid
locally to accommodate the curvature of the PEC surface, and
therefore, avoids the staircase error of the conventional
FDTD method in approximating boundaries. However, sometimes
the deformed grid may be too small to obtain a stable
solution. This instability can be removed by using a smaller
time step, at the expense of more times steps being
required. We introduce an efficient, yet accurate,
technique, the enlarged cell technique (ECT), to obtain a
stable solution without the need to reduce the time step
(Xiao, T. and Liu, Q.H., IEEE Microwave Wireless Compon.
Lett., vol.14, p.551-3, 2004). This technique has a clear
geometric and physical explanation and is easy to implement.
Unlike CFDTD methods, the ECT sacrifices neither accuracy
nor efficiency in treating small distorted
cells},
Doi = {10.1109/APS.2005.1551259},
Key = {8652860}
}
@article{8670917,
Author = {Song, LP and Yu, C and Liu, QH},
Title = {2-D nonlinear image reconstruction for objects buried in
layered media},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2 A},
Pages = {115-118},
Publisher = {IEEE},
Address = {Washington, DC, USA},
Year = {2005},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2005.1551750},
Keywords = {buried object detection;electromagnetic wave
propagation;electromagnetic wave scattering;image
reconstruction;inhomogeneous media;integral
equations;inverse problems;},
Abstract = {In this paper, a contrast source inversion (CSI)-based
nonlinear inversion method is developed for imaging
reconstruction of buried objects in 2D layered media. First,
the CSI method and relevant integral equation formulation is
briefly described. Then some examples of the 2D inversion
for objects buried in a multilayered medium are presented to
illustrate the effectiveness of the method},
Doi = {10.1109/APS.2005.1551750},
Key = {8670917}
}
@article{fds283642,
Author = {Millard, X and Liu, QH and Harrell, D},
Title = {An accurate conjugate gradient fast fourier transform method
for electromagnetic scattering},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {3 B},
Pages = {196-199},
Publisher = {IEEE},
Year = {2005},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2005.1552469},
Abstract = {An accurate conjugate gradient fast Fourier transform
(CG-FFT) for solving electromagnetic scattering problems is
developed by improving the accuracy of estimating the
spectrum of the Green's function. Comparing to the
traditional CG-FFT algorithm, this new approach reduces the
relative error by a factor of 5 to 20 for one-dimensional
electromagnetic scattering models while maintaining the
computational cost in terms of CPU time and memory
requirement. © 2005 IEEE.},
Doi = {10.1109/APS.2005.1552469},
Key = {fds283642}
}
@article{8670918,
Author = {Song, LP and Yu, C and Liu, QH},
Title = {Image reconstruction from measured scattering
data},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2 A},
Pages = {119-122},
Publisher = {IEEE},
Address = {Washington, DC, USA},
Year = {2005},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2005.1551751},
Keywords = {electromagnetic wave scattering;image reconstruction;imaging;inhomogeneous
media;},
Abstract = {We present our recent work on the image reconstruction of
two dimensional scattering objects using the layered-medium
contrast source inversion (CSI) method from the measured
scattering data collected in June 2004 from Institut
Fresnel. We focus on the TM case. Even though the Fresnel
data sets were collected from the EM chamber that simulates
a homogeneous background, it provided real data for
validation test of our layered-medium contrast source
inversion algorithm and procedure (when degenerating to a
one layer medium)},
Doi = {10.1109/APS.2005.1551751},
Key = {8670918}
}
@article{fds283644,
Author = {Xu, Y and Wang, Z and Liu, Q},
Title = {Research on the method of inductance calculation in power
transformer simulation model},
Journal = {7th International Power Engineering Conference,
Ipec2005},
Volume = {2005},
Year = {2005},
Month = {December},
Abstract = {In order to calculate the inductance of transformer
simulation model, this paper presents a new calculation
method based on transformer magnetic circuit. This method
calculates the mutual inductance and leakage inductance
respectively. When calculating the leakage inductance, the
effect of vertical leakage flux and horizontal leakage flux
have been considered, which makes the calculating result are
more correct. In order to prove the validity of this method,
the data of simulation test and dynamic analog test have
been compared. The results have proved that the method of
magnetic circuit calculation is accurate.},
Key = {fds283644}
}
@article{fds283648,
Author = {Yu, C and Song, LP and Liu, QH},
Title = {Inversion of multi-frequency experimental data for imaging
complex objects by a DTA-CSI method},
Journal = {Inverse Problems},
Volume = {21},
Number = {6},
Pages = {S165-S178},
Publisher = {IOP Publishing},
Year = {2005},
Month = {December},
ISSN = {0266-5611},
url = {http://dx.doi.org/10.1088/0266-5611/21/6/S12},
Abstract = {This paper deals with image reconstruction from measured
multi-frequency scattering data for 2D inhomogeneous targets
by using a technique combining the diagonal tensor
approximation (DTA) and contrast source inversion (CSI)
methods. In this algorithm, the diagonal tensor
approximation is applied as a nonlinear approximation of the
2D domain integral equation for an inverse scattering
problem, and is used as an initial guess for the nonlinear
contrast source inversion. Taking advantage of the
properties of fast convergence of the DTA operator and
stable convergence of the CSI method, the combined technique
makes image reconstructions more effective. Using this
combined approach, the multi-frequency experimental data
from Institut Fresnel have been processed, and excellent
reconstruction results have been obtained for inhomogeneous
targets. © 2005 IOP Publishing Ltd.},
Doi = {10.1088/0266-5611/21/6/S12},
Key = {fds283648}
}
@article{fds283649,
Author = {Song, LP and Yu, C and Liu, QH},
Title = {Through-wall imaging (TWI) by radar: 2-D tomographic results
and analyses},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {43},
Number = {12},
Pages = {2793-2798},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2005},
Month = {December},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2005.857914},
Abstract = {A two-dimensional nonlinear inverse scattering technique is
developed for imaging objects in a multilayered medium that
simulates the effects of building walls in the context of
through-wall imaging (TWI). The effectiveness and capacity
of the inversion algorithm and the feasibility of
through-wall imaging is demonstrated via a number of
numerical examples. It has been shown that using
multifrequency data high-quality image reconstruction can be
achieved with a limited array view. © 2005
IEEE.},
Doi = {10.1109/TGRS.2005.857914},
Key = {fds283649}
}
@article{fds283650,
Author = {Lee, JH and Liu, QH},
Title = {An efficient 3-D spectral-element method for schrödinger
equation in nanodevice simulation},
Journal = {Ieee Transactions on Computer Aided Design of Integrated
Circuits and Systems},
Volume = {24},
Number = {12},
Pages = {1848-1858},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2005},
Month = {December},
ISSN = {0278-0070},
url = {http://dx.doi.org/10.1109/TCAD.2005.852675},
Abstract = {A three-dimensional (3-D) spectral-element method (SEM)
based on Gauss-Lobatto-Legendre (GLL) polynomials is
proposed to solve the Schrödinger equation in nanodevice
simulation. Galerkin's method is employed to obtain the
system equation. The high-order basis functions employed are
orthogonal and the numerical quadrature points are the same
as the GLL integration points, leading to a diagonal mass
matrix and a more sparse stiffness matrix. Thus, the
proposed method leads to a regular eigenvalue problem,
rather than a generalized eigenvalue problem, greatly
reducing the computer-memory requirement and
central-processing-unit (CPU) time in comparison with the
conventional finite-element method (FEM). Furthermore, the
SEM is implemented for high geometrical orders, where curved
structures can be modeled up to the accuracy comparable to
the interpolation accuracy afforded by the basis functions.
Numerical examples verify a spectral accuracy with the
interpolation orders, and confirm that higher geometrical
orders are essential for curved structures to achieve
overall spectral accuracy. Examples of quantum dots in
various structures, including a waveguide, are analyzed with
mixed boundary conditions. Numerical results show that the
SEM is an efficient alternative to conventional FEM and to
the finite-difference method (FDM) for nanodevice
simulation. © 2005 IEEE.},
Doi = {10.1109/TCAD.2005.852675},
Key = {fds283650}
}
@article{fds283767,
Author = {Simsek, E and Liu, J and Liu, QH},
Title = {A spectral integral method for layered media},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {3 B},
Pages = {238},
Publisher = {IEEE},
Year = {2005},
Month = {December},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/APS.2005.1552481},
Abstract = {In order to solve layered-medium problems in areas such as
interconnect simulations and subsurface sensing, various
numerical methods such as finite difference time domain
methods, finite element methods, the method of moments
(MoM), and the fast multipole method (FMM), have been
developed. In this work, we are concerned with piecewise
homogeneous objects embedded in a layered medium. As such,
the surface integral equation (SIE) can be used to reduce
the number of the unknowns compared with the volume integral
equation. The SIE has been solved first with MOM and then
with FMM to calculate the scattered electromagnetic fields
from a homogeneous scatter with arbitrary geometry in a free
space. Liu et.al. developed a spectral integral method (SIM)
as an alternative way of solving the surface integral
equation more efficiently than MOM (J. Liu and Q. H. Liu,
IEEE Micro, and Wire. Comp. Lett., 14, 3, 97-99, 2004) for
arbitrarily-shaped smooth dielectric cylinders in a free
space. In this work we extend this method to
arbitrarily-shaped smooth perfect electrical conductor (PEC)
and dielectric cylinders in a multilayer medium. The main
ingredients of this method are the use of fast Fourier
transform (FFT) algorithm and the subtraction of
singularities in Green's functions to achieve a spectral
accuracy in the integral. 2D Green's functions for layered
media are computed via numerical integration of a Sommerfeld
type integral. To obtain spectral accuracy in the SIM, it is
important that the Sommerfeld integration is obtained with
high precision through singularity subtraction. We have
demonstrated the spectral accuracy of this method and the
reduced computational cost from the MOM. This method can
also be extended to three dimensions. ©2005
IEEE.},
Doi = {10.1109/APS.2005.1552481},
Key = {fds283767}
}
@article{fds283647,
Author = {Song, LP and Şimşek, E and Liu, QH},
Title = {A fast 2D volume integral-equation solver for scattering
from inhomogeneous objects in layered media},
Journal = {Microwave and Optical Technology Letters},
Volume = {47},
Number = {2},
Pages = {128-134},
Publisher = {WILEY},
Year = {2005},
Month = {October},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.21101},
Abstract = {The stabilized biconjugate gradient fast Fourier transform
(BCGS-FFT) method is applied to simulate electromagnetic and
acoustic scattering from inhomogeneous objects embedded in a
layered medium in two dimensions. Two-dimensional
layered-media Green's functions are computed adoptively by
using Gaussian quadratures after singularity subtraction.
The Green 's function is split into convolutional and
correlational components in order to apply the FFT so as to
solve the scattering problem efficiently. The CPU time and
memory cost of this BCGS-FFT method is O(N log N) and O(N),
respectively, where N is the number of unknowns, which is
significantly more efficient than using the method of
moments (MoM). As a result, this method is capable of
solving large-scale electromagnetic and acoustic scattering
problems for inhomogeneous objects embedded in a layered
medium with an arbitrary number of layers. © 2005 Wiley
Periodicals, Inc.},
Doi = {10.1002/mop.21101},
Key = {fds283647}
}
@article{8611492,
Author = {Xiao, T and Liu, QH},
Title = {Three-dimensional unstructured-grid discontinuous Galerkin
method for Maxwell's equations with well-posed perfectly
matched layer},
Journal = {Microwave and Optical Technology Letters},
Volume = {46},
Number = {5},
Pages = {459-463},
Publisher = {WILEY},
Year = {2005},
Month = {September},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.21016},
Keywords = {electromagnetic wave absorption;electromagnetic wave
propagation;Galerkin method;Maxwell equations;photonic band
gap;},
Abstract = {In this paper, a 3D discontinuous Galerkin method (DGM) is
developed to solve Maxwell's equations. It utilizes an
unstructured grid, where objects are divided into a number
of tetrahedrons. To model the propagation of electromagnetic
waves in an open region, a well-posed perfectly matched
layer (PML) is applied to truncate the computational domain
by absorbing outgoing waves. The analyses show that this
method is highly accurate and efficient and has the ability
to accurately model curved objects. Therefore, it is
well-suited for modeling large-scale, broadband problems
with complex geometries. Some examples, including a photonic
bandgap structure, are shown to illustrate the features and
applications of this discontinuous Galerkin method. © 2005
Wiley Periodicals, Inc.},
Doi = {10.1002/mop.21016},
Key = {8611492}
}
@article{fds283645,
Author = {Song, LP and Liu, QH and Li, F and Zhang, ZQ},
Title = {Reconstruction of three-dimensional objects in layered
media: Numerical experiments},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {53},
Number = {4},
Pages = {1556-1561},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2005},
Month = {April},
url = {http://dx.doi.org/10.1109/TAP.2004.842585},
Abstract = {We have developed a fully three-dimensional electromagnetic
inverse scattering technique in a multilayered medium via
the contrast source inversion. The key issues on the
three-dimensional (3-D) forward and adjoint operations
related to the dyadic Green's operators are briefly
addressed to ensure the efficient performance of the
algorithm in layered media. It is shown that it is feasible
to achieve good reconstruction quality with only a few
sources and a two-dimensional receiver array, provided that
the signal-to-noise ratio is adequate. The effects of the
interface and of the uncertainty in the background layered
medium are illustrated in the simulation. The developed 3-D
electromagnetic inverse scattering technique can be
effectively applied to surface ground penetrating radar
survey in multilayered media. © 2005 IEEE.},
Doi = {10.1109/TAP.2004.842585},
Key = {fds283645}
}
@article{fds283646,
Author = {Song, LP and Liu, QH},
Title = {A new approximation to three-dimensional electromagnetic
scattering},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {2},
Number = {2},
Pages = {238-242},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2005},
Month = {April},
url = {http://dx.doi.org/10.1109/LGRS.2005.846836},
Abstract = {We introduce a new source-dependent but diagonal scattering
tensor to approximate the electromagnetic fields internal to
a scatterer. The approximate analytical expressions for the
three diagonal scattering components are derived. Numerical
tests show that the new approximation has favorable accuracy
and wider range of applicability than the existing
approximations such as the widely used extended Born
approximation and the quasi-analytical approximation. ©
2005 IEEE.},
Doi = {10.1109/LGRS.2005.846836},
Key = {fds283646}
}
@article{fds314354,
Author = {Liu, Q and Wang, ZP and Xu, Y and Jiao, YJ and Qu, YH},
Title = {Research on the influence of optical current transducer on
protective relaying system},
Journal = {Dianwang Jishu/Power System Technology},
Volume = {29},
Number = {1},
Pages = {11-14+29},
Year = {2005},
Month = {January},
ISSN = {1000-3673},
Abstract = {The appearance of new types of CTs represented by optical
current transducer (OCT) solves the difficulties of
saturation and low transient accuracy of traditional
electromagnetic CTs used in protective relaying. According
to the working principle and features of the OCT based on
the Faraday magneto-optical effect and based on the seamless
communication protocol in IEC 61850, a scheme to implement
the interface between OCT and microprocessor based
protection device by optical Ethernet is proposed. Through
the comparison between the protective device adopting OCT
and that adopting traditional electromagnetic CT, the
conclusion that sensitivity and reliability of protective
relaying can be remarkably improved by use of OCT is
obtained.},
Key = {fds314354}
}
@article{fds283639,
Author = {Song, LP and Liu, QH},
Title = {Ground-penetrating radar land mine imaging: Two-dimensional
seismic migration and three-dimensional inverse scattering
in layered media},
Journal = {Radio Science},
Volume = {40},
Number = {1},
Pages = {n/a-n/a},
Publisher = {American Geophysical Union (AGU)},
Year = {2005},
Month = {January},
url = {http://dx.doi.org/10.1029/2004RS003087},
Abstract = {This paper presents two methods for ground-penetrating radar
(GPR) imaging of land mines: a two-dimensional (2-D) seismic
migration method and a 3-D nonlinear inverse scattering
method. The seismic migration technique has been
successfully applied to processing field data sets collected
at a test site. The results show that the seismic migration
technique is a useful real-time imaging method. To image the
3-D structure of the land mine, we have developed a full 3-D
nonlinear inverse scattering algorithm on the basis of the
contrast source inversion method. To account for the ground
surface and potentially other subsurface layers, the inverse
scattering method uses a multilayered medium as a
background. Preliminary results demonstrate that the 3-D
inverse scattering method can successfully provide
high-resolution reconstruction of high-contrast buried
objects. Copyright 2005 by the American Geophysical
Union.},
Doi = {10.1029/2004RS003087},
Key = {fds283639}
}
@article{8474539,
Author = {Wartenberg, SA and Zhao, G and Liu, QH},
Title = {Electro-thermal resistance of GaAs interconnects},
Journal = {Journal of Electronic Materials},
Volume = {34},
Number = {3},
Pages = {294-298},
Publisher = {Springer Nature},
Year = {2005},
Month = {January},
ISSN = {0361-5235},
url = {http://dx.doi.org/10.1007/s11664-005-0216-0},
Keywords = {dielectric materials;electrical resistivity;gallium
arsenide;III-V semiconductors;interconnections;semiconductor
epitaxial layers;semiconductor technology;thermal
conductivity;},
Abstract = {This paper describes the effect of steady-state heating on
the electrical and thermal resistance of interconnects on
GaAs. Examined is a typical dual-layer metal interconnect
system, common to GaAs processing. The interconnect system
is considered in three parts, the interconnect metals, the
Si3N4 dielectric surrounding the metal, and the Al xGa1-xAs
epitaxial substrate. Using a meandering line as a test
structure, measurements show how the direct current (DC)
resistance increases with both temperature and dissipated
power. Thermal resistors are proposed to account for
self-heating and thermal coupling.},
Doi = {10.1007/s11664-005-0216-0},
Key = {8474539}
}
@article{fds283785,
Author = {Liu, D and Kang, G and Li, L and Chen, Y and Vasudevan, S and Joines, W and Liu, QH and Krolik, J and Carin, L},
Title = {Electromagnetic time-reversal imaging of a target in a
cluttered environment},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {53},
Number = {9},
Pages = {3058-3066},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2005},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/TAP.2005.854563},
Abstract = {Electromagnetic time-reversal imaging is addressed for a
target situated in a cluttered background. We first
investigate the theory of electromagnetic time-reversal
imaging, followed by an experimental demonstration. A
transmitter-receiver antenna array is connected to a network
analyzer and applied to transmit wideband waveforms for
detecting a target within a cluttered environment. We assume
the cluttered background is fixed, thus the target signature
is extracted by observing changes manifested by the
introduction of a target. A numerical algorithm is required
for computation of the Green's function employed within the
time-reversal imager, with this implemented here via ray
tracing. Example time-reversal images of different cluttered
backgrounds and different targets are presented using
measured data, with comparisons to a traditional radar
imaging technique. Results show that the time-reversal
imagery yields good focusing at the target, significantly
better than when the background is not accounted for. ©
2005 IEEE.},
Doi = {10.1109/TAP.2005.854563},
Key = {fds283785}
}
@article{8646206,
Author = {Qi, WH and Wang, MP and Liu, QH},
Title = {Shape factor of nonspherical nanoparticles},
Journal = {J. Mater. Sci. (Usa)},
Volume = {40},
Number = {9-10},
Pages = {2737-2739},
Publisher = {Springer Science and Business Media LLC},
Year = {2005},
url = {http://dx.doi.org/10.1007/s10853-005-2119-0},
Keywords = {nanoparticles;},
Abstract = {This paper proposes a new parameter called the "shape
factor" in order to account the particle shape difference
between spherical nanoparticles and nonspherical
nanoparticles. The shape factor of special shape have been
calculated},
Doi = {10.1007/s10853-005-2119-0},
Key = {8646206}
}
@article{9206735,
Author = {Chen, Y and Joines, WT and Chai, M and Liu, QH and Carin,
L},
Title = {Analysis, design, and construction of a broadband balun for
coaxial-to-planar transmission lines},
Journal = {Microwave and Optical Technology Letters},
Volume = {44},
Number = {6},
Pages = {501-504},
Publisher = {WILEY},
Year = {2005},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.20679},
Keywords = {antenna feeds;baluns;broadband antennas;coaxial
cables;microstrip lines;microwave antennas;parallel plate
waveguides;},
Abstract = {For microwave signals within the 0.5 to 10.5 GHz range, we
present an integrated broadband balun that carries signals
from co-axial cable to microstrip to parallel-plate line. We
use this arrangement as the feed line for a broadband
double-sided antenna, and this antenna feed is presented as
an application of the integrated balun. In addition, we
devise a testing method for the balun, which is
demonstrated. Through this testing method, the transmission,
reflection, and radiation losses associated with the balun
are readily determined. © 2005 Wiley Periodicals,
Inc.},
Doi = {10.1002/mop.20679},
Key = {9206735}
}
@article{fds283554,
Author = {Tang, Y and Liu, Q and Chen, LF and Du, Y},
Title = {Normalization of Sun/View angle effects in vegetation index
using BRDF of typical crops},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {6},
Pages = {4063-4065},
Year = {2004},
Month = {December},
Abstract = {Vegetation indices are subjected to many external
perturbations such as soil background variations,
atmospheric conditions, geometric registration, and
especially sensor viewing geometry. Subsequent use of these
indices to estimate crop yield and monitor crops growth
would result in substantial uncertainties. To reduce the
uncertainties due to sun-view angle variations, some methods
were generated by use the reflectance or albedo generated
from the BRDF models. MODIS vegetation composition algorithm
uses the empirical BRDF model (developed by Walthall et al)
to normalize the Sun/View angles to certain angle, and then
composite the VI by several day's data. In this paper, we
present a new method based on prior knowledge to normalize
vegetation index on pure pixels of crops, which can be
recognized from MODIS image by high resolution land cover
map. We simulated different BRDFs of winter wheat in
different grow stages by radiative transfer models, using
the plant canopy parameters obtained from prior knowledge.
Then, we use this BRDF to normalize vegetation indices. The
method was tested by the ground based measurements and MODIS
Data. It shows our results are good consistent with the
ground based measurements. We compare our methods with the
algorithm of MODIS vegetation composition, it proved that
the result calculated by our method is in better agreement
with the surface reflectance characterizations and our
method is more effective to monitor the crop growth in
regional scale.},
Key = {fds283554}
}
@article{8305588,
Author = {Du, Y and Chen, LF and Yang, L and Liu, QH},
Title = {Inversion and spatial scale effects analysis of leaf area
index},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {7},
Pages = {4474-4476},
Address = {Anchorage, AK, USA},
Year = {2004},
Month = {December},
Keywords = {geophysical signal processing;image resolution;vegetation
mapping;},
Abstract = {This paper presents an application in which field data, TM
data and MODIS data are used for mapping LAI of Qianyanzhou
in Jiangxi province, south China. The field LAI data are
collected by Tracing Radiation and Architecture of Canopies
(TRAC). We get the linear relationship between measured LAI
and simple ratio vegetation index (SR: the ratio of NIR
reflectance and Red reflectance) from the corresponding
pixels, then the LAI image from TM date is produced and is
referred as LAI ground true for further studies. After
comparing and analyzing the different LAI images, it shows
that the uncertainties really existed among the different
kinds of the LAI images with same resolution, it also
reveals that the spatial upscaling effects are closely
related to sub-pixel complicacy.},
Key = {8305588}
}
@article{fds283623,
Author = {Xiao, T and Liu, QH and He, J},
Title = {Application of the Enlarged Cell Method (ECM) to EMI/EMC
problems},
Journal = {Ieee Topical Meeting on Electrical Performance of Electronic
Packaging},
Pages = {333-336},
Publisher = {IEEE},
Year = {2004},
Month = {December},
url = {http://dx.doi.org/10.1109/epep.2004.1407626},
Abstract = {Conductors play an important role in the EMI/EMC problem.
However, the conventional finite-difference time-domain
(FDTD) method is known to produce significant staircasing
errors when applied to conductors. In the past few years,
many researchers have been using conformal FDTD methods to
reduce this staircasing error. As a side effect, however,
the time step size in these conformal FDTD (CFDTD) methods
often becomes more restrictive because of the reduced
effective grid size near the conductor boundary. In this
paper, an enlarged cell method is applied to solve EMI/EMC
problems. We show that the ECM is highly accurate compared
to the conventional FDTD method, and is three times faster
than the conformal FDTD method because the time step size in
ECM remains the same as in the FDTD method. Large-scale
EMI/EMC problems have been solved with the ECM on a PC. ©
2004 IEEE.},
Doi = {10.1109/epep.2004.1407626},
Key = {fds283623}
}
@article{fds283624,
Author = {Du, Y and Liu, Q and Liu, QH and Chen, LF},
Title = {Estimate LAI of crops using airborne multi-angular
data},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {7},
Pages = {4477-4479},
Year = {2004},
Month = {December},
Abstract = {Usually we use multi-channel image data, such as TM, and
empirical relationship, such as NDVI-LAI relation or SR-LAI
relation, to estimate LAI. While multi-angular remote
sensing data provide more information for canopy structure.
This paper presents a method to estimate LAI using
multi-angular data and model inversion method. The airborne
multi-angular data was acquired by AMTIS (Airborne
Multi-angle TIR/VNIR Imaging System), which was a prototype
sensor designed by institute of remote sensing applications
of Chinese Academy of Science. Our study is based on two
datasets: one was acquired in Beijing Shunyi in April 11,
and the major crop is sparse winter wheat; another was
acquired in Haerbin in August 24, and major crops are dense
corn and soybean. Both datasets have been geometrically
atmospherically corrected. Ground based measurements were
carried out during the flight experiment. SAIL model is
chosen to predict reflected radiance of a presumed LAI.
Various view angles relate to the different components ratio
in view field, and the reflected radiance will be different
accordingly. So a certain LAI value was given, SAIL model
will predict a set of reflected radiances of various angles.
We compare the model predict radiance with the radiance
viewed by multi-angular sensor, to find the optimized LAI
which can make the radiance predicted by model be closest to
the viewed radiance, then take this LAI value as the right
value.},
Key = {fds283624}
}
@article{fds283625,
Author = {Sinha, BK and Liu, QH},
Title = {Elastic waves in deviated boreholes in formations with
triaxial stresses},
Journal = {Proceedings Ieee Ultrasonics Symposium},
Volume = {1},
Pages = {525-528},
Year = {2004},
Month = {December},
Abstract = {A new 3D-finite-difference formulation of equations of
motion for elastic waves in prestressed formations has been
used to calculate synthetic waveforms at an array of
receivers in a liquid-filled borehole. These equations
describe the influence of borehole hydrostatic pressure as
well as triaxial formation stresses on elastic waves
produced by either a monopole or dipole transmitter placed
on the borehole axis. The synthetic waveforms are processed
by a slowness-time coherence (STC) and modified matrix
pencil algorithms for isolating both non-dispersive and
dispersive arrivals in the wavetrain. Computational results
for the formation compressional, fast-shear, and slow-shear
slownesses obtained from synthetic waveforms in a wellbore
with deviations of 0°, 30°, and 60° from the vertical are
consistent with the rotated stresses referred to the hole
measurement axes. Compressional slowness changes are
primarily affected by changes in the stress along the
propagation direction. In contrast, shear slowness changes
are equally affected by stress changes either in the
propagation or radial polarization direction. © 2004
IEEE.},
Key = {fds283625}
}
@article{fds283626,
Author = {Cheng, C and Liu, QH and Massoud, HZ},
Title = {Spectral element method for the schrödinger-poisson
system},
Journal = {2004 10th International Workshop on Computational
Electronics, Ieee Iwce 10 2004, Abstracts},
Pages = {221-222},
Year = {2004},
Month = {December},
Abstract = {The development of a fast spectral element method (SEM) with
exponential accuracy for the self-consistent solution of the
Schrödinger-Poisson system for the simulation of
semiconductor nanodevices was presented.
Gauss-Lobatto-Legendre polynomials were used to represent
the unknown fields Schrödinger and Poisson equations. The
spectral element method was first applied on an infinite
quantum well under an external bias to solve the
Schrödinger equation. It was observed that the spectral
element method had an exponential accuracy. while the
finite-difference method only had a 2nd order
accuracy.},
Key = {fds283626}
}
@article{fds283638,
Author = {Song, LP and Liu, QH},
Title = {Fast three-dimensional electromagnetic nonlinear inversion
in layered media with a novel scattering
approximation},
Journal = {Inverse Problems},
Volume = {20},
Number = {6},
Pages = {S171-S194},
Publisher = {IOP Publishing},
Year = {2004},
Month = {December},
ISSN = {0266-5611},
url = {http://dx.doi.org/10.1088/0266-5611/20/6/S11},
Abstract = {This paper presents a fast three-dimensional (3D)
electromagnetic nonlinear inversion method in a multilayered
medium via a novel scattering approximation. Using the
superposition principle, we introduce a new source-dependent
but diagonal scattering tensor. The approximate analytical
expressions for the three scattering diagonal components are
derived. Numerical tests show that the new approximation has
better accuracy and wider range of applicability than the
existing approximations such as the extended Born
approximation and the quasi-analytical approximation. The
computational speed of the new scattering approximation is
essentially the same as the Born approximation. With such a
new approximation, we further develop an efficient
linearized 3D electromagnetic inversion method in a layered
medium. In this method, the inverse problem is cast into a
weighted least-squares problem solved via a conjugate
gradient scheme. In terms of eigenvalue analysis, we propose
a choice of the data and model weighting matrices that can
be constructed for a general, complex Fréchet sensitivity
matrix. The suggested weights help the selection of the
regularization factor within the specified range of [0,1]
for the inverse problem, and improves the condition of the
original imaging system. Synthetic tomography experiments
demonstrate the efficiency of the new scattering
approximation and the fast 3D EM imaging
technique.},
Doi = {10.1088/0266-5611/20/6/S11},
Key = {fds283638}
}
@article{8217810,
Author = {Xiao, T and Liu, QH},
Title = {Enlarged cells for the conformal FDTD method to avoid the
time step reduction},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {14},
Number = {12},
Pages = {551-553},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {December},
url = {http://dx.doi.org/10.1109/LMWC.2004.837384},
Keywords = {computational electromagnetics;electromagnetic field
theory;finite difference time-domain analysis;},
Abstract = {Recently, the conformal finite-difference time-domain
(CFDTD) method has emerged as an efficient FDTD method with
a higher order accuracy than the conventional FDTD methods
that are degraded by staircasing errors. The only obvious
point to further improve on the CFDTD method is its
requirement for a smaller time step increment due to the
existence of small irregular cells near the boundary. In
this letter, an enlarged cell technique is introduced to
ensure the stability of the CFDTD method without the time
step reduction. The introduction of the enlarged cells
therefore makes the CFDTD method much more efficient and
suffers from a smaller dispersion error, as shown in several
two-dimensional examples.},
Doi = {10.1109/LMWC.2004.837384},
Key = {8217810}
}
@article{fds283637,
Author = {Cheng, C and Liu, QH and Lee, JH and Massoud, HZ},
Title = {Spectral element method for the Schrödinger-Poisson
system},
Journal = {Journal of Computational Electronics},
Volume = {3},
Number = {3-4},
Pages = {417-421},
Publisher = {Springer Nature},
Year = {2004},
Month = {October},
url = {http://dx.doi.org/10.1007/s10825-004-7088-z},
Abstract = {A novel fast Spectral Element Method (SEM) with spectral
accuracy for the self-consistent solution of the
Schrödinger-Poisson system has been developed for the
simulation of semiconductor nanodevices. The field variables
in Schrödinger and Poisson equations are represented by
high-order Gauss-Lobatto-Legendre (GLL) polynomials, and the
stiffness and mass matrices of the system are obtained by
GLL quadrature to achieve spectral accuracy. A diagonal mass
matrix is obtained in the Schrödinger equation solver, and
a regular eigenvalue solver can be used to find the
eigenenergy. The predictor-corrector algorithm is applied to
further improve the efficiency. The SEM allows arbitrary
potential-energy and charge distributions. It can achieve
high accuracy with an extremely low sampling density, thus
significantly reducing the computer-memory requirements and
lowering the computational time in comparison with
conventional methods. Numerical results confirm the spectral
accuracy and significant efficiency of this method, and
indicate that the SEM is a highly efficient alternative
method for semiconductor nanodevice simulation. © Springer
Science + Business Media, Inc. 2004.},
Doi = {10.1007/s10825-004-7088-z},
Key = {fds283637}
}
@article{8142106,
Author = {Li, F and Liu, QH and Song, LP},
Title = {Three-dimensional reconstruction of objects buried in
layered media},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {1},
Pages = {193-196},
Publisher = {IEEE},
Address = {Monterey, CA, USA},
Year = {2004},
Month = {September},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/aps.2004.1329592},
Keywords = {buried object detection;electromagnetic wave scattering;fast
Fourier transforms;image reconstruction;inhomogeneous
media;inverse problems;iterative methods;},
Abstract = {Distorted Born iterative method (DBIM) and Born iterative
methods used for 3D image reconstruction of objects in
layered media and electromagnetic waves was discussed. BIM
and DBIM could obtain the location and size of the objects
even when the number of unknowns is larger than the number
of independent measurements. A computer code was developed
for objects completely embedded in one layer. It was
observed that the effect of the aperture on the inversion
showed λ/2 as a good spatial sampling density for
insufficient sources and receivers.},
Doi = {10.1109/aps.2004.1329592},
Key = {8142106}
}
@article{8142107,
Author = {Song, LP and Liu, QH and Li, F},
Title = {3D nonlinear electromagnetic inversion for buried objects in
layered media},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {1},
Pages = {197-200},
Publisher = {IEEE},
Address = {Monterey, CA, USA},
Year = {2004},
Month = {September},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/aps.2004.1329593},
Keywords = {buried object detection;electromagnetic wave
scattering;ground penetrating radar;inhomogeneous
media;inverse problems;multilayers;radar
imaging;},
Abstract = {The use of 3D nonlinear electromagnetic inversion for buried
objects in layered media was discussed. Such a half-space
background model appears acceptable for the inversion in the
case ∈ e3 = 5.0, namely, when there is a relatively low
dielectric contrast between middle layer and the lower
layer. It was found that the background model is important
to guarantee for the success of the inverse scattering
problem. The results show that the technique can effectively
accommodate to the case of multilayered media for surface
GPR survey.},
Doi = {10.1109/aps.2004.1329593},
Key = {8142107}
}
@article{fds319947,
Author = {Liu, J and Liu, QH},
Title = {A spectral integral method for periodic and nonperiodic
structures},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {4},
Pages = {3875-3878},
Publisher = {IEEE},
Year = {2004},
Month = {September},
url = {http://dx.doi.org/10.1109/aps.2004.1330195},
Abstract = {A spectral integral method for periodic and non periodic
structures by surface integral equation method was
discussed. The boundary integral equations outside and
inside the scatter for a dielectric object was presented.
The method was based on fast fourier transform (FFT)
algorithm and the subtraction of sigularities in Green's
fuctions. The method demonstrated high accuracy and reduced
computational cost and the method was extended to three
dimensions.},
Doi = {10.1109/aps.2004.1330195},
Key = {fds319947}
}
@article{fds283636,
Author = {Yan, QZ and Qing, HL and Zhao, G},
Title = {Multidomain pseudospectral time-domain (PSTD) method for
acoustic waves in lossy media},
Journal = {Journal of Computational Acoustics},
Volume = {12},
Number = {3},
Pages = {277-299},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {2004},
Month = {September},
url = {http://dx.doi.org/10.1142/S0218396X04002286},
Abstract = {A multidomain pseudospectral time-domain (PSTD) method is
developed for acoustic wave equations in lossy media. The
method is based on the spectral derivative operator
approximated by Chebyshev Lagrange polynomials. In this
multidomain scheme, the computational domain is decomposed
into a set of subdomains conformal to the problem geometry.
Each curved subdomain is then mapped onto a cube in the
curvilinear coordinates so that a tensor-product Chebyshev
grid can be utilized without the staircasing error. An
unsplit-field, well-posed PML is developed as the absorbing
boundary condition. The algorithm is validated by analytical
solutions. The numerical solutions show that this algorithm
is efficient for simulating acoustic wave phenomena in the
presence of complex objects in inhomogeneous media. To our
knowledge, the multidomain PSTD method for acoustics is a
new development in three dimensions, although in two
dimensions the method can be made equivalent to the
two-dimensional method in electromagnetics.},
Doi = {10.1142/S0218396X04002286},
Key = {fds283636}
}
@article{fds283635,
Author = {Liu, QH and Cheng, C and Massoud, HZ},
Title = {The spectral grid method: A novel fast Schrödinger-equation
solver for semiconductor nanodevice simulation},
Journal = {Ieee Transactions on Computer Aided Design of Integrated
Circuits and Systems},
Volume = {23},
Number = {8},
Pages = {1200-1208},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {August},
url = {http://dx.doi.org/10.1109/TCAD.2004.831592},
Abstract = {A spectral-domain method is described for solving
Schrödinger's equation based on the multidomain
pseudospectral method and boundary patching. The
computational domain is first divided into nonoverlapping
subdomains. Using the Chebyshev polynomials to represent the
unknown wave function in each subdomain, the spatial
derivatives are calculated with a spectral accuracy at the
Chebyshev collocation points. Boundary conditions at the
subdomain interfaces are then enforced to ensure the global
accuracy. Numerical results demonstrate that this
spectral-domain method has an exponential accuracy and is
flexible, and thus is an attractive method for large-scale
problems. With only about four cells per wavelength, the
results have an error less than 1 % in our typical examples.
For a typical quantum well, the method is about 51 and 295
times faster than the second-order finite-difference method
for 1% and 0.1 % accuracy, respectively. The spectral grid
method has also been validated by results obtained by the
finite-element method, semianalytical (Airy function)
method, and the Numerov's method.},
Doi = {10.1109/TCAD.2004.831592},
Key = {fds283635}
}
@article{fds283634,
Author = {Liu, QH and Zhao, G},
Title = {Review of PSTD methods for transient electromagnetics},
Journal = {International Journal of Numerical Modelling: Electronic
Networks, Devices and Fields},
Volume = {17},
Number = {3},
Pages = {299-323},
Publisher = {WILEY},
Year = {2004},
Month = {May},
url = {http://dx.doi.org/10.1002/jnm.544},
Abstract = {In this paper we review the recent development in
pseudospectral time-domain (PSTD) methods for broadband
electromagnetics. Starting from the basic ideas for
high-order approximation of spatial derivatives in periodic
and non-periodic domains, we will discuss the pseudospectral
time-domain methods for Maxwell's equations. Furthermore,
some recent time integration schemes for the PSTD methods
will be also presented. We will demonstrate these efficient
methods with some new results for large scale problems.
Copyright © 2004 John Wiley & Sons, Ltd.},
Doi = {10.1002/jnm.544},
Key = {fds283634}
}
@article{fds283633,
Author = {Li, F and Liu, QH and Song, LP},
Title = {Three-dimensional reconstruction of objects buried in
layered media using Born and distorted Born iterative
methods},
Journal = {Ieee Geoscience and Remote Sensing Letters},
Volume = {1},
Number = {2},
Pages = {107-111},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {April},
url = {http://dx.doi.org/10.1109/LGRS.2004.826562},
Abstract = {We develop electromagnetic inverse scattering methods to
reconstruct three-dimensional (3-D) objects buried in
layered media. The nonlinear inverse problem is solved
iteratively via the conjugate-gradient approach; within each
iteration, the problem is linearized by Born and distorted
Born approximations. The forward solution for layered media
is provided by the stabilized biconjugate-gradient fast
Fourier transform method. The inversion results from the
Born and distorted Born iterative methods are presented, and
the effects of the aperture size and noise on the inversion
results are also investigated. Numerical results show that
these methods are capable of reconstructing an arbitrary 3-D
inhomogeneous object buried in a multilayered medium with
high resolution.},
Doi = {10.1109/LGRS.2004.826562},
Key = {fds283633}
}
@article{fds283630,
Author = {Zhang, ZQ and Liu, QH},
Title = {Three-dimensional nonlinear image reconstruction for
microwave biomedical imaging.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {51},
Number = {3},
Pages = {544-548},
Year = {2004},
Month = {March},
ISSN = {0018-9294},
url = {http://www.ncbi.nlm.nih.gov/pubmed/15000387},
Abstract = {Active microwave imaging has attracted significant interests
in biomedical applications, in particular for breast
imaging. However, the high electrical contrasts in breast
tissue also increases the difficulty of forming an accurate
image because of the increased multiple scattering. To model
such strong three-dimensional (3-D) multiple scattering
effects in biomedical imaging applications, we develop a
full 3-D inverse scattering algorithm based on the
combination of the contrast source inversion and the fast
Fourier transform algorithm. Numerical results show that our
algorithm can accurately invert for the high-contrast media
in breast tissue.},
Doi = {10.1109/tbme.2003.821052},
Key = {fds283630}
}
@article{fds283631,
Author = {Zhao, G and Liu, QH},
Title = {The 3-D multidomain pseudospectral time-domain algorithm for
inhomogeneous conductive media},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {52},
Number = {3},
Pages = {742-749},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {March},
url = {http://dx.doi.org/10.1109/TAP.2004.825187},
Abstract = {A three-dimensional (3-D) multidomain pseudospectral
time-domain (PSTD) method with a strongly well-posed
perfectly matched layer (PML) is developed as an accurate
and flexible tool for the simulation of electromagnetic wave
propagation and scattering in inhomogeneous and conductive
media. This approach allows for an accurate treatment of
curved geometries by multidomain decomposition and
curvilinear coordinate transformation. Numerical experiments
show the results agree excellently with analytical solutions
and results of other well-known algorithms, and demonstrate
a remarkable improvement in accuracy and efficiency over the
FDTD method. The 3-D multidomain PSTD algorithm is then
applied to calculate radar cross sections
(RCS).},
Doi = {10.1109/TAP.2004.825187},
Key = {fds283631}
}
@article{fds283632,
Author = {Xiao, T and Liu, QH},
Title = {A staggered upwind embedded boundary (SUEB) method to
eliminate the FDTD staircasing error},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {52},
Number = {3},
Pages = {730-741},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {March},
url = {http://dx.doi.org/10.1109/TAP.2004.824675},
Abstract = {In spite of its flexibility and second-order accuracy in a
homogeneous medium, Yee's finite-difference time-domain
(FDTD) method suffers from serious degradation when treating
material interfaces, greatly reducing its accuracy in the
presence of inhomogeneous media and perfect conductors.
Indeed, such so-called staircasing approximation may lead to
local zeroth-order and global first-order errors. In this
work, an embedded FDTD scheme, the staggered upwind embedded
boundary (SUEB) method, is developed for the solution of
one- and two-dimensional Maxwell's equations. This simple
embedded technique uses upwind conditions in the FDTD method
to correctly represent the location and physical conditions
of material and metallic boundaries, hence eliminating
problems caused by the staircasing approximation. Accuracy
analysis has been made to show that the SUEB method
maintains a second-order accuracy globally. Since the entire
problem has been embedded into the simple staggered grid
similar to that employed by the Yee's scheme, extra effort
is only needed when treating the grid points close to the
interfaces. Therefore, little additional computational cost
is needed over Yee's scheme. The SUEB method has been
validated by analytical solutions for plane wave normally
incident to a planar boundary and for the TM wave
propagation in the presence of a dielectric cylinder and a
perfectly electrically conducting cylinder.},
Doi = {10.1109/TAP.2004.824675},
Key = {fds283632}
}
@article{8168824,
Author = {Liu, J and Liu, QH},
Title = {A Spectral Integral Method (SIM) for Periodic and
Nonperiodic Structures},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {14},
Number = {3},
Pages = {97-99},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Address = {Monterey, CA, USA},
Year = {2004},
Month = {March},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/LMWC.2004.824806},
Keywords = {computational electromagnetics;conducting bodies;dielectric
bodies;electromagnetic wave scattering;fast Fourier
transforms;Green's function methods;integral
equations;periodic structures;sampling methods;spectral
analysis;},
Abstract = {This letter presents a spectral integral method for
electromagnetic scattering from dielectric objects with
closed boundary. The method is developed for both periodic
and non-periodic structures. Numerical results demonstrate
the spectral accuracy of the method, and the advantages over
the method of moments.},
Doi = {10.1109/LMWC.2004.824806},
Key = {8168824}
}
@article{fds283627,
Author = {Wartenberg, SA and Liu, QH},
Title = {A Coaxial-to-Microstrip Transition for Multilayer
Substrates},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {52},
Number = {2},
Pages = {584-588},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {February},
url = {http://dx.doi.org/10.1109/TMTT.2003.821936},
Abstract = {Described is a right-angle coaxial-to-microstrip transition
suitable for multilayer substrates. Electrically, it
transforms the transmission mode from coaxial (TEM) to
microstrip (quasi-TEM). Physically, this transformation
occurs in two ways. First, strips of the ground plane are
incrementally removed from each metal layer. At the same
time, the coaxial line is gradually shifted off-center
(i.e., made eccentric) toward the microstrip line. The
theory supporting the technique is briefly discussed. To
demonstrate, a coaxial transition is designed on a
six-metal-layer laminate board. Measurements are compared to
a conventional coaxial transition design.},
Doi = {10.1109/TMTT.2003.821936},
Key = {fds283627}
}
@article{fds283628,
Author = {Millard, X and Liu, QH},
Title = {Simulation of Near-Surface Detection of Objects in Layered
Media by the BCGS-FFT Method},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {42},
Number = {2},
Pages = {327-334},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {February},
url = {http://dx.doi.org/10.1109/TGRS.2003.817799},
Abstract = {Near-surface electromagnetic characterization of objects
buried in multilayered earth is important for the detection
and identification of landmines, unexploded ordnance, and
underground structures. However, so far little progress has
been made in the development of fast algorithms for
inhomogeneous objects in a layered medium. We report an
iterative technique, the stabilized biconjugate gradient
fast Fourier transform (BCGS-FFT) method, that simulates
near-surface detection of three-dimensional, inhomogeneous
objects buried in multilayered media. The CPU time and
memory cost of the BCGS-FFT method is O(N log N) and O(N),
respectively, where N is the number of unknowns. This method
is significantly more efficient than method of moments
(MoM). It is capable of solving large-scale electromagnetic
scattering problems with an arbitrary inhomogeneous object
embedded in a layered medium with an arbitrary number of
layers. Examples in subsurface detection of large buried
objects are shown to demonstrate the efficacy of this
method. At present, the object must be located completely
within one single layer in this multilayer medium, but
efforts are underway to remove this limitation.},
Doi = {10.1109/TGRS.2003.817799},
Key = {fds283628}
}
@article{fds283629,
Author = {Fan, GX and Liu, QH},
Title = {Fast Fourier transform for discontinuous
functions},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {52},
Number = {2},
Pages = {461-465},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2004},
Month = {February},
url = {http://dx.doi.org/10.1109/TAP.2004.823965},
Abstract = {In computational electromagnetics and other areas of
computational science and engineering, Fourier transforms of
discontinuous functions are often required. We present a
fast algorithm for the evaluation of the Fourier transform
of piecewise smooth functions with uniformly or nonuniformly
sampled data by using a double interpolation procedure
combined with the fast Fourier transform (FFT) algorithm. We
call this the discontinuous FFT algorithm. For N sample
points, the complexity of the algorithm is O(νNp + νN log
(N)) where p is the interpolation order and ν is the
oversampling factor. The method also provides a new
nonuniform FFT algorithm for continuous functions. Numerical
experiments demonstrate the high efficiency and accuracy of
this discontinuous FFT algorithm.},
Doi = {10.1109/TAP.2004.823965},
Key = {fds283629}
}
@article{8161093,
Author = {Simsek, E. and Liu, Q.H.},
Title = {Fast computation of dyadic Green's function for layered
media and its application in interconnect
simulations},
Journal = {IEEE Antennas and Propagation Society Symposium (IEEE Cat.
No.04CH37529)},
Volume = {Vol.3},
Pages = {2783 Vol.3 -},
Address = {Monterey, CA, USA},
Year = {2004},
Keywords = {computational electromagnetics;electromagnetic field
theory;Green's function methods;inhomogeneous media;integral
equations;},
Abstract = {Summary form only given. In order to solve layered-medium
problems, such as interconnect simulations, various
numerical methods have been developed. We are concerned with
piecewise homogeneous objects embedded in a layered medium.
The surface integral equation (SIE) can be used to reduce
the number of unknowns required in the volume integral
equation. For the solution of the SIE, we first develop a
fast method to evaluate the Sommerfeld integrals in the
dyadic Green's function (GF) for a layered medium.
Particular attention is paid to evaluate the GF when the
source and observation points are on the same plane parallel
to the layer interfaces. The primary and quasi-static field
terms are subtracted from the integrand of the dyadic GF and
their contribution is calculated analytically. This makes
the integrand decay rapidly for large values of
k<sub>ρ</sub>. Since this is an exact method, the whole
procedure is robust; the results of this method have been
validated by comparison with many examples in the
literature, and the high efficiency has been verified. We
then apply this dyadic GF in the solution of surface
integral equations arising from interconnect
simulations},
Key = {8161093}
}
@article{8161148,
Author = {Chen, Y and Xie, Z and Shi, G and Joines, WT and Liu, QH and Carin,
L},
Title = {Time-domain target detection using a double-sided broadband
antenna},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {3},
Pages = {2999-3002},
Publisher = {IEEE},
Address = {Monterey, CA, USA},
Year = {2004},
ISSN = {1522-3965},
url = {http://dx.doi.org/10.1109/aps.2004.1332009},
Keywords = {antenna feeds;antenna radiation patterns;antenna
testing;broadband antennas;dipole antenna arrays;electric
fields;landmine detection;microwave antenna arrays;microwave
measurement;},
Abstract = {The application of a double-sided broadband antenna for
time-domain target detection was discussed. A mathematical
model to simulate the structure and performance of the
antenna was established, based on dipole antenna array
theory. A formula for the electric field was derived, and
the radiation patterns were calculated. It was found that
this antenna works well over a broad frequency range that is
50 MHz to 10.05 Ghz.},
Doi = {10.1109/aps.2004.1332009},
Key = {8161148}
}
@article{04098039448,
Author = {Chen, LF and Li, ZL and Liu, QH and Chen, S and Tang, Y and Zhong,
B},
Title = {Definition of component effective emissivity for
heterogeneous and non-isothermal surfaces and its
approximate calculation},
Journal = {International Journal of Remote Sensing},
Volume = {25},
Number = {1},
Pages = {231-244},
Publisher = {Informa UK Limited},
Year = {2004},
url = {http://dx.doi.org/10.1080/0143116031000116426},
Keywords = {Soils;Landforms;Surface properties;Thermodynamic
stability;Remote sensing;Monte Carlo methods;Computer
simulation;},
Abstract = {Measurement of land surface temperature faces many problems.
For example, each pixel over land surface is likely to be
heterogeneous and non-isothermal with both vegetation canopy
and background soil, and the three-dimensional structure of
canopy often makes the canopy radiation angular dependent.
It is difficult to define an overall land surface
temperature and emissivity at pixel scale for heterogeneous
and non-isothermal surfaces. After recalling several
definitions of effective emissivities, component effective
emissivity is defined in this paper under the conditions of
local thermal equilibrium and a constant material emissivity
for surface temperature variation in the normal Earth
environment. Component effective emissivities make it
possible to retrieve the component temperature based on
multi-directional measurements. The sum of component
effective emissivities is equal to the overall effective
emissivity, which can be used to inverse pixel-averaged
effective temperature. Taking the continuous plant/soil
system as an example, the Monte Carlo method is used to
simulate the effective emissivities, and an analytical
expression equation (AEE) of the effective emissivities
including direct-line emission and single scattering
contribution is developed. Monte Carlo simulated results
show that the sum of direct-line emission and single
scattering effective emissivity is close to overall
effective emissivity when soil and leaf are set to 0.94 and
0.98 respectively. Then component and overall effective
emissivities calculated by Monte Carlo method and AEE are
compared, and their differences are analysed for different
soil and leaf emissivities. It is shown that when soil and
leaf emissivities are set respectively to 0.94 and 0.98, the
differences are less than 0.006 within a 50° view zenith
angle. When soil or leaf emissivity is set to 0.9, the
difference reaches 0.025 or 0.016, which is large enough to
introduce a 1 K error in land surface temperature inversion
when this effective emissivity is used. The paper finally
proposes that the linear relationship of difference with
soil and leaf emissivity can be used to compensate the
errors.},
Doi = {10.1080/0143116031000116426},
Key = {04098039448}
}
@article{8354044,
Author = {Liu, QH and Hou, JX and Xiao, YP and Li, LX},
Title = {Quantum motion on 2D surface of nonspherical
topology},
Journal = {Int. J. Theor. Phys. (Usa)},
Volume = {43},
Number = {4},
Pages = {1011-1017},
Publisher = {Springer Science and Business Media LLC},
Year = {2004},
url = {http://dx.doi.org/10.1023/B:IJTP.0000048598.17929.02},
Keywords = {functional analysis;quantum theory;topology;},
Abstract = {An excess term exists when using Hermitian form of Cartesian
momentum pi(i=1,2,3) in usual kinetic energy
1/(2μ)Σpi2 for a particle moving on the 2D surface,
and the correct kinetic energy turns to be
1/(2μ)Σ1/fipifipi where the fi are dummy factors in
classical mechanics and nontrivial in quantum mechanics. In
this paper, the explicit form of the dummy functions fi is
given for some surfaces of nonspherical topology, such as
toroidal surface, paraboloid of revolution, the hyperboloid
of revolution of two sheets, and the hyperboloid of
revolution of one sheets},
Doi = {10.1023/B:IJTP.0000048598.17929.02},
Key = {8354044}
}
@article{8338828,
Author = {Zeng, YQ and Liu, QH},
Title = {A multidomain PSTD method for 3D elastic wave
equations},
Journal = {Bull. Seismol. Soc. Am. (Usa)},
Volume = {94},
Number = {3},
Pages = {1002-1015},
Publisher = {Seismological Society of America (SSA)},
Year = {2004},
url = {http://dx.doi.org/10.1785/0120030103},
Keywords = {Chebyshev approximation;elastic waves;finite difference
time-domain analysis;time-domain analysis;wave
equations;},
Abstract = {A 3D multidomain pseudospectral time-domain method is
developed for elastic wave equations. The method is based on
the spectral derivative operator approximated by Chebyshev
or Lagrange polynomials. Unlike the Fourier method that
assumes periodic boundary conditions, the Chebyshev
pseudospectral method allows for the incorporation of
various boundary conditions (such as the free surface
boundary condition) into the numerical scheme. In this
multidomain scheme, the computational domain is decomposed
into a set of subdomains conformal to the problem geometry.
Each curved subdomain is then mapped onto a cube in the
curvilinear coordinates so that a tensor-product Chebyshev
grid can be utilized without the staircasing error. An
unsplit-field perfectly matched layer is developed as the
absorbing boundary condition. Numerical examples show that
this scheme is efficient for simulating elastic waves
phenomena in the presence of complex objects. The method is
found to be significantly more efficient than the
finite-difference time-domain method in terms of memory and
run-time requirements},
Doi = {10.1785/0120030103},
Key = {8338828}
}
@article{fds283825,
Author = {Fan, GX and Liu, QH},
Title = {A strongly well-posed PML in Lossy media},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {2},
Pages = {97-100},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {December},
url = {http://dx.doi.org/10.1109/LAWP.2003.814776},
Abstract = {A systematic method is presented for formulating strongly
well-posed perfectly matched layer (PML) for lossy media.
This method is based on the complex coordinate-stretching
technique that was originally proposed for split-field PML
in lossy media. However, unlike the previous split-field
PML, this iinsplit-field PML retains the hyperbolic system
in Maxwell's equations, with some additional terms that are
governed by ordinary differential equations that do not
affect the well-posedness of the system. The derivation of
the PML formulation is rigorous and straightforward.},
Doi = {10.1109/LAWP.2003.814776},
Key = {fds283825}
}
@article{7790256,
Author = {Zhao, G and Liu, QH},
Title = {The Unconditionally Stable Pseudospectral Time-Domain (PSTD)
Method},
Journal = {Ieee Microwave and Wireless Components Letters},
Volume = {13},
Number = {11},
Pages = {475-477},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {November},
url = {http://dx.doi.org/10.1109/LMWC.2003.819372},
Keywords = {finite difference time-domain analysis;Maxwell
equations;numerical stability;},
Abstract = {This letter presents a new time-domain method for Maxwell's
equations, in which the unconditionally stable techniques,
the alternating direction implicit (ADI) and the split-step
(SS) schemes, are developed for the pseudospectral
time-domain (PSTD) algorithm to maintain stability while
achieving higher accuracy and efficiency over the FDTD
method. The multidomain strategy is employed to allow for a
flexible treatment of internal inhomogeneities. Numerical
results demonstrate the unconditional stability and the
second-order accuracy for both ADI- and SS-PSTD
algorithms.},
Doi = {10.1109/LMWC.2003.819372},
Key = {7790256}
}
@article{fds283774,
Author = {Zhang, ZQ and Liu, QH and Xiao, C and Ward, E and Ybarra, G and Joines,
WT},
Title = {Microwave breast imaging: 3-D forward scattering
simulation.},
Journal = {Ieee Transactions on Bio Medical Engineering},
Volume = {50},
Number = {10},
Pages = {1180-1189},
Year = {2003},
Month = {October},
ISSN = {0018-9294},
url = {http://www.ncbi.nlm.nih.gov/pubmed/14560772},
Abstract = {Active microwave imaging (MWI) is emerging as a promising
technique for the detection of biomedical anomalies such as
breast cancer because of the high electrical contrasts
between malignant tumors and normal tissue. Previously, we
have developed fast two-dimensional forward and inverse
scattering algorithms for MWI systems. In this paper, we
report the full three-dimensional (3-D) forward scattering
simulation in order to account for 3-D effects and to
provide a fast solver in future 3-D nonlinear inverse
scattering methods. The 3-D fast forward method is based on
the stabilized biconjugate-gradient fast Fourier transform
(BCGS-FFT) algorithm. The method has been validated for
various MWI measurement scenarios. Using this fast
simulation method, we demonstrate the importance of
accounting for 3-D effects in MWI, and we compare numerical
results with the measurements from an experimental
prototype.},
Doi = {10.1109/TBME.2003.817634},
Key = {fds283774}
}
@article{fds283615,
Author = {Zhao, G and Liu, QH},
Title = {The 3-D multidomain pseudospectral time-domain algorithm for
inhomogeneous conductive media},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {3},
Pages = {559-562},
Year = {2003},
Month = {September},
Abstract = {A three-dimensional multidomain pseudospectral time-domain
algorithm was developed to model electromagnetic scattering
by introducing inhomogeneous objects as well as perfect
conductors. The numerical results were validated by
analytical soluitions and the FDTD method.},
Key = {fds283615}
}
@article{fds283616,
Author = {Xiao, T and Liu, QH},
Title = {A staggered time integration technique for spectral
methods},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {2},
Pages = {1124-1127},
Year = {2003},
Month = {September},
Abstract = {A staggered-time integrator is introduced in the spectral
methods to further improve their computational efficiency.
Case studies of the radiation of an electric dipole source
in a cylinder validate the technique. Applications in the
modeling of photonic bandgap materials are shown to confirm
the efficacy of the method.},
Key = {fds283616}
}
@article{fds283620,
Author = {Millard, X and Liu, QH},
Title = {A Fast Volume Integral Equation Solver for Electromagnetic
Scattering from Large Inhomogeneous Objects in Planarly
Layered Media},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {51},
Number = {9},
Pages = {2393-2401},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {September},
url = {http://dx.doi.org/10.1109/TAP.2003.816311},
Abstract = {A newly developed iterative method, the stabilized
biconjugate gradient fast Fourier transform (BCGS-FFT)
method is applied to simulate electromagnetic scattering
from large inhomogeneous objects embedded in a planarly
layered medium. In this fast solver, the weak-form
formulation is applied to obtain a less singular
discretization of the volume electric field integral
equation. Several techniques are utilized to speed up the
dyadic Green's function evaluation. To accelerate the
operation of the dyadic Green's function on an induced
current (i.e., the "Green's operation"), the Green's
function is split into convolutional and correlational
components so that FFT can be applied. The CPU time and
memory cost of this BCGS-FFT method is O( N log N) and O(N),
respectively, where N is the number of unknowns,
significantly more efficient than the method of moments
(MoM). As a result, this method is capable of solving
large-scale electromagnetic scattering problems in a
planarly layered background. A large-scale scattering
problem in a layered medium with more than three million
unknowns has been solved on a Sun Ultra 60 workstation with
1.2 GBytes memory.},
Doi = {10.1109/TAP.2003.816311},
Key = {fds283620}
}
@article{fds283823,
Author = {Xiao, T and Liu, QH},
Title = {Unstructured-grid spectral method for 3D maxwell's equations
with well-posed PML},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {694-697},
Year = {2003},
Month = {September},
Abstract = {A spectral penalty method for the solution of 3D maxwell's
equations with well-posed perfectly matched layer (PML) was
developed to model the electromagnetic waves in unbounded
physical region. Numerical results of the radiation of an
electric dipole source located at a sphere center showed an
excellent agreement with analytical solution. As such, the
well-posed PML can be successfully introduced into the
spectral penalty methods and was found to work very well in
absorbing outgoing waves.},
Key = {fds283823}
}
@article{fds283824,
Author = {Zhao, G and Liu, QH},
Title = {Unconditionally stable multidomain pseudospectral
time-domain (PSTD) method},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {4},
Pages = {336-339},
Year = {2003},
Month = {September},
Abstract = {The multidomain Alternating Direct Implicit and Split-Step
PSTD algorithms are proposed and implemented. As such, their
unconditional stability is numerically demonstrated. The
simulation results are validated by analytical solutions,
and indicate the second-order accuracy.},
Key = {fds283824}
}
@article{fds283617,
Author = {Xiao, T and Liu, QH},
Title = {Finite difference computation of head-related transfer
function for human hearing.},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {113},
Number = {5},
Pages = {2434-2441},
Year = {2003},
Month = {May},
ISSN = {0001-4966},
url = {http://www.ncbi.nlm.nih.gov/pubmed/12765362},
Abstract = {Modeling the head-related transfer function (HRTF) is a key
to many applications in spatial audio. To understand and
predict the effects of head geometry and the surrounding
environment on the HRTF, a three-dimensional
finite-difference time domain model (3D FDTD) has been
developed to simulate acoustic wave interaction with a human
head. A perfectly matched layer (PML) is used to absorb
outgoing waves at the truncated boundary of an unbounded
medium. An external source is utilized to reduce the
computational domain size through the scattered-field/total-field
formulation. This numerical model has been validated by
analytical solutions for a spherical head model. The 3D FDTD
code is then used as a computational tool to predict the
HRTF for various scenarios. In particular, a simplified
spherical head model is compared to a realistic head model
up to about 7 kHz. The HRTF is also computed for a realistic
head model in the presence of a wall. It is demonstrated
that this 3D FDTD model can be a useful tool for spatial
audio applications.},
Doi = {10.1121/1.1561495},
Key = {fds283617}
}
@article{fds283618,
Author = {Zhang, ZQ and Liu, QH},
Title = {Applications of the BCGS-FFT method to 3-D induction well
logging problems},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {41},
Number = {5 PART 1},
Pages = {998-1004},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {May},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2003.811547},
Abstract = {Electromagnetic induction logging is one of the most
important measurements in borehole characterization of an
oil reservoir. With the ever increasing number of deviated
and horizontal wells aiming for improved hydrocarbon
production, simulation of induction well logging in
realistic three-dimensional (3-D) environments has become an
important subject of research. In this paper, we investigate
a fast spectral-domain solver for the second-kind integral
equation arising from Maxwell's equations for 3-D induction
logging. We combine an iterative stabilized
biconjugate-gradient (BiCGSTAB) technique with a fast
Fourier transform (FFT) algorithm (BCGS-FFT method) to
compute electromagnetic fields in 3-D inhomogeneous media at
induction frequencies. The electric field integral equation
is discretized through the use of the magnetic vector
potential to weaken the singularity associated with the
dyadic Green's function. The computational time and computer
memory requirements of this BCGS-FFT method are O(N log N)
and O(N), respectively, where N is the total number of
unknowns. © 2003 IEEE.},
Doi = {10.1109/TGRS.2003.811547},
Key = {fds283618}
}
@article{fds283828,
Author = {Tang, Z and Liu, QH},
Title = {The 2.5D FDTD and Fourier PSTD methods and
applications},
Journal = {Microwave and Optical Technology Letters},
Volume = {36},
Number = {6},
Pages = {430-436},
Publisher = {WILEY},
Year = {2003},
Month = {March},
url = {http://dx.doi.org/10.1002/mop.10783},
Abstract = {In this work, 2.5-dimensional finite-difference time-domain
(FOTD) and pseudospectral time-domain (PSTD) algorithms are
developed for electromagnetic waves in media that are
invariant in one spatial dimension. Both algorithms use
Berenger's perfect matched layer (PML) as an absorbing
boundary condition. The FDTD method is an extension of Yee's
3D algorithm to 2.5D. The PSTD algorithm uses the fast
Fourier transform to approximate spatial derivatives, and
gives a much higher accuracy than the FDTD method. Numerical
results have been validated by comparing them with
analytical solutions. The methods have been applied to
ground-penetrating-radar and dielectric-waveguide problems.
© 2003 Wiley Periodicals, Inc.},
Doi = {10.1002/mop.10783},
Key = {fds283828}
}
@article{fds283826,
Author = {Zhang, ZQ and Liu, QH and Xu, XM},
Title = {RCS computation of large inhomogeneous objects using a fast
integral equation solver},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {51},
Number = {3},
Pages = {613-618},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {March},
url = {http://dx.doi.org/10.1109/TAP.2003.808536},
Abstract = {In this paper, we apply a fast Fourier transform (FFT)
accelerated volume Integral equation solver to compute the
radar cross section of large-scale inhomogeneous objects.
This method is related to Bojarski's k-space method and the
subsequent conjugate-(CG) and biconjugate-gradient (BCG) FFT
algorithms. The method developed here combines the weak-form
discretization with the BCG and stabilized BCG (BCGS)
solvers. We show that this method has marked improvements
over related algorithms. The numerical method has been
validated by Mie series for multilayer spheres and applied
to some practical problems. With this method we are
currently able to solve a three-dimensional problem with a
volume of size 3648λ3 (21.23 million unknowns) on a single
workstation.},
Doi = {10.1109/TAP.2003.808536},
Key = {fds283826}
}
@article{fds283827,
Author = {Zhao, G and Liu, QH},
Title = {The 2.5-D multidomain pseudospectral time-domain
algorithm},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {51},
Number = {3},
Pages = {619-627},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {March},
url = {http://dx.doi.org/10.1109/TAP.2003.809852},
Abstract = {A 2.5-D multidomain pseudospectral time-domain (PSTD) method
with a suitable well-posed perfectly matched layer is
developed as an accurate and flexible tool for the
simulation of electromagnetic wave propagation and
scattering in conductive and inhomogeneous media. This
approach allows for an accurate treatment of curved
geometries with a high efficiency. Numerical results show an
excellent agreement with analytical solutions for lossy
dielectric cylinders. The 2.5-D multidomain PSTD algorithm
is applied to several scattering and waveguiding
problems.},
Doi = {10.1109/TAP.2003.809852},
Key = {fds283827}
}
@article{fds283619,
Author = {Liu, QH and Sinha, BK},
Title = {A 3D cylindrical PML/FDTD method for elastic waves in
fluid-filled pressurized boreholes in triaxially stressed
formations},
Journal = {Geophysics},
Volume = {68},
Number = {5},
Pages = {1731-1743},
Publisher = {Society of Exploration Geophysicists},
Year = {2003},
Month = {January},
url = {http://dx.doi.org/10.1190/1.1620646},
Abstract = {A new 3D cylindrical perfectly matched layer (PML)
formulation is developed for elastic wave propagation in a
pressurized borehole surrounded by a triaxially stressed
solid formation. The linear elastic formation is altered by
overburden and tectonic stresses that cause significant
changes in the wave propagation characteristics in a
borehole. The 3D cylindrical problem with both radial and
azimuthal heterogeneities is suitable for numerical
solutions of the wave equations by finite-difference
time-domain (FDTD) and pseudospectral time-domain (PSTD)
methods. Compared to the previous 2.5D formulation with
other absorbing boundary conditions, this 3D cylindrical PML
formulation allows modeling of a borehole-conformal, full 3D
description of borehole elastic waves in a stress-induced
heterogeneous formation. We have developed an FDTD method
using this PML as an absorbing boundary condition. In
addition to the ability to solve full 3D problems, this
method is found to be advantageous over the previously
reported 2.5D finite-difference formulation because a
borehole can now be adequately simulated with fewer grid
points. Results from the new FDTD technique confirm the
principle of superposition of the influence of various
stress components on both the borehole monopole and dipole
dispersions. In addition, we confirm that the increase in
shear-wave velocity caused by a uniaxial stress applied in
the propagation direction is the same as that applied
parallel to the radial polarization direction.},
Doi = {10.1190/1.1620646},
Key = {fds283619}
}
@article{fds283822,
Author = {Deshmukh, I and Liu, QH},
Title = {Pseudospectral beam-propagation method for optical
waveguides},
Journal = {Ieee Photonics Technology Letters},
Volume = {15},
Number = {1},
Pages = {60-62},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
Month = {January},
url = {http://dx.doi.org/10.1109/LPT.2002.805797},
Abstract = {We propose a wide-angle pseudospectral beam-propagation
method using Padé approximant operator for strongly guiding
and longitudinally varying optical waveguides. We validate
the numerical results of our method by comparison against
results obtained from a robust and widely used
finite-element beam-propagation method.},
Doi = {10.1109/LPT.2002.805797},
Key = {fds283822}
}
@article{7632723,
Author = {Zhao, G and Zeng, YQ and Liu, QH},
Title = {The 3-D multidomain pseudospectral time-domain method for
wideband simulation},
Journal = {Ieee Microw. Wirel. Compon. Lett. (Usa)},
Volume = {13},
Number = {5},
Pages = {184-186},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2003},
url = {http://dx.doi.org/10.1109/LMWC.2003.811667},
Keywords = {Chebyshev approximation;computational electromagnetics;conducting
materials;inhomogeneous media;interpolation;matrix
algebra;Maxwell equations;polynomials;simulation;time-domain
analysis;},
Abstract = {A three-dimensional (3-D) multidomain pseudospectral
time-domain (PSTD) method with a well-posed PML is developed
as an accurate and efficient solver for Maxwell's equations
in conductive and inhomogeneous media. The curved object is
accurately treated by curvilinear coordinate transformation.
Spatial derivatives are obtained by the Chebyshev
collocation method to achieve a high-order accuracy.
Numerical results show an excellent agreement with solutions
obtained by the FDTD method under fine sampling},
Doi = {10.1109/LMWC.2003.811667},
Key = {7632723}
}
@article{fds283613,
Author = {Sinha, BK and Liu, QH},
Title = {Acoustic waves in pressurized boreholes in formations with
triaxial stresses},
Journal = {Proceedings Ieee Ultrasonics Symposium},
Volume = {1},
Pages = {505-510},
Year = {2002},
Month = {December},
Abstract = {A finite-difference formulation of equations of motion for
elastic waves in prestressed formations has been used to
calculate synthetic waveforms at an array of receivers in a
liquid-filled borehole. Equations of motion for elastic
waves in prestressed materials are derived from rotationally
invariant equations of nonlinear elasticity. These equations
describe the influence of borehole hydrostatic (mud)
pressure as well as formation stresses on acoustic waves
produced by either a monopole or dipole transmitter placed
on the borehole axis. The synthetic waveforms are processed
by a modified matrix pencil algorithm for isolating both
dispersive and non-dispersive arrivals in the wavetrain.
Computational results show that a difference in the maximum
and minimum horizontal stresses causes dipole dispersion
crossovers that can be used as an indicator of
stress-induced anisotropy dominating the data. On the other
hand, an increase in the overburden stress causes both the
Stoneley and dipole dispersions to shift toward higher
velocities by varying amounts at various frequencies. Any
increase in the mud pressure introduces an altered annulus
surrounding the borehole surface. This annulus exhibits
radial variations in the near-wellbore radial and hoop
stresses. Both the Stoneley and dipole dispersions show
increasing velocities at higher frequencies. Changes in
borehole acoustic wave velocities caused by a change in any
one of the formation principal stresses yield
frequency-dependent overburden, maximum horizontal, and
minimum horizontal stress coefficients of velocities. These
stress coefficients of velocities can be used to invert
measured changes in borehole dispersions at various depths
for corresponding changes in formation stresses.},
Key = {fds283613}
}
@article{fds283614,
Author = {Zhang, ZQ and Liu, QH},
Title = {A Volume Adaptive Integral Method (VAIM) for 3-D
inhomogeneous objects},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {1},
Pages = {102-105},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2002},
Month = {December},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2002.805126},
Abstract = {This letter describes a volume adaptive integral method
(VAIM) for electromagnetic scattering from three-dimensional
(3-D) inhomogeneous objects. By projecting the unknown
current density within an arbitrary element in the
inhomogeneous object onto a fictitious uniform grid, this
method calculates the far-zone interactions of basis and
testing functions through the fast Fourier transform, thus
greatly reducing the memory requirement to O(N) and CPU
requirement to O(N log N), where N is the number of
unknowns. The numerical results have been validated by the
method of moment. © 2002 IEEE.},
Doi = {10.1109/LAWP.2002.805126},
Key = {fds283614}
}
@article{7633608,
Author = {Liu, QH},
Title = {A pseudospectral frequency-domain (PSFD) method for
computational electromagnetics},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {1},
Number = {1},
Pages = {131-134},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2002},
Month = {December},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2002.806755},
Keywords = {computational electromagnetics;frequency-domain
analysis;Maxwell equations;spectral analysis;},
Abstract = {This letter describes a new frequency-domain method for
Maxwell's equations based on the multidomain pseudospectral
method. The computational domain is first divided into
nonoverlapping subdomains. Using the Chebyshev polynomials
to represent the unknown field components in each subdomain,
the spatial derivatives are calculated with a spectral
accuracy at the Chebyshev collocation points. The physical
boundary conditions at the subdomain interfaces are enforced
to ensure the global accuracy. Numerical results demonstrate
that the pseudospectral frequency-domain (PSFD) method has a
spectral accuracy, and thus is an attractive method for
large-scale problems. With only about five cells per
wavelength, the results have an error less than 1% in our
typical examples. © 2002 IEEE.},
Doi = {10.1109/LAWP.2002.806755},
Key = {7633608}
}
@article{7633593,
Author = {Xu, XM and Liu, QH},
Title = {The BCGS-FFT method for electromagnetic scattering from
inhomogeneous objects in a planarly layered
medium},
Journal = {Ieee Antennas and Wireless Propagation Letters},
Volume = {1},
Number = {1},
Pages = {77-80},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2002},
Month = {December},
ISSN = {1536-1225},
url = {http://dx.doi.org/10.1109/LAWP.2002.802549},
Keywords = {conjugate gradient methods;electromagnetic wave
scattering;fast Fourier transforms;inhomogeneous
media;iterative methods;},
Abstract = {An iterative method, the stabilized biconjugate gradient
fast Fourier transform (BCGS-FFT) method, combined with the
FFT is developed for solving electromagnetic (EM) scattering
from inhomogeneous objects embedded in a planarly layered
medium. The CPU time and memory cost of this BCGS-FFT method
is O(N log N) and O(N), respectively, significantly more
efficient than both direct and iterative solutions of the
method of moment. As a result, this method is capable of
solving large-scale EM scattering problems in a planarly
layered background. © 2002 IEEE.},
Doi = {10.1109/LAWP.2002.802549},
Key = {7633593}
}
@article{fds283610,
Author = {Zhao, G and Liu, QH},
Title = {Applications of the 2.5-D multidomain pseudospectral
time-domain algorithm},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {3},
Pages = {236-239},
Year = {2002},
Month = {August},
Abstract = {A two-and-a-half dimensional multidomain pseudospectral
time-domain algorithm to model electromagnetic scattering by
lossy inhomogeneous objects as well as perfect conductors
was made. As such, a 2.5-D well-posed perfectly matched
layer (PML) was used to absorb outgoing waves at the
truncated boundary of an unbounded medium in the algorithm.
As a result, the numerical results show an excellent
agreement with an-alytical solutions.},
Key = {fds283610}
}
@article{fds283611,
Author = {Xu, X and Liu, QH and Zhang, ZQ},
Title = {The stabilized biconjugate gradient fast Fourier transform
method for electromagnetic scattering},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {2},
Pages = {614-617},
Year = {2002},
Month = {August},
Abstract = {An iterative method, the stabilized biconjugate gradient
(BiCGSTAB) method, combined with the fast Fourier transform
(FFT) for solving electromagnetic scattering problems is
developed for 3-D volume electric field integral equation.
It converges significantly faster than the conventional
conjugate gradient (CG) and biconjugate gradient (BiCG) fast
Fourier transform methods. With this BCGS-FFT method, we can
solve a large-scale volume integral equation with 20 million
unknowns on a single CPU workstation.},
Key = {fds283611}
}
@article{fds283612,
Author = {Zhang, ZQ and Liu, QH},
Title = {Applications of microwave imaging to three-dimensional
biological tissues},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {1},
Pages = {831-834},
Year = {2002},
Month = {August},
Abstract = {Nonlinear inverse scattering methods were applied to
simulate three-dimensional microwave imaging for breast
tumor detection. Numerical results demonstrate the
efficiency of the inverse method, and the high-resolution of
the image formation algorithm for the breast imaging
applications.},
Key = {fds283612}
}
@article{fds283820,
Author = {Fan, GX and Liu, QH and Hesthaven, JS},
Title = {Multidomain pseudospectral time-domain simulations of
scattering by objects buried in lossy media},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {40},
Number = {6},
Pages = {1366-1373},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2002},
Month = {June},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/TGRS.2002.800272},
Abstract = {A multidomain pseudospectral time-domain (PSTD) method with
a newly developed well-posed PML is introduced as an
accurate and flexible tool for the modeling of
electromagnetic scattering by 2-D objects buried in an
inhomogeneous lossy medium. Compared with the previous
single-domain Fourier PSTD method, this approach allows for
an accurate treatment of curved geometries with subdomains,
curvilinear mapping, and high-order Chebyshev polynomials.
The effectiveness of the algorithm is confirmed by an
excellent agreement between the numerical results and
analytical solutions for perfectly conducting as well as
permeable dielectric cylinders. The algorithm has been
applied to model various ground-penetrating radar (GPR)
applications involving curved objects in a lossy half space
with an undulating surface. This multidomain PSTD algorithm
is potentially a very useful tool for simulating antennas
near complex objects and inhomogeneous media.},
Doi = {10.1109/TGRS.2002.800272},
Key = {fds283820}
}
@article{fds283819,
Author = {Xu, XM and Liu, QH and Zhang, ZQ},
Title = {The Stabilized Biconjugate Gradient Fast Fourier Transform
Method for Electromagnetic Scattering},
Journal = {Applied Computational Electromagnetics Society
Newsletter},
Volume = {17},
Number = {1},
Pages = {97-103},
Year = {2002},
Month = {March},
Abstract = {An iterative method, the stabilized biconjugate gradient
(BiCGSTAB) method, combined with the fast Fourier transform
(FFT) for solving electromagnetic scattering problems is
developed for the 3-D volume electric field integral
equation. It converges significantly faster than the
conventional conjugate gradient (CG) and biconjugate
gradient (BiCG) fast Fourier transform methods. With this
BCGS-FFT method, we can solve a large-scale volume integral
equation with 20 million unknowns on a single CPU
workstation.},
Key = {fds283819}
}
@article{fds283821,
Author = {Fan, GX and Liu, QH},
Title = {Dyadic Green's functions for curved waveguides and cavities
and their reformulation},
Journal = {Radio Science},
Volume = {37},
Number = {5},
Pages = {11-1-11-10},
Publisher = {American Geophysical Union (AGU)},
Year = {2002},
Month = {January},
url = {http://dx.doi.org/10.1029/2001rs002476},
Abstract = {Dyadic Green's functions (DGFs) for continuously curved
waveguides are important for the feeding and radiation
problems of cylindrically conformal slotted-waveguide
arrays. The major difficulty in the construction of these
DGFs in curved waveguides and cavities is that there are no
entire-domain TE or TM modes with respect to the curving
direction, while the longitudinal-section electric (LSE) and
magnetic (LSM) modes do not have the complete orthogonality
in terms of the dot product as required by the conventional
Ohm-Rayleigh method as practiced in literature. Therefore,
the conventional Ohm-Rayleigh method for constructing DGFs
is not applicable to curved waveguides. In this work, the
DGFs are constructed with the help of the Lorentz
reciprocity theorem and the mode orthogonality based on the
concept of power flow, and by adding the source singularity
terms. To reduce the orders of singularity of DGFs in their
application to waveguide walls, the common form of DGFs is
then reformulated into a form convenient for numerical
computation by both forward and backward derivation
procedures. Finally, a general procedure is proposed for the
reformulation of DGFs for common types of waveguides. The
DGFs derived are applicable to problems with curved
waveguide junctions, and coupling and radiating slots for
conformal slotted-waveguide antennas.},
Doi = {10.1029/2001rs002476},
Key = {fds283821}
}
@article{7522929,
Author = {Sha, L and Nolte, LW and Zhang, ZQ and Liu, QH},
Title = {Performance analysis for Bayesian microwave imaging in
decision aided breast tumor diagnosis},
Journal = {Proceedings International Symposium on Biomedical
Imaging},
Volume = {2002-January},
Pages = {1039-1042},
Publisher = {IEEE},
Address = {Washington, DC, USA},
Year = {2002},
Month = {January},
ISBN = {078037584X},
url = {http://dx.doi.org/10.1109/ISBI.2002.1029442},
Keywords = {Bayes methods;bioelectric phenomena;biological
organs;biomedical imaging;decision support systems;image
reconstruction;mammography;Markov processes;medical image
processing;medical signal detection;microwave
imaging;microwave propagation;permittivity;tumours;},
Abstract = {In this paper the Markov Random Field is used to model the
breast permittivity cross section as a propagating medium,
and incorporate it into the forward Electromagnetic (EM)
propagation to predict the random field of the EM
measurements at a received array of sensors. Given these EM
field measurements, Bayesian approaches are then developed
to compute the likelihood ratio for tumor detection and the
a posteriori probability display of tumor localization.
Quantitative performance evaluations using simulations
demonstrate the advantage of using the Bayesian approach to
directly process the measurement data as compared to using
the Bayesian or threshold approaches to detect and localize
the tumor based on the reconstructed permittivity
image.},
Doi = {10.1109/ISBI.2002.1029442},
Key = {7522929}
}
@article{fds283773,
Author = {Liu, QH and Zhang, ZQ and Wang, TT and Bryan, JA and Ybarra, GA and Nolte,
LW and Joines, WT},
Title = {Active microwave imaging I - 2-D forward and inverse
scattering methods},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {50},
Number = {1 I},
Pages = {123-133},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2002},
ISSN = {0018-9480},
url = {http://dx.doi.org/10.1109/22.981256},
Abstract = {Active microwave imaging (MWI) for the detection of breast
tumors is an emerging technique to complement existing X-ray
mammography. The potential advantages of MWI arise mainly
from the high contrast of electrical properties between
tumors and normal breast tissue. However, this high contrast
also increases the difficulty of forming an accurate image
because of increased multiple scattering. To address this
issue, we develop fast forward methods based on the
combination of the extended Born approximation, conjugate-
and biconjugate-gradient methods, and the fast Fourier
transform. We propose two nonlinear MWI algorithms to
improve the resolution for the high-contrast media
encountered in microwave breast-tumor detection. Numerical
results Show that our algorithms can accurately model and
invert for the high-contrast media in breast tissue. The
outcome of the inversion algorithms is a high-resolution
digital image containing the physical properties of the
tissue and potential tumors.},
Doi = {10.1109/22.981256},
Key = {fds283773}
}
@article{fds283609,
Author = {Xu, XM and Liu, QH},
Title = {Fast electromagnetic modeling for electronic packaging in
layered media},
Journal = {Ieee Topical Meeting on Electrical Performance of Electronic
Packaging},
Pages = {181-184},
Year = {2001},
Month = {December},
Abstract = {A fast numerical method, the stabilized biconjugate gradient
fast Fourier transform method (BCGS-FFT), is applied to
solve the electric field integral equation (EFIE). The EFIE
characterizes the electromagnetic behavior of printed
conductors in a planarly layered medium. This method is
applied to characterize high-speed electronic
packages.},
Key = {fds283609}
}
@article{01486744757,
Author = {Liu, QH and He, JQ},
Title = {An efficient PSTD algorithm for cylindrical
coordinates},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {49},
Number = {9},
Pages = {1349-1351},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2001},
Month = {September},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/8.947028},
Keywords = {Electromagnetic wave scattering;Algorithms;Time domain
analysis;Spectrum analysis;Maxwell equations;Fast Fourier
transforms;Mathematical models;},
Abstract = {A pseudospectral time-domain (PSTD) algorithm is developed
to overcome limitations in the conventional solution methods
for Maxwell's equations in cylindrical coordinates. It is
based on the fast Fourier transform (FFT) representation of
spatial derivatives and a centered grid. The main
contributions of this algorithm are to eliminate the
singularity problem at the axis and to allow a larger time
step. It uses a coarse grid close to the Nyquist sampling
density provided that the geometrical modeling does not
require fine cells. It reduces the required number of
unknowns and the number of time steps in the
finite-difference time-domain (FDTD) method and is efficient
for large-scale problems.},
Doi = {10.1109/8.947028},
Key = {01486744757}
}
@article{6942592,
Author = {Fan, GX and Liu, QH},
Title = {Pseudospectral time-domain algorithm applied to
electromagnetic scattering from electrically large
objects},
Journal = {Microwave and Optical Technology Letters},
Volume = {29},
Number = {2},
Pages = {123-125},
Publisher = {WILEY},
Year = {2001},
Month = {April},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.1103},
Keywords = {electromagnetic wave scattering;spectral-domain
analysis;time-domain analysis;},
Abstract = {The pseudospectral time-domain (PSTD) algorithm is extended
to model the electromagnetic scattering from both 2-D and
3-D objects. The plane-wave excitation and the time-domain
near-far feld transforms in the stretched coordinates are
efficiently incorporated into the scattered-field PSTD
algorithm. Numerical results demonstrate the effectiveness
of the algorithm in wave-scattering problems. © 2001 John
Wiley & Sons, Inc.},
Doi = {10.1002/mop.1103},
Key = {6942592}
}
@article{fds283818,
Author = {Fan, GX and Liu, QH},
Title = {The cgfft method with a discontinuous fft
algorithm},
Journal = {Microwave and Optical Technology Letters},
Volume = {29},
Number = {1},
Pages = {47-49},
Publisher = {WILEY},
Year = {2001},
Month = {April},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.1079},
Abstract = {In the conjugate gradient-fast Fourier transform (CGFFT)
method, the FFT is used to evaluate the convolution
integrals. When the function to be transformed has
discontinuities, the accuracy of the FFT results, and thus
the CGFFT results, will degrade. In this letter, an
efficient FFT algorithm is developed for discontinuous
functions with both uniform and nonuniform sampled data,
with O(Np + Nlog N) complexity, where N is the number of
sampling points and p is the interpolation order. The
algorithm is incorporated into the CGFFT method. Numerical
results for slabs demonstrate the efficiency and accuracy of
the new FFT and CGFFT algorithms. © 2001 John Wiley & Sons,
Inc.},
Doi = {10.1002/mop.1079},
Key = {fds283818}
}
@article{01296582557,
Author = {Fan, GX and Liu, QH and Hutchinson, SA},
Title = {FDTD and PSTD simulations for plasma applications},
Journal = {Ieee Transactions on Plasma Science},
Volume = {29},
Number = {2 II},
Pages = {341-348},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2001},
Month = {April},
ISSN = {0093-3813},
url = {http://dx.doi.org/10.1109/27.922744},
Keywords = {Finite difference method;Boundary conditions;Electron
cyclotron resonance;Plasma interactions;Algorithms;Time
domain analysis;Frequency domain analysis;Computer
simulation;},
Abstract = {Three-dimensional finite-difference time-domain (FDTD) and
pseudospectral time-domain (PSTD) algorithms, with perfectly
matched layer absorbing boundary condition, are presented
for nonmagnetized plasma as a special case of general
inhomogeneous, dispersive, conductive media. The algorithms
are tested for three typical frequency bands, and an
excellent agreement between the FDTD/PSTD numerical results
and analytical solutions is obtained for all cases. Several
applications, such as laser-pulse propagation in plasma
hollow channels, surface-wave propagation along a plasma
column of finite length, and energy deposition of electron
cyclotron resonance plasma source, demonstrate the
capability and effectiveness of these algorithms. The PSTD
algorithm is more efficient and accurate than the FDTD
algorithm, and is suitable for large-scale problems, while
the FDTD algorithm is more suitable for fine details. The
numerical results also show that plasma has complex
transient responses, especially in the low-frequency and
resonance regimes. Because of their flexibility and
generality, the algorithms and computer programs can be used
to simulate various electromagnetic waves-plasma
interactions with complex geometry and medium properties,
both in time and frequency domains.},
Doi = {10.1109/27.922744},
Key = {01296582557}
}
@article{6884828,
Author = {Xu, XM and Liu, QH},
Title = {Fast spectral-domain method for acoustic scattering
problems.},
Journal = {Ieee Transactions on Ultrasonics, Ferroelectrics, and
Frequency Control},
Volume = {48},
Number = {2},
Pages = {522-529},
Year = {2001},
Month = {March},
ISSN = {0885-3010},
url = {http://www.ncbi.nlm.nih.gov/pubmed/11370366},
Keywords = {conjugate gradient methods;fast Fourier transforms;integral
equations;spectral-domain analysis;ultrasonic
scattering;},
Abstract = {This paper presents the application of the
conjugate-gradient (CG) fast Fourier transform (FFT)
(CG-FFT) method and the CG nonuniform FFT (CG-NUFFT) method
for the integral equation arising from acoustic scattering
problems. In the conventional method of moments (MoM) for
integral equations, the CPU and memory requirements are
O(N3) and O(N2), respectively, where N is the number of
unknowns in the problem. The CG-FFT method, which combines
the iterative conjugate-gradient method with FFT, reduces
these requirements to O(KN log2 N) and O(N), respectively,
where K is the number of CG iterations. The CG-NUFFT method
differs from the CG-FFT method in that it makes use of
nonuniform FFT algorithms instead of FFT to allow a
nonuniform discretization. Therefore, the CG-NUFFT method
can solve the integral equation with both uniform and
nonuniform grid while retaining the efficiency of the CG-FFT
method. These two methods are applied to solve for
two-dimensional constant density acoustic scattering
problems. Numerical results demonstrate that they can solve
much larger problems than the MoM.},
Doi = {10.1109/58.911735},
Key = {6884828}
}
@article{fds341220,
Author = {Fan, GX and Liu, QH and Hesthaven, JS},
Title = {Multi-domain pseudospectral time-domain method for lossy
media},
Journal = {Ieee Antennas and Propagation Society, Ap S International
Symposium (Digest)},
Volume = {4},
Pages = {842-845},
Year = {2001},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.2001.959597},
Abstract = {Multi-domain psuedospectral time-domain (PSTD) algorithm was
studied to model electromagnetic scattering from
two-dimensional buried objects in lossy media. The algorithm
was applied to model various ground penetrating radar system
applications involving interfaces of arbitary shape in a
lossy half space. Results demonstrated the effectiveness of
multi-domain PSTD algorithms as a high-order time-domain
solver for Maxwell equations.},
Doi = {10.1109/APS.2001.959597},
Key = {fds341220}
}
@article{01246542265,
Author = {Xu, X.M. and Liu, Q.H.},
Title = {Fast spectral-domain method for acoustic scattering
problems},
Journal = {IEEE Transactions on Ultrasonics, Ferroelectrics, and
Frequency Control},
Volume = {48},
Number = {2},
Pages = {522 - 529},
Year = {2001},
url = {http://dx.doi.org/10.1109/58.911735},
Keywords = {Fast Fourier transforms;Method of moments;Integral
equations;Iterative methods;Problem solving;Algorithms;},
Abstract = {This paper presents the application of the
conjugate-gradient (CG) fast Fourier transform (FFT)
(CG-FFT) method and the CG nonuniform FFT (CG-NUFFT) method
for the integral equation arising from acoustic scattering
problems. In the conventional method of moments (MoM) for
integral equations, the CPU and memory requirements are
O(N<sup>3</sup>) and O(N<sup>2</sup>), respectively, where N
is the number of unknowns in the problem. The CG-FFT method,
which combines the iterative conjugate-gradient method with
FFT, reduces these requirements to O(KN log<sub>2</sub> N)
and O(N), respectively, where K is the number of CG
iterations. The CG-NUFFT method differs from the CG-FFT
method in that it makes use of nonuniform FFT algorithms
instead of FFT to allow a nonuniform discretization.
Therefore, the CG-NUFFT method can solve the integral
equation with both uniform and nonuniform grid while
retaining the efficiency of the CG-FFT method. These two
methods are applied to solve for two-dimensional constant
density acoustic scattering problems. Numerical results
demonstrate that they can solve much larger problems than
the MoM.},
Key = {01246542265}
}
@article{01216514363,
Author = {Fan, G.-X. and Liu, Q.-H.},
Title = {Pseudospectral time-domain algorithm applied to
electromagnetic scattering from electrically large
objects},
Journal = {Microwave and Optical Technology Letters},
Volume = {29},
Number = {2},
Pages = {123 - 125},
Year = {2001},
url = {http://dx.doi.org/10.1002/mop.1103},
Abstract = {The pseudospectral time-domain (PSTD) algorithm is extended
to model the electromagnetic scattering from both 2-D and
3-D objects. The plane-wave excitation and the time-domain
near-far feld transforms in the stretched coordinates are
efficiently incorporated into the scattered-field PSTD
algorithm. Numerical results demonstrate the effectiveness
of the algorithm in wave-scattering problems. © 2001
John Wiley and Sons, Inc.},
Key = {01216514363}
}
@article{02417134224,
Author = {Zeng, Y.Q. and Liu, Q.H.},
Title = {Acoustic landmine detection: A 3D poroelastic
model},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {4394},
Number = {1},
Pages = {583 - 594},
Address = {Orlando, FL, United States},
Year = {2001},
url = {http://dx.doi.org/10.1117/12.445511},
Keywords = {Acoustic wave propagation;Elastic waves;Attenuation;Soils;Finite
difference method;Computational methods;Computer
simulation;},
Abstract = {Acoustic waves can be a viable tool for the detection and
identification of land mines, unexplored ordnance (UXO) and
other buried objects. Design of acoustic instruments and
interpretation and processing of acoustic measurements call
for accurate numerical models to simulate acoustic wave
propagation in a heterogeneous soil with buried objects.
Compared with the traditional seismic exploration, high
attenuation is unfortunately ubiquitous for shallow surface
acoustic measurements because of the loose soil and the
fluid in its pore space. To adequately model such acoustic
attenuation, we propose a comprehensive multidimensional
finite-difference time-domain model to simulate the acoustic
wave interactions with land mines and soils based on the
Blot theory for poroelastic media. For the truncation of the
computational domain, we use the perfectly matched layer
(PML). The method is validated by comparison with analytical
solutions. Unlike the pure elastic wave model, this
efficient PML-FDTD model for poroelastic media incorporates
the interactions of waves and the fluid-saturated pore
space. Several typical land mine detection measurements are
simulated to illustrate the application.},
Key = {02417134224}
}
@article{01466729345,
Author = {Zeng, Y.Q. and He, J.Q. and Liu, Q.H.},
Title = {The application of the perfectly matched layer in numerical
modeling of wave propagation in poroelastic
media},
Journal = {Geophysics},
Volume = {66},
Number = {4},
Pages = {1258 - 1266},
Year = {2001},
url = {http://dx.doi.org/10.1190/1.1487073},
Keywords = {Boundary conditions;Convolution;Finite difference
method;Algorithms;},
Abstract = {The perfectly matched layer (PML) was first introduced by
Berenger as a material absorbing boundary condition (ABC)
for electromagnetic waves. In this paper, a method is
developed to extend the perfectly matched layer to
simulating seismic wave propagation in poroelastic media.
This nonphysical material is used at the computational edge
of a finite-difference algorithm as an ABC to truncate
unbounded media. The incorporation of PML in Biot's
equations is different from other PML applications in that
an additional term involving convolution between
displacement and a loss coefficient in the PML region is
required. Numerical results show that the PML ABC attenuates
the outgoing waves effectively.},
Key = {01466729345}
}
@article{01336615541,
Author = {Zeng, YQ and Liu, QH},
Title = {Acoustic detection of buried objects in 3-D fluid saturated
porous media: Numerical modeling},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {39},
Number = {6},
Pages = {1165-1173},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2001},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.927434},
Keywords = {Acoustic surface wave devices;Mine explosions;Remote
sensing;Ordnance;Soils;Time domain analysis;Finite
difference method;Computer simulation;},
Abstract = {Acoustic waves can be a viable tool for the detection and
identification of land mines, unexplored ordnance (UXO), and
other buried objects. Design of acoustic instruments and
interpretation and processing of acoustic measurements call
for accurate numerical models to simulate acoustic wave
propagation in a heterogeneous soil with buried objects.
Compared with the traditional seismic exploration, high
attenuation is unfortunately ubiquitous for shallow surface
acoustic measurements because of the loose soil and the
fluid in its pore space. To adequately model such acoustic
attenuation, we propose a comprehensive multidimensional
finite-difference time-domain (FDTD) model to simulate the
acoustic wave interactions with land mines and soils based
on the Biot theory for poroelastic media. For the truncation
of the computational domain, we use the perfectly matched
layer (PML). The method is validated by comparison with
analytical solutions. Unlike the pure elastic wave model,
this efficient PML-FDTD model for poroelastic media
incorporates the interactions of waves and the
fluid-saturated pore space. Several typical land mine
detection measurements are simulated to illustrate the
application.},
Doi = {10.1109/36.927434},
Key = {01336615541}
}
@article{01336615559,
Author = {Zhang, ZQ and Liu, QH},
Title = {Two nonlinear inverse methods for electromagnetic induction
measurements},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {39},
Number = {6},
Pages = {1331-1339},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2001},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.927456},
Keywords = {Remote sensing;Inverse problems;Fast Fourier
transforms;Approximation theory;Computational
complexity;Algorithms;},
Abstract = {We develop two nonlinear inverse methods to reconstruct the
conductivity profile from electromagnetic induction (EMI)
measurements: the improved two-step inverse method based on
the extended Born approximation (EBA) and the combination of
the EBA and the contrast source inversion (CSI) method. In
the first method, the nonlinear problem is recast as a
two-step linear inversion and is solved by using the
extended Born approximation. We improve this method with the
fast Fourier transform (FFT) algorithm and by a
conjugate-gradient optimization procedure. For a problem
with N unknown pixels and M measurement data points, the
computational time of this inverse EBA procedure is reduced
to O(MN) in the first step (i.e., the underdetermined linear
problem) and to O(N log2 N) in the second step (i.e., the
well-determined linear problem) using the newly developed
FFT-EBA method. Furthermore, the memory requirement is
reduced to O(MTN) (MT is the number of transmitters). In the
second inverse method, we apply the contrast source
inversion (CSI) method, but use the two-step linear
inversion result as the initial solution. By using FFT, the
CPU time costs O(C1MN + C2N log2 N) in each iteration of the
CSI procedure. Numericai examples illustrate the
effectiveness of these methods, even up to a high contrast
of 100:1.},
Doi = {10.1109/36.927456},
Key = {01336615559}
}
@article{01286576336,
Author = {Zhang, ZQ and Liu, QH},
Title = {Three-dimensional weak-form conjugate- and
biconjugate-gradient FFT methods for volume integral
equations},
Journal = {Microwave and Optical Technology Letters},
Volume = {29},
Number = {5},
Pages = {350-356},
Publisher = {WILEY},
Year = {2001},
ISSN = {0895-2477},
url = {http://dx.doi.org/10.1002/mop.1176},
Keywords = {Numerical methods;Fast Fourier transforms;Three
dimensional;Integral equations;Maxwell equations;Response
time (computer systems);Method of moments;Wave
equations;Tensors;Green's function;},
Abstract = {A large-scale three-dimensional volume integral equation
solution for electromagnetic radiation and scattering
problems remains a great challenge in spite of many ongoing
research efforts. The conventional method of moments,
although accurate and flexible, is limited to small-scale
problems because of its large requirement of computer memory
and computation time. In this paper, we develop two fast
methods, the weak-form conjugate- and biconjugate-gradient
FFT methods, to solve the Fredholm integral equation of the
second kind arising from Maxwell's equations in three
dimensions. The weak form is a modified version of the
Zwamborn-van den Berg formulation, where the singularity is
circumvented by employing the weak-form discretization by
rooftop vectorial basis and testing functions. Both
weak-form CG-FFT and BCG-FFT methods require O(N log2 N) CPU
time, and O(N) computer memory, but the latter converges
three-six times faster than the CG-FFT method. We validate
the numerical results by comparing them with analytical
solutions to multilayer spherical media, and with other
published results.},
Doi = {10.1002/mop.1176},
Key = {01286576336}
}
@article{01206504169,
Author = {Liu, QH and Zhang, ZQ and Xu, XM},
Title = {The hybrid extended born approximation and CG-FFT method for
electromagnetic induction problems},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {39},
Number = {2},
Pages = {347-355},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2001},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.905243},
Keywords = {Approximation theory;Fast Fourier transforms;Convergence of
numerical methods;Integral equations;Iterative
methods;},
Abstract = {We propose the hybridization of the extended Born
approximation (EBA) with the conjugate-gradient fast Fourier
transform (CG-FFT) method to improve the efficiency of
numerical solution of electromagnetic induction problems.
This combination improves the solution efficiency in two
ways. First, using the FFT in the extended Born
approximation decreases the computational cost of the
conventional EBA method from O(N2) to O(N log2N) arithmetic
operations, where N is the number of unknowns in the
problem. This approach, referred to as the FFT-EBA method,
applies to problems with a fairly large contrast. Secondly,
using the EBA as a partial preconditioner for the CG-FFT
method increases the convergence speed of the conventional
CG-FFT method. This second approach, referred to as the
EBA-CGFFT method, is in principle applicable to all problems
with a homogeneous background, but is particularly efficient
for problems with a higher contrast. Numerical experiments
suggest that the combination of these two methods is more
accurate and more efficient for electromagnetic induction
problems.},
Doi = {10.1109/36.905243},
Key = {01206504169}
}
@article{7214891,
Author = {Zeng, YQ and He, JQ and Liu, QH},
Title = {The application of the perfectly matched layer in numerical
modeling of wave propagation in poroelastic
media},
Journal = {Geophysics (Usa)},
Volume = {66},
Number = {4},
Pages = {1258-1266},
Publisher = {Society of Exploration Geophysicists},
Year = {2001},
url = {http://dx.doi.org/10.1190/1.1487073},
Keywords = {seismic waves;wave propagation;},
Abstract = {The perfectly matched layer (PML) was first introduced by
Berenger as a material absorbing boundary condition (ABC)
for electromagnetic waves. A method is developed to extend
the PML to simulating seismic wave propagation in
poroelastic media. This nonphysical material is used at the
computational edge of a finite-difference algorithm as an
ABC to truncate unbounded media. The incorporation of PML in
Biot's equations is different from other PML applications in
that an additional term involving convolution between
displacement and a loss coefficient in the PML region is
required. Numerical results show that the PML ABC attenuates
the outgoing waves effectively},
Doi = {10.1190/1.1487073},
Key = {7214891}
}
@article{7350122,
Author = {Zeng, YQ and Liu, QH},
Title = {Acoustic landmine detection: a 3D poroelastic
model},
Journal = {Proc. Spie Int. Soc. Opt. Eng. (Usa)},
Volume = {4394},
Number = {1},
Pages = {583-594},
Publisher = {SPIE},
Address = {Orlando, FL, USA},
Year = {2001},
url = {http://dx.doi.org/10.1117/12.445511},
Keywords = {acoustic applications;acoustic wave propagation;buried
object detection;finite difference time-domain
analysis;military equipment;porosity;remote
sensing;},
Abstract = {Acoustic waves can be a viable tool for the detection and
identification of land mines, unexploded ordnance (UXO) and
other buried objects. Design of acoustic instruments and
interpretation and processing of acoustic measurements call
for accurate numerical models to simulate acoustic wave
propagation in a heterogeneous soil with buried objects.
Compared with the traditional seismic exploration, high
attenuation is unfortunately ubiquitous for shallow surface
acoustic measurements because of the loose soil and the
fluid in its pore space. To adequately model such acoustic
attenuation, we propose a comprehensive multidimensional
finite-difference time-domain model to simulate the acoustic
wave interactions with land mines and soils based on the
Biot theory for poroelastic media. For the truncation of the
computational domain, we use the perfectly matched layer
(PML). The method is validated by comparison with analytical
solutions. Unlike the pure elastic wave model, this
efficient PML-FDTD model for poroelastic media incorporates
the interactions of waves and the fluid-saturated pore
space. Several typical land mine detection measurements are
simulated to illustrate the application},
Doi = {10.1117/12.445511},
Key = {7350122}
}
@article{fds283802,
Author = {Liu, QH and Zhang, ZQ},
Title = {A Novel inverse algorithm for borehole induction
measurements using a spectral hybrid EBA forward
method},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4129},
Pages = {406-417},
Publisher = {SPIE},
Year = {2000},
Month = {December},
url = {http://dx.doi.org/10.1117/12.390641},
Abstract = {We invert for the axisymmetric conductivity distribution
from borehole electromagnetic induction measurements using a
two-step linear inversion method based on a fast Fourier and
Hankel transform enhanced extended Born approximation. In
this method, the inverse problem is first cast as an under-
determined linear least-norm problem for the induced
electric current density; from the solution of this induced
current density, the unknown conductivity distribution is
then obtained by solving an over-determined linear problem
using the newly developed, fast Fourier and Hankel transform
enhanced extended Born approximation. Numerical results show
that this inverse method is applicable to a very high
conductivity contrast. It is a natural extension of the
original two-step linear inversion method of Torres-Verdin
and Habashy to axisymmetric media. In the first step, the
CPU time costs O(N2). In the second step, the CPU time costs
O(N log2 N) where N is the number of unknowns. Because of
the fast Fourier and Hankel transform algorithm, this
inverse method is actually more efficient than the
conventional, brute-force first-order Born
approximation.},
Doi = {10.1117/12.390641},
Key = {fds283802}
}
@article{fds283804,
Author = {Zhang, ZQ and Liu, QH},
Title = {Simulation of borehole induction using the hybrid extended
Born approximation and CG-FFHT method},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4129},
Pages = {165-174},
Publisher = {SPIE},
Year = {2000},
Month = {December},
url = {http://dx.doi.org/10.1117/12.390613},
Abstract = {We propose the hybridization of the extended Born
approximation (EBA) with the conjugate-gradient fast Fourier
Hankel transform (CG-FFHT) method to improve the efficiency
of numerical solution of borehole induction problems in
axisymmetric media. First, we use the FFHT to accelerate the
EBA as a nonlinear approximation to induction problems,
resulting in an algorithm with O(N log 2 N) arithmetic
operations, where N is the number of unknowns in the
problem. This improved EBA is accurate for most formations
encountered. Then, for formations with extremely high
contrasts, we utilize this improved EBA as a partial
preconditioner in the CG-FFHT method to solve the problem
accurately with few iterations. The seamless combination of
these two approaches provides an automatic way toward the
efficient and accurate modeling of induction measurements in
axisymmetric media.},
Doi = {10.1117/12.390613},
Key = {fds283804}
}
@article{fds283806,
Author = {Fan, GX and Liu, QH},
Title = {An FDTD algorithm with perfectly matched layers for general
dispersive media},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {48},
Number = {5},
Pages = {637-646},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2000},
Month = {December},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/8.855481},
Abstract = {A three-dimensional (3-D) finite-difference time-domain
(FDTD) algorithm with perfectly matched layer (PML)
absorbing boundary condition (ABC) is presented for general
inhomogeneous, dispersive, conductive media. The modified
time-domain Maxwell's equations for dispersive media are
expressed in terms of coordinate-stretching variables. We
extend the recursive convolution (RC) and piecewise linear
recursive convolution (PLRC) approaches to arbitrary
dispersive media in a more general form. The algorithm is
tested for homogeneous and inhomogeneous media with three
typical kinds of dispersive media, i.e., Lorentz medium,
unmagnetized plasma, and Debye medium. Excellent agreement
between the FDTD results and analytical solutions is
obtained for all testing cases with both RC and PLRC
approaches. We demonstrate the applications of the algorithm
with several examples in subsurface radar detection of
mine-like objects, cylinders, and spheres buried in a
dispersive half-space and the mapping of a curved interface.
Because of their generality, the algorithm and computer
program can be used to model biological materials,
artificial dielectrics, optical materials, and other
dispersive media. © 2000 IEEE.},
Doi = {10.1109/8.855481},
Key = {fds283806}
}
@article{fds283808,
Author = {Liu, QH and Zhang, ZQ and Xu, XM},
Title = {Spectral hybrid EBA method for integral equations},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {4},
Pages = {2328-2331},
Year = {2000},
Month = {December},
ISSN = {0272-4693},
Abstract = {A spectral hybrid extended Born approximation (SHEBA) method
combining the extended Born approximation (EBA) and the
conjugate-gradient fast Fourier transform (CG-FFT) is
proposed as a solution of integral equations. The hybrid
method is in principle applicable to all problems with a
homogeneous background, but particularly efficient for
problems with a higher contrast.},
Key = {fds283808}
}
@article{fds283809,
Author = {Zhang, ZQ and Liu, QH},
Title = {Hybrid extended born approximation and CG-FFHT method for
axisymmetric media},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {2},
Pages = {602-605},
Year = {2000},
Month = {December},
ISSN = {0272-4693},
Abstract = {The fast Fourier and fast Hankel transform (FFHT) algorithm
is used to accelerate the extended Born approximation (EBA)
as a nonlinear approximation to borehole induction problems,
resulting in an algorithm with O(N log2 N) arithmetic
operation. The improved EBA is used as a partial
preconditioner in the conjugate-gradient (CG)-FFHT method to
solve the problem accurately with few iterations. Numerical
results demonstrate the efficacy of this hybrid
method.},
Key = {fds283809}
}
@article{6805016,
Author = {Fan, GX and Liu, QH},
Title = {Fast fourier transform of functions with jump
discontinuities},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {148-151},
Address = {Salt Lake City, UT, USA},
Year = {2000},
Month = {December},
ISSN = {0272-4693},
url = {http://dx.doi.org/10.1109/APS.2000.873732},
Keywords = {computational complexity;fast Fourier transforms;functional
analysis;interpolation;signal sampling;},
Abstract = {A fast algorithm for the evaluation of Fourier transform of
piecewise smooth functions is presented. By using a double
interpolation procedure, the algorithm can be applied to
both uniform and nonuniform sampled data.},
Key = {6805016}
}
@article{fds283812,
Author = {Xu, XM and Liu, QH},
Title = {Conjugate-gradient nonuniform fast Fourier transform
(CG-NUFFT) method for one- and two-dimensional
media},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {4},
Pages = {2332-2335},
Year = {2000},
Month = {December},
ISSN = {0272-4693},
Abstract = {A novel method combining the conjugate-gradient and
nonuniform fast Fourier transform (CG-NUFFT) algorithms for
solving integral equation in electromagnetics is presented.
The CG-NUFFT method has been applied to one- and
two-dimensional inhomogeneous media. Numerical results show
the advantages of the CG-NUFFT method over the CG-FFT method
for problems with both electrically large and small
regions.},
Key = {fds283812}
}
@article{fds337120,
Author = {Tian, B and Liu, QH},
Title = {Nonuniform fast cosine transform and chebyshev PSTD
algorithms},
Journal = {Electromagnetic Waves (Cambridge, Mass.)},
Volume = {28},
Pages = {253-273},
Publisher = {EMW Publishing},
Year = {2000},
Month = {December},
url = {http://dx.doi.org/10.2528/PIER99102803},
Doi = {10.2528/PIER99102803},
Key = {fds337120}
}
@article{fds283814,
Author = {Zhang, ZQ and Liu, QH},
Title = {Reconstruction of axisymmetric media with an FFHT-enhanced
extended born approximation},
Journal = {Inverse Problems},
Volume = {16},
Number = {5},
Pages = {1281-1295},
Publisher = {IOP Publishing},
Year = {2000},
Month = {October},
url = {http://dx.doi.org/10.1088/0266-5611/16/5/310},
Abstract = {We invert for the axisymmetric conductivity distribution
from borehole electromagnetic induction measurements using a
two-step linear inversion method based on a fast Fourier and
Hankel transform (FFHT) enhanced extended Born approximation
(EBA). In this method, the inverse problem is first cast as
an under-determined linear least-norm problem for the
induced electric current density; from the solution of this
induced current density, the unknown conductivity
distribution is then obtained by solving an over-determined
linear problem using the newly developed, FFHT-enhanced EBA.
Numerical results show that this inverse method is
applicable to a very high conductivity contrast. It is a
natural extension of the original two-step linear inversion
method of Torres-Verdin and Habashy to axisymmetric media.
In the first step, the CPU time costs O(N2-). In the second
step, the CPU time costs O(N log2 N) where N is the number
of unknowns. Because of the FFHT algorithm, this inverse
method is actually more efficient than the conventional,
brute-force first-order Born approximation.},
Doi = {10.1088/0266-5611/16/5/310},
Key = {fds283814}
}
@article{fds283816,
Author = {Fan, GX and Liu, QH and Blanchard, SP},
Title = {3-D numerical mode-matching (NMM) method for resistivity
well-logging tools},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {48},
Number = {10},
Pages = {1544-1552},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2000},
Month = {October},
ISSN = {0018-926X},
url = {http://dx.doi.org/10.1109/8.899671},
Abstract = {A three-dimensional (3-D) numerical mode-matching (NMM)
method is presented for Poisson's equation in general
inhomogeneous media. It reduces the original 3-D problem
into a series of two-dimensional (2-D) eigenvalue problems
plus a one-dimensional (1-D) layered medium problem, which
can be modeled efficiently by a recursion procedure. The
algorithm is tested for several 3-D inhomogeneous media and
an excellent agreement between the NMM and analytical
solutions is obtained for all test cases. We demonstrate
some typical applications of the 3-D NMM algorithm in
resistivity well logging, including invasion zones of
noncircular shape, vertical and horizontal fractures, and
horizontal wells. The solution procedure proposed is
directly applicable to wave propagation in 3-D inhomogeneous
media.},
Doi = {10.1109/8.899671},
Key = {fds283816}
}
@article{6933222,
Author = {Zeng, Y and Liu, QH},
Title = {Poroelastic model for acoustic land mine
detection},
Journal = {Smart Structures and Materials 2005: Active Materials:
Behavior and Mechanics},
Volume = {4038},
Pages = {748-759},
Publisher = {SPIE},
Address = {Orlando, FL, USA},
Year = {2000},
Month = {August},
ISSN = {0277-786X},
url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000166957700075&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
Keywords = {acoustic wave diffraction;acoustic wave propagation;buried
object detection;finite difference time-domain
analysis;military equipment;porosity;Rayleigh
waves;sand;seismic waves;soil;},
Abstract = {Acoustic waves can be a viable tool for the detection and
identification of landmines and unexploded ordnance. Design
of acoustic instruments and interpretation and processing of
acoustic measurements call for accurate numerical models to
simulate acoustic wave propagation in a heterogeneous soil
with buried objects. Compared with the traditional seismic
exploration, high attenuation is unfortunately ubiquitous
for shallow surface acoustic measurements because of the
loose soil and the fluid in its pore space. To adequately
model such acoustic attenuation, we propose a comprehensive
model to simulate the acoustic wave interactions with
landmines and soils based on the Biot theory for poroelastic
media. The finite-difference time-domain method is then used
to solve the Biot equations. For the truncation of the
computational domain in the FDTD method, we extend the
acoustic and elastic perfectly matched layer (PML) to
poroelastic media. Numerical experiments show that, with
only 10 cells of PML medium, a high attenuation of about 50
dB can be achieved for outgoing waves. The numerical model
is validated by comparison with analytical solutions. Unlike
the pure elastic wave mode, this efficient PML-FDTD model
for poroelastic media incorporates the interactions of waves
and the fluid-saturated variation with offset in three
different ground media: dry sand, fully water saturated sand
and partly water saturated sand. The interaction of elastic
wave with a plastic mine buried in dry sand is simulated.
The results show that the surface wave is significantly
influenced by the existence of a mine-like object. The
diffraction of the surface wave can serve as an acoustic
target signature},
Doi = {10.1117/12.396304},
Key = {6933222}
}
@article{fds283815,
Author = {Liu, QH and Xu, XM and Tian, B and Zhang, ZQ},
Title = {Applications of nonuniform fast transform algorithms in
numerical solutions of differential and integral
equations},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {38},
Number = {4 I},
Pages = {1551-1560},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {2000},
Month = {July},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.851955},
Abstract = {We review our recent efforts to apply the nonuniform fast
Fourier transform (NUFFT) and related fast transform
algorithms to numerical solutions of Maxwell's equations in
time and frequency domains. The NUFFT is a fast algorithm to
perform the discrete Fourier transform of data sampled
nonuniformly (NUDFT). Through oversampling and fast
interpolation, the forward and inverse NUFFT's can be
achieved with O(N log 2 N) arithmetic operations,
asymptotically the same as the regular fast Fourier
transform (FFT) algorithms. Using the NUFFT scheme, we
develop nonuniform fast cosine transform (NUFCT) and fast
Hankel transform (NUFHT) algorithms. These algorithms
provide an efficient tool for numerical differentiation and
integration, the key in the solutions to differential
equations and volume integral equations. We present sample
applications of these nonuniform fast transform algorithms
in the numerical solution to Maxwell's equations.},
Doi = {10.1109/36.851955},
Key = {fds283815}
}
@article{fds283813,
Author = {Liu, QH and Zhang, ZQ},
Title = {Erratum: Nonuniform fast Hankel transform (NUFHT) algorithm
(Applied Optics (1842))},
Journal = {Applied Optics},
Volume = {39},
Number = {11},
Pages = {1842},
Publisher = {The Optical Society},
Year = {2000},
Month = {April},
ISSN = {0003-6935},
url = {http://dx.doi.org/10.1364/AO.39.001842},
Doi = {10.1364/AO.39.001842},
Key = {fds283813}
}
@article{fds283810,
Author = {Xu, XM and Liu, QH},
Title = {Conjugate-gradient nonuniform fast Fourier transform
(CG-NUFFT) method for one- and two-dimensional
media},
Journal = {Microwave and Optical Technology Letters},
Volume = {24},
Number = {6},
Pages = {385-389},
Publisher = {WILEY},
Year = {2000},
Month = {March},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(20000320)24:6<385::AID-MOP8>3.0.CO;2},
Abstract = {A novel method combining the conjugate-gradient and
nonuniform fast Fourier transform (CG-NUFFT) algorithms for
solving integral equations in electromagnetics is presented.
The CG-NUFFT method has been applied to one- and
two-dimensional inhomogeneous media. Numerical results show
the advantages of the CG-NUFFT method over the CG-FFT method
for problems with both electrically large and small
regions.},
Doi = {10.1002/(SICI)1098-2760(20000320)24:6<385::AID-MOP8>3.0.CO;2},
Key = {fds283810}
}
@article{7542290,
Author = {Liu, QH and Xu, XM and Zhang, ZQ},
Title = {Applications of nonuniform fast transform algorithms in
numerical solutions of integral equations},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {897-904},
Address = {Monterey, CA, USA},
Year = {2000},
Month = {January},
Keywords = {conjugate gradient methods;electromagnetic wave
scattering;fast Fourier transforms;Hankel
transforms;integral equations;iterative methods;numerical
analysis;},
Abstract = {We review our recent efforts to apply the nonuniform fast
Fourier transform (NUFFT) and fast Hankel transform (NUFHT)
algorithms to numerical solutions of electromagnetic
integral equations in frequency domains. The NUFFT is a fast
algorithm to perform the discrete Fourier transform of data
sampled nonuniformly with O(N log2 N) arithmetic operations.
Using the NUFFT scheme, we develop the nonuniform fast
Hankel transform (NUFHT) algorithm. These NUFFT and NUFHT
algorithms are then combined with the conjugate-gradient
method to solve integral equations in Cartesian and
cylindrical coordinates.},
Key = {7542290}
}
@article{fds283807,
Author = {Liu, QH and Sinha, BK},
Title = {Multipole acoustic waveforms in fluid-filled boreholes in
biaxially stressed formations: A finite-difference
method},
Journal = {Geophysics},
Volume = {65},
Number = {1},
Pages = {190-201},
Publisher = {Society of Exploration Geophysicists},
Year = {2000},
Month = {January},
url = {http://dx.doi.org/10.1190/1.1444710},
Abstract = {A finite-difference method is developed to simulate elastic
wave propagation in a borehole surrounded by a biaxially
stressed solid formation. The linear elastic formation is
altered by such tectonic stresses that cause significant
changes in the characteristics of wave propagation in a
borehole. The 2.5-dimensional problem addressed in this work
concerns the three-dimensional wave propagation in a medium
inhomogeneous in two spatial coordinates transverse to the
borehole axis. A second-order finite-difference method is
developed to solve the partial differential equations
arising from a published acoustoelastic model for borehole
acoustic wave propagation in prestressed formations. The
algorithm is validated and applied to model both the
borehole flexural and axisymmetric Stoneley waves. The
computed waveforms are processed by a variation of Prony's
algorithm that yields dispersion curves for flexural waves
polarized both parallel and perpendicular to the stress
direction. The flexural dispersion crossover in a uniaxially
stressed formation is quantitatively confirmed. The Stoneley
dispersion in the presence of such stresses exhibits
approximately a uniform shift toward lower slownesses over
the entire bandwidth of interest. This implies that
azimuthal averaging of formation stiffnesses approximately
yields the same effective Stoneley stiffness at different
radial positions.},
Doi = {10.1190/1.1444710},
Key = {fds283807}
}
@article{00085295057,
Author = {Tian, B and Liu, QH},
Title = {Nonuniform fast cosine transform and Chebyshev PSTD
algorithms},
Journal = {Journal of Electromagnetic Waves and Applications},
Volume = {14},
Number = {6},
Pages = {797-798},
Publisher = {Informa UK Limited},
Year = {2000},
Month = {January},
ISSN = {1070-4698},
url = {http://dx.doi.org/10.1163/156939300X01526},
Keywords = {Fast Fourier transforms;Chebyshev approximation;Algorithms;Time
domain analysis;Mathematical models;Problem
solving;Interpolation;Matrix algebra;Cosine
transforms;Inverse problems;},
Abstract = {We propose highly accurate forward and inverse nonuniform
fast cosine transform (NUFCT) algorithms for data sampled
nonuniformly. Using the fast interpolation with regular
Fourier matrices, the NUFCT algorithms requires only O(N
log2 N) arithmetic operations. These algorithms are then
utilized in the Chebyshev pseudospectral time- domain (PSTD)
method to solve Maxwell's equations on a nonuniform grid.
Representing the fields and their derivatives in terms of
Chebyshev polynomials, the derivatives on a nonuniform grid
can be calculated with the NUFCT algorithms. The Chebyshev
PSTD methods only requires π cells per wavelength on the
average. Numerical results show the efficiency of the fast
NUFCT and Chebyshev PSTD algorithms.},
Doi = {10.1163/156939300X01526},
Key = {00085295057}
}
@article{fds319948,
Author = {Fan, GX and Liu, QH},
Title = {Fast Fourier Transform of functions with jump
discontinuities},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {890-896},
Year = {2000},
Month = {January},
Abstract = {A fast algorithm is presented for the evaluation of the
Fourier transform of piecewise smooth functions with
uniformly and non-uniformly sampled data by using a double
interpolation procedure. The complexity of the algorithm is
O(Np+Nlog(N)) where p is the interpolation
order.},
Key = {fds319948}
}
@article{00105364682,
Author = {Zeng, YQ and Liu, QH},
Title = {Poroelastic model for acoustic landmine detection},
Journal = {Proceedings of Spie the International Society for Optical
Engineering},
Volume = {4038},
Pages = {I/-},
Address = {Orlando, FL, USA},
Year = {2000},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.396304},
Keywords = {Bombs (ordnance);Acoustic wave propagation;Mathematical
models;Soils;Acoustic variables measurement;Attenuation;Finite
difference method;Time domain analysis;Sand;Water;Elastic
waves;Computer simulation;},
Abstract = {Acoustic waves can be a viable tool for the detection and
identification of land mines and unexploded ordnance (UXO).
Design of acoustic instruments and interpretation and
processing of acoustic measurements call for accurate
numerical models to simulate acoustic wave propagation in a
heterogeneous soil with buried objects. Compared with the
traditional seismic exploration, high attenuation is
unfortunately ubiquitous for shallow surface acoustic
measurements because of the loose soil and the fluid in its
pore space. To adequately model such acoustic attenuation,
we propose a comprehensive model to simulate the acoustic
wave interactions with land mines and soils based on the
Biot theory for poroelastic media. The finite-difference
time-domain method is then used to solve the Biot equations.
For the truncation of the computational domain in the FDTD
method, we extend the acoustic and elastic perfectly matched
layer (PML) to poroelastic media. Numerical experiments show
that, with only 10 cells of PML medium, a high attenuation
of about 50 dB can be achieved for outgoing waves. The
numerical model is validated by comparison with analytical
solutions. Unlike the pure elastic wave model, this
efficient PML-FDTD model for poroelastic media incorporates
the interactions of waves and the fluid-saturated pore
space. The difference between elastic model and poroelastic
model is investigated by studying surface wave amplitude
variation with offset (AVO) in three different ground media:
dry sand, fully water saturated sand and partly water
saturated sand. The interaction of elastic wave with a
plastic mine buried in dry sand is simulated. The results
show that the surface wave is significantly influenced by
the existence of a mine-like object. The diffraction of the
surface wave can serve as an acoustic target
signature.},
Key = {00105364682}
}
@article{fds283794,
Author = {Liu, QH},
Title = {Large-scale simulations of electromagnetic and acoustic
measurements using the pseudospectral time-domain (PSTD)
algorithm},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {37},
Number = {2 II},
Pages = {917-926},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {December},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.752210},
Abstract = {Recently a pseudospectral time-domain (PSTD) algorithm was
developed to simulate electromagnetic wave propagation. This
technique uses the fast Fourier transform (FFT) algorithm
for the spatial derivatives and uses the perfectly matched
layer (PML) to eliminate the wraparound effect due to the
spatial periodicity introduced by FFT. In this work we
further analyze this new method and compare it with the
finite-difference time-domain (FDTD) and multiresolution
time-domain (MRTD) methods for accuracy and efficiency. The
PSTD algorithm is then applied to simulate large-scale
problems for subsurface electromagnetic and acoustic
measurements. For many problems encountered since the
spatial derivatives are obtained by the PSTD algorithm for
continuous field components this algorithm has a high order
of accuracy in the spatial derivatives and thus requires
much fewer unknowns than the FDTD and MRTD methods.
Numerical results confirm the efficacy of the PSTD method.
© 1999 IEEE.},
Doi = {10.1109/36.752210},
Key = {fds283794}
}
@article{fds283795,
Author = {He, JQ and Liu, QH},
Title = {A nonuniform cylindrical FDTD algorithm with improved PML
and Quasi-PML absorbing boundary conditions},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {37},
Number = {2 II},
Pages = {1066-1072},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {December},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.752224},
Abstract = {Many applications require time-domain solutions of Maxwell's
equations in inhomogeneous conductive media involving
cylindrical geometries with both electrically small and
large structures. The conventional finite-difference
time-domain (FDTD) method with a uniform Cartesian grid will
result in a staircasing error and wastes many unnecessary
cells in regions with large structures in order to
accommodate the accurate geometrical representation in
regions with small structures. In this work an explicit FDTD
method with a nonuniform cylindrical grid is developed for
time-domain Maxwell's equations. A refined lattice is used
near sharp edges and within fine geometrical details while a
larger lattice is used outside these regions. This provides
an efficient use of limited computer memory and computation
time. We use two absorbing boundary conditions to a
nonuniform cylindrical grid: 1) the straightforward
extension of Berenger's perfectly matched layer (PML) which
is no longer perfectly matched for cylindrical interfaces
thus the name quasi-PML (QPML); 2) the improved true PML
based on complex coordinates. In practice both PML schemes
can provide a satisfactory absorbing boundary condition.
Numerical results are shown to compare the two absorbing
boundary conditions (ABC's) and to demonstrate the
effectiveness of the nonuniform grid and the absorbing
boundary conditions. © 1999 IEEE.},
Doi = {10.1109/36.752224},
Key = {fds283795}
}
@article{fds283799,
Author = {Liu, QH and Zhang, ZQ},
Title = {Nonuniform fast Hankel transform (NUFHT)
algorithm.},
Journal = {Applied Optics},
Volume = {38},
Number = {32},
Pages = {6705-6708},
Year = {1999},
Month = {November},
ISSN = {0003-6935},
url = {http://www.ncbi.nlm.nih.gov/pubmed/18324208},
Abstract = {We investigate the fast computation of Hankel transforms on
a set of nonuniformly spaced sample points. Previous fast
Hankel transform (FHT) algorithms require the sample points
to distribute uniformly in a logarithmic scale. This
limitation is removed here by the use of the newly
developed, to our knowledge, nonuniform fast Fourier
transform algorithm. The resulting nonuniform FHT algorithm
has a much higher accuracy than the previous FHT algorithms
and provides important flexibility in many
applications.},
Doi = {10.1364/ao.38.006705},
Key = {fds283799}
}
@article{fds283800,
Author = {Liu, QH and Fan, GX},
Title = {Simulations of GPR in dispersive media using a
frequency-dependent PSTD algorithm},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {37},
Number = {5 pt 1},
Pages = {2317-2324},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {September},
ISSN = {0196-2892},
url = {http://dx.doi.org/10.1109/36.789628},
Abstract = {Recently an efficient pseudospectral time-domain (PSTD)
algorithm has been developed to solve partial differential
equations in computational electromagnetics and acoustics.
It uses the fast Fourier transform (FFT) algorithm to
approximate spatial derivatives, and the perfectly matched
layer (PML) to eliminate the wraparound effect. Due to its
high accuracy in the spatial derivatives, this method
requires a significantly smaller number of unknowns than a
conventional finite-difference time-domain (FDTD) method
when solving large-scale problems. In this work, we further
extend the PSTD algorithm to frequency-dependent media and
apply the algorithm to simulate ground-penetrating radar
(GPR) measurements in a dispersive earth. The dispersion of
the soil is treated by the recursive convolution approaches.
The convergence property of the PSTD algorithm is
investigated for the scattering of a dispersive cylinder.
Multidimensional large-scale problems in GPR measurements
are presented to demonstrate the efficiency of this
frequency-dependent PSTD algorithm.},
Doi = {10.1109/36.789628},
Key = {fds283800}
}
@article{6217664,
Author = {Liu, QH},
Title = {Perfectly matched layers for elastic waves in cylindrical
and spherical coordinates},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {105},
Number = {4},
Pages = {2075-2084},
Publisher = {Acoustical Society of America (ASA)},
Year = {1999},
Month = {April},
ISSN = {0001-4966},
url = {http://dx.doi.org/10.1121/1.426812},
Keywords = {acoustic wave propagation;elastic waves;inhomogeneous
media;partial differential equations;},
Abstract = {The perfectly matched layer (PML) for elastic waves in
cylindrical and spherical coordinates is developed using an
improved scheme of complex coordinates. As is known for
electromagnetic waves, Berenger's original PML scheme does
not apply to cylindrical and spherical coordinates. The
straightforward extension of the complex coordinates for
elastic waves to cylindrical and spherical coordinates
requires extra unknowns for time- domain solutions, wasting
computer memory and computation time. The main idea of the
improved scheme in this work is the use of integrated
complex variables. It is shown that for three-dimensional
cylindrical and spherical coordinates, this improved PML
scheme requires no more unknowns than in Cartesian
coordinates. The number of unknowns can be further reduced
through the use of symmetry in the partial differential
equations. The PML scheme allows an arbitrary inhomogeneity
in the medium, and is suitable for numerical solutions of
wave equations by finite-difference, finite-element, and
pseudospectral methods for elastic waves in inhomogeneous
media with cylindrical and spherical structures.
Finite-difference time-domain (FDTD) results are shown to
demonstrate the efficacy of the PML absorbing boundary
condition.},
Doi = {10.1121/1.426812},
Key = {6217664}
}
@article{fds283796,
Author = {Liu, QH},
Title = {PML and PSTD Algorithm for Arbitrary Lossy Anisotropic
Media},
Journal = {Ieee Microwave and Guided Wave Letters},
Volume = {9},
Number = {2},
Pages = {48-50},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {January},
ISSN = {1531-1309},
url = {http://dx.doi.org/10.1109/75.755040},
Abstract = {A general perfectly matched layer (PML) formulation is
presented for lossy anisotropic media with arbitrary
permittivity, permeability, and conductivity tensors. This
PML is then used in a pseudospectral time-domain (PSTD)
algorithm for solutions of electromagnetic fields in lossy
anisotropic media. Numerical results verify the efficiency
of the PML absorbing boundary condition and the PSTD
algorithm.},
Doi = {10.1109/75.755040},
Key = {fds283796}
}
@article{fds283797,
Author = {Liu, QH and Fan, GX},
Title = {A Frequency-Dependent PSTD Algorithm for General Dispersive
Media},
Journal = {Ieee Microwave and Guided Wave Letters},
Volume = {9},
Number = {2},
Pages = {51-53},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1999},
Month = {January},
ISSN = {1531-1309},
url = {http://dx.doi.org/10.1109/75.755043},
Abstract = {Based on the Fourier representation of spatial derivatives,
the recursive convolution approaches, and the perfectly
matched layer (PML), we develop a pseudospectral time-domain
(PSTD) algorithm for electromagnetic problems involving
general dispersive media. As a result of the accurate
representation of spatial derivatives, the PSTD algorithm
for dispersive media requires only a small number of cells
per minimum wavelength, significantly reducing the number of
unknowns. Multidimensional numerical results confirm the
efficacy of the PSTD algorithm for large-scale inhomogeneous
media.},
Doi = {10.1109/75.755043},
Key = {fds283797}
}
@article{fds283798,
Author = {Nguyen, N and Liu, QH},
Title = {Regular Fourier matrices and nonuniform fast Fourier
transforms},
Journal = {Siam Journal on Scientific Computing},
Volume = {21},
Number = {1},
Pages = {283-293},
Publisher = {Society for Industrial & Applied Mathematics
(SIAM)},
Year = {1999},
Month = {January},
ISSN = {1064-8275},
url = {http://dx.doi.org/10.1137/S1064827597325712},
Abstract = {For any triple of positive integers (m, N, q), the matrix
F(m, N, q), called the (m, N, q)-regular Fourier matrix, is
defined. The regular Fourier matrices F(m, N, q) are then
applied to set up new algorithms for nonuniform fast Fourier
transforms. Numerical results show that the accuracies
obtained by our algorithms are much better than previously
reported results with the same computation complexity. The
algorithms require O(N · log2 N) arithmetic operations,
where N is the number of data points.},
Doi = {10.1137/S1064827597325712},
Key = {fds283798}
}
@article{fds341223,
Author = {Fan, GX and Liu, QH},
Title = {Pseudospectral time-domain algorithm applied to
electromagnetic scattering from electrically large
objects},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {4},
Pages = {2644-2647},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789351},
Abstract = {The pseudospectral time-domain (PSTD) algorithm is extended
to model the electromagnetic scattering from both 2-D and
3-D objects. The plane wave excitation and the time domain
near-far field transforms are efficiently incorporated into
the scattered field PSTD algorithm. Numerical results
demonstrate the effectiveness of the algorithm.},
Doi = {10.1109/APS.1999.789351},
Key = {fds341223}
}
@article{fds341221,
Author = {Jiang, H and Liu, QH},
Title = {A 2.5-D PSTD algorithm in cylindrical coordinates},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {2},
Pages = {1358-1361},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789566},
Abstract = {The finite-difference time-domain (FDTD) method has been
playing an important role in the simulations of transient
electromagnetic wave propagation and scattering. However,
when dealing with a large-scale problem the FDTD method
starts to show its limitations. It requires significant
computer memory because of the required high grid density
(number of nodes per minimum wavelength) of 10-20 even for a
moderate size problem. For large scale problems the required
grid density increases, greatly limiting the size of
solvable problems. The PSTD (pseudospectral time-domain)
method is promising in that it requires only a grid density
close to the Nyquist sampling density. Compared with the
second-order accuracy of the FDTD method, the PSTD method
has an infinite order of accuracy. Previously, the PSTD
method has been applied to Cartesian and 3-D cylindrical
coordinates. In this work, a 2.5-D PSTD algorithm is
developed for the medium which possesses an axial symmetry,
i.e., the material properties are only functions of /spl
rho/ and z. The azimuthal dependence of the fields is
accounted for analytically through a Fourier series. The
perfectly matched layer is used as the absorbing boundary
condition to truncate the computational domain. Compared
with the 3-D PSTD method it saves significant computer
memory and computational time.},
Doi = {10.1109/APS.1999.789566},
Key = {fds341221}
}
@article{fds341222,
Author = {Liu, QH and Fan, GX},
Title = {Frequency-dependent PSTD method and its applications to GPR
modeling},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {4},
Pages = {2188-2191},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789243},
Abstract = {Recently an efficient pseudospectral time-domain (PSTD)
algorithm has been developed to solve partial differential
equations, and has been extended to dispersive media. It
uses the fast Fourier transform (FFT) algorithm to
approximate spatial derivatives, and the perfectly matched
layer (PML) to eliminate the wraparound effect. Due to its
high accuracy in the spatial derivatives, this method
requires a significantly smaller number of unknowns than a
conventional finite-difference time-domain (FDTD) method
when solving large-scale problems. In this work, we apply
the algorithm to simulate ground-penetrating radar (GPR)
measurements in a dispersive earth. The dispersion of the
soil is treated by the recursive convolution approaches. The
convergence property of the PSTD algorithm is investigated
for the scattering of a dispersive cylinder.
Multidimensional large-scale problems in GPR measurements
are presented to demonstrate the efficiency of this
frequency-dependent PSTD algorithm.},
Doi = {10.1109/APS.1999.789243},
Key = {fds341222}
}
@article{fds341224,
Author = {Liu, QH},
Title = {PML-FDTD method for elastic waves in cylindrical and
spherical coordinates},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {2},
Pages = {1392-1395},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789574},
Abstract = {A perfectly matched layer (PML) is developed for elastic
waves in cylindrical and spherical coordinates using the
improved scheme of complex coordinates. With the
introduction of the integrated complex stretching variables,
the cylindrical and spherical PML schemes require no more
unknown split field components than in Cartesian
coordinates. The FDTD results confirm the efficacy of the
PML absorbing boundary condition.},
Doi = {10.1109/APS.1999.789574},
Key = {fds341224}
}
@article{6482916,
Author = {Blanchard, SP and Fan, GX and Liu, QH},
Title = {3-D numerical mode-matching (NMM) method for inhomogeneous
media},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {2},
Pages = {1194-1197},
Address = {Orlando, FL, USA},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789527},
Keywords = {electric impedance;electric potential;electrostatics;inhomogeneous
media;mode matching;numerical analysis;},
Abstract = {The numerical mode-matching (NMM) method as an efficient
algorithm has previously been used to model various
multi-region vertically and cylindrically stratified
inhomogeneous media. It has been shown that the NMM method
is more efficient than direct use of the finite element
method (FEM) to solve these problems. However the
applications of the NMM method have been limited to
two-dimensional (2-D) and two-and-a-half-dimensional (2.5-D)
problems. In this work, we extend the NMM method to
three-dimensional (3-D) inhomogeneous media, and apply the
method to model electric impedance problems using the
electrostatic approximation. Although this work models the
electric potential distribution, the solution procedure
presented here can be directly applied to wave
problems.},
Doi = {10.1109/APS.1999.789527},
Key = {6482916}
}
@article{fds341226,
Author = {Liu, QH},
Title = {PML and PSTD algorithm for arbitrary lossy bianisotropic
media},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {2},
Pages = {1370-1373},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789569},
Abstract = {The perfectly matched layer (PML) formulation for a lossy
anisotropic medium with arbitrary permittivity,
permeability, and conductivity tensors are presented using
the idea of complex coordinates. A pseudospectral
time-domain algorithm is developed to improve the accuracy
of the time domain solutions of Maxwell's equations in
arbitrary anisotropic media and to avoid the interpolation
of field components in the FDTD methods.},
Doi = {10.1109/APS.1999.789569},
Key = {fds341226}
}
@article{fds340993,
Author = {Tian, B and Liu, QH},
Title = {Nonuniform fast cosine transform and the chebyshev PSTD
algorithm},
Journal = {Ieee Antennas and Propagation Society International
Symposium: Wireless Technologies and Information Networks,
Aps 1999 Held in Conjunction With Usnc/Ursi National Radio
Science Meeting},
Volume = {4},
Pages = {2184-2187},
Year = {1999},
Month = {January},
ISBN = {078035639X},
url = {http://dx.doi.org/10.1109/APS.1999.789242},
Abstract = {Fast cosine transform (FCT) has many applications in signal
processing and computational electromagnetics. Many efforts
have been made in developing the efficient FCT algorithm.
However, to use the regular FCT algorithm, the input data
have to be uniformly distributed. This is a major limitation
of the Chebyshev pseudospectral time domain (PSTD) method.
We developed two different fast algorithms for forward
nonuniform discrete cosine transform (NUFCT) by using the
regular Fourier matrices. These algorithms have the
complexity of O(Nlog/sub 2/N) where N is the number of data
points. Unlike the uniform fast cosine transform which is
identical to its inverse, the inverse nonuniform FCT cannot
share the same algorithm. We use the conjugate-gradient fast
Fourier transform (CG-FFT) methods for the fast inverse
cosine transform (NU-IFCT).},
Doi = {10.1109/APS.1999.789242},
Key = {fds340993}
}
@article{fds283791,
Author = {Liu, QH},
Title = {The pseudospectral time-domain (PSTD) algorithm for acoustic
waves in absorptive media},
Journal = {Ieee Transactions on Ultrasonics, Ferroelectrics, and
Frequency Control},
Volume = {45},
Number = {4},
Pages = {1044-1055},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1998},
Month = {December},
ISSN = {0885-3010},
url = {http://dx.doi.org/10.1109/58.710587},
Abstract = {A technique based on the combination of Fourier
pseudospectral method and the perfectly matched layer (PML)
is developed to simulate transient acoustic wave propagation
in multidimensional, inhomogeneous, absorptive media.
Instead of the finite difference approximation in the
conventional finite-difference time-domain (FDTD) method,
this technique uses trigonometric functions, through an FFT
(fast Fourier transform) algorithm, to represent the spatial
derivatives in partial differential equations. Traditionally
the Fourier pseudospectral method is used only for spatially
periodic problems because the use of FFT implies
periodicity. In order to overcome this limitation, the
perfectly matched layer is used to attenuate the waves from
other periods, thus allowing the method to be applicable to
unbounded media. This new algorithm, referred to as the
pseudospectral time-domain (PSTD) algorithm, is developed to
solve large-scale problems for acoustic waves. It has an
infinite order of accuracy in the spatial derivatives, and
thus requires much fewer unknowns than the conventional FDTD
method. Numerical results confirms the efficacy of the PSTD
method. © 1998 IEEE.},
Doi = {10.1109/58.710587},
Key = {fds283791}
}
@article{fds283793,
Author = {Liu, QH and Tang, XY},
Title = {Iterative algorithm for nonuniform inverse fast Fourier
transform (NU-IFFT)},
Journal = {Electronics Letters},
Volume = {34},
Number = {20},
Pages = {1913-1914},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {1998},
Month = {October},
url = {http://dx.doi.org/10.1049/el:19981372},
Abstract = {A nonuniform inverse fast Fourier transform (NU-IFFT) for
nonuniformly sampled data is realised by combining the
conjugate-gradient fast Fourier transform (CG-FFT) method
with the newly developed nonuniform fast Fourier transform
(NUFFT) algorithms. An example application of the algorithm
in computational electromagnetics is presented.},
Doi = {10.1049/el:19981372},
Key = {fds283793}
}
@article{fds283792,
Author = {Chang, C and Liu, QH},
Title = {Inversion of source-time functions using borehole array
sonic waveforms},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {103},
Number = {6},
Pages = {3163-3168},
Publisher = {Acoustical Society of America (ASA)},
Year = {1998},
Month = {June},
url = {http://dx.doi.org/10.1121/1.423074},
Abstract = {Many geophysical applications of the array sonic
measurements require the knowledge of the true source-time
function. Recovery of the source-time function from the
borehole sonic P head waves is different from the source
inversion problem in exploration seismology. The difficulty
in the inversion of borehole sonic measurements arises due
to the inexact knowledge of the impulse response, e.g., the
inability to model the whole problem including the tool body
and transducers. The random noise often encountered in
seismic signals is not the key obstacle here. The inverse
source problem is ill posed due to the interference of P
head-wave multiples. Using waveforms from a laboratory scale
model we have applied two deconvolution methods, one using a
Wiener filter and the other the time-domain least-squares
method. As expected, without constraints on the solutions,
one cannot recover a satisfactory source-time function. An
unconventional smoothness constraint is applied in the
source spectrum (instead of the usual smoothness in the
time- domain signals), which corresponds to a
finite-duration pulse in the time domain (instead of the
usual band-limited spectrum). This technique is thus called
the 'duration-limited' inversion. The inverted results,
obtained by Wiener filtering combined with this 'duration
limiting' process and multichannel stacking, agree well with
an independent free-field measurement. Furthermore,
reconstructed receiver waveforms using the inverted source
function match the measured ones. The inversion procedure is
robust and potentially useful for field measurements.},
Doi = {10.1121/1.423074},
Key = {fds283792}
}
@article{fds283595,
Author = {Fan, GX and Liu, QH},
Title = {Dyadic Green's functions for curved waveguides and cavities
and their reformulation},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {3},
Pages = {1504-1507},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.690801},
Abstract = {The dyadic Green's functions (DGFs) for curved waveguides
and cavities are derived through a simple procedure, and
reformulated into a new form convenient for numerical
computation when both the source and field points are
located at the same waveguide wall. A general procedure for
reformulation of DGFs is proposed for general waveguides.
The DGFs derived can be used for solving the problems with
curved waveguide coupling and radiating slots, as well as
waveguide junction problems.},
Doi = {10.1109/APS.1998.690801},
Key = {fds283595}
}
@article{fds283596,
Author = {He, JQ and Liu, QH},
Title = {A nonuniform cylindrical fdtd aiborithm using new split PML
formulations},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {1},
Pages = {588-591},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.699208},
Abstract = {The perfectly rnatcheti layers (PML) was first introtlucetl
by Bereriger as a niaterial ab sorbing boundary conditions
(ABC) for electromagnetic waves [I]. It has been
clevelolietl widely for siiriiilatiori of wave propagation
and scattering in an iint)ounded rnediurri iu Cartesian
coordinates. Rigorous studies have been done on the PML for
nonorthogonal grids, notably 12-41, Most scherries do riot
admit cylindrical harmonics as the eigensolutions of the
iriodifictl Maxwell's equations. Only recently, several
foririiilations of PML ABCs have been irnplernerited in
cylindrical coordinates 15-91. In this work we show a
unified formulation to develop two PML ABCs wliicli split
Maxwell's equations in a form suitable for tirne-stepping. A
nonririiforin grid is used to implement FDTD algorithm for
inhomogemow conductive media in order to save computer
rnernory and coniputational time. Numerical results agree
well with arialytical solutions. Applications of the 3-D
algorithm are shown for borehole radar probing.},
Doi = {10.1109/APS.1998.699208},
Key = {fds283596}
}
@article{fds283597,
Author = {He, JQ and Liu, QH},
Title = {Nonuniform cylindrical FDTD algorithm with PML for borehole
radar modeling},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {1},
Pages = {285-287},
Year = {1998},
Month = {January},
Abstract = {Using the conventional finite-difference time-domain (FDTD)
method with a uniform Cartesian grid to simulate wave
propagation in media with cylindrical structures will cause
staircasing error. Furthermore, to accommodate the accurate
geometrical representation for both small and large
structures in a same problem, many unnecessary cells will be
wasted in the large region if the conventional uniform grid
is used. In order to avoid these two problems, a
three-dimensional FDTD algorithm with a nonuniform
cylindrical grid is developed for inhomogeneous conductive
media. Two modified perfectly matched layer (PML) absorbing
boundary conditions (ABCs) for cylindrical coordinates are
presented. The algorithm have been extensively validated.
Applications of this algorithm are shown for borehole radar
modeling.},
Key = {fds283597}
}
@article{6034123,
Author = {Liu, QH and Nguyen, N and Tang, XY},
Title = {Accurate algorithms for nonuniform fast forward and inverse
Fourier transforms and their applications},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {1},
Pages = {288-290},
Address = {Seattle, WA, USA},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/IGARSS.1998.702881},
Keywords = {fast Fourier transforms;matrix inversion;},
Abstract = {Regular fast Fourier transform (FFT) algorithms require
uniformly sampled data. In many practical situations,
however, the input data is nonuniform, and hence the regular
FFT does not apply. To overcome this difficulty we recently
proposed an accurate algorithm for the nonuniform forward
FFT (NUFFT) based on a new class of matrices, the regular
Fourier matrices. For the nonuniform inverse FFT (NU-IFFT)
algorithm, the conjugate-gradient method and the regular FFT
algorithm are combined to speed up a matrix inversion.
Numerical results show that thee algorithms are more than
one order of magnitude more accurate than existing
algorithms.},
Doi = {10.1109/igarss.1998.702881},
Key = {6034123}
}
@article{fds283599,
Author = {Liu, QH and Nguyen, N},
Title = {Nonuniform fast Fourier transform (NUFFT) algorithm and its
applications},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {3},
Pages = {1782-1785},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.690967},
Abstract = {Based on a class of regular Fourier matrices, a new
nonuniform fast Fourier transform (NUFFT) algorithm is
developed for unequally spaced data. With a comparable
complexity of O(N log2N), this algorithm is much more
accurate than previously reported results since it is
optimal in the least squares sense. The algorithm is useful
for computational electromagnetics and other fields of
applied mathematics.},
Doi = {10.1109/APS.1998.690967},
Key = {fds283599}
}
@article{fds283600,
Author = {Tang, XY and Liu, QH},
Title = {CG-FFT for nonuniform inverse fast Fourier transforms
(NU-IFFTs)},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {3},
Pages = {1786-1789},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.690969},
Abstract = {Based on the CG-FFT method and the NUFFT (nonuniform FFT)
algorithm, a new nonuniform inverse FFT (NU-IFFT) algorithm
is developed for nonuniform data. With a comparable
complexity of O(N log2N), this algorithm is much more
accurate than the previously reported results since it is
optimal in the least squares sense.},
Doi = {10.1109/APS.1998.690969},
Key = {fds283600}
}
@article{98094366489,
Author = {Liu, QH and Fan, GX},
Title = {PSTD algorithm for general dispersive media and its
applications to GPR simulations},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {1},
Pages = {207-209},
Address = {Seattle, WA, USA},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/IGARSS.1998.702854},
Keywords = {Time domain analysis;Algorithms;Computer
simulation;Electromagnetic dispersion;Partial differential
equations;Fast Fourier transforms;Spectrum
analysis;},
Abstract = {In this work we develop a pseudospectral time-domain (PSTD)
algorithm for the simulations of transient electromagnetic
waves in highly dispersive media. A general formulation is
proposed for arbitrary dispersion by expanding the
dispersion relation into a summation of simple poles. By
treating the spatial derivatives in the partial differential
equations with fast Fourier transform (FFT), orders of
magnitude reduction in the number of unknowns can be
achieved. The wraparound effect in the FFT is eliminated by
using the perfectly matched layer (PML) for dispersive
media.},
Key = {98094366489}
}
@article{fds283602,
Author = {Fan, GX and Liu, QH},
Title = {A PML-FDTD algorithm for general dispersive media in GPR and
plasma applications},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {4},
Pages = {2014-2017},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.701603},
Abstract = {We present a 3D FDTD algorithm with the PML absorbing
boundary condition for general inhomogeneous, dispersive,
conductive media. The modified time-domain Maxwell's
equations for dispersive media are expressed in terms of the
coordinate stretching variables. A single formulation is
developed to include recursive convolution and piecewise
linear recursive convolution for arbitrary dispersive media.
Several applications are demonstrated for subsurface radar
detection (GPR-ground penetrating radar) of cylinders and a
sphere buried in a dispersive half-space. The algorithm
proposed is ideal for parallel computation since the same
code is shared by both the interior computational region and
the outer matched layers. Because of their generality, the
algorithm and computer program developed can be used to
model biological materials, artificial dielectrics, optical
materials, and other dispersive media.},
Doi = {10.1109/APS.1998.701603},
Key = {fds283602}
}
@article{fds283603,
Author = {Tang, ZB and Liu, QH},
Title = {The 2.5D pseudospectral time-domain (PSTD) algorithm with
PML absorbing boundary condition},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {3},
Pages = {1496-1499},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.690798},
Abstract = {A 2.5-dimensional PSTD algorithm has been developed which
can be used to solve Maxwell's equations efficiently. The
code has been verified by the analytical results and the
conventional FDTD method. It is also shown that the 2.5D
PSTD algorithm is more efficient than the FDTD method.
Particularly, the 2.5D PSTD method can be used to model very
large objects because it needs a grid density of only 2
cell/λmin. The dispersion curve of an open dielectric
waveguide is obtained by using the 2.5D PSTD
algorithm.},
Doi = {10.1109/APS.1998.690798},
Key = {fds283603}
}
@article{fds283604,
Author = {Fan, GX and Liu, QH},
Title = {PML-FDTD algorithm for general dispersive
media},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {655-662},
Year = {1998},
Month = {January},
Abstract = {A three-dimensional (3D) finite-difference time-domain
(FDTD) algorithm with perfectly matched layer (PML)
absorbing boundary condition (ABC) is presented for general
inhomogeneous, dispersive, conductive media. The modified
time-domain Maxwell's equations for dispersive media are
expressed in terms of coordinate-stretching variables. The
recursive convolution (RC) and piecewise linear recursive
convolution (PLRC) approaches are extended to arbitrary
dispersive media in a more general form. The algorithm is
validated for homogeneous and inhomogeneous dispersive
media, and excellent agreement between the FDTD results and
analytical solutions is obtained with both RC and PLRC
approaches. We demonstrate the applications of the algorithm
by several examples in subsurface radar detection of
mine-like objects, cylinders and spheres buried in a
dispersive half-space, and a three-layer medium with a
dipping interface.},
Key = {fds283604}
}
@article{fds283605,
Author = {Liu, QH and He, JQ},
Title = {An efficient pstd algorithm in cylindrical
coordinates},
Journal = {Ieee Antennas and Propagation Society International
Symposium, 1998 Digest Antennas: Gateways to the Global
Network Held in Conjunction With: Usnc/Ursi National Radio
Science Meeting},
Volume = {1},
Pages = {558-561},
Publisher = {IEEE},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1998.699201},
Abstract = {The finite-difference time-domain (FDTD) method ha.7 been
enjoying its widespread applic:at,ions in the sirrnilat,ions
of transient electromagnctic wave propagation and scattoring
sincc it was first proposed by Yce in 19GG [l].Ifowever,as
the available computer niernory anti computational speed
grow rapidly so that unprecedented large-scale prohlerm can
bc solved, thc FDTD method starts to show its limitation
because of its relative large phase dispersion error.As the
problem size increases,so does the required number of
unknowns per wavelength.},
Doi = {10.1109/APS.1998.699201},
Key = {fds283605}
}
@article{fds283606,
Author = {He, JQ and Liu, QH},
Title = {Systematic study of three PML absorbing boundary conditions
through a unified formulation in cylindrical
coordinates},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {631-638},
Year = {1998},
Month = {January},
Abstract = {By using a unified formulation, we compare three perfectly
matched layer (PML) absorbing boundary conditions (ABC) in
two-dimensional polar coordinates. An improved scheme is
proposed to save the number of unknown field variables and
computation time. Two-dimensional polar FDTD algorithms are
developed to compare the effectiveness and efficiency of
these methods. Excellent agreement is found between
numerical results and analytical solutions. The formulation
is then extended to conductive media in full
three-dimensional cylindrical coordinates. We have developed
a 3-D nonuniform grid FDTD algorithm using one of these
formulations, the quasi-PML formulation, in cylindrical
coordinates. Applications of the 3-D program are
demonstrated for borehole radar probing.},
Key = {fds283606}
}
@article{fds283607,
Author = {Fan, GX and Liu, QH},
Title = {A PML-FDTD algorithm for simulating plasma-covered
cavity-backed slot antennas},
Journal = {Microwave and Optical Technology Letters},
Volume = {19},
Number = {4},
Pages = {258-262},
Publisher = {WILEY},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(199811)19:4<258::AID-MOP5>3.0.CO;2-J},
Abstract = {A three-dimensional frequency-dependent finite-difference
time-domain (FDTD) algorithm with perfectly matched layer
(PML) absorbing boundary condition (ABC) and recursive
convolution approaches is developed to model plasma-covered
open-ended waveguide or cavity-backed slot antennas. The
algorithm is validated and then applied to simulate the
radiation of an inhomogeneous plasma-covered cavity-backed
slot antenna. © 1998 John Wiley & Sons,
Inc.},
Doi = {10.1002/(SICI)1098-2760(199811)19:4<258::AID-MOP5>3.0.CO;2-J},
Key = {fds283607}
}
@article{fds283608,
Author = {Chen, YH and Chew, WC and Liu, QH},
Title = {A three-dimensional finite difference code for the modeling
of sonic logging tools},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {103},
Number = {2},
Pages = {702-712},
Publisher = {Acoustical Society of America (ASA)},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1121/1.421230},
Abstract = {This paper presents a numerical program for the simulation
of elastic wave propagation and scattering in
three-dimensional (3-D) cylindrical coordinates based on the
first-order velocity-stress finite-difference scheme on
staggered grids. Both Liao's and Lindman's absorbing
boundary conditions are implemented for the exterior
boundaries to efficiently truncate the computation domain
for elongated 3-D well logging problems. Symmetric and
anti-symmetric boundaries in azimuthal and axial directions
are also implemented in the code to further reduce the size
of the problem. Included for the first time with this code
are very large and complex geometrical structures such as
the whole slotted sleeve housing of a sonic well-logging
tool which typically involves hundreds of millions of
unknowns. The calculation for such a large problem only
takes a couple of days on a four- processor SGI Power
Challenge machine. Different types of slotted sleeve models
are studied for sonic logging tools. Simulation results show
that different slotted sleeves vary widely in delaying and
attenuating the pipe waves which travel along the tool
housing. A new slotted sleeve structure with three
horizontal slot sections for every vertical slot period is
proposed for better performance. A dipole source is found to
produce much cleaner waveforms than a monopole
source.},
Doi = {10.1121/1.421230},
Key = {fds283608}
}
@article{98014032925,
Author = {Liu, QH and Nguyen, N},
Title = {An accurate algorithm for nonuniform fast Fourier transforms
(NUFFT's)},
Journal = {Ieee Microwave and Guided Wave Letters},
Volume = {8},
Number = {1},
Pages = {18-20},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1998},
Month = {January},
ISSN = {1051-8207},
url = {http://dx.doi.org/10.1109/75.650975},
Keywords = {Fast Fourier transforms;Algorithms;Computational
complexity;Matrix algebra;Interpolation;},
Abstract = {Based on the (m, N, q)-regular Fourier matrix, a new
algorithm is proposed for fast Fourier transform (FFT) of
nonuniform (unequally spaced) data. Numerical results show
that the accuracy of this algorithm is much better than
previously reported results with the same computation
complexity of O(N log 2 N). Numerical examples are shown for
the applications in computational electromagnetics.},
Doi = {10.1109/75.650975},
Key = {98014032925}
}
@article{98074292428,
Author = {Liu, QH and Nguyen, N},
Title = {Accurate algorithm for nonuniform fast Fourier transforms
(NUFFT) and its applications},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {972-978},
Address = {Monterey, CA, USA},
Year = {1998},
Month = {January},
Keywords = {Algorithms;Fast Fourier transforms;Matrix
algebra;Computational complexity;Numerical
analysis;},
Abstract = {Based on the (m, N, q)-regular Fourier matrix, a new
algorithm is proposed for fast Fourier transform of
nonuniform (unequally spaced) data. Numerical results show
that the accuracy of this algorithm is much better than
previously reported results with the same computation
complexity of O(N log2N). Numerical examples are shown for
the applications in computational electromagnetics.},
Key = {98074292428}
}
@article{98104397082,
Author = {Liu, QH and He, JQ},
Title = {Quasi-PML for waves in cylindrical coordinates},
Journal = {Microwave and Optical Technology Letters},
Volume = {19},
Number = {2},
Pages = {107-111},
Year = {1998},
Month = {January},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(19981005)19:2<107::AID-MOP7>3.0.CO;2-K},
Keywords = {Electromagnetic wave transmission;Boundary conditions;Time
domain analysis;Finite difference method;Eigenvalues and
eigenfunctions;},
Abstract = {We prove that the straightforward extension of Berenger's
original perfectly matched layer (PML) is not reflectionless
at a cylindrical interface in the continuum limit. A
quasi-PLM is developed as an absorbing boundary condition
(ABC) for the finite-difference time-domain method in
cylindrical coordinates. For three-dimensional problems,
this quasi-PML requires only ten equations, instead of 12
equations in the best true PML formulations. With a
satisfactory absorption level, it is simpler, and requires
about 20% less computer memory than the true PML ABC. ©
1998 John Wiley & Sons, Inc.},
Doi = {10.1002/(SICI)1098-2760(19981005)19:2<107::AID-MOP7>3.0.CO;2},
Key = {98104397082}
}
@article{98074292412,
Author = {Liu, QH},
Title = {On the PSTD method for large-scale problems},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {852-857},
Address = {Monterey, CA, USA},
Year = {1998},
Month = {January},
Keywords = {Algorithms;Finite difference method;Spectrum analysis;Fast
Fourier transforms;Problem solving;},
Abstract = {Conventional finite-difference time-domain (FDTD) methods
require a large number of unknowns, typically 10-20 nodes
per minimum wavelength λ for a problem of medium size. This
work makes a theoretical comparison of the pseudospectral
time-domain (PSTD) method with the FDTD and MRTD
(multi-resolution time-domain) methods. The new PSTD
algorithm is based on the fast Fourier transforms and
perfectly matched layers. It significantly reduces the
number of unknowns to 2 nodes/λ. The method is demonstrated
by a three-dimensional problem with an apparently
unprecedented size of 128λ×128λ×128λ.},
Key = {98074292412}
}
@article{98074292411,
Author = {Liu, QH and He, JQ},
Title = {PSTD algorithm in cylindrical coordinates},
Journal = {Annual Review of Progress in Applied Computational
Electromagnetics},
Volume = {2},
Pages = {845-851},
Address = {Monterey, CA, USA},
Year = {1998},
Month = {January},
Keywords = {Finite difference method;Time domain analysis;Convergence of
numerical methods;Spectrum analysis;Maxwell
equations;Problem solving;Algorithms;},
Abstract = {The finite-difference time-domain (FDTD) method is a
powerful numerical technique for transient solutions of
electromagnetic waves. When applied to cylindrical
coordinates in a straightforward way, however, it is limited
by the contradictory requirements for accuracy and for
numerical stability. These limitations arise because of the
nonuniform distribution of cells in the computational
domain. Moreover, the staggered grid encounters a
singularity problem at the origin. We proposed a new
pseudospectral time-domain (PSTD) method for the solution of
Maxwell's equations in cylindrical coordinates. It
eliminates the singularity problem by using a centered grid.
Because of its high accuracy in the spatial derivatives, the
PSTD method can employ a much larger cell and time step,
making the algorithm far more efficient than the FDTD
method.},
Key = {98074292411}
}
@article{6115862,
Author = {Liu, Q.H. and He, J.Q.},
Title = {Quasi-PML for waves in cylindrical coordinates},
Journal = {Microw. Opt. Technol. Lett. (USA)},
Volume = {19},
Number = {2},
Pages = {107 - 11},
Year = {1998},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(19981005)19:2<107::AID-MOP7>3.0.CO;2-K},
Keywords = {electromagnetic wave absorption;finite difference
time-domain analysis;},
Abstract = {We prove that the straightforward extension of Berenger's
original perfectly matched layer (PML) is not reflectionless
at a cylindrical interface in the continuum limit. A
quasi-PML is developed as an absorbing boundary condition
(ABC) for the finite-difference time-domain method in
cylindrical coordinates. For three-dimensional problems,
this quasi-PML requires only ten equations, instead of
twelve equations in the best true PML formulations. With a
satisfactory absorption level, it is simpler and requires
about 20% less computer memory than the true PML
ABC},
Key = {6115862}
}
@article{6141910,
Author = {Fan, G.-X. and Liu, Q.H.},
Title = {A PML-FDTD algorithm for general dispersive media in GPR and
plasma applications},
Journal = {IEEE Antennas and Propagation Society International
Symposium. 1998 Digest. Antennas: Gateways to the Global
Network. Held in conjunction with: USNC/URSI National Radio
Science Meeting (Cat. No.98CH36194)},
Volume = {vol.4},
Pages = {2014 - 17},
Address = {Atlanta, GA, USA},
Year = {1998},
url = {http://dx.doi.org/10.1109/APS.1998.701603},
Keywords = {antennas in plasma;buried object detection;convolution;dispersive
media;electromagnetic wave absorption;electromagnetic wave
propagation;finite difference time-domain
analysis;inhomogeneous media;Maxwell equations;radar
detection;slot antennas;time-domain analysis;},
Abstract = {We present a 3D FDTD algorithm with the PML absorbing
boundary condition for general inhomogeneous, dispersive,
conductive media. The modified time-domain Maxwell's
equations for dispersive media are expressed in terms of the
coordinate stretching variables. A single formulation is
developed to include recursive convolution and piecewise
linear recursive convolution for arbitrary dispersive media.
Several applications are demonstrated for subsurface radar
detection (GPR-ground penetrating radar) of cylinders and a
sphere buried in a dispersive half-space. The algorithm
proposed is ideal for parallel computation since the same
code is shared by both the interior computational region and
the outer matched layers. Because of their generality, the
algorithm and computer program developed can be used to
model biological materials, artificial dielectrics, optical
materials, and other dispersive media},
Key = {6141910}
}
@article{98094366516,
Author = {Liu, Q.H. and Nguyen, N. and Tang, X.Y.},
Title = {Accurate algorithms for nonuniform fast forward and inverse
Fourier transforms and their applications},
Journal = {International Geoscience and Remote Sensing Symposium
(IGARSS)},
Volume = {1},
Pages = {288 - 290},
Address = {Seattle, WA, USA},
Year = {1998},
url = {http://dx.doi.org/10.1109/IGARSS.1998.702881},
Keywords = {Fast Fourier transforms;Matrix algebra;Interpolation;Algorithms;},
Abstract = {Regular fast Fourier transform (FFT) algorithms require
uniformly sampled data. In many practical situations,
however, the input data is nonuniform, and hence the regular
FFT does not apply. To overcome this difficulty we recently
proposed an accurate algorithm for the nonuniform forward
FFT (NUFFT) based on a new class of matrices, the regular
Fourier matrices. For the nonuniform inverse FFT (NU-IFFT)
algorithm, the conjugate-gradient method and the regular FFT
algorithm are combined to speed up a matrix inversion.
Numerical results show that thee algorithms are more than
one order of magnitude more accurate than existing
algorithms.},
Key = {98094366516}
}
@article{6034099,
Author = {Liu, Q.H. and Fan, G.-X.},
Title = {A PSTD algorithm for general dispersive media and its
applications to GPR simulations},
Journal = {IGARSS '98. Sensing and Managing the Environment. 1998 IEEE
International Geoscience and Remote Sensing. Symposium
Proceedings. (Cat. No.98CH36174)},
Volume = {vol.1},
Pages = {207 - 9},
Address = {Seattle, WA, USA},
Year = {1998},
url = {http://dx.doi.org/10.1109/IGARSS.1998.702854},
Keywords = {geophysical prospecting;geophysical techniques;radar
applications;radar cross-sections;radar theory;remote
sensing by radar;terrestrial electricity;},
Abstract = {The authors develop a pseudospectral time-domain (PSTD)
algorithm for the simulations of transient electromagnetic
waves in highly dispersive media. A general formulation is
proposed for arbitrary dispersion by expanding the
dispersion relation into a summation of simple poles. By
treating the spatial derivatives in the partial differential
equations with fast Fourier transform (FFT), orders of
magnitude reduction in the number of unknowns can be
achieved. The wraparound effect in the FFT is eliminated by
using the perfectly matched layer (PML) for dispersive
media},
Key = {6034099}
}
@article{5808856,
Author = {Liu, QH and Li, YL and Liao, JC},
Title = {PSTD algorithm: A fast and accurate time-domain method for
electronic package characterization},
Journal = {Ieee Topical Meeting on Electrical Performance of Electronic
Packaging},
Pages = {149-152},
Publisher = {IEEE},
Address = {San Jose, CA, USA},
Year = {1997},
Month = {December},
url = {http://dx.doi.org/10.1109/EPEP.1997.634059},
Keywords = {electromagnetic interference;packaging;spectral-domain
analysis;time-domain analysis;},
Abstract = {Conventional finite-difference time-domain (FDTD) methods
are very inefficient for simulations of electromagnetic wave
propagation in large-scale complex media. This is mainly
because of the low-accuracy associated with the spatial
discretization in the FDTD methods. As a result, even for a
moderate size problem, a large number of cells (typically
10-20 cells per wavelength) are required to obtain
reasonably accurate results. This requirement becomes much
more stringent for large-scale problems since the dispersion
error grows rapidly with the propagation distance. Recently
a pseudospectral time-domain (PSTD) algorithm has been
developed which requires only two cells per wavelength
regardless of the problem size. In terms of spatial
discretization, this method is an optimal time-domain
solution since it has an infinite order of accuracy in the
spatial representation. For a problem with structures much
smaller than the smallest wavelength, the PSTD algorithm
still provides high accuracy up to a much higher spatial
frequency than FDTD methods. In addition, the only error
introduced in the PSTD algorithm is the temporal
discretization. Unlike the dispersion error in FDTD methods,
this error is isotropic and does not increase with the scale
of the problem. In this work, we apply the PSTD method to
characterize the electrical performance of electronic
packages. In particular, it is used to investigate the
effects of enclosure resonance and electromagnetic
interference.},
Doi = {10.1109/epep.1997.634059},
Key = {5808856}
}
@article{fds283593,
Author = {Liu, QH and Tao, J},
Title = {The perfectly matched layer for acoustic waves in absorptive
media},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {102},
Number = {4},
Pages = {2072-2082},
Publisher = {Acoustical Society of America (ASA)},
Year = {1997},
Month = {October},
ISSN = {0001-4966},
url = {http://dx.doi.org/10.1121/1.419657},
Abstract = {The perfectly matched layer (PML) was first introduced by
Berenger as a material absorbing boundary condition (ABC)
for electromagnetic waves. It was first proven by Chew and
Liu that a fictitious elastic PML half-space also exists in
solids, which completely absorbs elastic waves, in spite of
the coupling between compressional and shear waves. The PML
absorbing boundary condition provides much higher absorption
than other previous ABCs in finite- difference methods. In
this work, a method is presented to extend the perfectly
matched layer to simulating acoustic wave propagation in
absorptive media. This nonphysical material is used at the
computational edge of a finite-difference time-domain (FDTD)
algorithm as an ABC to truncate unbounded media. Two aspects
of the acoustic PML are distinct: (a) For a perfectly
matched layer in an intrinsically absorptive medium, an
additional term involving the time-integrated pressure field
has to be introduced to account for the coupling between the
loss from the PML and the normal absorptive loss; (b) In
contrast to the full elastodynamic problem, the acoustic PML
requires a splitting only on the pressure field, but not on
the particle velocity field. The FDTD algorithm is validated
by analytical solutions and other numerical results for two-
and three-dimensional problems. Unlike the previous ABCs,
the PML ABC effectively absorbs outgoing waves at the
computational edge even when a dipping interface intersects
the outer boundary.},
Doi = {10.1121/1.419657},
Key = {fds283593}
}
@article{97063686547,
Author = {Liu, QH},
Title = {The PSTD algorithm: A time-domain method requiring only two
cells per wavelength},
Journal = {Microwave and Optical Technology Letters},
Volume = {15},
Number = {3},
Pages = {158-165},
Year = {1997},
Month = {June},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(19970620)15:3<158::AID-MOP11>3.0.CO;2-3},
Keywords = {Maxwell equations;Fast Fourier transforms;Time domain
analysis;Algorithms;Finite difference method;Conductive
materials;Electromagnetic wave scattering;},
Abstract = {A pseudospectral time-domain (PSTD) method is developed for
solutions of Maxwell's equations. It uses the fast Fourier
transform (FFT), instead of finite differences in
conventional finite-difference-time-domain (FDTD) methods,
to represent spatial derivatives. Because the Fourier
transform has an infinite order of accuracy, only two cells
per wavelength are required, compared to 8-16 cells per
wavelength required by the FDTD method for the same
accuracy. The wraparound effect, a major limitation caused
by the periodicity assumed in the FFT, is removed by using
Berenger's perfectly matched layers. The PSTD method is a
factor of 4D-8D more efficient than the FDTD methods (D is
the dimensionality). © 1997 John Wiley & Sons,
Inc.},
Doi = {10.1002/(SICI)1098-2760(19970620)15:3<158::AID-MOP11>3.0.CO;},
Key = {97063686547}
}
@article{97103904170,
Author = {Liu, QH},
Title = {Finite-difference and pseudospectral time-domain methods for
subsurface radar applications},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {2},
Pages = {990-993},
Address = {Montreal, Can},
Year = {1997},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1997.631694},
Keywords = {Finite difference method;Time domain analysis;Radar
measurement;Approximation theory;Algorithms;Fast Fourier
transforms;},
Abstract = {The development and capabilities in the simulations of
subsurface radar applications of finite difference time
domain (FDTD) and pseudospectral time domain (PSTD) methods
are compared. Numerical examples demonstrate their relative
accuracy and efficiency for different problems.},
Key = {97103904170}
}
@article{5745327,
Author = {Liu, QH},
Title = {Using GPR and seismic reflection measurements to
characterize buried objects: Large-scale
simulations},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {3},
Pages = {1147-1149},
Address = {Singapore},
Year = {1997},
Month = {January},
url = {http://dx.doi.org/10.1109/IGARSS.1997.606379},
Keywords = {finite difference time-domain analysis;geophysical
techniques;numerical analysis;radar detection;radar
theory;remote sensing by radar;seismology;terrestrial
electricity;},
Abstract = {The pseudospectral time-domain (PSTD) method and the
finite-difference time-domain (FDTD) method were used to
perform large-scale simulations of ground penetrating radar
(GPR) and seismic reflection measurements. The PSTD method
uses the fast Fourier transform together with the perfectly
matched layer to solve the partial differential equations.
It requires only two cells per wavelength regardless of the
problem size. For multidimensional problems, the PSDT method
is 4D-32D times more efficient than the conventional FDTD
method. Hence, the PSTD algorithm is ideal for large scale
problems. The FDTD is used to model structures with fine
details below 1/8 wavelength. Both the FDTD and PSTD
algorithms are developed for conductive and viscous
media.},
Key = {5745327}
}
@article{97103901822,
Author = {Liu, QH},
Title = {New numerical method for large-scale complex media: The PSTD
algorithm},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {2},
Pages = {942-944},
Address = {Singapore, Singapore},
Year = {1997},
Month = {January},
url = {http://dx.doi.org/10.1109/IGARSS.1997.615304},
Keywords = {Algorithms;Time domain analysis;Numerical methods;Large
scale systems;},
Abstract = {Conventional finite-difference time-domain (FDTD) methods
are very inefficient for simulations of electromagnetic wave
propagation in large-scale complex media. This is mainly
because of the low-accuracy associated with the spatial
discretization in the FDTD methods. As a result, even for a
moderate size problem, a large number of cells (typically
10-20 cells per wavelength) are required to obtain
reasonably accurate results. This requirement becomes much
more stringent for large-scale problems since the dispersion
error grows rapidly with the propagation distance. We
recently developed a pseudospectral time-domain (PSTD)
method which requires only two cells per wavelength
regardless of the problem size. In terms of the spatial
discretization, this method is an optimal time-domain
solution since it has an infinite order of accuracy in the
spatial representation. For a problem of size 32 to 512
wavelengths in each dimension, the PSTD method is at least
4D-32D times more efficient than the FDTD method (where D is
the dimensionality of the problem). For larger problems, the
advantage of the PSTD method becomes even more profound.
Therefore, the PSTD method is ideal for simulations of
electromagnetic wave propagation in large-scale complex
media.},
Key = {97103901822}
}
@article{fds283592,
Author = {Liu, QH},
Title = {Pseudospectral time-domain (PSTD) method: A new algorithm
for solutions of Maxwell's equations},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {122-124},
Year = {1997},
Month = {January},
Abstract = {A pseudospectral time-domain (PSTD) algorithm was developed
to simulate electromagnetic waves in inhomogeneous,
conductive media. It requires only two grids per wavelength
because the Fourier transform is used to represent spatial
derivatives. The wraparound effect caused by the use of fast
Fourier transform (FFT) is eliminated by using Berenger's
perfectly matched layers (PML). For the same accuracy in the
PSTD method with two grids per wavelength, the Yee's FDTD
algorithm requires 8-16 grids per wavelength. Hence, the
PSTD method is 4D-8D times more efficient than FDTD
methods.},
Key = {fds283592}
}
@article{5815992,
Author = {Liu, Q.H.},
Title = {The pseudospectral time-domain (PSTD) method: a new
algorithm for solutions of Maxwell's equations},
Journal = {IEEE Antennas and Propagation Society International
Symposium 1997. Digest (Cat. No.97CH36122)},
Volume = {vol.1},
Pages = {122 - 5},
Address = {Montreal, Que., Canada},
Year = {1997},
url = {http://dx.doi.org/10.1109/APS.1997.630102},
Keywords = {dispersion (wave);electromagnetic wave propagation;fast
Fourier transforms;Maxwell equations;parallel
algorithms;time-domain analysis;},
Abstract = {We have developed a pseudospectral time-domain (PSTD)
algorithm to simulate electromagnetic waves in
inhomogeneous, conductive media. It requires only two grids
per wavelength because the Fourier transform (through an FFT
algorithm) is used to represent spatial derivatives. The
wrap-around effect caused by the use of FFT is eliminated by
using Berenger's perfectly matched layers (PML). Numerical
experiments show that for the same accuracy in the PSTD
method with two grids per wavelength, Yee's FDTD algorithm
requires 8-16 grids per wavelength. Hence, the PSTD method
is 4<sup>D</sup>-8<sup>D</sup> times more efficient than
FDTD methods (D is the dimensionality of the problem). The
PSTD method is ideal for parallel computation of large-scale
problems since both the FFT and the PML are well-suited for
parallelization},
Key = {5815992}
}
@article{5822289,
Author = {Liu, Q.H.},
Title = {Finite-difference and pseudospectral time-domain methods for
subsurface radar applications},
Journal = {IEEE Antennas and Propagation Society International
Symposium 1997. Digest (Cat. No.97CH36122)},
Volume = {vol.2},
Pages = {990 - 3},
Address = {Montreal, Que., Canada},
Year = {1997},
url = {http://dx.doi.org/10.1109/APS.1997.631694},
Keywords = {electromagnetic wave propagation;fast Fourier
transforms;finite difference time-domain analysis;Maxwell
equations;radar applications;radiowave propagation;spectral-domain
analysis;},
Abstract = {The finite-difference time-domain (FDTD) method is widely
applied to simulate transient electromagnetic wave
propagation. In this method, the spatial and temporal
derivatives in Maxwell's equations are approximated by
finite differences. Numerical experiments show that accurate
results require a fine discretization of about 8-20 grids
per wavelength at the highest frequency being simulated. To
increase the efficiency of time-domain solutions, various
spectral-domain techniques have been developed to reduce the
grid density. In particular, the pseudospectral time-domain
(PSTD) method uses a fast Fourier transform (FFT) algorithm
to represent the spatial derivatives in Maxwell's equations,
and provides accurate results with only two grids per
wavelength. This article compares the FDTD and PSTD methods
in terms of their development and capabilities in the
simulations of subsurface radar applications. Numerical
examples are used to demonstrate their relative accuracy and
efficiency for different problems},
Key = {5822289}
}
@article{5724155,
Author = {Liu, Q.H.},
Title = {A new numerical method for large-scale complex media: the
PSTD algorithm},
Journal = {IGARSS'97. 1997 International Geoscience and Remote Sensing
Symposium. Remote Sensing - A Scientific Vision for
Sustainable Development (Cat. No.97CH36042)},
Volume = {vol.2},
Pages = {942 - 4},
Address = {Singapore},
Year = {1997},
url = {http://dx.doi.org/10.1109/IGARSS.1997.615304},
Keywords = {difference equations;finite element analysis;geophysical
techniques;radar cross-sections;radar theory;remote sensing
by radar;terrestrial electricity;},
Abstract = {Conventional finite-difference time-domain (FDTD) methods
are very inefficient for simulations of electromagnetic wave
propagation in large-scale complex media. This is mainly
because of the low-accuracy associated with the spatial
discretization in the FDTD methods. As a result, even for a
moderate size problem, a large number of cells (typically
10-20 cells per wavelength) are required to obtain
reasonably accurate results. This requirement becomes much
more stringent for large-scale problems since the dispersion
error grows rapidly with the propagation distance. The
authors recently developed a pseudospectral time-domain
(PSTD) method which requires only two cells per wavelength
regardless of the problem size. In terms of the spatial
discretization, this method is an optimal time-domain
solution since it has an infinite order of accuracy in the
spatial representation. For a problem of size 32 to 512
wavelengths in each dimension, the PSTD method is at least
4<sup>D</sup>-32<sup>D</sup> times more efficient than the
FDTD method (where D is the dimensionality of the problem).
For larger problems, the advantage of the PSTD method
becomes even more profound. Therefore, the PSTD method is
ideal for simulations of electromagnetic wave propagation in
large-scale complex media},
Key = {5724155}
}
@article{5634386,
Author = {Liu, Q.H.},
Title = {The PSTD algorithm: a time-domain method requiring only two
cells per wavelength},
Journal = {Microw. Opt. Technol. Lett. (USA)},
Volume = {15},
Number = {3},
Pages = {158 - 65},
Year = {1997},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(19970620)15:3<158::AID-MOP11>3.0.CO;2-3},
Keywords = {electromagnetic wave propagation;fast Fourier
transforms;Maxwell equations;spectral-domain
analysis;time-domain analysis;},
Abstract = {A pseudospectral time-domain (PSTD) method is developed for
solutions of Maxwell's equations. It uses the fast Fourier
transform (FFT), instead of finite differences in
conventional finite-difference-time-domain (FDTD) methods,
to represent spatial derivatives. Because the Fourier
transform has an infinite order of accuracy, only two cells
per wavelength are required, compared to 8-16 cells per
wavelength required by the FDTD method for the same
accuracy. The wraparound effect, a major limitation caused
by the periodicity assumed in the FFT, is removed by using
Berenger's (see J. Comput. Phys., vol.114, p.185-200, 1994)
perfectly matched layers. The PSTD method is a factor of
4<sup>D</sup>-8<sup>D</sup> more efficient than the FDTD
methods (D is the dimensionality)},
Key = {5634386}
}
@article{5511284,
Author = {Liu, QH},
Title = {An FDTD algorithm with perfectly matched layers for
conductive media},
Journal = {Microwave and Optical Technology Letters},
Volume = {14},
Number = {2},
Pages = {134-137},
Year = {1997},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(19970205)14:2<134::AID-MOP17>3.0.CO;2-B},
Keywords = {electromagnetic wave absorption;electromagnetic wave
scattering;finite difference time-domain
analysis;losses;Maxwell equations;},
Abstract = {We extend Berenger's perfectly matched layers (PML) to
conductive media. A finite-difference-time-domain (FDTD)
algorithm with PML as an absorbing boundary condition is
developed for solutions of Maxwell's equations in
inhomogeneous, conductive media. For a perfectly matched
layer in a conductive medium, an additional term involving
the time-integrated electric field has to be introduced to
account for the coupling between the loss from the PML and
the normal conduction loss. This absorbing boundary
condition is proven to be highly effective for the
absorption of outgoing waves at the computational edge even
when a dipping interface intersects the outer boundary. The
algorithm is validated by analytical solutions, and is also
compared with Liao's absorbing boundary condition. Numerical
results for subsurface radar measurements are shown to
demonstrate the applications of this method. © 1997 John
Wiley & Sons, Inc.},
Key = {5511284}
}
@article{97023511757,
Author = {Liu, QH},
Title = {FDTD algorithm with perfectly matched layers for conductive
media},
Journal = {Microwave and Optical Technology Letters},
Volume = {14},
Number = {2},
Pages = {134-137},
Publisher = {WILEY},
Year = {1997},
url = {http://dx.doi.org/10.1002/(SICI)1098-2760(19970205)14:23.0.CO;2-B},
Keywords = {Algorithms;Finite difference method;Time domain
analysis;Boundary conditions;Electromagnetic wave
absorption;Electromagnetic wave scattering;Radar;Maxwell
equations;Electric fields;},
Abstract = {We extend Berenger's perfectly matched layers (PML) to
conductive media. A finite-difference-time-domain (FDTD)
algorithm with PML as an absorbing boundary condition is
developed for solutions of Maxwell's equations in
inhomogeneous, conductive media. For a perfectly matched
layer in a conductive medium, an additional term involving
the time-integrated electric field has to be introduced to
account for the coupling between the loss from the PML and
the normal conduction loss. This absorbing boundary
condition is proven to be highly effective for the
absorption of outgoing waves at the computational edge even
when a dipping interface intersects the outer boundary. The
algorithm is validated by analytical solutions, and is also
compared with Liao's absorbing boundary condition. Numerical
results for subsurface radar measurements are shown to
demonstrate the applications of this method.},
Doi = {10.1002/(SICI)1098-2760(19970205)14:23.0.CO;2-B},
Key = {97023511757}
}
@article{5473404,
Author = {Chew, WC and Liu, QH},
Title = {Perfectly matched layers for elastodynamics: A new absorbing
boundary condition},
Journal = {Journal of Computational Acoustics},
Volume = {4},
Number = {4},
Pages = {341-359},
Publisher = {World Scientific Pub Co Pte Lt},
Year = {1996},
Month = {December},
url = {http://dx.doi.org/10.1142/S0218396X96000118},
Keywords = {elastic waves;finite difference methods;parallel
algorithms;partial differential equations;physics
computing;},
Abstract = {The use of perfectly matched layers (PML) has recently been
introduced by Berenger as a material absorbing boundary
condition (ABC) for electromagnetic waves. In this paper, we
will first prove that a fictitious elastodynamic material
half-space exists that will absorb an incident wave for all
angles and all frequencies. Moreover, the wave is
attenuative in the second half-space. As a consequence,
layers of such material could be designed at the edge of a
computer simulation region to absorb outgoing waves. Since
this is a material ABC, only one set of computer codes is
needed to simulate an open region. Hence, it is easy to
parallelize such codes on multiprocessor computers. For
instance, it is easy to program massively parallel computers
on the SIMD (single instruction multiple data) mode for such
codes. We will show two- and three-dimensional computer
simulations of the PML for the linearized equations of
elastodynamics. Comparison with Liao's ABC will be
given.},
Doi = {10.1142/S0218396X96000118},
Key = {5473404}
}
@article{fds283588,
Author = {Liu, QH and Schoen, E and Daube, F and Randall, C and Liu, HL and Lee,
P},
Title = {A three-dimensional finite difference simulation of sonic
logging},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {100},
Number = {1},
Pages = {72-79},
Publisher = {Acoustical Society of America (ASA)},
Year = {1996},
Month = {July},
ISSN = {0001-4966},
url = {http://dx.doi.org/10.1121/1.415869},
Abstract = {A three-dimensional finite-difference (FD) method is used to
simulate sonic wave propagation in a borehole with an
inhomogeneous solid formation. The second-order FD scheme
solves the first-order elastic wave equations with central
differencing in both space and time via staggered grids.
Liao's boundary condition is used to reduce artificial
reflections from the finite computational domain. In the
staggered grids, sources have to be implemented at the
discrete center in order to maintain the appropriate
symmetry in an axisymmetric borehole environment. The FD
scheme is validated for multipole sources in three special
media: (i) a homogeneous medium; (ii) a homogeneous
formation with a fluid-filled borehole; and (iii) a
horizontally layered formation. The staircase approximation
of a circular borehole introduces little error in dipole
wave fields, although it causes a noticeable phase velocity
error in the monopole Stoneley wave. This error has been
drastically reduced by using a material averaging scheme and
finer grids. Numerical examples show that the FD scheme can
accurately model 3-D elastic wave propagation in complex
borehole environments.},
Doi = {10.1121/1.415869},
Key = {fds283588}
}
@article{fds283585,
Author = {Sinha, BK and Liu, QH and Kostek, S},
Title = {Acoustic waves in pressurized boreholes: A finite difference
formulation},
Journal = {Journal of Geophysical Research: Solid Earth},
Volume = {101},
Number = {B11},
Pages = {25173-25180},
Publisher = {American Geophysical Union (AGU)},
Year = {1996},
Month = {January},
url = {http://dx.doi.org/10.1029/96jb02724},
Abstract = {A velocity-stress, finite difference formulation of acoustic
waves in a fluid-filled, pressurized borehole yields
synthetic waveforms for monopole or dipole sources before
and after borehole pressurization. Processing of these
waveforms using a variation of Prony's procedure isolates
dominant arrivals in the full wave field. Differences
between the slownesses of individual arrivals before and
after pressurization provide stress-induced changes in
propagation characteristics that are of importance in
estimating mechanical properties of the formation. The
borehole pressurization in an isotropic formation produces
insignificant changes in the compressional head wave
slownesses; and small changes in the shear head wave
slownesses. The most significant changes occur in the
Stoneley and flexural slownesses at relatively higher
frequencies in the range of 5-10 kHz for a borehole of
diameter 20.32 cm (8 inches). These differences in the
Stoneley and flexural slowness dispersions for a known
increase in the borehole pressure can be used to calculate
the acoustoelastic coefficients of the formation. These
coefficients are measures of nonlinear elastic parameters of
the formation that are generally larger for poorly
consolidated slow formations than those of tightly
consolidated fast formations. Copyright 1996 by the American
Geophysical Union.},
Doi = {10.1029/96jb02724},
Key = {fds283585}
}
@article{5507248,
Author = {Chew, WC and Liu, QH},
Title = {Using perfectly matched layers for elastodynamics},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {366-369},
Address = {Baltimore, MD, USA},
Year = {1996},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1996.549614},
Keywords = {elastic waves;geophysical prospecting;geophysical
techniques;nondestructive testing;seismic
waves;},
Abstract = {This paper proves that a perfectly matched interface exists
for linearized elastodynamics. This is easily done from the
viewpoint of a stretched coordinate system. It also shows
how the equations of motion could be split in the time
domain in order to incorporate this effect in the time
domain. This perfectly matched interface can be used to make
perfectly matched layers as absorbers in numerical
simulations to emulate an infinite region.},
Key = {5507248}
}
@article{fds283587,
Author = {Liu, QH and Chang, C},
Title = {Compressional head waves in attenuative formations: Forward
modeling and inversion},
Journal = {Geophysics},
Volume = {61},
Number = {6},
Pages = {1908-1920},
Publisher = {Society of Exploration Geophysicists},
Year = {1996},
Month = {January},
url = {http://dx.doi.org/10.1190/1.1444106},
Abstract = {We develop a method of forward modeling and inverting
formation attenuation data from sonic compressional head
waves in a fluid-filled borehole using a branch-cut
integration (BCI) technique to calculate individual acoustic
arrivals. We validate this approach with a real-axis
integration (RAI) method that does not separate the
individual arrivals. We show that the straightforward
application of the original BCI method for lossless media
gives erroneous results for attenuative formations. With a
choice of the Riemann sheets satisfying the radiation
condition, the new BCI method gives correct results for most
lossy and lossless formations. However, modeling very slow
formations needs to include the contribution of a leaky pole
near the vertical branch cut. With a constant-Q assumption,
we develop a simple processing scheme to extract the
formation compressional Q factor from the P head-wave
arrivals. We used experimental data from laboratory-scale
borehole measurements to invert for the compressional Q
value of a Lucite block. The inverted results agree within
4.5% of an independent ultrasonic transmission measurement
of Q.},
Doi = {10.1190/1.1444106},
Key = {fds283587}
}
@article{fds283584,
Author = {Lu, CC and Liu, QH},
Title = {A three-dimensional dyadic Green's function for elastic
waves in multilayer cylindrical structures},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {98},
Number = {5},
Pages = {2825-2835},
Publisher = {Acoustical Society of America (ASA)},
Year = {1995},
Month = {January},
ISSN = {0001-4966},
url = {http://dx.doi.org/10.1121/1.413248},
Abstract = {The three-dimensional dyadic Green's function for multilayer
cylindrical structures is very important for solutions of
elastic waves with arbitrary sources in such media. Both the
primary and reflected parts of this Green's function are
expressed as a Fourier integral in z (axial coordinate) and
a Fourier series in 0 (azimuthal coordinate). In this
spectral domain, the reflection matrices can be found
recursively by using the boundary conditions at the layer
interfaces. Inverse transforming this solution yields the
dyadic Green's function in the spatial domain. The Green's
function derived and implemented is applicable to arbitrary
cylindrically layered media, including three types of
interfaces: (i) fluid/solid interfaces, (ii) well-bonded
solid/solid interfaces, and (iii) unbonded solid/ solid
interfaces. Various numerical results from previous methods
for simpler cases and several specially designed simulations
validate the numerical implementation. With the Green's
function, one can solve for fields due to an arbitrary
source located at an arbitrary position using the
superposition principle. This provides a powerful tool for
the modeling of effects from defects and material
inhomogeneities in cylindrical structures. © 1995,
Acoustical Society of America. All rights
reserved.},
Doi = {10.1121/1.413248},
Key = {fds283584}
}
@article{95032644440,
Author = {Liu, QH},
Title = {Generalization of the k-space formulation to elastodynamic
scattering problems},
Journal = {The Journal of the Acoustical Society of
America},
Volume = {97},
Number = {3},
Pages = {1373-1379},
Publisher = {Acoustical Society of America (ASA)},
Year = {1995},
Month = {January},
ISSN = {0001-4966},
url = {http://dx.doi.org/10.1121/1.412079},
Abstract = {A generalized k-space (GKS) formulation is presented for
vectorial elastodynamic scattering problems. It represents a
generalization of Bojarski's scalar k-space formulation.
From the basic second-order partial differential equation or
its integral representation in the space-frequency (r-f)
domain, a local equation is derived for the displacement
field in the spectral-frequency (k-f) domain. This equation,
together with the constitutive equation in the r-f domain,
reduces the original scattering problem into two
simultaneous local equations with two unknowns (displacement
field and the induced source), which are then solved by the
conjugate-gradient (CG) method. The connection between the
k-f domain and r-f domain is obtained by the spatial fast
Fourier transform (FFT) algorithm. The number of complex
multiply-add operations per CG iteration is O(N log2N), and
the storage requirement is only O(N), where N is the number
of spatial discretization points. This is much more
efficient than the conventional method of moment combined
with the CG procedures which requires O(N2) operations per
iteration and O(N2) storage. In the spectral-time (k-t)
domain, however, it is found that four simultaneous local
equations have to be used to formulate the k-space algorithm
because of the existence of two wave speeds. By virtue of
the causality, a new local time-stepping algorithm is
derived with the aid of two temporal propagators, i.e., the
compressional and shear propagators. The connection between
the r-t domain and k-t domain is again obtained by the
spatial FFT algorithm. Therefore, in each time step, the
number of complex multiply-add operations is O(N log2 N),
and the storage requirement is O(N). Most importantly, for
the same accuracy, N can be much smaller than that for the
conventional finite-difference method.© 1995, Acoustical
Society of America. All rights reserved.},
Doi = {10.1121/1.412079},
Key = {95032644440}
}
@article{fds283580,
Author = {Liu, QH and Anderson, B and Chew, WC},
Title = {Modeling Low-Frequency Electrode-Type Resistivity Tools in
Invaded Thin Beds},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {32},
Number = {3},
Pages = {494-498},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1109/36.297967},
Abstract = {In this paper, we formulate and implement a numerical
mode-matching (NMM) method to model electrode-type
resistivity tools in invaded thin beds. We derive the
low-frequency approximation of the Maxwell's equations to
obtain the partial differential equation for the potential
field. The new NMM program is validated by comparing the
numerical results with those obtained from other dc
programs. It is found that this new program is much faster
than the program using the finite-element method (FEM), and
hence is useful for routine interpretation of resistivity
logs and for inversion. © 1994 IEEE.},
Doi = {10.1109/36.297967},
Key = {fds283580}
}
@article{fds283581,
Author = {Liu, QH},
Title = {Nonlinear Inversion of Electrode-Type Resistivity
Measurements},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {32},
Number = {3},
Pages = {499-507},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1109/36.297968},
Abstract = {This paper deals with the inversion of low-frequency
electrode-type resistivity measurements for the conductivity
distribution in a two-dimensional axisymmetric medium. It is
well known that the inversion of such transverse magnetic
(TM) measurements is much more nonlinear than that of TE
(transverse electric) measurements. The distorted Born
iterative method (DBIM) is applied to solve the nonlinear
inverse problem. In each iteration of the DBIM, an efficient
numerical mode-matching (NMM) method is used as a forward
solver. In addition to its efficiency in solving for the
predicted data, the NMM method gives a semianalytic
expression for the partial derivatives of the Green's
function required in the inversion. Several numerical
results are presented to demonstrate the applications of the
DBIM, and to address several practical issues related to the
performance of the nonlinear inversion scheme. Because of
the fast forward modeling and semianalytic Green's function
available due to the NMM method, the inversion is fast and
is practical for the interpretation of measurement data. ©
1994 IEEE.},
Doi = {10.1109/36.297968},
Key = {fds283581}
}
@article{fds283582,
Author = {Liu, Q and Chew, WC},
Title = {Applications of the conjugate gradient fast Fourier Hankel
transfer method with an improved fast Hankel transform
algorithm},
Journal = {Radio Science},
Volume = {29},
Number = {4},
Pages = {1009-1022},
Publisher = {American Geophysical Union (AGU)},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1029/93RS03592},
Abstract = {The conjugate gradient fast Fourier‐Hankel transforms
(CG‐FFHT) method was recently proposed to solve the
problems of electromagnetic wave propagation and scattering
in axisymmetric inhomogeneous media. This new technique uses
the CG method together with the FFHT to solve the wave
equation iteratively. Each iteration of the CG method
requires O(N log2 N) complex multiplications (N is the
number of unknowns). For the application of low‐frequency
induction logging, the number of iterations is very small
(less than eight). Furthermore, the CG‐FFHT method only
requires the storage of several vectors of dimension N. In
this paper we present an improved fast Hankel transform
(FHT) algorithm as well as some applications of the
CG‐FFHT method. It is shown that the improved FHT
algorithm results in better accuracy and is more efficient
than the other FHT algorithms. Moreover, with this FHT
algorithm there is no need to pad the function to be
transformed with zeros. Several numerical examples will be
shown to illustrate the use of the improved FHT algorithm as
well as the applications of the CG‐FFHT method. Copyright
1994 by the American Geophysical Union.},
Doi = {10.1029/93RS03592},
Key = {fds283582}
}
@article{fds283583,
Author = {Knizhnerman, L and Druskin, V and Liu, Q and Kuchuk,
FJ},
Title = {Spectral Lanczos decomposition method for solving
single‐phase fluid flow porous media},
Journal = {Numerical Methods for Partial Differential
Equations},
Volume = {10},
Number = {5},
Pages = {569-580},
Publisher = {WILEY},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1002/num.1690100504},
Abstract = {A three‐dimensional well model (r − θ − z) for the
simulation of single‐phase fluid flow in porous media is
developed. Rather than directly solving the 3‐D parabolic
PDE (partial differential equation) for fluid flow, the PDE
is transformed to a linear operator problem that is defined
as u = f(A)σ, where A is a real symmetric square matrix and
σ is a vector. The linear operator problem is solved by
using the spectral Lanczos decomposition method. This
formulation gives continuous solutions in time. A 7‐point
finite difference scheme is used for the spatial
discretization. The model is useful for well testing
problems as well as for the simulation of the wireline
formation tester tool behavior in heterogeneous reservoirs.
The linear operator formulation also permits us to obtain
solutions in the Laplace domain, where the wellbore storage
and skin can be incorporated analytically. The
infinite‐conductivity (uniform pressure) wellbore
condition is preserved when mixed boundary conditions, such
as partial penetration, occur. The numerical solutions are
compared with the analytical solutions for fully and
partially penetrated wells in a homogeneous reservoir. ©
1994 John Wiley & Sons, Inc. Copyright © 1994 Wiley
Periodicals, Inc.},
Doi = {10.1002/num.1690100504},
Key = {fds283583}
}
@article{4761940,
Author = {Chew, WC and Liu, QH},
Title = {Inversion of Induction Tool Measurements Using the Distorted
Born Iterative Method and CG-FFHT},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {32},
Number = {4},
Pages = {878-884},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1109/36.298015},
Keywords = {geophysical prospecting;geophysical techniques;Green's
function methods;inverse problems;terrestrial
electricity;transforms;},
Abstract = {The inversion of induction tool measurements using the
distorted Born iterative method (DBIM) and the conjugate
gradient-fast Fourier-Hankel transform (CG-FFHT) is
described. The inverse problem is formulated in terms of an
integral equation of scattering where the unknown to be
sought is the conductivity in the rock formation, when tHe
measurements along a boreHole axis are performed. The
nonlinear problem is linearized at each stage using the
distorted Born approximation. The inhomogeneous medium
Green's function in the distorted Born approximation is
found by solving a volume integral equation using the
CG-FFBT method, which allows a rapid solution to a large
problem with reduced computational complexity and memory
requirement. In this manner, the inverse problem is solved
with a computational complexity proportional to NtlN log N
where Ntl is the number of transmitter locations used in the
data collection and N is the total number of pixels used to
model the unknown formation. The memory requirement is of
order NNtl. © 1994 IEEE},
Doi = {10.1109/36.298015},
Key = {4761940}
}
@article{fds341227,
Author = {Liu, Q},
Title = {Transient electromagnetic modeling with the generalized
K‐space (GkS) method},
Journal = {Microwave and Optical Technology Letters},
Volume = {7},
Number = {18},
Pages = {842-848},
Year = {1994},
Month = {January},
url = {http://dx.doi.org/10.1002/mop.4650071809},
Abstract = {A centralized k‐space (GkS) method is developed for
transient electromagnetic modeling. This method consists of
the solution of two equations: (1) the scattering equation
in the spectral‐time < k − t) domain, and (2) the
constitutive equation in the spatial‐time (r − t)
domain. Both are derived as local algebraic equations, and
therefore can be solved with O(N) operations. The connection
between the r − t domain and k − t domain is obtained by
the spatial FFT algorithm. Therefore, in each time step, the
number of complex multiply‐add operations is O(N Iog2 N),
and the storage requirement is O(N). Because it treats the
spatial derivatives by Fourier transform, the k‐space
method, compared to the finite‐difference method, provides
a high‐order accuracy for the same discretization. It is
shown that with the same accuracy requirement, the GkS
method requires much fewer unknowns than the conventional
finite‐difference method. © 1994 John Wiley & Sons, Inc.
Copyright © 1994 Wiley Periodicals, Inc., A Wiley
Company},
Doi = {10.1002/mop.4650071809},
Key = {fds341227}
}
@article{fds283787,
Author = {Liu, QH},
Title = {DBIM for the inversion of two-dimensional axisymmetric
inhomogeneous media},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {504-507},
Year = {1993},
Month = {December},
Abstract = {In this work, we apply the distorted Born iterative method
(DBIM) to invert TE measurements for the complex
permittivity distribution in an axisymmetric inhomogeneous
medium. The sensor used to probe this medium consists of
several coaxial loop transmitting and receiving antennas,
and the measurements are made at the rotation
axis.},
Key = {fds283787}
}
@article{fds283788,
Author = {Liu, QH and Anderson, B and Chew, WC},
Title = {Modeling low-frequency electrode-type resistivity tools in
2-D formations},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {1},
Pages = {273-275},
Year = {1993},
Month = {December},
Abstract = {In this work, we derive the low-frequency approximation of
the Maxwell's equations to obtain the partial differential
equation for the potential field. We then formulate and
implement a numerical mode-matching (NMM) method to solve
this two-dimensional potential field in order to model
electrode-type resistivity tools in invaded thin beds. The
new NMM program is validated by comparing the numerical
results with those obtained from other DC programs. It is
found that this new program is much faster than the program
using the finite-element method (FEM), and hence is useful
for routine interpretation of resistivity logs. We
illustrate one application of the NMM program with an
inversion of multiple field logs.},
Key = {fds283788}
}
@article{fds283490,
Author = {Qing-Huo Liu},
Title = {Electromagnetic field generated by an off-axis source in a
cylindrically layered medium with an arbitrary number of
horizontal discontinuities},
Journal = {Geophysics},
Volume = {58},
Number = {5},
Pages = {616-625},
Publisher = {Society of Exploration Geophysicists},
Year = {1993},
Month = {January},
ISSN = {0016-8033},
url = {http://dx.doi.org/10.1190/1.1443445},
Abstract = {Investigates the propagation of electromagnetic waves in a
cylindrically layered medium with an arbitrary number of
horizontal discontinuities. A coupling exists between the
transverse electric and transverse magnetic components of
the field even in the absence of the horizontal
discontinuities, which makes is difficult to solve for the
field. An efficient numerical mode-matching (NMM) algorithm
is applied to tacke this 2.5-D problem. For several special
geometries, the numerical results from this NMM algorithm is
compared with analytical solutions as well as the earlier
numerical results for axisymmetric cases. -from
Author},
Doi = {10.1190/1.1443445},
Key = {fds283490}
}
@article{fds283790,
Author = {Liu, Q and Chew, WC},
Title = {A CG‐FFHT method for the scattering solution of
axisymmetric inhomogeneous media},
Journal = {Microwave and Optical Technology Letters},
Volume = {6},
Number = {2},
Pages = {101-104},
Publisher = {WILEY},
Year = {1993},
Month = {January},
url = {http://dx.doi.org/10.1002/mop.4650060205},
Abstract = {We propose a new technique to solve the integral equation
for wave scattering by an axisymmetric inhomogeneity using
the conjugate gradient (CG) method together with the fast
Fourier‐Hankel transforms (FFHT). The method uses fast
Hankel transform (FHT) and fast Fourier transform (FFT)
requiring only O(N log N) floatingpoint operations per
iteration and O(N) storage. © 1993 John Wiley & sons, Inc.
Copyright © 1993 Wiley Periodicals, Inc., A Wiley
Company},
Doi = {10.1002/mop.4650060205},
Key = {fds283790}
}
@article{4505447,
Author = {Liu, QH},
Title = {Reconstruction of Two-Dimensional Axisymmetric Inhomogeneous
Media},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {31},
Number = {3},
Pages = {587-594},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1993},
Month = {January},
url = {http://dx.doi.org/10.1109/36.225526},
Keywords = {geophysical techniques;inverse problems;permittivity;terrestrial
electricity;},
Abstract = {In this paper, we use transverse electric (TE) measurements
on the symmetry axis of an axisymmetric inhomogeneous medium
to reconstruct its two-dimensional complex permittivity
distribution. The distorted Born iterative method (DBIM) is
applied to solve the nonlinear inversion problem, and the
numerical mode-matching (NMM) method is used to solve the
forward problem in each iteration. It is shown through
numerical examples that good imaging results can be obtained
by using very simple measurements on the axis of symmetry.
© 1993 IEEE},
Doi = {10.1109/36.225526},
Key = {4505447}
}
@article{fds283786,
Author = {Nie Zai-Ping, and Chew, WC and Liu, QH},
Title = {Electromagnetic scattering from two-dimension-layered media
with axial symmetry},
Journal = {Acta Geophysica Sinica},
Volume = {35},
Number = {4},
Pages = {479-489},
Year = {1992},
Month = {January},
Abstract = {The analysis of electromagnetic propagation and scattering
from axially symetrical, two dimension-layered media with
arbitrary N planar layers in a vertical direction and
cylindrical layers in a radial direction has been made. The
numerical mode matching theory is used to simplify
computation. In this method the discrete numerical
eigenmodes are used in a radial direction and the mode
matching method is used in a vertical direction to derive
the recurrent expressions of the field. This half-analytical
and half-numerical method avoids a large amount of
computation of two dimensions as the infinite element
method. The subsurface electrical parameter profile can be
rebuilt by using the numerical results of the field. This
method can be used as a computer aid explanation tool for
induced logging and deep propagation logging. -from English
summary},
Key = {fds283786}
}
@article{fds283789,
Author = {Liu, Q and Chew, WC},
Title = {Diffraction of nonaxisymmetric waves in cylindrically
layered media by horizontal discontinuities},
Journal = {Radio Science},
Volume = {27},
Number = {5},
Pages = {569-581},
Publisher = {American Geophysical Union (AGU)},
Year = {1992},
Month = {January},
url = {http://dx.doi.org/10.1029/92RS00910},
Abstract = {In this paper a numerically efficient algorithm is developed
for solving the problem of nonaxisymmetric wave propagation
in cylindrically layered media with horizontal
discontinuities. For an off‐axis source in cylindrically
layered media, because the nonaxisymmetry of the waves gives
rise to the vectorial coupling between TE and TM waves, the
modeling of the wave propagation becomes much more difficult
than for a centered (axisymmetric) source. However, the
numerical mode‐matching method proposed here calculates
very efficiently the electromagnetic fields in cylindrically
layered media with horizontal discontinuities. Several
numerical examples are given to verify the numerical method
and to illustrate the applications of this method in the
calculation of the field generated by a magnetic dipole
source. Copyright 1992 by the American Geophysical
Union.},
Doi = {10.1029/92RS00910},
Key = {fds283789}
}
@article{4166027,
Author = {Chew, WC and Wang, YM and Otto, G and Wagner, RL and Gürel, L and Liu,
QH},
Title = {A Generalized Recursive Algorithm for Wave-Scattering
Solutions in Two Dimensions},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {40},
Number = {4},
Pages = {716-723},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1992},
Month = {January},
url = {http://dx.doi.org/10.1109/22.127521},
Keywords = {computational complexity;electromagnetic wave
scattering;matrix algebra;},
Abstract = {A generalized recursive algorithm valid for both the
E<inf>z</inf>and H<inf>z</inf>wave scattering of densely
packed scatterers in two dimensions is derived. This is
unlike previously derived recursive algorithms which have
been found to be valid only for E<inf>z</inf>polarized waves
[l]-[7]. In this generalized recursive algorithm, a
scatterer is first divided into N subscatterers. The
n-subscatterer solution is then used to solve the (n +
n')-subscatterer solution. The computational complexity of
such an algorithm is found to be of O(N<sup>2</sup>) in two
dimensions, and mean-while, providing a solution valid for
all angles of incidence. This is better than the method of
moments with Gaussian elimination which has an
O(N<sup>3</sup>) complexity. © 1992 IEEE},
Doi = {10.1109/22.127521},
Key = {4166027}
}
@article{fds322899,
Author = {Liu, QH},
Title = {Modeling of A 2.5-dimensional problem in electromagnetic
well logging},
Journal = {International Geoscience and Remote Sensing Symposium
(Igarss)},
Volume = {1},
Pages = {215-217},
Publisher = {IEEE},
Year = {1992},
Month = {January},
ISBN = {0780301382},
url = {http://dx.doi.org/10.1109/IGARSS.1992.576671},
Abstract = {In this paper, the numerical mode matching (NMM) method is
applied to solve a cylindrical 2;-dimensional (2 1/2-D)
problem encountered in many electromagnetic well logging
applications. We consider the radiation of an off-axis
source in an axisymmetric inhomogeneous medium consisting of
an arbitrary number of layers in both the radial and axial
directions. The method of Fourier series is first used to
transform the 23-D problem into a series of two-dimensional
(2-D) problems, which are in turn solved by the NMM method.
Like the NMM method used for the 2-D scalar problem, the NMM
method used here converts a 2-D vectorial problem into
several one-dimensional ones. Therefore, we expect a great
saving in the computer memory and the computation time with
NMM, particularly when compared with the more conventional
2-D finite element method (FEM). Several numerical examples
are shown to illustrate the efficiency and the application
of the NMM method.},
Doi = {10.1109/IGARSS.1992.576671},
Key = {fds322899}
}
@article{3902059,
Author = {Chew, WC and Nie, Z and Liu, QH and Anderson, B},
Title = {An Efficient Solution for the Response of Electrical Well
Logging Tools in a Complex Environment},
Journal = {Ieee Transactions on Geoscience and Remote
Sensing},
Volume = {29},
Number = {2},
Pages = {308-313},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1991},
Month = {January},
url = {http://dx.doi.org/10.1109/36.73673},
Keywords = {geophysical prospecting;geophysical techniques;terrestrial
electricity;},
Abstract = {An efficient method for computing the response of some
electrical logging tools in a complex environment is
presented. This complex environment consists of multiple
geological beds with a borehole and invaded zones. The
method uses local reflection and transmission operators of a
single-bed boundary and a general recursive algorithm to
derive generalized reflection and transmission operators.
Using this method, the computation time scales linearly as
N, where N is the number of beds in the environment. Hence
the method is much more efficient than the finite-element
method for solving the same problem. Furthermore, the
solution is presented in a symmetric form so that
reciprocity can be readily verified. © 1991
IEEE},
Doi = {10.1109/36.73673},
Key = {3902059}
}
@article{3911581,
Author = {Liu, QH and Chew, WC},
Title = {Analysis of Discontinuities in Planar Dielectric Waveguides:
An Eigenmode Propagation Method},
Journal = {Ieee Transactions on Microwave Theory and
Techniques},
Volume = {39},
Number = {3},
Pages = {422-430},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1991},
Month = {January},
url = {http://dx.doi.org/10.1109/22.75283},
Keywords = {dielectric waveguides;eigenvalues and eigenfunctions;S-parameters;waveguide
theory;},
Abstract = {In this paper the eigenmode propagation method is proposed
to analyze the discontinuity problems in planar dielectric
waveguides. This new recursive algorithm is based on the
numerical mode matching method, but it uses less computation
time and computer memory, which makes the analysis of
multiregion, vertically stratified media much more
effective. With this algorithm, the required computer memory
is independent of the number of regions in the problem, and
the computation time is linearly proportional to the number
of regions. Therefore, it is particularly suitable for the
analysis of planar waveguide discontinuities and waveguide
bends. Using this method, we can analyze larger problems
which are impractical with the finite element method. From
the numerical examples given in the paper, it is
demonstrated that the computation time is linearly
proportional to the number of discontinuities, while the
computer memory is almost a constant independent of the
number of discontinuities, N. © 1991 IEEE},
Doi = {10.1109/22.75283},
Key = {3911581}
}
@article{91080262081,
Author = {Moghaddam, M and Chew, WC and Anderson, B and Yannakakis, E and Liu,
QH},
Title = {Computation of transient electromagnetic waves in
inhomogeneous media},
Journal = {Radio Science},
Volume = {26},
Number = {1},
Pages = {265-273},
Publisher = {American Geophysical Union (AGU)},
Address = {Stockholm, Swed},
Year = {1991},
Month = {January},
url = {http://dx.doi.org/10.1029/90RS00924},
Keywords = {Mathematical Transformations - Fourier Transforms;Mathematical
Techniques - Numerical Methods;},
Abstract = {A brief summary of the methods of solving transient
electromagnetic wave problems in inhomogeneous media will be
given. The two distinct general techniques, which are the
inverse Fourier transformation of time‐harmonic solutions
and the direct time‐domain formulation, will be
illustrated by way of two examples. In the first example, an
efficient numerical mode‐matching method to obtain the
response of an electromagnetic source in a two‐dimensional
cylindrical inhomogeneity is described. Using this method,
the solution is first obtained in the frequency domain. The
time‐domain solution is then found by inverse Fourier
transforming the frequency‐domain solution. In the second
method, a finite‐difference scheme is used to find the
transient response of a point source in a two‐dimensional
inhomogeneity. Two different methods are proposed to treat
the source region singularity. Transmitting boundary
conditions are applied on the walls of the finite difference
grid so that a finite‐sized box can be used to model an
infinite region. Copyright 1991 by the American Geophysical
Union.},
Doi = {10.1029/90RS00924},
Key = {91080262081}
}
@article{3893533,
Author = {Chew, WC and Nie, Z and Liu, QH and Lo, YT},
Title = {Analysis of a probe-fed microstrip disk antenna},
Journal = {Iee Proceedings H: Microwaves, Antennas and
Propagation},
Volume = {138},
Number = {2},
Pages = {185-191},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {1991},
Month = {January},
url = {http://dx.doi.org/10.1049/ip-h-2.1991.0030},
Keywords = {antenna theory;electric impedance;microstrip
antennas;variational techniques;},
Abstract = {The input impedance of a probe-fed, annular-ring-loaded,
circular-disk microstrip antenna is analysed using three
methods of increasing complexity and sophistication. The
first method uses a new variational formula which is more
suitable for antennas driven by a voltage gap. The second
method uses a mode-matching method where the field inside
the coaxial line is expanded in terms of waveguide modes.
The third method uses the mode-matching method with a
diaphragm at the coaxial aperture. The mode-matching methods
are identical to the variational formula under the
single-mode approximation. However, when a diaphragm is
present, the single-mode approximation is insufficient,
implying that the variational formula is inaccurate when a
diaphragm exists. The theory is used to study the effect of
the gap capacitance at the coaxial aperture on the input
impedance of the microstrip antenna. It is found that this
gap capacitance is important when the dielectric substrate
is thick.},
Doi = {10.1049/ip-h-2.1991.0030},
Key = {3893533}
}
@article{91050206180,
Author = {Chew, W.C. and Nie, Z. and Liu, Q.H. and Lo,
Y.T.},
Title = {Analysis of a probe-fed microstrip disk antenna},
Journal = {IEE Proceedings, Part H: Microwaves, Antennas and
Propagation},
Volume = {138},
Number = {2},
Pages = {185 - 191},
Year = {1991},
Keywords = {Probes;Dielectric Materials;Microstrip Devices;Disks;Mathematical
Techniques--Variational Techniques;},
Abstract = {The input impedance of a probe-fed, annular-ring-loaded,
circular-disk microstrip antenna is analysed using three
methods of increasing complexity and sophistication. The
first method uses a new variational formula which is more
suitable for antennas driven by a voltage gap. The second
method uses a mode-matching method where the field inside
the coaxial line is expanded in terms of waveguide modes.
The third method uses the mode-matching method with a
diaphragm at the coaxial aperture. The mode-matching methods
are identical to the variational formula under the
single-mode approximation. However, when a diaphragm is
present, the single-mode approximation is insufficient,
implying that the variational formula is inaccurate when a
diaphragm exists. The theory is used to study the effect of
the gap capacitance at the coaxial aperture on the input
impedance of the microstrip antenna. It is found that this
gap capacitance is important when the dielectric substrate
is thick.},
Key = {91050206180}
}
@article{3932736,
Author = {Liu, QH and Chew, WC},
Title = {Analysis of complex rectangular dielectric
waveguides},
Journal = {J. Electromagn. Waves Appl. (Netherlands)},
Volume = {5},
Number = {3},
Pages = {253-266},
Year = {1991},
url = {http://dx.doi.org/10.1163/156939391X00031},
Keywords = {dielectric waveguides;finite element analysis;numerical
methods;rectangular waveguides;waveguide
theory;},
Abstract = {A rigorous method for the analysis of the propagation
characteristics of various rectangular waveguides is
proposed based on the recent development of the numerical
mode matching method for multi-region, vertically stratified
media. The method uses the propagation properties of the
waves on the cross-section of the waveguides to convert the
two-dimensional problem into a few one-dimensional problems.
These one-dimensional problems are then solved with the
one-dimensional finite element method. This analysis method
has been implemented numerically for analyzing arbitrary
structures of rectangular dielectric waveguides. The
comparison of the results with those available in literature
are favorable. With the numerical results for various
waveguide structures, the method is demonstrated to be
efficient and capable of solving very complex structures
such as coupled rib waveguides and coupled channel
waveguides},
Doi = {10.1163/156939391X00031},
Key = {3932736}
}
@article{fds283578,
Author = {Chew, WC and Nie, Z and Liu, QH and Anderson, B},
Title = {Modeling of well logging tools in a multibed environment
with invasions},
Journal = {Digest International Geoscience and Remote Sensing Symposium
(Igarss)},
Pages = {19-22},
Year = {1990},
Month = {December},
Abstract = {A numerical mode matching method is presented for the
analysis of wave propagation in multibed environments with
invasions. An invaded multibed environment is modeled as a
multiregion, cylindrically stratified medium. The scattering
of electromagnetic waves by this inhomogeneous medium is
analyzed by mode matching on the interfaces of the bed
boundaries. The eigenmodes of each region of cylindrically
stratified medium are found by using one-dimensional finite
element method, providing the flexibility of the method,
while the mode matching on the interfaces of the bed
boundaries is performed by introducing the reflection and
transmission operators, and generalized reflection
operators. Since the unknowns in this problem are only in
one dimension (i.e., on the interfaces of the bed
boundaries), this method is shown very efficient compared to
the conventional two-dimensional finite-element method. Some
numerical results are presented.},
Key = {fds283578}
}
@article{3966253,
Author = {Chew, WC and Nie, Z and Liu, QH and Anderson, B},
Title = {A full wave analysis of wave propagation in multiregion,
cylindrically stratified media},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {2},
Pages = {602-605},
Address = {Dallas, TX, USA},
Year = {1990},
Month = {December},
url = {http://dx.doi.org/10.1109/APS.1990.115182},
Keywords = {electromagnetic wave propagation;electromagnetic wave
scattering;numerical methods;physics computing;},
Abstract = {The wave scattering problem for a general multiregion,
cylindrically stratified medium is formulated using the
numerical mode matching method. The excitation of the wave
is assumed to be axially symmetric and, hence, the field in
the cylindrical structure will also have axial symmetry. A
computer program have been developed for a general
multiregion, vertically stratified medium, with arbitrarily
many layers in both the vertical and the horizontal
directions. Some numerical results are presented to
demonstrate the use of this method. The efficiency of this
method is about 100 times higher than that of the
finite-element method. The computation time is linear in N,
where N is the number of regions.},
Key = {3966253}
}
@article{91070243495,
Author = {Chew, WC and Nie, Z and Liu, QH and Lo, YT},
Title = {Some methods of analysis of a probe-fed microstrip disk
antenna},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {346-349},
Address = {Dallas, TX, USA},
Year = {1990},
Month = {January},
url = {http://dx.doi.org/10.1109/APS.1990.115118},
Keywords = {Probes;Disks;Diaphragms;Electric Measurements--Impedance;Microstrip
Devices;},
Abstract = {The authors present three methods (with increasing
complexity) of incorporating the gap capacitance of the
probe basis into the input impedance calculation of a
probe-fed antenna. They are the variational formula, the
mode-matching method, and the mode-matching method with a
diaphragm. It is noted that in the previous approach the gap
capacitance of the probe base that shunts the input
impedance of the microstrip antenna is not included in the
input impedance. Under the single-mode approximation, the
mode-matching methods are identical to the variational
formula. However, when a diaphragm is present, the
single-mode approximation is insufficient. Therefore, the
variational formula is inaccurate when a diaphragm exists.
The theory shows that the effect of the gap capacitance at
the coaxial aperture on the input impedance of the
microstrip antenna is important when the dielectric
substrate is thick. The theories agree well with experiment
data with no fudge factors.},
Doi = {10.1109/aps.1990.115118},
Key = {91070243495}
}
@article{3710775,
Author = {Liu, QH and Chew, WC},
Title = {Surface Integral Equation Method for the Analysis of an
Obliquely Stratified Half-Space},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {38},
Number = {5},
Pages = {653-663},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1990},
Month = {January},
url = {http://dx.doi.org/10.1109/8.53493},
Keywords = {electromagnetic wave propagation;finite element
analysis;Green's function methods;integral
equations;},
Abstract = {The radiation of a source in the presence of an obliquely
stratified halfspace is studied using the surface integral
equation method (SIEM). A generalized extinction theorem for
the obliquely stratified halfspace problem is derived, which
gives eight surface integral equations for the fields. The
Green's functions for the stratified media are found by a
semi-analytical method. Using these surface integral
equations, the rather complicated two-dimensional problem
can be solved by the one-dimensional finite element method
(FEM), which saves computer memory and computation time
compared to that for the conventional two-dimensional finite
element method. For some special cases, the results obtained
by this method are compared with those obtained by the
numerical mode matching method and the Fourier integral
technique. Excellent agreement has been observed between
them. This method is general for any obliquely stratified
halfspace with arbitrarily many layers in each region. ©
1990 IEEE},
Doi = {10.1109/8.53493},
Key = {3710775}
}
@article{3689341,
Author = {Liu, QH and Chew, WC},
Title = {Numerical Mode-Matching Method for the Multiregion
Vertically Stratified Media},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {38},
Number = {4},
Pages = {498-506},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1990},
Month = {January},
url = {http://dx.doi.org/10.1109/8.52268},
Keywords = {electromagnetic wave propagation;finite element
analysis;},
Abstract = {The response of a source in the presence of the N-region,
vertically stratified media is an unsolved problem. The
finite element method is not appropriate for this problem
because of the infinite size of the scatterer. In this
paper, the numerical mode-matching method is used to solve
this problem. By treating the fields propagating in the
direction parallel to the subboundaries of the stratified
media in terms of the propagators, and by introducing the
concept of reflection operators, transmission operators, and
generalized reflection operators, we reduce this
twodimensional problem into several one-dimensional problems
which are solved by the one-dimensional finite element
method (FEM). The one-dimensional finite element method
saves computer storage and computation time compared to the
twodimensional finite element method. A formulation valid
for a general N-region vertically stratified medium is
derived. When there are only three regions, the comparison
of the results with those in the literature is very good.
Some typical numerical results for N > 3 are also shown.
This solution can be applied to many areas including
geophysical prospecting, integrated optics, nondestructive
testing, and biological sensing. © 1990
IEEE},
Doi = {10.1109/8.52268},
Key = {3689341}
}
@article{fds283574,
Author = {Liu, Q and Chew, WC},
Title = {Simple formulas for the resonant frequencies of microstrip
patches},
Journal = {Ap S International Symposium (Digest) (Ieee Antennas and
Propagation Society)},
Volume = {1},
Pages = {14-17},
Year = {1988},
Month = {December},
Abstract = {A study is made of the resonant frequencies of rectangular
and circular microstrip patches to develop design formulas
for the resonant frequencies. The resonant frequency problem
of rectangular microstrip patches is formulated using vector
Hankel transforms. Both formulations result in integral
equations for which Galerkin's method is used to ascertain
the resonant frequencies. The results agree with experiments
and asymptotically agree with the perturbation approach.
Based on these solutions, the design formulas for the
microstrip patches are developed using least-square
fits.},
Key = {fds283574}
}
@article{fds283575,
Author = {Chew, WC and Liu, Q},
Title = {Resonance Frequency of a Rectangular Microstrip
Patch},
Journal = {Ieee Transactions on Antennas and Propagation},
Volume = {36},
Number = {8},
Pages = {1045-1056},
Publisher = {Institute of Electrical and Electronics Engineers
(IEEE)},
Year = {1988},
Month = {January},
url = {http://dx.doi.org/10.1109/8.7216},
Abstract = {The microstrip patch resonant frequency problem is
formulated in terms of an integral equation using vector
Fourier transforms. In the spectral space represented by the
vector Fourier transforms, the Green's function is diagonal.
Using Galerkin's method in solving the integral equation,
the resonant frequency of the microstrip patch is studied
with both Chebyshev polynomials and sinusoidal functions as
basis functions. In the case of the Chebyshev polynomials,
the edge singularity is included, but it is not important
for convergence. Furthermore, the resonant frequency of the
microstrip patch is ascertained with a perturbation
calculation. The results for Galerkin's method and
experiments are in good agreement. The perturbation
calculation agrees asymptotically with Galerkin's method.
With the aim of developing a computer-aided design formula,
the solutions obtained via Galerkin's method are
interpolated with a three-variable polynomial. The
polynomial formula can reproduce the solution of the
integral equation using Galerkin's method rapidly. © 1988
IEEE},
Doi = {10.1109/8.7216},
Key = {fds283575}
}
@article{fds283576,
Author = {Liu, Q and Chew, WC},
Title = {Curve-fitting formulas for fast determination of accurate
resonant frequency of circular microstrip
patches},
Journal = {Iee Proceedings H: Microwaves, Antennas and
Propagation},
Volume = {135},
Number = {5},
Pages = {289-292},
Publisher = {Institution of Engineering and Technology
(IET)},
Year = {1988},
Month = {January},
url = {http://dx.doi.org/10.1049/ip-h-2.1988.0060},
Abstract = {A further study is made of the resonant frequency of
circular microstrip patches. Based on earlier work, the
resonant frequency problem is formulated in terms of an
integral equation. Galerkin's method is used to calculate
the resonant frequencies of nonaxial symmetric modes in
different circular microstrip patches. Using the database
built by Galerkin's method, a curve-fitting formula is
developed to reproduce the accurate resonant frequency
rapidly. The accuracy of this formula is within 1.0%. This
formula is useful for the computer-aided design of
microstrip antennas and microwave integrated
circuits.},
Doi = {10.1049/ip-h-2.1988.0060},
Key = {fds283576}
}
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