TY - JOUR
T1 - New approximate formulations for EM scattering by dielectric objects
AU - Cui, Tie Jun
AU - Chew, Weng Cho
AU - Hong, Wei
N1 - Funding Information:
Manuscript received February 7, 2003; revised April 12, 2003. This work was supported in part by the National Science Foundation of China for Distinguished Young Scholars under Grant 60225001, by the Chinese National High Technology Research Plan (863 Plan) under Grant 2002AA123031, by the U.S. Department of Energy under Grant DOE DEFG07-97ER 14835, and in part by the U.S. National Science Foundation under Grant NSF ECS 99-06651.
PY - 2004/3
Y1 - 2004/3
N2 - The extended Born approximation (ExBorn) has been shown an efficient formulation in the electromagnetic (EM) scattering by dielectric objects in both free-space and air-earth half-space problems. In most cases, ExBorn is much more accurate than the conventional Born approximation at low frequencies. When the frequency is high or the contrast of dielectric objects is large, however, the ExBorn approximation becomes inaccurate. In this paper, new approximations are proposed for the EM scattering by dielectric objects buried in a lossy earth, which are also suitable for the case of free space. It has been shown that the zeroth-order form of new approximations is completely equivalent to ExBorn. Hence, high-order approximations can be regarded as high-order ExBorn. Closed-form formulations are derived for the new approximations. Using the fast Fourier transform (FFT), these formulations can be implemented efficiently at a cost of CN log N, where N is the number of unknowns and C is a small number. Numerical simulations show that high-order ExBorn approximations are much more accurate than the ExBorn approximation.
AB - The extended Born approximation (ExBorn) has been shown an efficient formulation in the electromagnetic (EM) scattering by dielectric objects in both free-space and air-earth half-space problems. In most cases, ExBorn is much more accurate than the conventional Born approximation at low frequencies. When the frequency is high or the contrast of dielectric objects is large, however, the ExBorn approximation becomes inaccurate. In this paper, new approximations are proposed for the EM scattering by dielectric objects buried in a lossy earth, which are also suitable for the case of free space. It has been shown that the zeroth-order form of new approximations is completely equivalent to ExBorn. Hence, high-order approximations can be regarded as high-order ExBorn. Closed-form formulations are derived for the new approximations. Using the fast Fourier transform (FFT), these formulations can be implemented efficiently at a cost of CN log N, where N is the number of unknowns and C is a small number. Numerical simulations show that high-order ExBorn approximations are much more accurate than the ExBorn approximation.
KW - Born approximation
KW - Buried dielectric objects
KW - Conjugate-gradient fast Fourier transform (CG-FFT) algorithm
KW - Extended Born (ExBorn) approximation
KW - High-order approximations
KW - Low-frequency detection
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U2 - 10.1109/TAP.2004.825159
DO - 10.1109/TAP.2004.825159
M3 - Article
AN - SCOPUS:2442534899
SN - 0018-926X
VL - 52
SP - 684
EP - 692
JO - IEEE Transactions on Antennas and Propagation
JF - IEEE Transactions on Antennas and Propagation
IS - 3
ER -