An Electromagnetic Inverse Scattering Technique in Time Domain for Drude Dispersive Media
LIU Guang-dong1, GE Xin-tong2
1. School of Physics and Electronic Engineering, Fuyang Normal College, Fuyang, Anhui 236037, China;
2. School of Mathematics and Statistics, Fuyang Normal College, Fuyang, Anhui 236037, China
Drude empirical models are frequently used for description of dispersion characteristics of many media, such as plasmas, and metals.Reconstructed electrical properties by directly using wide-band measured data in time domain, are better than those by application of any single-frequency technique, in amount of information, and resolution of generated images.One of difficulties in time-domain reconstruction of dispersive characteristics is their frequency correlation.In order to overcome this difficulty, an electromagnetic (EM) inverse scattering technique in time domain is proposed, in which four kinds of frequency-independence parameters from a Drude model are estimated simultaneously.Main segments for the technology are:(1) formulating the inverse scattering problem as a constrained minimization problem with a term of regularization;(2) transforming resulting problem into an unconstrained minimization one;(3) deriving a set of closed gradients of its cost functional;(4) solving iteratively resulting forward and backward sub-problems by a finite-difference time-domain (FDTD) method and any conjugate gradient (CG) algorithm, respectively.In one-dimensional (1-D) and two-dimensional (2-D) numerical examples, necessary measurements are replaced by simulated fields based on the FDTD method, and it is assumed that they are corrupted by an additive white Gaussian noise (AWGN).Numerical results preliminarily confirm performance of the inversion methodology.
刘广东, 葛新同. 时域反演德鲁色散媒质的电磁逆散射技术[J]. 电子学报, 2016, 44(2): 385-391.
LIU Guang-dong, GE Xin-tong. An Electromagnetic Inverse Scattering Technique in Time Domain for Drude Dispersive Media. Chinese Journal of Electronics, 2016, 44(2): 385-391.
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2016, Vol. 44 
