分层媒质中浅二维目标的探测

Detection of Shallow Two-Dimensional objects in Layered Media

本文探讨利用时域散射场信息探测分层媒质中法二维目标、分层媒质中目标的探测具有明显的应用价值．但相对自由空间而言，这种探测要困难得多。本文给出一种基于体等效原理的探测分层媒质中钱二维目标的方法。这是一种选代方法．从一阶玻恩近似开始迭代．每次迭代过程中正问题和逆问题各计算一欢，正问题采用FDTD方法。利用体等效原理，得到反映时域散射场和目标介电常数分布之间关系的体积分方程，经傅立叶变换并离散化后得到反演方程。为了克服问题的病态．采用了伪求逆技术、文中列举了几个具有代表性的例子，最后讨论了有关的几个问题。

The detection of shallow two-dimensional objects in layered media by using timedomain scattering data is considered in this paper. A volume integral equation which relates thescattering fields in time domain with the permittivity of the objects is obtained by volumeequivalence principle. By Fourier transform, the equation is transformed into frequency domainand the inversion equation is obtained after discretization. This is an iterati.e method, In eachiteration, both the forward and the inverse problems are solved once. The forward problem issolved by using Finite-Difference Time-Domain method. The inverse problem is. carried out byusing a pseudoinverse technique. Several examples are given to show the ability of this method toinvert arbitrarily shaped objects.