自由空间中二维电磁目标的时域非线性反演

提出一种基于电磁等效原理的一组积分方程，应用变分方法和傅立叶变换理论，得到了时域散射场与目标电磁参数之间非线性关系的频域表示式，即反演自由空间中二维电磁目标的时域非线性迭代方法的反演方程。列举了一些典型的数值反演实例，对反演性能进行了多方面的考察，指出本法是一种具有良好反演性能的时域非线性反演方法。

Time Domain Nonlinear Inversion of Two-dimensional Electromagnetic Target in Free Space

A nonlinear inversion algorithm for microwave imaging of two-dimensional object in free space using time domain scattering data with or without the effect of random noise was put fowward in this paper. A set of integral equations was obtained based on the equivalence principle in electromagnetics. Then, the nonlinear relation in frequency domain between the time domain scattered field and the object's dielectric parameters, namely, the inversion equation of this method, was derived by taking variation and Fourier transform on the set. Several typical numerical examples were presented to diplay the excellent inversion properties of the method.