一种随机粗糙海面电磁散射的极化核函数

从磁场的积分方程出发,应用迭代方法推导了二次迭代条件下粗糙海面的近似电磁散射极化核函数,并对其进行了分析.这种函数的表示是在光学近似即KA近似的基础上的一种扩展形式,因而可称为扩展KA近似(EKA).Elfouhaily采用了与Holliday类似的方法分析了双站配置条件下散射的极化核函数,试图保留所有的高次项,但是由于处理的复杂性他只给出了斜率项在散射项中的表示形式,并称之为KA近似的"补充项".本文在此基础上进一步考虑了Elfouhaily近似的形式,给出了表示双站散射极化核函数的完整表达形式,并以此为基础推算了后向散射条件下极化核函数的理论结果,并与Elfouhaily的结果进行了对比,说明了极化核函数完整表达形式的合理性.近似散射极化核函数的分析对于深入理解粗糙表面(特别是海面)电磁散射特性以及散射近似模型的建立等问题的研究具有重要意义.

A formulation of electromagnetic scattering polarization kernel function on random rough sea surfaces

According to magnetic field integration equation, a formulation of approximate scattering polarization kernel function from a second iteration of surface current integral equation is proposed and analyzed for the scattering from rough surfaces. This kernel function is derived by an extension Kirchhoff Approximation model, and hence so-called the Extended Kirchhoff Approximation model (EKA). Elfouhaily had adopted an approach similar to Holliday's to derive the formulation of the scattering field from perfectly conducting surfaces and obtained a result including a polarization kernel vector that depends on the slope term, which was referred as the supplementary field term by Elfouhaily. In this paper, we present a full form of polarization vector kernel function for bistatic scattering from rough surface, according to an approximated model. Then the theoretical results are given by considering the configuration of back-scattering and compared with the Elfouhaily's model. This analysis is important for the comprehension of the polarization kernel vector function for the electromagnetic scattering of rough surface.