求解分层介质结构空域格林函数的固定实镜像法

Fixed Real Image Method (FRIM) for Green's Function of Multilayer Media

空域格林函数的求解是矩量法分析分层介质结构的主要困难 ,也是关键所在。在离散复镜像技术的基础上 ,注意到逆问题解的不唯一性 ,提出了一种新方法———固定实镜像法 (FRIM ) ,即在用一组空域复镜像 (表示为复指数级数和 )来拟合谱域格林函数时 ,根据经典镜像理论给定镜像的实位置 ,然后用简单的点匹配法来求出相应实镜像的复幅度。该方法避免了复镜像法中用Prony法或广义函数束法 (GPOF)拟合的复杂计算过程 ,提高了计算速度 ,且物理含义也更加明确。文中给出了该方法的基本原理 ,给出一组数值模拟结果 ,与复镜像法吻合得很好 。

The computation of Green's function in spatial domain is the key difficulty in solving multilayer structure. According to the nonuniqueness of inverse problem, a novel method based on discrete complex image method(DCIM)-fixed real image method(FRIM) is put forward.According to this method, we use fixed images at real instead of complex locations to approximate the spectral Green's function, the images real locations are selected according to the classic image theory, and the complex amplitudes can be obtained using simple point match method. This method is simpler and faster than the complex image method for avoiding the fitting procedure of Prony or GPOF. A group of computation results are given and validated by DCIM.