电大三维非均匀介质体散射特性的快速分析

在体积分方程矩量法(VIE-MoM)中,采用多层快速多极子技术(MLFMA)并结合近场预条件技术,快速分析电大尺寸三维非均匀介质目标的电磁散射特性.在实施MLFMA加速技术的基础上,选取系数矩阵中近场耦合元素构造出具有近似对角特征的稀疏化矩阵,对其求逆快速构造预条件因子,用以加快GMRES迭代收敛速度.通过电大尺寸介质平板算例验证了MLFMA计算程序的正确性及其在节省计算时间和内存需求方面的明显效果.对非均匀半球壳介质体和三层非均匀介质平板的RCS进行了计算,采用上述预条件技术,收敛计算效率分别提高了87%和42%.数值结果表明,采用MLFMA结合预条件技术的VIE-MoM,是解决快速分析电大尺寸非均匀介质体散射问题的有效途径.

Fast analysis of RCS of electrically large 3-D inhomogeneous objects

The multilevel fast multiple algorithm(MLFMA) and a near-field precondition technique are implemented in the method of moment(MoM) based on volume integral equation(VIE) to analyze electromagnetic scattering characteristics of electrically large inhomogeneous objects fast and accurately.After adopting the fast technique of MLFMA,a sparse quasi-diagonal matrix is constructed by retaining relatively large elements corresponding to near field coupling,which is then quickly inversed to form a sparse preconditioner that is utilized to accelerate the convergence speed of the general minimum residual(GMRES) algorithm.The computer program of MLFMA is validated and the effect on saving memory size and computation time is demonstrated by the analysis of an electrically large dielectric plate.Then,the radar cross section(RCS)of an inhomogeneous dielectric half spherical shell and that of a three-layered inhomogeneous dielectric plate are calculated.The computation efficiencies of convergence have improved by 87% and 42% respectively by employing the preconditioning technique.Numerical results show that the proposed fast method of VIE-MoM accelerated by MLFMA combined with preconditioning technique is an efficient approach to analyze electromagnetic scattering characteristics of arbitrary shaped inhomogeneous objects.