二维密集导体目标散射的数值模式匹配法  

Numerical mode match method for scattering computation of densely distributed 2D PEC targets

作　　者：叶红霞[1] 金亚秋[1] 

机构地区：[1]复旦大学波散射与遥感信息教育部重点实验室,上海200433

出　　处：《电波科学学报》2010年第2期203-208,共6页Chinese Journal of Radio Science

基　　金：国家自然科学基金资助项目(No.40637033)

摘　　要：用数值模式匹配法(Numerical Mode Match,NMM)求解空间随机分布的二维任意形状导体柱目标的复合散射。每个目标的散射场在各自局部坐标系中用柱面波函数展开,外部空间的散射场由所有目标散射场的叠加共同贡献。在每个导体目标表面选取若干离散点数值匹配边界条件,得到关于展开系数的超定矩阵方程,用奇异值分解(Singular Value Decomposition,SVD)或最小二乘法获得其最佳逼近解。这样,空间的散射场可由级数展开解析计算。数值分析了展开级数的截断问题,与矩量法(Method of Moment,MoM)数值计算的结果比较和误差分析获得不同形状和不同尺寸目标的展开项数,并用多项式拟合了简单的函数式。最后,针对不同形状组合的多导体柱复合散射模型分析其双站散射计算,与MoM方法的结果比较表明:数值模式匹配法能快速准确地分析任意尺寸任意位置任意形状复合目标的散射计算。Numerical mode match method（NMM） for cylindrical wave function expansion is developed for fast computation of electromagnetic scattering from a composite model of 2D conductive targets with random positions,sizes and shapes.Firstly,the scattering field of each target is expanded in the series summation of Hankel functions in its local coordinate.The total scattering field in outside space is contributed by all targets including their interactions,and the field inside each target is zero.Finite sampling points on each target surface are chosen to numerically match boundary conduction equation,to yield a matrix equation of the expansion coefficients.In order to well restrict the boundary conduction on all target surface,the sampling point number should be more than the unknown expansion coefficients,and the matrix equation is overdetermined.The singular value decomposition（SVD） or the least squares method is used to obtain the optimal solution.Then,the scattering field in outside space can be computed as series summation of the cylindrical wave functions.The series truncation and the relation of series number and target size for different shapes are also discussed.Finally,numerical simulation is presented for scattering analysis of multiple scattering of randomly and densely distributed 2D conductive targets,and comparison with the conventional MoM computation for validation of this new method are discussed.

关 键 词：柱面波展开 边界条件 奇异值分解 

分 类 号：TM152[电气工程—电工理论与新技术] TM153