旋磁各向异性非均匀球体电磁散射特性

Anisotropic Scattering Characteristics of an Inhomogeneous Gyromagnetic Sphere

应用T矩阵方法推导了旋磁各向异性径向非均匀球体散射场的解析解。置于自由空间的球形结构被分为N个区域,每个区域的材料参数为标量电导率和旋磁张量磁导率。根据球矢量波函数理论将入射场,散射场以及球体内部各个区域的电磁场展开为球矢量波函数的线性叠加,最后通过匹配边界条件求得散射系数。雷达散射截面数值结果与有限元方法得到的数值结果有很好的吻合,验证了公式的正确性与有效性。最后给出几个新的算例分析了旋磁非均匀球体的散射特性。

In this paper, we present an analytical T-matrix solution of Mie type for electromagnetic（EM） scattering by a radially multilayered gyromagnetic anisotropic sphere. A sphere located in free space is divided into N regions, each region is characterized by scalar permittivity and gyromagnetic permeability tensor. Based on the vector spherical wave functions（VSWFs） theory, the incident field, scattered field, and the field inside the sphere are expanded as linear combination of VSWFs. The scattering coefficients and unknown expansion coefficients of each layer are calculated by matching the boundary conditions on the discontinuous surfaces. According to the derived formulations, the numerical results of radar cross sections（RCS） given by proposed analytical method is in good agreement with those computed by finite element method（FEM）. Several calculation examples for some specific cases are also presented to investigate the EM scattering characteristic of multilayered gyromagnetic sphere.