Sparse Matrix Canonical Grid Method for Scattering from 3D Random Dielectric Scatterers
SUN Yu fa 1, CHAN Chi hou 2 (1. Department of Electronic Engineering and Information Science, Anhui University, Hefei 230039, China) (2. Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR, China)
The sparse matrix canonical grid method is employed to analyze electromagnetic scattering from three dimensional random dielectric scatterers in this paper. The method of moments was used to solve the volume integral equation for dielectric scatterers. The impedance matrix is decomposed into a sparse matrix, which corresponds to strong near field interactions, and its complementary matrix, which corresponds to weak far field interactions according to the discrete unit of scatterers. During the iterative solution of the matrix equation by the conjugate gradient method, the far interaction portion of the matrix vector multiplication is computed indirectly using fast Fourier transforms. This is achieved by a Taylor series expansion of the Green's function about the grid points of a uniformly spaced canonical grid. The near interaction portion of the matrix vector multiplication is computed directly. The far scattered fields for several examples are calculated. It is shown that the numerical results are in good agreement with the results achieved by the full matrix method of moments, while the memory requirement and operations are considerably reduced.