Hybrid model of scattering from eccentrically nested dielectric cylinders

This paper presents an analysis of electromagnetic field scattering from a composite consisting of N eccentric dielectric cylinders. The scattering analysis is based on the finite element method (FEM) using triangular elements for inside the composite cylinder and the boundary element method (BEM) for the unbounded region outside the composite cylinder. The fields outside the eccentric dielectric cylinders are represented in terms of the boundary integral equation. The solution of Helmholtz wave equation inside the eccentric dielectric cylinders (inhomogeneous region) is provided using the finite element method. By applying the boundary conditions between free space and the outermost layer of the eccentric dielectric cylinders, the scattering coefficients of the scattered fields are obtained. The method is very efficient since it maintains the sparsity of the resulting matrix equation. The radar cross section (RCS) of the various geometries is presented. The available numerical results in the literature are used to validate the accuracy of this method.