Scattering from a Thin Resistive Disk: A Guaranteed Fast Convergence Technique

This article is devoted to the analysis of the electromagnetic scattering from a thin resistive disk. The problem is formulated in terms of a singular integral equation in the vector Hankel transform domain for each cylindrical harmonic of the effective electric current density. Two new unknowns are introduced by means of Helmholtz decomposition: the surface curl-free contribution and the surface divergence-free contribution of the general harmonic of the effective electric current density. Galerkin method with a complete set of orthogonal eigenfunctions of the static part of the integral operator reconstructing the edge behavior and the behavior around the disk center of the unknowns is used to discretize the integral equation. The obtained matrix equation is a Fredholm second-kind equation for which the fast convergence is guaranteed. Moreover, the matrix coefficients are accurately and efficiently evaluated by means of a suitable integration procedure in the complex plane. The numerical results and comparisons with the commercial software CST Microwave Studio are provided in order to show the effectiveness of the proposed method.