Electromagnetic Scattering by a Zero-Thickness PEC Annular Ring: a New Highly Efficient MoM Solution

In this paper, a fast converging method for accurate and efficient analysis of the electromagnetic scattering by a zero-thickness perfectly electrically conducting annular ring is presented. An electric field integral equation in the vector Hankel transform domain is obtained by expanding the unknown surface current density in cylindrical harmonics. A fast convergence of exponential type is achieved by means of Galerkin’s method with expansion functions reconstructing the expected physical behaviour of the nth cylindrical harmonic at the edges of the annular ring with closed-form spectral domain counterparts. Moreover, the elements of the coefficient matrix are efficiently evaluated by means of algebraic manipulations and a suitable integration procedure in the complex plane. In order to verify the correctness of the presented method, comparisons with the commercial software CST Microwave Studio are performed.