Spectral Method of Moments for Planar Structures With Azimuthal Symmetry

An efficient method-of-moments formulation is proposed for the analysis of planar structures in the presence of azimuthally symmetric fields. Boundary integral equations are derived for TM and TE polarizations, assuming as a reference structure a metal plate with a finite number of concentric annular slots placed above a stratified medium. The equations are discretized with a Galerkin testing scheme in the Fourier-Bessel domain, adopting suitable sub-domain basis functions that ensure a very rapid convergence of the involved spectral integrals. Numerical validation is provided by comparison with state-of-art simulation software, considering planar antennas with omnidirectional radiation patterns, in order to show the accuracy of the proposed formulation.