Analysis of multilayer frequency selective surfaces on periodic and anisotropic substrates

A full-vector semi-analytical method is presented for the analysis of a frequency selective surface consisting of patches printed on substrates having periodic inhomogeneity and both electric and magnetic anisotropy. Based on a multiconductor transmission line model for the substrate, a matrix is obtained which can be considered as the Green's function matrix. The resulting integral equation becomes a series equation for a periodic structure. The equation can be solved by the method of moments with sub-domain rooftop basis functions and Galerkin testing functions. Several examples are analyzed using this technique. Numerical results demonstrate the effect of periodic substrates and anisotropy on the performance of the frequency selective surfaces. It is shown that using periodic substrates brings some degrees of freedom for better controlling the electromagnetic characteristics of the device. For some special cases, comparisons with measurement results and Maxwell solvers are performed.