Analysis of multilayered FSS by efficient computation of generalized scattering matrix

Frequency selective surfaces (FSSs) have been an active subject in modern applied electromagnetics. These surfaces comprise periodically arranged metallic patch or aperture elements within a metallic screen, usually on a dielectric interface. To tailor the spectral response with more flexibility, composite structures formed by many layers, each layer being either a periodic surface or a homogeneous slab, are often used. For these multilayered structures, cascade connection of generalized scattering matrices (GSM) has been proved to be convenient and efficient. However, the calculation of the GSM for each interface is usually made by computing the scattering parameters independently for each incident harmonic, and therefore very time-consuming. It is the purpose of the present paper to give a method to compute the GSM efficiently. By the method introduced, the S-matrix of a periodic surface can be obtained with almost equal computer effort as required for the computation of a single scattering parameter of the matrix.