An efficient technique for analyzing multiple frequency‐selective‐surface screens with dissimilar periods

This Letter presents an efficient technique for analyzing multiple frequency‐selective surfaces (FSSs) with noncommensurate periodicities based on the discrete plane‐wave spectrum (DPWS) expansion method. In this method, the tangential electric fields at the interfaces of the screens are first expanded in a set of transverse electric and transverse magnetic waves, and the responses of the individual FSS screens are derived for each of these waves. The transmission and reflection characteristics of the composite structure are then computed in an iterative manner, circumventing the need for matrix inversions, which can be extremely expensive in terms of CPU time and memory for noncommensurate FSSs. Representative numerical examples are presented to illustrate the computational advantage gained by using the proposed approach as opposed to the conventional generalized scattering matrix technique.