VECTOR SPECTRAL-DOMAIN METHOD FOR THE ANALYSIS OF FREQUENCY SELECTIVE SURFACES

—Standard spectral-domain method,(SDM) is one of the popular approaches to analyze frequency selective surfaces (FSS). However, it is inherently incapable of handling normal incidence because of its dubious definition of excitation fields, reflection and transmission coefficients using z-component of vector potentials. Moreover, as far as the author knows, it has never been applied to analyze FSS with gangbuster arrays. In this paper, an improved SDM, the vector spectral-domain method, is presented. By proving the equivalence of the spectra of unit cell current and element current, the scattered field from FSS structures is formulated in terms of spectral- domain element current instead of spectral-domain unit cell current. Galerkin’s method is applied to obtain the unknown,induced surface current. Well-established definition of excitation fields, reflection and transmission coefficients is adopted. Extensive experimental validation has been conducted.