Análise do espalhamento em superfícies seletivas em frequência com multicamadas dielétricas anisotrópicas.

Abstract

This work presents a theoretical analysis and experimental/numerieal results for the scattering, characteristics of frequency selective surfaces using perfect conducting patches. The structures are composed by anisotropic dielectric substrates. The analysis is developed using the equivalent transmission line approach in combination with the Galerkin method to determine the transmission and reflection characteristics. Furthermore, the analysis uses the equivalent transmission line approach which allows to model the structure as an equivalent circuit and, applying the transmission line theory, to determine the dyadic Green's function. This function relates the incident fields with the surface current densities. These fields are determined by the incident potentials by imposing the field continuity at the dielectric interfaces. The Galerkin method is used, allowing the numerical determination of the unknown weighting coefficients and, as a consequence, the current surface densities that are expanded in terms of the known basis functions multiplied by the weighting coefficients. The determination of these functions allows the determination of the scattered fields on the top and bottom of the structure and, consequently, the determination of the transmission and reflection characteristics of these structures. In the analysis, three different types of patch geometries are assumed. In addition, anisotropic dielectric substrates are considered. The anisotropic substrates are assumed to be uniaxial ones, and the optical axis is considered to be along the direction perpendicular to the dielectric interfaces. In this work, numerical and experimental results are presented for the reflection and transmission characteristics. Comparisons were made with other results presented in the literature. A good agreement was observed between these results for frequency selective surfaces using isotropic substrates. Some suggestions are presented for future works on this subject.