Electromagnetic Scattering from Microstrip Patch Antennas and Spirals Residing in a Cavity

ABSTRACT

A new hybrid method is reviewed for the analysis of the scattering by conformal antennas and arrays comprised of circular or rectangular elements. In addition, calculations for cavity-backed spiral antennas are given. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at 0(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of largo–size structures with remarkable efficiency. In this paper, we describe the method’s formulation and implementation for circular and rectangular patch antennas in the presence of lumped loads and resistive sheets/cards. Many computational examples for rectangular and circular patch configurations are presented which demonstrate the method’s versatility, modeling capability and accuracy.