Receiving and Scattering Characteristics of Circular Patch Antenna Array

Abstract

This paper examines the receiving characteristics of an infinite array of circular patch antennas. The patches are located on a layer of dielectric, which is situated on a ground plane. Each patch is connected to a load impedance at the ground plane through a feed pin. The entire structure is illuminated by an incident plane wave. The receiving characteristics are obtained over a frequency range of 3 to 1 or more, so that off-resonance behavior and the effect of higher order resonances on the antenna characteristics are important, and need to be accurately determined. The receiving array is decomposed into scattering and transmitting cases which are solved separately, and reconstituted to give the receiving case. Accurate solutions of these cases over a wide frequency bandwidth are pursued, including full effects of the feed pin. The solution is approached through a Green's dyadic formulation for sources and induced fields both in the dielectric region and on the dielectric-cover interface. Galerkin's method is used to solve for the currents on the patch and feed pin surfaces. The current on each patch surface is expanded as a summation over a set of smooth continuous currents along with a singular current distribution which models the current diverging from the feed pin onto the patch. The smooth currents are separated into radial and azimuthal components which vary in the azimuthal direction sinusoidally, and in the radial direction as Tchebychev polynomials modified by an appropriate edge factor. Numerical solutions for received power and input impedance are obtained.