Effects of finite ground plane and substrate permittivity on E- and H- plane Co-polarization patterns of the circular patch antenna

The microstrip circular patch antenna is very popular for mobile and satellite communications applications. In order to have the mechanical strength of this patch antenna, typically a dielectric substrate material is used between the patch and the ground plane. Since the electromagnetic wave is trapped inside the dielectric material, the radiation patterns of any microstrip antenna are affected by the substrate. In this paper, the observation of obtaining nearly-equal co-polar patterns in the two principal planes from circular patch antennas is presented. Especially, with a finite ground plane, radiation patterns in two principal planes are investigated to find a range of the elevation angle for a particular substrate permittivity, in which the E- and H-plane co-polarization patterns are equal.