Amplitude patterns of aperture antennas mounted on circular and square ground planes

The analysis for the far-zone amplitude radiation patterns in E and H planes of a TE₁₁-mode circular aperture antenna mounted on finite circular and square ground planes is presented. The pattern is constructed from the superposition of a wave radiated directly from the circular aperture (in the presence of an infinite ground plane) and a wave diffracted from the edge of the finite ground planes. These patterns are verified with experimental results and those simulated by Ansoft´s High Frequency Structure Simulator (HFSS). Excellent agreement is observed for all cases considered.