Finite ground plane effects on broad-band dual polarized patch antenna properties

Effects of finite ground plane on the isolation and radiation properties of a broad-band dual-polarized aperture-coupled patch antenna are experimentally investigated. The dual-polarized patch antenna has a thick air substrate for broad-band operation (>16% for both polarizations) and is excited by microstrip lines through two H-shaped coupling slots. Results show that by selecting suitable ground-plane dimensions, isolation between the two feeding ports can be greatly enhanced by about 10 dB, and the cross-polarization level in the E and H planes can also be improved by about 10 and 5 dB, respectively. Also, the impedance bandwidth increases with decreasing ground-plane dimensions.