The isolation of dual-polarization multiplex microstrip antennas

A simple theory is developed for the analysis of isolation of dual-polarization multiplex microstrip antennas. The analysis is based on the “cavity model” and the “reaction principle”. The shape of the field distribution between the patch and ground plane is assumed to be well approximated by that of the resonant modes of a corresponding magnetic and electric walled cavity. Two element microstrip antennas of various geometries for either transmitting or receiving linearly and circularly polarized waves are studied. Some methods are found to reduce their physical dimensions and to evaluate the isolation between the elements for various configurations