3-D Eight-Port Ultrawideband Antenna Array for Diversity Applications

This letter presents an eight-port, multiple-polarization, ultrawideband (UWB) diversity antenna array. The unit-cell antenna is constructed from a basic square monopole antenna. With suitable modifications in the radiating plane and the ground plane, the unit-cell antenna is designed to operate between 2.9-12 GHz to cover the entire UWB range. The designed UWB radiator is then replicated within a small space to generate triple polarization. The proposed diversity antenna array consists of eight uncorrelated antennas, of which four are horizontally oriented and the remaining four are vertically oriented to achieve polarization diversity. Diversity performance metrics such as envelope correlation coefficient, apparent diversity gain, and effective diversity gain are evaluated and presented. The prototype diversity antenna is fabricated, and experimental results are presented.