Broadband dual-polarized proximity coupled circular patch antenna

This paper presents the design and results of a novel broadband dual-polarized circular patch antenna. The antenna is fed by microstrip lines through proximity coupling, and H-shaped slots are cut in the ground plane below the feed lines for enhancing the coupling between the patch and the feed lines. By using only a single circular microstrip patch, the prototype antenna yields bandwidth of 21.5% and 25.9% at the input ports 1 and 2, respectively. The isolation between two input ports is below -30 dB across the bandwidth. Good broadside radiation patterns are observed, and the cross-polar levels are below -20 dB at both E- and H-planes. Due to its simple structure, it is easy to form arrays by using this antenna as an element.