Single-Port Circular-Patch Polarization Diversity Antenna

New design of a single feed patch antenna with polarization pattern diversity is presented. The radiating circular patch, printed on a thin substrate, is supported by non conductive posts on a conducting ground plane and is excited with a capacitively coupled feed. Wideband impedance matching is achieved. The pattern diversity is generated using two switch parasitic pins between the circular patch and the ground plane. By optimizing the position of the switching elements, two orthogonal patterns with right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) are generated. These patterns are used for diversity reception in indoor multipath fading channel for wireless LAN applications. Design of the antenna is described. Experimental results for return loss, radiation patterns, and diversity performance in Rayleigh fading channel are presented.