Reconfigurable Single Port Antenna With Circular Polarization Diversity

New design of a single feed reconfigurable circular 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 the right-hand circular polarization (RHCP) and the left-hand circular polarization (LHCP) are generated. These patterns are used for diversity reception in indoor fading channel for wireless LAN applications. Detailed design of the antenna is described. Experimental results for return loss, radiation patterns, radiation efficiency, antenna gain, axial ratio and the diversity performance in Rayleigh fading channel are presented.