A Reconfigurable Microstrip Patch Antenna with Frequency and Circular Polarization Diversities*

A novel microstrip patch antenna with both frequency and circular polarization diversities is presented. The proposed antenna consists of two parts, a patch with two orthogonal slots on the upper substrate and a 3dB hybrid coupler fed structure which printed on the lower substrate. Two groups of diodes placed across the orthogonal slots are utilized to achieve frequency reconfigu-ration. Another two diodes, placed between the input port of the antenna and the 3dB hybrid coupler, are utilized to switch between Left-hand circular polarization (LHCP) and Right-hand circular polarization (RHCP). Full wave simulation is used for the antenna analysis, and a prototype of the antenna with an integrated Direct current (DC) bi-asing circuit has been fabricated and measured. The results verify the reconfigurable characteristics of the antenna and demonstrate a good candidate for wireless communication applications.