Moxon-Based Broadband Circularly Polarized Antennas

To meet the challenges of modern radio communication systems, antennas need to be optimized for higher gain, broader bandwidth, smaller size, defined radiation pattern, polarization, and lower cost. The Fano-Chu limits have been extended to larger structures with more conducting elements to yield higher gain. A circularly polarized antenna structure has been developed for satellite communications, RFID tag reader, GPS, and Base Station antennas for UMTS-FDD and E-UTRA-FDD. A coupler element has improved the proposed topology to improve circular polarization gain performance. New elements have been designed to optimize gain, lower cross-polarization, and maintain a low profile with adequate bandwidth.