Broadband Patch Antennas Fed by Novel Tuned Loop

A novel tuned loop feed for patch antennas is described. The arrangement provides a symmetrical excitation of the patch with a double tuned response with enhanced bandwidth. The tuned loop together with the patch can be seen as a band pass filter comprising a series resonator and parallel resonator tuned to the same frequency. The tuned loop can easily be implemented as a microstrip PCB. A dual polarized patch antenna can be designed for diversity reception using this technique. Measured results are given, showing that this feed is effective in broadening the bandwidth of patch antennas. This configuration is a good candidate for radiating elements in cellular base station antennas.