Double tuned patch antenna design for bandwidth enhancement

A broadband patch antenna design using band pass filter principle is studied. This paper describes a particularly convenient way of feeding the patch with a tuned loop that result in symmetrical patterns over a wide bandwidth. The tuned loop could be seen as a series resonator and its resonant frequency is set to the same as the equivalent parallel tuned circuit representing the patch, two coupled resonators obtain a double-tuned response broadening the bandwidth like a second order band pass filter. The results and design process are given, showing this loop-fed technology is very effective to enhance the bandwidth of patch antenna.