Improving the performance of a patch antenna array by using photonic bandgap structures at X-band

A proposed three-layered patch antenna array combined with Uniplanar Compact Photonic Bandgap structures (UC-PBG) is presented to avoid non-desired radiations from the feeding structure and to mitigate the surface propagation modes, increasing the radiation efficiency, and reducing the parasitic lobes. The array is fed by electromagnetic proximity, implemented by a stripline network below the radiators. The array is designed to operate at of 10 GHz and is surrounded by UC-PBG structures. This configuration also helps to increase the bandwidth by keeping the electric field and the surface current stable around the radiators, reducing the variations of the impedance on a wider bandwidth. Also, the UC-PBG structures attenuate the surface propagation modes, lowering the parasitic lobes by almost 7 dB and reaching measured radiation efficiency higher than 80%. The patch array gets an operational bandwidth of 2.5 GHz, with a measured gain of 24 dB. The fractional bandwidth is 25%.