A Patch Antenna Based on Filtering Feed Structure With Cross-Polarization Suppression

This paper investigates a filtering patch antenna with cross-polarization suppression. The patch antenna is fed by a filtering feed network, which consists of two vertical C-shaped microstrips arms printed on four PCB layers and two vertical probes. In the proposed design, a novel feeding scheme excites patch mode to achieve an operating bandwidth of 13.4%, with an average antenna gain of 7.2 dBi. Meanwhile, the filtering feed network filter the energy fed to the antenna, thus the antenna has a good selectivity. Furthermore, owing to the two pairs of vias in the substrates with out of phase current, the cross-polarization of the antenna can be suppressed. The total size of the filtering patch antenna is
$0.38\lambda 0\times 0.38\lambda 0\times 0.06\lambda 0$
, which is almost the same as the footprint of a traditional patch antenna.