A Filtering Patch Antenna With Reconfigurable Quad-Polarization Diversity

This brief presents a filtering patch antenna with reconfigurable quad-polarization diversity. By loading parasitic patches and a Jerusalem-cross-shaped metal strip on a patch antenna, two radiation nulls are introduced to realize frequency selectivity. Then, to achieve reconfigurability, a feeding network with four switchable output modes is proposed. By switching the PIN diodes, the antenna realizes vertical linear-polarized (V-LP), horizontal linear-polarized (H-LP), left-hand circular-polarized (LHCP) and right-hand circular-polarized (RHCP) radiations while maintaining its intrinsic filtering characteristic. A prototype operating at 2.28 GHz is fabricated, and the measured 10-dB overlapped bandwidth of the four polarization states is 5.7%. The peak gains for the four states are higher than 6.65 dBi, and the overlapped 3-dB AR bandwidth is 7.89%.