A Wideband Differential-fed Dual-Polarized Filtering Patch Antenna With High Isolation

A wideband differential-fed patch antenna with high isolation and high selectivity is presented. The differential-fed method is used to provide the antenna with high polarization isolation characteristic. A parasitic patch is adopted in the design not only to improve the impedance bandwidth, but also to generate a radiation null at the upper band-edge. Filtering response is improved by etching slots and loading resonant stubs on the feeding lines. Simulated results show that the proposed DFDP filtering antenna has an operation band of 34.16% (from 3.86 to 5.45 GHz) for |Sdd11| < -10 dB and a maximum gain of 9.64 dBi, and the cross-polarizaiton level is below -27 dB. Moreover, a high out-of-band gain-suppression level which reaches 21.9 dB is also obtained.