High Selectivity Filtering Patch Antenna Using Parasitic Patches

A filtering patch antenna based on parasitic patches is proposed in this paper. The filtering antenna is mainly composed of a driven patch, a parasitic rectangular patch, and a parasitic ring patch. The combination of the driven patch and parasitic rectangular patch can create a radiation null at the upper band edge, while the addition of parasitic ring patch can introduce another radiation null at the lower band edge. The propose antenna exhibits a quasi-elliptic boresight gain response with the help the two radiation nulls. The simulated| S11| of the proposed antenna is less than −10 dB in the range of 0.92-1.08 GHz (16%). Without extra filtering circuits, the antenna achieves an average simulated gain of 9.3 dBi within passband.