A Novel Coupled Patch Filter Antenna With High Selectivity

In this paper, a filter antenna based on the band-pass filter with high selectivity is designed, which combines with open-ended stubs and short-circuit probes to induce a new coupling path between the feedline and the patch. An electromagnetic-based novel coupled microstrip patch scheme is proposed using two connected inverted F patches and a rectangular patch as the top layer drive patch antenna with an extending bandwidth. Two different rectangular slots are configured in the middle layer achieving the purpose of multiple coupling; while the bandwidth can be effectively controlled by adjusting the size of the rectangular slot. In this way, the proposed antenna would gain passband on both sides, and the two radiation nulls could effectively improve the selectivity of filter antenna. Experiments show that the center frequency of the antenna is 3.83GHz, the impedance bandwidth 12.6%; while the two controllable transmission zeros are located at 3.3GHz and 4.12GHz, respectively, demonstrating the advantages of high isolation and low cross-polarization.