Substrate-integrated-waveguide-fed slotted patch filtering antenna and array with enhanced selectivity

In this paper, a slotted patch filtering antenna fed by substrate integrated waveguide (SIW) cavity is investigated. The microstrip patch (MP) acts as not only a radiator but also the last resonator of the bandpass filter (BPF) for synthesizing the filtering response. Furthermore, a pair of slots is etched on the MP to introduce a controllable radiation null at the upper passband edge without adding additional filtering circuits, resulting in an enhanced filtering response with a sharp band skirt. More importantly, the mentioned way can be easily transferred to design filtenna array. For demonstration, a prototype of 2 x 2 slotted patch filtenna array with a center frequency of 13.6 GHz is designed, fabricated and measured. The measurement results exhibit that the proposed slotted patch filtenna array possesses flat passband gain with a peak gain of 12.9 dBi, an 88% peak efficiency and a radiation null at 14.64 GHz. Good agreement between the simulation and measured results is observed.