SIW Cavity-Backed Self-Triplexing Antenna with T-Shaped Slot

In this paper, a new design of planar cavity-backed self-triplexing slot antenna is presented. The planar circular cavity is realized by using substrate integrated waveguide (SIW) technology. A T-shaped radiating slot is etched on the top metal cladding of the SIW which segments the cavity into three parts. When each of these segments is excited individually by three microstriplines, the cavity produces the three distinct resonant frequencies of 5.6, 6.64 and 6.95 GHz. In order to improve intrinsic port isolations, three shorted-vias are introduced near the radiating slot. By properly adjusting the antenna parameters, a high isolation of better than 25 dB is realized between any of two ports which supports to introduce the self-triplexing phenomenon. The antenna takes the advantages of the low-profile, compact configuration, ease of fabrication and the capability of planar integration. Finally, the proposed is fabricated and experimentally validated. The experimental results agree well with simulated counterparts.