SIW Based Cavity Backed Self-Quadplexing Slot Antenna

Abstract In this paper, a low profile substrate integrated waveguide (SIW) based self-quadplexing antenna with high isolation is demonstrated for multiband wireless applications. Here the SIW based resonator cavity is integrated with an “X”-shaped resonator and formed the four quarter mode cavities having the individual microstrip feed lines. Each quarter mode cavity consists of “V”-shaped slots of different lengths; are in front to feed line and produce the four distinct resonant frequencies at 7.8 GHz, 8.5 GHz, 10.2 GHz, and 10.6 GHz, respectively. The working principle depends upon the perturbation of higher-order modes in a particular quarter mode cavity. The minimum intrinsic isolation of below than −26dB is attained between any of the two input ports by adequately modifying the antenna dimensions. Hence, a single antenna consists of four individual signals without interfering with each other, which determines the self-quadplexing property of the antenna. The proposed antenna is realized for maximum efficiency and minimum value of frequency ratio. The measured gain of the proposed antenna is 4.5 dBi, 5.28 dBi, 7.1 dBi, and 7.4 dBi at the four resonant frequencies, respectively.