An SIW Cavity-Backed Self-Diplexing Antenna

A novel and simple design of a substrate-integrated waveguide (SIW)-based self-diplexing antenna is presented in this letter. The SIW cavity is fed by two individual microstrip feed lines. The two transverse slots of different lengths, which radiate at two distinct resonant frequencies, are etched on the top surface of the cavity. A high isolation (better than 27.9 dB) is achieved between two ports, which leads to obtaining the self-diplexing characteristic of the antenna. The proposed antenna offers a gain of 3.56 and 5.24 dBi at 8.26 and 10.46 GHz, respectively. The antenna exhibits independent frequency tunability at both the operating bands.