SIW Resonator-Based Duplex Filtenna

In this communication, a low-profile single-layered duplex-filtenna scheme is proposed by using two feeds, and a common substrate integrated waveguide (SIW) cavity. A rectangular slot is carved on the top of the cavity along the narrower side of the SIW, which splits the cavity into two unequal parts. Each part behaves as a half-mode SIW (HMSIW) resonator which radiates with the help of an additional longitudinal slot and open-end of HMSIW when excited with corresponding feed. Also, two vias have been loaded along the broad side of the transverse slot to tune the impedance bandwidth and improve the selectivity in the passbands. The working process of both HMSIW resonators is similar, thus similar type of electrical performance is expected. By properly optimizing the locations of these vias and transverse-slot dimensions, high isolation between input ports is realized. To validate the proposed concept, design has been fabricated and measured. The measured results show good agreement with the simulated counterparts. The measured result shows that the design exhibits impedance bandwidths of around 3.0% (8.63–8.88 GHz) and 4.2% (9.26 $ - $ 9.66 GHz) for lower and upper-frequency pass channel, respectively. The measured average realized gains in the broadside direction are 3.51 and 4.10 dBi, respectively.