Isosceles-Right-Triangular SIW-Fed Dual-Polarized Filtering DRA with High Port Isolation

A differential dual-polarized filtering dielectric resonator antenna (DRA) fed by isosceles-right-triangular substrate integrated waveguides (IRTSIWs) is presented in this letter. The out-of-phase TE110 modes of the IRTSIWs excite orthogonal modes in the DRA, resulting in the co-frequency dual-polarization. High isolation between the differential-fed ports is realized with the use of IRTSIW cavities. Then, a bandpass filtering response is realized using the coupling topology. The radiation nulls are introduced at the passband edges to improve frequency selectivity. For demonstration, a prototype is designed and fabricated. The measured results show that the impedance bandwidth is 5.15-5.60 GHz, the gain in the passband is no less than 6 dBi, and the out-of-band suppression is higher than 16 dB. Besides, a high port isolation of more than 78 dB is achieved in the proposed design.