A Decoupling Method for Shared-Radiator Dielectric Resonator Antenna

In this letter, a decoupling method based on mode cancellation is proposed for a shared-radiator dielectric resonator antenna (DRA). In this design, the anti-TE01δ+1 and TE01δ+1 modes are excited simultaneously to achieve decoupling. By loading metal strip to alter the boundary conditions of the DRA, the anti-TE01δ+1 mode with two in-phase half-periods can be excited, which then cancel out with the TE01δ+1 mode. By adjusting the width of the metal strip, the resonant frequencies of these two modes can be tuned to coincide. As a result, the E-field in the DRA that is coupled to the passive port is eliminated, leading to a reduction in mutual coupling. The measured in-band isolation exceeds 24 dB. Additionally, the proposed decoupling method does not deform the radiation performance, as the radiation patterns remain consistent and the cross-polarization level is below –11.5 dB.