Mutual Coupling Reductions of Dielectric Resonator Antennas without Extra Circuits

This paper describes an effective strategy to reduce the mutual couplings of dielectric resonator antennas without using extra circuits. The strategy is enabled by etching an elliptical cylinder in a cube-shaped dielectric resonator along its diagonal direction. By optimizing the dimension and location of the elliptical cylinder, the mutual coupling of the orthogonal polarizations of the dielectric resonator antenna can be effectively reduced. For demonstration, a cube-shaped dielectric resonator antenna operating at 5.8 GHz is configured with a proper elliptical cylinder drilled in the right position. The simulated results demonstrate the mutual couplings of the orthogonal polarizations can be reduced to -25 dB from 5.6 to 5.95 GHz, where an average of 8 dB mutual coupling reduction can be obtained compared to the one without the ellipse cylinder drilled. The radiation patterns, realized gains, and total efficiencies of the dielectric resonator antenna with the elliptical cylinder drilled can still be maintained, verifying the effectiveness of the proposed strategy to reduce the mutual coupling.