Isolation Improvement in MIMO Dielectric Resonator Antennas

Abstract

A high isolation in a closely spaced multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is proposed in this article. Two rectangular dielectric resonators (DRs) are placed on top of substrate and are capacitively coupled to the microstrip line through rectangular slots. The isolation is achieved by applying a pair of metal strips printed on the lateral walls near the adjacent edges of the DRAs. The realized MIMO DRA has −10 dB impedance bandwidth (IBW) of 11.06%(14.1-15.75 GHz) with an isolation level of −25.5 dB to −32 dB. The realized gain ranges from 8.5 to 9.2 dBi. The performance comparison between the conventional (with no metallic strips) and the proposed design is conducted by keeping the minimum inter-element spacing g=0.1 mm ( 0.005λ0 ). The mechanism of the isolation improvement and the design procedure are discussed in detail.

Keywords: Mutual coupling, Microstrip resonators, Simulation, Resonant frequency, Dielectric resonator antennas, Dielectrics, Microstrip