Equilateral triangular dielectric resonator based co-radiator MIMO antennas with dual-polarisation

In this study, two types of dielectric resonator antennas (DRAs) with dual-polarisation are proposed and investigated for multiple-input multiple-output (MIMO) applications. The first design is a dual-slant polarised DRA and exhibits the measured impedance bandwidth of 8.2% (5.27-5.72 GHz) and 11.2% (5.05-5.65 GHz) for Port1 and Port2 , respectively. Across the operating frequency band, the isolation between the input ports is better than 22 dB and the measured gain of the antenna varies in the range of 5.99-6.38 dBi. The second design developed here is a dual-linearly polarised DRA which is able to provide horizontal and vertical polarisations and is realised by integrating a two-stage rat-race coupler with the DRA for excitation purpose. In this case, the measured impedance bandwidths are 11.81% (5.18-5.83 GHz) and 15.18% (4.93-5.74 GHz) for Port1 and Port2 , respectively, and the inter-port isolation is better than 20 dB throughout the operating frequency band. The antenna exhibits the measured gain variation of 5.94-6.48 dBi for Port1 and 5.54-5.86 dBi for Port2 . Furthermore, for both the antennas, the envelope correlation coefficient is below 0.0004 throughout the bandwidth and the total active reflection coefficient is better than -10 dB, confirming the good diversity and radiation performance.