Millimeter-Wave Quad-Port Multiple-Input Multiple-Output Dielectric Resonator Antenna Excited Differentially by TE20 Mode Substrate Integrated Waveguide

In this paper, a differentially excited quad-element multiple-input multiple-output (MIMO) dielectric resonator antenna (DRA) is proposed for millimeter-wave applications. In the proposed design, the rectangular DRA is differentially excited in the $TE_{1\delta 1}^{y}$ mode using the dual-slot configuration located on the top wall of $TE_{20}$ mode substrate integrated waveguide (SIW). The proposed MIMO configuration offers both spatial and polarization diversities. For all the four ports, the impedance bandwidth of the proposed antenna is 3.2% (27.5-28.4 GHz), covering the 5G frequency spectrum. The isolation between the input ports is better than 40 dB throughout the operating bandwidth. The antenna radiates along the broadside direction having the cross-polarization level below -30 along the zenith. The peak gain and radiation efficiency of the proposed antenna is 4.2 dBi and 86%, respectively at 28 GHz. Moreover, the diversity performance is found to be good having low value of envelope correlation coefficient across the band-width. The proposed antenna could be the potential candidate for next generation 5G communication system.