Quad ports dielectric resonator antenna with simple feed network and high gain performance

Abstract

This paper presents a quad-port multiple-input multiple-output (MIMO) single cylindrical dielectric resonator antenna (CDRA) for X-band applications. This approach is mainly based on selecting the proper feeding structure for each port as well as implanting vertical metallic vias (VMVs) to diminish the mutual coupling over a wide bandwidth. Two orthogonal apertures and two vertical probes are utilized as feeding structures to realize good isolation between all port combinations. For coupling mitigation between port1 and port2 that is due to the field distribution of the excited modes at these ports, four VMVs are inserted between them in appropriate positions to produce field orthogonality along wide bandwidth. The excited modes inside the proposed CDRA are $H{E}_{52\delta +2}^x$,$H{E}_{52\delta +2}^y$, HE_{32δ + 2}, and TM_{12δ + 2}. Isolation better than -15 dB is attained across the overlapping band of 340 MHz (4 %); from 8.2 to 8.54 GHz. Moreover, the proposed DRA provides a gain of 5.17, 7.21, 7.77, and 7.78 dBi for the four ports at 8.45 GHz and the total efficiencies at all ports are from 65 to 85 % across the operating band. The MIMO performance of the proposed design shows a good envelope correlation coefficient (ECC), diversity gain (DG), total active reflection coefficient (TARC), channel capacity loss (CCL) and mean effective gain (MEG) through the whole band for all ports.