A Compact Size and High Isolation Dual-band MIMO Antenna Using EMSIW

A simple and low-profile four-elements dual-band multiple-input multiple-output (MIMO) antenna using an eighth mode substrate integrated waveguide (EMSIW) cavity resonator is proposed for 5G new radio. The dual-band operation is achieved by radiating the edge perpendicular to the EMSIW and an extra slot etched out in the proposed structure. Different variations of the size of radiating edges and slots were carried out, and the simulated results were presented. Finally, the optimized antenna is demonstrated to operate at 2.6 GHz (n41) and 3.5 GHz (n78), having 6-dB impedance bandwidths of 6.55 % and 1.91 %, respectively. The four EMSIW elements are counterclockwise arranged to form the MIMO antenna and achieve good diversity performance. Because of the asymmetric EMSIW structure, their radiation patterns are found isolated from each other, thus improving the diversity. As a result, high isolation (>39dB), and envelope correlation coefficient (ECC) is found to be <0.06 without using a complex decoupling network. The prototype of the proposed antenna is developed, and its performances are measured and found in close agreement with the simulated results.