A Compact $4\times 4$ MIMO Antenna Using EMSIW

A compact and planar four-element multiple-input multiple-output (MIMO) antenna using an eighth-mode substrate integrated waveguide (EMSIW) cavity resonator is proposed for the 5G new radio. The antenna radiates with a peak gain of 3.1 dBi, operating at 3.5 GHz. Four EMSIW elements are placed orthogonally in an anticlockwise direction in the proposed MIMO antenna to achieve polarization diversity. In addition, the asymmetrical radiation property of the EMSIW element is utilized to attain pattern diversity, subsequently to deliver high MIMO diversity performance. The MIMO diversity parameters like isolation and envelope correlation coefficient (ECC) are realized <-20 dB and <0.2, respectively, without using any extra decoupling network. Thus, presenting compact and low-cost antenna design satisfying the diversity requirements.