High‐Performance Quad‐Port MIMO Antenna for Millimeter Wave Communications Using Metamaterial‐Based Unit Cells

ABSTRACT This article shows the creation of a small and effective quad‐port multiple‐input‐multiple‐output (MIMO) antenna for millimeter‐wave (mm‐wave) frequencies to facilitate fifth‐generation (5G) communication technology. The design process began with optimizing a four‐octagonal ring‐shaped monopole patch antenna for the 26–40 GHz frequency band. The antenna has a quarter‐wave transformer (QWT) integrated into a 50 Ω microstrip feed line. The ground plane implements a defected ground geometry (DGG) with rectangular, ring‐shaped, and semi‐circular slots to increase isolation and boost performance. To antenna used semi‐circular slots carved onto the ground plane to produce effective isolation of more than 20 dB throughout its operating spectrum. To lessen the mutual connection between antenna components, so‐called metamaterial structures, five‐unit cells are positioned between each antenna element. With a maximum gain of 7.72 dBi, this antenna provided a 10 dB bandwidth spanning from 26 to 40 GHz, covering the 5G mm‐wave range. Moreover, the incorporation of DGG and metamaterial components successfully decreased mutual coupling, resulting in decreased values of the envelope correlation coefficient (ECC). The applicability of antennas for a range of applications, including smart devices, mobile phones, and sensors in 5G networks, is further shown by the analysis of additional MIMO performance measures in the article, such as channel capacity loss (CCL), mean effective gain (MEG), and diversity gain (DG).