Compact Wideband Four Element Optically Transparent MIMO Antenna for mm-Wave 5G Applications

A four-element compact wide-band optically transparent MIMO antenna with a full ground plane is proposed. The four elements transparent MIMO system has a compact size of 24 × 20 mm
²
with the undivided ground plane as most of the real-time systems demand a common reference. The complete antenna system achieves around 85% transparency due to a combination of AgHT-8 and Plexiglas which forms the transparent conductive patch/ground and substrate, respectively. The antenna geometry leads dual-band operation ranging from 24.10 - 27.18 GHz (Impedance bandwidth = 12%) and 33 - 44.13 GHz (Impedance bandwidth =28.86$ %) targeting the mm-wave 5G applications. The 4-element antenna system achieves isolation between inter-elements >16 dB and maximum gain value of greater than 3 dBi with more than 75% efficiency. The proposed transparent MIMO antenna is evaluated in terms of diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC), and mean effective gain (MEG) where decent MIMO performance with isolation more than >16 dB between the adjacent and other elements is achieved. Transparent MIMO antenna achieves directional patterns for the operating band with the value of DG >9, ECC <; 0.1, TARC value less than -15dB, and the ratio of MEG within the agreed limit of ±3 dB confirming acceptable MIMO/diversity performance.