Enhanced Isolation Dual-Port MIMO Antenna for n77/78/79 Sub-6 GHz 5G NR Applications

A miniaturized dual-port multiple-input multiple-output (MIMO) antenna, sized <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$28 \text{mm} \times 28 \text{mm} \times 1.6 \text{mm}$</tex>, has been developed for sub- 6 GHz 5 G NR operations covering n77, n78, and n79 bands. The proposed design incorporates two identical radiating elements and an open-ended hollow circular ground structure incorporating a pair of rectangular slots. The modified ground structure greatly affects impedance matching, and electromagnetic field distribution. As a result, enhancements are observed in the impedance bandwidth, isolation, and other MIMO characteristics. The antenna demonstrates a simulated impedance bandwidth of 3.45-5.47 GHz. An isolation level exceeding 19 dB is maintained throughout the target spectrum. Additionally, the results further confirm that the antenna exhibits excellent MIMO functionality in terms of envelope correlation coefficient (ECC), diversity gain (DG), and peak gain. An ECC value below 0.015, a diversity gain exceeding 9.9990 dB, and a peak gain of 3 dBi were achieved.