Design of Compact Antenna Array for MIMO Implementation Using Characteristic Mode Analysis for 5G NR and Wi-Fi 6 Applications

In this paper, we present a compact antenna for 5G new radio (NR) and Wi-Fi 6 applications. Using characteristic mode analysis (CMA), two orthogonal modes have been separated and then a gap-coupled shaped feed-line has been used to excite the radiator. An open stub is added to achieve the wide operating bandwidth of the antenna. The size of a single antenna element and the 1
$\times $
2 array-unit (AU) are 20
$\times $
21.5 mm2 and 40
$\times $
21.5 mm2, respectively. The operating and fractional bandwidths (FBW) of the AU are 5.18–7.71GHz and 39.25%, respectively. The proposed AU is used to develop a number of radiating element-independent multiple-input-multiple-output (MIMO) antennas comprising of 2AUs, 4AUs, and 8AUs with identical electrical characteristics and good isolation (
${I}$
) ≥ 18.8 dB. All the AUs have realized gain ~ 3.0 dBi, and the total antenna efficiency ~ 70% making it suitable for the single-user MIMO (SU-MIMO) and multiple users MIMO (MU-MIMO) needed for Wi-Fi 6 applications. To show the application of these antennas, the deployment scenario of a 16AUs MIMO antenna on a large size ground plane which mimics the smart TV panel and router chassis, etc., is also presented. These AUs may find potential applications in radiator-number independent MIMO systems.