I. Introduction
In the past few years, the fifth generation (5G) technology has been established worldwide and advancing for its capabilities like high data rates, broader bandwidth, ultra-low latency, and huge network capacity [1]. While the 3.5 GHz frequency band is licensed as the 5G mid-band by most of the countries of the world because of its ability to transmit data at a longer distance than the 5G high band of 28 GHz [2, 3]. On the other hand, in recent years, the 5.8 GHz ISM band has become more popular than the 2.4 GHz ISM band because of its higher data transmission rates [4– 7]. Additionally, most of the antenna researchers are considering the multi-input-multi-output (MIMO) capable antennas for the recent and upcoming wireless communication systems because of their benefit over multipath fading [8– 10]. Moreover, the MIMO antennas can convey more data without requiring additional bandwidth by using spatial multiplexing [11]. Furthermore, through the use of many antennas and signal propagation phase control, MIMO antenna technology enables operators to electronically adjust an RF signal’s directivity [12, 13].