Design and Analysis of a MIMO Antenna with Circular Polarization for Sub-6 GHz 5G Applications

In this paper, a multiple-input multiple-output (MIMO) square microstrip patch antenna with four elements for circular polarization (CP) is presented. Every antenna of this MIMO antenna is made of a patch and a microstrip feed line. Two T-shaped stubs are added diagonally with the patch antenna for obtaining CP. In this MIMO antenna, four elements take place orthogonally from their neighbor. Three different forms of slots are implemented on the ground for achieving a wider 3 dB axial ratio (AR) bandwidth as well as a minimum AR value. The minimal value of S<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf> is found at a frequency of 3.50 GHz. The frequency spectrum of AR is 3.37–3.98 GHz. All the achievable isolation values are less than -30 dB. For antennas 1 and 3, and antennas 2 and 4, the gain values of this MIMO antenna are 7.39 dBic and 7.34 dBic, respectively. The noteworthy results are attained for both diversity gain and the envelope correlation coefficient. The design and simulations are accomplished by computer simulation technology (CST). The achieved outcomes make this MIMO antenna more suited for sub-6 GHz 5G applications.