An Elliptical Shaped Wideband MIMO Terminal Antenna with Improved Isolation and Radiation Efficiency for 5G mmWave Applications

A quad-port wideband, multiple-input-multiple-output (MIMO) antenna system is discussed here for millimeter wave applications. The proposed antenna consists of a microstrip line, an elliptical shaped patch, a thin rectangular line, and a radial stub. The intended unit antenna is electrically large size of $1.93 \lambda_{0}$ $\times 2.07 \lambda_{0} \times 0.07 \lambda_{0}$ at 28GHz. The modified radiating structure fed by a microstrip line with a partially ground plane is used here as a single radiating element. The proposed wideband antenna exhibits an impedance bandwidth of (24 - 32 GHz) 28.57%, radiation efficiency > 95% and good radiation characteristics. Due to the orthogonal arrangement of the radiating elements, the MIMO antenna has been transformed, which offers high isolation (>25 dB) and better polarization diversity performance. Both the diversity gain (DG) and the envelope correlation coefficient (ECC) are examined and determined to be within acceptable parameters.