4-Port 2-Element MIMO Antenna for 5G Portable Applications

In this paper, a compact, low-profile four-port, two-element antenna for the 5G Internet of Things (IoT) and handheld applications with height h = 3.0 mm is presented. The antenna structure contains two planar inverted-F antenna (PIFA) elements having the same shapes. Each antenna element has two feeding plates placed at the right angle to each other to make them cross-polarized for the exploitation of polarization diversity, whereas spatial diversity is employed by positioning two antennas diagonally on opposite sides of the antenna structure. For reducing mutual coupling, the etching of rectangular slots on each side of the ground plane beneath the top plate of each element has been done to stop the flow of current between two ports of the same antenna element. Maximum isolation achieved among ports is less than -25 dB, and envelope correlation coefficient is below 0.009 in bands of interest. The minimum frequency range covered by the four ports of this antenna is from around 2.7 to 3.6 GHz for S11<; -10 dB, thus covering expected future 5G band (3300-3600 MHz), and may be used for small portable and handheld the IoT and cellular applications as a diversity/MIMO antenna.