A Compact Planar MIMO Inverted-F Antenna (PIFA) for Sub-6 GHz 5G Communication and IoT Wireless Networks Applications

A compact eight-port MIMO structure containing planar inverted-F antennas (PIFAs) as radiating elements is designed for 5G cellular communication applications within the sub-6 GHz band. The proposed antenna consists of four radiating elements that are placed at four corners on the same plane of geometry. The overall dimension of the ground plane is considered to be 59 mm x 120 mm to make it convenient for modern smart mobile handsets. Each radiating element has 2-feeding plates, which are situated perpendicular to each other in orientation to make the arrangement cross-polarized, which in turn exploits polarization diversity as well as spatial diversity among the combination of different radiating elements. The patches are structured by embedding rectangular slots in a meandered shape, and the ground plane is configured by introducing rectangular slots and narrow metallic strips. The prototype of the prescribed MIMO PIFA model has been fabricated and experimentally tested. It shows multi-band operations (3.27-3.37, 4.16-4.35, 4.93-5.06, and 5.47-5.68 GHz) within the sub-6 GHz spectrum. The isolation among various patches is observed within the range of -35 dB to -42 dB. The peak gain reaches around 8.1 dBi. The designed MIMO PIFA exhibits superior diversity performance by producing ECC <= 0.0006, DG approximate to 10 dB, CCL < 0.20 bits/Hz/s, and MEG <= -3 dB. Furthermore, the specific absorption rate (SAR) is evaluated according to the standard values of fat, skin, and muscle at 3.3 GHz. The prescribed model maintains acceptable SAR values for 1-g and 10-g tissues, which makes it suitable for smartphone applications.