Abstract
Abstract
This paper presents a compact 4×4 MIMO antenna designed to operate at triple-band frequencies of 28, 29.58 and 32.82 GHz. The antenna is fabricated on a Rogers RT 5880 substrate with overall dimensions of 13×13×0.254 mm³. The antenna operates over three frequency bands: 27.70-28.32 GHz, 29.44-29.91 GHz, and 32.72-33.10 GHz, with realized gains of 7.8 dBi, 4.8 dBi, and 7.6 dBi, respectively. Mutual coupling between the antenna elements is effectively reduced by the combined effect of orthogonal element orientation and a fan-shaped slot in the ground plane, yielding isolation levels > 22dB across the three operating bands. The surface current distribution analysis of the perturbed ground plane is presented to demonstrate the decoupling mechanism between the adjacent radiating elements. The antenna exhibits excellent diversity performance, with an envelope correlation coefficient (ECC) below 0.004, a diversity gain (DG) close to 10 dB, a mean effective gain (MEG) below −3.5 dB, and a channel capacity loss (CCL) below 0.26 bits/s/Hz. The calculated antenna results are validated with the measurements and found suitable for 5G smartphones, IoT systems and vehicular communications.