Inset-Fed Octagonal-Shaped Quad-Port MIMO Patch Antenna for UWB Applications.

A compact and novel quad-element inset-fed octagonal-shaped multiple input multiple output patch (QIOMP) antenna with a hexagonal-shaped slot is designed for ultra-wideband applications. The proposed MIMO antenna comprises four identical octagonal-shaped radiating elements. To achieve better diversity performance and low mutual coupling, radiating elements are positioned at the ideal distance. The proposed octagonal-shaped MIMO antenna is prototyped on a Fr-4 substrate with the overall dimensions of 32 × 32 × 1.6 mm³. It achieves an ultra-wide bandwidth (S₁₁ < − 10 dB) of 13.9 GHz, operating from 2.5 to 16.7 GHz, except for the band notch from 8.9 to 9.2 GHz. The proposed antenna has a gain of 3.50 dBi, 4.40 dBi, 6.67 dBi, and 5.22 dBi at 4.8 GHz, 8.1 GHz, 10.5 GHz, and 14.1 GHz, respectively. At the operating frequencies, surface current distribution and radiation patterns are examined. The diversity performance of the QIOMP antenna is evaluated by reviewing several MIMO parameters, including an envelope correlation coefficient < 0.03, a diversity gain > 9.8, the total active reflection coefficient, and channel capacity loss < 0.05 bits/sec/Hz. The simulated and experimentally obtained results are presented and exhibit a high degree of concurrence. [ABSTRACT FROM AUTHOR]