Design and analysis of a compact high-isolation MIMO antenna system for Wi-Fi, bluetooth, and IoT devices

Abstract The design, fabrication, and performance evaluation of a compact, high-isolation two-port MIMO antenna for the 2.4 GHz ISM band are presented in this paper. Constructed on a cost-effective FR-4 substrate, the antenna employs orthogonal polarization diversity and modified rectangular patches to minimize mutual coupling between the two ports. Stepped impedance feed lines and a partial ground plane are incorporated to enhance impedance matching and radiation characteristics. Simulated and measured results demonstrate close agreement, with a return loss (S 11 ) of approximately −30 dB and inter-port isolation (S 21 ) exceeding −22 dB at 2.4 GHz. The MIMO antenna achieves a stable peak gain of 2.75 dBi and radiation efficiency above 85%. Key diversity metrics include an envelope correlation coefficient (ECC) below 0.0004, a diversity gain (DG) greater than 9.99 dB, a channel capacity loss (CCL) below 0.012 bits/s/Hz, a total active reflection coefficient (TARC) below −26 dB, and a mean effective gain (MEG) of approximately −3.0 dB. These characteristics, combined with the antenna’s compact size, render it highly suitable for integration into modern IoT devices and compact wireless communication systems.