A Circularly Polarized 2×2 MIMO Antenna with Defected Ground Plane and Reduced Mutual Coupling for Wi-Fi Applications

This paper describes the design and construction of an economical circularly polarized 2x2 multiple input multiple output (MIMO) antenna for Wi-Fi applications. The dimension of the antenna measures to 1.3λ x 1.3λ. The antenna consists of a tapered rectangular patch outlined with a U-shaped strip and two inverted L-shaped slots engraved inside the rectangular patch. The designed footprint of the antenna is 1.3λ × 1.3λ, where λ is free space wavelength at 3.68 GHz. The proposed MIMO antenna exhibits circular polarization with an axial ratio of 1.86dB at 3.68GHz and has an impedance bandwidth of 142 MHz (3.62 – 3.76 GHz). The proposed MIMO antenna is constructed on an FR-4 substrate which is cost effective yet efficient for the desired application. The antenna exhibits an average gain of 1.405 dB, efficiency of around 60% and nearly omni directional radiation patterns in the desired band.