A Compact 2 Element MIMO Antenna for UWB Applications

Abstract

A novel compact 2 element MIMO micro-strip patch antenna for UWB applications is presented in this paper, designed in CST Microwave Studio. The geometry is symmetrical having a dimension of $\mathbf{25}\times \mathbf{40}\times \mathbf{1}\ \pmb{mm}^{\mathbf{3}}$ with FR-4 dielectric material used as substrate. It is composed of two round shaped radiators with four slots making hexagonal shape and one plus-shaped slot, fed by a micro-strip feed line with $\mathbf{50}\ \Omega$ impedance. The analysis of a design shows that the achieved $\pmb{S}_{\mathbf{11}}$ and $\pmb{S}_{\mathbf{12}} < -\mathbf{10\ dB}$ from 3.39 GHz to 9.1 GHz reflecting UWB characteristics. The diversity performance for the MIMO antenna has also been studied with the envelope correlation coefficient, which is less than 0.003 and the diversity gain is ~10dB. The observed realized gain is $>\mathbf{2.5\ dBi}$ and the simulated total efficiency of the system is approximately 93%.