UWB MIMO antenna implemented with orthogonal quasi-circular slot dipole radiators

In this paper, a very low-profile two-port ultra-wideband antenna for multiple input-multiple output applications is proposed. The antenna is implemented by using two orthogonal quasi-circular slot dipole radiators fed by coaxial lines. The antenna performs from 2 to 10 GHz, with an average peak-gain of 4 dB, and high port isolation, with values around S₂₁ = −20 dB and below. The radiation patterns of both antennas are opposite to each other and hence, the diversity gain reaches values around 20 dB. The low inter-port coupling and low correlation are verified by obtaining the envelope correlation coefficient, which is lower than 0.003. These calculations were made by the S-parameter and far-field methods. The total active reflection coefficient shows that the antenna operative bandwidth does not change for different input signals with random phases, preserving the operation from 2 to 10 GHz. The antenna performance is compared to different state of the art slot configurations, showing advantages to previously published work.