Isolation Improvement Using Asymmetric Radiators and Ground Plane Diversity Mechanism in a Six-Element UWB MIMO Antenna Design

Abstract

—A compact six elements MIMO antenna is presented for UWB applications. The proposed MIMO array consists of non-identical monopole antennas with distinctive ground planes so as to nullify mutual coupling amid side-by-side elements. Also, by properly placing the antenna elements exploiting cross polarization diversity, a good isolation throughout the operating bandwidth is achieved. Moreover, two parasitic inverted L stubs in combination with small rectangular stubs are employed near the middleplaced radiators and corner placed radiators, respectively, in order to extend the frequency band and enhance the impedance matching. Results show a good reflection coefficient about −10 dB, a high isolation > 20 dB, an envelope correlation coefficients < 0.15, a high diversity gain equal to 9.3, and finally, a maximum value of efficiency for both used antenna elements which is about 78% and 60% with 6 and 5 dBi of gain, respectively. They validate the proposed MIMO antenna efficiency for UWB diversity applications.