Isolation enhancement using a hybrid technique in an eight-element UWB mimo antenna design

Abstract

An eight-element multiple input multiple output (MIMO) antenna assembly is designed for Ultra-Wideband (UWB) applications. The antenna configuration is based on a peculiar arrangement of the radiating elements. A defected microstrip structure (DMS) is also introduced on the feedlines. The use of a novel technique, the so-called ports-shift, is here discussed. In the proposed antenna, a protruded ground branch structure is employed in combination of three parasitic stubs so as to enhance isolation and impedance matching over the UWB frequency band, respectively. The results show that the presented antenna exhibits a good impedance matching (Sii) which is about-10 dB with a high mutual coupling (Sij)-15 dB, and envelope correlation coefficients (ECC) lower than 0.15. The antenna also exhibits a good diversity gain (DG) of about 9.5 dB, a good efficiency that varied between 56% and 91%, and a total active reflection coefficient (TARC) of less than-20 dB over the entire UWB frequency band. Which makes it a good candidate for UWB applications.