On the Design and Analysis of Compact Super-Wideband Quad Element Chiral MIMO Array for High Data Rate Applications

Abstract

This paper presents a compact, bouquet-inspired, four-element MIMO array for super wideband (SWB) applications. The proposed unit element monopole antenna has compact geometry, and it is deployed by the fusion of an elliptical and circular-shaped radiator. The convoluted geometry and semi-elliptical ground plane, along with the narrow rectangular slit defected ground structure, provides a wide impedance bandwidth. The designed unit cell has the dimensions of 32 mm × 20 mm × 0.8 mm, operates from 2.9 to 30 GHz (S11 ≤ −10 dB) and provides a bandwidth dimension ratio (BDR) of 2894. The proposed low-profile diversity array without any decoupling structures consists of four orthogonally placed, uncorrelated antennas with an inter element spacing of 0.05 λ0, occupies an area of 57 mm × 57 mm and provides dual polarization. The performance metrics of the diversity array were validated for frequencies over ultra-wideband, using mutual coupling characteristics, envelope correlation coefficient (ECC) by far-field radiation, diversity gain (DG), total active reflection coefficient (TARC), channel capacity loss (CCL) and cumulative distribution function (CDF) analysis. The measured mutual coupling over the operating band was less than −18 dB, the ECC was less than 0.004 and the TARC was less than −15 dB, and a better CCL of ˂0.28 bits/s/Hz was achieved by the fabricated antenna.