Design and analysis of compact size dual polarised ultra wideband MIMO antennas with simple decoupling structure

In this paper, a quad elements, differentially fed, dual polarized Ultra-Wideband Multiple-Input Multiple-Output (UWB-MIMO) antenna system is presented. The unit UWB antenna element is of compact size with the dimensions of 22×24 mm
²
. The proposed MIMO antenna structure consists of two pairs of dual polarized rectangular shape UWB monopole antennas. A simple decoupling structure (DS) comprising of rectangular stubs is optimized with several full wave simulations to improve the isolation among the antennas. The proposed MIMO system exhibits reflection coefficient whose value is less than -10 dB from 4.5 GHz - 11.5 GHz. Different important parameters such as radiation characters, time domain received signals from each antenna element, electric field distribution, envelop correlation coefficient and diversity gain are calculated, analyzed and compared. The diversity antenna system with decoupling structure has shown a significant better performance compared to the system without decoupling structure.