Circularly-polarized four-port self-decoupling high-performance THz MIMO antenna for terahertz communication

This study presents the results of co-axial feed circularly-polarized terahertz (THz) four-element multiple-input-multiple-output (MIMO) antenna. The antenna is built on polyimide substrate of size 1.05λ x 1.05λ x 0.055λ (‘λ’ is wavelength calculated at resonance frequency), provides radiation between 3–3.45THz. The position of the co-axial feed is carefully optimized for circular polarization. The simulated 3dB-axial ratio bandwidth of the antenna measures from 3.05–3.15THz. The peak gain of the proposed CP antenna is 5.82dBi at 3.3THz with 85.9% peak radiating efficiency at 3.2THz. The MIMO elements are oriented orthogonally to achieve orientation diversity and thereby reducing mutual coupling. The parameters of the MIMO antenna are evaluated such as envelope correlation coefficient (ECC), diversity gain (DG), isolation and channel capacity loss (CCL). The simulated ECC and DG value are < 0.0015 and