Fractal loaded planar Super Wide Band four element MIMO antenna for THz applications

In this paper, a compact Super Wide Band (SWB) four element multiple-input-multiple-output (MIMO) antenna having an overall dimension of 125 $\mu$m$\times 125\mu$m is presented for application in Terahertz (THz) frequency spectrum. This SWB MIMO antenna configuration consists of orthogonally placed four coplanar waveguide (CPW) fed half elliptical patch antennas with connected ground planes. Three types of fractal curves are suitably applied on this MIMO configuration to obtain enhanced impedance bandwidth and good isolation between antenna elements. The proposed design exhibits an impedance bandwidth ($S_{11}$ $\le$ −10 dB) from 0.72 THz to 10 THz (ratio impedance bandwidth 13.89:1) and an isolation more than 20 dB between all four antenna elements is obtained over the entire band of operation. Stable radiation characteristics with moderate amount of gain are also observed The other MIMO performance parameters like Envelop Correlation Coefficient (ECC), Diversity Gain (DG), Channel Capacity Loss (CCL) and Total Active Reflection Coefficient (TARC) are also within acceptable limit over the entire THz frequency of operation. The proposed design consists of more number of antenna elements with relatively smaller physical dimension compared to the existing SWB MIMO antenna designs available in literature in THz frequency range. Therefore, this proposed MIMO antenna design can be used for THz applications in future beyond the fifth generation (B5G) technology.