Improving the isolation of a tunable terahertz multi-input-multi-output dielectric resonator antenna using graphene coating

Abstract

A technique is developed for enhancing the isolation between the ports of a terahertz (THz) dielectric resonator (DR) antenna (DRA) with two ports and single radiator. A two-port DRA provides the isolation of 6.88 dB which is further enhanced to 16.78 dB by inserting a circular slot in the ground plane of this antenna structure. The sidewalls of the DR at opposite to the source ends are then coated with the graphene material which enhances the value of isolation between the ports up to 25.05 dB. The coating of top surface of DR with graphene material enhances the isolation up to 35.10 dB. Coating of graphene material at all the open surfaces of the DR can enhance the isolation up to 63.06 dB. The frequency response of antenna can be tuned by applying the electrostatic field on the graphene coating at top surface of the DR. Moreover, the multi-input-multi-output performance parameters like envelope correlation coefficient and diversity gain remains less than 0.06 and 9.8 in the passband. The orthogonal feed arrangement used in the antenna structure can provide the polarization diversity.