Dielectric resonator-based tunable circularly polarized THz MIMO antenna with split ring resonator for isolation control method
Harshmani Yadav, Rajesh Yadav, Yagyadatta Goswami, Manish Rai, Anup Kumar
Abstract
Abstract An advanced isolation control technique is proposed for a terahertz (THz) multi-input multi-output (MIMO) antenna, significantly enhancing port-to-port isolation. This approach utilizes a silicon-based dielectric resonator antenna for high-performance tunable THz MIMO system. The design follows a structured evolutionary process, beginning with a dual-feed (DF) configuration without a dielectric resonator as the baseline model. Enhancements were introduced by incorporating a graphene metal coating, improving tunability and isolation. Further refinements involved integrating a split square ring resonator without an RDRA, enhancing isolation and polarization characteristics. The design was then optimized by introducing a metal-coated RDRA, improving gain, radiation efficiency, and circular polarization purity. Additionally, a complementary split ring resonator-loaded circularly polarized DF structure was incorporated for further performance enhancement. The proposed MIMO antenna achieves 25.5 dB isolation at 7.2 THz without a metal coating. By applying a graphene coating, isolation increases to 49 dB at 7.42 THz, using graphene’s tunable conductivity under an external DC bias for dynamic reconfiguration. The antenna exhibits excellent pattern diversity, with an envelope correlation coefficient below 0.003 and a diversity gain of 9.94 dB. Further isolation improvement is achieved by integrating a split-ring resonator on the dielectric material, enhancing isolation up to 59 dB. These advancements make the proposed antenna highly suitable for THz applications.