A metasurface integrated self-decoupled multiport tunable antenna for THz applications

Abstract A four port multiple-input multiple-output (MIMO) antenna is initially designed on silicon dioxide (quartz) substrate by arranging the antenna elements in an orthogonal configuration by using self-decoupling mechanism. Mean effective gain lower than 0.5 and radiation efficiency greater than 95% are obtained. Characteristic mode analysis of the proposed MIMO antenna has been performed using finite integration technique to validate the resonant modes. Further, a dual band self-multiplexing MIMO antenna has been constructed by loading each antenna element with a graphene constituted stub. Graphene loading in the antenna elements is done to introduce tunability in the MIMO operation in two frequency bands. The dual resonance frequencies range from 4.3–4.6 THz and 5.2–5.6 THz while the chemical potential is varied from 0.1 eV to 0.9 eV. The diversity performance of the MIMO antenna with and without graphene loading have been analyzed through numerical simulations. Envelope correlation coefficient lower than 0.0002 and diversity gain of 10 dB have been obtained. By biasing each of the antenna elements with different voltages, quadruplexing mechanism can be performed since each antenna resonates at a different frequency. Finally, a metasurface is designed on silicon dioxide (quartz) substrate to function as a reflective surface from 3.75–6.42 THz covering the resonance band of the tunable MIMO antenna for enhancing its gain to 14 dBi.