Improved Reconfigurable Terahertz Microstrip Antenna for Present and Future Wireless Communication Systems

This paper presents the design and modelling of a frequency-reconfigurable multiband terahertz (THz) microstrip patch antenna targeted at present and future wireless communication front ends. The antenna is realized on a quartz substrate (εr = 3.82) with a thickness of 80 µm, using a slot-loaded rectangular patch topology with switchable conductive bridge elements based on VO₂ and graphene to enable state-controlled resonance tuning. Using Maxwell scale invariance and a MATLAB-based simulation workflow, three switching states are obtained with resonances at approximately 0.30 THz (State A), 0.60 THz (State B), and 0.90 THz (State C). The simulated impedance response satisfies the −10 dB matching criterion in all states, with minimum S₁₁ values of about −17 dB, −25 dB, and −15 to −16 dB, respectively. The corresponding −10 dB impedance bandwidths are 5.5 GHz (1.83%) at 0.30 THz, 9.6 GHz (1.60%) at 0.60 THz, and 10.0 GHz (1.11%) at 0.90 THz, with VSWR < 2 around each resonance. Radiation remains broadside and stable across states, with peak realized gain between 4.8–5.5 dBi and radiation efficiency peaking at approximately 39–53% depending on the operating band. Overall, the results verify that the proposed VO₂/graphene-enabled structure delivers clear, switch-driven multiband operation in the THz regime, supporting candidate applications in 6G/THz links and high-data-rate short-range THz systems.