Electrically tunable triple-narrowband terahertz filter using a graphene-embedded metasurface

Terahertz (THz) filters have significant applications in high-speed communications, spectral analysis, and imaging. This work proposed an electrically tunable triple-narrowband transmissive THz filter based on a graphene-embedded metasurface. The filter adopts a triple resonator structure, where three graphene-embedded split-ring resonators are asymmetrically staggered along the THz wave propagation direction (z axis). By integrating a multi-channel independent gate voltage system to control the conductivity of graphene strips, it enables precise manipulation of the filter’s electromagnetic response. Simulation results show that the filter exhibits three transmission peaks at 0.52, 0.74, and 1.11 THz, with a maximum transmittance modulation depth of 82.4%. Through the three-channel voltage combination, eight transmission states can be programmatically generated to realize the independent switching and amplitude control of the triple bands. This filter provides novel, to the best of our knowledge, solutions for multi-channel THz communication and reconfigurable spectral analysis.