A tunable terahertz filter based on graphene metamaterial

Metamaterials, featuring artificially designed microstructures, can achieve electromagnetic responses unattainable by natural materials, enabling high-performance filtering in specific frequency bands such as the terahertz (THz) band. However, conventional metamaterial filters based on metallic structures have a significant limitation: their filtering properties are unchangeable once the structure is fixed. Leveraging the tunable Fermi level of graphene, a graphene metamaterial filter structure was designed and investigated to explore the influence of geometric parameters and graphene Fermi level on its tunable filtering properties. Simulation results show that increasing the line width of the metamaterial structure could raise the center frequency of the resonant peak in the transmission spectrum from 1.95 THz to 2.27 THz, while increasing the side length could lower it from 2.38 THz to 2.16 THz. Elevating the Fermi level of graphene shifted the center frequency of the resonant peak from 2.08 THz to 2.19 THz. The filter characteristics could be initially designed through geometric parameters and then dynamically adjusted by modifying the graphene Fermi level via external means such as an electric field.This paper provides a novel tunable filter design for terahertz band, realizes non-mechanical dynamic tuning of the filter, and offer an innovative approach for developing smart terahertz devices.