基于石墨烯超材料的可调谐太赫兹滤波器

A tunable terahertz filter based on graphene metamaterial

  • 摘要: 超材料通过人工设计的微结构可获得天然材料所不具备的电磁响应,进而在太赫兹等特定频段实现高性能滤波。然而,一般基于金属材料结构的超材料滤波器,其结构固定后滤波特性无法改变。鉴于石墨烯具有费米能级可调的特性,将其引入超材料滤波器设计,构建了一种石墨烯超材料滤波器结构,探究几何结构参数和石墨烯费米能级对可调谐滤波器滤波特性的影响。仿真结果表明,超材料结构的线宽增加会导致透射曲线中谐振峰的中心频率由1.95 THz升至2.27 THz;结构的边长增加会导致谐振峰的中心频率由2.38 THz降至2.16 THz;石墨烯的费米能级增大会导致谐振峰的中心频率由2.08 THz增至2.19 THz。该超材料滤波器的滤波特性可以通过几何参数实现初始化设计,再通过外加电场等手段调节石墨烯费米能级实现动态调控。为太赫兹波段提供了一种新型滤波器设计方案,实现了非机械式动态调谐,也为智能太赫兹器件的开发提供了创新思路。

     

    Abstract: 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.

     

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