提出一种基于超材料的由上下层格栅金属和中间层聚酰亚胺薄膜组成的太赫兹宽频反射器,可解决现有反射器遇到的反射率与反射带宽无法同时最优的问题。利用时域有限差分法对该反射器的反射性能进行研究和分析,通过优化金属层数、中间层聚酰亚胺薄膜厚度、格栅周期长度及格栅宽度等,确定了可以同时提高反射带宽和反射率的特征尺寸。结果表明:这种反射器在太赫兹频段具有优异的反射性能和较大的反射带宽,在0~4.0 THz工作频段内,其反射率在0.98以上的频段宽度可达2.04 THz。所提结构为太赫兹宽频通信技术的发展提供了一种高性能反射器件的设计方案。

In this paper, a metamaterial terahertz broadband reflector, which is composed of a middle layer of polyimide film sandwiched between upper and lower metal gratings, is proposed. This new design overcomes the incapability of existing reflectors to simultaneously optimize the reflectivity and reflection bandwidth. The reflection performance of the reflector was analyzed by the finite difference time domain method, and the number of metal layers, thickness of the polyimide film, length of the grating period, and grid width were optimized for achieving wide-band reflection and high reflectivity. Results show that this reflector has excellent reflection performance and large reflection bandwidth in the terahertz frequency band. In the 0-4.0-THz working band, the bandwidth with reflectivity above 0.98 can reach 2.04 THz. The proposed method provides a design scheme for high-performance reflectors for the development of terahertz broadband communication technology.