基于多层结构的偏振不敏感超材料太赫兹宽带吸收器

Polarization-Insensitive Metamaterial Terahertz Broadband Absorber Based on Multilayer Structure

为了解决宽带吸收器结构设计复杂的问题,提出了一种结构简单、偏振不敏感、吸收性能优良的超材料太赫兹宽带吸收器。该吸收器采用对称结构设计,以金属层--介质层--金属层的三层架构为基础。其中,介质层中嵌入了两个不同尺寸的圆形金属片,从而形成多层结构。采用频域有限元法(Frequency Domain Finite Element Method,FEM)分析了该吸收器的宽带吸收率、偏振敏感性和入射角度等特性。仿真结果表明:该吸收器可以实现5.86~7 THz的宽带吸收,吸收带宽为1.14 THz,带宽内的吸收率在95%以上,且对于垂直入射的电磁波偏振并不敏感,在一定入射角度内依然保持宽带吸收。该吸收器结构设计简单且具有优良的性能,在太赫兹成像和电磁隐身等领域中具有重要的应用价值。

In order to solve the problem of complex design of broadband absorber,a polarization insensitive metamaterial THz broadband absorber with simple structure and excellent absorption performance is proposed.The absorber adopts symmetrical structure design,which is based on the three-layer structure of metal layer-medium layer-metal layer.Two circular metal sheets of different sizes are embedded in the medium layer to form a multilayer structure.Frequency domain finite element method(FEM)is used to analyze the broadband absorption rate,polarization sensitivity and incident angle of the absorber.The simulation results show that the absorber can achieve wide band absorption of 5.86~7 THz,and the absorption bandwidth is 1.14 THz.The absorption rate is more than 95%within the bandwidth,and it is not sensitive to the polarization of vertically incident electromagnetic wave.And it still maintains broadband absorption within a certain incidence angle.The absorber has a simple structure design and excellent performance,which has important application value in terahertz imaging and electromagnetic stealth fields.