基于线性偏振转换器的太赫兹波段超宽带成像系统设计

Design of Terahertz-band Ultra-broadband Imaging System Based on Linear Polarization Converter

基于偏振转换的物理过程,提出了一种由金属光栅、L型金属贴片和介质板组成的超宽带高效线性偏振转换器。利用有限元数值模拟软件CST对偏振转换特性进行了研究。数值结果表明,偏振转换器在0.5~1.8 THz工作,相对带宽达到113%,传输系数大于0.87,偏振转换率接近100%。利用Matlab建立了Fabry-Perot干涉模型,验证了理论分析结果与数值结果的一致性。通过改变该偏振转换器的结构参数,构造“1”“0”幅度编码超表面。该编码超表面在线极化太赫兹波入射下,实现了“IUTL”的空间成像功能。所设计的超表面对于入射波的极化方向不敏感,并展现出超宽带、高传输效率的特性,在无线通信领域具有潜在的应用价值。

Based on the physical process of polarization conversion,an ultra-broadband and efficient linear polarization converter composed of metal gratings,L-shaped metal patches and dielectric plates are proposed.The polarization conversion characteristics are studied using the finite element numerical simulation software CST.The numerical results show that the polarization converter operates at 0.5~1.8 THz with a relative bandwidth of 113%,transmission coefficient greater than 0.87,and polarization conversion rate close to 100%.Furthermore,a Fabry-Perot interference model is established by Matlab to verify the consistency between the theoretical analysis results and numerical results.By changing the structural parameters of the polarization converter,a“1”and“0”amplitude encoded metasurface is constructed.The encoded metasurface realizes the spatial imaging function of“IUTL”under the incidence of linearly polarized terahertz waves.The designed metasurface is insensitive to the polarization direction of the incident wave and exhibits features of ultra-broadband and high transmission efficiency.It has potential applications in the field of wireless communication.