基于π型结构双折射超表面的设计与应用

Design and application of birefringent metasurface based on π-shape structure

为了实现结构简单、透射率高的双折射超表面,采用广义薄板跃迁条件分析了该超表面结构与其周围入射场、反射场和透射场的关系,并利用介质空间域的表面极化率、磁化率等描述了相应超表面的等效特性,设计出一种基于π型金属结构单元的双折射超表面。通过将具有梯度透射相位的7个单元按照顺序排列,形成具有对垂直入射x,y极化电磁波双折射性能的超表面。结果表明,在波束折射和偏振分束超表面中,损失均低于-8dB;λ/4波片中达到全透射;所设计的双折射超表面对垂直入射的电磁波具有高透射特性,并且能够分离x极化电磁波和y极化电磁波的波束,实现双折射。该研究结果对高性能超表面的设计与实现具有一定的指导意义。

In order to realize birefringent metasurface with simple structure and high transmittance,the generalized thin plate transition conditions was used to analyze the relationship between metasurface structure and incident field,reflection field and transmission field around it.Surface polarizability and magnetic susceptibility of dielectric space domain were utilized to describe the equivalent properties of the corresponding metasurfaces.A birefringent metasurface based onπ-shaped metal structure unit was designed.By arranging 7 elements with gradient transmission phase in sequence,a metasurface with birefringence of x-polarized,y-polarized electromagnetic waves was formed.The results show that,in beam refraction and polarization splitting metasurfaces,the loss is less than-8dB.Full transmission is achieved inλ/4 wave-plate.The designed birefringent metasurface has high transmission property to electromagnetic wave incident vertically.Beam separation of x-polarized electromagnetic wave and y-polarized electromagnetic wave can be realized.The birefringence is realized.The research results have certain guiding significance for the design and implementation of high performance metasurfaces.