一种单面双L型异向介质的设计及分析

Analysis and design of single double L metamaterial structure

针对目前已有的异向介质带宽窄,结构复杂的缺点,设计了一种工作在Ku波段的单面双L型异向介质结构。通过采用电磁仿真方法,建立平面电磁波垂直入射异向介质平板的模型,并提取其传输和反射数据;借助MATLAB工具,根据NRW（Niconlson-Ross-Weir）方法从中提取出该新型结构的等效介电常数和等效磁导率。仿真结果表明,这种单面双＂L＂型的结构在频段为14.2~15.9 GHz的等效介电常数与等效磁导率同时为负,其有效绝对带宽1.9 GHz;在11~17 GHz频段内的有效相对带宽为31.7%。因为这种异向介质结构在特定工作频率下电磁参数同时为负值,并且通过计算频率为15 GHz时的电磁波的相速为-2×10^7m/s,验证了该异向介质的结构具有后向波特性。这种结构具有便于制造及可控两大优势,具有很大的应用前景。

In allusion to the shortcomings of existing metamaterials, which have the belt width or complicated structure, a novel single double-L metamaterial structure is proposed in the Ku spectrum.By using the electromagnetic simulation method,electromagnetic wave vertical incidence to the metamaterial slab model is set up and the transmission and reflection data are extracted.According to the NRW method, the effective permittivity and effective permeability can beacquired with the aid of MATLAB tool.The simulation results show that the equivalent dielectric constant and the equivalent magnetic permeability are both negative in 14.2~15.9 GHz. Its effective absolute bandwidth is 1.9 GHz and its effective relative bandwidth is 31.7%.It is proved that the structure of this metamaterial has the back-wave property on account of the equivalent dielectric constant and the equivalent magnetic permeability are both negative of and the calculation for 15 GHz frequency electromagnetic wave phase velocity is-2×10^7m/s. This structure has the great advantages of easy manufacture and controllable in applications.