基于金属-绝缘体-金属光栅结构的功分器及分波器设计

摘要

设计了一种基于仿表面等离激元（Spoof surface plasmon polaritons，Spoof SPPs）的金属-绝缘体-金属（metal/insulator/metal，MIM）光栅结构的Y型功分器和分波器。MIM光栅结构由两块内侧加工有周期性凹槽的有限厚度金属板构成，工作于微波波段，采用单极子作为激励来激发光栅结构上的仿表面等离激元。其中功分器的两个输出分支采用凹槽深度相同的光栅结构，可以将从输入端来的电磁波平均分成两个部分，然后分别朝着两个输出分支传播；而分波器的两个输出分支则采用凹槽深度不同的光栅结构，可以使不同频率的电磁波朝着不同的分支传播。利用三维电磁仿真软件CST微波工作室（CSTmicro-wave studio）对该功分器和分波器进行仿真分析，加工出分波器实物并进行了实验测试，测试结果与仿真分析基本吻合，验证了方案的可行性。%A Y-shaped power divider and a Y-shaped frequency splitter,based on plasmonic MIM (metal/insulator/metal)grating structures,are proposed in this research.The plasmonic MIM grating structure is fabricated by use of two metal plates with finite thickness whose inner boundaries are carved with periodic grooves.It works at microwave frequency.A cylindrical wire is used to excite the spoof surface plasmon polaritons (SPPs)on the MIM gratings.The two output branches with the same groove depths of the powerdividerare applied toseparate theelectromagnetic (EM)waves into two equal partswhich propagate along the two out-put branches.The two output branches with different groove depths of the frequency splitter can be used to generate the EM waves at different frequencies which propagate along the different branches.In the experiments,CSTmicrowave studio,a 3DEM simulation software,is applied to simulate and analyze the designed power divider and frequency splitter;and a frequency splitter sampleisfabricated.The measurement results are consistent with the results of simulation,which verify the feasibility of the pro-posed structures.