基于新型蝶形单元结构人工表面等离子体激元低通陷波滤波器的设计

为降低滤波器的插入损耗以及实现滤波器的小型化，该文提出一种新型具有陷波功能的人工表面等离子体激元(SSPPs)低通滤波器，该滤波器主要由新型蝶形单元结构、过渡结构以及用于实现陷波功能的叉指电容环路谐振器(IDCLLR)结构组成。新型蝶形单元结构是由一个椭圆形贴片向左右方向旋转30°构成，经过镂空处理后可以显著降低插入损耗，相比传统的矩形和椭圆形结构具有更好的色散特性，大大提高了滤波器的带内的平坦度和带外抑制能力。该文对矩形、椭圆形、梯形以及新型蝶形等不同单元结构的色散曲线进行了分析，并仿真分析了滤波器的S₂₁和S₁₁曲线，验证了新型蝶形单元结构在色散特性、插入损耗、低截止频率和带外抑制方面所具有的优势。最后，对该滤波器进行了加工和测试，测试结果表明，该滤波器仿真结果和测试结果吻合较好，表现出较好的带外抑制和带内平坦度，可以实现对特定干扰频段陷波抑制。滤波器尺寸为0.98λ₀×0.17λ₀。该人工表面等离子体激元滤波器从设计新型单元结构的角度出发，实现了良好性能的同时，实现了滤波器的小型化。

Design of Spoof Surface Plasmon Polaritons Low Pass Notch Filter Based on Novel bow-tie cell Structure

To reduce the insertion loss of the filter and achieve filter miniaturization, a novel Spoof Surface Plasmon Polaritons (SSPPs) excitonic low-pass filter with a notched band is proposed, which consists mainly of novel bow-tie cells structure, transition structures, and InterDigital Capacitance Loaded Loop Resonators (IDCLLR) structures used for accomplishing the notch function. The novel bow-tie cell structure is composed of an elliptical patch rotated 30° to the left and right directions, which can significantly reduce insertion loss after hollowing out. Compared with the traditional rectangular and elliptical structure, novel bow-tie structure has better dispersion characteristics, which improves greatly the filter's in-band flatness and out-of-band rejection capability. In addition, the dispersion curves of different cell structures such as rectangles, ellipses, trapezoids and novel bow-tie are analyzed, and the S₂₁ and S₁₁ curves of filters are simulated. The results show that the novel bow-tie unit structure has advantages in dispersion characteristics, insertion loss, low cut-off frequency and out-of-band suppression. Finally, the filter is processed and tested, and the test results show that the filter simulation results and test results match well, have good out-of-band rejection and in-band flatness, which can achieve notch suppression for specific interference bands. The size of the filter is 0.98λ₀×0.17λ₀. From the point of view of a new element structure is designed, this SSPPs filter achieves good performance and miniaturization.