Gao Zhou-Hao, Li Xin-Shuo, Mao Man, Sun Chen, Liu Feng-Xue, Zhang Le, Zhao Lei
JSNU SPBPU Institute of Engineering, Jiangsu Normal University, Xuzhou 221116, China.
School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China.
Micromachines (Basel). 2023 Aug 29;14(9):1687. doi: 10.3390/mi14091687.
An ultra-compact low-pass spoof surface plasmon polariton (SSPP) filter based on an interdigital structure (IS) is designed. Simulated dispersion curves show that adding the interdigital structure in an SSPP unit effectively reduces its asymptotic frequency compared with traditional and T-shaped SSPP geometries, and the unit dimensions can be conversely reduced. Based on that, three IS-based SSPP units are, respectively, designed with different maximum intrinsic frequencies and similar asymptotic frequencies to constitute the matching and waveguide sections of the proposed filter, and the unit number in the waveguide section is adjusted to improve the out-of-band suppression. Simulation results illustrate the efficient transmission in the 05.66 GHz passband, excellent out-of-band suppression (over 24 dB) in the 5.9512 GHz stopband and ultra-shape roll-off at 5.74 GHz of the proposed filter. Measurement results on a fabricated prototype validate the design, with a measured cut-off frequency of 5.53 GHz and an ultra-compact geometry of 0.5 × 0.16 .
设计了一种基于叉指结构（IS）的超紧凑低通类表面等离子体激元（SSPP）滤波器。模拟色散曲线表明，与传统和T形SSPP几何结构相比，在SSPP单元中添加叉指结构可有效降低其渐近频率，并且单元尺寸可以相应减小。基于此，分别设计了三个具有不同最大固有频率和相似渐近频率的基于IS的SSPP单元，以构成所提出滤波器的匹配和波导部分，并调整波导部分的单元数量以提高带外抑制。仿真结果表明，所提出的滤波器在05.66 GHz通带内具有高效传输，在5.9512 GHz阻带内具有出色的带外抑制（超过24 dB），在5.74 GHz处具有超陡滚降。对制作的原型进行的测量结果验证了该设计，测得的截止频率为5.53 GHz，几何尺寸超紧凑，为0.5×0.16 。
