This paper reveals a relation between the cut-off frequency and the simplified equivalent circuit of a spoof surface plasmon polariton (SSPP). An SSPP transmission line (TL) with low upper cut-off frequency is proposed based on the relation. In this SSPP-TL, a double-layer interdigital strip is constructed to increase the capacitance in the simplified equivalent circuit model, and in turn the cut-off frequency is decreased. The proposed SSPP-TL features an upper cut-off frequency of only 2.75GHz, which indicates that the proposed relation is instructive to design the geometry of an SSPP with low cut-off frequency.

中文翻译：

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表面等离子体极化子截止频率与等效电路的关系及其应用

本文揭示了截止频率与表面等离子体激元 (SSPP) 的简化等效电路之间的关系。基于该关系，提出了一种具有低上截止频率的SSPP传输线（TL）。在该SSPP-TL中，在简化的等效电路模型中构造了双层叉指带以增加电容，进而降低截止频率。所提出的 SSPP-TL 的上限截止频率仅为 2.75GHz，这表明所提出的关系对于设计具有低截止频率的 SSPP 的几何结构具有指导意义。