Full Modeling, Loss Reduction, and Mutual Coupling Control of Spoof Surface Plasmon-Based Meander Slow Wave Transmission Lines

The full models of meander spoof surface plasmon (SSP) cells are presented for the design of slow wave transmission lines (SW-TLs) with the minimum loss and controllable mutual coupling (MC). In addition to the modeling of dispersion curve and characteristic impedance, the proposed circuit model based on geometrical parameters calculates the ohmic loss of the SW-TLs composed of meander SSP cells. Being verified with the full-wave analysis, the model provides a clear understanding of the mechanism of the SSP-based SW-TLs and a new way to design with other circuits at a system level. The model is applied to minimize the ohmic loss in the meander SW-TLs up to at least 10 dB per 10 wavelengths lower than that of conventional TLs. The MC of the SW-TLs can be controlled either up to three orders of magnitude lower or one order of magnitude higher than that of the conventional TLs. This paper proposes methods to decrease the ohmic loss of single-layered meander SW-TLs and also controls MC between them. The proposed methods open new avenues for complex and compact circuit designs.