An embroidered spoof surface plasmon polariton transmission line for wearable wireless body area networks based on Minkowski fractal structure

Abstract This paper proposes an embroidered SSPP TL (spoof surface plasmon polariton transmission line) based on a Minkowski fractal geometric structure. Theoretical analysis indicates that transmission lines with Minkowski fractal structures exhibit lower dispersion cutoff frequencies compared to conventional transmission lines. Additionally, the dispersion characteristics of fractal transmission lines can be adjusted by varying the indentation depth and iteration count of the fractal design. Based on this concept, both a conventional transmission line and a fractal transmission line were fabricated. Test results show that the dispersion cutoff frequency of the fractal transmission line is 31 % lower than that of a conventional transmission line of the same width. Measurements conducted on different body parts, combined with SAR (Specific Absorption Rate) analysis, further demonstrate that the proposed transmission line can be safely and efficiently applied in human-body wearable systems.