Phase-Accurate Analytical Transmission Line Model and for a 1–50 GHz Millimeter-Wave Textile-Based Wearable Goubau Single Wire Transmission Line (SWTL)

Goubau-Sommerfeld Single Wire Transmission Lines (SWTLs) are a feasible approach for low-loss high-speed transmission. However, the long length of an SWTL makes full-wave electromagnetic simulations too computationally intensive. In this paper, a transmission line model is proposed for a state-of-the-art textile-based wearable broadband millimeter-wave SWTL, which represents the first broadband closed-form analytical model for a wearable surface wave transmission line. The inductance and capacitance are calculated per unit length using closed-form formulas and used to construct a simple SWTL equivalent circuit based on the lossy transmission line model. The analytically calculated phase exhibits under 7% error compared to vector network analyzer (VNA) measurements from 2 to 50 GHz. The VNA measurements are then used to fit the loss terms in the model leading to a good agreement between calculations, full-wave simulations, and experiments. It is anticipated that the developed model and low-cost mmWave SWTL will empower future integration of low-loss SWTLs in different applications without the need for complex numerical simulations.