Microstrip transmission line model‐fitting approach for characterization of textile materials as dielectrics and conductors for wearable electronics

Characterization of unconventional materials is essential in the field of microwave engineering. In this study, we present a method for the microwave characterization of conductive and nonconductive textile materials. Our approach is based on fitting the material parameters of a numerical microstrip transmission line model so that the simulated signal transmission properties match with the data we measure from implemented test lines. Unlike many conventional test structures, such as cavity resonators and waveguides, microstrip lines can be readily manufactured in textile technology with rather relaxed tolerances in the fabrication process. In addition, our method provides estimates for all three key material parameters: frequency‐dependent relative permittivity and loss tangent of the nonconductive line substrate and the bulk conductivity of the strip conductor. For validation, we have characterized conventional microwave laminates and compared the data with the datasheets and literature and used our parameter estimates for the textile materials to optimize fully textile‐based low‐pass filters. Overall, the results confirm the applicability of our method for microwave engineering with textile materials.