Pressure and humidity detector based on textile integrated waveguide

In the paper, a pressure sensor and a humidity sensor are designed as supplementary components of a textile integrated waveguide (TIW) based on an artificial magnetic conductor (AMC) consisting of hexagonal elements. Thanks to AMC, sewing of electrically conductive side walls can be eliminated. Since operating in the stop-band of TIW, the sensors do not influence transmission parameters of TIW, and provide an additional functionality. For fabrication, a three-dimensional knitted fabric was used as a substrate and conductive surfaces were created from a self-adhesive copper foil. The sensors were simulated, manufactured and measured in the frequency range from 10 GHz to 12 GHz with a reasonable agreement. Since the designed components are sensitive on manufacturing tolerances, a higher measured insertion loss in TIW can be observed compared to simulations. Nevertheless, the insertion loss can be reduced when manufacturing accuracy is improved.