Washable Stitched Transmission Line for Wearable Applications

In this paper, the washability of a stitched transmission line is been studied. The aim is to determine the deterioration of the frequency dependence of the scattering parameters of the stitched transmission line after subjecting it to washing cycles using a domestic washing machine. The DC resistance of the stitched transmission line was measured before and after wash with results indicating an increase in the DC resistance from 16.9 Ω to 22.8 Ω after washing the stitched transmission line. The increase in DC resistance is due to the decrease in conductive path of the stitched transmission line as a result of the abrasion impacts in the washing machine leading to increased number of fissures and defects on the stitched transmission line. The propagation characteristics of the stitched transmission line were investigated using CST Microwave Studio Suite® and measurements on the stitched transmission line before and after wash was carried out using an Anritsu MS46524A 7GHz Network Analyser for a frequency range of 0.04 to 4 GHz, with results demonstrating that the stitched transmission line will make a good candidate for wearable applications.