Analysis of MR-WPT using planar textile resonators for wearable applications

This study presents the design and analysis of a magnetic resonant coupling wireless power transfer (MR-WPT) system that employs planar textile resonators. To reduce the size of the system for wearable applications, the transmitter and receiver are designed and fabricated on a flat plane of fabric. A proposed symmetric four-resonator MR-WPT system is used for verifying the electromagnetic property of the textile substrates. Two textile substrates: polyester and cotton fibre are investigated to determine their impact on the transfer efficiency. Experiments show that the transfer efficiency is considerably higher with the polyester substrate than with the cotton substrate. In addition, copper tape and silver paste are employed for the resonator fabrication because of their flexibility. The measured results show that the copper tape has a significantly higher transfer efficiency than the silver paste because of its high conductivity. At a transfer distance of 5 cm, the maximum transfer efficiency is 50% with the polyester substrate and the copper tape resonator. Furthermore, the width of the coil-pattern is varied to determine its impact on the resonant frequency and the transfer efficiency of the MR-WPT system. This research confirms the feasibility of using flexible MR-WPT for wearable applications.