Experimental study on resonant wireless power transfer to mechanically flexible receiver for wearable electronics

The technological innovation in flexible electronics has been remarkable during the last few years. On the other hand, wireless power transfer (WPT) appears as one of the emerging area of research in the last decade. This paper presents an experimental study on a resonant WPT system having a receiver coil fabricated on flexible substrate. Two different cases of bending applied to flexible coil are investigated. We reveal that up to certain limit of bending power transfer efficiency is not affected, and after that there is a significant reduction in efficiency. This reduction is attributed to the change of resonant frequency. In addition, the reduced effective area of receiver coil causes decrease of the magnetic flux captured from transmitter when the flexible receiver is bent.