Ultrathin flexible coils for wireless power and data link in biomedical sensors

This paper presents a study on thin flexible coils for wireless power and data link in biomedical sensors. The coils used in this study are built with 9-μm-thick aluminum (Al) and 12-μm-thick blue-colored polythylene terephthalate (PET), which is called Al-on-PET bilayer flexible coils. A wireless power system is designed to test the coils under different operation conditions, in which the coils are attached to different parts of human body. The measurement results show that the coils maintain a relative good quality factor in a frequency range from 5.62 MHz to 6.5 MHz. The open-loop transmit efficiency of the wireless power system attains 80.63% when the ultrathin coil is attached to arm.