Integration of resonant coil and antenna for wireless power transfer and data telemetry

In this study, the Rx resonant coil for the wireless power transfer (WPT) operating at 13.56 MHz is integrated with the antenna for the medical communications service (MICS) band communications. They shares the PCB area of a narrow bar-type shape; the coil has outer current path of the substrate and the meandered planar inverted-F antenna (PIFA) is designed to be located inside the coil. To verify the potentials of the proposed structure, a prototype is fabricated and tested in air and in vitro. The power transfer efficiency (PTE) of about 20% at 15 mm distance and antenna gain of roughly -40 dBi are obtained.