Design and Implementation of Wireless Low-Power Transfer for Medical Implant Devices

Abstract

Wireless power transfer (WPT) in medical implanted devices (MIDs) has received significant interest from both academic and the medical industry. These systems have suffered from battery-life that must be charged or replaced. Also, some implant devices are large, leading them to be uncomfortable. In addition, the device may interact with internal tissues, which may lead to reactions that affect the patient. This paper aims to produce a small MID operated by WPT to transmit vital signs (i.e., temperature) to an external station to ensure that the device does not affect the patient’s body. The proposed system used a flat spiral coil as a transmitter and a multi-layer copper wire coil as the receiver coil. The transmitter circuit was implanted inside a rabbit’s body. The temperature of the rabbit was sent using the nRF24L01 transceiver to the external monitoring station. The system reached an efficiency and power of 23.37% and 1.98 W respectively on 50 Ω load resistors. The proposed system was acceptable due to the small size of the coil, which provides a sufficient reception at a distance of 3 cm, exceeding the required power to operate the MID (i.e., 73 mW) and send data correctly.