Sub-1 GHz far-field powering of implantable medical devices: Design and safety considerations

Design and safety considerations for the development of wirelessly powered medical implants are discussed. Among others, we investigate the wireless transmission of adequate amount of power to the implanted device to ensure a reliable and long-term operation, and patient safety due to power absorption in biological tissues. Specifically, the power link performance between implantable and external dipole antennas in the sub-1GHz ISM (433.1-434.8, 868.0-868.6 and 902.8-928.0 MHz) frequency bands is evaluated in a generic level. Safety performance issues are, also, discussed. Finally, a radiofrequency energy harvesting system is developed with regard to the calculated wireless power link response.