Integrated Electromagnetic Wireless Power Harvesting System for mm-size Biomedical Implants
Master of Science
Rising demand for continuous monitoring of human body and health care devices in recent years has resulted in the development of implantable biopotential sensors. Infection risks and mobility concerns constrain the implanted sensors to operate without any transcutaneous wire connection which raises serious challenges for powering and data telemetry. Lack of enough information on many physiological processes such as human speech production dynamics has hindered research on bases of the processes and it mainly stems from available measurement systems limitations. In this work, we use electromagnetic waves in GHz frequency range to transfer the required power to the implanted system. The optimum frequency for wireless power transfer is studied as a function of transmitting and receiving antennas as well as the dispersive characteristics of the biological tissues. We present two types of power harvesting platform with on-chip antennas that can be integrated on a silicon chip. The second power harvesting system is designed to have a long-range operating range and harvests electrical energy from a far-field electromagnetic source and can be exploited to power up ultra-low power biomedical implants. The second system is designed to increase the functionality of a complex implant such as a neural recording system. While maintaining the losses in biological tissues below Specific Absorption Rate (SAR) limit, the harvesting system can provide milliwatts of power the operation of a high performance fully integrated biomedical implant.