Low Frequency Wireless Power Transfer for Biomedical Implants

Institute of Microengineering - Distinguished Lecture

Due to the covid-19 related restrictions currently in place, the lecture will be held remotely by zoom only.

Zoom Live Stream: https://epfl.zoom.us/j/975059431

Abstract: Biomedical implants hold the promise of dramatically improving our health and well-being by, for example, enabling us to pro-actively monitor health through real-time tracking of internal body chemistry (e.g. pH, glucose, lactate, tissue oxygen), treat diseases through targeted and tailored drug delivery, treat neural disorders through neural prostheses, etc.  Furthermore, advances in flexible integrated circuit technology and micro scale sensing can currently enable extremely small (< 1mm3), complex, biomedical implants.  However, systems of this size are almost never actually realized because the power system (e.g. a battery) is too large.  RF power transmission for implants has been widely investigated. However, for very small implants (~ mm3) RF power suffers from low achievable power density at the implant given safety constraints.
This talk will discuss two alternative methods for wirelessly delivering power to biomedical implants: acoustics and low frequency magnetic fields using magnetoelectric transducers. Acoustic power transmission exhibits high power density given its low attenuation in soft tissue and relatively less restrictive safety limitations. Its disadvantages are that acoustic power does not travel well through bone and the external transmitter requires intimate contact with skin. In this talk we will cover acoustic power transmission systems and demonstrate a novel glucose sensing mechanism that can be powered acoustically. Low frequency magnetic fields coupled to magnetoelectric transducers offer a promising alternative to both RF and acoustic power transmission. In this system, a standard coil is used as a transmitter, but the implantable receiver is made from magnetoelectric laminates (i.e. laminates of magnetostrictive and piezoelectric material). The magnetoelectric receivers have a much more favorable frequency/size relationship than standard RF receivers, enabling higher power density at lower frequencies that are safer for humans and have lower attenuation in tissue. In this talk I will discuss system and receiver design optimization for magnetoelectric based wireless power transfer systems. These systems are still early stage, and there is much room for innovation and improvement.

Bio: Shad Roundy is the director of the Integrated Self-Powered Sensing lab at the University of Utah which focuses on energy harvesting, wireless power transfer, and more generally applications of ubiquitous wireless sensing. Shad received his PhD in Mechanical Engineering from the University of California, Berkeley in 2003.  From there he moved to the Australian National University where he was a senior lecturer in the Systems Engineering Department.  He spent the next several years working with startup companies LV Sensors and EcoHarvester developing MEMS pressure sensors, accelerometers, gyroscopes, and energy harvesting devices.  In 2012, he re-entered academia joining the mechanical engineering faculty at the University of Utah.  Dr. Roundy is the recipient of the National Science Foundation CAREER Award, DoE Integrated Manufacturing Fellowship, the Intel Noyce Fellowship, and was named by MIT’s Technology Review as one of the world’s top 100 young innovators for 2004.

Note: The Seminar Series is eligible for ECTS credits in the EDMI doctoral program