Stanford EE Computer Systems Colloquium

4:15PM, Wednesday, June 5, 2013
Skilling Auditorium, Stanford Campus

Wireless Power Transfer and RF Energy Harvesting: New Options for System Designers

Joshua R Smith
Sensor Systems Research Group, University of Washington
About the talk:

Wireless power is a capability that could change the design of systems such as implanted medical devices, smart structures, and consumer electronics. From Eniac to today, the energy efficiency of computing has improved by a factor of one trillion; this energy scaling trend is one of the key enablers for wireless power today. The talk will describe WISP, WARP, ABC, WREL, and FREED, systems that Smith's lab has developed in the course of exploring the space of wireless power techniques. WISP (Wireless Identification and Sensing Platform) is a platform for sensing and computing that is powered and read by standards-compliant UHF RFID readers. It has been used by researchers around the world for both "perpetual sensing" and RFID security research. The WARP (Wireless Ambient Radio Power) system is able to operate low power sensor nodes using energy harvested from broadcast TV or cell phone signals. ABC (Ambient Backscatter Communication, developed with Shyam Gollakota) combines ideas from WISP and WARP: like WARP, ABC sensor nodes are powered by ambient RF signals; like WISP, they communicate by reflecting preexisting RF signals, rather than generating their own. WISP, WARP, and ABC operate in the far field and have power budgets of tens of microwatts. WREL (Wireless Resonant Energy Link) and FREED (Free-range Resonant Electrical Energy Delivery, developed with Dr. Pramod Bonde of Yale School of Medicine) operate in the near field and provide tens of watts. The FREED system powers Left Ventricular Assist Devices (LVADs), implanted heart pumps that today require a transcutaneous power cable. The talk concludes with reflections on changes to the design space enabled by these capabilities, and discussion of future directions for RF-powered sensor and actuator systems.


Download the slides for this presentation in PDF format. (12 MB)

About the speaker:

[speaker photo] Joshua R. Smith is an Associate Professor in the departments of Computer Science and Engineering and Electrical Engineering at the University of Washington, Seattle, where he leads the Sensor Systems research group. He is interested in all aspects of sensor systems: developing novel sensors, powering them wirelessly, communicating with them, and using them in applications such as biomedical electronics, robotics, and ubiquitous computing. He the thrust leader for Communications and Interface in the NSF Engineering Research Center (ERC) for Sensorimotor Neural Engineering, and the theme leader for low power sensing and communication in the Intel Science and Technology Center for Pervasive Computing. He co-invented an electric field sensing system for suppressing unsafe airbag firing that is included in every Honda car. He is the editor of a book entitled Wirelessly powered sensor systems and computational RFID (Springer, 2013) that includes his work in this area as well as related work by other researchers. He received B.A. degrees in computer science and philosophy from Williams College, the M.A. degree in physics from Cambridge University, and the Ph.D. and S.M. degrees from the MIT Media Lab.

Contact information:

Joshua R. Smith
Associate Professor, CS and EE
University of Washington