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

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.

Speaker: Joshua Smith, Univ. of Washington