Towards Batteryless Internet of Things (IoT) Sensing Systems: Far-Field Wireless Power Transfer and Harmonic Backscattering

One essential foundation of IoT technology is the development of numerous interrelated IoT sensors distributed extensively in our environment. Conventional batteries/cords-based powering solutions are certainly not an acceptable long-term and sustainable solution, considering the incurred cost, feasibility, and most of all, environmental impact. A promising and “green” powering alternative solution for IoT sensors is recycling omnipresent ambient RF energy, which is actually dissipated in free space if not consumed by end-users immediately. The concept of harnessing wireless energy for powering IoT sensors requiring a higher power supply is also feasible through the dedicated wireless power delivery from specialized power base-stations, which can be an effective supplement. To realize the RF power scavenging, this talk focuses on two mainstream techniques: far-field wireless power transfer (WPT) and harmonic backscattering. As a preliminary research step and a feasibility study, a survey of ambient RF energy density in the core areas of Montreal is summarized first. Then, design and optimization techniques regarding low-power far-field rectifiers and fully passive harmonic transponders are presented.