Our life is becoming more convenient, efficient, and intelligent with the aid of fast-evolving wireless technologies, which require a massive deployment of interconnected but geographically scattered wireless sensing and communication devices. Conventional batteries/cords-based powering solutions will not sustain their extensive deployment, considering incurred cost, feasibility, and most of all, environmental impact. Therefore, a transformative powering solution for such large-scale and geographically scattered wireless devices becomes particularly important in supporting the widespread implementation while mitigating the environmental burden. In this talk, I will introduce our research on efficiently harnessing and recycling microwave energy to power wireless sensing and communications. First, I will present a city-wide RF survey in Montreal to fully understand how much ambient RF energy is available in our environment, an essential reference for designing recycling circuits that can work in the real world. Next, I will discuss our systematic analysis and understanding of far-field wireless power harvesting, enabling us to identify effective ways to enhance harvesting efficiency. Then, I will describe our advances in harmonic backscattering communication in the sub-6 GHz and millimeter-wave bands, including architecture improvement, accurate nonlinear analysis, and detection range enhancement. Finally, I will conclude this talk with my outlook on emerging opportunities for battery-free wireless sensing and communications. Co-sponsored by: IEEE Student Branch of Polytechnique Montreal Speaker(s): Dr. Xiaoqiang Gu, Room: L-2710, Bldg: Polytechnique University, 2500 Polytechnique Montreal Road (Quebec), Pavilion Lassonde , Montreal, Quebec, Canada, H3T 1J4