Far-Field Wireless Power Beaming to Mobile Receivers Using Distributed, Coherent Phased Arrays: A Review of the Critical Components of a Distributed Wireless Power Beaming System

Over the last few decades, far-field RF-based wireless power beaming (WPB) has been a topic of interest for the microwave and the antenna engineering communities alike, and there have been quite a few articles published in the IEEE Microwave Magazine related to this topic in the last 20 years, which is evidence of the high interest of the community. This interest is likely due to the dire need for such a system for applications, ranging from biomedicine to drone charging [1] , [2] , [3] , [4] , [5] . While these prior published articles have been a great resource for new researchers in this area, who can gather tons of resources and information by reading these articles, we (the authors of this article) realized a comprehensive review is still lacking, where the challenges and opportunities regarding WPB to dynamically and rapidly moving targets [e.g., unmanned aerial vehicles (UAVs)] using multiple, distributed transmitters (TXs) are summarized and discussed in detail. We envision that the next generation of wireless power transfer (WPT) networks will be scalable, safe, and efficient, enabling a robust RF energy web that can be deployed using mobile autonomous platforms, such as unmanned aerial systems, as depicted in Figure 1 .