Design Of A Phased Array-based Dual Mode One-to-many Microwave Wireless Energy Transmission System

In the era of Internet of Things,a large number of low-power communication devices are deployed wirelessly,and the ways to supply power for these devices gradually shift from traditional battery power to wireless power.At present,the mainstream method available for powering multiple targets over long distances is electromagnetic energy radiation based on radio frequency microwave frequencies.In this thesis,the phased array technology was introduced and implemented to a wireless energy transmission system for multiple targets.By using beam forming,a focused energy supply was realized,which is an effective and convenient way for charging mobile devices wirelessly,and has broad application prospects and meaningful.The main research topics are listed as follows.(1)The phase and amplitude controller for this system were designed based on the principals of the phased array technology.Those controllers and their links were implemented modularized for lower cost,easy replacement,and better agility for controlling the emitted beam.(2)To comply with the one-to-many power transmission scheme,of the system,a high gain quasi-Yagi antenna was designed,with single split-ring resonator structure to enhance its gain performance,and also the half power beam width was optimized for better performance in the focused power transmission process.(3)To optimize the power transmission efficiency in a multi-node scenario,the control strategies of time-division total array transmission mode and sub-array divided mode were studied.By applying both the k-means clustering algorithm and the greedy algorithm to a pre-processed training dataset,the optimized control strategy can be obtained automatically for different targets clustering cases,and the correctness of this algorithm was tested with software simulation.(4)After testing it was observed that the proposed system can supply power to multiple targets at a distance of 3m,spread within ±40° along the main axis of the transmitting antenna array.Comparing these different control strategies,it was observed that the strategy given by the proposed algorithm has a higher overall transmitted power to the targets.For two-targets,the total received power was 13.16 d Bm·s,which is8.85 d Bm·s higher than without the algorithm mode,for three-targets scenario,15.35 d Bm·s was received by the targets,which is 12.72 d Bm·s higher.The experiment shows that this system is capable to power the low-power sensor multi-node.