Research On Rf Energy Harvesting System Based On Artificial Magnetic Conductor

With the rapid development of the Internet of Things technology,smart machines and other devices can be connected to the Internet and become part of our information network.The development of the Internet of Things will change the way we monitor health,the environment,and infrastructure,and improve the operating efficiency,performance,and service quality of equipment.In many cases,these devices will be portable and wireless and will need to be powered by batteries,but the battery devices currently have a limited life and require periodic replacement.With the expansion of the Internet of Things and the increased demand for longer-term operation of the Internet of Things equipment,the number of battery devices that need to be replaced will become huge,which will cause a larger price.In order to solve this challenge,and at the same time overcome the traditional wind,solar and other energy harvesting methods are limited by time,space,weather and other factors,radio frequency energy harvesting solutions have been extensively studied.The antenna plays an important role in the radio frequency energy harvesting system,and the sensitivity and receiving range of the antenna have an important impact on the system's operating efficiency.This thesis introduces a two-layer compact Artificial Magnetic Conductor(AMC)structure as the antenna reflector of the radio frequency energy harvesting system to improve the receiving sensitivity of the antenna.In order to enable the receiving system to harvest radio frequency energy in the environment,a broadband low-power rectifier circuit is designed to harvest the radio frequency energy in the environment.The work of the thesis consists of the following parts:(1)According to the basic theory of artificial magnetic conductor(AMC)structure,the structure characteristics of single-layer and double-layer AMC are analyzed and studied.Then,the double-layer AMC structure is compared with the single-layer AMC structure,and it is concluded that the double-layer AMC structure has more compact structural characteristics.(2)A dual-layer AMC structure is used for the antenna design of the radio frequency energy harvesting system.A high-gain,low-profile antenna with a dual-layer AMC structure that operates at 2.4 GHz is designed.At the same time,in order to further improve thereceiving range of the antenna,a broadband circularly polarized high-sensitivity receiving antenna based on a double-layer AMC structure operating at 1.67-2.59 GHz was designed.(3)In order to convert the radio frequency energy collected by the receiving antenna into DC energy more,a low-power broadband rectifier circuit operating at 1.68-2.42 GHz is designed to generate a new resonant frequency point by introducing a resonant inductor.Coupling the natural resonance frequency point of the rectifier circuit and the resonance frequency point generated by the resonance inductor with the resonance frequency point of the matching circuit to achieve a broadband low-power rectification circuit.(4)A radio frequency energy receiving system was established,and the directional reception performance of the system and the environmental radio frequency energy harvesting performance were tested and analyzed to realize the power supply of the receiving system under low power conditions.