Research On Design Technology Of Microwave Rectenna Array Based On Metasurface

Microwave wireless energy transmission technology is a long-distance,high-power wireless energy transmission technology.It has a wide range of application prospects and can provide a steady stream of wireless energy for electronic devices in different environments.Rectenna are generally used as the receiving part of the microwave wireless energy transmission system.However,the existing antenna forms have low gains and it is difficult for the rectifier circuit to maintain high conversion efficiency at high input power,resulting in low receiving rectification efficiency,and If the impedance matching between the load and the rectenna cannot be guaranteed,the rectification efficiency will also be lowered.In response to these shortcomings,this article aims to achieve high receiving rectification efficiency,and conducts research on the design technology of microwave rectenna arrays based on metasurfaces.The main research work is as follows:(1)High-efficiency metasurface antenna array design researchAiming at the problems of low gain and low receiving efficiency of existing antenna forms in microwave energy transmission,periodic metasurface units are used to replace traditional antenna forms to improve the receiving efficiency of the microwave energy transmission system.First,the metasurface unit is optimized based on the equivalent model of the metasurface antenna unit,and a metasurface unit that can theoretically receive nearly 100%of electromagnetic energy is obtained.Then,the feeder network is designed by stripline,and the 4×4 metasurface antenna array is gradually optimized.The simulation and experimental test results show that the designed metasurface antenna array has a 5.87% improvement in receiving efficiency compared with the traditional air microstrip antenna,which verifies the feasibility of replacing the traditional antenna form with a metasurface antenna to improve the receiving efficiency of the microwave energy transmission system.(2)Design of dual-diode rectifier circuit with high conversion efficiencyAiming at large input power and high conversion efficiency,the rectifier circuit is designed with a parallel dual-diode topology.First,complete the optimized design of harmonic suppression network,band-stop structure,and impedance matching network.Then,the layout-principle diagram co-simulation method is used to analyze the rectifier circuit of the double diode to make the simulation result more accurate.Finally,an experimental platform was built and measured that when the input power of the dual-diode rectifier circuit was32 d Bm,the reflection coefficient was-22.97 d B,and the rectification efficiency was 63.84%,meeting the requirements of maintaining high-efficiency rectification under high input power.(3)DC synthesis technology of metasurface rectenna arrayBuild a microwave energy transfer experiment platform for metasurface rectenna sub-array,establish its nonlinear equivalent model based on the test data,and analyze the efficiency curve and volt-ampere characteristic curve of the metasurface rectenna array after seriesparallel connection under different conditions.From the perspective of ideal power supply series and parallel connection,the basic principles of series and parallel connection of metasurface rectenna arrays are proposed.Finally,according to this principle,a seriesparallel scheme design of a metasurface rectenna array is completed.The results show that the series-parallel scheme not only improves the DC synthesis efficiency,but also enhances the load capacity.