Research On Microwave Energy Transmission Technology Based On Flexible Materials

Microwave power transmission technology is one of the hot technologies in the field of electrical technology.It realizes point-to-point power transmission in free space by converting energy into microwave form.With the continuous development of wireless communication technology,microwave power transmission technology has been studied in solar power plants,wireless sensor networks and unmanned aerial vehicles.In recent years,flexible electronics technology has attracted wide attention in the field of conformal integration due to its advantages of thin thickness,light weight,bending and extensibility.The combination of flexible electronics and microwave energy transmission technology can make the receiving end of the energy supply system close to the carrier surface,so as to effectively save the installation space,reduce the system volume,and further improve the application convenience of microwave energy transmission technology.Therefore,the research on microwave energy transmission technology based on flexible materials has far-reaching strategic significance and prospect.This paper focuses on the microwave power transmission technology based on flexible materials,combined with practical application requirements,corresponding to the X-band microwave power transmission system for non-planar support surface.The main work is as follows :Research on high efficiency microwave rectifier circuit.Based on the closed-loop equation theory of rectifier diodes,the conversion efficiencies of different types of rectifier diodes are analyzed,and the rectifier diodes with the best rectifier performance are selected.By using parallel microstrip stub direct-pass filter to reduce the impact of parasitic parameters,while reducing costs make the circuit more practical;Class F and compact harmonic suppression network are introduced to reduce the insertion loss and size of rectifier circuit.The simulation optimization and experimental test of the rectifier based on conventional materials and flexible materials are carried out respectively.The experimental results show that the conversion efficiency of the rectifier based on conventional materials can reach 58 %,while that of the rectifier based on flexible materials can also reach 52 %.A novel microwave receiving antenna suitable for non-planar carrier surface is studied.The microstrip patch antenna unit is designed according to the principle of microstrip antenna.Considering the receiving power of the antenna unit and the power density distribution of the receiving surface,1 unit,1 × 2 unit and 2 × 2 unit arrays are designed respectively.The beam scanning theory is used to design the phase excitation of the feed network so that the array factor can achieve plus or minus 45° beam deflection in the H plane,thereby changing the maximum beam direction of the array antenna so that it can maintain high-efficiency reception for different beam incident angles.The simulation design is basically consistent with the experimental results,and the beam deflection of the rectifier receiving array antenna can be realized by changing the phase shift length of the feed network.Research on the microwave energy transmission system of the cylindrical body of the conformal aircraft.Establish the output power analysis model of the microwave energy transmission system,and based on the idea of maximizing output power,design the adaptive and optimized layout of the non-planar rectenna array.The designed pyramid horn antenna is used to realize the microwave energy radiation of the narrow beam,and the rectifier antenna array is designed by considering the cylindrical power density and the incident angle of the beam.The research results show that the microwave-to-DC conversion efficiency of the new beam deflection rectenna array can reach 29.04%.