| MPT is a wireless energy transmission technology that is suitable for high power,long distance,and less affected by the atmospheric environment.An important indicator to measure the quality of a MPT system is the system efficiency,among which the microwave energy space transmission efficiency between the transceiver antennas is an important part of the system efficiency.For the use of array antennas to construct transceiver antennas for MPT systems,the matrix analysis method based on microwave networks can effectively analyze the spatial transmission efficiency of transceiver array antennas.However,it is difficult to obtain the scattering matrix parameters in microwave networks,which limits the application of this method in the analysis of spatial transmission efficiency of large-scale transceiver array antennas.At the same time,how to reasonably design the excitation distribution of the transmitting antenna to maximize the spatial transmission efficiency of the transmitting and receiving array antenna.In view of the above problems,this paper will carry out the transmission efficiency analysis and optimization design research of transceiver array antenna based on microwave network.The main work is as follows:1.Transmission efficiency analysis of transceiver array antenna based on microwave network.The array elements of the transceiver array antenna are equivalent to the ports of the microwave network,and the multi-port microwave network model of the transceiver array antenna is constructed,and the efficiency characteristics of the transceiver array antenna energy transfer are studied.Firstly,the mathematical relationship between the parameter matrix of the microwave network model and the total input and output microwave energy is analyzed,and the transmission efficiency equation of the array antenna system is derived.In the microwave network model,it is difficult to obtain the parameters of the scattering matrix.A method is proposed to solve the parameters of the scattering matrix by combining the phase center of the antenna element and the Friis equation.The scattering parameters between a pair of air microstrip antenna elements at different transmitting and receiving positions are analyzed in a case.The results show that the maximum error between the scattering parameters calculated by this method and the simulation results is within 4%.Then the method is applied to the transmission efficiency equation of the transceiver array antenna.In the case where the transceiver antennas are all 3×3 square arrays and the transceiver distance is 5m,the calculated transmission efficiency is 2.92%,which is different from the efficiency calculated by the Friis equation(2.96%)are basically consistent,which verifies the correctness of the transmission efficiency equation of the transceiver array antenna based on the microwave network.2.The design of the excitation distribution of the transmitting array antenna for the high transmission efficiency of the transmitting and receiving antenna.Based on the transmission efficiency equation of the transceiver array antenna in microwave network,the design of the excitation distribution of the transmit antenna for high transmission efficiency is studied.Firstly,an optimization model is established with the maximum transmission efficiency of the transceiver antenna as the optimization goal,the excitation amplitude of the transmitting array element as the optimization variable,and the optimization model considering constraints such as the excitation taper of the transmitting antenna and the flatness of the power distribution at the receiving end of the receiving antenna.For problems that are difficult to solve,k-means clustering is used to classify the excitation amplitudes of the transmitting array elements to reduce the number of optimization variables.Taking a large-scale transceiver array antenna composed of 137 transmitting array elements and 961 receiving array elements as an example,the optimization results show that,without considering constraints,when the number of optimization variables k increases from 1(uniform excitation distribution)to 7,the maximum The transmission efficiency increases from 51.01%to 57.9%;when k=7,after considering the constraints of the power distribution flatness at the receiving end of the receiving antenna,the transmission efficiency decreases from 57.9%to 32.46%,and the mean square value of the power distribution flatness at the receiving end changes from 0.247 is reduced to 0.026,which indicates that the uniformity of the power distribution at the receiving end of the receiving antenna can be greatly improved at the expense of transmission efficiency.3.High transmission efficiency design of transceiver antenna under moving target reception.Based on the optimization model of the excitation distribution design of the transmitting array antenna,the high transmission efficiency design of the transmitting and receiving antenna is studied when the receiving antenna is the moving target.Firstly,by introducing the position information of the receiving antenna into the corresponding matrix parameters of the microwave network model,the beam scanning of the transmitting array antenna based on the microwave network is obtained;Taking the maximum average transmission efficiency of the receiving antenna in multiple positions as the optimization goal,the excitation amplitude of the transmitting array element is the optimization model of the optimization variable.Taking the dynamic displacement process of the receiving antenna at the beam scanning angleφs from 0 to 90° as an example,the average transmission efficiency of the receiving antenna at the five positions φs=0°、22.5°、45°、67.5° and 90° can reach 46.18%,which is only better than the theoretical one.The transmission efficiency(46.94%)is reduced by 0.76%. |
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