Research On Three Dimensional Near-Field Shaping Antenna Array

With the rapid development of microwave hyperthermia technology,near-field identification technology,logistics technology and other applications,electromagnetic field shaping is attracting more and more attention.With the development of method of maximum power transmission efficiency,we have been able to optimize the design of the system with fixed transmitting antenna array,receiving antenna array and transmission distance,and realize the shaping of near-field and multi-objective wireless energy transmission.In this dissertation,several antenna design methods based on method of maximum power transmission efficiency are described in detail,and the application background of different methods is clarified.At the same time,the electromagnetic field shaping in three-dimensional space is studied.The main contents of this dissertation are as follows:Firstly,three optimization design methods for the same antenna array are compared.Through three forms of MMPTE,including UMMPTE,CMMPTE and WMMPTE.Different methods are applied to a 2.45 GHz power transmission system respectively.6 × 6 array is selected as the transmitting antenna array and 5 elements along the "L" distribution array as the receiving antenna array.The power transmission efficiency and the near-field shaping effect of the three methods are analyzed and compared,and the necessity of receiving antenna design in power transmission system is emphasized.The power transmission system of UMMPTE can achieve the maximum transmission efficiency with system of fixed transmission array,receiving array and transmission distance.The system designed with WMMPTE can achieve the energy focus of five points discretely and the WMMPTE to design the multi-objective wireless energy transmission system shows a good advantage.The system designed with CMMPTE can be applied to the situation that the requirements for the position of receiving antenna are not strict,at the same time,it can achieve a flat top shaping effect.Compared with the general method,the transmission efficiency of the array antenna designed by the method described in this paper is higherSecondly,we use CMMPTE to realize the electromagnetic field shaping in 3D region.The 48 element antenna is chosen as the transmitting antenna array.We also did a research on the relationship between the testing array and the shaping effect,we found that the planar dipole array is more flexible.By determining the weighting coefficient matrix and re,we got the excitations of the transmitting array and designed the feeding network.The spherical and cylindrical near-field electromagnetic field is shaped by designing the test antenna and determining the weighting coefficient matrix.