Research On Beamforming Technology Of Array Antennas

With the increasingly maturity of wireless communication systems,the design of array antennas has been paid more attention,and its beamforming has become the focus of research.This thesis focuses on the beamforming of anti-jamming array antennas and conformal array antennas.A four-element anti-jamming array antenna with 0.3? array spacing is designed,and a new technique for beam null-forming is proposed;the conformal array antenna is designed,and its beam scanning technology is studied.The main works of this thesis are:1.Based on the mutual coupling between array elements,the active impedance and active pattern of array elements in anti-jamming array antenna are theoretically analyzed;the effect of mutual coupling on active standing wave and active pattern of array elements in fourelement anti-jamming array antenna is studied;the accuracy and depth of pattern nulling are improved by using the co-simulation of MATLAB and HFSS,and by using the combination of active pattern superposition theory and differential evolution algorithm;a four-element anti-jamming array antenna with 0.3? array spacing is designed,which verifys the correctness and feasibility of the technology.2.The circular-polarized conformal array antenna is designed and studied by using Vivaldi antenna as the array element.The circular-polarized characteristics of array elements is achieved by the “interleaving” arrangement of two line-polarized Vivaldi antenna with equal amplitude and phase difference of 90°,and its performance is analyzed in an infinite electromagnetic environment,which is simulated by using the master-slave boundary condition;the conformal array antenna is analyzed,and a 126×1 line-polarized linear array and a 90×1 line-polarized semicircular ring array are designed;in the linear array,the scanning beam(SLL<-13 d B)from 0° to 60° is achieved by adjusting the phase distribution reasonably;the inconsistencies of array elements in the semicircular ring array is analyzed by extracting the active pattern data of 90 array elements,the scanning beam(SLL<-18 d B)from 0° to 75° is achieved by using the co-simulation technology;a 9×9 circular-polarized beam-scanning cylindrical array is designed,and the validity of the design is verified by using the co-simulation technology.