Beamforming Algorithm Based On Dual Polarized Conformal Array

Compared with the traditional array antenna,the conformal array has many advantages such as not changing the aerodynamic shape of the carrier platform,large beam coverage and small scattering cross section,etc.Beamforming is an important technique to realize high gain and anti-interference of array antenna.However,the performance of the traditional beamforming algorithm will be seriously reduced when there are main lobe interference,strong desired signal and inaccurate desired signal parameters.The beamforming algorithm based on the conformal array is more complex than that based on the planar array due to the inconsistencies of the orientation and polarization characteristics of each antenna element in the conformal array.The dual-polarization antenna has two independent orthogonal polarization signal transmitting and receiving channels,which can realize the freedom of processing and identifying the polarization information of the electromagnetic signal,and enhance the processing ability of the array signal in the polarization domain.This paper focuses on the research of beamforming problem based on dual-polarized conformal array.The main contents of this paper include:Firstly,the basic principle of adaptive beam technology is introduced,and the influence of main lobe interference,strong desired signal and desired signal parameter error on the performances of the beamforming algorithm are analyzed by simulation under uniform array model.Secondly,a joint spacel-polarization domain beamforming algorithm is proposed based on dual-polarized conformal array.According to the projection of polarized signal in the local coordinate system of each antenna unit,the steering vector of the dual-polarized conformal antenna array is reconstructed,the steering vector of the array antenna is extended from the original N dimension to 2N dimension(N is the number of array elements),and the corresponding signal space is separated into two orthogonal polarized signal spaces.On the basis of combining the signal state of polarization,build the space-polarization joint domain steering vector,the traditional space beamforming algorithm is extended to the space-polarization domain,The proposed algorithm can not only solve the traditional interference problem of the main lobe,but also suppress the interference from the same spatial direction as the desired signal when the desired signal gain is ensured.Finally,a robust beamforming algorithm based on convex optimization theory is proposed to solve the inaccuracy of the desired signal direction.In order to ensure the gain of the desired signal direction,all the signal gains in the region can be guaranteed by adding multiple constraints in the region containing the real expected signal.The algorithm can effectively enhance the signal and suppress the interference even if there is error in the desired signal direction.