The Optimal Subarray Method For Digital Array Radar Antenna

In large-sized digital array radar antenna,in order to improve the radar detection range and anti-jamming performance,it is often necessary to increase the number of array elements and use an array antenna composed of thousands of array elements.If each array element is individually designed and adaptive beamforming is performed,it will increase the difficulty of system design and manufacturing cost,which is difficult to achieve in actual engineering.So the subarray technology is proposed.The research of subarray optimization technology is mainly divided into two directions,one is the research of subarray division method,and the other is the research of subarray level adaptive beamforming.The adaptive beamforming is carried out at the subarray level,and the subarray partition method is studied for the purpose of reducing the sidelobe level.Subarray partition can reduce the complexity and computational complexity of the feeder network,so it is of great significance to carry out research on subarray optimization methods.The main research content and result are as follows:1.Proposing a flexible adaptive null broadening beamforming based on symmetrical nonoverlapping subarray.When the adaptive antenna array encounters motion interference,the interference may overflow the null position which leads to a sharp decline in the output performance.At present,most of the solutions are to widen the null to improve the faulttolerance of interference incidence angle.This will consume more degrees of freedom of the antenna array.For the adaptive antenna array with large number of elements,although it can provide enough degrees of freedom,the computational complexity is very large.To solve the above problems,a flexible adaptive null broadening beamforming based on symmetric nonoverlapping subarray is proposed in this paper.The proposed method has three main contributions.The first is to widen the null to suppress the motion interference.Secondly,the proposed method flexibly controls the wide null according to the actual needs to reduce the waste of degrees of freedom.Finally,subarray level adaptive beamforming is used to replace element level adaptive beamforming,so as to reduce the computational complexity of the method.Simulation results verify the high performance and effectiveness of the proposed method.2.A novel optimal subarray partition method based on iterative Fourier transformhierarchical clustering algorithm is proposed.In order to reduce the antenna manufacturing cost and the complexity of the feed network,it is usually necessary to divide the large array into subarrays.According to the Fourier transform relationship between the array element excitation and the array factor,the array element excitation is optimized by the method of Fourier transform to reduce the sidelobe level.Finally,the clustering algorithm is used to cluster the array element excitation to obtain the array to obtain a subarray level pattern with good performance.In the clustering algorithm,since the initial clustering center has a great influence on the clustering results,this paper proposes the subarray partition of the iterative Fourier transform-hierarchical clustering algorithm.Each subarray has the same excitation amplitude,thereby reducing the number of channels required for reception.While optimizing the subarraylevel adaptive pattern,compared with the intelligent optimization algorithm,the iterative Fourier transform algorithm can greatly reduce the run time.The MATLAB experimental simulation verifies the usefulness and practicality of the proposed method.