Research On Beamforming And Synthesis Of Array Antenna

Large scale array antennas have attracted much attention because of their advantages over single antennas in array gain and beam scanning performance.However,due to the large number of its array units,its structure design is more complex and the manufacturing cost is high,which has become the key problem restricting its rapid development.The sparse array synthesis method can obtain almost the same beam as the full array with fewer array elements.By setting the position of the array elements,the side lobe level of the array antenna can be significantly reduced.On the other hand,rapid analysis of array antenna,calibration and diagnosis of amplitude and phase of array channel excitation also have important research significance.This paper focuses on the systematic research of large sparse array antenna and amplitude and phase calibration and diagnosis of array antenna,which mainly includes the following aspects:1.Sparse array synthesis algorithm based on probabilistic model optimization.This paper firstly researches the Iterative Fourier Technique(IFT)based on the synthesis theory of array antennas and the basic method of Fourier transform.It analyzes the advantages of using Fourier method to compute array array factors and array excitation information.It also discusses the iterative Fourier Technique(IFT)based on adaptive probability model.In other words,the comprehensive process of PLIFT(Probability Learning Iterative Fourier Technique)algorithm is researched and summarized,and then the fitness function model and the probability model of sparse array distribution are analyzed in detail.Therefore,the fitness function screening mechanism is introduced.More subtle and accurate division of the initial array is carried out to retain more antenna elements that have greater influence on the array.Finally,the PLIFT algorithm is improved.A more efficient FPLIFT(Fitness Probability Learning Iterative Fourier Technique)algorithm is proposed.2.The FPLIFT algorithm is applied to different array antennas for comprehensive verification.Firstly,it is applied to symmetric and asymmetric linear arrays.The numerical examples show that the FPLIFT algorithm maintains high efficiency and optimizes the comprehensive results.Low sidelobe sparse array synthesis with zero trap is optimized based on FPLIFT algorithm.Finally,the FPLIFT algorithm is extended to the synthesis of large planar sparse arrays,and an example proves that the FPLIFT algorithm also has a good effect on the synthesis of large sparse arrays.3.The FFT method has great limitations in solving the amplitude-phase calibration problem in the field of array antenna inverse problem.The range of its solution is only for array antenna whose array spacing is half of the working wavelength.Based on this,the channel excitation current inversion method based on ICZT algorithm is studied,which can be applied to equally spaced array and non-equally spaced array.A new method of amplitude and phase calibration and diagnosis for sparse array antenna is proposed by combining the sparse array element distribution model and the non-equidistant array direction graph calculation method,combined with FPLIFT and ICZT algorithm.Finally,a numerical example is given.The results show that the method is feasible for sparse array antenna calibration and diagnosis.