The Sparse Synthesis And Optimization Of Large Scale Antenna Arrays

Due to the advantages of high gain,narrow beam and strong ability of beam steering,the large-scale array antennas have been applied more and more extensively in the modern radar and wireless communication systems.Meanwhile,in order to reduce the cost and system complexity,the large array antennas are expected to be designed with sparse arrays,whose elements are as little as possible.However,the existing design methods still face some challenges.The thesis studies several key technologies in the design of large array from the angle of practical application,which includes sparse array synthesis,sparse array synthesis of multiple patterns in wide angle scanning and wideband,fast analysis and sparse optimization of phased array antennas with the influence of mutual couplings.Furthermore,this thesis emphatically studies on the application of sparse reconstruction in the synthesis of large array antennas.The main works and innovative points of the thesis are given as:The first chapter examines the sparse synthesis of array antennas with the principle of the unitary matrix pencil method(UMP).We give the conventional mathematical expression of the problem of the synthesis of sparse array antennas.This thesis examines the problem of maximally sparse array synthesis from the point of view of sparse signal processing.For the existing problem of the matrix pencil method(MPM)and forward backward matrix pencil method(FBMPM)in the synthesis of sparse array pattern,the UMP method is proposed to effectively solve the problem.Several shaped-beam patterns of sparse array antennas validate the effectiveness of the proposed method.The second chapter studies the optimization and synthesis of sparse linear array.Moreover,we extend the UMP method to the synthesizing problem of multiple patterns in wide angle scanning of sparse linear arrays.The extended unitary matrix pencil method(EUMP)is proposed for finding the common element positions and individual element excitations for multiple patterns.The EUMP method is also extended to the synthesis of wideband sparse linear array.The extended generalized UMP method(EGUMP)is presented to realize the optimization of sparse linear array in wideband and wide angle scanning.The third chapter gives the research of the optimization and synthesis of sparse planar array.The 2D unitary matrix pencil method is proposed for pattern synthesis of planar arrays.A fast synthesis method based on the acceleration technique of SVD for decomposed sampling Hankel matrices is proposed for large-scale sparse planar arrays.By virtue of SVD the decomposed sampling pattern matrices,the solution time of the generalized eigenvalue can be accelerated.Meanwhile,the proposed method expands the computed array size and improves the efficiency of the matrix enhancement and unitary matrix pencil(MEUMP)method.Moreover,we extend the MEUMP method to the synthesizing problem of multiple patterns in wide angle scanning of sparse planar arrays.We do further research on the relation between the sparseness rate and array size and scanning angle for sparse planar arrays with low sidelobe level.Moreover,the extended MEUMP is proposed for the multiple pattern synthesis of wideband and wide angle scanning.The forth chapter examines the optimization of sparse array with the consideration of mutual couplings.Due to the lack of the mutual coupling among array elements for the array factor formulation,the optimized result of sparse array will have some difference from the actual desired array pattern of engineering application.Firstly,the full wave analysis method is studied to effectively simulate the radiating characteristic of large scale array antennas.The space mapping method is combined for the design of low sidelobe level sparse arrays.The optimization of large scale sparse array with the UMP method is exploited to the coarse model.The full wave analysis method is used for the fine model.The mapping relationship between the coarse and fine model is established to optimize the low sidelobe level in wide angle scanning of the large sparse array with the influence of mutual couplings.