Research On Conformal Array Sparse And Pattern Synthesis Algorithms

Conformal array have the unique advantages of low profile,wide beam coverage,low radar cross section,and no impact on the aerodynamic performance of aircraft.It has been widely used in civil and military fields.In practical applications,conformal array synthesis involves controlling the number of array elements,the position of array elements,the excition amplitude and phase and other parameters to achieve low sidelobe pattern or desired radition characteristics.In the paper,covariance matrix adaptive evolutionary strategy optimization algorithm(CMA-ES)is used to optimize the sparse distribution of conformal array and pattern synthesis.The main research results of this paper can be summarized as follows:In the second chapter,we first establish the mathematical model of arbitrary conformal array and give the calculation method of far-field pattern of conformal array.Then,the electrical parameters of the antenna array and the basic principle and operation flow of the covariance matrix adaptive evolution strategy are proposed.In the third chapter,several typical conformal array models are established,and the array pattern is analyzed by extracting the element pattern simulation data.The calcution results are in good agreement with the full wave simulation results.CMA-ES algorithm is used to optimize the sparsity of low sidelobe pattern for cylindrical conformal array with elements arranged on fixed grid points.In the spherical conformal array,the deep null caused by polarization cancellation is avoided by rotating the element.We propose a rotational symmetry optimization method to realize sparse distribution of spherical conformal arrays,and analyze the influence of the number of regions and sparse distribution rate on the array performance.In the fourth chapter,conformal array pattern synthesis based on mutual coupling is studied.The concept of active element pattern(AEP)is applied to conformal array pattern synthesis,and the mutual coupling is considered.Firstly,the theory of AEP is introduced,and then an efficient method extracting from HFSS is introduced.Then,the amplitude and phase of the conformal ring array are optimized to realize the low sidelobe pattern and beamforming.Finally,for the low sidelobe pattern optimization of cylindrical and spherical arrays with large number of elements,an improved Bornstein polynomial is introduced,the effectiveness of the proposed method is proved by simulation examples.