| Vehicle-mounted phased array radar is an important military equipment of our country.As the core component,the design of array antenna’s high-quality configuration plays a vital role in the realization of high-performance,lightweight,and low-complexity feed system radar systems.Non-uniform arrays(such as sparse array,thinned array),as an effective array antenna layout form,contribute to the lightweight and performance improvement design of the array antenna.In the optimization design of the non-uniform array antenna layout,the change of the array layout form will cause the change of the mutual coupling effect among array elements,and the optimization method of the conventional weak coupling array antenna layout design cannot guarantee the accurate design of its performance.Therefore,researching and establishing an optimization method for the layout design of non-uniform array antenna considering the mutual coupling effect has become a key issue that needs to be solved.This paper proposes a method for the optimization of the layout of a strong coupling antenna array based on the analysis of the parametric method of moments,which is used in the design of planar non-uniform array antennas.The main research contents include:(1)Based on the parametric moment of method,the formulation and solution method of the optimization problem of the non-uniform layout design of the array antenna considering the mutual coupling effect is established.First,a general optimization model for the non-uniform layout design of the array antenna is given.In order to accurately consider the influence of the change of the array layout form on the change of the mutual coupling effect between the array elements,a parametric method of moment analysis model based on coordinate mapping and suitable for the non-uniform layout design of array antenna is constructed.Based on the adjoint method,the general formulation of the sensitivity information of the objective function on the design variables is analytically derived.The gradient optimization algorithm that can use the sensitivity information is used to solve the optimization problem,and the general process of the optimization problem solving method is given.(2)An optimization method for the layout design of loop array antennas considering the mutual coupling effect is established.Specifically,an optimization model and solution method for the layout design of the sparse concentric ring array antenna for high main lobe gain and low side lobe level design are established.Numerical example results show that the established method can effectively solve the layout optimization problem of sparse concentric ring array antennas.The numerical simulation results demonstrate: Compared with the design method based on genetic algorithm,the established method can effectively solve the layout optimization problem of the sparse concentric ring array antenna,while maintaining the radiation performance of the antenna array.Facing the miniaturization design requirements of loop antenna arrays,based on the established optimization model of the sparse concentric ring array antenna,the axial ratio and the position of the array element on the elliptical ring are additionally introduced as design variables,and the sparse concentric elliptical ring array is established.And a new sparse concentric elliptical ring array antenna layout form is designed.Numerical results show that: compared with the optimized results of the concentric ring array antenna,the designed concentric elliptical ring array antenna not only has a smaller aperture area,but also has improved radiation performance(3)A pattern synthesis method of thinned array antenna based on topology optimization idea is proposed.The basic idea is that regarding the optimization problem of thinned array antenna design as an equivalent topology optimization problem considering whether the conductor material exists in each array elements.An optimization model for thinned array antenna layout design with the objective function of maximizing the radiated energy difference between the main lobe and the side lobe is established.In order to use the gradient algorithm to solve the optimization problem,and to effectively characterize the infinite difference in impedance characteristics between the conductor material and the insulating material,a tangent material interpolation model with self-penalty function is introduced to automatically obtain a discrete solution of the 0-1 distribution.Based on the established optimization method,the layout of typical thinned square arrays and thinned circular arrays is designed,and the influence of the number of excited array element on the radiation performance of the array antenna is studied at the same time.Finally,the necessity of further synthesizing sparse array based on sparse array is discussed. |
