Lightweight Design And Uncertainty Analysis Of Large Phased Array Antenna Back Frame

Large phased array antennas have played a unique role in the areas of long-range early warning,astronomical observation,and deep space exploration.In order to more effectively improve the detection accuracy of large phased array antennas,it is very important to study and improve the antenna electrical performance indexes.In engineering practice,the deformation of the antenna back frame structure is one of the main reasons for the deterioration of the antenna's electrical performance.On the one hand,the antenna design requires that the quality of the back frame should not be too large,otherwise it will cause the rigidity of the antenna back frame to be reduced,and the structure of the antenna back frame will be deformed,which will eventually deteriorate the electrical performance of the antenna.On the other hand,the structure of the antenna back frame is affected by the uncertain factors,which will cause the structural uncertainty to deform and cause the fluctuation of the antenna's electrical performance.To this end,this paper uses a topology optimization method to propose a new type of antenna back frame to solve the contradiction between the weight index and the stiffness index of the antenna back frame,and to realize the lightweight design of the antenna back frame.On this basis,the interval analysis of the antenna pattern is carried out.The interval field model is used to measure the uncertainty of the service condition of the antenna back frame structure.The specific work of this article is as follows:(1)Based on the innovative prototypes of major projects of the National Natural Science Foundation of China,a new type of back frame structure is proposed based on the original back frame by using the topology optimization method.According to the original back frame's structural dimensions,load conditions,constraints and other boundary conditions,the initial model is established.In the topology optimization process,the minimum strain energy of the antenna back frame is used as the target function,and the volume ratio is the constraint function.The topology of the back frame.(2)The pre-deformation compensation of the new back frame was deployed and related structural and electrical properties were analyzed and verified.According to the topology of the new back frame,the new back frame model is obtained;according to the characteristics of the new back frame "large deformation at both ends,small deformation in the middle",the two ends of the new back frame are pre-deformed to improve the accuracy of the front.The static structure and electrical performance of the new back frame structure under various complicated working conditions such as dead weight,wind load,temperature load and simultaneous action of multiple loads were analyzed,and the accuracy and electrical performance of the array were analyzed and verified.The modal analysis of the new back frame is carried out to provide the fundamental frequency parameters of the structure.(3)An uncertainty analysis method for power pattern based on the interval field model is proposed.Aiming at the uncertain deformation problem caused by the large phased array radar antenna array under the uncertain conditions of wind load,snow load,etc.,the interval field model is used to describe the uncertain deformation of the array,which is coupled with the structure-electromagnetic coupling The combination of the models can solve the far-field patterns of large phased array antennas with different azimuth angles under the deformation with spatial uncertainty.Thus,the upper and lower bound representations of the antenna pattern under the influence of uncertainty deformation are obtained.