Research On The Contoured Beam With Single-shaped Reflector Of Three-layer Cable Net Structure And Prototype Development

In the field of modern aerospace,in order to meet some application requirements of space communications and electronic reconnaissance,the satellite-borne antennas with beamforming capabilities have become a research hotspot of various scientific research institutions at home and abroad due to their advantages of high gain and high energy utilization.Considering the shaped-reflector design technique applied to deployable mesh antennas,there are two problems need to be solved in this paper.The first is how to determine a concave-convex shape of the shaped-mesh reflector.And the second is how to construct a three-layer shaped cable net configuration and design its pretension.In view of these problems above,this paper has carried out the optimization design of shaped-mesh reflector,the form-finding design of three-layer cable net structure,and development and experiment of the prototype.The main works can be described as follows:1.An optimization design method based on the function expansion method is proposed to design a shaped-mesh reflector.Firstly,the grid division of a paraboloid is completed according to some structural parameters of the mesh antenna.And an initial paraboloid cable net structure is obtained by using the method of force density for form-finding design.Secondly,a shaped reference reflector is introduced in the optimization process,and its shape is described by Jacobi-Fourier orthogonal polynomial.Then,a concave-convex shape of the mesh reflector is adjusted by optimizing some polynomial coefficients.Finally,based on the structural forms of offset reflector and rotationally symmetric reflector,the shaped-mesh reflectors are designed for two coverage areas of the U.S.map and the China map.The results of numerical examples all meet the design requirements of far-field pattern,which verifies the effectiveness of the optimization method proposed in this paper.2.In order to realize the concave-convex shape of a mesh reflector in structure,this paper develops an improved reflector antenna model with three-layer cable net structure based on previous research of the research group.Starting from two aspects of simplifying the structure of the three-layer cable net and improving the uniformity of tension distribution,a morphological analysis method for the three-layer shaped cable net structure is proposed by combining the equilibrium matrix method and a topology optimization ideas.This technique first establishes a tension optimization model based on the equilibrium matrix method.On eliminating redundant digging cables during the loop iterations,a simplified three-layer cable network is updated.Through simulation calculations,the morphological design results of the offset and symmetrical three-layer cable net reflectors are determined.The results show that the number of digging cables is significantly reduced,and the tension distribution is more uniform in the cable net structure considering topology optimization.3.Using the morphological design results of this paper as a manufacturing case,this paper has carried out development of a prototype physical model with aid of the existing equipment in this laboratory.During the manufacturing process,some machining errors lead to a certain deviation between this actual prototype model and the design shaped reflector.Therefore,the V-STARS photogrammetry technology is used to measure and adjust the shaped-mesh reflector for meeting a precision requirement.The experimental results on the one hand demonstrate the rationality of the prototype development method.On the other hand,they also verify the effectiveness of shaped-mesh reflector antenna design technique proposed in this paper.