Research On Electromechanical And Thermal Coupling Of Ground-Based Reflector Antenna Based On Surface Heat Flow Model

Reflective surface antenna has the advantages of low cost,simple structure,and small obstruction of airborne electromagnetic waves by the feed source,so it has been widely used.With the deepening of scientific exploration,higher requirements are placed on the sensitivity and resolution of the antenna system.In order to improve the sensitivity and resolution of the antenna,it is necessary to increase the effective receiving area of the antenna and reduce the noise of the antenna system.While the effective receiving area of the reflector antenna increases,it also brings about the problem of the structural deformation of the antenna surface under the action of solar radiation,which restricts the electrical performance of the antenna.In this thesis,the following three aspects of the reflective surface antenna are investigated with respect to the temperature field under solar radiation on the deformation of the antenna profile and the effect on the electrical performance of the antenna.Firstly,based on the solar radiation law and the theory of reflective surface antenna structure,the heat flow model of the main reflective surface of the reflective surface antenna is established by considering the shading of the antenna due to the position change in actual operation;based on the heat flow model of the main reflective surface,the heat flow model of the secondary surface of the reflective surface antenna is established by using reflection theory and distance inverse interpolation method.The heat flow model of the reflector antenna is revised through simulation analysis,and it is verified that the surface heat flow model can quickly solve the antenna surface heat flow within the guaranteed error range of less than 5%.Secondly,the influence of the external environment and the antenna’s own factors on the heat flow and temperature field of the reflector antenna during the actual operation of the antenna is analyzed.According to the influence law,a method of using the surface heat flow model to predict the extreme temperature field of the antenna is proposed.This method is used to predict the extremely high temperature,extremely low temperature,maximum temperature gradient and "solar cooker" effect of a 7.3m antenna.Combined with the relevant experimental data of the 7.3m antenna,the rationality of using the heat flow model to predict the extreme conditions of the antenna is verified.Finally,the thermal deformation of the 7.3m antenna under extreme temperature field conditions is simulated and the far-field directional diagrams of the deformed antenna surface under different extreme conditions are solved.Aiming at the problem that the main lobe of the antenna is shifted in the maximum temperature gradient condition,a method for optimizing the coverage area of the antenna surface coating based on the heat flow model is proposed.The optimization results show that the antenna surface temperature gradient is reduced by 9.8% under the maximum temperature gradient condition and the main flap pointing offset due to thermal deformation is reduced by 0.07° after the optimization of subregional coverage.