Thermal Design Of Spaceborne Active Phased Array Antenna Based Structural-Electromagnetic-Thermal Coupling

Spaceborne Active Phased Array Antenna(APAA)has a very important application in environmental monitoring,space communication,navigation and other fields,benefit from the advantages of high reliability,powerful function and others.Spaceborne APAA always running in a special environment,the antenna temperature will be seriously affected by Solar radiation and high-power devices inside the antenna,such as T/R module,Overheating or excessive temperature differentials can lead an impact to the radiation performance of antenna,or worse,disable the antenna.With the trend of spaceborne APAA towards to high frequency,high precision,integration and so on,the efficient thermal control technology of spaceborne APAA severely restricts the research of next generation high performance spaceborne APAA.This thesis take a spaceborne APAA as the research object,aiming at the problem of overheating or excessive temperature differentials,proposed a heat pipe design method for phased array antenna based on the thermally-induced device performance drift,and an electromagnetic performance oriented integrated optimization method of spaceborne phased array antenna,based on the Structural-Electromagnetic-Thermal(SET)Coupling theory of APAA,the effectiveness of the method is verified by the simulation analysis.the author's major contribution can be summarized as follows.(1)The author summarizes the domestic and overseas advance of the thermal design for the phased array antenna from three aspects,system-level,component-level and chip-level.On this basis,the preliminary thermal design of antenna has been proposed,and the thermal analysis model of the antenna is established,in consideration of the structural characteristics of the antenna,after then,the feasibility and rationality of the preliminary thermal design scheme were verified by thermal analysis and electrical performance calculation of the antenna,the results show that the scheme can dissipate heat from the antenna T/R components,which laid a foundation for the further thermal design and optimization of the antenna.(2)On the basis of a series of previous studies on the axial groove heat pipe,the factors affecting the heat pipe's heat transfer performance are summarized.These factors include size,deformation process,vacuum degree,liquid filling rate and other factors of their own,in addition,there are also heating power,working angle,cooling conditions and other external environmental factors.On this basis,a heat pipe design method for phased array antenna based on the thermally-induced device performance drift is proposed,which can reduce the influence of bending on heat transfer performance of heat pipe,and make better use of heat pipe's high thermal conductivity to realize efficient heat dissipation of devices such as phased array antenna T/R components,so as to reduce antenna's gain loss,and guarantee the electrical performance of the antenna.Simulation results show that at the end of the working week,the maximum temperature of T/R component can be reduced by more than 3?,and the temperature difference can be controlled within 3?,and also,the gain loss can be controlled within 0.5 dB,after adopting this method.(3)An electromagnetic performance oriented integrated optimization method of spaceborne phased array antenna has been proposed.Firstly,the sensitivity analysis of various parameters in the thermal control structure is carried out to determine the key parameters that affect the heat dissipation effect of the antenna,then the comprehensive optimization model was established by taking the key parameters as the optimization variables,taking electromagnetic performance and weight as the comprehensive optimization goal,taking the maximum temperature,temperature consistency of T/R component and others as constraints.In the end,the optimal design parameters are obtained after the optimization calculation,while ensuring the antenna's gain loss is less than the engineering allowable value(0.5 dB),reduce the quality of antenna structure of thermal control system.According to the results,the gain loss can be controlled within 0.5 dB at the end of the working week,under the circumstance of the number of heat pipes is reduced by 4 and the thickness of heat dissipation plate is reduced by 1 mm,the validity of the method is verified.