Research On High Temperature Resistant Technology Of Conformal Load-Bearing Antenna

With the development of science and technology,aircraft will enter the age of hypersonic.The fast flying speed of a hypersonic vehicle causes the skin to withstand the pressure load and at the same time generates a temperature of hundreds or even thousands centigrade of strong friction with the air.In order to reduce the influence of the aerodynamic heating,the aircraft is usually designed as a flat structure.However,when the loading capacity of weapons is maximized,the space reserved for the antenna system will be greatly reduced.In order to save the space inside the aircraft,the antenna system needs to be conformally designed with the fuselage.The conformal load-bearing antenna is a new type of antenna that is capable of conforming to the vehicle and load-bearing capacity,as well as excellent electrical performance.According to the external load environment characteristics of the hypersonic vehicle,this article will develop the high temperature technology of the conformal load-bearing antenna for the hypersonic aircraft platform.First,metal and dielectric materials with high temperature resistance are selected,and the high temperature resistance characteristics of the microstrip antenna elements are analyzed.In order to solve the problem of S₁₁ frequency deviation caused by changes in electrical parameters of materials after temperature changes,a microstrip antenna unit structure with high temperature resistance characteristics is provided by wideband technology,and the working bandwidth reaches 5%over the entire operating temperature range of 20 to 1000°C.Parametric analysis shows that the patch length,skin thickness,substrate thickness,air layer thickness,and slot size have a significant effect on the electrical performance of the antenna.Microstrip antenna unit is tested at room temperature.The measured working bandwidth reaches 6.8%,indicating that the broadband microstrip antenna unit has excellent wideband characteristics.Second,using microstrip antenna elements to build a 1x8 high temperature conformal load-bearing array antenna structure,through the analysis of electromechanical heat interaction relationship,proposed electromechanical thermal coupling analysis method.Firstly,temperature-pressure multiphysics sequential coupling analysis of the high temperature conformal load-bearing array antenna structure is performed to obtain the structural deformation data;then the deformed antenna structure data is surface-fitted to construct a deformed antenna structure under the effect of temperature and pressure;finally,the electromagnetic simulation software is used to analyze the electrical performance of the antenna after deformation.The results shows that there is a one-to-one relationship between the deformation and the electrical performance of the antenna structure.When the deformation exceeds 0.56mm,the average S-parameter will be greater than-15dB.Finally,for the 1x8 high temperature conformal load-bearing array antenna structure,the large amount of deformation caused by temperature and pressure will affect the electrical performance.This thesis proposes a optimization method to improve the strength of the antenna structure,reduce its deformation,and then meet the electrical performance requirements.By constructing a structural optimization design model of the conformal load-bearing array antenna with stiffeners,the antenna structural deformation is taken as a constraint,and the weight of the antenna structure is the target to optimize the design of the model.At the same time when the mechanical and electrical properties of the antenna are satisfied,the weight of the antenna structure is increased by 103.63%by increasing the thickness of the ground plate.The weight of the 1x8 high temperature conformal load-bearing array antenna with stiffeners only increases by 10.15%.