Co-simulation Research On Electric And Thermal Of Microwave Device Based On Finite Element Method

With the rapid development of the aerospace field and wireless communication technology,complex microwave devices such as vacuum electronic devices and high-power microwave antennas have received extensive attention and have been applied to various fields.Due to the trend of equipment miniaturization and precision requirements,the military and civilian fields have an increasing desire for high-performance microwave electronic devices,and the heat dissipation performance of devices is more and more difficult to ignore in the design of high-performance microwave devices.For microwave electronic devices,their electromagnetic and thermal characteristics are not independent of each other.It is not enough to consider only the electromagnetic factors of microwave devices for the design of high performance microwave electronic devices.However,the coupling between the electromagnetic solution module and the thermal solution module of the current mainstream dimensional wave electromagnetic simulation software is not close,which reduces the authenticity and reliability of microwave device simulation.As a result,the accurate electrothermal simulation analysis in the real sense can not be realized,which greatly limits the development of high-end devices in China.Therefore,it is imperative to study the co-simulation on electric and thermal technology for microwave electronic devices.In this paper,electromagnetic and thermal theory is combined with simulation calculation.Based on the finite element method and the existing electromagnetic and thermal simulation software foundation,a kind of co-simulation calculation method on electric and thermal for microwave tube is proposed,and the nonlinear simulation technology of microwave devices is further studied.The main contents of this paper are as follows:1.Base on the existing electromagnetic solver and thermal solver,for the different structures of high-power microwave tubes,the electro-thermal synergy technology for the focusing system and the collector is studied separately,and the seamless connection between the electric and thermal solutions is realized.,And proposed an inaccurate Newton-Raphson iterative method to further improve the calculation efficiency of thermal simulation analysis.2.Base on the existing thermal solver,taking into account the nonlinear problem in thermal analysis,further improve the existing thermal solver to realize the material nonlinear solution function and the contact thermal resistance nonlinear solution function.Taking into account the dual non-linear problems caused by the temperature-dependent thermal conductivity and contact thermal resistance,this paper introduces an iterative method of functional minimization technology to further speed up the solution of thermal finite element analysis.3.Base on the existing electromagnetic,thermal and mechanical solvers,further study the influence of temperature factors on the electromagnetic performance of microwave devices.Based on the temperature-sensing characteristics of the electromagnetic parameters of the material,and on the basis of the existing temperature field results,the electromagnetic solution process of the microwave device is returned to explore the influence of the material nonlinearity on the electromagnetic characteristics of the microwave device;based on the thermal expansion and contraction effect of the material,the use has been Some mechanics solvers calculate the thermal deformation of the existing temperature field,and re-model the calculation in the electromagnetic solver to explore the influence of temperature deformation on the electromagnetic characteristics of microwave devices.