Integrated Simulation Of Electromagnetic-Thermal Effect Based On Domain Decomposition Method

With the rapid development of microwave device,the dielectric loss of its leads to thermal effect,which seriously affects the communication performance.The classical numerical method can be applied to analyze and solve general electromagnetic-thermal effect on a personal computer.However,the increasing complex simulation structures or large-scale problems will lead to some problems,such as lower efficiency,poor accuracy,etc.Therefore,it is important to research and design a new kind of fast algorithm.This paper is based on the finite element method to solve the electromagnetic-thermal effect,and then adding the domain decomposition method,which will divide the large-scale complex problems into small-scale simple problems and make parallel computing easily.This paper will introduce the following aspects:Firstly,in order to illustrate the structure principle of the system matrix between the FEM and the DDM.In FEM,the Maxwell equations are transformed into the electric field governing equation through the constitutive relationship.The appropriate basis functions are selected in the discrete simulation model.And based on the generalized variational principle,the electric field governing equation is transformed into a set of finite element linear equations.After the boundary conditions are determined,the spatial electromagnetic field distribution can be obtained by constructing and solving the finite element system matrix in the simulation area.The principle of constructing the system matrix in each subdomain in DDM is consistent with the FEM.Secondly,in order to improve the calculation efficiency in the thermodynamics section,this paper presents a steady-state electromagnetic-thermal domain decomposition method based on finite element method.This algorithm divides the thermal simulation area into some certain number subdomains,which is not overlap each other.Then,a thermal field Lagrange multiplier is introduced at the interface of neighboring subdomains.When the thermal Lagrange multiplier is solved,the temperature field distribution can be obtained.Finally,in order to observe the dynamic temperature change of simulation devices at any time,this paper presents a transient electromagnetic-thermal domain decomposition method.This algorithm rewrites the frequency domain steady-state equation into the time domain transient equation by transforming time differential equation into time difference equation.Then,by constructing finite element linear equation in each subdomain,the dynamic temperature changes can be obtained.