Based On The Time Domain Finite Element Method Of Any Three-dimensional Structure Of The Electromagnetic Transmission Characteristics Research

Finite element method(FEM)because of its complex structure modeling ability and is widely used in solving many problems(including electromagnetic problems),physical field not only in the frequency domain with full development,in time domain,the method also developed over the years,the time domain finite element method(TDFEM).Time domain finite element method and frequency domain finite element method of solving process is similar.TDFEM compared with FEM,much to the discrete time process,namely the method not only have to be discrete about space,also want to discrete time.TDFEM can simulation for complex geometry structure model,and through the calculation results are discrete Fourier transform and wide-band characteristics is obtained.TDFEM can effectively solve the finite difference time domain method(FDTD)modeling for complex geometry structure of limitations,and compared with the FEM through a solution can get target wideband characteristics.This article embarks from the theory of finite element method,using the FEM calculation to solve the eigenvalue problem of cavity and rectangular waveguide electromagnetic transmission problems.In the process of programming realization of this method,because matrix dimension is bigger,by sparse storage to storage and operation can reduce the computational memory and improve the computational efficiency.To midfield space visualization,in this paper,by combing the VTK and Vis It drew the three-dimensional structure of a cloud.On the basis of research on FEM,the time domain finite element method theory formula is deduced,and through a numerical example to verify the method.A numerical example of the concrete content includes:1.By the time domain finite element method to complete the analysis of the eigenvalue problem of cavity.Zero minimum model in cavity central is calculated the results of the field changes over time.2.By the time domain finite element method for the calculation of distribution of rectangular waveguide midfielder.Absorbing boundary conditions on the waveguide is adopted to improve the boundary truncation,plus incentive source on surface of the port,calculate the rectangular waveguide midfielder changes over time,CST with computing field visualization of simulation results were compared and the electromagnetic transmission characteristics of rectangular waveguide is analyzed.3.The absorbing boundary conditions on the waveguide is a shot to truncation on the basis of the port,and perfectly matched layer(PML)boundary condition is used to instead of absorbing boundary conditions.TDFEM computing field visualization and CST,comparing the simulation results and results and absorbing boundary conditions on the waveguide truncation,comparing the calculation results by analyzing the predominance of PML condition truncation boundary.4.Through the way of adding Gaussian pulse source,using the TDFEM complete calculation to solve the rectangular waveguide and rectangular window of the structure of the wideband electromagnetic transmission characteristics.