Calculations of the electric field distribution in a TEM cell by the finite element method

This paper describes the use of the finite element method (FEM) to calculate the field distributions inside the cell. Quasi-static conditions are assumed, which consequently restrict the calculations to the frequencies below the cell´s cut-off frequency. The 2-dimensional Laplace equations are presented with the boundary conditions applied. Then, the FEM method is used to solve the equations to get the field distributions. The 3-dimensional structure has been modelled by two 2-dimensional calculations. This has simplified the complexity of the programming and at the same time achieved our purpose. The final field strength is approximated by the combination of these two 2-dimensional calculations.