@article{Пільтяй_Булашенко_Гергіль_2021, title={Numerical Performance of FEM and FDTD Methods for the Simulation of Waveguide Polarizers}, url={http://radap.kpi.ua/radiotechnique/article/view/1685}, DOI={10.20535/RADAP.2021.84.11-21}, abstractNote={<p>Nowadays, method of finite differences (FDTD) is most frequently applied for the numerical simulation of the processes of electromagnetic waves propagation in various microwave devices and antenna systems in the time domain, while in the frequency domain the finite elements method (FEM) is the most used one. Therefore, the comparison of these effective modern calculation methods is an urgent problem. Currently, there are many modifications of these numerical methods, which possess their own strengths and weaknesses. This article presents the results of the analysis and comparison of these two methods on the example of modeling of the electromagnetic characteristics of a polarizer based on a square waveguide with five irises. As a result, it was found that the convergence of the voltage standing wave ratio of the developed polarizer is fast for both methods. In addition, it was obtained that the convergence of the characteristics of differential phase shift, axial ratio and crosspolar discrimination of the developed microwave device are much more sensitive to the number of applied mesh cells. This number of mesh cells was obtained by the adaptive dividing of the inner structure’s volume of the device. It was found that it is necessary to use not less than 120 000 cells of the adaptive tetrahedral mesh on the whole volume of the polarizer’s structure in the case of finite elements method in the frequency domain utilization with the required accuracy of calculation of the polarization characteristics of the developed waveguide polarizer with irises, which is equal to 0.2 dB. It was obtained that it is required to use not less than 1 200 000 cells of the hexahedral mesh on the whole volume of the polarizer’s structure in the case of finite difference time domain method application with the required accuracy of calculation of the polarization characteristics of the developed waveguide polarizer with irises, which is equal to 0.2 dB. In addition, in the article we have revealed that the computation time of the finite difference time domain method is more than 2 times longer than the corresponding time required for the calculation using finite elements method in the frequency domain. In this case the corresponding number of hexahedral mesh cells in the finite difference time domain method is 10 times greater than the number of tetrahedral mesh cells required in the finite elements method in the frequency domain. </p>}, number={84}, journal={Visnyk NTUU KPI Seriia - Radiotekhnika Radioaparatobuduvannia}, author={Пільтяй, С. І. and Булашенко, А. В. and Гергіль , Є. Є.}, year={2021}, month={Mar.}, pages={11-21} }