The Influence of Mesh Granularity on the Accuracy of FEM Modelling of the Resonant State in a Microwave Chamber

Abstract

Microwave technology is widely used in different areas of advanced industry when energy must be provided to water-containing and other materials. The main barrier in the development of microwave devices is the possibility of efficient design by modelling a microwave system in a resonant state. For technical systems, the finite element method is widely used. However, the convergence process in the microwave finite element solver is sophisticated. The process itself and the influence of mesh granularity on the accuracy of modelling of microwave chambers in resonant states have not been investigated previously. The present paper aims to fill this gap. The resonance conditions of a microwave chamber were tested from the point of view of spatial resolution of the tetrahedral mesh used for open-source ELMER FEM software. The presented results experimentally determine the limits of accuracy of the geometry of microwave resonant chamber finite element method-based models. The determined values of microwave resonant chamber dimension tolerances should be considered for both open-source and commercial software for microwave modelling.

Improved Control of Mesh Density in Adaptive Tetrahedral Meshes for Finite Element Modeling

“…The finite element method (FEM) is widely used for modeling solid-state mechanics [4], flow [3], and magnetodynamic systems, including microwave [9] and magnetoinductive [7] systems. Recently developed open-source FEM-based toolchains give the unprecedented possibility of flexible modeling and development of advanced and sophisticated systems, such as eddy current tomography [8], resistive tomography [6,11], or airplane mechanics optimization [13].…”

“…On the other hand, the essential tool for efficient and robust FEM-based models is a meshing algorithm. Despite the fact that uniform grids are the most efficient from a physical point of view [12], such a meshing strategy leads to a radical increase in the number of elements [9]. As a result, adaptive meshes that utilize first-order tetrahedral elements are commonly used.…”