| Abstract: |
In recent years, as the performance of computers and parallel computing technology has improved, electromagnetic field simulation has also seen further evolution, including analysis functions for large spaces. Along with this evolution, demand for the use of electromagnetic field analysis is increasing, not only in conventional industrial applications but also in medical settings, to improve the safety of medical devices such as microwave scalpels. Among electromagnetic field analyses for high-frequency regions, the mainstream method is a formulation that solves a vector wave equation with the electric field E as an unknown function. To express the electric field waveform, which is the solution obtained by analysis, with low error, it is necessary to divide the process into elements whose maximum side length is 1/10 to 1/20 of the wavelength, which greatly increases the computational scale. Therefore, the authors’ research group is researching and developing a finite edge element full-wave electromagnetic field analysis method based on the domain division method, which is known to be effective for large-scale analysis. Parallelization is essential for large-scale analysis, and this study applies one method, the iterative domain decomposition method. In this method, the analysis domain is divided into small domains called subdomains, and while finite element analysis is performed for each subdomain, an interface problem is solved to satisfy the equilibrium problem between domains. For subdomain problems, highly efficient parallel computation is possible because the subdomain problems can be calculated independently by applying Gaussian elimination, which is a direct method, and an iterative method between subdomain boundaries. As a method for implementing the iterative domain decomposition method (IDDM) on a parallel computer, the hierarchical domain decomposition method (HDDM) with two levels of hierarchy is applied. The effectiveness of this method in large-scale analysis of high-frequency electromagnetic field problems has been reported in past studies. In this study, first, a resonator model was used to determine the appropriate convergence criterion in the gigahertz region for the matrix iterative solution of the analysis code. Next, by adding the necessary functions for large-scale analysis, such as mesh subdivision using a domain decomposition type data structure, we built a large-scale full-wave electromagnetic field analysis framework that can be applied to the electromagnetic compatibility (EMC) study of large medical electromagnetic environments, such as operating rooms where microwave scalpels are used. |