Domain Decomposition-Based DGTD Method With Automated Implicit--Explicit Classification for Multiscale Electromagnetic Modeling

In this article, an efficient domain decomposition-based discontinuous Galerkin time-domain (DGTD) method with automated implicit–explicit classification is proposed to facilitate the modeling of large-scale and multiscale electromagnetic problems. By adopting an operating-wavelength-based domain decomposition strategy, the computational domain can be automatically partitioned into multiple nonoverlapping explicit and implicit subdomains for arbitrary geometries. Specifically, electrically small structures containing elements with edge lengths much smaller than the operating wavelength are isolated and solved by the implicit time integration scheme, whereas subdomains dominated by large-scale features and discretized using coarse meshes with relatively large edge lengths are treated explicitly. This automated domain decomposition, together with the corresponding implicit–explicit time integration scheme, eliminates the need for carefully prescribed subdomain partitioning and substantially enhances the flexibility of the subdomain-level DGTD method for complex electromagnetic problems. Several representative numerical examples are presented and discussed to demonstrate the computational efficiency and flexibility of the proposed method with respect to the conventional DGTD schemes.