Important Applications on the TF/SF Source and Grid Proportion for Explicit–Implicit Hybridizable Discontinuous Galerkin Time-Domain Method

Based on our previous research on the explicit-implicit hybridizable discontinuous Galerkin time-domain (ex-imHDGTD) method, this letter gives two important applications in time-domain multiscale electromagnetics. The first is that the different ratios of both coarse and refined meshes are discussed, which shows that grid division strategy has a significant effect on the performance of ex-imHDGTD. The second is that a total-field/scattered-field (TF/SF) method is derived to impose the excitation on interfaces instead of boundary faces. Compared with the traditional hybridizable discontinuous Galerkin (HDG) method, the introduction of TF/SF changes the formulations of both local and global linear systems. Once applying this TF/SF in ex-imHDGTD, it is very easy for 3-D waveguide problems to obtain the transmitted and reflected waves. Note that this is the first time the TF/SF is used in the ex-imHDGTD method. Numerical results show that the proposed applications are feasible due to higher computational performances.