Graphene-based devices constitute a pioneering field of research for their extraordinary electromagnetic properties. The incorporation of appropriate models into numerical simulators is necessary in order to take advantage of these properties. In this work, we propose a method to incorporate graphene-sheet models into the FDTD method. The use of vector-fitting techniques expands the permittivity of graphene into a rational function series of complex conjugate pole-residue pairs, which is implemented into FDTD by an auxiliary differential equation formulation. Simple waveguiding problems validate our approach.

The simulation of highly resonant structures requires techniques that are accurate and free of spurious-mode contamination. Spurious modes can severely corrupt the solution of a physical problem, and their suppression is a must for any numerical scheme in the frequency or in the time domain (TD). In this paper, we present the application of a highly accurate spurious-free vector discontinuous Galerkin TD method to waveguide applications. We show that spurious solutions (which increase with the number of degrees of freedom of the problem) can be efficiently attenuated by using penalized fluxes. For validation, we apply our approach to the simulation of microwave filters since their highly resonant behavior is challenging for TD techniques.

We summarize the boundary and source implementation for the several formulations of the discontinuous Galerkin time domain method (DGTD). Since DGTD with zeroth-order scalar basis functions using the upwind flux, coincides with the finite volume time domain (FVTD), many of the concepts developed for FVTD can be ported to DGTD in any of its different formulations (scalar/vector basis, upwind/centered flux). Numerical examples illustrate the different alternatives.

Discontinuous Galerkin, applied to time-dependent Maxwell equations (DGTD), offers attractive properties when compared to other numerical methods. This method is flexible and accurate, like the finite element method, and efficient as well as scalable like finite-difference time-domain algorithms. In this letter, a new rigorous treatment of anisotropic materials in three dimensions is described and validated for the upwind-flux DGTD method.

The increased use of carbon-fiber composites in unmanned aerial vehicles is a challenge for their EMC assessment by numerical solvers. For accurate and reliable simulations, numerical procedures should be tested not only for individual components, but also within the framework of complete systems. With this aim, this paper presents a benchmark test case based on experimental measurements coming from direct-current injection tests in the SIVA unmanned air vehicle, reproduced by a numerical finite-difference-time-domain solver that employs a new subgridding scheme to treat lossy composite thin panels. Validation was undertaken by applying the feature selective validation method, which quantifies the agreement between experimental and numerical data.

A novel conformal technique for the FDTD method, here referred to as Conformal Relaxed Dey-Mittra method, is proposed and assessed in this letter. This technique helps avoid local time-step restrictions caused by irregular cells, thereby improving the global stability criterion of the original Dey-Mittra method. The approach retains a second-order spatial convergence. A numerical experiment based on the NASA almond has been chosen to show the improvement in accuracy and computational performance of the proposed method.