A hybrid Crank-Nicolson FDTD subgridding boundary condition for lossy thin-layer modeling Ruiz Cabello, Miguel Díaz Angulo, Luis Manuel Alvarez Gonzalez, Jesus Flintoft, Ian Bourke, Samuel Dawson, John Gómez Martín, Rafael Antonio González García, Salvador Finite-Difference Time Domain Subcell models Thin layer Crank-Nicolson Hybrid implicit-explicit Carbon fiber composite Electromagnetic shielding Lossy materials The inclusion of thin lossy, material layers, such as carbon based composites, is essential for many practical applications modeling the propagation of electromagnetic energy through composite structures such as those found in vehicles and electronic equipment enclosures. Many existing schemes suffer problems of late time instability, inaccuracy at low frequency, and/or large computational costs. This work presents a novel technique for the modeling of thin-layer lossy materials in FDTD schemes which overcomes the instability problem at low computational cost. For this, a 1D-subgrid is used for the spatial discretization of the thin layer material. To overcome the additional time-step constraint posed by the reduction in the spatial cell size, a Crank-Nicolson time-integration scheme is used locally in the subgridded zone, and hybridized with the usual 3D Yee-FDTD method, which is used for the rest of the compu- tational domain. Several numerical experiments demonstrating the accuracy of this approach are shown and discussed. Results comparing the proposed technique with classical alternatives based on impedance boundary condition approaches are also presented. The new technique is shown to have better accuracy at low frequencies, and late time stability than existing techniques with low computational cost. 2018-04-13T11:52:43Z 2018-04-13T11:52:43Z 2017 journal article Ruiz Cabello, M. ; et. al. A hybrid Crank-Nicolson FDTD subgridding boundary condition for lossy thin-layer modeling. IEEE Transactions on Microwave Theory and Techniques, Volume: 65, Issue: 5, pp. 1397 - 1406, May 2017 [http://hdl.handle.net/10481/50214] http://hdl.handle.net/10481/50214 10.1109/TMTT.2016.2637348 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License