Face-Centered Anisotropic Surface Impedance Boundary Conditions in FDTD Flintoft, Ian Bourke, Samuel Dawson, John Alvarez Gonzalez, Jesus Ruiz Cabello, Miguel Robinson, M. P. González García, Salvador Finite-difference time domain Impedance network boundary condition Surface-impedance boundary condition This paper is an expanded version from the IEEE MTT-S International Symposium Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave and Teraherz Applications, May 17–19, 2017, Seville, Spain Thin-sheet models are essential to allow shielding effectiveness of composite enclosures and vehicles to be modeled. Thin dispersive sheets are often modeled using surface-impedance models in finite-difference time-domain (FDTD) codes in order to deal efficiently with the multiscale nature of the overall structure. Such boundary conditions must be applied to collocated tangen- tial electric and magnetic fields on either side of the surface; this is usually done on the edges of the FDTD mesh cells at the electric field sampling points. However, these edge-based schemes are difficult to implement accurately on stair-cased surfaces. Here, we present a novel face-centered approach to the collocation of the fields for the application of the boundary condition. This approach naturally deals with the ambiguities in the surface normal that arise at the edges on stair-cased surfaces, allowing a simpler implementation. The accuracy of the new scheme is compared to edge-based and conformal approaches using both planar sheet and spherical shell canonical test cases. Staircasing effects are quantified and the new face-centered scheme is shown have up to 3-dB lower error than the edge-based approach in the cases considered, without the complexity and computational cost of conformal techniques. 2018-04-16T08:03:28Z 2018-04-16T08:03:28Z 2018 info:eu-repo/semantics/article Flintoft, Ian; et. al. Face-Centered Anisotropic Surface Impedance Boundary Conditions in FDTD. IEEE Transactions on Microwave Theory and Techniques, vol. 66, no. 2, pp. 643-650, Feb. 2018 [http://hdl.handle.net/10481/50236] http://hdl.handle.net/10481/50236 10.1109/TMTT.2017.2778059 eng info:eu-repo/grantAgreement/EC/FP7/205294 http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License IEEE