A Conformal Thin Boundary Model for FDTD

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Thin layer models are widely used in the finitedifference time-domain (FDTD) technique to efficiently model
boundaries in multi-scale simulations as they significantly reduce
simulation run-times and memory requirements. These models
often utilise surface impedance boundary conditions (SIBCs) to
represent the material of the boundary. Conformal meshes are a
popular method of representing curved and non-aligned surfaces
in FDTD. These meshes deform cells in the FDTD grid around the
boundary between bulk materials so as to more accurately represent the shape of the material. Here we present an algorithm that combines the efficiency of a thin layer model with the accuracy of a conformal mesh. The algorithm is applied to three resonant cavity models and the accuracy verified using comparisons to non-conformal meshes and analytic solutions. Improvements are shown in the accuracy of the resonant frequencies and magnitude of the shielding effectiveness (SE) of the cavities. It is also shown to reduce the prevalence of extraneous features in the frequency response of the SE that are apparent when using a stair-cased mesh.
Original languageEnglish
Title of host publication2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO) (NEMO2018)
Number of pages4
ISBN (Electronic)9781538652046
Publication statusPublished - 8 Aug 2018

Bibliographical note

©2018 IEEE


  • Conformal Techniques
  • Finite-Difference Time-Domain
  • Surface-Impedance Boundary Condition
  • Thin Layer

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