A hybrid Crank-Nicolson FDTD subgridding boundary condition for lossy thin-layer modelling

TY - JOUR

T1 - A hybrid Crank-Nicolson FDTD subgridding boundary condition for lossy thin-layer modelling

AU - Cabello, Miguel

AU - Angulo, Luis

AU - Alvarez, Jesus

AU - Flintoft, Ian David

AU - Bourke, Samuel Anthony

AU - Dawson, John Frederick

AU - Garcia, Salvador

N1 - © 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

PY - 2017/5

Y1 - 2017/5

N2 - 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 computational 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.

AB - 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 computational 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.

KW - Finite-Difference Time Domain (FDTD), subcell models, thin layers, Crank-Nicolson, hybrid implicit-explicit (HIE), Carbon fiber composite, Electromagnetic shielding, Lossy materials

U2 - 10.1109/TMTT.2016.2637348

DO - 10.1109/TMTT.2016.2637348

M3 - Article

SN - 0018-9480

VL - 65

SP - 1397

EP - 1405

JO - IEEE Transactions on Microwave Theory and Techniques

JF - IEEE Transactions on Microwave Theory and Techniques

IS - 5

ER -