A New Efficient and Stable 3D Conformal FDTD

Abstract

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.

Errors in the shielding effectiveness of cavities due to stair-cased meshing in FDTD: Application of empirical correction factors

“…Fig. 8 shows a comparison of the SE at the centre of the sphere using the corrected thin layer model and the original thin layer model, there is also a comparison to a conformal FDTD model [13]. It can be seen that the correction factor has improved the magnitude of the SE considerably, with reduction in the error from approximately 3 dB to less than 1 dB.…”

Face-Centered Anisotropic Surface Impedance Boundary Conditions in FDTD

“…In this case the shell material is a 1-mm-thick conductive sheet with a conductivity of 1 kS/m. The new face-centered approach is compared to the usual edge-based approach implemented in the University of Granada FDTD code, and also to results found with a conformal SIBC approach, based on the combination of the SIBC technique of [11] and the conformal method of [15]. The results for the edge-centered case show an error of about 6 dB around the first resonance, whereas the face-centered approach shows an error of about 3 dB.…”

“…Careful treatment of the intersection of SIBC faces is necessary in order to resolve the inherent ambiguity of the surface normal on stair-cased edges when curved surfaces are approximated on a structured mesh. Conformal algorithms have been developed [13]- [15]; however, these techniques are more computationally expensive and a tradeoff between efficiency and accuracy must be considered for their particular application.…”

Face centered anisotropic surface impedance boundary conditions in FDTD: Improved performance of staircased mesh for shielding problems

“…The new face centered approach is compared to the usual edge based approach implemented in [11] and also to results found with a conformal SIBC approach, based on the combination of the SIBC technique of [ [12]] and the conformal method of [13] in Fig. 4.…”

“…Careful treatment of the intersection of SIBC faces is necessary in order to resolve the inherent ambiguity of the surface normal on stair-cased edges when curved surfaces are approximated on a structured mesh. Conformal algorithms have also been developed [4], [5], however, these techniques are more computationally expensive and a trade-off between efficiency and accuracy must be considered for any particular application.…”