@misc{10481/109392,
year = {2025},
month = {12},
url = {https://hdl.handle.net/10481/109392},
abstract = {Accuracy is a key aspect to be considered when
assessing results from subgridding algorithms in the finitedifference time-domain (FDTD) method. This work focuses on
the accuracy of a newly developed orthogonalized integralbased subgridding (OI-SG) algorithm and is divided into two
main parts. First, we identify and quantify spurious reflections
present in OI-SG by considering a set of free-space simulations
containing a subgridded region illuminated by a plane wave and
measuring the (spurious) far-field scattering. We find that the
most relevant parameter of merit in these cases is the points-perwavelength (PPW) criterion used for the spatial discretization.
Second, we study near-field effects produced by the interaction
between material objects and subgridding interlevel boundaries.
We observe that the PPW criterion is not sufficient to determine
accuracy in these cases. We find out that an important role is also
played by the buffering distance between the subgrid boundaries
and the material objects. We consider a variety of application
examples in our analysis: a frequency selective surface (FSS), an
all-angle negative refraction (AANR) metasurface, a conducting
sphere, and a NASA almond. In all cases, we measure the error
as a function of the spacing between the objects and the lowest
level subgridding boundary (buffering distance). We observe
significant accuracy improvements in all cases},
publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
title = {Analysis and Mitigation of Discretization Errors in the Orthogonalized Integral-Based Subgridding FDTD Algorithm},
doi = {10.1109/tap.2025.3617134},
author = {Martín Valverde, Antonio Jesús and Teixeira, Fernando L. and Ruiz-Cabello Núñez, Miguel David},
}