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The FVTD working group is
a part of the "Laboratory for Electromagnetic Fields and
Microwave Electronics (IFH)" at
the ETH Zurich. Since the end
of 2001 a 3D electromagnetic field solver is developed using
the Finite-Volume Time-Domain method.
The FVTD method is applied to the numerical
solution of Maxwell's equations since the end of the 1980's.
A great advantage of FVTD is its ability to be applied in unstructured
meshes. Therefore, FVTD constitutes a powerful alternative to
the Finite-Difference Time-Domain (FDTD) method for electromagnetic
problems where conformal meshing is advantageous, i.e. for structures
that include curved and oblique surfaces or large dielectric
contrasts (e.g. dielectric resonator antenna).
Another type of geometries that still constitute a challenge
for time domain methods are those in which fine structural details
compared to the wavelength are in close proximity to large structures
(e.g. double-ridged horn antenna).
The discretization of such structures with 3D regular Cartesian
grids results in prohibitively high computational costs. Using
an unstructured mesh permits to adapt locally the cell dimensions
to the size of the geometrical features, therefore avoiding a
3D explosion of the number of cells. The transition between the
regions with different cell densities is smooth in nature. However,
the drawback that still remains is that the required time step
for stability is determined by the smallest cell in the entire
mesh. To overcome this problem for the FVTD method, we propose
a generalized scheme of local time
steps in an unstructured mesh.
The inhomogeneous mesh used in FVTD, consisting
of triangles and tetrahedrons, is generated with the commercial
software Altair® HyperMesh®
Please address questions and comments to the working
group members or write an email.
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