Many times it makes sense to use the FDTD solver that is available as part of the standard FEKO installation. For example:
- You need many frequency points.
- You have many dielectric layers included in your geometry.
- There are few curved lines or surfaces in your geometry.
- Your graphics card is fast.
That said, solver convergence can be difficult even with a valid mesh. Here are a few tips that may help speed up the process:
- When you have small features or curved surfaces in your model, use local mesh definitions on lines and surfaces that are small relative to the rest of the model. This helps ensure the mesh more closely matches the geometry, reducing the likelihood of mesh errors and problems.
- If you have the memory available, set the solver to use double precision memory storage, which will almost always lead to solution convergence.
If you still are having problems after implementing the tips above, then:
- Increase the total time interval of the solution. Search for the string “Total time interval” in the OUT file. Note the number of seconds being used by the solver. In CADFEKO open up the frequency dialog. On the advanced tab, check “Specify time interval in seconds,” and enter the total time interval multiplied by a factor of 10. Any number larger than the base number you copied may lead to convergence, but multiplying by 10 is a good starting point. Just be prepared to use a larger number.
- If you are using a wire feed, try using an edge feed. If using an edge feed try using a wire feed.
- If using a wire feed, set the wire radius to the value best suited for the voxel mesh element using the “Use intrinsic wire radius” setting on the Create Mesh dialog.
There are undoubtedly other tips that may lead to solver convergence, but I have found this to be the best approach.
ARSI 