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Q&A on Electromagnetic Analysis

Q: Which boundary condition is suitable for the outer boundary?

A:

The default setting is "magnetic wall", but it should be changed depending on the analysis model.
"Electric wall" is suitable for shielded models such as waveguides. For other cases, "open boundary" will be more suitable.
Note that "open boundary" usually requires longer calculation time and more memory than "electric wall" since the loss of radiation is taken into account.

Q: Is there any criterion for the size of the air domain?

A:

The air domain is not needed for all cases. It is required when analyzing the electromagnetic waves propagating in air, e.g. antenna.
These is no clear criterion for the size of the air domain, but allowing about 1/4 of the wavelength between the model and the open boundary usually yields reasonable results.

There will be cases where the electromagnetic waves leak to the surrounding atmosphere. In such cases, create the air domain around the model.

Q: Is it possible to create ports inside the model?

A:

Yes. For example, a port is created inside the dipole antenna below.
There are two ways to create a port for this model:
1. Create a face between the upper and the lower conductors. Set the port boundary condition on this face.
2. Create a box between the upper and the lower conductors. Set the port boundary condition on a face of the box.
Either way is OK.