some questions about using CST MWS 5.0, thank you!

I am a beginner of CST MWS 5.0, i have three questions to ask, any help will be appreciated!

1 what is ?surrounding space?, when should we expand the model to get extra space for computation (set lower/upper distance)? which material is filled in the extra space? the background material?

2 It seems that ?bounding box? is set by the program itself. Can we control its size? Is bounding box the only domain which will be analyzed to obtain the result? Are boundary conditions put on the faces of the bounding box?

3 when to set magnetic symmetry plane ? Ht=0? I often see the symmetry plane of a structure under investigation is set to a magnetic symmetry plane ? is there some relationship between them?

Best regards!

you should read first the documentation of CST MWS 5.0.

1. Additional surrounding space needs to correct simulate antennas problems. It is filled the background material. See the 'Open/Add space' boundary conditions in manual.
2. The bounding box size is overall dimension+additional space in first question.
3. Magnetic symmetry plane means that it is:
a) geometrical symmetry plane of structure
b) tangential component of magnetic field on this plane Ht=0
An example of this plane is plane passing through the center of rectangular waveguide and parallel to broad wall of waveguide (for H10 mode).

Regards,
Kit