Symmetry planes in electromagnetic simulation

Hi, Im simulating an antenna with CST, in the model I used a magnetic symmetry plane which has worked great!..... I would like some theory or comments on the type of symmetry plane (magnetic), I know it means that the tangential magnetic field is zero, but why is this the correct type of symmetry?? ......... basically Im asking for a critereon on selecting the type of symmetry and some theory if possibble.........thanks......

When the tangential electric field is zero, the boundary is electric wall.
Same to the magnetic wall. In cst or HFSS,the Symmetry planes are provided. But whether the wall is electric or magnetic wall,it is based on practice!!!

the correct selection of the symmetry plane (electric, magnetic or non) depends on two criteria. The first one is obvious: the structure has to be symmetric. If this is the case, you can use symmetry planes in general but is does not tell you which one is the correct one.

The second criteria is, that the used excitation has to be symmetric as well.
Just create a simple waveguide, define a WG-Port and solve for the port modes for different symmetry settings (non, magnetic, electric). To make it more clear you should include not only the fundamental mode but also a few higher order modes in the calculation. As you can see, CST MWS calculates different mode patters depending on the selected symmetry plane.

Before you select any symmetry plane in your calculation just have a look at the feed. How does the field pattern look like for your feed? This tells you which symmetry plane is correct.

Hope this helps,

F.