SMIET does not work on vxB axis

Due to the "simplistic" decoupling approach, there is no reasonable signal in antennas on the vxB axis. There are strategies to deal with this, but the user should be allowed to choose which one they want to use. Therefore, an approach where this limitation is clearly stated in the documentation, together with some example scripts on how to deal with this issue, is probably the best approach.

What definitely needs to happen though, is to set the E-fields on the vxB axis to 0, instead of returning the crazy traces that result from synthesis.