Slab waveguide excitation
I am trying to simulate a simple case of 1D slab wave guide. The problem is that I could not figure out which excitation to use. I already tried a waveport with large dimension. However, I noticed that all the modes the program solved for were nearly the closed rectangular wave guide modes and not the slab waveguide modes.
Could anyone help me please.
That's because the waveguide excitation calculates the modes for a rectangular waveguide with those LxW and dielectric constant of the medium. As long as the mode's cut off is below the cutoff of your waveguide it WILL propagate.
Thanks for replay
It is indeed similar to the rectangular waveguide mode as confirmed by the field configuration. However, there is still the question. How to excite the 1-D slab waveguide modes?
Set a periodic boundary condition (master/slave) so that the model is effectively infinite in one transverse direction. Then, choose an appropriate excitation.
Waveports are not appropriate because they force the fields to be zero at all their boundaries. (For microstrip/CPW this does not matter, as long as the waveport is big enough that fringing fields at the waveport boundary are negligible, but for a slab waveguide, fields at the boundary are significant.) In HFSS 11 or higher, I think a Floquet Port is best for this situation. In HFSS 10, a combination of "Incident Plane Wave" excitation and Radiation boundary with "Reference for FSS" option might work.