Learning Forum

[Philipp del Hougne]

I would like to compare two simulations that only differ regarding the fact that lumped ports are replaced by lumped elements with a certain load impedance. However, currently, I get slightly different results (in terms of the S-matrix between the wave ports at 50 Ohms) with the two approaches.

It seems that the mesh is slightly different in the two cases, maybe that is the origin of the problem, but it appears impossible to import the same mesh in both cases due to supposedly different geometries of the model (but I don’t see why they would be different). 

Is it possible to use the same mesh for both cases?

[Faezeh Ladani]

Hi Philipp,

It is expected to see different mesh when you replace the lumped ports by lumped elements. Now, by lumped elements, do you mean you have used circuit elements inside HFSS design? Or did you use Lumped RLC boundaries? 

If you use the latter, you should be able to import the mesh from Lumped port model since you can keep the geometry of both designs identical. This is the only criteria you need to import mesh. (By the way, if you have not used the feature before, read about it in the HFSS Help).

Also, if you are renormalizing lumped ports to some imaginary values, use Power definition for S parameters instead of Generalized which is the default. To set that, from menu go to HFSS> Design Settings...> S Parameters.