momentum question

hello, im trying to model a SI-LPF with momentum, but i dont know which of the substrate layer model (photo in attachement) to use. The substrate is Nelco N9000 if it helps...
Thank you

If u know the Substrate details enter those substrate layer details and in layout layer use it as substrate.

i know all the substrate parameters, and it seems correct to use sheet conductor.
Can you explain what 'thick,expanion up' and 'thick,expansion down' means?
are they used to define multilayer substrates?

By default, Momentum will simulate the conductors with an infinitely thin metal sheet. Metal losses are included by mapping the corresponding surface impedance onto the sheet.

In many cases, this "thin metal" approach is good enough. However, if the thickness of the metal changes the field distribution, you want to include that thickness in the EM model ("thick metal").

With expansion up/down, you can choose if the thick metal will go up or down. Depending on the direction that you choose, Momentum will add in a dielectric sheet which inherits the material properties from the dielectric above/below. This is the dielectric which is defined "on the side" of the thick metal. The effective distance to the metal layers above and below will remain unchanged, and Momentum adds this additional dielectric behind the scenes.

Best regards
Volker

PS: If you use the Sonnet EM simulator, the thick metal expansion works differently. Here, the thick metal will always penerate into the dielectric above, and the user must adjust the stackup manually. Both methods have their advantage and disadvantage.