I have selected a small net from my board and extracted the S-Parameter model in post-layout (boardsim). I modeled it in linesim with exactly the same stackup. The net is very simple, i modeled it with a bunch of transmission lines assigned to the same layer (top in this case) with the exact same lengths and widths. The characteristic impedances are the same in both boardsim and linesim for all modeled lines.
The S-Parameter models diverge for frequencies above 1GHz and i can't understand why. Aren't the results suppose to be the same? I have re-checked everything.