S-parameters passivity problems

Hi all,
I want to know why there is a option for "PASSIVITY ", given in many tools for s-parameters, but this is not present for R,L and C. Are extracted s-parameters of PCB traces, form a non-passive model. Many simulator have this option. Please Help.

The RLGC transmission line model is so trivial that you can see and fix negative resistances.

Hi,

I don't know if this is relevant for your purposes. There are conditions that must be satisfied by any passive network:
If it is described by lumped R, L and C, all componentents must have positive values.
But very often an n-port is characterized by s parameters. Then, this condition holds at any frequency:

|s_1i|² + |s_2i|² + ... + |s_ni|² ≦1 for any i=1,...,n

Regards

Z

The s-parameters are extracted of a PCB trace. which is a passive network. Then why using this s-parameters file tool needs to define the passivity value. so that simulation may converge.

---------- Post added at 21:47 ---------- Previous post was at 21:45 ----------

The s-parameters are extracted of a PCB trace. which is a passive network. Then why using this s-parameters file tool needs to define the passivity value. so that simulation may converge.

Please provide your feedback. It is very urgent.

Thanks