XTK from Quad Design/Viewlogic should meet your needs here, at least in the
"low-loss" regime where the skin effect resistance is less than 50% of the
characteristic impedance of the line. XTK is a time domain transmission line
simulator that accepts IBIS models, allows user-controllable data patterns,
and has frequency-dependent skin effect loss models for both the resistive
and inductive effects. Future releases will extend the regime of applicability
to higher loss regimes, but the current models apply to many cases of
practical interest, and perhaps yours. Dielectric loss is also modelled,
with a constant "loss-tangent" model.
Larry Rubin
Viewlogic Advanced Development Group
(Quad Design)
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