Question: Is the "loss tangent" parameter in the
substrate definition defined in its classical sense?
For example, I used 0.018 for FR4 and that seems to
wipe out all the resonance peaks above 100 MHz or so.
Is this right? Is this "loss tangent" which you also
refer to as "rho" related to the "actual" loss tangent
by some other factor?
Loizos Vakanas, PhD
Signal Integrity Engineer
Cisco Systems, San Jose, CA