#15 Loss tangent discrepancy...

Version_3
open
Eugene Jansen
Models (4)
5
2002-11-17
2002-11-13
Anonymous
No

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?

thanks

Loizos Vakanas, PhD
Signal Integrity Engineer
Cisco Systems, San Jose, CA
408-853-2505

Discussion

  • Eugene Jansen
    Eugene Jansen
    2002-11-17

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    Hi ,

    The loss tangent parameter is used in its classical sense i.e.
    what is commonly provided as a dielectric loss specification
    by substrate manufacturers. The "rho" is actually a historical
    reference to the parameter used in the HP Touchstone
    software (now Agilent EEsof) and may cause some
    confusion. Note that "rho" as used by Touchstone implied tan
    (rho), which is indeed the dielectric loss tangent.

    It would make it easier to investigate the issue if you could
    provide us with the circuit you've used.

    Cheers,
    Eugene

     
  • Eugene Jansen
    Eugene Jansen
    2002-11-17

    • labels: 105954 --> Models
    • milestone: --> Version_3
    • assigned_to: nobody --> eugenejansen