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    Looking for SPICE model for coupled lossy transmission line

    Looking for SPICE model for coupled lossy transmission line.
    This would have to work in standard berkeley spice-based simulators without special keywords specific to Altium or LTSPICE.
    It has to be lossy, with dissipation factor, or with dB/in.
    It has to be coupled, aka differential pair, with even and odd mode impedance.
    Is there a free spice model file that I can download, or someone can paste in here in a comment?

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    Re: Looking for SPICE model for coupled lossy transmission line




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    Re: Looking for SPICE model for coupled lossy transmission line

    I'd be happy to find just one tline .model that seemed credible.



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    Re: Looking for SPICE model for coupled lossy transmission line

    Quote Originally Posted by dick_freebird View Post
    I'd be happy to find just one tline .model that seemed credible.
    ”TLINE” is lossless model.
    So I don’t think it is possible with Berkeley Spice.



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    Re: Looking for SPICE model for coupled lossy transmission line

    The question is less clear than it may seem at first sight. You can easily make a LGRC lumped transmission line model, also coupled lines can be modelled by combining multiple transmission line models.

    But LGRC model doesn't represent a lossy line with realistic behavior, except for small band, which is a more or less trivial problem. So I would ask first about the purpose of your simulation.



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    Re: Looking for SPICE model for coupled lossy transmission line

    The purpose is high speed channel simulation with QUCS, to generate S-parameters.
    The frequency dependent loss and the tline delay are important.



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    Re: Looking for SPICE model for coupled lossy transmission line

    If you want a S-parameter model, why are you asking for a SPICE model? A simple behavioral model with constant delay and sqrt(f) proportional losses will fit a real transmission line much better than most lossy SPICE models.

    See previous discussions, e.g https://www.edaboard.com/showthread....for-long-Cable



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    Re: Looking for SPICE model for coupled lossy transmission line

    Quote Originally Posted by buenos View Post
    The purpose is high speed channel simulation with QUCS, to generate S-parameters.
    The frequency dependent loss and the tline delay are important.
    It's not that simple to replace missing models. The commercial simulators (e.g. ADS or Microwave Office) have a more complete model library.



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