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impedance of a RLGC defined mtline is not conjugate at postive/negative frequency in PSP shooting simulation

Hubertastra

Dear Sir/Madam

I'm using virtuoso ic618hf with spectre 191hf.

I'm trying to simulate the input admittance of a open-loaded loss-less transmission line (using mtline from analogLib with the RLGC form ).

Due to my perfonal application, I need to check its admittance at both postive/negative frequency using PSP (e.g. +20GHz and -20GHz).

When I used Harmonic Balance engine for PSS, the results of PSP at postive & negative frequency are indeed conjugate. However, when I use shooting engine. the admittance at both positive and negative frequency are the same (both real and imaginary part).

Since there are some square-wave LOs in my circuit, shooting should be much faster and more accurate if this problem can be solved.

Any comment is welcomed.

Best regards,

Yang

Parents

  • Yang,

    My assumption is that the per-frequency RLGC matrices are non-physical and so when modelling that in the time domain the fit is not very good. Determining what the problem is without data is going to be difficult, so I suggest you contact customer support so that you can provide a test case showing the problem .

    Regards,

    Andrew

  • in reply to Andrew Beckett

    Dear Andrew,

    Thank you for your quick reponse.

    Since I haven't contacted the customer support before, may I ask how to contact the customer support?

    Do I need to initial a case (it seems that only premium support can do so)? Or I just email to them?

    Thank you for your time and help.

    Best regards,

    Yang

  • in reply to Hubertastra

    Yang,

    Unless you are either an academic user or you have 99-year licenses and are not paying maintenance, you are entitled to support. You need to know the hostid of your license server to register (this is at the top of your license file). Once you've done that you can create a support case on the site. There's not really a concept of "premium support".

    If you're an academic user, then if part of the Europractice scheme, then you can contact Europractice for support (and if needed, they will contact us). For other academic institutions, then typically you need to get a case created by the link user for your institution.

    Regards,

    Andrew

  • in reply to Andrew Beckett

    Dear Hubertastra, 

    Two thoughts came to mind if you have the patience...

    1. Did you happen to compare the PSS solutions for your Harmonic Balance and Shooting analyses? If your stimuli is composed of square waves, it sounds as if your PSS setup will need to be significantly different for an accurate solution - especially with a lossless RLGC based transmission line. I am wondering how the two solutions compare.

    2. Have your tried adding some loss to your RLGC matrix and performing a Harmonic Balance and a Shooting based PSS analysis? I am wondering if your two admittance solutions will differ if some loss is introduced. As Andrew hinted, I am concerned about simulating a lossless transmission line with an ideal square waves with, potentially, infinite frequency content.

    If you are busy or do not believe either of these comments have merit, please do not feel obligated to comment Hubertastra!

    Shawn

Reply
  • in reply to Andrew Beckett

    Dear Hubertastra, 

    Two thoughts came to mind if you have the patience...

    1. Did you happen to compare the PSS solutions for your Harmonic Balance and Shooting analyses? If your stimuli is composed of square waves, it sounds as if your PSS setup will need to be significantly different for an accurate solution - especially with a lossless RLGC based transmission line. I am wondering how the two solutions compare.

    2. Have your tried adding some loss to your RLGC matrix and performing a Harmonic Balance and a Shooting based PSS analysis? I am wondering if your two admittance solutions will differ if some loss is introduced. As Andrew hinted, I am concerned about simulating a lossless transmission line with an ideal square waves with, potentially, infinite frequency content.

    If you are busy or do not believe either of these comments have merit, please do not feel obligated to comment Hubertastra!

    Shawn

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