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s2p -> ADS, calculate Z abnormal

Question asked by mems on Dec 10, 2017
Latest reply on Dec 12, 2017 by volker_muehlhaus

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s2p -> ADS, calculate Z abnormal, calculate Y & S normal. Why? Thanks!

Simulation / Synthesis Messages

Warning detected by hpeesofsim during SP analysis `SP1'.
The Z-parameter matrix does not exist because some or all of the Z-parameters are infinite. Setting all Z-parameters
to zero.
Warning detected by hpeesofsim during SP analysis `SP1'.
While evaluating `SNP1.CMP1.All':
The provided data file doesn't cover the requested value(s) of `freq'. Therefore the required data was obtained from extrapolation.
Warning detected by hpeesofsim during SP analysis `SP1'.
While evaluating `SNP1.CMP1.Z[1]':
The provided data file doesn't cover the requested value(s) of `freq'. Therefore the required data was obtained from extrapolation.

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Z.s2p.zip217.4 KB

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8 Replies

sdgrant Dec 11, 2017 12:11 AM
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Z parameters (Impedance parameters) provide a measure of the impedances through the different parts of the electrical network. S parameters provide measurements of voltage wave ratios through an electrical network. Using dB notation make sense for the S parameter ratios. However, it does not make sense for z parameters so these should never be expressed in dB.
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- mems @ sdgrant on Dec 11, 2017 1:10 AM
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  Thank you so much for your reply! The Y parameters are calculated from S parameters and Y parameters are normal in dB. Z parameters should be able to be converted from S parameters.
  Two-Port matrix conversions:
  http://qucs.sourceforge.net/tech/node98.html
  
  Simulation / Synthesis Messages
  Warning detected by hpeesofsim during SP analysis `SP1'.
  The Z-parameter matrix does not exist because some or all
  of the Z-parameters are infinite. Setting all Z-parameters
  to zero.
  Warning detected by hpeesofsim during SP analysis `SP1'.
  While evaluating `SNP1.CMP1.All':
  The provided data file doesn't cover the requested value(s) of `freq'. Therefore the required data was obtained from extrapolation.
  Warning detected by hpeesofsim during SP analysis `SP1'.
  While evaluating `SNP1.CMP1.Z[1]':
  The provided data file doesn't cover the requested value(s) of `freq'. Therefore the required data was obtained from extrapolation.
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- mems @ sdgrant on Dec 11, 2017 1:48 AM
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  Z parameters are also abnormal in magnitude.
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volker_muehlhaus Dec 11, 2017 4:41 AM
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Did you notice the warning "The provided data file doesn't cover the requested value(s) of `freq'. Therefore the required data was obtained from extrapolation"?
Don't trust extrapolated data, that can be completely wrong.

If the data is from measurement, use only the measured frequency range, or repeat the measurement with full frequency range.

Looking at the data and converting to Z-params, all Zij values are indeed out of range (>1e10). Somehow your data is strange, and the ADS warning is correct.

# GHZ Z MA R 1.0
2.45000000 6.365e10 0.0026 6.365e10 0.0026 6.365e10 0.0026 6.365e10 0.0026
2.45002500 6.365e10 -0.015 6.365e10 -0.015 6.365e10 -0.015 6.365e10 -0.015
2.45005500 6.365e10 0.0279 6.365e10 0.0279 6.365e10 0.0279 6.365e10 0.0279
2.45009500 6.364e10 0.0000 6.364e10 0.0000 6.364e10 0.0000 6.364e10 0.0000
2.45016200 6.364e10 0.0556 6.364e10 0.0556 6.364e10 0.0556 6.364e10 0.0556
2.45046100 6.371e11 -0.381 6.371e11 -0.381 6.371e11 -0.381 6.371e11 -0.381
2.45052700 6.365e10 -0.035 6.365e10 -0.035 6.365e10 -0.035 6.365e10 -0.035
2.45056700 6.364e10 0.0242 6.364e10 0.0242 6.364e10 0.0242 6.364e10 0.0242
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- mems @ volker_muehlhaus on Dec 11, 2017 6:36 AM
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  Thank you so much for your reply! The data is from simulation by another software.
  Set the number of points of the sweep frequency to 25/50/75/100/125/150/175 in ADS S simulation. Z abnormal, Y & S normal. No warning and error.
  
  Set other number e.g. 20 or 200. Z abnormal, Y & S normal. Got only one Warning Message:
  Warning detected by hpeesofsim during SP analysis `SP1'.
  The Z-parameter matrix does not exist because some or all of the Z-parameters are infinite. Setting all Z-parameters to zero.
  
  How to get Z-params, like "# GHZ Z MA R 1.0" you show?
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  - volker_muehlhaus @ mems on Dec 11, 2017 7:40 AM
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    As said, your S2P data looks strange, because it doesn't convert properly to Z-parameters. This is not an ADS problem - I used the Sonnet viewer to do the conversion shown, and that also results in these near-infinite numbers. The Sonnet viewer converts using the S->Z param equations you described, and it comes to the same result as ADS: near infinite Z values.
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    - mems @ volker_muehlhaus on Dec 11, 2017 5:16 PM
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      Thank you so much for your reply! Why s2p to Z strange while s2p to Y normal?
      I choose s11, s12, s21 & s22 data separately from s2p to make 4 new s1p files. S, Y & Z of 4 s1p files are all normal in ADS.
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      - volker_muehlhaus @ mems on Dec 12, 2017 10:44 AM
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        You will get infinite Z values if your 2-port circuit has only series elements (no shunt).
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s2p -> ADS, calculate Z abnormal

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