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VNA Measurement Issue on VSS

KK202507285148

Hello, I was trying to get some measurements like OIP3, OP1dB and such as on VSS. I was using a ADL8142 and connected a VNA to it. I also specified the FSTART and FSTOP as 23/31 GHz and I have added the netlist to my AMP_F. But there is a problem.

1- When all the columns and values from the netlist are available (Freq(,MHz) Gain(,dB) NF(,dB) OP1dB(,dBm) OPSAT(,dBm) RISO(,dB) OIP3(,dBm) S11(mag,dB) S11(phs,deg) S22(mag,dB) S22(phs,deg) OIP2(,dBm)), the measurements for Gain, NF and etc. are wrong compared to the datasheet. Also, the netlist data are directly from their website so it shouldn't be a problem.

2- When I delete all the columns except Gain and NF (Freq(,MHz) Gain(,dB) NF(,dB)) and measure again, they become right.

3- When I add a single column of OP1dB (Freq(,MHz) Gain(,dB) NF(,dB) OP1dB(,dBm)), they become wrong again.


Is there an explanation for this which I am missing? I am new to AWR and especially VSS and it is important for my project. Thanks!

  • CurtisAWR

    Is it possible for you to go to support.cadence.com and open a support ticket?

    This may be the best way for us to proceed, as the troubleshooting we are likely to do may require a more in-depth interchange, and possible exchange of project files or screenshots.

    I did go to Analog's site to try to download the data sheet you are working with, but I am already concerned that we may be looking at different documents and/or using the data sheet in a different way in the project.

  • KK202507285148
    in reply to CurtisAWR

    Hello, 

    Thanks for the reply. I assume support ticket is "create case" in the support page but it wants a premium so I was'nt be able to open a support ticket.

    I can further share the datasheet link as below,
    https://www.analog.com/en/products/adl8142-2.html

    I downloaded the s-parameters file here, there were 3 s2p files and a rfamp file in the excel format where it contains other attributes like OIP3, OP1dB and such as. I corrected their format and I assume my format is right because as I said it works when I delete the columns until NF and they are matched with the datasheet.

    I also want to further add some screenshots to provide better information but system gives an error so I can not upload. Maybe I can mail it to you or any other if you can inform me, I can do it.

    Best regards and thanks for your time.

  • KK202507285148
    in reply to CurtisAWR

    Hello again,

    Thanks for the reply, I assume support ticket is "create case" in the support page but since it wants a premium I can not be able to create it.

    I can also share the full name of the component I used as below,

    ADL8142-2 (ADL8142-2CHIP in the datasheet)

    There were 3 s2p files and one rfamp file in excel format where it contains the attributes like OIP3, OP1dB and such as. I also corrected the formatting in the excel file because when you directly copy paste it, it does not work. Also as I said, it works parallel and correct compared to the datasheet if we delete other columns until NF. So I am confident that there might be an another problem.

    I also further wanted to add some screenshots but when I upload them, site gives an error and do not show here. I there is any way other than that, like mailing it to you, I can do it if you guide me.

    I just connected a VNA to it and wanted to verify the values given in the rfamp file are similar to the datasheet like Gain, NF, OIP3, OP1dB and such as, there were no additional components or connections.

    Best regards and thank you for your time.

  • CurtisAWR
    in reply to KK202507285148

    Can you check the power level on your VNA vis-a-vis the expected saturation on that device?

    I saw something similar to what you describe as the device started to really saturate (started accelerating when the power level of that VNA went more than about -17 dBm or so).  But below that, the data agreed pretty well.

    See screenshot below:

  • KK202507285148
    in reply to CurtisAWR

    Hello again,

    I tried with the -30 dBm you mentioned in the screenshot and as you said, data agreed well compared todatasheet. In the datasheet around pages 10, we can see P_sat in dBm and most of them start from 8 dBm and go until 15-16 dBm. I think they are consistent and the reason behind my wrong results. I normally used a 0 dBm output power for the VNA. I think that was the answer for my question why it was acting off the datasheet.

    Thanks for all your help!

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