Electronics > RF, Microwave, Ham Radio

VNA One Port Fixture De-Embedding Experiment

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--- Quote from: Nitrousoxide on May 17, 2021, 10:22:34 am ---Yep. It completely zeros out the fixture, almost like I'm taking a "delta" measurement. That's basically what I figured I'd do in my original post. Also, what do you mean by "up to an overall phase"?

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If I'm not mistaken, when you do trace normalization with a short i.e., do the \$S_{11}^{\text{meas}}/S_{11}^{\text{ref}}\$, you get an extra phase factor of \$\exp(\mathord{\rm i}\pi)=-1\$. When you do the same with an open, your extra phase factor is just \$\exp(\mathord{-\rm i}0)=+1\$. The "Direct Compensation" function should take care of that automatically. If you use trace math instead, you'll have to compensate for the \$-1\$ manually.

Edit: Corrected the math. The statement should be ok now.


--- Quote from: Nitrousoxide on May 17, 2021, 10:22:34 am ---R&S ZNL has auto port extension (estimate the phase delay and loss) built-in.

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Yeah, they added it after we did.  I like my implementation better, fitting is better I think.

--- Quote from: Nitrousoxide on May 17, 2021, 10:22:34 am --- It also has the provisions of defining a custom cal kit at no added cost required, something I know that you have to pay for with Keysight VNA's (I know because the mmWave guys next door keep complaining about it).

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  As far as I know, you can create whatever cal kits you want just by creating a new one. There is a paid-for version of a wizard in the PLTS that does quite complicated things, but for normal cal kits I think the free version is available. I just downloaded on my home PC and it seems to not require any license.  I got it here: http://na.support.keysight.com/pna/apps/#calkiteditor
Of course this makes calkits that are compatible with Keysight VNAs, maybe you have to change the units to Euros or something to run on other products.
the same page has a bunch of little helper code.


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