VNA View (Cal Kit Parm Setting) Question

[Mechatrommer]

i have a brainfart moment trying to get this right... simple question at first is...

1) what is this for? (1st attached file 1v.jpg... i have s1p files for my cal kit all right, but...)
2) when should i leave it as in 2v.jpg? (parms = ideal)
3) when should i leave it as in 3v.jpg? (parms = set to corresponding s1p files)

to get the idea what was wrong...
- i made calibration with parm set as ideal ie 2v.jpg and got saved into a cal file (lets call it calibration 1 or C1)
- i made another calibration with parm set as in 3v.jpg using s1p files set and got it saved (lets call it calibration 2 or C2)

and then when i do real measurement i will get wrong answer (graph plot) if i leave the setting as in 3v.jpg and load either C1 or C2. i can only get correct plot if i leave the parm as ideal (2v.jpg) regardless if i load C1 or C2. i thought we should always set it to the cal kits's s1p files and then load the calibration file (regardless C1 or C2) to get correct plot.. or to be more logical... if we set to ideal cal kit parm, only loading the C2 can we get correct answer... correspondingly, if we set the cal kit parms to cal kit's s1p files, only if we load C1 then we will get correct answer, not the other combination. but i dont get this logic on my VNA View (PC SW) screen. this is brainfart... please explain to me.. thanks.

(ps: this was not an issue with my KC901V VNA since it doesnt support loading cal kit's s1p files into calculation)

[Mechatrommer]

no one? it looks like i'm at the leading edge at this

[Mechatrommer]

Copper Mountain App Note:
INTRODUCTION TO USING DATABASED CALIBRATION KITS

Kirkby Microwave App Note:
Verifying the performance of a VNA after calibration with a Calibration Kit

Mario Hellmich's Private Homepage
https://www.mariohellmich.de/projects/sma-cal-kit/sma-cal-kit.html

[Mechatrommer]

1) what is this for? (1st attached file 1v.jpg... i have s1p files for my cal kit all right, but...)
2) when should i leave it as in 2v.jpg? (parms = ideal)
3) when should i leave it as in 3v.jpg? (parms = set to corresponding s1p files)

1) to load S11 characteristic of your CAL kit
2) when you have super perfect with zero offsets and zero fringings CAL kit, or if you want to do fancy "out of the plane" or "relative" measurement
3) when you want to do (or close to) correct S11 characterization of DUT at VNA's measurement/reference plane. you should load your CAL kit's s1p profiles (if available) as in 3v.jpg, load the saved calibration files, and then you can start to do measurement.

to get the idea what was wrong...
- i made calibration with parm set as ideal ie 2v.jpg and got saved into a cal file (lets call it calibration 1 or C1)
- i made another calibration with parm set as in 3v.jpg using s1p files set and got it saved (lets call it calibration 2 or C2)

and then when i do real measurement i will get wrong answer (graph plot) if i leave the setting as in 3v.jpg and load either C1 or C2

thats because by loading CAL kit's s1p (S11) profile, you are moving the measurement plane back to the VNA/SMA connector's reference plane, and possibly to correct the fringings effect of your CAL kit. hence what you are seeing when connecting your CAL kit into VNA's connector is the offsets and fringings effect of your CAL kit as characterized from factory. when you insert a DUT into the VNA connector, VNA will measure the DUT's S11 at the connector's reference plane.

dont quote me on this though, i've only done limited test and study about this matter, so there maybe mistakes. different VNA may also gives different result based on their quality and price. cheers.

[Mechatrommer]

great! thanks for clarifying at last i have the answer. <split personality mode off> so i've answered/solved my own questions, thanks to xaVNA Qt and NanoVNA FW source code and manual and Mr Kirkby's website and Microsoft for providing me VB6 to do the simulation (S11 parameter analysis) and most importantly to my and your Creator the most wise and knowledgable the source of Evvvvverythings for granting me a small chunk of understanding. ymmv.

[virtualparticles]

There is a pretty good webinar on this at the Copper Mountain Technologies site.

https://coppermountaintech.com/webinar-series/

Best,

Brian