Hi,
We built a custom calibration kit to calibrate out our RF switch and cable. Below is a picture of it and the VNA response to "open" post calibration.
My problem is that there seems to be a large error in my measurements. For example I am measuring the impedance of a dev-kit which is supposed to be 50ohms, but my VNA shows 20 + 10j; really far off.
I think the issue is my "calkit" settings, for this custom calibration board I must define the calkit. I don't need this to be extremely accurate, in fact all I want is for the VNA to NOT correct for any calkit parasitics. I'm sure the calkit parasitics are way less than the parasitics I'm trying to match out - my matching network will be an order of magnitude larger than any calkit parasitics.
I'm struggling to get my "open" impedance to have no imaginary component when connected to the VNA, can you offer any advice?
Looking at my calibration board, can you offer rough offset delay,loss and impedance values?
Thanks a lot, Will
I found this blog which explains how to use custom cal kits, filling in a lot of blanks left in the user manual
Setup an HP or Agilent 8753 VNA to use a calibration kit
But my post-calibration inspection of a 50ohm impedance is still shifted to the top left of the smith chart. Which calibration coefficients are incorrect to result in a shift like this?