Network analyser calibration 1

[calConfusion]

Hi

I am attempting verification of the calibration standards that I am using on an old Rohde and Schwarz ZVRE network analyser.
The plan is to measure my standards on a new system calibrated with new standards and an accurate Cal Kit that I will have access to for a day. Then using these measurements I want to adjust my Cal Kit so that calibration with my standards are more accurate.

How do I relate the measured S-parameters to the values that I need to adjust in my Cal Kit saved on the VNA like Open parasitic capacitance and Short parasitic inductance and Load impedance?

Any help appreciated.

 

[Higgler]

I've borrowed the same cal kit from a neighboring company, calibrated with theirs, then checked mine against theirs for comparison. You could do the same.

Cal kit data is a simple approximation with a few simple number using offset length and a capacitance. Agilent stores this simple info in firmware and when you specify which cal kit, it looks up these values for the short and open.

Measured Data points on loads, shorts and opens aren't usually stored in an analyzer to be used later. Hence the use of a "Verification Kit" to just make sure the shorts and opens look ok. Proving enhanced accuracy by measuring your cal kit needs the other machine to be proven super accurate. What if it just passes with the verification kit?

Suggest you consult with Rhode on your gameplan too.
Good luck.

 

[biff44]

That would work only if you have access to the actual data on the borrowed cal kit. When you pick a "short circuit" out of a cal kit, it does not necessarily have p=1 with angle -180.0000 degrees! It will have some loss, and more importantly have an phase angle that is off a little.

http://www.MaguffinMicrowave.com

Maguffin Microwave wireless design consulting

 

[calConfusion]

How could I determine the loss and phase angle with reasonable accuracy? If I could measure these losses and offsets then setting up the characteristics of my standards should be easy and lead to improved calibration right?
I'm new to VNA calibration and measurements

 

[biff44]

Those are parameters that are stored in the network analyzer they are married to, albeit in weird form sometimes (like capacitance and delay). On my analyzer I can go into the cal settings and read them off.

You could calibrate you friend's an analyzer, measure the unknown cal set for magnitude and angle, and then you would know what they should look like on your analyzer.

http://www.MaguffinMicrowave.com

Maguffin Microwave wireless design consulting