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Difficultly using Adaptor Characterization at high frequency?

Question asked by BrianAllred on Mar 18, 2014
Latest reply on Mar 20, 2014 by daras
Instrument: N5242A
Firmware 9.33
Adapter Characterization Macro: A.02.10

Problem Description:
We're having difficulty trying to get a cal with a low amount of variance on a thru (after ~10GHz)
We can get a clean cal after performing the cal manually.
(I don't have images, this is in a secure area.)

The (broad) steps we're performing in the automated version of the calibration are:
1. Preset
2. Perform a full 2-port cal, as the reference path
3. Perform 1 port cals for all inputs and outputs (approx 30 each)
4. Run Adapter Characterization macro for each 1-port and reference
5. Add results of Adapter characterization as fixture for each combination of ports
6. Flatten fixture into calibrations
7. Test

(My apologies for not having the code with me, this is all from memory.)

If we perform these steps, for the most part, we get a good calibration.  Occasionally, a path might have that high variance (> approx 0.1 dB around 20GHz), which is not present on a direct manual calibration of the same path.
  (We're not expecting the two cal types to line up exactly, just to be in the same ballpark.)

Is there anything we're missing, or that we could do better?
Let me know if there is any more information that I could provide.

Thank you