drkirkby
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There are a couple of common ways of calibrating a VNA with waveguide.
Method 1)
The 1/8 and 3/8 offset shorts have a quarter wave difference between them, which is electrically the same as the quarter wave spacer achieves.
I'm trying to find a paper which shows any actual benefit of the 1/8 ad 3/8 wavelength offset short. The theoretical advantage is the join between the waveguide and calibration standard occurs at a low current point if using 1/8 and 3/8 offset shorts, but at a high current point if using the flush short or short + 1/4 wave shim.
I believe the work on this was done at an Australian standards laboratory, although I am not sure which one. Most likely it would have been the National Measurement Institute (NMI) in Australia.
Can anyone provide a reference?
Dave
Method 1)
- Flush short
- Quarter wave spacer plus the short, to create a 1/4 wavelength offset short
- load
- 1/8 wavelength offset short
- 3/8 wavelength offset short
- load
The 1/8 and 3/8 offset shorts have a quarter wave difference between them, which is electrically the same as the quarter wave spacer achieves.
I'm trying to find a paper which shows any actual benefit of the 1/8 ad 3/8 wavelength offset short. The theoretical advantage is the join between the waveguide and calibration standard occurs at a low current point if using 1/8 and 3/8 offset shorts, but at a high current point if using the flush short or short + 1/4 wave shim.
I believe the work on this was done at an Australian standards laboratory, although I am not sure which one. Most likely it would have been the National Measurement Institute (NMI) in Australia.
Can anyone provide a reference?
Dave