I use the FPC1500 in Network Analyzer Mode for S11 Reflection as well as S21 Transmission measurement and always perform calibration / normalization for each mode before I begin with the real measurement job.
When I then change from reflection to transmission, I can see, that my normalization got lost. This also seems to happen with the S11 calibration.
What can I do to avoid that?
When performing measurement with the FPC1500 (Ref. FW 1.50) while being in Vector Network Analyzer Mode, the following main scenarios are available:
- Reflection S11
- Transmission S21
- 1-Port Cable Loss (works in S11 mode)
- Distance To Fault (also works in S11 mode)
- Reflection / Transmission S11/S21
The FPC1500 only stores one calibration at the same time, meaning that "Full 1-Port" will overwrite "Normalize S21". So it's important to choose the right calibration before starting the main measuring task.
When comparing the sub menus of the different main scenarios, "2-Port Selective Span" is the only way offering both - transmission and reflection mode calibration. So we recommend the following strategy to execute a measurement including calibration:
- Use the [Preset] key on the analyzer for being sure, to start with a well defined setup
- Connect your DUT, preanalyze it and do all the settings to be done for the final measurement
- Only now it's the right time to perform the calibration
- [MEAS]
- (Calibrate)
- (Calibration Kit)
- Check for the right calibration kit
- (Back)
- (2-Port Selective Span)
- Perform the calibration
- Now you are ready to do the final measurements
--> Extra hint for elder firmware versions:
In former firmware versions the "2-Port Selective Span" is not available, thus it makes it necessary to find a workaround.
When using the defaut calibration, the result will be the same:
- [Setup]
- Scroll down to "Calibration Kit"
- Choose the right kit
- Scroll to "Calibrate" and press (YES)
- Perform the calibration
