FAQs from Rohde & Schwarz

FPC1500 - Calibration of S11 and S21


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