MultiPath Full 2-Ports Calibration

Application

Used to calibrate Multiple 2-ports systems when small signal measurements in Forward and Reverse modes are required:
Calibration steps:
  • For each path :
    • Full 2-ports calibration

Setup Editor Requirement

In IQSTAR, the calibration wizard is linked to the Setup Editor configuration. In order to get access to a full 2-Ports calibration wizard, the following conditions have to be respected:

Calibration Wizard

To start a new calibration, select Calibrations tab and click on New Calibration . The software will verify communication with each instrument needed and will configure it using the settings previously defined.



Once all required hardware are listed, click ‘Next’.

Select the RF path to calibrate.
Note: Unselected paths won't be calibrated and so not available during measurement.


Define the frequency list and the input and output power levels of the VNA. These power levels should not exceed the maximum power supported by the calibration kit, yet the level should be sufficient to provide noiseless and detectable signals at the VNA receivers even when adding attenuators to keep the receivers safe during the DUT characterization.
Note: It is possible to set different power levels for the input and the output port. this setting is useful when the DUT has a high gain, leading to unbalanced attenuation settings between the input and output receivers.


In the example above, the sweep type is frequency sweep starting from 1GHz to 10GHz with 50MHz step. To define appropriate attenuator values on each receiver, see 2) Power Budget.

Once the frequencies and the VNA power level have been set, click ‘Next’.
Note: All the parameters (IFBW, Power level, Frequency sweep, Pulse Timings) will be automatically set in the VNA, according to the Setup Editor configuration. Depending on the VNA model, a 'Single' Trigger is needed to update the settings.


At this step, a classic Full-2 ports calibration using the VNA interface has to be performed on each path.



When the calibration is finished on the VNA, go back to IQSTAR and press ‘Retrieve error terms from VNA’ to fetch back error terms corresponding to the selected path in the drop-down list. Once error terms are fetched the slected path becomes green.



Once first path has been calibrated, use drop-down list to select second path and force swith matrix to swicth on second path.

Then re-perform a new classic Full-2 ports calibration on second path using the VNA interface, as described previously.

This Full-2 ports calibration step will be done iteratively for each RF path until all RF path are done and become "green".



Note: When RF paths are similar, error terms retrieved for a specific path can be used for other paths using "Copy" button. In this case, the path using error terms form another path becomes "black".

In addition, pressing ‘S-Parameters calibration Check’ can be use to validate each vectorial calibration on each path and/or save a 'Thru.s2p' file. Learn more see Validate Calibration.



Note: If the frequency list contains too many points, the VNA sweep may take a long time and may cause a timeout error. To avoid this issue, one need to increase the VNA timeout in the instrument settings Vector Network Analyzer

Once the calibration has been completed, the error terms are downloaded and recorded in Calibrations tab. A default comment is automatically added but it could be modified. This calibration will be used by default for the measurement unless the box Use this calibration is unchecked.

Quick checks can be performed to verify the accuracy of this calibration using Validate calibration button. To learn more see Validate a MultiPath Calibration.