S-Parameter Measurement Comparison
Have you ever calibrated your vector network analyzer (VNA) and wondered if your measurements were right? Has your boss walked in and asked you how you know that your results are correct? Wouldn’t it be nice if there were an easy way to have confidence in your measurements? Standard round-robin experiments and interlaboratory comparisons are good approaches to knowing about your measurement process; however, they have definite limitations such as difficulty in dealing with large amounts of data and long turn-around times. A program set up particularly for VNA measurements, such as the ARFTG Measurement Comparison Program (MCP), may be a better way to answer questions such as those above.
The ARFTG MCP is a process that allows a participant to compare the results of a measurement to the statistical “average” of the results of all the other participants. Included in the data are results from national metrology institutes, instrument manufacturers, calibration labs, and general users. The kits used for the tests are designed to cover as much of the VNA’s range as is practical. At present, the ARFTG MCP is established only for scattering parameter measurements based on coaxial connectors.
The process for using the MCP is fairly simple. Three different sets of data are taken for each device in the kit. The instructions for the kits give you the information on how the data for the measurement passes must be stored. Once the data have been obtained for all the devices, the results are sent to the ARFTG MCP data coordinator, who will analyze the results and send you a report of the analysis results.
- Adapted from "Confidence in VNA Measurements" by Ronald A. Ginley, IEEE Microwave Magazine vol. 8 issue 4, pp54-58, August, 2007
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