Vector Network Analyzer Check Standards Measurements and Database Software

Vector network analyzers provide a convenient way to measure scattering parameters of a variety of microwave devices. However, these instruments, unlike oscilloscopes for example, require a relatively high degree of user knowledge and expertise. Prior to use, the network analyzer must undergo measurement calibration or error correction. Due to the complexity of the instrument and of the calibration process, there are many ways in which a poor measurement calibration or measurement may be produced. Check standards have been used to verify that the network analyzer is operating properly. In the past, the measurements were recorded manually and, sometimes, interpretation of the results was problematic. To aid our measurement assurance, a software program was developed to automatically measure a check standard and compare the new measurements with an historical database of measurements of the check standard device. The program can acquire new measurement data from selected check standards, plot the new data against the mean and standard deviation of prior data for the check standard, and update the database files for the check standard. This paper describes the function of the software including a discussion of its capabilities. The way in which the software is used in our lab is also described. Finally, some examples are given showing how the software can detect potential measurement problems.