A new assessment method for the residual errors in SOLT and SOLR calibrated VNAs

The traditional residual error assessment methods for the vector network analyzer (VNA) are improved by using measurements from both SOLT and SOLR calibrations. The difference in sensitivity to residual errors for the SOLT and SOLR algorithms is utilized to assess the residual directivity, match, and tracking of both VNA ports. A two-port measurement on an airline is used in the assessment. Even though two-port measurements are used the resulting residual errors are applicable to one-port SOL measurements as well. Compared to earlier methods, which use oneport airline measurements, the number of airline connections is reduced to one fourth. Yet the quality of the assessment is improved. The residual match is now assessed independent of the residual directivity giving a better accuracy. The residual transmission tracking, which was earlier unavailable, is also obtained. For hermaphroditic connectors such as APC-7, waveguides or probed MMIC measurements, the method will also provide the residual reflection tracking, which the traditional ripple methods fails to provide at all. The method is compared to earlier assessment methods with measurements on a calibration in type-N connectors.