Characterization of Coaxial Adapters for S-parameter Measurements

The accuracy of S-parameter measurements can be improved by replacing calibration kits for industry grade connectors by a combination of one calibration kit for metrology grade connectors and well characterized adapters. This paper compares two methods to characterize such adapters which join metrology grade coaxial connectors with industry grade connectors. A first method employs a thru connection as well as opens and shorts with industry grade interfaces to obtain the full S-parameters of an adapter. The second method uses beadless adapters rather than opens and shorts. It is shown that the second method is superior in particular for frequencies above 30 GHz.