Precision Calibration Coefficients for the Reciprocal Procedure

The reciprocal procedure is a modern calibration and calibration standard characterization technique which uses the theoretical reciprocity of the S-parameter matrix (Sxy=S_yx) of a verification standard. The thru calibration standard is the only true precision standard in the reciprocal procedure. In addition to the thru coefficients, the dc load impedance must be precisely measured. The 1-port standards (short, open, and load) are generally not precision standards, but they can be accurately characterized during the reciprocal procedure and later used as precision standards in a traditional calibration. We discuss measurements of the precision calibration coefficients and their importance for the accuracy of the reciprocal procedure solution