A Generalization of the TSD Network-Analyzer Calibration Procedure, Covering n-Port Scattering-Parameter Measurements, Affected by Leakage Errors

The basic philosophy of the through-short-delay (TSD) calibration procedure for two-port automated network analyzers has been extended to n-port scattering-parameter measurements, while also accounting for the errors due to possible signal leakage between all port pairs. The system errors are represented by the scattering response of a 2n-port virtual error network, having n ports connected to the device under test and n ports connected to an ideal error-free multiport network analyzer. The (2n)² T-parameters of the error network are explicitly expressed in blocks of n² at a time, as matricial functions of the 3n² S-parameters of three n-port standards, sequentially replacing the device under test during system calibration. The possibility has also been investigated of correcting the errors due to repeatable measurement-port mismatch changes, typical of switching scattering-parameter test sets. This capability has been introduced and tested in the classical two-port TSD calibration algorithm, by means of a minor modification and data postprocessing, applied after the removal of conventional errors.