An Error Correction Procedure for Multi-Port Measurements at High Frequencies

摘要

The multi-port method for the measurement of the scatteringparameters of multi-ports with the help of a vector networkanalyzer (VNA) with only two measurement ports is presented. Forthe measurements only two ports of the N-port device can beconnected to the two ports of the VNA at a time. The remainingN-2 ports of the device under test (DUT) are connected toexternal terminations. As these external terminations might bemismatched, the measured scattering parameters depend on thereflective characteristics of the terminations. An errorcorrection becomes necessary in order to calculatethe effective scattering parameters of the DUT (Tippet and Speciale, 1982; Lu and Chu, 2003).In contrast to the correction method of Tippet and Speciale (1982), themulti-port method has the advantage, that the externalterminations can be chosen arbitrarily. Thus, a realization as anopen or short circuit is possible as well. Furthermore, theterminations can be unknown except for one, similar toself-calibration procedures of VNAs. This helps to improve theaccuracy of the measurements, because the inconsistency problemdue to a slightly erroneous knowledge of the frequencycharacteristics of the terminations can be eliminated.