Vector Network Analyzer Calibration Using a Line and Two Offset Reflecting Loads

In this paper, the line-offset offset-open offset-short (LZZ) calibration technique for vector network analyzers (VNA) is introduced. The LZZ uses as calibration standards a fully known transmission line and two offset reflecting loads. The mathematical formulation of the LZZ is based on the use of ABCD-parameters for modeling the imperfect VNA as well as calibration standards. As a result, it is shown that the error coefficients characterizing the imperfect VNA can be calculated by comparing the estimated impedance of the two loads with the characteristic impedance of the transmission line. In order to validate the proposed method, the line-reflect-line (LRL) and the line-reflect-reflect-match (LRRM) calibration techniques are used. A high correlation between the S-parameters of a heterostructure field-effect transistor corrected with the LRL, LRRM, and LZZ techniques up to 45 GHz is achieved.