Calibration And Correction Of 4-port Vector Network Analyzer

On the basis of calibration and correction theory of 2-port vector network analyzer (VNA), this paper focuses on calibration and correction of 4-port VNA. In addition, measurement method of mix-mode S-parameters of balanced components using single ended 4-port VNA is studied.First of all, the 48-term error model of 4-port VNA is established. By understanding the work procedure of VNA and comparing the 12-term error model of 2-port VNA, a simplified 4-port model is obtained. The idiographic method is that error model of 4-port VNA is taken as generalized 2-port VNA model. In this model, nodes and paths are treated as column vectors or matrices respectively. Then the method similarly to that used in 2-port VNA calibration is adopted to deal with 4-port VNA with matrix operation. The corrected S parameter of 4-port devices is gotten in matrix form finally.Currently, balanced devices are more and more widely used in electronic systems. So their measurement becomes an urgent issue. Mathematical balun theory is used in the measurement based on single-ended 4-port VNA of mix-mode S-parameters. The expression of mix-mode S-parameters of balanced devices is deduced.At the end of this thesis, the calibration and correction of 4-port VNA is demonstrated with a practical 4-port device. It is shown that the results are quite well. Moreover, a 4-port dual directional-coupler is used as a personator of balanced device to verify mathematical balun theory. Good agreement of results with that of Agilent equipment is observed and the mathematical balun theory is proved effective.