A calibration technique of 4-port vector network analyzers with a general 12-term error model

A general 2-port block diagram with 12-term error matrixes is presented for the calibration of a 4-port vector network analyzer(VNA). Extending the classical 12-term error model to describe the 4-port network analyzer, all the coefficients in signal paths are replaced by the complex square matrixes and the nodes correspondingly become complex vectors. The scattering matrix can be solved from the forward and reverse general 12-term error model. This is a unified method for the 2-port VNA and 4-port VNA with the same flow graph. Experiment results of a 4-port device attest the good performance of the general 12-term error model.