A Reformulation of LNN Calibration

In this paper, the line-network-network (LNN) calibration is reformulated based on the T-matrix representation. Firstly, the T-matrices of error boxes are constructed by measuring the line standard, and only three wave ratios need to be solved. On this basis, an unknown obstacle is placed and measured at three positions of the transmission line to solve three wave ratios. Once three wave ratios are obtained, the T-matrices of error boxes are determined. Finally, the validity of the proposed method is proved by the experiment.