The self-calibration of six-port in the presence of noise

The concept of middle constants, which are all functions of system constants only, is introduced. A self-calibration method in which system constants are calculated from middle constants is proposed. A linear least-square recursive-identification formula is derived to self-calibrate middle constants in the presence of noise. This formula convergers if the noise follows a normal probability distribution. A method to realize the large-sample condition is also suggested. This method might be able to trace the slow shift of system constants