Precise Calibration of Common Mode Impedance Modulus of Coupling/Decoupling Network

The calibration method of the common mode impedance modulus of Coupling/Decoupling Networks used in the immunity of conducted disturbances induced by radio-frequency fields in EMC test and measurement technique is introduced in this paper, with the main focus toward the compensation method for the influence of the cable length on the common mode impedance modulus. In the beginning of this paper, the specification of the common mode impedance modulus of Coupling/Decoupling Networks is presented, followed by the introduction of the calibration standards and corresponding specifications used in calibration, with elaboration on the calibration method of the common mode impedance modulus by using network analyzers with or without the cable length compensation function. Finally, the calculation formula of compensation is presented as well.