De-embedding setup-related effects to characterize an EM clamp for conducted immunity testing

This paper describes an experimental procedure for the identification of a frequency-domain behavioral model of the electromagnetic (EM) clamp used for conducted-immunity (CI) testing according to Standard IEC 61000-4-6. The model does not require knowledge about the internal characteristics of the EM clamp since it is extracted from scattering parameters measured at the external ports of a calibration setup designed ad hoc. In particular, a post-processing method is used to de-embed the additional contribution of such a calibration structure from measurements. It is shown that the identified model can be used to predict voltages/currents injected by the EM clamp in a CI test setup, for different operating conditions such as different impedance of the auxiliary equipment, and different positions of the EM clamp on the wiring harness.