The Consequences of Missing Specification for Coupling-Decoupling Networks

Coupling-decoupling networks (CDN) are used in electromagnetic compatibility (EMC) conducted immunity testing according to IEC 61000-4-6. This standard defines the requirements for CDNs to achieve a good reproducibility [1]. However, during the analysis of a recent international interlaboratory comparison (proficiency testing) on conducted immunity testing [2], we observed some deviations in the participant results that could not be explained by evident reasons such as bad earth connection, broken cable or faulty setup. A careful analysis has demonstrated that CDNs from different manufacturers might behave significantly differently with given equipment under test (EUT), despite the fact that they are all compliant with the standard IEC 61000-4-6.