EMC of Cables, Connectors and Components with Triaxial Test set-up: New and revised IEC 62153-4 standards to measure Transfer Impedance and screening or Coupling Attenuation

摘要

New designed cable constructions, e.g. for electro vehicles with characteristic wave impedances in the range of 10 Ω required the revision of different standards of the IEC 62153-4-x series which described different test procedures to measure Transfer Impedance and Screening- or Coupling Attenuation on cables, connectors and passive components with the Triaxial Test set-up. The revised standards IEC 62153-4-3, -4-4 and -4-7 now allow the measurement of screening characteristics of cables, connectors and components under mismatched conditions; impedance matching devices are no longer needed. The changes of the revised standards are also included in the revised "Tube in Tube" test procedure as well as in the draft standard for the newly designed "Triaxial Cell". In order to measure the Coupling Attenuation of balanced cables, a differential signal is required. This can be generated using a balun which converts the unbalanced signal of a 50 Ω network analyzer into a balanced signal. Commercial baluns, however, are only available up to 1.2 GHz. Alternatively a balanced signal may be obtained with a network analyzer having two generators with a phase shift of 180 °. Another alternative is to measure with a multi-port VNA. Both options allow "balunless" measurements of Coupling Attenuation up to and above 3 GHz. Comparative measurements with balun and with multi-port VNA show good correlation.