ISO 11451-4:2022

This document specifies harness excitation methods for testing the electromagnetic immunity of electronic components for passenger cars and commercial vehicles regardless of the propulsion system (e.g. spark-ignition engine, diesel engine, electric motor).
The bulk current injection (BCI) test method is based on current injection into the wiring harness using a current probe as a transformer where the harness forms the secondary winding. The tubular wave coupler (TWC) test method is based on a wave coupling into the wiring harness using the directional coupler principle.
The TWC test method was developed for immunity testing of automotive components with respect to radiated disturbances in the GHz ranges (GSM bands, UMTS, ISM 2,4 GHz). It is best suited to small (with respect to wavelength) and shielded device under test (DUT), since in these cases the dominating coupling mechanism is via the harness.
The electromagnetic disturbance considered in this document is limited to continuous narrowband electromagnetic fields.
ISO 11451-1 gives definitions, practical use and basic principles of the test methods.