Good shielding performance has two meanings, one is that the system does not release electromagnetic waves that affect other systems, and the other is that the system itself is not affected by external electromagnetic fields. The occurrence of shielding failure has three elements, namely, interference source, coupling path and sensitive equipment. The interference source on the vehicle mainly includes the ignition system, inverter, relay and other equipment that can send out electromagnetic signals to the outside. The coupling path is composed of air and the vehicle circuit, and electromagnetic waves are transmitted in the coupling path. Sensitive devices are easy targets for interference. The wire harness system is quite special. The wire harness can be the carrier of conductive coupling and the equipment that is easily disturbed. Therefore, the research on the electromagnetic shielding of the wire harness is of great significance.
The wire harness is an important propagation path for conduction coupling interference. The electromagnetic interference signals generated by various electronic devices during the working process directly enter the sensitive equipment through the wire harness conduction, or enter the control loop and signal loop in the wire harness through capacitive coupling or inductive coupling.