EMC test method for coupling into and decoupling from the wiring harness of automotive components in the VHF band

For EMC component tests on automotive equipment a high electrical field strength (up to 200 V/m) is needed. The generation of this field strength with antennas in the frequency range from 100 MHz to 3 GHz requires an amplifier power up to 100 W and a measurement distance partly shorter than 1 m. The short measurement distance may lead to different test results when using a test set-up according to ISO 11452 part two. The wave coupler is a proposal for a new alternative test method to measure the susceptibility and radiation of small and shielded electronic components with connecting cables (wiring harness). It is based on a coupling and/or decoupling of disturbances into the connecting cables with low insertion loss (7 to 11 dB) and a broadband coupling function (200 MHz to 3 GHz). This procedure leads to two disturbing components for the equipment under test (EUT): a conductive component and a radiated component, caused by the scattering field from the disturbing current in the connecting cable between the coupler and the EUT. Measurements of the susceptibility of EUT show a very good reproducibility and a comparability of the test results to antenna test method.