Prediction of Radiated Emissions of Automotive Electronics Early in the Design Phase based on Automotive Component Level Testing

Gregor Ergaver, Janez Trontelj


A method of predicting radiated emissions levels of automotive component level testing in the early design phase of an automotive electronics from a cable harness is presented. Instead of the time consuming and inaccurate common-mode current measurements on a cable harness with a RF current probe, this paper proposes a novel common-mode current distribution prediction on a cable harness with the multi conductor transmission line model from imported boundary line currents or voltages from an EM simulator taking into the consideration a PCB layout and components, connectors, 2 D model of cable harness, cable harness loads etc. Radiated emissions levels are calculated from predicted common-mode current distribution on cable harness. This paper uses a component level CISPR25 cable harness layout for radiated emissions levels prediction. A radiated emissions prediction model enables an engineer to evaluate radiated emissions levels in the early design phase, when the product is still virtual and a prototype has not yet been fabricated. As a result, radiated emissions levels can be optimised and the lowest cost solution can be obtained. This approach lowers the overall cost and time needed for automotive component design. The model substitutes a 3D model of cable harness above the ground plane in EM simulator and is thus much faster and uses less resources with same or even better prediction accuracy.  The proposed method is validated in two absorber lined shielded enclosures (ALSE) both with an accreditation according to ISO/IEC 17025. The deviations between prediction and measurements in both ALSE are explained.


cable harness; CISPR25; common-mode current; EMC; radiated emissions

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