Analysis of radiated emissions from flexray automotive bus systems

Due to the high data rates of FlexRay communication systems, EMC can be a big challenge. It is crucial to develop new and fast methodologies to evaluate electromagnetic disturbances. This paper focuses on the radiated emissions from FlexRay communication systems, which is mainly induced by common mode current on the twisted-pair cable. VHDL-AMS modeling language is employed to investigate common mode currents in FlexRay bus networks. An equivalent common mode radiation model of a twisted-pair cable above a reference ground plane is established by simplifying it into a single transmission line parallel to ground. Through combing common mode currents as radiation source by VHDL-AMS analysis with a simplified radiation model, efficient analysis of radiated emissions from bus networks is possible. The proposed fast approaches are an analytic method and a multiple-dipole method based on Green function and mirror theory. The radiated emissions from different topologies of automotive networks are analyzed and verified by full wave methods.