Characterization of Multi-Gigabit Automotive Ethernet Channel Radiated Emissions in Relation to ECU PCB Shield-Ground Implementations

One of the main objectives of deploying Shielded Twisted Pair (STP) cables for Automotive Ethernet communication channels is to prevent ElectroMagnetic Interferences (EMI) from coupling onto sensitive in-vehicle sub-systems. Aside from the fact that currently various in-vehicle Electronic Control Unit (ECU) Printed Circuit Board (PCB) shield-ground implementation concepts are being deployed, there are several uncertainties regarding the correlation between these implementation concepts and their impact on radiated emissions of a multi-Gigabit Ethernet communication channel. Based on a defined Point-to-Point (P2P) emulated multi-Gigabit Ethernet communication channel topology, this study first commences by characterizing the channel ElectroMagnetic radiated Emissions (EME). To rule out potential impact of varying STP cable types in terms of their specified frequency coverage and vendor, this study further investigates, compares, and characterizes radiated emissions based on two commonly used STP cable types. The Automotive Ethernet multi-Gigabit speed grades in question include the recently standardized IEEE 802.3ch 2.5Gbps (2.5GBASE-T1), 5Gbps (5GBASE-T1), and 10Gbps (10GBASE-T1). Subsequent sections of this study investigate and characterize sources of the measured radiated emissions in relation to ECU PCB shield-ground implementation. Through this study, the correlation between Radio Frequency (RF) characteristics of an ECU PCB shield-ground implementation and radiated emissions of an Automotive multi-Gigabit Ethernet channel is shown. Additionally, analysis and simulation approaches are defined on how the sources of multi-Gigabit channel EME can be investigated and traced within the ECU PCB shield-ground implementation.