Analysis of the Influence of Mode Conversion Characteristics of Twisted Pair on Automotive Ethernet EMI

Automotive ethernet is a new type of local area network technology that connects electronic units in the vehicle. On a single pair of unshielded twisted-pair cables, data transmission rate of automotive ethernet can reach 100 Mbit/s or even 1 Gbit/s, meeting the requirements of high reliability, low EMI, low power consumption, bandwidth allocation, low latency, and real-time in the automotive industry. At the same time, automotive ethernet also puts forward higher requirements on its physical layer. Based on the EMI test of the automotive ethernet link, the influence of the differential-mode-to-common-mode characteristics of the twisted pair on the differential signal is analyzed in the paper, and the electromagnetic emission generated by the automotive ethernet communication is compared when using different types of twisted-pair cables. A twisted pair cable with good performance can significantly reduce the electromagnetic emissions during communications.