Analysis and Assessment of the Common Mode Termination for Automotive Ethernet 1000BASE-T1

Abstract

In this work the currently proposed common mode termination (CMT) for 1000BASE-T1 is analyzed analytically. Especially the complex mixed mode scattering parameters of this circuit are calculated as a function of frequency. In addition, simulations and measurements are performed using a simple printed circuit board. All in all, the obtained results show a very good agreement. Based on this, an evaluation of the CMT is finally performed. It can be stated that the current circuit design reduces the common mode only to a very limited extent.