Filter and Grounding Solutions for Limiting Radiated Emission of a PCB with an Attached UTP Cable

This paper provides a methodological approach for predicting the radiated emission from a PCB with an attached UTP cable, supported by simulations. First, the sources of emission are analyzed and simple equivalent circuits for SPICE simulations are provided. The concept of filtering and grounding for emission reduction are introduced and a discussion on how to use them in practice is provided. Second, 3D numerical software is used to quantify the effectiveness of several fixes for an isolated PCB located in a metallic enclosure or with a chassis.