Predicting EMC emissions from printed circuit boards using numerical modeling tools

Abstract

Most signals which cause emissions originate on the printed circuit (PC) board. Naturally, some of these signals are required for proper operation of the device, but often these required signals are coupled into areas where they were not intended and cause potential EMC emissions. Typical PC boards contain many traces which are closely packed together. This makes the analysis of potential emissions very complex and difficult. There is a need for automated prediction tools which divide the total PC board emissions problem into individual problems which can be analyzed quickly and accurately. While there is not one modeling tool which can predict emissions from a complete circuit board CAD file, there are many applications for modeling of emissions from PC boards. Each specific cause must be considered separately, and then modeled individually. This is likely to require a number of different modeling tools and techniques. This analysis is likely to require the finite-difference time-domain (FDTD), the method of moments (MoM) and the partial element equivalent circuit (PEEC) modeling techniques, at different times, for different applications.