Fast and Accurate Estimation of Radiated Emission from Printed Circuit Board Using Common-mode Antenna Model Based on Common-Mode Potential Distribution

The authors investigated common-mode potential distribution on printed circuit boards and propose a common- mode antenna model that consists of a common-mode excitation source and a common-mode antenna element. The antenna model is able to predict common-mode radiation from PCBs quickly and accurately because it focuses only on common-mode radiated emissions. This paper applies the model to a rectangular printed circuit board with a signal trace bent at a right angle and discusses the superposition of common-mode excitation sources that result from common-mode potential distribution. In the model, the trace is divided into two straight elements at the corner to obtain the common-mode excitation source separately for each straight element. Superposing each source at each position enables a set of common-mode sources of the entire common-mode antenna model to be obtained. Simulations and measurements showed that the superposition of common-mode sources accurately predicts radiated emissions.