Prediction of radiated emissions from high‐speed printed circuit board traces using dipole antenna and imbalance difference model

Abstract

Ahmed Mohammed Sayegh aResearch Center for Applied Electromagnetics, Universiti Tun Hussein Onn Malaysia, Batu Pahat, Johor, Abstract: The ever-increasing clock speeds o n printed circuit board (PCB) have enhanced PCB traces t o become efficient radiators o f electromagnetic energy. Conventionally, the radiated emissions (REs) o f electrically short PCB traces are estimated using expressions developed based o n electric/magnetic dipole antenna. In this study, a novel method was proposed t o estimate RE f r o m electrically long PCB traces. In this method, the differential-mode (DM) RE was estimated using the transmission-line theory and dipole antenna model, whereas the common-mode (CM) RE was computed b y a combination o f imbalance difference model and a dipole antenna. Conceptually, the electrically long trace was chunked into multiple electrically short segments and the fields o f each segment were superimposed t o obtain the net radiated fields. Additionally, closed-form expressions were derived t o estimate the D M REs f r o m electrically long PCB traces based o n dipole antenna model. On the other hand, C M RE was predicted b y line integration o f CM current distribution which was approximated using imbalance difference model and asymmetrical dipole antenna model. The effectiveness o f the proposed method was verified using compact single-sided PCB b y comparing the computed results with the measured results taken in a semi-anechoic chamber, and a good agreement with accuracy more than 90% was observed for upper bounds of the REs.