Radiated emissions and signal integrity of printed circuit board microstrips

EMC compliance is an important requirement for electronic systems. Radiation from printed circuit board traces can be a significant contributor to the EMC performance of electronic systems and needs to be taken into account in the design process. This is especially true in high speed digital system realised on one or more printed circuit boards. Another important consideration in the design of high speed digital systems is the signal integrity of interconnections. Signal integrity is managed mainly by selecting the type of termination and the transition time of the signal transferred over an interconnect. Empirical data suggests these factors also affect emission from the interconnections and cross-talk with other interconnections. This paper will provide models for two methods of termination for signal integrity management together with their associated radiated emission. A number of examples will be presented to illustrate the impact of the key parameters with the aim of identifying combinations that are good both from the signal integrity perspective as well electromagnetic compatibility.