ABSTRACT
All electrical circuit boards are designed to enable and even promote the flow of electrons in order to achieve some performance goal. The flow of current along a closed route generates a magnetic field that extends outward and perpendicular to the current flow. Electromagnetic interference (EMI) arises when there are close electronic elements or signal channels inside this field. Controlling the quantity of EMI is a fundamental concern that must be appropriately addressed in many Printed Circuit Board Assembly (PCBA) designs, particularly high-speed boards. An EMI filter design is a popular technique for boards having radiator-classified components. Although filters are effective, as a circuit board designer, you will most likely need to use extra PCB design recommendations for decreased EMI. The majority of PCBAs are not the sole electronic or electrical devices contained within a product. As a result, before delving into single-board EMI issues, it is useful to have a macro- or system-level understanding of the EMI problem. Just as electromagnetic energy radiates from a single component, conductor, or trace, it also radiates from the board itself into the surroundings; if you haven’t done so previously, set a gauss meter adjacent to a PCB to acquire a reading. When many boards are in close proximity, electromagnetic compatibility, or EMC, becomes critical. EMC may be conceived of as attaining an acceptable harmony or balance between electromagnetic components such that interference is minimized or at least low enough not to severely impede normal functioning. Unfortunately, total EMI removal is not yet attainable; however, acquiring EMC is. EMI, which is defined as any interference from an electromagnetic source, is commonly used to refer to interference on a single PCBA. This classification is enough for analysing the problem, as reducing EMI on and off a circuit board adds to the EMC of the environment in which the board functions. The purpose of this chapter is to give design principles for creating printed circuit boards for EMI and EMC investigation.
