What is EMC Testing for PCB? What are the design considerations?
Editorial Team - EMC Directory
EMC, or electromagnetic compatibility, refers to a printed circuit board's ability to function properly within an electromagnetic environment without generating electromagnetic or radio frequency interference in nearby devices. EMI can negatively affect system performance when the operating region of a device deviates from the defined standards or conditions. EMC ensures that the PCB is immune to EMI under the defined operating conditions.
A PCB is considered to have electromagnetic compatibility when it doesn't cause interference with other systems and devices, isn't affected by emissions from other systems, and doesn't disrupt its own functioning. Designing a PCB for EMC compliance requires a change in the thought process, where one needs to see the relationship between "noise" in the PCB layout, a "radiator" as defined in EMC standards, and any area where noise could couple out of the system through a cable. Early recognition of this can help spot potential EMI/EMC errors before sending a design for testing.
Various modeling techniques are used to measure electromagnetic emissions in an electronic system, with computer simulation being the fundamental approach in EMC analysis. Accurate measurement of essential parameters is achieved through integration techniques. Steps such as finite difference time domain modeling are implemented to measure the frequency response of the common-mode current during high voltage applications. Factors like current-mode antenna impedance and the distributed circuit constant are considered while evaluating the common-mode current, along with the electric coupling between the power plane and the ground plane.
To ensure that a PCB meets EMC standards, the following design considerations should be taken into account:
The number of layers in a printed circuit board (PCB) can affect the electromagnetic compatibility (EMC) performance of the PCB. Generally, a 4-layer PCB can offer better EMC performance than an identical 2-layer PCB due to the following reasons:
Overall, a 4-layer PCB can offer better EMC performance than an identical 2-layer PCB due to the improved signal integrity, power delivery, and reduced radiated emissions. However, it's essential to consider other factors such as the type of components, their placement, and the design of the board, which can also affect EMC performance.