EMC Question of the Week: June 8, 2026
Small unconnected copper dots or diamonds on the outer layers of a printed circuit board are an example of
- ground fill
- via stitching
- guard posts
- thieving
Answer
The best answer is “d.” Thieving is the addition of plated pads across the surface of a printed circuit board. Their purpose is to provide a uniform distribution of copper across the outer layers to make the plating thickness more uniform. Because they are small and unconnected, they generally have no impact on EMC or signal integrity. Nevertheless, it is best not to locate them directly above or adjacent-to controlled impedance traces.
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