At what frequency do PCB traces start to act as antennas?

Just interested in PCB design. I am wondering whether PCB traces start to act as antennas at some frequency. Anybody knows?

November 14, 2023

Frequencies where the length of the trace is comparable to 1/10th of the wavelength of the wave in air is a decent rule of thumb I’ve heard.

However, you should still be watching out to avoid accidental antenna problems.

Avoid ground loops. Use a single point as ground (usually a plane at the bottom of the PCB), and don’t route the ground of one point through the ground at another point. Ground loops can cause really big signal integrity problems.
Where possible, use differential signaling — that is, a pair of wires or traces — to send signals, and receive them with differential amplifiers.

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Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

Oliver Smith

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At what frequency do PCB traces start to act as antennas?

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