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Working on an NFC application (NFC tag) and it looks like the NFC antenna will be located off-board. This is a sticker type of antenna.

The concern that I am possibly having is that I need to run some wires from the NFC IC to the antenna, and I fear this may be a problem for FCC / CE testing as the 13.5MHz gets radiated along the wires. The length of the wires/cables is currently not known.

To have a high chance of success in passing, what can I do (cost-effectively) to increase my chances of success?

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  • \$\begingroup\$ Questions here need to be more specific, open-ended ones don't really fit. \$\endgroup\$ – Chris Stratton Oct 19 '20 at 16:37
  • \$\begingroup\$ Naturally an NFC reader can't radiate 13.5 MHz without radiating 13.5 MHz, so really you need to consider the ways in which you are / are not allowed to do so; eg, why would you be allowed to do so from the antenna but not the antenna lead? (there actually are obscure rule subparts where a feedline counts as an antenna) What are the possible performance issues? Should you consider some sort of shielded feedline? Should you move the NFC reader electronics closer to the coil antenna and send only power and baseband data in betweeen? \$\endgroup\$ – Chris Stratton Oct 19 '20 at 16:39
  • \$\begingroup\$ @ChrisStratton I don't know how to be specific in this case. New area for me. My concern is possible failure on FCC / CE testing related to a cable of unknown length. Would I need a filter ? emc filter ? shielded cable ? I don't know what to ask here. \$\endgroup\$ – efox29 Oct 19 '20 at 16:40
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    \$\begingroup\$ If it's a tag then it is powered by an overwhelming external magnetic/electric field so shouldn't this be the biggest source of interference and any slight modifications to that field carried by the wires from your tag will be incidental. Hi by the way! \$\endgroup\$ – Andy aka Oct 19 '20 at 16:40
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    \$\begingroup\$ @Andyaka lol hi ! \$\endgroup\$ – efox29 Oct 19 '20 at 16:58
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The sticker type loop antenna may be fed through a 1.13 mm micro coaxial cable.

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