NFC on metal?
ap0l0 wrote 11/25/2020 at 07:23 • 0 pointshello,
Noob question but needing consulting from an expert about NFC and its limitations. I assume the project wont take many hours since it’s just brainstorming ideas. I created an offering at upwork but not having much luck, too many people applying but hard to identify who would work. Anyway, thanks in advance!
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Sorry, no, I'm just an electrical engineering student who occasionally tinkers with this sort of stuff, and I know from my Electrical Motors class that conductive surfaces and high-frequency magnetic fields do interesting stuff.
But I'm glad you found my response useful
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To add some context, the idea is to make an NFC antenna work below a metal cover or similar material (carbon fiber?)
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I'm not sure if that will work well, sorry.
NFC uses a oscillating magnetic field to transfer both a little bit of power to the receiving chip, as well as establish a data communication channel.
By adding a metal cover, you will essentially dampen and swallow a lot of this magnetic field before it even reaches the receiver coil, and it might inhibit the usual way with which NFC shares data (which is by modulating the 13.56MHz frequency magnetic signal). At this high frequency, any metal component in the path of the magnetic field will experience induction and thusly add losses. Actually, any conductive material will do this, including carbon fiber.
https://www.reddit.com/r/NFC/comments/2xkom7/nfc_tag_behind_aluminum/
This seems to hold some good information too, and a bit of google searching gives similar results.
Then again, a lot of the modern smartphone cases seem to be metal based, and they still let WiFi and Radio Signals through, so I might be very wrong.
It might be possible to reduce losses somewhat by doing something similar to what electric motors do, by using a plated/segmented material that does not provide enough area for larger current loops. But this would be very expensive compared to using a cover material that simply is non-conductive.
If anyone has a bit more knowledge about this I would love to see it - this was just a writeup of my initial thoughts, but it does leave me quite curious :>
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Hi @Xasin , amazing response, thanks for the time. Are you an NFC expert? Looking for some consulting hours with an electrical engineer to help us define some products capabilities.
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