I can find recommended inductance for NFC which seems to be 4.7uH which I guess will provide communication up to 5cm with maximum power and maximum data speed, but I cannot find minimum Inductance for NFC for:
- Smaller distances, like actual contact to a few mm
- Less power requirements (i.e not using NFC for charging)
- Lower data speeds (i.e only transmitting a small amount of data or where slow speed is acceptable)
Note that since the antenna is so small you'll need to put the tag right up against the device that's reading it
So is having to hold this tag close to reader the only downside?