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As part of my university project I am trying to read NFC data (13.56MHz) at a longer range (~60 cm). I have already developed code that reads data from the card at close proximity, using libnfc and a standard USB based NFC reader.

I am facing the challenge to read data from distance. All the information I have seen out there seems to be a few years old with unsupported hardware.

My initial thoughts were to try to find a NFC reader that I could just plugged a bigger antenna, as you can do with 802.11 wireless technology...

I would appreciate some tips on how to achieve my goal, what type of hardware would I need? And could I still use libnfc and my code?

Cheers

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In summary,

  • When using a NFC standard loop coil antenna, sized about 4x4 cm, the theoretical maximum working distance is 20 cm. In practice, the range for reliable communication is much smaller, usually about 5 cm (4 times smaller).

How could you improve the range without tweaking the power level and sensitivity of the NFC devices (master/transponder and slave/tag),

Answering to your specific concern,

  • To achieve a practical 60 cm range, you may try to create a near field with a theoretical range several times bigger, for instance, 180-240 cm, for which you need a circular coil of about 2.5-3.4 meters in diameter.
  • You can also try a square shaped coil of equivalent area to the circular coil.

If you finally try, please, update or answer your own post and let us know about your findings.

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  • \$\begingroup\$ You may need to beef up the drive circuits to be able to couple useful energy into the larger coil. It may need more voltage compliance than the original coil even if somehow the inductance were to be identical it is unlikely that the resistance component would be the same as well. \$\endgroup\$ – KalleMP Feb 21 '17 at 8:53

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