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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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  • \$\begingroup\$ Are you trying to read a passive tag? \$\endgroup\$
    – Andy aka
    Commented Feb 15, 2015 at 10:09
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    \$\begingroup\$ this is the opposite of electronics.stackexchange.com/questions/145461/… \$\endgroup\$
    – user16324
    Commented Feb 15, 2015 at 10:25
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    \$\begingroup\$ sounds a bit strange for a university project. \$\endgroup\$
    – Benjoyo
    Commented Feb 15, 2015 at 10:27
  • \$\begingroup\$ The report "How to Build a Low-Cost, Extended-Range RFID Skimmer" by Ilan Kirschenbaum and Avishai Wool explains how to build an NFC reader that is able to read NFC card from a 25cm distance using 40cm antenna. eprint.iacr.org/2006/054 \$\endgroup\$
    – FaST4
    Commented Dec 2, 2021 at 8:39

1 Answer 1

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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
    Commented Feb 21, 2017 at 8:53
  • \$\begingroup\$ I was looking for a bigger antenna design. A coil around the 7-inch display. I expect this can read tags anywhere around the screen. Based on this answer, the NFC antenna can be much bigger. If I don't want a long distance reader. Can I make tag reader that reads any tag on the 7 inch screen? \$\endgroup\$
    – hurelhuyag
    Commented Apr 23 at 1:36

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