I need to build an application to detect an NFC antenna without an NFC passively powered chip.

As we know, we can detect an NFC tag by powering the NFC chip inside this tag. It will then broadcast its ID to the mobile using an NFC data transmission field.

What if I build an antenna with some kind of load such as a resistor; with this I can detect that there is a power drain caused by the NFC adapter in the mobile. As result I will be able to detect that there is an NFC antenna in the back of the mobile. Any ideas?

  • \$\begingroup\$ Why do you want to do this? \$\endgroup\$ Apr 25, 2021 at 11:56
  • \$\begingroup\$ I need to trigger the NFC inside the mobile and then detect this trigger \$\endgroup\$
    – user176024
    Apr 26, 2021 at 12:11

1 Answer 1


I used a NanoVNA recently and with that I could detect if there was an RFID antenna and if there was a RFID card in the field, but I don't think that is what you want. Nevertheless, it illustrates that you can have a sweep frequency generator and detect the resonance.

  • \$\begingroup\$ Is there any SDK to use it ib detect the antenna inside NFC field \$\endgroup\$
    – user176024
    Apr 24, 2021 at 23:05
  • \$\begingroup\$ SDK for what? All mobile phones are not created equal. It is unclear what you want to achieve. \$\endgroup\$
    – Kartman
    Apr 24, 2021 at 23:11
  • \$\begingroup\$ I mean is there any way to detect programmatically that there is a coil inside the mobile NFC field \$\endgroup\$
    – user176024
    Apr 24, 2021 at 23:14
  • \$\begingroup\$ you have to be able to detect it by turning an analog knob first ... then you can add digital control \$\endgroup\$
    – jsotola
    Apr 25, 2021 at 0:14
  • \$\begingroup\$ Turning an analog knob, How can I achieve this ? \$\endgroup\$
    – user176024
    Apr 26, 2021 at 12:15

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