For nfc reader can you suggest smd antenna

[PMK.1]

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[Travis Palmer]

Hello,

there are different types of antennas.

• Since the NFC IC is soldered on a PCB, a PCB antenna is a convenient way to do a good quality antenna.
• Another option is to do a wire wound antenna. Instead of traces done on the PCB, a wire is used to form a magnetic loop antenna.
• A more sophisticated (and expansive) way is to use a NFC ferrite antenna. There are several vendors (Maruwa, molex, muRata) doing such devices. They are often used in challenging applications (e.g. smart phones). https://www.st.com/en/partner-products-and-services/ferrite-flexible-sheet-antennas.html
• SMD antennas are used in very integrated products. where communication ranges of several mm read range are targeted. For example maruwa ferrite chip antennas MNA series: https://www.st.com/en/partner-products-and-services/ferrite-chip-antennas-mna-series.html#overview

For all types of antennas the self resonance frequency should be above 13.56MHz. (typically between 40MHz - 120MHz). The matching network is then used to make them resonating at 13.56MHz and therefore suite able for NFC. Also the Q-factor should be in a decent range, dependent on used technology and bitrate. AN5276 is providing a good overview about important antenna parameters.

Selecting the right antenna depends in most cases on the overall system and use-case. In an access control reader, a smd antenna could maybe also be used to read an ID1 tag, but the read range and cost might not be satisfying.

BR Travis