NFC Antenna Basics: Design, Testing, and Vendors

This page covers NFC antenna basics, describing loop antenna design used as RFID or NFC antenna. It also touches upon NFC antenna testing and provides a list of vendors/manufacturers.

The antenna used in NFC devices, such as tags and readers, typically has a loop structure. It operates at a frequency of 13.56 MHz.

NFC antennas are widely used in NFC-compliant mobiles, NFC payment readers, wallets, ID scanners, data loggers, ticketing systems, and various other applications. As we know, when an electric current passes through a conductor, it produces a magnetic field. Moreover, a change in the magnetic field produces an electric field.

Conductor loops are used to generate electromagnetic fields in NFC devices such as readers and tags. The strength of the magnetic field decreases with respect to the distance from the loop wire.

Loop Antenna Design used as NFC Antenna

Figure 1: NFC Antenna

Figure 1 depicts an NFC antenna, its matching network, EMC filter, and NFC tag/reader electronics. The EMC component functions as a Low Pass Filter, eliminating second and higher-order harmonics. It also performs impedance transformation.

Figure 2: NFC Antenna Equivalent Circuit

Figure 2 illustrates a loop coil antenna used in NFC reader and tag designs. It shows the equivalent circuit of the NFC antenna. As shown, it comprises L, R, and C components. Here, L is determined by the number of turns of the antenna coil, R by the diameter and length of the antenna wire, and C by the distance between antenna wires and the number of turns.

NFC Antenna Testing

The following tests are performed to check the NFC antenna’s performance:

• ISO/IEC 14443 tests: Tests carried out for PICC/PCD, type-A and type-B for bit rates 106, 212, 424, 848 kbps.

• NFC Forum tests: Defines test cases for NFC Forum devices such as P2P, reader and card modules, used for mobile phones. NFC compliance certification is available and is mandatory for NFC forum devices.

• EMVCo Tests: Tests carried out for PICC/PCD, type-A/B, done only for data rate of 106 kbps.

RFID or NFC Antenna Vendors/Manufacturers

The following are the NFC Antenna Vendors/manufacturers:

• Pulse Electronics
• TE Connectivity
• AMS AG, Austria
• Amphenol MCP
• Abracon Corporation