What’s NFC tag?

NFC Tags are electronic circuits having an antenna and a small amount of memory, which start a communication when one gets near to, some centimeters, from, an active NFC device. The reader will communicate with the tag, decoding the signals and then being requested to do something. Some tags are rewritable, so that the readers can update data on it.

Typically, tags act in the passive NFC mode, being fed by a magnetic field. Once they are read by the NFC reader, they provide the mobile phone or the NFC reader with instructions, aiming at performing some action. Therefore, these tags can be used by any device and are able to transfer data or instructions on them through embedded NFC. The feature offered is similar to the one currently found on mobile phones, however, instead of a two-way communication, this communication takes place from the tag to the receiving device.

Building of a NFC Tag

NFC Tags are built by attaching the NFC chip to the small antenna, typically made of a very thin aluminum. This one is fixed to the plastic base (plastic thin sheet) in order to keep it held together.

What are the types of tags?

There are four basic types of tags, assigned from 1 to 4 where each one has a different format and capacity. These NFC tags types formats are based on A and B types ISO14443 standard (international standard for contactless smartcards) and Sony FeliCa compliant with ISO 18092 norm (passive communication standard mode).

The different NFC tag types definitions are the following:
Tag 1 Type: based on ISO14443A standard, for both reading and rewriting purposes, where the users can set the tag to become read-only. Its memory availability is of 96 bytes, being able to store a website URL or another small quantity of data. Nevertheless, the memory size is expandable up to 2 kbyte. The NFC tag communication speed is of 106 kbit/s.
Tag 2 Type: also based on ISO14443A standard, for both reading and rewriting purposes, where the users can set the tag to become read-only. The basic memory size of this type of tag is of only 48 bytes, but it's expandable to 2 kbytes and the communication speed is of 106 kbit/s.
Tag 3 Type: based on the Sony FeliCa system, its current memory capacity is of 2 kbytes and the data communication speed is of 212 kbit/s. This type of NFC tag is usually employed in complex applications, being more expensive.
Tag 4 Type: it’s defined to comply with A and B ISO14443A standards. These NFC tags are factory-set and may be read/rewritable, or read-only. Its memory capacity may be of up to 32 kbytes and the communication speed is between 106 kbit/s and 424 kbits/s.

NFC Chips

In the core of each NFC tag, there's a “chip” or ‘IC’ (integrated circuit) NFC, these electronic devices store their information and control how they can be accessed. There are several types of NFC Chips, each one having its own characteristics, which may vary in the amount of data they store, whether they are read-only or rewritable (168), the chip performance, and other special characteristics. The main aspect determining the NFC tag choice is the memory amount that it has in its chip. Examples of NFC Chips are shown below:

Ultralights (UL): Good for telephone number or short URL (64 bytes);
Ultralight Cs (ULC): Has a slightly higher data storage capacity and is good for a long URL or a small contact card (192 bytes);
Standard 1K: Able to store more data for a large contact card, however, it’s more expensive (1024 bytes);
NTAG203: Just like ULC, but it’s a new type of chip with more responsiveness (168 bytes);
Anti-Metal Tags: May be stuck to metallic surfaces.

How to choose the most suitable tag?

NFC Tags may be incorporated to products, stickers, business cards, and wristbands, etc. Tags variation is partially due to the size and conception of the very antenna, but also to the building of plastic layers in its format and adhesive providing different tag variations. When it comes to acquiring a tag, in addition to the NFC chip choice, the NFC tag choice also comprehends:
  • Storage capacity;
  • Antenna size;
  • Building (wristband, keychain, adhesive, magnet, pen, etc.);
  • Whether they are going to be used indoors or outdoors;
  • Optional layer for it to be used on metal.

Last edited Aug 6, 2014 at 9:17 PM by brmontei, version 7