An NFC tag looks like a single object — a sticker, a card, a keychain. Pull it apart and it is really a stack of thin layers laminated together, each doing one job. Knowing what those layers are makes it much easier to pick the right tag, because the part everyone fixates on — the memory chip — turns out to be the smallest and least decisive piece.
The four layers
Most flat NFC products — stickers, cards, paper tags, inlays — share the same basic construction. From the surface you tap down to the surface it sticks to:
- Face / overlay — the printable top layer (paper or PET film) that carries the artwork, logo, or instructions. Purely cosmetic and protective; it does nothing electrically.
- Antenna — a flat coil of copper or aluminium, etched or printed onto a carrier film and tuned to the 13.56 MHz NFC frequency. This is the part that actually picks up the phone’s field and powers the chip.
- Chip (IC) — the NFC tag IC, such as an NTAG213, NTAG215, or NTAG216, bonded across the antenna’s two terminals. It holds the memory and the unique ID. Physically it is a speck, often under a millimetre across.
- Substrate & adhesive — the PET or paper layer that carries the antenna and chip (together called the “inlay”), plus the pressure-sensitive adhesive and release liner that let it stick to a surface.
The antenna does the heavy lifting
NFC tags are passive — they have no battery. When you bring a phone close, the phone’s NFC field induces a current in the antenna coil, and that current is what wakes the chip up. So the antenna’s size, shape, and tuning largely determine how far away the tag will read and how reliably it works on a given surface.
This is why two tags with the exact same NTAG chip can perform very differently. A large, well-tuned antenna reads from further away; a tiny one needs a near-touch. Put a standard tag on metal and the metal detunes the antenna and kills the read entirely — which is why on-metal tags add a ferrite shielding layer between the antenna and the surface.
| Layer | Job | What it affects |
|---|---|---|
| Face / overlay | Artwork and protection | Looks, durability, printability |
| Antenna | Harvests the phone’s field | Read range, surface and on-metal behaviour |
| Chip (IC) | Stores the ID and memory | Memory size, locking, password protection |
| Substrate / adhesive | Holds it together and on | Form factor, flexibility, where it sticks |
Where memory actually sits
The memory — 144 bytes on an NTAG213, 504 on a 215, 888 on a 216 — lives entirely inside that one tiny chip. It is a real consideration if you need to store data offline on the tag, but for the common case of storing a short URL, even the smallest chip has room to spare. The layers that decide whether the tag is pleasant to use in the real world are the antenna and the substrate, not the memory.
That is also why the modern way of deploying NFC barely depends on the chip you choose. If the tag only stores a short URL and the real content lives on a server, the chip is just an identifier — and the antenna and build quality matter far more than capacity.
The takeaway
The chip gets the attention, but the antenna decides whether the tag works.
When you are comparing NFC tags, look past the chip name first. Ask about antenna size and read range, surface and on-metal compatibility, and build quality. Then pick a chip with enough memory for your payload — which, for URL-based deployments, almost always means the smallest and cheapest one will do.