Field Guide · concept

Also known as: NFC

Near-field communication (NFC) is a short-range wireless technology that lets two devices exchange small amounts of data when held within a few centimeters of each other.1

phone · NFC coil passive tag / card 13.56 MHz magnetic field ≤ ~4 cm · field powers the tag
NFC works by inductive coupling: the phone's coil radiates a 13.56 MHz magnetic field that, within a few centimeters, induces current in a passive tag's coil — powering it and carrying data both ways without the tag needing its own battery.

Overview

NFC operates at 13.56 MHz and grew out of RFID. Its very short range is a feature, not a limit: a tap is deliberate and hard to eavesdrop on. A device can act as a reader (scanning a tag or card), a tag (presenting credentials), or in peer-to-peer mode.

An NFC controller in the SoC, wired to a small loop antenna, can even power a passive tag through its magnetic field, so unpowered stickers and cards work with no battery of their own. The mobile OS exposes the controller to apps for payments and pairing, usually behind a secure element that holds payment credentials.

NFC vs other short-range radios

NFC deliberately trades range and speed for intimacy and simplicity:

Property NFC Bluetooth Wi-Fi
Range ~4 cm ~10 m ~30 m+
Data rate ~424 kbit/s 1–3 Mbit/s 100s Mbit/s
Pairing Instant tap Discovery/pair Join network
Powers passive device Yes No No
Typical use Pay, ticket, tap-pair Audio, peripherals Internet, streaming

Its slowness barely matters, because NFC carries only tiny payloads — a token, an ID, or a handoff that then continues over a faster radio.

Where it fits

NFC is the technology behind tap-to-pay on a smartphone or smartwatch, transit cards, and instant Bluetooth pairing. It complements an eSIM and the longer-range radios in a device: where the cellular and Wi-Fi radios reach across networks, NFC handles the intimate, intentional “touch here” interactions of everyday mobile use.

Sources

  1. Near-field communication — Wikipedia, on NFC technology and uses. 

See also