RF Power Amplifier Design

NFC-forum.org tells operating distance is a few cm.
This suggests it works by inductive coupling (magnetic fluctuations) rather than transmission of photons (electromagnetic waves).

Wireless charging is one role for near-field (and a frequent topic at this forum). Source is not a conventional radio transmitting antenna but a coil of wire carrying sine waves. 13.56 MHz appears to be standard.

The receiver is a nearby resonant circuit, tuned to the transmitting frequency. Usually a coil of wire paired with a capacitor.

Data communication is another role. For do-it-yourself I suspect signaling via ASCII code (modem-style) is feasible.

I believe far-field refers to photon transmission (electromagnetic waves). It's difficult to distinguish whether the same amplifier that creates near-field also transmits far-field.