RFID Journal Glossary of Terms
Near-field communication:
RFID
reader antennas emit electromagnetic radiation (radio waves). If an
RFID tag is within full wavelength of the reader, it is sometimes said to be in the "near field" (as with many
RFID terms, definitions are not precise). If it is more than the distance of one full wavelength away, it is said to be in the "far field." The near field signal decays as the cube of distance from the
antenna, while the far field signal decays as the square of the distance from the antenna. So passive RFID systems that rely on near-field communication (typically low- and
high-frequency systems) have a shorter
read range than those that use far field communication (
UHF and
microwave systems)