RFID

RFID, or radio-frequency identification, uses radio waves to identify and track objects. An RFID system typically includes tags attached to objects, readers that emit radio energy and capture responses, and a backend data processor.

Tags are small devices with an antenna and an integrated circuit. Passive tags have no power source and draw energy from the reader's signal; active tags have a battery and can initiate transmissions; semi-passive tags have a battery for the chip but rely on the reader for communication.

RFID operates across several frequency bands. LF around 125 kHz and HF at 13.56 MHz enable near-field use; UHF bands around 860-960 MHz enable longer reads; microwave RFID uses about 2.45 GHz. Standards such as ISO/IEC 14443 and 15693 cover smart cards and inventory use, while ISO 18000-6C (EPC Gen2) governs passive UHF tags in supply chains.

Applications span inventory and asset tracking, access control, product authentication, library systems, livestock tagging, baggage handling, and contactless payments.

Advantages include non-line-of-sight reading, rapid bulk reads, and operation without human intervention. Limitations include tag cost, interference from metal or liquids, encryption and privacy concerns, and regulatory constraints on radio power and frequency use.

Security and privacy considerations include the potential exposure of a unique identifier; some systems implement encryption, authentication, and deactivation features. Measures such as shielding, selective reading, and data minimization are commonly employed.

History and standardization trace RFID origins to transponders used in World War II, with development through the late 20th century. The EPCglobal consortium and GS1 promoted interoperable RFID for supply chains, contributing to widespread adoption since the 2000s.