RFIDs

RFID stands for radio-frequency identification and refers to wireless systems that identify and track objects using electromagnetic fields. A typical RFID setup includes tags attached to items, readers that interrogate tags, and a back-end database or middleware that stores the collected data. Tags may be passive (powered by the reader’s field), active (with an internal battery), or semi-passive (battery-powered for sensors but not for signaling).

RFID operates across several frequency bands. Low frequency (LF, about 125–134 kHz) and high frequency (HF, 13.56 MHz) tags often use near-field inductive coupling and are common in access control and animal tagging. Ultra-high frequency (UHF, 860–960 MHz) and microwave (2.45 GHz) tags use far-field backscatter and generally offer longer read ranges for inventory and logistics. Standards include ISO/IEC 14443 and 15693 for contactless cards and EPC Gen2 (ISO 18000-6C) for many UHF tags.

In operation, a reader emits a field to power a passive tag or to communicate with an active tag, which returns an identifier and optional data. Anti-collision protocols allow reading many tags quickly. Security varies by application, with some tags supporting encryption and authentication and others offering only basic identifiers; privacy concerns and regulations may enable deactivation at checkout.

RFID is widely used in inventory and asset management, library systems, access control, livestock and vehicle tagging, and certain payment applications. Benefits include non-contact identification and automation, but challenges include cost, interference, and the need for data governance.