Definition

Radio-Frequency Identification (RFID) uses electromagnetic fields to automatically identify and track tags attached to objects. RFID systems consist of tags (with antenna and chip) and readers. Tags can be passive (powered by reader's RF field), active (battery-powered), or semi-passive. PCB technology is used for RFID antennas on both rigid and flexible substrates. Operating frequencies include LF (125-134 kHz), HF (13.56 MHz), UHF (860-960 MHz), and microwave (2.45 GHz). Antenna design requires precise impedance matching and careful material selection for the target frequency.