Broadband UHF RFID Tag Antenna with Multi-Bent Dipoles

In this paper, a broadband UHF RFID tag is proposed. By introducing a coupling loop and four bent dipoles, two resonant modes are excited in UHF RFID band, which results in a total 194 MHz (806MHZ-1GHz) 3dB operational bandwidth. It covers the entire UHF band (860 MHz-960MHz). This tag antenna exhibits a dimension of 73.8 mm × 34.4 mm × 0.5 mm (0.222 λ × 0.105 λ × 0.0015 λ). It is fabricated on a low-cost FR4 PCB substrate. The measured reading distance at 915MHz is 9.6 m, when EIRP is equal to 3.16 W.