A Magnetic Coupling Dipole for UHF Near-Field RFID Reader

In this paper, a novel printed-folded dipole for ultra-high frequency (UHF) near-field (NF) radio-frequency identification (RFID) reader using magnetic coupling is proposed. The strong and uniform magnetic field is excited by two opposite-directed currents (ODCs). The folded dipole is printed on an FR-4 substrate with the scale 32 cm × 20 cm. The bandwidth of the antenna ranges from 826 to 853 MHz. When the transmit power of the proposed antenna is 17 dBm, the reading area can be managed to 35.3 × 24 cm² on the surface for Impinj F43 tag, and the reading distance is around 5 mm. For the case of ceramics ISO1800-6-C tag, and at the same time, the reading area increases to 58 × 42 cm², and the reading distance is around 77 mm at the center of the antenna. Both simulations and measurements show that the proposed antenna can provide a broad reading area with a very low transmit power of 17 dBm.