Compact UHF near-field RFID reader antenna

A compact dual open-loops antenna with bandwidth enhancement is proposed for near-field operations in the ultra-high frequency (UHF) band, which is able to generate a strong and uniform magnetic field in a near-field zone of the smaller open-loop. The two open-loops with individual half-wavelength perimeters are etched on each sides of FR4 printed circuit board and used for widening bandwidth. The fabricated compact antenna with an overall size of a dimension of 60 × 60 × 0.8 mm³, achieves an interrogation zone of 50 × 50 mm² with good impedance matching and uniform magnetic field distribution over the bandwidth of 888-932 MHz. The measured reading distance of the proposed antenna is up to 130 mm for near-field applications, and it confirmed that the antenna is suitable for handheld radio frequency identification (RFID) reader applications.