A novel magnetic coupling UHF near field RFID reader antenna based on multilayer-printed-dipoles array

In this paper, a novel ultra-high frequency (UHF) near field (NF) radio-frequency identification (RFID) reader antenna using magnetic coupling is proposed. The strong magnetic field utilized as the reading zone is produced by an NF antenna component, which is fabricated by three-layers PCB comprised of a four-way power divider and a dipole array. The four units of the dipole array are placed along the edge of a square and their feed resources have the same amplitude and phase. The proposed antenna has a compact size of 96 mm x 96 mm x 2 mm, and it resonances at 842 MHz. The bandwidth can meet China's Standard (840-845 MHz). Both the simulated and measured results show that the magnetic field generated by the dipoles array is strong and uniform, which makes the reader operate at a very low transmit power of 17 dBm to identify the tags on the surface of the reader. The antenna component can be integrated with the reader easily, due to the low profile and miniaturization design, and shows great reading performance.