Design of a compact wideband UHF RFID tag antenna

In this paper, we propose a compact wideband tag antenna for UHF RFID systems. To miniaturize the size, an inductive coupled parasitic element is used between the two lines of a folded dipole antenna. The proposed antenna has a π-matching structure for wideband conjugate impedance matching with the impedance of a tag IC. The overall dimension of the proposed tag antenna is 23.5 mm × 34 mm and it has a gain higher than 2 dBi over the entire Korean UHF RFID band. The size of the tag antenna is about 30% of that of other small RFID tag antennas. In spite of its small size, the proposed tag antenna yields superior gain and wide bandwidth.