Design of a dipole tag antenna enclosed by a short-stub for UHF RFID application

Radio frequency identification (RFID) systems have been rapidly developing in the ultra high frequency (UHF) band due to the advantage of long recognition distance. To reduce the production cost, a tag antenna should be directly matched to a tag IC including a charge capacitor which compensates the large conductive reactance of a tag IC. In addition, the power from an antenna can be maximally delivered to a tag IC when an antenna impedance is conjugately matched with that of tag IC. However, folded dipole antennas, slot antennas, and meander antennas, which are commonly used for RFID tags in UHF band, do not have enough large inductive reactance for conjugate matching to a tag IC. Thus, new type of RFID tag antenna having large inductive reactance is necessary. In this paper, a UHF band RFID tag dipole antenna enclosed by a short-stub is proposed. The proposed antenna has a compact size (64.1 mm times 17.8 mm) and large inductive reactance.