A new UHF anti-metal RFID tag antenna design with open-circuited stub feed

A new UHF RFID tag antenna used on the surface of a metallic object is proposed in this paper. In practical RFID applications, metals appear in many occasions. However, the UHF band is very sensitive to metal. When the tag antenna is near a metal, its impedance matching, radiation efficiency and directivity change and the reading distance is reduced so quickly that it cannot work. Therefore, it´s necessary to employ some special handling or use a special tag so that it can be applied on the metal surface. After several rounds of design optimization and experimental validation, the designed tag antenna can work in the 920 MHz frequency band and is able to maintain a good performance on the metal surface. What´s more, it has some advantages such as planar structure, small size and low cost. The proposed tag antenna provides an effective solution for metal identification applications in the UHF frequency band, which is validated by simulation results and practical test.