Design, simulation, prototyping and experimentation of planar micro-strip patch antenna for passive UHF RFID to tag for metallic objects

Passive radio frequency identification (RFID) system operating in the ultrahigh frequency (UHF) band ranging from 860 MHz to 960 MHz is getting considerable attention in the recent years as it provides a long reading range, high data rate, and small antenna size. However, the passive UHF RFID tag does not work when it is directly mounted on metal objects. The performance of the passive UHF RFID tag is becoming increasing important for tagging metallic objects, in particular, in the warehouse applications. In this paper, a micro-strip patch antenna is proposed for the passive UHF RFID systems to tag metallic objects. The proposed design of the micro-strip patch antenna is supplemented by simulation and reading range measurement results. The prototype antenna measurements show a maximum reading range of 4.5 m and a reliable reading range of 1.89 m on metallic objects. The experimental results show that the prototype micro-strip patch antenna works very well on the metallic objects.