Use of transmission lines as near field antenna in UHF RFID

in this paper the use of simple transmission lines as “near-field antenna” for Ultra High Frequency (UHF) Radio Frequency IDentification (RFID) applications is proposed. The limitation of the reading/identification zone to the “near field” region of the antenna is a challenging problem for UHF RFID application. Several solutions have been proposed during past years but most of them are complicate and expensive in the final implementation. In this paper a very simple solution based on a transmission line concept will show that is possible to achieve a limitation of the reading zone in a simple and effective way by using very simple “antenna” or better to say: “coupling mechanism system between RF signal generated by RFID reader and UHF RFID Tag”.