Embedded passive UHF RFID seal tag for metallic returnable transit items

In this paper the novel passive UHF RFID seal tag for metallic returnable transit items (RTI) is presented. The tag design exploits the metal structure of RTI. Enhanced security encoding based on MD5 hash and AES algorithm is also presented, which enables authentication without online network connection. Up to 9 m theoretical read distance was obtained with 19 mm × 20 mm × 57 mm size tag. 100% read rate was reached with the stack of ten RTI containers in a 3.5 m wide RFID portal.