RFID system exploiting large metal objects as near field UHF RFID antennas

Abstract

In this paper, we demonstrate that a long thin metal structure can act as as a near-field antenna for a passive UHF RFID system comprising a metal mounted tag on the structure and a direct electrical feed onto the structure for both transmission of reader to tag signals and reception of the tag response. It is shown that a conventional metal mounted tag can be read up to 30 m away from the feed point on the structure far exceeding the maximum far field free space range of the tag mounted on metal.