Electromagnetic Analyses of Near Field UHF RFID Systems

Environmental effects may seriously threaten the performance of UHF RFID systems and reduce the rate of successful reading; many applications aiming at the so-called item-level tagging (ILT) can be therefore compromised. In order to preserve the reliability of the tag acquisition the so-called near field (NF) UHF RFID has been recently considered. In this paper, the main properties and the performance of NF UHF RFID systems are investigated by means of electromagnetic analyses based on both theoretical evaluations on simple but representative radiating elements and measurements carried out also on real UHF RFID devices.