Experimental Performance Evaluation of Passive UHF RFID Tags in Electromagnetically Critical Supply Chains

Radio Frequency Identification is going to play a very important role as auto-identification solution for many application scenarios, where item-level tagging and high performance are crucial. In such a context, the use of passive Ultra High Frequency (UHF) tags is strongly suggested but, unfortunately, general-purpose commercial tags could not meet all the requirements in presence of critical operating conditions, including the presence of metals and liquids, the misalignment between tag and reader antennas, and the need of multiple reading of tags. In this paper, the main features that a UHF tag should own to work properly in the whole supply chain are presented. A tag, named below Enhanced tag, satisfying all the individuated requirements has been also realized and validated in a controlled test environment simulating the pharmaceutical supply chain. Tests have been focused on the above-mentioned critical conditions. The performance of the Enhanced tag, in terms of successful read rate, has been compared with that of some commercial Far Field and Near Field UHF tags. The experimental results are impressive and clearly demonstrate that ad hoc Far Field UHF tags are able to effectively solve many of the performance degradation problems affecting generalpurpose tags. Finally, the proposed tag has been also tested in extreme conditions, applying it directly on Tetra Pak packages containing liquid, with interesting results in terms of platformtolerant features.