Room-coverage improvements in UHF RFID with commodity hardware Room-coverage improvements in UHF RFID with commodity hardware Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2015-10-262011enThis work studies the three-dimensional (3D) identification performance of UHF RFID systems with commodity hardware. Detailed three-dimensional propagation modeling is developed, with ray-tracing that allows examination of tag- as well as reader-antenna diversity. It is shown that multipath can enhance identification performance compared to free-space conditions. Furthermore, it is found that tag diversity can enhance identification performance on the order of 10%. Reader-antenna diversity becomes beneficial only when special attention is given to controlling the destructive summation of the transmitted fields and simple, general antenna-installation rules are provided. Performance can be further enhanced with the introduction of a phase shifter or appropriate transmission scheduling, and various examples are discussed. Measurements inside a room with a dense three-dimensional grid of passive RFID tags confirmed the results. Finally, a method to perform power-measurements with commodity RFID hardware that exploits the sensitivity-during-read threshold of each tag is put forth.http://creativecommons.org/licenses/by/4.0/IEEE Antennas and Propagation Magazine531175 - 194 Bletsas Aggelos Μπλετσας Αγγελος Sahalos, J.N. Dimitriou Antonis G. Institute of Electrical and Electronics Engineers