Room-coverage improvements in UHF RFID with commodity hardware

Antonis G. Dimitriou, Aggelos Bletsas, John N. Sahalos

Research output: Contribution to journalArticlepeer-review


This 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 tagas 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.

Original languageEnglish
Pages (from-to)175-194
Number of pages20
JournalIEEE Antennas and Propagation Magazine
Issue number1
Publication statusPublished - Feb 2011


  • Electromagnetic measurements
  • Multipath channels
  • Radiofrequency identification
  • Ray tracing
  • RFID tags
  • UHF propagation


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