A group of researchers at the Univ. of Cambridge have published a study in the IEEE journal Transactions on Antennas and Propagation which describes how a novel antenna system used with standard RFID tags is able to eliminate coverage dead spots.

 

In a trial using RFID tags distributed in a 20 x 15 m office environment they showed a standard tag reader system reached just 50 % detection rate while their distributed antenna system (DAS) improved the success rate to near 100 %. Dr. Sithamparanathan Sabesan and Dr. Michael Crisp, along with Professors Richard Penty and Ian White achieved an increase in RFID range and accuracy by multicasting the RFID signals using four transmitting and receiving antenna pairs, which allowed them to dynamically move communication dead spots thereby effectively producing an error-free system.

 

 “Conventional passive UHF RFID systems typically offer a lower useful read range than this new solution, as well as lower detection reliability,” said Dr. Sithamparanathan Sabesan of the Centre for Photonic Systems at the Department of Engineering. “Tag detection accuracy usually degrades at a distance of about two to three meters, and interrogating signals can be cancelled due to reflections, leading to dead spots within the radio environment.”

 

The team is currently working to add location functionality to the RFID DAS system which would allow users to see not only in which zone a tagged item is located, but also approximately where it is within that space. The system was awarded the 2011 UK RAEng/ERA Innovation Prize and is being commercialized by the Cambridge team.