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Focus: RFID and Automated Identification and Data Collection (AIDC)

Feature Article from Our RFID and AIDC Subject Area - See All

From SCDigest's OnTarget e-Magazine

- Feb. 18, 2014 -


RFID and Auto ID News: New Technology from Cambridge Said to Greatly Improve RFID Read Range, Accuracy - but May not Do Much for the Supply Chain


Use of Distributed Antenna System Extends Read Range for Passive Tags to 20 Meters, Eliminates Dead Spots


SCDigest Editorial Staff

Researchers at the University of Cambridge in the UK have invented a new approach that they claim will provide breakthrough improvements in reading of passive RFID tags. But even if the claims are proven correct, it's not yet clear what the supply chain applications will be.

SCDigest Says:


The technology does seem to hold potential for real-time locator systems in a distribution center or manufacturing operation where, for example, pallets could receive passive tags and be tracked for location and movement.

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The new system improves the accuracy of passive (battery-less) RFID tag detection from roughly 50% to near 100% in some scenarios, and increases the reliable detection range from two to three meters to approximately 20 meters - a breakthrough advance.

The technology and its advantages were recently unveiled in an article in the journal IEEE Transactions on Antennas and Propagation.

The focus on the research seems to be on reading relatively static tagged objects in some area or building. Much of the research, for example, was focused on reading tagged documents, as might be found in legal or medical offices.

The system would enable users to know in real time in which room (or even in which part of a very large room) a file may be located. Currently, such systems generally depend on users to scan documents as they are putaway or moved, or require a series of readers at key storage points.

Whether these exciting new capabilities can extend to the supply chain, however, is unclear at best.

New Approach to Antenna Placement

The heart of the technology is something called a distributed antenna system (DAS), a technique commonly used to improve wireless system performance in a building, but apparently not until now used to enhance RFID.

By knowledgably placing a series of four bistatic antennas cable-connected to a reader, read range can be improved by some ten-fold, and read rates are dramatically reduced to almost the point of zero by eliminating dead spots, the Cambridge researcher say. Each set of antennas includes one dedicated for transmitting the RF signals and another for receiving them.

The result is what they call a "wide area" reader network, in which a single reader is capable of covering some 400 square meters of territory, a dramatic increase from current capabilities.

They add that while several other methods of improving passive RFID coverage have been developed, they have not addressed the issues of dead spots, which are caused by wireless signal reflection that in effect cancels two signals out.

(RFID and AIDC Story Continued Below)




When headline news of the new technology first broke, SCDigest was hoping that perhaps the technique could be used for some vexing supply chain related applications, such as "x-raying" all the tagged cartons on a pallet, or accurately scanning all the items in a grocery cart as it moves through the point of sale area.

Alas, such applications on not on the Cambridge researchers radar.

"We didn't look at those kinds of use cases," said the university's Dr. Sithamparanathan Sabesan n an email to SCDigest, adding that he "would not be optimistic" the technology would work in those applications.

But the technology does seem to hold potential for real-time locator systems in a distribution center or manufacturing operation where, for example, pallets could receive passive tags and be tracked for location and movement. Such RTLS systems today often use much more expensive, battery-powered tags, and/or require a large number of readers to cover a building.

Perhaps this DAS-based technique could lower the costs for deploying a RTLS versus current approaches.

Sabesan has started a new company to commercialize the technology. It is called PervasID, and will be focused on the document tracking applications for now. In addition to the basic reading capability, the company has application software that for example sends off an alert if desired if a document is moved to a different room or other changes to its status.

Do you see any supply chain applications for this new wide-area passive tag reading technology? Let us know your thoughts at the Feedback section below.

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