Passive UWB RTLS System Passes Key Test

By Admin

Tagent successfully tested its first passive ultra-wideband real time location system (RTLS) chip and said it expects to release the technology late this summer. Tagent's system uses peripheral power nodes to eliminate the need for a battery on the chip and to increase the coverage of reader networks.

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This article was originally published by RFID Update.

February 2, 2009—After more than four years of development, Tagent has produced its first working prototypes of passive ultra-wideband (UWB) real time location system (RTLS) tags. The company plans to begin producing the tags plus associated readers and peripherals late this summer.

"We recently got our first silicon back and it worked almost perfectly. We're making some adjustments and will probably have to do one more fab," Tagent vice president of marketing and business development Geoff Zawolkow told RFID Update. "We now know our technology works."

Tagent's Talon tags and associated technology differ from other UWB RTLS systems on the market in several significant ways:

  • No batteries are used to power the tag and enable transmission to the reader.
  • Tags receive energy to communicate from power nodes that are separate from the reader.
  • The tag chip and antenna are integrated on a single integrated circuit.
  • Tags measure 2 by 2 by 0.1 mm, which is significantly smaller than other UWB tags.

"The biggest thing is that we're able to put the antenna together with the chip. It took us about four and a half years to solve that challenge," said Zawolkow. "Integrating the chip and antenna eliminates points of failure, doesn't require another step in the production process, and allows us to create very small tags."

The battery-free design also enables compact tags. Each power node transmits a UWB signal that covers approximately a 1-meter radius. Tags within the radius harvest energy from the signal and communicate to the reader, which has a range of about 10 meters. The system provides location accuracy to within 250 mm. Each tag has 128 bits of factory-programmable, read-only memory.

Tagent expects the tags to cost about 50¢, which is significantly less than current RTLS tags. The power nodes, which are not part of traditional RTLS systems, cost about $50. Tagent's architecture has one more layer than traditional RTLS systems -- the power nodes -- but uses a network of low-cost power nodes to cover a zone and report to a single reader, instead of using a network of readers to provide coverage. The architecture is similar to what Mojix introduced last year for its extremely long-range passive UHF system (see Startup Touts 600-foot Read Range for Passive RFID).

"We can place several very inexpensive power nodes around an area to be read and have a single relatively expensive reader read the data from the tags," Zawolkow said. "We do use the location of the power nodes as a key location tool. You cannot do that with a [passive RFID] system because there is no low-cost power node.

The Tagent system can be deployed to provide full coverage, or to monitor chokepoints or key areas, such as doorways or storage cabinets.

"You can think of us being able to do anything a traditional UWB RTLS system can do, but we can also track small objects," Zawolkow said. "We're very interested in blood sample tracking at commercial laboratories. You can't track sample tubes with RTLS tags now because you can't have a big antenna hanging off the tube. Batteries also make tags too big and too expensive to put tags on tubes. Our tags are very small and flexible, which means they can be put into labels, woven into cloth or integrated into a variety of packaging."

Tagent plans to focus on the core UWB RTLS markets of healthcare and manufacturing. However the company thinks it can automate new processes within those verticals because of the small size of its tags. Tagent has three pilot projects scheduled starting this spring, but the customers, industries and applications are being kept confidential.

"We envision coexisting with traditional UWB RTLS systems. You can read current tags and our tags with a single reader, and we envision that happening. Hospitals might use a traditional UWB system to track their infusion pumps or other equipment, and our technology to track samples that are drawn from patients, or even patients and staff themselves."

Tagent formed in 2004 to develop this technology and has no other commercial products. It has received four patents in the past year and has four others pending. The company is currently developing sales channels and seeking partners.