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Can Passive UHF RFID Get Any Better?

The technology has made great strides—and there are innovations on the horizon that will advance it even more.
By Mark Roberti
Aug 30, 2016

During the past five years, passive ultrahigh-frequency radio frequency identification systems have improved markedly. The read range has increased significantly due to development of more sensitive microchips and better antenna design. Security features have been added to prevent cloning and eavesdropping on tag-to-reader communication. And innovations have enabled tags to be read on metal products and even to be embedded in metal for tracking items such as medical devices. In fact, a recent report from the European EPC Competence Center, a Germany-based provider of RFID services, found that on-metal tags are becoming smaller and increasing in sensitivity and reliability (see EECC Benchmark Study Finds UHF Tag Performance Better Than Ever).

This raises two important questions. Do passive systems need further improvement and, if so, can they get any better?

The answer to the first question is certainly yes. Passive UHF RFID technology works well for many applications, but there are still some things end users would like it to do or do better. These things, if achieved, would dramatically boost adoption levels.

1. Capture tag data more consistently.
RFID systems are great for reading tags quickly. A single store associate can take inventory of 10,000 apparel items in two hours with a handheld RFID reader. It would take the same associate approximately 50 hours with a bar-code scanner, and the accuracy would not be as high.

Still, retailers would like to move to fixed RFID readers in stores and read all the tags on all the items on their shelves. Today's overhead readers are typically able to read only 50 percent to 90 percent of the tags. That's because tags on densely packed items often block the reader signal from reaching tags on other items behind or below them. Getting the read accuracy on overhead fixed readers up to 95 percent accuracy levels or higher would boost retail adoption.

2. Exclude extraneous reads.
In some cases, passive RFID readers are too good at capturing tag data. Often, a forklift truck reader will read tags on items on shelves, rather than just those on the forklift truck. And handheld readers sometimes capture tags on items on shelves the associate does not intend to inventory. Many end users say they would like to see the passive UHF read field be more defined or have readers use other methods to exclude tags they do not want to read.

3. Make the technology more plug-and-play.
At an RFID Journal event in 2003, Linda Dillman, then CIO of Walmart, showed a photo of the back of a smart shelf the retailer was trialing in one store—in the picture, a jumble of boxes with wires and cables was going in every direction. "This is not deployable in stores," Dillman said. The technology has improved since then. Readers come in neat little boxes and can have integrated or external antennas. Sleek portals often hide all the hardware.

But passive UHF systems frequently require some tweaking of power levels and careful positioning of reader antennas to optimize the read field. Most end users would like to be able to place a reader in a ceiling, doorway or wall and begin collecting data. We're not quite there yet.

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