Aug 14, 2008This article was originally published by RFID Update.
August 14, 2008—RFID solutions provider Simply RFiD posted an entry on its blog a few weeks ago entitled RFID Read Range: Just how far can RFID track something?. In it, Simply RFiD president Carl Brown reported the read ranges on Gen2 technology that his engineers have found consistently in recent months. Those ranges were long enough to prompt skepticism from some readers -- and to prompt RFID Update to interview Brown for more explanation. The result was a decidedly bullish view of where Gen2 technology performance stands today, and where it is going in the near term.
"In the last year or two, RFID performance has definitely gotten a lot better. It used to be 10 feet [read range] was the goal, and you'd be happy to get 12," Brown told RFID Update referring specifically to Gen2. "Now we're seeing 20 feet without any issues at all. You can even have the tag in strange orientations, and you're still going to get the read."
Brown elaborated on his blog post, which grouped deployment environments into four buckets: difficult, average maximum, free space, and optimized. "Difficult" refers to challenging setups like those with proximity to metal or liquid. In such environments Brown's team reliably gets 10-foot reads. "Average max" refers to most configurations, in which there is no unusual impediment. Here Simply RFiD reports 40 feet. "We can plan to have an effective working range of 40 feet and be confident we will achieve 100 percent reads," Brown writes in his blog post. "Free space" refers to an open-air configuration with some optimization to ensure that the tags are directly facing the readers for clear line-of-site. Here they get 60 feet, but Brown acknowledges that such a setup is unlikely. Lastly, in an "optimized" environment Simply RFiD can achieve read ranges as high as 120 feet. "To create an optimized environment, we need a clear view of the tag, metal reflectors to help signal bounce and a low-noise environment. Rarely can we make an optimized situation in a deployment -- but, when we need to, we can." As rare as the optimized scenario might be, it does illustrate the potential of Gen2 technology.
"So, more to the point, how far can we track you or an item you are carrying with RFID?" Brown writes. "Typically, about 40 feet. And, absolutely within 20 feet."
One caveat to these impressive numbers is that they depend on Simply RFiD's chosen hardware combination, which is currently Avery Dennison AD-224 inlays paired with ThingMagic's M5 reader. It is this particular setup that has yielded the longest read ranges for the company. But Brown acknowledged that they have not tested all Gen2 readers and inlays on the market, so theirs should not be considered the definitive best combination.
Furthermore, the technology is developing so fast that such optimized reader-tag pairings are very much a moving target. Product iterations on both the reader side and the inlay and RFID tag chip side are common, any of which can see one product leapfrog the others in its category. Watch for new versions of Gen2 silicon chip technology from the three leading providers Impinj, Alien, and NXP. The Gen2 tag chip is probably the most important component of a system. After that watch for major new versions of readers, which can also exhibit huge performance gains. Brown points to the difference between ThingMagic's M4 and M5. While the M4 was a very strong reader, the M5 is in a whole different league, he says. After readers and tag chips, other components of an RFID system include the tag inlays and the reader antennas, also products that are seeing constant innovation and improvement. "[Avery Dennison's] AD-222 is great and is a great workhouse but AD-224 is the next generation and it's better.
"This technology is moving fast. Antenna, readers, cables, tags are all changing every six months," concludes Brown. "The most important aspect: just do it. It works."
