RFID Frequencies Battle for Reception
Is RFID implementation being held up by the debate over HF versus UHF?
Tagsys has added a Gen 2 UHF tag, the Adaptive Kernel tag, to its mix.
The heat is on. The heat, that is, that could be generated by some radio-frequency waves. RFID World’s pharmaceutical track, “Item-Level Tracking in the Pharmaceutical Supply Chain,” which took place on February 28, gave attendees a snapshot of the debate currently taking place in the pharmaceutical industry. Mike Celantano, associate director, supply chain and RFID systems, for Purdue Pharma L.P., explained the firm’s application of ultrahigh-frequency (UHF) RFID tags to bottles of Oxycontin. Ken Reich, director, global marketing and public relations, Tagsys, described Pfizer’s use of high-frequency (HF) RFID tags for source tagging Viagra bottles, which Tagsys supplied. These successes, safely called such because they are currently being used in the supply chain, have left the rest of the industry debating their own uses.
Mike Rose, vice president of Johnson & Johnson Corporate, RFID/EPC Global Value Chain, raised this issue with FDA just weeks before at the agency’s Counterfeit Drug Task Force Public Workshop and Vendor Display. “What frequency will we use, and will it be compatible with the various packaging types?” he asked.
Dan Engels of MIT, whose predecessor, the Auto-ID Center, was the developers of the Electronic Product Code system, was also at the workshop. He summed it up this way: “[HF] 13.56 [MHz tags] read very well through liquids. [UHF] 915 [MHz tags] do not. It can still read through some of it, but I have got some issues there. We’re talking about laws of physics, unfortunately.”
Recent reports back up Engels. In March, Odin Technologies (Dulles, VA) a company offering RFID design deployment, testing, and installation software, released results of its HF-versus-UHF RFID evaluation, specifically in the pharmaceutical industry. HF was the winner.
“RFID will play a critical role in the pharmaceutical supply chain; the question burning in the minds of regulators, end-users, and supply chain participants is which frequency should we back?” says Patrick J. Sweeney II, Odin Technologies’ president and CEO. “The battle over frequency has slowed adoption—no one wants to invest when there is a risk of obsolescence.”
Unisys and Odin Technologies collaborated in the benchmarking research. Testing was based on hardware and tags currently available in production quantities. It focused on scientific evaluation of various tags and on several popular applications or use-case scenarios. Odin’s labs and Unisys worked with leading manufacturers, distributors, regulators, and agencies to determine what was most critical. Metrics included:
• Tag quality.
• Read distance.
• Orientation sensitivity.
• Material dependence.
• Maximum encode speed.
Odin found HF performance to be more effective from a materials standpoint, explains Christopher Fennig, director of professional services, Odin. “It doesn’t require line of site, and the impact of metals and liquids is far less significant for HF than for UHF,” he says. “Metal doesn’t detune HF like it does UHF.”
When it comes to encoding speed, Fennig admits that UHF is faster, “given the physics of communication—the frequency is 70 times faster,” he says. However, “we found HF to be fast enough and robust.” For instance, HF encodes at 15 tags per second, while UHF encodes at 30 tags per second. Fifteen tags per second far exceed printer thresholds and line speeds in Pharma.”
After completing scientific tag testing, Odin used standard pill bottles, liquid-filled bottles, and blister packs for use case testing:
• Item-level verification.
• Item-to-case aggregation.
• Pallet penetration.
Two themes were prevalent in study findings. “HF is material independent, performing the same with empty containers and with liquid-filled containers,” Fennig explains. Also, “HF responds the same when used with both empty and liquid-filled containers when speed changes.”
Odin tested three speeds for item-level verification: 15, 25, and 75 ft/min. UHF worked well with empty containers at all speeds. However, it performed poorly at 15 ft/min with fluids. HF worked well with empty and fluid-filled containers at 15 ft/min, but performance fell off at 25 and 75 ft/min.
Odin also looked at case packing. The firm tagged individual square bottles with all tags on the same face and then packed them 24 to a case in a single layer and 48 to a case in two layers of 24. The purpose was to identify the number of tags and their locations.
For UHF, every single tag was read for both the single- and double-layer cases at all speeds: 15, 25, and 75 ft/min. When filled with fluid, some of the bottles bearing UHF tags “were unreadable,” says Fennig, especially those on the bottom layer. “Speed didn’t drive this failure—the materials did,” he says.
HF read well at slow speeds, but when the speed increased, units were unread. “It failed at 25 ft/min,” he says. The results were identical with empty and fluid-filled containers.
Odin’s final evaluation involved reading case tags on pallets. Fennig points out that RFID tags can often shadow, or block reading, when RFID-tagged items are packed closely. “RFID can’t penetrate a conductive surface, so when tags are placed behind other tags, the shielded tags often can’t be read. However, “HF tags have less of an impact than UHF tags do,” he says. “But UHF case tags often prevent readers from capturing UHF item tags.”
For its own comparison, Magellan Technology also just released a white paper on RFID frequencies and protocols. According to the paper, “900 MHz is a frequency where the energy carried by the radio frequency radiation is attenuated by liquid. This attenuation not only causes a heating effect but, more important, the RFID energy absorbed by liquids can seriously reduce range.” In addition, “UHF is subject to severe environmental multipath propagation effects where reader signals can be reflected by environmental objects, particularly metal and high conductivity metals.” Magellan offers HF tags with phase jitter modulation (PJM) to speed data reading.
Endorsement of HF for item-level tagging isn’t new. In July 2004, Philips Semiconductors, Tagsys, and Texas Instruments produced the white paper, “Item-Level Visibility in the Pharmaceutical Supply Chain: A Comparison of HF and UHF RFID Technologies.”
The report says, “Due to a number of technical and deployment characteristics including read range, form factor, maturity, global standards, and worldwide availability, HF technology provides the most effective path with the lowest technical and business risk to achieving item-level identification and pedigree tracking for pharmaceutical and healthcare applications.”
UHF tag advocates, however, aren’t giving up. Celantano of Purdue Pharma, who implemented Class 0 UHF tags for tagging individual bottles, experienced very few failures despite some challenges to label application. Wal-Mart’s mandate is precisely what drove Purdue Pharma’s selection of UHF in early 2004, and the firm shipped bottles in November 2004. In 2005 Purdue Pharma embarked on an e-pedigree concept. “The fundamental building blocks for RFID-based serialized point-to-point pedigree exist today,” Celantano said.
Alan Melling, senior director of business development, RFID, for Symbol Technologies, which provided UHF tags to Purdue Pharma, says that all the reports about UHF not working with liquids and metals are misconceptions. “We have manufactured UHF tags for years that have been applied to metal products in other industries,” he explains. “Metal is metal. UHF can’t read through liquids or metals, but if the tag is designed appropriately, it can easily be applied to metal and read very reliably.” And, he says, “RFID tags don’t get hot during reading.”
Melling suggests custom-designed UHF tag antennas. “Build a tag for the application. Design a tag for Pharma, with the right read range and material requirements, and you will get good results.”
In addition to working with Purdue Pharma, Symbol is also actively involved in pharmaceutical pilots with its 1 × 1 in. tag, now in Gen 2 versions.
Tagsys launched its own Gen 2 UHF tag at RFID World, the AK tag (adaptive kernel tag), calling it “the package-is-the-tag” solution. “There are some interesting and very exciting developments unfolding, and the execution of an RFID strategy is not just about selecting a frequency,” explains Reich of Tagsys. “Technology and implementation are also imperatives.”
Reich admits that this is somewhat of a shift from Tagsys’ previous message, expressed in its 2004 report, but there are emerging technological advances surrounding UHF Gen 2 capabilities in terms of delivering reliable, accurate, and secure RFID infrastructure, he says. Reich adds that the UHF reading range is determined by a customized antenna. “We want to eliminate any frequency bias and instead focus on the application and specific customer need,” he says. Tagsys can print the Gen 2 UHF AK tag antenna directly onto a package using conductive inks, or it can incorporate copper or aluminum antenna elements into the package discretely. According to Reich, the AK tag is one of the smallest UHF tag in the 860–960 MHz range, with the antenna—or the kernel—sized at 12 × 8 mm.
Odin’s Sweeney, who was slated to participate in EPCglobal’s Healthcare Life Sciences Business Action Group in mid-April, has heard that UHF vendors are planning to produce a white paper in support of Wal-Mart’s mandate for UHF tags for item levels. “The most innovative UHF technology requires specific tags and antennas not yet in production,” says Sweeney, who swears he is frequency agnostic.
For instance, Impinj Inc. has developed a novel approach for making UHF work in pharmaceutical item tagging. Dimitri Desmons, vice president, RFID marketing, presented Impinj’s technology in the RFID World session, “UHF Solutions for Item-Level Tagging.” Applying Faraday’s Law of magnetic induction, Impinj has designed tags with antennas that operate in the near field, ranging from a few inches to four feet. Inlays have been manufactured by Avery Dennison and RSI ID Technologies. “Range is a function of antenna design,” said Desmons. “UHF Gen 2 using our technology works in proximity to metals, and in fact, metal could be used for part of the antenna,” he says. “Liquids, too, are no longer a problem.”
Could it end up being a battle between retailers and the government? “FDA is concerned UHF may have an effect on biologics because it generates heat. While Wal-Mart wants one standard infrastructure using UHF, FDA trumps Wal-Mart,” says Sweeney.
Regardless of what frequency prevails overall, it is important for drug companies to fully evaluate RFID options for their own products. Pharmaceutical companies will need to act soon, given FDA’s timeline. Patient safety and supply chain efficiency are at stake.