Magazine Article | July 25, 2006

The Great Debate: HF Or UHF RFID

Source: Field Technologies Magazine

Item-level tracking (ILT) may be the next big initiative for RFID (radio frequency identification) technology, but you first have to consider your frequency options.

Integrated Solutions, August 2006

Every technology deployment follows the same general path: Identify the problem; evaluate possible technology solutions; choose the technology that best solves the problem.

When Wal-Mart and the DoD announced their RFID initiatives in mid-2003, however, the normally straightforward technology deployment path seemed to – at least temporarily – run astray. In the crush of attention that RFID initially received, many solution providers and end users started with the technology (RFID) before adequately identifying the problems and evaluating other potential technology solutions. Eventually, a state of normalcy returned. This brief recap may be instructive when it comes to the current debate over using HF (high frequency) or UHF (ultra high frequency) RFID tags for ILT applications.

In June, six supporters (ADT, Alien Technology, Impinj, Intel, Symbol, and Xterprise) of UHF RFID for ILT released a white paper entitled, “RFID and UHF: A Prescription for RFID Success in the Pharmaceutical Industry.” The 32-page document, which took a decidedly pro-UHF stance for ILT, addressed the recent advancements in UHF technology and some of its current perceived shortcomings. In doing so, the information contrasted with much of the current HF-based ILT thinking in the pharmaceutical industry.

We now arrive back at the technology deployment path. If the problem being solved is ILT, is HF or UHF the best solution? Or, is UHF being considered and promoted without properly identifying the problem to be solved? Your answers to those questions will likely depend upon your sources of information.

There is contention over the best frequency for ILT applications, but all solution providers seem to agree on at least one point: Choose the technology that best solves your problem. If end user enterprises follow this path, the right frequencies will be used for the right application. That may mean HF and UHF share significant portions of industry markets or that one frequency will be much more pervasive. “This is a meaningful debate [HF versus UHF for ILT] for the RFID industry, and it has to take place. Widespread adoption of RFID really can’t happen without this debate. We need to look at all of the data and results from pilots as part of an open dialogue,” says Bill Allen, director of strategic alliances, Texas Instruments RFid Systems. “Enterprise customers can then make informed decisions about which frequency works best for them. In the long term, the market will dictate the right frequency for item-level applications. And, that’s how it should work.”

Allen certainly isn’t alone in his thinking that, given accurate information, the market will actually drive appropriate solutions. However, “the market” needs to weigh a lot of information before making its collective decision. For instance, the FDA and several states are pressuring pharmaceutical companies to secure their products more effectively to cut down on counterfeiting and theft. And, RFID at the item level will play a key role in these initiatives. The UHF-centered white paper aimed to provide this market with information to aid in decision making. However, it’s not clear that advancements in UHF technology will proceed as quickly as the need to secure the pharmaceutical supply chain. Additionally, HF has already proven effective in several pharmaceutical projects for ILT. “HF has been tested and deployed for the past 8 to 10 years in applications ranging from libraries to hospitals. It’s stood up to harsh conditions. It’s very accurate. It’s a proven, stable technology,” states Ken Reich, director, marketing and public relations, TAGSYS. “If you need to deploy RFID at the item level and you need accuracy and consistency, then right now HF has to be the frequency of choice.”

The frequency debate for ILT is not so much about the present as it is the future. While solutions providers have used UHF for ILT demos and projects dating back four or five years, the level of discourse only became serious in early 2006 when Impinj announced its near-field UHF. The company demonstrated its technology at several industry trade shows by placing UHF tags in bottles of water and reading the tags from varying ranges. The display dispelled the myth that UHF tags could not be read through liquids. Additionally, the circular tags were smaller than a dime. The demonstration clearly signaled UHF as a potential solution for ILT apps. “It’s important to note that our expertise in UHF at the item level is only a little more than six months old. By the end of 2006, UHF will be recognized as the best choice for item level,” says William Colleran, president and CEO of Impinj. “UHF has tremendous economies of scale. We’ve proven that UHF works around liquids and metals. The tags are smaller and less expensive. And, there are not technical arguments around the UHF specifications.”

UHF for ILT also appears to have some serious backers outside of the vendor community. Wal-Mart and the DoD have both expressed their desires in the past to support a single frequency within their enterprises. And the inference is that frequency would be UHF. A single, do-it-all frequency for RFID tags is based on the near-field and far-field ranges of UHF technology. “It’s hard to imagine that UHF and HF could coexist within an enterprise supply chain,” says Andy Holman, senior business development manager at Avery Dennison. “The requirements to read tags vary so greatly as products move from manufacturing to retail locations and to consumers.” For example, DVDs could be tagged at the item-level with HF and at the case and pallet level with UHF. But, once the product reaches a retailer’s back room, HF makes less sense. Locating inventory in the back room requires far-field reads and a handheld UHF scanner. On the shelf, products could be tracked with both near and far field and using RFID at the POS could again use both near and far field. “Supply chains have such different requirements. It just makes sense that enterprises will prefer an RFID tag that has both near- and far-field capabilities as opposed to two separate tags and infrastructures. UHF is just more flexible and has more potential,” adds Holman.

The white paper issued in June aimed to address many of the technical challenges that were perceived to be shortcomings of UHF for ILT – mainly that UHF did not perform well around liquids or metals, UHF read ranges and interference could not be adequately controlled, and security features were lacking.  Assuming all of these technological barriers were sufficiently addressed and removed, UHF for ILT still faces a couple more hurdles. First, UHF is a highly regulated frequency in most parts of the world. While the United States has been accommodating for UHF RFID applications, the rest of the world has not exactly followed in lockstep. Most vendors agree that global regulation issues will be addressed through a combination of cooperation, technological workarounds, and retailer pressure. This is already happening, but will take some time.

The second issue that needs to be addressed is RF (radio frequency) absorption as it relates to biologicals. The possibility exists that the UHF frequency could actually raise the temperature level of medications and essentially alter their original states. The previously mentioned white paper addresses this issue by citing that no realistic tests have proven this to be true. “This is a topic that deserves further investigation, and that will be happening,” says Impinj’s Colleran. “We’re confident that UHF does not have a negative impact on medications. Tests will be conducted; the findings will be released to resolve this issue.” Other vendors concur that the effects of UHF are unknown, but all signs indicate that the impact will be neutral. Still, tests will have to be conducted to remove this barrier to adoption.

Plenty of analogies have been floated in the debate over HF and UHF for ILT applications. The VHS/Beta comparison is apt for supporters of UHF technology who see that frequency becoming pervasive. In short, the market will demand a single frequency supported by a single infrastructure. The big “winner” will be UHF. The other common view has the two frequencies peacefully coexisting with different frequencies used for different applications. Think of it as unleaded gasoline and diesel. Both fuels power vehicles, and both make sense depending upon their application. Presented with coherent, accurate facts, the market will likely determine the analogy that best carries the day. “It’s important to keep in mind that RFID is just a tool,” says Joe White, vice president, product management and tag engineering at Symbol. “Discussions within companies should not be about choosing a frequency as much as choosing the right tool for particular applications.”

So, we return to the technology deployment path. You start with the problem. You evaluate the potential solutions. You choose the technology that best meets your needs. It’s a simple formula that will keep enterprises on track and likely resolve the HF/UHF debate once and for all.