UHF Myths vs
. Reality?"> Given the relative newness of Gen 2, there are a lot of myths surrounding what UHF can and cant do, according to Impinjs Diorio. There are those who say HF works better for different materialswater or metaland those who say UHF will work just fine. "Many of you have heard the conventional wisdom that UHF doesnt work in liquids, that UHF tags dont fit [smaller items], that UHF doesnt work on metals, that you cant stack UHF," Diorio said during the RFID Journal Web seminar. "Conventional wisdom is wrong."The key concept to take away, according to Diorio, is that because near field attenuates rapidly, HF really only works in near field, while UHF works in both near and far field. "For a tag thats a foot away, it works great," Diorio said. "For a tag thats 10 feet away it works great." Diorio said Impinj tested UHF near-field tags in bottles of shampoo, lotion, even Gatoradenot on the bottle, but in the bottleand found the tags were readable. The company also found the tags werent susceptible to too much noise or to space considerations like being stacked, and they worked on metalafter a little tweaking. As for item size constraints, Avery Dennison developed small tags that work on vials of drugs, either on the top or bottom, which were also readable, according to Avery Dennisons Forster. "Gen 2 delivers performance upgrades," Forster said. "We can put UHF energy precisely where we need it, which gives us excellent control of when and where reads are and eliminates interference." Dutch researchers create RFID malware. Click here to read more. UHF can also impact tag costs, according to Diorio. "In UH every little coil of wire delivers a voltage and there needs to be a lot of coil to generate a voltage," Diorio said. "UHF is a single loopone turn, one layer. You dont have to worry about turn resistance, so tag costs with UHF will always be lower." UHF as a standard, however, has its detractors. ODINs benchmark study, released March 29, developed in conjunction with Unisys and pharmaceutical manufacturers, points to HF as the more appropriate technology for pharmaceutical tagging. "HF wins in this round in the battle of the frequencies by a technical knockout," said Patrick J. Sweeney Jr., president and CEO of ODIN. "We dont particularly care who wins these battles. What we care about is what works best for our clientsWal-Mart, Bristol-Myers Squibb, Colgate, Kraft." The reason ODIN undertook the study, according to Sweeney, is that he saw RFID adoption in the pharmaceutical industry stagnating, with people unable to decide whether they should invest in HF or UHF. HF may just win out. "This may be one instance where the Food & Drug Administration will actually trump Wal-Mart," said Sweeney, who noted that the FDA wants pharmaceutical companies to use RFID by 2007. "Wal-Mart is very desirous of a single infrastructure, which with UHF you get very close to. But the FDA still has many concerns around UHF. Theyre afraid [the energy from a reader] will do to vaccines and medicines what a microwave would do to a cup of coffee." Sweeney said he does believe that UHF holds great promise for the retail supply chain, particularly as the cost of near-field tags gets cheaper. "UHF is clearly where the [future of] large volume tags is going to be," Sweeney said. Check out eWEEK.coms for the latest news, reviews and analysis on mobile and wireless computing.
Diorio addressed the physics of UHF and of something defined as far-field (for example, 10 feet) and near-field (1 foot) tagging. UHF use in far-field tagging is relatively standard technology, whereas UHF in near-field tagging is emerging technology.