European EPC Competence Center Updates UHF Tag Study

The tests were performed on tags from Alien Technology, Avery Dennison, KSW Microtec, Omron, RSI ID Technologies and UPM Raflatac. All inlays conformed to the EPC Gen 2 and/or ISO 18000-6C standards, and all were tested separately at the frequencies allowed for use in Asia, Europe and North America (ranging from 800 to 1,000 MHz).

This year, the EECC bolstered the study with new techniques designed to provide more comprehensive tag performance data. After tests were conducted on the free air, Teflon, bottle and metal reflector, researchers measured an additional eight reference materials that characterized the physical (dielectric) parameters of all possible substrates without water and metal. The researchers then employed computer modeling to predict tag performance on additional materials derived from the tested substrates.

"With all [the EECC] reports before, you did not get an answer on special applications," von Bonin says. "But our goal is to give the user an answer for every application—on all substrates, at all frequencies, from all directions." Although the performance of all tags improved overall, von Bonin says the tests revealed dramatic differences among the various ICs. In fact, he adds, each tag performed differently, depending on the frequency.

"That's why a lot of tags are optimized for the U.S. or Europe frequencies, but also are optimized for different subsurfaces," von Bonin says. "But that's not the answer the user needs. He doesn't want to have a different tag for each different application in the same company. And it's much more complicated—if you have one tag on two different materials, with different dielectric parameters, than you [can have] different read ranges at the same frequency because of detuning effects."

That, according to von Bonin, is why studies such as that conducted by the EECC are necessary. "There is no general answer," he states. "[The] read range of one tag is always dependent on frequency and subsurface." The updated report is available from the EECC for €795 ($1,255), or for €395 ($625) as part of a five-year subscription.