EPix Offers Passive Long-Range UHF Tag for Wine, Spirits
The tag can be read from up to 36 feet away thanks to its near-field antenna, which uses a bottle's fluid contents and foil cork wrapper to boost its backscatter range.
Sep 25, 2013—
EPix, a U.K. company that manufactures electronic products and solutions, has developed a passive ultrahigh-frequency (UHF) tag for the wine and spirits industry that it claims has a 36-foot read range when applied to a full bottle of wine, as long as the bottle is standing upright. The tag, which ePix says would cost no more than a standard EPC Gen 2 UHF tag, employs a near-field loop antenna that couples with the metallic foil covering the top of a bottle, helping it achieve a longer read range than would otherwise be possible.
Liquids absorb the transmission of UHF RF signals, but ePix has patented a method for a passive RFID tag to use the electrical energy absorbed by the wine when that tag is placed against a bottle's exterior. The tag is attached to the side of the bottle, with one end situated beneath the metallic foil wrapping that a vintner typically places over a wine bottle's cork or cap. The foil wrapping, which couples with the tag, acts as an antenna. The remainder of the tag extends beyond the foil wrapper, where it makes capacitive contact with the liquid contained within the bottle.
"This tag is designed to increase the current flow in a near-field loop, enabling the tag to reflect a more powerful signal," says David Mapleston, ePix's technical director and founder.
Mapleston says he began developing the tag after speaking with one of his students at an Alien Technology Alien Academy RFID workshop, held in England. The student commented on the problem of counterfeit spirits sometimes sickening customers. Several spirit and wine companies do embed passive RFID tags in their bottles' labels for authentication, but those firms typically employ high-frequency (HF) 13.56 MHz tags to enable transmission in the presence of the fluids. Therefore, the tags are both expensive and require a very close read. By using UHF RFID technology, Mapleston explains, businesses could not only prove a bottled product's authenticity, but also track it through the supply chain or conduct inventory audits via a handheld reader.
However, Mapleston says, without a spacer or a resonant cavity (a recess with a radiating antenna) built onto it, a passive UHF tag has a limited read range. Such tags are more expensive than standard UHF tags, and measure 2 millimeters (0.08 inch) thick, making it impossible to discretely hide them on a bottle's packaging. What's more, he adds, they are not omnidirectional—that is, the tag transmits its backscatter signal in only one direction.
EPix tested several UHF tags on bottled wines to confirm this to be true, using the company's Power-Mapper product that tracks RF transmission, and found that when a bottle was tagged with a passive UHF tag lacking a spacer or resonant cavity, the tag's backscatter transmission dropped in power when located very close to the bottle.
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