Sep 25, 2013EPix, 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.
When the bottle is on its side, however, its liquid contents may no longer be in capacitive contact with the tag's antenna. What's more, the wine flows to the top of the bottle in such a scenario, and can thereby interfere with the electric field in the foil wrapping, resulting in a read range closer to about 9 feet.
"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.
On the other hand, Mapleston found, during his research into a solution, that near-field antennas operated even when underwater. The near field—the magnetic part of the electromagnetic wave—can pass through fluids instead of being absorbed by them.
Therefore, Mapleston's team worked with an Alien near-field passive UHF tag that can be coupled with a bottle's metallic foil covering, in order to provide a longer tag transmission range. By using the RF signal's electrical field absorbed by wine, the tag can boost the power of the backscatter signal that it sends back to an interrogator, to a range of 11 meters (36 feet). He found that the tag also transmitted omni-directionally, so that with four reader antennas—each deployed along a different wall within a 60-square-foot room—he was able to capture a bottle's tag anywhere within that room.
According to Mapleston, the technology works when numerous bottles are packed together as well. "Pointing a reader at 200 bottles in crates will work well," he states, "as long as you set the reader antennas to the correct position"—around a room, for example. In that way, he predicts, the tags can be read as effectively as any UHF tag in such reading environments as warehouses or bottling plants. "High-speed conveyer belts and dock-door loading will be within normal UHF RFID performance criteria."
By providing UHF tags with a long read range for bottled spirits and wines, Mapleston says, the company now hopes to allow wine companies and other customers to track their goods throughout the supply chain. For example, a forklift could carry a stack of cases filled with wine through a reader portal, and the reader should capture every bottle's tag ID number. In that way, the user could gain updates regarding the location of each bottle of wine as it moves from the point of manufacture to the store. Individuals with handheld readers could then capture inventory updates indicating which bottles were on the shelves, or packed in cases, and a shelf reader could also make it possible for stores to track which bottles are most often picked up from the shelf—an indication of which are drawing the most interest from customers.
To date, ePix has only tested the tags within its own laboratory setting. However, the company now hopes to secure pilots with wine manufacturers, distributors or retailers.
The new ePix capsule tag measures approximately 11 millimeters by 15 millimeters (0.4 inch by 0.6 inch) and is made with an Alien Higgs 3 UHF chip. Its long range, Mapleston notes, can best be achieved when placed at the bottom of the foil wrap, with the chip positioned between the wrap and the wine. The rest of the tag would then be covered with a piece of paper or a plastic sleeve, thereby making it discreet enough that consumers would not notice its presence. Initially, the firm is providing small quantities of the tags for pilots, for as little as 12 cents apiece, depending on volume.
Solutions based on the ePix range of tags are now being marketed by Interactive Product Solutions (IPS). The system consists of ePix tags, standard EPC Gen 2 RFID readers, antennas and software. Discussions are currently underway with several potential end users, according to Brian Weeks, IPS' director. IPS is also assisting ePix in identifying and supporting other systems integrators interested in purchasing ePix tags, Weeks says.
