How Can Passive UHF RFID’s Read Range Be Improved When Tagging Liquids?

By RFID Journal

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Ask The ExpertsHow Can Passive UHF RFID’s Read Range Be Improved When Tagging Liquids?
RFID Journal Staff asked 8 years ago

Is there any way to make the range longer?

—Name withheld


There are a number of ways to attain a decent read range when tagging liquids. If you are tracking a case of bottled water, for instance, you could try putting the tag in an air gap. Usually, bottles are thinner toward the neck, creating space between the tag and the liquid. If there is no neck on the bottle, place the tag between the cylindrical containers, rather than at a point where a container meets the box in which it is packed.

If you are tracking individual items or liquid containers with no air gap, you could try using a special tag designed to work around liquids. R-pac International sells a tag designed for tracking wines and spirits (see R-pac Releases EPC UHF Label for Spirits, Wine, Cosmetics). The tag actually uses the liquid's properties to increase the read range. I've seen this tag be read from as much as 30 feet (9 meters) away.

Another (perhaps less elegant) solution is to put a thin sheet of metal between the tag and the liquid, and to use an on-metal tag. The metal sheet shields the tag from the effects of the liquid, and the on-metal tag takes advantage of waves bouncing off the metal to deliver a good read range.

—Mark Roberti, Founder and Editor, RFID Journal

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