Will radio frequency identification work in the presence of metal, or will I run into problems?
Yes, you can, but you’ll need a special tag designed to work on metal. The issue with metal is that it detunes the tag’s antenna. This is similar to when you take a metal coat hanger and touch the antenna of an AM or FM radio. Suddenly, the station that was coming in so clearly is reduced to just static noise because the antenna is no longer tuned to the right frequency.
Similarly, if you place an ordinary passive HF or UHF transponder directly on metal, the metal will detune the antenna and it will not be able to receive the signal from the reader, and thus it will not be able to respond with its ID. On-metal tags have a thin layer of foam that keeps the metal antenna from touching the metal directly and becoming detuned. These tags sometimes work better than ordinary labels because energy can get in behind the antenna, through the foam, and the additional energy enables the tag to reflect back a strong signal that can be read further away.
I hope to see you at RFID Journal LIVE! 2020.
—Mark Roberti, Founder and Editor, RFID Journal
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