How Do RFID Tags Designed for Metal Surfaces Function?

By RFID Journal

  • TAGS

Can such tags be thin?

—Name withheld

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RFID transponders designed to work on or near metal usually have a spacer cushion preventing a tag from being detuned. When you touch a metal hanger to the antenna of a transistor radio, the antenna is detuned and you hear a lot of noise instead of a clear broadcast. Similarly, an RFID transponder's antenna becomes detuned and cannot receive energy from a reader. The cushion prevents such detuning from taking place. Tags might have a specially designed antenna as well, to help improve read range.

At present, I am unaware of any thin tag that can lay flat on metal. However, that could change within a few years. Researchers at North Dakota State University's Center for Nanoscale Science and Engineering (CNSE) have developed an antennaless RFID tag that essentially transforms a metal object into a device's antenna (see The Object Is the Antenna). The chip and a small loop would lay flat on the metal. Such an innovation, however, is still in the research and development phase.

—Mark Roberti, Founder and Editor, RFID Journal