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
Login and post your comment!
Not a member?
Signup for an account now to access all of the features of RFIDJournal.com!