RFID Read on Metal

Emerson & Cuming Microwave Products has developed unique solutions to enable RFID tags to be read when placed on metal.  MetalTag is a small form factor, thin Gen 2 compliant, cost effective read on metal tag.
 

HF, UHF

Two popular frequencies used in passive RFID are 13.56 MHz (HF) and 860-960 MHz (UHF).  HF readers use magnetic field coupling to read the tag.  The tag is designed to resonate at 13.56 MHz so when in the presence of a magnetic field at 13.56 a voltage is established across the microchip which allows it to turn on and interact with the reader.  The chip will modulate the properties of the tag in a manner which can be detected by the reader.  Read range with HF systems are less than 1 meter.

The UHF band used in RFID spans from 860-960 MHz.  This range actually encompasses three separate bands which are used in the EU (865-868 MHz), the US (902-928 MHz) and Japan (952-956 MHz).  In a perfect world there would only be one frequency but various issues in the separate regions prevent this.  UHF readers transmit a free space electromagnetic wave.  The tag microchip must receive sufficient power from this wave to 'turn on'.  The tag will then modulate the backscatter (reflection) of the tag in a manner that can be read by the reader.  Read ranges of UHF systems can approach 30' or more.

RFID on metal

Both passive RFID types share the characteristic that the tags can not be read when they are placed on metal.  Tag read range will begin to deteriorate when the tag comes within a half inch or so of metal. A dielectric spacer made of a foam material is sometimes used to separate the tag from the metal.  This solution  is thick and bulky and has a tendency to be damaged when it extends so far from the object.  ECMP has developed the ECCOPAD^® line of RFID isolators which serve to enable RFID tags to read on metal objects with considerably less thickness than the traditional approach. 

Account Managers

Sales: Devin Sullivan

Technical Inquiries: Paul Dixon