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radio ID tags

See RFID tag.

RFID tag

An electronic identification device that is made up of a chip and antenna. For reusable applications, it is typically embedded in a plastic housing, and for tracking shipments, it is usually part of a "smart" packaging label.

Reusable Hard Tags
For RFID applications such as toll collection and vehicle and container tracking, the tags are used over and over for many years. Such tags are built into a plastic housing like handheld calculators and other electronic devices.

Toll Collection
This toll collection tag is an example of a reusable, "semi-passive" RFID tag. Because radio frequencies (RF) penetrate glass and plastic, the chip and antenna can be built into a rigid housing that is mounted inside the car.

Inside the Hard Tag
The largest components inside this tag are the battery (bottom right) and antenna (top middle). Also called "semi-active" tags, they augment the energy coming from the reader and do not continuously beam signals as do "active" tags.

Smart Labels
A smart label contains the RFID tag as well as printed barcodes and alphanumeric characters. The printed material can provide redundant UPC and EPC data that can be picked up by a barcode scanner or read by a warehouse employee if the RFID tag cannot be read. RFID smart labels are printed and encoded at the same time in an RFID printer.

The RFID portion of the smart label is called an "inlay" and is adhered to the back of the paper label, very often by a different manufacturer. See RFID inlay and RFID.

A Smart Label Printer
Note the copper RFID antenna on the back side of this smart label. The RFID inlays are adhered to the back of the label stock, which is sent to the customer for printing and encoding. (Image courtesy of Intermec Technologies,

The Squiggle Tag
Alien Technology was one of the first companies to make RFID tags, and its various Squiggle designs became widely used. (Image courtesy of Printronix, Inc.,

It's About Antennas
The patterns in these Avery Dennison RFID inlays are the aluminum and copper antennas. The black dot is the chip. Primarily used for passive, smart labels on cartons and pallets shipped from suppliers, the various designs fulfill different applications. For example, metal cans and liquids in a carton "detune" the tags and impede backscattering. (Images courtesy of Avery Dennison Corporation,

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