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Here's an introduction to the tags, readers and software that make up an RFID system, as well as common materials handling applications of the technology.
Radio frequency identification, or RFID, is a form of automatic identification technology that-much like bar codes and magnetic stripes-can be used to carry data about an object and transfer it to a computer, reducing the time and labor needed for manual data entry.
While most automatic identification technologies require at least some labor (scanning, swiping, etc.), an RFID system can be truly automatic.
A basic RFID system includes an RFID tag, an RFID reader and a host computer. When a reader energizes a tag, the data stored in the tag's memory is transmitted to the reader via radio waves. The reader then communicates the necessary data to the host computer so the computer's software can act on the data. This entire process can be completed with no human intervention.
Common uses of RFID include card keys that control access to buildings, E-ZPass transponders that automatically pay roadway tolls and ID tags for pets and livestock. RFID technology also has many industrial uses, including several materials handling applications.
RFID tags
Most RFID tags have at least two parts:
A silicon chip for storing information
An antenna for receiving and transmitting a signal
Tags come in various shapes and sizes, depending on the application. The RFID tags typically used in shipping labels combine a tiny square chip (smaller than the head of a pin) with a 3- to 4-inch-wide antenna. Two of the most common antenna shapes for shipping labels are squiggle and double cross (see illustration).
RFID tags can be active, passive or semi-passive.
Active tags include a battery and use the power from the battery to transmit their signal. The battery gives this style of tag an especially long read range. It also increases the price of the tag.
Passive tags have no batteries and instead use energy from an RFID reader to power their transmissions. Passive tags are less expensive than active tags, but they have a limited read range.
Semi-passive tags, also called battery-assisted tags, use a battery to...