Essay on Rfid

1539 Words Nov 9th, 2012 7 Pages
Radio Frequency Identification (RFID)
RFID
RFID stands for Radio frequency identification.
It is a technology that uses communication via radio waves to exchange data between a reader and an electronic tag attached to an object, for the purpose of identification and tracking.
It's grouped under the broad category of automatic identification technologies.
RFID is fast, reliable, and does not require physical sight or contact between reader/scanner and the tagged item
RFID is also called dedicated short range communication (DSRC).
History
Invented in 1948 by Harry Stockman.
Initial application was during World War II-The United Kingdom used RFID devices to distinguish returning English airplanes from inbound German ones. RADAR
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* An antenna for receiving and transmitting the signal. * Varying levels of radio frequency give rise to different kinds of RFID tags: * Low frequency tags (between 125 to 134 KHz) * High frequency tags (13.56 MHz) * UHF tags (868 to 956 MHz) * Microwave tags (2.45 GHz)
An RFID enabled label needs to be selected according to the RFID frequency and protocol. The critical measure of the capability of an RFID label is its ability to be read from the necessary distance.
Types of RFID tags
There are three types of RFID tags: * passive RFID tags, which have no power source and require an external electromagnetic field to initiate a signal transmission, * active RFID tags, which contain a battery and can transmit signals once an external source ('Interrogator') has been successfully identified, * and battery assisted passive (BAP) RFID tags, which require an external source to wake up but have significant higher forward link capability providing greater range.
Passive RFID tags use the electrical current induced in the antenna by the incoming radio frequency scan. This means that the response of a passive RFID tag is brief.
Active RFID tags are used to track high-value goods that need scanning over long ranges.

RFID tag memory
Read-only tags * Tag ID is assigned at the factory during manufacturing * Can never be changed * No additional data can be assigned to the tag
Write once, read many (WORM)

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