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Rfd Letter to Radio Farm Directors From Radio and.


Uploaded by associate-adrianna-flores on May 30, 2014

Radio-frequency identification ( RFID ) uses electromagnetic fields to automatically identify and track tags attached to objects. The tags contain electronically stored information. Passive tags collect energy from a nearby RFID reader's interrogating radio waves . Active tags have a local power source (such as a battery) and may operate hundreds of meters from the RFID reader. Unlike a barcode , the tag need not be within the line of sight of the reader, so it may be embedded in the tracked object. RFID is one method for Automatic Identification and Data Capture (AIDC). [1]

RFID tags are used in many industries, for example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line; RFID-tagged pharmaceuticals can be tracked through warehouses; and implanting RFID microchips in livestock and pets allows for positive identification of animals.

In 2014, the world RFID market was worth US$8.89 billion, up from US$7.77 billion in 2013 and US$6.96 billion in 2012. This figure includes tags, readers, and software/services for RFID cards, labels, fobs, and all other form factors. The market value is expected to rise to US$18.68 billion by 2026. [3]

In 1945, Léon Theremin invented a listening device for the Soviet Union which retransmitted incident radio waves with the added audio information. Sound waves vibrated a diaphragm which slightly altered the shape of the resonator , which modulated the reflected radio frequency. Even though this device was a covert listening device , rather than an identification tag, it is considered to be a predecessor of RFID because it was passive, being energized and activated by waves from an outside source. [4]

Similar technology, such as the IFF transponder , was routinely used by the allies and Germany in World War II to identify aircraft as friend or foe. Transponders are still used by most powered aircraft. Another early work exploring RFID is the landmark 1948 paper by Harry Stockman, [5] who predicted that "... considerable research and development work has to be done before the remaining basic problems in reflected-power communication are solved, and before the field of useful applications is explored."

An early demonstration of reflected power (modulated backscatter) RFID tags, both passive and semi-passive, was performed by Steven Depp, Alfred Koelle, and Robert Frayman at the Los Alamos National Laboratory in 1973. [8] The portable system operated at 915 MHz and used 12-bit tags. This technique is used by the majority of today's UHFID and microwave RFID tags. [9]

Uploaded by associate-adrianna-flores on May 30, 2014


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