RADIO FREQUENCY IDENTIFICATIONIntroductionRFID is a technology that detects and identifies objects using electromagnetic radio waves. This is handled by exchange of information between a reader and a tag attached to the object which includes data associated with the object. This can be used to detect and classify vehicles, animals, patients, shipped goods and airline baggage. [1]RFID technology involves two main components: transponders, also called tags or tags, contain the relevant information about the object and other interrogators, also called readers or transceivers, which extract the data from the tags. These tags can be passive or active tags. Passive tags use energy from the reader's EM radiation for processing, while active tags receive energy from an internal battery for processing and communication with the reader. An integrated electronic circuit is embedded in tags for storage and processing operations and an antenna that transmits and receives the RF signal. [2]Figure: RFID componentsSource: http://www.docstoc.com/docs/17328767/Draft-SP800-98The tags used in RFID have read-write operations, with a large storage capacity. The data can be modified a number of times. The tag and reader act as two-way radio communication in which each antenna carries modulation and demodulation of RF signals, with operating frequency ranges from low frequencies to UHF. Through the use of radio waves, RFID does not require line of sight for communication and the operating distance between the reader and the tag varies depending on the frequency range from a few centimeters to a few meters. [3][1] http://en.wikipedia.org/wiki/Radio-Frequency_identification[2] [3] http://www.docstoc.com/docs/17328767/Draft-SP800-98HistoryThe beginning of RFID took place in 1915, by the British with a system called IFF, which stands for Identification Friend or Foe. In 1940, during World War II, the first IFF transponder installation was installed in a German aircraft named FUG. [4] Léon Theremin invented a device in 1945 which retransmits an incident radio wave and audio information. This passive device activated from an external source became the precursor of RFID technology. [5]The concept of RFID originated in 1973 when Mario Cardullo invented a passive transponder that emits information when activated by an interrogation signal and consisted of a 16-bit memory unit for storage purposes. [6]In 1973, at Los Alamos National Laboratory, Steven Depp, Alfred Koelle and Robert Freyman developed the RFID tag system which uses 12-bit tags, operating at 915 MHz. [7]After many years of research, RFID tags were equipped with active tags that eliminated the use of an external power source..