RFID stands for Radio Frequency Identification. It is a method of identifying unique items using radio waves. It can be applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves .Typical RFID systems are made up of 2 major components: readers and tags. The reader, sometimes called the interrogator, sends and receives RF data to and from the tag via antennas. A reader may have multiple antennas that are responsible for sending and receiving the radio waves. The tag, or transponder, is made up of the microchip that stores the data, an antenna, and a carrier to which the chip and antenna are mounted.
There are many different versions of RFID that operate at different radio frequencies. The choice of frequency is dependent on the requirements of the application. Three primary frequency bands have been allocated for RFID use.
Low Frequency (125/134KHz) – Most commonly used for access control and asset tracking.
Mid-Frequency (13.56 MHz) – Used where medium data rate and read ranges are required.
Ultra High-Frequency (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) – offer the longest read ranges and high reading speeds.
RFID technologies cannot reliably cover areas wider than 4 to 5 feet, unsuitable for wide openings that are the norm in manufacturing, distribution and store receiving dock environments. Since UHF (Ultra High Frequency) can cover portals up to 9 feet wide it is gaining industry support as the choice bandwidth for inventory tracking applications including pallets and cases.
RFID tags are further broken down into two categories:
Active RFID Tags are battery powered. They broadcast a signal to the reader and can transmit over the greatest distances 100+ feet and are used to track high value goods like vehicles and large containers of goods. Shipboard containers are a good example of an active RFID tag application.
Passive RFID Tags do not contain a battery. Instead, they draw their power from the reader. The reader transmits a low power radio signal through its antenna to the tag, which in turn receives it through its own antenna to power the integrated circuit (chip). The tag will briefly converse with the reader for verification and the exchange of data. As a result, passive tags can transmit information over shorter distances (10 feet or less) than active tags. They have a smaller memory capacity and are considerably lower in cost making them ideal for tracking lower cost items.
There are two basic types of chips available on RFID tags, Read-Only and Read-Write. Read only chips are programmed with unique information stored on them during the manufacturing process. The information on read-only chips can never be changed. With Read-Write chips, the user can add information to the tag or write over existing information when the tag is within range of the reader. Read-Write chips are more expensive that Read Only chips. Another method used is something called a “WORM” chip (Write Once Read Many). It can be written once and then becomes “Read Only” afterwards.
Radio Frequency Identification (RFID) technology has been attracting considerable attention with the expectation of improved supply chain visibility for both suppliers and retailers.RFID is expected to provide huge advantages to manufacturers by offering the tools to better plan production and respond more quickly to market demand. It will facilitate automation of inventory counts and speed shipping and receiving at the distribution level.
