Radio frequency identification
From wikiMHEDA
Radio frequency identification (RFID) is a method of remotely storing and retrieving data using a small tag attached to or incorporated into a product. Its purpose is to enable data to be transmitted via a portable device (tag), read by a reader, and processed according to the needs of the particular application. RFID has the potential to become the most far-reaching wireless technology since the cell phone.
Transmitted data may provide information about product location, or specifics such as color, price, or purchase date. In some systems a return receipt can be generated. RFID tags contain far more detailed information than can be placed on a bar code. Some tags hold enough information to provide routing information for shipping containers, as well as a detailed inventory of what is inside the container.[1]
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History
Like so many advancements in technology, RFID was first developed and used during WWII. The concept for RFID came from radar experiments conducted during the war. After its invention in 1948, RFID underwent decades of further development and experimentation before it became popular in the commercial sector.
RFID first hit the market in the 1970s, although its use was limited due primarily to the restrictive cost of tags. After another decade of progress and development the first commercial toll collection system was implemented in Norway in 1987. This launched an aggressive campaign for the use of RFID in toll systems, and by the early 1990s, toll collection systems had spread across the United States. The popularity of these automated systems led to further funding and development for RFID systems.
During the 1990’s the proliferation of competing systems and radio frequencies employed created the need for standards and interoperability. Most warehousing operations can use large readers which use low radio frequencies. Other industries use higher frequencies. As complexities and uses increased, standards were developed to allow systems to work together. These standards continue to be updated as the technology expands and grows.
The latest development in RFID systems came with the miniaturization of RFID tags, which improved the use of the systems in manufacturing. The price of the tags also dropped significantly, to a point where they could be more readily available for wide-spread use.[2]
RFID Tags
- Main article: RFID tag
An RFID tag is a microchip combined with an antenna in a compact package. The packaging is structured to allow the RFID tag to be attached to an object to be tracked. The tag's antenna picks up signals from an RFID reader or scanner and then returns the signal, usually with some additional data. RFID tags can be very small - the size of a large rice grain. Others may be the size of a small paperback book.[4]
Active RFID Tags
Active RFID tags are equipped with a battery that can be used as a partial or complete source of power for the tag's circuitry and antenna. Some active tags contain replaceable batteries for years of use; others are sealed units. (Note that It is also possible to connect the tag to an external power source.)[5]
Passive RFID Tags
Passive RFID tags do not contain a battery, the power is supplied by the reader. When radio waves from the reader are encountered by a passive RFID tag, the coiled antenna within the tag forms a magnetic field. The tag draws power from it, energizing the circuits in the tag. The tag then sends the information encoded in the tag's memory.[6]
Advantages of RFID
- Detail - RFID tags can contain far more detailed information than bar codes.
- Line of sight - Bar codes require a clear line of sight between the scanner and the bar code, a need that is absent from the RFID.
- Volume - It is only possible to scan one bar code at a time. Within the field of a reader, hundreds of RFID tags could be read within seconds.
- Variety - RFID codes are long enough that every RFID tag may have a unique code, allowing an individual item to be tracked as it changes location. Bar codes are limited to a single code for all stages of movement of a particular product.[1]
- Inventory efficiency - Because line of sight is not required to read RFID tags, inventory can be performed in a highly efficient method.
- Return on investment - Though the cost may be high at first, the total cost of ownership should go down over the years and provide a return on investment, if the implementation provides a significant method to improve business processes.[7]
Disadvantages
- Dead areas and orientation problems - Certain areas may have weaker signals or interference. Poor read rates are sometimes a problem when the tag is rotated into an orientation that does not align well with the reader. These issues can usually be minimized by properly implementing multiple readers and using tags with multiple axis antennas.
- Security concerns - Because RFID is not a line of sight technology like bar coding, new security problems could develop such as data theft and fraud.
- Ghost tags - In rare cases, if multiple tags are read at the same time the reader may read a tag that does not exist. Therefore, some type of read verification, such as a CRC, should be implemented in either the tag, the reader or the data read from the tag.
- Proximity issues - Tags cannot be read well when placed on metal or liquid objects or when these objects are between the reader and the tag.
- High cost - Because this technology is new, the components and tags are expensive compared to bar codes. In addition, software and support personnel that are needed to install and operate the RFID reading systems may be costly.
- Unread tags - When reading multiple tags at the same time, it is possible that some tags will not be read and there is no sure method of determining this when the objects are not in sight.
- Vulnerable to damage - Water, static discharge or high power magnetic surges (such as from a close lightning strike) may damage the tags.[7]
Controversy Over RFID Use
RFID has raised the issue of privacy amonst a number of concerned advocates. Consumers' privacy may be being invaded if they are unaware of an RFID tracking tag on a product, or if a tag is unable to be removed. These concerns typically apply to the use of RFID in retail and consumer goods. Concerns have also arisen over the security of the information on an RFID tag, and whether the information can be stolen from a scanner operating at a distance. Opposition to RFID is minimal, however, and proponents of the technology are confident it will diminish altogether as the use of RFID becomes more commonplace across a variety of industries.[1]
References
- http://www.referenceforbusiness.com/management/A-Bud/Bar-Coding-and-Radio-Frequency-Identification.html
- http://www.slais.ubc.ca/COURSES/libr500/04-05-wt2/www/T_Gnissios/history.htm
- http://www.rfidjournal.com/article/articleview/1338/1/129/
- http://www.technovelgy.com/ct/Technology-Article.asp?ArtNum=50
- http://www.technovelgy.com/ct/Technology-Article.asp?ArtNum=21
- http://www.technovelgy.com/ct/Technology-Article.asp?ArtNum=47
- http://www.idautomation.com/rfid_faq.html
