Radio Frequency Identification (RFID): What is RFID?

(what it is and what its future may be)

An explanation of what RFID is

RFID is an automatic identification technology whereby digital data that is encoded in an RFID tag or "smart label" is captured by a reader using radio waves. RFID is similar to bar code technology but it uses radio waves to capture data from tags, rather than optically scanning the bar codes on a label. RFID does not require the tag or label to be seen to read its stored data which is a key factor of an RFID system.

RFID tags are integrated circuits

The tags consist of an integrated circuit (IC) attached to an antenna, usually a small coil of wires, plus some protective packaging; such as, a plastic card that is determined by the application requirements.

RFID tags can come in many forms and sizes. Some can be as small as a grain of rice. Data is stored in the integrated circuit and transmitted through the antenna to a reader. These tags are either "passive" (no battery) or "active" (self-powered by a battery).

Tags also can be read-only (stored data can be read but not changed), read/write (stored data can be altered or re-written); or a combination, in which some data is permanently stored while other memory is left accessible for later encoding and updates.

"Smart labels" are considered to be more sophisticated than "tags"

Smart labels are a particularly innovative form of RFID tag and operate in much the same way as a tag; however, a smart label consists of an adhesive label that is embedded with an ultra-thin RFID tag "inlay" (the tag integrated circuit plus printed antenna).

Smart RFID labels are more flexible because of the capabilities provided by silicon chips.

Smart labels combine the read range and unattended processing capability of RFID with the convenience and flexibility of on-demand label printing. Smart labels also can be pre-printed and pre-coded for use.

With on-demand applications, the tag inlay can be encoded with fixed or variable data and tested before the label is printed; while the smart label can contain all the bar codes, text, and graphics used in estblished applications.

Smart labels are called "smart" because of the flexible capabilities provided by the silicon chip embedded in the tag inlay. A read/write smart label also can be programmed and reprogrammed in use, following initial coding during the label production process.

An RFID reader is a radio frequency transmitter

An RFID reader is basically a radio frequency (RF) transmitter and receiver, controlled by a microprocessor or digital signal processor. The reader, using an attached antenna, captures data from tags then passes the data to a computer for processing.

As with tags, readers come in a wide range of sizes and offer different features. Readers can be affixed in a stationary position; for example, beside a conveyor belt in a factory or dock doors in a warehouse, portable (integrated into a mobile computer that also might be used for scanning bar codes), or even embedded in electronic equipment such as print-on-demand label printers.

Much more information about smart labels, smart cards, and many other definitions about radio frequency identification can be found at this RFID definitions listing.

How RFID Functions

Information is sent to and read from RFID tags by a reader using radio waves. In passive systems, which are the most common, an RFID reader transmits an energy field that "wakes up" the tag and provides the power for the tag to operate.

With active systems, a battery in the tag is used to boost the effective operating range of the tag and to offer additional features over passive tags; such as, temperature sensing. All of the data is collected from tags and then passed through familiar communication interfaces (cable or wireless) to host computer systems in the same manner that data scanned from bar code labels is captured and passed to computer systems for interpretation, storage, and action.

Some of the special features of RFID systems

  • RFID systems can provide error-free, wireless data transmissions, that are both battery-free and maintenance-free.
  • They do not require line-of-site scanners for operations.
  • The stored data can be altered during sorting or they can capture the workflow or process information.
  • RFID systems can usually work effectively even in harsh environments with excessive dirt, dust, moisture, and extremes of temperatures.
  • One of the components of RFID consists of tags that are electronically programmed with unique information.
  • Each paper-thin tag contains an etched antenna and a microchip with a capacity of at least 64 bits.
    • The word bit is a blend of binary and digit.
    • A bit is the smallest unit of information storable in a computer or a peripheral device, expressed as 0 or 1. Eight bits make a byte, the common measure of memory or storage capacity.
    • A byte is a set of adjacent bits, now commonly a group of eight, used in computing to represent a unit of data such as a number or letter; or a unit of computer memory equal to that needed to store a single character; therefore, 64 bits is the equivalent of "64 characters" (letters and/or numbers).
  • Tags are available in one of three types: read-only; write-once, read-many (WORM); and read-write.
  • Tags are read-only if the identification is encoded at the time of manufacture and not rewritable.
  • This type of tag contains nothing more than item identification.
  • It can be used for items acquired after the initial implementation of RFID.
  • The WORM tag's main advantage over a read-only tag is that information in addition to the identification number can be added; however, this information must be something that won't need to be changed.
  • An example would be a library that includes information about an author or item title if the tag has enough cpacity, but not a library location or circulation status.
  • Read-write tags, are chosen by most libraries and can have information changed or added.
  • For example, a library might add an identification code for each branch and that information could be changed if the holding location were subsequently changed to another branch of the library.
  • In library RFID, usually part of the read-write tag is secured againave placed RFID tags on staff and patron identification cards.
  • The tags cn be inserted in the items by a library, a book jobber, or the publisher when the book, etc. is completed.
  • Most libraries that have implemented RFID technology have done their own tagging.
  • Book jobbers that provide processing services are willing to insert RFID tags at additional cost, but publishers will not do it unless there are enough bookstores and libraries are willing to pay more for books with embedded tags.
  • Almost all libraries using RFID have tagged only library materials, but libraries can also tag small pieces of equipment. One academic library has dramatically reduced losses by protecting everything that is not fastened down.
  • A few libraries have placed RFID tags on staff and patron identification cards. Not only does that application identify patrons for charging and discharging of library materials, but also for access to restricted areas.

Generally, as far as RFID is concerned, we need to know more about this new technology which is spreading throughout the world and is playing such an important part in our lives, whether we know it or not and whether we like it or not.

List of Radio Frequency Identification or RFID articles.