Radio Frequency IDentification (RFID), is a generic term for
technologies that use radio waves to automatically identify objects.
There are several methods of identification like: bar codes, optical
character readers or some biometric technologies, such as retinal
scans, but the most common is to store a serial number that
identifies the object, and perhaps other information, on a microchip
that is attached to an antenna. These technologies are used to
reduce the amount of time and labour needed to input data manually
and to improve data accuracy.
Advantages of RFID systems over barcodes:
It is not necessary to have a line of sight between the RFID tag
and the reader as there is with a barcode and scanner.
Information can be rewritten to the tag without having to see the
tag. This is true even if the tag is mixed into other items that
have been tagged.
Nearly 100% of RFID tags are readable, unlike items that contain a
printed barcode, which can become damaged with improper handling.
The potential problems associated with substandard print quality
of barcodes, which in turn leads to scanning and reading problems,
Other points to consider:
Barcodes are universally accepted because they are very
inexpensive and there are established standards for their use. RFID
technology is more expensive and has fewer universal standards in
the way they are used.
Even if RFID technology becomes as widespread as barcoding, it
will not totally replace the universally accepted barcode technology
Components of an RFID installation
Basically an RFID system is a communication between a reader and a
transponder (tag) at a defined frequency as other radio
An RFID system has basically four components: TAGS, READERS,
ANTENNAS and CONTROLLER.
A READER (also called interrogator) which can both read and write
information from or onto a tag.
The reader is the device that actually sends out the radio waves to
create a magnetic field. A passive RFID tag draws its power from
this magnetic field, which powers the circuits in the microchip
allowing it to transmit data back to the reader.
The CONTROLLER tells the reader, what, when, and for how long to
read tags. It collects and processes tag information in order to be
use in advanced systems.
The ANTENNA is a coil of copper wire wound design specifically to
emit RFID signals. The antenna allows the chip to transmit
information to a reader, which also has an antenna.
The TAG (or transponder) is a memory device, usually EEPROM,
programmed with a series of bits with built in antenna to receive
and transmit data. The basic types of RFID tags can be classified as
read/write and read only. The data stored on read/write tags can be
edited, added to, or completely rewritten, but only if the tag is
within the range of the reader. The data stored on a read only tag
can be read, but cannot be edited in any way. Read/write tags are
much more expensive than read only tags, so they are not used for
tracking most commodity items.
Tags can also be categorised as:
Active tags, which contain a battery that powers the microchip and
allows it to transmit a signal to the reader.
Semi-active (or semi-passive) tags, which contain a battery to run
the circuitry of the chip, but must draw power from the magnetic
field created by the reader in order to communicate with the reader.
Passive tags, which rely solely on the magnetic field created by
the radio waves sent out by the reader to create a current that can
be received by the antenna within the passive tag.