RFID Basics: Radio Frequency
Identification Information
RFID Systems
information provided by the Wikipedia, the free encyclopedia
The History of RFID (Top)
Although
some people think that the first known device may have been invented
by Leon Theremin as an espionage tool for the Russian Government in
1945, the first real usage of RFID devices predates that. During
World War II the United Kingdom used RFID devices to distinguish
returning British airplanes from inbound German ones. At first,
RADAR was only able to signal the presence of a plane, not the kind
of plane it was. Later, Identification friend or foe (IFF)
transponders carried in friendly aircraft gave them a distinctive
"blip" on radar screens.
Perhaps
the first work exploring RFID is the landmark 1948 paper by Harry
Stockman, entitled "Communication by Means of Reflected Power"
(Proceedings of the IRE, pp1196-1204, October 1948). Stockman
predicted that "...considerable research and development work has to
be done before the remaining basic problems in reflected-power
communication are solved, and before the field of useful
applications is explored." It required thirty years of advances in
many different fields before RFID became a reality.
Types of RFID tags (Top)
RFID tags
can be either active or passive.
Passive
RFID tags do not have their own power supply: the minute electrical
current induced in the antenna by the incoming radio-frequency scan
provides enough power for the tag to send a response. Due to power
and cost concerns, the response of a passive RFID tag is necessarily
brief: typically just an ID number (GUID). Lack of its own power
supply makes the device quite small: commercially available products
exist that can be embedded under the skin. As of 2004, the smallest
such devices commercially available measured 0.4 mm × 0.4 mm, and
thinner than a sheet of paper; such devices are practically
invisible. Passive tags have practical read ranges that vary from
about 10 mm up to about 5 metres.
Active
RFID tags, on the other hand, must have a power source, and may have
longer ranges and larger memories than passive tags, as well as the
ability to store additional information sent by the transceiver. At
present, the smallest active tags are about the size of a coin. Many
active tags have practical ranges of tens of metres, and a battery
life of up to several years.
As
passive tags are much cheaper to manufacture and do not depend on a
battery, the vast majority of RFID tags in existence are of the
passive variety. As of 2004 tags cost from US$0.40. The aim is to
produce tags for less than US$0.05 to make widespread RFID tagging
commercially viable. However, chip manufacturers' supply of
integrated circuits is not sufficient and demand is too low for
prices to come down soon. Analysts from independent research
companies like Gartner and Forrester Research agree that a price
level of less than $0.10 is only achievable in 6-8 years, a
potential hurdle to widespread passive RFID adoption.
While the
cost advantages of passive tags over active tags are significant,
other factors including accuracy and reliability make the use of
active tags very common today.
There are
four different kinds of tags commonly in use. They are categorized
by their radio frequency: Low frequency tags (between 125 to 134
kilohertz), High frequency tags (13.56 megahertz), UHF tags (868 to
956 megahertz), and Microwave tags (2.45 gigahertz). UHF tags cannot
be used globally as there aren't any global regulations for their
usage.
See also
for some Transponder devices which deliver a similar function, and
contactless chip cards.
The RFID System (Top)
An RFID
system may consist of several components: tags, tag readers, tag
programming stations, circulation readers, sorting equipment, and
tag inventory wands. Security can be handled in two ways. Security
gates can query the ILS to determine its security status or the tag
may contain a security bit which would be turned on and off by
circulation or self-check reader stations.
The
purpose of an RFID system is to enable data to be transmitted by a
portable device, called a tag, which is read by an RFID reader and
processed according to the needs of a particular application. The
data transmitted by the tag may provide identification or location
information, or specifics about the product tagged, such as price,
color, date of purchase, etc. The use of RFID in tracking and access
applications first appeared during the 1980s. RFID quickly gained
attention because of its ability to track moving objects. As the
technology is refined, more pervasive—and invasive—uses for RFID
tags are in the works.
In a
typical RFID system, individual objects are equipped with a small,
inexpensive tag. The tag contains a transponder with a digital
memory chip that is given a unique electronic product code. The
interrogator, an antenna packaged with a transceiver and decoder,
emits a signal activating the RFID tag so it can read and write data
to it. When an RFID tag passes through the electromagnetic zone, it
detects the reader's activation signal. The reader decodes the data
encoded in the tag's integrated circuit (silicon chip) and the data
is passed to the host computer for processing.
Take the
example of books in a library. Security gates can detect whether or
not a book has been properly checked out of the library. When users
return items, the security bit is re-set and the item record in the
ILS is automatically updated. In some RFID solutions a return
receipt can be generated. At this point, materials can be roughly
sorted into bins by the return equipment. Inventory wands provide a
finer detail of sorting. This tool can be used to put books into
shelf-ready order.
Current usage (Top)
Low-frequency RFID tags are commonly used for animal identification,
beer keg tracking, and automobile key-and-lock, anti-theft systems.
Pets are often embedded with small chips so that they may be
returned to their owners if lost. In the United States, two RFID
frequencies are used: 125 kHz (the original standard) and 134.5 kHz,
the international standard.
High-frequency RFID tags are used in library book or bookstore
tracking, pallet tracking, building access control, airline baggage
tracking, and apparel item tracking. High-frequency tags are widely
used in identification badges, replacing earlier magnetic stripe
cards. These badges need only be held within a certain distance of
the reader to authenticate the holder.
UHF RFID tags are commonly used commercially in pallet and container
tracking, and truck and trailer tracking in shipping yards.
Microwave RFID tags are used in long range access control for
vehicles, an example being General Motors' OnStar system.
Some toll booths, such as California's FasTrak and Illinois' I-Pass
system, use RFID tags for electronic toll collection. The tags are
read as vehicles pass; the information is used to debit the toll
from a prepaid account. The system helps to speed traffic through
toll plazas.
Sensors such as seismic sensors may be read using RFID transceivers,
greatly simplifying remote data collection.
In January 2003, Michelin announced that it has begun testing RFID
transponders embedded into tires. After a testing period that is
expected to last 18 months, the manufacturer will offer RFID-enabled
tires to car-makers. Their primary purpose is tire-tracking in
compliance with the United States Transportation, Recall,
Enhancement, Accountability and Documentation Act (TREAD Act).
Cards embedded with RFID chips are widely used as electronic cash,
e.g. Octopus Card in Hong Kong and the Netherlands to pay fares in
mass transit systems and/or retails.
Starting from the 2004 model year, a "Smart Key" option is available
to the Toyota Prius and some Lexus models. The key fob uses an
active RFID circuit which allow the car to acknowledge the key's
presence within 3 feet of the sensor. The driver can open the doors
and start the car while the key remains in a purse or pocket.
In August 2004, the Ohio Department of Rehabilitation and Correction
(ODRH) approved a $415,000 contract to trial the tracking technology
with Alanco Technologies. Inmates will wear "wristwatch-sized"
transmitters that can detect if prisoners have been trying to remove
them and send an alert to prison computers. This project is not the
first such rollout of tracking chips in US prisons. Facilities in
Michigan, California and Illinois already employ the technology.
Implantable RFID "chips", originally designed for animal tagging are
being used and contemplated for humans as well. Applied Digital
Solutions proposes their chip's "unique under-the-skin format" as a
solution to identity fraud, secure building access, computer access,
storage of medical records, anti-kidnapping initiatives and a
variety of law-enforcement applications. Combined with sensors to
monitor body functions, the Digital Angel device could provide
monitoring for patients. The Baja Beach Club in Barcelona, Spain
uses an implantable Verichip to identify their VIP customers, who in
turn use it to pay for drinks [1] (http://news.bbc.co.uk/2/hi/technology/3697940.stm).
The Mexico City police department has implanted approximately 170 of
their police officers with the Verichip, to allow access to police
databases and possibly track them in case of kidnapping.
Potential uses (Top)
RFID tags
are often envisioned as a replacement for UPC or EAN bar-codes,
having a number of important advantages over the older bar-code
technology. However it is unlikely that RFID tags will replace
barcodes, but more likely that it will be used as a complementary
technology. This is for two main reasons: 1) Cost of tags, 2)
necessity to individually recognize an individual item. The cost of
a tag is still relatively high, but in time this will reduce due to
economies of scale. However, it is unlikely that lower value items
will ever justify any cost associated to tagging it. Also the unique
nature of each tag may be considered to be overkill in being able to
track the final consumer of every can of beans or bag of potatoes.
It must also be recognized that the storage of data associated with
tracking goods down to item level will run into many terabytes. It
is much more likely that goods will be tracked at pallet level using
RFID tags, and at item level with product unique rather than item
unique barcodes.
RFID codes are long enough that every RFID tag may have a unique
code, while current UPC codes are limited to a single code for all
instances of a particular product. The uniqueness of RFID tags means
that a product may be individually tracked as it moves from location
to location, finally ending up in the consumer's hands. This may
help companies to combat theft and other forms of product loss. It
has also been proposed to use RFID for point-of-sale store checkout
to replace the cashier with an automatic system which needs no
barcode scanning. However this is not likely to be possible without
a significant reduction in the cost of current tags. There is some
research taking place into ink that can be used as an RFID tag,
which would significantly reduce costs. However, this is some years
from reaching fruition.
An organization called EPCglobal is working on an international
standard for the use of RFID and the Electronic Product Code (EPC)
in the identification of any item in the supply chain for companies
in any industry, anywhere in the world. The organization's board of
governors includes representatives from EAN International, Uniform
Code Council, The Gillette Company, Procter & Gamble, Wal-Mart,
Hewlett-Packard, Johnson & Johnson, Checkpoint Systems and Auto-ID
Labs. Some RFID systems use alternative standards based on the
ISO-classification 18000-6. The EPCglobal gen 2 standard was
approved in December 2004, and is likely to form the backbone of
RFID tag standards moving forward. This was approved after a
contention from Intermec that the standard may infringe a number of
their RFID related patents. It was decided that the standard itself
did not infringe their patents, but it may be necessary to pay
royalties to Intermec if the tag was to be read in a particular
manner.
In July 2004, the Food and Drug Administration issued a ruling that
essentially begins a final review process that will determine
whether hospitals can use RFID systems to identify patients and/or
permit relevant hospital staff to access medical records.
Also, the FDA recently approved the country's first RFID chips that
can be implanted in humans. The 134.2 kHz RFID chips, from VeriChip
Corp., a subsidiary of Applied Digital Solutions Inc., can
incorporate personal medical information and could save lives and
limit injuries from errors in medical treatments, according to the
company. The FDA approval was disclosed during a conference call
with investors.
Some in-home uses, such as allowing a refrigerator to track the
expiration dates of the food it contains, have also been proposed,
but few have moved beyond the prototype stage.
Another proposed application is the use of RFID as intelligent
traffic signals on the road (Road Beacon System or RBS). More
details in: (http://www.roadbeacon.com).
Regulation and standardization (Top)
There is
no global public body that governs the frequencies used for RFID. In
principle, every country can set its own rules for this. The main
bodies governing frequency allocation for RFID are:
-
USA:
FCC (Federal Communications Commission),
-
Canada: DOC (Department of Communication)
-
Europe: ERO, CEPT, ETSI, and national administrations. Note that
the national administrations have to ratify the usage of a
specific frequency before it can be used in that country
-
Japan: MPHPT (Ministry of Public Management, Home Affairs, Post
and Telecommunication)
-
China: Ministry of Information Industry
-
Oceania: Australian Communication Authority, New Zealand
Ministry of Economic Development
Low
frequency (LF: 125 - 134 kHz and 140 - 148.5 kHz) and High-frequency
(HF: 13.56 MHz) RFID tags can be used globally without a license.
Ultra-high frequency (UHF: 868 MHz-928 MHz) cannot be used globally
as there isn't one single global standard. In North America, UHF can
be used unlicensed for 908 - 928 MHz, but restrictions exist for
transmission power. In Europe UHF is under consideration for 865.6 -
867.6 MHz. Its usage is unlicensed for 869.40 - 869.65 MHz only, but
restrictions exist for transmission power. The North-American UHF
standard (908-928 MHz) is not accepted in France as it interferes
with its military bandwidths. For China and Japan, there is no
regulation for the use of UHF. Each application for UHF in these
countries needs a site license, which needs to be applied for at the
local authorities, and can be revoked. For Australia and New
Zealand, 918 - 926 MHz for unlicensed use, but restrictions exist
for transmission power.
Additional regulations exist regarding health and environmental
issues. For example, in Europe, the WEEE regulation (Waste
Electrical and Electronic Equipment) does not allow for RFID tags to
be thrown away. This means that RFID tags in cardboard boxes have to
be removed before disposing them. Additional health regulations
exist as well, see EMF (Electromagnetic field).
Some
standards that have been made regarding RFID technology include:
Controversy (Top)
"How
would you like it if, for instance, one day you realized your
underwear was reporting on your whereabouts?"
-- California Senator Debra Bowen, at a 2003 hearing
RFID
technology has been subject to controversy. The main concerns relate
to privacy, and include:
* Whether the purchaser of an item will be aware of the presence of
the tag or be able to remove or deactivate it;
* Whether the tag can be read at a distance without the knowledge of
the individual;
* If a tagged item is paid for by credit card or in conjunction with
use of a loyalty card, whether it would be possible to tie the
unique ID of that item to the identity of the purchaser
The standard proposed by EPCglobal includes privacy-related
guidelines for the use of RFID-based EPC. These guidelines include
the requirement to give consumers clear notice of the presence of
EPC and to inform them of the choice that they have to discard,
disable or remove EPC tags. These guidelines are non-binding. See
also ISTPA [5].
|
Copyright (C) 2005 Cisco-Eagle inc. Everyone is
permitted to copy and distribute verbatim copiesof this
license document, but changing it is not allowed. |
