Radio Frequency Identification (RFID) is an automatic identification
technology that uses radio frequency without human interactions.
The frequency bands used currently vary over different countries.
For example, Hong Kong SAR has approved, in April 2005, two
bands 920-925 MHz and 865-868 MHz for RFID use. The band in
between is currently used for other telecommunication device
(in this case, GSM). This is typical of few other countries
that the allocated frequency bands are split or just one of
the two as that in Hong Kong.
Anyhow, RFID has been used for a long time since WWII but
not until recently, its applications were generally found
in vertical markets with proprietary technologies. With the
advent when the matured barcode system started to run out
of numbers and the call for higher efficiency in a supply
chain, a research group in MIT sponsored by a number of technology
companies and industrial giants like Gillette and P&G
set up the Auto-ID center in late 1999 with the ambition to
create the next-generation asset-management system using RFID
and the concept of a number that can be uniquely identifiable
in the world. The outcome is a set of RFID standards and the
Electronic Product Code (EPC). These technologies were then
transferred to and commercialize by the non-profit making
organization EPCglobal Inc. in October 2003.
At its early stage, RFID is not intended to replace the bar
code system. Under the EPCglobal picture, a RFID system has
3 components, the reader, the tag and the support information
infrastructure. By using the minimalist approach, the tag
contains only the EPC information which would occupy 64 or
96 bits of memory space in the current generation and keeping
the price to its minimal. Information related to a specific
EPC will then be stored in the information infrastructure
and this creates an internet of things. With the upcoming
256-bit version, it has been claimed that the numbering system
is large enough to assign each molecule on the Earth a unique
number. The immediate problem is to ensure most, if not all,
existing trade codes offered by different standards organization,
can be encapsulated within EPC. It will take some times before
a consensus and a final blueprint can be reached for global
A tag is an electronic device that is used to attach to movable
items. There are two kinds of tags, active and passive. An
active tag has its power source built-in and because of this,
the tag has the capability to transmit a signal to a longer
distance, generally in hundred meter range. And because of
a more constant supply of power, an active tag generally has
more logics or intelligence built in. This enables it to do
tasks like encryption and data collection. The downside of
an active tag is its physical size and limited life-span,
due to the battery. On contrary, a passive tag derives (or
harvests) power from magnetic induction or radiate the modulated
incoming electromagnetic waves by power reflection via its
antenna. No battery is built onboard. This gives the tag a
very long life span but due to the limited strength of the
power that the antenna can radiate, a passive tag can only
transmit up to 5 meters using the 915MHz frequency band and
down to only a few centimeters when using the 13.5MHz band.
Physical construction of a tag consists of a chip, an antenna
and the inlay. The chip is the place where information in
digital form is stored. Size of the chip is proportional to
the number of logic gates on it. The more the number of logic
gates, the bigger is the chip size. The physical appearance
of the chip is as small as a grain of sand. Some may even
be described as dust.
Antenna on a tag is for receiving and transmitting signals.
It is the size of the antenna that determines the size of
a tag. Antennas can be designed to suit specific applications
and environments. On passive tags using magnetic induction
as the method for power delivery, the strength of power that
can be induced on a tag depends on the effective area the
antenna exposed to the power generating field. Tag antennas
are manufactured by copper etching process or printing process
and they are attached to the chip with the physical support
of the inlay. Due to the cheaper cost, passive RFID tags will
be the used for item tagging in supply chain applications.
A RFID reader is an electronic
device that sends command signals to and read back the emitted
signals from tags. If the tag is a passive one, the reader
is also responsible to deliver the magnetic field or the source
of the reflected power. If a reader has the capability to
write data to writable tags, it is called as an “interrogator”.
A reader has an antenna or an antenna system. The power emitting
capability of the reader determines the longest distance that
a passive tag signal can be read. Generally, the maximum power
that can be radiated by a device using the ISM bands is regulated
by government. For example, in USA, FCC allows the maximum
radiated power up to 2W before a special license is required.
Under such condition, sensitivity of the reader in turn determines
the maximum distance where a passive tag signal can be detected
reliably. After reading the tag data, the reader will pass
it to the backend support system for intended purposes.
The significant difference between EPC-RFID and barcodes
is EPC-RFID can provide identification of assets (referred
generally as products in supply chain domain) down to individual
item level (e.g., two cans of soda would not be distinguished
with the current barcode on each - the barcode now only identifies
the class of product). This is due to the elasticity of the
storage of a very large number on tag, allowing labeling of
enormous ranges. Here we list some perceived benefits of RFID
RFID technology does not require the line
of sight as it does in the optical bar code system. This
reduces labor cost, time and possibly storage space as
required for barcode scanning.
RFID technology is inert to dirt, water
damage and less prone to other damage as it happens to
the bar code system. This reduces labor cost, material
cost and time on repairing barcode labels.
RFID tags can be read in tens per second
range. This is way higher than the optical barcode system.
Time will be reduced and efficiency will be increased.
RFID tags can be read without human intervention
and by following standards, can be read by any standard-compliant
In a factory, RFID can be used to automate
the inventory management system and manufacturing process
In a supply chain, RFID enables a closer
tracking of products from shipment to shop floor. By sharing
the information, better coordination can be done.
In a retail shop, RFID offers the capability
to do automatic check out, automatic shelf refill. This
reduces customer complaints and their time on queuing.
RFID technology has the inherited capability
to do Electronic Article Surveillance (EAS). Cost on managing
a separate EAS system as in using barcodes will be eliminated
RFID can also be used for authentication
and as a way to identify genuine articles. This can help
to fight the counterfeit problem.
Due to the track-and-trace and authentication
capability, RFID can help to fight gray market or parallel
imports. It also helps to handle consumer returns or after
sale support without receipts. This delivers better customer
service and then, promoting brand loyalty
In conjunction with EPC, RFID offers
the capability of real time tracking of products to the
item level. This gives the supply chain a higher visibility
on product movement and on product inventory. This helps
to reduce the out-of-stock problem.
With the flexibility of writing company
or product specific information onto the tag, RFID tags
will serve as the pivot point where capabilities of future
smart home appliances like smart washing machine, smart
fridge will be leverage to the next level.
EPC-RFID is fully supported and backed
by Department of Defense, big retailer chains like Wal-Mart
in the US, Metro in Germany, Tesco in the UK and big manufacturers
like Gillette and P&G.
RFID can be rolled out in different phrases
and progressively according to the business needs without
too many risks in dealing with coherence to current business
processes and technical compatibility issues in the future.
RFID can first be deployed at pallet level and proceed
to the item level when tag price comes down. RFID does
not mean to be a total replacement of barcodes overnight.
The apparel industry is a good candidate
to take full benefit from using RFID technology due to
its inherited advantage. Garment materials do not create
problems for the RFID system as do in, for example, the
soft-drink industry where water and metal complicate the
propagation of electro-magnetic waves.