MOBILITY RFID: Frequently Asked Questions

n What is RFID?

RFID, a contraction for Radio Frequency Identification, is a generic term for
technologies that use radio waves to automatically identify individual items
over relatively short distances (a few inches to hundreds of feet). RFID is a
proven technology that’s been around since the Second World War.

Radio waves travel through most non-metallic materials, so the RFID tags can
be embedded in packaging or encased in protective plastic for weather-proofing
and greater durability. The technology had been expensive and therefore limited
applications were available. But tags are being made cheaply now.

n What is an
RFID tag?

An RFID tag consists of a microchip that is used to store a serial number
that identifies a product, and some other information. The microchip is attached
to a small antenna that enables the transmission of information to the RFID
reader. Together the chip and the antenna are referred to as an RFID tag or an
RFID transponder.

n What are
active and passive tags?

The electrical power to drive the tag’s communication capability can
either be derived from the incident radiation arriving from the reader or by an
electrical supply source (e.g., a battery) located on the tag.

Tags, which derive their transmitting power from the
radiation impinging on the tag, are known as passive devices. A tag that uses
electric field to power it up is referred to as backscatter or reflective tag
and usually utilizes higher frequencies and achieves longer communication
distances.

When the tag has its own power source for transmission, those
tags are referred to as active tags and can usually achieve even longer distance
communication.

n How does an
RFID system work?

The system consists of a tag and a reader with an antenna, also known as an
interrogator. The RFID reader communicates with a tag through the use of radio
frequency (RF) energy. The reader sends out an RF signal and the tag then
modulates the waves and sends them back to the reader. The reader converts these
new waves into digital data.

In addition to reading the tag, the reader can use RF energy
to write new information to the tag. This enables the user to alter the
information stored in the tag from a distance. The readers can be networked
together so as to provide nearly unlimited coverage for a system.

n How much
information can the tag store?

It depends on the vendor and the application, but typically a passive tag
would carry about 2kB of data — enough to store some basic information about
the item it is on. An active tag, on the other hand, can hold a lot more
information than passive tag.

n How much
will it cost me?

RFID attendance or access control cards are commonplace, and cheap: around Rs 50
to 80 each. Active tags are pricier: $50 to $90, but they’re reusable. The
cost of the entire system is dependent on the application it is being used for.
RFID readers for attendance or access systems start at Rs 25,000.

n Where can I
use it?

The primary applications fall into two basic categories, direct product
identification and carrier identification.

In the former, the tag specifically identifies the item to
which it is attached (e.g., by part number or serial number)

In carrier identification the content is identified manually
(or with a bar code reader) and fed to the control system along with the carrier’s
machine-readable RF "license plate number." Strategically deployed RF
readers enable subsequent load tracking.

Common areas of application include logistics, inventory
control, article surveillance, access control, item tracking and in animal
husbandry.

n Who can I
buy from?

See sidebar: RFID Sources, on page 22.

n Why should I
use RFID?

Most large companies are already using RFID-based attendance or access
control systems. In the supply chain or distribution, RFID makes identification,
location and tracking of items easy and real time. In certain areas the
application has a direct impact on revenue. Gillette is using it to control
shelf stock outs and shoplifting.