| Before RFID can be understood completely,
it is essential to understand how Radio Frequency communication occurs.
RF communication occurs by the transference of
data over electromagnetic waves. By generating a specific electromagnetic
wave at the source, its effect can be noticed at the receiver far from the
source, which then identifies it and thus the information.
In an RFID system, the RFID tag which
contains the tagged data of the object generates a signal containing the
respective information which is read by the RFID reader, which then may pass
this information to a processor for processing the obtained information for
that particular application.
RFID Technologies
Thus, an RFID System can be visualized as
the sum of the following three components:
- RFID tag or transponder
- RFID reader or transceiver
- Data processing subsystem
An RFID tag is composed of an antenna, a
wireless transducer and an encapsulating material. These tags can be either
active or passive. While the active tags have on-chip power, passive tags
use the power induced by the magnetic field of the RFID reader. Thus passive
tags are cheaper but with lower range (<10mts) and more sensitive to
regulatory and environmental constraints, as compared to active tags. An
RFID reader consists of an antenna, transceiver and decoder, which sends
periodic signals to inquire about any tag in vicinity. On receiving any
signal from a tag it passes on that information to the data processor. The
data processing subsystem provides the means of processing and storing the
data. RFID systems can also be differentiated based on the frequency range
it uses. Low-frequency (30 KHz to 500 KHz) systems have short reading ranges
and lower system costs. They are most commonly used in security access,
asset tracking, and animal identification applications. High-frequency (850
MHz to 950 MHz and 2.4 GHz to 2.5 GHz) systems, offering long read ranges
(greater than 90 feet) and high reading speeds, are used for such
applications as railroad car tracking and automated toll collection.
However, the higher performance of high-frequency RFID systems incurs higher
system costs ><10mts) and more sensitive to regulatory and environmental
constraints, as compared to active tags.
An RFID reader consists of an antenna,
transceiver and decoder, which sends periodic signals to inquire about any
tag in vicinity. On receiving any signal from a tag it passes on that
information to the data processor.
The data processing subsystem provides the
means of processing and storing the data.
RFID systems can also be differentiated
based on the frequency range it uses. Low-frequency (30 KHz to 500 KHz)
systems have short reading ranges and lower system costs. They are most
commonly used in security access, asset tracking, and animal identification
applications. High-frequency (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz)
systems, offering long read ranges (greater than 90 feet) and high reading
speeds, are used for such applications as railroad car tracking and
automated toll collection. However, the higher performance of high-frequency
RFID systems incurs higher system costs.
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