14-11-2012, 01:31 PM
Understanding Radio Frequency IDentification (RFID)
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INTRODUCTION TO RFID
RFID is a technology that offers many more benefits compared to other identification technologies such as bar coding and magnetic stripe.
This emerging technology is not new in fact; it is currently being used, in numerous applications throughout Canada and the world. Originally, implemented during World War II to identify and authenticate allied planes, this was known as Friend or Foe. RFID is still being used today for the same purposes.
The main component of this technology is the transponder/tag1, which in most cases comprises of a chip and antenna mounted onto a substrate or an enclosure. The chip consists of a processor, memory and radio transmitter. These transponders communicate via radio frequency to a reader, which has its own antennas. The readers can interface through wired or wireless medium to a main computer. Transponders are also known as smart or radio tags. The memory will vary, depending on the manufacturer, from just a few characters to kilobytes.
Transponders can either be Read Only (R/O) which are pre-programmed with a unique identification or they can be Read Write (R/W) for applications that require data to be stored in the transponder and can be updated dynamically. Another form of transponder is Write Once Read Many times (WORM). This will allow for an identification number to be written to the transponder once. The information is stored in the memory, it cannot be changed but the transponder can be read many times.
The two most common types of RFID technologies are Active and Passive. Active RFID transponders are self powered and tend to be more expensive than Passive. Having power on board allows the tag to have greater communication distance and usually larger memory capacity. The most common application for Active RFID is for highway tolls such as the Highway 407 in Toronto.
As for Passive RFID transponders, which are available with chips and without chips, they have no internal power source therefore require external power to operate. The transponder is powered by an electromagnetic signal that is transmitted from a reader. The signal received will charge an internal capacitor on the transponder, which in turn will then supply the power required to communicate with the reader.
LOW FREQUENCY (LF) PASSIVE RFID
Passive LF RFID has been utilized in several industries for many years. The most common frequencies used are 125 and 134.2 kHz.
One of the key features of LF RFID is that it is not as affected by surrounding metals. This makes it ideal for identifying metal items such as vehicles, equipment, tools and metal containers. The reading range can vary from a few centimeters to a couple of meters depending on the size of the transponders and the reader being used.
Transponders come in various form factors, from glass transponders, to wedge and disks of various sizes. Other form factors available are cards and cylindrical. These different form factors allow for the transponder to be embedded into most materials, except for metal. Other form factors such as keyfobs can also be customized.
LF RFID also penetrates most materials, such as water and body tissue. The limitations are that if used in industrial environments, electric motors may interfere with the LF system.
Due to the size of the antenna required, the LF transponders are typically more expensive than High Frequency transponders. This limits the frequency to applications
HIGH FREQUENCY (HF) PASSIVE RFID
Passive High Frequency (HF) operates at 13.56MHz and is a globally accepted frequency. This means that any system operating at HF can be used globally. However, there are some differences with regulations in the different regions of the world. These differences pertain primarily to power and bandwidth. In North America, Industry Canada and the FCC limits the reader antenna power to three watts while in Europe the regulations allow for four watts.
HF is also the basis of numerous standards such as ISO 14443, 15693, 18000-3. These standards and others will be discussed in more detail in the section V on RFID STANDARDS.
With HF, the signal travels well through most materials including water and body tissue. It is however more affected by surrounding metals compared to Low frequency (LF).
In comparison to LF, the benefits of HF are lower tag costs, better communication speed and the ability to read multiple tags at once.
The length of the antenna is based on the length of the signal wave thus the higher the frequency the shorter the wavelength. For this reason, there is the flexibility that an antenna for a HF tag is small enough that it can be produced by printing it onto a substrate, using conductive ink and then affixing the chip.
Today the cost for HF tags or what are also known as INLAYS is approximately $0.70 to $0.80 CDN. As demand increases, we should see prices drop significantly.
Tags produced with HF chips are typically less than .1mm in thickness and are available with different sizes of antennas. The larger the tag antenna, the greater the energy capture area the tag has and the greater the communication distance from the reader. Smaller tag sizes may be easier to package into a product but the downside is the reduction of communication distance available.
The capability of the small inlay size allows for it to be embedded into labels. Labels with inlays are called smart labels. Through the use of printers with embedded RFID or external readers, smart labels can not only be printed on; they can also be written to.
ULTRA HIGH FREQUENCY (UHF) PASSIVE RFID
Ultra High Frequency is referred to the frequency range 300 MHz to 3 GHz in the radio spectrum. RFID technology has been developed in different regions of this band, specifically, 433 MHz, 860 -956 MHz and 2.45 GHz. The focus of this article will be specifically on the 860-956 MHz range due to the fact that this range has attracted most R & D investments and is positioned to dominate the UHF passive RFID market space.
UHF coming to prominence in the RFID market place is a fairly recent phenomena compared to the more established High Frequency (13.56 MHz) and Low Frequency (125-134.2 kHz) technologies. HF is a robust technology, which works well for item management applications, but fails where read ranges of beyond 1m is required. UHF vendors are targeting the supply chain market where longer read distances are required.
[attachment=39402]
INTRODUCTION TO RFID
RFID is a technology that offers many more benefits compared to other identification technologies such as bar coding and magnetic stripe.
This emerging technology is not new in fact; it is currently being used, in numerous applications throughout Canada and the world. Originally, implemented during World War II to identify and authenticate allied planes, this was known as Friend or Foe. RFID is still being used today for the same purposes.
The main component of this technology is the transponder/tag1, which in most cases comprises of a chip and antenna mounted onto a substrate or an enclosure. The chip consists of a processor, memory and radio transmitter. These transponders communicate via radio frequency to a reader, which has its own antennas. The readers can interface through wired or wireless medium to a main computer. Transponders are also known as smart or radio tags. The memory will vary, depending on the manufacturer, from just a few characters to kilobytes.
Transponders can either be Read Only (R/O) which are pre-programmed with a unique identification or they can be Read Write (R/W) for applications that require data to be stored in the transponder and can be updated dynamically. Another form of transponder is Write Once Read Many times (WORM). This will allow for an identification number to be written to the transponder once. The information is stored in the memory, it cannot be changed but the transponder can be read many times.
The two most common types of RFID technologies are Active and Passive. Active RFID transponders are self powered and tend to be more expensive than Passive. Having power on board allows the tag to have greater communication distance and usually larger memory capacity. The most common application for Active RFID is for highway tolls such as the Highway 407 in Toronto.
As for Passive RFID transponders, which are available with chips and without chips, they have no internal power source therefore require external power to operate. The transponder is powered by an electromagnetic signal that is transmitted from a reader. The signal received will charge an internal capacitor on the transponder, which in turn will then supply the power required to communicate with the reader.
LOW FREQUENCY (LF) PASSIVE RFID
Passive LF RFID has been utilized in several industries for many years. The most common frequencies used are 125 and 134.2 kHz.
One of the key features of LF RFID is that it is not as affected by surrounding metals. This makes it ideal for identifying metal items such as vehicles, equipment, tools and metal containers. The reading range can vary from a few centimeters to a couple of meters depending on the size of the transponders and the reader being used.
Transponders come in various form factors, from glass transponders, to wedge and disks of various sizes. Other form factors available are cards and cylindrical. These different form factors allow for the transponder to be embedded into most materials, except for metal. Other form factors such as keyfobs can also be customized.
LF RFID also penetrates most materials, such as water and body tissue. The limitations are that if used in industrial environments, electric motors may interfere with the LF system.
Due to the size of the antenna required, the LF transponders are typically more expensive than High Frequency transponders. This limits the frequency to applications
HIGH FREQUENCY (HF) PASSIVE RFID
Passive High Frequency (HF) operates at 13.56MHz and is a globally accepted frequency. This means that any system operating at HF can be used globally. However, there are some differences with regulations in the different regions of the world. These differences pertain primarily to power and bandwidth. In North America, Industry Canada and the FCC limits the reader antenna power to three watts while in Europe the regulations allow for four watts.
HF is also the basis of numerous standards such as ISO 14443, 15693, 18000-3. These standards and others will be discussed in more detail in the section V on RFID STANDARDS.
With HF, the signal travels well through most materials including water and body tissue. It is however more affected by surrounding metals compared to Low frequency (LF).
In comparison to LF, the benefits of HF are lower tag costs, better communication speed and the ability to read multiple tags at once.
The length of the antenna is based on the length of the signal wave thus the higher the frequency the shorter the wavelength. For this reason, there is the flexibility that an antenna for a HF tag is small enough that it can be produced by printing it onto a substrate, using conductive ink and then affixing the chip.
Today the cost for HF tags or what are also known as INLAYS is approximately $0.70 to $0.80 CDN. As demand increases, we should see prices drop significantly.
Tags produced with HF chips are typically less than .1mm in thickness and are available with different sizes of antennas. The larger the tag antenna, the greater the energy capture area the tag has and the greater the communication distance from the reader. Smaller tag sizes may be easier to package into a product but the downside is the reduction of communication distance available.
The capability of the small inlay size allows for it to be embedded into labels. Labels with inlays are called smart labels. Through the use of printers with embedded RFID or external readers, smart labels can not only be printed on; they can also be written to.
ULTRA HIGH FREQUENCY (UHF) PASSIVE RFID
Ultra High Frequency is referred to the frequency range 300 MHz to 3 GHz in the radio spectrum. RFID technology has been developed in different regions of this band, specifically, 433 MHz, 860 -956 MHz and 2.45 GHz. The focus of this article will be specifically on the 860-956 MHz range due to the fact that this range has attracted most R & D investments and is positioned to dominate the UHF passive RFID market space.
UHF coming to prominence in the RFID market place is a fairly recent phenomena compared to the more established High Frequency (13.56 MHz) and Low Frequency (125-134.2 kHz) technologies. HF is a robust technology, which works well for item management applications, but fails where read ranges of beyond 1m is required. UHF vendors are targeting the supply chain market where longer read distances are required.