Radio-frequency Identification
Radio-frequency Identification(RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices
called RFID tags or transponders. An RFID tag is an object thar can be applied to or incorporated into a product, animal or person for the
perpose of identification using radiowaves. Some tags can be read from several meters away and beyond the line of sight of the reader .
Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the inoming radio frequency signal
provides just enough power for the CMOS integarated circuit from the reader. This means that the antenna has to be designed to both collect poer fromt he incoming signal and
also to transmit the outbound backscatter signal. The response of a passive RFID tag is not necessarily just an ID number; the tag chip can
contain non-volatile, possibly waitable EEPROM for storing data.
Unlike passive RFID tags, active RFID tags have their own internal power source, which is used to power the
integrated circuits and braoadcast the signal to the reader. Active tags are typically much more reliable (i.e. fewer errors)
than passive tags due to the ability for active tags to coduct a "session" with more reader. Active tags, due to their onboard power suppy,
also transmit ar higher power lecels than passive tags,allowing them to be more effective in "RF challenged"environments like water
(including humans/cattle, which are mostly water), metal (shipping containers, vehicles), or at longer
distances, around).In turn, they are generally bigger and more expensive to manufacture, and their potential shelf life is much shorter.
The antenna used for an RFID tag is affected by the intended application and the frequency of operation. Low-frequency(LF) passive tags are normally inductively coupled, and because the voltage induced is proportional to frequency, ma ny coil turns are needed to produce enough voltage to operate an integrated cuircuit. Compact LF tags, like glass-encapsulated tags used in animal and human identification, use a multilayer coil (3 layers of 100-150 turns each) wapperd around a ferrite core.
Passive
Active
Antenna types
The antenna used for an RFID tag is affected by the intended application and the frequency of operation. Low-frequency(LF) passive tags are normally inductively coupled, and because the voltage induced is proportional to frequency, ma ny coil turns are needed to produce enough voltage to operate an integrated cuircuit. Compact LF tags, like glass-encapsulated tags used in animal and human identification, use a multilayer coil (3 layers of 100-150 turns each) wapperd around a ferrite core.
Hand-Held RFID Motorola
 |
Model No: 3190Z
|
 |
Model No: 9190Z
|
Desktop RFID Motorola
 |
Model No: FX9500
|
 |
Model No: FX7400
|
RFID Antenna Motorola
 |
Model No: AN710
|
 |
Model No: AN720
|
 |
Model No: AN620 |
 |
Model No: AN200
|
Tagging positions
RFID tagging positions can influence the performance of air interface UHF RFID passive tags and related to the position where RFId tags are embedded, attached, injected or digested. In many cases, optimum power from RFID reader is not requied to operate passive tags. However, in cases where the Effective Radio Power(ERP) level and distance between reader and tags are fixed, such as in manufacturing setting, it is important to know the location in a tagged object where a passive tag can operate optimally.
R-Spot or Resonance Spot,L-Spot or Live Spot and D-Spot or Dead Spot are defined to specify the location of RFID tags in a tagged object, where the tags can still recieve power from a reader within specified ERP level and distance.
Product Tracking
The Canadian Cattle Identification Agency began using RFID tags as a replacement for barcode tags. The tags are required to identify a bovine's herd of origin and this is used for tracing when a packing plant condemns a carcass. Currently CCIA tags are used in Wisconsin and by US farmers on a voluntary basis. The USDA is currently developing its own program.
RFID tags used in libraries: square book tag, round CD/DVD tag and rectangular VHS tag. High-frequency RFID tags are used in library book or bookstore tracking, jewelry tracking, pallet tracking,building access control, airline baggage tracking, and apparel and pharmaceutical items tracking. Highfrequencytags 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. The AmericanExpress Blue credit card now includes a high-frequency RFID tag. BGN has launched two fully automated Smartstores that combine item-level RFID tagging and SOA to deliver an integrated supply chain, from warehouse to consumer. UHF RFID tags are commonly used commercially in case, pallet, and shipping container tracking, and truck and trailer tracking in shipping yards.
RFID in inventory systems
An advanced automatic identification technology such as the Auto-ID system based on the Radio Frequency Identification (RFID) technology has two values for inventory systems. First, the visibility provided by this technology allows an accurate knowledge on the inventory level by eliminating the discrepancy between inventory record and physical inventory. In an academic study performed at Wal- Mart, RFID reduced Out of Stocks by 30 percent for products selling between 0.1 and 15 units a day. Second, the RFID technology can prevent or reduce the sources of errors. Benefits of using RFID include the reduction of labour costs, the simplification of business processes and the reduction of inventory inaccuracies.
Replacing barcodes
RFID tags are often envisioned as a replacement for UPC or EAN barcodes, having a number of important advantages over the older barcode technology. They may not ever completely replace barcodes, due in part to their higher cost and in other part to the advantage of more than one independent data source on the same object. The new EPC, along with several other schemes, is widely available at reasonable cost.
The storage of data associated with tracking items will require many terabytes on all levels. Filtering and categorizing RFID data is needed in order to create useful information. It is likely that goods will be tracked preferably by the pallet using RFID tags, and at package level with Universal Product Code (UPC) or EAN from unique barcodes.
Patient identification
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. Since then, a number of U.S. hospitals have begun implanting patients with RFID tags and using RFID systems, more generally, for workflow and inventory management.[30] The use of RFID to prevent mixups between sperm and ova in IVF clinics is also being considered.