10-04-2012, 04:38 PM
THE RFID TECHNOLOGY AND ITS CURRENT APPLICATIONS
RFID_MITIP2006.doc (Size: 460 KB / Downloads: 31)
INTRODUCTION
Although the foundation of the Radio Frequency Identification (RFID) technology was laid by past generations, only recent advances opened an expanding application range to its practical imple- mentation.
RFID is only one of numerous technologies grouped under the term Automatic Identification (Auto ID), such as bar code, magnetic inks, optical character recognition, voice recognition, touch mem- ory, smart cards, biometrics etc. Auto ID technologies are a new way of controlling information and material flow, especially suitable for large production networks.
The RFID technology is a means of gathering data about a certain item without the need of touch- ing or seeing the data carrier, through the use of inductive coupling or electromagnetic waves. The data carrier is a microchip attached to an antenna (together called transponder or tag), the latter enabling the chip to transmit information to a reader (or transceiver) within a given range, which can forward the information to a host computer. The middleware (software for reading and writing tags) and the tag can be enhanced by data encryption for security-critical application at an extra cost, and anti-collision algorithms may be implemented for the tags if several of them are to be read simultaneously.
Advantages
Though RFID is not likely to entirely replace commonly used barcodes in the near future, the fol- lowing advantages suggest to additionally apply RFID for added value of identification:
ƒ Tag detection not requiring human intervention reduces employment costs and eliminates hu-
man errors from data collection,
ƒ As no line-of-sight is required, tag placement is less constrained,
ƒ RFID tags have a longer read range than, e. g., barcodes,
ƒ Tags can have read/write memory capability, while barcodes do not,
ƒ An RFID tag can store large amounts of data additionally to a unique identifier,
ƒ Unique item identification is easier to implement with RFID than with barcodes,
ƒ Tags are less sensitive to adverse conditions (dust, chemicals, physical damage etc.),
ƒ Many tags can be read simultaneously,
ƒ RFID tags can be combined with sensors,
ƒ Automatic reading at several places reduces time lags and inaccuracies in an inventory,
ƒ Tags can locally store additional information; such distributed data storage may increase fault
tolerance of the entire system,
ƒ Reduces inventory control and provisioning costs,
ƒ Reduces warranty claim processing costs.
Current issues of concern, limitations
Although many RFID implementation cases have been reported, the widespread diffusion of the technology and the maximum exploitation of its potential still requires technical, process and secu- rity issues to be solved ahead of time. Today’s limitations of the technology are foreseen to be overcome and specialists are already working on several of these issues.
Collision
Attempting to read several tags at a time may result in signal collision and ultimately to data loss. To prevent this, anti-collision algorithms (most of them are patented or patent pending) can be ap- plied at an extra cost. The development of these methods, aimed at reducing overall read time and maximizing the number of tags simultaneously read, still goes on [3].
Frequency
The optimal choice of frequency depends on several factors, such as:
a.) Transmission mode. RFID tags basically use two kinds of data transmission, depending on the behavior of electromagnetic fields at the frequency used. In lower frequencies (such as 125–
134kHz in the LF band or 13.56MHz in the HF band), inductive coupling is used, while in frequency bands above (UHF with typical frequency ranges of 433MHz, 865–956MHz and 2.45GHz), wave backscattering is the main means of transmission. This also affects the safe reading range, as it is easier to build direction-selective devices with a longer read range in higher frequencies. This may restrict design freedom if either reading range or spatial selectivity are an important issue.
CONCLUSION
The paper gave an overview of the current state and trends of RFID technology. Even though nu- merous limitations and unresolved issues still hinder the widespread application of RFID, it can be already seen that especially enterprises in complex supply chains will benefit from RFID, once the application difficulties are overcome.