Blog

Security systems № 2 (56), 2004
L. Stasenko
The number of publications on this topic does not decrease for several years. This is due to the rapid development of the RFID technology itself, the development of new frequency bands, the regular appearance of new products and new applications, where the technology of contactless identification (or radio frequency identification - Radio Frequency IDentification) allows us to solve problems previously impossible for hardware and software.
From chaos to order, or background
The radio frequency identification technology came into being about 20 years ago and the entire period was shaped at a pace ahead of computer technology. Particularly intense RFID has been improved in the last 5-7 years. This can be explained by two factors: firstly, the development of microelectronics allowed to implement many ideas previously unavailable for purely technological reasons, and secondly, there were standards, the use of which ensured compatibility of technical solutions from different manufacturers. Before considering the specific issues of the use of contactless identification in various areas of human activity, let us dwell on the general principles of RFID systems and regulatory documents that define and will determine in the near future the course of design ideas.

Wal-Mart has long advised its customers to closely monitor the price cuts for its products, and today this world's largest retailer is following price cuts ... for radio frequency identification (RFID) systems. At the end of last year, she announced the mandatory transition of her stores to the RFID system. Since then, the price of RFID tags has halved, which, according to the company's specialists, will lead to a revolution in the world of retail and a complete change in supply chains. The largest Wal-Mart suppliers were asked to switch to RFID tags in their packages by January of next year. Suppliers of this largest retailer strive to meet deadlines, creating a real boom in the RFID market. Some analysts estimate that Wal-Mart alone will soon need a billion RFID chips per year, and the demand for these tiny devices will only grow. Other large retailers and some government agencies now require their partners to attach RFID tags to all types of packaging. So, in November last year, the US Department of Defense approved a new identification system at the federal level, requiring its suppliers to install RFID labels on industrial parts and pallets by 2005.

Radio Frequency Identification technology (RFID - Radio Frequency Identification) is based on the exchange of information between a radio response, one way or another connected with an object, and a polling device (reader) emitting a continuous or pulsed radio signal through an antenna. When a radio responder, called a radio tag, or a tag, passes through the reader’s reading zone, it changes its signal in a certain way and returns it. Reader determines the difference between the emitted and received signals and sets the identifier of the RFID tag in this way. The radio tag consists of a charger, a transceiver with an antenna, a control unit and a power source (if the label is active). In the absence of a power source (passive label), electricity is supplied from the signal charging the capacitor built into the RFID tag. Depending on the type of memory, tags can be read only or read / write. The distance at which information is read and written varies from a few millimeters to a few meters, depending on the technology used. RFID tags themselves are also quite different - in the form of credit cards, implanted microchips in glass cases or large tags that are attached to huge containers. RFID tags use a specific set of frequencies. The most common low-frequency tags operating at frequencies from 125 to 500 kHz. Mid-frequency devices use 27 and 430-440 MHz, and high-frequency devices use 860-915 MHz, 2.45 GHz (for containers and on railways) and 5.8 GHz (for high-speed vehicles). There is a tendency of wider use of high frequencies both for the purpose of unloading the used frequency range and for increasing the transmission speed. With the appropriate housing, radio tags operate in a wide range of environments. They are sensitive to very high temperatures and thermal shocks. In the cold passive RFID tags work better. It is necessary to note the factor of metal proximity to the tag. The low frequency signal is distorted and attenuated by the presence of a metal, especially containing iron. The RFID tag should not be placed in a full metal case, unless it is part of the antenna system. Microwave labels do not get upset, but in the presence of a significant amount of metal to minimize the effect of reflection require carefully calibrated layout.

From the digital home, according to the CeBIT exhibitors, the average person should move to the digital store. The largest German retailer Metro Group (in Russia operates the Metro Cash & Carry network) at CeBITe presented its concept of a “store of the future”, based on the ubiquitous use of RFID (RadioFrequency IDentification) technology - radio frequency identification. All products in this store have a special label in the form of a small piece of foil, similar to a postage stamp and containing a small chip on which information about the product is recorded. (This may be just a digital code, like on bar codes, and more detailed information about the expiration date, storage conditions, etc.) Such a label is capable of “responding” to the reader signals. When arriving at the warehouse, pallets of goods pass by the gate with a scanner, and the system checks on the fly whether the goods that were ordered, arrived at the warehouse, what storage conditions are required for them, what is the shelf life, etc.