Identification technology designated by the symbol RFID (from the English words Radio Frequency Identification) is referred to in Polish as “identification using radio waves” or “identification by radio signal modulation”. This technology appeared in applications related to product tracking in the 1980s. These wireless systems allow for remote data reading from plastic cards, radio tags, or so-called “tokens” from distances of up to several meters. As a result, they are a complementary method of marking and reading to barcode technology. RFID systems are most effective in industrial environments and other adverse working conditions, as well as wherever barcode reading is not possible due to high dust levels, lack of direct access to the marked object, or the presence of aggressive chemicals.
RFID technology has proven itself in many applications, such as tracking vehicles, pallets, and containers, and even in animal identification.
Every RFID system consists of three basic elements: radio identifiers (RF tags), readers, and control and application software. A radio tag is built from an electronic chip with memory and a miniature antenna, enclosed in a sealed plastic or metal housing. After “illuminating” the token with a beam of electromagnetic radiation from the reader, an induction current is excited in the antenna, which powers the electronic circuit. The circuit generates its unique code, assigned by the manufacturer or user, and sends it to the receiving antenna in the tag reader. In this way, radio tags and the objects marked by them can be identified without the need for physical proximity between the object and the reader, as is often the case with barcode technology. A unique advantage of RFID technology is the ability to repeatedly write information to read-write radio tags and the large memory capacity – up to several thousand bits.
Radio tags come in various shapes and are characterized by different memory sizes, reading distances, and operating conditions. Depending on the needs, radio tag pendants can be used only for reading data or for repeated writing and reading of information. Information carried by radio identifiers allows (depending on the needs) for basic identification or highly complicated and complex applications for controlling moving objects.
Identifiers are divided into two categories based on their power source: active and passive. Batteries are necessary for the operation of active identifiers, while passive ones are powered by an external energy source. Therefore, reading passive transponders can take place over relatively short distances – a maximum of 2 meters. Active transponders can store significantly more information, and they can be read from long distances, even from objects moving at high speeds.
The radio tag reader reads or writes information from/to identifiers via radio waves according to an established data transmission protocol. Each reader is equipped with an antenna, usually with a diameter of several to several dozen centimeters. Antennas for high and low radio frequencies are available. During the reading of passive identifiers, the antenna excites the tag’s electronic circuit for communication.
The article comes from the magazine “Logistyka” 2001/1.