What is RFID?
Radio Frequency Identification explained simply
The abbreviation RFID stands for "Radio Frequency Identification". RFID is an automatic identification process that has become widespread in numerous application areas in recent years. It is a contactless communication technology that transmits information for the identification of persons, animals, goods as well as commodities. The use of RFID enables many new applications that could not be realized with conventional identification systems.
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Structure of an RFID-Systems
An RFID system consists of a data carrier (called a transponder or tag) and a read/write device with an antenna. RFID works with weak electromagnetic waves that are emitted by a reader. If a transponder is brought within the range of this antenna, information can be read contactless from the transponder's memory or data can be stored on it.
Transponder types
A distinction is made between passive and active RFID tags. Passive transponders do not have their own power supply and draw their energy directly from the energy field of the reader. This makes passive transponders completely maintenance-free, but the reading ranges are highly dependent on the size of the transponder, the frequency and the antenna. Compared to passive transponders, active transponders are much more complex and have an integrated power supply (battery or accumulator), which makes it possible to achieve much greater reading ranges. Due to the power supply of a battery or accumulator, the lifetime of these transponders is limited, in addition the production costs are many times higher than for passive transponders. Systems with 125kHz, 134.2kHz, 13.56MHz, 868MHz, 915MHz, 2.45GHz are available, which have enormously different reading characteristics and detection ranges.
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Function
The RFID reader generates a weak electromagnetic field via its antenna. If a transponder enters this magnetic field, the microchip of the transponder is supplied with energy and can now send data to the reader without contact or store new information on the chip. If the transponder leaves the reading field, the connection to the reader is broken and the transponder chip is completely inactive again. However, the stored data is still retained in the memory. Complex read/write devices can process many transponders simultaneously by means of an "anti-collision procedure". The electromagnetic waves can penetrate many materials and enable the transponder to be recognized even through packaging.