RFID SYSTEM
RFID Systems
Radio-frequency identification (RFID), in telecommunications and electronic, we mean a technology for the identification and / or automatic storage of information relating to objects, animals or people (automatic identifying and data caputer, AIDC) based on the ability to store data by particular electronic labels, called tags (or event transpornders or electronic and proximity keys), and on their ability to respond to remote interrogation by specific fixed or portable devices, called readers (or event interrogators).
This identification takes place by radio frequency, thanks to which a reader is able to communicate and / or update the information contained in the tags it is querying; in fact, despite its name, a reader (id “reader”) is not only able to read, but also to write information. In a sens, RFID devies can therefore be assimilated to wireless reading and / or writing systems with various applications. In recent years, the NFC standard (Near Field Communication, 13.56 MHz and up to 10 cm, but with data transmission speeds of up to 424 kbit/s) is gradually establishing itself, which extends the standard to allow the exchange of information also among reader.
Specifically, an RFID system consists of three basic elements:
- One or more RFID tags (or tags or transponders);
- A reading and/or writing device (reader);
- A data management informations sytem for the transfer of data to and from readers.
The main element that characterizes an RFID system is the RFID label or transponder or tag, which consists of: a microchip that contains data in a memory (including a universal unique number written in silicon), an antenna, a physical support which holds together the chip and the antenna called “substrate” and which can be made of Mylar, plastic film (PET, PVC, etc.), paper or other materials.
The RFID tag can be active, passive, semi-passive or semi-active. In passive RFID, the tags receive the energy necessary to operate from the RF field provided by the reading system, with a limited reading distance (up to 10-15 m).
A system with passive RFID technology can operate in low frequency (LF), high (HF) or very high frequency (UHF and VHF):
- Passive RFID LF (125-135 KHz): usable worldwide with limited reading distance and applied for anti-theft devices, keys, etc.
- Passive RFID HF (13.56 MHz), normalized by the ISO 14443 and ISO 15693 standards; it is used worldwide, with a reduced reading distance (up to 1.20 m) and applied for books, pallets, access control, clothing etc.
- UHF passive RFID (868 – 915 MHz): meets local limits defined by the authorities of individual countries, applied for pallets, containers, etc.
- VHF (2.4 or 5.8 GHz): used globally for active transponders, applied for access control, vehicles, tec.
- In the active RFID, however, the tags live on their own power supply, normally consisting of a long-lasting battery: when interrogated by the reading system, the tags emit their own radio-requency energy capable of propagating over longer distances substantial; Using advanced radio transmission technology in the UHF band, Active RFID devices transmit and receive data at distances up to 100 meters (Tag i-B2) or up to 500 meters with tags from the i-Q350 family.
RFID Reader
The reader emits and electromagnetic / electric field which, through the induction process, generates a current in the tag antenna that feeds the chip. The chip thus fed communicates all its information that is radiated through the antenna towards the reader and the reader, as mentioned several times, can also write the data on the tag.
The antenna receives a signal, which through the principle of induction transforms it into electricity, which feeds the microchip. The chip thus activated transmits the data contained therein via the antenna (signal transmission circuit) to the apparatus that receives the data. In summary, an RFID tag is able to receive and transmit via radio frequency the information contained in the chip to an RFID transceiver.
Advantages compared to barcode and magnetic stripes
RFID technology has some simple advantages over traditional barcode and magnetic stripe technologies:
- It does not have to be in contact to be read like magnetic strips;
- It does not have to be visible to be read as for bar codes;
- You can also add information on the chips according to the type of chip (Read Only: you can only read the information contained, Write Once, Read Many: you can write the information in the chip only once, but read it an unlimited number of times , Read and Write: information can be read and stored for a limited but large number of times);
- Identification and verification take place in 1/10 of a second;
Communication can be unencrypted or encrypted.