Rfid Technology and Standards

 




The RFID technology belongs to the Auto-ID tecniques.

RFID stays for Radio Frequency IDentification, i.e. the identification carried on by using a wireless communication.

A RFID system is made up usually by two main parts:

  • The transponder, that's placed on the object to be identified;
  • The reader, which is able to interrogate one or more transponder per cycle, that could operate as a simple reader or - in some case - as a writer.








The reader is usually equipped with a RF transceiver, an external/internal antenna able to transmit and receive energy & data to the transponder(s).

In addition, the reading system are to be connected with external device such as PC, PDA, PLC, SERVER or general purpose control unit, thru many different communication standards (RS 232, RS 485, Ethernet, Wi-Fi..). 

On the other side, the transponder, represents the data storage device,  and it's build with a very small microchip that's connected to a small form factor antenna, placed on the same layer of the chip.

We are considering only passive transponders, i.e. such devices that are completely without battery and that are powered on only by the  electromagnetic field received from the reader's antenna.

It means that if a transponder is placed outside the range of the reader's antenna, it's completely powered off.

The transponder is powered only when it is inside the reader's reading range, that's named coverage area.

The power - supplied only by the electromagnetic field sent by the reader antenna - is converted in electric energy that's used to power on the chip, receive the RF carrier, the Clock impulse and to read/write data from/to the transponder.





Passive tags work on standard frequencies band, such as:

  • LF (Low Frequency Band) @ 125-134 KHz
  • HF (High Frequency Band) @ 13,56 MHz
  • UHF (Ultra High Frequency Band) @ 865-868, 915, 902 MHz (EU, USA, JP)





 

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