Radio-frequency identification

Introduction

Radio-frequency identification (RFID) is a communication technology, that uses electromagnetic waves to identify and track tags. A RFID system consists out of a tag, which is attached to an object, an reader, which extracts the information of the tag and an application, that uses the gathered information.

RFID-System

Reader

A reader is responsible for initiating the communication with a tag, in case of a passive tag the reader also supplies the energy needed to operate the tag. A reader consists out of to components:

1. A control unit
2. A high-frequency interface

Control Unit

The control unit is responsible for

1. Communication with the application
2. Communication with the tag
3. Coding and decoding of the signal
4. Anti-collision algorithm
5. Encryption and decryption of data sent between reader and tag
6. Authentication between reader and tag

The high-frequency interface is responsible for

1. Generation of strong high-frequency signals to activate the tag and supply it with energy
2. Modulating the transmission signal to send data to the tag
3. Receiving the radio frequency signals transmitted by a tag and converting them back into original data