What is RFID ?

Radio frequency identification (RFID) is a generic term that is used to describe a system that transmits the identity (in the form of a unique serial number) of an object or person wirelessly, using radio waves. It's grouped under the broad category of automatic identification technologies.

A basic RFID system consists of three components:

·  An antenna or coil

·  A transceiver (with decoder)

·  A transponder (RFID tag) electronically programmed with unique information. The antenna emits radio signals to activate the tag and to read and write data to it.

·  The reader emits radio waves in ranges of anywhere from one inch to 100 feet or more, depending upon its power output and the radio frequency used. When an RFID tag passes through the electromagnetic zone, it detects the reader's activation signal.

·  The reader decodes the data encoded in the tag's integrated circuit (silicon chip) and the data is passed to the host computer for processing.

Types of RFID Tags:

RFID tags can be either passive, semi-passive (also known as semi-active), or active

Passive: Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the incoming radio frequency signal provides just enough power for the CMOS integrated circuit (IC) in the tag to power up and transmit a response.

Semi-passive: Semi-passive RFID tags are very similar to passive tags except for the addition of a small battery. This battery allows the tag IC to be constantly powered.

Active: Unlike passive and semi-passive RFID tags, active RFID tags (also known as beacons) have their own internal power source which is used to power any ICs and generate the outgoing signal.