Interesting ! We see this in our daily life and the best application used in shopping mals,you want know what it is?

                                   Radio Frequency Identifier (RF-ID) Tag

Introduction:

Radio-frequency identification (RF ID) is the wireless use of electromagnetic fields to transfer data, for the purposes of automatically identifying and tracking tags attached to objects. The tags contain electronically stored information ,it contains memory chip.

Some tags are powered by electromagnetic induction from magnetic fields produced near the reader. Some types collect energy from the interrogating radio waves and act as a passive transponder. Other types have a local power source such as a battery and may operate at hundreds of meters from the reader.

Note:

Unlike a barcode, the tag does not necessarily need to be within line of sight of the reader, and may be embedded in the tracked object. Radio frequency identification (RF ID) is one method for Automatic Identification and Data Capturing(AIDC) i.e., it can be used when the object in motion ,while barcode does not.

HOW:

In a basic RF ID system, tags are attached to all items that are to be tracked. These tags are made from a tiny tag-chip, sometimes called an integrated circuit (IC), that is connected to an antenna that can be built into many different kinds of tags including apparel hang tags, labels, and security tags, as well as a wide variety of industrial asset tags. The tag chip contains memory which stores the product's electronic product code (EPC) and other variable information so that it can be read and tracked by RF ID readers anywhere.

RFID reader:

An RF ID reader is a network connected device (fixed /movable) with an antenna that sends power as well as data and commands to the tags. The RF ID reader  access RF ID tagged items so that the tags' data can be made available to business applications as many.

Structure of RF ID tag:

An RF ID tag is comprised of an integrated circuit attached to an antenna that has been printed, etched, stamped or vapor-deposited onto a mount which is often a paper substrate or PolyEthylene Therephtalate (PET). The chip and antenna combo, called an inlay, is then converted or sandwiched between a printed label and its adhesive backing or inserted into a more durable structure.

Tag chip:

The tag's chip or integrated circuit (IC) delivers performance, memory and extended features to the tag. The chip is pre-programmed with a tag identifier (TID), a unique serial number assigned by the chip manufacturer, and includes a memory bank to store the items' unique tracking identifier (called an electronic product code or EPC).

Electronic Product Code (EPC):

The electronic product code (EPC) stored in the tag chip's memory is written to the tag by an RF ID printer and takes the form of a 96-bit string of data. The first eight bits are a header which identifies the version of the protocol. The next 28 bits identify the organization that manages the data for this tag; the organization number is assigned by the EPCglobal consortium. The next 24 bits are an object class, identifying the kind of product; the last 36 bits are a unique serial number for a particular tag. These last two fields are set by the organization that issued the tag. The total electronic product code number can be used as a key into a global database to uniquely identify that particular product.

One of the Application:

                                                                RF ID locker