How Does RFID Technology Work?

     RFID is an intelligent application of radio communication technology. Every RFID tag embedded in a product contains an integrated circuit chip (illustrate in the accompanying picture), with memory, which can be used to store information about a product, along with a transponder mechanism, which can transmit this information over a radio carrier wave after encoding and modulating it.

     An RFID tag can either be active or passive. When the tag is powered by a battery to transmit data, it''''s known as an active tag. Passive tags don''''t have on board power to transmit data. They borrow energy from the scanner antenna in the RFID reader to transmit data. An RFID reader consists of a scanning antenna which can receive signals from the tags, decode them and process them for storing it in a database. Here is how a typical RFID tag reading occurs.

      Step 1: RFID Antenna Sends Scanning Signal
An RFID tagged product may either be passed through a reader or scanner or brought into the vicinity of one. Line of sight identification is not necessary in case of RFID technology and the tags are embedded inside a product. The tag reading process begins with the RFID antenna sending a scanning signal which activates the transponder in a tag to respond. The scanning frequency is chosen to match with the transmitting frequency of the transponder.

      Step 2: RFID Tag Transmits Signal
As soon as the active or passive RFID transponder receives the scanning signal, it sends out its own encoded and modulated signal over a radio carrier wave. Active RFID tags can transmit signals over long distances.

      Step 3: Tag Signal is Received, Decoded and Stored
This transmitted signal is received by the reader through its tuned antenna. Subsequently, the signal is demodulated and decoded to register product information in a database. These RFID scanners are attached to computers where this information is stored.

      Bulk identification of products and short scanning time are two of the prime advantages of using RFID tags, instead of bar code labels. RFID tags find varied applications. They have been used to track dwindling populations of animals in the wild. Employee ID cards have built in RFID tags, encased in plastic layers that are used in most corporate and industrial settings nowadays. The US army is one of the biggest patrons of this technology, using it to tag all containers transported worldwide, followed by Walmart which uses the technology in all its retail outlets. RFID chip implants in humans have been used for providing medical history and identification purposes. Hope this article has left no doubt in your mind about how does RFID work to make product identification possible.

LF(125KHZ/134.2KHZ), HF (13.56MHZ) is working with the way of Electronic coupling

UHF (860-928MHZ) ,2.4GHZ Active RFID is Magnetic Coupling.

This feature make the effection of Metal, liquid differently to the specific tag and reader.