ABSTRACT

          RFID is an automatic wireless data collection technology which uses RF signals for automatic identification of objects by transferring data between a reader and an RF tag to identify, categorize and track….

          Each country has its own frequency allocation for RFID. RFID UHF bands between 865- 867 MHz is the region of interest. In this range (UHF), the operational principle used is Backscatter phenomena (E- field /Far field).

          A typical RFID tag consists of an antenna and an integrated circuit (chip). The tag can be active or passive. The chip obtains power from the RF signal transmitted by the base station called “RFID reader”. RFID tag antenna is loaded with the chip whose impedance switches between two impedance states, usually high and low that is one matched to the antenna ( chip collects power in that state) and another one is strongly mismatched. The tag sends the information back by varying its input impedance and thus modulating the back-scattered signal.