This chapter provides a survey on radio frequency identification technology (RFID), especially passive RFID technology, which is recommended and highly used in the industrial environment due to its advantages such as low cost of manufacturing and high read range. The chapter reviews the historic of RFID technology, including frequency bands allowed, mode of communications, and different types of RFID TAGs. Then, there is a description of the methodology of passive RFID TAG design and methods used to match input impedance and miniaturization. At the end, a new contribution in passive RFID TAGs design is presented using miniaturization methods such as integration of split ring resonator theory and meander technique.