RFID Tag Antenna Design And Measurement

As an automatic identification technique with non-contact bidirectional communication wireless radio technology, Radio-frequency identification (RFID) can identify object or exchange data. RFID technology used for identification has many advantages, of which the most potential one is the huge market for RFID system applications. Thanks to the rapid development of electronic techniques and manufacturing technology, the RFID applications based on the wireless and radar techniques emerge rapidly, which will be found very useful in many fields, such as goods stocking and distribution, supply chain, commerce and trade, manufacturing, identification, and security management. As a vital and integral part of RFID system, RFID antennas have received much attention, and their design is very urgent and significant.Since AutoID propose ideas of EPC and Internet of Things,it gains lots of support from enterprise and government,RFID technology grows rapidly after that.To promote RFID technology widespread in our country,grasp the key technology of proprietary intellectual property rights,the government launched a series of study project.In RFID system,one key index is the readable distance,the parameter that decide the distance is RFID reader antenna and tag antenna performance.In this paper,tag antenna design and measuremtns problem in UHF RFID system has been studied, In fact, the development of RFID antenna is of theoretical significance and practical value for the RFID system.First,basic idea about RFID system and technology introduction is presented,some detail antenna characteristic and dipole antenna theory is also there.Main work of this thesis is:(1)discuss antenna in RFID system design task,which is to achieve the maximum readable distance.Then the requirement of conjugate matching condition between RFID chip and antenna is analyzed.(2)several methods of rfid antenna complex impedance implement have been studied, three rfid antennas as T-matching feeded dipole antenna,inductively coupled feeding,adjustable dipole antenna.(3)Problem about small RFID tag antenna measurement is discussed here,inductively coupled feeding dipole antenna has been measured and compared to simulated results,these two results agree with each other well.A newly solution of measuring RFID chip's encapsulated impedance is studied too for further system design job of RFID tag.