Based On Different Objects Rfid Tag Antenna

As a contactless automatic identification technique, the research of radio frequeney identification(RFID) technologye develop rapid. RFID technique has been applied in many fields , such as transportation control , safety control, automatic pipeline production, goods control and so on. Performance of RFID tag antenna is unstable in different environments. The design of stable tag is one of the key techniques of RFID system.Based on the research of available RFID antennas, a new design of UHF band and 2.45GHz backscatter modulation RFID tag antenna for multi-application is proposed in this paper.This paper contains three parts:Firstly, performance of dipole-type RFID tag on different materials is discussed by using software HFSS. For example, the performance of tag in the air is different from on the metal . The conclusion of dipole-typed tag antennas can not work for multi-application is obtained.Secondly, this paper introduce the theory of the microstrip antenna.As an important theory of RFID tag antenna design, compact and broadband technology of microstrip antennas is discussed as well.The part describe the process of design UHF band RFID tag antenna for multi-application,just including the choice of substrate, the methods for impedance matching between microstrip RFID tag antennas and tag ICs, improving the design of RFID tag based on the compact and broadband technology of microstrip antennas.Thirdly, the 2.45GHz band RFID tag antenna microstrip dual array antenna based on the theory of microstrip antenna array is designed. In order to reduce the size of binary arrays, the coupling feeding is selected to instead of parallel feeding. Simulation of coupling feeding 2.45GHz RFID tag antenna for multi-application is completed.Both UHF band RFID tag and 2.45GHz RFID tag are fabricated and tested. The measured readable distance of the UHF band tag antenna achieve 4m in air,higher than 3.5m on the metallic objects; The readingranges of 2.45GHz band tags are 8m in air, compareing 7.8m on the metallic objects.The results show that the proposed antenna has good performance for multi-application.