The Design Of RFID Tag Antenna Worked On The Metal Surface In UHF Band

In the future, the Internet of Things is the inevitable development tendency. As thefoundation of the Internet of Things, RFID technology is used in modern manufacturingindustry and supply chain management more and more widely. When RFID tag is placedon the surface of metallic object, the metallic environment would have the influence onthe tag antenna performance. Hence a kind of tag antenna applying to metallic surface isresearched in this paper.This project starts from RFID tag antenna basic theory, and researches the basicworking mechanism of RFID system. In the meantime, the basic theory of the dipole tagantenna and microstrip tag antenna are discussed, and the methods of miniaturized dipoleantennas such as bucking dipole are researched, after that the measuring methods of tagantenna are summarized.Meanwhile, the complex permittivity measuring theory of RFID tag substrate isstudied. Waveguide transmission method, rectangle resonant cavity method andmicrostrip line resonance method are researched and make the simulation verification.The measurement systems of three methods are designed, and the feasibility of thesystems is analyzed. Processing the measurement system of the microstrip line resonancemethod, the common RFID tag substrates are measured. On the other hand, a kind ofprinted tag antenna with bucking dipole modal is designed, and the size of antenna is50mm×40mm, and the frequency band of antenna is835MHz-960MHz, thus theantenna has the miniaturization and broadband characteristic. After that, introducing theAMC ground plane, a kind of tag antenna working on the metal surface is designed. Thesize of antenna is84mm×42mm, and the frequency band of antenna is812MHz-927MHz, and the gain of the antenna is2.18dB. The radar cross section (RCS)of the antenna is researched and simulated.