RFID Nameplate Tag Design For Pressure Testing Of Pressure Equipment

With the development of the economy,the number and scale of China’s pressure-bearing equipment is increasing year by year.In order to solve the ensuing safety problems of the equipment,the state requires the equipment to pass the pressure resistance test under the supervision of special inspectors before leaving the factory,and introduces radio frequency identification(RFID)tags to store the pressure resistance test data.However,commercially available metal-resistant tags are generally large and subject to environmental influences,so it is necessary to design RFID tags suitable for pressure testing of pressure-bearing equipment,which need to be resistant to high temperatures and metals.The main research elements of this paper are as follows.(1)For the phenomenon of high temperature and high humidity environment inhibiting the performance of RFID tags during the pressure resistance test of pressurebearing equipment,a structure of media buried nameplate tags is proposed.Through electromagnetism theoretical research,the performance of the tag antenna is analyzed by the buried medium,and it is concluded that the temperature change leads to a slight change in the permittivity tolerance of the material,thus causing a change in the operating frequency of the microstrip antenna on a thin substrate,based on this conclusion and other design requirements,the selection of the buried medium and the determination of the structure of the nameplate tag are carried out.(2)A microstrip antenna-based RFID antenna for metal-resistant tags was designed.For the large size of rectangular microstrip antennas,embedded and bent wire structures are introduced into the tag antenna.For the phenomenon of small input resistance of planar tag antenna,the principle of slit antenna is studied and the conclusion that the slit structure has higher resistance is obtained.And a symmetrical L-shaped slit is introduced into the antenna structure to achieve impedance matching.The antenna works at 924 MHz on the metal surface with a gain of-8.52 d Bi,has positive semi-omnidirectional radiation characteristics,which meets the design requirements,and experimentally proves the antenna’s anti-metal performance,but this performance is easily affected by the metal edge effect.(3)To address the problem that the performance of the tag antenna is affected by the metal edge effect in the previous part,the transmission line model of capacitively coupled-fed and directly-fed microstrip antenna is compared and analysed,and the conclusion that the capacitively coupled-fed structure can effectively reduce the influence of the environment on the impedance of the tag antenna is drawn.The structure of the conventional capacitively coupled microstrip antenna is optimised by combining the virtual ground characteristics of the central part of the microstrip antenna radiating sheet,while introducing matched open lines and rectangular slits to eliminate the short circuit structure of the microstrip antenna,making the antenna have a planar structure and good adaptability to the metallic environment.The antenna operates at 922 MHz with a gain of-4.36 d Bi on a metallic surface,and it has been verified through experiments that the antenna can still maintain good performance when used on metallic planes of different sizes.