Design And Application Of Flexible Stretchable RFID Tags Based On Printed Electronic Technology

Radio frequency identification(RFID)technology is a kind of wireless communication technology,which can identify an object through RFID tags and automatically identify and read and write relevant data information.It has a huge application potential in unmanned retail,intelligent packaging and other fields.In recent years,with the development and transformation of printed electronic technology,it has been widely used in flexible circuit,Organic Light-Emitting Diode(OLED),RFID Tags,et al.Compared with traditional RFID tags,printed RFID tags have become a new research hotspot because of their low cost,high efficiency,and environmental protection.Flexible RFID tags have great applications in the field of wearable electronics.These applications require RFID tags to withstand different environmental pressure,such as repeatedly bending,folding,and even stretching,to maintain longer reading distance.The specific research contents of this dissertation are as follows:(1)A UHF RFID tag based on a half-wave dipole antenna was designed.The operating frequency is 890 MHz,the gain is 2.88 dB,and it has omnidirectional radiation characteristics to meet the design requirements.In addition,The influences of the size structure of the electric small loop antenna and the bent dipole antenna in the RFID tag antenna,the materials and the practical application environment of the tag antenna on the input impedance,resonance frequency and return loss of the tag antenna were analyzed.(2)Then we developed a stretchable conductive silver paste,with a low resistivity of 21??·cm,which is about 13.2 times higher than that of bulk silver(1.59??.cm),in low sintering temperature.The stretchable silver paste is comprised of Ag flakes,dispersant and elastomeric fluorine copolymer.The electrical properties of the conductors printed with the stretchable silver paste are significantly better than those of the two commercial silver pastes under bending and stretching conditions.(3)In the end,the stretchable conductive silver paste was printed by screen printing on cloth substrate to fabricate flexible UHF RFID tag and the performance of the tag was tested.The maximum reading distance of the flexible tag was 8.5m after bending 2000 times.And the maximum reading distance of the tag was still nearly 7 m after repeatedly stretching for 1000 times.The experimental results of the flexible RFID tags after repeated stretching in this paper are better than those reported in foreign literature.Finally,as an example of wearable electronics,the flexible UHF RFID tag was integrated into the T-shirt and the RFID tag worked normally and maintained high sensitivity and reading distance in the entire time when the tester who wore the T-shirt doing other activities.