Study On Design And Fabrication Technology Of Flexible Anti-Metal RFID Sensor Tag

As the most commonly used metal material in the aerospace field,aluminum alloy,with its important structural aircraft wall plates,is susceptible to cracking during service due to the presence of stress concentration areas such as keyways and welds,which are affected by fatigue loading and corrosive environments,thus posing a potential threat to the safe operation of the aircraft.To reduce the safety risks,structural health monitoring(SHM)is needed to identify and quantitatively characterize the cracks.SHM is a technology that uses sensors to identify mechanical structures,civil and aerospace damage processes,and can be used to monitor the health of composite structures of aircraft throughout their life cycle,including development,service and maintenance.In recent years,the rapid development of Radio Frequency Identification(RFID)technology in the field of structural health monitoring has attracted a lot of attention and research from researchers.RFID technology is an,important technology in the sensing layer of the Internet of Things,which can perform automatic identification without contact.The combination of RFID technology and sensing technology,the The new sensors prepared,also known as RFID sensing tags,have the advantages of passive wireless transmission,long life and low cost,and are widely used in the fields of structural monitoring,environmental monitoring,health monitoring,fluid detection,etc.They have also become a hot study of metal crack sensing.RFID sensing tags are an effective method to achieve crack detection and monito ring of aircraft wall plates.The aircraft wall plate has a grid configuration with a grid size of 100mm×100 mm,and the weld seams are interlaced and crossed,which is prone to fatigue cracks.Accordingly,RFID sensing tags are developing towards flexibility,miniaturization and thinning,while at the same time,their sensing and communication functions are affected to some extent.Therefore,it is very important to investigate the suitable tag antenna design and processing methods to produce thinner and smaller flexible metal-resistant RFID sensing tags that are suitable for aircraft wall plate conditions under the condition of good sensing and communication functions.The main research contents and conclusions of this paper are as follows:1)Design of miniaturized and thin flexible metal-resistant RFID sensing tags.Compared with domestic and foreign sensing tags,the size is reduced to 49.2 mm×26 mm×0.85 mm.The design of short-circuit short-cut structure antenna solves the problem of difficult adjustment of antenna impedance matching with chip impedance when the tag is thinned;the design of short-circuit wall increases the surface current path of the tag,which facilitates the adjustment of tag antenna input impedance when the tag is miniaturized;at 914 MHz,the tag antenna’s Power transmission coefficient at 914 MHz is 0.9973,close to 1,S11=-13.7490 dB<-10 dB,Gain=-3.2398 dB>-6 dB,the designed tag has better impedance matching characteristics,transmission efficiency,radiation characteristics and communication function.2)Preparation of miniaturized and thin flexible metal-resistant RFID sensing tags.The piezoelectric on-demand inkjet printing customized preparation process is designed,starting from the substrate material,dielectric material and antenna ink layer,respectively.The laser treatment improves the surface free energy of the substrate material PI and improves the spreading performance of the nano-silver ink on PI;the addition of the dielectric layer enhances the bonding force between the antenna ink layer and PI and solves the problem that the antenna ink layer is difficult to adhere firmly on the smoother polymer substrate material The thinning of the antenna ink layer thickness improves the flexibility of the label,which makes the label have certain recycling effect.3)Identification and quantitative characterization of cracks of different depths and different locations of cracks in aluminum alloys.In the verification test of the practical application performance of the designed and prepared flexible metal-resistant RFID sensing tag,the maximum communication distance of the tag in a metallic environment is 0.7 m.It is able to identify and characterize the same crack location with a width of 1 mm,a depth of 0 mm-3 mm,a crack with a step of 1 mm or a crack with a width of 1 mm and different locations,which can meet the basic requirements.The miniaturized and thin flexible metal-resistant RFID sensing tag designed and prepared in this paper achieves the identification and characterization of cracks in aluminum alloy wall plates,and has some practical engineering application significance for the detection and monitoring of cracks in aircraft wall plate components.