Research On Design Of UHF RFID Tag Binding With Material Electromagnetic Property

As the rapid development of internet of things(IoT)technology,information security problem of radio frequency identification(RFID)is attracting more and more attention.Since the simple structure the RFID tag has,more safety concern should be put into tag security protection accordingly.Generally,an RFID tag security could be guaranteed through three mechanisms:1.Physical anti-imitaiton security mechanism;2.Data encryption security mechanism;3.Special circuit security mechanism.Such efforts have greatly strengthened the data security of RFID systems.However,the security mechanism mentioned can not solve the mismatching problems between the real items and information recorded in RFID chip.Once tags are attaching to some wrong items,RFID data may be misapplied and the information security system built for RFID system will collapse from the root.Therefore,RFID tags bonding together with specified objects should be another cornerstone of RFID information security.This dissertation is mainly focused on secure RFID tag designing which could bind with material electromagnetic property.If a RFID tag antenna is designed to react strongly to small change of electromagnetic properties of object dielectric,the tag can be viewed as bond to the object,because misuse of such a tag will dramatically degrade its operation.The mainly research contents consisted of five parts which listed as follows:1.Foundamental theory of material sensing antenna design.Take an investigate on relationship between varies of electromagnetic properties and radiation properties of an horizon dipole.Give a brief introduction of relationship between input impedance properties and antennas structures with respect to several different types of antennas and last draw a conclusion of that it is very important of antenna structure chosen in material binding antenna design.2.Design of RFID tag binding with material electromagnetic property.Binding index is proposed to judge binding property between material and RFID tag.By means of analysis of triangle index and power transmission coefficient between tag antenna and chip,a regulation which input impedance of tag antenna should obey is illustrated.In permittivity sensitive tag design,analysis of correlativity between effective permittivity and antenna structure is given,key property of meander-line antenna which suit for designing a permittivity sensitive tag is provided,two useable tags is also provided.In conductivity detective tag design,by using of model of lossy resonator,design method of such a tag is given.Based of the method,two tags with inverted F structure are proposed where one for low conductivity detection and the other for high conductivity detection.In metal friendly tag design,a monopole antenna structure with a archimedian radiation part is taken into consideration,a tag with sensing ability to metal nearby is presented.3.Design of RFID tag with improved binding property dedicate to electromagnetic property varies.Based on fragment-type structure,along with using of multi-objective optimization algorithm,this part provide a method of designing a high performance material binding tag antenna.Three related tags are designed by using the presente method,which consisted of a tag which has a higher binding property to permittivity change,a tag with a more stable performance when conductivity of liquid stays at stable area,and a tag has a more sensitivity property to metallic object.Besides,some design tactics are also illustrated in details,such as hybrid design tactics consisted of discrete variables and continuous variables.4.Research on design of material sensor.Present a concept of passive material sensor and provide a method of designing such a sensor.When a common used RFID tag equipped with such a sensor,the tag will become sensitive to a special dielectric.The design method is deduced by using of Q value equation and relationship between Q value and impedance of antennas.Four related material sensors are provided.5.Measurement of designed material binding RFID tag.Based on analysing of equivelant permittivity of dual-layer slab system,a creterion of items packaging method is provided,in addition,method of tag substrate chosen is presented.According to the analysis,a structure which could be equivelant to a material with arbitrary permittivity is proposed,by means of such a structure,tags which proposed in the previous chapters are tested.The testing results agree well with the simulated results.This dissertation provide a research on design of RFID tag binding with material electromagnetic property by using of theory of antenna radiation field analysis,impedance expression analysis of a equivelant circuit with respect to several common used antenna,relative pemittivity analysis,lossy resonator analysis and Q value deducing of electrical small antenna.Four material binding tags are provided.Besides,by means of using multi-objective optimization algorithm and fragment-type structure,three material binding tags with high perfomance are also provided.Based on the designed sensor tags,concept of passive material sensor is presented by calculating Q value of the antenna.The design method is fully proved by two material sensor designs.In addition,analysis of equivalent permittivity of dual dielectric slab which dedicate to use in items packaging and measurement system building is provided.Last,an articulated measurement of the designed tags is provided,the results have a good agreement with simulated results.