Research On Wireless Energy Transmission And Identification Of Tags

Radio frequency identification will be another technical tide after Internet and mobilecommunications, and impact on people’s production and lives in many aspects. Thetechnology can exchange or collect information by contactless interactive way. It canrecognize multiple targets automatically and simultaneously, and monitor the targets in realtime. Radio frequency identification is an important and new direction in electromagnetictechnology field, at the same time it is also one of key technologies of the Internet of Thingswhich has been treated as an economic growth point in the next era. The technology has madea considerable development in Europe and the United States, but just start in our country.How to grasp the mainstream technology in this tide is important for the development of ourcountry’s science and technology.Two key issues are involved in the radio frequency identification technology, that arepower transfer problem and identification problem of tags. For the former, wireless energytransmission is an important way, but the shortcoming of short transmission distance limits itsapplication. For the latter, the problem of inefficient identification resulted by tags’ collision isa key issue. Therefore, the research focus on wireless energy transmission and identificationof passive tags, and the specific contents are as follows:(1) In order to solve the problems of short transmission distance and inefficient… in theprocess of tag’s wireless energy transmission, a new strong magnetic coupling resonanceenergy transmission method with farther distance and higher efficiency was proposed. Thebasic resonance circuit was improved by adding resonance coils. Two models based on seriesresonance circuit and parallel resonance circuit were given. And moreover, the correspondingequipments based on new models were designed and built. Experimental results show that themaximum transmission distance under the two new methods is three size of that one under thebasic resonance, and the transmission efficiency of series resonance is four size of that oneunder the basic resonance. Moreover, the transmission efficiency of parallel resonance hasbeen also improved obviously.(2) In order to conquer the shortcomings of general binary anti-collision algorithms, such as more interaction times and communication data, an algorithm of conversely searching wasproposed. By the identification tree which is constructed by the reversely searching method,the leaf nodes can be identified on the father level, which decreases the interaction times. Nomatter whether the tags’ collision bits are consecutive or not, the algorithm is always effective.On interaction times and communication data, the new algorithm has obvious superiority,especially when there are many tags within the scope of reader and collision bits are less thanthe length of tags.(3) In order to solve the problem of existing redundant information in communicationdata during indentifying multiple tags, based on multi-state binary anti-collision algorithmand backtracking binary searching algorithm, a multi-state binary algorithm with informationpreprocessing was proposed. The information preprocessing mechanism makes the algorithmonly need to deal with collision bits. The partly received mechanism makes the reader onlyneed to receive available data. Thus, the problem of sending and receiving data repeatedly canbe avoided, and the communication data are reduced greatly. Simulation results show that thenew algorithm has obvious advantage in reducing the communication data when the collisionbits are not continuous, and collision rate is lower than20%. Excluding the informationpreprocessing, the new algorithm has more significant advantage at any collision rate.(4) Considering the availability and safety during the communication process ofidentifying tags, FPGA was introduced into the communication process. The hardwaredesigns corresponding to reversely searching binary algorithm and multi-states binaryalgorithm based on information processing were given separately. The hardware system of thecommunication process between reader and tags based on FPGA was also designed andrealized. The experimental results show that the system has lower resource consumption,higher data communication speed, and its hardware acceleration ratio is up to4.7and1.5.