Chipless RFID Label Design

In recent years,Radio Frequency Identification(RFID)technology has developed rapidly and has been widely used in industrial automation,commerce,transportation management and other fields.Compared with RFID technology with chips,chipless RFID tags have the advantages of miniaturization and low cost.This thesis studies the design of chipless RFID tags.Firstly,a chipless RFID tag based on Split Ring Resonator(SRR)is designed.The relationship between the size of SRR structure and the corresponding resonance points is analyzed,and the influence of coupling between resonator units on resonance frequency is also analyzed.Secondly,aiming at the shortcomings of the first SRR-based chipless RFID tag,which has a large mutual coupling effect and a low bandwidth utilization,an improved SRR chipless tag is proposed.The resonant notch depth varies with the coupling distance between the resonator unit and the microstrip transmission line,which enables the resonator unit to achieve 2 bits coding capacity.The measured results of the tag are basically in agreement with the simulation results.The tag achieves 12 bits coding capacity during the frequency band 4.5GHz~6GHz.Finally,a chipless RFID tag based on the Complementary Split Ring Resonator(CSRR)is proposed.The proposed tag reduces the coupling effect between resonator units and achieves a high code density.Between 4GHz and 8GHz,the coding density of the tag is as high as 2.5 bit/cm.At the same time,the resonator unit has fewer sensitive parameters,which reduces the complexity of the optimization.