Research And Development Of Passive Strain Sensor Based On RFID System

In the field of civil engineering health monitoring,strain monitoring is always one of the most important monitoring objectives.In order to realize strain monitoring more effectively and conveniently,lots of experts in the field of civil engineering health monitoring have developed various strain sensors.However,none of the strain sensors used at present can achieve passive contactless reading,which not only brings huge monitoring cost to engineering application,but also brings inconvenience to long-term and stable monitoring.In recent years,with the rapid development of passive RFID technology,it can quickly realize passive non-contact reading of tags,which has been widely developed and applied in the field of Internet of Things.RFID tag is composed of chip and antenna,and the antenna has special mechanical characteristics-its resonance frequency has a good linear relationship with the physical size of the antenna.Inspired by this fact,the tag antenna can be designed as a rectangular patch,which is convenient for strain measurement.In this paper,a new strain sensor is designed and optimized with passive RFID technology,and the new strain sensor is fully verified and discussed from the aspects of theory,simulation and experiment.Firstly,this paper introduces the RFID technology,and the technical operation principle of using this technology to achieve strain measurement,and then proves the feasibility of using this method to achieve strain measurement from the theoretical level.Secondly,through the excellent selection of label materials and the integration and optimization of a variety of indicators,we designed a new type of sensor independently.The communication distance of the new sensor has been improved greatly.Compared with previous scholars,the performance of the label in all aspects has been also greatly improved.The strain measurement performance of the sensor is simulated in COMSOL.In addition,the difference between the theoretical values and simulation results of resonance frequency is analyzed.Then the maximum readable distance of the sensor and the readable range in space of the sensor are verified from the experimental point of view,and a simple readable range diagram is drawn.Secondly,the actual effect of strain measurement of the sensor is explored through strain tensile test,the reasons for the difference between simulation results and test results are compared,and the strain transfer-rate of the sensor is analyzed through further theoretical derivation and test.Finally,through comprehensive theoretical analysis and experimental results,the sensor adopted the method of paste for practical application of paste,it has a variety of disadvantages.This paper proposed a new way to measure cable force,which is composed of the sensor and the anchorage.In addition,the algorithm of multi-sensors reading is also studied.