| Aeroengines and heavy-duty gas turbines with high efficiency and high power output have a very wide range of requirements.The closed pipelines for transporting natural gas and the non-contact inspection of leaking gas are also of great significance.Existing wireless sensors cannot accurately and quickly monitor high temperature components or leaked gases in real time due to size parameter limitations,performance limitations at high temperatures,and sensitivity limitations,and there is a problem that measurement accuracy is insufficient.In order to solve the above problems,this thesis explores the possibility of applying the open-loop resonator metamaterial structure to wireless passive sensing.The high-frequency electromagnetic simulation software HFSS is used to optimize the size of the designed sensor and electromagnetically Characteristic simulation analysis and research on the preparation process of the sensor.Combined with the principle of microwave scattering sensing,it can find possible solutions for the development of in-situ test in high temperature harsh environment and closed air chamber.This paper first introduces the basic structure of metamaterials,namely the Split Ring Resonator(SRR),and designs the planar split ring resonator and nested split ring resonator(Nested-SRR)using electromagnetic simulation software HFSS.The structure is analyzed for the electromagnetic propagation characteristics of the above structure in an electromagnetic field.The effects of substrate material and dielectric load on the electromagnetic properties of the structure were investigated.Combined with the sensing principle and advantages of the microwave scattering sensor,the open-loop resonator is applied to the wireless passive sensor,and the sensing principle and test method are explored.A planar thin film type wireless passive high temperature sensor based on SRR is designed.The HFSS electromagnetic simulation software is used to complete the size design of the SRR structure,the design of the sensor substrate thickness,and the electromagnetic field distribution of the sensor.The high temperature co-fired ceramic technology is utilized.Sensors are prepared by screen printing technology;three interrogation methods for coplanar waveguide antennas,metal waveguides and monopole antennas as interrogation antennas are studied;sensors made for multiple SRR structures of different sizes are studied and It is applied to chipless radio frequency identification(RFID).The antenna selected in the experiment is a coplanar waveguide patch antenna.The best interrogation distance of the antenna to the sensor is selected by the distance test experiment,and the distance is applied to the high-temperature test of the subsequent sensor to ensure that the network analyzer collects strong data.The hightemperature test platform was built to complete the high-temperature test of the sensor.The test temperature ranged from 28℃ to 1100℃.The test data was analyzed and the sensor was repeatedly tested to ensure the sensor has good repeatability.A thin-film wireless passive gas sensor based on Nested-SRR is researched and proposed.The HFSS electromagnetic simulation software was used to study the electric field and the electromagnetic field distribution of the sensor in the metal resonant ring.The new nanocomposite of silver modified molybdenum disulfide was selected as the gas sensitive material.The sensitive mechanism of the nanocomposite on ammonia was studied.The magnetron sputtering method is used to prepare the sensor,build a gas test platform,and complete the performance test of the gas sensor by changing the concentration of the ammonia gas. |
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