The Design Of CSRR-SIW Wireless Passive High Temperature Sensor And Circuit Measurement System

Aiming at the requirement of real-time monitoring for the main components of aero-engine,heavy gas turbine,rocket engine and other power equipment in harsh environments such as high spinning,high pressure,high temperature and dynamic environment,a wireless passive sensor and its back-end measurement system circuit that can measure real-time temperature in ultra-high temperature environment are proposed.Wireless passive high temperature sensing system based on microwave scattering principle includes two parts:high temperature sensor and inquiry antenna.The designed high temperature sensor adopts substrate integrated waveguide（SIW）and complementary open resonant ring（CSRR）structure,which belongs to the resonant cavity sensor.The resonant cavity is filled with high temperature resistant ceramic dielectric materials.The design of CSRR structure combined with SIW resonator reduces the structure size of high temperature sensor,improves the quality factor（Q）of high temperature sensor and anti-interference ability to metal environment.The high-temperature sensor coupled the sweep signal emitted by the interrogation antenna to the SIW resonant cavity through the CSRR structure.The signal at the resonant frequency of the sensor formed a standing wave in the resonant cavity,and its reverberation signal was reflected back to the interrogation antenna.The resonant frequency of the sensor is analyzed by inquiring the echo signal reflected by the antenna.The dielectric constant of the dielectric substrate will fluctuate due to the change of the external environment temperature,and the resonant frequency of the sensor will also change.Therefore,the functional relationship between temperature and resonant frequency can be established.The high temperature sensors designed in this paper are CSRR-SIW high temperature sensor and improved CSRR-SIW high temperature sensor.On the basis of the traditional CSRR structure,the former improves the size of the internal and external resonant ring gaps of the CSRR structure with different sizes.Through high-temperature test,it is obtained that the temperature sensitivity of the sensor is 123 k Hz/℃ and 417 k Hz/℃ respectively within50℃-450℃ and 450℃-1000℃,which shows a linear change in different temperature ranges.Compared with the previously reported high temperature sensors,the temperature sensitivity at high temperature stage is about three times higher.The latter can significantly improve the sensitivity of the sensor under the same size by folding the external resonant ring of the CSRR structure.In the temperature range of 50℃-1000℃,the average temperature sensitivity of the improved CSRR-SIW high temperature sensor is 244.7 KHz/℃,which shows a linear change in the whole temperature range.The resonant frequency of the high temperature sensor is extracted by building a circuit measurement system.The circuit measurement system includes signal source module,transmission channel conversion module,power detection module,signal acquisition module and control module.Through high temperature test,the results show that the cost of the measurement system designed in this paper is lower and the relative error is less than 1%.The circuit measurement system provides a portable measurement technology scheme for field test.