Microwave Scattering Wireless Temperature/Pressure High Temperature Sensor Based On SIW Resonator

The wireless temperature and pressure sensors that can be used in high temperature environments have a wide range of needs in the fields of aviation,aerospace,defense and military,etc.,especially for the monitoring of key parameters in harsh environment of the engine,which has great research significance.However,the current wireless sensors cannot meet these test requirements due to their dimensions or performance limitations at high temperature.In response to the above problems,this paper proposes some wireless passive sensing structures based on substrate integrated waveguide?SIW?resonator.Through the performance test of the sensor substrate materials,the simulation optization of the structure size and the exploration of the preparation process.Finally,the high-temperatrue pressure and temperature sensors with high quality factor,small size,and strong anti-metal interference capability were prepared respectively.The research work of this paper can be summarized as follows:1.The structure composition of the substrate integrated waveguide?SIW?is studied,the equivalent correspondence between the SIW structure and the rectangular waveguide are established,the electromagnetic propagation characteristics in SIW are analyzed,the calculation formula of SIW propagation characterstic parameters is deduced,and finally the frequency calculation formula of common substrate integrated waveguide resonstors are deduced.2.By analyzing the working principle of the high temperature sensors based on the substrate integrated waveguide structure,then determine the critical parameters of the substrate material that affect the response of the sensor.Three kinds of ceramics,99Al₂O₃,97Al₂O₃ and sapphire,are selected as the research object,the coefficient of thermal expansion and thermal strain are measured by the graphite differential method,the bending strength and bending elastic modulus of the ceramic are tested by the three-point bending method.Finally,the base material for preparing the high temperature sensors based on the SIW structure is determined.3.A resonant temperature sensor based on SIW structure is designed,the sensor signal can be read wirelessly by integrating the slot antenna on the SIW structure.Then the effects of substrate thickness on resonator performance and the effect of slot antenna size on coupling effect are studied respectively by the HFSS?High Frequency Structure Simulator?;the temperature sensor are prepared by the laser cutting and screen printing techniques;a coplanar waveguide antenna made of platinum and alumina ceramics were used to feed the sensor wirelessly;the high temperature frequency response of the sensor was tested at a different distance respectively,and the sensor was repeatedly tested at 30°C to 1200°C four times.4.A high-temperature pressure sensor based on SIW is proposed.The initial size is calculated according to the center frequency,and the final size of the slot antenna is determined by software simulation.The pressure sensor is processed by the HTCC micro-assembly process,where a carbon film was used to as a sacrificial layer to form the cavity.Finally,a metal waveguide was used as the feed antenna;the frequency response of the sensor at different temperatures was tested in a high temperature and pressure composite test platform.