The Design of Temperature and Pressure Composite Sensor and the Nonlinear Decoupling Research of Two Parameters

In response to the demand for real-time monitoring of temperature and pressure in harsh environments, a microwave substrate-integrated waveguide (SIW) temperature–pressure composite sensor loaded with complementary split resonant ring (CSRR) structure is proposed in this study for real-time testing of temperature and pressure dual parameters in a high-temperature environment. Based on the sensitive texture of the dielectric constant of the alumina ceramic material to temperature and the sensitive mechanism of the sealed cavity film to pressure, the relationships between the resonance frequency of the sensor and the ambient temperature and the resonance frequency and the pressure were established, respectively. The prepared sensor was tested in high-temperature and high-pressure environments, which showed that the sensor can work stably in 25 °C–1200 °C and 0–700-kPa environments. Furthermore, the nonlinear decoupling model of temperature–pressure two parameters is proposed, and the simultaneous acquisition of temperature-pressure two parameters is successfully realized. The sensor has the advantages of simple structure, small size, high sensitivity, and small environmental interference and has the potential to be applied to multiparameter (temperature, pressure, and other parameters) test in high-temperature environment.