A microwave SIW sensor loaded with CSRR for wireless pressure detection in high-temperature environments

In this study, a microwave substrate integrated waveguide (SIW) sensor loaded with complementary split ring resonator (CSRR) for wireless pressure detection in high-temperature environments was presented. The CSRR structure is placed directly above a substrate with an embedded sealed cavity, which is sensitive to pressure. The resonant frequency of sensor is in response to pressure because the strongest electromagnetic field is mainly concentrated on the CSRR. The working principle of the pressure sensor is elaborated via circuit analysis and simulation optimization of high frequency structure simulator (HFSS). The designed sensor worked at about 2.4 GHz to avoid use of expensive measurement equipment. The sensor was customized, and fabricated on the high temperature co-fired ceramics (HTCC) using the three-dimensional co-firing and screen printing technology. The as-prepared sensor can stably work at the ambient environment of 25 °C–800 °C, and 10–300 kPa with a highest pressure sensitivity of 206.89 kHz kPa−1 at 800 °C. The sensor described in this study has the advantages of simple structure, higher quality and sensitivity, and lower environmental interference and has the potential for utilization in multi-site pressure testing or multi-parameter testing (temperature, pressure, gas) in high-temperature environments.