LC temperature-pressure sensor based on HTCC with temperature compensation algorithm for extreme 1100 °C applications

A low-profile wireless and passive sensor that simultaneously realizes temperature and pressure measurement is proposed for 1100 °C ultra-high-temperature environmental applications. The sensor, which consists of temperature-sensitive and pressure-deformable capacitors (C) and inductors (L) based on fundamental LC resonance principle, is designed and characterized. To demonstrate feasibility in a high-temperature environment, the sensor is fabricated in high-temperature co-fired ceramic (HTCC) microelectronic packing technology with Pt metallization. The results are experimentally verified with gas pressure loading in a hermetic high-temperature tank by measuring the S(1,1) parameter of the readout antenna without contact. The integrated HTCC-based sensor works normally from 70 kPa to 120 kPa in a temperature range of 20-1100 °C with a maximum pressure sensitivity of 92.98 kHz/kPa and an average temperature sensitivity of 11.33 kHz/°C. In order to precisely measure the pressure, we proposed an algorithm of temperature frequency compensation for pressure and decreased the temperature frequency excursion while measuring the pressure. Additionally, an HTCC embedded-cavity-forming method, namely a carbon film filled without an exhaust vent, is proposed and experimentally verified as valid. The sensor realizes pressure measurement with corresponding temperature in a specific environment, and thus, it is promising to realize practical engineering applications for ultra-high-temperature devices in future.