A Differential Split-Type Pressure Sensor for High-Temperature Applications

This study proposes a split-type pressure sensor based on differential capacitance that can be applied to in-situ accurate pressure testing in high-temperature environments. The sensor is mainly composed of a high-temperature resistant chip and a high-temperature resistant encapsulation structure. The chip is made of a ceramic substrate and presents a differential capacitance structure that can withstand high temperatures and effectively restrain the temperature drift. The encapsulation presents a split-type structure, in which the chip and the test circuit board are placed at the front and back ends of the sensor, respectively. Therefore, the front end of the sensor can work in the high-temperature area for in-situ testing, while the back-end temperature remains below 60°C all the time, which ensures normal operation of the circuit board. Finally, the test results show that the pressure sensor's temperature drift coefficient is only 6.6% within the temperature range of 25°C-400°C. The sensor's sensitivity can reach 9.27 mV/kPa and the maximum repeatability error is less than 2.2% at 400°C, which shows that the proposed sensor has a higher working temperature and higher precision than the existing pressure sensors.