A Wide Temperature Range Mode-Localized Vacuum Gauge With Temperature Compensation

Vacuum gauges are widely used in industrial equipment. However, conventional vacuum gauges, such as capacitance diaphragm gauges, are sensitive to temperature variations. These gauges typically use a thermostatic cavity to maintain the sensing elements at a constant temperature above the ambient environment, which leads to a narrow operational temperature range, large volume, and high power consumption. Therefore, they are not suitable for aerospace applications. This study develops a temperature-compensated resonant vacuum gauge based on mode localization. The proposed sensor works by detecting diaphragm deformation generated by vacuum pressure through a weak-coupling resonator (WCR). The mode localization phenomenon of this type of resonator can enhance the sensitivity to stress compared to the traditional diaphragm-based gauges. Differential sensing of the resonator is applied to avoid excessive temperature sensitivity. Both the amplitude ratio (AR) and frequency of the coupled resonators are sensitive to vacuum pressure and temperature. Based on the two outputs of the resonator, two compensation methods are proposed, including in situ temperature compensation and thermometer-based compensation. The results demonstrate that these compensation methods can extend the temperature range from $- 20~^{\circ }$ C to 60 °C, offering a wider range than others. The accuracy is comparable to several commercial gauges.