Smaller smarter sensor delivers precision vacuum measurement across vast pressure range

Smaller smarter sensor delivers precision vacuum measurement across vast pressure range
by Riko Seibo
Tokyo, Japan (SPX) Jun 17, 2025

A new MEMS-based vacuum sensor developed by researchers at the Aerospace Information Research Institute of the Chinese Academy of Sciences promises to redefine pressure monitoring in critical environments. Utilizing a dual-mode weak-coupling resonator (WCR), the sensor adapts between high-sensitivity and stable-accuracy modes, achieving reliable measurements from 0.3 to 100,000 Pa.

This innovation addresses long-standing limitations of conventional sensors. While Pirani gauges offer range, they lack accuracy and gas-independence. Capacitance diaphragm gauges (CDGs) provide precision but only within narrow spans. Hybrid systems tend to be bulky, and mode-localized sensors often sacrifice consistency across ranges. The new device overcomes these hurdles by uniting mode-localization with traditional resonance on a single compact chip.

Published May 21, 2025 in Microsystems and Nanoengineering, the study describes how the sensor automatically shifts between modes depending on pressure. Below 1,000 Pa, it uses mode-localized detection-sensing stiffness shifts via amplitude ratio changes with a sensitivity of 30,000 ppm/Pa and resolution of 0.1 Pa. Above this threshold, it switches to traditional resonance mode, measuring output frequency with 2 Pa resolution and high linearity.

At the heart of the sensor is a MEMS-fabricated two-degree-of-freedom WCR built on a deformable diaphragm and two H-type double-ended tuning fork resonators. This differential design minimizes noise and stress while maintaining compactness. Encased in a vacuum-sealed cavity, the entire chip occupies just 27.2 mm-far smaller than commercial counterparts. Tests across temperatures from -20 oC to 120 oC confirmed excellent stability, minimal drift, and low hysteresis.

"By combining two sensing principles within a single MEMS platform, we've created a device that's compact, precise, and scalable," said lead author Prof. Junbo Wang. "This dual-mode operation gives it a level of versatility that current vacuum sensors simply can't match."

The device's broad-range capability and independence from gas type reduce calibration demands, allowing seamless integration into semiconductor manufacturing, space probes, and other high-demand applications. Its performance and scalability suggest it could become a standard for real-time vacuum sensing in next-generation technologies.

Research Report:A novel high-performance wide-range vacuum sensor based on a weak-coupling resonator