A Micromachined Capacitive Pressure Sensor Using a Cavity-Less Structure with Bulk-Metal/Elastomer Layers and Its...

Area of Science:

• Microelectromechanical Systems (MEMS)
• Sensor Technology
• Materials Science

Background:

• Micromachined capacitive pressure sensors often face challenges with vacuum cavities and lead transfer.
• Mechanical robustness is critical for many pressure sensing applications.
• Existing designs may not be suitable for harsh or submerged environments.

Purpose of the Study:

• To develop a mechanically robust micromachined capacitive pressure sensor.
• To enable wireless interrogation of pressure measurements.
• To evaluate the sensor's performance and temperature dependence.

Main Methods:

• Fabrication of stainless steel plates using micro-electro-discharge machining.
• Integration of a 38-μm polyurethane layer as the deformable element.
• Construction of passive inductor-capacitor (LC) tanks for frequency-based interrogation.
• Demonstration of wireless sensing in liquid via magnetic coupling.

Main Results:

• Achieved a sensitivity of 23-33 ppm/KPa over a 340 KPa dynamic range.
• Experimental results align with theoretical estimations.
• Successfully demonstrated wireless pressure sensing in a liquid medium.
• Evaluated the temperature dependence of the LC tank.

Conclusions:

• The developed sensor offers a robust and reliable solution for pressure measurement.
• The wireless interrogation capability simplifies deployment and data acquisition.
• The design eliminates common challenges associated with traditional micromachined capacitive sensors.