Design, Fabrication, and Performance Characterization of LTCC-Based Capacitive Accelerometers.

Area of Science:

• Materials Science
• Electrical Engineering
• Mechanical Engineering

Background:

• Capacitive accelerometers are crucial for motion sensing.
• Low-temperature co-fired ceramic (LTCC) technology offers advantages for fabricating integrated sensors.
• Conventional LTCC processes face challenges in creating complex microstructures like those needed for accelerometers.

Purpose of the Study:

• To develop and characterize two distinct capacitive accelerometer designs using LTCC technology.
• To overcome fabrication challenges associated with complex LTCC microstructures.
• To evaluate the performance of LTCC-based accelerometers for potential applications in demanding environments.

Main Methods:

• Fabrication of a key structure with a heavy proof mass and thin beams within a large cavity using an optimized LTCC process.
• Development of an LC resonant accelerometer employing coupling resonance frequency sensing.
• Development of a differential capacitive accelerometer utilizing differential capacitive sensing.

Main Results:

• The LC resonant accelerometer achieved a sensitivity of 375 KHz/g over a 1 g range with <6% nonlinearity and 5 mm telemetry distance.
• This LC resonant sensing technique is novel for LTCC accelerometers and shows promise for harsh environments.
• The differential capacitive accelerometer demonstrated a larger full-scale range of 10 g with <1% nonlinearity and a sensitivity of 30.27 mV/g.

Conclusions:

• Optimized LTCC processing enables the fabrication of complex accelerometer structures.
• Two distinct LTCC capacitive accelerometer designs offer different performance characteristics suitable for various applications.
• The developed accelerometers, particularly the LC resonant type, show potential for use in harsh environments.