Structural Design and Simulation Analysis of a Sin-gle Proof Mass Triaxial Capacitive Accelerometer Based on Dual Staggered Seesaws

Weiwei Cao, jianqiang han, Ge Shi, Shilong Zhao, Jiarui Liu

Abstract


Driven by the demand for high-sensitivity, low-noise, low-power capacitive accelerometers in geological hazard detection, vibration monitoring and other application scenarios, this paper presents a novel triaxial capacitive accelerometer. Four equal-height comb capacitors with unequal gaps are symmetrically arranged around the proof mass to sense the in-plane X- and Y-axis acceleration. Two staggered seesaw structures are integrated into the proof mass. Four comb capacitors of uneven height with identical gaps are arranged at each end of every seesaw to detect Z-axis acceleration. Its fabrication process is compatible with that of in-plane comb capacitors, eliminating the temperature sensitivity and fabrication complexity inherent in conventional sidewall capacitors. Theoretical calculations and finite element simulations show that the relative capacitance change (ΔC/C0) reaches 15.8% for in-plane motion and 9.0% for out-of-plane motion under 2 g acceleration, while cross-axis sensitivity is less than 3%. The theoretical Brownian noise densities are 1.37 μg/√Hz for the X- and Y-axes, and 1.82 μg/√Hz for Z-axis. These results demonstrate that the proposed accelerometer enables simultaneous detection of in-plane and out-of-plane accelerations with high sensitivity and low cross-axis interference.

Keywords


MEMS; triaxial capacitive accelerometer; dual staggered seesaws; comb capacitors

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References


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DOI: https://doi.org/10.33180/InfMIDEM2026.203

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