A High-Precision and High-Bandwidth MEMS-Based Capacitive Accelerometer

In this paper, we present a capacitive, MEMS-based accelerometer comprising an ultra-low noise CMOS integrated readout-IC and a high-precision bulk micro machined sensing element. The resulting accelerometer reaches an acceleration equivalent noise of only 200 ng/<inline-formula> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula>Hz, which makes it suitable for seismic measurement that require noise levels significantly below 1 <inline-formula> <tex-math notation="LaTeX">$\mu \text{g}/\surd $ </tex-math></inline-formula>Hz. In addition, a high bandwidth of more than 5 kHz was achieved, which also makes the presented sensor system applicable for high-frequency measurements, e.g., in predictive maintenance applications for rotating machinery. The design of the sensing element and readout IC is presented in detail, and measurement results are shown which demonstrate the performance of the sensor system.

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