A Comb-Based Capacitive MEMS Microphone with High Signal-to-Noise Ratio: Modeling and Noise-Level Analysis

We present a physics-based system-level model for optimizing a novel comb-based capacitive MEMS microphone towards high signal-to-noise ratios. The model includes non-linear coupling effects between the electrodes as well as the physical dependencies on relevant design parameters, thus enabling predictive statements w.r.t. the device performance. It is calibrated and validated by finite element simulations and laser Doppler vibrometer measurements of first prototypes. Being formulated as a generalized Kirchhoffian network, it can be implemented in a standard circuit simulation tool. The predicted signal-to-noise ratio of this concept reaches up to 78 dB(A), which significantly exceeds state-of-the-art devices.