Theoretical and numerical study of a novel mode-localized accelerometer using coupling-stiffness perturbation

Conventional Micro-Electro-Mechanical Systems (MEMS) mode-localized sensors based on mass or stiffness perturbation are constrained by a fundamental sensitivity limit due to mode aliasing. To overcome this challenge, this paper proposes a novel coupling-stiffness-perturbed mode-localized accelerometer (CSP-MLA). The sensor transduces external acceleration into variations in the coupling stiffness of a weakly coupled resonant system, enabling highly sensitive detection. A new readout scheme based on the reciprocal of the differential reciprocal amplitude ratio is introduced. Theoretical analysis confirms that the proposed approach can surpass the sensitivity limit inherent in traditional mode-localized sensors. The device performance is evaluated via finite-element simulations. The optimized structure exhibits a first-order modal frequency of 128.96 Hz and achieves an acceleration-to-displacement sensitivity of 1.55 × 10−4 m/g and a mechanical sensitivity of −0.152 61/g (387 493 ppm/g). Simulation results validate the effectiveness of the proposed CSP-MLA design, offering a promising pathway for developing high-performance MEMS accelerometers.