Zhang Hemin, Pandit Milind, Sun Jiangkun, Chen Dongyang, Sobreviela Guillermo, Zhao Chun, Seshia Ashwin A
IEEE Trans Ultrason Ferroelectr Freq Control. 2021 Apr;68(4):1448-1457. doi: 10.1109/TUFFC.2020.3028567. Epub 2021 Mar 26.
Miniaturized physical transducers based on weakly coupled resonators have previously demonstrated the twin benefits of high parametric sensitivity and the first-order common-mode rejection of environmental effects. Current approaches to sensing based on coupled resonator transducers employ strong coupling where the modal overlap of the responses is avoided. This strong coupling limits the sensitivity for such mode-localized sensors that utilize an amplitude ratio (AR) output metric as opposed to tracking resonant frequency shifts. In this article, this limitation is broken through by theoretically and experimentally demonstrating the operation of the weakly coupled resonators in the weak-coupling (modal overlap) regime. Especially, a prototype microelectromechanical systems (MEMS) sensor based on this principle is employed to detect shifts in stiffness, with a stiffness bias instability of [Formula: see text]/m (9.5 ppb) and a corresponding noise floor of [Formula: see text]/m/ √ Hz (6.8 ppb/ √ Hz). The linear dynamic range of such AR readout sensors is first explored and found to be defined by the dynamic range of the secondary resonator. The proposed method provides a promising approach for high-performance resonant force and inertial sensors.
基于弱耦合谐振器的小型化物理传感器此前已展现出高参数灵敏度和对环境影响的一阶共模抑制这两个优点。当前基于耦合谐振器传感器的传感方法采用强耦合，以避免响应的模态重叠。这种强耦合限制了此类利用幅度比（AR）输出指标而非跟踪谐振频率偏移的模式定位传感器的灵敏度。在本文中，通过理论和实验证明弱耦合谐振器在弱耦合（模态重叠） regime下的运行，突破了这一限制。特别是，基于该原理的原型微机电系统（MEMS）传感器被用于检测刚度变化，其刚度偏置不稳定性为[公式：见原文]/m（9.5 ppb），相应的本底噪声为[公式：见原文]/m/√Hz（6.8 ppb/√Hz）。首次探索了此类AR读出传感器的线性动态范围，发现其由次级谐振器的动态范围定义。所提出的方法为高性能谐振力和惯性传感器提供了一种有前景的途径。
