Toward High-Resolution Inertial Sensors Employing Parametric Modulation in Coupled Micromechanical Resonators

Highly accurate microelectromechanical-systems inertial sensors have a wide range of potential applications, including inertial navigation and seismometry. Conventional approaches to the implementation of inertial sensors rely on transducers that convert the external acceleration into changes in displacement of a proof mass or shifts in resonant frequencies. Recently, it has been demonstrated that inertial forces can also be measured through the monitoring of the spatial energy distribution between two coupled microresonators. To extend this approach, we show that a weak dynamic coupling can be established through periodic modulation of the stiffness for a mechanically coupled microresonator system integrated as part of an accelerometer, enhancing the scale factor and resolution of the accelerometer. The resulting capability of parametric modulation also enables the tuning of the operating point of the accelerometer through the modulation frequency. Utilizing this technique, we show that the scale factor of the accelerometer can be enhanced by a factor of 188 and a factor-of-25 improvement in sensor resolution is demonstrated. Dynamic tuning of the sensor scale factor and inherent noise filtering are also demonstrated.