Full-scale linear sensing of mode-localized sensors enabled by optimized readout circuit

This paper proposes a novel single-port readout circuit to realize the full-scale linear sensing of mode-localized sensors. In our proposal, in addition to the conventional frequency closed-loop control, the amplitude closed-loop based on automatic gain control (AGC) is adopted to stabilize the amplitude product of resonant units at a normalized value so that the difference of squared amplitudes can be regarded as the sensor readout to characterize the variations of external input signals. A micro-electro-mechanical system (MEMS) mode-localized accelerometer prototype is tested based on our proposed readout circuit. The experiment results demonstrate that the tested accelerometer prototype realizes the linear sensing in the full measurement range and shows a mechanical sensitivity of 0.1182 /g with a maximum non-linearity of -6.54 %, which are basically consistent with the output metric based on the subtraction of reciprocal amplitude ratios (SRAR).