Improving the Performance of MEMS Resonant Sensors with Synchronized Piezoresistive/Capacitive Transductions using Signal Fusion

This paper presents a novel MEMS resonant sensor simultaneously employing piezoresistive and capacitive transductions to generate high-correlation intrinsic noise and signal outputs. The design enables significant flicker noise reduction with a generic recursive filter. The sensor features a double tuning-ending fork resonator with dual piezoresistive gauges that transduces the signals synchronously via both piezoresistive and capacitive mechanisms. The synchronized signals extracted from the two transduction mechanisms are fused with a Kalman filter implemented in a FPGA. The experimental results demonstrate a frequency bias instability of 1.9 ppb with the application of signal fusion, which is a 20-fold improvement compared to using capacitive transduction alone.