Environmentally robust differential resonant accelerometer in a wafer-scale encapsulation process

This work demonstrates a unique temperature-compensated differential resonant accelerometer fabricated in a wafer-scale encapsulation process. By utilizing a pair of ultra-stable, high quality factor (>50,000) resonant beams as a strain gauge, we show differential operation with a scale factor of 427Hz/g and a bias instability of 0.16μg at 21s integration time. Furthermore, matched temperature coefficients of frequency (TCf) of the two beams provide a first order cancellation of temperature drift, resulting in a scale factor stability of 0.38% over the temperature range from −20°C to 80°C.