A MEMS resonant strain sensor operated in air

This paper describes a double-ended tuning fork (DETF) strain sensor that operates in resonance at atmospheric pressure. The sensor was driven with non-integrated, surface mount electronics that successfully mitigates the effects of feed-through capacitance. The MEMS strain sensor achieves a resolution of 0.1 microstrain (/spl mu//spl epsiv/) in a bandwidth of 10 Hz to 20 kHz. The measured phase noise floor at 300 Hz offset from the resonant frequency (217 kHz) is -100 dBc/Hz and the Allan variance for time intervals of 2 seconds is 0.0043 Hz. The measured strain sensitivity is 39 Hz//spl mu//spl epsiv/. These results are commensurate with current state-of-the-art sensors that are integrated with electronics and packaged in vacuum.