A Laterally Driven Micromachined Resonant Pressure Sensor

MEMS oscillating squeeze-film pressure sensor with optoelectronic feedback

“…f res (5) where σ f (τ) is the standard deviation determined from many frequency measurements each having an averaging time τ. σ ω = 2π σ f can be determined from the oscillator's phase noise spectrum S ϕ [26]:…”

“…Most conventional sensors determine pressure by capacitive or piezoresistive measurement of the static deflection of a suspended membrane caused by a difference between the ambient pressure and the pressure in a reference cavity [4]. In addition to these static sensors, several dynamic or resonant pressure sensors have been reported that detect a stress induced change in resonance frequency [5][6][7]. The fabrication of all these devices is however complicated by the need for a sealed reference cavity.…”

Micromachined pressure sensors: review and recent developments

“…A new class of pressure sensor has been reported in recent years: the resonant beam pressure sensor. These sensors operate by monitoring the resonant frequency of an embedded doubly clamped bridge [56][57][58] or comb drive [59], as shown schematically in figure 8. The resonant beam, which has also been called a resonating beam force transducer [60], acts as a sensitive strain gauge [61].…”

“…One method is electrostatic excitation and piezoresistive sensing: the structure is driven to resonance by AC applied voltages, and the resonant frequency is measured by piezoresistors [56,57]. Structures can also be optically excited by laser and sensed by a photodetector [58], or electrostatically excited and capacitively sensed [59]. Resonant pressure sensors have been shown to exhibit better pressure sensitivity and lower temperature sensitivity than pure piezoresistive sensors.…”