An accurate dew point sensor based on MEMS piezoelectric resonator and piecewise fitting method

Dew point sensors are widely used in various fields to provide accurate data of absolute humidity. In this paper, the dew point sensors based on MEMS piezoelectric circular resonator and cantilever are designed and fabricated. The previously reported MEMS dew point sensors suffer unavoidable errors by regarding dew point as the temperature corresponding to the maximum resonant frequency during cooling. Here, a piecewise function fitting dew point identification method is proposed, which considers the influence of relative humidity on resonant frequency and can detect dew point with small error. The results show that the piezoelectric resonant dew point sensor has good accuracy and stability, and the maximum relative error of the dew point is 0.30 degrees C DP. The proposed dew point sensors and method for identifying dew point have great potential in practices.