The frequency characteristics of the beam resonator of the thermal excited silicon resonant pressure sensor

The frequency characteristics of the beam resonator of a thermal excited silicon resonant pressure sensor are investigated in this paper. The sensing component of the silicon resonant pressure sensor is the silicon bossed structure, whose preliminary sensing unit is a square silicon diaphragm, the final sensing unit is a silicon beam resonator. The exciting unit is a thermal resistor and the detecting unit is a piezo-resistor. The operating mechanism is analyzed based on the actual sensing structure and the exciting and detecting means of the silicon sensor. The constant temperature profile of the beam resonator and the corresponding thermal feature of the silicon sensor, caused by the thermal exciting resistor and detecting resistor are presented. The relationship between the natural frequency of the beam resonator and the measured pressure applied to the square diaphragm is established. The stability condition of operation is presented for the above silicon sensor. And some principles to determine geometric parameters of the resonant beam, locations on the beam resonator and parameters of the thermal exciting resistor and the detecting piezo-resistor are provided in this paper.