Reserach Of Electromechanical Integrated Micro Resonator Gas Sensor

Micro resonant gas sensor is referred to as one of transforming gas into a measurable electrical signal device.Micro resonant gas sensor has advantages such as high sensitivity,good selectivity and repeativity.The smaller resonant gas sensor's physical size is,the higher the sensitivity is.However,the application of resonance gas sensor is restricted by a lot because of the influence of the conditions of the work process and testing technology.This paper puts forward a new type of electromechanical resonant gas sensor,whose sensitivity is increased by adding the 180 degree feedback on the micro beam sensors.This paper have analyzed instantaneous frequency and sensitivity of the integrated micro beam,and taken a closed loop test of the integrated micro beam sensor.In this paper,the mechanical,chemical and molecular force coupled dynamics model of micro resonator gas sensor is established firstly.The expression of instantaneous and natural frequency is deduced,and micro and nano cantilever beam vibration characteristics of resonant sensor is studied.Then,the electromechanical micro resonator gas sensor's vibration model is established.The expression of electromechanical micro resonator gas sensor's instantaneous frequency and sensitivity is deduced.The vibration characteristics of nano beam sensors,micro beam and integrated micro beam are analysed.Under the condition of external thermal excitation,double beam dynamics model is established,and the expression of instantaneous and natural frequency is deduced.The instantaneous frequency and sensitivity of nano beam sensors and integrated micro beam under the condition of different molecular force are analysed.At last,reasonable microcantilever beam production scheme using MEMS processing technology processing of high precision harmonic components is designed on the basis of the existing experimental conditions.A 180-degree feedback control module on the original test system is designed,and a integrated resonant sensor's frequency sweep test and a closed loop 180-degree feedback experiment are done.Experimental results showthat the mechanical and electrical integrated sensor sensitivity has been improved obviously,the feasibility of using 180 degrees closed-loop feedback to improve sensor's sensitivity is verified.