The Development Of Dual-axis Vibration Sensor

In this thesis, we focus on dual axis capacitance vibration transducer, which was fabricated by Micro-electromechanical Systems (MEMS). The operation mechanism of this kind of accelerometer was analyzed. Under external acceleration, the space between sensitive quality mass and detecting electrode will change, which causes the variation of equivalent capacitance. This can be detected by the accelerometer to obtain the acceleration. The vibration transducer has many advantages such as simple processing, low temperature coefficient and high stability. This thesis consists of two parts as follows:Firstly, after the analysis of the mechanism of differential capacitive accelerometer, the structure design and analysis of the sensitive chip were presented. In order to make the sensitivity of 2-demension accelerometer along the two main arbors almost identical, symmetric four-beam structure that embeds a double-sides interdigitated differential capacitive with puckered beam in two directions was used as sensitive component. In addition, the differential capacitive accelerometer fabricated by bulky silicon micromechanical technique has high sensitivity, wide measurement scope, less nonlinear error, and simple converting circuit. Then, the structure parameters of the sensitive component were calculated and stimulated, which results in a set of the optimized structure design parameters, main fabrication procedure and several key fabrication technology. Furthermore, capacitance-voltage converting circuit in the sensitive chip was designed and analyzed, and using differ-measurement technique trivial capacitance variation caused by vibration could be converted into detective voltage signal.Secondly, signal processing circuit was designed and simulated. Utilizing the design of external shell, dual axis capacitive accelerometer was succeeded, and the sensitive properties were characterized and analyzed. With the assistance of signal processing circuit consisted of amplifier circuit and filter circuit, the signal from the sensitive chip is converted into the voltage signal that meets the product performance requirement. Moreover, we employed micromechanical technique to fabricate the...