MEMS压阻式三轴加速度传感器的双路循环电桥检测法

A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided, Finally, the test result of the ＂eight-beams/mass＂ triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.     

“钻石背”前后翼高度差对气动特性影响的数值模拟研究

在"钻石背"形翼几何外形及设计参数的基础上,选用NACA6411翼型,建立二维计算模型进行数值模拟,研究前后翼垂直高度差ΔH对低雷诺数下"钻石背"形翼气动特性的影响。结果表明,采用Transition SST湍流模型所得结果具有高的准确性和可信性;ΔH对气动特性的影响,在前后翼前缘间距约为前翼弦长的1.5倍附近,出现变化趋势反转的现象;优化气动布局的有效方法之一是合理选取ΔH和前后翼梢弦前缘间距d的设计值,在计算范围内,取ΔH=22 mm和d=100 mm,既能达到优化效果,又便于工程实际应用。     

基于C-SOI工艺的一维MEMS电容式超声传感器阵列

提出了一种新的基于C-SOI工艺制备的电容式微加工超声传感器(CMUT)的方法.通过对加工过程中一些关键工艺步骤进行测试,发现所加工的微传感器尺寸与设计尺寸基本一致,且刻蚀的空腔高度均匀,键合效果良好,证明了工艺流程的可行性.此外,通过对所加工的传感器阵列进行测试发现,各阵元谐振频率和静态电容具有良好的一致性,说明以C-SOI工艺加工的CMUT器件满足设计要求,且适宜加工大阵列,这种加工技术使得加工成像阵列成为可能.     

电容式MEMS超声传感器设计与分析

目前电容式MEMS超声传感器（CMUS）多为收发一体结构,但二种工作模式对传感器结构要求存在很大差异,设计时为了兼顾收发性能往往不能使传感器性能达到最优;此外,传统的电容式MEMS超声传感器还存在寄生电容大的缺点。针对以上问题,基于收发分离的思想,设计了一种专用作超声接收的MEMS电容式传感器,结构上采用上下电极引线互错,单元间电极联线交错的方式来减小寄生电容。通过理论分析和ANSYS仿真得到所设计传感器的最佳工作电压为586V,灵敏度为174.2fF/Pa,满足现有超声接收传感器的应用要求。