硅岛式微谐振压力传感器灵敏度分析与仿真

微谐振式压力传感器尺寸小、重量轻、精度高并具有效字输出,在航空航天等领域有着广阔的应用前景.然而由于微机械加工工艺的限制,复杂结构的制作存在很多困难,因而为实现高灵敏度压力测量,微谐振式压力传感器的结构设计就显得尤为重要,因此提出一种新型硅岛式谐振梁支撑结构,它利用硅薄膜作为典型的一次敏感元件,并在其上表面中央部位设计了两个硅岛凸起平台,用以固定硅谐振梁,并通过有限元软件ANSYS进行仿真.分析结果表明,在一定量程内,该结构能有效提高谐振梁内的应力放大倍数,进而提高微压力传感器的灵敏度.     

扩散硅谐振式压力传感器同频干扰的建模与消除

为简化谐振式微机械压力传感器的制备工艺,提出了一种采用扩散硅作为谐振梁的压力传感器,并采用电磁激励实现传感器的闭环控制.实验中发现:由于采用扩散硅材料,传感器受到较为严重的同频干扰影响,因此,消除传感器的同频干扰成为需要解决的一个主要问题.通过对采用扩散硅作为谐振梁的压力传感器微结构进行分析,建立了传感器主要噪声来源同频干扰的等效电路模型,据此提出一种新的不对称双端激励解决方法.实验结果表明,该方法可有效地降低传感器的同频干扰,传感器的信噪比由1.53提高至35,为传感器闭环激励和检测提供了有效的手段.     

热激励谐振式硅微结构压力传感器

对一种以方形硅膜片作为一次敏感元件;硅梁作为二次敏感元件的硅谐振式压力微传感器进行了研究:建立了微传感器敏感结构的数学模型;敏感结构参数:方形膜边长4 mm,膜厚0.1 mm,梁谐振子长1.3 mm,宽0.08 mm,厚0.007 mm;对原理实验样件采用电热激励、压阻拾振方式作了开环测试,讨论了传感器的闭环系统.     

热激励谐振式硅微结构压力传感器闭环系统

讨论了一 执 式硅微结构压力传感器闭环系统。该谐振式硅微结构压力传感器以方形硅膜片作为一次敏感元件;硅梁作为二次敏感元件。在硅梁谐振子的中部设置一电阻,作为热激励单元;在梁的要部设置一压敏电阻,作为拾振单元。基于该夺式硅微结构压力传感器敏感机理,分析了信号的相互转换,给出传感器闭环系统实现的条件。     

基于SOI-MEMS工艺的谐振式压力传感器研究

提出了一种电磁激励、差分检测的谐振式MEMS压力传感器,该器件采用低电阻率的SOI器件层单晶硅制作“H”型谐振梁,并作为激励和检测电极。根据对传感器数学模型的分析,利用有限元分析方法优化了传感器结构设计。采用等离子深刻蚀制作传感器结构,并用湿法腐蚀SOI二氧化硅层的方法释放。利用硅-玻璃阳极键合技术,实现了传感器的圆片级真空封装。采用开环扫描检测和闭环自激振荡方式,测定压力传感器的特性。实验结果表明：传感器一致性良好,在500~1100hPa的检测范围内,差分检测灵敏度为14.96Hz/hPa,线性相关系数为0.999996。     

一种新型微机械谐振式压力传感器研究

提出了一种微机械谐振式压力传感器的新结构.该传感器采用了电磁激励和差分检测方式.谐振器的制作采用了30μm厚扩散硅的(100)硅片.从而实现了谐振器与压力膜的一体化,避免了谐振梁与压力膜键合引入的应力,并且工艺简单易于实现.文中介绍了结构的有限元仿真(FEA-ANSYS Simulation)优化,工艺制作流程,及实验测试.在低真空下测试其品质因数(Q)高于10 000,测量范围为0～100 kPa,非线性度为0.62%,分辨率为1/10 000,灵敏度为200 Hz/kPa.     

基于三梁结构的电热驱动谐振式微加速度传感器研究

为了提高电热激励/压阻拾振谐振式微加速度传感器的品质因数和消除交叉灵敏度,提出一种基于三梁结构的新设计.依据有限元模拟得到的固有振型来选择三梁结构参数,以减少能量耗散,提高品质因数.分析本设计消除交叉灵敏度的机制和独特的三梁结构的激振方式并对其进行有限元模拟.模拟结果证实这种谐振式微加速度传感器的灵敏度高于1000 Hz/g.     

谐振式压力传感器驱动仿真研究

谐振式传感器由于其重量轻、精度高、响应快在压力测量领域获得了飞速发展,传感器的构成包括机械谐振子在内的机电一体的谐振系统,而驱动系统对保持机械谐振器振荡的稳定性和可靠性起着重要作用.本文针对一种典型结构的谐振式压力传感器,分析比较了不同的闭环驱动结构,最后构建了其行为级闭环自激仿真模型,在MATLAB中对自激回路的起振情况进行了仿真;验证了AGC对压力传感器幅度与频率的双重跟踪性.     

微型硅谐振式压力传感器的研制

利用微电子机械加工技术成功地研制出电热激励、压阻拾振的高精度硅谐振梁式压力传感器。传感器的谐振器的品质因素Q值在真空中大于 10 0 0 0。采用特殊闭环自激振荡方式测定压力传感器的压力特性 ,压力测试范围 0～ 40 0kPa ,线性相关系数 0 .9999,测试精度优于 0 .1%FS。     

微结构谐振梁式压力传感器研究

利用微电子机械加工技术成功地研制出电势激励、压阻拾振的高精度硅谐振梁式压力传感器,传感器的谐振器的品质因素Ｑ值大于１７０００。采用扫描检测方式和闭环自激振荡方式测定压力传感器的压力特性,其压力测试范围为０￣４００ｋＰａ,线性相关系数为０．９９９９５,测试精度小于０。０６％Ｆ．Ｓ。     

An electrothermally excited dual beams silicon resonant pressure sensor with temperature compensation

An electrothermally excited dual beams silicon resonant pressure sensor with temperature compensation is proposed in this paper. One beam locates upon the diaphragm, whose resonant frequency changes with the measured pressure; the other beam is on the fixed edge, isolated from the pressure effect but sensitive to the temperature variation. Taking the difference of the dual beams’ resonant frequencies, temperature influence can be corrected. Compensation algorithm with consideration of the fabrication errors is deducted theoretically and implemented by a homemade readout system. Experimental results of the test sample indicates that the maxim pressure measurement residual errors without compensation is up to 53.9 kPa in the working temperature range from −40 to 60°C; while with compensation the maxim residual errors decreased to 1.8 kPa from −40 to 60°C, which is only 3.3% of the uncompensated sensor. The experimental results confirm that the new designed sensor has good temperature compensation ability.     

电磁激励谐振式MEMS压力传感器闭环控制研究

在谐振器动力学分析的基础上,系统地比较了谐振式压力传感器检测速度谐振频率和检测位移谐振频率的优缺点.设计出一种零相移的电磁激励谐振式MEMS压力传感器闭环控制系统,该系统利用检测速度谐振频率提高传感器的信号检测稳定性,并且控制电路无需移相环节即可保证传感器在工作频率范围内实现稳定可靠的闭环自激.实验结果表明,采用该闭环控制系统的传感器具有较高的稳定性,传感器长时漂移低于0.025%F.S.,在10 hPa～1 050 hPa范围内非线性度为0.06%.     

飞行大气参数测试仪的研制

设计了一款适用于高海拔、宽温域条件的飞行大气参数测试仪.基于PC104和ARM处理器组成的主从式CPU架构,构建了飞行大气参数测试仪的硬件平台,采用高精度硅谐振式压力传感器实现了对气体压力的测量;基于PID与分级误差控制相结合的控制方法,通过PWM驱动的高速电磁阀,实现了对气压的精密控制.     

基于SOI的硅微谐振式压力传感器芯片制作

采用SOI硅片,基于MEMS技术,设计并加工了一种新型三明治结构的硅微谐振式压力传感器,根据传感器敏感单元的结构设计,制定了相应的制备工艺步骤,并且针对湿法深刻蚀过程中谐振子的刻蚀保护等问题,提出了一种基于氮化硅、氧化硅和氮化硅三层薄膜的保护工艺,实验表明,在采用三层薄膜保护工艺下进行湿法刻蚀10 h后,谐振子被完全释放,三层薄膜保护工艺对要求采用湿法刻蚀镂空释放可动结构具有较高的实用价值。最后对加工完成的谐振式压力传感器进行了初步的性能测试,结果表明,在标准大气压力下谐振子的固有频率为9.932 kHz,品质因数为34。     

Analysis and design for piezoresistive accelerometer geometry considering sensitivity,resonant frequency and cross-axis sensitivity

Presented in this paper is the geometrical analysis and design for piezoresistive accelerometers. An improved figure of merit (FOM), considering sensitivity, resonant frequency and cross-axis sensitivity, is established to evaluate the sensor characteristics. Three conventional geometries, including cantilever-beam, quad-beam and cross-beam, are investigated to explore the influence from sensor configurations on the FOM. Based on the obtained results, a multi-beam structure is developed to provide an available solution to the drawback of low FOM in normal geometries. The proposed design increases its resonant frequency at the cost of a slight loss in sensitivity, and declines the cross-axis sensitivity by the specific configuration, which is made possible by incorporating two tiny sensing beams into the quad-beam structure. The simulated FOM is about 5.5 times of the conditional structures. The fabricated prototype is characterized for static parameters and resonant frequency. Experimental results show that the measured FOM is about 4.85 × 10⁹ Hz², much higher than the existing designs in literatures or on the market.     

Resonant frequency sensitive MEMS bandpass filter using capacitive sensing scheme

This paper presents the theoretical and experimental behaviour of microelectromechanical bandpass filters. The proposed bandpass filter can detect frequencies of monitoring structures with high sensitivity using the resonant frequency of micro-resonator of sensor. The micro-resonator contains a proof mass and four supported beams fabricated using a bulk silicon micromachining technology on a silicon-on-insulator wafer. When applying an external force to the system, the device generates a capacitance change, which is converted into a voltage by an electrical circuitry. In good agreement with finite element simulations of the device, experimental results validate that the filter has a center frequency of about 3.3 kHz, a 3 dB bandwidth of 0.562 kHz and a quality factor Q of 5.9 in atmospheric pressure. This paper demonstrates a parallel-resonator filter to increase a monitoring bandwidth. A 3 dB bandwidth of the parallel filter is measured to be 1.25 kHz at atmospheric pressure.     

Micro devices for a cerebrospinal fluid (CSF) shunt system

This paper reports a novel cerebrospinal fluid (CSF) shunt system for the hydrocephalus patients. The CSF shunt system consists of a micro telemetry pressure sensor, an electromagnetic micropump and a controller. The pressure sensor has a flexible p+ diaphragm and a planar copper coil that construct an LC resonant circuit. The cerebrospinal pressure is measured from the phase shift at the resonance frequency. The micropump consists of an actuator diaphragm and a pair of passive valves. Each device is fabricated by micromachining technology and tested to obtain the characteristic. The feasibility of the proposed shunt system is evaluated with the in vitro performance test.     

基于硅谐振压力传感器的大气数据系统的实现

详细介绍了Druck RPT 200型硅谐振压力传感器的工作原理,阐述了大气数据系统的结构、建模及硬件实现等研制过程;该系统采用Druck RPT 200型硅谐振压力传感器替代原振动筒式压力传感器测量压力,并采用小型单板计算机作为大气数据系统的嵌入式计算机,实现高度、空速和马赫数等参数的计算,并由显示器实时显示;该大气数据系统体积和重量仅为原系统的1/10,并具有高精度、高分辨率,高稳定性和高重复性的特点。