Electrostatic tuning in linear regime for 25.9-MHz micromechanical resonator with 120-nm capacitive gap

Microsystem Technologies - In this paper, electrostatic tuning in the linear regime for a high-frequency single-crystal silicon resonator is investigated. An electrostatic actuated I-shaped bulk...     

岩石饱和度阵列耦合谐振器的研究

大多岩石饱和度检测设备存在精度低、结构单一的问题,依据岩石含水量与介电常数之间线性关系,设计一种以耦合微带环阵列结构的饱和度谐振检测系统.根据岩石介电常数变化,微带环产生不同谐振频率和Q值求,通过谐振参数反演岩石介电常数求得饱和度.研究工作包括微带环结构设计仿真,阵列结构设计,系统硬件设计.岩石样本测试显示阵列结构具有更高精度,误差＜0.95％.这种新型阵列传感器系统精度高、体积小适合岩石饱和度检测.     

压阻式金刚石压力传感器的优化设计

介绍了一种新型金刚石高温压力传感器的优化设计方法.采用薄板弯曲理论研究了均匀载荷作用下多晶金刚石方膜在小挠度和大挠度下的应变分布情况.对设计时应当考虑的主要问题包括金刚石力敏电阻条的掺杂浓度,电桥的形式,电阻条在膜片上的分布以及电阻条的有效长度和形状等进行了讨论.利用模拟程序确定了力敏电阻条的最优有效长度,分析了敏感膜片厚度,方块电阻等因素对电阻条有效长度和输出响应的影响.     

压阻式金刚石压力传感器的优化设计

介绍了一种新型金刚石高温压力传感器的优化设计方法。采用薄板弯曲理论研究了均匀载荷作用下多晶金刚石方膜在小挠度和大挠度下的应变分布情况。对设计时应当考虑的主要问题包括金刚石力敏电阻条的掺杂浓度，电桥的形式，电阻条在膜片上的分布以及电阻条的有效长度和形状等进行了讨论。利用模拟程序确定了力敏电阻条的最优有效长度，分析了敏感膜片厚度，方块电阻等因素对电阻条有效长度和输出响应的影响。     

硅纳米悬臂梁传感结构压阻特性的试验研究

为了研究拉伸和大形变弯曲共存状态下硅纳米悬臂梁传感结构的压阻特性,采用CMOS工艺制作了硅纳米悬臂梁传感测试结构,结合原子力显微镜和半导体参数测试仪对其电学参数进行了测量,其位移灵敏度高达1.58216×10-4/nm。在电阻相对变化率实验测量和ANSYS有限元平均应力仿真的基础之上,进而提出了一个非线性压阻模型来提取大弯曲硅纳米悬臂梁的一阶和二阶压阻系数。研究结果表明:其一阶压阻系数约为体硅的5倍,该巨压阻效应为利用硅纳米压阻传感结构来实现超高灵敏度的纳米压力传感器提供了可能的途径。研究结果同时也揭示了要获得高的灵敏度和好的可靠性,硅纳米悬臂梁的长度设计需要折衷考虑。     

谐振式微机械加速度计设计的关键技术

谐振式微机械加速度计直接输出频率信号,具有稳定性好、精度高的特点.分析了谐振式微机械加速度计的工作机理,建立了第一级敏感结构、杠杆机构和第二级敏感结构的数学模型,指出了实现高灵敏度加速度测量的关键技术在于支撑梁、质量块、谐振器和杠杆机构的设计.提出了一种谐振式微机械加速度计结构,进行了结构的优化设计和仿真计算,得出的性能指标:谐振频率98 858 Hz,Q值673.9,灵敏度24.52 Hz/gn.     

Si基微环谐振腔化学传感检测方法研究

提出了一种非标记光化学传感检测方法：光波导谐振谱检测,通过感应环形波导表面有效折射率变化进行化学传感;理论分析,并结合光学测试系统,利用此方法实现了微环谐振腔结构对NaCl离子、结晶紫分子溶液的在线浓度测量,实验得到：其检测灵敏度分别达181.47 pm/10－2,227 nm/（ mol·L－1）,证明了该方法可以应用于化学溶液检测领域。     

声表面波谐振器无源无线传感虚拟仪器系统

分析了在通用硬件平台上结合软件设计的声表面波谐振器无源无线传感虚拟仪器系统。该系统通过设计虚拟仪器实现部分硬件功能,控制闭环系统实现自动检测,并采用数字信号处理方法提高检测系统的精度,从而避免了通常的复杂硬件系统,降低硬件成本,并使检测更灵活。本文介绍了设计原理和系统构成,并对系统的误差进行了分析。实验表明:该仪器系统能够达到5m的无线检测距离。     

Magnetic field sensing using magnetic-fluid-filled optofluidic ring resonator

A magnetic field sensor based on the silica optofluidic ring resonator is proposed and experimentally demonstrated for the first time. Magnetic fluid is filled in the core of the microcapillary to experience the strength change of the applied magnetic field. When the whispering gallery modes circulate in the wall of the microcapillary, it can experience the increasing refractive index of magnetic fluid with the increase in the magnetic field strength, leading to the redshift of the resonant wavelength. The maximum sensitivity of 75.7 pm/mT and figure of merit of 105 T^?1 are realized, respectively, corresponding to a large dynamic magnetic field range from 15 to 125 mT. By optimizing the concentration of the kerosene-based magnetic fluid, the detection limit of 2.2 mT and the measurement resolution of 0.9 mT are achieved, respectively. This work provides a novel magnetic field sensing scheme with high performance using the optofluidic ring resonator and further broadens its applications.     

Analysis and design of a new piezoresistive tactile sensor system for robotic applications

The development of an experimental tactile sensor system fitted on a robot work-table is analyzed in this paper. In the first stage of this research a 16 × 16 piezoresistive sensor was used, attached on the work-table of an ASEA IRB-2000 robot. The keypoint of the above design is that the sensor is not used just to obtain texture information, as it is happens when it is fitted on the gripper, but also to obtain tactile data from the object nonvisible base-surface and finally the object weight. The experimental system is designed so as to allow variation in the design parameters to determine the best set of parameter values for optimal performance of the sensor. Experiments carried out show the operability of the above system and, furthermore, the advantages using this sensor topology.     

Genetic algorithm based framework for optimized sensing matrix design in compressed sensing

Multimedia Tools and Applications - Sampling matrices used in compressed sensing framework are mostly randomly structured and thus inefficient in terms of memory utilization, reconstruction speed,...     

无源声表面波谐振器的无线温度传感系统

介绍了一种基于声表面波谐振器的无源无线温度传感系统。作为传感器的谐振器受到正弦脉冲串的无线激励。因激励信号的中心频率不同于谐振器的谐振频率，所以回波信号是一调幅信号，其包络的主频就是谐振器的谐振频率和激励信号中心频率的差频。给出了传感系统的电路设计以及信号处理方法。实验数据和器件的温度系数吻合。     

超高频体模式MEMS谐振器及其传感系统平台技术研究

针对体模式MEMS谐振器激励和响应信号的特点,设计集成了激励信号产生和微弱信号检测的传感测量系统。系统通过对谐振器的扫频激励和检测响应信号,可以准确测量谐振器的谐振频率和Q值特性。为了有效测量谐振器产生的高频微弱位移电流信号,系统设计使用频谱搬移的测量方法。该方法通过把包含在高频信号中的有效信息搬移到低频端进行信号处理,可以提高信号抗噪声的能力,实现对微安量级的高频电流放大检测。     

Battery sensing for energy-aware system design

The battery lifetime of small, powerful, portable devices can determine their viability. Developers can use mathematical models derived from battery energy measurements to infer a battery's state-of-charge (SoC) and then use the results to implement fuel gauging techniques in real electronic designs.     

Performance optimization of SiC piezoresistive pressure sensor through suitable piezoresistor design

Microsystem Technologies - Silicon carbide is considered as a more suitable material for piezoresistive pressure sensors in a high-temperature environment due to its excellent characteristics. In...     

The effect of piezoresistive microcantilever geometry on cantilever sensitivity during surface stress chemical sensing

We have designed, fabricated, and tested five piezoresistive cantilever configurations to investigate the effect of shape and piezoresistor placement on the sensitivity of microcantilevers under both point loading and surface stress loading. The experimental study reveals that: (1) high aspect ratio cantilevers that are much longer than they are wide are optimal for point-loading applications such as microscopy and force measurements; (2) low aspect ratio cantilevers that are short and wide are optimal for surface stress-loading scenarios such as those that occur in biological and chemical sensor applications. The sensitivity data for both point loads and surface stress are consistent with previously developed finite-element models.     

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.     

Materials selection in micromechanical design: an application of the Ashby approach

The set of materials available to microsystems designers is rapidly expanding. Techniques now exist to introduce and integrate a large number of metals, alloys, ceramics, glasses, polymers, and elastomers into microsystems, motivating the need for a rational approach for materials selection in microsystems design. As a step toward such an approach, we focus on the initial stages of materials selection for micromechanical structures with minimum feature sizes greater than 1 /spl mu/m. The variation of mechanical properties with length scale and processing parameters is discussed. Bounds for initial design values of several properties are suggested and the necessity for the measurement of other properties (especially residual stresses and intrinsic loss coefficients) is discussed. Adapting the methods pioneered by Ashby et al., materials indices are formulated for a number of properties and materials selection charts are presented. These concepts are applied to illustrate initial materials selection for shock-resistant microbeams, force sensors, micromechanical filters, and micromachined flexures. Issues associated with the integration of materials into microsystems are briefly discussed.     

Optimal design of high-g MEMS piezoresistive accelerometer based on Timoshenko beam theory

Microsystem Technologies - The high-g micro-electro-mechanical systems (MEMS) piezoresistive accelerometers are designed based on silicon-on-insulator (SOI) to be used in explosion and penetration...     

基于改进PSO算法的嵌套环式微陀螺结构优化设计

摘要：改变嵌套环陀螺的结构设计会引起陀螺性能发生很大的改变,但由于其结构复杂,参数众多,导致陀螺在仿真过程中计算量过大,难以探索陀螺多参数变量对陀螺性能的影响规律,针对这一问题提出了一种基于改进PSO算法的嵌套环陀螺结构优化设计方法。该方法在传统PSO算法寻优的基础上,引入极值扰动来避免算法陷入局部极值,并针对嵌套环陀螺进行了一定的条件约束,解决了多参数在总和固定情况下的优化问题。改进后的优化算法以机械热噪声为目标函数,在波音设计的陀螺模型基础上对其间隙分布进行了优化实验,并与未优化前进行了性能对比,结果表明,改进后的优化算法使嵌套环陀螺性能显著提高,结构优化设计更加高效简洁,适用于嵌套环陀螺进行各种多参数的优化问题。