V型电致热微驱动器的力学特性分析

运用能量法推导并建立了一种V型悬臂粱电热微致动器的力学模型.利用该力学模型得到了致动器的力学特性,并且与相关的实验结果进行了对比.由理论分析和实验对比发现,用于制造该电热微致动器的多晶硅材料在微米级尺度下的热膨胀系数与温度之间不再遵循宏观状态下的线性函数关系.     

MEMS微致动器的研究

MEMS技术在未来的发展中有着重要的意义。本文介绍了MEMS微致动器和各类驱动模式的优缺点,并以微泵为例,详细比较了致动器的执行机制和原理。     

V型电致热微驱动器的力学特性分析

运用能量法推导并建立了一种V型悬臂粱电热微致动器的力学模型。利用该力学模型得到了致动器的力学特性 ,并且与相关的实验结果进行了对比。由理论分析和实验对比发现 ,用于制造该电热微致动器的多晶硅材料在微米级尺度下的热膨胀系数与温度之间不再遵循宏观状态下的线性函数关系     

微型热致动器研究

本论文围绕微型热致动器的研制开发,对热致动方式进行较为深入研究,利用硅微细加工工艺制造出多种型热致动器,并进行了理论分析和实验测试。     

V型电致热微驱动器的力学特性分析

运用能量法推导并建立了一种V型悬臂粱电热微致动器的力学模型。利用该力学模型得到了致动器的力学特性，并且与相关的实验结果进行了对比。由理论分析和实验对比发现，用于制造该电热微致动器的多晶硅材料在微米级尺度下的热膨胀系数与温度之间不再遵循宏观状态下的线性函数关系。     

磁性液体的微致动性能

针对磁性液体在MEMS微致动器中的应用,对磁性液体在磁场中致动力的影响因素进行了理论分析。根据理论分析结果设计了一套磁性液体微致动性能测试实验台,并从磁场强度、磁性液体受力面积和磁性液体质量三个方面对其微致动性能进行实验研究。实验结果表明:磁性液体致动力与磁场强度近似呈线性关系;等量磁性液体作用面积越大,致动力越大;磁性液体致动力随磁性液体质量的增加不断增加,当磁性液体质量达到一定值时,磁性液体致动力大小趋于稳定。     

多晶硅衬底上的RF MEMS开关

在微机械开关与硅IC工艺设计和兼容方面进行了改进,获得了一种可与IC工艺兼容的RF MEMS微机械开关.采用介质隔离工艺技术把这种RF MEMS微机械开关制作在绝缘的多晶硅衬底上,实现了与IC工艺兼容;采用在金属膜桥的端点附近刻蚀一些孔的优化方法,降低了RF MEMS微机械开关的下拉电压.用TE2819电容测试设备测试开关的电容,测得开关的开态电容、关态电容和致动电压分别为0.32pF、6pF和25V.用HP8753C网络分析仪对RF MEMS微机械开关进行了RF特性测试,得出RF MEMS微机械开关在频率1.5GHz下关态的隔离度为35dB,开态的插入损耗为2dB,用示波器测得该开关的开关速度为3μs.     

老年人健康信息管理系统的开发与应用

从电路模型上分析多路复用技术在压电微变形镜控制中的驱动特性,设计了基于双MOSFET开关的驱动电路,并对致动器的电压保持能力和抗干扰能力做了测试.实验和分析表明,一个高压运放驱动25个压电陶瓷(PZT)致动器时,工作频率可达400 Hz,致动器的变形控制精度在2%左右.与传统控制方法相比,该方法具有低功耗、低成本的优点,适用于自适应光学系统中多通道压电微变形镜的控制.     

一种MEMS热驱动可变电容的分析模拟

文中设计并分析了一个MEMS热驱动可变电容,它的下极板固定于衬底,上极板通过热致动器驱动。热致动器由冷臂和热臂组成,一端通过锚点固定于衬底,一端连接在电容器上极板。热驱动器通过电压驱动使MEMS电容器上极板上下运动。文中作者使用有限元方法模拟了150～300μm加热臂长在0～4 V电压条件下的电容变化值和温度变化,有限元模拟结果表明其电容变化率最大可达10倍。     

扭转微镜光学致动器研究

应用基于表面硅、体硅微电子工艺的混合微加工技术研制了新型扭转微镜光学致动器,实现了致动器结构与具有光纤自固定、自对准功能的新型光纤定位保持结构的单片集成.新型扭转微镜光学致动器的机电和光学特性研究表明,其工作寿命超过108次动作,最小动作时间估计可低于2ms,存在驱动微镜自然地翻转90°角的静电阈值电压和维持微镜处于已翻转90°角状态的静电最低保持电压;其微镜的表面粗糙度及其分布基本满足光的波分复用技术等的应用要求.新型扭转微镜光学致动器可在光纤网络中作为光开关或可变光衰减器使用.设计、制作及研究了由新型扭转微镜光学致动器组成的2×2光开关阵列.     

电磁驱动推拉式射频MEMS开关的设计与制作

提出了一种新型电磁驱动推拉式射频MEMS开关。针对传统静电驱动单臂梁开关所需驱动电压大、恢复力不足等问题,设计了一种推拉式开关结构,降低了驱动电压(电流),提高了开关的隔离度,同时实现了单刀双掷的功能。单晶Si梁由于自身无应力,解决了悬臂梁残余应力引起的梁变形问题。通过理论计算和有限元分析,优化了开关设计尺寸,在外围永磁铁磁感应梯度dB/dz=100T/m,在线圈通入100mA电流的驱动下,单晶Si扭转梁末端可以获得约10μm的弯曲量,满足开关驱动要求。给出了开关的详细微细加工流程,对开关的传输参数进行了测试,在10GHz时隔离度为-40dB.     

一种新型低压电容式RF MEMS开关的设计与分析

介绍了一种基于扭转的新型低压电容式RFMEMS开关的设计.此开关在保留传统挠曲变形的基础上,引入了扭转变形,并利用Intelli Suite等软件进行仿真分析.理论分析和仿真结果表明:与传统弯曲变形不同,在扭转变形中,变形对臂的厚度远比宽度敏感;在保留传统挠曲变形的基础上,增加了扭转变形,将有效降低驱动电压.理论分析还表明增长扭转臂、从动臂可使驱动电压明显下降.通过优化结构设计,在扭转臂、从动臂长为180μm、120μm,臂宽为5μm,厚为1μm,驱动电极面积为120μm×120μm时,仿真得到驱动电压为1.5V.     

Metallic Glass as a Mechanical Material for Microscanners

Microelectromechanical system (MEMS) actuators essentially have movable silicon structures where the mechanical motion can be activated electronically. The microscanner is one of the most successfully commercialized MEMS devices which are widely used for collecting optical information, manipulating light, and displaying images. While silicon is abundant, it is also brittle and stiff and when microprocessed, defects are not uncommon. These defects result in weakness under torsional stress and this has been the key factor limiting the scanning performance of the microscanner. Here a metallic glass (MG)‐based microscanner is reported with MG as the material for the moving torsion bars. The low elastic modulus, high fracture toughness, and high strength of MG offers, for the first time, an ultralarge rotating angle of 146° with power consumption lowered to the microwatt range, and a smaller driving force and better actuation performance, than conventional single crystal silicon and polycrystalline silicon. The high spatial resolution and large scanning field of the MG‐based microscanner are demonstrated in the tomographic imaging of a human finger. This development of an MG‐based MEMS possibly opens a new field of low‐powered MEMS devices with extreme actuation and enhanced sensing.     

Analysis and optimization of two movable plates RF MEMS switch for simultaneous improvement in actuation voltage and switching time

An attempt to overcome the existing limitations of RF MEMS switch like high actuation voltage and low switching time simultaneously has been addressed by introducing the concept of moving bottom plate (CPW central line).The performance characteristics of such MEMS switch with two movable plates has been analyzed by setting up the continuity equation of both the plates and solving it analytically with valid approximations. It is seen that for all practical cases such two movable plate designs can be represented by a single movable plate with equivalent membrane parameters. It is observed that a simultaneous reduction of both the actuation voltage and switching time around 20% is possible by optimizing the dimensions. Alternatively a maximum reduction of 30% in the actuation voltage is possible keeping the switching time unaltered and the switching time can be reduced by 50% keeping the switching voltage unaltered. Closed form expressions for the actuation voltage and switching time are obtained which are seen to match with the numerical results.     

一个DC-32GHz两位微机械移相器

采用分布式微机械传输线结构实现了两位移相器,并且为了减小传输线负载电容和驱动电压首次提出了用共面波导传输线来驱动微机械桥的结构(共面波导驱动结构).结果显示驱动电压小于20V,20GHz时两位移相器的相移为0°/20.1°/41.9°/68.2°,插入损耗为-1.2dB.在DC到32GHz的范围内相移具有良好的线性,插入损耗小于-1.8dB,反射损耗好于-11dB.实验结果表明了该结构在高介电常数衬底上制造低插损、宽带数字微机械射频移相器的潜力.     

Harnessing the Actuation Potential of Solid‐State Intercalation Compounds

High‐strain, high‐force mechanical actuation technologies are desirable for numerous applications ranging from microelectromechanical systems (MEMS) to large‐scale “smart structures” that are able to change shape to optimize performance. Here we show that electrochemical intercalation of inorganic compounds of high elastic modulus offers a low‐voltage mechanism (less than 5 V) with intrinsic energy density approaching that of hydraulics and more than a hundred times greater than that of existing field‐operated mechanisms, such as piezostriction and magnetostriction. Exploitation of the reversible crystallographic strains (several percent) of intercalation compounds while under high stress is key to realization of the available energy. Using a micromachined actuator design, we test the strain capability of oriented graphite due to electrochemical lithiation under stresses up to 200 MPa. We further demonstrate that simultaneous electrochemical expansion of the LiCoO₂/graphite cathode/anode couple can be exploited for actuation under stresses up to ～ 20 MPa in laminated macroscopic composite actuators of similar design to current lithium‐ion batteries. While the transport‐limited actuation mechanism of these devices results in intrinsically slower actuation compared to most ferroic materials, we demonstrate up to 6.7 mHz (150 s) cyclic actuation in a laminated actuator designed for a high charge/discharge rate. The potential for a new class of high‐strain, high‐force, moderate‐frequency actuators suitable for a broad range of applications is suggested.     

Design of a novel MEMS resonator based neuromorphic oscillator

A novel MEMS based neuromorphic oscillator is presented. Due to compatibility with CMOS process, on-chip integration of electro-statically actuated microresonators is possible with very small size. Also, taking advantage of sacrificial sidewall spacer technique for fabrication of 100 nm vertical gap, as low actuation voltages as 0.5 V is enough for such resonators. Oscillatory neuron dynamics are also studied and design of the resonator and its characteristics are described as a neuromorphic oscillator. There are several practical barriers associated with MEMS implementation of neuromorphic oscillators such as existence of near-to-main mode spurious modes, requiring of UHF high gain trans-impedance amplifier because of very high motional resistance of such resonators, and automatic amplitude control circuit which all investigated in the paper and surmounted as well. A coupling technique for weak connection of such resonators is also described in the paper which allows mechanical low velocity connection of UHF contour mode disk resonators for the first time.     

Reliability testing of flexible printed circuit-based RF MEMS capacitive switches

In this paper, reliability results of a novel type of electrostatically actuated RF MEMS capacitive switches developed by our group are discussed. The test setup used for reliability testing consists of the capacitive MEMS switch under test connected in series with a resistor. A specified actuation waveform is applied to the switch and the voltage waveform across the resistor is continuously recorded. The recorded waveform aids in identifying short, open, or stiction failure of the switch. Further, the waveform recorded can be analyzed to study the degradation, reliability, and lifetime characteristics of the switch. The proposed method has been used to study the reliability, failure, and hold-down test characteristics of flexible circuit-based RF MEMS switches. Reliability testing up to 75 million operations has been carried out for flexible circuit-based RF MEMS switches.     

Single-pole-double-throw switch based on toggle switch

A single-pole-double-throw (SPDT) switch based on the toggle switch, a new type of radio frequency (RF) microelectromechanical (MEMS) switch structure for low voltage actuation, high broadband application and enhanced power capability, is presented. Electromagnetic simulation results are discussed and the fabrication process and measurement results are given. The SPDT switch exhibits low insertion loss (<0.5 dB at 20 GHz) and high isolation (>28 dB at 30 GHz).     

高过载姿态测量中MEMS陀螺失效模式与研究进展

高过载条件下姿态测量是一个公认的难题,其原因主要是角速度传感器难以经受高过载的冲击。基于微机电系统（MEMS）技术的陀螺作为解决高过载姿态测量问题的核心器件,其抗高过载能力直接制约着惯性导航系统在高过载环境中的应用。首先,介绍了弹药发射和侵彻两种典型高过载环境的特性,概括了在高过载环境中MEMS陀螺的响应类型;其次,总结了高过载条件下MEMS陀螺的失效模式,包括完全失效和功能性失效;然后,介绍了国内外在抗高过载MEMS陀螺方面的研究进展;最后,分别从器件设计和工程应用角度出发,提出了MEMS陀螺抗高过载的设计方法和应用思路。