Fabrication and dynamic analysis of the electrostatically actuated MEMS variable capacitor

Future microwave networks require miniature high-performance tunable elements such as switches, inductors, and capacitors. In this paper, high performance variable capacitor was fabricated by simple microelectromechanical systems (MEMS) technology. The capacitance and quality (Q) factor at 1 GHz are 0.792 pF and 51.6. The pull-in voltage is 13.5 V and the tuning ratio of the capacitor is more than 1.31:1. A reduced-order model for the dynamic characteristics of the capacitor is established based on the equilibrium among the plate flexibility.     

Experimental verification of a design methodology for torsion actuators based on a rapid pull-in solver

In this work, an experimental and theoretical study of the effect of various geometrical parameters on the electromechanical response and pull-in parameters of torsion actuators is presented. A lumped two-degrees-of-freedom (L2DOF) pull-in model that takes into account the bending/torsion coupling, previously proposed for cantilever suspended actuators, is tailored for the torsion actuators under study. This model is shown to better capture the measured pull-in parameters than previously proposed lumped single-degree-of-freedom (L1DOF) models. The measurements were conducted on torsion actuators with various shapes, fabricated on silicon-on-insulator (SOI) wafers using deep reactive ion etching (DRIE) and flip-chip bonding. Furthermore, a novel rapid solver, for extracting the pull-in parameters of the L2DOF model of the torsion actuators, is proposed. The proposed solver is based on a Newton-Raphson scheme and the recently presented DIPIE algorithm and is shown to be /spl sim/10 times faster than the prevalent voltage iterations based solvers. The rapid and more accurate pull-in extraction of the proposed approach renders it as a tool for extensive analysis and design optimization of torsion actuators.     

基于超级电容器储能的时域激发极化法发射机研究

针对目前时域激发极化法发射机存在无电能存储、体积较大的问题,设计了一种基于超级电容器储能的时域激发极化法发射机。该发射机采用新的电路拓扑结构,在发射机空闲时由超级电容器存储发电机输出的能量,在发射机工作时超级电容器释放存储的能量,释放出的能量与发电机一起给负载提供功率,有效减小了发电机的体积;同时超级电容器在释放能量时与发电机电源是串联工作,不仅不需要升压电感而且能够实现升压作用,进一步优化了发射机的体积。仿真及实验结果表明,该发射机性能稳定、可靠。     

一款基于开关电容的倍压器研究与设计

基于开关电容的倍压器又称为电荷泵,设计将电荷泵集成到一颗芯片中.该芯片能够在4 V至20 V的输入范围内工作,并提供7 V至38 V的输出,提供超过10 mA的输出电流.电路采用电荷泵结构实现倍压,该电路的特点是无需电感,就可实现对输入电压的倍增,消除了电磁干扰的影响.空载情况下电源电流最大不超过12mA.另外该电路采...     

静电悬浮式三轴加速度传感器的初步设计

从静电悬浮式加速度传感器的工作原理出发 ,针对航天器上的微重力水平 ,初步设计了高灵敏静电悬浮式加速度传感器 ,其测量量程设计为 30 μgn,分辨力为 1ngn,并对其误差来源及减少误差的措施进行了分析。     

基于模态分析的静电驱动圆薄板宏模型建立方法

为了研究静电致动圆板静态和动态特性,在模态分析法的基础上,利用多维非线性函数的Levenberg-Marquardt拟合方法,将板的动能、弹性能和电容写成以模态坐标表示的解析式.结合Hamilton原理,导出静电致动微圆板的动力学特性方程的宏模型.以此为基础研究了板的静态特性及其三角波、方波信号激励下的动态响应.结果表明,模态分析方法能够考虑到残余应力的影响,所建立的动态宏模型不仅大大地减少了计算费用,而且具有足够的仿真精度.     

超级电容监控系统的自保护设计

大电流放电实验系统中,超级电容监控系统存在硬件损坏、软件崩溃、通信失联等问题。为此,提出了解决电源故障、HMI故障、超级电容通信故障、PLC故障的自保护方案,解决了监控系统自身失效的检测和保护问题。最后,对实际开发的超级电容监控系统自保护功能进行了测试,结果表明,该自保护设计方案确实是可行和有效的。     

基于AD7150微小电容测量方法的研究

本文主要研究了一种新型的微小电容的测量方法,阐述了电容测量电路的应用背景和国内外研究现状,针对电容式传感器的工作原理确定了测试电路。AD7150是一种响应快速兼超低功耗的电容－数字转换器,通过串行接口与微控制器连接,为电容式近程传感器的信号处理提供了一种全面的解决方案。     

基于单形正交实验设计的差分演化算法

为了克服传统差分演化(DE)算法在求解约束优化问题时出现的收敛性慢和容易陷入早熟等缺陷,提出一种新的基于单形正交实验设计的差分演化(SO-DE)算法。该算法设计了一种结合单形交叉和正交实验设计的混合交叉算子来提高差分演化算法的搜索能力;同时采用了一种改进的个体优劣比较准则对种群个体进行比较和选择。这种新的混合交叉算子利用多个父代个体进行单形交叉产生多个子代个体,从两者中选择优秀个体进行正交实验设计得到下一代种群个体。改进的个体优劣比较准则对不同状态下的种群采用不同的处理方案,其目的在于能够有效地权衡目标函数值和约束违反量之间的关系,从而选择优秀个体进入下一代种群。通过对13个标准测试函数和2个工程设计问题进行仿真实验,实验结果表明SO-DE算法求解的精度和标准方差都要优于HEAA算法和COEA/OED算法。SO-DE算法具有更高的精度以及更好的稳定性。     

Investigation of actuation voltage for non-uniform serpentine flexure design of RF-MEMS switch

This paper presents an attempt to reduce the actuation voltage of capacitive RF-MEMS switch by introducing the concept of non-uniform serpentine flexure suspensions. The spring constant of non-uniform serpentine flexure with different meander sections have been equated by analytical expression and verified with finite element method (FEM). FEM analysis indicate actuation voltage as low as 5 V with single meander section for the proposed non-uniform serpentine spring design, which is reasonably low as compared to uniform serpentine spring with same span beam length.     

一种基于电容倍增的无电容式LDO

设计了一种基于电容倍增的无电容式LDO,将电容倍增模块嵌入到了误差运算放大器的第一级,提升了系统的环路带宽,有良好的瞬态响应。电路通过0.13μm标准CMOS工艺仿真实现,仿真结果显示,系统静态功耗为42μW,当负载从0⁵0 mA变化时,电压最大波动为87 mV,建立时间为2.5μs。     

基于FPGA的新型强弱混合型PUF电路设计

物理不可克隆函数(PUF,physically unclonable function)通过提取芯片制造过程中无法避免引入的工艺偏差,可产生具有随机性、唯一性和防篡改特性的特征密钥.通过对PUF电路结构和工作原理的研究,提出一种基于现场可编程门阵列(FPGA,field-programmable gate array)...     

A design methodology for a bulk-micromachined two-dimensional electrostatic torsion micromirror

This paper presents a design methodology for a two-dimensional (2-D) electrostatic torsion micromirror fabricated with bulk-micromachining technology. The theoretical models in mechanical and electrostatic fields presented here provide insights into the influences of different design parameters on micromirror performance. Parametric numerical models built in ANSYS are used to more accurately predict its performance and further refine the design parameter values derived from the theoretical models. By use of the electrical analogy method, an equivalent electrical circuit is built in PSPICE to predict the static and dynamic performance of this micromirror, with the numerical simulation results as the input parameters. The equivalent electrical circuit has been demonstrated to be a simple and powerful approach to characterize the performance of this 2-D torsion micromirror. The test results for this micromirror reveal very good agreement between experimental and numerical results, taking into account fabrication tolerances and experimental accuracies. Incorporating the fabrication tolerances of bulk-micromachining technology, this design methodology can be readily applied to performance characterization and design optimization.     

RMS voltage sensor based on a variable parallel-plate capacitor made of electroplated copper

We present an advanced RMS voltage sensor based on a variable parallel-plate capacitor using the principle of electrostatic force. The device is fabricated in a micromechanical surface process with a high-aspect ratio actuator, reinforced by copper electroplating employing a sacrificial photo-resist layer. Another copper layer with a coplanar waveguide below the actuator provides separated excitation and sensing electrodes. Flip-chip technology is employed for low-loss electrical connectivity. The presented design has a plate area of up to 3 × 3 mm² and an initial gap distance of only 1.5 μm. We present results achieving a pull-in voltage below 1 V at frequencies from DC up to 1 GHz and sensitivities up to 1 fF/mV.     

基于混合遗传算法的去耦电容网络设计

结合基于目标阻抗的设计方法,将混合遗传算法应用于PDN(电源分配网络)的去耦电容网络设计,对所需去耦电容器的种类和数目进行优化计算,同时与标准遗传算法和传统设计方法进行对比,借助Cadence电源完整性仿真工具验证设计结果的有效性和合理性。避免了传统设计需要借助EDA工具进行反复修改和验证的繁琐过程,同时减少了设计冗余,节省了PCB布局布线空间,为高频电路的PDN设计提供参考。     

基于电平转换器的物理不可克隆函数电路设计

提出一种基于通用交叉耦合电平转换器的低开销新型物理不可克隆函数的电路设计.该设计只需在传统电平转换电路中引入一个额外的开关晶体管,用来切换电平转换器的差分工作模式和共模工作模式,利用交叉耦合网络中两个PMOS晶体管由于开关速度不同所引起的输出电压的不确定性,通过共模模式输出获取所必需的熵值.该电路采用标准65 nm C...     

基于全桥串联谐振的电容器充电理论研究

分析研究了全桥串联谐振充电电源电路,通过求解电路动态方程,进一步推导分析,得出基于全桥串联谐振开关电源技术电容器恒流充电的理论通式,利用MATLAB仿真研究,对通式做了初步验证,对该领域的研究具有理论指导意义。     

On the tunability of a MEMS based variable capacitor with a novel structure

In this work a novel MEMS based variable capacitor has been presented. To increase the tunability and decrease the applied voltage, the conventional fixed-fixed beam used in CPW lines has been changed to a fixed-simple supported beam. The proposed structure is a simple cantilever micro-beam in the first step of deflection and is changed to a fixed-simple supported micro-beam in the second step of motion. In the capacitive micro-structures increasing the applied voltage decreases the equivalent stiffness of the structure and leads the system to an unstable condition by undergoing to a saddle node bifurcation. In the proposed structure to avoid pull-in instability and increase the capacitance tuning range, mechanical stiffness of the structure is increased by changing boundary conditions by locating a pedestal in the end of the cantilever beam. The governing nonlinear equation for static deflection of the micro-beam, based on Euler–Bernoulli micro-beam theory has been presented. The results show that the proposed structure increases the capacitance tuning range and decreases the applied voltage. The results also show that the position of the pedestal affects the tunability and the threshold voltage of the structure.     

基于灵敏度分析的白车身扭转刚度优化

为提高某量产车型白车身(Body in White,BIW)扭转刚度,提出一种基于灵敏度分析的BIW刚度优化方法.深入阐述灵敏度分析原理和车身刚度优化策略,分析该车型车身开发中的37个低成本横向构件的料厚变化对BIW扭转刚度的影响.通过对BIW有限元模型的计算和分析,验证优化策略并对比优化前后的BIW扭转刚度性能.结果表明该方法以较低成本就可达到车身扭转刚度的较大提高.