共查询到20条相似文献,搜索用时 78 毫秒
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基于有限元压电材料中表面波传播的有限元分析原理,利用有限元分析软件COMSOL对基于ZnO单晶材料的声表面波器件进行多物理域耦合建模与仿真,提取出了符合声表面波振型的对称模态变形图和反对称模态变形图。通过谐振频率分析,计算出了ZnO单晶的相速度和机电耦合系数;通过频率响应分析,得出谐振器输入导纳、阻抗与频率之间的关系图;最后讨论了叉指换能器的结构对谐振频率、反谐振频率的影响,得出输入、输出叉指换能器(IDT)的叉指电极对数越大,插入损耗值越大,信号衰减越小。 相似文献
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该文研究了1-3-2压电复合材料的厚度振动谐振频率与尺寸的关系。应用压电学和弹性动力学理论建立了机电等效图,对1-3-2压电复合材料的厚度振动模态进行了机电理论分析,并对其谐振频率进行了计算。利用有限元仿真软件分析了在厚度振动模态下,1-3-2压电复合材料谐振频率、反谐振频率与尺寸变化的关系。结果表明,纵向尺寸比变大时,频率曲线呈下降趋势;横向尺寸比变大时,频率曲线呈上升趋势;横纵尺寸比变大时,频率曲线呈缓慢下降趋势;基底厚度变大时,频率曲线呈先减小后增大趋势。4种情况中,纵向尺寸比对于整体的谐振和反谐振频率影响最显著。 相似文献
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压电式微固体模态陀螺谐振频率自动跟踪电路 总被引:2,自引:2,他引:0
压电式微固体模态陀螺振子通过交变电压激振、传感电极感应出电荷。当激励电压频率为某阶振动模态谐振频率时,感应电荷达到最大值。设计了谐振频率自动跟踪电路,使陀螺稳定工作在谐振模态。使用现场可编程门阵列(FPGA)控制直接数字频率合成器(DDS)产生频率精确可调的激励电压,驱动陀螺振子振动。检测谐振点对应的激励电压和感应信号间的相位差,作为反馈信号调节激励电压频率。实验结果表明,当相位差锁定区域处在98.48°~100.27°时,振子感应电极输出信号最大,振子处于谐振状态,实现了振子谐振频率的跟踪锁定。该系统可用于以谐振器为核心器件的振子工作模态锁定与跟踪。 相似文献
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为了抑制薄膜体声波谐振器(FBAR)的寄生谐振同时满足5G通信的高频需求,基于Comsol Multiphysics仿真软件建立薄膜体声波谐振器的二维和三维有限元模型,研究了压电材料、电极横向尺寸和电极形状对寄生谐振的影响,并讨论了电极框架结构对FBAR并联谐振频率(fp)处的品质因数(Qp)的影响。基于分析,提出并设计了一种双阶梯电极框架结构的FBAR,该结构的FBAR以AlN为压电材料,电极形状为五边形,中心频率为3.504 GHz,串联谐振频率为3.467 GHz,并联谐振频率为3.541 GHz,Qp为1591。Qp与未优化的FBAR相比提高了19.2%,实现了对寄生谐振的有效抑制。 相似文献
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薄膜体声波谐振器(FBAR)电极层和压电层的厚度、材料是影响谐振频率的主要因素,确定各层的厚度和材料可得到期望的谐振频率。通过推导FBAR纵向运动应力方程,得到各层厚度、材料、频率参数与角频率相关的公式;采用MATLAB对FBAR各层应力和位移的边界、连续性条件方程组的行列式进行牛顿迭代,得到各层的频率参数。将确定的各层厚度、材料参数值及由牛顿迭代得到的频率参数值代入公式,可以得出谐振频率为1.453 8GHz。采用ADS对具有与公式计算相同厚度、材料的FBAR进行纵向振动Mason模型等效电路仿真,得到仿真模型的谐振频率为1.463GHz。仿真验证结果表明,谐振频率公式计算值和模型仿真值较近,可采用频率公式计算L波段FBAR纵波谐振频率。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test. 相似文献
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The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high. 相似文献
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The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation. 相似文献
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Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible. 相似文献
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GU Min-fen LIANG Zhong-cheng WANG Ren-zhou DONG Xiang-mei ZHANG Pei-ming CHEN Jia-bi 《光电子快报》2008,4(2):150-152
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's. 相似文献
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It is a key problem to accurately calculate beam spots' center of measuring the warp by using a collimated laser. A new method, named double geometrical center method (DGCM), is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device (CCD) is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What's more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high. 相似文献
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The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well. 相似文献
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Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems. 相似文献