Young's modulus characterization of low-k films of nanoporous Black DiamondTM by surface acoustic waves

The laser-generated surface acoustic wave(SAW) technique is an accurate,fast and nondestructive solution to determine the mechanical properties of ultra thin films.SAWs are dispersive during the wave propagation on the layered structure.The Young's moduli of thin films can be obtained by matching the experimentally and theoretically calculated dispersive SAW curves.A short ultraviolet laser pulse is employed to generate the broad spectral range of the dispersive SAWs.The frequency range of dispersive SAW...     

声表面波方法表征低k纳米多孔黑钻石绝缘薄膜的杨氏模量

激光激发声表面波技术探测薄膜的杨氏模量是一种快速、准确、无损的方法。在薄膜表面,声表面波通过激光短脉冲与介质材料之间的热弹作用被激发。在分层结构的薄膜上传播时,表面波会发生色散现象,通过对实验测得的表面波色散曲线和理论计算的到的色散曲线进行匹配,可以获得薄膜的杨氏模量。在本实验中,采用紫外波段激光脉冲可以产生具有很宽频谱范围的表面波信号,色散曲线的范围可达180 MHz。应用声表面方法对生长于Si(100)衬底上,具有不同厚度的低k纳米多孔黑钻石绝缘薄膜的杨氏模量进行了成功探测。     

SAWDIC: surfaceacoustic-wave-driven directional coupler

Optical directional couplers are driven by surfaceacoustic waves. Two effects can be distinguished: single and double frequency modulation. Experiments have been performed between 180 MHz and 430 MHz SAW frequency at light wavelength 0.633 ?m with modulation depth up to 100%.     

小型化双通带声表滤波器设计研究

针对小型化双通带声表面波(SAW)滤波器的需求背景,对两端口、两通带的SAW滤波器的设计技术展开研究。通过搭建包含两组耦合模(COM)参数的双通带SAW滤波器声电协同仿真平台,分析优化滤波器性能,成功研制出CSP2520封装的双通带SAW滤波器,其中心频率分别为1 995 MHz和2 185 MHz,通带带宽均为40 MHz,插入损耗小于3 dB,通带间隔离度大于30 dB。测试与仿真结果基本一致。     

二端网络声表面波滤波器电磁仿真分析及设计

为了模拟高频低损耗声表面波(SAW)滤波器的设计,该文采用二端口阻抗元2T结构建立了包含外壳及点焊线电磁响应的数学模型,并利用回路电流分析法,推导出该模型下的Y、S参数。且在该模型基础上用Matlab编写了程序,为某电台设计了一款频率为1 561 MHz,-1 dB带宽大于30 MHz,插入损耗小于2 dB,带外抑制大于40 dB的SAW滤波器,理论模拟与实测吻合较好,表明了此模型在设计高频低损耗SAW滤波器的可行性。     

甚高频高性能SAW滤波器

对甚高频（ＵＨＦ）高性能ＳＡＷ滤波器干扰模式采用了一种新的处理方法,即采用梯形ＳＡＷ单元网络与微带组合电路构成ＳＡＷ滤波器,用微带电路对干扰模式进行抑制。设计过程简洁,可采用成熟的ＳＡＷ单元电极和叉指参数进行计算机模拟,且当所设计的滤波器通带频率和带宽变化时,参数调整方便。并成功地用于９１４ＭＨｚ,带宽１７ＭＨｚ滤波器的设计。     

Extension of time-bandwidth product in SAW spectrum analysers

Surface-acoustic-wave (SAW) spectrum analysers use the chirp transform algorithm for real time analysis over wide (MHz) signal bandwidths. This letter reports a new technique for the generation of the long-duration wideband linear frequency modulated (chirp) waveforms used in these analysers. It now permits the overall time bandwidth product of these spectrum analysers to exceed that of the constituent SAW filters, and has consequent application in analysis of communication signals. An externally programmable weighting technique, for optimising time sidelobe suppression is also demonstrated.     

基于声表面波的喇曼型声光移频器的研究

A Raman acousto-optic frequency shifter （AOFS） based on surface acoustic wave （SAW） is presented. It consists of a double-ended SAW resonator and optical waveguide system. The structure parameters of the SAW resonator are optimized using COM software and the optical waveguide system is designed using an effective index method. The AOFS prototype fabricated using MEMS technology is detected. The optical beat signals su- perimposed by ± 1st-order and ±2nd-order diffracted beams are detected. The frequency shift of 78.2201 MHz related to the 1 st-order diffracted beams and 156.2306 MHz related to the 2nd-order diffracted beams are obtained respectively.     

基于纵向耦合结构的宽带声表面波滤波器设计

基于纵向耦合五换能器结构,采用41°-YX-LiNbO3基片材料,通过优化设计,研制出中心频率232 MHz,3 dB带宽23.5 MHz的声表面波滤波器。该产品的插入损耗-3 dB,相对带宽达到10.1%,矩形系数小于2.5,阻带抑制大于40 dB,产品综合性能指标优异,有很好的实用性。     

一种扇形结构小型化中频声表面波滤波器

该文研究了一种扇形结构的声表面波设计技术并分析了其工作原理及加权方式,为某电台接收机设计并制作了一款中心频率为374 MHz、-3 dB带宽大于17 MHz、插入损耗小于9.5 dB、通带波纹小于1 dB、带外抑制大于40 dB(10~352 MHz)的器件。将该器件封装在表贴SMD3838小型外壳中,其满足性能指标。结果表明,该器件首次突破了扇形结构中频声表面波滤波器在表贴SMD3838封装的研制,表明扇形结构声表面波滤波器产品实现小型化的可行性。     

基于SAW谐振器无源无线传感器编码方法研究

为简化声表面波(SAW)传感器的编码过程,提出了一种基于SAW谐振器的编码方法,通过多个不同中心谐振频率的SAW谐振器分别连接不同的负载阻抗进行传感器的编码。设计了传感器的具体结构,建立了传感器的等效电路模型,利用ADS仿真软件对中心谐振频率分别为868MHz和915MHz的2个SAW谐振器组成的传感器进行仿真,结果表明,SAW谐振器外接1pF与4pF的阻抗,其谐振频率差可达200³00kHz。根据仿真结果,设计制作了不同编码的2个传感器,一个不外接阻抗,一个外接10pF的阻抗,测试谐振频率差别可达39.75300kHz。根据仿真结果,设计制作了不同编码的2个传感器,一个不外接阻抗,一个外接10pF的阻抗,测试谐振频率差别可达39.75⁴0.2kHz,因此,SAW谐振器外接不同阻抗时谐振频率的差异明显,基于SAW谐振器与外接阻抗的传感器编码方法是可行的。     

声表面波器件的封装技术及其发展

目前各种声表面波器件的工作频率涵盖30MHz到3000MHz的频率范围,其封装形式主要有塑料封装、金属封装(如F11、TO-39)和sMD封装。在本文中,作者对声表面波器件的这三种主要封装形式对声表面波器件电传输性的影响作了系统的实验研究与分析,并论述了声表面波器件在封装方面的现状及其发展趋势。     

Composite substrate material for surface acoustic-wave oscillator

Surface acoustic-wave (SAW) oscillators have advantageous features compared with other technologies. The Y-128° LiNbO₃ is a well-known, high electromechanical-coupling SAW material, but its usefulness is limited because of its poor temperature-stability property. The AlN films have some excellent characteristics, such as high SAW velocity, stable chemical properties, and high-temperature stability. In this research, different thickness AlN films were sputtered on Y-128° LiNbO₃ to be a composite substrate for the SAW oscillator. As AlN film thickness increased, the temperature coefficient of frequency (TCF) value of the oscillator varied from −76.32 ppm/°C to −28.81 ppm/°C giving an improvement in the TCF of 62.25%. The oscillator frequency at 25°C also varied from 40.0909 MHz to 41.6221 MHz, giving an improvement in the oscillator frequency of 3.8%. The composite substrate (AlN/Y-128° LiNbO₃) can enhance the oscillator frequency and effectively improve the poor temperature stability for the SAW oscillator.     

声表面波VCO的研制

介绍了１５５．５２ＭＨｚ、６２２．０８ＭＨｚ声表面波（ＳＡＷ）、１２４４．１６ＭＨｚ浅体波（ＳＴＷ）压控振荡器（ＶＣＯ）的原理、设计和性能。采用低插损、高Ｑ值的ＳＡＷ延迟线和ＳＴＷ谐振器，高性能微波放大器，变容二极管电移相器，使振荡器具有非常低的相位噪声（＜－１４０ｄＢｃ／Ｈｚａｔ１００ｋＨｚ）、高输出功率（＞９ｄＢｍ）、低温度－频率漂移（＜±３５ｐｐｍ，温度范围：－５～６０℃）、大频率调谐范围（＞４００ｐｐｍ）。     

空军总医院全军临床航空医学中心简介

通过建立声表面波(SAW)匹配滤波器的等效能量结构,利用交叉场电路等效模型,在频域上对SAW匹配滤波器进行分析.对于中心频率为60 MHz、抽头数32位的SAW匹配滤波器,采用上述方法得到的插入损耗和-3 dB带宽的计算值和测试值分别相差小于1 dB和1 kHz,证明了其正确性和有效性.     

Integrated Circuit Compatible Surface Acoustic Wave Devices On Gallium Arsenide

Improvements in gallium arsenide materials technology have led to the rapid development of GaAs MIC, CCD, and digital IC technologies in the last several years. In this paper we consider the additional capabilities afforded by the inherent piezoelectric properties of GaAs. The primary emphasis of the work is on surface acoustic wave (SAW) device configurations using MESFET and Schottky-barrier diode fabrication techniques which are compatible with the eventual monolithic integration of electronic devices on the same substrate. The GaAs SAW technology described here provides a means for achieving electronically variable delay, high-Q resonator structures for VHF/UHF oscillator frequency control, and real-time signal processing operations such as convolution and correlation. Prototype device designs and performance are described, includlng two-port GaAs SAW resonators with Q's as large as 13 000 at 118 MHz and a programmable GaAs SAW PSK correlator capable of signal correlation at 10-MHz chip rates. Further GaAs SAW device development required for increasing the operating frequency range to 500 MHz and processing bandwidth to 100 MHz is indicated.     

高性能声表面波调频振荡器的研究

分析了声表面波谐振器的性能 ,论述了声表面波振荡器的工作原理及设计方法 ,最终完成中心频率为797.3 MHz的振荡电路 ,调频带宽 2 MHz(2 5 0 0 PPM)。文中对影响调频带宽、相位噪声的因素进行了分析讨论。本项目研究成果已获得实际应用     

低插损极窄带声表面波滤波器设计

利用集总参数等效电路模型计算了声表面波双模耦合谐振滤波器的频响．通过改变谐振器各个参量使滤波器指标满足要求．在ＳＴ石英基片上成功研制出中心频率２２８ＭＨｚ，△ｆ－３ｄＢ＝１５０ｋＨｚ，插损为３ｄＢ，阻带抑制小于－５０ｄＢ的铁路专用寻呼机用滤波器。理论计算与实验结果一致。     

光敏型聚酰亚胺对声表面波传输损耗的研究

采用扰动理论推导了聚酰亚胺薄膜作为声表面波的吸声材料时,声表面波的传输损耗模型。利用网络分析仪对表面涂覆厚5μm光敏型聚酰亚胺薄膜的双声路SAW传感器(中心频率165 MH z)的插入损耗进行测试,对理论模型进行了实验验证。理论结果表明,聚酰亚胺薄膜造成SAW的传输损耗和传感器的中心频率的高低、聚酰亚胺薄膜的厚度以及聚酰亚胺薄膜的宽度成正比。实验测试也证明,聚酰亚胺薄膜对声表面波造成的传输损耗和宽度成正比关系,测得传输损耗为9.5 dB/mm。     

声表面波阅读器扫频信号源设计与实现

声表面波阅读器分为基于时域采样和频域采样两种类型.在频域采样的声表面波阅读器实现过程中,性能良好的扫频信号源不可或缺.基于直接数字频率合成技术和锁相环频率合成技术设计了一个中心频率,扫频范围和步进频率都可控制调节的信号源,并加入了功率放大电路对扫频信号进行放大.实际制作了信号源硬件电路,对单一频点、扫频信号和功率放大模块逐一进行了测试,并分析了频率点的锁定过程.测试结果表明,信号源实现了中心频率940 MHz,扫频范围为933.75～946.25 MHz步进频率为125 kHz,功率为15 dBm的设计目标.