声表面波谐振器无源传感信号特性和信号处理方法研究

无源无线声表面波谐振器传感信号是一个低信噪比、瞬态衰减信号,并叠加有激励信号和信道噪声.本文利用信号统计特性,显著地提高信噪比,获取谐振频率所在区间,让激励频率在该区间内取值,使之逼近谐振频率,从而达到检测谐振频率的目的.     

无源无线SAW传感虚拟仪器系统设计及性能分析

本文介绍了一种采用声表面波谐振器作为传感器的虚拟仪器系统.该仪器系统采用虚拟仪器技术取代部分传统仪器,引入数字信号处理方法和反馈控制,通过无线激励查询传感信号,提取信号特征并显示测量结果.系统提高了测量精度和测量距离,可进行多种参数的测量,能够自动捕捉被测参量并跟踪其变化.     

精密确定声表面波谐振器等效参数

本文介绍了有约束的内点惩罚函数—阻尼最小二乘法,并通过“内点罚函数——Powell法”与“内点罚函数——阻尼最小二乘法”相结合的新尝试,精密地确定出了声表面波谐振器的七个等效参数。计算结果比已经报导过的更加精确。结果表明本算法是精密确定SAWR等效参数的有效方法。     

声表面波无源无线温度传感系统研究

本文提出了一种单端口声表面波无源无线温度传感系统。该传感系统采用间歇正弦脉冲串信号作为无线激励信号，而反射波是一调幅信号，该调幅信号的包络频率为激励信号频率与声表面波器件固有频率的差，该传感系统提高了遥感的距离并且减小了环境对固有频率测量的影响。     

声表面波直线电动机的原理与应用

从声表面波的产生机理入手,介绍声表面波直线电动机的结构,定性分析声表面波直线电动机中存在的关键问题,并探讨了该电动机在精确定位系统中的诱人前景。     

声表面波传感器电路参数的CAD方法

本文提出了声表面波传感器电路参数的一种ＣＡＤ方法，即有约束内点惩罚函数－鲍威尔－阻尼最小二乘法，并对两个实例进行了计算。     

双声路声表面波传感器测量系统研究

环境温度对声表面波传感器影响较大,常采用双声路结构补偿环境温度的影响,本文结合声表面波器件结构,设计了一种新的测量系统。它由交替工作的延迟线振荡器、混频电路和数字信号处理电路组成。延迟线振荡器输出信号经滤波后与109MHz的本机晶体振荡器输出信号相混频,通过低通滤波取其差频,并经整形后由数字信号处理电路处理。应用标准信号源验证了测量系统的准确性,频率跟踪特性误差在50Hz以内。测量系统显示直观,精度高,是双声路声表面波传感器理想的测量系统。     

声表面波无线测温技术在钢铁企业变电站的应用

针对高压开关柜温度不易监测问题,提出了基于声表面波技术的无线无源传感器温度监测新方法,使用该检测手段实时在线监测高压开关设备内的温度。对声表面波温度传感器的结构及声表面波无线无源温度系统的组成部分进行了阐述,经实际应用案例表明,运用该技术搭建的温度监测系统大大提高了钢铁企业供电设备的在线监测水平,具有安装方便、测量精度高、运行安全可靠等优点。     

T91钢管外表面纵向缺陷超声检测技术

针对现有超声表面波检测标准不适用于电站锅炉受热面管表面缺陷检测的问题,分析了超声表面波检测探头声束入射角和入射点在T91钢管外表面的变化规律,根据T91钢管规格尺寸和超声波在钢中横波传播的声速,设计了合理的探头声束入射角和入射点,制作了人工缺陷对比试块,并与自然缺陷试块进行了比较,制定出合理的检测工艺。实际应用结果表明:本文设计的探头和工艺具有较高的灵敏度和信噪比,解决了电站锅炉钢管超声表面波检测无现行参考标准的问题,也为其他小径管纵向线性缺陷的检测提供了借鉴。     

无源传感器的研究与应用进展

无源传感器件将传感信号和供电电源合二为一,实现了传感器的自主能源供给,解决了传感器系统的供电难题。主要阐述了声表面波型和基于能源材料的无源传感器的基本原理、种类、性能特点及其在电网中应用的发展现状,并通过对声表面波型、压电型、热电型等国内外典型无源传感器性能参数的综合分析比较,提出我国今后高性能无源传感器的主要研究方向及其在未来智能电网建设中的应用前景。     

Sensors based on saw resonator with “nontraditional formats” of output signal

It is demonstrated that the sensitivity of sensors based on two-port surface acoustic waves (SAW) resonators increases by a factor of Q (Q-loaded quality factor of the resonator) if the output signal of these sensors is represented in the phase format instead of the conventional frequency format. Practical possibility of use of the SAW gas sensor with phase format of transmitted signal as output signal is demonstrated using procedure of the determination of the water contents in gaseous nitrogen with 386 MHz ST-quartz SAW resonator as an example. It is found that the SAW power affects the sensor response owing to the influence of the SAW intensity on the equilibrium amount of water molecules adsorbed on the resonator surface. Extremely high sensor sensitivity was obtained when using phase format of reflected signal as a sensor output. Using such a format of sensor output we have reliably measured the change of temperature of ST-quartz SAW sensor substrate as small as 0.01^∘C.     

Modeling of a wireless saw temperature sensor and associated antenna

Surface acoustic wave (SAW) resonator used as wireless sensor was characterized and the parameters of its MBVD ((Modified Butterworth-Van Dyke) model were extracted versus temperature. The extracted parameters lead to evaluate the resonator performances in terms of Temperature coefficient of frequency (TCF) and quality factor (Q). An antenna was then associated with the SAW resonator and the entire system has been characterized and modeled. The good agreement experiment-simulation allows to define the optimum operating conditions of the wireless sensor.     

Wireless and batteryless SAW sensors,a promising solution for harsh environments

In this paper,general principle of the Surface Acoustic Wave(SAW) sensor in wired and wireless con-figurations will be developed and a review of recent works concerning the field of high temperature applications will be presented.The first part will be devoted to aspects of data transmission and processing.Both configurations of SAW de-vice,delay line and resonator,will be discussed as well as the remote interrogation techniques used to collect and to proc-ess signal.The second part will be devoted to the material aspects.Indeed,knowing that the conventional piezoelectric substrates such as quartz or lithium niobate cannot be used at high temperature,the choice of the material constituting the SAW device(substrate & electrodes) is one of the challenges to face.We will focus our discussion on the Langasite,the current reference for high temperature applications,and on the AlN/Sapphire structure,the very promising alternative for application where the use of high frequency is required.     

A Novel Wireless Passive Temperature-Pressure SAW-based Sensor

A novel wireless and passive surface acoustic wave (SAW) sensor is developed for measuring temperature and pressure. The sensor has two single-port resonators on a substrate. One resonator, acting as the temperature sensor, is located at the fixed end without pressure deformation, and the other one, acting as the pressure sensor, is located at the free end to detect pressure changes due to substrate deformation. Pressure at the free end bends the cantilever, causing a relative change in the acoustic propagation characteristics of the SAW traveling along the surface of the substrate and a relative change in the resonant frequency of the resulting signal. The temperature acts on the entire substrate, affecting the propagation speed of the SAW on the substrate and directly affecting the resonant frequency characteristic parameters. The temperature and pressure performance of this new antenna-connected sensor is tested by using a network analyzer, a constant temperature heating station, and a force gauge. A temperature sensitivity of 1.5015 kHz/°C and a pressure sensitivity of 10.6 kHz/gf at the ambient temperature have been observed by wireless measurements. This work should result in practical engineering applications for high-temperature devices.     

绝缘子温湿度在线监测技术研究

为降低绝缘子发生污闪的概率,需对影响绝缘子泄漏电流的温湿度值进行在线监测。为克服现有的在线监测温湿度技术在高环境温度和强电磁干扰等各种恶劣的环境下可靠性低的不足,采用了一种新的基于声表面波射频识别(SAWRFID)的绝缘子温湿度在线监测方法。首先对该SAW-RFID温湿度传感器标签芯片进行了通信测试、中心频率测试和性能测试,并基于该温湿度传感器对XP-70型绝缘子进行了实验,利用SAW-RFID温湿度传感器标签监测绝缘子温湿度,在此基础上分析得到了环境温湿度与绝缘子泄漏电流幅值的关系,为预估绝缘子绝缘性能提供了参考依据。     

Effects of rapid thermal annealing on surface acoustic wave ultraviolet sensors using ZnO nanorods grown on AlN/Si structures

In this study, we demonstrate a high sensitivity of surface acoustic wave (SAW) ultraviolet (UV) sensor based on ZnO nanorods (NRs) grown on an aluminum nitride (AlN)/silicon (Si) layered structure. The one-dimensional ZnO NRs act as a high-UV sensing material due to their large surface-to-volume ratio. The fabrication of SAW UV sensor is entirely compatible with micro/nano electromechanical (M/NEMS) process with conventional lithography and synthesized ZnO NRs by hydrothermal method at low temperature. The rapid thermal annealing (RTA) process effectively improved the optical properties of ZnO NRs and the sensitivity of the SAW UV sensors. The resulting SAW UV sensors responded to various UV light intensities, and the RTA-processed samples showed high sensitivity. The SAW UV sensor after RTA treatment at 600 °C showed the highest sensitivity with a 130 kHz frequency shift at a UV light intensity of at 0.6 mW/cm², a 5-fold increase in sensitivity compare with as-grown sample.     

Laboratory Experiments in Surface Acoustic Wave Devices and Their Applications

This project relates to the development of three novel laboratory experiments for electrical engineering seniors enrolled at the Polytechnic Institute of New York introducing them to surface acoustic wave (SAW) devices and their applications. Major developments in this new technology have taken place during the past decade. SAW devices now play a significant role in the signal processing area and industries' strong interest in this new technology is now evident. The first experiment in the series demonstrates the fundamental behavior of SAW devices using the delay line structure. The second experiment relates to the measurement of the complex impedance of the SAW interdigital transducer. The third experiment demonstrates how the SAW device can be used to perform the function of convolution and correlation.     

折线型IDT的SAW微力传感器设计研究

声表面波(SAW)微力传感器易于集成和小型化,无源无线的工作方式,具有极大的应用潜力.将其应用于物体间微间隙压力检测有望实现高灵敏、低功耗的监测水平.针对复杂环境中存在的测量灵敏度问题,设计了一种具有折线形状的叉指换能器(IDT)的SAW微力传感器.采用有限元分析方法(FEM)对其进行了仿真分析和结构参数设计.理论分析...     

GA-BP神经网络对SAW压力传感器测量数据的拟合

随着传感技术的不断发展,出现了越来越多以传感器为基础的无线传感检测系统.这些传感系统需要对采集到的数据进行数据分析.因此,传感器的数据分析对于无线传感系统的精确检测起到至关重要的作用.首先对设计的声表面波(surface acoustic wave,SAW)微压力传感器进行实际测量,利用最小二乘法建立数学模型,对测得的...