共查询到20条相似文献,搜索用时 203 毫秒
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本文主要从声表面波传感器基础理论出发,首先分析了声表面波技术的发展,对声表面波传感器结构模型和工作模式特性做了必要的分析和研究,进而展开了对声表面波传感器敏感特性研究。并对仿真效果进行了扼要的总结,对声表面波技术在相关感领域的应用,本文也展开了一定的探讨。 相似文献
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基于周期台阶表面声阻抗理论,解释了"水鸣天梯"声景观的物理机制。首先在低频准平面波近似的情况下,利用阻抗转移公式得到了周期台阶单元表面声阻抗。数值解表明,在低频段台阶表面的声阻抗呈现纯容抗性,证实了表面波的存在。有限元软件仿真的结果与理论分析保持一致。应用表面波的性质,设计并进行了现场试验。试验数据分析表明:在台阶底部脚踏石阶或者发射脉冲声波,声波经过台阶表面作用,到达台阶顶部时只有低频部分的声能量得到了较大保留,与理论分析和模拟结果相一致,最终确定了正是周期台阶的表面波滤波效应使得脚踏声转变为悦耳的水滴声。 相似文献
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一种计算声表面波在周期栅阵中传播特性的方法 总被引:1,自引:1,他引:0
Hashimoto有限元程序是日本Chiba大学研究人员从1973年开始、历时几十年用Fortran语言编写、计算声表面波在周期栅阵中传波特性的一个软件包。该程序能计算Rayleigh波、漏表面波、SH型表面波、表面横波等多种声表面波的传输特性,同时它能适用于一个周期内单根指条、两根指条和多根指条及声表面波在栅阵中斜入射的情况。该程序已在声表面波(SAW)研究人员中得到了广泛的应用。 相似文献
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Miniaturized SAW filters using a flip-chip technique 总被引:1,自引:0,他引:1
Yatsuda H. Horishima T. Eimura T. Ooiwa T. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1996,43(1):125-130
This paper describes a miniature surface acoustic wave (SAW) filter, 3.2×2.5×0.9 mm3, which is applicable for radio frequency (RF) stage filters in mobile phones. The SAW filter is reduced in size by using a flip-chip assembly technique. The technique uses gold bumps on the SAW chip and gold-gold thermosonic face-down bonding. The gold bumps are formed onto the wafer by a conventional wire bonding machine using gold wire. The thermosonic face-down bonding enables the connection of gold bumps on the SAW chip, with gold metallized pads, on a ceramic package at a temperature below 200°C. This bonding ensures that the SAW chip is fixed mechanically, and connected electrically, with the package. Frequency responses of a 950-MHz flip-chip SAW filter are compared with responses of a SAW filter with a conventional package. The results of reliability tests for flip-chip SAW filters are shown 相似文献
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Dai E Feng G He Z Cui D 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1997,44(2):309-314
The majority of investigations of SAW devices used as chemical sensors are based on delay line oscillators. However, SAW resonator oscillator offers some advantages over the SAW delay line oscillator for its higher stability. In the incipient stage of fabricating gas sensors based upon SAW resonator, taking detection of organic vapor as an example, the analysis method that combines the SAW theory with organic film technology has been adopted to give an intensive insight into the responses of two-port SAW resonator coated with LB-film and cast-film after exposure to organic vapors. 相似文献
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Reindl LM Shrena IM 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(11):1457-1463
Surface acoustic wave (SAW) devices can be used as wireless sensor elements, called SAW transponders, for measuring physical quantities such as temperature that do not need any power supply and may be accessed wirelessly. A complete wireless sensor system consists of one or more such SAW transponders and a local radar transceiver. The SAW transponder receives an RF burst in the VHF/UHF band transmitted by the radar transceiver. The reader unit performs a radar measurement of the impulse response of the SAW transponder via a high-frequency electromagnetic radio link. A temperature variation changes the SAW velocity and thereby the response pattern of the SAW device. By analyzing the time delay between backscattered pulses with different time delays we get a rough estimation of the temperature of the SAW transponder. By using this information the ambiguity of +/-2pi in the phase differences between the pulses can be eliminated, which provides an overall and unambiguous temperature resolution of +/-0.2 degrees C. 相似文献
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Yamanaka K. Nagata Y. Nakano S. Koda T. Nishino H. Tsukahara Y. Cho H. Inaba M. Satoh A. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1995,42(3):381-386
We present principle and application of a novel noncontact velocity measurement of surface acoustic waves (SAW) on crystals and thin films using laser interference fringes scanned at the phase velocity of SAW. The scanning interference fringes (SIF) are produced by intersecting two laser beams with a frequency difference. The SAW velocity within the laser beam spot is measured as the ratio of observed SAW frequency and predetermined wave number of the SIF. The frequency measurement can be quite precise because of a large number of generated SAW carriers and amplitude enhancement effect. The SAW velocity measurement is free from the water loading effect accompanying the leaky SAW measurements. This principle was successfully applied to evaluate Si 3N4 and SiO2 films deposited on Si (001) surface 相似文献
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Theory and application of passive SAW radio transponders as sensors 总被引:15,自引:0,他引:15
Reindl L Scholl G Ostertag T Scherr H Wolff U Schmidt F 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1998,45(5):1281-1292
Surface acoustic wave (SAW) radio transponders make it possible to read identification codes or measurement values from a remote location. The decisive advantage of these SAW transponders lies in their passive operation (i.e., no power-supply), and in the possibility of wireless installation at particularly inaccessible locations. The passive SAW transponders are maintenance free. Identification marks respond to an interrogation signal with their nonchanging identification pattern. In wireless SAW sensors the physical or chemical properties to be detected change the propagation characteristics of the SAW. SAW radio transponders are advantageously placed on moving or rotating parts and in hazardous environments such as contaminated or high voltage areas. They also can be used for contactless measurements in high vacuum process chambers, under concrete, extreme heat, or strong radioactive radiation, where the use of conventional sensors is complicated, dangerous, or expensive. In this paper we discuss the principles of wireless passive SAW transponders and present a radio frequency interrogation unit and several passive radio SAW sensors developed for noncontact measurements of temperatures, pressures, torques, and currents. 相似文献
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Smith DA Johnson JJ 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1993,40(1):22-25
A SAW waveguide directional coupler that was used to provide a raised-cosine apodization of the SAW beam intensity, in order to achieve sidelobe suppression of an integrated acoustooptic filter, is demonstrated. The SAW guide coupler consisted of two closely spaced, evanescently coupled parallel acoustic waveguides. A single guided SAW mode was excited by a miniature transducer imbedded in a 100-mum-wide waveguide, and in excess of 99% of the SAW energy was transferred from the original waveguide to the coupled guide, and back, across a gap of 20 mum. The coupling length (for complete crossover) was 9.8 mm and depended exponentially on gap, as expected. This SAW coupler resulted in 10-dB sidelobe suppression compared to an unapodized acoustooptic filter. 相似文献
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Differential phase shift keying direct sequence spread spectrum single SAW based correlator receiver 总被引:1,自引:0,他引:1
Moeller F Belkerdid MA Malocha DC Buff W 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1998,45(3):537-538
This paper presents the design and measurement of a SAW device to be used in a correlator receiver for a differential phase shift keying direct sequence spread spectrum (DPSK/DSSS) system. The DPSK modulation format allows noncoherent data demodulation while the SAW device correlator acts as the despreading operator. In a conventional DPSK receiver, the received signal is normally split into a lower and upper path. One of the paths contains a correlator, and the other path contains a one data bit delay element and another correlator. The outputs of both paths are then fed to a noncoherent data demodulator. The device presented in this paper combines both the delay element and the two correlators in a single SAW device; therefore, a better temperature tracking mechanism, simplicity, as well as the elimination of the broadband SAW delay line are achieved. The SAW structure contains a broadband SAW transducer, and two serially coded pseudo noise (PN) DPSK filters. The SAW based correlator was built on lithium tantalate. The center frequency was set to 150 MHz, with a 63 chip PN spreading code and a data rate of 300 Kbps. Experimental measurements of the SAW device autocorrelation results are presented. 相似文献
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Nomura T Takebayashi R Saitoh A 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1998,45(5):1261-1265
A one-port surface acoustic wave (SAW) resonators incorporating Langmuir-Blodgett (LB) films has been investigated. SAW sensors are one potential applications of SAW devices. Most of the work reported on SAW sensor concerns delay lines. In this paper we characterize the mass loading effects of one-port resonators by depositing successive monolayers of LB films onto the surface. A 90 MHz SAW gas-phase sensor has been fabricated on an ST cut quartz substrate, and one-port resonator configurations have been used as the sensing element. Ultra thin monolayers of arachidic acid and arachidic acid ethyl ester have been deposited using the LB method. The resonant frequencies and the Q values have been measured as sensor response. Experimental results show that the Q values and the resonant frequencies of the one-port SAW resonator vary with film mass loading on the SAW device surface. 相似文献
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介绍了一种遥测声表面波压力传感器的原理与设计,其核心敏感部件是由声表面波谐振器组成的振荡器,文中给出了主要的测试结果。 相似文献