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Numerical Analysis of a Tunable Rectangular Patch Antenna with One Tuning Post

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Journal of Modern Transportation 1998年第1期15卷 71-76页

作者：刘运林杨儒贵任朗

The finite element method(FEM) is applied to a thin substrate rectangular antenna with a shorting post. The results of the resonant frequencies are in good agreement with the experimental data. The input impedances are calculated and the results are presented. In principle, this method is applicable to a microstrip antenna with shorting posts in arbitrary locations.

关键词： rectangular patch antenna resonant frequency impedance shorting post FEM

A hybrid magnetostrictive-piezoelectric barrel-stave projector

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Chinese Journal of Acoustics 2006年第4期25卷 371-377页

作者： CHAI Yong MO Xiping LIU Yongping CUI Zheng Institute of Acoustics Chinese Academy of Sciences Beijing 100080 Graduate School of the Chinese Academy of Sciences Beijing 100029

A hybrid magnetostrictive-piezoelectric barrel-stave projector is designed and developed. The new type transducer is driven by the union of rare-earth giant magnetostrictive material Terfenol-D and PZT piezoelectric ceramic. Combining the advantages of low frequency performance within a compact size, it proves that the hybrid projector has a much broader band and higher sound power than that with single magnetostrictive or piezoelectric driver by the simulated and measured results. The prototype of the hybrid projector has a size of 88 mm in outside diameter and 316 mm in length, with an underwater resonant frequency of 1.30 kHz, Q factor of 1.43 for -3 dB bandwidth, and transmitting voltage response level of 135.1 dB at the resonant frequency.

关键词： resonant frequency giant magnetostrictive piezoelectric ceramic low frequency sound power the union new type

Study on rectangular ultrasonic radiator of flexural resonant vibration in high modes

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Chinese Journal of Acoustics 1993年第4期12卷 326-334页

Based on the theory of coupling vibration and flexural vibration of thin rod of rectangular cross section, the flexural vibration of rectangular thin plate was studied. The frequency equation was derived under the condition of free boundaries. The normal modes and the relation between the normal modes and the resonant frequency were obtained. Experiments showed that the calculated resonant frequencies agree well with the measured results, and the rectangular thin plate in flexural vibration has abundant resonant frequencies. The radiator of flexural vibration used in ultrasonic cleaning and other techniques has the advantages of large acoustic radiating area, uniform acoustic field and easy adjustment of resonant frequencies, proving that it is a promising ultrasonic source.

关键词： Flexural vibration resonant frequency Coupling vibration Ultrasonic radiator.

Nonlinear Vibration of an Embedded Carbon Nanotube in a Polymer Matrix

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Nonlinear Vibration of an Embedded Carbon Nanotube in a Poly...

第18届国际真空大会

作者： M. H. Mahdavi Department of Mechanical and Materials Engineering The University of Western Ontario London ON N6A 5B9 Canada

Since the discovery of carbon nanotubes （CNTs）, these novel materials have attracted considerable attentions from research community. CNTs are found to possess superior mechanical, electronic and thermal properties. These extraordinary physical properties make CNTs hold promise for potential applications as nanodevices and nanocomposites. For the application and design of these nanocomposites, it is essential to investigate the effect of polymer matrix on the vibrational behavior of the embedded CNTs. In the current work, the effect of the surrounding medium on the CNT is described by van der Waals （vdW） forces. The intrinsic nonlinearity of vdW forces will arouse the nonlinear vibration of CNTs. Thus, the resonant frequencies of CNT are deflection dependent. Using both Euler-Bernoulli and Timoshenko beam models, the relation between deflection amplitudes and resonant frequencies of CNT is derived through harmonic balance method according to different end conditions. It is found that the end conditions, cross-sectional dimension and length of the embedded CNT have a significant effect on the resonant frequencies. It is also found that the applicability and the accuracy of Euler-Bernoulli and Timoshenko beam models are influenced by the surrounding medium. For double-walled CNTs embedded in the polymer matrix, another source for nonlinear vibration comes from the nonlinear vdW interactions between tubes. This interlayer vdW forces results in both coaxial and non-coaxial vibrations of the CNTs. The vibration amplitude for the non-coaxial mode is more dependent on the frequency in contrast to the coaxial mode. It is also found that the surrounding matrix has a significant effect on resonant frequency of the coaxial mode, but not on the non-coaxial mode.

关键词： carbon nanotube nanocomposites nonlinear vibration resonant frequency van der Waals forces.

Investigating The Influence on Resonance frequency with Aspect Ratio of 1-3 Piezocomposites

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Investigating The Influence on Resonance Frequency with Aspe...

第二届全国压电和声波理论及器件技术研讨会

作者： Li Li~1,Lei Qin~2,Likun Wang~2,Yuanyuan Wan~2,Hongliang Du~2,Baisheng Sun~2 (1.Beijing University of Posts and Telecommunications,Beijing 100876,P.R.China 2.Beijing Information technology Institute,Beijing 100101,P.R.China)

The influence of aspect ratio(width/height of shape and pillar) on resonance frequency of 1-3 and 1-3-2 type piezoelectric composites has been investigated.1-3 and 1-3-2 composite samples were fabricated by dice-fill *** geometric size was tailored by dicing samples,and the width/height ratio of ceramic pillar was altered by adjusting the height of ***,performance of composites(the resonant frequency and electromechanical coupling coefficient) was *** result showed that the resonant frequency has been affected by the variety of geometries of *** lateral resonant frequency and frequency of Lamb wave were increased with diminishment of sample *** thickness resonant frequency was increasing when the width/height of pillar diminished.

关键词： Piezoelectric composite Aspect ratio resonant frequency

EFFECTS OF A VISCOUS AND CONDUCTIVE LIQUID ON THICKNESS SHEAR VIBRATION OF ZnO FILMS WITH TILTED C-AXIS ORIENTATION

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EFFECTS OF A VISCOUS AND CONDUCTIVE LIQUID ON THICKNESS SHEA...

2015全国压电和声波理论及器件技术研讨会

作者： Xian FU Jian-ke DU Jia LOU Ji WANG Ting-feng MA Bin HUANG Li-wen HE School of Mechanical Engineering and Mechanics Ningbo University

The thickness-shear vibration of c-axis tilted 43°ZnO thin film,one side of it is contacted with a layer of viscous conducti ve liquids is *** frequency equation has been derived from the three-dimensional linear piezoelectricity *** effects of conductivity on the shift in the resonant frequency has been analyzed and discussed in *** setting the density,the viscous coefficient and the thickness of the liquid as specified values,the relation of the shift in the resonant frequency and the conductivity is *** present results demonstrate that the shift in the resonant frequency decreases with the conductivity in a special *** method and calculation results can provide important reference to the resonators design.

关键词： resonant frequency Viscous and conductive liquid Thickness shear vibration ZnO thin film

THE MAGNETOELECTRIC EFFECTS OF TERFENOL-D/PZT/TERFENOL-D LAMINATED STRUCTURES

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THE MAGNETOELECTRIC EFFECTS OF TERFENOL-D/PZT/TERFENOL-D LAM...

2012全国压电和声波理论及器件技术研讨会

作者： Long XIA Jian-ke DU Ji WANG Department of Engineering Mechanics Ningbo University

Magnetoelectric（ME） laminated materials,especially laminate ME composites made by combining magnetostrictive and piezoelectric layers,exhibit excellent ME effect,and meet the demands of practical application for sensors,transducers *** laminate ME composites,the ME effect is derived from the coupling between a magnetostrictive effect in the magnetostrictive layers and a piezoelectric effect in the piezoelectric *** Magnetoelectric material of Terfenol-D/PZT/Terfenol-D（MPM） can be used as a type of magnetoelectric *** paper investigates the magnetoelectric effects of laminated piezomagnetic/piezoelectric structures by means of *** a proper biasing magnetic field and a drive magnetic field of proper frequency the laminated structures exert the better magnetoelectric *** can be found that in a bias magnetic field of 300-400 Oe and an alternating magnetic field of 1Oe,the peak of magnetoelectric voltage conversion coefficient of resonant frequency is 613.7mV/*** for the laminated structure used in the test.

关键词： Magnetoelectric Biasing magnetic field resonant frequency

NUMERICAL ANALYSES ON THE SANDWICH DIPOLE LOGGING TRANSDUCER WITH VARIOUS LOADS

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NUMERICAL ANALYSES ON THE SANDWICH DIPOLE LOGGING TRANSDUCER...

2012全国压电和声波理论及器件技术研讨会

作者： Qiu-ying CHEN Jian-sheng CONG Xiao-min WANG Xiu-ming WANG State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of Sciences

Numerical modeling for a sandwich dipole well logging transmitting transducer is conducted in this *** characteristics for the first-order bending vibration of the sandwich transducer within different fluid loads are numerically *** is found that the resonant frequency and transmitting voltage response level are affected by the density,acoustic velocity and acoustic impedance of the fluid *** numerical results were preliminarily vahdated by our *** numerical analyses may provide useful suggestion for both the simulation design of logging transducer and the acoustic logging applications.

关键词： Bending vibration mode Load resonant frequency Transmitting voltage response

Simulation and fabrication of the SiC-based clamped-clamped filter

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Simulation and fabrication of the SiC-based clamped-clamped ...

2008 9th International Conference on Solid-State and Integrated-Circuit Technology

作者： Yongmei Zhao*1 2 Jin Ning1 Guosheng Sun1 2 Xingfang Liu1 2 Liang Wang1 2 Gang Ji2 Lei Wang2 Wanshun Zhao2 Jinmin Li2 and Fuhua Yang1 1 State Key Laboratories of Transducer Technology Institute of Semiconductors Chinese Academy of Sciences Beijing100083 P. R. China 2 Key Laboratory of Semiconductor Materials Science Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 P. R. China State Key Laboratories of Transducer Technology Institute of SemiconductorsChinese Academy of Sciences Key Laboratory of Semiconductor Materials Science Institute of SemiconductorsChinese Academy of Sciences

In this paper, the SiC-based clamped-clamped filter was designed and fabricated. The filter was composed of two clamped-clamped beam micromechanical resonators coupled by a spring coupling beam. Structural geometries, including the length and width of the resonator beam and coupling beam, were optimized by simulation for high frequency and high Q, under the material properties of SiC. The vibrating modes for the designed filter structure were analyzed by finite element analysis （FEA） method. For the optimized structure, the geometries of resonator beams and coupling beams, as well as the coupling position, the SiC-based clamped-clamped filter was fabricated by surface micromaching technology.

关键词： [IEEE Keyword]Geometry Bandwidth resonant frequency Band pass filters Filtering theory Couplings Resonator filters