Shear Mode Piezoelectric Thin Film Resonators

Yanagitani, Takahiko

doi:10.5772/18797

Cited by 5 publications

(3 citation statements)

References 48 publications

(53 reference statements)

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“…The displacement direction is not perpendicular to the propagation direction, i.e., it is not parallel to the surface, but has a certain deviation angle. 6,7 In the films with the c-axis tilt corresponding to maximum of the coupling coefficient the angle between the wave propagation direction and displacement motion is, approximately, 85 . 7 Since liquids exhibit isotropic elastic properties, the quasi-shear thickness mode degenerates at the liquid interface into pure shear and longitudinal components.…”

Section: Introductionmentioning

confidence: 99%

“…6,7 In the films with the c-axis tilt corresponding to maximum of the coupling coefficient the angle between the wave propagation direction and displacement motion is, approximately, 85 . 7 Since liquids exhibit isotropic elastic properties, the quasi-shear thickness mode degenerates at the liquid interface into pure shear and longitudinal components. 6,7 The longitudinal component emits compressional waves into the liquid, which breaks the condition of the laminar flow at the interface ( Fig.…”

Section: Introductionmentioning

confidence: 99%

“…7 Since liquids exhibit isotropic elastic properties, the quasi-shear thickness mode degenerates at the liquid interface into pure shear and longitudinal components. 6,7 The longitudinal component emits compressional waves into the liquid, which breaks the condition of the laminar flow at the interface ( Fig. 1(a)).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ferroelectric film bulk acoustic wave resonators for liquid viscosity sensing

Vorobiev

Gevorgian

2013

Journal of Applied Physics

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A concept of accurate liquid viscosity sensing, using bulk acoustic wave (BAW) resonators, is proposed. The proposed BAW resonators use thin ferroelectric films with the dc field induced piezoelectric effect allowing for generation of pure longitudinal acoustic waves in the thickness excitation mode. This makes it possible to utilize exclusively shear liquid particle displacement at the resonator side walls and, therefore, accurate viscosity evaluation. The BAW resonators with the dc field induced piezoelectric effect in 0.67BiFeO 3-0.33BaTiO 3 ferroelectric films are fabricated and their liquid viscosity sensing properties are characterized. The resonator response is analyzed using simple model of a harmonic oscillator damped by a viscous force. It is shown that the resonator Q-factor is inversely proportional to the square root of the viscosity-density product. The viscosity measurement resolution is estimated to be as high as 0.005 mPaÁs, which is 0.5% of the water viscosity. V

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ferroelectric film bulk acoustic wave resonators for liquid viscosity sensing

Vorobiev

Gevorgian

2013

Journal of Applied Physics

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A method for extracting sole mechanical properties of Bragg reflector by GHz ultrasonic pulse-echo technique

Yanagitani

Ishii

Kondo

et al. 2022

Applied Physics Letters

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Solidly mounted resonators (SMRs) with an acoustic Bragg reflector should be more suitable for high power RF filters than a self-standing structure because heat can be transferred to the supporting substrate. Thus, even though the demand for SMRs is expected to increase, the evaluation of the properties of the Bragg reflector that comprise them cannot be separated from the properties of the resonator as a whole. A method to evaluate the mechanical reflection coefficient of the Bragg reflector alone before the piezoelectric layer is grown would, therefore, be attractive, as it would be useful in optimizing the Bragg reflector. In this study, a nondestructive evaluation method of the reflector using a GHz ultrasonic pulse-echo technique is proposed. The Sc0.40Al0.60N film ultrasonic transducers with electromechanical coupling coefficient kt2 of 15.8% and longitudinal wave insertion loss of 7.0 dB with 77% fractional bandwidth were employed for the measurement system. Mo/SiO2 Bragg reflector test samples with various number of pairs were evaluated. The experimental mechanical reflectance of the Bragg reflector agreed well with theoretical results simulated by a mechanical equivalent circuit model.

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