Elastic Surface Wave Guidance by (Δ<i>v/v</i>) Effect Guidance Structures

Hughes, A. J.

doi:10.1063/1.1661562

Cited by 27 publications

(4 citation statements)

References 16 publications

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“…However, as the guided wave propagates, the transverse width of most shorting-strip waveguides is constant and if the wave is able to be initially confined it should remain confined. Hughes (1972) simply assumed the open-to-short circuit wave velocity difference ∆v to be the dominant factor in guiding SAW within the shorting strip. His theoretical work-adopting an isotropic mode which incorporated the velocity difference-adequately predicted the major features of this kind of guiding structure: strong guidance and low dispersion for many common piezoelectric materials (e.g., LN).…”

Section: Shorting-strip Waveguidesmentioning

confidence: 99%

A review: controlling the propagation of surface acoustic waves via waveguides for potential use in acoustofluidics

Mei

Friend

2020

Mechanical Engineering Reviews

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This paper presents a review of waveguides on lithium niobate for surface acoustic waves (SAWs), including in particular the classic literature on the topic with the intent of renewing interest in them in the context of potential applications in the burgeoning discipline of micro to nano-scale acoustofluidics. From the fundamentals of the piezoelectric effect we describe interdigital electrodes and how they generate acoustic waves, consider focusing interdigital electrodes as a simple means of laterally confining the acoustic energy propagating across a substrate, and then quickly move to waveguiding structures that provide confinement by defining either a region of slow wave velocity or a physically isolated structure. The ability to steer acoustic waves using these waveguides is considered. The many analytical, computational, and experimental tools devised by past investigators to design them are discussed in detail, as are the relative advantages and disadvantages of the waveguide designs considered over the years.The most popular materials that are used to make SAW devices include quartz, lithium tantalate (LT) LiTaO 3 and lithium niobate (LN) LiNbO 3 . Others include gallium arsenide (GaAs), cadmium sulfide (CdS), zinc oxide (ZnO), lithium tetraborate (Li 2 B 4 O 7 ), and lanthanum gallium silicate (La 3 Ga 5 SiO 12 ) (Thurston et al., 1998). Due to the crystalline structure of these materials, the type of wave generated is strongly dependent on the choice and orientation of the material as discussed above. Lithium niobate has been the preferred material for devices requiring high efficiency, as it possesses a relatively large electromechanical coupling coefficient open-circuit) and v m is the SAW velocity along a short-circuited surface. Of the various cuts possible, the 131 • Y-rotated cut for X-propagating SAW in LN was found to have the highest electromechanical coupling coefficient for SAW (Slobodnik et al., 1970), relative to other cuts in LN and other choices of single-crystal piezoelectric media. In 1976, Shibayama et al. conducted experiments to determine the optimum rotated Y-cut of LN to generate "true" SAWs and concluded that the 127.86 • Y-rotated choice for X-propagating SAW in lithium niobate (128 • YX LN) reduced the generation of other parasitic waves and retained most of the electromechanical coupling and low insertion loss observed in the 131 • Y-rotated cut of LN. Generating SAW on lithium niobateInterdigital transducers are one of the most widely used devices that generate and detect SAWs. The first and simplest IDTs (White et al., 1965) consisted of straight rectangular metal bars-fingers-deposited on the surface of a piezoelectric substrate. Alternately connected on their end to common electrodes or bus bars, the fingers appear as depicted in Fig. 1. An array of electric fields of alternating direction is created between the transducer finger pairs, and thus in turn induces alternating regions of compression and tension in the substrate. Each finger pair therefore produces displacemen...

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Section: Shorting-strip Waveguidesmentioning

confidence: 99%

A review: controlling the propagation of surface acoustic waves via waveguides for potential use in acoustofluidics

Mei

Friend

2020

Mechanical Engineering Reviews

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“…For instance, P (x, y) = e ikr cos(ϕ−ϑ) (17) with a complex ϑ . Rayleigh waves of this type on isotropic homogeneous half-space have earlier been considered in [6]. Differentiating (17) with respect to ϕ yields solutions with polynomial amplitudes, analogous to (8)-(10).…”

Section: Inhomogeneous Plane Waves With Polynomial Amplitudesmentioning

confidence: 99%

Novel exact surface wave solutions for layered structures

Kiselev

Ducasse

Deschamps

et al. 2007

Comptes Rendus. Mécanique

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Novel exact solutions describing surface acoustic waves on general layered structures have been found by the method of variable separation. First, solutions have been constructed with plane wavefronts and involving polynomial dependence on lateral variables. Second, their inhomogeneous plane-wave analogues have been found. At last, beam-like solutions highly localized at large lateral distances in a given sector have also been considered.

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“…J-00 Jn-Piii (5) in which 0 is the central angle for the output i.d.t. The summation in the denominator is carried out only for propagating modes.…”

Section: Losses Due To Mode Conversion and Nonuniform Irradiationmentioning

confidence: 99%

Waveguide-type s.a.w. filter using energy focusing interdigital transducers

Yamaguchi

Temma

Kogo

1979

IEE J. Microw. Opt. Acoust. UK

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The paper deals with a surface-acoustic-wave filter using a Au/u-waveguide and energy focusing interdigital transducers. The losses and the frequency response of the filter were analysed theoretically and were compared with experimental results performed on yZ-LiNbO 3 . In addition, it is shown both experimentally and theoretically how the waveguide length affects filter performances. The use of a waveguide and energy focusing transducers is effective in s.a.w. filters in which the input and output transducers can be arbitrary-overlap weighted independently, and the insertion loss is comparable to that for conventional s.a.w. filters. The results obtained in the paper are also effectively used in designing many of the practical s.a.w. devices employing waveguides.

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Elastic Surface Wave Guidance by (Δv/v) Effect Guidance Structures

Cited by 27 publications

References 16 publications

A review: controlling the propagation of surface acoustic waves via waveguides for potential use in acoustofluidics

A review: controlling the propagation of surface acoustic waves via waveguides for potential use in acoustofluidics

Novel exact surface wave solutions for layered structures

Waveguide-type s.a.w. filter using energy focusing interdigital transducers

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