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Longitudinal modes along thin piezoelectric waveguides for liquid sensing applications.

Caliendo C - Sensors (Basel) (2015)

Bottom Line: The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction.Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface.Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example.

View Article: PubMed Central - PubMed

Affiliation: Istituto di Acustica e Sensori O. M. Corbino, IDASC-CNR, Via del Fosso del Cavaliere 100, 00133 Roma, Italy. cinzia.caliendo@idasc.cnr.it.

ABSTRACT
The propagation of longitudinally polarized acoustic modes along thin piezoelectric plates (BN, ZnO, InN, AlN and GaN) is theoretically studied, aiming at the design of high frequency electroacoustic devices suitable for work in liquid environments. The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction. Such waves are suitable for the implementation of high-frequency, low-loss electroacoustic devices operating in liquid environments. The time-averaged power flow density, the phase velocity and the electroacoustic coupling coefficient K2 dispersion curves were studied, for the first (S0) and four higher order (S1, S2, S3, S4) symmetrical modes for different electrical boundary conditions. Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface. Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example. The relative velocity changes, and the inertial and viscous sensitivities of the first symmetric and anti-symmetric mode, S0 and A0, propagating along thin plates bordered by a viscous liquid were derived using the perturbation approach. The present study highlights the feasibility of the piezoelectric waveguides to the development of high-frequency, integrated-circuits compatible electroacoustic devices suitable for working in liquid environment.

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Phase and group velocity, and K2 dispersion curves of the A0 mode propagating along the MST and ST configurations on GaN plate.
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sensors-15-12841-f011: Phase and group velocity, and K2 dispersion curves of the A0 mode propagating along the MST and ST configurations on GaN plate.

Mentions: The phase and group velocity, and K2 dispersion curves of the A0 mode travelling along the GaN plate are shown in Figure 11, for the two coupling configurations. The horizontal green line crosses the A0 phase velocity curve at 1480 m/s for h/λ = 0.12: the corresponding K2 values are 0.35% and 0.06% for the ST and MST structures, as shown by the dotted green arrow.


Longitudinal modes along thin piezoelectric waveguides for liquid sensing applications.

Caliendo C - Sensors (Basel) (2015)

Phase and group velocity, and K2 dispersion curves of the A0 mode propagating along the MST and ST configurations on GaN plate.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507606&req=5

sensors-15-12841-f011: Phase and group velocity, and K2 dispersion curves of the A0 mode propagating along the MST and ST configurations on GaN plate.
Mentions: The phase and group velocity, and K2 dispersion curves of the A0 mode travelling along the GaN plate are shown in Figure 11, for the two coupling configurations. The horizontal green line crosses the A0 phase velocity curve at 1480 m/s for h/λ = 0.12: the corresponding K2 values are 0.35% and 0.06% for the ST and MST structures, as shown by the dotted green arrow.

Bottom Line: The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction.Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface.Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example.

View Article: PubMed Central - PubMed

Affiliation: Istituto di Acustica e Sensori O. M. Corbino, IDASC-CNR, Via del Fosso del Cavaliere 100, 00133 Roma, Italy. cinzia.caliendo@idasc.cnr.it.

ABSTRACT
The propagation of longitudinally polarized acoustic modes along thin piezoelectric plates (BN, ZnO, InN, AlN and GaN) is theoretically studied, aiming at the design of high frequency electroacoustic devices suitable for work in liquid environments. The investigation of the acoustic field profile across the plate revealed the presence of longitudinally polarized Lamb modes, travelling at velocities close to that of the longitudinal bulk acoustic wave propagating in the same direction. Such waves are suitable for the implementation of high-frequency, low-loss electroacoustic devices operating in liquid environments. The time-averaged power flow density, the phase velocity and the electroacoustic coupling coefficient K2 dispersion curves were studied, for the first (S0) and four higher order (S1, S2, S3, S4) symmetrical modes for different electrical boundary conditions. Two electroacoustic coupling configurations were investigated, based on interdigitated transducers, with or without a metal floating electrode at the opposite plate surface. Enhanced performances, such as a K2 as high as 8.5% and a phase velocity as high as 16,700 m/s, were demostrated for the ZnO- and BN-based waveguides, as an example. The relative velocity changes, and the inertial and viscous sensitivities of the first symmetric and anti-symmetric mode, S0 and A0, propagating along thin plates bordered by a viscous liquid were derived using the perturbation approach. The present study highlights the feasibility of the piezoelectric waveguides to the development of high-frequency, integrated-circuits compatible electroacoustic devices suitable for working in liquid environment.

Show MeSH
Related in: MedlinePlus