Quasi-Linear Polarized Modes in Y-Rotated Piezoelectric GaPO4 Plates

It is shown that, in spite of the wave radiation into the adjacent liquid, a large group of Lamb waves are able to propagate along piezoelectric plates (quartz, LiNbO3, LiTaO3) coated with a liquid layer (distilled water H2O). When the layer freezes, most of the group’s waves increase their losses, essentially forming an acoustic response towards water-to-ice transformation. Partial contributions to the responses originating from wave propagation, electro-mechanical transduction, and wave scattering were estimated and compared with the coupling constants, and the vertical displacements of the waves were calculated numerically at the water–plate and ice–plate interfaces. The maximum values of the responses (20–30 dB at 10–100 MHz) are attributed to the total water-to-ice transformation. Time variations in the responses at intermediate temperatures were interpreted in terms of a two-phase system containing both water and ice simultaneously. The results of the paper may turn out to be useful for some applications where the control of ice formation is an important problem (aircraft wings, ship bodies, car roads, etc.).

Section: Introductionmentioning

confidence: 99%

An Analysis of the Water-to-Ice Phase Transition Using Acoustic Plate Waves

Анисимкин

Kolesov

Kuznetsova

et al. 2021

“…The waves of this type are characterized by the largest electromechanical coupling coefficients among all other waves in the same materials [ 7 , 13 , 18 ]. Furthermore, the spectrum of higher-order waves in piezoelectric plates with a thickness comparable to or greater than the wavelength is very wide and the number and properties of the plate waves are purposefully varied by the plate thickness h , wavelength λ , mode order n , and propagation direction [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Electric fields of the modes penetrate into contacting liquid and interact with free charge carriers.…”

Section: Introductionmentioning

confidence: 99%

Multimode Design and Piezoelectric Substrate Anisotropy Use to Improve Performance of Acoustic Liquid Sensors

Smirnov

Анисимкин

Воронова³

et al. 2022

Using acoustic wave modes propagation in piezoelectric plates loaded with conductive liquids, peculiarities of the mode-liquid acoustoelectric interaction are studied. It is found that (i) in contrast to bulk and surface acoustic waves propagating in piezoelectric semiconductors, the acoustoelectric attenuation of the modes is not symmetric in respect to its maximum, (ii) a large increase in attenuation may be accompanied by a small decrease in phase velocity and vice versa, (iii) the peculiarities are valid for “pure” (without beam steering) and “not pure” (with beam steering) modes, as well as for modes of different orders and polarizations, and (iv) conductivity of test liquid increases electromagnetic leakage between input and output transducers, affecting results of the measurements. To decrease the leakage, the liquid should be localized between transducers, outside the zone over them. If so, the mode sensitivity may be as large as 8.6 dB/(S/m) for amplitude and 107°/(S/m) for phase. However, because of comparable cross-sensitivity towards viscosity and dielectric permittivity, modes with selective detection of liquid conductivity are not found.

“…These cases include the linearly-polarized modes, such as the longitudinally-polarized Anisimkin Jr. modes (AMs), with a dominant longitudinal displacement component U 1 with a constant amplitude along the whole depth of the plate, the shear components, U 2 and U 3 , being at least 10-times less than U 1 at any plate depth. AMs were first discovered in quartz plates [ 1 ] and then in LiNbO 3 , Te [ 2 ], LiTaO 3 , Ba 2 NaNb 5 O 15 , KH 2 PO 4 , Li 2 B 4 O 7 , TeO 2 , PbMoO 4 , KH 2 PO 4 and ZnO [ 3 , 4 ] and, recently, in GaPO 4 [ 5 ]. The AMs, while having a phase velocity close to that of the longitudinal bulk acoustic wave (LBAW) traveling in the same direction, can be suitable for the development of high-frequency electroacoustic devices if implemented on fast materials, such as BN and AlN.…”

Section: Introductionmentioning

confidence: 99%

Analytical Study of the Propagation of Fast Longitudinal Modes along wz-BN/AlN Thin Acoustic Waveguides

Caliendo

2015

Self Cite

The propagation of the fundamental symmetric Lamb mode S0 along wz-BN/AlN thin composite plates suitable for telecommunication and sensing applications is studied. The investigation of the acoustic field profile across the plate thickness revealed the presence of modes having longitudinal polarization, the Anisimkin Jr. plate modes (AMs), travelling at a phase velocity close to that of the wz-BN longitudinal bulk acoustic wave propagating in the same direction. The study of the S0 mode phase velocity and coupling coefficient (K2) dispersion curves, for different electrical boundary conditions, has shown that eight different coupling configurations are allowable that exhibit a K2 as high as about 4% and very high phase velocity (up to about 16,700 m/s). The effect of the thickness and material type of the metal floating electrode on the K2 dispersion curves has also been investigated, specifically addressing the design of an enhanced coupling device. The gravimetric sensitivity of the BN/AlN-based acoustic waveguides was then calculated for both the AMs and elliptically polarized S0 modes; the AM-based sensor velocity and attenuation shifts due to the viscosity of a surrounding liquid was theoretically predicted. The performed investigation suggests that wz-BN/AlN is a very promising substrate material suitable for developing GHz band devices with enhanced electroacoustic coupling efficiency and suitable for application in telecommunications and sensing fields.