Influence of electrical boundary conditions on profiles of acoustic field and electric potential of shear-horizontal acoustic waves in potassium niobate plates

Backward Acoustic Waves in Piezoelectric Plates: Possible Application as Base for Liquid Sensors

“…An analysis of the results obtained has shown that in the frequency range of 3–8 MHz, there are two acoustic waves of the first order and these are shear-horizontal SH 1 and antisymmetric A 1 waves [ 29 , 30 , 32 ]. It is possible to see that the presence of a non-viscous and non-conductive liquid on the surface of a piezoelectric plate does not change the frequency of the backward acoustic wave but significantly reduces its amplitude.…”

“…Devices based on the negative refraction of elastic-guided waves were suggested recently [ 31 ]. It was also theoretically shown that the properties of these waves depend on the electrical boundary conditions on the surface of the piezoelectric plate [ 32 ]. A method for the detection of backward acoustic waves in piezoelectric plates using a set of interdigital transducers with different wavelengths was developed recently [ 29 , 33 ].…”

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

“…It is well-known that a change in electric conductivity of an adjacent medium located on a surface of a piezoelectric substrate produces a change in phase velocity and attenuation of any acoustic wave with nonzero coupling constant (Rayleigh [ 1 , 2 , 3 ], Love [ 3 ], Lamb [ 4 , 5 ], zero-order shear-horizontal [ 6 , 7 ], higher-order [ 8 ], slot [ 9 , 10 ], etc.). For most waves, the phase velocity decreases with conductivity monotonically, approaching its minimum value when tangential components of electric fields accompanying the wave are completely shorted [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ].…”

“…It is well-known that a change in electric conductivity of an adjacent medium located on a surface of a piezoelectric substrate produces a change in phase velocity and attenuation of any acoustic wave with nonzero coupling constant (Rayleigh [ 1 , 2 , 3 ], Love [ 3 ], Lamb [ 4 , 5 ], zero-order shear-horizontal [ 6 , 7 ], higher-order [ 8 ], slot [ 9 , 10 ], etc.). For most waves, the phase velocity decreases with conductivity monotonically, approaching its minimum value when tangential components of electric fields accompanying the wave are completely shorted [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. On the other hand, for particular cases of slightly inhomogeneous piezoactive surface acoustic waves with shear-horizontal polarization (Bleustein-Gulyaev and/or Love waves), an increase in conductivity of a substrate or conductive layer deposited on the substrate produces, first, an increase in phase velocity of the wave until some maximal value and then, a decrease in the velocity to some minimal value [ 11 , 12 ].…”

“…The acoustoelectric attenuation behaves similar for all types of acoustic waves: it increases for small conductivities, approaches some maximum for intermediate conductivities, and decreases to zero for large conductivities of the substrate or layer [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. This property is due to the fact that at low conductivities, the layer behaves like dielectric, while at high conductivities it is more like an ideal conductor.…”