Analysis of the Excitation and Detection of Piezoelectric Surface Waves in Quartz by Means of Surface Electrodes

Abstract

The power extracted from a piezoelectric surface wave in quartz by an arrangement of electrodes on the surface is determined by a perturbation technique, which is extremely accurate for low-coupling materials. The mechanical portion of the surface wave is found by neglecting the piezoelectric coupling, which is very small in quartz. The elastic solution then yields both volumetric and surface source terms, which are generated by the piezoelectric coupling and drive the steady-state electrostatic solution. A technique is introduced for reducing the remaining electrostatic problem to Laplace's equation, subject to such boundary conditions that the solution is amenable to conformal mapping techniques for several interesting, and possibly useful, electrode arrangements. Surface waves propagating along the digonal axis for all rotated Y cuts are considered, as well as those propagating in all directions along the surface of an X-cut crystal. A reciprocal relation between the excitation and detection problems is derived, and is used to determine the amplitude of a surface wave generated by the application of an alternating voltage to the surface electrodes when the solution to the detection problem for the same arrangement of electrodes is known.

A planar surface acoustic wave micropump for closed-loop microfluidics

“…Longer wavelength devices suffer from decreased electrode efficiency and increased mass loading, 35,36 whereas the steep roll-off at shorter wavelengths arises from increased absorption within the PDMS channel wall [analogous to increased coupling into the overlaid material, similar to that observed in Fig. 2(a) for water].…”

Propagation Characteristics of Surface Waves in Quartz and Their Influence on Device Performance

“…(1)-(3) reveals that in the presence of a linear, homogeneous bias, the surface wave propagation characteristics can be obtained in a straightforward manner from the solution of the boundary value problem defined by Eqs. (1) and (3). This solution indicates a nondispersive wave propagation but with a change in the natural velocity as well as the polarization vector of the surface wave.…”

“…Again, it should be noted that eLvQa has lower symmetry than cLyQa as is the case with GLyQa. Furthermore, if the propagating medium is subject to a temperature variation, the corresponding change in the fundamental elastic constants must be accounted for by hcpyQa which takes the form The surface wave solution in an arbitrarily anisotropic and piezoelectric solid is well-known [1,23,24] and may be written in the form…”

“…When referred to the reference (or undeformed) coordinate axes fixed to the solid, the equations of motion in presence of a static bias may be written in the form (1) where GLyQa is the effective elastic constant, ua is the dynamic displacement vector and po is the mass density in the reference state. In Eq.…”

Applications of Piezoelectric Materials in Structural Health Monitoring and Repair: Selected Research Examples

“…The difficulties of the analyses lie in the full electromechanical coupling in the structure. Tseng [98], Coquin and Tierstan [99], and Joshin and White [100] analyzed this problem by solving an electrostatic problem, and substituted the distribution of the electric fields into the electromechanical coupled equation, hence obtaining the secondary electric fields and the distribution of displacement fields. In a monograph of Parton et al [91], the analytical solutions for an IDT which generates Rayleigh surface waves in a hexagonal 6 mm piezoelectric medium were presented based on the same procedure.…”