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First results of numerical and physical experiments for the ring waveguide resonator on surface acoustic waves are presented. The structure consists of a gold interdigital transducer in the form of a ring placed on the Z cut of aluminum nitride crystal. Excitation of radial modes is investigated. The electrical admittance frequency dependence of such resonator does not have sidelobes. A high quality factor is achievable.

Analysis of second-harmonic generation of Lamb modes using a modal analysis approach J. Appl. Phys. 94, 4152 (2003) Nonlinear surface acoustic wave pulses in solids: Laser excitation, propagation, interactions (invited) Rev. Sci. Instrum. 74, 448 (2003) Dynamic higher-order correction of acoustic aberration due to material microstructure Appl. Phys. Lett. 81, 2288Lett. 81, (2002 Modal analysis of second-harmonic generation of shear horizontal modes in an elastic plate A method for determining surface impedances of periodic structures is proposed. The method is based on Biryukov's equation for the surface impedance matrix of an inhomogeneous medium. This nonlinear integro-differential equation relates the impedance matrix with material parameter distributions. A solution of such equation is an alternative approach to boundary-value problems in contrast to the known finite element method. It is demonstrated that this equation in the case of periodic structures is reduced to a system of nonlinear ordinary differential equations of the first order in partial impedances. The developed impedance method is applied to a complex periodic system of elastic electrodes placed on a piezoelectric substrate. By analogy with the well-known function of surface effective permittivity, the infinite matrix of effective permittivity is introduced in an explicit form to characterize the piezoelectric substrate surface loaded by elastic strips. Due to this approach the known complex electromechanical boundary-value problem for calculation of interdigital transducers of surface acoustic waves is reduced to a pure electrical boundary-value problem. Then this last problem is solved by methods of electrostatics in the general case of arbitrary number of different electrodes per periodic cell. As a result, the electrical admittance matrix elements, relating electrode currents with voltages, are obtained. These elements are represented as ratios of dispersion equations' left-hand side corresponding to various electrode connections. As examples, the frequency dependence of electrical admittances for some important multielectrode periodic cells are calculated.

In the present paper three mechanisms of self-polarization of ferroelectric crystals are discussed: polarization by the crystal bending, that by the “organized” Phase transition and that by the internal field. It is shown that these mechanisms operate also in the case of films. However, the using of cathode sputtering leads to the appearance of two new mechanisms: polarization by the field biasing the substrate with respect to the gas discharge at the film deposition temperature Ts below the Curie point temperature Tc (Ts < TO; and polarization by the field captured by the traps of the negative charge having no time to relax for the time of cooling the film to Tc (Ts > Tc).