Rapid Numerical Calculation of Rayleigh Surface Acoustic Wave Parameters for a Model of Coupling Modes

Introduction. Mathematical modeling is the most important stage in the development of devices based on surface acoustic waves (SAW). Computer simulations that have proven their efficiency in recent years can significantly reduce the time input and improve the accuracy of calculating the designed characteristics. A rapid analysis of the operating characteristics of the designed acoustoelectronic devices requires the knowledge of basic parameters of acoustic waves propagating along the device substrates.  Aim. Proposal and approbation of a methodology for calculating the key parameters necessary for modeling SAW devices based on the models of P-matrix and coupling modes, based on the example of analysis of Rayleigh waves by the finite element method.  Materials and methods. The theoretical part of the work was carried out using the mathematical theory of differential equations presented in a matrix form and the finite element method. Mathematical processing was conducted in the MatLab and COMSOL environments.  Results. An original technique for deriving SAW parameters for a model of coupling modes based on a rapid algorithm implemented in COMSOL was developed. A comparison of the calculated parameters of electromechanical coupling coefficient and velocity of acoustic waves over the substrate surface with those presented in literature showed their good agreement. Based on the derived parameters, a number of transversal filters were designed. A comparison of the calculated and experimentally measured values of the transmission coefficient was performed.  Conclusion. The proposed technique for analyzing infinite periodic electrodes by the finite element method based on an analysis of eigenfrequencies and static analysis made it possible to calculate the main parameters of Rayleigh waves in conventional substrates: lithium niobate, lithium tantalate and quartz. The practical significance lies in the use of the obtained parameters in the development of various classes of acoustoelectronic devices.