Features of the metallization influence on phase velocities of acoustic waves in piezoelectric plates

The paper presents an analysis of the influence of the load represented by two metal layers on the change in the phase velocity of the dispersion modes of the elastic Lamb and $SH$-waves in "Me/ZnO/Me" and "Me/AlN/Me" structures depending on the elastic wave frequency and the ratio of the metal layer to the piezoelectric layer thickness. Aluminum (Al), molybdenum (Mo) and platinum (Pt) are considered as the metal layer materials (Me). Only the elastic Lamb wave modes have localized maxima of the sensitivity curve $S$ for all types of structures. Systems with low values of acoustic impedances for layers and plates materials have maximum values of $S$ for metallization with thin layers, and also have minimal differences in the profiles of the components of the displacement vectors of the elastic wave. Systems with the most different values of acoustic impedances of layers and plates materials have maximum values of $S$ when metallized with thick layers, and also have maximum differences in the profiles of the components of the displacement vectors of the elastic wave.