Propagation characteristics of the fundamental symmetric Lamb wave in thin aluminum nitride membranes with infinite gratings

A theoretical approach for the analysis of Lamb waves in grating configurations based on the Floquet-Bloch theorem is developed. Subsequently, it is applied for the prediction of the propagation characteristics of the fundamental symmetric Lamb wave (S0) propagating in thin c-oriented aluminum nitride (AlN) membranes with different types of aluminum grating configurations. The calculations indicate the existence of a frequency stop band exhibiting a complex behavior. The proposed analysis is to be used for the design and optimization of high velocity thin-film Lamb wave resonators. It can easily be adapted for the analysis of arbitrary Lamb waves in periodic gratings.