On the Efficiency of Excitation of High Coupling Plate Acoustic Modes

Blotekjear's formalism is applied towards the analysis of the IDT excitation efficiency of high coupling plate acoustic wave modes in thin-film piezoelectric membranes. The results indicate an offset of the optimum mark-to-pitch ratio towards values below 0.5 for the excitation of the fundamental mode and the suppression of the 3
_rd
harmonic. The predicted behavior is confirmed by FEM analysis of the excitation of the low-dispersion SH0 mode in thin-film 30Y-X LiNbO3 membrane.