Zero LSAW propagation loss in a SiO2/ periodic grating/LiTaO3 structure

A periodic electrode grating on rotated Y-cut lithium tantalate covered by a corrugated silicon dioxide film is investigated by the known impedance method/natural boundary element method. It is shown that the propagation loss of the leaky surface acoustic wave in such structure can be reduced considerably keeping a large reflection coefficient by changing the crystal cut angle. If the silicon dioxide thickness/wavelength ratio is equal to 20% and the electrode thickness/wavelength ratio is changed from 0% to 7%, then zero propagation loss at fundamental frequencies is achievable for cut angles in the range from 340 to 490 and from 430 to 710 for the cases of resonance and antiresonance, respectively.