Analysis of surface acoustic wave properties of the rotated Y-cut langasite substrate

The propagation characteristics of Rayleigh waves on a Y-rotated La₃Ga₅SiO₁₄ (langasite) substrate are evaluated with the use of newly obtained material constants. The calculated phase velocity, the power flow angle (PFA), the coupling electrome-chanical coefficient (K²), the temperature coefficient of delay (TCD) and the diffraction coefficient (y) are shown as contour maps. The revised numerical calculations were in much better agreement with the experimental results of the temperature characteristics on the langasite substrate with Euler angle (0°, 140°, ø). Moreover, the temperature characteristics as a function of the metal thickness were experimentally investigated. It was found that a thicker metal leads to a lower turnover temperature. Finally, an example of the frequency response of the transversal filter designed for IS95 is shown.