| In order to improve the temperature stability of RF SAW devices, it is worth adding a layer of SiO2 on the surface of the piezoelectric substrate. This paper presents an original method, which allows the computation of the Harmonic Admittance of an infinite periodic grating covered with an SiO2 overlay. The origins of this method can be found in a previous paper [1]. By comparison with S. Ballandras [2] and K. Hashimoto [3] works, this methods allows to take into account the very efficient Chebyshev-like charge distribution, together with a classical FEM basis interpolation for the stresses. FEM is used to model mechanical behavior of complex shape electrodes and BEM using a periodic Green’s function Kernel is used to take into account the semi-infinite piezoelectric substrate. Validations are presented by comparison with K. Hashimoto’s software. |