Theoretical and Experimental Analysis of SAW Quartz Oscillator Acceleration Sensitivity

Abstract

The mechanisms leading to G-sensitivity in SAW oscillators are both theoretically and experi- mentally studied. This acceleration sensitivity results in a non-linear coupling, mainly due to the 3rd order non-linear elastic constants, between the high fre- quency surface wave and the static or quasistatic deformation induced by the acceleration field. This static deformation is calculated by means of a finite element method or for simpler cases by means of an in-plane stress distribution analyti- cal model. By using a perturbation method the relative frequency shifts are obtained. This method takes into account the non-linear coupling not only at the surface but all along the plate thickness. Measurements were performed as a function of the crystal mounting configuration with two or four supports.