STUDY OF THE SENSITIVITY OF QUARTZ SURFACE-ACOUSTIC-WAVE OSCILLATORS TO STRESS EFFECT AND THERMAL-GRADIENTS

Sensitivity of Rayleigh wave devices to static thermal and mechanical stress has been theoretically and experimentally investigated in order to point out the existence of quartz cuts with a low-sensitivity to these phenomena. Two families of singly rotated surface acoustic wave cuts in the vicinity of the crystallographic angles (phi = 0 degrees; theta = -10 degrees; psi = 30 degrees) (TG cut) and (phi = 0 degrees; theta = 41.8 degrees; psi = 48.2 degrees) (close to STC cut) exhibit a low sensitivity to static temperature effects and to symmetrical radial in-plane compression, in a good agreement with theoretical models. Moreover, experimental investigations have shown that these cuts are less sensitive by an order of magnitude to dynamic thermal effects than the (ST, X) cut which is the present industry standard. Applications of these devices to ultra-stable oscillators could improve their performances when submitted to accelerations or to a severely perturbed thermal environment.