Sensitivity of SAW Delay Lines and Resonators to Vibration

Abstract

One of the major advantages of SAW controlled oscillators is their very low level FR4 noise sidebands. However, in many applications where this low noise level is important, the oscillator must operate in an environment with high vibration levels. Evaluating the degradation of noise sidebands due to vibration is very difficult at this time since very little information exists in the literature. Therefore, a number of measurements on rotated Y-cut quartz SAW devices were made to determine the level of noise sidebands in a vibration environment. A number of different substrate-mounting techniques have been evaluated for both delay lines and resonators. The devices were vibrated in each of three perpendicular directions with both random and sinusoidal vibration used. The observed sensitivity to vibration varied by two orders of magnitude for different mounting geometries, with the lowest sensitivities being comparable to that of a well-designed AT-cut bulk wave resonator.