SAW oscillators with low vibration sensitivity

Abstract

Surface acoustic wave (SAW) oscillators with vibration sensitivities well below 1*10/sup -9/ fractional change in frequency per g have been demonstrated. Data are presented which indicate the need for a rigid support structure under an inherently low vibration sensitivity all quartz package (AQP) SAW device to achieve low vibration sensitivity at the oscillator level. An alumina stiffener supporting a hybrid circuit SAW oscillator provides this essential rigidity. Vibration sensitivity data for 26 oscillators in a 1.22-inch-square hybrid circuit package mounted on a 0.30-inch-thick alumina stiffener yielded an average value for the magnitude of the vibration sensitivity vector of 3.3*10/sup -10//g at a vibration frequency of 500 Hz. It also appears that some degree of vibration isolation at the AQP SAW device level may be achieved with the proper choice of material used to mount the AQP SAW device into the hybrid circuit package.