TY - JOUR TI - Nonlinear acceleration sensitivity and frequency temperature behavior of quartz crystals DO - https://doi.org/doi:10.7282/T3KP84FS PY - 2016 AB - Quartz, composted of Silicon and Oxygen (Silicon Dioxide SiO2), has been the material of choice for stable resonators in wide applications of modern electronics. Due to decrease in the size of modern electronic devices, the nonlinearities of piezoelectric materials become more pronounced. Extensive study of the nonlinear behaviors of piezoelectric material is required. Three dimensional FEM modes are developed to calculate the effect of nonlinearities on the thickness shear mode resonant frequency. The intrinsic nonlinearities affecting the quartz resonators at high frequencies are acceleration sensitivity, force-frequency effect, and frequency-temperature behavior. A detailed study of the acceleration sensitivity of a rectangular AT-cut quartz plate is presented. For AT-cut quartz resonators with the crystal digonal X-axis perpendicular to plate X-axis, the in-plane acceleration sensitivity is found to be negligible compared to the out-of-plane (Y-axis) acceleration sensitivity. When the crystal digonal X-axis is parallel to plate X-axis, the Y-axis acceleration sensitivity is rectified. A DC bias field with an appropriate DC voltage could potentially yield a reduction of acceleration sensitivity in Y-axis direction of about two orders of magnitude. The behaviors of vibrating crystal plates under the action of external forces in fundamental mode and third overtone mode are studied. The plates were respectively subjected to diametrical compression forces and flexural bending in different configurations. Finite element models were developed using theory of small deformation superposed on finite initial deformation in Lagrangian formulation. The model results showed consistent trend with the experimental results by Fletcher and Mingins et al. The electrode stresses can be used to improve the frequency-temperature (f-T) behavior of ultra-high frequency (UHF) quartz resonators. The use of chromium-aluminum electrodes yields improved f-T behavior compared to the case where aluminum electrodes are used alone. The UHF quartz resonators must be treated as composite plates of quartz and electrode film since the ratio of electrode thickness to quartz plate thickness is significant. The quartz-aluminum composite plate rotates the f-T curve clockwise while the quartz-chromium composite plate rotates the f-T curve counter-clockwise. KW - Civil and Environmental Engineering KW - Quartz KW - Acceleration (Mechanics) LA - eng ER -