Accession Number : ADP002481

Title :   Properties of AT Quartz Resonators on Wedgy Plates,

Corporate Author : MOTOROLA INC SCHAUMBURG IL

Personal Author(s) : Dworsky,L. N.

Report Date : 1983

Pagination or Media Count : 7

Abstract : It is well known in the quartz literature that non-parallel plate surfaces will cause deterioration in the performance of AT resonators. This deterioration consists of a decrease in the motional capacitance of the resonator's desired operating mode, often without a corresponding decrease in the motional capacitances of observed spurious modes. A model was developed for thickness-shear vibrations of a heavily electroded rectangular AT plate, assuming a small linear thickness variation (wedginess) across the plate. The model predicts that the standing waves corresponding to the different an harmonic overtone modes of vibration will bunch up in the thicker region of the plate. Higher order an harmonic modes will be less affected by the wedginess that will lower order an harmonics. The observed consequence of this behavior is that the motional capacitance of the lowest mode (the desired operating mode) will deteriorate, while the motional capacitances of the higher order modes (spurious modes) may not deteriorate at all. (Author)

Descriptors :   *Quartz resonators, *Plates, *Vibration, Plates, Thickness, Wave functions, Mathematical models

Distribution Statement : APPROVED FOR PUBLIC RELEASE