A comparison of predicted and measured properties of doubly-rotated lithium tetraborate resonators

The authors previously presented calculations of the properties expected for doubly rotated lithium tetraborate resonators. The loci of cuts processing both first- and second-order temperature compensation for the simple thickness modes of plate resonators driven by thickness-directed electric fields were identified. Lithium tetraborate plates cut to the nominal orientations of these loci have since been obtained and measurements have been undertaken to verify the predictions. The mode spectra, equivalent circuit parameters, and frequency-temperature behavior have been examined for the first, third, and fifth harmonics for all three simple thickness modes of the resonators. The observed values of constants and piezocoupling are in good agreement with the predicted values. The measured temperature coefficients agree less well with the predicted values