Measured properties of doubly-rotated lithium tetraborate resonators and transducers

Calculations of the properties expected for doubly rotated lithium tetraborate resonators and transducers have been presented by the authors previously (1989, 1991). A set of lithium tetraborate plates, cut to the nominal angles of cut of (YXwl) 40°/33° (TA-cut) and (YXwl) 19°/56° (TC-cut), has been supplied by a crystal grower. The plates have been processed into TETM resonators. The mode spectra and electrical circuit parameters of the resonators have been examined for the fundamental, third and fifth harmonics for all three TE modes of the resonators. The observed values of frequency constants and piezocoupling are in good agreement with the predicted values. The frequency-temperature behavior of the zero-temperature coefficient cuts has also been measured. The measured temperature coefficients are less well in agreement with the predicted values