Low noise, UHF oscillators utilizing high overtone, lateral-field excitation, lithium tantalate resonators

The design and fabrication of high overtone, lateral-field excitation (LFE), LiTaO₃ resonators exhibiting unloaded Q values five times greater than those of similar frequency quartz surface acoustic wave (SAW) resonators were reported by R.W. Weinert et al. (1989). Recent improvements of that work with regard to suppression of resonator spurious modes are described, as is the design and performance of low-noise UHF oscillators incorporating the resonators as frequency control elements. Although excellent short-term frequency stability (near-carrier phase noise) performance has been demonstrated, resonator-controlled oscillator initial frequency drift rates are relatively high and appear to be reduced by electrode pattern design modifications made to obtain spurious modes suppression