An 878 MHz Low Noise LiNbO₃/SiO₂/Sapphire Acoustic Delay Line Oscillator

A low phase noise surface acoustic wave (SAW) oscillator has been demonstrated using a wideband shear horizontal (SH)-SAW mode lithium niobate on sapphire (LNOS) acoustic delay line (ADL). With a low insertion loss (IL) of 4.3 dB, a large delay (Td) of 130 ns, and a high carrier frequency (fo) of 878 MHz provided by the LNOS SAW ADL, the oscillator prototype achieves low phase noise of -96.6 dBc/Hz at 1-kHz offset, -122.2 dBc/Hz at 10-kHz offset, and -158.9 dBc/Hz at noise floor, with a current consumption of only 16 mA from the sustaining amplifier. The proposed LNOS SAW oscillator competes favorably with state-of-the-art Lamb wave and SAW oscillators in the same frequency range, owing to the superior acoustic characteristics of the LNOS platform.