A Low Noise UHF Surface Transverse Wave Oscillator

A hybrid oscillator at 1.98 GHz has been developed using acoustic surface transverse wave (STW) delay lines operating at the third harmonic as the frequency controlling element. The STW delay lines were fabricated on 37.5° rotated Y-cut quartz substrates with a photolithographic technique. The Q value and the untuned insertion loss of the STW filters were 3400 and 21 dB, respectively. The phase noise and temperature stability of the oscillator were characterized. At a power output of 6.5 dBm a single sideband phase noise to carrier ratio of -100 dBc/Hz at 1 kHz and -70 dBc/Hz at 100 Hz was attained.