Frequency stability of high overtone bulk acoustic resonators

The authors report the results of phase noise measurements for high overtone bulk acoustic resonators (HBARs) operating at 640 MHz with insertion losses of 10-15 dB and unmatched Qs greater than 110 K. Noise measurements made on these resonators with input drive levels of 16 dBm have shown self-noise levels of S/sub y/(f=100 Hz)=8.0*10/sup -26/ for 1/f noise, which represents the state-of-the-art for a UHF resonator. It is concluded that HBAR technology provides the means for generating UHF and microwave signals exhibiting short-term frequency stability superior to that obtainable using quartz resonator based sources.<
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