1/f noise in etched groove surface acoustic wave (SAW) resonators

摘要

Measurements of 1/f (or flicker) frequency fluctuations in SAWnresonators fabricated with etched groove reflectors on single crystalnquartz have shown that the observed noise levels vary inversely withndevice size. These measurements were made on sixteen 450 MHz resonatorsnof four different sizes. The 1/f noise levels were also evaluated onntwenty-eight other SAW resonators ranging in frequency from 401 to 915nMHz. This additional data provides valuable information on thendependence of the flicker noise levels on resonator frequency. A modelnbased an localized, independent velocity fluctuations in the quartz isnproposed which correctly fits the observed size and frequency dependencenof the measured 1/f noise levels. This model suggests that the velocitynfluctuations originate in small regions (much less than ~5 Μm inndiameter) randomly distributed throughout the quartz with an averagenseparation of about 5 Μm between independent (incoherent) sources.nThe magnitude of the localized fractional velocity fluctuations,nΔv/v, averaged over a 5 micron cube is on the order of 1×10n-9