Recent Advances in Shallow Bulk Acoustic Wave Devices

Shallow bulk acoustic wave propagation in piezoelectric crystals is reviewed from the standpoint of work reported to date. It is compared to bulk and surface acoustic waves as to properties and device potential. Singly and doubly rotated cuts are considered, as are piezoelectric transduction energy trapping, equivalent networks, as well as areas of future work such as new materials other than quartz, and nonlinear effects.

Shallow Bulk Acoustic Wave Progress and Prospects

A surface-acoustic-wave (SAW) delay line integrated with a thin film amplifier can form the basis of a small high-stability microwave oscillator. Practical aspects of delay lines and the noise properties, stabilization frequency setting, and modulation of oscillators are presented.

Practical Aspects of Surface-Acoustic-Wave Oscillators

Thermal compensation of quartz SAW oscillators through electronic control of a phase shift element in the feedback loop has been demonstrated as a promising technique to obtain significant improvement over the usual ST-cut stability. tion of several design considerations limiting ultimate compensation accuracy is presented. SAW delay line these include deviations from the theoretically predicted parabolic temperature dependence as a result of mounting-induced crystal strains, surface moisture, and multiple acoustic signal interference. factors which limit the ability to produce a parabolic phase shift versus temperature that exactly mirrors the SAW dependence are discussed including thermal lag and undesired phase variations with temperature of the electronic components. An examinaFor the

http://ieeexplore.ieee.org/iel5/10279/32712/01534264.pdf

Design Considerations for Electronically Compensated SAW Delay Line Oscillators

The frequency-determining elements comprise two surface acoustic wave resonators (2, 3) (SAWs), in which two interdigital transducers (23, 24, 22, 34) are arranged between pairs of reflectors (21, 22, 31, 32). The resonators are differentiated by the apertures (26, 36) and the intermediate spaces (25, 35) between the interdigital converters. The apertures, interspaces and synchronous wavelengths in the SAWs are so selected, that the oscillator frequency has a given value at a given temperature.

Surface acoustic wave, two-gate oscillator with temperature stability, used in e.g. signal processing, frequency standard or sensor, includes interdigital resonators between reflectors

http://ieeexplore.ieee.org/iel5/10278/32711/01534024.pdf

T.I. Browning

Papers

A Novel Technique for Improving the Temperature Stability of SAW/SSBW Devices