Book ChapterDOI
Basics of Acoustic Waves and Piezoelectricity
Colin Campbell
- pp 9-30
TLDR
In this paper, the basic properties of surface acoustic waves and their generation by an interdigital transducer (IDT) located on the free surface of a piezoelectric substrate are discussed.Abstract:
This chapter highlights the basic properties of surface acoustic waves and their generation by an interdigital transducer (IDT) located on the free surface of a piezoelectric substrate. The excitation of an IDT on a piezoelectric substrate can lead to the generation of bulk acoustic waves as well as surface waves. Bulk waves incident on the receiving IDT induce voltages. These interfere with the voltage signals due to received surface waves. The resultant voltage due to both sources can degrade the in-band performance specifications on amplitude, phase, or group delay response. Surface acoustic waves can be generated at the free surface of an elastic solid. In the SAW devices, the generation of such waves is achieved by the application of a voltage to a metal-film interdigital transducer (IDT) placed on the surface of a piezoelectric solid. Bulk acoustic waves can be characterized in terms of three modal types of mechanical excitation. One of these is a compressional wave, termed the longitudinal bulk wave, that is polarized in the direction of the acoustic wave propagation vector. The other two wave components, termed transverse or shear waves, have their vibrational modes. The chapter also outlines the acoustic bulk wave excitation by an IDT as a highly undesirable effect in SAW filter design that can cause severe degradation of filter performance and can also limit the fractional bandwidth obtainable with normal IDT structures.read more
Citations
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References
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Journal ArticleDOI
Surface-acoustic-wave devices for communications
R.M. Hays,C.S. Hartmann +1 more
TL;DR: In this article, the state of the art for surface-acoustic-wave (SAW) components from high-performance fixed-tuned devices to tunable or programmable filters is reviewed.
Journal ArticleDOI
Elastic surface waves
TL;DR: In this article, the authors exploit the properties of elastic surface waves to perform very complex signal processing functions, identical to those carried out by conventional electromagnetic devices, and demonstrate that the energy in the elastic surface wave can readily be sensed anywhere along its path.
Journal ArticleDOI
Spurious acoustic responses in SAW devices
TL;DR: In this article, theoretical plate mode calculations and corresponding experimental results for commonly used substrate orientations are presented, and quantitative terminal response predictions are possible when all the plate modes are included in the analysis.
Book ChapterDOI
On Rayleigh Waves and Related Propagating Acoustic Waves
TL;DR: A number of other studies have been undertaken over the years in an attempt to define the modes of propagation of specific mechanical structures, such as the work of Pochhamner and Chree on cylindrical bars, and of STONELEY [3] on the waves that can propagate at a plane boundary between two solids.