|
Surface acoustic wave devices are becoming increasingly popular in signal
processors in the VHF/UHF range, because of their size and simplicity.
However, it is extremely difficult for a beginner with a background in
signal processing to understand the operation of SAW devices because of a lack
of acquaintance with acoustics.
In fact, much of the literature involves a fairly high-level background in
acoustic fields and waves that is essential to understanding how energy is
coupled into and out of a surface acoustic wave delay line.
The first part of this book is ment to provie a brief introduction to transversal filters and acoustic waves for undergraduate students in electrical engineering who often have no formal acquaintance with either of these subjects.
Chapter 1, on transversal filters, is also useful as an introduction to SAW filters, which are basically transversal filters implemented with surface acoustic wave delay lines.
Chapter 2 describes the propagation and generation of uniform plane acoustic waves in piezoelectric solids emphasizing the analogy with electrical waves in a transmission line.
In Chapter 3 we discuss the surface acoustic wave, which is a nonuniform wave with complicated acoustic and piezoelectric fields coupled together.
Throughout the rest of the book we use the electrostatic potential at the surface (φ) as a measure of the amplitude of the SAW.
In the literature, an amplitude for the SAW is usually not defined precisely;
this leads to difficulties in problems where the phase information is important.
W have chosen the potential as the amplitude (rather than, say, strain) so as to eliminate repeated interconversion between electrical and (often unfamiliar) mechanical quantities.
The relationship of φ to the power carried by the SAW and to the other field quantities is described in Chapter 3 and a simple transmission line equivalent is developed.
The second part of this book describes the basic components that are used in SAW devices transducers, couplers, and reflectors.
Two chapters also includ ethe less common components: attenuators,
amplifiers, and waveguides.
Our treatment of transducers is slightly different from the usual description found in the literature.
In the literature, the radiation conductance (Ga) is determined directly by equating the power dissipated by it to the power carried away by the SAW.
We have found it useful to determine a transmitter response function (μ) and a receiver response function (gm) form which the radiation conductance is readily determined.
The advantage of these response functions is that unlike Ga, they preserve the phase information and can be used to analyze problems like a transducer in a cavity where the waves running in opposite directions interfere.
In Chapter 6, we have included a section that describes how the reflectivity and velocity shift per electrode can be determined form material parameters.
These rsults are fairly recent and have not yet been verified conclusively by experiments.
However, they agree with the available experimental data and we felt that the inclusion of these results will be useful.
The third part of this book describes the design and operation of two different types of SAW devices that have found widespread application: bandpass filters and resonators.
Matched filters, convolvers, and correlators have been omitted despite their considerable importance partly because of the diversity of the field and partly because of the author's lack of experience in this area.
The systems aspect of SAW devices has also not been discussed.
SOme of these topics are covered well in Surface Wave Filters
(ed. H. Matthews, Wiley, 1997) and Surface Acoustic Waves (ed. A. A. Oliner,
Springer-Verlag, 1978).
Only passing references have been made to topics of current research such as unidirectional transducers for low-loss filters or SAW in layered media (such as
ZnO on silicon).
At the start of each chapter we have summarized the contents and the important tables and results.
A large number of examples have been included to help clarify the ideas.
- ISBN Number:
- ISBN 0-13-877911-2 (hardcover-out of print, 1986)
- Available at:
- Amazon.com
- Barnes & Noble Used Books
- Publisher's Address:
- Prentice-Hall Publishing
|
|
Table of Contents |
 |
 |
 |
 |
Click on above images to view table of contents. |
|
