Dr. John L. Butler is Chief Scientist at Image Acoustics, Inc. and has had over forty years of both practical and theoretical experience in the design and analysis of underwater sound transducers and arrays. He has worked for and consulted to a number of underwater acoustics firms as well as Parke Mathematical Laboratories and the U. S. Navy. He has also taught courses in acoustics at Northeastern University, Naval Air Development Center, Raytheon Company, Harris Transducer Products and Hazeltine Corporation (now Ultra Ocean Systems, Inc.), Massa Products Corporation, Etrema Products, Plessey Australia, and Lund Institute of Technology, Sweden. He holds twenty seven patents and has presented or published well over thirty papers on electro-acoustic transducers. In 1977 he was elected fellow of the Acoustical Society of America and has received their 2015 Silver Medal Award for advancing the field of acoustic transducers and transducer arrays. His education includes Ph. D., Northeastern University, Boston, MA, and Sc. M., Brown University, Providence, RI.


Dr. Charles H. Sherman (1928-2009) received a B. S. degree in physics from the Massachusetts Institute of Technology in 1950. After his first job at TracerLab, Inc. in Boston, he became a research physicist at the Naval Underwater Sound Laboratory in New London, CT. He received M.S. and Ph.D. Degrees from the University of Connecticut and was elected Fellow of the Acoustical Society of America in 1974. He became a prominent expert in underwater transducers and arrays, presenting and publishing over thirty papers related to underwater acoustics. He also worked at Parke Mathematical Laboratories in Carlisle, MA, and taught advanced acoustics at the University of Connecticut and in the Ocean Engineering Department of the University of Rhode Island. He received the prestigious Decibel Award, which is presented to a scientist or engineer for outstanding contributions to sonar and underwateracoustics. After his retirement from the Sound Lab in 1988, he worked for Image Acoustics, Inc. and in 2007, co-authored the first edition of
Transducers and Arrays for Underwater Sound
, a technical monograph commissioned by the Office of Naval Research and the most comprehensive treatment to date of underwater transducers and arrays.

Offers a highly comprehensive text which is more extensive than the first edition

Casts new light on the basics of piezoelectric and magnetostrictive transducers

Includes sections on transducer and array advancements, as well as descriptions of legacy and new transducers and materials

Presents chapters in a systematic sequence for improved learning experience

Provides a glossary of key terms and an extensive appendix which includes sections on transducer materials, magnetostrictive and piezoelectric coefficients, frequently used formulas, hydrophone noise, relevant mathematics, transducer publications, and much more

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Chapter 1: Introduction. 1.1 Brief History of Underwater Sound Transducers. 1.2 Underwater Transducer Applications. 1.3 General Description of Linear Electroacoustic Transduction. 1.4 Transducer Characteristics. 1.5 Transducer Arrays.- Chapter 2: Electroacoustic Transduction. 2.1 Piezoelectric Transducers. 2.2 Electroconstrictive Transducers. 2.3 Magnetostrictive Transducers. 2.4 Electrostatic Transducers. 2.5 Variable Reluctance Transducers. 2.6 Moving Coil Transducers. 2.7 Comparison of Transducer Mechanisms. 2.8 Equivalent Circuits. 2.9 Thermal Considerations. 2.10 Extended Equivalent Circuits.- Chapter 3: Transducer Models. 3.1 Lumped Parameter Models and Equivalent Circuits. 3.2 Distributed Models. 3.3 Matrix Models. 3.4 Finite Element Models.- Chapter 4: Transducer Characteristics. 4.1 Resonance Frequency. 4.2 The Mechanical Quality Factor. 4.3 Characteristic Mechanical Impedance. 4.4 Electromechanical Coupling Coefficient. 4.5 Parameter Based Figure of Merit (FOM).- Chapter 5: Transducers as Projectors. 5.1 Principles of Operation. 5.2 Ring and Spherical Transducers. 5.3 Piston Transducers. 5.4 Transmission Line Transducers. 5.5 Flextensional Transducers. 5.6 Flexural Transducers. 5.7 Modal Transducers. 5.8 Low Profile Transducers.- Chapter 6: Transducers as Hydrophones. 6.1 Principles of Operation. 6.2 Cylindrical and Spherical Hydrophones. 6.3 Planar Hydrophones. 6.4 Bender Hydrophones. 6.5 Vector Hydrophones. 6.6 Plane Wave Diffraction Constant. 6.7 Hydrophone Thermal Noise.- Chapter 7: Projector Arrays. 7.1 Array Directivity Functions. 7.2 Mutual Radiation Impedance and the Array Equations. 7.3 Calculation of Mutual Radiation Impedance. 7.4 Arrays of Non-FVD Transducers. 7.5 Volume Arrays. 7.6 Near Field of Projector Array. 7.7 The Nonlinear Parametric Array.Doubly Steered Arrays.- Chapter 8: Hydrophone Arrays. 8.1 Hydrophone Array Directional Response. 8.2 Array Gain. 8.3 Sources and Properties of Noise in Arrays. 8.4 Reduction of Array Noise. 8.5 Arrays of Vector Sensors. 8.6 Steered Planar Circular Arrays. 8.7 Array Absorption and Transparency.- Chapter 9: Transducer Evaluation and Measurement. 9.1 Electrical Measurement of Transducers in Air. 9.2 Measurement of Transducers in Water. 9.3 Measurement of Transducer Efficiency. 9.4 Acoustic Responses of Transducers. 9.5 Reciprocity Calibration. 9.6 Tuned Responses. 9.7 Near-Field Measurements. 9.8 Calibrated reference Transducers.- Chapter 10: Acoustic Radiation from Transducers. 10.1 The Acoustic Radiation Problem. 10.2 Far Field Acoustic Radiation 10.3 Near-Field Acoustic Radiation. 10.4 Radiation Impedance. 10.5 Dipole Coupling to a Parasitic Monopole.- Chapter 11: Mathematical Models for Acoustic Radiation. 11.1 Mutual Radiation Impedance. 11.2 Green's Theorem and Acoustic Reciprocity. 11.3 Scattering and the Diffraction Constant. 11.4 Numerical Models for Acoustic Calculations.- Chapter 12: Nonlinear Mechanisms and Their Effects. 12.1 Nonlinear Mechanisms in Lumped Parameter Transducers. 12.2 Analysis of Nonlinear Effects. 12.3 Nonlinear Analysis of Distributed-Parameter Transducers. 12.4 Nonlinear Effects on the Electromechanical Coupling Coefficient.- Appendix.- Glossary of Terms.- Solutions for Odd-Numbered Exercises.-Index.