SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  N07-075 (Navy)
Title:  High Frequency Broadband Hybrid Transducer/Amplifier
Research & Technical Areas:  Sensors, Electronics, Battlespace

Acquisition Program:  PEO-IWS
  Objective:  Develop a very compact underwater projector/power amplifier module that can be assembled in various array configurations.
  Description:  Develop a broadband underwater transducer that is very compact and has an integral power amplifier configured such that the total package can be treated as a module for inclusion in an array that can be affixed to or embedded in the hull or structure of a small unmanned undersea vehicle or glider or in the coating of a surface combatant or submarine. The desire to develop a self-contained transducer/amplifier in a volume that is considerably smaller than present systems dictate transduction material and mechanism needs that must be novel. Nesting and hybrid combinations of materials and mechanisms are encouraged. The overall efficiency of the module is an important factor and it can be envisioned that an advanced energy source (stored or collected from the environment) that could be added to the module would be an excellent total self-contained system.

  PHASE I: Identify the concept and develop detailed models to simulate the performance of the complete device.
  PHASE II: Develop and test a prototype transducer and amplifier. Based on the proposed approach and current Naval needs the Phase II effort may include the need for access to classified data.

  PHASE III: Fabricate several prototype modules to demonstrate array behavior and performance. PRIVATE SECTOR COMMERCIAL POTENTIAL/

  DUAL-USE APPLICATIONS: There is a continuing need in the commercial sector for small transducer arrays operating over several octaves of frequency and capable of reasonable output powers. There would be a market in both military systems and in commercial fishing and oceanographic systems.

  References:  1. K.R. Erikson, G. Zipfel, S.C. Butler, G.S. Edelson and E.W. Will, “Innovative Power Amplifier and Technologies for High Frequency, Broadband Sonar Arrays,” Acoustical Imaging, Volume 28, edited by M.P. Andre, Kluwer Academic Publishers, Boston, MA, 2006. 2. S.C. Butler, “Integrated Co-Fired Triply Resonant Broadband Projector and Copolymer Hydrophone Transducer”, Proceedings of the Institute of Acoustics, Sonar Transducers and Numerical Modelling in Underwater Acoustics at National Physical Lab. Teddington, UK, 21-22 March 2005. 3. R. F. W. Coates, “The Design of Transducers and Arrays for Underwater Data Transmission,” IEEE Journal of Oceanic Engineering, Vol. 16, No. 1, January 1991. 4. S. C. Thompson, M. P. Johnson, E. A. McLaughlin and J. F. Lindberg, “Performance and Recent Developments with Doubly Resonant Wideband Transducers,” Proceedings of the Third International Workshop Transducers for Sonics and Ultrasonics, Orlando, Florida, U.S., May 1992.

Keywords:  transducer, array, power amplifier, digital, energy harvesting, conformal, underwater

Additional Information, Corrections, References, etc:
Ref #1: xAI Paper Rev. D 10-10-05.doc
Ref #1: xAI Paper Rev. D 10-10-05.doc

Questions and Answers:
Q: 1. Are there any geometric constraints for the module? That is, the overall shape and aspect ratio of the module?
2. Is the module to be used as a tranceiver, XMTR and RCVR?
A: 1. Geometric restraints are needed to permit the modules to be assembled as an array. If the transducer radiates through a traditional head mass it is desired that the dimensions of the head be half an acoustic wavelength or less so that an array of these modules can be electrically steered. It is desired that the dimensions of the total module not exceed the size of the head mass to facilitate assembling them in a closely packed array. To permit installation on a variety of vehicles it would be desired that the depth of the modules be on the order of 4-5 inches or less.

2. The modules should be capable of both transmission and reception.
Q: I have a few questions regarding the transducer/amplifier in this project:

1)What is the frequency range of the transducer you are interested in?
2)What is the bandwidth needed?
3)What is Output pressure/Output power requirement?
4)What is the detection sensitivty requirement?
5)Operation depth under water?
6)What is the operating voltage range? Is a smaller voltage is desired?
7)What is the element size if an array is used? Total size of device or directionality?
A: 1. With regards to the frequency band and power desired I am pasting in the answer to another question that was queried on that subject.

2. Regarding the frequency range and power levels, the goals are deliberately vague in order to permit innovation. Notionally HF is thought of as 10-40 kHz but lower frequencies are desired if the impact on size and weight is not oppressive. Thus a design that operated over the frequency band from 7-30 kHz would be desired assuming that the size does not grow in a linear scaling factor but rather stays small due to an innovative design. The acoustic output power should be a minimum of 20-30 watts but more is, of course, desirable.

3. Broad bandwidth is highly desired. When the frequency band is stated as 10-40 kHz or 7-30 kHz that means that the response should be flat within
3 dB over the band with a 3 dB drop at band edges.

4. The receive sensitivity of the transducer should be typical of a resonator of that design. A good target number is -185 dB re a microbar

5. The transducer should be able to withstand pressures up to 600 feet in depth.

6. The lower the voltage the better since that tends to minimize reliability issues and simplifies power amplifier and tuning demands.

7. The radiating size of the transducer should be on the order of a half wavelength in the middle of the band so that if an array is assembled of these modules it may be electrically steered with good behavior. The design should be tailored such that the elements/modules can be bunched together to make an array.
Q: What frequency range and power level are we talking about?
A: Regarding the frequency range and power levels, the goals are deliberately vague in order to permit innovation. Notionally HF is thought of as 10-40 kHz but lower frequencies are desired if the impact on size and weight is not oppressive. Thus a design that operated over the frequency band from 7-30 kHz would be desired assuming that the size does not grow in a linear scaling factor but rather stays small due to an innovative design. The acoustic output power should be a minimum of 20-30 watts but more is, of course, desirable.
Q: 1. Are there any geometric constraints for the module? That is, the overall shape and aspect ratio of the module?
2. Is the module to be used as a tranceiver, XMTR and RCVR?
A: 1. Geometric restraints are needed to permit the modules to be assembled as an array. If the transducer radiates through a traditional head mass it is desired that the dimensions of the head be half an acoustic wavelength or less so that an array of these modules can be electrically steered. It is desired that the dimensions of the total module not exceed the size of the head mass to facilitate assembling them in a closely packed array. To permit installation on a variety of vehicles it would be desired that the depth of the modules be on the order of 4-5 inches or less.

2. The modules should be capable of both transmission and reception.
Q: I have a few questions regarding the transducer/amplifier in this project:

1)What is the frequency range of the transducer you are interested in?
2)What is the bandwidth needed?
3)What is Output pressure/Output power requirement?
4)What is the detection sensitivty requirement?
5)Operation depth under water?
6)What is the operating voltage range? Is a smaller voltage is desired?
7)What is the element size if an array is used? Total size of device or directionality?
A: 1. With regards to the frequency band and power desired I am pasting in the answer to another question that was queried on that subject.

2. Regarding the frequency range and power levels, the goals are deliberately vague in order to permit innovation. Notionally HF is thought of as 10-40 kHz but lower frequencies are desired if the impact on size and weight is not oppressive. Thus a design that operated over the frequency band from 7-30 kHz would be desired assuming that the size does not grow in a linear scaling factor but rather stays small due to an innovative design. The acoustic output power should be a minimum of 20-30 watts but more is, of course, desirable.

3. Broad bandwidth is highly desired. When the frequency band is stated as 10-40 kHz or 7-30 kHz that means that the response should be flat within
3 dB over the band with a 3 dB drop at band edges.

4. The receive sensitivity of the transducer should be typical of a resonator of that design. A good target number is -185 dB re a microbar

5. The transducer should be able to withstand pressures up to 600 feet in depth.

6. The lower the voltage the better since that tends to minimize reliability issues and simplifies power amplifier and tuning demands.

7. The radiating size of the transducer should be on the order of a half wavelength in the middle of the band so that if an array is assembled of these modules it may be electrically steered with good behavior. The design should be tailored such that the elements/modules can be bunched together to make an array.
Q: What frequency range and power level are we talking about?
A: Regarding the frequency range and power levels, the goals are deliberately vague in order to permit innovation. Notionally HF is thought of as 10-40 kHz but lower frequencies are desired if the impact on size and weight is not oppressive. Thus a design that operated over the frequency band from 7-30 kHz would be desired assuming that the size does not grow in a linear scaling factor but rather stays small due to an innovative design. The acoustic output power should be a minimum of 20-30 watts but more is, of course, desirable.

Record: of