Acoustic metamaterial

Patent metadata

Field	Value
Publication number	US-10573291-B2
Application number	US-201715837952-A
Country	US
Kind code	B2
Filing date	Dec 11, 2017
Priority date	Dec 9, 2016
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

A metamaterial comprising, a plurality of acoustic vector field sensors, each configured to sense an acoustic vector field of a fluid within a fluid-filled space in response to fluid waves, and producing an electrical signal corresponding to the sensed acoustic vector field; a processor configured to perform a time and space transform on the electrical signal; and at least one phased array transducer, configured to emit fluid waves according to a produced acoustic vector field pattern dependent on a result of the time and space transform, a within a portion of the fluid.

First claim

What is claimed is:

1. A metamaterial comprising:
a plurality of acoustic vector field sensors,
each of the plurality of acoustic vector field sensors comprising an electrically conductive fiber having a freely suspended portion with an elongated axis between two fixed electrodes within an applied magnetic field in a fluid having acoustic fluid waves within a fluid-filled space, wherein the electrically conductive fiber has a diameter less than 10 μm and senses an acoustic vector field in the fluid-filled space and a viscous drag of the acoustic fluid waves applied on the freely suspended portion causes movement of the freely suspended portion normal to the elongated axis corresponding to the acoustic vector field normal to the elongated axis,
wherein the applied magnetic field induces an electrical response in the electrically conductive fiber and the electrical response corresponds to the movement of the freely suspended portion,
to thereby sense the acoustic vector field, and produce an electrical signal representing the induced electrical response,
the plurality of acoustic vector field sensors configured to concurrently detect acoustic vector fields at different spatial locations;

a processor configured to perform a time and space transform on the electrical signals representing the sensed acoustic vector fields from the plurality of acoustic vector field sensors at the different spatial locations to produce a result; and
an output, configured to communicate a control signal for at least one phased array transducer, the control signal being defined to cause the at least one phased array transducer to emit the acoustic fluid waves within of the fluid and the acoustic fluid waves having an acoustic vector field pattern dependent on at least the result of the time and space transformed electrical signals.

2. The metamaterial according to claim 1 , further comprising the at least one phased array transducer, configured to receive the control signal, and emit the acoustic fluid waves having the acoustic vector field pattern dependent on at least the result of the time and space transformed electrical signals, within the portion of the fluid.

3. The metamaterial according to claim 2 , wherein the at least one phased array transducer has an emission pattern which does not directly emit waves toward the plurality of acoustic vector field sensors.

4. The metamaterial according to claim 2 , wherein the at least one phased array transducer has an emission pattern which emits waves that are sensed by at least one of the plurality of acoustic vector field sensors.

5. The metamaterial according to claim 1 , wherein the time and space transform causes a transfer function of an acoustic wave from the plurality of acoustic vector field sensors to the control signal to approximate a metamaterial transfer function.

6. The metamaterial according to claim 1 , wherein the time and space transform causes a transfer function of an acoustic wave from the plurality of acoustic vector field sensors to the control signal to approximate an acoustic cloaking device transfer function.

7. The metamaterial according to claim 1 , wherein the plurality of acoustic vector field sensors comprises a plurality of the electrically conductive fibers having a diameter less than 10 μm, each of the plurality of electrically conductive fibers being surrounded by the fluid, and being configured for movement within the fluid-filled space in response to the acoustic fluid waves, each of the plurality of the electrically conductive fibers having a radius and length such that a movement of the freely suspended portion of the respective electrically conductive fiber approximates a flow perturbation of the fluid surrounding the respective electrically conductive fiber by the acoustic fluid waves along an axis normal to the elongated axis of the respective electrically conductive fiber.

8. The metamaterial according to claim 1 , further comprising the at least one phased array transducer comprising a repeating regular spatial pattern of acoustic wave emitters, configured to receive the control signal, and emit the acoustic fluid waves having the acoustic vector field pattern dependent on the result of the time and space transformed electrical signals within the portion of the fluid.

9. The metamaterial according to claim 1 , further comprising the at least one phased array transducer comprising a plurality of acoustic wave emitters arranged in an irregular array, the irregular array having a non-uniform spacing pattern.

10. The metamaterial according to claim 1 , further comprising:
the at least one phased array transducer, the at least one phased array transducer being configured to receive the control signal and to emit the acoustic fluid waves; and
a self-contained power supply configured to supply sufficient power to the at least one phased array transducer to continually emit the acoustic fluid waves over a period of time comprising at least 10 seconds,
wherein the plurality of acoustic vector field sensors are configured to sense a vector flow of portions of the acoustic vector field of the fluid within the fluid-filled space concurrently with the emission of acoustic fluid waves in the fluid-filled space by the at least one phased array transducer.

11. The metamaterial according to claim 1 , wherein:
the plurality of acoustic vector field sensors surround a core in the fluid-filled space which interferes with propagation of the acoustic fluid waves in the fluid surrounding the core; and
the plurality of acoustic vector field sensors are arranged in a sensing array around the core to sense at least an axis of propagation of the acoustic fluid waves.

12. The metamaterial according to claim 11 ,
further comprising the at least one phased array transducer configured to emit the acoustic fluid waves within the portion of the fluid, disposed on at least an opposite side of the core from at least a portion of the plurality of acoustic vector field sensors;
wherein the processor is further configured to drive the at least one phased array to emulate a core which is transparent with respect to the acoustic fluid waves on the portion of the fluid.

13. The metamaterial according to claim 1 , wherein the time and space transform has a metamaterial transfer function between the plurality of acoustic vector field sensors and the output which represents a negative index.

14. A metamaterial method, comprising:
providing a plurality of acoustic vector field sensors, each of the acoustic vector field sensors configured to sense an acoustic vector field of a portion of a fluid within a fluid-filled space in response to acoustic fluid waves, and producing a plurality of electrical signals corresponding to the sensed acoustic vector field in the portion of the fluid, wherein
each of the acoustic vector field sensor comprises an electrically conductive fiber having a diameter less than 10 μm and having a freely suspended portion with an elongated axis between two fixed electrodes and the freely suspended portion is configured for movement in response to viscous drag of the fluid waves associated with the acoustic vector field, the freely suspended portion of the electrically conductive fiber being subject to a magnetic field that induces an electrical response in the electrically conductive fiber corresponding to the movement of the freely suspended portion, to thereby sense the acoustic vector field, and produce a respective electrical signal representing the sensed acoustic vector field at a spatial location;
receiving the electrical signals from each of the plurality of acoustic vector fie

Assignees

• Univ New York State Res Found

Inventors

• Hoffberg Steven M

Classifications

• G10K11/18

  Methods or devices for transmitting, conducting or directing sound (G10K11/02, G10K11/36 take precedence) · CPC title

• G10K15/04

  Sound-producing devices (G10K15/02 takes precedence) · CPC title

• G10K11/1785 Primary

  Methods, e.g. algorithms; Devices (G10K11/1781, G10K11/1783 take precedence) · CPC title

• H04K3/84

  related to preventing electromagnetic interference in petrol station, hospital, plane or cinema · CPC title

• H04K3/68

  using passive jamming, e.g. by shielding or reflection (shielding of apparatus or components against electric or magnetic field H05K9/00) · CPC title