An omnidirectional antenna to equip a sonar, the antenna centered around a longitudinal axis and comprises an assembly of emission rings stacked along the longitudinal axis, each emission ring formed around the longitudinal axis. The emission rings are assembled in groups of ring, the antenna comprises at least two groups of rings and each group of rings comprises at least two rings, the inter-ring spacings between the rings of one and the same group and the inter-group spacings between two successive groups of rings chosen so as to optimize the emission bandwidth and the sound level.

A submersible sound system may include a housing, an end piece, an elastic membrane, an end cap affixed to the elastic membrane, and a subwoofer speaker system disposed within the housing and supported by a speaker support. A bubble sound source may be defined by the speaker support, the speaker diaphragm, an anterior end of the housing, the elastic membrane, and the end cap. The housing, end piece, and a posterior surface of the speaker support may form a sealed enclosure. The sound system may include a tuning pipe disposed between the sealed enclosure and the bubble sound source. A Helmholtz resonator may be disposed anteriorly of the speaker system. Multiple sound system may be assembled to form a cluster. The cluster may be defined by the vertices of regular polyhedron. The sound systems may be controlled to maintain the speaker systems within acceptable thermal limits.

A survey system including a multibeam echo sounder and a beam selector for selecting beams with the largest amplitudes.

A method includes transmitting a focused ultrasound wave into a medium to form (i) an ultrasound intensity well within the medium that exhibits a first range of acoustic pressure and (ii) a surrounding region of the medium that surrounds the ultrasound intensity well and exhibits a second range of acoustic pressure that exceeds the first range of acoustic pressure. The method further includes confining an object within the ultrasound intensity well. Additionally, an acoustic lens is configured to be acoustically coupled to an acoustic transducer. The acoustic lens has a varying longitudinal thickness that increases proportionally with respect to increasing azimuth angle of the acoustic lens. Another acoustic lens is configured to be acoustically coupled to an acoustic transducer. The acoustic lens includes a plurality of segments. Each of the plurality of segments has a varying longitudinal thickness that increases proportionally with respect to increasing azimuth angle of the segment.

An example sonar transducer assembly is provided including at least one transducer element and a flexible printed circuit board (PCB) including at least one set of electrical connections for the at least one transducer element. The electrical connections include flex tabs configured to flex out of a PCB plane. The sonar transducer assembly also includes a support structure including an aperture for the at least one transducer element. The support structure is configured to support the body of the PCB, allow flexion of the flex tabs into the aperture, and retain the at least one transducer element in the at least one aperture. The transducer element is installed in a direction that is perpendicular to the PCB plane causing the flex tabs to flex outwardly from the PCB plane, thereby creating an elastic force of the flex tabs applied against opposing ends of the at least one transducer element.

A survey system including a multibeam echo sounder and a beam selector for selecting beams with the largest amplitudes.

A PCBA for use in a high-energy broadband electric field includes a low-voltage power supply and alternating conductive and dielectric layers. An outermost one of the conductive layers includes a dielectric surface switch having closely-spaced switch contacts. The first switch contact is connected to the positive terminal and the second switch contact connected to the negative terminal. Vias connect the conductive layers to the terminals through the respective first and second switch contacts to form power and ground planes. A metamaterial layer of nickel is doped with up to 20 percent phosphorus or chromium by weight, has a uniform thickness of less than 5 m, is sandwiched between interfacing surfaces of a pair of the conductive and dielectric layers, and evenly coats one of the interfacing surfaces. A sonobuoy system includes the PCBA, e.g., an Electronic Function Select board, a cylindrical housing, and an acoustic array.

Various implementations described herein are directed to a trolling device having a motor with a propeller coupled to the motor and a shaft configured to couple or mount the motor to a watercraft. The trolling device may include a housing encapsulating the motor and the housing may include a nosecone. A sonar transducer assembly may be incorporated within the housing or nosecone including a phased array configured to transmit sonar beams into an underwater environment.

An example sonar transducer assembly is provided including at least one transducer element and a flexible printed circuit board (PCB) including at least one set of electrical connections for the at least one transducer element. The electrical connections include flex tabs configured to flex out of a PCB plane. The sonar transducer assembly also includes a support structure including an aperture for the at least one transducer element. The support structure is configured to support the body of the PCB, allow flexion of the flex tabs into the aperture, and retain the at least one transducer element in the at least one aperture. The transducer element is installed in a direction that is perpendicular to the PCB plane causing the flex tabs to flex outwardly from the PCB plane, thereby creating an elastic force of the flex tabs applied against opposing ends of the at least one transducer element.

A method includes transmitting a focused ultrasound wave into a medium to form (i) an ultrasound intensity well within the medium that exhibits a first range of acoustic pressure and (ii) a surrounding region of the medium that surrounds the ultrasound intensity well and exhibits a second range of acoustic pressure that exceeds the first range of acoustic pressure. The method further includes confining an object within the ultrasound intensity well. Additionally, an acoustic lens is configured to be acoustically coupled to an acoustic transducer. The acoustic lens has a varying longitudinal thickness that increases proportionally with respect to increasing azimuth angle of the acoustic lens. Another acoustic lens is configured to be acoustically coupled to an acoustic that increases proportionally with respect to increasing azimuth angle of the segment.