A diaphragm for a piezoelectric micromachined ultrasonic transducer (PMUT) is presented having resonance frequency and bandwidth characteristics which are decoupled from one another into independent variables. Portions of at least the piezoelectric material layer and backside electrode layer are removed in a selected pattern to form structures, such as ribs, in the diaphragm which retains stiffness while reducing overall mass. The patterned structure can be formed by additive, or subtractive, fabrication processes.

A semi-wave transducer is provided that comprises a circular or elliptic transduction shell that has sidewalls captured between identical opposing upper and lower circular or elliptic conical segments (platens), each having a surface geometry of a radially symmetric wave shape that includes a center region and a rim wherein the distance between the center region of the upper and lower platens greater than the distance between the rims of the upper and lower platens. In some embodiments, the surface geometry of the platens may be a jinc function or a recurve function.

A sound source for acoustic communication, navigation, and networking of an underwater glider may include a cylindrical body, a rigid front section disposed anteriorly to the cylindrical body, a plurality of metal rods, a resonant pipe surrounding the rods, and a rod-mounted piezo-ceramic transducer disposed between the body and the front section. Each rod may be attached at a first end to an anterior portion of the body and at a second end to a posterior portion of the front section. The pipe may be disposed between the body and the front section. The transducer may be disposed within the pipe. A posterior end of the pipe may be separated from the anterior portion of the body by a first orifice, and an anterior end of the pipe may be separated from the posterior portion of the front section by a second orifice.

A transmitter for an acoustic logging tool includes an elongated housing, an acoustic energy generator, and a driver. The elongate housing defines a hollow interior and supports an acoustic energy generator, which includes four mutually orthogonally orientated bender bars that are electrically driveable to flex within the hollow interior in order to generate pressure-derived waves in a fluid surrounding the transmitter in use. The housing includes one or more transmissive windows via which flexing of the bender bars gives rise to propagation of one or more said waves in a said fluid. The driver electrically drives the bender bars to flex so as selectively to generate monopole, dipole, or quadrupole waves in a said fluid, with the poles of the dipole and quadrupole when generated selectively being aligned with normals to pairs of the bender bars or rotated 45° relative thereto.

Disclosed are devices and methods for marine geophysical surveying. An example device may comprise a shell, a base plate, wherein the base plate is coupled to the shell, a driver disposed within the shell, an inner spring element disposed within the shell, wherein the inner spring element is coupled to the driver, wherein outer ends of the inner spring element are coupled to outer ends of the inner spring element at spring element junctions, an outer spring element disposed within the shell, wherein outer ends of the outer spring element are coupled to the spring element junctions, and a back mass disposed on the outer spring element.

Flextensional transducers and methods of using flextensional transducers. The transducer includes a piezoelectric element and may include at least one endcap coupled with the piezoelectric element. The endcap may have an outer portion formed of a first material and an inner portion formed of a second material having a greater flexibility than the first material. The endcap may be coupled with an annular piezoelectric element near either its outer circumference or its inner circumference. The piezoelectric element may be a planar disk or have a curved bowl-shape. The transducer may be coupled with, and at least partially restrained by, a support structure. The transducer may also be configured to permit light to pass therethrough.

An adaptable seismic source system that includes a first seismic source having at least one moving plate and a second seismic source also having at least one moving plate. Each of the moving plates of the first and second seismic sources creating a pressure wave. Each seismic source is comprised of a fixed center plate having opposed sides and a pair of movable plates that are arranged at respective opposed sides of the center plate; a coupling member that is disposed between the first and second seismic sources for enabling a sliding action between the first and second seismic sources and a controller coupled with the first and second seismic sources for exciting the seismic sources to provide a combined output with a lower frequency spectrum.

Flextensional transducers and methods of using flextensional transducers. The transducer includes a piezoelectric element and may include at least one endcap coupled with the piezoelectric element. The endcap may have an outer portion formed of a first material and an inner portion formed of a second material having a greater flexibility than the first material. The endcap may be coupled with an annular piezoelectric element near either its outer circumference or its inner circumference. The piezoelectric element may be a planar disk or have a curved bowl-shape. The transducer may be coupled with, and at least partially restrained by, a support structure. The transducer may also be configured to permit light to pass therethrough.

A sound source for acoustic communication, navigation, and networking of an underwater glider may include a cylindrical body, a rigid front section disposed anteriorly to the cylindrical body, a plurality of metal rods, a resonant pipe surrounding the rods, and a rod-mounted piezo-ceramic transducer disposed between the body and the front section. Each rod may be attached at a first end to an anterior portion of the body and at a second end to a posterior portion of the front section. The pipe may be disposed between the body and the front section. The transducer may be disposed within the pipe. A posterior end of the pipe may be separated from the anterior portion of the body by a first orifice, and an anterior end of the pipe may be separated from the posterior portion of the front section by a second orifice.

A diaphragm for a piezoelectric micromachined ultrasonic transducer (PMUT) is presented having resonance frequency and bandwidth characteristics which are decoupled from one another into independent variables. Portions of at least the piezoelectric material layer and backside electrode layer are removed in a selected pattern to form structures, such as ribs, in the diaphragm which retains stiffness while reducing overall mass. The patterned structure can be formed by additive, or subtractive, fabrication processes.