Abstract: Methods, apparatuses, and systems are disclosed for a transducer. The transducer can include a bottom plate formed from a first sheet of material, a top plate formed from a second sheet of material, and a middle portion. The middle portion includes a mid-upper element formed from a third sheet of material, with a mid-upper frame, a mid-upper mass, and a plurality of mid-upper attachment members coupling the mid-upper mass to the mid-upper frame. The middle portion can also include a central element formed from a fourth sheet of material, with the central element having a central frame and a central mass.

Abstract: Methods and apparatuses are disclosed that assist in sensing underwater signals in connection with geophysical surveys. One embodiment relates to a transducer including a cantilever coupled to a base. The cantilever may include a beam and a first coupling surface angularly oriented from the beam, and the base may include a second coupling surface angularly oriented from the beam and substantially parallel to the first coupling surface of the cantilever. The transducer may further include a sensing material coupled between the first coupling surface of the cantilever and the second coupling surface of the base.

Abstract: Methods, apparatuses, and systems are disclosed for forming a transducer. The transducer may include a bottom plate formed from a first sheet of material, a top plate formed from a second sheet of material, and a middle portion. The middle portion includes a mid-upper element formed from a third sheet of material, the mid-upper element having a mid-upper frame, a mid-upper mass, and a plurality of mid-upper attachment members coupling the mid-upper mass to the mid-upper frame. The middle portion also may include a central element formed from a fourth sheet of material, the central element having a central frame and a central mass.

Abstract: Methods and apparatuses are disclosed that assist in sensing underwater signals in connection with geophysical surveys. One embodiment relates to a transducer including a cantilever coupled to a base. The cantilever may include a beam and a first coupling surface angularly oriented from the beam, and the base may include a second coupling surface angularly oriented from the beam and substantially parallel to the first coupling surface of the cantilever. The transducer may further include a sensing material coupled between the first coupling surface of the cantilever and the second coupling surface of the base.

Abstract: A piezoelectric flexural sensing structure having increased sensitivity and decreased noise, without sacrifice of the sensor bandwidth. The structure is made up of a proof mass, a beam with a base and optionally having castellated bonding surfaces and two <011> poled bonding mode PMN-PT crystal plates mounted on the beam.

Abstract: The present invention is directed to an acoustic vector sensor, also called particle velocity sensor. <111> direction poled, shear mode, relaxor single crystals are used as the sensing elements. In addition, these crystal plates are cut at a special orientation such that they provide zero or minimum responses in the transverse directions, but have a maximum piezoelectric response in sensing direction. The piezoelectric sensor contains a proof mass, a base, and an aforementioned relaxor crystal. Three of the sensors are mounted orthogonally with a rigid case, and they are designated to sense the acoustic particle velocity in three designated directions, say X, Y, and Z. To solve the adverse lateral constraint problem (also known as clamping effect) associated with the relaxor crystal; reduced bonding area between the proof mass and the relaxor crystal are introduced.

Abstract: The present invention is directed to a sensing structure comprising four components: a central block proof mass, a continuous belt-shaped membrane (or one having another suitable shape), a piezoelectric sensing layer placed on top of the membrane, and a fixed mounting frame. Electrodes are attached to the top and the underside of the piezoelectric sensing layer. The structure results in an axisymmetric stress distribution.