A piezoelectric actuator includes: a plurality of discrete electrodes, which is disposed on one side of a piezoelectric element; a common electrode, which is disposed on the other side of the piezoelectric element; a plurality of discrete contacts, which are respectively connected to the plurality of discrete electrodes, and wherein the plurality of discrete electrodes include: a first discrete electrode; and a second discrete electrode, which is disposed at a position away from a corresponding discrete contact as compared with the first discrete electrode, wherein the common electrode includes: a first common electrode, which faces the first discrete electrode in the thickness direction; and a second common electrode, which is separated from the first common electrode in the surface direction and faces the second discrete electrode in the thickness direction, and wherein a connection wiring is provided to connect the first common electrode with the second common electrode.

An ultrasonic sensor includes a substrate. A first electrode and a first piezoelectric layer are stacked on one side of the substrate. A second electrode and a second piezoelectric layer are stacked on the other side of the substrate. A notch is defined in the first piezoelectric layer. And a conductive film is coated within the notch to couple the first electrode and the first piezoelectric layer.

The present disclosure relates to a Wafer-level-packaged Bulk Acoustic Wave (BAW) device, which includes a bottom electrode, a top electrode, a top electrode lead, a piezoelectric layer sandwiched between the bottom and the top electrodes, an enclosure, and an anti-reflective layer (ARL). Herein, an active region for a resonator is formed where the bottom electrode and the top electrode overlap. The top electrode lead is over the piezoelectric layer and extending from the top electrode. The enclosure includes a cap and an outer wall that extends from the cap toward the piezoelectric layer to form a cavity. The top electrode resides in the cavity and a first portion of the outer wall resides over the top electrode lead. The ARL, with a reflectance less than 40% R, is between the first portion of the outer wall and the top electrode lead.

The present disclosure relates to the bulk manufacture of transducer arrays, including arrays having at least one 3D printed (or otherwise additive manufactured) acoustic matching layers. In certain implementations, the manufactured transducers include a composite-piezoelectric transducer on a de-matching layer. In one implementation, by producing multiple arrays at once on a common carrier, and by using direct-deposit additive processes for the matching layers, the described processes greatly reduce the number of parts and the number of manual operations.

A piezoelectric bulk wave device that includes a piezoelectric thin plate that is made of LiTaO.sub.3, and first and second electrodes that are provided in contact with the piezoelectric thin plate. The piezoelectric bulk wave device utilizes the thickness shear mode of the piezoelectric thin plate made of LiTaO.sub.3, and of the Euler Angles (φ, θ, φ) of LiTaO.sub.3, φ is 0°, and θ is in the range of not less than 54° and not more than 107°.

A ferroelectric capacitor having a doped graphene bottom electrode and uses thereof are described. The doped graphene bottom electrode layer is deposited on a substrate with a ferroelectric layer deposited between the doped graphene layer and a top electrode.

There are provided an acoustic resonator module, and a method of manufacturing the same. An acoustic resonator module includes a resonating part disposed on a substrate and an inductor electrically connected to the resonating part, and having at least a portion disposed to be spaced apart from the substrate.

An acoustic resonator includes a resonating part including a piezoelectric layer located on a first electrode and a second electrode located on the piezoelectric layer; and a frame located on the second electrode along an edge of the resonating part, wherein the frame includes an inner surface and an outer surface, and the inner surface includes two inclined surfaces.

An acoustic wave filter includes a substrate, a first resonator disposed on the substrate, a second resonator disposed on the substrate to be spaced apart from the first resonator, a connector electrically connecting the first and second resonators, and a variable capacitor formed in the connector to tune a pass band frequency of the acoustic wave filter.

A method of making a temperature-compensated resonator is presented. The method comprises the steps of: (a) providing a substrate including a device layer; (b) replacing material from the device layer with material having an opposite temperature coefficient of elasticity (TCE) along a pre-determined region of high strain energy density for the resonator; (c) depositing a capping layer over the replacement material; and (d) etch-releasing the resonator from the substrate. The resonator may be a part of a micro electromechanical system (MEMS).