A surface acoustic wave device includes a piezoelectric substrate, a supportive layer, a cover layer and a pillar bump. The supportive layer is disposed on the piezoelectric substrate and around a transducer, the cover layer covers the supportive layer, and the pillar bump is located in a lower via hole of the supportive layer and an upper via hole of the cover layer. The upper via hole has a lateral opening located on a lateral surface of the cover layer, and the pillar bump in the cover layer protrudes from the lateral surface of the cover layer via the lateral opening.

A filter device includes a substrate having piezoelectricity, a first filter including an IDT electrode disposed on the substrate, a terminal electrode disposed on the substrate, a first wiring electrode disposed on the substrate and connecting the first filter and a terminal electrode, and a dielectric film disposed above the substrate to cover the IDT electrode. At least a portion of the first wiring electrode is not covered with the dielectric film.

An elastic wave device includes a piezoelectric body including a main surface, an IDT electrode provided on the main surface of the piezoelectric body, and a wiring electrode provided on the main surface of the piezoelectric body and electrically connected to the IDT electrode, in which the wiring electrode includes a portion that extends to an edge of the main surface of the piezoelectric body, and a width of the wiring electrode on the edge is narrower than a width of the wiring electrode in a portion not on the edge.

An acoustic wave device includes a piezoelectric layer made of lithium niobate or lithium tantalate and including a first main surface, and an IDT electrode and a first dielectric film on the first main surface. A ratio d/p is equal to or less than about 0.5, when a thickness of the piezoelectric layer is d and a center-to-center distance between adjacent electrodes is p. The first dielectric film includes first and second surfaces facing each other. The second surface is a surface on a side of the piezoelectric layer. The IDT electrode includes third and fourth surfaces facing each other. The fourth surfaces are on the side of the piezoelectric layer. The first surface of the first dielectric film is at a same height as or higher than the third surfaces of the IDT electrode. A second dielectric film is on the first surface of the first dielectric film.

An acoustic wave device can include a substrate, a piezoelectric layer, a first electrode that includes a first bus bar and a first plurality of fingers extending from the first bus bar, and a second electrode that includes a second bus bar and a second plurality of fingers extending from the second bus bar. The second plurality of fingers can be interdigitated with the first plurality of fingers. The acoustic wave device can include a raised frame structure. The raised frame structure can be configured to suppress a transverse mode. The fingers can have widths that are greater than the distances between the fingers. The acoustic wave device can include a bus bar that includes a main section and a secondary section that are electrically connected by gap lines, which can have smaller width than the fingers. The acoustic wave device can include dummy fingers.

In an acoustic wave device, a piezoelectric body is directly or indirectly provided on a high acoustic velocity material layer, an interdigital transducer electrode is directly or indirectly provided on the piezoelectric body, the interdigital transducer electrode includes a first busbar, a second busbar spaced away from the first busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers, and a weighting is applied to the interdigital transducer electrode by providing a floating electrode finger not electrically connected to the first busbar or the second busbar or applied by providing an electrode finger formed by metallizing a gap between the first electrode fingers or a gap between the second electrode fingers to integrate the first electrode fingers or the second electrode fingers.

Acoustic wave resonators are disclosed that include a piezoelectric layer and an interdigital transducer electrode over the piezoelectric layer. The interdigital transducer electrode has a rotation angle and a tilt angle. The rotation angle and the tilt angle can together increase a figure of merit of the acoustic wave device. The rotation angle and the tilt angle can both be non-zero.

A front-end module may include an acoustic wave filter with a first and second interdigital transducer electrode, and a low noise amplifier (LNA) that converts a differential input to a single-ended output with respect to ground. The first interdigital transducer electrode may be single-ended with a first input bus bar configured to receive an input signal and a second input bus bar connected to ground. The second interdigital transducer electrode may be differential with a first output bus bar connected to a first output terminal and a second output bus bar connected to a second output terminal. The LNA may have a differential input connected to the acoustic wave filter, a first input transistor that receives a first signal from the first output terminal of the acoustic wave filter, and a second input transistor that receives a second signal from the second output terminal of the acoustic wave filter.

A surface acoustic wave device can have a piezoelectric layer and at least one interdigital transducer electrode thereon with a trapezoidal shape. This can be useful to fill dead space or voids between nonparallel elements on the layer. For example, an array with ranks of slanted interdigital transducer electrodes may not be aligned with non-slanted elements (e.g., a surface acoustic wave filter). This can leave voids or openings with unused portions of the piezoelectric layer. Trapezoidal elements such as those described here can solve this problem and help suppress transverse modes.

An acoustic wave device includes an IDT electrode with an inclined IDT structure on a piezoelectric substrate. An intersection region, where a first electrode finger and a second electrode finger overlap each other when viewed in an acoustic wave propagation direction, includes a central region and first and second low acoustic velocity regions on both sides of the central region. The first and second low acoustic velocity regions have an asymmetric shape about a central axis extending in a length direction of the first and second electrode fingers.