An elastic wave device includes a piezoelectric substrate made of LiNbO.sub.3, an IDT electrode on the piezoelectric substrate, and a dielectric film on the piezoelectric substrate and covering the IDT electrode. The IDT electrode includes a first electrode layer on or above the piezoelectric substrate and including W or an alloy including W, and a second electrode layer on or above the first electrode layer. A thickness of the first electrode layer is not smaller than 0.062λ, λ being a wavelength determined by a pitch of electrode fingers of the IDT electrode. The piezoelectric substrate has Euler angles of (0°± about 5°, θ, 0°± about 10°), ↓ being not smaller than 8° and not larger than 32°.

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.

An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, and an IDT electrode on a first main surface of the piezoelectric layer, wherein the support includes an air gap portion opened on a piezoelectric layer side, the support includes an inner side wall facing the air gap portion, and a high thermal conductive film is directly or indirectly laminated on at least a portion of a second main surface of the piezoelectric layer and extends to the inner side wall of the support.

An acoustic wave device includes a support substrate having a thickness in a first direction, a piezoelectric layer on the support substrate, and an interdigital transducer electrode on the piezoelectric layer and including first and second electrode fingers extending in a second direction crossing the first direction. The second electrode fingers face the first electrode fingers in a third direction orthogonal or substantially orthogonal to the second direction. The support substrate and the piezoelectric layer include a hollow therebetween at a position at least partially overlapping the interdigital transducer electrode in the first direction. At least one through hole penetrates the piezoelectric layer at a position not overlapping the interdigital transducer electrode in the first direction, and the through hole communicates with the hollow. A reinforcing support extends inside the hollow in a region overlapping the hollow and not overlapping the first and second electrode fingers.

An acoustic wave device includes a support substrate having a thickness in a first direction, a piezoelectric layer on the support substrate, an interdigital transducer electrode on the piezoelectric layer and including first and second electrode fingers, the first electrode fingers extending in a second direction crossing the first direction, the second electrode fingers extending in the second direction and facing the first electrode fingers in a third direction orthogonal or substantially orthogonal to the second direction, and a reinforcing film on the piezoelectric layer. The support substrate and the piezoelectric layer include a hollow therebetween at a position overlapping the interdigital transducer electrode in the first direction. At least one through hole penetrates the piezoelectric layer at a position not overlapping the interdigital transducer electrode in the first direction, and the through hole communicates with the hollow. The reinforcing film overlaps the hollow in the first direction.

An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, and an excitation electrode on the piezoelectric layer. A hollow portion is provided in the support and overlaps with at least a portion of the excitation electrode in plan view. The support includes a cavity opening on a side of the piezoelectric layer, and an inner wall surface connected to the cavity and facing the hollow portion. A functional film is provided on at least a portion of the inner wall surface and has an electromagnetic-wave absorption capacity in a wavelength range from about 0.2 .Math.m to about 1.2 .Math.m inclusive.

Guided Surface Acoustic Wave (SAW) devices with improved quartz orientations are disclosed. A guided SAW device includes a quartz carrier substrate, a piezoelectric layer on a surface of the quartz carrier substrate, and at least one interdigitated transducer on a surface of the piezoelectric layer opposite the quartz carrier substrate. The quartz carrier substrate includes an orientation that provides improved performance parameters for the SAW device, including electromechanical coupling factor, resonator quality factor, temperature coefficient of frequency, and delta temperature coefficient of frequency.

Aspects of this disclosure relate to a multiplexer that includes at least a first filter having a first passband and a second filter having a second passband. The first filter includes acoustic wave resonators coupled to a common node by a series inductor. The acoustic wave resonators start with a shunt acoustic resonator from the common node. The series inductor and the shunt acoustic resonator of the first filter are together arranged to increase a reflection coefficient of the first filter in the second passband.

A surface acoustic wave resonator arrangement comprises a piezoelectric substrate (100) and a surface acoustic wave resonator (110) which includes an interdigital transducer (111,112) disposed on the piezoelectric substrate (100). A trench (13 0) is disposed within the piezoelectric substrate (100) facing the resonator (110). Trench (130) causes reflected waves (143,144) in response to waves (141,142) leaking from the surface acoustic wave resonator. Trench (130) is configured such that the reflected acoustic waves (143,144) achieve phases at the edge (115) of the resonator (110) such that the accumulated phases of all the reflected waves received at edge (115) is zero or substantially zero, thereby avoiding constructive interference of the reflected waves with the acoustic waves resonating in the resonator. Thereby undesired acoustic coupling between resonators or influence of waves reflected at edges of the piezoelectric substrate or dicing lines is reduced.

Aspects of this disclosure relate to a packaged acoustic wave component with two acoustic wave devices interconnected by a thermally conductive frame, at least one of the acoustic wave devices including a multi-layer piezoelectric substrate. The multi-layer piezoelectric substrate includes a support layer and a piezoelectric layer disposed over the support layer. An interdigital transducer (IDT) electrode is disposed over the piezoelectric layer. The support layer has a high thermal conductivity, allowing heat generated by a first acoustic wave device with the multi-layer piezoelectric substrate to be transferred to a second acoustic wave device on which it is stacked to dissipate heat from the first acoustic wave device by way of the thermally conductive frame.