An acoustic wave device is disclosed. The acoustic wave device includes a piezoelectric layer, an interdigital transducer electrode positioned over the piezoelectric layer, and an anti-refection layer over a conductive layer of the interdigital transducer electrode. The conductive layer can include aluminum, for example. The anti-reflection layer can include silicon. The anti-reflection layer can be free from a material of the interdigital transducer electrode. The acoustic wave device can further include a temperature compensation layer positioned over the anti-reflection layer in certain embodiments.

Certain aspects of the present disclosure provide a surface acoustic wave (SAW) resonator with piston mode design and electrostatic discharge (ESD) protections. An example electroacoustic device generally includes a piezoelectric material and a first electrode structure disposed above the piezoelectric material. The first electrode structure comprises first electrode fingers arranged within an active region having a first region and a second region. At least one of the first electrode fingers has at least one of a different width or a different height in the first region than in the second region, and the first electrode fingers comprise a first electrode finger that has a width or height in the second region that is less than a corresponding width or height of the at least one of the first electrode fingers in the second region.

An acoustic wave device is disclosed. the acoustic wave device can include a support substrate, a first solid acoustic mirror over the support substrate, a piezoelectric layer positioned over the first solid acoustic mirror, an interdigital transducer electrode at least partially embedded in the piezoelectric layer, and a second solid acoustic mirror over the over the piezoelectric layer. The interdigital transducer electrode is configured to generate an acoustic wave having a wavelength of L. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the acoustic wave.

A longitudinally leaky surface acoustic wave device is disclosed. The longitudinally leaky surface acoustic wave device can include a support substrate, a first solid acoustic mirror over the support substrate, a piezoelectric layer positioned over the first solid acoustic mirror, an interdigital transducer electrode over the piezoelectric layer, and a second solid acoustic mirror over the over the interdigital transducer electrode. The interdigital transducer electrode is configured to generate an acoustic wave that propagates in a lateral direction. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the acoustic wave. The piezoelectric layer can have a cut angle of (90±30, 90±30, 40±30).

An acoustic wave device includes a support substrate including a main surface including first and second regions adjacent to each other in a plan view; a multilayer body including an intermediate layer in the first region of the support substrate and a piezoelectric layer on the intermediate layer, and including a side surface; an IDT electrode on the piezoelectric layer of the multilayer body; and an insulating film in the second region of the support substrate to cover the side surface of the multilayer body. An angle defined between the main surface of the support substrate and the side surface of the multilayer body is a tilt angle, and the side surface of the multilayer body includes portions having different tilt angles at a portion covered with the insulating film.

A sensor device that includes an integrated sensor assembly having a surface acoustic wave (SAW) sensor disposed on a piezoelectric substrate. The SAW sensor is adapted to measure an environmental condition of an environment in response to an RF signal. The SAW sensor includes an interdigitated transducer (IDT) formed on a substrate having at least a layer of a piezoelectric material. The SAW sensor includes either one or more SAW reflectors of a second IDT formed on the piezoelectric material. The SAW sensor further includes an RF antenna formed on the piezoelectric material. The SAW sensor and the RF antenna are integrated with one another on the piezoelectric material.

An elastic wave device in which an IDT electrode defines an excitation electrode on a piezoelectric layer, an acoustic reflection layer is laminated on a first main surface of the piezoelectric layer, the acoustic reflection layer includes high acoustic impedance layers with a relatively high acoustic impedance and low acoustic impedance layers with a relatively low acoustic impedance, and the acoustic reflection layer has an unwanted wave reflection suppression structure in which reflection of unwanted waves toward the piezoelectric layer side is significantly reduced or prevented.

A transmission filter includes a transmission filter circuit and an additional circuit. The transmission filter circuit is provided between a first terminal and a second terminal. Between the first terminal and the second terminal, the additional circuit is connected in parallel with at least a portion of the transmission filter circuit. The additional circuit includes an IDT electrode group including a plurality of IDT electrodes located next to each other in an acoustic wave propagation direction and two reflectors that sandwich the IDT electrode group and having different numbers of pairs of electrode fingers.

An acoustic wave device includes first and second acoustic wave elements. The first acoustic wave element is disposed on a piezoelectric substrate, and includes at least one first IDT electrode. The second acoustic wave element is disposed on the piezoelectric substrate, and includes at least one second IDT electrode. The first and second acoustic wave elements are adjacent to each other in the direction of acoustic wave propagation. A diffracting component that diffracts an acoustic wave is disposed between the first IDT electrode and the second IDT electrode. The diffracting component includes a gap that defines and functions as a slit to diffract an acoustic wave.

An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and two reflectors on both sides of the interdigital transducer electrode in an acoustic wave propagation direction. The reflectors include first and second busbars and first to third electrode fingers, respectively, and the first and second busbars are opposed to one another. The first busbars and the second busbars are connected by at least one third electrode finger. The reflectors each include a center area located centrally in a length direction and a first high-acoustic-velocity area that is located between the center area and the first busbars and has an acoustic velocity higher than the acoustic velocity of the center area, where the length direction is a direction in which the first to third electrode fingers extend.