Abstract: Aspects and embodiments disclosed herein include a surface acoustic wave device comprising a quartz substrate, a layer of a first lithium-based piezoelectric material disposed on an upper surface of the quartz substrate, a layer of a second lithium-based piezoelectric material formed of a material different from the first lithium-based piezoelectric material disposed on an upper surface of the layer of the first lithium-based piezoelectric material, and interdigital transducer electrodes disposed on an upper surface of the layer of the second lithium-based piezoelectric material.

Abstract: A method of forming an acoustic wave device is disclosed. The method can include providing a structure having a support substrate that includes a first substrate portion, a second substrate portion, and a third substrate portion between the first portion and the second portion, a piezoelectric layer that includes a first portion over the first substrate portion and a second portion over the second substrate portion, a first interdigital transducer electrode on the first portion of the piezoelectric layer, and a second interdigital transducer electrode on the second portion of the piezoelectric layer. the method can also include etching at least a portion of the piezoelectric layer such that a region over the third substrate portion is free from the piezoelectric layer.

Abstract: An acoustic wave filter includes a piezoelectric layer. A first acoustic wave device includes a portion of the piezoelectric layer and a first multi-layer interdigital transducer electrode disposed over the first portion of the piezoelectric layer. Additional acoustic wave devices are coupled to the first acoustic wave device, the additional acoustic wave devices including a second portion of the piezoelectric layer and a plurality of multi-layer interdigital transducer electrodes disposed over the second portion of the piezoelectric layer. At least one of the plurality of multi-layer interdigital transducer electrodes includes a layer that is thinner than a corresponding layer of the same material of the first multi-layer interdigital transducer electrode of the first acoustic wave device.

Abstract: A surface acoustic wave device can include a piezoelectric layer, first and second interdigital transducer electrodes in electrical communication with the piezoelectric layer, a reflector positioned between the first and second interdigital transducer electrodes such that the first and second interdigital transducer electrodes and the reflector are aligned along a longitudinal direction, and a temperature compensation layer over the first and second interdigital transducer electrodes and the reflector. The temperature compensation layer has a first region with a first thickness overlapping at least the first interdigital transducer electrode and a first portion of the reflector, a second region with a second thickness overlapping at least the second interdigital transducer electrode and a second portion of the reflector, and a sidewall between the first and second regions. The first thickness is greater than the second thickness.

Abstract: Aspects of this disclosure relate to an acoustic wave device having an overtone mode as a main mode. The acoustic wave device is sufficiently asymmetric on opposing sides of a piezoelectric layer over an acoustic reflector such that the main mode of the acoustic wave device is the overtone mode.

Abstract: A surface acoustic wave device has a piezoelectric substrate having a cut angle (e.g., the piezoelectric angle is cut so as to have a crystal orientation) that allows the surface acoustic wave device to operate as a longitudinally leaky surface acoustic wave device that confines the acoustic wave energy within the piezoelectric substrate and that has less propagation attenuation and a higher electromechanical coupling coefficient k2.

Abstract: Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a multi-layer mass loading strip. The mass loading strip has a density that is higher than a density of the temperature compensation layer. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can include a first layer for adhesion and a second layer for mass loading. The mass loading strip can suppress a transverse mode.

Abstract: Aspects of this disclosure relate to acoustic wave devices on stacked die. A first die can include first acoustic wave device configured to generate a boundary acoustic wave. A second die can include a second acoustic wave device configured to generate a second boundary acoustic wave, in which the second die is stacked with the first die. The first acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode on the piezoelectric layer, and high acoustic velocity layers on opposing sides of the piezoelectric layer. The high acoustic velocity layers can each have an acoustic velocity that is greater than a velocity of the boundary acoustic wave.

Abstract: A filter assembly operating at wider passband with an enhanced reflection coefficient is provided herein. In certain embodiments, the filter assembly comprises a first filter configured to allow signals received via an antenna node to pass at a first passband, the first filter including a plurality of resonators connected in series and parallel arms, the plurality of resonators of the first filter including a first type of resonator configured to broaden the first passband, at least a series resonator nearest to the antenna node or a shunt resonator nearest to the antenna node among the plurality of resonators of the first filter being a second type of resonator configured to improve reflection characteristics at a stopband of the first filter, and a second filter configured to allow the signals received via the antenna node to pass at a second passband using the second type of resonators.

Abstract: An acoustic wave element is disclosed. The acoustic wave element can include a piezoelectric layer that includes aluminum nitride. The acoustic wave element can also include a diamond like carbon layer. The acoustic wave element can further include an interdigital transducer electrode that is positioned on the piezoelectric layer. The piezoelectric layer is positioned between the interdigital transducer electrode and the diamond like carbon layer. The acoustic wave element is configured to generate a Lamb wave having a wavelength of ?.

Abstract: An acoustic wave device includes a piezoelectric layer and an interdigital transducer electrode disposed over the piezoelectric layer. The interdigital transducer electrode is thicker in a center region of the interdigital transducer electrode than in a gap region of the interdigital transducer electrode to thereby reduce a mass loading of the interdigital transducer electrode in the gap region. The interdigital transducer electrode has a layer of less dense material disposed of a layer of more dense material.

Abstract: A stacked acoustic wave device structure can include at least one surface acoustic wave device that supports a bulk acoustic wave resonator. The surface acoustic wave device includes a first piezoelectric layer with an interdigital transducer electrode on the first piezoelectric layer that generate a surface acoustic wave. In addition, a layer is located above the surface acoustic wave device along which the surface wave propagates. The bulk acoustic wave resonator is supported by the layer, the bulk acoustic wave resonator including an air cavity in contact with the layer, and the bulk acoustic wave resonator further includes a second piezoelectric layer above the air cavity and electrodes on opposing sides of the second piezoelectric layer.

Abstract: An acoustic wave device, a method of manufacture of the same, and a radio frequency filter including the same. The acoustic wave device comprises a multilayer piezoelectric substrate (MPS) including a layer of piezoelectric material having a lower surface disposed on an upper surface of a layer of a dielectric material having a lower surface disposed on an upper surface of a carrier substrate. An interdigital transducer (IDT) is disposed on the multilayer piezoelectric substrate and includes an active region configured to generate an acoustic wave. First and second high impedance portions are included within the multilayer piezoelectric substrate, the first and second high impedance portions each positioned outside the active region of the interdigital transducer and extending in the direction of propagation of the acoustic wave to be generated by the interdigital transducer. The first and second high impedance portions reduce side leakage and suppress transverse modes.

Abstract: Aspects of this disclosure relate to an acoustic wave device having an overtone mode as a main mode. The acoustic wave device is sufficiently asymmetric on opposing sides of a piezoelectric layer over an acoustic reflector such that the main mode of the acoustic wave device is the overtone mode.

Abstract: A delay line for radio frequency circuits comprises a piezoelectric substrate, a transmission single phase unidirectional transducer (SPUDT) disposed on the piezoelectric substrate, and a receive SPUDT disposed on the piezoelectric substrate and separated from the transmission SPUDT in a direction of transmission of a main acoustic wave mode utilized by the transmission SPUDT.

Abstract: An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate, a first dielectric film having a lower surface disposed on the IDT electrodes and the surface of the substrate, first strips formed of a first material having a density greater than a density of the first dielectric film disposed within the first dielectric film over tips of the interdigitated electrode fingers in the edge regions of the IDT electrodes, and second strips formed of a second material having a density greater than the density of the first dielectric film disposed within the first dielectric film in the gap regions of the IDT electrodes, laterally spaced from the first strips in a direction perpendicular to a direction of propagation of a main acoustic wave through the acoustic wave device, and extending only partially over the gap regions.

Abstract: An acoustic wave device is disclosed. The acoustic wave device can include a piezoelectric layer positioned over a substrate. The acoustic wave device can also include an interdigital transducer electrode positioned over the piezoelectric layer. The acoustic wave device can also include a grounding structure positioned over the piezoelectric layer. The acoustic wave device can also include a conductive layer positioned under the substrate such that the substrate is positioned between the conductive layer and the grounding structure. The acoustic wave device can further include an electrical pathway that electrically connects the conductive layer to the grounding structure.

Abstract: Aspects of this disclosure relate to bulk acoustic wave devices that have a raised frame structure, and filters that utilize the bulk acoustic wave devices. The raised frame structure can include a first raised frame layer that has a relatively low acoustic impedance. The raised frame structure can include a second raised frame layer that has a relatively high acoustic impedance. The first raised frame layer can extend inward further than the second raised frame layer. A width of the first raised frame layer that overlaps the first and second electrodes is between about 1.5 times to about 4 times larger than the combined thickness of the first electrode, the piezoelectric layer, and the second electrode.

Abstract: Aspects of this disclosure relate to bulk acoustic wave devices that have a raised frame structure, and filters that utilize the bulk acoustic wave devices. The raised frame structure can include a first raised frame layer that has a relatively low acoustic impedance. The raised frame structure can include a second raised frame layer that has a relatively high acoustic impedance. The first raised frame layer can extend inward further than the second raised frame layer. A width of the first raised frame layer that overlaps the first and second electrodes is between about 1.5 times to about 4 times larger than the combined thickness of the first electrode, the piezoelectric layer, and the second electrode.

Abstract: Aspects of this disclosure relate to an acoustic wave resonator with a patterned conductive layer. The acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode over the piezoelectric layer, and a temperature compensation layer over the interdigital transducer electrode. The interdigital transducer electrode can include a bus bar and fingers extending from the bus bar. The fingers can each include an edge portion and a body portion. The patterned conductive layer can overlap the edge portions of the fingers. The patterned conductive layer can conductive portions that are spaced apart from each other. A portion of the temperature compensation layer can be positioned between the patterned conductive layer and the interdigital transducer electrode.