Abstract: A filter device includes at least one first acoustic wave resonator and at least one second acoustic wave resonator. The at least one first acoustic wave resonator includes a first piezoelectric substrate and first and second IDT electrodes. The first piezoelectric substrate includes a piezoelectric layer with first and second main surfaces facing each other. The first IDT electrode is on the first main surface. The second IDT electrode is on the second main surface and faces the first IDT electrode. The at least one second acoustic wave resonator includes a second piezoelectric substrate and a third IDT electrode. The second piezoelectric substrate includes a piezoelectric layer with third and fourth main surfaces facing each other. The third IDT electrode is on one of the third and fourth main surfaces.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric film, a functional electrode, and a support. The support substrate includes a cavity. The piezoelectric film is provided on the support substrate to cover the cavity. The functional electrode is provided on the piezoelectric film to overlap the cavity when viewed in a plan view. The support is in the cavity of the support substrate to support the piezoelectric film. The functional electrode includes electrodes arranged in a direction crossing the thickness direction of the piezoelectric film. The electrodes include a first electrode and a second electrode. The first electrode and the second electrode oppose each other in a direction crossing the thickness direction of the piezoelectric film and are connected to different potentials. Adjacent ones of the electrodes overlap each other in a direction orthogonal to a longitudinal direction of the first electrode.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer, and an IDT electrode. The support substrate is made of quartz. The piezoelectric layer is provided on the support substrate and is made of LiTaO3. The IDT electrode is on the piezoelectric layer and includes electrode fingers. The IDT electrode is on a negative surface side of the piezoelectric layer. The cut angle of the piezoelectric layer is equal to or more than about 39° Y and equal to or less than about 48° Y.

Abstract: An acoustic wave device includes an Interdigital Transducer (IDT) electrode on a first main surface of a piezoelectric layer, a conductive material layer on a second main surface of the piezoelectric layer, and a dielectric layer provided between the piezoelectric layer and the conductive material layer. When a film thickness of the piezoelectric layer is represented as Tp[?] and a film thickness of the dielectric layer is represented as Td[?], the Formula (1) is satisfied or Td=0, where ? is a wavelength determined by an electrode finger pitch of the IDT electrode, and Tp[?]?about 0.025: Td[?]??2.369×(Tp[?])4 +2.721×(Tp[?])3 ?1.049×(Tp[?])2 +0.076×(Tp[?]) +0.095??Formula (1).

Abstract: In an acoustic wave device, a first IDT electrode is provided on a first main surface of a piezoelectric film, and a second IDT electrode is provided on a second main surface of the piezoelectric film. A crystal c-axis of the piezoelectric film is tilted with respect to a direction normal to the first and second main surfaces. A direction of an electric field generated between a busbar of a comb-shaped electrode and end portions of electrode fingers facing the busbar in the first IDT electrode and a direction of an electric field generated between a busbar and end portions of electrode fingers facing the busbar in the second IDT electrode are opposite directions.

Abstract: An acoustic wave device includes a piezoelectric body including first and second main surfaces facing each other, an IDT electrode provided on the first main surface of the piezoelectric body and including electrode fingers, a high acoustic velocity member on the second main surface side of the piezoelectric body, in which an acoustic velocity of a propagating bulk wave is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric body, and a first dielectric film provided on an upper surface of the electrode fingers, in which a portion where a dielectric is not present is provided between the electrode fingers of the IDT electrode.

Abstract: An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.

Abstract: An acoustic wave device includes a support substrate, an intermediate layer on the support substrate, a piezoelectric layer on the intermediate layer, a bonding layer between the support substrate and the piezoelectric layer, a low-resistivity layer between the support substrate and the piezoelectric layer, and an IDT electrode on the piezoelectric layer and including a pair of busbars and first and second electrode fingers. The low-resistivity layer closer to the piezoelectric layer than the bonding layer and includes Al as a main component.

Abstract: An acoustic wave device includes a support substrate, an intermediate layer on the support substrate, a piezoelectric layer on the intermediate layer and including first and second principal surfaces opposed to each other, a first IDT electrode on the first principal surface of the piezoelectric layer, and a second IDT electrode on the second principal surface of the piezoelectric layer to be opposed to the first IDT electrode. The support substrate is a quartz substrate with Euler angles (?, ?, ?) of about 0°±10°, 70°???170°, 90°±10°.

Abstract: An acoustic wave device includes a silicon oxide film, a lithium tantalate film, an IDT electrode, and a protection film that are laminated on a support substrate made of silicon. A wavelength normalized film thickness of a lithium tantalate film is denoted by TLT, an Euler angle is ?LT, a wavelength normalized film thickness of the silicon oxide film is TS, a wavelength normalized film thickness of the IDT electrode in terms of aluminum thickness is TE, a wavelength normalized film thickness of a protection film is TP, a propagation direction in the support substrate is ?Si, and a wavelength normalized film thickness of the support substrate is TSi. Values of TLT, ?LT, TS, TE, TP, and ?Si are set such that Ih corresponding to an intensity of a response of a spurious response represented by Formula (1) is greater than about ?2.4 in a spurious response.

Abstract: To provide an acoustic wave device capable of reducing or preventing fluctuations in electrical characteristics and reducing or preventing higher-order modes. An acoustic wave device of the present invention includes a support including a support substrate, a piezoelectric layer provided on the support and having a first principal surface and a second principal surface facing each other, a first IDT electrode provided on the first principal surface and including a plurality of electrode fingers, and a second IDT electrode provided on the second principal surface and including a plurality of electrode fingers. The second IDT electrode is embedded in the support. A dielectric film is provided on the first principal surface of the piezoelectric layer to cover the first IDT electrode. When a wavelength defined by an electrode finger pitch of the first IDT electrode is represented by ?, a thickness of the dielectric film is equal to or less than 0.15?.

Abstract: An elastic wave device includes a supporting substrate, a high-acoustic-velocity film stacked on the supporting substrate and in which an acoustic velocity of a bulk wave propagating therein is higher than an acoustic velocity of an elastic wave propagating in a piezoelectric film, a low-acoustic-velocity film stacked on the high-acoustic-velocity film and in which an acoustic velocity of a bulk wave propagating therein is lower than an acoustic velocity of a bulk wave propagating in the piezoelectric film, the piezoelectric film is stacked on the low-acoustic-velocity film, and an IDT electrode stacked on a surface of the piezoelectric film.

Abstract: An acoustic wave device includes N band pass filters with first ends connected to define a common connection and having different pass bands. At least one of the band pass filters includes acoustic wave resonators including a lithium tantalate film having Euler angles (?LT=0°±5°, ?LT, ?LT=0°±15°), a silicon support substrate, a silicon oxide film between the lithium tantalate film and the silicon support substrate, an IDT electrode, and a protective film. In at least one acoustic wave resonator, a frequency fh1_t(n) satisfies Formula (3) or Formula (4) for all m where m>n: fh1_t(n)>fu(m)??Formula (3); and fh1_t(n)<fl(m)??Formula (4). In Formulas (3) and (4), fu(m) and fl(m) represent the frequencies of the high-frequency end and the low-frequency end of the pass band in the m band pass filters.

Abstract: An elastic wave device includes a support substrate made of silicon, a piezoelectric film disposed directly or indirectly on the support substrate, and an interdigital transducer electrode disposed on one surface of the piezoelectric film. A higher-order mode acoustic velocity of propagation through the piezoelectric film is equal or substantially equal to an acoustic velocity Vsi=(V1)1/2 of propagation through silicon or higher than the acoustic velocity Vsi, where Vsi is specified by V1 among solutions V1, V2, and V3 with respect to x derived from Ax3+Bx2+Cx+D=0.

Abstract: An acoustic wave device includes a support including a support substrate, a piezoelectric layer provided on the support and including a first principal surface and a second principal surface facing each other, a first IDT electrode provided on the first principal surface, and a second IDT electrode provided on the second principal surface. The second IDT electrode is embedded in the support. At least one cavity is provided in a periphery of a portion of the support in which electrode fingers of the second IDT electrode is embedded.

Abstract: An acoustic wave device is provided between a first terminal that is an antenna terminal and a second terminal that is different from the first terminal, and includes a plurality of acoustic wave resonators. The plurality of acoustic wave resonators include a plurality of series arm resonators and a plurality of parallel arm resonators. When the acoustic wave resonator electrically closest to the first terminal among the plurality of acoustic wave resonators is an antenna end resonator, the antenna end resonator is a SAW resonator or a BAW resonator. At least one acoustic wave resonator other than the antenna end resonator among the plurality of acoustic wave resonators is a first acoustic wave resonator.

Abstract: Use of at least one microRNA comprising a nucleotide sequence set forth in any of SEQ ID NOS: 1 to 15 in a biological sample derived from a subject as a pancreatic cancer biomarker, wherein the pancreatic cancer biomarker is for determining whether the subject suffers from pancreatic cancer, for determining a pathological condition of the subject suffering or suffered from pancreatic cancer, or for identifying a test substance capable of treating pancreatic cancer.

Abstract: An acoustic wave device includes a (111)-oriented silicon substrate, a silicon nitride layer, a silicon oxide layer, a lithium tantalate layer, and an IDT electrode on the lithium tantalate layer. When the wavelength determined by the electrode finger pitch of the IDT electrode is ?, the thickness of the silicon nitride layer, SiN [?], the thickness of the silicon oxide layer, SiO2 [?], the thickness of the lithium tantalate layer, LT [?], and one of the Euler angles of the lithium tantalate layer, LT? [deg.], are thicknesses and an angle in ranges in which the phase of a first higher-order mode is about ?20° or less.

Abstract: An acoustic wave device includes a silicon oxide film, a piezoelectric body, and an interdigital transducer electrode laminated on a support substrate made of silicon. Where a wave length that is determined by an electrode finger pitch of the interdigital transducer electrode is ?, a thickness of the support substrate is greater than or equal to about 3?. An acoustic velocity of the first higher mode that propagates through the piezoelectric body is an acoustic velocity VSi=(V1)1/2 of bulk waves that propagate in the support substrate, which is determined by V1 out of solutions V1, V2, and V3 of x derived from the mathematical expression Ax3+Bx2+Cx+D=0, or higher than VSi.

Abstract: An acoustic wave device includes a silicon substrate, a first high-acoustic-velocity film on the silicon substrate, a first low-acoustic-velocity film on the first high-acoustic-velocity film, a second low-acoustic-velocity film on the first low-acoustic-velocity film, a second high-acoustic-velocity film on the second low-acoustic-velocity film, a piezoelectric film on the second high-acoustic-velocity film, and an IDT electrode on the piezoelectric film. Acoustic velocities of bulk waves propagating through the first and second high-acoustic-velocity films are higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric film. Acoustic velocities of bulk waves propagating through the first and second low-acoustic-velocity films are lower than an acoustic velocity of a bulk wave propagating through the piezoelectric film. Materials of the first and second low-acoustic-velocity films are different from each other.