Abstract: A filter device includes a first filter and a second filter. The first filter and the second filter are disposed in parallel between a first terminal and a second terminal. A first passband of the filter device includes at least part of a second passband of the first filter. The first passband includes at least part of a third passband of the second filter. The second passband is narrower than the first passband. The third passband is narrower than the first passband. The third passband has a center frequency higher than a center frequency of the second passband. The first filter includes multiple elastic wave resonators and a first capacitive element. The first capacitive element is connected in parallel with the first elastic wave resonator.

Abstract: A communication system according to an embodiment of the present disclosure is a communication system that transmits a signal from a plurality of transmission devices to one reception device via a transmission path. In the communication system, the transmission path includes a branch point at a midpoint, includes a plurality of first signal lines that couples the transmission devices and the branch point to each other, and further includes a second signal line that couples the branch point and the reception device to each other. Of the plurality of first signal lines or the second signal line, at least the plurality of first signal lines has a resistor element in proximity to the branch point.

Abstract: Modern RF front end filters feature acoustic resonators in a film bulk acoustic resonator (FBAR) structure. An acoustic filter is a circuit that includes at least (and typically significantly more) two resonators. The acoustic resonator structure comprises a substrate including sidewalls and a vertical cavity between the sidewalls and two or more resonators deposited in the vertical cavity.

Abstract: Aspects of this disclosure relate to a multiplexer that includes a first filter and a second filter coupled to a common node. The first filter includes an acoustic filter arranged to filter a radio frequency signal, a matching network coupled between the acoustic filter and the common node, and a parallel circuit coupled in series between the acoustic filter and the common node. The parallel circuit includes an inductive component in parallel with a capacitive component. In certain instances, the first filter is coupled to the common node via a switch, the matching network is coupled to a node between the acoustic filter and the switch, and the parallel circuit is coupled in series between the acoustic filter and the switch. Related methods, radio frequency modules, and wireless communication devices are also disclosed.

Abstract: An elastic wave device includes an IDT electrode on a second main surface of an element substrate that includes a piezoelectric layer, a support layer on the second main surface and surrounding the IDT electrode, a cover member on the support layer, and routing wiring lines extending from the second main surface of the element substrate onto side surfaces of the element substrate.

Abstract: A solidly mounted resonator having an electromagnetic shielding structure and a method for manufacturing the same. The solidly mounted resonator includes: a substrate; an acoustic-wave reflecting layer formed on the substrate; a resonance function layer formed on the acoustic-wave reflecting layer; and a metal shielding wall formed on the substrate, wherein the metal shielding wall surrounds an effective region in the acoustic-wave reflecting layer and the resonance function layer. The electromagnetic shielding structure is formed simultaneously with the resonator, and it is not necessary to provide an additional electromagnetic shielding device. An influence of an external or internal electromagnetic interference source on the resonator is avoided while ensuring a small dimension and a high performance of the resonator.

Abstract: An acoustic waveguide having high-Q resonator characteristics is disclosed and a fabrication method is described. Various waveguide-based test-vehicles, implemented in single crystal silicon and transduced by thin aluminum nitride films, are demonstrated. Silicon resonators with type-I and type-II dispersion characteristics are presented to experimentally justify the analytical mode synthesis technique for realization of high quality-factor silicon Lamb wave resonators. An analytical design procedure is also presented for geometrical engineering of the waveguides to realize high-Q resonators without the need for geometrical suspension through narrow tethers or rigid anchors. The effectiveness of the dispersion engineering methodology is verified through development of experimental test-vehicles in 20 ?m-thick single-crystal silicon (SCS) waveguides with 500 nm aluminum nitride transducers.

Abstract: An acoustic wave device includes a piezoelectric body portion, an interdigital transducer electrode connected to a first terminal and a second terminal, and a reflector connected to the second terminal. In the interdigital transducer electrode, in the interdigital transducer electrode, where, of a group of electrode fingers, the electrode finger located at one end in a second direction is a first end electrode finger and the electrode finger located at another end is a second end electrode finger, the first end electrode finger is located between the reflector and the second end electrode finger in the second direction. An outer busbar portion of one of a first busbar and a second busbar, not connected to the first end electrode finger, is located on an inner side in the second direction relative to a center portion, in a first direction, of the first end electrode finger.

Abstract: A filter device includes a first path, a second path, and a capacitor. The first path includes at least one ladder filter circuit and connects a first terminal and a second terminal. The at least one ladder filter circuit includes a parallel arm resonator connected to a ground terminal. The second path includes a grounded resonator and is connected in parallel with any of the at least one ladder filter circuit. One end of the capacitor is connected to the second path, and the other end of the capacitor is connected to a third path which connects the parallel arm resonator and the ground terminal.

Abstract: An elastic wave device includes a piezoelectric thin film, IDT electrodes on the piezoelectric thin film, an insulating layer surrounding the piezoelectric thin film on a primary surface of a support substrate, a spacer layer surrounding the piezoelectric thin film in plan view, and a cover on the spacer layer. The spacer layer includes an outer edge and an inner edge closer than the outer edge to the piezoelectric thin film in plan view. The primary surface of the insulating layer closer to the spacer layer includes a sloping region that extends where the insulating layer overlaps the spacer layer in plan view and in which the distance from the first primary surface of the support substrate along the direction perpendicular or substantially perpendicular to the support substrate increases from the outer edge toward the inner edge.

Abstract: Embodiments of this disclosure relate to multiplexers that include acoustic wave filters for filtering radio frequency signals. In certain embodiments, a multiplexer includes a first acoustic wave filter including bulk acoustic wave resonators and a second acoustic wave filter including multilayer piezoelectric substrate surface acoustic wave resonators. The second acoustic wave filter can have a second pass band that is above a first pass band of the first acoustic wave filter. Related acoustic filter assemblies, packaged radio frequency modules, wireless communication devices, and methods are disclosed.

Abstract: A multiplexer includes: first and second substrates overlapping with each other with an air gap interposed therebetween; a first filter disposed on the first substrate and including first series resonators connected in series with a first path, and first parallel resonators; and a second filter disposed on the second substrate and including second series resonators connected in series with a second path, and second parallel resonators connected between the second path and a ground, each of the second series resonators and the second parallel resonators including a piezoelectric film, a first electrode interposed between the piezoelectric film and the second substrate, a second electrode interposed between the piezoelectric film and the air gap, and a resonance region, in at least one second parallel resonator, the first electrode being coupled to the second path, the second electrode being coupled to the ground, the resonance region overlapping with the first path.

Abstract: A bonded body includes a supporting substrate, a piezoelectric material substrate of a material selected from the group consisting of lithium niobate, lithium tantalate and lithium niobate-lithium tantalate, and a bonding layer bonding the supporting substrate and piezoelectric material substrate. A material of the bonding layer is silicon oxide. Provided that the bonding layer is divided into a piezoelectric material substrate-side bonding part and a supporting substrate-side bonding part, the piezoelectric material substrate-side bonding part has a nitrogen concentration higher than a nitrogen concentration of the supporting substrate-side bonding part.

Abstract: A filter device includes a filter between an input/output terminal and an input/output terminal, and an additional circuit connected in parallel with the filter. The filter includes at least two acoustic wave resonators defining a pass band of the filter. The additional circuit includes a longitudinally coupled resonator, and a capacitor connected between the longitudinally coupled resonator and the input/output terminal. A capacitance of a comb-shaped capacitance electrode of the capacitor is smaller than a capacitance of an IDT electrode of at least one acoustic wave resonator of the at least two acoustic wave resonators, and an area of the comb-shaped capacitance electrode of the capacitor is smaller than an area of the IDT electrode of the at least one acoustic wave resonator.

Abstract: A TE20 launch guidance waveguide hybrid coupler includes a waveguide body, a cavity, a plurality of ports, and a bend along the H-plane. The waveguide body includes a hybrid center portion which is disposed between and is in direct communication with the plurality of ports. The bend along the H-Plane is defined within the hybrid center portion, assists in the launching of the TE20 mode, and results in typically half the axial ratio and mass when compared to traditional hybrid approaches.

Abstract: An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate, the IDT electrodes having gap regions, edge regions, and center regions, a first dielectric film having a lower surface disposed on the IDT electrodes and the surface of the substrate, and a material having a density greater than a density of the first dielectric film disposed above the gap regions of the IDT electrodes.

Abstract: A laterally vibrating bulk acoustic wave (LVBAW) resonator includes a piezoelectric plate sandwiched between first and second metal layers. The second metal layer is patterned into an interdigital transducer (IDT) with comb-shaped electrodes having interlocking fingers. The width and pitch of the fingers of the electrodes determine the resonant frequency. A combined thickness of the first and second metal layers and the piezoelectric layer is less than the pitch of the interlocking fingers.

Abstract: An acoustic wave device includes a substrate, a functional element provided on the substrate, a cover layer provided on or above the substrate to cover the functional element, and a protection layer that covers the cover layer. The cover layer includes a curved portion that is curved to protrude outward. A hollow space is defined between the curved portion and the substrate, and the functional element is provided in the hollow space. The acoustic wave device also includes a conductive portion that is provided between the curved portion and the protection layer and extends along a surface of the curved portion.

Abstract: 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.

Abstract: In an acoustic wave device, an interdigital transducer electrode is disposed on a piezoelectric substrate with a reverse velocity surface having an elliptic shape, and a dielectric film is disposed to cover the interdigital transducer electrode. Assuming an electrode density (%) of the interdigital transducer electrode to be y (%) and a wavelength-normalized film thickness 100h/? (%) of the interdigital transducer electrode to be x (%), the wavelength-normalized film thickness x of the interdigital transducer electrode takes a value not less than x satisfying y=0.3452x2?6.0964x+36.262 depending on the electrode density of the interdigital transducer electrode.