An acoustic wave device includes a multilayer substrate including a reverse-velocity surface, a piezoelectric film, a low acoustic velocity material layer, a high acoustic velocity material layer, and an IDT electrode disposed on the piezoelectric film. In the IDT electrode, gap lengths of a first gap between a tip of each of first electrode fingers and a second busbar and a second gap between a tip of each of second electrode fingers and a first busbar are about 0.23λ or shorter, the gap lengths extending in an extension direction of the first and second electrode fingers.

The present invention relates to a transducer structure with transverse mode suppression means, in particular for a single-port resonator, comprising a piezoelectric substrate (120, 170), at least a pair of inter-digitated comb electrodes (102, 112) formed on the piezoelectric substrate (120, 170), wherein the first comb electrode (102) comprises a first bus bar (108) and a plurality of electrode fingers (104) alternating with shorter dummy electrode fingers (106), both extending from the first bus bar (108), wherein the second comb electrode (112) comprises a second bus bar (118) and a plurality of electrode fingers (114) extending from the second bus bar (118), wherein the dummy electrode fingers (106) of the first bus bar (108) face the electrode fingers (114) of the second bus bar (118) and are separated from the electrode fingers (114) by first gaps (110a), characterized in further comprising a transverse mode suppression layer (122, 132, 222, 232, 422, 432) provided partially underneath the first gap (110a) and chosen such that the phase velocity of a guided wave is smaller in the region of the transverse mode suppression layer (122, 132, 222, 232, 422, 432) compared to the phase velocity of the guided wave in the central region (136) underneath the alternating electrodes fingers (104, 114) of the first and second electrodes (102, 112). The present invention also relates to a method for fabricating the transducer structure as previously described and to a single-port resonator comprising at least one structure as previously described.

An acoustic wave device includes a substrate including a piezoelectric layer, first and second resonators on the substrate, and a shared reflector. The second resonator is located on the substrate adjacent to the first resonator and has different frequency characteristics than the first resonator. The shared reflector is located on the substrate between the first resonator and the second resonator and is a reflector for both the first resonator and the second resonator. The first resonator includes a first interdigital transducer electrode with electrode fingers positioned with a first pitch. The second resonator includes a second interdigital transducer electrode with electrode fingers positioned with a second pitch. A lower limit frequency of a stop band of the shared reflector is between a lower limit frequency of a stop band of the first resonator and a lower limit frequency of a stop band of the second resonator. An upper limit frequency of the stop band of the shared reflector is between an upper limit frequency of the stop band of the first resonator and an upper limit frequency of the stop band of the second resonator.

A longitudinally coupled resonator elastic wave filter is disposed on a piezoelectric substrate. IDT electrodes include first and second busbars. An inorganic insulating layer is provided on at least one side in a direction perpendicular or substantially perpendicular to an elastic wave propagation direction to cover the first or second busbars, and a first wiring line is disposed on the inorganic insulating layer to extend in the elastic wave propagation direction. A second wiring line three-dimensionally crosses the first wiring line with the inorganic insulating layer interposed therebetween. The first wiring line is connected to busbars, which are connected to the same potential, by extending through the inorganic insulating layer.

A micro-resonator includes a first electrode positioned on a piezoelectric plate at a first end of the piezoelectric plate, the first electrode including a first set of fingers and a second electrode positioned on the piezoelectric plate at a second end of the piezoelectric plate. The second electrode including a second set of fingers interdigitated with the first set of fingers with an overlapping distance without touching the first set of fingers, the overlapping distance being less than seven-tenths the length of one of the first set of fingers or the second set of fingers. At least one of the first end or the second end of the piezoelectric plate may define a curved shape.

An acoustic wave filter device includes at least one series arm resonator and a parallel arm resonator. The series arm resonators and the parallel arm resonator are defined by acoustic wave resonators, an interdigital transducer electrode of the series arm resonators is an apodized interdigital transducer electrode subjected to apodization weighting, in the interdigital transducer electrode of the parallel arm resonator, an intersecting portion includes a central region and low acoustic velocity regions provided at both outer side portions of the central portion, an acoustic velocity of an acoustic wave in the low acoustic velocity region is lower than an acoustic velocity of an acoustic wave in the central region, and a high acoustic velocity region where an acoustic velocity of an acoustic wave is higher than that of the low acoustic velocity region is provided at an outer side portion of each of the low acoustic velocity regions.

An elastic wave device includes a wiring board, a device chip having a resonator, and a wiring pattern electrically connected to the resonator, the device chip is electrically connected to the wiring board, and a sealing portion that seals the device chip. The wiring pattern includes a first wiring layer and a second wiring layer. The second wiring layer includes a lower metal layer in contact with an upper surface of the first wiring layer, a partition layer which is a metal layer in contact with an upper surface of the lower metal layer, and an upper metal layer in contact with an upper surface of the partition layer. The partition layer is a metal having a lower electrical conductivity than the lower metal layer and the upper metal layer.

An acoustic wave device is disclosed. The acoustic waved device can be a shear horizontal mode surface acoustic wave device. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode over the piezoelectric layer, and a temperature compensation layer over the interdigital transducer electrode. The piezoelectric layer can be a lithium niobate layer with a cut angle in a range of −20° YX to 25° YX. The interdigital transducer electrode includes a first layer having a first thickness and a second layer having a second thickness. The first layer affects acoustic properties of the acoustic wave device and the second layer affects electrical properties of the acoustic wave device. The first layer is positioned between the piezoelectric layer and the second layer. The first thickness is configured such that a frequency response of the acoustic wave device includes a Rayleigh mode response at a frequency higher than a shear horizontal mode response resonance. The first thickness can be greater than the second thickness.

An elastic wave device includes a piezoelectric film laminated on a first main surface of a support substrate including a recessed portion open to a first main surface. A cavity portion including the recessed portion is defined by the support substrate and the piezoelectric film. An electrode is on the piezoelectric film. The electrode includes first and second bus bars, a first electrode finger connected to the first bus bar, and a second electrode finger connected to the second bus bar. The first and second bus bars include corner portions inside the cavity portion when viewed in plan view. A curved portion as a pressure relaxation portion to relax pressure on the piezoelectric film at at least one of the corner portions of the first and second bus bars is provided between the corner portion and an outer edge of the cavity portion.

A front-end module may include an acoustic wave filter with a first and second interdigital transducer electrode. The first interdigital transducer electrode may be single-ended with a first input bus bar that receives an input signal and a second input bus bar connected to ground. The second interdigital transducer electrode may be differential with a first output bus bar connected to a first output terminal and a second output bus bar connected to a second output terminal. The front-end module may include a low noise amplifier (LNA) that outputs a differential signal via a differential output and has a differential input connected to the acoustic wave filter. The LNA may include a first input transistor that receives a first signal from the first output terminal of the acoustic wave filter and a second input transistor that receives a second signal from the second output terminal of the acoustic wave filter.