An acoustic wave device includes a piezoelectric layer and first and second electrodes. The piezoelectric layer is made of lithium niobate or lithium tantalate. The first electrode and the second electrode oppose each other in a direction intersecting with a thickness direction of the piezoelectric layer. The first electrode and the second electrode are electrodes adjacent to each other. d/p is about 0.5 or smaller, where d is a thickness of the piezoelectric layer and p is a center-to-center distance between the first electrode and the second electrode. An intersecting width is about 4.6p or greater. The intersecting width is a dimension of a region where the first electrode and the second electrode oppose each other. The direction of the dimension is an extending direction of the first electrode and the second electrode.

An interdigital transducer electrode that is provided on a piezoelectric film includes a first busbar, a second busbar, multiple first electrode fingers, and multiple second electrode fingers. The first electrode fingers and the second electrode fingers overlap in a region in a direction in which an acoustic wave propagates, and the region includes a central region, a first edge region that is located between the central region and the first busbar, and a second edge region that is located between the central region and the second busbar. An acoustic velocity in the first edge region and the second edge region is lower than an acoustic velocity in the central region. An acoustic velocity in a busbar region is higher than the acoustic velocity in the central region.

In an acoustic wave device, a piezoelectric body is directly or indirectly provided on a high acoustic velocity material layer, an interdigital transducer electrode is directly or indirectly provided on the piezoelectric body, the interdigital transducer electrode includes a first busbar, a second busbar spaced away from the first busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers, and a weighting is applied to the interdigital transducer electrode by providing a floating electrode finger not electrically connected to the first busbar or the second busbar or applied by providing an electrode finger formed by metallizing a gap between the first electrode fingers or a gap between the second electrode fingers to integrate the first electrode fingers or the second electrode fingers.

An acoustic wave filter includes a divided resonator group and series arm resonators in a path connecting an input-output terminal and an input-output terminal to each other and parallel arm resonators each between a node in the path described above and the ground. The divided resonator group, the series arm resonators, and the parallel arm resonators each include an acoustic wave resonator including an interdigital transducer electrode on a piezoelectric substrate. The divided resonator group includes divided resonators coupled in series with each other. The IDT electrode included in the divided resonator includes a first withdrawal electrode. The IDT electrode included in the divided resonator includes a second withdrawal electrode different from the first withdrawal electrode with respect to the electrode finger structure.

An acoustic wave filter includes series arm resonators each including an IDT electrode on a piezoelectric substrate. Resonant frequencies of the series arm resonators are positioned within the pass band of the acoustic wave filter. The IDT electrode includes a pair of comb-shaped electrodes. Each of the comb-shaped electrodes includes electrode fingers and a busbar electrode. The electrode fingers extend in a direction intersecting a propagation direction of acoustic waves and are parallel with each other. One end of an electrode finger and one end of another electrode finger are connected with each other by the busbar electrode. The IDT electrode of the series arm resonator with the lowest anti-resonant frequency includes two or more withdrawal-weighted floating electrodes without any of the electrode fingers of one of the comb-shaped electrodes interposed therebetween.

An acoustic wave filter includes at least one serial arm resonance circuit on a path connecting input/output terminals, and at least one parallel arm resonance circuit between a node on the path and a ground, in which each of the at least one serial arm resonance circuit and the at least one parallel arm resonance circuit includes an acoustic wave resonator, a first parallel arm resonance circuit of the at least one parallel arm resonance circuit includes a bridging capacitor connected in parallel to the acoustic wave resonator, an anti-resonant frequency of the first parallel arm resonance circuit is positioned on a higher-frequency side than the pass band, and a resonant frequency of a first serial arm resonance circuit of the at least one serial arm resonance circuit is positioned on a lower-frequency side than the anti-resonant frequency of the first parallel arm resonance circuit.

An extractor includes a band pass filter and a band elimination filter. In the band pass filter, an IDT electrode in at least one of a first series arm resonator and a first parallel arm resonator that are arranged at a series arm and a parallel arm, respectively, closest to a common terminal is a first IDT electrode in which neither a plurality of first electrode fingers nor a plurality of second electrode fingers is partially missing, and an IDT electrode in at least one of the first series arm resonator or the first parallel arm resonator that does not include the first IDT electrode, second series arm resonators, and second parallel arm resonators is a second IDT electrode in which at least one of a plurality of electrode fingers and a plurality of second electrode fingers is partially missing.

An acoustic wave resonator includes an IDT electrode that is on or above a piezoelectric plate and includes a periodic withdrawal weighted portion in each of a plurality of regions for at least two or more periods in an acoustic wave propagation direction. A periodic withdrawal weighted portion in at least one of the regions is different from a periodic withdrawal weighted portion in at least one of the other regions.

An acoustic wave resonator includes an IDT electrode that is on or above a piezoelectric plate and includes a periodic withdrawal weighted portion in each of a plurality of regions for at least two or more periods in an acoustic wave propagation direction. A periodic withdrawal weighted portion in at least one of the regions is different from a periodic withdrawal weighted portion in at least one of the other regions.

An acoustic wave filter includes series arm resonators each including an IDT electrode on a piezoelectric substrate. Resonant frequencies of the series arm resonators are positioned within the pass band of the acoustic wave filter. The IDT electrode includes a pair of comb-shaped electrodes. Each of the comb-shaped electrodes includes electrode fingers and a busbar electrode. The electrode fingers extend in a direction intersecting a propagation direction of acoustic waves and are parallel with each other. One end of an electrode finger and one end of another electrode finger are connected with each other by the busbar electrode. The IDT electrode of the series arm resonator with the lowest anti-resonant frequency includes two or more withdrawal-weighted floating electrodes without any of the electrode fingers of one of the comb-shaped electrodes interposed therebetween.