Abstract: An acoustic wave element includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate, and a reflector. The IDT electrode includes plural electrode fingers, and the reflector includes plural reflector electrode fingers. In a case where IRGAP is an IDT-reflector gap that is a distance between a center of the electrode finger located closest to the reflector and a center of the reflector electrode finger located closest to the IDT electrode, and ?REF is a reflector wave length that is twice a repetition pitch of the reflector electrode fingers, a ratio of about 0.25?IRGAP/?REF?about 0.44 is satisfied, and the reflector wave length is longer than an IDT wave length that is a repetition pitch of the electrode fingers.

Abstract: An acoustic wave element includes an electrode-finger pitch of reflecting-electrode fingers greater than an electrode-finger pitch pi of comb-shaped electrode fingers, and a center-to-center distance between a reflecting-electrode finger and a comb-shaped electrode finger is equal to or less than about 0.9 times the electrode-finger pitch of the reflecting-electrode fingers.

Abstract: An acoustic wave element includes IDT electrodes on two main surfaces of a piezoelectric layer, and reflectors on both of the two main surfaces. The IDT electrodes each include electrode fingers extending in a second direction that intersects a first direction. The reflectors each include reflection electrode fingers extending in the second direction. An array pitch of the electrode fingers along the first direction is Pi, an array pitch of the reflection electrode fingers is Pr, and an IDT-reflector gap in the first direction d1 between a center of an electrode finger and a center of a reflection electrode finger that is closest to the IDT electrode among the plurality of reflection electrode fingers is G, a thickness of the piezoelectric layer is smaller than or equal to twice Pi, G is smaller than Pr, and Pr is greater than Pi.

Abstract: An acoustic wave element includes a piezoelectric substrate, an IDT electrode including comb electrode fingers, and a reflector including reflective electrode fingers. An average value of all pitches of the comb electrode fingers is smaller than an average value of all pitches of the reflective electrode fingers. When a total number of the comb electrode fingers is defined as N, at least one n-th end-side pitch satisfying 1?n?(0.233×N) is smaller than the average value of all the pitches of the comb electrode fingers.

Abstract: In an acoustic wave element, a distance between a comb electrode finger closest to a reflector and a reflective electrode finger closest to an interdigital transducer (IDT) electrode is set as an IDT-reflector gap. An inter-center distance between adjacent electrode fingers is set as a pitch. The electrode fingers in a direction from the comb electrode finger closest to the reflector toward a center are sequentially set as an n-th end-side electrode finger, and a pitch between the n-th end-side electrode finger and an (n+1)-th end-side electrode finger is set as an n-th end-side pitch. An average value of each pitch by all the comb electrode fingers is set as an average IDT pitch, and an average value of each pitch by the reflective electrode fingers is set as an average reflector pitch.

Abstract: An acoustic wave element includes a piezoelectric substrate, an IDT electrode including comb electrode fingers, and a reflector including reflective electrode fingers. An average value of all pitches of the comb electrode fingers is smaller than an average value of all pitches of the reflective electrode fingers. When a total number of the comb electrode fingers is defined as N, at least one n-th end-side pitch satisfying 1?n?(0.233×N) is smaller than the average value of all the pitches of the comb electrode fingers.

Abstract: In an acoustic wave element, a distance between a comb electrode finger closest to a reflector and a reflective electrode finger closest to an interdigital transducer (IDT) electrode is set as an IDT-reflector gap. An inter-center distance between adjacent electrode fingers is set as a pitch. The electrode fingers in a direction from the comb electrode finger closest to the reflector toward a center are sequentially set as an n-th end-side electrode finger, and a pitch between the n-th end-side electrode finger and an (n+1)-th end-side electrode finger is set as an n-th end-side pitch. An average value of each pitch by all the comb electrode fingers is set as an average IDT pitch, and an average value of each pitch by the reflective electrode fingers is set as an average reflector pitch.

Abstract: An acoustic wave filter device includes a first longitudinally coupled acoustic wave resonator including an odd number of first IDT electrodes arranged along an acoustic wave propagation direction and a second longitudinally coupled acoustic wave resonator including an odd number of second IDT electrodes arranged in the acoustic wave propagation direction. Among the first IDT electrodes, the odd-numbered IDT electrodes are connected to a node and the even-numbered IDT electrodes are connected to a node. Among the second IDT electrodes, the odd-numbered IDT electrodes are connected to the node and the even-numbered IDT electrodes are connected to the node. The number of first IDT electrodes connected to the node and the number of second IDT electrodes connected to the node are the same.

Abstract: An acoustic wave element includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate, and a reflector. The IDT electrode includes plural electrode fingers, and the reflector includes plural reflector electrode fingers. In a case where IRGAP is an IDT-reflector gap that is a distance between a center of the electrode finger located closest to the reflector and a center of the reflector electrode finger located closest to the IDT electrode, and ?REF is a reflector wave length that is twice a repetition pitch of the reflector electrode fingers, a ratio of about 0.25?IRGAP/?REF?about 0.44 is satisfied, and the reflector wave length is longer than an IDT wave length that is a repetition pitch of the electrode fingers.

Abstract: An acoustic wave element includes an electrode-finger pitch of reflecting-electrode fingers greater than an electrode-finger pitch pi of comb-shaped electrode fingers, and a center-to-center distance between a reflecting-electrode finger and a comb-shaped electrode finger is equal to or less than about 0.9 times the electrode-finger pitch of the reflecting-electrode fingers.

Abstract: An acoustic wave filter device includes a first longitudinally coupled acoustic wave resonator including an odd number of first IDT electrodes arranged along an acoustic wave propagation direction and a second longitudinally coupled acoustic wave resonator including an odd number of second IDT electrodes arranged in the acoustic wave propagation direction. Among the first IDT electrodes, the odd-numbered IDT electrodes are connected to a node and the even-numbered IDT electrodes are connected to a node. Among the second IDT electrodes, the odd-numbered IDT electrodes are connected to the node and the even-numbered IDT electrodes are connected to the node. The number of first IDT electrodes connected to the node and the number of second IDT electrodes connected to the node are the same.

Abstract: A multiplexer includes a first filter which is a receive filter using acoustic waves and whose pass band is a first frequency band, a second filter whose pass band is a second frequency band, and a third filter whose pass band is a third frequency band. The first filter includes a ladder circuit including serial arm resonators and multiple parallel arm circuits. A parallel arm resonator is included in at least one of the multiple parallel arm circuits except the parallel arm circuit. The parallel arm circuit is connected at the position closest to a common terminal. At least one of the frequencies expressed by ±M×f1±N×f2 is included in the third frequency band, and the resonant frequency of the parallel arm resonator is included in the third frequency band.

Abstract: A filter device includes a first ladder filter including serial resonators disposed in a terminal-to-terminal path and parallel resonators disposed in connection paths, a first acoustic wave resonator disposed in parallel to the parallel resonator, and a second acoustic wave resonator disposed in parallel to the serial resonator. Resonance points and anti-resonance points of the first and second acoustic wave resonators are both positioned on the lower frequency side or the higher frequency side of a pass band of the first ladder filter, and on the same side of the pass band of the first ladder filter, when viewed from the pass band of the first filter.

Abstract: An elastic wave apparatus includes a piezoelectric substrate, a first dielectric film provided on the piezoelectric substrate, an IDT electrode provided on the first dielectric film, and a capacitor that includes a pair of comb-shaped electrodes provided directly on the piezoelectric substrate and is electrically connected to the IDT electrode. An elastic wave resonator including the IDT electrode is provided.

Abstract: An acoustic wave element includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate, and a reflector. The IDT electrode includes plural electrode fingers, and the reflector includes plural reflector electrode fingers. An IDT-reflector gap that is a distance between a center of the electrode finger located closest to the reflector and a center of the reflector electrode finger located closest to the IDT electrode is not more than about 0.45 times an IDT wave length as a repetition pitch of the electrode fingers, and a reflector wave length that is twice a repetition pitch of the reflector electrode fingers is longer than the IDT wave length.

Abstract: A filter device includes an antenna terminal to be connected to an antenna, first inductors connected between the antenna terminal and a ground potential and defined by parallel divided inductors, and first and second acoustic wave filters commonly connected to the antenna terminal and including second inductors, respectively. The first inductors and the second inductors are electromagnetically coupled to each other mainly in a one-to-one relationship.

Abstract: An elastic wave device includes first and second longitudinally coupled resonator elastic wave elements aligned on a piezoelectric substrate. A second reflector of the first longitudinally coupled resonator elastic wave element and a third reflector of the second longitudinally coupled resonator elastic wave element are adjacent to each other in an elastic wave propagation direction. A ground interconnection extends in a direction intersecting with the elastic wave propagation direction and in a region between the second reflector and the third reflector. A gap in one portion of the ground interconnection includes a different acoustic velocity portion where an acoustic velocity is different from an acoustic velocity in another portion of the ground interconnection.

Abstract: A filter device includes a first ladder filter including serial resonators disposed in a terminal-to-terminal path and parallel resonators disposed in connection paths, a first acoustic wave resonator disposed in parallel to the parallel resonator, and a second acoustic wave resonator disposed in parallel to the serial resonator. Resonance points and anti-resonance points of the first and second acoustic wave resonators are both positioned on the lower frequency side or the higher frequency side of a pass band of the first ladder filter, and on the same side of the pass band of the first ladder filter, when viewed from the pass band of the first filter.

Abstract: A filter device includes an antenna terminal to be connected to an antenna, first inductors connected between the antenna terminal and a ground potential and defined by parallel divided inductors, and first and second acoustic wave filters commonly connected to the antenna terminal and including second inductors, respectively. The first inductors and the second inductors are electromagnetically coupled to each other mainly in a one-to-one relationship.

Abstract: An elastic wave apparatus includes a piezoelectric substrate, a first dielectric film provided on the piezoelectric substrate, an IDT electrode provided on the first dielectric film, and a capacitor that includes a pair of comb-shaped electrodes provided directly on the piezoelectric substrate and is electrically connected to the IDT electrode. An elastic wave resonator including the IDT electrode is provided.