In a SAW element, a piezoelectric layer is laid over a support substrate. An IDT electrode includes a main region and two end regions on two sides of the main region. The end region continues from a portion where electrode finger design is modified up to the end part. A resonance frequency determined by electrode finger design of reflector electrode fingers is lower than a resonance frequency determined by electrode finger design of electrode fingers in the main region. An interval between centers of the electrode fingers in the main region is defined as “a”. Number of electrode fingers configuring the end region is defined as “m”. A distance between a center of an electrode finger among the electrode fingers in the main region which is located on a side closest to the end region and a center of a reflector electrode finger among the reflector electrode fingers which is located on a side closest to the end region is defined as “x”. At this time, the following relationship is satisfied:

0.5×a×(m+1)<x<a×(m+1)

A SAW element configured to suppress spurious emissions resulting from non-periodicity of an IDT electrode finger arrangement. In one example, the SAW element is a resonator comprising an IDT electrode including a first plurality of IDT electrode fingers connected to a first busbar and a second plurality of IDT electrode fingers connected to a second busbar, and reflectors having a plurality of reflector fingers. The pluralities of first and second IDT electrode fingers are alternatively connected to each busbar by either normal connections or reversed connections and include regions arranged by at least two different types of pitches. The normal connections are such that either the odd-numbered or even-numbered IDT electrode fingers connect to the first busbar, and the reversed connections are such that the opposite group of IDT electrode fingers connect to the first busbar.

A band elimination filter includes a plurality of parallel resonators, each including a piezoelectric substrate and an IDT electrode on a surface of the piezoelectric substrate. The IDT electrode includes a pair of comb-shaped electrodes opposing each other, and the IDT electrode includes electrode fingers, a pitch of the electrode fingers being different between an end portion of the IDT electrode in a propagation direction of an elastic wave and a central portion of the IDT electrode different from the end portion.

An acoustic wave filter device includes a first band pass filter including a first acoustic wave resonator connected between an antenna terminal and a first signal terminal and having a first pass band, and a second band pass filter connected with the antenna terminal and having a second pass band on a higher side of the first pass band. The first acoustic wave resonator includes a substrate on a surface of which a piezoelectric thin film is provided, an IDT electrode provided on the substrate, and reflectors. At least a pitch of some electrode fingers is different from a pitch of other electrode fingers in at least one of the IDT electrode and the reflectors of the first acoustic wave resonator on a side closest to the antenna terminal.

A SAW element configured to suppress spurious emissions resulting from non-periodicity of an IDT electrode finger arrangement. In one example, the SAW element is a resonator comprising an IDT electrode including a first plurality of IDT electrode fingers connected to a first busbar and a second plurality of IDT electrode fingers connected to a second busbar, and reflectors having a plurality of reflector fingers. The pluralities of first and second IDT electrode fingers are alternatively connected to each busbar by either normal connections or reversed connections and include regions arranged by at least two different types of pitches. The normal connections are such that either the odd-numbered or even-numbered IDT electrode fingers connect to the first busbar, and the reversed connections are such that the opposite group of IDT electrode fingers connect to the first busbar.

A SAW element configured to suppress spurious emissions resulting from non-periodicity of an IDT electrode finger arrangement. In one example, the SAW element is a resonator comprising an IDT electrode including a first plurality of IDT electrode fingers connected to a first busbar and a second plurality of IDT electrode fingers connected to a second busbar, and reflectors having a plurality of reflector fingers. The pluralities of first and second IDT electrode fingers are alternatively connected to each busbar by either normal connections or reversed connections and include regions arranged by at least two different types of pitches. The normal connections are such that either the odd-numbered or even-numbered IDT electrode fingers connect to the first busbar, and the reversed connections are such that the opposite group of IDT electrode fingers connect to the first busbar.

An elastic wave device includes IDT electrodes stacked on a piezoelectric thin film. The IDT electrode includes a plurality of first electrode fingers and a plurality of second electrode fingers. A line connecting the distal ends of the first electrode fingers or the distal ends of the second electrode fingers extends obliquely with respect to a propagation direction of an elastic wave at an oblique angle . The oblique angle is about 0.4 or more and about 10 or less.

An acoustic wave filter device includes a first band pass filter including a first acoustic wave resonator connected between an antenna terminal and a first signal terminal and having a first pass band, and a second band pass filter connected with the antenna terminal and having a second pass band on a higher side of the first pass band. The first acoustic wave resonator includes a substrate on a surface of which a piezoelectric thin film is provided, an IDT electrode provided on the substrate, and reflectors. At least a pitch of some electrode fingers is different from a pitch of other electrode fingers in at least one of the IDT electrode and the reflectors of the first acoustic wave resonator on a side closest to the antenna terminal.

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.

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.