Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers arranged to suppress a spurious response due to shear horizontal mode of the multi-mode surface acoustic wave filter. For example, the acoustic reflector fingers can include stepped lengths and/or slanted pitches to suppress the spurious response due to shear horizontal mode.

A longitudinally coupled resonator acoustic wave filter includes a piezoelectric substrate, IDT electrodes on the piezoelectric substrate along an acoustic wave propagation direction, and a pair of reflectors on the piezoelectric substrate on both sides of the IDT electrodes in the acoustic wave propagation direction. Each of the reflectors includes first and second reflector busbars, and first reflective electrode fingers connected to at least one of the first reflector busbar and the second reflector busbar. The reflector includes a first portion in which lengths of the first reflective electrode fingers change in the acoustic wave propagation direction.

Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and stepped acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers with stepped lengths.

Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and slanted acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers with slanted pitches.

Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and stepped acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers with stepped lengths.

Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and slanted acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers with slanted pitches.

Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers arranged to suppress a spurious response due to shear horizontal mode of the multi-mode surface acoustic wave filter. For example, the acoustic reflector fingers can include stepped lengths and/or slanted pitches to suppress the spurious response due to shear horizontal mode.

Multi-mode surface acoustic wave filters are disclosed. A multi-mode surface acoustic wave filter can include a plurality of interdigital transducer electrodes that are longitudinally coupled to each other and stepped acoustic reflectors on opposing sides of the plurality of interdigital transducer electrodes. The acoustic reflectors include acoustic reflector fingers with stepped lengths.

A longitudinally coupled resonator acoustic wave filter includes a piezoelectric substrate, IDT electrodes on the piezoelectric substrate along an acoustic wave propagation direction, and a pair of reflectors on the piezoelectric substrate on both sides of the IDT electrodes in the acoustic wave propagation direction. Each of the reflectors includes first and second reflector busbars, and first reflective electrode fingers connected to at least one of the first reflector busbar and the second reflector busbar. The reflector includes a first portion in which lengths of the first reflective electrode fingers change in the acoustic wave propagation direction.

An acoustic wave device includes acoustic wave resonators each including a piezoelectric substrate including a piezoelectric body layer, and an IDT electrode on the piezoelectric substrate and including electrode fingers. At least one of the acoustic wave resonators is an excitation angle change resonator, in which, the piezoelectric body layer includes a propagation axis and the electrode fingers are curved. In the excitation angle change resonator, an excitation direction of an acoustic wave in a portion of one of the electrode fingers is one of first, second, or third directions. An excitation angle of the excitation angle change resonator is not uniform in the IDT electrode.