Embodiments of this application provide a filter and a method for adjusting performance of a filter, so as to quickly adjust performance of a filter. The filter includes at least two acoustic wave resonators; and a performance adjustment structure, connected to an output end of a first acoustic wave resonator and an input end of a second acoustic wave resonator, where the first acoustic wave resonator and the second acoustic wave resonator are any two of the at least two acoustic wave resonators, the performance adjustment structure includes a capacitor structure and/or an inductor structure, and the performance adjustment structure is configured to adjust an energy coupling mode between the first acoustic wave resonator and the second acoustic wave resonator.

In an acoustic wave element of the present invention, a first imaginary line connecting end portions of the plurality of first electrode fingers in the IDT electrode on the second bus bar side and a second imaginary line connecting end portions of the plurality of second electrode fingers in the IDT electrode on the first bus bar side are within ranges of 2 degrees<A10 degrees and 2 degrees<B10 degrees where an angle formed by the first imaginary line and the propagation direction is the first inclination angle A and an angle formed by the second imaginary line and the propagation direction is the second inclination angle B.

A SAW filter in which a plurality of IDT electrodes is disposed in the propagation direction of a SAW and ground terminals are separated. The present invention has an advantage in that the attenuation effect of the SAW filter is improved. Furthermore, a skirt characteristic on the high frequency side of a transmission stage and a skirt characteristic on the low frequency side of a reception stage can be improved. Furthermore, an equivalent pass band characteristic can be achieved and a skirt characteristic on the high frequency side and a skirt characteristic on the low frequency side can be improved. Furthermore, the number of bridge electrodes can be reduced and thus a process can be simplified because ground terminals are separated.

An acoustic wave device includes a first longitudinally-coupled acoustic wave filter having interdigital transducer (IDT) electrodes arranged in a propagation direction of acoustic wave, and a second longitudinally-coupled acoustic wave filter having IDT electrodes arranged in a propagation direction of acoustic wave. In the IDT electrodes of the first longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an in-phase relation. In the IDT electrodes of the second longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an anti-phase relation. This acoustic wave device has an excellent attenuation characteristic while maintaining a preferable insertion loss.