Abstract: An acoustic wave filter includes a substrate having piezoelectricity, input/output terminals on the substrate, ground terminals on the substrate and separated from each other, and a longitudinally coupled resonator on the substrate and arranged on a path connecting the input/output terminals, in which each of IDT electrodes included in the longitudinally coupled resonator includes a pair of comb-shaped electrodes each of which is provided with a plurality of electrode fingers and a busbar electrode, the other of the pair of the comb-shaped electrodes included in the IDT electrode arranged at a position closest to the input/output terminal is connected to the ground terminal on the substrate, and the other of the pair of comb-shaped electrodes included in each of all the IDT electrodes other than the IDT electrode is connected to the ground terminal on the substrate.

Abstract: An elastic wave filter apparatus includes a transmission-side filter, a reception-side filter, an antenna terminal, and a matching circuit. The matching circuit is connected between a common node of the transmission-side filter and the reception-side filter and the antenna terminal. The transmission-side filter includes a ladder circuit and filter inductors. The matching circuit includes a matching inductor. The ladder circuit includes series arm resonators and parallel arm resonators. The matching inductor is connected between a transmission line connecting the common node and the antenna terminal and a first terminal of the filter inductor on the side of the parallel arm resonator.

Abstract: An acoustic wave filter includes a substrate having piezoelectricity, input/output terminals on the substrate, ground terminals on the substrate and separated from each other, and a longitudinally coupled resonator on the substrate and arranged on a path connecting the input/output terminals, in which each of IDT electrodes included in the longitudinally coupled resonator includes a pair of comb-shaped electrodes each of which is provided with a plurality of electrode fingers and a busbar electrode, the other of the pair of the comb-shaped electrodes included in the IDT electrode arranged at a position closest to the input/output terminal is connected to the ground terminal on the substrate, and the other of the pair of comb-shaped electrodes included in each of all the IDT electrodes other than the IDT electrode is connected to the ground terminal on the substrate.

Abstract: An elastic wave filter apparatus includes a transmission-side filter, a reception-side filter, an antenna terminal, and a matching circuit. The matching circuit is connected between a common node of the transmission-side filter and the reception-side filter and the antenna terminal. The transmission-side filter includes a ladder circuit and filter inductors. The matching circuit includes a matching inductor. The ladder circuit includes series arm resonators and parallel arm resonators. The matching inductor is connected between a transmission line connecting the common node and the antenna terminal and a first terminal of the filter inductor on the side of the parallel arm resonator.