An acoustic wave resonator includes: a piezoelectric substrate; and an interdigital transducer (IDT) located on the piezoelectric substrate, the IDT including a pair of comb-shaped electrodes having a plurality of electrode fingers and a bus bar to which the plurality of electrode fingers are coupled, the IDT having: a first region in which a pitch of electrode fingers is substantially constant; a second region in which a pitch of electrode fingers decreases at closer distances to an outer side; and a third region in which a pitch of electrode fingers increases at closer distances to an outer side, the second region being located outside the first region in an arrangement direction of the plurality of electrode fingers, and the third region being located outside the second region in the arrangement direction.

An electronic component includes: a first substrate having a first surface; a second substrate having a second surface facing the first surface across an air gap; a first coil pattern that is located on the first surface so as to face the second surface across the air gap; a second coil pattern that is located in a second region on the second surface and faces the first surface across the air gap, at least a part of the second region overlapping with a first region in plan view, the first region being formed of a region in which the first coil pattern is located and a region surrounded by the first coil pattern; and a connection terminal connecting the first coil pattern and the second coil pattern.

Disclosed herein are embodiments of a ladder-type filter comprising a plurality of series arm resonators and a plurality of parallel arm resonators, at least one of the plurality of series arm resonators including a piezoelectric substrate and an interdigital transducer electrode disposed on the piezoelectric substrate, an aperture W1 of the interdigital transducer electrode being configured to be less than 13λ, where λ is a wavelength of a surface acoustic wave excited by the interdigital transducer electrode. The relationship between the aperture W1 and the wavelength λ can be W1 < 13λ, W1 < 11λ, W1 < 4λ, or W1 > 6λ.

A circuit comprising a receive block, a transmit block, and an antenna multiplexer. The antenna multiplexer includes an input port coupled to the transmit block, an output port coupled to the receive block, a common port for coupling to an antenna, and a receive filter coupled between the common port and the output port. The receive filter includes a first plurality of resonators coupled together in series between the common port and the output port including a compensation resonator coupled directly to the output port. A first angular range of a reflection coefficient of the antenna multiplexer over a transmission frequency band measured looking into the output port of the antenna multiplexer does not overlap with a second angular range of the conjugate of the reflection coefficient of the low noise amplifier over the transmission frequency band measured looking into an input of the low noise amplifier.

A multiplexer includes a first filter and a second filter with a lower pass band than that of the first filter. A longitudinally coupled acoustic wave resonator of the first filter includes an interdigital transducer electrode group of interdigital transducer electrodes having an asymmetric shape with respect to a center line that passes through a center of the interdigital transducer electrode group and is perpendicular or substantially perpendicular to an acoustic wave propagation direction. The interdigital transducer electrodes connected to a first path on a common terminal side when seen from the longitudinally coupled acoustic wave resonator have a smaller aggregate average of electrode finger pitches of the interdigital transducer electrodes and a smaller sum of numbers of pairs of electrode fingers of the interdigital transducer electrodes, compared with the interdigital transducer electrodes connected to the first path on a first terminal side.

Aspects of this disclosure relate to an acoustic wave filter that includes acoustic wave resonators arranged to filter a radio frequency signal. The acoustic wave resonators include a first acoustic wave resonator. The acoustic wave filter includes a circuit element in parallel with the first acoustic wave resonator in a stage of the acoustic wave filter. The circuit element and the first acoustic wave resonator have different resonant frequencies. The circuit element can reduce an impact of bulk mode of the first acoustic wave resonator on insertion loss of the acoustic wave filter. The first acoustic wave resonator can be a surface acoustic wave resonator in certain embodiments. The circuit element can be a second acoustic wave resonator or a capacitor, for example.

Aspects of this disclosure relate to an acoustic wave filter that includes acoustic wave resonators arranged to filter a radio frequency signal. The acoustic wave resonators include a first acoustic wave resonator. The acoustic wave filter includes a circuit element in parallel with the first acoustic wave resonator in a stage of the acoustic wave filter. The circuit element and the first acoustic wave resonator have different resonant frequencies. The circuit element can reduce an impact of bulk mode of the first acoustic wave resonator on insertion loss of the acoustic wave filter. The first acoustic wave resonator can be a surface acoustic wave resonator in certain embodiments. The circuit element can be a second acoustic wave resonator or a capacitor, for example.

Aspects of this disclosure relate to a multiplexer that includes a first filter and a second filter coupled to a common node. The first filter includes an acoustic filter arranged to filter a radio frequency signal, a matching network coupled between the acoustic filter and the common node, and a parallel circuit coupled in series between the acoustic filter and the common node. The parallel circuit includes an inductive component in parallel with a capacitive component. In certain instances, the first filter is coupled to the common node via a switch, the matching network is coupled to a node between the acoustic filter and the switch, and the parallel circuit is coupled in series between the acoustic filter and the switch. Related methods, radio frequency modules, and wireless communication devices are also disclosed.

Aspects of this disclosure relate to an acoustic wave resonator with transverse mode suppression. The acoustic wave resonator can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can be a conductive strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. A layer of the mass loading strip can have a density that is at least as high as a density of a material of the interdigital transducer electrode. The material of the interdigital transducer can impact acoustic properties of the acoustic wave resonator.

The strength of a spurious signal is reduced while maintaining the uniformity of a resonant frequency in an identical elastic wave resonator. An elastic wave resonator (4) includes a piezoelectric body (6), and a plurality of electrode fingers (14, 22) located on the piezoelectric body and arranged in a propagation direction (TD) of an elastic wave. A region in which the plurality of electrode fingers are located includes a first region (24A) and a second region (24B) in a plan view. The plurality of electrode fingers include a first electrode finger group (14A) located in the first region and a second electrode finger group (14B) located in the second region, and a pitch (PA) of the first electrode finger group is different from a pitch (PB) of the second electrode finger group. The first region and the second region have frequency effective-characteristics acting in a direction to cancel out effects on a higher resonant or antiresonant frequency and a lower resonant or antiresonant frequency brought about by a magnitude correlation between the pitches of the first and second electrode finger groups.