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 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 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.

A multiplexer includes a common terminal, first and second transmit filters, and a first receive filter connected to the common terminal and each including resonators, a relationship Tx1c < Rx1c < Tx2c is satisfied, where Tx1c, Tx2c, and Rx1c denote center frequencies of pass bands Tx1, Tx2, and Tx3 of the first and second transmit filters and the first receive filter, respectively, a resonator closest to the common terminal in the first receive filter is a series arm resonator, and a pitch ratio denoted by pS1(Rx1)/p(Tx2) is more than about 1 and less than or equal to about 1.035, where p(Tx2) denotes an electrode finger pitch of an IDT electrode in a resonator closest to the common terminal in the second transmit filter and pS1(Rx1) denotes an electrode finger pitch of an IDT electrode of the series arm resonator closest to the common terminal in the first receive filter.

A multiplexer includes a common terminal, a first terminal, a second terminal, a first filter device including acoustic wave resonators including series resonators and parallel resonators, an inductor provided between an acoustic wave resonator and the first terminal, and a second filter device. The first filter device further includes a first ground terminal to which a parallel resonator is electrically connected, a second ground terminal to which the parallel resonators are electrically connected, and a wiring provided between the inductor and an acoustic wave resonator. In the first filter device, the wiring is electrically connected to the first ground terminal, and the first ground terminal is not connected to the second ground terminal.

A multiplexer includes a common terminal, a first terminal, a second terminal, a first filter device including acoustic wave resonators including series resonators and parallel resonators, an inductor provided between an acoustic wave resonator and the first terminal, and a second filter device. The first filter device further includes a first ground terminal to which a parallel resonator is electrically connected, a second ground terminal to which the parallel resonators are electrically connected, and a wiring provided between the inductor and an acoustic wave resonator. In the first filter device, the wiring is electrically connected to the first ground terminal, and the first ground terminal is not connected to the second ground terminal.

In a radio-frequency module, a conductive layer covers a major surface opposite to the mounting board side of a resin layer and a major surface opposite to the mounting board side of an electronic component. The electronic component includes an electronic component body and a plurality of outer electrodes. The electronic component body includes an electrical insulating portion and a conductive portion provided inside the electrical insulating portion, forming at least a portion of a circuit element of the electronic component. The electronic component body has a third major surface and a fourth major surface opposite to each other, and an outer side surface. The third major surface forms the major surface of the electronic component, and the third major surface is in contact with the conductive layer. The plurality of outer electrodes are provided on the fourth major surface, but are not extended over the third major surface.

Aspects of this disclosure relate to a radio frequency system with an antenna, a radio frequency amplifier, and parallel acoustic wave filters. The parallel acoustic wave filters can each be a band pass filter having a passband and resonator area. The passbands of the parallel acoustic filters can be overlap in an overlap band. One of the parallel acoustic wave filters can have a smaller resonator area than another of the parallel acoustic wave filters.

Aspects of this disclosure relate to a radio frequency system with an antenna, a radio frequency amplifier, and parallel acoustic wave filters. The parallel acoustic wave filters can each be a band pass filter having a passband and resonator area. The passbands of the parallel acoustic filters can be overlap in an overlap band. One of the parallel acoustic wave filters can have a smaller resonator area than another of the parallel acoustic wave filters.