A multiplexer includes a transmit filter including first acoustic wave resonators connected to a first path between a common terminal and a transmit terminal, one or some first acoustic wave resonators of the first acoustic wave resonators being provided on a first substrate, and a remaining first acoustic wave resonator being provided on a second substrate, and a receive filter including second acoustic wave resonators connected to a second path between the common terminal and a receive terminal, one or some second acoustic wave resonators of the second acoustic wave resonators being provided on the first substrate and a remaining second acoustic wave resonator being provided on the second substrate, and a resonator closest to the receive terminal in a plan view among the one or some first and second acoustic wave resonators being a second acoustic wave resonator of the one or some second acoustic wave resonators.

A multiplexer includes: first and second substrates overlapping with each other with an air gap interposed therebetween; a first filter disposed on the first substrate and including first series resonators connected in series with a first path, and first parallel resonators; and a second filter disposed on the second substrate and including second series resonators connected in series with a second path, and second parallel resonators connected between the second path and a ground, each of the second series resonators and the second parallel resonators including a piezoelectric film, a first electrode interposed between the piezoelectric film and the second substrate, a second electrode interposed between the piezoelectric film and the air gap, and a resonance region, in at least one second parallel resonator, the first electrode being coupled to the second path, the second electrode being coupled to the ground, the resonance region overlapping with the first path.

An acoustic wave component is disclosed. The acoustic wave component can include a bulk acoustic wave resonator and a surface acoustic wave device. The bulk acoustic wave resonator can include a first portion of a ceramic substrate, a first piezoelectric layer positioned on the ceramic substrate, and electrodes positioned on opposing sides of the first piezoelectric layer. The surface acoustic wave device can include a second portion of the ceramic substrate, a second piezoelectric layer positioned on the ceramic substrate, and an interdigital transducer electrode on the second piezoelectric layer.

A bulk acoustic wave resonator is disclosed. The bulk acoustic wave resonator can include a ceramic substrate, and a piezoelectric layer on the ceramic substrate. The bulk acoustic wave resonator can also include first and second electrodes positioned on opposing sides of the piezoelectric layer. The bulk acoustic wave resonator can also include passivation layers that includes a first passivation layer and a second passivation layer. The first passivation layer can be positioned between the ceramic substrate and the first electrode. The second electrode can be positioned between the piezoelectric layer and the second passivation layer. The bulk acoustic wave resonator can further include a frame structure along an edge of an active region of the bulk acoustic wave resonator.

A radio frequency (RF) front-end (RFFE) device includes a die having a front-side dielectric layer on an active device. The active device is on a first substrate. The RFFE device also includes a microelectromechanical system (MEMS) device. The MEMS device is integrated on the die at a different layer than the active device. The MEMS device includes a cap layer composed of a cavity in the front-side dielectric layer of the die. The cavity in the front-side dielectric layer is between the first substrate and a second substrate. The cap is coupled to the front-side dielectric layer.

A multiplexer includes: a first terminal; a second terminal; a third terminal; a first filter connected between the first and second terminals, including a first capacitor, a first inductor, and one or more first acoustic wave resonators, and having a first passband; a second filter connected between the first and third terminals, including a second capacitor, a second inductor, and one or more second acoustic wave resonators, and having a second passband higher than the first passband; a substrate having a surface on which at least one first acoustic wave resonator of the one or more first acoustic wave resonators and at least one second acoustic wave resonator of the one or more second acoustic wave resonators are located; and a metal structure located on the surface and located between the at least one first acoustic wave resonator and the at least one second acoustic wave resonator.

A substrate that includes an encapsulation layer, a first acoustic resonator, a second acoustic resonator, at least one first dielectric layer, a plurality of first interconnects, at least one second dielectric layer, and a plurality of second interconnects. The first acoustic resonator is located in the encapsulation layer. The first acoustic resonator includes a first piezoelectric substrate comprising a first thickness. The second acoustic is located in the encapsulation layer. The second acoustic resonator includes a second piezoelectric substrate comprising a second thickness that is different than the first thickness. The at least one first dielectric layer is coupled to a first surface of the encapsulation layer. The plurality of first interconnects is coupled to the first surface of the encapsulation layer. The plurality of first interconnects is located at least in the at least one first dielectric layer.

A piezoelectric thin film resonator includes: a substrate; a piezoelectric film located on the substrate and including a penetration hole penetrating therethrough; a lower electrode and an upper electrode facing each other across at least a part of the piezoelectric film; and a protective film covering an upper surface of the piezoelectric film, a side surface of the piezoelectric film, and an inner surface of the penetration hole.

An electronic component includes a first substrate having a substantially quadrangular planar shape and having a first surface and a second surface, the first surface and the second surface being opposite to each other, an element disposed on the first surface, four first terminals located adjacent to four corners on the second surface, respectively, and a second terminal located between the first terminals at respective ends of each of two sides opposite to each other of the second surface, an area of the second terminal being smaller than an area of each of the first terminals at the respective ends of each of the two sides, a width of the second terminal in an extension direction of each of the two sides being equal to or less than a width of each of the first terminals at the respective ends of each of the two sides in the extension direction.

The acoustic wave filter (10A) includes a parallel-arm resonant circuit (12p). The parallel-arm resonant circuit (12p) includes a parallel-arm resonator (p1) and a frequency variable circuit (72p) that are connected in parallel. The frequency variable circuit (72p) includes a parallel-arm resonator (p2) that has a resonant frequency higher than that of the parallel-arm resonator (p1) and a switch (SW1) element. A frequency difference between a resonant frequency on a higher frequency side of the parallel-arm resonant circuit (12p) in a case where the switch (SW1) is OFF and a resonant frequency on a higher frequency side of the parallel-arm resonant circuit (12p) in a case where the switch (SW1) is ON is equal to or more than a frequency difference between a low frequency end frequency of the second attenuation band and a low frequency end frequency of the first attenuation band.