A filter module includes an inductor, a filter including first wiring, and second wiring between the inductor and the first wiring and being a direct-current floating potential. The inductor and the first wiring are magnetically coupled, the inductor and the second wiring are magnetically coupled, and the first wiring and the second wiring are capacitively coupled.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

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.

A filter circuit comprises in a signal line a band filter (BF) allowing to let pass a useful frequency band and a notch filter (NF) circuited in series to the band filter for filtering out a stop band frequency. The notch filter comprises a series circuit of a number of parallel shunt elements (SE1 . . . SE6) wherein each shunt element is shifted infrequency against the other shunt elements that the frequencies thereof are distributed (f1 . . . F6) over a notch band. All shunt elements may be realized as a SAW one-port resonator (TR.sub.NF) including regions with different pitches.

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.

Disclosed is a semiconductor device including a semiconductor die, a base member, a side wall, first and second conductive films, and first and second conductive leads. The base member has a conductive main surface including a region that mounts the semiconductor die. The side wall surrounds the region and is made of a dielectric. The side wall includes first and second portions. The first and second conductive films are provided on the first and second portions, respectively and are electrically connected to the semiconductor die. The first and second conductive leads are conductively bonded to the first and second conductive films, respectively. At least one of the first and second portions includes a recess on its back surface facing the base member, and the recess defines a gap between the at least one of the first and second portions below the corresponding conductive film and the base member.

Aspects of this disclosure relate to a multiplexer with an acoustic assisted trap circuit. The multiplexer includes an acoustic wave filter with an acoustic wave resonator and an impedance network that together provide a trap for a harmonic associated with another acoustic wave filter of the multiplexer. The acoustic wave filter can have an edge of a passband that is farther from the harmonic than other acoustic filters of the multiplexer.

A multiplexer includes a first transmission filter connected to a common terminal, a reception filter, a second transmission filter, and a multilayer substrate. The first transmission filter includes a first parallel-arm resonator connected to a first parallel-arm terminal and a second parallel-arm resonator connected to a second parallel-arm terminal. The second transmission filter includes a third parallel-arm resonator connected to a third parallel-arm terminal and a fourth parallel-arm resonator connected to a fourth parallel-arm terminal. The first to fourth parallel-arm resonators are surface-mounted on a main surface of the multilayer substrate. The second and third parallel-arm terminals are grounded on any dielectric layer from the main surface to an n-th dielectric layer of the multilayer substrate and the first and fourth parallel-arm terminals are isolated from each other on the dielectric layers from the main surface to the n-th dielectric layer.

An acoustic wave device includes a substrate, a multilayer film on the substrate, an LT layer configured by a single crystal of LiTaO.sub.3 on the multilayer film, and an IDT electrode on the LT layer. The thickness of the LT layer is 0.3λ or less where λ is two times a pitch p of electrode fingers in the IDT electrode. Euler angles of the LT layer are (0°±20°, −5° to 65°, 0°±10°), (−120°±20°, −5° to 65°, 0°±10°), or (120°±20°, −5° to 65°, 0°±10°). The multilayer film configured by alternately stacking at least one first layer and at least one second layer. The first layer is comprised of SiO.sub.2. The second layer is comprised of any one of Ta.sub.2O.sub.5, HfO.sub.2, ZrO.sub.2, TiO.sub.2, and MgO.

An acoustic wave device including: a POI structure including: a material layer where a high acoustic velocity layer and a low acoustic velocity layer are alternate, a substrate is a lowermost high acoustic velocity layer; a first piezoelectric layer located above the material layer, wherein a layer adjacent to the first piezoelectric layer is referred to as a surface low acoustic velocity layer; wherein an acoustic velocity of a bulk wave propagated in the high acoustic velocity layer and the low high acoustic velocity layer is higher than and lower than an acoustic velocity of a bulk wave of the first piezoelectric layer, respectively. The POI structure includes at least two regions, a first device having a resonance of a first vibration mode is manufactured in the first region, and a second device having a resonance of a second vibration mode is manufactured in a second region.