A transducer structure for a surface acoustic device comprises a composite substrate comprising a piezoelectric layer, a pair of inter-digitated comb electrodes, comprising a plurality of electrode means with a pitch p satisfying the Bragg condition, wherein the inter-digitated comb electrodes are embedded in the piezoelectric layer such that, in use, the excitation of a wave propagating mode in the volume of the electrode means is taking place and is the predominant propagating mode of the structure. The present disclosure relates also to an acoustic wave device comprising at least one transducer structure as described above and to a method for fabricating the transducer structure. The present disclosure relates also to the use of the frequency of the bulk wave propagating in the electrode means of the transducer structure in an acoustic wave device to generate contribution at high frequency, in particular, above 3 GHz.

An acoustic wave device includes a support substrate including a cavity portion and a support portion, a piezoelectric film on the support portion and including a first and second main surfaces, a functional electrode on the first main surface, and a heat dissipation film on at least one of the first and second main surfaces and includes a semiconductor or an insulator. The functional electrode includes at least one pair of first and second electrodes. When a thickness of the piezoelectric film is dx and a middle-to-middle distance between the first and second electrodes is p, dx/p is about 0.5 or less. The heat dissipation film overlaps at least a portion of the support portion in plan view. A thermal conductivity of the heat dissipation film is higher than a thermal conductivity of the piezoelectric film, and a thickness of the heat dissipation film is less than the thickness of the piezoelectric film.

A bulk acoustic wave resonator is provided. The bulk acoustic wave resonator includes a board; a resonant portion including a first electrode, a piezoelectric layer, and a second electrode, and disposed on the board, and a temperature compensation layer disposed on the resonant portion, wherein the temperature compensation layer includes a temperature compensation portion formed of a dielectric and a loss compensation portion formed of a material different from a material of the temperature compensation portion, and wherein each of the temperature compensation portion and the loss compensation portion includes a plurality of linear patterns, and the linear patterns of the temperature compensation portion and the linear patterns of the loss compensation portion are alternately disposed.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a support substrate, a solid acoustic mirror on the support substrate, a piezoelectric layer on the solid acoustic mirror, and an interdigital transducer electrode on the piezoelectric layer. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave.

A high frequency module includes a mounting substrate, an acoustic wave filter, a protection member, a resin layer, and a shield layer. The acoustic wave filter is mounted on a first main surface of the mounting substrate. The protection member is disposed on a main surface of the acoustic wave filter that is far from the mounting substrate. The resin layer is disposed on the first main surface of the mounting substrate and covers an outer peripheral surface of the acoustic wave filter and an outer peripheral surface of the protection member. The shield layer covers the resin layer and the protection member. The protection member is in contact with both the acoustic wave filter and the shield layer. The acoustic wave filter includes a piezoelectric substrate. A main surface of the piezoelectric substrate that is far from the mounting substrate is in contact with the protection member.

Heat dissipating characteristics of an acoustic wave filter is improved. A high frequency module includes a mounting substrate, an acoustic wave filter, a resin layer, and a shield layer. The mounting substrate has a first main surface and a second main surface that face each other. The acoustic wave filter is arranged near the first main surface of the mounting substrate. The resin layer is arranged on the first main surface of the mounting substrate and covers an outer peripheral surface of the acoustic wave filter. The shield layer covers the resin layer and the acoustic wave filter. The shield layer is in contact with a second main surface of the acoustic wave filter that is far from the mounting substrate.

An acoustic wave device is disclosed. The acoustic wave deice can include a membrane structure and a support substrate. The membrane structure includes a piezoelectric layer, an interdigital transducer electrode arranged on the piezoelectric layer, and a thermally conductive layer arranged at least partially in contact with the piezoelectric layer. The support substrate is connected to the membrane structure and configured such that a cavity is provided next to the membrane structure. The acoustic wave device can laterally excite a bulk acoustic wave.

Acoustic resonator devices are disclosed. An acoustic resonator device includes a plurality of cells electrically connected in parallel. Each cell includes an interdigital transducer (IDT) on a piezoelectric plate, the IDT having at least 15 and not more than 35 interleaved fingers.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a first solid acoustic mirror, a second solid acoustic mirror, a piezoelectric layer that is positioned between the first solid acoustic mirror and the second solid acoustic mirror, an interdigital transducer electrode on the piezoelectric layer, and a support substrate arranged to dissipate heat associated with the bulk acoustic wave. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the bulk acoustic wave. The first solid acoustic mirror is positioned on the support substrate.

A device including at least one sensing bulk acoustic wave (BAW) resonator including a sensing surface; a fluid channel, wherein the sensing surface of the at least one sensing BAW resonator is disposed adjacent to or within the fluid channel; at least one resistive heater; and at least one temperature detector, wherein the at least one temperature detector is configured to monitor the temperature adjacent to the at least one BAW resonator and affect a current to be passed through the at least one resistive heater.