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 substrate for a surface acoustic wave device or bulk acoustic wave device, comprising a support substrate and an piezoelectric layer on the support substrate, wherein the support substrate comprises a semiconductor layer on a stiffening substrate having a coefficient of thermal expansion that is closer to the coefficient of thermal expansion of the material of the piezoelectric layer than that of silicon, the semiconductor layer being arranged between the piezoelectric layer and the stiffening substrate.

An acoustic resonator includes: a resonating unit including a resonating unit including a piezoelectric layer and first and second electrodes disposed on a lower side and an upper side of the piezoelectric layer, respectively; a substrate disposed on a lower side of the resonating unit; a support unit providing a cavity between the substrate and the resonating unit; and an intermediate metal layer separated from the second electrode and disposed in the resonating unit such that at least a portion thereof is surrounded by the piezoelectric layer and the second electrode.

A resonator device includes a quartz crystal substrate, a resonator element including a first excitation electrode arranged on a first surface of the quartz crystal substrate, a second excitation electrode arranged on a second surface of the quartz crystal substrate in opposition to the first excitation electrode, and first and second pad electrodes that are arranged on the first surface and are coupled to the first and second excitation electrodes, a base including a substrate and first and second interconnects arranged on the substrate, a first bonding member bonding the first pad electrode to the first interconnect, and a second bonding member bonding the second pad electrode to the second interconnect. The first and second bonding members are arranged such that a first imaginary line that passes through a centroid of the resonator element and is parallel to an X axis is interposed between the first and second bonding members. An angle θ1 formed between the first imaginary line and a second imaginary line passing through the first bonding member and the second bonding member is 100°<θ1<140°.

An acoustic wave device can have a plurality of coupling portions configured to electrically couple electrodes of the device to the substrate of the device to provide a bypass current pathway through the substrate for heat management. The substrate can be a semiconductor material, which can become more conductive as the temperature increases so that the bypass current pathway diverts more power through the substrate as the temperature increases. The acoustic wave device can be a surface acoustic wave device, which can have an interdigital transducer electrode that has the coupling portions on each of the bus bars and extending through the piezoelectric layer to contact the substrate. The acoustic wave device can be a bulk acoustic wave device in some implementations.

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.

A BAW resonance device, a filter device and an RF front-end device are provided. The BAW resonance device comprises a first passive part including a first substrate and a first heat-dissipation layer located over the first substrate; a first active part including a first piezoelectric layer, a first electrode layer and a second electrode layer, wherein the first piezoelectric layer is located over the first passive part and has a first side and a second side opposite to the first side, the first passive part is located on the first side, the first electrode layer is also located on the first side and is disposed between the first passive part and the first piezoelectric layer, and the second electrode layer is located on the second side; and a first cavity located on the first side and disposed between the first passive part and the first piezoelectric layer, wherein at least one part of the first electrode layer is located on or in the first cavity. The first heat-dissipation layer can improve or flexibly adjust the heat-dissipation performance of the SAW resonance device.

An oven-controlled crystal oscillator according to one or more embodiments includes a core section having at least an oscillation IC, a crystal resonator, and a heater IC. The core section is hermetically encapsulated in a heat-insulating package. The core section is supported by the package via a core substrate. The core substrate is connected to the package outside a region where the core section is provided in plan view.

A circuit device includes a first terminal, a first oscillation circuit oscillating a resonator and generating a first voltage for automatic gain control for controlling amplitude of a signal output from the resonator, a digital signal generation circuit generating a digital signal corresponding to the first voltage, and a first interface circuit outputting the digital signal to the first terminal.