A piezoelectric transducer for measuring a force includes a base element; a pre-loading element; at least one effective main seismic mass aggregation of pre-loaded parts capable of producing the force when being accelerated; a main piezoelectric ceramic element including a first piezoelectric ceramic; at least one compensation seismic mass aggregation of pre-loaded parts capable of producing a compensation force when being accelerated; a compensation piezoelectric ceramic element including a second piezoelectric ceramic. The first piezoelectric ceramic has a thermal sensitivity shift smaller than the second piezoelectric ceramic. The main piezoelectric ceramic element is oriented with respect to the force to be measured and the compensation piezoelectric ceramic element is oriented with respect to the compensation force such that the main electric charge and the compensation electric charge are opposite in polarity.

A method for manufacturing a piezoelectric device that includes a substrate, a piezoelectric layer directly or indirectly supported by the substrate and arranged above the substrate, a heater, and a heater electrode for driving the heater. Moreover, the method includes forming the piezoelectric layer, the heater, and the heater electrode and subjecting the piezoelectric device to heat treatment with heat generated from the heater by driving the heater by feeding electric power to the heater electrode.

A method for fabricating bulk acoustic wave resonator with mass adjustment structure, comprising following steps of: forming a sacrificial structure mesa on a substrate; etching the sacrificial structure mesa such that any two adjacent parts have different heights, a top surface of a highest part of the sacrificial structure mesa is coincident with a mesa top extending plane; forming an insulating layer on the sacrificial structure mesa and the substrate; polishing the insulating layer to form a polished surface; forming a bulk acoustic wave resonance structure including a top electrode, a piezoelectric layer and a bottom electrode on the polished surface; etching the sacrificial structure mesa to form a cavity; the insulating layer between the polished surface and the mesa top extending plane forms a frequency tuning structure, the insulating layer between the mesa top extending plane and the cavity forms a mass adjustment structure.

An electronic package includes a first substrate and a second substrate disposed beneath the first substrate. The electronic package also includes a perimeter wall extending between an inner surface of the first substrate and an opposing inner surface of the second substrate to provide separation between the first substrate and the second substrate. A cavity exists between opposing inner surfaces of the first substrate and the second substrate. A first filter comprising a first plurality of bulk acoustic wave (BAW) resonators disposed over the inner surface first substrate. The electronic package also includes a second filter comprising a second plurality of BAW resonators disposed over the second substrate

A method for forming cavity of bulk acoustic wave resonator comprising following steps of: forming a sacrificial epitaxial structure mesa on a compound semiconductor substrate; forming an insulating layer on the sacrificial epitaxial structure mesa and the compound semiconductor substrate; polishing the insulating layer by a chemical-mechanical planarization process to form a polished surface; forming a bulk acoustic wave resonance structure on the polished surface, which comprises following steps of: forming a bottom electrode layer on the polished surface; forming a piezoelectric layer on the bottom electrode layer; and forming a top electrode layer on the piezoelectric layer, wherein the bulk acoustic wave resonance structure is located above the sacrificial epitaxial structure mesa; and etching the sacrificial epitaxial structure mesa to form a cavity, wherein the cavity is located under the bulk acoustic wave resonance structure.

A filter includes a multilayer structure having films configured as bulk acoustic wave resonators; a wiring line connected to the bulk acoustic wave resonators; a cap coupled to the multilayer structure on a bonding line; and the filtering characteristics of the filter being configured through a mutual inductance between the wiring line and the bonding line.

A filter may include a plurality of bulk acoustic wave resonators including one or more series resonators and one or more shunt resonators formed by a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate, a cap accommodating the plurality of bulk acoustic wave resonators therein, and one or more switches provided on the cap.

A bulk acoustic wave (BAW) resonator includes: a substrate; a first BAW resonator including a first air cavity disposed in the substrate, and further including a first electrode, a first piezoelectric layer, and a second electrode stacked on the first air cavity; a second BAW resonator including a second air cavity disposed in the substrate, and further including a first electrode, a second piezoelectric layer, and a second electrode stacked on the second air cavity, wherein the second BAW resonator is connected in parallel to the first BAW resonator and has polarities that are opposite of polarities of the first BAW resonator; and a compensation capacitor circuit connected between the first BAW resonator and the second BAW resonator.

Provided are a band-pass filter circuit and a multiplexer. The band-pass filter circuit includes an electromagnetic LC filter circuit and acoustic resonance units. At least one of the acoustic resonance units each includes at least one first acoustic resonator and at least one second acoustic resonator. The first acoustic resonator is connected in series between the band-pass filter circuit and the electromagnetic LC filter circuit. Each of the at least one second acoustic resonator is connected to a terminal of the at least one first acoustic resonator, where the first terminal of the band-pass filter circuit serves as an input terminal or output terminal of the band-pass filter circuit. One or more of the acoustic resonance units are connected on an input side of the electromagnetic LC filter circuit; and the remaining of the acoustic resonance units are connected on an output side of the electromagnetic LC filter circuit.

An acoustic resonator includes a substrate, and a resonant portion comprising a center portion in which a first electrode, a piezoelectric layer and a second electrode are sequentially laminated on the substrate, and an extending portion disposed along a periphery of the center portion, wherein the resonant portion is configured to have an asymmetrical polygonal plane, an insertion layer is disposed below the piezoelectric layer in the extending portion, and the piezoelectric layer is configured to have a top surface which is raised to conform to a shape of the insertion layer, and the insertion layer is configured to have an asymmetrical polygonal shape corresponding to a shape of the extending portion.