Disclosed herein are embodiments of a ladder-type filter comprising a plurality of series arm resonators and a plurality of parallel arm resonators, at least one of the plurality of series arm resonators including a piezoelectric substrate and an interdigital transducer electrode disposed on the piezoelectric substrate, an aperture W1 of the interdigital transducer electrode being configured to be less than 13λ, where λ is a wavelength of a surface acoustic wave excited by the interdigital transducer electrode. The relationship between the aperture W1 and the wavelength λ can be W1 < 13λ, W1 < 11λ, W1 < 4λ, or W1 > 6λ.

Filter devices and fabrication methods are disclosed. A filter device includes a piezoelectric plate and a conductor pattern on a front surface of the piezoelectric plate. The conductor pattern includes interdigital transducers (IDTs) of a plurality of transversely-excited film bulk acoustic resonators (XBARs) and a plurality of conductors connecting the plurality of XBARs in a ladder filter circuit architecture. The plurality of conductors includes a first conductor adjacent to a second conductor. An opening is provided through the piezoelectric plate between the first conductor and the second conductor.

Disclosed are a resonator and a manufacturing method thereof, a filter, and an electronic device. The resonator includes a substrate, a Bragg reflection layer, and a piezoelectric layer that are sequentially stacked. A first electrode is disposed on a surface that is of the piezoelectric layer and that faces the Bragg reflection layer, a second electrode is disposed on a surface that is of the piezoelectric layer and that is away from the Bragg reflection layer, a border ring is disposed on a surface that is of the second electrode and that is away from the piezoelectric layer, and the resonator has a first resonance region and a second resonance region corresponding to the border ring.

A resonator and a preparation method of a resonator, and a filter relate to the technical field of resonators. The preparation method includes: forming a piezoelectric layer, a first electrode layer, and a first bonding layer on a first substrate; patterning the first bonding layer to form a first bonding ring, a second bonding ring, and a third bonding ring, and etching an exposed part of the first electrode layer to form a first window; forming a first supporting layer and a second bonding layer on the second substrate; patterning the second bonding layer to form a fourth bonding ring and a fifth bonding ring, and etching an exposed part of the first supporting layer to form a second window and a third window to obtain a boundary ring located between the third window and the second window; bonding the third bonding ring and the fifth bonding ring, and bonding the second bonding ring and the fourth bonding ring to obtain a cavity structure of the resonator; and removing the first substrate, and forming a second electrode layer on the piezoelectric layer. According to the preparation method, preparation of the boundary ring is realized through a packaging and bonding process, and the preparation process of a resonator is simple.

An acoustic structure is provided. The acoustic structure includes an acoustic resonator structure configured to resonate in a series resonance frequency (e.g., passband frequency) to pass a signal, or cause a series capacitance to block the signal in a parallel resonance frequency (e.g., stopband frequency). The parallel resonance frequency may become higher than the series resonance frequency when the tunable capacitance is lesser than or equal to two times of the series capacitance (C.sub.Tune≤2C.sub.0), or lower than the series resonance frequency when the tunable capacitance is greater than two times of the series capacitance (C.sub.Tune>2C.sub.0). In this regard, the acoustic structure can be configured to include a tunable reactive circuit to generate the tunable capacitance (C.sub.Tune) to adjust the parallel resonance frequency. As such, it may be possible to flexibly configure the acoustic resonator structure to block the signal in desired stopband frequencies.

An acoustic structure is provided. The acoustic structure includes an acoustic resonator structure configured to resonate in a series resonance frequency (e.g., passband frequency) to pass a signal, or cause a series capacitance to block the signal in a parallel resonance frequency (e.g., stopband frequency). The parallel resonance frequency may become higher than the series resonance frequency when the tunable capacitance is lesser than or equal to two times of the series capacitance (C.sub.Tune≤2C.sub.0), or lower than the series resonance frequency when the tunable capacitance is greater than two times of the series capacitance (C.sub.Tune>2C.sub.0). In this regard, the acoustic structure can be configured to include a tunable reactive circuit to generate the tunable capacitance (C.sub.Tune) to adjust the parallel resonance frequency. As such, it may be possible to flexibly configure the acoustic resonator structure to block the signal in desired stopband frequencies.

Techniques for improving structures, acoustic wave resonators, layers, and devices are disclosed, including filters, oscillators and systems that may include such devices. An acoustic wave device of this disclosure may comprise a substrate and a piezoelectric resonant volume. The piezoelectric resonant volume of the acoustic wave device may have a main resonant frequency. The acoustic wave device may comprise a first distributed Bragg acoustic reflector. The first distributed Bragg acoustic reflector may comprise a first active piezoelectric layer. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in a super high frequency (SHF) band. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in an extremely high frequency (EHF) band.

An acoustic wave device includes a piezoelectric layer that is made of lithium niobate or lithium tantalate, and a plurality of pairs of electrodes opposed to each other in a direction intersecting with a thickness direction of the piezoelectric layer, in which a bulk wave in a thickness shear primary mode is used or d/p is about 0.5 or lower when a thickness of the piezoelectric layer is d and a distance between centers of mutually adjacent electrodes among the plurality of pairs of electrodes is p. The plurality of pairs of electrodes include at least one pair of first electrodes of a first acoustic wave resonator and at least one pair of second electrodes of a second acoustic wave resonator. A direction orthogonal to a longitudinal direction of the second electrodes in the second acoustic wave resonator is inclined at an angle that is greater than 0° and smaller than 360° with respect to a direction orthogonal to a longitudinal direction of the first electrodes in the first acoustic wave resonator.

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 acoustic filter device includes first and second series resonators and at least one shunt resonator, each shunt resonator electrically coupled to the first series resonator or the second series resonator. Each of the first and second series resonators includes respective first and second sub-resonators electrically connected in series, The first sub-resonators of the first and second series resonators are acoustically coupled along a first shared acoustic track. The second sub-resonators of the first and second series resonators are acoustically coupled along a second shared acoustic track.