A filter includes a piezoelectric film including lithium niobate or lithium tantalate, an acoustic wave resonator including a functional electrode on the piezoelectric film, a capacitor on the piezoelectric film and connected in parallel to the acoustic wave resonator, and a resonator electrically connected to the acoustic wave resonator. The functional electrode includes a pair of first and second electrodes facing each other in a direction intersecting a thickness direction of the piezoelectric film. When a thickness of the piezoelectric film is d and a center-to-center distance between the first electrode and the second electrode is p, d/p is smaller than or equal to about 0.5.

Techniques for improving acoustic resonators and resonator structures are disclosed, including filters, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate. The bulk acoustic wave (BAW) may further comprise a plurality of piezoelectric layers including first, second, third and fourth piezoelectric layers acoustically coupled with one another and arranged over the substrate. The first, second, third and fourth piezoelectric layers may have respective piezoelectric axis orientations. The first, second, third and fourth piezoelectric layers may have respective thicknesses. Electromechanical coupling of the bulk acoustic wave (BAW) resonator may, but need not be limited.

Aspects of this disclosure relate to methods of manufacturing bulk acoustic wave components. Such methods include plasma dicing to singulate individual bulk acoustic wave components. A buffer layer can be formed over a substrate of bulk acoustic wave components such that streets are exposed. The bulk acoustic wave components can be plasma diced along the exposed streets to thereby singulate the bulk acoustic wave components

A filter device has a substrate with a first cavity and a second cavity on a single die; and a bonding layer formed on the substrate but not spanning the first cavity or the second cavity. A piezoelectric plate is bonded to the bonding layer and spans the first and the second cavity. However, excess portions of piezoelectric plate are removed that extend a certain length past the perimeter of the first cavity and of the second cavity. Excess portions may be piezoelectric material that extends in the length and width direction past the perimeter of a cavity by more than between 2 and 25 percent of the cavity perimeter. An interdigital transducer (IDT) is on a front surface of the piezoelectric plate and having interleaved fingers over the first cavity.

Resonator devices, filter devices, and methods of fabrication are disclosed. A resonator device includes a substrate and a single-crystal piezoelectric plate having front and back surfaces. An acoustic Bragg reflector is sandwiched between a surface of the substrate and the back surface of the piezoelectric plate. An interdigital transducer (IDT) is formed on the front surface of the piezoelectric plate. The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a primary acoustic mode within the piezoelectric plate. The acoustic Bragg reflector comprises alternating SiO.sub.2 and diamond layers and is configured to reflect the primary acoustic mode.

A multi-stage matching network filter circuit device. The device comprises bulk acoustic wave (BAW) resonator device having an input node, an output node, and a ground node. A first matching network circuit is coupled to the input node. A second matching network circuit is coupled to the output node. A ground connection network circuit coupled to the ground node. The first or second matching network circuit can include an inductive ladder network including a plurality of series inductors in a series configuration and a plurality of grounded inductors wherein each of the plurality of grounded inductors is coupled to the connection between each connected pair of series inductors. The inductive ladder network can include one or more LC tanks, wherein each of the one or more LC tanks is coupled between a connection between a series inductor and a subsequent series inductor, which is also coupled to a grounded inductor.

Radio frequency filters are disclosed. A filter includes a first transversely-excited film bulk acoustic resonator (XBAR) having a first sub-resonator and a second sub-resonator connected in parallel. A pitch of the first sub-resonator is not equal to a pitch of the second sub-resonator and/or a mark of the first sub-resonator is not equal to a mark of the second sub-resonator.

Acoustic resonators, acoustic filter devices and methods of making the same. An acoustic resonator device includes a piezoelectric layer having front and back surfaces, a high acoustic velocity layer on the back surface, and an interdigital transducer (IDT) on the front surface. The high acoustic velocity layer has a higher acoustic velocity than an acoustic velocity of the piezoelectric layer.

Resonator and filter devices and methods of fabrication. A resonator chip includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between the substrate and a back surface of the piezoelectric plate. A conductor pattern on a front surface of the piezoelectric plate includes a first plurality of contact pads and an interdigital transducer (IDT). The IDT and the piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic mode within the piezoelectric plate. The acoustic Bragg reflector is configured to reflect the shear primary acoustic mode. An interposer has a second plurality of contact pads on a back surface. A seal connects a perimeter of the piezoelectric plate to a perimeter of the interposer. Each contact pad of the first plurality of contact pads is directly connected to a respective contact pad of the second plurality of contact pads.

Aspects of the disclosure relate BAW resonator with improved performance, RF-filter. A BAW resonator with improved performance is provided. The resonator includes a piezoelectric material sandwiched between a first electrode and a second electrode. The piezoelectric material is provided as a monocrystalline material having a particular orientation defined by a particular Euler angle such as the piezoelectric material being LiTaO.sub.3 and having an orientation with Euler angles selected from [0°±5°; 130°±15°; n°±5°], or a symmetrical equivalent.