Abstract: Filter devices. A first chip includes a first base, a first piezoelectric membrane having a first thickness, and a first acoustic Bragg reflector sandwiched between the first piezoelectric membrane and the first base. A first interdigital transducer (IDT) of a first solidly-mounted membrane resonator is formed on a surface of the first piezoelectric membrane. A second chip includes a second base, a second piezoelectric membrane having a second thickness less than the first thickness, and a second acoustic Bragg reflector sandwiched between the second piezoelectric membrane and the second base. A second IDT of a second solidly-mounted membrane resonator is formed on a surface of the second piezoelectric membrane. A circuit card is coupled to the first chip and the second chip, the circuit card including at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Filter devices are disclosed. A filter device a first chip having a substrate; a piezoelectric layer attached either directly or via one or more intermediate layers the substrate; and one or more electrodes of a respective plurality of resonators of the first chip including a shunt resonator of the first chip; a first dielectric layer having a first thickness at least partially on the one or more electrodes of the shunt resonator; a second chip having a substrate a piezoelectric layer attached either directly or via one or more intermediate layers to the substrate; and one or more electrodes of a respective plurality of resonators of the second chip including a series resonator of the second chip; a second dielectric layer having a second thickness different than the first thickness at least partially on the one or more electrodes of the series resonator of the second chip.

Abstract: A filter device is provided that includes a first chip comprising at least one first bulk acoustic resonator including a first piezoelectric material between a first upper conductor and a first lower conductor; a second chip comprising at least one second bulk acoustic resonator including a second piezoelectric material between a second upper conductor and a second lower conductor; and a circuit card coupled to the first chip and the second chip. A thickness of the first piezoelectric material is greater than a thickness of the second piezoelectric material.

Abstract: A filter device is provided that includes a first chip comprising a first IDT of a first solidly-mounted resonator on a surface of a first piezoelectric layer. The IDT including a first plurality of interleaved fingers having a first thickness. A first acoustic reflector is sandwiched between the first piezoelectric layer and a first base. The filter device includes a second chip having a second IDT of a second solidly-mounted resonator on a surface of a second piezoelectric layer. The second IDT includes a second plurality of interleaved fingers having a second thickness that is different from the first thickness. A second acoustic reflector is sandwiched between the second piezoelectric layer and a second base. An electrical connection is provided between the first IDT and the second IDT.

Abstract: A filter device is provided that includes a acoustic resonator having a substrate; a piezoelectric layer coupled to the substrate by one or more intermediate layers; and a conductor pattern on a surface of the piezoelectric layer, the conductor pattern including a pair of busbars having a plurality of interleaved fingers extending therefrom to form an interdigital transducer (IDT). The filter device further includes a dielectric capacitor electrically coupled in series to the acoustic resonator. The dielectric capacitor includes a dielectric layer on a surface of a first busbar of the pair of busbars and at least one metal layer on a surface of the dielectric layer, such that the dielectric layer is between the first busbar and the at least one metal layer to form the dielectric capacitor.

Abstract: An acoustic resonator is provided that includes a piezoelectric layer; an interdigital transducer on the piezoelectric layer and that includes a plurality of interleaved fingers; a lid disposed above the piezoelectric layer and defining a first cavity between the lid and the piezoelectric layer; a substrate disposed below the piezoelectric layer opposite the lid; and a second cavity between at least a portion of the piezoelectric layer and at least a portion of the substrate. Moreover, a height of the first cavity is greater than a pitch of at least two interleaved fingers of the plurality of interleaved fingers and at most four times greater than a height of the second cavity.

Abstract: A bulk acoustic resonator that includes a substrate, a piezoelectric plate, and an interdigital transducer (IDT) formed on the front surface of the piezoelectric plate. The IDT is configured to excite a primary shear acoustic mode within the piezoelectric plate. Also included is a half-lambda dielectric layer on at least one of the front surface or the back surface of the piezoelectric plate, where a thickness of the half-lambda dielectric layer is related to a wavelength of a fundamental shear bulk acoustic wave resonance in the half-lambda dielectric layer. The device further includes an acoustic Bragg reflector sandwiched between the surface of the substrate and the back surface of the piezoelectric plate, the acoustic Bragg reflector configured to reflect the primary acoustic mode. A top layer of the alternating layers of the acoustic Bragg reflector contacts the piezoelectric plate or the half-lambda dielectric layer.

Abstract: An apparatus for filtering radio frequency signals is provided. The apparatus includes a substrate and a membrane coupled to the substrate that includes piezoelectric material. The apparatus also includes an interdigital transducer (IDT) coupled to the membrane and includes a plurality of interleaved fingers. The apparatus also includes a lid, in which the membrane is arranged between the substrate and the lid with a first cavity having a first height between the lid and a first main surface of the membrane and a second cavity having a second height between the substrate and a second main surface of the membrane that opposes the first main surface. Moreover, the first height between the lid and the first main surface of the membrane is greater than a pitch of at least one pair of interleaved fingers of the plurality of interleaved fingers and at most four times greater than the second height.

Abstract: A filter device is provided that includes a substrate having a surface and a piezoelectric plate supported by the substrate. A plurality of interdigital transducers (IDTs) for multiple resonators are provided that each have interleaved fingers at respective diaphragms of the piezoelectric plate disposed over one or more cavities. Moreover, a first resonator includes a first plurality of interleaved fingers having a first pitch and a second resonator includes a second plurality of interleaved fingers having a second pitch that is different than the first pitch. This configuration adjusts the resonance frequencies of each resonator. Moreover, a dielectric layer may be uniformly disposed over at least one surface of the respective diaphragms of the piezoelectric plate.

Abstract: A filter device is provided a substrate; a piezoelectric layer attached to the substrate; a conductor pattern on a first surface of the piezoelectric layer and including a plurality of interdigital transducers of a plurality of resonators that each have interleaved fingers at s respective diaphragm; a first dielectric layer over at least the interleaved fingers of the plurality of interdigital transducers and on the first surface of the piezoelectric layer; and a second dielectric layer on the second surface of the piezoelectric layer that is opposite the first surface. The second dielectric layer provides a more uniform dielectric coating on the second surface of the piezoelectric layer than a coating of the at least one first dielectric layer that is over the interleaved fingers.

Abstract: Filter devices are disclosed. A filter device includes a piezoelectric plate comprising a supported portion, a first diaphragm, and a second diaphragm. The supported portion is attached to a substrate and the first and second diaphragms spans respective cavities in the substrate. A first interdigital transducer (IDT) has interleaved fingers on the first diaphragm. A second interdigital transducer (IDT) has interleaved fingers on the second diaphragm. A first dielectric layer is between the interleaved fingers of the first IDT, and a second dielectric layer is between the interleaved fingers of the second IDT. A thickness of the first dielectric layer is greater than a thickness of the second dielectric layer. The piezoelectric plate and the first and second IDTs are configured such that radio frequency signals applied to first and second IDTs excite primary shear acoustic modes in the respective diaphragms.

Abstract: Acoustic resonators, acoustic filter devices and methods of making the same. An acoustic resonator device includes a piezoelectric plate having front and back surfaces, an interdigital transducer (IDT) on the front surface including interleaved fingers extending alternately from opposed first and second busbars, an overlapping distance of the interleaved fingers defining an aperture of the acoustic resonator device, and a dielectric layer formed over and between the interleaved fingers, wherein the dielectric layer extends from between an edge of the aperture and the first busbar to between the an opposite edge of the aperture and the second busbar.

Abstract: A filter device is provided that includes a substrate and a piezoelectric plate attached to the substrate. A conductor pattern is formed at a first surface of the piezoelectric plate and includes interdigital transducers of series and shunt resonators that each have interleaved fingers at respective diaphragms of the plate suspended. A first dielectric coating layer is formed over the interleaved fingers of the IDTs and on the first surface of the piezoelectric plate; and a second dielectric coating layer is formed on the second surface of the piezoelectric plate that is opposite the first surface. The second dielectric coating layer of the shunt resonator has a greater thickness than a thickness of the at least one second dielectric coating layer of the series resonator.

Abstract: A bulk acoustic resonator, a filter device including the bulk acoustic resonator, and a radio frequency module including the filter device are provided. The bulk acoustic resonator includes a piezoelectric layer; and an IDT over a surface of the piezoelectric layer. The IDT includes first and second pluralities of interleaved fingers. A pair of subsections of the second plurality of interleaved fingers are disposed on opposing sides of the first plurality of interleaved fingers in a lengthwise direction of the IDT. A first thickness of the first plurality of interleaved fingers is different from a second thickness of the second plurality of interleaved fingers. Moreover, a first pitch of the first plurality of interleaved fingers is different from a second pitch of the second plurality of interleaved fingers.

Abstract: An acoustic resonator is provided that includes nanowires that each include a piezoelectric layer having first and second surfaces; a first electrode on the first surface; and a second electrode on the second surface. The nanowires each extend from a first busbar predominantly in a first direction, such that a space is defined between a pair of nanowires of the plurality of nanowires in a second direction that is substantially perpendicular to the first direction, such that there is no piezoelectric material between the pair of nanowires in the second direction. The nanowires each comprise a height in a thickness direction that is substantially orthogonal to the first and second directions. The nanowires each comprises a ratio of a width in the second direction of at least one of the first electrode and the second electrode to the height of the nanowire that is less than 2.

Abstract: Acoustic filters devices and methods of making the same. A filter device includes a plurality of series resonators acoustically coupled along a first shared acoustic track and a plurality of shunt resonators acoustically coupled along a second shared acoustic track and electrically coupled to the plurality of series resonators.

Abstract: 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.

Abstract: Acoustic resonators, filters, and methods. An exemplary filter includes a piezoelectric layer plate supported by a substrate; and three or more diaphragms of the piezoelectric layer spanning a respective cavity. A conductor pattern on the layer has interdigital transducers (IDTs) of three or more acoustic resonators. Each IDT has two sets of interleaved fingers extending from two busbars, respectively. Overlapping portions of the fingers define an aperture of each acoustic resonator. One or more of the resonators can have two dielectric strips that overlap the IDT fingers in first and second margins of the aperture and that extend into first and second gaps between the first and second margins and the busbars. Moreover, the first and second dielectric strips can be on a surface of the layer, have a first portion under the IDT fingers and have a second portion extending into a gap between the margins and the busbars.

Abstract: An acoustic resonator is provided that includes a first piezoelectric layer of a material with a first crystallographic orientation and a second piezoelectric layer coupled to the first piezoelectric layer and comprising a material with a second crystallographic orientation, such that a piezoelectric tensor of the second piezoelectric layer is an opposite polarity to a piezoelectric tensor of the fist piezoelectric layer. Moreover, an interdigital transducer (IDT) including interleaved fingers is disposed on a surface of the first piezoelectric layer; and a first dielectric coating layer is disposed over the IDT and the first piezoelectric layer.

Abstract: Acoustic filters devices and methods of making the same. A filter device includes a first plurality of acoustic resonators including at least one first series resonator and at least one first shunt resonator. The at least one first series resonator and the at least one first shunt resonator are acoustically coupled along a first shared acoustic track.