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.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate supported by the substrate. A portion of the piezoelectric plate suspended across a cavity in the substrate forms a diaphragm. A decoupling dielectric layer is on a front surface of the diaphragm. An interdigital transducer (IDT) has interleaved fingers on the decoupling dielectric layer over the diaphragm. The IDT and piezoelectric plate are configured such that a radio frequency signal applied to the IDT excites shear acoustic waves in the diaphragm.

Abstract: A filter device is provided that includes a plurality of bulk acoustic resonators that each includes a piezoelectric layer; a conductor pattern on the piezoelectric layer and including an interdigital transducer (IDT) having a first plurality of fingers extending from a first busbar and a second plurality of fingers extending from the second busbar, such that the first plurality of fingers and the second plurality of fingers are interleaved with each other; a dielectric strip that overlaps a margin of the first plurality of fingers and that extends into a gap between ends of the first plurality of fingers and the second busbar. Moreover, a thickness ts of the dielectric strip a first bulk acoustic resonator of the plurality of bulk acoustic resonators is different than a thickness ts of the dielectric strip of a second bulk acoustic resonator of the plurality of bulk acoustic resonators.

Abstract: Acoustic resonators, filters, and methods. An acoustic resonator includes a substrate, a piezoelectric plate, and a diaphragm including a portion of the piezoelectric plate spanning a cavity in a substrate. An interdigital transducer (IDT) on a front surface of the piezoelectric plate includes first and second sets of interleaved interdigital transducer (IDT) fingers extending from first and second busbars respectively. The interleaved IDT fingers extend onto the diaphragm. Overlapping portions of the interleaved IDT fingers define an aperture of the acoustic resonator. First and second dielectric strips are on the front surface of the piezoelectric plate. Each dielectric strip has a first portion under the IDT fingers in a respective margin of the aperture and a second portion extending into a gap between the respective margin and the respective busbar.

Abstract: Acoustic resonators, filters, and methods. An acoustic resonator includes a substrate, a piezoelectric plate, and a diaphragm including a portion of the piezoelectric plate spanning a cavity in a substrate. An interdigital transducer (IDT) on a front surface of the piezoelectric plate includes first and second sets of interleaved interdigital transducer (IDT) fingers extending from first and second busbars respectively. The interleaved IDT fingers extend onto the diaphragm. Overlapping portions of the interleaved IDT fingers define an aperture of the acoustic resonator. First and second dielectric strips are on the front surface of the piezoelectric plate. Each dielectric strip has a first portion under the IDT fingers in a respective margin of the aperture and a second portion extending into a gap between the respective margin and the respective busbar.

Abstract: Acoustic resonators, filters, and methods. A filter includes a piezoelectric plate supported by a substrate; and three or more diaphragms of the piezoelectric plate spanning a respective cavity in the substrate. A conductor pattern on the plate 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. Sometimes, each of the resonators has 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. Other times, the first and second dielectric strips are on the front surface of the plate, have a first portion under the IDT fingers and have a second portion extending into a gap between the margins and the busbars.

Abstract: Diplexers, filter devices, and methods are disclosed. A diplexer includes a first chip comprising series resonators of a high band filter, a second chip comprising shunt resonators of the high band filter and series resonators of a low band filters, and a third chip comprising shunt resonators of the low band filter. The series resonators and the shunt resonators of the high band filter are decoupled transversely-excited film bulk acoustic resonators (DXBARs). The series resonators and the shunt resonators of the low band filter are transversely-excited film bulk acoustic resonators (XBARs).

Abstract: An acoustic resonator device is provided that includes a substrate; a piezoelectric plate having front and back surfaces, the back surface attached to the substrate; a decoupling dielectric layer on the front surface of the piezoelectric plate; and an interdigital transducer (IDT) on the decoupling dielectric layer such that interleaved fingers of the IDT are over a portion of the piezoelectric plate that is over a cavity. Moreover, a thickness of the interleaved fingers is greater than or equal to 0.6 times a thickness of the piezoelectric plate and less than or equal to 1.7 times the thickness of the piezoelectric plate.

Abstract: A filter device is proved that includes a first chip having a first interdigital transducer (IDT) of a first bulk acoustic resonator at a first piezoelectric plate, the first IDT disposed on a portion of the first piezoelectric plate over a first cavity of the first bulk acoustic resonator, and a second chip having a second IDT of a second bulk acoustic resonator formed at a second piezoelectric plate, the second IDT disposed on a portion of the second piezoelectric plate over a second cavity of the second bulk acoustic resonator. The filter device includes a circuit card coupled to the first chip and the second chip. A thickness of the first piezoelectric plate is greater than a thickness of the second piezoelectric plate.

Abstract: An acoustic filter device is provided that includes a substrate and a piezoelectric layer having a first portion spanning a first cavity of the acoustic filter device and a second portion spanning a second cavity of the acoustic filter device. Moreover, a decoupling dielectric layer is on a surface of the first and second portions of the piezoelectric layer. The decoupling dielectric layer has a first thickness td1 on the first portion and a second thickness td2 on the second portion. The second thickness td2 being greater than the first thickness td1. First and second interdigital transducers (IDTs) are provided with interleaved fingers of the first IDT on the decoupling dielectric layer over the first portion of the piezoelectric layer and interleaved fingers of the second IDT on the decoupling dielectric layer over the second portion of the piezoelectric layer.

Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a piezoelectric plate having front and back surfaces, the back surface attached to the substrate. A decoupling dielectric layer is on the front surface of the piezoelectric plate. An interdigital transducer (IDT) is formed over the decoupling dielectric layer such that interleaved fingers of the IDT are over a portion of the piezoelectric plate suspended across a cavity formed in the substrate. A thickness of the interleaved fingers is greater than or equal to 1.17 times a thickness of the piezoelectric plate and less than or equal to 1.7 times the thickness of the piezoelectric plate.

Abstract: Acoustic resonators, filters, and methods. An acoustic resonator includes a substrate, piezoelectric plate, and a diaphragm comprising a portion of the piezoelectric plate spanning a cavity in a substrate. An interdigital transducer (IDT) on a front surface of the piezoelectric plate includes first and second sets of interleaved interdigital transducer (IDT) fingers extending from first and second busbars respectively. The interleaved IDT fingers are on the diaphragm. Overlapping portions of the interleaved IDT fingers define an aperture of the acoustic resonator. A first dielectric strip overlaps the IDT fingers in a first margin of the aperture and extends into a first gap between the first margin and the first busbar. A second dielectric strip overlaps the IDT fingers in a second margin of the aperture and extends into a second gap between the second margin and the second busbar.

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

Abstract: Filter devices and methods of fabrication are disclosed. An acoustic filter device includes a substrate and a piezoelectric plate, a first portion of the piezoelectric plate spanning a first cavity in the substrate and a second portion of the piezoelectric plate spanning a second cavity in the substrate. A decoupling dielectric layer on a front surface of the first and second portions of the piezoelectric plate has a first thickness td1 on the first portion and a second thickness td2, greater than the first thickness, on the second portion. Interleaved fingers of a first interdigital transducer (IDT) are on the decoupling dielectric layer over the first portion of the piezoelectric plate, and interleaved fingers of a second IDT are on the decoupling dielectric layer over the second portion of the piezoelectric plate.

Abstract: Acoustic resonator devices, filers, and methods. An acoustic resonator includes a substrate and a piezoelectric plate, a portion of the piezoelectric plate being a diaphragm spanning a cavity in the substrate. A conductor pattern on a front surface of the piezoelectric plate includes interleaved interdigital transducer (IDT) fingers connected alternately to first and second busbars. The interleaved IDT fingers are on the diaphragm, and the interleaved IDT fingers include at least a first pair of interleaved spiral IDT fingers.

Abstract: A radio frequency filter includes at least a first sub-filter and a second sub-filter connected in parallel between a first port and a second port. Each of the sub-filters has a piezoelectric plate having front and back surfaces, the back surface attached to a substrate, and portions of the piezoelectric plate forming diaphragms spanning respective cavities in the substrate. A conductor pattern is formed on the front surface of the plate, the conductor pattern includes interdigital transducers (IDTs) of a respective plurality of resonators, with interleaved fingers of each IDT disposed on a respective diaphragm of the plurality of diaphragms. A thickness of the portions of the piezoelectric plate of the first sub-filter is different from a thickness of the portions of the piezoelectric plate of the second sub-filter.

Abstract: Filter devices. A first chip includes a first interdigital transducer (IDT) of a first acoustic resonator formed on a surface of a first piezoelectric wafer having a first thickness, interleaved fingers of the first IDT disposed on a portion of the first piezoelectric wafer spanning a first cavity in a first base. A second chip includes a second IDT of a second acoustic resonator formed on a surface of a second piezoelectric wafer having a second thickness less than the first thickness, interleaved fingers of the second IDT disposed on a portion of the second piezoelectric wafer spanning a second cavity in a second base. A circuit card coupled to the first chip and the second chip includes at least one conductor for making an electrical connection between the first IDT and the second IDT.

Abstract: Acoustic resonator devices, filters, and methods. An acoustic resonator includes a substrate and a piezoelectric plate, a portion of the piezoelectric plate being a diaphragm spanning a cavity in the substrate. A conductor pattern on a front surface of the piezoelectric plate includes concentric interleaved interdigital transducer (IDT) fingers connected alternately to first and second busbars. The IDT fingers are on the diaphragm.

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.