Abstract: Acoustic resonators and filters are disclosed. An acoustic resonator includes a substrate, a piezoelectric plate and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. A conductor pattern on a front surface of the piezoelectric plate includes an interdigital transducer (IDT). The IDT includes a first busbar, a second busbar, and interleaved parallel fingers extending alternately from the first and second busbars. The fingers include a first finger and a last finger at opposing ends of the IDT. A first reflector element is proximate and parallel to the first finger and a second reflector element is proximate and parallel to the last finger. A distance pr between the first reflector element and the first finger and between the second reflector element and the last finger is greater than a pitch p of the IDT.

Abstract: A 5 GHz Wi-Fi bandpass filter includes a ladder filter circuit with two or more shunt transversely-excited film bulk acoustic resonators (XBARs) and two or more series XBARs. Each of the two or more shunt XBARS includes a diaphragm having an LN-equivalent thickness greater than or equal to 360 nm, and each of the two or more series XBARS includes a diaphragm having an LN-equivalent thickness less than or equal to 375 nm.

Abstract: Acoustic resonators, filters and methods of making resonators are disclosed. An acoustic resonator includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. An interdigital transducer (IDT) on a front surface of the piezoelectric plate includes first and second busbars and a plurality of interleaved fingers extending alternately from the first and second busbars. At least a portion of the first busbar contacts the substrate through an opening in the piezoelectric plate and acoustic Bragg reflector.

Abstract: A bulk acoustic resonator is provided that includes a substrate having a surface; a piezoelectric layer attached to the surface of the substrate via a bonding oxide (BOX) layer over the surface of the substrate; a conductor pattern including an interdigital transducer (IDT) that has interleaved fingers on a surface of the piezoelectric layer; at least one contact pad disposed at a selected location over the surface of the substrate and that is electrically connected to the IDT; and an electrically isolating layer between the at least one contact pad and the surface of the substrate. Moreover, at least a portion of the piezoelectric layer is absent between the at least one contact pad and the surface of the substrate.

Abstract: Acoustic filters, resonators and methods are disclosed. An acoustic filter device includes a substrate; a piezoelectric layer attached to the substrate, wherein at least a portion of the piezoelectric layer is disposed over a cavity of the acoustic resonator device; and an interdigital transducer (IDT) on a surface of the piezoelectric layer, the IDT including interleaved fingers extending at least over the portion of the piezoelectric layer disposed over the cavity. The cavity has at least one rounded corner, and a portion of interleaved fingers extend from at least one busbar. Moreover, at least a portion of the rounded corner of the cavity is under the at least one busbar in a plan view of the piezoelectric layer.

Abstract: A bandpass filter is provided that includes a ladder filter circuit with at least one shunt transversely-excited film bulk acoustic resonators (XBAR) and at least one series XBAR. Each of the XBARs includes a diaphragm having an LN-equivalent thickness greater than or equal to 360 nm, and each of the XBARs includes a diaphragm having an LN-equivalent thickness less than or equal to 375 nm.

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 device may include a substrate that includes a base and an intermediate layer. A device may include a piezoelectric layer supported by the substrate except for a portion of the piezoelectric layer forming a diaphragm that spans a helium filled cavity that extends at least partially in the intermediate layer. A device may include an interdigital transducer (IDT) at a surface of the piezoelectric layer and having interleaved fingers on the diaphragm that have a thickness that is less than 0.5 times a thickness of the diaphragm and greater than 0.2 times the thickness of the diaphragm, wherein one of the base and the intermediate layer of the substrate defines a bottom surface of the helium filled cavity that faces the diaphragm such that a cavity depth is between 1.0 ?m to 6.0 ?m.

Abstract: Acoustic filters, resonators and methods are disclosed. An acoustic filter device includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer is formed on the front surface of the piezoelectric plate with interleaved fingers of the IDT disposed on the diaphragm. At least a portion of a perimeter of the cavity is curved and at least one end zone of the perimeter of the cavity is round.

Abstract: An acoustic resonator device with low thermal impedance has a substrate and a single-crystal piezoelectric plate having a back surface attached to a top surface of the substrate via a bonding oxide (BOX) layer. An interdigital transducer (IDT) formed on the front surface of the plate has interleaved fingers disposed on the diaphragm, the overlapping distance of the interleaved fingers defining an aperture of the resonator device. Contact pads are formed at selected locations over the surface of the substrate to provide electrical connections between the IDT and contact bumps to be attached to the contact pads. The piezoelectric plate is removed from at least a portion of the surface area of the device beneath each of the contact pads to provide lower thermal resistance between the contact bumps and the substrate.

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: Tiled filters are disclosed. A filter includes an n×m array of sub-filters, where n is a number of sub-filters in parallel and m is a number of sub-filters in series. n and m are non-zero positive integers and at least one of n and m is greater than one. All of the nm sub-filters are bandpass filters with substantially the same passbands.

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: A filter is provided that a piezoelectric layer, an interdigital transducers (IDT) having interleaved fingers at the piezoelectric layer, contact pads at the piezoelectric layer and electrically coupled to the IDT, and a printed circuit board (PCB). The PCB includes a plurality of layers including at least one layer that includes a first portion and a second portion that is physically separate from the first portion with a gap therebetween. Moreover, a plurality of electrical contacts are provided on a top layer of the plurality of layers that is facing the piezoelectric layer, with the plurality of electrical contacts electrically coupled to the plurality of contact pads, respectively.

Abstract: An acoustic resonator device with low thermal impedance has a substrate and a single-crystal piezoelectric plate having a back surface attached to a top surface of the substrate via a bonding oxide (BOX) layer. An interdigital transducer (IDT) formed on the front surface of the plate has interleaved fingers disposed on the diaphragm, the overlapping distance of the interleaved fingers defining an aperture of the resonator device. Contact pads are formed at selected locations over the surface of the substrate to provide electrical connections between the IDT and contact bumps to be attached to the contact pads. The piezoelectric plate is removed from at least a portion of the surface area of the device beneath each of the contact pads to provide lower thermal resistance between the contact bumps and the substrate.

Abstract: Acoustic resonator devices and acoustic filter devices. An acoustic resonator includes a piezoelectric plate having front and back surfaces. A portion of the back surface is attached to a substrate. The piezoelectric plate comprises a diaphragm spanning a cavity. A conductor pattern is formed on the front surface. The conductor pattern includes a multi-mark interdigital transducer (IDT), with fingers of the IDT on the diaphragm.

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: Radio frequency filters are disclosed. A bandpass filter is discloses that includes one first bulk acoustic resonator on a first chip including a first piezoelectric layer having an LN-equivalent thickness less than or equal to 535 nm; a second bulk acoustic resonator on a second chip including a second piezoelectric layer having a thickness greater than the LN-equivalent thickness of the piezoelectric layer on the first chip; and a circuit card coupled to the first chip and the second chip and that electrically connects the first chip to the second chip.

Abstract: An acoustic resonator device includes a diaphragm a diaphragm comprising a portion of a piezoelectric plate spanning a cavity. A conductor pattern on a surface of the piezoelectric plate includes an interdigital transducer (IDT) with a first busbar, a second busbar, and a plurality of interleaved IDT fingers extending alternately from the first and second busbars. Overlapping portions of the plurality of interleaved fingers are on the diaphragm. The conductor pattern also includes a first reflector element on the diaphragm proximate and parallel to a first IDT finger, and a second reflector element on the diaphragm proximate and parallel to a last IDT finger. A center-to-center spacing of the first reflector element and the first IDT finger and the second reflector element and the last IDT finger is greater than an average center-to-center spacing between all adjacent pairs of IDT fingers.