Abstract: An acoustic wave device is provided that includes a piezoelectric layer and first and second resonators. The first resonator includes a first functional electrode and a first dielectric film on the piezoelectric layer. The second resonator includes a second functional electrode and a second dielectric film on the piezoelectric layer. The piezoelectric layer includes first and second resonator portions respectively including portions of the first and second resonators. Moreover, a resonant frequency of the first resonator is lower than that of the second resonator. A thickness of the first resonator portion is greater than that of the second resonator portion, and ts1/tp1?ts2/tp2 is satisfied, where tp1, tp2, ts1, and ts2 are respectively thicknesses of the first and second resonator portions and the first and second dielectric films.

Abstract: A filter device is provided that includes a substrate, a piezoelectric plate attached to the substrate; interdigital transducers (IDTs) of a plurality of resonators, respectively, that each have interleaved fingers at respective diaphragms of the one piezoelectric plate disposed over one or more cavities; and a dielectric layer over at least one surface of the respective diaphragms. For at least two resonators, the dielectric layer has a thickness distribution that includes a first thickness layer and a second thickness layer over the first thickness layer, and the second thickness layer of a first resonator of the at least two resonators has a coverage distribution over the first thickness layer that is different than a coverage distribution of a second resonator of the at least two resonators.

Abstract: An acoustic resonator has a piezoelectric plate having first and second surfaces, the second surface facing a substrate, and a diaphragm of the piezoelectric plate spanning a cavity. A conductor pattern is formed on at least one of the first and second surfaces and has an interdigital transducer (IDT) having interleaved fingers on the diaphragm portion of the piezoelectric plate. At least one of a pitch of the interleaved IDT fingers or a mark of the interleaved IDT fingers varies over an area of the IDT to compensate for process-induced distortion of the diaphragm portion of the piezoelectric plate.

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: Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

Abstract: Bandpass filters are disclosed. A bandpass filter includes a plurality of series resonators and a plurality of shunt resonators. The series resonators are connected in series between a first port and a second port. The plurality of series resonators includes a first series resonator and a second series resonator connected at a node. The plurality of shunt resonators includes a first shunt resonator coupled between the node and a ground. A capacitor bridges the first and second series resonators.

Abstract: Bandpass filters are disclosed. A bandpass filter includes a plurality of series resonators and a plurality of shunt resonators. The series resonators are connected in series between a first port and a second port. The plurality of series resonators includes a first series resonator and a second series resonator connected at a node. The plurality of shunt resonators includes a first shunt resonator coupled between the node and a ground. A capacitor bridges the first and second series resonators.

Abstract: Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

Abstract: An acoustic resonator device is formed using a sacrificial layer and a front side etched cavity by forming a recess in a silicon substrate with a trap-rich top layer and filling the recess with sacrificial silicon nitride. A bonding oxide (BOX) layer is formed over the trap-rich layer and the sacrificial silicon nitride filled recess and a piezoelectric plate is bonded to the BOX layer. The sacrificial silicon nitride is then removed to form a cavity by using an etchant introduced through holes in the piezoelectric plate and BOX layer without removing the BOX layer from over the cavity.

Abstract: An acoustic resonator is fabricated by bonding a first piezoelectric plate to a substrate and spans locations for a first and second cavity in the substrate. A top surface of the first plate is planarized to a first thickness. A bonding layer is formed on the first piezoelectric plate and spans the first and second cavity locations. A second piezoelectric plate is bonded to the bonding layer and spans the first and second cavity locations. A top surface of the second plate is planarized to a second thickness. A portion of the second piezoelectric plate spanning the second cavity location is etched away to form a first membrane over the first cavity location and a second membrane over the second cavity location. Interdigital transducers are formed on the first and second membranes over the first and second cavity location to form a first and second resonator on the same die.

Abstract: 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.

Abstract: Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

Abstract: Bandpass filters are disclosed. A bandpass filter includes a plurality of series resonators and a plurality of shunt resonators. The series resonators are connected in series between a first port and a second port. The plurality of series resonators includes a first series resonator and a second series resonator connected at a node. The plurality of shunt resonators includes a first shunt resonator coupled between the node and a ground. A capacitor bridges the first and second series resonators.

Abstract: An absorptive bandstop filter includes at least two frequency-dependent networks, one of which constitutes a bandpass filter, that form at least two forward signal paths between an input port and an output port and whose transmission magnitude and phase characteristics are selected to provide a relative stopband bandwidth that is substantially independent of the maximum attenuation within the stopband and/or in which the maximum attenuation within the stopband is substantially independent of the unloaded quality factor of the resonators. The constituent network characteristics can also be selected to provide low reflection in the stopband as well as in the passband. The absorptive bandstop filter can be electrically tunable and can substantially maintain its attenuation characteristics over a broad frequency tuning range.

Abstract: A dual-mode dielectric-resonator-loaded cavity filter comprises a generally cylindrical cavity, at least two longitudinally-spaced dielectric resonator elements coaxially aligned within the cavity, and at least one coupling obstacle disposed between the resonators and extending a distance from the cavity wall. The coupling obstacles are preferably conductive and are electrically connected to the cavity wall. However, the obstacles may be constructed of a dielectric material in some applications. Each obstacle may be aligned with one of the reference planes corresponding to a resonant mode of the resonators to effectively control or reduce the coupling between the parallel resonant modes of adjacent resonators. The reduction in coupling between resonant modes of adjacent resonators allows large coupling differentials to be produced, allowing a filter designer to implement a wide variety of high-performance filters without expensive irises.