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 wave resonator includes a piezoelectric body and electrode fingers. The electrode fingers are positioned on the piezoelectric body and arrayed in a propagation direction of acoustic waves. The electrode fingers include a first and second electrode finger groups. Electrode fingers are formed between adjacent two of the electrode fingers of the other electrode group. A duty ratio of the electrode fingers of the first and second electrode finger groups is gradually changed along one of opposite directions specifying the propagation direction by first and second change amounts, respectively which are different, and in the opposite direction. In a region in which the electrode fingers are positioned, a pitch between the electrode fingers is changed to cancel an effect of a difference in the duty ratio of the electrode fingers on a difference in resonance frequency.

Abstract: A composite filter device includes a piezoelectric substrate, a transmission filter, a reception filter, a first capacitance element, and a second capacitance element. The transmission filter includes a first parallel arm resonator connected to a first reference potential electrode. The reception filter includes a second parallel arm resonator connected to a second reference potential electrode. The first capacitance element is connected between a signal line in the reception filter and the first reference potential electrode. The second capacitance element is connected to the signal line and the second reference potential electrode in the reception filter.

Abstract: Filter devices and fabrication methods are disclosed. A filter device includes a piezoelectric plate and a conductor pattern on a front surface of the piezoelectric plate. The conductor pattern includes interdigital transducers (IDTs) of a plurality of transversely-excited film bulk acoustic resonators (XBARs) and a plurality of conductors connecting the plurality of XBARs in a ladder filter circuit architecture. The plurality of conductors includes a first conductor adjacent to a second conductor. An opening is provided through the piezoelectric plate between the first conductor and the second conductor.

Abstract: Disclosed are white space communications systems for wideband communications over TVWS bands. The white space communications systems include tunable frequency filters for providing non-contiguous coverage according to WSDB requirements blocking segments associated with occupied TV channels.

Abstract: A surface acoustic wave device has a piezoelectric substrate having a cut angle (e.g., the piezoelectric angle is cut so as to have a crystal orientation) that allows the surface acoustic wave device to operate as a longitudinally leaky surface acoustic wave device that confines the acoustic wave energy within the piezoelectric substrate and that has less propagation attenuation and a higher electromechanical coupling coefficient k2.

Abstract: The device includes an acoustic wave filter element, and a first resonator. The acoustic wave filter element includes interdigitated input electrodes and output electrodes located on a top surface of a piezoelectric layer and a counter-electrode on a bottom surface of the piezoelectric layer. The acoustic wave filter element provides a response with a sideband at a sideband frequency range. The first resonator includes a first resonator electrode on the top surface of the piezoelectric layer and a first resonator counter-electrode on the bottom surface of the piezoelectric layer. The first resonator has a first notch in resonator impedance at a first frequency. The first resonance frequency is tuned to fall within the sideband frequency range to suppress the sideband by depositing a first mass load on top of the first resonator electrode to reduce the first resonance frequency, or partly removing the first resonator electrode to increase the first resonance frequency.

Abstract: An acoustic resonator device includes a portion of a piezoelectric plate is a diaphragm spanning a cavity in a substrate. 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 fingers extending alternately from the first and second busbars, first and second reflector elements proximate and parallel to a first finger of the interleaved fingers, and third and fourth reflector element proximate and parallel to a last finger of the interleaved fingers. Overlapping portions of the interleaved fingers and the first to fourth reflector elements are on the diaphragm. pr1 is a center-to-center distance of the first and second reflector elements and a center-to-center distance of the third and fourth reflector elements, p is a pitch of the interleaved fingers, and 1.1p?pr1?1.5p.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave device that includes a multi-layer raised frame structure. The multi-layer raised frame structure includes a first raised frame layer positioned between a first electrode and a second electrode of the bulk acoustic wave device. The first raised frame layer has a lower acoustic impedance than the first electrode. The first raised frame layer and the second raised frame layer overlap in an active region of the bulk acoustic wave device. Related filters, multiplexers, packaged modules, wireless communication devices, and methods are disclosed.

Abstract: An acoustic resonator device includes a diaphragm including a portion of the piezoelectric plate spanning a cavity in a substrate. 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 fingers, wherein the plurality of interleaved fingers extend alternately from the first and second busbars, overlapping portions of the plurality of interleaved fingers on the diaphragm. The conductor pattern also includes first and second reflector elements on the diaphragm proximate and parallel to a first finger of the plurality of interleaved fingers, and third and fourth reflector element on the diaphragm proximate and parallel to a last finger of the plurality of interleaved fingers.

Abstract: A substrate that includes at least one dielectric layer and an inductive coupler formed in the at least one dielectric layer. The inductive coupler includes a first inductor and a second inductor. The first inductor is formed in the at least one dielectric layer. The first inductor is configured to be electrically coupled to a transmitter filter and an antenna. The second inductor is formed in the at least one dielectric layer. The second inductor is configured to be electrically coupled to the transmitter filter and ground. The second inductor is configured to provide a path to ground for a rejected signal having a rejected frequency. The second inductor is configured such that the rejected signal traveling through the second inductor causes the first inductor to generate an induced signal that counteracts a leakage signal traveling through the transmission filter.

Abstract: A substrate that includes an encapsulation layer, a first acoustic resonator, a second acoustic resonator, at least one first dielectric layer, a plurality of first interconnects, at least one second dielectric layer, and a plurality of second interconnects. The first acoustic resonator is located in the encapsulation layer. The first acoustic resonator includes a first piezoelectric substrate comprising a first thickness. The second acoustic is located in the encapsulation layer. The second acoustic resonator includes a second piezoelectric substrate comprising a second thickness that is different than the first thickness. The at least one first dielectric layer is coupled to a first surface of the encapsulation layer. The plurality of first interconnects is coupled to the first surface of the encapsulation layer. The plurality of first interconnects is located at least in the at least one first dielectric layer.

Abstract: To achieve an elastic wave element with excellent electrical characteristics. An elastic wave resonator includes a piezoelectric substrate including a piezoelectric body and an IDT electrode, a support substrate, and a first intermediate layer. In the first intermediate layer, an atomic ratio of a metal element is larger than an atomic ratio of a metal element in the piezoelectric body, and an atomic ratio of oxygen is smaller than an atomic ratio of oxygen in the piezoelectric body. A thickness of the piezoelectric body is equal to or less than five times a maximum pitch of electrode fingers of the IDT electrode.

Abstract: Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a multi-layer mass loading strip. The mass loading strip has a density that is higher than a density of the temperature compensation layer. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can include a first layer for adhesion and a second layer for mass loading. The mass loading strip can suppress a transverse mode.

Abstract: Aspects of this disclosure relate to an acoustic wave filter with shunt bulk acoustic wave resonators. In some embodiments, the acoustic wave filter is a band pass filter having a pass band. One of the shunt bulk acoustic wave resonators can contribute to forming an upper edge of the pass band. That shunt bulk acoustic wave resonator can be smaller than another shunt bulk acoustic wave resonator of the acoustic wave filter.

Abstract: An acoustic wave filter package is disclosed. The acoustic wave filter package can include a first acoustic wave filter, a second acoustic wave filter, and a shared node. The first acoustic wave filter is configured to filter a first radio frequency signal. The first acoustic wave filter has a first shunt resonator. The second acoustic wave filter is configured to filter a second radio frequency signal. The second acoustic wave filter having a second shunt resonator. The first and second shunt resonators are electrically coupled to ground at the shared node.

Abstract: An acoustic wave device includes a piezoelectric layer and an interdigital transducer electrode disposed over the piezoelectric layer. The interdigital transducer electrode is thicker in a center region of the interdigital transducer electrode than in a gap region of the interdigital transducer electrode to thereby reduce a mass loading of the interdigital transducer electrode in the gap region. The interdigital transducer electrode has a layer of less dense material disposed of a layer of more dense material.

Abstract: Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is 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 (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of an edge of the diaphragm is at an oblique angle to the fingers.

Abstract: An acoustic wave filter device includes first and second signal terminals, a series arm circuit connected between the first and second signal terminals and including series arm resonators, and a parallel arm circuit connected in series between the series arm circuit and a ground potential and including at least one parallel arm resonator. The series arm resonators include first and second series arm resonators having different anti-resonant frequencies from each other. The anti-resonant frequency of the first series arm resonator is lowest among anti-resonant frequencies of the plurality of series arm resonators. The first series arm resonator and the second series arm resonator are connected to each other without another circuit element interposed therebetween.

Abstract: A high frequency circuit includes a main module and a diversity module. The main module includes a duplexer that transmits and receives a signal of a first communication band of a first communication system. The diversity module includes a duplexer that transmits and receives a signal of a second communication band of a second communication system, a reception filter that uses a reception band of the first communication band of the first communication system as a pass band, a power amplifier, a low noise amplifier, and a switch that exclusively switches between connection between a reception filter and the low noise amplifier and connection between the reception filter and the low noise amplifier. The first communication band and the second communication band have the same frequency band.

Abstract: Acoustic filters are disclosed. A bandpass filter has a passband between a lower band edge and an upper band edge. The bandpass filter includes a plurality of transversely-excited film bulk acoustic resonators (XBARs) connected in a ladder filter circuit. The plurality of XBARs includes at least one lithium tantalate XBAR and at least one lithium niobate XBAR.

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: Aspects of this disclosure relate to an acoustic wave device having an overtone mode as a main mode. The acoustic wave device is sufficiently asymmetric on opposing sides of a piezoelectric layer over an acoustic reflector such that the main mode of the acoustic wave device is the overtone mode.

Abstract: An electronic component includes a first main body including a plurality of dielectric layers stacked together, and a second main body mounted to the first main body. The second main body includes a first circuit section and a second circuit section that are each constituted by using at least one acoustic wave element and are electrically separated from each other. The first main body includes first to third ground conductor lavers located between the first and second circuit sections when seen in a Z direction.

Abstract: Aspects of this disclosure relate to a multiplexer with an acoustic assisted trap circuit. The multiplexer includes a first acoustic wave filter and a second acoustic wave filter. The first acoustic wave filter can include a bulk acoustic wave resonator. The second acoustic wave filter can include a surface acoustic wave resonator and an impedance network. The surface acoustic wave resonator and the impedance network can together provide a trap for a harmonic associated with the first acoustic wave filter.

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: An acoustic wave device includes a substrate including a piezoelectric layer, first and second resonators on the substrate, and a shared reflector. The second resonator is located on the substrate adjacent to the first resonator and has different frequency characteristics than the first resonator. The shared reflector is located on the substrate between the first resonator and the second resonator and is a reflector for both the first resonator and the second resonator. The first resonator includes a first interdigital transducer electrode with electrode fingers positioned with a first pitch. The second resonator includes a second interdigital transducer electrode with electrode fingers positioned with a second pitch. A lower limit frequency of a stop band of the shared reflector is between a lower limit frequency of a stop band of the first resonator and a lower limit frequency of a stop band of the second resonator.

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: An acoustic wave device includes a piezoelectric layer, the piezoelectric layer being a rotated Y-cut lithium niobate substrate or an X-cut lithium tantalate substrate; an upper conductive layer having a substantially consistent density, on or over the upper surface of the piezoelectric layer; a lower conductive layer having a substantially consistent density, on or below the lower surface of the piezoelectric layer; and a first additional film having a substantially consistent density, wherein at least one of the upper and lower conductive layers is mainly made of ruthenium, chrome, copper, molybdenum, tungsten, tantalum, platinum, rhodium, or iridium, and wherein at least a part of the first additional film is in the resonance region in the plan view, and the density of the first additional film is equal to or less than the density of aluminum.

Abstract: The present disclosure provides a radio frequency filter, including: a substrate; a supporting electrode protruded on a front surface of the substrate; and a thin film structure formed on the substrate and spaced with the substrate by the supporting electrode. An end surface of a top end of the supporting electrode is in sealing contact with a front surface of the thin film structure.

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: A surface acoustic wave device includes a piezoelectric substrate formed from a Ca3Ta(Ga1-xAlx)3Si2O14 single crystal, and an interdigital electrode formed on the surface of the piezoelectric substrate and formed from Al. The interdigital electrode is configured to generate a Love-wave-type SH wave on the surface of the piezoelectric substrate. A normalized film thickness obtained by dividing the film thickness of the interdigital electrode by the wavelength of the Love-wave-type SH wave is 0.16 or less.

Abstract: An acoustic wave device is disclosed. The acoustic wave device includes a piezoelectric layer, an interdigital transducer electrode positioned over the piezoelectric layer, and an anti-refection layer over a conductive layer of the interdigital transducer electrode. The conductive layer can include aluminum, for example. The anti-reflection layer can include silicon. The anti-reflection layer can be free from a material of the interdigital transducer electrode. The acoustic wave device can further include a temperature compensation layer positioned over the anti-reflection layer in certain embodiments.

Abstract: An electronic component includes a mounting substrate, and first and second devices each including a functional element. The first device is spaced apart from and faces the mounting substrate. The second device is located on the mounting substrate and faces the first device. A functional element of the first device is located on a first surface facing the second device, in the first device. A functional element of the second device is located on a second surface facing the first device, in the second device.

Abstract: An acoustic wave device includes a substrate, a first resonator, a second resonator, and a shared reflector. The second resonator is adjacent to the first resonator and has different frequency characteristics different than the first resonator. The first resonator includes a first interdigital transducer electrode. The second resonator includes a second interdigital transducer electrode. The shared reflector has frequency characteristics that are the same as both frequency characteristics of the first resonator and frequency characteristics of the second resonator or between the frequency characteristics of the first resonator and the frequency characteristics of the second resonator. a higher-order mode frequency of the first resonator and a higher-order mode frequency of the second resonator coincides.

Abstract: A filter includes a series resonator including a first piezoelectric layer and first electrodes, and a parallel resonator including a second piezoelectric layer and second electrodes. Each of the first and second piezoelectric layers is a monocrystalline lithium niobate layers, has an X-axis orientation in a planar direction, and has a thickness direction in a direction obtained by a 105° rotation of a +Z-axis orientation toward a +Y-axis orientation. The first electrodes face each other across the first piezoelectric layer to form a first resonance region and are extracted from the first resonance region in a direction substantially parallel to the X-axis orientation of the first piezoelectric layer. The second electrodes face each other across the second piezoelectric layer to form a second resonance region and are extracted from the second resonance region in a direction substantially orthogonal to the X-axis orientation of the second piezoelectric layer.

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: A filter includes first and second shunt resonators, at least one series resonator connected to the first and second shunt resonators in a ladder filter circuit, and a first ground contact pad. The first shunt resonator has two or more first sub-resonators and the second shunt resonator has two or more second sub-resonators. At least one first sub-resonator and at least one, but less than all, of the two or more second sub-resonators are connected to the first ground contact pad.

Abstract: Disclosed is a Bulk Acoustic Wave (BAW) filter structure with a conductive bridge forming an electrical loop with an electrode for reduced electrical losses. In exemplary aspects disclosed herein, the BAW filter structure includes a transducer with electrodes, a piezoelectric layer between the electrodes, and at least one conductive bridge offset from at least a portion of one of the electrodes by an insulating volume. The conductive bridge forms a first electrical loop between a medial end and a distal end of the electrode. Such a configuration reduces electrical resistance, heat resistance, and/or ohmic losses for improved electrical loss of the BAW filter structure.

Abstract: A surface acoustic wave device comprising a base substrate, a piezoelectric layer and an electrode layer in between the piezoelectric layer and the base substrate, a comb electrode formed on the piezoelectric layer comprising a plurality of electrode means with a pitch p, defined asp=A, with A being the wavelength of the standing acoustic wave generated by applying opposite potentials to the electrode layer and comb electrode, wherein the piezoelectric layer comprises at least one region located in between the electrode means, in which at least one physical parameter is different compared to the region underneath the electrode means or fingers. A method of fabrication for such surface acoustic wave device is also disclosed. The physical parameter may be thickness, elasticity, doping concentration of Ti or number of protons obtained by proton exchange.

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: An acoustic wave component is disclosed. The acoustic wave component can include a bulk acoustic wave resonator and a surface acoustic wave device. The bulk acoustic wave resonator can include a first portion of a ceramic substrate, a first piezoelectric layer positioned on the ceramic substrate, and electrodes positioned on opposing sides of the first piezoelectric layer. The surface acoustic wave device can include a second portion of the ceramic substrate, a second piezoelectric layer positioned on the ceramic substrate, and an interdigital transducer electrode on the second piezoelectric layer.

Abstract: A surface elastic wave filter has resonant cavities and comprises a composite substrate formed of a base substrate and a piezoelectric upper layer; at least one input electroacoustic transducer and an output electroacoustic transducer, arranged on the upper layer, and at least one internal reflecting structure, arranged between the input electroacoustic transducer and the output electroacoustic transducer. The internal reflecting structure comprises a first structure comprising at least one reflection grating having a first period and a second structure comprising at least one reflection grating having a second period, the first period being greater than the second period.

Abstract: A filter device includes first and second filters respectively having first and second passbands, the second passband being in a frequency range higher than the first passband. The first and second filters are commonly connected to a common terminal. In the first filter, multiple parallel arm resonators define a parallel connection unit in which the parallel arm resonators are connected in parallel with no serial arm resonators interposed therebetween. The parallel arm resonators in the parallel connection unit include first and second parallel arm resonators having anti-resonant frequencies different from each other. In combined impedance-frequency characteristics of the parallel arm resonators in the parallel connection unit, at least one anti-resonant frequency other than a highest anti-resonant frequency is equal to or higher than 2f1min?f2min and equal to or lower than 2f1max?f2max.

Abstract: Aspects of this disclosure relate to multiplexers with that include an acoustic wave resonator. The acoustic wave filter includes a plurality of acoustic wave resonators of a first type and a shunt acoustic wave resonator of a second type. The shunt acoustic wave resonator of the second type has lower second harmonic distortion than the acoustic wave resonators of the first type. The shunt acoustic wave resonator of the second type has a resonant frequency in a passband of another filter of the multiplexer. Related radio frequency modules, wireless communication devices, and methods are also disclosed.

Abstract: A radio-frequency module includes a mounting substrate including a ground electrode layer formed by a planar wiring pattern; multiple ground terminals, which are multiple external connection terminals that are arranged on a first main surface of the mounting substrate and that are set to ground potential; and a first radio-frequency component (for example, a reception filter and/or a low noise amplifier) mounted on the first main surface. The multiple ground terminals are arranged at an outer periphery side of the first main surface with respect to the first radio-frequency component and are connected to the ground electrode layer. In a plan view of the mounting substrate, at least part of the first radio-frequency component is overlapped with the ground electrode layer.

Abstract: Aspects of this disclosure relate to multiplexers with acoustic wave resonators. The multiplexer includes a first filter and a second filter. The first filter includes a plurality of bulk acoustic wave resonators and a shunt surface acoustic wave resonator. The shunt acoustic wave resonator can have a resonant frequency in a passband of the second filter. The passband of the second filter is below a passband of the first filter. In certain applications, the first filter is a receive filter and the second filter is a transmit filter.

Abstract: Devices and methods related to wideband multiplexer for radio-frequency (RF) applications. In some embodiments, a multiplexer may include a common path configured to receive a plurality of RF signals. The multiplexer may further include a first path having an output coupled to the common path and configured to provide a band-pass response for a frequency band BX. The multiplexer may further include a second path having an output coupled to the common path such that RF signals in the first and second paths are combined and routed through the common path. The second path may be configured to provide a band-stop response for the frequency band BX such that the common path includes a wideband response that includes the frequency band BX and one or more other frequency bands.

Abstract: A surface acoustic wave device includes a piezoelectric substrate and a pair of IDT electrodes. The pair of IDT electrodes includes a pair of busbars and multiple electrode fingers. The pair of busbars are formed on the piezoelectric substrate. The electrode fingers extend in a comb shape from each of the busbars toward the opposing busbar. The pair of IDT electrodes has an intersection region as a region where the electrode fingers connected to one busbar and the electrode fingers connected to another busbar are intersected when viewed along an arrangement direction of the electrode fingers. The electrode finger in a non-intersection region outside the intersection region has a thickness thinner than a thickness of the electrode finger in the intersection region.

Abstract: An acoustic filter device includes a transversely-excited film bulk acoustic resonator (XBAR) including a plurality of sub-resonators, and conductors connecting the plurality of sub-resonators in series between a first node and a second node. At least one of the conductors connects two of the plurality of sub-resonators and has a shape that minimizes an area of the at least one conductor.