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 glass substrate, a first piezoelectric layer positioned on the glass substrate, and electrodes positioned on opposing sides of the first piezoelectric layer. The surface acoustic wave device can include a second portion of the glass substrate, a second piezoelectric layer positioned on the glass substrate, and an interdigital transducer electrode on the second piezoelectric layer.

Abstract: One-way sound transmission devices include a planar, acoustically reflective substrate having an aperture that is traversed by an elastic membrane. On one face of the substrate, two resonators are symmetrically spaced apart from the membrane at a first distance, configured to enable constructive interference between the resonators and the membrane. On the opposite face of the substrate, two other resonators are symmetrically spaced apart from the membrane at a second, greater, distance, configured to enable destructive interference between the resonators and the membrane.

Abstract: An integrated circuit may include oscillator circuitry having a resonator formed from fin field-effect transistor (FinFET) devices. The resonator may include drive cells of alternating polarities and sense cells interposed between the drive cells. The resonator may be connected in a feedback loop within the oscillator circuitry. The oscillator circuitry may include an amplifier having an input coupled to the sense cells and an output coupled to the drive cells. The oscillator circuitry may also include a separate inductor and capacitor based oscillator, where the resonator serves as a separate output filter stage for the inductor and capacitor based oscillator.

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: A resonator is provided that includes a vibration portion having a first and second electrodes, a piezoelectric film disposed therebetween and having a first face opposing the first electrode, and at least two temperature characteristic adjustment films formed to oppose the first face of the piezoelectric film with the first electrode interposed therebetween. Moreover, the resonator includes a frame that surrounds at least part of the vibration portion; and a holding arm connecting the vibration portion to the holding portion. The vibration portion includes a surface opposing the first face of the piezoelectric film and having first and second regions in which an average amount of displacement is larger than an average amount of displacement in the first region when the vibration portion vibrates.

Abstract: A bulk-acoustic wave resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; a metal pad connected to the first electrode and the second electrode; and a connection member connected an upper surface of the metal pad. A lower end portion of the connection member includes a tapered portion decreasing in a diameter in a direction toward a lower end of the connection member, and an angle between an inclined surface of the tapered portion and the upper surface of the metal pad is 45° to 80°.

Abstract: A MEMS resonator is operated at its parallel resonance frequency. An acoustic wave is propagated laterally away from a central region of the MEMS resonator through a piezoelectric layer of the MEMS resonator. The propagating acoustic wave is attenuated with concentric confiners that surround and are spaced apart from a perimeter of an electrode that forms the MEMS resonator.

Abstract: An acoustic resonator package includes a substrate, an acoustic resonator disposed on the substrate, the acoustic resonator including a first hydrophobic layer, a cap configured to accommodate the acoustic resonator, a bonding portion configured to bond the substrate to the cap, and a second hydrophobic layer disposed on the substrate at a position between the acoustic resonator and the bonding portion.

Abstract: Acoustic resonator devices, filters, and methods are disclosed. An acoustic resonator includes a substrate and a lithium niobate (LN) plate having front and back surfaces and a thickness ts. The back surface faces the substrate. A portion of the LN plate forms a diaphragm spanning a cavity in the substrate. An interdigital transducer (IDT) is on the front surface of the LN plate with interleaved fingers of the IDT on the diaphragm. The LN plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic wave in the diaphragm. Euler angles of the LN plate are [0°, ?, 0°], where 0???60°. A thickness of the interleaved fingers of the IDT is greater than or equal to 0.8 ts and less than or equal to 2.0 ts.

Abstract: Methods of designing a BAW resonator and filter and the resulting devices are provided. Embodiments include patterning a bottom electrode of a resonator; patterning a top electrode of the resonator; and intersecting areas of the top and bottom electrodes to provide an effective area of the resonator, wherein the effective area includes a closed-loop contour line including a pulse function pattern with pre-defined amplitude, period and a number of repetitions of pulses along the closed-loop contour line.

Abstract: An acoustic resonator includes a substrate, a center portion, an extending portion, and a barrier layer. A first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on the substrate in the central portion. The extending portion is configured to extend from the center portion, and includes an insertion layer disposed below the piezoelectric layer. The barrier layer is disposed between the first electrode and the piezoelectric layer.

Abstract: A zero-output coupled resonator filter (ZO-CRF) and related radio frequency (RF) filter circuit are provided. In examples discussed herein, the ZO-CRF can be configured to function as a shunt resonator(s) in an RF filter circuit (e.g., a ladder filter circuit). The ZO-CRF includes a first resonator and a second resonator that are coupled to each other via a coupling layer. The first resonator and the second resonator receive a first voltage and a second voltage, respectively. The first voltage and the second voltage can be configured in a number of ways to cause the ZO-CRF to resonate at different resonance frequencies. As such, it may be possible to modify resonance frequency of the ZO-CRF in an RF filter circuit based on signal connection. As a result, it may be possible to reduce total inductance of the RF filter circuit, thus helping to reduce footprint of the RF filter circuit.

Abstract: A BAW resonator comprises: a substrate comprising an acoustic reflector; a first electrode disposed over the acoustic reflector, and comprising a first electrode layer comprising a comparatively high acoustic impedance material, and a second electrode layer comprising a comparatively low acoustic impedance; a piezoelectric layer disposed over the second electrode layer; and a second electrode disposed over the piezoelectric layer, and comprising a third electrode layer comprising the low acoustic impedance, and a fourth electrode layer comprising the comparatively high acoustic impedance material and being disposed directly on the piezoelectric layer. A total thickness of an acoustic stack of the BAW resonator is approximately ?/2, where ? is a wavelength corresponding to a thickness extensional resonance frequency of the BAW resonator.

Abstract: A method for creating a double Bragg mirror is provided. The method comprises providing a wafer having a plurality of bulk acoustic wave (BAW) devices at an intermediate stage of manufacturing. A first dielectric layer is deposited over the wafer. A plurality of as-deposited thicknesses of the dielectric layer are determined, each as-deposited thickness corresponding to one BAW device from the plurality of BAW devices. A corresponding trimmed dielectric layer over each of the BAW devices is formed by removing a portion of the dielectric layer over each of the BAW devices, with a thickness of the removed portion determined from a corresponding as-deposited thickness and a target thickness. A Bragg acoustic reflector that includes the corresponding trimmed dielectric layer is formed over each of the BAW devices.

Abstract: Embodiments provide a solidly-mounted bulk acoustic wave (BAW) resonator and method of making same. In embodiments, the BAW resonator may include a planarization portion in an inactive region of the BAW resonator that is coplanar with a piezoelectric layer of the BAW resonator in an active region of the BAW resonator. Other embodiments may be described and claimed.

Abstract: There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a Z-cut piezoelectric plate having parallel 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 (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. A thickness of the interleaved fingers of the IDT is greater than or equal to 0.85 times a thickness of the diaphragm.

Abstract: Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including fluidic systems, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate and a first layer of piezoelectric material. The bulk acoustic wave (BAW) resonator may comprise a top electrode. A sensing region may be acoustically coupled with the top electrode of the bulk acoustic wave (BAW) resonator.

Abstract: Multiplexers are disclosed. A multiplexer can include a first filter and a second filter that are coupled to a common node. The second filter can include a first type of acoustic wave resonators (e.g., bulk acoustic wave resonators) and a series acoustic wave resonator of a second type (e.g., a surface acoustic wave resonator) that is coupled between the acoustic wave resonators of the first type and the common node. The first filter can provide a single-ended radio frequency signal. In certain embodiments, the first filter can be a receive filter and the second filter can be a transmit filter.

Abstract: An acoustic wave filter device is disclosed. The device includes an acoustic wave filter element, and a first resonator and a second resonator coupled to the acoustic wave filter element. The acoustic wave filter element includes interdigited input electrodes and output electrodes located on a top surface of a piezoelectric layer. Each of the first and the second resonators includes a top electrode on the top surface, and a bottom electrode on the bottom surface of the piezoelectric layer. At least one of each of the first and the second resonators' electrodes is electrically connected to the acoustic wave filter element. The first resonator has a first notch in resonator impedance at a first frequency. The second resonator includes a first mass loading layer on the second resonator electrode such that the second resonator has a second notch in resonator impedance at a second frequency different from the first frequency.

Abstract: A device for use in a medium comprising a medium vibro-acoustic impedance. The device includes an elastic material including a plurality of unit cells. The plurality of unit cells includes a first unit cell. The first unit cell includes a first unit-cell joint comprising a first unit-cell joint wall defining a first joint central void, a first unit-cell joint inclusion located in the first joint central void, and at least two first unit-cell arms connected to and extending away from the first unit-cell joint. The elastic material includes an elastic-material vibro-acoustic impedance. The elastic-material vibro-acoustic impedance and the medium vibro-acoustic impedance are sufficiently vibro-acoustically impedance-matched to couple time-varying, propagating vibro-acoustic fields between said elastic material and the medium.

Abstract: An acoustic resonator includes: an upper electrode including a first active region disposed on an upper portion of a piezoelectric layer, and a first extended region extended from the first active region; a lower electrode including a second active region disposed on a lower portion of the piezoelectric layer, and a second extended region extended from the second active region; a first metal layer including a first resistance reduction region disposed on the first extended region; and a second metal layer including a second resistance reduction region disposed on the second extended region. The first metal layer includes a first conductive link region extended from the first resistance reduction region. The second metal layer includes a second conductive link region extended from the second resistance reduction region. The first and second conductive link regions correspond to respective portions of a side boundary of the first and second active regions.

Abstract: A radio-frequency filter (10) includes a series arm circuit (11) and a parallel arm circuit (12). The series arm circuit (11) is disposed on a path connecting an input/output terminal (11m) and an input/output terminal (11n). The parallel arm circuit (12) is connected to a ground and to a node (x1) on the path. The series arm circuit (11) includes a series connecting circuit (11e) and a first variable frequency circuit (11a). The series connecting circuit (11e) includes a series arm resonator (s1) and a capacitor (C1). The first variable frequency circuit (11a) is connected in parallel with the series connecting circuit (11e) and varies the anti-resonant frequency of the series arm circuit (11). The first variable frequency circuit (11a) includes a capacitor (C2) and a switch (SW1) connected in series with each other. The series arm resonator (s1) and the capacitor (C1) are connected in series with each other.

Abstract: A radio-frequency filter (10) includes a series arm resonator (s1) connected between input/output terminals (11m and 11n) and parallel arm circuits (110 and 120) connected to a node (xl) and a ground. The parallel arm circuit (110) includes a parallel arm resonator (p1) and a variable frequency circuit (110A) connected in series with each other between the node (xl) and a ground. The variable frequency circuit (110A) changes the resonant frequency of the parallel arm circuit (110). The variable frequency circuit (110A) is connected in series with the parallel arm resonator (p1) and includes a capacitor (C1) and a switch (SW1) connected in parallel with each other. The parallel arm circuit (120) includes a capacitor (C2) and a switch (SW2) connected in series with each other between the node (x1) and a ground.

Abstract: A bandpass filter includes a capacitor coupled between an input node and an output node, and a dual-resonator structure coupled between the input node, the output node, and ground.

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, the diaphragm having an edge about a perimeter of the cavity. 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 the edge of the diaphragm is at an oblique angle to the fingers and to an X crystalline axis of the piezoelectric plate.

Abstract: There is disclosed acoustic resonators and filter devices. An acoustic resonator 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 (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 interleaved fingers include a first layer having a rectangular shape adjacent the diaphragm and a second layer over the first layer opposite the diaphragm, and wherein a width of the second layer varies along a length of each finger.

Abstract: A bulk acoustic wave resonator includes a substrate; a lower electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the lower electrode; an upper electrode disposed to cover at least a portion of the piezoelectric layer; and a passivation layer disposed to cover at least a portion of the upper electrode, wherein the passivation layer includes a non-trimming-processed portion disposed outside an active region of the bulk acoustic wave resonator in which portions of the lower electrode, the piezoelectric layer, and the upper electrode overlap, and having a thickness that is thicker than a thickness of a portion of the passivation layer disposed in the active region.

Abstract: A pressure sensor apparatus is disclosed. The pressure sensor apparatus includes a bulk acoustic wave (BAW) die having a die interface side and a pressure contact side, a sensor BAW resonator and a reference BAW resonator disposed on the die interface side of the BAW die, a control circuit die coupled to the die interface side of the BAW die via an attachment layer, and an extended opening on the pressure contact side that extends into a depth of the BAW die and is generally aligned with the sensor BAW resonator, the extended opening being configured to translate an external pressure on the pressure contact side onto the sensor BAW resonator.

Abstract: There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a Z-cut piezoelectric plate having parallel 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 (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. A thickness of the interleaved fingers of the IDT is greater than or equal to 0.85 times a thickness of the diaphragm.

Abstract: A focusing interdigital transducer (IDT) and corresponding single- and dual-port piezoelectric devices are disclosed. The focusing interdigital transducer, which generates Lamé acoustic waves, permits operation at significantly higher frequencies than those possible with traditional IDTs. The focusing IDT employs multiple arced fingers formed both above and below the piezoelectric layer to improve coupling efficiency by coupling through both the e31 and e33 piezoelectric coefficients to the piezoelectric layer. By optimizing both anchor design and location, acoustic wave losses are minimized, thereby improving the device's quality factor Q. Through proper bus design and selection of the number of IDT fingers, a device's impedance can be tuned for a given application. The focusing IDTs may be used in single-port filter devices and dual-port transformer devices. The single- and dual-port devices may operate at a single frequency, at two frequencies, or over a band of frequencies.

Abstract: The present disclosure describes a micromechanical resonator comprising a resonator element (40) having a length (l1) and a width (w1) that is perpendicular to the length. The resonator element has a length-to-width aspect ratio in a range of 1.8 to 2.2. The resonator element is suspended to a support structure with two or more anchors (41, 43). Each of the two or more anchors is attached to a first location or a second location. The first location is at a shorter side (42) of the resonator element. The first location divides the width (w1) of the resonator element into a larger portion (w3) and a smaller portion (w2) such that a ratio between said smaller portion (w2) and the whole width (w1) is in a range of 0.10 to 0.28. The second location is at a longer side (44). The second location divides the length (l1) of the resonator element into a larger portion (l3) and a smaller portion (l2) such that a ratio between said smaller portion (l2) and the whole length (l1) is in a range of 0.36 to 0.48.

Abstract: A bulk acoustic wave resonator apparatus includes a resonator member having an annulus shape, and at least one anchor structure coupling the resonator member to a substrate. A perimeter of the resonator member is at least partially defined by respective sidewalls that are slanted at an angle relative to a plane defined by a surface of the resonator member. The surface of the resonator member may be defined by a (100) crystal plane, and the angle of the respective sidewalls may be defined by a (111) crystal plane. Related fabrication methods are also discussed.

Abstract: A bulk acoustic wave filter device includes a substrate including an insulating layer, a resonance portion including a bottom electrode, disposed on the substrate, a piezoelectric layer, disposed above at least a portion of the bottom electrode, and a top electrode disposed above at least a portion of the piezoelectric layer, a wiring portion connected to the resonance portion such that the top electrode or the bottom electrode extends into the wiring portion, a connection electrode connecting the top electrode and the bottom electrode to an external device, and a heat transfer member connecting a portion of at least one of the bottom electrode and the top electrode that is disposed in the wiring portion to the substrate. The resonance portion is provided with a cavity disposed below the bottom electrode, and the heat transfer member is disposed outside of the cavity.

Abstract: There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a Z-cut lithium niobate piezoelectric plate having parallel 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 (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. A thickness of the interleaved fingers of the IDT is greater than or equal to 0.85 times a thickness of the piezoelectric plate.

Abstract: An acoustic wave device includes: a support substrate; a single piezoelectric substrate that is located on the support substrate and is single-crystal; first electrodes located on a first surface of the piezoelectric substrate; second electrodes located on a second surface of the piezoelectric substrate; and an acoustic mirror that is bonded on the support substrate, is located between the support substrate and the first electrodes in resonance regions where the first electrodes and the second electrodes face each other across at least a part of the piezoelectric substrate, is not located between the support substrate and the first electrodes in at least a part of a region between the resonance regions, and reflects an acoustic wave propagating through the piezoelectric substrate.

Abstract: A bulk-acoustic wave resonator includes: a membrane layer disposed on a substrate and forming a cavity; a lower electrode disposed on the membrane layer; a piezoelectric layer disposed on the lower electrode; an upper electrode disposed on the piezoelectric layer, and including a frame part disposed at an edge of an active area and having a thickness greater than that of a portion of the upper electrode disposed in a central portion of the active area; and a frequency adjusting layer disposed on the piezoelectric layer and the upper electrode. The frequency adjusting layer is excluded from an inclined surface of the frame part, or a thickness of a portion of the frequency adjusting layer on the inclined surface is less than that of other portions of the frequency adjusting layer. The frequency adjusting layer is disposed on a portion of the piezoelectric layer protruding from the upper electrode.

Abstract: A method includes the following operations: forming a piezoelectric substrate including a piezoelectric structure and a conductive contact structure, in which the piezoelectric structure has a conductive layer and a piezoelectric layer in contact with the conductive layer, and the conductive contact structure is electrically connected to the piezoelectric structure and protrudes beyond a principal surface of the piezoelectric substrate; forming a semiconductor substrate having a conductive receiving feature and a semiconductor device electrically connected thereto; aligning the conductive contact structure of the piezoelectric substrate with the conductive receiving feature of the semiconductor substrate; and bonding the piezoelectric substrate with the semiconductor substrate such that the conductive contact structure is in contact with the conductive receiving feature.

Abstract: A piezoelectric thin film resonator includes: a substrate; a piezoelectric film located on the substrate; lower and upper electrodes facing each other across the piezoelectric film; a mass load film that is located at least one of a first side, which is closer to the upper electrode, of the piezoelectric film and a second side, which is closer to the lower electrode, of the piezoelectric film, separated from the upper and lower electrodes, and surrounds in plan view a resonance region at least in part, the lower and upper electrodes facing each other across the piezoelectric film in the resonance region; and an acoustic reflection layer that includes the resonance region and the mass load film in plan view, is located in or on the substrate, and includes an air gap or an acoustic mirror in which at least two layers with different acoustic characteristics are stacked.

Abstract: Acoustic resonator devices, filters, and methods are disclosed. An acoustic resonator includes a substrate and a lithium niobate (LN) plate having front and back surfaces. The back surface is attached to a surface of the substrate except for a portion of the LN plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the LN plate such that interleaved fingers of the IDT are disposed on the diaphragm. The LN plate and the IDT are configured such that a radio frequency signal applied to the IDT excites a shear primary acoustic wave in the diaphragm. The Euler angles of the LN plate are [0°, ?, 0° ], where ? is greater than or equal to 0° and less than or equal to 60°.

Abstract: A method for forming a lamb acoustic wave resonator and filter and the resulting device are provided. Embodiments include forming a sacrificial layer over a substrate; forming a first electrode over the sacrificial layer; forming a piezoelectric thin film over the first electrode; forming a second electrode over the piezoelectric thin film; forming a hardmask over the second electrode; etching through the hardmask and the second electrode down to the piezoelectric thin film forming self-aligned vias; forming and patterning a photoresist layer over the self-aligned vias; etching through the photoresist layer forming cavities extending through the vias and to the sacrificial layer; and removing the sacrificial layer forming a cavity gap under the cavities and first metal electrode.

Abstract: A symmetrical MEMS resonator is disclosed with a high quality factor. The MEMS resonator includes a silicon layer with a top surface and bottom surface opposite the top surface. A pair of first metal layers is provided above the top surface of the silicon layer and a corresponding pair of second metal layers is symmetrically provided below the second surface of the silicon layer relative to the pair of first metal layers. Furthermore, a first piezoelectric layer is disposed between the pair of first metal layers and a second piezoelectric layer is disposed between the pair of second metal layers.

Abstract: Acoustic wave filter devices is disclosed. The device includes a piezoelectric layer, an input electrode and an output electrode located on a top surface of the piezoelectric layer and physically separated from one another, and a counter electrode having a top surface connected to a bottom surface of the piezoelectric layer. The input and output electrodes each include a base and at least one extension extending from the base. The at least one extension of the input electrode extending alongside and in a generally opposite direction to and separated by a gap width from an adjacent extension of the at least one extensions of the output electrode. In some embodiments, the at least one extension of the input or output electrodes has a width that can changes from a first end of the at least one extension to a second end.

Abstract: A bulk acoustic wave (BAW) resonator has a bottom electrode, a top electrode over the bottom electrode, and a multilayer piezoelectric structure between the bottom electrode and the top electrode. The multilayer piezoelectric structure has a first piezoelectric layer having a first electromechanical coupling coefficient and a second piezoelectric layer having a second electromechanical coupling coefficient that is different than the first electromechanical coupling coefficient.

Abstract: A radio frequency front-end circuit includes a first filter that is a frequency variable filter connected to a first select terminal of a switching circuit, and a second filter connected to a second select terminal of the switching circuit. The switching circuit includes a first switch that switches over conduction and non-conduction between a common terminal and the second select terminal. The first filter includes a serial arm resonance circuit connected to the first select terminal, a parallel arm resonator, and a frequency varying circuit. The frequency varying circuit includes a capacitor and a third switch connected in parallel to each other, and is connected in series to the parallel arm resonator. The frequency varying circuit shifts a frequency of the first filter depending on conduction and non-conduction of the third switch.

Abstract: A filter includes series units and shunt units. Each series unit includes at least one bulk acoustic wave resonator. Each shunt unit includes at least one bulk acoustic wave resonator and is disposed between one of the series units and a ground. One of the series units or one of the shunt units includes a first bulk acoustic wave resonator, a second bulk acoustic wave resonator, and a third bulk acoustic wave resonator connected in series. The second bulk acoustic wave resonator has a polarity different from a polarity of the first bulk acoustic wave resonator and a polarity of the third bulk acoustic wave resonator.

Abstract: A filter circuit includes: a first element that is a first capacitor or a first inductor connected in series between input and output terminals; a second element that is connected in parallel to the first element between the input and output terminals, is a second inductor when the first element is the first capacitor, and is a second capacitor when the first element is the first inductor; a third element that is connected in parallel to the first element and in series with the second element between the input and output terminals, is a third inductor when the first element is the first capacitor, and is a third capacitor when the first element is the first inductor; and an acoustic wave resonator having a first end coupled to a first node between the second element and the third element and a second end coupled to a ground terminal.

Abstract: Disclosed is a bulk acoustic wave resonator (BAWR). The BAWR includes a bulk acoustic wave resonance unit with a first electrode, a second electrode, and a piezoelectric layer. The piezoelectric layer is disposed between the first electrode and the second electrode. An air edge is formed at a distance from a center of the bulk acoustic wave resonance unit.

Abstract: A method for forming an acoustic resonator comprising: forming a piezoelectric material on a first substrate; and applying the piezoelectric material to a second substrate on which the acoustic resonator is fabricated upon.

Abstract: There is disclosed acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having parallel 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 (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. A thickness of the interleaved fingers of the IDT is greater than or equal to 0.85 times a thickness of the piezoelectric plate.

Abstract: A bulk acoustic wave resonator includes a substrate, a first electrode and a second electrode disposed on the substrate, and a piezoelectric layer disposed between the first electrode and the second electrode. At least one of the first electrode and the second electrode includes an alloy of molybdenum and tantalum.