Abstract: Devices and processes for preparing devices are described for a bulk acoustic wave resonator. A stack formed over a substrate includes a piezoelectric film element, a first (e.g., bottom) electrode coupled to a first side of the piezoelectric film element, and a second (e.g., top) electrode that is coupled to a second side of the piezoelectric film element. A cavity is positioned between the stack and the substrate. The resonator includes one or more planarizing layers, including a first planarizing layer around the cavity, wherein a first portion of the first electrode is adjacent the cavity and a second portion of the first electrode is adjacent the first planarizing layer. The resonator optionally includes an air reflector around the perimeter of the piezoelectric film element. The stack is configured to resonate in response to an electrical signal applied between the first electrode and the second electrode.

Abstract: Provided is an acoustic resonator including: a substrate including a first cavity; a first electrode formed above the substrate; a piezoelectric layer formed on one surface of the first electrode; and a second electrode formed on one surface of the piezoelectric layer, wherein the first electrode and the piezoelectric layer include an overlapping area that corresponds to a first end and a second end of the first cavity, the first electrode has a termination surface formed as an inclined surface of a first acute angle ?1 outside the overlapping area with respect to the second end of the first cavity, the piezoelectric layer is formed to include a first air bridge area that has a second cavity and is formed between the piezoelectric layer and the first electrode in a vertical direction and between the second end of the first cavity and the termination surface in a horizontal direction.

Abstract: Methods of fabricating acoustic devices are disclosed. A lateral etch stop is formed in a substrate. A back surface of a piezoelectric plate is attached to a front surface of the substrate. A conductor pattern is formed on the front surface of the piezoelectric plate, the conductor pattern including interleaved fingers of an interdigital transducer (IDT). A cavity is etched in the substrate using an etchant introduced through one or more openings in the piezoelectric plate. A lateral extent of the cavity is defined by the lateral etch stop. After etching the cavity, a portion of the piezoelectric plate forms a diaphragm spanning the cavity with the interleaved fingers of the IDT disposed on the diaphragm.

Abstract: A sensor device includes a substrate having a substrate surface, a first IDT electrode, a second IDT electrode, and a waveguide. The first IDT electrode and the second IDT electrode are positioned on the substrate surface. The waveguide is positioned on the substrate surface and between the first IDT electrode and the second IDT electrode. At least one of the first IDT electrode and the second IDT electrode includes a reference electrode and a signal electrode each including a plurality of electrode fingers, the plurality of electrode fingers being arranged in a juxtaposed manner in one direction. A distance between the at least one of the first IDT electrode and the second IDT electrode and the waveguide is shorter than an interval between the reference electrode and the signal electrode in the one direction.

Abstract: A method of forming a filter device has a bonding layer formed on a substrate having at least a location for a first cavity and a location for a second cavity on a single die. A piezoelectric plate is bonded to the bonding layer and spans the first and the second cavity. Excess portions of piezoelectric plate are removed that extend a certain length past the perimeter of the first cavity and of the second cavity. Excess portions may be piezoelectric material that extends in the length and width direction past the perimeter of a cavity by more than between 2 and 25 percent of the cavity perimeter. An interdigital transducer (IDT) is on a front surface of the piezoelectric plate and having interleaved fingers over the first cavity.

Abstract: The invention provides a signal isolation and transmission device, comprising a high-frequency amplitude modulation circuit, a signal demodulation circuit, a first H-field antenna and a second H-field antenna. The first H-field antenna and second H-field antenna are both loop antennas with an external conductive shielding layer, and an insulating layer is wrapped outside the conductive shielding layer. The annular parts of the first H-field antenna and second H-field antenna face and abut each other. The high-frequency amplitude modulation circuit is connected with a pin of the first H-field antenna, and a pin of the second H-field antenna is connected with the signal demodulation circuit. The signal to be tested is modulated onto a high-frequency carrier signal by the high-frequency amplitude modulation circuit, and then isolated and transmitted by the two H-field antennas, which greatly improves the anti-interference effect, reduces the attenuation degree and improves the coupling degree of the signals.

Abstract: A bulk acoustic 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 protective layer disposed to cover at least the metal pad.

Abstract: A film bulk acoustic resonator includes: a first electrode disposed on a substrate; a piezoelectric body disposed on the first electrode and including AlN to which a dopant is added; and a second electrode disposed on the piezoelectric body and facing the first electrode such that the piezoelectric body is interposed between the second electrode and the first electrode, wherein the dopant includes either one of 0.1 to 24 at % of Ta and 0.1 to 23 at % of Nb.

Abstract: A resonator that includes a piezoelectric vibrating portion; a retainer provided in at least part of an area surrounding the piezoelectric vibrating portion; a first node generating portion disposed between the piezoelectric vibrating portion and the retainer; a first connecting arm that connects the first node generating portion to a region in the piezoelectric vibrating portion that faces the first node generating portion; and a first retaining arm that connects the first node generating portion to a region in the retainer that faces the first node generating portion. The first node generating portion is substantially symmetrical with respect to each of two lines passing through a center of the first node generating portion along a first direction and a second direction orthogonal to the first direction, with the first direction being a direction that the first connecting arm connects the first node generating portion to the piezoelectric vibrating portion.

Abstract: A crystal vibration element that includes a crystal piece that has a prescribed crystal orientation, and a first direction and a second direction in a plan view thereof; and excitation electrodes that are respectively provided on front and rear surfaces of the crystal piece in order to excite a thickness shear vibration in the crystal piece upon application of an alternating electric field. A vibration distribution of the crystal piece has a vibration region that extends in a band-like shape in the second direction of the crystal piece and non-vibration regions that are adjacent to opposed sides of the vibration region in the first direction of the crystal piece.

Abstract: Embodiments include a real time etch rate sensor and methods of for using a real time etch rate sensor. In an embodiment, the real time etch rate sensor includes a resonant system and a conductive housing. The resonant system may include a resonating body, a first electrode formed over a first surface of the resonating body, a second electrode formed over a second surface of the resonating body, and a sacrificial layer formed over the first electrode. In an embodiment, at least a portion of the first electrode is not covered by the sacrificial layer. In an embodiment, the conductive housing may secure the resonant system. Additionally, the conductive housing contacts the first electrode, and at least a portion of an interior edge of the conductive housing may be spaced away from the sacrificial layer.

Abstract: According to one embodiment, a transducer includes a first electrode, a second electrode, a third electrode, a first piezoelectric portion, and a second piezoelectric portion. A resistor and an inductor are connected to the second electrode. The first piezoelectric portion is provided between the first electrode and the third electrode. The second piezoelectric portion is provided between the second electrode and the third electrode. A ratio of the absolute value of a difference between a first resonant frequency and a second resonant frequency to the first resonant frequency is 0.29 or less. The first resonant frequency is mechanical. The first resonant frequency is of the first piezoelectric portion and the second piezoelectric portion. The second resonant frequency is of a parallel resonant circuit. The parallel resonant circuit includes an electrostatic capacitance, the inductor, and the resistor. The electrostatic capacitance is between the second electrode and the third electrode.

Abstract: A magnetic transmitting antenna has a beam member having a first end and a second end, wherein the beam member comprising: an elastic member; at least one magnetoelastic member disposed on a first surface of the elastic member; and an actuator disposed on a second surface of the elastic member, wherein the actuator is configured to apply stress to the elastic member thereby applying a bending stress thereto for changing the magnetic permeability of the at least one magnetoelastic member, which in turn, changes an external magnetic field. At least one magnet is disposed adjacent to the magnetoelastic member such that magnetization is induced in the magnetoelastic member.

Abstract: A speaker includes: a vibration plate, a piezoelectric member on a surface of the vibration plate, and a first adhesive member between the vibration plate and the piezoelectric member, wherein: the piezoelectric member is a unimorph piezoelectric member, and the first adhesive member has a high elastic modulus, or the piezoelectric member is a bimorph piezoelectric member, and the first adhesive member has a low elastic modulus.

Abstract: A gas sensor may include a plurality of elements that are responsive to particular gases based at least in part on the temperature of the temperature sensitive element. A first of the elements may be a gas detection element heated to a temperature at which it is responsive to a gas of interest. A plurality of additional elements may be configured in a reference element network and heated to a temperature at which they are not responsive to the gas of interest but are instead responsive to other effects such as humidity. The reference element network output may be used to remove the other effects (e.g., humidity) from the gas detection element output.

Abstract: A crystal oscillator includes: a crystal resonator plate having a first excitation electrode and a second excitation electrode. A first sealing member covers the first excitation electrode of the crystal resonator plate. A second sealing member covers the second excitation electrode of the crystal resonator plate. An internal space is formed by bonding the first sealing member to the crystal resonator plate and the second sealing member to the crystal resonator plate, and seals a vibrating part of the crystal resonator plate. First and second shield electrodes are connected to a fixed potential (e.g. GND potential) in the internal space.

Abstract: A crystal resonator (101) includes: a piezoelectric resonator plate (2) on which a first excitation electrode and a second excitation electrode are formed; a first sealing member (3) that covers the first excitation electrode of the piezoelectric resonator plate (2); and a second sealing member (4) that covers the second excitation electrode of the piezoelectric resonator plate (2). The first sealing member (3) is bonded to the piezoelectric resonator plate (2) while the second sealing member (4) is bonded to the piezoelectric resonator plate (2) so that an internal space (13), which hermetically seals a vibrating part including the first excitation electrode and the second excitation electrode of the piezoelectric resonator plate (2), is formed. Plating films (51, 52) are formed respectively on both the first sealing member (3) and the second sealing member (4), on respective surfaces opposite to surfaces to be bonded to the piezoelectric resonator plate (2).

Abstract: A piezoelectric component of the present disclosure includes: a substrate having a rectangular plate shape having a longitudinal direction and a width direction; a pair of electrodes disposed on a first surface of the substrate so as to leave space therebetween which is located in a central region in the longitudinal direction of the substrate; and a piezoelectric element both ends of which are fixed to the pair of electrodes, respectively, the pair of electrodes each including a notch extending from a central region side and in the longitudinal direction of the substrate.

Abstract: A coupled resonator filter includes a first resonator, a second resonator, one or more intervening layers, a first border ring, and a second border ring. The first resonator includes a first piezoelectric layer and a first electrode in contact with the first piezoelectric layer. The second resonator includes a second piezoelectric layer and a second electrode in contact with the second piezoelectric layer. The one or more intervening layers are between the first resonator and the second resonator and acoustically couple the first resonator and the second resonator. The first border ring is on the first electrode. The second border ring is on the second electrode. By providing both the first border ring and the second border ring, spurious modes in the coupled resonator filter may be suppressed, thereby improving the performance thereof.

Abstract: Bulk acoustic wave (BAW) resonators, and particularly shaped border (BO) rings for BAW resonators are disclosed. Top electrode arrangements are disclosed that include a BO ring arranged about a periphery of a top electrode, where the BO ring forms a top surface having a shape that is sloped or graded in comparison to planar surfaces of the top electrode. The top surface of the BO ring may be arranged such that a height of the top surface is graded in a descending manner toward a central region of the BAW resonator. BAW resonators as disclosed herein are provided with high quality factors and suppression of spurious modes while also providing reduced acoustic leakage and mode conversion.

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: The present disclosure relates to a vibration generation device, a display apparatus including the vibration generation device, and a vehicle including the vibration generation device. A vibration generation device includes a piezoelectric ceramic part having a certain interval, a piezoelectric material layer between the piezoelectric ceramic parts, and an electrode part configured to provide electric field to one or more of the piezoelectric ceramic part and the piezoelectric material layer.

Abstract: A crystal vibration element that includes a crystal piece that has a prescribed crystal orientation, and a first direction and a second direction in a plan view thereof; and excitation electrodes that are respectively provided on front and rear surfaces of the crystal piece in order to excite a thickness shear vibration in the crystal piece upon application of an alternating electric field. A vibration distribution of the crystal piece has a vibration region that extends in a band-like shape in the second direction of the crystal piece and non-vibration regions that are adjacent to opposed sides of the vibration region in the first direction of the crystal piece.

Abstract: A liquid discharge apparatus includes a head configured to discharge a liquid, a liquid receptacle configured to receive the liquid discharged from the head, a moving device configured to move the liquid receptacle relative to the head, and control circuitry. The liquid receptacle includes an absorber and an absorber case configured to house the absorber. The absorber includes a slit. The control circuitry is configured to cause the head to discharge the liquid into the slit of the absorber while moving, with the moving device, the liquid receptacle with respect to the head.

Abstract: The structure of a frequency synthesizer for acoustic waves includes an input narrow band transducer in its input arm for receiving an input electric signal at an input frequency, a wide band transducer in its output arm for supplying an output signal; and a perforated region formed of a two dimensional array of cavities disposed between the first and second arms. The first arm contains multiple metal fingers, disposed perpendicular to the first arm and spaced apart from one another at a distance of the wavelength of the input signal to ensure acoustic excitation in the first arm at the input frequency. The second arm contains a single finger to accommodate a non-linear output signal oscillating at a harmonic of the first frequency. The frequency synthesizer can be patterned in aluminum nitride (AlN) in a silicon substrate.

Abstract: A system includes a pressure sensor combined with a MEMS microphone. The pressure sensor and the MEMS microphone arranged side by side are formed on a same substrate.

Abstract: An acoustic resonator includes a resonant portion including a piezoelectric layer disposed between a first electrode and a second electrode, and a frame portion disposed along an outer edge of the second electrode. The frame portion includes three reflective portions reflecting lateral waves generated in the resonant portion.

Abstract: A crystal unit includes an AT-cut crystal element that has a planar shape in a rectangular shape and a part as a thick portion. The crystal element includes a first end portion, a first depressed portion, the thick portion, a second depressed portion, and a second end portion in an order from a side of one short side in viewing a cross section taken along a longitudinal direction near a center of the short side. The first depressed portion is a depressed portion disposed from the thick portion toward the first end portion side, depressed with a predetermined angle ?a and subsequently bulged, and connected to the first end portion. The second depressed portion is a depressed portion disposed from the thick portion toward the second end portion side, depressed with a predetermined angle ?b and subsequently bulged, and connected to the second end portion.

Abstract: A resonator includes a prong of which the width between edges is close to ?/2. The pressure variation at one edge is then in phase opposition with that at the other edge. Acoustic coupling with an incident wave having the wavelength is thus improved. The ratio between the width between edges and the height of the prong is chosen so that only the fundamental mode with bending oscillation of the prong is present. It to prongs of a tuning fork embedded in a solid shared base optimized to contain the energy in the tuning fork while avoiding energy losses in the support. Finally, the tuning fork is advantageously combined with a unit for containing acoustic energy including a rigid reflecting screen.

Abstract: An acoustic resonator structure comprises: a substrate comprising a cavity having a plurality of sides; a first electrode disposed over the cavity; a first connection portion that connects to the first electrode over only one side of the plurality of sides of the cavity; a piezoelectric layer disposed over at least a portion of the first electrode; a second electrode disposed over the piezoelectric layer; and a second connection portion that connects to the second electrode over only the one side of the plurality of sides. The second connection portion does not overlap the first connection portion, and a contacting overlap of the first electrode, the piezoelectric layer and the second electrode provides an active area of the acoustic resonator.

Abstract: A crystal blank includes a pair of tableland-shaped first mesa parts projecting from a flat plate and a pair of tableland-shaped second mesa parts projecting from the pair of first mesa parts. The flat plate's length in a long direction is less than 1000 ?m. The first mesa part is on an inner side of the flat plate's major surface. The second mesa part is on the first mesa part's inner side of an upper surface's outer edge at two ends of the long direction and has a width equivalent to the first mesa part's upper surface at two sides of a short direction. An excitation electrode reaches the second mesa part's outer edge of the upper surface, is located on the inner side of the first mesa part, and on the second mesa part's inner side of the upper surface's outer edge at two sides of the short direction.

Abstract: In a module for detecting a fingerprint, an electronic device using the module and a method for manufacturing an acoustic control member for the module, the module includes a contact member, a transducer, an impedance matching member, an acoustic control member and a signal processor. A fingerprint makes contact with the contact member. The transducer outputs an ultrasonic signal to the contact member and receives the ultrasonic signal reflected from the contact member. The impedance matching member is charged between the contact member and the transducer, to transmit the ultrasonic signal between the contact member and the transducer. The acoustic control member is inserted between the contact member and the transducer. The impedance matching member is charged inside of the acoustic control member. The signal processor makes electric contact with the transducer, to sense the fingerprint based on the received ultrasonic signal.

Abstract: A CMOS compatible GHz ultrasonic pulse/echo transmit-receive ultrasonic delay element demonstrating less than <6 ppm stability over time and having a zero-temperature coefficient of delay at two temperatures. The delay element includes one or more CMOS compatible piezoelectric transducers requiring no release step, which transmit and/or receive a GHz-ultrasonic wave packet. The bulk substrate exhibits low loss for the GHz-ultrasonic wave packet transmitted through the substrate and uses the phenomenon of diffraction to retrieve multiple reflections.

Abstract: A bulk acoustic resonator includes: a substrate including an upper surface on which a substrate protection layer is disposed; and a membrane layer forming a cavity together with the substrate, wherein a thickness deviation of either one or both of the substrate protection layer and the membrane layer is 170 ? or less.

Abstract: According to one embodiment, a sensor adhesion state determination system includes a plurality of sensors, a calculator, and a determiner. Each of the plurality of sensors detects elastic waves. The calculator calculates peak frequencies of the elastic waves on the basis of the elastic waves detected by the plurality of sensors. The determiner determines the adhesion state of each of the sensors by comparing the peak frequencies with information serving as a determination reference.

Abstract: A method for manufacturing a semiconductor apparatus includes: on a base substrate, forming an isolation trench layer, a first dielectric layer, a lower electrode layer and a second dielectric layer; forming a piezoelectric film and an upper electrode layer in an opening in the second dielectric layer; forming a third dielectric layer; forming a first cavity in the third dielectric layer to expose at least part of the upper electrode layer; bonding a first assistant substrate to seal the first cavity; removing a part of the base substrate to expose the isolation trench layer; forming a fourth dielectric layer on a side of the isolation trench; and etching through the fourth dielectric layer, the isolation trench layer, the first dielectric layer to form a second cavity beneath the lower electrode layer, plan views of the first and second cavities providing an overlapped region having a polygon shape without parallel sides.

Abstract: A bulk acoustic wave filter device includes a substrate, a lower electrode on the substrate, a piezoelectric layer covering at least a portion of the lower electrode, and an upper electrode covering at least a portion of the piezoelectric layer. The upper electrode has a density reduction layer disposed on at least a portion thereof, except a central portion of a resonance region of the bulk acoustic wave filter device that deforms and vibrates with the piezoelectric layer during activation of the piezoelectric layer. The density reduction layer has a density lower than a density of other portions of the upper electrode.

Abstract: An FBAR filter device comprising an array of resonators, each resonator comprising a single crystal piezoelectric layer sandwiched between a first and a second metal electrode, wherein the first electrode is supported by a support membrane over an air cavity, the air cavity being embedded in a silicon dioxide layer over a silicon handle, with through-silicon via holes through the silicon handle and into the air cavity, the side walls of said air cavity in the silicon dioxide layer being defined by barriers of a material that is resistant to silicon oxide etchants, and wherein the interface between the support membrane and the first electrode is smooth and flat.

Abstract: A crystal vibrator includes an AT-cut crystal substrate with a vibration portion having a principal surface and a peripheral portion surrounding and thinner than the vibration portion. An excitation electrode is formed on the principal surface and an extension electrode is electrically connected to the excitation electrode. The vibration portion has a first short-edge side lateral surface that abuts the peripheral portion at an acute angle and a tapered lateral surface adjacent to the first short-edge side lateral surface and inclined with respect to the X axis in the XZ? plane. The tapered lateral surface abuts the peripheral portion at an angle that is greater than the angle defined by the first short-edge side lateral surface. The extension electrode extends from the excitation electrode through the tapered lateral surface to a first short-edge side in a longitudinal direction parallel to the Z? axis.

Abstract: A hybrid generator using a thermoelectric generation and a piezoelectric generation are provided. The hybrid generator includes first and second insulating layers spaced apart from each other; a thermoelectric structure disposed between the first and second insulating layers; a first electrode disposed on the second insulating layer; a piezoelectric structure disposed on the first electrode; a third insulating layer disposed on the piezoelectric structure; and a second electrode disposed on the third insulating layer.

Abstract: An ultrasonic device includes a substrate and a support member. The substrate has an element array including a plurality of ultrasonic transducer elements arranged in an array form. The support member has a surface adhered to the substrate in an area including the element array, and an opposite surface opposite from the surface adhered to the substrate, a distance from the surface adhered to the substrate to the opposite surface being different with respect to two adjacent ones of the ultrasonic transducer elements in the element array.

Abstract: A device and method are provided for detecting analyte with correction for the effects of humidity. The device comprises a resonant sensor having an oscillating portion. A capacitor is positioned on the oscillating portion. The capacitor is formed by at least two electrodes and a sensing material positioned between the electrodes. A readout circuit is arranged to measure a response of the oscillating portion (e.g., frequency shift or change in resonance frequency, stiffness or strain) and a capacitance of the capacitor when substances are adsorbed or absorbed in the sensing material. This combination of measurements enables the device to distinguish between various types of adsorbed or absorbed molecules, especially distinguishing between an analyte of interest and water molecules that might interfere with the detection of the analyte.

Abstract: Devices and methods described herein provide electrode pair access from a single side of a device by using one or more via holes through the device. The via hole can pass through or near the center of the device. By creating a conductive path through the via hole of the device, devices and methods of the present disclosure advantageously provide access to a pair of electrodes, each of which contacts a different side of a device layer, on a single side of the device while enabling a greater active device area than is possible using conventional techniques. In addition, the central location of the via hole provides favorable mechanical properties by avoiding radial constriction of the device layers in applications such as piezoelectric devices.

Abstract: A piezoelectric thin film resonator includes: lower and upper electrodes located on a substrate and facing each other; a piezoelectric film sandwiched between the lower and upper electrodes and including lower and upper piezoelectric films, an outer outline of the upper piezoelectric film coinciding with or being located further out than an outer outline of a resonance region in a region surrounding the resonance region, the outer outline of the upper piezoelectric film being located further in than an outer outline of the lower piezoelectric film in the region; an insertion film interposed between the lower and upper piezoelectric films, located in an outer peripheral region within the resonance region, not located in a central region of the resonance region, and located on an upper surface of the lower piezoelectric film in the region; and a protective film located on the upper electrode in the resonance region, and located so as to cover an end face of the upper piezoelectric film and an upper surface of t

Abstract: An image reading device includes a light applying unit that applies light from a light source to a recording medium, a detecting unit that detects the light reflected by the recording medium, a holding member that is movable in a first scanning direction of the light applying unit and holds a calibration member to which the light from the light applying unit is applied, a shaft member that extends in the first scanning direction through the holding member and guides the movement of the holding member in the first scanning direction, and a restricting member that extends in the first scanning direction and restricts rotation of the holding member about the shaft member.

Abstract: A resonator is formed from a unitary slab of a plate of quartz material which is KT cut with a theta cut angle between 20 and 35 degree, the unitary slab of a plate of quartz material having vertical side walls defining (i) an elongated central portion, the elongated central portion having a centerline along its major dimension, the elongated central portion resonating, in use, in an extensional mode disposed at a right angle to said centerline, (ii) a pair of isolating springs integrally connected to said central portion at the centerline thereof and (iii) first and second pairs of tethers, each one of the pairs tethers being integrally connected at a mid point of each the first and second pairs of tethers to ends of the isolating springs remote from the elongated central portion, each of the pairs tethers having two arms which wrap around the elongated central portion so that an end of one arm of the one of the tether approaches, but does not contact, an end of an arm of the another one of the tethers.

Abstract: A bulk acoustic wave (BAW) resonator device includes a bottom electrode on a substrate over one of a cavity and an acoustic mirror, a piezoelectric layer on the bottom electrode, a top electrode on the piezoelectric layer, and a temperature compensation feature having positive temperature coefficient for offsetting at least a portion of a negative temperature coefficient of the piezoelectric layer. At least one of the bottom electrode and the top electrode includes an integrated lateral feature configured to create at least one of a cut-off frequency mismatch and an acoustic impedance mismatch.

Abstract: The present disclosure provides a method of fabricating an ultrasound transducer. A substrate having a first side and a second side opposite the first side is provided. A bottom electrode is formed over the first side of the substrate. A piezoelectric element is formed over the bottom electrode. The piezoelectric element has a chamfered sidewall. A top electrode is formed over the piezoelectric element. A step metal element is formed over a portion of the top electrode proximate to the chamfered sidewall of the piezoelectric element.

Abstract: A piezoelectric oscillator, and method of making the same, includes an oscillation substrate comprising an oscillating part and a surrounding part, wherein the surrounding part is thinner than the oscillating part, and oscillating electrodes disposed on an upper surface and a lower surface of the oscillating part. The oscillation substrate is configured according to H=400.59×S+1.75±1.5, wherein H=100×(T2/T1) and S=T2/(L1?L2), wherein L1 represents an entire length of the oscillation substrate, L2 represents a length of the oscillating part, T1 represents a thickness of the oscillating part, and T2 represents a step height between the oscillating part and the surrounding part.

Abstract: In order to pass a signal having a wide pass bandwidth with respect to a center frequency of a pass band, a surface acoustic wave device includes a first surface acoustic wave element provided with a first pass band; and a second surface acoustic wave element having a second pass band in a high frequency band compared with the first pass band of the first surface acoustic wave element, in which the first surface acoustic wave element and the second surface acoustic wave element have a common input terminal and a common output terminal, and a frequency of a high frequency side of the first pass band of the first surface acoustic wave element is partially overlapped with a frequency of a low frequency side of the second pass band of the second surface acoustic wave element.