Abstract: Acoustic wave devices and methods of fabricating acoustic wave devices. A device includes a piezoelectric substrate and a conductor pattern formed on a surface of the piezoelectric substrate. The conductor pattern includes an interdigitated transducer (IDT) of a surface acoustic wave (SAW) resonator. The conductor pattern includes a substantially beryllium layer proximate the surface of the piezoelectric substrate.

Abstract: A piezoelectric element includes: a piezoelectric body; and a vibrating plate including single crystal silicon having anisotropy having orientation with a relatively high Poisson's ratio and orientation with a relatively low Poisson's ratio (hereinafter, referred to as “low Poisson's ratio orientation”) as a vibrating material, in which the piezoelectric body and the vibrating plate are laminated on each other so that the low Poisson's ratio orientation is in a direction along a high expansion and contraction direction among a direction where a degree of expansion and contraction caused according to a support structure of the piezoelectric body is relatively high (hereinafter, referred to as “high expansion and contraction direction”) and a direction where a degree thereof is relatively low.

Abstract: In an IDT electrode of an acoustic wave element which includes first electrode fingers and second electrode fingers connected to potentials which are different from each other and arranged spaced apart from each other, the first electrode fingers includes first tip parts, and either of the first electrode fingers and the second electrode fingers includes, at a tip area extending along a direction of propagation of an acoustic wave and overlapping with the first tip parts, increase sections in which electrode volumes per unit lengths in a direction of extension of the first electrode fingers and the second electrode fingers are larger in comparison with that of the center area in which the electrode fingers intersect.

Abstract: Illustrative embodiments significantly improve RF isolation in a packaged integrated circuit by separating the pins/pads associated with multiple RF channels from one another and also from pins/pads associated with digital circuits. Specifically, in certain exemplary embodiments, the integrated circuit is configured with the pins/pad for the digital circuits on a first edge of the chip, the pins/pads for common RF signals on a second edge of the chip opposite the first edge, and the pins/pads for the individual RF channels on third and fourth edges of the chip. The pins/pads associated with each RF channel may include multiple pins/pads (an “RF group”) and may have a central RF pin/pad with a ground pin/pad on each side of the central RF pin/pad. One or more ground pins/pads may be placed between adjacent RF groups on a given edge of the chip.

Abstract: A multiplexer includes: a filter located on a surface of a substrate and including first series and parallel resonators and a first wiring line; and another filter located on another surface of another substrate and including second series and parallel resonators and a second wiring line, each of first resonators among the second series and parallel resonators overlapping with the first series and parallel resonators, and/or the first wiring line, each of second resonators other than the first resonators among the second series and parallel resonators overlapping with none of the first series and parallel resonators and the first wiring line, when capacitances of series and parallel resonators in first basic sections including the first resonators are represented by Cs1 and Cp1, and capacitances of series and parallel resonators in second basic sections not including the first resonators are represented by Cs2 and Cp1, Cp1/Cs1 being less than Cp2/Cs2.

Abstract: An elastic wave device includes a first piezoelectric substrate made of LiNbO3, a first band-pass filter provided on the first piezoelectric substrate and including first IDT electrodes, a dielectric layer provided on the first piezoelectric substrate and covering the plurality of first IDT electrodes, a second piezoelectric substrate, a second band-pass filter provided on the second piezoelectric substrate, including second IDT electrodes, and differing from the first band-pass filter in pass band, and a band elimination filter connected to the first band-pass filter. The band elimination filter is provided on a piezoelectric substrate other than the first piezoelectric substrate.

Abstract: An acoustic wave filter device includes a first band pass filter including a first acoustic wave resonator connected between an antenna terminal and a first signal terminal and having a first pass band, and a second band pass filter connected with the antenna terminal and having a second pass band on a higher side of the first pass band. The first acoustic wave resonator includes a substrate on a surface of which a piezoelectric thin film is provided, an IDT electrode provided on the substrate, and reflectors. At least a pitch of some electrode fingers is different from a pitch of other electrode fingers in at least one of the IDT electrode and the reflectors of the first acoustic wave resonator on a side closest to the antenna terminal.

Abstract: An elastic wave filter apparatus includes a transmission-side filter, a reception-side filter, an antenna terminal, and a matching circuit. The matching circuit is connected between a common node of the transmission-side filter and the reception-side filter and the antenna terminal. The transmission-side filter includes a ladder circuit and filter inductors. The matching circuit includes a matching inductor. The ladder circuit includes series arm resonators and parallel arm resonators. The matching inductor is connected between a transmission line connecting the common node and the antenna terminal and a first terminal of the filter inductor on the side of the parallel arm resonator.

Abstract: A filter includes a series-arm resonator connected on a path connecting input/output terminals, and first and second parallel-arm resonators that are connected between the same node on the path and ground. A resonant frequency of the second parallel-arm resonator is higher than a resonant frequency of the first parallel-arm resonator, and an anti-resonant frequency of the second parallel-arm resonator is higher than an anti-resonant frequency of the first parallel-arm resonator. Each of the first and second parallel-arm resonators is defined by an acoustic wave resonator including an IDT electrode. The IDT electrode in the second parallel-arm resonator has a lower aspect ratio than the IDT electrode in the first parallel-arm resonator, where the aspect ratio is a ratio of an overlap width of electrode fingers to the number of pairs of electrode fingers.

Abstract: A hybrid multiplexer includes a filter configured to allow a high-frequency signal of an HB to pass therethrough, and a filter configured to allow a high-frequency signal of an MB to pass therethrough, in which the filter includes a matching circuit, a first resonance circuit defined by one of an LPF and an HPF, and a second resonance circuit defined by the other of the LPF and the HPF, the LPF includes an inductor and a parallel arm resonator, the HPF includes a serial arm resonator and an inductor, and a resonant frequency of the parallel arm resonator and an anti-resonant frequency of the serial arm resonator are both located between a frequency at a low-band end of the HB and a frequency at a high-band end of the HB.

Abstract: An elastic wave device includes a supporting substrate, an acoustic reflection layer disposed on the supporting substrate, a piezoelectric layer disposed on the acoustic reflection layer, and an interdigital transducer electrode disposed on the piezoelectric layer. The acoustic reflection layer includes three or more low acoustic impedance layers and two or more high acoustic impedance layers. A film thickness of the low acoustic impedance layer closest to the piezoelectric layer is larger than a film thickness of the low acoustic impedance layer closest to the low acoustic impedance layer that is closest to the piezoelectric layer.

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 and an counter-electrode on the bottom surface of the piezoelectric layer. Each of the first and the second resonators includes a resonator electrode on the top surface of the piezoelectric layer and a 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 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 that is different from the first frequency.

Abstract: A radio-frequency filter (10) includes a series arm circuit (11) and a parallel arm circuit (12). The series arm circuit (11) includes a series arm resonator (s1a) and a variable frequency circuit (11b) connected in parallel with the series arm resonator (s1a). The variable frequency circuit (11b) includes a series arm resonator (s1b) and a switch (SWb) connected in series with the series arm resonator (s1b). The variable frequency circuit (11b) is configured to change at least one of a resonant frequency that provides a pass band of the radio-frequency filter (10) and an anti-resonant frequency that provides an attenuation pole of the radio-frequency filter (10). A resonant frequency of the series arm resonator (s1b) is different from a resonant frequency of the series arm resonator (s1a).

Abstract: A switching circuit is provided. The switching circuit includes at least one Surface Acoustic Wave (SAW) filter, a Single-Pole n Throw (SPnT) switch connected to an input port of each of the at least one SAW filter, and a Dual-Pole n Throw (DPnT) switch connected to an output port of each of the at least one SAW filter.

Abstract: An acoustic wave device that includes a spinel layer, a piezoelectric layer, a temperature compensating layer between the spinel layer and the piezoelectric layer and an interdigital transducer electrode on the piezoelectric layer is disclosed. The piezoelectric layer is disposed between the interdigital transducer electrode and the spinel layer. The acoustic wave device is configured to generate an acoustic wave having a wavelength of ?. The piezoelectric layer can have a thickness that is less than ?. In some embodiments, the spinel layer can be a polycrystalline spinel layer.

Abstract: A high-frequency module that performs filtering of signals transmitted and received through an antenna includes an antenna terminal, a transmission terminal, a reception terminal, a reception filter connected between the antenna terminal and the reception terminal, a transmission filter connected between the antenna terminal and the transmission terminal, a first element connected between the antenna terminal and the transmission filter, and a second element connected in series between the transmission terminal and the transmission filter. The first element and the second element are capacitively coupled to each other.

Abstract: A multiplexer includes a first filter disposed on a first signal path, a second filter disposed on a second signal path different from the first signal path, the second filter having a passband different from that of the first filter, a common connection point at which the first signal path and the second signal path are connected to each other, and an inductor disposed in series on a path connecting the common connection point and the first filter, the path being a portion of the first signal path. On the first signal path, a distance connecting the common connection point and the inductor is shorter than a distance connecting the inductor and the first filter.

Abstract: A filter device includes a first ladder filter including serial resonators disposed in a terminal-to-terminal path and parallel resonators disposed in connection paths, a first acoustic wave resonator disposed in parallel to the parallel resonator, and a second acoustic wave resonator disposed in parallel to the serial resonator. Resonance points and anti-resonance points of the first and second acoustic wave resonators are both positioned on the lower frequency side or the higher frequency side of a pass band of the first ladder filter, and on the same side of the pass band of the first ladder filter, when viewed from the pass band of the first filter.

Abstract: An acoustic wave filter device includes a first resonant circuit, a second resonant circuit, a first interconnect line, and a second interconnect line. The second resonant circuit includes a second parallel-arm resonator, and a frequency-tuning circuit that allows tuning of the resonant frequency of the second parallel-arm resonator. The frequency-tuning circuit includes a capacitor, and a switching element connected in parallel with the capacitor. The first interconnect line is an interconnect line connected to the portion of the series-arm resonator located adjacent to the first input/output terminal. The second interconnect line is an interconnect line connecting the parallel-arm resonator with the switching element, or an interconnect line connecting the parallel-arm resonator with the capacitor. A first transmission line formed by the first interconnect line, and a second transmission line formed by the second interconnect line are magnetically coupled with each other.

Abstract: Even when frequency characteristics are changed in association with multiple communication bands, an attenuation required for a specific frequency band outside a pass band is obtained. A multiplexer includes a transmission filter, a reception filter, and a common connection point. An antenna-side end of the transmission filter and an antenna-side end of the reception filter are connected to the common connection point. The transmission filter includes multiple resonators including a parallel-arm resonator and a variable capacitor that is connected in series with the parallel-arm resonator. An inductor for forming an attenuation pole is provided between the antenna-side end of the reception filter and the common connection point. By the inductor for forming an attenuation pole and the reception filter, which is capacitive, an attenuation pole at a frequency close to or equal to a specific frequency outside the pass band of a transmission signal is formed.

Abstract: Systems and methods relating to improving transmit (TX) port to receive (RX) port isolation of a duplexer or multiplexer are disclosed. In some embodiments, a system includes a duplexer or multiplexer having a transmit port, a receive port, and an antenna port. The system further includes a leakage cancellation subsystem adapted to cancel a leakage signal from the TX port of the duplexer or multiplexer to the RX port of the duplexer or multiplexer across a desired cancellation bandwidth. The leakage cancellation subsystem compensates for variation of the leakage signal across the desired cancellation bandwidth, thereby improving TX port to RX port isolation over conventional systems.

Abstract: An antenna stack includes a glass cover having an outer face, an inside face opposite the outer face, and a body therebetween. The glass cover additionally has a cavity formed therein, extending into the body from the inside face. The antenna stack further includes an antenna patch positioned within the cavity, and a waveguide layer. The waveguide layer includes polycrystalline ceramic underlying the glass cover. Conductive vias extend through the polycrystalline ceramic and partition the waveguide layer to form feed channels through the polycrystalline ceramic, and major surfaces of the polycrystalline ceramic are overlaid with a conductor having openings that open to the feed channels. The antenna patch is spaced apart from the waveguide layer to facilitate evanescent wave coupling between the feed channels and the antenna patch.

Abstract: A transmission filter in a high frequency module includes serial arm resonators electrically connected in series to a serial arm electrically connecting a shared terminal and a transmission terminal, parallel arm resonators each electrically connected in series to each of parallel arms electrically connecting the serial arm and a ground, a first inductor electrically connected between the ground and a connection end electrically connecting at least the two parallel arm resonators of the parallel arm resonators, and a second inductor electrically connected between the ground and one parallel arm resonator different from the at least two parallel arm resonators of the parallel arm resonators. The second inductor is electromagnetic field coupled to at least one of an antenna side matching element, a transmission side matching element, and a portion of the serial arm in the transmission filter. The first and second inductors obstruct electromagnetic field coupling therebetween.

Abstract: A SAW device includes a SAW element, a conductor connected to the SAW element, an LT substrate including the SAW element, and a case for housing the LT substrate including the SAW element. The case includes a cover part, a lateral part, and a bottom part. The bottom part is including a sapphire substrate, the LT substrate is positioned on a first surface of the sapphire substrate, the first surface serving as an inner surface of the case, and a second surface opposite to the first surface serves as an outer surface of the case. The conductor includes a via conductor provided in a through-hole continuously penetrating through the sapphire substrate and the LT substrate.

Abstract: A radio frequency module includes an elastic wave filter and a low-noise amplifier that amplifies an RF signal output from the elastic wave filter. An output impedance of the elastic wave filter is positioned, on a Smith chart, closer to a noise matching impedance than to a gain matching impedance, at a frequency of at least one of a low frequency end and a high frequency end of a passband of the elastic wave filter. The noise matching impedance indicates the output impedance where a noise figure of the LNA becomes minimum. The gain matching impedance indicates the output impedance where a gain of the LNA becomes maximum.

Abstract: A bandpass acoustic wave filter device includes an IDT electrode and a dielectric film disposed on a piezoelectric substrate including a LiNbO3 layer, and an acoustic wave resonator is defined by the IDT electrode. The acoustic wave resonator utilizes the Rayleigh wave, and a response of an SH wave excited by the acoustic wave resonator is outside a pass band of the acoustic wave filter device.

Abstract: An acoustic wave device includes: a substrate; an acoustic reflection layer located in or on the substrate and including an air gap, or an acoustic mirror; a piezoelectric film located on the acoustic reflection layer; lower and upper electrodes located on the acoustic reflection layer so as to sandwich the piezoelectric film so that resonance regions are located within the acoustic reflection layer and share the acoustic reflection layer, one of the lower and upper electrodes being divided, another one of the lower and upper electrodes being not divided, the lower and upper electrodes facing each other across the piezoelectric film in each of the resonance regions; and an insertion film located between the lower and upper electrodes, located in at least a part of an outer peripheral region of each of the resonance regions, and being not located in a center region of each of the resonance regions.

Abstract: An elastic wave device includes a multilayer body, an antenna terminal, a ground terminal, a signal terminal, an IDT electrode, and an insulating film. The multilayer body includes a support substrate and a piezoelectric film disposed on the support substrate. The antenna terminal is disposed on or above the support substrate. The ground terminal is directly disposed on the support substrate. The signal terminal is disposed above the support substrate. The IDT electrode is disposed on the piezoelectric film. The insulating film is disposed between the support substrate and the signal terminal. The multilayer body includes one of a layer made of a high acoustic-velocity material and an acoustic reflection layer.

Abstract: In a multiplexer, input or output terminals of four acoustic wave filters are connected to, among a plurality of terminals provided on piezoelectric substrates, antenna terminals connected to an antenna connection terminal; the four acoustic wave filters include a first acoustic wave filter and a second acoustic wave filter that is located at a farther position from the antenna connection terminal than a position of the first acoustic wave filter in a plan view of a substrate; and among the plurality of terminals, the terminals located at the closest position to the antenna connection terminal in the plan view of the substrate are connected to the second acoustic wave filter as the antenna terminals.

Abstract: A tunable filter includes a series-arm resonant circuit, and a parallel-arm resonant circuit. The series-arm resonant circuit includes a group of acoustic wave resonant circuits that have different resonant frequencies, a variable capacitor, and switching circuits. The parallel-arm resonant circuit includes another group of acoustic wave resonant circuits that have different resonant frequencies, a variable capacitor, and switching circuits. For example, the difference in pass-band frequency caused by the difference in resonant frequency between the acoustic wave resonant circuit in the group and the acoustic wave resonant circuit in the other group is greater than the maximum difference in pass-band frequency resulting from the variable range of capacitance of the variable capacitor.

Abstract: A quadplexer includes a first filter and a second filter having a pass band frequency that is higher than a pass band frequency of the first filter. The first filter includes series resonators disposed on a first path and parallel resonators disposed on a path that connects the first path and a ground to each other. A direction that connects ends of a plurality of electrode fingers defining each resonator crosses an elastic wave propagation direction at a predetermined angle. The series resonator nearest to a common terminal does not include first electrode fingers, and the other series resonators include the first electrode fingers.

Abstract: A product disclosed herein includes an RF filter die including an RF filter, a front side and a plurality of conductive bond pads conductively coupled to at least a portion of the RF filter, wherein at least a portion of the conductive bond pads is exposed on the front side of the RF filter die. The product also includes a TSV (Through-Substrate-Via) die that includes a plurality of conductive TSV contacts positioned on a back side of the TSV die and at least one conductive TSV (Through-Substrate-Via) structure that is conductively coupled to at least one of the plurality of conductive TSV contacts, wherein the back side of the TSV die is bonded to the front side of the RF filter such that the conductive bond pads on the RF filter die are conductively coupled to corresponding conductive TSV contacts positioned on the back side of the TSV die.

Abstract: A filter includes a series-arm resonator connected on a path connecting an input/output terminal and an input/output terminal, and first and second parallel-arm resonators connected between the same node on the path and ground. A resonant frequency of the first parallel-arm resonator is lower than a resonant frequency of the second parallel-arm resonator, and an anti-resonant frequency of the first parallel-arm resonator is lower than an anti-resonant frequency of the second parallel-arm resonator. The first parallel-arm resonator is defined by an acoustic wave resonator, and includes an IDT electrode that excites an acoustic wave, and a reflector that reflects the acoustic wave excited by the IDT electrode. A pitch between the IDT electrode and the reflector is about 0.42? or more and less than about 0.50?.

Abstract: A chip package structure includes a chip package layer and at least one conductive structure layer. The chip package layer includes at least one chip and an encapsulant. The chip has an upper surface, and the encapsulant is used to encapsulate the chip and expose the upper surface. The conductive structure layer includes a plurality of first conductive pillars and a plurality of second conductive pillars. The first conductive pillars are disposed on the upper surface, the second conductive pillars are disposed on the upper surface and located between an edge of the upper surface and the first conductive pillars. A density of the second conductive pillars along an extending direction of the edge is greater than or equal to 1.2 times of a density of the first conductive pillars along the extending direction of the edge.

Abstract: An elastic wave device includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate and including first and second busbars and first and second electrode fingers connected to the first and second busbars, a bump electrode electrically connected to the IDT electrode, a protective film covering the IDT electrode, and a heat-conductive material layer that has an insulating property and that is provided only in a region excluding an excitation region of any IDT electrode and a region located above the bump electrode.

Abstract: A ladder filter includes serial arm resonators disposed along a serial arm and parallel arm resonators disposed along corresponding parallel arms. Ladder circuit units are disposed along a path from an input terminal, which is a first end, to an output terminal, which is a second end. Each of the ladder circuit units includes a single serial arm resonator and a single parallel arm resonator. The ladder circuit units are mirror-connected to one another. The impedance at the first end is different from the impedance at the second end.

Abstract: In order to suppress an interference frequency in a ladder-type filter, an additional resonator (RZ1) that acts as a capacitance is connected in parallel to a series resonator (S1). The antiresonance of the additional resonator creates an additional pole in order for the interference frequency to be attenuated more effectively.

Abstract: Communication system includes first unit; and second unit(s) having processing unit(s), downstream signal path(s), and upstream signal path(s). First unit communicates downstream digital transport signal (including digital representation of original downstream RF signal received at first unit) to second unit(s). Second unit uses processing unit and downstream signal path to generate downstream RF signal (for radiation from antenna) from downstream digital transport signal; and communicates upstream digital transport signal (generated from upstream RF signal received at second unit(s) using processing unit(s) and upstream signal path(s)) to first unit. Upstream digital transport signal includes digital representation of received upstream RF signal. Feedback path digitizes downstream RF signal(s) to provide digital representation(s) of downstream RF signal radiated from antenna to processing unit(s).

Abstract: An elastic wave device includes a first filter including an elastic wave resonator and a second filter connected to an antenna common terminal via a common node. When a first pass band of the first filter and second pass bands of the second filters are F1 and F2, respectively, F1<F2. The first filter includes at least one elastic wave resonator, and the elastic wave resonator uses Rayleigh waves propagating on a piezoelectric substrate made of LiNbO3, IDT electrodes including a Pt film on a piezoelectric layer made of LiNbO3, and a silicon oxide film covering the IDT electrodes. The thickness of the silicon oxide layer is about 33% or less of the wavelength of the IDT electrodes.

Abstract: An elastic wave device includes IDT electrodes on a first main surface of a piezoelectric substrate and a heat dissipating film on a second main surface and including a pair of opposing main surfaces and side surfaces connecting the pair of main surfaces. At least a portion of the side surfaces of the heat dissipating film is located in an inner side portion relative to the outer circumference of the second main surface of the piezoelectric substrate on an arbitrary cross section along a direction connecting the pair of main surfaces of the heat dissipating film.

Abstract: A filter includes a longitudinally coupled resonator device, a parallel arm resonator, and a variable frequency circuit. The parallel arm resonator is connected between a ground and a node provided on a path connecting input-output terminals. The variable frequency circuit is connected to the first parallel arm resonator. The longitudinally coupled resonator device includes three or more odd-number IDT electrodes, an odd-numbered IDT terminal, and an even-numbered IDT terminal. The even-numbered IDT terminal is a first signal terminal connected to at least one IDT electrode located at an even-numbered position from an edge of an arrangement order of the plural IDT electrodes. The odd-numbered IDT terminal is a second signal terminal connected to two or more IDT electrodes located at odd-numbered positions from the edge. The longitudinally coupled resonator device is disposed so that the even-numbered IDT terminal is connected to the node.

Abstract: A multiplexer includes: a first filter that includes a piezoelectric thin film resonator and is connected between a common terminal and a first terminal, the piezoelectric thin film resonator being located on a substrate; a second filter that includes an acoustic wave resonator and is connected between the common terminal and a second terminal, the acoustic wave resonator including an IDT located on a piezoelectric substrate; and a capacitor that includes a pair of electrodes facing each other in a planar direction and is coupled to the first filter, the pair of electrodes being located on the piezoelectric substrate.

Abstract: A multiplexer includes a first filter, a second filter, a combining wiring line that provides a combination point at which an input or an output of each of the first filter and the second filter is connected to each other, an antenna terminal to connect the multiplexer to an antenna, an antenna wiring line connected at one end to the antenna terminal and connected at the other end to the combining wiring line, a matching terminal to which a matching inductor to provide matching between the antenna and the multiplexer is to be connected, and a matching wiring line to be connected at one end to the matching terminal and connected at the other end to the combining wiring line.

Abstract: An elastic wave apparatus includes a multilayer substrate, first through fourth band pass filters, an antenna terminal, and first and second inductors. The multilayer substrate includes first through sixth wiring layers. The first through fourth band pass filters are disposed on the multilayer substrate and are connected to a common node. The antenna terminal is connected to an antenna and also to the common node. The first inductor is connected to the antenna terminal. The second inductor is connected between the first band pass filter and the common node. The first inductor is disposed on the fourth and fifth wiring layers. The second inductor is disposed on the second and third wiring layers which are different from the fourth and fifth wiring layers. The first and second inductors overlap each other at least partially as viewed from above.

Abstract: A multiplexer includes: first and second substrate respectively having first and second surfaces facing each other across an air gap; a first filter including first resonators located on the first surface and connected between a common terminal and a first terminal; a second filter including second resonators located on the second surface and connected between the common terminal and a second terminal, a first resonator connected in series between the common terminal and the first terminal and closest to the common terminal overlapping with a second resonator connected in series between the common terminal and the second terminal and closest to the common terminal, first resonators other than the first resonator closest to the common terminal not overlapping with the second resonators, second resonators other than the second resonator closest to the common terminal not overlapping with the first resonators.

Abstract: A branching filter includes a first band-pass filter provided between a common port and a first signal port, and a second band-pass filter provided between the common port and a second signal port. The first band-pass filter includes a first LC resonant circuit and a first resonant circuit section. The first resonant circuit section includes a first acoustic wave resonator. The second band-pass filter includes a second LC resonant circuit and a second resonant circuit section. The second resonant circuit section includes a second acoustic wave resonator and an inductor connected in parallel.

Abstract: Bulk Acoustic Wave (BAW) resonators with a Border (BO) ring and an inner ring are provided. One BAW resonator includes a bottom electrode, a piezoelectric layer over the bottom electrode, and a top electrode over the piezoelectric layer in which an active region is formed where the top electrode and the bottom electrode overlap. The top electrode includes a BO ring extending about a periphery of the active region and an inner ring inside of and spaced apart from the BO ring. The BO ring is a mass loading of a first portion of the top electrode and the inner ring is a mass unloading of a second portion of the top electrode. Various methods include fabricating a BAW resonator with a top electrode including a mass loading BO ring and a mass unloading inner ring spaced apart from the mass loading BO ring.

Abstract: Aspects of this disclosure relate to a multiplexer, such as a duplexer, a quadplexer, a hexaplexer, or the like. The multiplexer includes acoustic wave filters coupled to a common node. A first acoustic wave filter of the acoustic wave filters includes acoustic wave resonators of a first type and a series acoustic wave resonator of a second type coupled between the acoustic wave resonators of the first type and the common node.

Abstract: According to one embodiment, a wireless communication device includes a first surface, a power storage unit, an antenna board, a circuit board, a wireless communication unit and a signal line. The power storage unit has a second surface located oppositely to the first surface. The antenna board implemented with an antenna faces the first surface. The circuit board faces the second surface of the power storage unit. The wireless communication unit is implemented to the circuit board and is located oppositely to a surface facing the power storage. The signal line connects the antenna board and the wireless communication unit.

Abstract: A filter includes a series-arm resonator connected to a path connecting input/output terminals, and first and second parallel-arm resonators connected between the same node on the path and ground. A resonant frequency of the second parallel-arm resonator is higher than a resonant frequency of the first parallel-arm resonator, and an anti-resonant frequency of the second parallel-arm resonator is higher than an anti-resonant frequency of the first parallel-arm resonator. The second parallel-arm resonator includes an IDT electrode that excites an acoustic wave, and does not include a reflector.