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.

Abstract: A circuit having a power amplifier port, an antenna port, and a ladder network coupled between the power amplifier and antenna ports is disclosed. The ladder network includes a proximal series acoustic resonator coupled to the power amplifier port, a distal series acoustic resonator coupled to the antenna port, and at least one series acoustic resonator coupled between the proximal series acoustic resonator and the distal series acoustic resonator. A first shunt acoustic resonator is coupled between a fixed voltage node and the proximal series acoustic resonator and the at least one series acoustic resonator. A second shunt acoustic resonator is coupled between the fixed voltage node and a second node to which the at least one series acoustic resonator is also coupled. A first inductor is coupled in parallel with the proximal series acoustic resonator to create notches below and above a passband of the ladder network.

Abstract: A filter device including a first filter having a first passband, and a second filter having a second passband, the first and second filters each being connected between a common contact and a respective signal contact, and the filter device configured to reduce spurious emissions generated in one filter due to propagation of Lamb waves in the other filter. In one example the first filter includes a SAW filter formed on a piezoelectric substrate, a SAW resonator formed on the piezoelectric substrate and connected in series between the common contact and the SAW filter, and a dielectric film formed over the piezoelectric substrate covering the SAW filter and the SAW resonator. The dielectric film has a first thickness over the SAW filter and a second, lesser, thickness over the SAW resonator, a difference between the first and second thicknesses being selected to suppress spurious emissions in the second passband generated by propagation of a Lamb wave in the SAW filter.

Abstract: A magnetoresistive effect device including a magnetoresistive effect element with which a high-frequency filter can be realized is provided. Magnetoresistive effect device includes: at least one magnetoresistive effect element including a magnetization fixed layer, spacer layer, and magnetization free layer in which magnetization direction is changeable; first and second port; signal line; and direct-current input terminal. First and second ports are connected to each other via signal line. Magnetoresistive effect element is connected to signal line and is to be connected to ground in parallel to second port. Direct-current input terminal is connected to signal line. A closed circuit including magnetoresistive effect element, signal line, ground, and direct-current input terminal is to be formed.

Abstract: Aspects of this disclosure relate to an acoustic wave device that includes an acoustic obstacle disposed between canceling circuits coupled to one or more acoustic wave filters. The canceling circuits can cancel frequency components within different frequency bands. The acoustic obstacle can reduce acoustic coupling between the canceling circuits by scattering and/or absorbing acoustic energy.

Abstract: Aspects and examples provide improvement in the attenuation level near the passband within the stopband of the bandpass-type filter using a ladder-type circuit formed by a BAW resonator. In one example the filter includes a ladder-type circuit formed by a bulk acoustic wave (BAW) resonator, and a loop circuit connected between two distinct points on a signal path extending from an input to an output of the ladder-type circuit for phase-cancellation of signals at the two distinct points. The two distinct points may be the input and the output of the ladder-type circuit. The loop circuit may include a SAW resonator or a BAW resonator. The BAW resonator may be a film bulk acoustic resonator (FBAR) or solidly mounted resonator (SMR).

Abstract: A filter includes: series resonators connected to each other in series; shunt resonators connected to first nodes between some of the series resonators; and a variable capacitor connected to a second node between some of the series resonators, and forming a pole configured to suppress harmonics.

Abstract: A high frequency module improved in heat dissipation performance includes: a dielectric multilayer substrate including a ground layer and a high frequency electronic component mounted thereon while being in contact with the ground layer, the high frequency electronic component including a heat generating portion; and a cutoff block formed of an upstanding wall portion and a cover portion covering the upstanding wall portion, the cutoff block housing the high frequency electronic component and including a hollow portion having a cutoff characteristic at a frequency of a high frequency signal used by the high frequency electronic component, and the upstanding wall portion of the cutoff block being in contact with the ground layer of the dielectric multilayer substrate.

Abstract: An acoustic wave filter includes series resonators and parallel resonators that have a piezoelectric film on an identical substrate and have a lower electrode and an upper electrode, wherein: one of the series resonators and the parallel resonators have a temperature compensation film on a face of the lower electrode or the upper electrode that is opposite to the piezoelectric film in a resonance region, the compensation film having an elastic constant of a temperature coefficient of which sign is opposite to a sign of a temperature coefficient of an elastic constant of the piezoelectric film; and the other have an added film on the same side as the temperature compensation film on the lower electrode side or the upper electrode side compared to the piezoelectric film in the resonance region in the one of the series resonators and the parallel resonators.

Abstract: A composite filter device includes a first filter and a plurality of second filters with different passbands. End portions of the first filter and the plurality of second filters are connected to a common connection. The first filter includes a piezoelectric substrate made of LiNbO3, an IDT electrode provided on the piezoelectric substrate, and a dielectric layer provided on the piezoelectric substrate so as to cover the IDT electrode. The first filter utilizes a fundamental wave of Rayleigh waves. The passband of the first filter is arranged in a frequency band that is lower than any of the passbands of the plurality of second filters.

Abstract: Embodiments of a Surface Acoustic Wave (SAW) device and methods of fabrication thereof are disclosed. In some embodiments, a SAW device includes a quartz carrier substrate, a piezoelectric layer on a surface of the quartz carrier substrate, and at least one interdigitated transducer on a surface of the piezoelectric layer opposite the quartz carrier substrate, wherein a thickness of the piezoelectric layer is less than twice a transducer electrode period of the at least one interdigitated transducer. Using the piezoelectric layer on the carrier substrate suppresses acoustic radiation into the bulk, thereby improving the performance of the SAW device. Further, by utilizing quartz for the carrier substrate, additional advantages of small viscous losses, small permittivity, and small thermal sensitivity are achieved. Still further, as compared to Silicon, the use of quartz for the carrier substrate eliminates resistive losses.

Abstract: An acoustic wave device includes an acoustic wave generator spaced apart from a support layer and disposed on a substrate; a protective member coupled to the support layer and spaced apart from the acoustic wave generator by a predetermined distance; and a sealing component sealing the protective member.

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 method for designing a narrowband acoustic wave microwave filter including: generating a modeled filter circuit design having circuit elements including an acoustic resonant element defined by an electrical circuit model that includes a parallel static branch, a parallel motional branch, and one or both of a parallel Bragg Band branch that models an upper Bragg Band discontinuity and a parallel bulk mode function that models an acoustic bulk mode loss; and generating a final circuit design. Generating the final circuit design includes optimizing the modeled filter circuit design to generate an optimized filter circuit design; comparing a frequency response of the optimized filter circuit design to requirements; selecting the optimized filter circuit design for construction into the actual acoustic microwave filter based on the comparison; and transforming the optimized filter circuit design to a design description file for input to a construction process.

Abstract: A multiband radio frequency transmitter of a transceiver in which a receiving band is varied, includes a transmitting circuit, a receiving band-rejection filter, a power amplifying circuit, and an impedance compensating circuit. The transmitting circuit is configured to generate a transmission signal. The receiving band-rejection filter is configured to vary a rejection band in response to a variation of the receiving band, and reject the receiving band from the transmission signal provided from the transmitting circuit. The power amplifying circuit is configured to amplify the transmission signal that passes through the receiving band-rejection filter. The impedance compensating circuit is configured to compensate for impedance mismatch due to the variation of the rejection band of the receiving band-rejection filter.

Abstract: A duplexer includes first and second filter circuits and first and second wirings. The first filter circuit allows a signal of a first frequency band to pass therethrough between a first terminal and a common terminal and includes a first resonator which is connected at one end to a line disposed between the first terminal and the common terminal to branch off from the line. The second filter circuit allows a signal of a second frequency band, which is different from the first frequency band, to pass therethrough between a second terminal and the common terminal. The first wiring is connected at one end to the common terminal and is opened at the other end. The second wiring is connected at one end to the other end of the first resonator and is grounded at the other end. The first wiring is electromagnetically coupled with second wiring.

Abstract: A communication module includes a serial resonator of a transmission filter and an auxiliary resonator of a reception filter. Each of the serial resonator and the auxiliary resonator includes a piezoelectric substrate and a positive-side comb-shaped electrode and negative-side comb-shaped electrode meshing with each other. The positive-side comb-shaped electrode in the transmission filter and the negative-side comb-shaped electrode in the reception filter are connected to each other. The orientation from the positive-side comb-shaped electrode to the negative-side comb-shaped electrode relative to the crystal orientation of the piezoelectric substrate in the transmission filter and the orientation from the negative-side comb-shaped electrode to the positive-side comb-shaped electrode relative to the crystal orientation of the piezoelectric substrate in the reception filter are inverse to each other.

Abstract: An elastic wave device includes a piezoelectric substrate, IDT electrodes disposed on the piezoelectric substrate, a first wiring line, an insulating layer covering at least a portion of the first wiring line, a second wiring line at least a portion of which is disposed on the insulating layer to provide a three-dimensional crossing portion, a peripheral support including a cavity surrounding the IDT electrodes, the first and second wiring lines, and the insulating layer, a partition support disposed in the cavity, and a cover disposed on the peripheral support and the partition support to cover the cavity. The second wiring line includes a step portion electrically connecting a portion of the second wiring line located on the piezoelectric substrate and a portion of the second wiring line located on the insulating layer to each other. The partition support covers the step portion.

Abstract: An acoustic wave device includes: a first piezoelectric substrate; a first IDT that includes a plurality of first electrode fingers and is located on a first surface of the first piezoelectric substrate; a second piezoelectric substrate that is located above the first surface; and a second IDT that is located on a second surface of the second piezoelectric substrate, and includes a plurality of second electrode fingers that are non-parallel to the plurality of first electrode fingers, the second surface of the second piezoelectric substrate facing the first surface across an air gap.

Abstract: An acoustic wave filter device includes a lower electrode disposed between a substrate and a piezoelectric layer, an upper electrode disposed on the piezoelectric layer, and an insulating layer disposed on the upper electrode. The insulating layer exposes portions of the upper electrode.

Abstract: A high-frequency module includes a multilayer substrate that includes an insulator layer and a wiring electrode, a component on one main surface of the multilayer substrate, a resin layer on the one main surface so as to cover the component, and a shield electrode covering at least a portion of a surface of the resin layer and at least a portion of a side surface of the multilayer substrate. The wiring electrode includes a capacitor via electrode that is spaced away from the shield electrode inside the multilayer substrate, and a first capacitor is defined by the shield electrode and the capacitor via electrode.

Abstract: One embodiment is directed to a distributed antenna system comprising a host unit and at least one remote antenna unit that is communicatively coupled to the host unit. The host unit is configured to communicate a downstream transport signal from the host unit to the remote antenna unit. The remote antenna unit to which the downstream transport signal is communicated uses the downstream transport signal to generate a downstream radio frequency signal for radiation from an antenna associated with the remote antenna unit. The remote antenna unit is configured to communicate an upstream transport signal from the remote antenna unit to the host unit, wherein the upstream transport signal is generated from a received upstream radio frequency signal received at the remote antenna unit.

Abstract: A first attenuation circuit is connected between a node and ground, and the node is located between a ladder resonance circuit and a transmitter-side terminal. A second attenuation circuit is connected between a first parallel arm resonator of the ladder resonance circuit and ground and is connected in series to the first parallel arm resonator. The first attenuation circuit includes a second parallel arm resonator and a first switch that switches between a first state in which the second parallel arm resonator is connected to the node and a second state in which the first switch is open. The second attenuation circuit includes a capacitor and a second switch that switches between a first state in which the capacitor is connected to the first parallel arm resonator and a second state in which the first parallel arm resonator is connected to ground.

Abstract: A multiplexer is provided on a mounting substrate and includes a duplexer with first and second bandpass filters, and at least one bandpass filter other than the duplexer. The first and second bandpass filters respectively include first and second multilayer bodies that are different components. Configurations of the first and second multilayer bodies are different from each other such that a frequency range of high-order mode spurious radiation generated in the duplexer and a pass band of the bandpass filter other than the duplexer is different from each other.

Abstract: An acoustic wave resonator includes: a piezoelectric substrate; and an IDT located on the piezoelectric substrate and including a pair of comb-shaped electrodes facing each other, each of the pair of comb-shaped electrodes including a grating electrode exciting an acoustic wave and a bus bar to which the grating electrode is connected, wherein an anisotropy coefficient in a cross region where the grating electrodes of the pair of comb-shaped electrodes cross each other is positive; an anisotropy coefficient in a gap region located between a tip of the grating electrode of one of the pair of comb-shaped electrodes and the bus bar of the other is less than the anisotropy coefficient in the cross region, and an acoustic velocity of an acoustic wave propagating through the gap region is equal to or less than an acoustic velocity of an acoustic wave propagating through the cross region at an antiresonant frequency.

Abstract: A multiplexer includes a transmission filter and a reception filter that are connected to a common terminal, and a cancellation circuit that is connected to the common terminal and a node on a transmission path and that offsets a component in a certain frequency band flowing through the transmission filter. The cancellation circuit includes a capacitive element connected to the common terminal, and a longitudinally-coupled resonator including a first end connected to the capacitive element and a second end connected to the node with no capacitive element interposed therebetween. An impedance in a reception band when viewing the cancellation circuit from the common terminal side is higher than an impedance in the reception band when viewing the cancellation circuit from the node side.

Abstract: Embodiments of the disclosure are directed to a Bulk Acoustic Wave (BAW) filter structure with internal electrostatic shielding. In exemplary aspects disclosed herein, a shielded BAW filter structure includes a substrate, a plurality of transducers over the substrate, and a planar electrostatic shield between the substrate and a top electrode of the plurality of transducers. Each of the plurality of transducers forms a portion of a BAW resonator and resides in a filter including a parasitic capacitance. The planar electrostatic shield is coupled to a ground node and interrupts an electrical field associated with the parasitic capacitance of the filter to reduce the parasitic capacitance. Accordingly, the shielded BAW filter structure reduces the influence of parasitic capacitance providing improved filtering performance compared to an unshielded BAW filter structure.

Abstract: A high frequency module includes a duplexer that includes a transmission filter, a receive-only filter, and a power amplifier that power-amplifies a transmission signal. In order to improve the isolation characteristics between a transmission signal and a reception signal at the duplexer, the receive-only filter is arranged between the power amplifier and the duplexer.

Abstract: A filter circuit is provided which allows the pass band to be tuned to a desired communication signal while achieving increased attenuation in a given frequency band that lies outside the pass band. A filter circuit includes a fixed filter and a tunable filter. The fixed filter has a pass band wider than a frequency band corresponding to a predetermined communication signal and overlapping with the frequency band corresponding to the communication signal. The tunable filter has a stop band narrower than the pass band of the fixed filter and having tunable frequency. The fixed filter and the tunable filter are connected in series.

Abstract: A method of designing an acoustic microwave filter comprises generating a proposed filter circuit design having an acoustic resonant element with a defined admittance value, introducing a lumped capacitive element in parallel and a lumped inductive element in series with the resonant element, selecting a first capacitance value for the capacitive element and a first inductance value for the inductive element, thereby creating a first temperature modeled filter circuit design, simulating the first temperature modeled filter circuit design at a first operating temperature, thereby generating a first frequency response, selecting a second capacitance value for the capacitive element and a second inductance value for the inductive element, thereby creating a second temperature modeled filter circuit design, simulating the second temperature modeled filter circuit design at a second operating temperature, thereby generating a second frequency response, and comparing the first and second frequency responses to the

Abstract: An elastic wave filter includes a piezoelectric substrate, an IDT electrode provided on the piezoelectric substrate, a first shield electrode provided on the piezoelectric substrate, a first insulating film laminated on the piezoelectric substrate and extending onto the first shield electrode, a first signal terminal provided on the first insulating film, a second signal terminal provided on the piezoelectric substrate, and a first ground terminal provided on the piezoelectric substrate and connected to a ground potential. The first shield electrode is not electrically connected to the IDT electrode and the first and second signal terminals. The first signal terminal is included in the first shield electrode when seen from above. One of the first signal terminal and the second signal terminal is an output terminal and the other thereof is an input terminal.

Abstract: In a band pass filter, a first elastic wave resonator includes a first base board type and a first electrode configuration significantly improved or optimal for frequency characteristics of the first elastic wave resonator, and a second elastic wave resonator includes a second base board type and a second electrode configuration significantly improved or optimal for frequency characteristics of the second elastic wave resonator. A first attenuation pole provided by the first elastic wave resonator and a second attenuation pole provided by the second elastic wave resonator is steeper than if the first elastic wave resonator and the second elastic wave resonator that have different frequency characteristics include electrodes having the same configuration on the same types of base boards.

Abstract: In one implementation, an analytical approach to determining an improved and/or optimal design of a matching network in a capacitive or inductive WPT system is provided. In one implementation, for example, a framework is provided to enable stage(s) of the network to simultaneously provide gain and compensation. The multistage matching network efficiency can be improved and/or optimized, such as by using the method of Lagrange multipliers, resulting in the optimum distribution of gain and compensation among the L-section stages.

Abstract: A piezoelectric vibrator that includes a piezoelectric film with a pair of electrodes disposed on opposing sides of the piezoelectric film. Moreover, the vibrator includes first and second adjustment films with the first adjustment film covering the first surface of the piezoelectric film in a first region and the second adjustment film covering the first surface of the piezoelectric film in a second region that is different from the first region. Moreover, the second region of the piezoelectric film has a greater displacement than the first region when the piezoelectric vibrator vibrates.

Abstract: A multiplexer includes a common terminal, a Band66 transmission-side filter, a Band30 transmission-side filter, and an inductance element. The Band66 transmission-side filter includes series arm resonators and parallel arm resonators. The frequency of spurious waves generated by the Band66 transmission-side filter is included in a pass band of the Band30 transmission-side filter. A transmission output terminal is connected to a common terminal with the inductance element interposed therebetween and is directly connected to one parallel arm resonator. The one parallel arm resonator has a largest capacitance, among the parallel arm resonators.

Abstract: For a reactance filter constructed from serial and parallel resonators, in order to improve the linearity, it is proposed to connect a capacitor in series or in parallel either with a parallel resonator or a cascade of parallel resonators or with a series resonator or a cascade of series resonators.

Abstract: A bulk acoustic wave resonator includes: a substrate; a cavity forming layer disposed on the substrate so as to form a cavity; a lower electrode disposed on the cavity; a piezoelectric layer disposed on the lower electrode; an upper electrode disposed on the piezoelectric layer; and a temperature compensation layer disposed below the lower electrode and in the cavity portion.

Abstract: Provided are a resin sheet, for sealing an electronic device, which is not easily shifted out of position; and a method for manufacturing an electronic-device package. This resin sheet, for sealing an electronic device, has a probe tack of 5 to 500 g at 25° C. The tack is measured, using a probe having a diameter of 25 mm.

Abstract: Embodiments of radio frequency (RF) filtering circuitry are disclosed. In one embodiment, the RF filtering circuitry includes a common port, a second port, a third port, a first RF filter path, and a second RF filter path. The first RF filter path is connected between the common port and the second port and comprises a first pair of resonators and a first acoustic wave resonator. One of the first pair of resonators also includes a second acoustic wave resonator. The second RF filter path is connected between the common port and the third port. The second RF filter path includes a second pair of resonators. The first and second acoustic wave resonators of the first RF filter path increase roll-off greatly with respect to just an LC filter, and thereby allow for an increase out-of-band rejection at high frequency ranges.

Abstract: An electro-acoustic transducer and an electro-acoustic component including an electro-acoustic transducer are disclosed. In an embodiment the transducer includes a first and a second bus bar, a plurality of electrode fingers and a plurality of two or more sub tracks, wherein each electrode finger is electrically connected to one of the bus bars, wherein each sub track extends along a longitudinal direction, wherein all sub tracks are arranged one next to another in a transversal direction, wherein at least a first of the sub tracks includes segments of the electrode fingers and has an associated sub track with segments of the electrode fingers, wherein the segments of the electrode fingers of the first sub track are shifted by a distance S=?/2 along the longitudinal direction relative to the segments of the electrode fingers of the associated sub track, and wherein ? is an acoustic wavelength.

Abstract: A composite filter apparatus includes a common terminal, a transmission-side terminal, a reception-side terminal, a transmission filter, and a reception filter with a pass band higher than the pass band of the transmission filter. The transmission filter is connected between the common terminal and the transmission-side terminal and the reception filter is connected between the common terminal and the reception-side terminal. An inductor is provided between the common terminal and the reception filter in a path between the common terminal and the reception-side terminal. The resonant frequency of a parallel-arm resonator closest to the common terminal in the reception filter is lower than a high end frequency of the pass band of the transmission filter and is lower than the resonant frequencies of the other parallel-arm resonators in the reception filter.

Abstract: Methods to design band-pass acoustic wave microwave filters are disclosed. A performance metric related to an input impedance of a baseline filter design is calculated, the baseline filter design including a plurality of series surface acoustic wave resonators and a plurality of shunt surface acoustic wave resonators, each surface acoustic wave resonator having a respective resonant frequency. One or more alternative filter designs is established, each alternative filter design derived from the baseline filter design by reordering the resonant frequencies of two or more of the plurality of series surface acoustic wave resonators and/or two or more of the plurality of shunt surface acoustic wave resonators. A respective performance metric related to an input impedance of each alternative filter designs is calculated. A final filter design is selected from among the baseline filter design and the alternative filter designs based on the respective performance metrics.

Abstract: An acoustic wave resonator includes: a piezoelectric substrate; and a pair of grating electrodes that is formed on the piezoelectric substrate, one of the pair of grating electrodes including a plurality of first electrode fingers having electric potentials equal to each other, another of the pair of grating electrodes including a plurality of second electrode fingers having electric potentials that differ from the electric potentials of the plurality of first electrode fingers and are equal to each other, two second electrode fingers of the plurality of second electrode fingers being located between at least a pair of adjacent first electrode fingers of the plurality of first electrode fingers, Pg differing from ?/4 where ? represents a wavelength of an acoustic wave excited by the plurality of first electrode fingers and the plurality of second electrode fingers and Pg represents a distance between centers of the two second electrode fingers.

Abstract: An acoustic wave resonator includes: a piezoelectric substrate; an IDT located on the piezoelectric substrate and including comb-shaped electrodes facing each other, each of the comb-shaped electrodes including: electrode fingers exciting an acoustic wave; and a bus bar to which the electrode fingers are connected; a dielectric film located on the piezoelectric substrate in an overlap region, where the electrode fingers of one of the comb-shaped electrodes and the electrode fingers of the other overlap, so as to cover the electrode fingers; and an additional film located on the dielectric film in the overlap region and having a density greater than that of the dielectric film, and of which a film thickness in edge regions corresponding to both edges of the overlap region in an extension direction of the electrode fingers is greater than a film thickness in a central region sandwiched between the edge regions in the overlap region.

Abstract: A duplexer and a quadplexer are disclosed. In an embodiment, the duplexer includes an antenna terminal and two sub-paths including a transmit path and a receive path, the two sub-paths being connected to the antenna terminal, wherein the transmit path includes serially interconnected series resonators and, in parallel therewith, n parallel paths connected to ground, wherein each parallel path includes one parallel resonator or a cascade of serially interconnected parallel resonators, wherein n is an integral number with 0<n<8, wherein at least one of the n parallel resonators is connected to ground in series with an inductance in the transmit path, and wherein a parallel resonator is connected directly to ground in a first parallel path that is nearest to the antenna terminal and no inductance is arranged in the first parallel path.

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 provided in series. 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 provided in series. The second resonant circuit section includes a second acoustic wave resonator and an inductor connected in parallel.