Abstract: An elastic wave filter device includes first and second signal terminals, an inductor, and a ladder elastic wave filter unit. The elastic wave filter device includes an elastic wave filter chip provided with the ladder elastic wave filter unit and a wiring board. The wiring board includes a plurality of dielectric layers and a plurality of electrode layers alternately laminated. An inductor electrode and a ground electrode are arranged so as to not face each other via the dielectric layer.

Abstract: An elastic wave filter has first, second, and third IDT electrodes whose wiring electrodes are connected to unbalanced signal terminal; fourth IDT electrode disposed between the first and second IDT electrodes; fifth IDT electrode disposed between the second and third IDT electrodes; and first and second balanced signal terminals connected to the wiring electrodes of fourth and fifth IDT electrodes, respectively. The ground electrodes of the first through fifth IDT electrodes are connected to the ground. Signals in opposite phase and in phase with a signal input to unbalanced signal terminal are output from first and second balanced signal terminals, respectively. The wiring electrodes of second and third IDT electrodes are adjacent to the ground electrode of fifth IDT electrode. The wiring electrode of one of first and second IDT electrodes is adjacent to the wiring electrode of fourth IDT electrode. The ground electrode of the other is adjacent to the ground electrode of fourth IDT electrode.

Abstract: In an elastic wave demultiplexer having excellent isolation characteristics, a first ground wiring electrode is connected to a second ground wiring electrode, via first ground via-hole electrodes. The first ground wiring electrode is connected to ground land electrodes via second ground via-hole electrodes. The second ground wiring electrode is connected to a ground terminal via third ground via-hole electrodes. The number of the first ground via-hole electrodes is greater than the number of the second ground via-hole electrodes and the number of the third ground via-hole electrodes.

Abstract: A surface acoustic wave resonator includes: an IDT which is disposed on a quartz crystal substrate with an Euler angle of (?1.5°???1.5°, 117°???142°, 41.9°?|?|?49.57°) and which excites a surface acoustic wave in an upper mode of a stop band; and an inter-electrode-finger groove formed by recessing the quartz crystal substrate between electrode fingers of the IDT, wherein the following expression: 0.01??G where ? represents a wavelength of the surface acoustic wave and G represents a depth of the inter-electrode-finger groove, is satisfied and when a line occupancy of the IDT is ?, the depth of the inter-electrode-finger groove G and the line occupancy ? are set to satisfy the following expression: ?2.5×G/?+0.675????2.5×G/?+0.775.

Abstract: An acoustic wave resonator includes a piezoelectric substrate and first and second comb-shaped electrodes provided on the piezoelectric substrate and interdigitating with each other. The first comb-shaped electrode includes a first busbar and first electrode fingers extending in a direction non-perpendicular to a direction in which the first busbar extends. The second comb-shaped electrode includes a second busbar and second electrode fingers extending from the second busbar and interdigitating with the first electrode fingers at an interdigitating region. This acoustic wave resonator can suppress a spurious response due to a transverse mode and has a high Q value.

Abstract: An elastic wave filter that prevents damage caused by ESD is constructed such that a distance between an electrode finger or a dummy electrode of a first IDT electrode and an adjacent electrode finger or an adjacent dummy electrode of a fourth comb-shaped electrode, which is a floating electrode that is not connected to any of an input terminal, output terminals, and a ground terminal, is longer than a distance between the electrode finger or the dummy electrode of the first IDT electrode and an adjacent electrode finger or an adjacent dummy electrode of a third comb-shaped electrode, which is connected to the input terminal, the output terminal, or the ground terminal.

Abstract: A surface acoustic wave (SAW) filter device includes an input port for receiving an unbalanced signal, a pair of input/output ports, a first SAW filter for receiving the unbalanced signal from the input port and outputting balanced signals to the pair of input/output ports, a second SAW filter for receiving the balanced signals output from the pair of input/output ports and outputting balanced signals, and a pair of output ports for outputting the balanced signals output from the second SAW filter. The first SAW filter includes a first longitudinally-coupled SAW resonator having a first unbalanced signal input port and first and second balanced signal output ports, and a second longitudinally-coupled SAW resonator having a second unbalanced signal input port and third and fourth balanced signal output port. The first and second unbalanced signal input ports are electrically connected to the input port.

Abstract: An acoustic filter and method of acoustic filter manufacture provides a plurality of series acoustic resonators coupled in series on a first resonator substrate, a plurality of shunt resonators on a second resonator substrate, and a support substrate. The first and second resonator substrates are mounted on the support substrate. The filter further provides a plurality of electrical connections, wherein each respective electrical connection electrically couples a respective one of the plurality of shunt resonators to a respective one of the plurality of series acoustic resonators.

Abstract: An acoustic wave resonance device includes: piezoelectric substrate (1), first acoustic wave resonator (100) provided on an upper surface of piezoelectric substrate (1) and including first interdigital transducer electrode (110), and second acoustic wave resonator (200) provided on piezoelectric substrate (1) and including second interdigital transducer electrode (210). First acoustic wave resonator (100) and second acoustic wave resonator (200) are connected to each other. An overlap width of a plurality of first comb-shaped electrodes (112) forming first acoustic wave resonator (100) is larger than an overlap width of a plurality of second comb-shaped electrodes (212) forming second acoustic wave resonator (200). With such a configuration, frequencies in which a transverse mode spurious response is generated can be distributed and loss can be reduced.

Abstract: A ladder-type surface acoustic wave filter includes a first series resonator having the lowest resonance frequency among a plurality of series resonators; and a second series resonator having a resonance frequency higher than the first series resonator. The film thickness of a dielectric film in the region where the first series resonator is formed is larger than that of a dielectric film in the region where the second series resonator is formed.

Abstract: An elastic wave surface acoustic wave duplexer includes an antenna terminal, a transmission filter, a reception filter, and a plurality of elastic wave resonators connected in series between the antenna terminal and the reception filter. The reception filter is a longitudinally coupled resonator-type surface acoustic wave filter including a plurality of IDT electrodes and arranged along a propagation direction of elastic wave. A combined capacitance of the plurality of surface acoustic wave resonators is smaller than a capacitance of the IDT electrodes and included in the plurality of IDT electrodes and connected to the antenna terminal.

Abstract: A surface acoustic wave device includes a first filter and a second filter, each of them being a surface acoustic wave (SAW) filter including an odd number of at least three InterDigital Transducers (IDTs); an unbalanced terminal to which an unbalanced signal is input; a first balanced terminal from which a signal having a same phase as the unbalanced signal is output; and a second balanced terminal from which a signal having an opposite phase to the unbalanced signal is output. One of electrodes of a first center IDT and one of electrodes of a second center IDT are commonly connected to the unbalanced terminal, the first center IDT and the second center IDT being one out of the odd number of IDTs and locating at a center in the first filter and the second filter respectively. The number of electrode fingers of the first center IDT is an odd number, and the number of electrode fingers of the second center IDT is an even number.

Abstract: An elastic wave device includes a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal, a second balanced terminal, a first filter part, and a second filter part. A phase of an electric signal transmitted from first unbalanced terminal to the first balanced terminal in the first filter part is different from a phase of an electric signal transmitted from the second unbalanced terminal to the first balanced terminal in the second filter part. A phase of an electric signal transmitted from the first unbalanced terminal to the second balanced terminal in the first filter part is different from a phase of an electric signal transmitted from the second unbalanced terminal to the second balanced terminal in the second filter part.

Abstract: A filter includes: a coupled multi-mode acoustic wave filter connected between an input terminal and an output terminal; a first inductor connected between the coupled multi-mode acoustic wave filter and a ground terminal; an acoustic wave resonator, one end of which is connected between the input terminal or the output terminal and the coupled multi-mode acoustic wave filter; and a second inductor connected between another end of the acoustic wave resonator and the ground terminal.

Abstract: A DMS filter has improved signal suppression in fly-back. At least two transformers of a first type are connected in parallel between a common node of the signal path and a ground connection/reference potential. A concentrated element is connected in the signal path of said transformers of the first type, so that the voltages present at the first transformers are different from each other.

Abstract: A filter includes: first series resonators and first parallel resonators that are connected in a ladder shape between an input terminal and an output terminal; a first inductor that is connected in parallel to at least one first series resonator; one or more second parallel resonators that are provided separately from the first parallel resonators, are connected between the input terminal and the output terminal, and have a resonance frequency and an anti-resonance frequency at frequencies lower than a passband formed by the first series resonators and the first parallel resonators; wherein an attenuation region is formed by a first attenuation pole formed by the at least one first series resonator and the first inductor and a second attenuation pole formed by a resonant response of the one or more second parallel resonators.

Abstract: A duplexer includes: a transmit filter that is connected between an antenna terminal and a transmit terminal and has a plurality of acoustic wave resonators; a receive filter that is connected between the antenna terminal and a receive terminal and has a plurality of acoustic wave resonators; and a delay line or a longitudinal coupling type resonator that is connected in parallel with at least one of the plurality of acoustic wave resonators of the transmit filter and the plurality of acoustic wave resonators of the receive filter and has at least two IDTs (Interdigital Transducers).

Abstract: A small-sized surface acoustic wave filter device having favorable filter characteristics includes a transmission-side surface acoustic wave filter chip including a ladder surface acoustic wave filter unit located on a piezoelectric substrate. The ladder surface acoustic wave filter unit includes a series arm connected between an input pad and an output pad and a plurality of resonators and including at least one first resonator connected to the input pad or the output pad. A die-attach surface is provided with an inductor connected to the first resonator. The inductor is arranged such that at least a portion thereof faces the first resonator and does not face any of the plurality of resonators and other than the first resonator.

Abstract: On a piezoelectric board, a SAW element has first to fifth IDT electrodes and reflector electrodes with first to fourth electrode-finger narrow-pitch portions N1-N4 being formed in the respective ones of adjoining portions of the respective first to fifth IDT electrodes. An unbalanced signal terminal and balanced signal terminals are connected to the SAW element. The electrode finger pitches of the first to fourth electrode-finger narrow-pitch portions N1-N4 are formed symmetrically with respect to the third, central IDT electrode in such a manner that the electrode finger pitch of the first electrode-finger narrow-pitch portion N1 is narrower than that of the second electrode-finger narrow-pitch portion N2, while the electrode finger pitch of the fourth electrode-finger narrow-pitch portion N4 is narrower than that of the third electrode-finger narrow-pitch portion N3.

Abstract: Disclosed embodiments include a surface acoustic wave device having electrode period, electrode width, and/or ratio of electrode width to electrode period varied in a prescribed manner.

Abstract: An acoustic wave device includes: a substrate; a dielectric film formed on the substrate; opposing comb-shaped electrodes located between the substrate and the dielectric film, each of the opposing comb-shaped electrodes including an electrode finger, wherein at least one of the substrate and the dielectric film is a piezoelectric substance, an upper surface of the dielectric film, which is located above a gap between a tip of an electrode finger of one of the opposing comb-shaped electrodes and the other of the opposing comb-shaped electrodes, is inclined against an upper surface of the substrate in an extension direction of the electrode finger, and an inclination angle of the upper surface of the dielectric film against the upper surface of the substrate is equal to or larger than 30° and equal to or smaller than 50°.

Abstract: An acoustic wave device includes: a multilayer structure that has plural surfaces which principal surfaces of plural layers provide; a chip including an acoustic wave filter and mounted on a first surface; a resin unit sealing the chip; a wiring pattern that is formed on a second surface and electrically connected to at least one of resonators; a ground pattern that is formed on the second surface along a part of the wiring pattern, and is away from the wiring pattern; and an external terminal that is formed on a third surface and electrically connected to the wiring pattern and the ground pattern, the third surface being disposed on an opposite side of the first surface with respect to the second surface; wherein a part of the wiring pattern that comes closest to the ground pattern is substantially formed in parallel with the ground pattern.

Abstract: The present invention is an acoustic wave device including first and second acoustic wave resonators. A first tilt angle that is an angle formed between a direction perpendicular to a direction in which electrode fingers of the first acoustic wave resonator extend and a direction along which the electrode fingers are arranged is different from a second tilt angle that is an angle formed between a direction perpendicular to a direction in which electrode fingers of the second acoustic wave resonator extend and a direction along which the electrode fingers are arranged.

Abstract: An SAW device includes: a piezoelectric substrate 1; a first and a second SAW elements 2, 3 having three or more odd-number IDT electrodes 4-9 and reflector electrodes 10-13 arranged on the piezoelectric substrate 1; lines 16 which cascade-connect the first and the second SAW elements 2, 3; a first unbalanced signal terminal 14 connected to the IDT electrodes 4, 6 arranged at the both ends of the first SAW elements 2; and a second unbalanced signal terminal 15 connected to the IDT electrodes 7, 9 arranged at the both ends of the second SAW element 3. In each of the first and the second SAW elements 2, 3, one bus bar electrode 17 of each of center IDT electrodes 5, 8 is split into two, and non-split bus bar electrodes 18, 19 of at least one center IDT electrode of the first and the second SAW elements 2, 3 are connected to a reference potential electrode and the lines 16 are made to be balanced signal lines.

Abstract: An elastic wave filter has first, second, and third IDT electrodes whose wiring electrodes are connected to unbalanced signal terminal; fourth IDT electrode disposed between the first and second IDT electrodes; fifth IDT electrode disposed between the second and third IDT electrodes; and first and second balanced signal terminals connected to the wiring electrodes of fourth and fifth IDT electrodes, respectively. The ground electrodes of the first through fifth IDT electrodes are connected to the ground. Signals in opposite phase and in phase with a signal input to unbalanced signal terminal are output from first and second balanced signal terminals, respectively. The wiring electrodes of second and third IDT electrodes are adjacent to the ground electrode of fifth IDT electrode. The wiring electrode of one of first and second IDT electrodes is adjacent to the wiring electrode of fourth IDT electrode. The ground electrode of the other is adjacent to the ground electrode of fourth IDT electrode.

Abstract: Disclosed is a surface acoustic wave device which has IDT electrodes arranged over a lithium tantalate piezoelectric substrate and is capable of suppressing propagation losses even at a high frequency band equal to or higher than 2 GHz as low as possible in order to utilize surface acoustic waves including LSAW. For this purpose, 45° to 46° rotated YX-cut lithium tantalate substrate is used as the piezoelectric substrate, a thickness of the IDT electrode is set to 7.5% ? to 8% ?, and a metallization ratio in electrode fingers of the IDT electrode is set to 0.55 to 0.65.

Abstract: The present invention relates to the field of acoustic wave devices, and particularly to that of transducers capable of operating at very high frequencies, from a few hundred MHz to several gigahertz, and its subject is more particularly an interface acoustic wave device including at least two substrates and a layer of ferroelectric material, the latter being contained between a first electrode and a second electrode and having first positive-polarization domains and second negative-polarization domains, the first and second domains being alternated, wherein the assembly constituted by the first electrode, the layer of ferroelectric material, and the second electrode is contained between a first substrate and a second substrate.

Abstract: In a boundary acoustic wave resonator, apodization weighting is performed on an IDT electrode so that an intersecting width decreases as a location moves outward in a boundary acoustic wave propagation direction. An inner side of a first busbar includes inclined portions that are disposed a predetermined distance from an envelope portion B1 on the side of the first busbar. An inner side of a second busbar includes inclined portions that are disposed a predetermined distance from an envelope portion on the side of second busbar. The sum of the numbers of electrode fingers and dummy electrodes that a straight line extending from the end of at least one of electrode fingers in the boundary acoustic wave propagation direction crosses before reaching the side of the first busbar or the side of the second busbar is equal to or greater than 5.

Abstract: To provide a receiving side filter of a duplexer and a duplexer capable of preventing a leakage of an electric field and a magnetic field to the outside. In a receiving side filter having a longitudinal mode resonator type filter including cross finger electrodes and reflectors respectively formed on a piezoelectric substrate and an unbalanced input signal path and balanced output ports respectively provided on an input side and on an output side of the longitudinal mode resonator type filter, and used on a receiving side of a duplexer, a shield electrode connected to a ground electrode side of the cross finger electrode is disposed to surround a periphery of the receiving side filter so that an electric field and a magnetic field leaked to the outside from the receiving side filter are short-circuited by the shield electrode.

Abstract: A boundary acoustic wave device includes a piezoelectric substrate having an upper surface in which grooves are provided, IDT electrodes which are at least partially embedded in the grooves in the upper surface of the piezoelectric substrate in a thickness direction of the IDT electrodes, and first and second dielectric layers stacked on the upper surface of the piezoelectric substrate. The second dielectric layer has an acoustic velocity greater than that of the first dielectric layer.

Abstract: A ladder acoustic wave filter device is constructed such that ripples in the pass band are suppressed, and insertion loss is small in both of a high frequency side portion and a low frequency side portion of the pass band. Apodization weighting is applied to a series-arm-side IDT electrode. Busbars of the series-arm-side IDT electrode are configured so that in an acoustic wave propagation direction, a distance in an overlap width direction between the busbars becomes shorter as the overlap width of electrode fingers becomes smaller. Each of a pair of comb-shaped electrodes of a parallel-arm-side IDT electrode further includes a plurality of dummy electrodes that extend from a busbar and are opposed to electrode fingers of the other comb-shaped electrode in the overlap width direction. The parallel-arm-side IDT electrode is a normal IDT electrode in which the overlap width is constant.

Abstract: Disclosed is a pass band type acoustic wave filter capable of obtaining an excellent attenuation characteristic in attenuation bands, in which an IDT electrode having a meander structure is used as at least one of the input-side electrode and the output-side electrode, and the attenuation band is provided over/under the pass band. An electrode having a meander structure in which a plurality of IDT blocks are connected to each other in series between the input port or the output port and the ground port is arranged as the input-side IDT electrode and the output-side IDT electrode, and the electrode finger between the neighboring IDT blocks is removed, so as to suppress excitation of an undesired acoustic wave.

Abstract: A surface acoustic wave device comprises a piezoelectric substrate (1), at least one inter-digital transducers (IDT) (2) provided on the piezoelectric substrate, at least one elongated electrode pad (4) electrically connected to the IDT, and at least one stud bump (5) disposed on the electrode pad such that an LC component of the surface acoustic wave device has a predetermined value.

Abstract: In an elastic-wave filter device that includes a band-pass filter and a band-eliminate filter connected to the band-pass filter, insertion loss in a pass band is significantly reduced and attenuation in a stop band is significantly increased. The elastic-wave filter device has a pass band and a stop band at frequencies higher than the pass band. The band-pass filter and the first band-eliminate filter are connected in series between an input terminal and an output terminal. A first parallel-arm resonator of the first band-eliminate filter includes a first resonance frequency in the stop band. A second parallel-arm resonator includes a second resonance frequency in the stop band, the second resonance frequency being higher than the first resonance frequency. An impedance value of the first parallel-arm resonator is larger than an impedance value of the second parallel-arm resonator.

Abstract: Provided are a photosensitive resin composition which is excellent in a moisture and heat resistance and provides a cured product thereof with a high elastic modulus at high temperature and which is excellent as well in a hollow structure holding property and a photosensitive film prepared by using the same, a forming method for a rib pattern, a hollow structure and a forming method for the same and an electronic component. In an electronic component having a hollow structure, a photosensitive resin composition is used as a rib material or a cover material for forming the hollow structure described above, and it is characterized by using a photosensitive resin composition containing (A) a photopolymerizable compound having at least one ethylenically unsaturated group and (B) a photopolymerization initiator and a photosensitive film obtained from the above photosensitive resin composition.

Abstract: An elastic wave filter device includes first and second inductance elements included in a laminated substrate and first and second elastic wave filter chips mounted on the laminated substrate by flip-chip bonding. The first and second inductance elements provided in the laminated substrate include first and second coil patterns, respectively, which are provided in a plane located at a certain height level in the laminated substrate. The second coil pattern is arranged in a region in which the first coil pattern is provided.

Abstract: Described herein are embodiments of transferring electromagnetic energy that includes providing a first electromagnetic resonator structure receiving energy from an external power supply, said first resonator structure having a first mode with a resonant frequency ?1, an intrinsic loss rate ?1, and a first Q-factor Q1=?1/(2?1), providing a second electromagnetic resonator structure being positioned distal from said first resonator structure and not electrically wired to the first resonator structure, said second resonator structure having a second mode with a resonant frequency ?2, an intrinsic loss rate ?2, and a second Q-factor Q2=?2/(2?2), and transferring electromagnetic energy from said first resonator structure to said second resonator structure over a distance D that may be smaller than each of the resonant wavelengths ?1 and ?2 corresponding to the resonant frequencies ?1 and ?2, respectively. The electromagnetic resonator structures may be designed to have Q1>100 and Q2>100.

Abstract: A method of adjustment on manufacturing of a monolithic oscillator including circuit elements and a BAW resonator, this method including the steps of: a) forming the circuit elements and the resonator and electrically connecting them; b) covering the resonator with a frequency adjustment layer; c) measuring the output frequency of the oscillator; d) modifying the thickness of the frequency adjustment layer to modify the output frequency of the oscillator.

Abstract: Described herein are embodiments of a source resonator optionally coupled to an energy source, and a second resonator, optionally coupled to an energy drain that may be located a distance from the source resonator. The source resonator and the second resonator may be coupled to provide ?/sqrt(?1?2)>0.2 via near-field wireless energy transfer among the source resonator and the second resonator over distances up to at least the characteristic size of a resonator.

Abstract: A communication device includes a communication circuit unit processing a high-frequency signal, a transmission path connected to the communication circuit, a ground, a coupling electrode supported so as to face the ground and to be separated by a height negligible with respect to a wavelength of the high-frequency signal, a resonating unit increasing a current flowing into the coupling electrode via the transmission path, and an extended section formed of a conductor disposed near a front of the coupling electrode with an angle ? formed relative to a direction of a microdipole being approximately 0 degree, the microdipole being formed of a line segment connecting a center of charges stored in the coupling electrode and a center of mirror-image charges stored in the ground, the conductor extended in a lateral direction approximately orthogonal to a propagating direction of an electric-field signal occurring from the front of the coupling electrode.

Abstract: An acoustic wave device includes: a support substrate composed of lithium tantalate in multi-polarization condition; an element substrate that is provided on an upper face of the support substrate and is composed of lithium tantalate, a lower face of the element substrate being jointed to the upper face of the support substrate; and a comb-like electrode that is provided on an upper face of the element substrate and excites an acoustic wave.

Abstract: A system exchanges energy wirelessly and includes a source configured to generate evanescent waves, in response to receiving the energy, on at least part of a surface of the source. The system also includes a sink configured to receive the energy wirelessly from the source via a coupling of the at least part of the evanescent waves and a load configured to receive the energy from the sink. The load and the sink are configured to move along the surface of the source such that the at least a part of the evanescent waves are coupled between the source and the sink within an energy transfer area.

Abstract: An acoustic wave duplexer includes a piezoelectric substrate, a first filter and a second filter whose center frequency is higher than that of the first filter, the first and second filters being provided on the piezoelectric substrate. The first filter is structured as a ladder type. A resonator positioned nearest to an antenna terminal out of series-arm resonators is designated as a first resonator. A pitch of a comb-shaped electrode structuring the first resonator is set such that a bulk wave emission frequency of the first resonator becomes higher than a passband of the second filter.

Abstract: A method of manufacturing a boundary acoustic wave device includes the steps of forming an electrode on a first medium layer, forming a second medium layer so as to cover the electrode on the first medium layer, and forming a sound absorbing layer on an external surface of the second medium layer. The sound absorbing layer has an acoustic velocity of transverse waves that is lower than an acoustic velocity of transverse waves of the second medium layer.

Abstract: A branching filter includes an antenna terminal, a transmission signal terminal, a reception signal terminal, a transmission filter element, and a reception filter element. At least one of the transmission filter element and the reception filter element includes a longitudinally coupled resonator filter element having first and second IDT electrodes arranged along a direction of propagation of an elastic wave. The first IDT electrode includes a first end connected to the antenna terminal. The second IDT electrode includes a first end connected to one of the transmission signal terminal and the reception signal terminal. The longitudinally coupled resonator filter element further includes an inductor connected in series between a second end of the first IDT electrode and a ground potential.

Abstract: A method of protecting a resonating sensor is described. The protected resonating sensor may include at least one passive ultrasonically excitable resonating sensor unit. Each sensor unit has one or more vibratable members having a resonating frequency that varies as a function of a physical variable in a measurement environment. The sensor is protected by forming one or more protective chambers defined between a compliant member and the vibratable member(s). A substantially non-compressible medium is disposed within the protective chamber(s). The compliant member has a first side that may be exposed to a measurement environment and a second side that may be exposed to the substantially non-compressible medium. The substantially non-compressible medium may be a liquid or gel and is in contact with the vibratable member(s). When the medium is a liquid, the chamber is sealed. When the medium is a gel, the chamber may be sealed or non-sealed.

Abstract: An elastic wave filter includes at least a piezoelectric substrate and a longitudinally coupled resonator-type elastic wave filter unit provided on the piezoelectric substrate. The longitudinally coupled resonator-type elastic wave filter unit includes first to fifth IDTs and first and second reflectors arranged on either side of the first to fifth IDTs. The third IDT includes first and second divided comb-shaped electrodes. The second and fourth IDTs are connected to an unbalanced signal terminal, the first IDT and the first divided comb-shaped electrode of the third IDT are connected to a first balanced signal terminal, and the fifth IDT and the second divided comb-shaped electrode of the third IDT are connected to a second balanced signal terminal. The first and fifth IDTs each have a constant electrode finger pitch, and the electrode finger pitch of the first IDT is less than that of the fifth IDT.

Abstract: Disclosed is a miniaturized duplexer having a good isolation characteristic. A duplexer having a high band side filter and a low band side filter that are each formed in a ladder-type filter provided on a common piezoelectric substrate is provided with a first elastic wave resonator to be included in one of these filters, a second elastic wave resonator to be included in the other of the filters, and a first additional grating reflector provided between these resonators to reflect an elastic wave leaked from a grating reflector of the first elastic wave resonator, and in which an additional grating reflector is not provided on a side opposite to the second elastic wave resonator in the first elastic wave resonator.

Abstract: A ladder filter including a series arm resonator and a parallel arm resonator disposed on the same common piezoelectric substrate achieves improved miniaturization. The ladder filter includes series arm resonators and parallel arm resonators, which include elastic wave resonators, and are disposed on the same common piezoelectric substrate, at least one parallel arm resonator of the series arm resonators and the parallel arm resonators includes a first resonator and a second resonator electrically connected in parallel to each other, and the first resonator and the second resonator are arranged in parallel or substantially in parallel in a direction perpendicular or substantially perpendicular to an elastic wave propagation direction, on one side outside one series arm resonator of remaining resonators in the elastic wave propagation direction thereof.

Abstract: A polar SAW (Surface Acoustic Wave) filter includes a band-pass ladder type SAW filter having a SAW resonator. A two-terminal pair circuit is serially connected to the band-pass ladder type SAW filter and includes a plurality of inductors. The polar SAW filter has attenuation poles in each of the higher-frequency and lower-frequency attenuation ranges of a pass band.