Abstract: A saw filter of the invention has a piezoelectric substrate (11), plural numbers of IDT electrodes (12,13) arranged on a surface of the piezoelectric substrate (11) as well as on a first surface acoustic wave propagation path, reflector electrodes (14,15) arranged at least at both ends of a first electrode pattern formed including the plural IDT electrodes (12,13), one or more IDT electrodes (16) arranged on the surface of the piezoelectric substrate (11) as well as on a second surface acoustic wave propagation path which is different from the first surface acoustic wave propagation path and reflector electrodes arranged at least at both sides of a second electrode pattern formed including the IDT electrode (16), in which the IDT electrodes (12,13) on the first surface acoustic wave propagation path are electrically connected in series by connecting wirings (19) and the IDT electrode (16) on the second surface acoustic wave propagation path is connected between the connecting wirings (19) and the ground (20),

Abstract: A branching filter package has a SAW filter chip housing area which houses a piezo electric base, on which a transmitting SAW filter and a receiving SAW filter having a different frequency passing band with each other, are formed, and an impedance matching circuit and a branching circuit for the transmitting SAW filter and the receiving SAW filter.

Abstract: A series piezoelectric resonator 11 is connected in series between an input terminal 15a and an output terminal 15b. A first electrode of a parallel piezoelectric resonator 12a is connected to a connection point between the input terminal 15a and the series piezoelectric resonator 11, and a second electrode of the parallel piezoelectric resonator 12a is connected to a first terminal of an inductor 13a. A first electrode of a parallel piezoelectric resonator 12b is connected to a connection point between the series piezoelectric resonator 11 and the output terminal 15b, and a second electrode of the parallel piezoelectric resonator 12b is connected to a first terminal of an inductor 13b. Second terminals of the inductors 13a and 13b are grounded. An additional piezoelectric resonator 14 is connected between the second electrode of the parallel piezoelectric resonator 12a and the second electrode of the parallel piezoelectric resonator 12b.

Abstract: In a balanced type surface acoustic wave filter, a first longitudinally coupled resonator-type surface acoustic wave filter portion connected to an unbalanced input terminal and a second longitudinally coupled resonator-type surface acoustic wave filter portion connected to first and second balanced input terminals are two-stage cascade connected. In the first longitudinally coupled resonator-type surface acoustic wave filter portion, in a portion in which first and second IDTs are adjacent to each other and a portion in which second and third IDTs are adjacent to each other, weighting is performed on a plurality of electrode fingers including the outermost electrode finger closest to the adjacent IDT, in at least one of the adjacent IDTs.

Abstract: A method for manufacturing a surface acoustic wave device includes the steps of forming an IDT electrode, a first wiring pattern, and a third wiring pattern on a piezoelectric substrate, forming an insulating film covering the IDT electrode and the wiring patterns, forming a photosensitive resin film, obtaining the photosensitive resin film, and forming a second wiring pattern on an insulating layer composed of the insulating film and the photosensitive resin film laminated on the insulating film so that the second wiring pattern three-dimensionally crosses the first wiring pattern.

Abstract: A duplexer that includes: a transmission filter and a reception filter that are connected to a common terminal; and a reactance circuit that is connected to at least one of the transmission filter and the reception filter. The reactance circuit includes an insulating substrate, lumped-constant inductors, and at least one capacitor. The lumped-constant inductors and the capacitor are formed directly on the surface of the insulating substrate.

Abstract: A miniaturised half-wave balun comprises a single-ended I/O port comprising a first signal carrying terminal for connection to a source impedance and a differential I/O port comprising second and third signal carrying terminals for connection to a load impedance. First and second transmission line sections of equal length and characteristic impedance are connected together at a common end and at opposite ends to the second and third terminals. The first signal carrying terminal is coupled to the first transmission line section. The combined length of the first and second transmission line sections is substantially less than one half of the wavelength of an RF signal at the operating frequency. First and second loading shunt capacitors are connected to respective first and second transmission line sections. A shunt capacitive element is connected at the common end of the transmission line sections.

Abstract: In a longitudinally-coupled-resonator-type elastic wave filter device, at least one of two IDTs which are adjacent to each other is provided with a dummy electrode for series weighting in a portion in which the IDTs are adjacent to each other, and at least one of series-weighted portions includes at least one of metallization ratio reducing portion in a first acoustic track and metallization ratio increasing portion in a second acoustic track so as to reduce the difference between the metallization ratio of the first acoustic track passing through a connecting portion of the dummy electrode and the metallization ratio of each of second and third acoustic tracks each placed on either side of the first acoustic track in the direction of propagation of an elastic wave.

Abstract: A surface acoustic wave (SAW) filter includes a piezoelectric substrate, and acoustic tracks on the piezoelectric substrate. The acoustic tracks are adjacent and electrically interconnected. The acoustic tracks include electro-acoustic transducers. The electro-acoustic transducers include an input transducer and an output transducer. The SAW filter also includes a shielding structure that is metallic and that is connected to ground. The shielding structure is between the acoustic tracks. The shielding structure shields a first electro-acoustic transducer in a first acoustic track from a second electro-acoustic transducer in a second acoustic track.

Abstract: An acoustic wave sensor assembly includes piezoelectric material, a first acoustic wave resonator element structure mounted on the piezoelectric material for interacting with an electrical signal, the acoustic wave resonator element structure being operable to interact with an acoustic wave propagating within the piezoelectric material to produce a first frequency response. Further acoustic wave resonator element structures are mounted on the piezoelectric material for interacting with electrical signals, the further acoustic wave resonator element structures being operable to interact with further acoustic waves propagating within the piezoelectric material to produce subsequent frequency responses. The first acoustic wave resonator element structure and further acoustic wave resonator element structures are combined to form a ladder or lattice filter network to produce an overall frequency response.

Abstract: A surface acoustic wave device having a three-layered structure of sealing resin for sealing a mounting substrate and a surface acoustic wave element in which the elastic modulus of resin of the intermediate layer is higher than that of resin of the outermost layer and the elastic modulus of resin of the innermost layer is lower than that of resin of the outermost layer. The three-layered structure of the sealing resin suppresses crush of a bump when a pressure is applied from the outside and reduces stress applied to the bump due to the change in temperature.

Abstract: In an elastic wave device including an input side electrode and an output side electrode being a resonant single-phase unidirectional transducers (RSPUDT) provided with respective pairs of bus bars opposing to each other on a piezoelectric substrate and a number of excitation electrode fingers extending in a comb-teeth shape so as to respectively cross each other from the respective bus bars, the elastic waves are repeatedly reflected and amplified between the central part of the input side electrode and the central part of the output side electrode along the direction of extension of the respective bus bars by the excitation electrode fingers of the input side electrode and the output side excitation electrode, the elastic wave device includes a damper at least on either one of the input side bus bar or the output side bus bar in an area between the central part of the input side electrode in the direction of movement of the elastic waves and the central part of the output side electrode in the direction of

Abstract: An elastic boundary wave device includes a LiNbO3 substrate, an electrode exciting an elastic wave and provided on the substrate, and a silicon oxide film provided on the substrate to cover the electrode, and parameters of the elastic boundary wave device have any one of ranges, where “?” is a rotation Y cut angle of the substrate, “a” is a ratio of copper density with respect to a density of a material used as the electrode, “?” is a wavelength of the elastic wave excited by the electrode, “h” is a film thickness of the electrode, “H” is a thickness of the silicon oxide film.

Abstract: A transducer includes an acoustic track in which an acoustic wave can be propagated, the acoustic track having a transversal fundamental mode, the acoustic track being subdivided in a transversal direction into an excitation area and two peripheral areas. The transducer also includes a first outside area and a second outside area bordering the acoustic track such that the acoustic track is arranged in the transversal direction between the first and second outside area. The transducer also includes peripheral areas configured such that the longitudinal phase velocity vRB of the acoustic wave in the respective peripheral area is greater than the longitudinal phase velocity vMB of the wave in the excitation area.

Abstract: An elastic wave filter includes two longitudinally coupled resonator type elastic wave filter elements that are cascade connected with each other, each longitudinally coupled resonator type elastic wave filter element including three IDTs (interdigital transducers) arranged on a piezoelectric substrate in a transmitting direction of an elastic wave. In at least one of the longitudinally coupled resonator type elastic wave filter elements, electrode fingers of the IDTs that are cascade connected are arranged at a pitch that is smaller than a pitch of electrode fingers of the remaining IDT. The adverse effect of a parasitic capacitance in cascade connected wires disposed between the longitudinally coupled resonator type elastic wave filter elements is reduced so as to improve impedance matching of a cascade connected portion and to improve the VSWR characteristics of input-output terminals of the elastic wave filter.

Abstract: In an acoustic wave resonator, an IDT electrode is provided on a piezoelectric substrate. The IDT electrode is apodization-weighted such that a plurality of maximum values of cross widths are provided in acoustic wave propagation directions. Alternatively, in apodization weighting, weighting is applied such that at least one of a pair of envelopes located at outer side portions of the IDT electrode in directions substantially perpendicular to acoustic wave propagation directions includes a plurality of angled envelope portions angled from a central portion of the IDT electrode toward an outer side portion of the IDT electrode in a direction substantially perpendicular to the acoustic wave propagation directions.

Abstract: An acoustic boundary wave device includes a first medium having piezoelectricity, electrodes that are provided on the first medium and excite acoustic waves, a second medium made of a material different from the first medium and provided on the first medium so as to cover the electrodes, and a third medium that has a heat conductivity higher than that of the second medium and is provided so as to contact an upper surface of the second medium and at least a part of side surfaces of the second medium.

Abstract: A piezoelectric substance has a substrate, an electrode formed on the substrate, and a piezoelectric film formed on the electrode. The piezoelectric film is formed of crystals having a main phase of (NaxKyLiz)NbO3 (0<x<1, 0<y<1, 0?z?0.1, x+y+z=1). The piezoelectric film is a polycrystalline thin film preferentially oriented to either or both of <001> and <110> crystalline axes in the direction normal to the substrate surface, and the axes of its crystals oriented to each crystalline axis are also formed in the same direction in the in-plane direction of the substrate.

Abstract: A radio communication method and system for transmitting multiple-user digital data information in a Code Division Multiple Access (CDMA) format over multipath and mutual-interfering channels to a receiving terminal with diversity antennas and equalization signal processing. At the receiving terminal, diversity antenna signals are grouped into time blocks and replicas are generated of the user-unique CDMA sequence signals for a set of K mutually interfering users. Within each time block the multiuser channel is estimated, equalization parameters are calculated, and decision-feedback equalization is used to produce multiuser estimates associated with a subset ? of the K users. These estimates are deinterleaved and error-correction decoded to recover transmitted digital data information for the subset of ? users.

Abstract: A surface acoustic wave device has a piezoelectric substrate and an IDT formed on the piezoelectric substrate, and uses an excited wave as an SH wave. The piezoelectric substrate is a quartz plate in which a cut angle ? of a rotated Y-cut quartz substrate is set in the range of ?65°????51° in a counter-clockwise direction from a crystal Z-axis and the propagation direction of a surface acoustic wave is set in the range (90°±5°) with respect to a crystal X-axis. The IDT is made of Ta or an alloyed metal containing Ta as the main component.

Abstract: An apparatus including a piezoelectric substrate having at least one transducer electrode structure. The structure having a metallization formed by one or more metals with a mean specific density that is at least 50% higher than that of aluminum. The structure having a compensation layer that is applied fully or partially over the metallization. The compensation layer is of a material having a temperature dependence of elastic constants that counteracts the temperature coefficient of frequency of the substrate. The compensation layer has a thickness that is less than 15% of an acoustic wavelength of a wave capable of propagation in the structure.

Abstract: A surface acoustic wave device includes a surface acoustic wave (SAW) chip and a cover that are bonded in a body by bonding a metal bonding portion of the SAW chip and a metal bonding portion of the cover and bonding extraction electrodes of the SAW chip and connection electrodes of the cover so as to hermetically seal IDT electrodes disposed on a main surface of a piezoelectric substrate of the SAW chip within a space defined between the SAW chip and the cover. The IDT electrodes and external electrodes on an upper surface of an insulating substrate of the cover are electrically connected to each other through conductive materials formed in through-holes.

Abstract: An acoustic wave filter includes: a ladder filter that has acoustic wave resonators connected in series and parallel arms; an inductor that is provided between a ground and at least one of the parallel-arm resonators in the ladder filter; and a resonance circuit that is provided in parallel with the inductor, and is located between the ground and the parallel-arm resonators in the ladder filter. In this acoustic wave filter, the resonance frequency of the resonance circuit is expressed as: 2f0?150 MHz<fr<2f0+150 MHz or 3f0?150 MHz<fr<3f0+150 MHz, where fr represents the resonance frequency, and f0 represents the passband frequency of the ladder filter.

Abstract: In an elastic wave acoustic device, input ends of first to third longitudinally coupled resonator surface acoustic wave filters are connected to an unbalanced signal terminal, the output end of the first longitudinally coupled resonator surface acoustic wave filter, and a first IDT defining a first output terminal of the second longitudinally coupled resonator surface acoustic wave filter are connected to a first balanced signal terminal, the output end of the third longitudinally coupled resonator surface acoustic wave filter, and a third IDT defining a second output terminal of the second longitudinally coupled resonator surface acoustic wave filter are connected to a second balanced signal terminal, and the phase of an output signal to an input signal of the first longitudinally coupled resonator surface acoustic wave filter differs by about 180 degrees from the phase of an output signal to an input signal of the third longitudinally coupled resonator surface acoustic wave filter.

Abstract: A boundary acoustic wave device includes a first medium, a second medium, and an IDT electrode disposed at an interface between the first medium and the second medium, the IDT electrode having an Au layer defining a main electrode layer, wherein a Ni layer is laminated so as to contact at least one surface of the Au layer, and a portion of Ni defining the Ni layer is diffused from the Ni layer side surface of the Au layer toward the inside of the Au layer.

Abstract: A SAW device D1 according to the present invention comprises a ladder-type SAW device T1 for transmission and a ladder-type SAW device R2 for receiving on a main surface of a piezoelectric substrate. The ratio (LT/PT) of the width LT of electrode fingers to the pitch PT between the electrode fingers in a SAW resonator S1 in the ladder-type SAW device T1 for transmission is made lower than the ratio (LR/PR) of the width LR of electrode fingers to the pitch PR between the electrode fingers in a SAW resonator S2 in the ladder-type SAW device R2 for receiving. As a result, the SAW device D1 has a low loss within a band and has steep attenuation characteristics outside the band, and is miniaturized.

Abstract: A surface acoustic wave (SAW) resonator, including: a first interdigital transducer composed of a pair of interdigital electrodes provided in a propagation direction of a surface acoustic wave; a second interdigital transducer composed of a pair of interdigital electrodes provided in parallel to the first interdigital transducer; and a switch that alternately switches the pair of interdigital electrodes of the first interdigital transducer and the pair of interdigital electrodes of the second interdigital transducer; wherein 7??B?33? where ? is a wavelength of a surface acoustic wave, and B is an addition of a width a1 of an engaged section of electrode fingers of the first interdigital transducer, a width a2 of an engaged section of electrode fingers of the second interdigital transducer, and a distance b between the engaged sections of both interdigital transducers.

Abstract: A surface acoustic wave apparatus comprises a piezoelectric substrate 17 on the bottom face of which IDT electrodes 3 and 4 and an annular ground electrode 6 which encloses the IDT electrodes 3 and 4 and is connected to the IDT electrode 3, and a base substrate on the top face of which an annular ground conductor 7 is formed and which has an internal ground conductor layer 10a and a bottom face ground conductor layer 11a connected to the annular ground conductor 7 and an internal ground conductor layer 10b and a bottom face ground conductor layer 11b connected to the IDT electrode 4. A first ground conductor composed of the internal ground conductor layer 10a and the bottom face ground conductor layer 11a is electrically separated from a second ground conductor composed of the internal ground conductor layer 10b and the bottom face ground conductor layer 11b. The apparatus has an excellent out-of-band attenuation characteristic.

Abstract: A SAW ladder filter includes grating pads extending from opposing bus bars and interdigital transducer electrodes extending from the grating pads for defining an acoustic aperture. The metalization ratio for the grating pads is greater than that for the interdigital transducer electrodes. Reflector electrodes are disposed on opposing longitudinal sides of the interdigital transducer electrodes. Operation of the filter results in a velocity of the SAW along the grating pads slower than a SAW velocity along the plurality of interdigital transducer electrodes, thus producing a wave guiding effect for optimizing SAW propagation within the acoustic aperture. The grating pads may be longitudinally offset from cooperating interdigital transducer electrodes using minor bus bars.

Abstract: In a fitting region for a SAW filter which includes langasite as its piezoelectric element, there are included an input side terminal electrode and an output side terminal electrode which are connected to an input terminal and to an output terminal of the SAW filter. To each of the terminal electrodes, at a position which is separated by just a predetermined distance from the fitting region of the SAW filter, there is connected a micro strip line which extends in mutually opposite directions along a direction which is parallel to the transmission direction of a frequency signal within the SAW filter. A slit is provided in the fitting region of the SAW filter and extends in a direction which intersects the transmission direction of the frequency signal within the SAW filter. A plurality of through holes are provided in the printed substrate and electrically connect together its surface and its rear surface which is grounded.

Abstract: A surface acoustic wave device having a three-layered structure of sealing resin for sealing a mounting substrate and a surface acoustic wave element in which the elastic modulus of resin of the intermediate layer is higher than that of resin of the outermost layer and the elastic modulus of resin of the innermost layer is lower than that of resin of the outermost layer. The three-layered structure of the sealing resin suppresses crush of a bump when a pressure is applied from the outside and reduces stress applied to the bump due to the change in temperature.

Abstract: One of plurality of transmission terminals connected to a transmission filter and a receiving terminal connected to a receiving filter is a balanced type terminal, and another is an unbalanced type terminal. The transmission filter and the receiving filter includes surface acoustic wave resonators or film bulk acoustic resonators. The balanced type terminal is connected to a longitudinal mode coupled surface acoustic wave filter.

Abstract: Switches having an in situ grown carbon nanotube as an element thereof, and methods of fabricating such switches. A carbon nanotube is grown in situ in mechanical connection with a conductive substrate, such as a heavily doped silicon wafer or an SOI wafer. The carbon nanotube is electrically connected at one location to a terminal. At another location of the carbon nanotube there is situated a pull electrode that can be used to elecrostatically displace the carbon nanotube so that it selectively makes contact with either the pull electrode or with a contact electrode. Connection to the pull electrode is sufficient to operate the device as a simple switch, while connection to a contact electrode is useful to operate the device in a manner analogous to a relay. In various embodiments, the devices disclosed are useful as at least switches for various signals, multi-state memory, computational devices, and multiplexers.

Abstract: A piezoelectric substrate is joined to a cover with a support layer disposed therebetween and with a space maintained therebetween. A transmission surface acoustic wave filter and a reception surface acoustic wave filter are disposed on a major surface of the piezoelectric substrate adjacent to the cover and inside the support layer. External electrodes are provided on the side of the cover opposite to the side facing the piezoelectric substrate. The external electrodes include an antenna terminal electrically connected to the transmission surface acoustic wave filter and the reception surface acoustic wave filter, a transmission input terminal electrically connected to the transmission surface acoustic wave filter, and a reception output terminal electrically connected to the reception surface acoustic wave filter. A portion of an interconnection line that electrically connects the reception surface acoustic wave filter to the antenna terminal is disposed on the cover.

Abstract: An RF switching circuit that incorporates a film bulk acoustic resonator (FBAR) device and one or more capacitors that are used to vary the capacitance of the FBAR device to change the frequency range that is blocked by the FBAR device. When the RF switching circuit is in a first switching state, a first set of RF signals in a first frequency range is blocked by the RF switching circuit while RF signals of other frequencies are passed by the RF switching circuit. When the RF switching circuit is in a second switching state, a second set of RF signals in a second frequency range is blocked by the RF switching circuit while RF signals of other frequencies are passed by the RF switching circuit.

Abstract: A method for manufacturing a surface acoustic wave filter device includes a step of forming grooves in one principal surface of a piezoelectric substrate, a step of embedding a metallic film in the grooves to form IDT electrodes, a step of performing a process of removing a portion of the piezoelectric substrate from the one principal surface of the piezoelectric substrate, thereby forming a recessed portion including the bottom surface in which the IDT electrodes are embedded, and a step of bonding a cover member to the piezoelectric substrate.

Abstract: A band-stop filter is described herein. The band-stop filter includes a piezoelectric substrate and a plurality of surface wave element (SAW) impedance elements on the substrate. The band-stop filter also includes at least one series branch comprising at least one series resonator having a finger period, and a plurality of parallel branches connected electrically in parallel with the series branch, each parallel branch including at least one parallel impedance element comprising an interdigital transducer and having a finger period. The average finger period of the at least one series resonator is greater than the average finger period of the at least one parallel impedance element.

Abstract: An apparatus in one example comprises a piezoelectric layer, an input transducer, an output transducer, and at least one electrode set. The input transducer is configured to convert an input signal from an input source to a surface acoustic wave and send the surface acoustic wave from an input portion of the piezoelectric layer to an output portion of the piezoelectric layer. The input transducer comprises a set of input passbands. The output transducer is configured to receive the surface acoustic wave from the output portion of the piezoelectric layer. The output transducer comprises a set of output passbands. The at least one electrode set is configured to apply at least one voltage bias to at least one portion of the piezoelectric layer to create an electric field that controls an acoustic velocity of the surface acoustic wave through the at least one portion of the piezoelectric layer.

Abstract: A longitudinally-coupled-resonator surface acoustic wave filter device has a sufficient pass-band width, in which a large attenuation in a stop band near the low-frequency side of a pass band and sharp filter characteristics, and low insertion loss in the pass band are achieved. The filter device is a five-IDT longitudinally-coupled-resonator acoustic wave filter device including a first IDT, second and third IDTs arranged on either side of the first IDT in a direction of propagation of surface waves, and fourth and fifth outermost IDTs in the direction of propagation of surface waves, wherein when the first IDT has the number of electrode fingers N1 and an electrode finger pitch P1, the second and third IDTs have the number of electrode fingers N2 and an electrode finger pitch P2, and the fourth and fifth IDTs have the number of electrode fingers N3 and an electrode finger pitch P3, a relationship of N1<N2, N1<N3, P1<P2, and P1<P3 is satisfied.

Abstract: A programmable surface acoustic wave filter and methods thereof including a piezoelectric substrate, a ground electrode formed in a comb structure on the piezoelectric substrate, a plurality of output electrodes formed in comb structures on the piezoelectric substrate and alternately disposed together with the ground electrode, and a switching unit performing a switching operation so as to selectively transmit output signals output from the plurality of output electrodes to an output node. As a result, a filtering characteristic of the programmable surface acoustic wave filter can be programmed in a desired format.

Abstract: A SAW chip (11) where ones are balanced signal terminals and the others are unbalanced signal terminals is mounted on a mounting board (12) in a flip chip manner, and the mounting board (12) and a surface of the SAW chip are covered with resin (19). At that time, grounds of first and second SAW filters (1, 2) in the SAW chip (11) are connected together and an annular pattern (14) is formed so as to surround a signal pattern of the SAW chip (11) on the mounting board (12) on which the SAW chip (11) is mounted, and the annular electrode (14) is connected to a ground pattern.

Abstract: A component includes a first filter configured to work with acoustic waves. The first filter includes a first sub-filter on a first chip and a second sub-filter on a second chip separate from the first chip. The first filter if a different type of filter, has a different layer structure, or has a different layer thicknesses for at least one layer in comparison to the second filter.

Abstract: A method is provided that includes providing a mold on a temporary substrate, e.g., a sapphire substrate. Next, a material such as PZT paste is deposited into the mold. Then, the mold is removed to obtain elements formed by the mold. The formed elements will then be sintered. After sintering, electrode deposition is optionally performed. The sintered elements are then bonded to a final target substrate and released from the temporary substrate through laser liftoff. Further, electrodes may also be optionally deposited at this point.

Abstract: A filter device substrate 1 of the present invention is formed by stacking a plurality of ceramic layers 12, 14, and includes a filter chip mounting portion for mounting a transmission filter chip 2 and a reception filter chip 3. Arranged on a surface of one ceramic layer 12 are a signal input pad 73, a signal output pad 7, a signal input side ground pattern 44 and a signal output side ground pattern 43 for connecting a signal input terminal C, a signal output terminal D, a signal input side ground terminal G and a signal output side ground terminal G, respectively, of the reception filter chip 3. The signal input side ground pattern 44 and the signal output side ground pattern 43 are connected to each other by a connection wiring pattern 45 on the surface of the one ceramic layer 12.

Abstract: An acoustic wave filter device includes a piezoelectric substrate and a longitudinally coupled resonator surface acoustic wave filter unit provided on the piezoelectric substrate. The surface acoustic wave filter unit includes first to fifth IDTs arranged in a surface wave propagation direction. The first, third, and fifth IDTs are connected to an unbalanced terminal, while the second and fourth IDTs are connected to first and second balanced terminals, respectively. The second IDT includes first and second sub-IDT portions obtained by dividing the second IDT and arranged in a crossing width direction, and the fourth IDT includes first and second sub-IDT portions obtained by dividing the fourth IDT and arranged in the crossing width direction. The first and second sub-IDT portions are connected in series. The first and second sub-IDT portions are also connected in series.

Abstract: A balance filter includes a first filter having first multimode surface acoustic wave (SAW) filters connected in parallel, a second filter that is connected to the first filter and includes a second multimode SAW filter, a first terminal connected to the first filter, and second terminals connected to the second filters. An input terminal of the balance filter is one of the first and second terminals, and an output terminal thereof is the other. Electric signals transmitted from the first to second filters or vice versa are in opposite phase. Electric signals are input or output via the second terminals in opposite phase.

Abstract: A SAW filter device includes a SAW filter chip in which one-port surface acoustic wave resonators each including an IDT made of Al or an Al alloy, are provided on a ?-rotated Y-cut X-propagation LiNbO3 substrate. The cutting angle ? of the ?-rotated Y-cut X-propagation LiNbO3 substrate is in the range between about 50° and about 55°. The normalized film thickness of the IDT 100h/? (%) (h denotes the thickness of the IDT and ? denotes the wavelength of a surface acoustic wave) is in the range between about 2% and about 4%. The duty ratio of the IDT is equal to or less than about 0.4.

Abstract: In a longitudinally coupled resonator SAW filter apparatus, one end of each N first longitudinally coupled resonator SAW filter, where N is an integer equal to or greater than 2, is connected in parallel to an unbalanced signal terminal, the first N longitudinally coupled resonator SAW filters are connected in a cascade arrangement to M second longitudinally coupled resonator SAW filters, where M is an integer equal to or greater than 1, the M second longitudinally coupled resonator SAW filter are connected to first and second balanced signal terminals, and N and M are selected such that N>M.

Abstract: In a surface acoustic wave device, a plurality of grooves are provided on a piezoelectric substrate, an electrode film defining an IDT electrode is formed by filling an electrode material in the grooves, an insulator layer, such as a SiO2 film, is arranged so as to cover the piezoelectric substrate and the electrode film formed in the grooves, and the surface of the insulator layer is flattened.

Abstract: A surface acoustic wave device includes a piezoelectric substrate that does not restore the pyroelectric effect, and a method for manufacturing the same. A surface acoustic wave element housed in a package includes a piezoelectric substrate having a specific resistance in the range of about 1.0×107 ?·cm to about 1.0×1013 ?·cm. Pads are electrically connected to an external electrode with a solder. The space between the package and a cap of the package is sealed with a sealing material. At least one of the solder and the sealing material has a melting point of about 300° C. or less.