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.

Abstract: In a balanced-type surface acoustic wave filter, IDTs in the center of each of first and second longitudinally coupled resonator type surface acoustic wave filter sections are connected to an unbalanced input terminal, first and third IDT sections on both the sides of the center IDT are connected to first and second balanced output terminals, respectively, the first and third IDTs have narrow pitch electrode finger sections N, and when an electrode finger pitch of the narrow pitch electrode finger section of the second IDT is P1, an electrode finger pitch of the narrow pitch electrode finger section of the first and third IDTs is P2, the number of electrode fingers of the second IDT except for the narrow pitch electrode finger section of the IDT is K1, and the number of electrode fingers of the first and third IDT except for the narrow pitch electrode finger section is K2, P1>P2 and 1.12?K1/K2?1.65 are satisfied.

Abstract: A multimode type SAW filter includes a piezoelectric substrate, and IDT groups formed on the piezoelectric substrate, the IDT groups each having multiple IDTs connected in series in which an input/output electrode and a ground electrode are coupled via a floating conductor. Adjacent electrode fingers between adjacent IDTs among the multiple IDTs of the IDT groups include a first electrode finger connected to the floating conductor in one of the IDT groups and a second electrode finger connected to one of the input/output electrode and the ground electrode in another one of the IDT groups.

Abstract: Manufacturing a piezoelectric vibration device, includes: forming a bonding electrode on a part of a piezoelectric substrate to which a cover makes contact; forming a part defining a through hole to the cover so that a profile of an edge of an opening of the through hole at a first surface of the cover is positioned inside an outer shape of the taking out electrode in a plan view when the cover and the piezoelectric substrate are overlapped; forming a first glass film on the first surface of the cover; forming a second glass film on the first surface of the cover; bonding the first glass film to the taking out electrode as well as the second glass film to the bonding electrode by generating an electric field; and cutting an electrical coupling between the taking out electrode and the bonding electrode after step (e).

Abstract: An electronic circuit comprises a resonator meant to be integrated into a semiconductor product including a resonator having first and second resonant frequencies. The electronic circuit comprises: a first inductive partner element for canceling out said second resonant frequency, said partner element having a quality coefficient QI (f) having a first value in a predetermined frequency band and a second value outside said frequency band; a second capacitive partner element for adjusting tuning of said resonator to said first frequency.

Abstract: An acoustic wave device comprising a piezoelectric layer on an omnidirectional acoustic mirror and excitation and/or reception means on a surface of said piezoelectric layer, capable of exciting waves in a band gap of the acoustic mirror.

Abstract: A surface acoustic wave filter includes an antenna terminal, a transmitting filter and a variable branching line both of which are coupled to the antenna terminal and a receiving filter coupled to the variable branching line. The transmitting filter has a first end series-arm SAW resonator, a second end series-arm SAW resonator, a middle series-arm SAW resonator coupled between the first and second end series-arm SAW resonators and parallel-arm SAW resonators. Each of the first and second end series-arm SAW resonator has a first resonance frequency. The middle series-arm SAW resonator has a second resonance frequency that is higher than the first resonance frequency.

Abstract: A method of manufacturing a surface acoustic wave device formed in one chip and including over a semiconductor substrate at least an IC region and a surface acoustic wave element region that are horizontally disposed, the method including: forming in the IC region over the semiconductor substrate a semiconductor element layer that includes a semiconductor element and an insulation layer covering the semiconductor element and being deposited also in the surface acoustic wave element region; forming over the semiconductor element layer a wire layer that includes a plurality of wires coupled to the semiconductor element and a wire insulating film deposited over the plurality of wires to provide insulation among the wires, the wire insulating film being deposited also over the insulation layer in the surface acoustic wave element region; forming an interlayer insulating film having a flattened surface on the wire insulating film in the IC region and the surface acoustic wave element region; forming a piezoelectri

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 radio filter has a band pass filter for passing a desired band of signal frequencies and a band stop filter for reducing the passing of a band of undesired signal frequencies. The filter comprises an input terminal, an output terminal, and a filter having a multiple of transmission lines arranged between said input and output terminal which filters input signals through said input terminal to pass signals of a given frequency band. A ground is connected to said transmission lines at first ends of said multiple of transmission lines and acoustic impedance elements are connected between said ground layer and second ends of said multiple transmission lines for providing a stop band filter function of the input signals, and whereby the input signal after band pass filtering and stop band filtering is provided at said output terminal.

Abstract: A surface acoustic wave apparatus includes an input terminal, an output terminal, a plurality of acoustically coupled interdigital transducers (IDT), and a phase rotating element (line or inductor) connected in parallel with one or more IDT's. The acoustically coupled IDT's are connected in series between the input and output terminals. Alternatively, the acoustically coupled IDT's may include a series IDT to which the phase rotating element is connected and which is connected in series between the input and output terminals, and a branch IDT acoustically coupled to the series IDT, and disposed on a transmission path which branches from a transmission path between the input and output terminals to a reference potential. Among the plurality of IDT's, ?a??b is established, where ?a represents an electrode finger pitch of the IDT to which the phase rotating element is connected, and ?b represents an electrode finger pitch of the IDT to which no phase rotating element is connected.

Abstract: An elastic boundary wave device includes an IDT including laminated conductor layers disposed between a first medium and a second medium, wherein a plane that divides the IDT in half in the thickness direction defines an interface, the energy of an elastic boundary wave present on the side of the first medium of the interface is denoted as E1, and the energy of an elastic boundary wave present on the side of the second medium of the interface is denoted as E2, and wherein if the IDT included only a conductor having the highest density among the laminated conductor layers of the IDT, when the energy of an elastic boundary wave present on the side of the first medium of the interface is denoted as E1? and the energy of an elastic boundary wave present on the side of the second medium of the interface is denoted as E2?, the energies of an elastic boundary wave would satisfy the relationship of E1/E2<E1?/E2? so that the sonic velocity of an elastic boundary wave in the IDT including the laminated conductor lay

Abstract: An electrical component has electrically conducting structures placed on an electrically isolating or semiconductive substrate and component structures sensitive to a voltage or an electrical arcing and galvanically separated from one another. To prevent an arcing between the galvanically separated component structures, the component structures are short-circuited with a shunt line having a smaller cross-section than the remaining electrical conductor tracks. The shunt lines can be burnt through by application of an electrical current at any given time, whereby a galvanic separation of the component structures is effected, if necessary, for the function of the component.

Abstract: In an acoustic wave filter device, a first filter circuit portion includes a first inductor provided in a series arm that couples an input terminal and an output terminal is serially connected to a first acoustic wave resonator, and a second filter circuit portion includes a second inductor provided in the series arm and second and third acoustic wave resonators and connected between one end and the other end of the second inductor and a ground potential. When the pass band center frequency is set as a first center frequency and the center frequency of a filter defined by the inductance of the first and second inductors and the capacitance of the first to third acoustic wave resonators is set as a second center frequency f2, f1 is less than f2.

Abstract: A piezoelectric thin-film resonator includes: a lower electrode provided on a substrate; a piezoelectric film provided on the lower electrode; an upper electrode provided on the piezoelectric film so as to face the lower electrode across the piezoelectric film to thus define a resonance portion; and a weight load film provided on the upper electrode, the weight load film being provided in the resonance portion and having an area smaller than that of the resonance portion.

Abstract: A surface acoustic wave device has a structure in which a surface acoustic wave element (11), provided with two kinds of surface acoustic wave filter structures having different center frequencies on the same piezoelectric substrate (12), is disposed on a package (16). The surface acoustic wave element (11) comprises a first filter structure (13) having a first center frequency, a second filter structure (14) having a second center frequency and a shield electrode (15) between the first filter structure (13) and the second filter structure (14). The shield electrode (15) is connected to an earth terminal (181) of the package (16) to be grounded. According to the structure, electromagnetic shielding between the first filter structure (13) and the second filter structure (14) can be performed, therefore, the isolation property therebetween can be improved and the surface acoustic wave device can be miniaturized.

Abstract: A surface acoustic wave (SAW) device includes at least an IC region and a SAW element region. A semiconductor element layer and wiring layer is located in the IC region, and the semiconductor element layer has a semiconductor element and an element insulating film. The wiring layer is formed by stacking wiring to connect with the semiconductor element and a wiring insulating film extending to the SAW region. The semiconductor element layer further includes a piezoelectric thin film formed above the wiring insulating film, and in the SAW element region, a SAW element is formed on the piezoelectric thin film equipped with an IDT electrode provided with a plurality of electrode fingers, and at least one layer of layer thickness adjusting films having linear shapes and arranged in parallel to and with the same pitch as the electrode fingers of the IDT electrode.

Abstract: A surface acoustic wave filter includes a surface acoustic wave substrate, an input transducer, and an output transducer. The input and output transducers are arranged on a surface of the surface acoustic wave substrate. Each of the input and output transducers includes a plurality of electrode fingers that is slanted in a direction that is substantially perpendicular to a surface acoustic wave propagation direction such that an electrode finger pitch changes in the direction that is substantially perpendicular to the surface acoustic wave propagation direction. An electrode finger pitch of a portion of the input transducer is different from an electrode finger pitch of a portion of the output transducer that corresponds to the portion of the input transducer in the surface acoustic wave propagation direction.

Abstract: A surface acoustic wave filter includes a device chip, one principal surface of a piezoelectric substrate having a wiring pattern including IDTs and pads electrically connected to the IDTs, that is disposed so as to oppose a mount board, with the pads being electrically connected to lands of the mount board through bumps. A resin film covers the other principal surface of the piezoelectric substrate and the principal surface of the mount board to seal the device chip. In the piezoelectric substrate, the area of the one principal surface is greater than the area of the other principal surface.

Abstract: An elastic boundary wave apparatus that is capable of suppressing an undesired response due to a comb-shaped capacitor electrode includes a first medium; a second medium stacked on the first medium; and a plurality of electrodes arranged in the boundary between the first and second media, wherein a filter and/or a resonator, and an electrostatic capacitor that is electrically connected to the filter and/or the resonator are defined by the plurality of electrodes, the filter and/or the resonator each include an IDT electrode, and the electrostatic capacitor is defined by a comb-shaped capacitor electrode.

Abstract: After electrode patterning on an electrode forming surface of a piezoelectric substrate 2 (FIG. 1(b)), a conductor layer is formed on an electrode non-forming surface of the piezoelectric substrate 2 (FIG. 1(c)). After forming the conductor layer, the conductor layer formed on the other surface is removed (FIG. 1(f)) after at least one step (FIG. 1(e)), and thereafter, dicing for separation into elements and mounting on a mounting substrate are carried out. By removing all the conductor layer on the other surface of the piezoelectric substrate, the out-of-passband attenuation and isolation performance can be significantly improved.

Abstract: A SAW filter includes multiple SAW resonators. The multiple SAW resonators, which are connected in series, are connected any one of between a signal input terminal and a ground that is the closest thereto and between a signal output terminal and another ground that is the closest thereto. The SAW resonators have substantially equal electrostatic capacitances. It is thus possible to protect the SAW resonators without providing a sacrificial electrode for electrostatic breakdown, and thereby possible to configure the SAW filter having a high reliability against the electrostatic discharge.

Abstract: An electromagnetic composite metamaterial including an electromagnetic medium and a plurality of spaced electromechanical resonators disposed in or on the electromagnetic medium configured to control electromagnetic wave propagation properties in the electromagnetic composite metamaterial.

Abstract: Surface acoustic wave (SAW) filter includes SAW resonators, a discharge induction pattern is provided between a ground and at least one of a signal input terminal and a signal output terminal, and the discharge induction pattern has multiple gaps that are narrower than gaps that exist inside electrode patterns of the SAW resonators. Since the discharge induction pattern has multiple gaps that are narrower than gaps that exist inside electrode patterns of the SAW resonators, it is possible to induce the electrostatic discharge without fault. The multiple gaps are provided so as to protect the SAW resonators against multiple times of electrostatic discharge.

Abstract: A resonator is connected in parallel to at least one serial-arm-connected resonator in a resonator type filter having a serial arm and a parallel arm. At this time, the resonance frequency of the resonator connected in parallel is set to be substantially the same as the resonance frequency of the parallel-arm-connected resonator. This makes it possible to prevent the deterioration of attenuation levels at the lower-frequency side of the filter, caused by an increase in the resistance of a connection element due to an increase in packaging density.

Abstract: In a surface acoustic wave device, an excitation electrode 5 in a surface acoustic wave element is provided on a lower surface of a piezoelectric substrate 3, and the lower surface of the piezoelectric substrate 3 is disposed in a state where it is opposed to an upper surface of a mounting base member 2. The surface acoustic wave device comprises a through hole 9 penetrating between the upper surface and a lower surface of the mounting base member 2, a lead electrode 10 closing the through hole 9 and formed so as to extend to the lower surface of the mounting base member 2, and an insulator 11 covering the lead electrode 10 so as to expose its partial area 16.

Abstract: Band reject filters are disclosed. A band reject filter includes a first acoustic resonator and a second acoustic resonator, each of which has either shunt resonators adapted to resonate substantially at respective resonance frequencies defining a rejection frequency band or series resonators adapted to anti-resonate substantially at respective anti-resonance frequencies defining the rejection frequency band. These resonators are connected through a phase shifter which imparts an impedance phase shift of approximately 45° to 135°. Exemplary applications of the band reject filters disclosed herein include implementation as an inter-stage band reject filter for a base station power amplifier for a wireless communication system, as a radio frequency band reject filter in a duplexer for a wireless communication terminal, and in a low noise amplifier input stage.

Abstract: A boundary acoustic wave filter device capable of increasing an out-of-band attenuation includes a dielectric film formed on a piezoelectric substrate, at least one longitudinally coupled resonator boundary acoustic wave filter having a plurality of IDTs disposed along a boundary between the piezoelectric substrate and the dielectric film, and at least two one-terminal-pair boundary acoustic wave resonators. At least one boundary acoustic wave resonator is connected in series to the longitudinally coupled resonator boundary acoustic wave filter, and at least remaining one boundary acoustic wave resonator is connected in parallel to the longitudinally coupled resonator boundary acoustic wave filter.

Abstract: A 5-IDT longitudinally coupled resonator-type SAW filter has a balanced-to-unbalanced conversion function. In areas where first to fifth IDTs are adjacent to each other, each IDT includes a narrow-pitched electrode finger portion. The IDTs are configured such that one condition selected from among conditions (1) to (3) and one condition selected from among conditions (4) to (6) are satisfied when the numbers and pitches of electrode fingers in the narrow-pitched portions of the first to fifth IDTs are denoted by N1 and P1, N2a and P2a, N2b and P2b, N3 and P3, N4a and P4a, N4b and P4b, and N5 and P5, respectively: Conditions (1): When N1=N3=N5, 0.992?P1/P3?1.008 and P1=P5 (2): When N1=N5<N3, 0.9?P1/P3<1 and P1=P5 (3): When N3<N1=N5, 1 <P1/P3?1.1 and P1=P5 (4): When N2a=N2b=N4a=N4b, 0.991?P2a/P2b?1.009 and P2a/P2b=P4b/P4a (5): When N2a=N4b>N2b=N4a, 1<P2a/P2b?1.1 and P2a/P2b=P4b/P4a (6): When N2a=N4b<N2b=N4a, 0.

Abstract: A piezoelectric filter that includes a first substrate having at least one first piezoelectric resonator disposed on a main surface thereof; a second substrate having at least one second piezoelectric resonator disposed on a main surface thereof. A connection pattern extends around the first piezoelectric resonator and the second piezoelectric resonator and is disposed between the first substrate and the second substrate such that the main surface of the first substrate faces the main surface of the second substrate, and the first piezoelectric resonator is remote from the second piezoelectric resonator. A connecting layer bonds a pad disposed on the main surface of the first substrate to a pad disposed on the main surface of the second substrate, and is electrically connected to the first piezoelectric resonator and the second piezoelectric resonator.

Abstract: A piezoelectric filter which has a small circuit scale and device size and can reduce a loss, is provided. The piezoelectric filter (1) has an input impedance smaller than an output impedance. The piezoelectric filter (1) comprises an input terminal (101a), an output terminal (101b), series piezoelectric resonators (102a, 102b, 102c), and parallel piezoelectric resonators (103a, 103b, 103c). Among the parallel piezoelectric resonators (103a, 103b, 103c), on an equivalent circuit, a capacitance of a first parallel piezoelectric resonator (103a) close to the input terminal (101a) side is larger than a capacitance of a second parallel piezoelectric resonator (103c) close to the output terminal (101b) side.

Abstract: A lattice-type filter circuit includes first and second balanced signal terminals; first and second balanced signal terminals; a first resonator connected to a series arm between the first balanced signal terminal on the input side and the first balanced signal terminal on the output side; a second resonator connected to a series arm between the second balanced signal terminal on the input side and the second balanced signal terminal on the output side; a first resonant circuit including impedance elements, being connected to a lattice arm between the first balanced signal terminal on the output side and the second balanced signal terminal on the input side; and a second resonant circuit including impedance elements, being connected to a lattice arm between the second balanced signal terminal on the output side and the first balanced signal terminal on the input side.

Abstract: An acoustic wave device includes an acoustic wave element formed on a piezoelectric substrate, and a terminal that makes an electric connection with an outside of the acoustic wave device. The terminal has a protrusion electrode having a side surface coated with a coating film having a non-coating portion.

Abstract: A filter device has a novel structure, satisfying requirements to have balanced input and output, with a small number of configuration elements. The above filter device includes first and second balanced signal terminals on the input side to be connected to an external balance circuit; first and second balanced signal, terminals on the output side to be connected to an external balance circuit; at least one first resonator connected in series between the first balanced signal terminal on the input side and the first balanced signal terminal on the output side; at least one second resonator connected in series between the second balanced signal terminal on the input side and the second balanced signal terminal on the output side; and at least one impedance element connected between the first balanced signal terminal on the output side and the second balanced signal terminal on the input side.

Abstract: The number of times for averaging operation for averaging a correlation value of a received signal and a reference signal is properly controlled. When the correlation value is not averaged, since a lower limit value TH_A of a correlation level of a distribution of timings of which a path exists is larger than an upper limit value TH_B of a correlation level of a distribution of timings of which a path does not exist, the correlation value of a path is hidden by noise. Since the averaging operation is repeated until the relation of TH_A>TH_B is satisfied, the averaging operation is stopped when the relation is satisfied. The TH_A and TH_B are decided in accordance with RSCP and ISCP of a pilot channel and RSSI of a received base band signal.

Abstract: A surface acoustic wave (SAW) device includes a piezoelectric substrate, a first and a second interdigital transducers (IDT) provided thereon. The second IDT has a side that is substantially aligned with a corresponding side of the first IDT, and another side of the second IDT is arranged so that the second IDT may adjust a leaked wave caused resulting from by a power-flow angle of the piezoelectric substrate.

Abstract: The present invention provides an antenna duplexer comprising a transmitting filter and a receiving filter which are mounted on a package, a transmitting signal input pad and a transmitting signal output pad which are connected to input and output ends of the transmitting filter, a receiving signal input pad and a receiving signal output pad which are connected to input and output ends of the receiving filter, and at least one grounding pad. The pads are arranged, on a surface of the package, along at least two sides of four sides of a quadrangle. The transmitting signal input pad and the receiving signal output pad are disposed at diagonal positions of the quadrangle and are furthest away from one another.

Abstract: A surface acoustic wave device is provides and comprises a flexible substrate having a first side and a piezoelectric film attached to at least a portion of the first side of the flexible substrate. The piezoelectric film can have a first side and a second side. A surface acoustic wave circuit can adjoin at least a portion of the first side of the piezoelectric film. These devices can comprise thin and flexible substrates, such as polyimide to make the devices flexible. If adhesive is applied to the back of devices constructed in accordance with the invention, such devices can be adhered to almost any surface, even a curved surface. The devices of the present invention can be easily integrated with other devices.

Abstract: In a balanced SAW filter, a second IDT and a fourth IDT of a five IDT type first longitudinally-coupled-resonator SAW filter element are connected via first and second wiring lines to a seventh IDT and a ninth IDT of a five IDT type second longitudinally-coupled-resonator SAW filter element, respectively. First, third, and fifth IDTs are connected to an unbalanced terminal. A sixth IDT and a first sub-IDT portion are connected to a first balanced terminal. A second sub-IDT portion and a tenth IDT are connected to a second balanced terminal. The IDTs are arranged such that the phase of an electrical signal transmitted through the first wiring line differs by 180 degrees from the phase of an electrical signal transmitted through the second wiring line.

Abstract: A surface acoustic wave filter includes first to fifth IDTs arranged on a piezoelectric substrate along a surface acoustic wave propagation direction. The second IDT and the fourth IDT have a phase difference of 180° with respect to each other. The second and fourth IDTs are connected to an unbalanced terminal. The third IDT includes a first sub-IDT portion and a second sub-IDT portion. The first IDT and the first sub-IDT portion are connected to a first balanced terminal, and the second sub-IDT portion and the fifth IDT are connected to a second balanced terminal. The following conditions: 1.55?N3/N1?2.58 and N1=N5 are satisfied, where N1 denotes the number of electrode fingers that determines the center frequency of the first IDT, N3 denotes the number of electrode fingers that determines the center frequency of the third IDT, and N5 denotes the number of electrode fingers that determines the center frequency of the fifth IDT.

Abstract: A method of manufacturing a piezoelectric beam is provided. The method includes inserting a piezoelectric body and a pair of roller pins into an injection molding form. Once the piezoelectric body and roller pins are enclosed within the injection mold form a liquefied substance is injected into the injection molding form. The liquefied substance solidifies to substantially permanently affix the roller pins to opposing distal ends of the body.

Abstract: In a balanced SAW filter, a third IDT of a first SAW filter element includes first and second IDT segments, and similarly, an eighth IDT of a second SAW filter element includes first and second IDT segments. A first IDT, the first IDT segment, the second IDT segment, and a fifth IDT included in the first SAW filter element are respectively connected to a sixth IDT, the first IDT segment, the second IDT segment, and a tenth IDT segment included in the second SAW filter element by first to fourth wiring lines. The phase of electric signals transmitted through the first and third wiring lines differs from the phase of electric signals transmitted through the second and fourth wiring lines by 180°.

Abstract: A method of Partial Parallel Interference Cancellation (PPIC) is provided for recursively eliminating the Multiple Access Interference from a received signal. Such method is to use a recursion way to eliminate all the Multiple Access Interference (MAI) one by one from the received signal. Moreover, the present invention is to take the output of the pre-stage as the input of the present stage with the recursion method so that we can use only one operating circuit to obtain the function the MAI eliminating.

Abstract: A cancellation circuit to remove the anti-resonance signal from a resonator. Micro-mechanical and surface and bulk acoustic wave resonators include an anti-resonance in an output signal. This has an undesirable effect on certain types of systems in their function and performance. An anti-resonance cancellation circuit removes the anti-resonance from the output of the resonators by providing a signal which is subtracted from the output of the resonator. The cancellation circuit includes a capacitor which is matched to the static capacitance of the resonator. The loads of the resonator and cancellation network are also matched.

Abstract: According to some embodiments, a pre-poled, single-domain body of a ferroelectric crystalline material such as lithium tantalate or lithium niobate is electrically reduced by applying a voltage across the body in a non-oxidizing environment while the body is heated to a process temperature below its Curie temperature. The voltage generates an electric field along the polar axis of the body. Electrodes may be formed on the body surface by applying an acetate-based silver paint.

Abstract: An integrated SAW device features an electronic assembly, a SAW device mounted to the electronic assembly, and a heater element on the SAW device to minimize thermal resistance between the SAW device and the heater element.

Abstract: An IDT electrode 2 and an electrode pad 3 are formed on one principal face of a piezoelectric substrate 1 and a circular electrode 4 is formed so as to surround these components. The circular electrode 4 is connected to a radiating conductor 15 formed on a bottom face of a circuit board 11 through a via conductor 14 formed within the circuit board 11. Thus, since heat generated in the IDT electrode 2 is easy to be released to the outside through the circular electrode 4, the via conductor 14 and the radiating conductor 15, adverse effects due to the heat can be prevented, thereby improving high power durability.

Abstract: A surface acoustic wave branching filter reduces deterioration of the insertion loss and improves the isolation characteristics. The surface acoustic wave filter includes first ends of a first acoustic wave filter, having a relatively low passband, and a second acoustic wave filter, having a relatively high passband, connected to a first common terminal which is connected to an antenna. A resonator of the first surface acoustic wave filter, among a plurality of parallel-arm resonators and a plurality of series-arm resonators, which is closest to the first common terminal is a parallel-arm resonator. The capacitance of the parallel-arm resonator that is closest to the first common terminal is less than ½ of the capacitance of the other parallel-arm resonators.

Abstract: A branching filter includes a first filter with a relatively low passband and having a first temperature property-improvement thin film, and a second filter with a relatively high passband and having a second temperature property-improvement thin film. In the branching filter, the thickness of the first temperature property-improvement thin film is different from that of the second temperature property-improvement thin film such that the temperature coefficient of frequency of the first filter is greater than that of the second filter.