JP2008028825A - Surface acoustic wave device and communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface acoustic wave device that reduces the occurrence of ripples in a passband, can improve balancing in the passband, and has excellent characteristics, and to provide a communication device using the surface acoustic wave device. <P>SOLUTION: First and second surface acoustic wave elements 31, 32 are connected to an unbalanced signal terminal 12 and are connected to balanced signal terminals 13, 14, respectively. Cross wiring sections 23-26 are formed, where lead wires 27, 28 for grounding connected to a bus bar electrode at the sides of the balanced signal terminals 13, 14 of the IDT electrode of the first and second surface acoustic wave devices 31, 32 cross lead wires 19-22 for all signals, where the first and second surface acoustic wave devices 31, 32 are connected to the balanced signal terminals 13, 14 via insulators 15-18. The cross wiring sections 23-26 are formed symmetrically with the IDT electrodes 3, 6 arranged at the center of odd number of IDT electrodes 2-4 and 5-7. Resistance generated by respective cross wiring sections 23-26 is nearly the same. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface acoustic wave device such as a surface acoustic wave filter or a surface acoustic wave resonator used in a mobile communication device such as a mobile phone, and a communication device including the same.

  Conventionally, a surface acoustic wave filter has been widely used as a frequency selection filter used in an RF (radio frequency) stage of a mobile communication device such as a mobile phone or a car phone. In general, characteristics required for a frequency selective filter include various characteristics such as a wide passband, low loss, and high attenuation. In recent years, there has been an increasing demand for lower loss for surface acoustic wave filters in order to improve reception sensitivity and lower power consumption particularly in mobile communication devices. In recent years, in mobile communication devices, the antenna has been shifted from a conventional whip antenna to a built-in antenna using dielectric ceramics for miniaturization. For this reason, it is difficult to obtain a sufficient antenna gain, and there is an increasing demand for further improving the insertion loss of the surface acoustic wave filter.

  In order to realize such a broad band and low loss, for example, three IDT electrodes (Inter Digital Transducer) are provided on a piezoelectric substrate, and a dual mode elastic surface using a longitudinal primary mode and a longitudinal tertiary mode is used. Wave resonator filters have been proposed.

  In particular, by providing a narrow pitch portion of electrode fingers at the ends of adjacent IDT electrodes, the radiation loss of bulk waves between the IDT electrodes is reduced, and the state of the resonance mode is controlled to achieve a wider band and lower loss. (For example, refer to Patent Document 1).

  In recent years, surface acoustic wave devices have been required to be miniaturized in order to reduce the size and weight of mobile communication devices, and the mounting form has been changed from a conventional package mounting using a wire bonding method to a flip chip mounting method. It has changed to the CSP (Chip Scale Package) type used. Therefore, not only the mounting form but also the surface acoustic wave device itself tends to be further miniaturized.

  FIG. 7 is a plan view schematically showing an electrode structure of a conventional surface acoustic wave filter. The front surface acoustic wave filters 212 and 213 connected in parallel on the piezoelectric substrate 201 are formed, and the surface acoustic wave filters 212 and 213 are formed by three IDT electrodes 202, 203, and 204, and 205, 206, and 207, respectively. And reflector electrodes 208, 209 and 210, 211 arranged on both sides thereof. In addition, surface acoustic wave filters 216 and 217 are formed in the latter stage, and the surface acoustic wave filters 216 and 217 are arranged on three sides of three IDT electrodes 218, 219, 220 and 221, 222, 223, respectively. And reflector electrodes 224, 225 and 226, 227. Surface acoustic wave resonators 214 and 215 are provided between the surface acoustic wave filters 212 and 213 at the front stage and the surface acoustic wave filters 216 and 217 at the rear stage, respectively.

  The surface acoustic wave filters 212 and 213 connected to the unbalanced signal terminal 231 are further connected to the surface acoustic wave filters 216 and 217 via the surface acoustic wave resonators 214 and 215. The IDT electrodes 203 and 206 connected to the unbalanced signal terminal 231 apply an electric field to a pair of mutually opposed comb-like electrodes to excite surface acoustic waves. The excited surface acoustic wave propagates to the IDT electrodes 202, 204 and 205, 207. Further, the phase of the central IDT electrode 203 is opposite in phase by 180 ° with respect to the phase of the other central IDT electrode 206, and finally the center of the subsequent surface acoustic wave filters 216 and 217. A signal is transmitted from one comb-like electrode of the IDT electrodes 219 and 222 to the balanced output signal terminals 232 and 233, and is balanced and output. With such a structure, a balanced-unbalanced conversion function is realized. Further, the surface acoustic wave element itself can be miniaturized by adopting a three-dimensional wiring structure through insulators 241 to 248 for a part of the wiring between the surface acoustic wave element and the surface acoustic wave resonator. (For example, see Patent Document 2).

  In recent years, in order to reduce the size, weight, and cost of mobile communication devices, the number of components used has been reduced, and a new function has been required for the surface acoustic wave filter. One of the requirements is that it can be configured as an unbalanced input-balanced output type or a balanced input-unbalanced output type. Here, the balanced input or the balanced output means that a signal is input or output as a potential difference between two signal lines, and the signals of the signal lines have the same amplitude and the phases are reversed. On the other hand, unbalanced input or unbalanced output means that a signal is input or output as the potential of one line with respect to the ground potential.

At present, an unbalanced input-balanced output type surface acoustic wave filter or a balanced input-unbalanced output type surface acoustic wave filter (hereinafter referred to as an unbalanced-balanced conversion function or balanced-unbalanced conversion function) The balanced surface acoustic wave filter is being put to practical use. In order to satisfy the requirement of the unbalance-balance conversion function, a longitudinally coupled double mode filter is often used. In addition, as an RF filter, there is a great demand to match one input terminal of an unbalanced connection with an input / output impedance of 50Ω and the other balanced connection with an input / output impedance of 100 to 200Ω.
Japanese Patent Laid-Open No. 2002-9587 JP 2004-282707 A

  When a conventional surface acoustic wave device (surface acoustic wave filter) disclosed in Patent Document 2 as shown in FIG. 7 is used, between surface acoustic wave elements or between a surface acoustic wave element and a surface acoustic wave resonator. By adopting a three-dimensional wiring as a part of the wiring, the surface acoustic wave filter can be downsized. However, when a three-dimensional wiring structure is used only on one side of the balanced signal wiring or the unbalanced signal wiring, the insertion loss is degraded due to the occurrence of ripples in the passband in the frequency characteristics of the passband of the surface acoustic wave filter. There was a problem to do.

  Further, in the surface acoustic wave device disclosed in Patent Document 1, when a narrow pitch portion is provided at the end of the IDT electrode, there are portions where the electrode finger pitch is different in a state where the surface acoustic waves are coupled, so that the passband The ripple of the filter characteristic at the point becomes large, the shoulder characteristic of the pass band deteriorates, and the flat characteristic of the pass band cannot be obtained. Also, simply providing a narrow pitch portion at the end of the IDT electrode limits the number of basic resonance modes that can be used for excitation of surface acoustic waves to the longitudinal first-order mode and the longitudinal third-order mode. Since it cannot be used, the degree of freedom in design was small. Therefore, it has been insufficient to improve the insertion loss while improving the flatness of the filter characteristics in the passband and increasing the bandwidth.

  Furthermore, in the surface acoustic wave device disclosed in Patent Document 2, since the three-dimensional wiring is used only for a part of the wiring between the surface acoustic wave elements, the wiring resistance and the wiring capacitance are asymmetric in the lead wiring. There was a problem that the amplitude balance and the phase balance deteriorated.

  Accordingly, the present invention has been completed in view of the above-mentioned problems in the prior art, and its purpose is to realize downsizing and to suppress the occurrence of ripple without deteriorating the insertion loss in the passband. An object of the present invention is to provide a surface acoustic wave device that can function as a high-quality balanced surface acoustic wave filter, and a communication device using the same.

  The surface acoustic wave device according to the present invention includes: 1) three pieces having a plurality of electrode fingers that are long on the piezoelectric substrate in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. 1st and 2nd elasticity which has the above-mentioned odd number of IDT electrodes, and a reflector electrode which is arranged on both sides of the above-mentioned odd number of IDT electrodes and has a plurality of long electrode fingers in the direction orthogonal to the propagation direction A surface acoustic wave element is formed, and the first and second surface acoustic wave elements are surface acoustic wave devices connected to an unbalanced signal terminal and each connected to a balanced signal terminal, A ground lead wire connected to the bus bar electrode on the balanced signal terminal side of the IDT electrode of the first and second surface acoustic wave elements, the first and second surface acoustic wave elements, and the balanced signal terminal; For all signals connected The lead-out wiring forms cross wiring portions that are arranged so as to cross each other through an insulator, and the cross wiring portion includes an IDT electrode arranged in the center of the odd number of IDT electrodes. It is formed symmetrically at the center, and the resistance generated by each of the cross wiring portions is substantially the same.

  In addition, the surface acoustic wave device of the present invention includes 2) a plurality of electrode fingers that are long on the piezoelectric substrate in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. First and second having three or more odd-numbered IDT electrodes and reflector electrodes each provided on both sides of the odd-numbered IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction The first and second surface acoustic wave elements are connected to an unbalanced signal terminal, and are respectively connected to the subsequent stages of the first and second surface acoustic wave elements. A surface acoustic wave device to which a surface acoustic wave resonator connected to a balanced signal terminal is connected, the bus bar on the surface acoustic wave resonator side of the IDT electrode of the first and second surface acoustic wave elements. Grounding lead wire connected to the electrode and All signal lead-out wirings connecting the first and second surface acoustic wave elements and the surface acoustic wave resonators respectively form cross wiring portions arranged so as to cross each other through an insulator. The cross wiring portions are symmetrically formed around the IDT electrode disposed in the center of the odd number of IDT electrodes, and the resistances generated by the cross wiring portions are substantially the same. It is characterized by this.

  In the surface acoustic wave device according to the present invention, 3) in the configuration of 2), the third and fourth surface acoustic wave elements are further connected to the subsequent stage of the surface acoustic wave resonator. And a ground lead wire connected to the bus bar electrode on the surface acoustic wave resonator side of the IDT electrode of the fourth surface acoustic wave element, the surface acoustic wave resonator, and the third and fourth surface acoustic waves. All the signal lead wires connected to the elements form cross wiring portions arranged so as to cross each other through an insulator, and the cross wiring portions are formed at the center of the odd number of IDT electrodes. Are formed symmetrically with respect to the IDT electrode arranged at the center, and the resistance generated by each of the cross wiring portions is substantially the same.

  In addition, the surface acoustic wave device of the present invention is provided with 4) a plurality of electrode fingers on the piezoelectric substrate that are long in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. First and second having three or more odd-numbered IDT electrodes and reflector electrodes each provided on both sides of the odd-numbered IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction The first and second surface acoustic wave elements are connected to an unbalanced signal terminal, and are respectively connected to the subsequent stages of the first and second surface acoustic wave elements. A surface acoustic wave device to which third and fourth surface acoustic wave elements connected to balanced signal terminals are connected, wherein the IDT electrodes of the first and second surface acoustic wave elements are the first ones. Bus bar electricity on the 3rd and 4th surface acoustic wave element side And a ground lead wire connected to the bus bar electrodes on the first and second surface acoustic wave resonator sides of the IDT electrodes of the third and fourth surface acoustic wave elements. And all signal lead-out wirings connecting the first and second surface acoustic wave elements and the third and fourth surface acoustic wave elements are arranged so as to cross each other through an insulator. Cross wiring portions are respectively formed, and the cross wiring portions are formed symmetrically around an IDT electrode disposed in the center of the odd number of IDT electrodes, and each cross wiring portion The generated resistance is substantially the same.

  In the surface acoustic wave device according to the present invention, 5) in any one of the above-described 1) to 4), the first and second surface acoustic wave elements are connected to each other through the surface acoustic wave resonator. It is connected to a signal terminal.

  The surface acoustic wave device according to the present invention includes 6) a plurality of electrode fingers that are long on the piezoelectric substrate in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. A surface acoustic wave device having an odd number of IDT electrodes of 5 or more and reflector electrodes each provided on both sides of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction. The surface acoustic wave device is a surface acoustic wave device connected to an unbalanced input terminal and an unbalanced output terminal, and is provided on the unbalanced input terminal side of the IDT electrode of the surface acoustic wave device. A grounding lead wire and all signal lead wires connecting the surface acoustic wave element and the unbalanced input terminal form crossing wiring portions arranged so as to cross each other through an insulator, respectively. And said The grounding lead wire on the unbalanced output terminal side of the IDT electrode of the surface acoustic wave element and all the signal lead wires connecting the surface acoustic wave element and the unbalanced output terminal are interposed via an insulator. And the cross wiring portions are symmetrically formed around the IDT electrodes disposed in the center of the odd number of IDT electrodes. The resistance generated by each of the cross wiring portions is substantially the same.

  The communication device of the present invention is characterized in that it includes 7) at least one of a receiving circuit and a transmitting circuit having a surface acoustic wave device having any one of the above-described configurations 1) to 6).

  According to the surface acoustic wave device of the present invention, the piezoelectric substrate includes three or more electrode fingers each having a plurality of long electrode fingers in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. First and second surface acoustic wave elements each having an odd number of IDT electrodes and reflector electrodes each provided on both sides of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction are provided. The first and second surface acoustic wave elements formed are connected to an unbalanced signal terminal (unbalanced input (output) force terminal) and each is connected to a balanced signal terminal (balanced output (input) force terminal). ) Connected to the bus bar electrode on the balanced signal terminal side of the IDT electrode of the first and second surface acoustic wave elements, and the first and second All connected surface acoustic wave elements and balanced signal terminals The signal lead-out wirings form cross wiring portions that are arranged so as to intersect with each other via an insulator, and the cross wiring portions are centered on the IDT electrodes that are arranged in the center of the odd number of IDT electrodes. In addition, since the resistance generated by each cross wiring portion is substantially the same, the resistance and the capacitance generated in each cross wiring portion can be made substantially the same. Are substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band.

  In addition, the resistance generated in the cross wiring portion is caused by a small change in thickness or shape such that, for example, the wiring on the upper side of the cross wiring portion is partially thin, bent up or down, or has a step. Therefore, the resistance is likely to be slightly higher than other wiring portions. With respect to the cross wiring portion showing a different resistance value from the other wiring portions, it is possible to obtain the above-described effects (effects such as improved insertion loss) by making the resistance of each cross wiring portion substantially the same. it can. In addition, in order to make the resistance of each cross wiring portion substantially the same, for example, the formation method thereof, that is, the formation conditions of the wiring portion by sputtering method, the formation of insulators such as CVD method, photolithography method and build-up method This can be achieved by making the conditions the same.

  Further, according to the surface acoustic wave device of the present invention, three piezoelectric fingers having a plurality of long electrode fingers in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate are provided on the piezoelectric substrate. First and second surface acoustic waves each having the above-mentioned odd number of IDT electrodes and reflector electrodes each provided on both sides of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in the direction orthogonal to the propagation direction An element is formed, and the first and second surface acoustic wave elements are connected to the unbalanced signal terminal and connected to the balanced signal terminal at each subsequent stage of the first and second surface acoustic wave elements. A surface acoustic wave device to which the surface acoustic wave resonator is connected, wherein the grounding lead wire is connected to the bus bar electrode on the surface acoustic wave resonator side of the IDT electrode of the first and second surface acoustic wave elements And the first and second surface acoustic wave elements and the bullet All the signal lead wires connected to the surface wave resonators form cross wiring portions that are arranged so as to cross each other through an insulator, and the cross wiring portions are formed in an odd number of IDT electrodes. Since the IDT electrode disposed in the center is symmetrically formed and the resistance generated by each cross wiring portion is substantially the same, the resistance in each cross wiring portion, as described above, Can have substantially the same capacitance, and as a result, the current flowing through the wiring is substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Further, since the cross wiring portion is formed symmetrically around the IDT electrode disposed in the center in the odd number of IDT electrodes, the resistance and the capacitance introduced on the equivalent circuit of the surface acoustic wave device can be reduced. In the first surface acoustic wave element and the second surface acoustic wave element, it is possible to finely adjust with high accuracy, and the amplitude balance and the phase balance can be improved.

  Furthermore, with the above configuration, there is no need to dispose a grounding pad electrode or the like between the unbalanced input terminal or unbalanced output terminal and the surface acoustic wave element (longitudinal resonator type surface acoustic wave filter). Patterns such as ground pad electrodes can be laid out in areas outside the surface acoustic wave elements or between the surface acoustic wave elements and the surface acoustic wave resonators, and the surface area can be reduced by reducing the device area as much as possible. The apparatus can be miniaturized.

  In the surface acoustic wave device of the present invention, preferably, third and fourth surface acoustic wave elements are further connected to the subsequent stage of the surface acoustic wave resonator, and the third and fourth surface acoustic wave elements are connected. A grounding lead wire connected to the bus bar electrode on the surface acoustic wave resonator side of the IDT electrode, and all signal lead wires connecting the surface acoustic wave resonator and the third and fourth surface acoustic wave elements. The cross wiring portions are formed so as to cross each other through the insulator, and the cross wiring portions are formed symmetrically around the IDT electrodes arranged at the center of the odd number of IDT electrodes. In addition, since the resistance generated by each cross wiring portion is substantially the same, the resistance and the capacitance in the cross wiring portion can be made substantially the same as described above, and the current flowing through the wiring is substantially equal. Will be the same and pass The region of the ripple can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Furthermore, the amount of attenuation outside the passband can be greatly reduced.

  Further, the surface acoustic wave device of the present invention includes three or more electrode fingers each having a plurality of long electrode fingers in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. First and second surface acoustic wave elements each having an odd number of IDT electrodes and reflector electrodes each provided on both sides of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction are provided. The first and second surface acoustic wave elements are connected to the unbalanced signal terminal, and are connected to the balanced signal terminal at each subsequent stage of the first and second surface acoustic wave elements, respectively. A surface acoustic wave device to which the third and fourth surface acoustic wave elements are connected, wherein the IDT electrodes of the first and second surface acoustic wave elements are on the third and fourth surface acoustic wave resonator sides. Grounding lead wires connected to the bus bar electrodes of Grounding lead wires connected to the first and second surface acoustic wave resonator-side bus bar electrodes of the IDT electrodes of the third and fourth surface acoustic wave elements; the first and second surface acoustic wave elements; All of the signal lead-out wirings connected to the third and fourth surface acoustic wave elements respectively form cross wiring portions arranged so as to cross each other through an insulator, and the cross wiring portions are odd numbers. In the IDT electrodes, the IDT electrodes arranged in the center are symmetrically formed, and the resistance generated by each cross wiring portion is substantially the same. The resistance and further the capacitance can be made substantially the same, the current flowing through the wiring is substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Furthermore, since the two-stage longitudinally coupled surface acoustic wave filters are connected in cascade, the amount of attenuation outside the passband can be greatly reduced.

  In the surface acoustic wave device according to the present invention, preferably, the first and second surface acoustic wave elements are connected to the unbalanced signal terminal via the surface acoustic wave resonator, whereby the first and second surface acoustic wave devices are provided. If the electric capacity of the IDT electrode is the same as that of the conventional surface acoustic wave device using one surface acoustic wave element instead of the surface acoustic wave element, the crossing width of the IDT electrode of the surface acoustic wave element Can be reduced to half that of a conventional surface acoustic wave resonator, and the resistance loss can be reduced as compared with the conventional surface acoustic wave element, so that the insertion loss of the surface acoustic wave device can be improved. . Further, the surface acoustic wave resonators are arranged side by side in a direction orthogonal to the propagation direction, and are connected in parallel to the bus bar electrodes of the IDT electrodes of the first and second surface acoustic wave resonator portions. Therefore, the resistance loss can be reduced as compared with the conventional surface acoustic wave device, so that the insertion loss of the surface acoustic wave device can be improved.

Further, since the first and second surface acoustic wave elements are connected in parallel to the unbalanced signal terminal via the surface acoustic wave resonator, the resistance loss can be reduced as compared with the conventional surface acoustic wave device. So
Further, the surface acoustic wave device according to the present invention includes five or more electrode fingers each having a plurality of long electrode fingers in a direction perpendicular to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. A surface acoustic wave element having an odd number of IDT electrodes and reflector electrodes each provided on both sides of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction is formed. The surface acoustic wave device is a surface acoustic wave device connected to an unbalanced input terminal and an unbalanced output terminal, and includes a ground lead wire on the unbalanced input terminal side of the IDT electrode of the surface acoustic wave device, and a surface acoustic wave device. And all signal lead-out wirings connected to the unbalanced input terminals form cross wiring portions arranged so as to cross each other through an insulator, and the IDT electrodes of the surface acoustic wave element are not connected. Connection on the balanced output terminal side The lead wire for wiring and all the signal lead wires connected to the surface acoustic wave element and the unbalanced output terminal respectively form a cross wiring portion arranged so as to cross each other through an insulator. The wiring portion is formed symmetrically around the IDT electrode arranged in the center in the odd number of IDT electrodes, and the resistance generated by each cross wiring portion is substantially the same, so that the same as above The resistance and the capacitance in the cross wiring portion can be made substantially the same, the current flowing through the wiring becomes substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Further, since the surface acoustic wave element is configured by five or more IDT electrodes, the bandwidth in the pass band can be widened. In addition, this configuration eliminates the need for ground pad electrodes between the surface acoustic wave elements and the like. Further, the ground electrodes can be combined into one, and the surface area of the surface acoustic wave device can be reduced by reducing the device area as much as possible. Can be realized.

  The communication device according to the present invention includes the above-described surface acoustic wave device according to the present invention, and includes at least one of the reception circuit and the transmission circuit, thereby satisfying severe insertion loss and balance required conventionally. Thus, it is possible to realize a communication apparatus with reduced power consumption and extremely good sensitivity.

  Embodiments of a surface acoustic wave device according to the present invention will be described below in detail with reference to the drawings. The surface acoustic wave device of the present invention will be described taking a resonator type surface acoustic wave filter as an example. In addition, in drawing demonstrated below, the same code | symbol shall be attached | subjected to the same structure. In addition, the number of electrodes and the distance between the electrodes, such as the size of each electrode and the distance between the electrodes, are schematically illustrated for the purpose of explanation.

  FIG. 1 shows a plan view of an example of an embodiment of an electrode structure of a surface acoustic wave device according to the present invention. As shown in FIG. 1, the surface acoustic wave device according to the present invention has a long electrode finger in a direction perpendicular to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate 1 on the piezoelectric substrate 1. A plurality of odd-numbered IDT electrodes 2 to 4 and 5 to 7 and a plurality of odd-numbered IDT electrodes 2 to 4 and 5 to 7 are arranged on both sides, and are long electrode fingers in a direction perpendicular to the propagation direction. Are formed, and first and second surface acoustic wave elements 31 and 32 having a plurality of reflector electrodes 8 to 11 are formed, and the first and second surface acoustic wave elements 31 and 32 are unbalanced signals. A surface acoustic wave device that is connected to a terminal (unbalanced input (out) force terminal) 12 and is connected to balanced signal terminals 13 and 14, respectively, and includes first and second surface acoustic wave elements 31, 32 IDT electrodes 2 to 7 balanced signal terminal (balanced output terminal) 1 , 14 grounding lead wires 27 and 28 connected to the bus bar electrodes, and all signal lead wires 19 connecting the first and second surface acoustic wave elements 31 and 32 and the balanced signal terminals 13 and 14. ˜22 form cross wiring portions 23 to 26 arranged crossing each other through insulators 15 to 18, and the cross wiring portions 23 to 26 include odd number of IDT electrodes 2 to 4 and 5-7, the IDT electrodes 3 and 6 arranged in the center are symmetrically formed, and the resistances generated by the respective cross wiring portions 23 to 26 are substantially the same.

  As a result, the resistance and capacitance of the cross wiring portions 23 to 26 can be made substantially the same, the currents flowing through the wiring are substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band.

  In the present invention, the resistance generated by the cross wiring portions 23 to 26 is about 1.5Ω or less, and if it exceeds 1.5Ω, the loss of the signal increases due to the increase in resistance. In addition, although the resistances generated by the cross wiring portions 23 to 26 are substantially the same, the difference between the resistance of the cross wiring portion 23 and the resistance of the cross wiring portion 24 and the resistance of the cross wiring portion 25 and the resistance of the cross wiring portion 26 are the same. The difference may be 10% or less. If it exceeds 10%, the difference in amplitude between the two balanced output (input) force signals becomes large, and the degree of amplitude balance tends to deteriorate.

  Further, electrical capacitance is also generated in the cross wiring portions 23 to 26, the value thereof is about 0.1 pF or less, and the respective capacitances generated by the cross wiring portions 23 to 26 are substantially the same. The difference between the capacitance of the cross wiring portion 23 and the capacitance of the cross wiring portion 24 and the difference between the capacitance of the cross wiring portion 25 and the capacitance of the cross wiring portion 26 may be 10% or less. If it exceeds 10%, the difference between the two balanced output (input) force signals from a predetermined phase difference (phase difference 180 °) becomes large, and the phase balance tends to deteriorate.

  The cross wiring portions 23, 24, 25, and 26 are formed symmetrically around the IDT electrodes 3 and 6 disposed in the center in the odd number of IDT electrodes 2 to 4 and 5 to 7. For example, the IDT electrodes 3 and 6 are formed in line symmetry with respect to a central axis parallel to the direction orthogonal to the propagation direction of the surface acoustic wave, in other words, a central axis parallel to the longitudinal direction of the electrode fingers.

  As the insulators 15 to 18 of the present invention, silicon oxide, polyimide resin, acrylic resist, or the like is preferably used. Thereby, the insulation between the ground lead-out wiring 27 and the signal lead-out wirings 19 and 20 and the insulation between the ground lead-out wiring 28 and the signal lead-out wirings 21 and 22 can be kept good. it can.

  The thickness of the insulators 15 to 18 is preferably about 1.0 μm to 10.0 μm. If the thickness is less than 1.0 μm, it is difficult to ensure the insulation between the wirings. Is difficult to suppress, and the reliability of the surface acoustic wave device is likely to decrease.

  The insulators 15 to 18 are formed by a method such as a build-up method. When forming the insulators 15-18, it is good also as a structure which laminated | stacked the some insulating layer.

  Further, by mixing insulator particles made of alumina ceramic or the like or metal particles made of silver or the like into the insulators 15 to 18, or making the insulators 15 to 18 a porous body in which a large number of bubbles are formed. Thus, the dielectric constant of the insulators 15 to 18 can be adjusted to a desired one.

The cross wiring parts 23 to 26 are formed as follows, for example. First, on the main surface of the piezoelectric substrate 1, a metal layer that becomes each electrode of the IDT electrodes 2 to 7 and the reflector electrodes 8 to 11 is formed. A sputtering apparatus is used for forming the metal layer, and an Al (99 mass%)-Cu (1 mass%) alloy or the like is used as a material for the metal layer. Next, a photoresist is spin-coated on the metal layer to a thickness of about 0.5 μm, patterned into a desired shape by a reduction projection exposure apparatus (stepper), and an unnecessary portion of the photoresist is removed with an alkaline developer by a developing apparatus. And dissolve to reveal the desired pattern. Thereafter, the metal layer is etched by the RIE apparatus, the patterning is finished, and each electrode pattern constituting the surface acoustic wave device is obtained. Thereafter, a protective film and insulators 15 to 18 are formed on a predetermined region of the electrode. That is, a CVD (Chemical Vapor Deposition) apparatus is used to form a protective film and a SiO ₂ film as insulators 15 to 18 with a thickness of about 1.0 μm on each electrode pattern and piezoelectric substrate 1. Further, patterning is performed by photolithography, and the SiO ₂ film other than the insulators 15 to 18 is etched by an RIE apparatus or the like to adjust the film thickness to about 0.2 μm. Thereafter, using a sputtering apparatus, signal lead electrodes 19 to 22 are formed with an Al—Cu alloy. Thereby, a surface acoustic wave device having the cross wiring portions 23 to 26 is manufactured.

When a resin such as a polyimide resin is used as the insulators 15 to 18, for example, a SiO ₂ film serving as a protective film is formed on each electrode pattern and the piezoelectric substrate 1 with a thickness of about 0.01 μm, and the SiO ₂ A resin layer to be the insulators 15 to 18 is spin-coated on the film to a thickness of about 2 to 3 μm, patterned by photolithography, and the resin layers other than the insulators 15 to 18 are removed by an RIE apparatus or the like. Insulators 15 to 18 are formed by laminating the SiO ₂ film and the resin layer.

  FIG. 2 shows a plan view of another example of the embodiment of the electrode structure of the surface acoustic wave device of the present invention. As shown in FIG. 2, the surface acoustic wave device of the present invention has a long electrode finger in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate 1 on the piezoelectric substrate 1. A plurality of odd-numbered IDT electrodes 2 to 4 and 5 to 7 and a plurality of odd-numbered IDT electrodes 2 to 4 and 5 to 7 are arranged on both sides, and are long electrode fingers in a direction perpendicular to the propagation direction. Are formed, and first and second surface acoustic wave elements 31 and 32 having a plurality of reflector electrodes 8 to 11 are formed, and the first and second surface acoustic wave elements 31 and 32 are unbalanced signals. The surface acoustic wave resonators 34 and 35 connected to the balanced signal terminals 13 and 14 are connected to the subsequent stages of the first and second surface acoustic wave elements 31 and 32 and connected to the terminal 12. A surface acoustic wave device comprising first and second surface acoustic wave elements 31, 3 Grounding lead wires 27 and 28 connected to the bus bar electrodes on the IDT electrode surface acoustic wave resonators 34 and 35 side, the first and second surface acoustic wave elements 31 and 32, and the surface acoustic wave resonator 34, 35, the signal lead-out wirings 23 to 26 connected to each other form cross wiring portions 19 to 22 arranged so as to cross each other via insulators 15 to 18, respectively. 22 is formed symmetrically with respect to the IDT electrodes 3 and 6 disposed in the center in the odd number of IDT electrodes 2 to 4 and 5 to 7, and the resistance generated by the respective cross wiring portions 19 to 22. Are substantially the same.

  As a result, the current flowing through the wiring is substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Further, since the cross wiring portions 19 to 22 are formed symmetrically around the IDT electrodes 3 and 6 disposed in the center in the odd number of IDT electrodes 2 to 4 and 5 to 7, the surface acoustic wave device is provided. In the first surface acoustic wave element 31 and the second surface acoustic wave element 32, it is possible to finely and precisely adjust the resistance and the capacitance introduced in the equivalent circuit of the above, and the amplitude balance and the phase balance Can be improved.

  FIG. 3 shows a plan view of another example of the preferred embodiment of the electrode structure of the surface acoustic wave device of the present invention. As shown in FIG. 3, in the surface acoustic wave device of the present invention, in the configuration of FIG. 2, third and fourth surface acoustic wave elements 36 and 37 are further connected downstream of the surface acoustic wave resonators 34 and 35. The grounding lead wires 27a and 28a connected to the bus bar electrodes on the surface of the surface acoustic wave resonators 34 and 35 of the IDT electrodes of the third and fourth surface acoustic wave elements 36 and 37, and surface acoustic wave resonance All signal lead-out wirings 23a to 26a connecting the elements 34 and 35 to the third and fourth surface acoustic wave elements 36 and 37 are arranged to intersect with each other through the insulators 15a to 18a. Wiring portions 19a to 22a are respectively formed, and the cross wiring portions 19a to 22a are symmetrical with respect to the IDT electrodes 3a and 6a disposed at the center of the odd number of IDT electrodes 2a to 4a and 5a to 7a. Once formed In addition, since the resistance generated by each of the cross wiring portions 19a to 22a is substantially the same, the resistance and the capacitance in the cross wiring portions 19a to 22a can be made substantially the same as described above. The flowing currents are substantially the same, and the ripple in the passband can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Furthermore, the amount of attenuation outside the passband can be greatly reduced. In the third and fourth surface acoustic wave elements 36 and 37, 8a to 11a are reflector electrodes.

  FIG. 4 shows a plan view of another example of the embodiment of the electrode structure of the surface acoustic wave device of the present invention. As shown in FIG. 4, the surface acoustic wave device of the present invention has a long electrode finger on the piezoelectric substrate 1 along the direction of propagation of the surface acoustic wave propagating on the piezoelectric substrate 1 in a direction orthogonal to the propagation direction. A plurality of odd-numbered IDT electrodes 2 to 4 and 5 to 7 and a plurality of odd-numbered IDT electrodes 2 to 4 and 5 to 7 are arranged on both sides, and are long electrode fingers in a direction perpendicular to the propagation direction. Are formed, and first and second surface acoustic wave elements 31 and 32 having a plurality of reflector electrodes 8 to 11 are formed, and the first and second surface acoustic wave elements 31 and 32 are unbalanced signals. The third and fourth surface acoustic wave elements 36, 36 connected to the terminal 12 and connected to the balanced signal terminals 13, 14, respectively, on the subsequent stage of the first and second surface acoustic wave elements 31, 32. 37 is a surface acoustic wave device to which a first and a second are connected Grounding lead wires 27 and 28 connected to the third and fourth surface acoustic wave elements 36 and 37 of the IDT electrodes of the surface acoustic wave elements 31 and 32 and the third and fourth surface acoustic waves. Grounding lead lines 27a and 28a connected to the bus bar electrodes on the first and second surface acoustic wave elements 31 and 32 side of the IDT electrodes 2a to 7a of the elements 36 and 37, and the first and second surface acoustic waves. All the signal lead wires 23 to 26 connecting the devices 31 and 32 and the third and fourth surface acoustic wave devices 36 and 37 intersect with each other through the insulators 15 to 18 and 15a to 18a. Cross wiring portions 19 to 22 and 19a to 22a are formed, and the cross wiring portions 19 to 22 and 19a to 22a are formed by odd-numbered IDT electrodes 2 to 4 and 5 to 7 (2a to 4a and 5a, respectively). ~ 7a) in the middle Setting has been IDT electrode 3,6,3A, 6a together are symmetrically formed about the results from each of the intersecting wiring portion 19~22,19a~22a resistance is substantially the same. In the third and fourth surface acoustic wave elements 36 and 37, 8a to 11a are reflector electrodes.

  With the above configuration, as described above, the resistance and the capacitance of the cross wiring portions 19 to 22 and 19a to 22a can be made substantially the same, and the currents flowing through the wires are substantially the same, and thus within the passband. Ripple can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Furthermore, since the two-stage longitudinally coupled surface acoustic wave filters are connected in cascade, the amount of attenuation outside the passband can be greatly reduced.

  FIG. 5 shows a plan view of another example of the preferred embodiment of the electrode structure of the surface acoustic wave device of the present invention. As shown in FIG. 5, the first and second surface acoustic wave elements 31 and 32 are connected to the unbalanced signal terminal 12 via a surface acoustic wave resonator 38. As a result, the crossing width of the IDT electrodes of the surface acoustic wave element 38 can be reduced to half that of the conventional surface acoustic wave element, and the resistance loss can be reduced as compared with the conventional surface acoustic wave element. The insertion loss of the surface acoustic wave device can be improved. Further, since the first and second surface acoustic wave elements 31 and 32 are connected in parallel at the bus bar electrodes of the respective IDT electrodes via the surface acoustic wave resonator 38, compared with the conventional surface acoustic wave device. Therefore, the resistance loss can be reduced, so that the insertion loss of the surface acoustic wave device can be improved.

  FIG. 6 shows a plan view of another example of the embodiment of the electrode structure of the surface acoustic wave device of the present invention. As shown in FIG. 6, on the piezoelectric substrate 1, an odd number of 5 or more provided with a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate 1 Surface acoustic wave elements having IDT electrodes 51 to 55 and reflector electrodes 61 and 62 provided on both sides of odd number of IDT electrodes 51 to 55 and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction. The surface acoustic wave element 39 is a surface acoustic wave device connected to the unbalanced input terminal 12 and the unbalanced output terminal 13, and is an unbalanced input terminal of the IDT electrode of the surface acoustic wave element 39. The grounding lead wire 70 on the 12th side and all signal lead wires 44 to 46 connecting the surface acoustic wave element 39 and the unbalanced input terminal 12 intersect with each other through the insulators 41 to 43. Crossed wiring section 47 49, and the grounding lead wire 71 on the unbalanced output terminal 13 side of the IDT electrodes 51 to 55 of the surface acoustic wave element 39, and the surface acoustic wave element 39 and the unbalanced output terminal 13 are connected. All signal lead-out wirings 19 and 20 form cross wiring portions 23 and 24 that are arranged so as to cross each other via insulators 15 and 16, respectively. The cross wiring portions 23 and 24 are odd numbers. The IDT electrodes 51 to 55 are formed symmetrically around the IDT electrode 53 disposed in the center, and the resistances generated by the respective cross wiring portions 23, 24, 47 to 49 are substantially the same.

  With the above configuration, as described above, the resistance and capacitance of the cross wiring portions 23, 24, and 47 to 49 can be made substantially the same, and the currents flowing through the wiring are substantially the same, so that they are within the passband. Ripple can be greatly reduced. Therefore, it is possible to improve the insertion loss in the pass band. Further, since the surface acoustic wave element is configured by five or more IDT electrodes, the bandwidth in the pass band can be widened.

  In addition, this configuration eliminates the need for a ground pad electrode between the surface acoustic wave element and the terminal, and further enables the ground electrode to be integrated into one, reducing the device area as much as possible to reduce the surface acoustic wave. The apparatus can be miniaturized.

  In each figure, the number of electrode fingers such as IDT electrodes, reflector electrodes, surface acoustic wave elements, etc. ranges from several to several hundreds. For simplicity, these figures are simplified in the figure. ing.

  As the piezoelectric substrate 1 for the surface acoustic wave device, 36 ° ± 3 ° Y-cut X-propagation lithium tantalate single crystal, 42 ° ± 3 ° Y-cut X-propagation lithium tantalate single crystal, 64 ° ± 3 ° Y Cut X-propagating lithium niobate single crystal, 41 ° ± 3 ° Y-cut X-propagating lithium niobate single crystal, 45 ° ± 3 ° X-cut Z-propagating lithium tetraborate single crystal has a large electromechanical coupling coefficient and frequency Since the temperature coefficient is small, it is preferable as the piezoelectric substrate 1. Of these pyroelectric piezoelectric single crystals, if the piezoelectric substrate 1 has a significantly reduced pyroelectric property due to solid solution of oxygen defects or Fe, the reliability of the device is good. The thickness of the piezoelectric substrate 1 is preferably about 0.1 to 0.5 mm. If the thickness is less than 0.1 mm, the piezoelectric substrate 1 becomes brittle, and if it exceeds 0.5 mm, the material cost and component dimensions become large, which is not suitable for use.

  The IDT electrodes 2 to 7 and the reflector electrodes 8 to 11 are made of Al or an Al alloy (Al—Cu type, Al—Ti type) and are formed by a thin film forming method such as a vapor deposition method, a sputtering method, or a CVD method. To do. The electrode thickness is preferably about 0.1 to 0.5 μm for obtaining characteristics as a surface acoustic wave device (surface acoustic wave filter).

Furthermore, SiO ₂ , SiN _x , Si, Al ₂ O ₃ is formed as a protective film on each electrode of the surface acoustic wave device according to the present invention and the surface acoustic wave propagating portion on the piezoelectric substrate 1 to form a conductive foreign matter. It is also possible to prevent energization and improve power durability.

  In addition, the surface acoustic wave device of the present invention can be applied to a communication device. That is, at least one of a receiving circuit and a transmitting circuit is provided and used as a bandpass filter included in these circuits. For example, the transmission signal output from the transmission circuit is put on the carrier frequency by the mixer, the unnecessary signal is attenuated by the band pass filter, and then the transmission signal is amplified by the power amplifier and transmitted from the antenna through the duplexer. A communication device equipped with a transmission circuit capable of receiving signals or receiving a received signal with an antenna, amplifying the received signal that has passed through the duplexer with a low-noise amplifier, and then attenuating an unnecessary signal with a band-pass filter, and a carrier frequency with a mixer Can be applied to a communication apparatus including a receiving circuit that separates a signal from the signal and transmits the signal to a receiving circuit that extracts the signal. Accordingly, when the surface acoustic wave device of the present invention is employed, the insertion loss of the surface acoustic wave device is improved, and therefore an excellent communication device with reduced power consumption and remarkably good sensitivity can be provided.

  In the description of the above-described embodiment, for the sake of simplicity, there are many electrode fingers that are long in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate 3. Although an example in which two IDT electrodes are arranged has been shown, the present invention is not limited to this, and an odd number of five or more IDT electrodes may be arranged, and the gist of the present invention is also possible in other configurations. It is possible to make appropriate changes without departing from the scope.

It is a top view which shows one example of embodiment about the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of embodiment about the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of embodiment about the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of embodiment about the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of embodiment about the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of embodiment about the surface acoustic wave apparatus of this invention. It is a top view which shows typically the example of an electrode structure of the conventional surface acoustic wave apparatus.

Explanation of symbols

1: Piezoelectric substrate 2-7: IDT electrodes 8-11: Reflector electrode 12: Unbalanced signal terminal (unbalanced input (out) force terminal)
13, 14: balanced signal terminal (balanced output (input) force terminal)
15-18: Insulators 19-22: Signal lead-out wiring 27, 28: Ground lead-out wiring 31: First surface acoustic wave element 32: Second surface acoustic wave element 36: Third surface acoustic wave element 37 : Fourth surface acoustic wave elements 34, 35, 38: surface acoustic wave resonators

Claims (7)

On the piezoelectric substrate, three or more odd IDT electrodes each having a plurality of long electrode fingers in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate, and the odd number First and second surface acoustic wave elements having reflector electrodes each provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction are formed on both sides of each IDT electrode,
The first and second surface acoustic wave elements are surface acoustic wave devices connected to an unbalanced signal terminal and each connected to a balanced signal terminal,
Grounding lead lines connected to the bus bar electrodes on the balanced signal terminal side of the IDT electrodes of the first and second surface acoustic wave elements, the first and second surface acoustic wave elements, and the balanced signal terminals And all signal lead wires connected to each other form a cross wiring portion arranged to cross each other via an insulator,
The cross wiring portion is formed symmetrically around an IDT electrode disposed in the center of the odd number of IDT electrodes, and the resistance generated by each cross wiring portion is substantially the same. A surface acoustic wave device. Three or more odd IDT electrodes each having a plurality of long electrode fingers in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate on the piezoelectric substrate, and the odd number First and second surface acoustic wave elements having reflector electrodes each provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction are formed on both sides of each IDT electrode,
The first and second surface acoustic wave elements are connected to an unbalanced signal terminal, and the surface acoustic wave resonance is connected to the balanced signal terminal at each subsequent stage of the first and second surface acoustic wave elements. A surface acoustic wave device to which a child is connected,
Grounding lead wires connected to the bus bar electrodes on the surface acoustic wave resonator side of the IDT electrodes of the first and second surface acoustic wave elements, the first and second surface acoustic wave elements, and the elasticity All the signal lead wires connected to the surface wave resonators form cross wiring portions arranged to cross each other through an insulator,
The cross wiring portion is formed symmetrically around an IDT electrode disposed in the center of the odd number of IDT electrodes, and the resistance generated by each cross wiring portion is substantially the same. A surface acoustic wave device. Third and fourth surface acoustic wave elements are connected to the subsequent stage of the surface acoustic wave resonator, and the surface acoustic wave resonator side of the IDT electrode of the third and fourth surface acoustic wave elements The ground lead wire connected to the bus bar electrode and all signal lead wires connecting the surface acoustic wave resonator and the third and fourth surface acoustic wave elements intersect via an insulator. Each of which is formed as a cross wiring portion,
The cross wiring portion is formed symmetrically around an IDT electrode disposed in the center of the odd number of IDT electrodes, and the resistance generated by each cross wiring portion is substantially the same. The surface acoustic wave device according to claim 2. On the piezoelectric substrate, three or more odd IDT electrodes each having a plurality of long electrode fingers in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate, and the odd number First and second surface acoustic wave elements having reflector electrodes each provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction are formed on both sides of each IDT electrode,
The first and second surface acoustic wave elements are connected to an unbalanced signal terminal, and a third stage connected to the balanced signal terminal at each subsequent stage of the first and second surface acoustic wave elements. And a surface acoustic wave device to which a fourth surface acoustic wave element is connected,
Grounding lead lines connected to the bus bar electrodes on the third and fourth surface acoustic wave element sides of the IDT electrodes of the first and second surface acoustic wave elements, and the third and fourth elastic surfaces Grounding lead wires connected to the bus bar electrodes on the first and second surface acoustic wave resonator sides of the IDT electrode of the wave element, the first and second surface acoustic wave elements, and the third and third All the signal lead-out wirings connected to the surface acoustic wave elements of 4 form cross wiring portions arranged so as to cross each other through an insulator,
The cross wiring portion is formed symmetrically around an IDT electrode disposed in the center of the odd number of IDT electrodes, and the resistance generated by each cross wiring portion is substantially the same. A surface acoustic wave device.   5. The surface acoustic wave device according to claim 1, wherein the first and second surface acoustic wave elements are connected to the unbalanced signal terminal via a surface acoustic wave resonator. 6. . On the piezoelectric substrate, along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate, five or more odd-numbered IDT electrodes having a plurality of long electrode fingers in the direction orthogonal to the propagation direction, and the odd number A surface acoustic wave element having a reflector electrode provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction is formed on each side of each IDT electrode,
The surface acoustic wave element is a surface acoustic wave device connected to an unbalanced input terminal and an unbalanced output terminal,
The grounding lead wire on the unbalanced input terminal side of the IDT electrode of the surface acoustic wave element and all the signal lead wires connecting the surface acoustic wave element and the unbalanced input terminal have an insulator. Crossing wiring portions arranged to cross each other, grounding lead wirings on the unbalanced output terminal side of the IDT electrode of the surface acoustic wave element, the surface acoustic wave element, and the surface acoustic wave element All signal lead wires connected to the unbalanced output terminal form cross wiring portions arranged to cross each other via an insulator,
The cross wiring portion is formed symmetrically around an IDT electrode disposed in the center of the odd number of IDT electrodes, and the resistance generated by each cross wiring portion is substantially the same. A surface acoustic wave device. A communication apparatus comprising at least one of a receiving circuit and a transmitting circuit having the surface acoustic wave device according to claim 1.

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