JP5115184B2 - Boundary acoustic wave device, filter using the same, and antenna duplexer - Google Patents

Description

  The present invention relates to a boundary acoustic wave device, a filter using the same, and an antenna duplexer.

  Conventionally, in this type of boundary acoustic wave device, a comb-shaped electrode is disposed at the interface of different media, and the boundary acoustic wave propagates through the interface. Therefore, the vibration space of the surface acoustic wave is formed compared to the surface acoustic wave device. There is an advantage that the package structure can be simplified, reduced in size and reduced in height easily without being required. For example, Patent Document 1 is known as an example of this type of boundary acoustic wave device.

  On the other hand, when this type of boundary acoustic wave device is configured, there is a problem that spurious due to the transverse mode occurs and the characteristics of the boundary acoustic wave device deteriorate. As a method for suppressing such deterioration of the characteristics of the boundary acoustic wave device, there has been proposed a method for improving the characteristics by applying an apodization weighting with a specific gap provided between the electrode fingers of the comb electrode and the dummy electrode. (For example, patent document 2).

FIG. 8 shows a configuration of a conventional boundary acoustic wave device. 8A is a top view of the boundary acoustic wave device, and FIG. 8B is a cross-sectional view taken along line GG ′. A comb electrode 1202 and a reflector electrode 1203 are formed on the first medium 1201, and a second medium 1204 is formed thereon. Here, the comb-shaped electrode 1202 is subjected to the apodization weighting in which a specific gap is provided between the electrode finger of the comb-shaped electrode and the dummy electrode in order to suppress characteristic deterioration.
JP 58-83420 A JP 2006-319887 A

  However, when the comb-shaped electrode is subjected to apodization weighting as in the conventional boundary acoustic wave device described above, the Q value is deteriorated, and as a result, the insertion loss and the attenuation characteristic are deteriorated. .

  Accordingly, an object of the present invention is to improve insertion loss and attenuation characteristics without increasing the size of the boundary acoustic wave device.

  In order to achieve the above object, the present invention includes a first medium made of a piezoelectric material, a comb electrode provided on an upper surface of the first medium, and a second medium covering the comb electrode. In the boundary acoustic wave device, the comb-shaped electrode includes a bus bar electrode region, a dummy electrode region, and a crossing region, and at least above either the bus bar electrode region or the dummy electrode region, The second medium is in a non-formed state.

  According to this configuration, by making the sound velocity of the wave in the bus bar electrode region or the dummy electrode region faster than the sound velocity of the wave in the intersecting region, elasticity to the bus bar electrode region or the dummy electrode region is achieved. It is possible to suppress the leakage of the boundary wave in the lateral direction, and the insertion loss and the attenuation characteristic can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a boundary acoustic wave device according to Embodiment 1 of the present invention. 1A is a configuration diagram of a boundary acoustic wave device, and FIG. 1B is a cross-sectional view taken along line AA ′. A comb electrode 102 and a reflector electrode 103 made of a metal mainly composed of Al are formed on the first medium 101, and a second medium 104 made of SiO ₂ is formed thereon. The comb electrode 102 includes a bus bar electrode region 105, a dummy electrode region 106, and a crossing region 107. Here, the dummy electrode region 106 indicates a region of the length of the dummy electrode in the comb electrode 102, and the intersecting region 107 indicates a region of the length where the comb electrode 102 intersects. Further, the upper portion of the bus bar electrode region 105 of the comb electrode 102 is configured such that the second medium 104 is removed.

  In the configuration as described above, the second medium 104 is not formed in the upper portion of the bus bar electrode region 105, and the sound velocity of the wave in the bus bar electrode region 105 is made faster than the sound velocity of the wave in the intersection region 107. Thus, it is possible to suppress the lateral leakage of the boundary acoustic wave in the intersecting region 107. As a result, the characteristics of the boundary acoustic wave device can be improved, and an excellent boundary acoustic wave device can be realized.

  In the present embodiment, a boundary acoustic wave device having wideband characteristics can be realized by using a rotating Y-plate lithium niobate substrate of −30 degrees to +30 degrees as the first medium 101. it can.

  In the present embodiment, the configuration in which the second medium 104 is not formed in the upper portion of the bus bar electrode region 105 in the comb electrode 102 has been described. However, this configuration is as illustrated in FIG. May be. FIG. 2 is a diagram showing another configuration of the boundary acoustic wave device according to the present embodiment. 2A is a configuration diagram of a boundary acoustic wave device, and FIG. 2B is a cross-sectional view of B-B ′. 1 is that the second medium 104 is not formed above the dummy electrode region 106 in the comb electrode 102 of the boundary acoustic wave device. As described above, the same effect can be obtained even when the second medium 104 is not formed in the upper portion of the dummy electrode region 106. Moreover, the structure of a boundary acoustic wave device as shown in FIG. 3 may be used. 3A is a configuration diagram of a boundary acoustic wave device, and FIG. 3B is a cross-sectional view of C-C ′. As described above, the region from which the second medium 104 is removed may be applied to the region between the dummy electrode region 106 and the intersecting region 107 of the comb electrode 102.

  Note that in this embodiment mode, the second medium 104 is not formed in the upper portion of the bus bar electrode region 105 and the dummy electrode region 106 in the comb-shaped electrode 102. Is not limited to this, and may be at least a part of the bus bar electrode region 105 or the dummy electrode region 106.

  Note that in this embodiment mode, the second medium 104 is not formed over the entire upper surface of the bus bar electrode region 105 or the dummy electrode region 106 in the comb-shaped electrode 102. The second medium 104 in the upper part of the bus bar electrode region 105 may be thinner than the second medium 104 in the upper part of the intersecting region 107, and the upper part of the intersecting region 107 of the boundary acoustic wave device may be used. And the upper part of the bus bar electrode region 105 or the dummy electrode region 106 are changed so that the acoustic velocity of the elastic boundary wave in the bus bar electrode region 105 in the boundary acoustic wave device is higher than the acoustic velocity of the wave in the intersecting region. As long as the configuration is possible, the same effect as the present invention can be obtained.

  The electrode material is mainly Al, but in this case, since the processability is excellent, the dimensional variation of the comb electrode 102 can be reduced, and as a result, a boundary acoustic wave device with small frequency variation is obtained. It is done. However, the present invention is not limited to this, and other conductive materials such as Cu, Au, Ta, W, Ag, Pt, and ITO may be used.

Although the second medium 104 is made of SiO ₂ , in this case, since it has a temperature coefficient opposite to that of the lithium niobate of the first medium 101, a boundary acoustic wave device having excellent temperature characteristics can be obtained. However, the present invention is not limited to this, and other dielectric materials such as Ta ₂ O ₅ , TeO ₂ , and Ti ₃ O ₅ may be used. The second medium 104 is formed by using a thin film forming method such as sputtering, P-CVD, spin coating, and the like. Further, the bus bar electrode region 105 in the comb electrode 102 is formed by using a wet etching method or a dry etching method. The second medium 104 above the dummy electrode region 106 can be removed as appropriate to make it non-formed.

  Further, the configuration of the reflector electrode 103 is not limited to this, and in the upper part of the region corresponding to the bus bar electrode region 105 of the reflector electrode 103 and the dummy electrode region 106 of the comb electrode 102, the second A configuration in which the medium 104 is not formed or thinned may be employed.

(Embodiment 2)
FIG. 4 is a diagram showing a configuration of a boundary acoustic wave device according to Embodiment 2 of the present invention. 4A is a top view of the boundary acoustic wave device, and FIG. 4B is a cross-sectional view taken along the line DD ′ in FIG. A comb electrode 102 and a reflector electrode 103 made of a metal mainly composed of Al are formed on the first medium 101, and a second medium 104 made of SiO ₂ is formed thereon. The comb electrode 102 includes a bus bar electrode region 105, a dummy electrode region 106, and a crossing region 107. Here, the dummy electrode region 106 indicates a region of the length of the dummy electrode in the comb-shaped electrode 102, and the intersecting region 107 indicates a region of the length where the comb-shaped electrode intersects. Further, the second medium 104 made of SiO ₂ is removed from the upper portion of the bus bar electrode region 105 of the comb electrode 102. The difference from the boundary acoustic wave device of the first embodiment is that the upper part of the second medium 104 made of SiO ₂ is covered with a third medium 108. At this time, as a material constituting the third medium 108, SiN that is faster than the sound velocity of the transverse wave in the second medium 104 made of SiO ₂ is used in the present embodiment. With such a configuration, the confinement property of the boundary acoustic wave propagated at the boundary between the first medium 101 and the second medium 104 is improved, and a boundary acoustic wave device with a smaller insertion loss can be obtained. .

  Also in the present embodiment, a boundary acoustic wave device having a wideband characteristic can be realized by using a rotating Y-plate lithium niobate substrate of −30 degrees to +30 degrees as the first medium 101. it can.

In the boundary acoustic wave device according to Embodiment 2 of the present invention, SiN is used as the material constituting the third medium 108, but the material is not limited to this, and a material such as SiON, DLC, AlN, or the like, or These laminates may be used, and the same effect can be obtained by selecting a material having a sound velocity of transverse waves faster than that of SiO ₂ . Further, when another material having a transverse sound velocity slower than that of SiO ₂ is selected for the second medium 104, the same effect can be obtained even if SiO ₂ is selected as the third medium 108.

  In the second embodiment, as in the first embodiment, the second medium 104 is not formed on the entire upper surface of the bus bar electrode region 105 of the comb-shaped electrode. The configuration is not limited to the above, and the second medium 104 above the bus bar electrode region 105 is thinner than the second medium 104 above the intersecting region 107. Further, the bus bar electrode region 105 in the comb electrode, or The second medium 104 in a part of the dummy electrode region 106 may be removed, or the second medium 104 may be thin.

  Alternatively, the second medium 104 above the bus bar electrode region 105 and the dummy electrode region 106 may be completely removed, or the second medium 104 at either one of the upper portions may be removed. Even if the region to be removed is applied to the region between the dummy electrode region 106 and the intersecting region 107 of the comb electrode 102, the same effect as in the present invention can be obtained.

  Similarly, the electrode material is a metal material mainly composed of Al, but is not limited thereto, and other conductive materials such as Cu, Au, Ta, W, Ag, Pt, ITO, etc. May be used.

  In addition, the configuration of the reflector electrode 103 is not limited to this, and the second medium above the regions corresponding to the bus bar electrode region 105 of the reflector electrode 103 and the dummy electrode region 106 of the comb electrode 102. The configuration may be such that 104 is removed or made thinner.

(Embodiment 3)
FIG. 5 is a diagram showing a configuration of a boundary acoustic wave device according to Embodiment 3 of the present invention. 5A is a configuration diagram of the boundary acoustic wave device, and FIG. 5B is a cross-sectional view taken along line EE ′ of FIG. A comb electrode 102 and a reflector electrode 103 made of a metal mainly composed of Al are formed on the first medium 101, and a second medium 104 made of SiO ₂ is formed on the comb electrode 102 and the reflector electrode 103. A third medium 108 made of SiN is formed on the medium 104. The comb electrode 102 includes a bus bar electrode region 105, a dummy electrode region 106, and a crossing region 107. Here, the dummy electrode region 106 indicates a region of the length of the dummy electrode in the comb-shaped electrode 102, and the intersecting region 107 indicates a region of the length where the comb-shaped electrode intersects. Further, the second medium 104 is removed from the upper portion of the bus bar electrode region 105 of the comb-shaped electrode 102 so as not to be formed. The difference from the boundary acoustic wave device according to the second embodiment is that, in the upper portion of the bus bar electrode region 105, the portion where the second medium 104 is not formed has a sound velocity of the transverse wave higher than the sound velocity of the transverse wave in the second medium. This is a configuration that is covered with a fast fourth medium 109.

  Note that in this embodiment mode, SiN, which is the same material as the third medium, is used as a material constituting the fourth medium 109 and is formed simultaneously with the third medium 108.

  As described above, the second medium 104 is not formed in the upper portion of the bus bar electrode region 105, and the portion where the second medium 104 is not formed in the upper portion of the bus bar electrode region 105 is the second portion. By covering with the fourth medium 109 having a higher sound speed than the medium 104, the difference in the sound speed between the bus bar electrode region 105 and the intersecting region 107 is further increased, and the elastic boundary wave toward the bus bar electrode region 105 is laterally moved. As a result, the characteristics of the boundary acoustic wave device can be further improved.

  Also in the third embodiment, a boundary acoustic wave device having a wideband characteristic is realized by using a rotating Y-plate lithium niobate substrate of −30 degrees to +30 degrees as the first medium 101. Can do.

In the boundary acoustic wave device according to Embodiment 3 of the present invention, the fourth medium 109 is made of the same material as that of the third medium 108, but is not limited to this, and the third medium 108 is not limited thereto. Different materials may be used. Further, SiN is used as a material constituting the fourth medium 109, but the material is not limited to this. For example, a material such as SiON, DLC, AlN, or a laminate thereof may be used. The same effect can be obtained by selecting a material having a shear wave speed higher than that of SiO ₂ of the medium 104. Further, when another material having a transverse wave velocity slower than that of SiO ₂ is selected for the second medium 104, the same effect can be obtained even if SiO ₂ is selected as the fourth medium layer 109.

  In the third embodiment, as in the first embodiment, the second medium 104 is not formed on the entire upper surface of the bus bar electrode region 105 in the comb electrode 102. The configuration is not limited to this, and the second medium 104 above the bus bar electrode region 105 is thinner than the second medium 104 above the intersecting region 107, and further, the bus bar electrode region 105 in the comb-shaped electrode, Alternatively, the second medium 104 in a part of the dummy electrode region 106 may be removed, or the second medium 104 may be thin. Alternatively, the second medium 104 above the bus bar electrode region 105 and the dummy electrode region 106 may be completely removed, or the second medium 104 at either one of the upper portions may be removed. Even if the region to be removed is applied to the region between the dummy electrode region 106 and the intersecting region 107 of the comb electrode 102, the same effect as in the present invention can be obtained.

  Similarly, the electrode material is a metal material mainly composed of Al, but is not limited thereto, and other conductive materials such as Cu, Au, Ta, W, Ag, Pt, ITO, etc. May be used.

  In addition, the configuration of the reflector electrode 103 is not limited to this, and the second medium above the regions corresponding to the bus bar electrode region 105 of the reflector electrode 103 and the dummy electrode region 106 of the comb electrode 102. The configuration may be such that 104 is removed or made thinner.

(Embodiment 4)
FIG. 6 is a diagram showing a configuration of a boundary acoustic wave device according to Embodiment 4 of the present invention. 6A is a configuration diagram of a boundary acoustic wave device, and FIG. 6B is a cross-sectional view of FF ′ in FIG. A comb-shaped electrode 702 and a reflector electrode 703 made of a material containing Al as a main component are formed on a first medium 701, and a second medium 704 made of SiO ₂ is formed thereon. The comb electrode 702 includes a bus bar electrode region 705, a dummy electrode region 706, and an intersecting region 707, and has a regular comb electrode configuration. Here, the dummy electrode region 706 indicates the minimum length region of the dummy electrode in the comb electrode 702, and the intersection region 707 indicates the maximum length region where the comb electrode intersects. The dummy electrode region 705 includes metallized dummy electrode weighting, and is metallized from the center toward the outside so that the length of the dummy electrode is gradually shortened. Further, the second medium 704 is not formed on the bus bar electrode region 705 and the dummy electrode region 706 of the comb electrode 702.

  As described above, in the boundary acoustic wave device according to the fourth embodiment, the second medium 704 is not formed in the upper portion of the dummy electrode region, so that the surface acoustic wave busbar electrode in the boundary acoustic wave device is obtained. In addition to the effect that the spurious due to the transverse mode can be suppressed by suppressing the lateral leakage to the dummy electrode region 706 by making the sound velocity of the region 705 higher than the sound velocity of the intersecting region, The effect of improving the characteristics can be obtained. In addition, as shown in the conventional example, by suppressing the spurious due to the transverse mode with the normal comb-shaped electrode configuration without applying the apodization weighting, the deterioration of the resonator characteristics such as the Q value due to the apodization weighting is prevented. Thus, the structure is further advantageous in terms of characteristics in realizing the boundary acoustic wave device. Furthermore, when realizing the same capacitance as the boundary acoustic wave device, the boundary acoustic wave device of the present invention can be made smaller in resonator size than the conventional boundary-weighted boundary acoustic wave device. Also, an effect that the boundary acoustic wave device can be reduced in size can be obtained.

  As described above, the boundary acoustic wave device of the present invention improves the characteristics of the boundary acoustic wave device by weighting the dummy electrode region 706 of the comb-shaped electrode and further removing the second medium 704 above the dummy electrode region 706. And an excellent boundary acoustic wave device can be realized.

  In the fourth embodiment as well, a boundary acoustic wave device having broadband characteristics can be realized by using a rotating Y-plate lithium niobate substrate of −30 degrees to +30 degrees as the first medium. it can.

  In the fourth embodiment, the configuration in which the second medium 704 is not formed in the upper part of the dummy electrode region 706 in the comb-shaped electrode has been described. However, this corresponds to the dummy electrode region 706 and the bus bar electrode region. A configuration in which the second medium 704 is not formed on both upper portions of 705 may be employed.

  In addition, although the configuration in which all of the second medium 704 is removed is described, this configuration is not limited to this, and the upper portion of the dummy electrode region 706 is higher than the second medium 704 in the upper portion of the intersecting region 707. The second medium 704 may have a thin configuration, and the configuration of the upper portion of the crossing region 707 and the upper portion of the dummy electrode region 706 of the boundary acoustic wave device is changed to change the wave of the dummy electrode region 706 in the boundary acoustic wave device. Any sound speed may be used as long as the sound speed can be made faster than the sound speed of the waves in the intersection region 707.

  In addition, the second medium 704 is not formed in the upper portion of all the regions in the dummy electrode region 706. However, this may be at least a part of the region. That is, the same effect as that of the present invention can be obtained if the second medium 704 is not formed in a part of the upper portion of the dummy electrode region 706 or the second medium 704 is thin.

  In addition to the dummy electrode region 706, the second medium 704 is not formed or the second medium 704 is thin in a part of the comb electrode in the upper part of the bus bar electrode region 705. It doesn't matter.

  In addition, the dummy weighting shape is metallized from the center toward the outside, and the length of the dummy electrode is gradually shortened. However, the present invention is not limited to this. If the medium 704 is in a non-formed state or the second medium 704 is thin, the same effect as the present invention can be obtained.

  In the fourth embodiment, similarly to the second embodiment, a third medium having a transverse wave speed higher than the transverse wave velocity in the second medium 704 is formed on the second medium 704. It may be. Further, as in the third embodiment, the area where the second medium 704 is not formed or the portion including the area where the second medium 704 is thinned is faster than the sound velocity of the transverse wave in the second medium 704. The structure covered with the 4th medium layer may be sufficient.

  The electrode material is a metal material mainly composed of Al, but is not limited thereto, and other conductive materials such as Cu, Au, Ta, W, Ag, Pt, and ITO are used. It doesn't matter.

In addition, the structure using SiO ₂ as the second medium 704 has been described, but other materials such as Ta ₂ O ₅ , TeO ₂ , and Ti ₃ O ₅ may be used.

  Further, the configuration of the reflector electrode 103 is not limited to this, and in the upper part of the region corresponding to the bus bar electrode region 105 of the reflector electrode 103 and the dummy electrode region 106 of the comb electrode 102, the second A configuration in which the medium 104 is not formed or thinned may be employed.

(Embodiment 5)
FIG. 7 is a diagram showing a configuration of a boundary acoustic wave device according to Embodiment 5 of the present invention. In FIG. 7, reference numerals 1101, 1102, 1103, and 1104 denote boundary acoustic wave devices with series arms, and reference numerals 1105 and 1106 denote boundary acoustic wave devices with parallel arms. Here, the boundary acoustic wave devices 1101, 1102, 1103, 1104, 1105, and 1106 are any of the boundary acoustic wave devices shown in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment. Constructed using. With the above configuration, a ladder-type boundary acoustic wave filter having excellent characteristics can be realized.

  In this embodiment, a ladder-type boundary acoustic wave filter using six boundary acoustic wave devices has been described. However, the number and configuration of boundary acoustic wave devices are not limited to this, and the boundary between the boundary acoustic wave devices is not limited. The boundary acoustic wave device having any one of the configurations shown in the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment is applied to at least one of the boundary acoustic wave devices constituting the wave filter. If this is the case, an improvement effect can be obtained.

  Moreover, not only in a ladder-type boundary acoustic wave filter by a boundary acoustic wave device in which reflector electrodes are arranged on both sides of the comb-shaped electrode, but also in a longitudinal mode type filter configured by arranging a plurality of comb-shaped electrodes close to each other, If the configuration of the comb electrode in any one of Embodiment 1, Embodiment 2, Embodiment 3, and Embodiment 4 is applied, an improvement effect can be obtained.

  In addition, the present invention achieves the same effect as the present invention even when applied to the boundary acoustic wave device constituting the antenna duplexer as well as the boundary acoustic wave filter, and realizes the antenna duplexer having excellent characteristics. be able to.

  The boundary acoustic wave device according to the present invention has the effect of improving the lateral leakage of the boundary acoustic wave and improving insertion loss and attenuation characteristics, and is useful in various electronic devices such as mobile phones. .

It is a figure which shows the structure of the boundary acoustic wave device in Embodiment 1, (a) The block diagram of a boundary acoustic wave device, (b) Sectional drawing of A-A ' It is a figure which shows the other structure of the boundary acoustic wave device in Embodiment 1, (a) Other structural drawing of a boundary acoustic wave device, (b) Sectional drawing of B-B ' It is a figure which shows the other structure of the boundary acoustic wave device in Embodiment 1, (a) Other structural drawing of a boundary acoustic wave device, (b) Sectional drawing of C-C ' It is a figure which shows the structure of the boundary acoustic wave device in Embodiment 2, (a) The block diagram of a boundary acoustic wave device, (b) Sectional drawing of D-D ' It is a figure which shows the structure of the boundary acoustic wave device in Embodiment 3, (a) The block diagram of a boundary acoustic wave device, (b) Sectional drawing of E-E ' It is a figure which shows the structure of the boundary acoustic wave device in Embodiment 4, (a) The block diagram of a boundary acoustic wave device, (b) Sectional drawing of F-F ' The figure which shows the structure of the boundary acoustic wave device in Embodiment 5. It is a figure which shows the structure of the conventional boundary acoustic wave device, (a) The block diagram of the conventional boundary acoustic wave device, (b) Sectional drawing of G-G '

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 1st medium 102 Comb-shaped electrode 103 Reflector electrode 104 2nd medium 105 Bus-bar electrode area | region 106 Dummy electrode area | region 107 Intersection area | region 108 3rd medium 109 4th medium 701 1st medium 702 Comb-shaped electrode 703 Reflection Electrode 704 Second medium 705 Bus bar electrode region 706 Dummy electrode region 707 Intersection region 1101 Boundary wave device 1102 Boundary wave device 1103 Boundary wave device 1104 Boundary wave device 1105 Boundary wave device 1106 Boundary wave device 1201 First 1 medium 1202 comb-shaped electrode 1203 reflector electrode 1204 second medium

Claims (12)

A boundary acoustic wave device comprising: a first medium made of a piezoelectric material; a comb electrode provided on an upper surface of the first medium; and a second medium covering the comb electrode;
The comb electrode includes a bus bar electrode region, a dummy electrode region, and a crossing region,
A boundary acoustic wave device in which the second medium is not formed at least in an upper portion of either the bus bar electrode region or the dummy electrode region. The boundary acoustic wave device according to claim 1, wherein the first medium is a lithium niobate substrate. The boundary acoustic wave device according to claim 2, wherein the lithium niobate substrate is a -30 to +30 degree rotated Y plate. The boundary acoustic wave device according to any one of claims 1 to 3, wherein the second medium is made of SiO ₂ . The boundary acoustic wave device according to any one of claims 1 to 4, wherein a third medium is provided above the second medium. The boundary acoustic wave device according to claim 5, wherein the third medium has a sound velocity of a transverse wave faster than a sound velocity of a transverse wave in the second medium. 7. The fourth medium according to claim 1, further comprising a fourth medium that covers at least a part of a region in which the second medium is not formed on the bus bar electrode region or the dummy electrode region. A boundary acoustic wave device according to claim 1. The boundary acoustic wave device according to claim 7, wherein the third medium and the fourth medium are the same medium. The boundary acoustic wave device according to any one of claims 1 to 8, wherein the dummy electrode region includes a metallized dummy electrode weighting. The boundary acoustic wave device according to claim 9, wherein the comb electrode has a regular comb electrode configuration. A filter having a plurality of resonators,
The filter which is a boundary acoustic wave device according to any one of claims 1 to 10, wherein at least one of the resonators. An antenna duplexer having a transmission filter and a reception filter,
As the transmission filter and / or the reception filter,
An antenna duplexer using the filter according to claim 11.

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