WO2008038502A1 - Filtre d'onde acoustique d'interface - Google Patents
Filtre d'onde acoustique d'interface Download PDFInfo
- Publication number
- WO2008038502A1 WO2008038502A1 PCT/JP2007/067322 JP2007067322W WO2008038502A1 WO 2008038502 A1 WO2008038502 A1 WO 2008038502A1 JP 2007067322 W JP2007067322 W JP 2007067322W WO 2008038502 A1 WO2008038502 A1 WO 2008038502A1
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- WIPO (PCT)
- Prior art keywords
- acoustic wave
- boundary acoustic
- wave filter
- idt
- longitudinally coupled
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/0222—Details of interface-acoustic, boundary, pseudo-acoustic or Stonely wave devices
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/0023—Balance-unbalance or balance-balance networks
- H03H9/0028—Balance-unbalance or balance-balance networks using surface acoustic wave devices
- H03H9/0033—Balance-unbalance or balance-balance networks using surface acoustic wave devices having one acoustic track only
- H03H9/0038—Balance-unbalance or balance-balance networks using surface acoustic wave devices having one acoustic track only the balanced terminals being on the same side of the track
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/0023—Balance-unbalance or balance-balance networks
- H03H9/0028—Balance-unbalance or balance-balance networks using surface acoustic wave devices
- H03H9/0047—Balance-unbalance or balance-balance networks using surface acoustic wave devices having two acoustic tracks
- H03H9/0066—Balance-unbalance or balance-balance networks using surface acoustic wave devices having two acoustic tracks being electrically parallel
- H03H9/0071—Balance-unbalance or balance-balance networks using surface acoustic wave devices having two acoustic tracks being electrically parallel the balanced terminals being on the same side of the tracks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/0023—Balance-unbalance or balance-balance networks
- H03H9/0028—Balance-unbalance or balance-balance networks using surface acoustic wave devices
- H03H9/0085—Balance-unbalance or balance-balance networks using surface acoustic wave devices having four acoustic tracks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
- H03H9/14544—Transducers of particular shape or position
- H03H9/14576—Transducers whereby only the last fingers have different characteristics with respect to the other fingers, e.g. different shape, thickness or material, split finger
- H03H9/14582—Transducers whereby only the last fingers have different characteristics with respect to the other fingers, e.g. different shape, thickness or material, split finger the last fingers having a different pitch
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
- H03H9/14544—Transducers of particular shape or position
- H03H9/14588—Horizontally-split transducers
Definitions
- the present invention relates to a boundary acoustic wave filter device used for, for example, a bandpass filter of a mobile phone, and more specifically, a longitudinally coupled resonator type elastic boundary in which a plurality of IDTs are arranged in a boundary acoustic wave propagation direction.
- the present invention relates to a wave filter device.
- Patent Document 1 discloses a surface acoustic wave filter device having the electrode structure shown in FIG.
- a surface acoustic wave filter device 1001 shown in FIG. 7 has a piezoelectric substrate 1002. Piezoelectric substrate 1002.
- the first and second longitudinally coupled resonator type surface acoustic wave filter sections 1011 and 1012 are configured by forming the illustrated electrode structure on 1002.
- the first IDT 1014 is disposed in the center
- the second and third IDTs 1013 and 1015 are disposed on both sides of the surface wave propagation direction of the first IDT.
- Reflectors 1016 and 1017 are arranged on both sides of the surface wave propagation direction of the region where IDTs 1013 to 1015 are arranged.
- the second and third IDTs 1018, 1020 force are provided on both sides of the surface wave propagation direction of the first IDT 1019 disposed in the center.
- S is arranged, and reflectors 1021 and 1022 are arranged on both sides of a region where IDTs 1018 to 1020 are provided.
- An input terminal is connected to one end of the first IDT 1014 of the first longitudinally coupled resonator type surface acoustic wave filter unit 1011.
- each of the IDTs 1013 and 1015 is connected to one end of each of the second and third IDTs 1018 and 1020 of the second longitudinally coupled resonator type surface acoustic wave filter unit 1012 by a signal line.
- One end of the first IDT 1019 at the center of the second longitudinally coupled resonator type surface acoustic wave filter unit 1012 is connected to the output terminal.
- IDT1013 to 1015 and IDT1018 to 1020 are connected to the above input terminal, output terminal and signal line! /, And the other end is connected to the ground potential.
- each IDT is provided with a narrow pitch electrode finger.
- the electrode finger pitch of the part including electrode finger 1013a located at the end of IDT 1013 on the IDT 1014 side and electrode finger 1013b arranged just inside electrode finger 1013a is relatively narrow. Accordingly, a narrow pitch electrode finger portion is formed.
- the electrode finger pitch of the narrow pitch electrode finger portion is smaller than the electrode finger pitch of the electrode finger portions other than the narrow pitch electrode finger portion of IDT1013.
- each IDT is provided with a narrow-pitch electrode finger in a portion where two IDTs are adjacent to each other, so that insertion loss in the passband is reduced. It is said that you can.
- Patent Document 1 Japanese Unexamined Patent Publication No. 2006-87145
- an elastic boundary wave filter device using a boundary acoustic wave propagating on a boundary between two media having different sound speeds has attracted attention.
- the electrode structure of the boundary acoustic wave device the electrode structure of the surface acoustic wave filter device can be appropriately used.
- the boundary acoustic wave filter device is formed using the same electrode structure as that of the longitudinally coupled resonator type surface acoustic wave filter device as described in Patent Document 1, the narrow pitch electrode finger portion is provided. Although the insertion loss in the passband can be reduced by this, an undesired large spurious may appear in the frequency range higher than the passband. Therefore, the boundary acoustic wave filter device having the above-described structure could not be used for an application in which spurious generation is not preferable at a higher frequency side than the passband.
- the object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to reduce insertion loss in the pass band by providing a narrow pitch electrode finger, so that the higher frequency side than the pass band can be reduced. It is an object of the present invention to provide a longitudinally coupled resonator type boundary acoustic wave filter device capable of effectively reducing unwanted spurious in the frequency range of the above.
- a boundary acoustic wave filter device includes a piezoelectric body, a dielectric layer laminated on the piezoelectric body, in front An elastic boundary wave filter device using an SH-type boundary acoustic wave propagating through the boundary between the piezoelectric body and the dielectric body, wherein the electrode structure comprises: 1 IDT and the 2nd and 3rd IDTs provided on both sides of the boundary acoustic wave propagation direction of the 1st IDT, which constitutes the longitudinally coupled resonator type boundary acoustic wave filter section
- the periodic force of some electrode fingers including the electrode finger arranged at the other IDT side end of one IDT S which is made smaller than the period of the electrode fingers in the part adjacent to the part, thereby providing a narrow pitch electrode finger part, and the narrow pitch electrode provided in
- a boundary acoustic wave filter device includes a piezoelectric body, a dielectric layer stacked on the piezoelectric body, and an electrode structure disposed at a boundary between the piezoelectric body and the dielectric body.
- the first and second longitudinally coupled resonator type filters each having the second and third IDTs are configured such that two IDTs are adjacent to each other in the first to third IDTs.
- the period of some electrode fingers including the electrode fingers arranged at the other IDT side end of one IDT is greater than the period of the electrode fingers of the part adjacent to the some electrode fingers.
- the first longitudinally coupled resonator type elastic boundary is formed so that a narrow pitch electrode finger portion is formed.
- the first and second longitudinal signals have a phase difference of 180 ° with respect to the input signal of the second longitudinally coupled resonator type boundary acoustic wave filter unit with respect to the phase of the output signal with respect to the input signal in the filter unit.
- the first to third IDT polarities of the coupled resonator type boundary acoustic wave filter section are defined, and the first and second longitudinally coupled resonances are provided with unbalanced terminals and first and second balanced terminals.
- the input end of the child-type boundary acoustic wave filter unit is connected to the unbalanced terminal, and the output ends of the first and second longitudinally coupled resonator type boundary acoustic wave filter units are the first and second balanced terminals, respectively.
- the electrode finger cycle is at least one of the first IDT narrow-pitch electrode finger portion and the second and third IDT narrow-pitch electrode finger portions. The remaining narrow pitch electrode finger portions are different from the cycle of the electrode finger portions.
- a third invention of the present application includes a piezoelectric body, a dielectric layer stacked on the piezoelectric body, and an electrode structure disposed at a boundary between the piezoelectric body and the dielectric body.
- SH boundary acoustic wave
- the period of some electrode fingers including the electrode fingers arranged at the other IDT side end of one IDT is made smaller than the period of the electrode fingers of the part adjacent to the part of the electrode fingers.
- a narrow pitch electrode finger is formed, and the input in the first longitudinally coupled resonator type boundary acoustic wave filter unit is input.
- the first and second longitudinally coupled resonator types so that the phase of the output signal with respect to the input signal of the second longitudinally coupled resonator type elastic boundary wave filter section is 180 ° different from the phase of the output signal with respect to the signal
- the first to third IDT polarities of the boundary acoustic wave filter section are defined, and have an unbalanced terminal and first and second balanced terminals, and the first and second longitudinally coupled resonator type elastic
- the input terminal of the boundary wave filter section is connected to the unbalanced terminal, and the output terminals of the first and second longitudinally coupled resonator type boundary acoustic wave filter sections are connected to the first and second balanced terminals, respectively.
- the second longitudinally coupled resonators are connected, and the period of the electrode fingers in the narrow pitch electrode finger portions of the first to third IDTs in the first longitudinally coupled resonator type filter unit is equalized.
- the electrode finger periods in the narrow pitch electrode finger portions of the first to third IDTs in the mold filter portion are equalized.
- the electrode finger period in the narrow pitch electrode finger part of the third IDT is different.
- the third and fifth longitudinal acoustic wave filter units designed in the same manner as the first longitudinally coupled resonator type boundary acoustic wave filter unit are provided.
- the input ends of the first to sixth longitudinally coupled resonator type boundary acoustic wave filters are not balanced.
- the output ends of the first, third, and fifth longitudinally coupled resonator type boundary acoustic wave filters are connected to the first balanced terminal, and the second, fourth, The output terminal of the sixth longitudinally coupled resonator boundary acoustic wave filter is connected to the second balanced terminal.
- the third longitudinally coupled resonator type boundary acoustic wave filter unit is connected in parallel to the first longitudinally coupled resonator type boundary acoustic wave filter unit, and the second longitudinally coupled resonance type boundary acoustic wave filter unit is connected.
- a wave filter device can be provided.
- the number of electrode fingers of the narrow pitch electrode finger portion of the first IDT and the narrowness of the second and third IDTs is different. In this case, the unnecessary spurious can be more effectively reduced by adjusting the number of electrode fingers of the IDT.
- the above-mentioned;! To third IDTs are provided and arranged on both sides of the boundary acoustic wave propagation direction in the region!
- the fourth and fifth IDTs are further provided, and thereby a 5IDT type longitudinally coupled resonator type elastic boundary wave filter unit is configured. Accordingly, it is possible to provide a boundary acoustic wave filter device that can further improve the power durability and that has a low loss.
- the insertion loss in the passband can be reduced.
- the periodic force of at least one narrow-pitch electrode finger portion is different from the cycle of the electrode fingers of the remaining narrow-pitch electrode finger portions. Since the effect of the two narrow pitch electrode fingers on the filter characteristics is different from the effect of the filter characteristics of the remaining narrow pitch electrode fingers, undesired spurious appearing on the high side of the passband should be reduced. Can do.
- the first to third IDTs are used. Since the narrow pitch electrode fingers are provided in the passband, the insertion loss in the passband can be reduced.
- the periodic force of at least one narrow-pitch electrode finger part of the first to third IDT narrow-pitch electrode finger parts is different from the period of the electrode fingers of the remaining narrow-pitch electrode finger parts. Also, it is possible to reduce unwanted spurious appearing on the high frequency side.
- the period of the electrode fingers of at least one narrow pitch electrode finger portion of the first to third IDT narrow pitch electrode finger portions is equal to that of the remaining narrow pitch electrode finger portions.
- the reason for the suppression of high frequency spurious due to the difference in the period is considered to be as follows.
- the cut angle of the piezoelectric material and the IDT normalized film thickness (IDT film thickness / IDT wavelength)
- the mechanical coupling coefficient is in a small range.
- the film thickness of the IDT is uniform, so even if a narrow-pitch electrode finger is provided, the film thickness of the narrow-pitch electrode finger is the same as the film thickness of the remaining part of the IDT. It is normal to be done.
- the normalized film thickness of the narrow-pitch electrode finger portion deviates from the range where the electromechanical coupling coefficient of the Stoneley wave becomes small in the direction in which the normalized film thickness increases. Therefore, the narrow pitch electrode fingers are excited and excited by a certain intensity of the Stonery wave, and the above-mentioned spurious appears in the frequency range higher than the passband.
- the period of the electrode fingers in at least one narrow pitch electrode finger part is different from the period of the electrode fingers in the remaining narrow pitch electrode finger parts. Therefore, the frequency band of the Stoneley wave excited and excited by at least one narrow pitch electrode finger and the Stoneley wave excited and excited by the remaining narrow pitch electrode fingers are shifted. It is considered that the spurious appearing on the band side is dispersed and the spurious is reduced accordingly.
- the first and second longitudinally coupled resonator-type filter sections have a balanced-unbalanced conversion function, and the first and second balanced terminals respectively.
- the first longitudinally coupled resonator type filter unit the period of the electrode fingers of the first to third IDT narrow pitch electrode finger units, and the second longitudinally coupled resonator type filter unit.
- FIG. 1 is a schematic plan view showing an electrode structure of a boundary acoustic wave filter device according to a first embodiment of the present invention.
- FIG. 2 is a schematic front sectional view of the boundary acoustic wave filter device according to the first embodiment of the present invention.
- FIG. 3 is a diagram showing the finoletor characteristics of a boundary acoustic wave filter device prepared as an embodiment and a comparative example.
- FIG. 4 is a schematic plan view showing an electrode structure of a boundary acoustic wave filter device according to a second embodiment of the present invention.
- FIG. 5 is a schematic plan view showing an electrode structure of a boundary acoustic wave filter device according to a third embodiment of the present invention.
- FIG. 6 is a schematic plan view showing an electrode structure of a boundary acoustic wave filter device according to a modification.
- FIG. 7 is a schematic plan view showing an electrode structure of a conventional longitudinally coupled resonator type surface acoustic wave filter device.
- FIG. 1 is a schematic plan view showing an electrode structure of a longitudinally coupled resonator type boundary acoustic wave filter device according to a first embodiment of the present invention
- FIG. 2 shows the boundary acoustic wave filter device.
- the boundary acoustic wave filter device 100 includes a piezoelectric substrate 101 that also has a LiNbO force with a main surface obtained by rotating the Y axis by 15 ° ⁇ 10 °. Dielectric 1 on piezoelectric substrate 101
- the dielectric 102 is made of oxide silicon.
- silicon oxide SiO or the like can be suitably used.
- dielectric 102 is oxidized
- It is composed of other dielectric materials such as nitride nitride other than key! /.
- An electrode structure 103 is formed at the boundary between the piezoelectric substrate 101 and the dielectric 102. This electrode structure 103 is schematically shown in FIG.
- the dielectric 102 is provided with a plurality of openings 102a, 102b force S.
- a part of the electrode structure 103 is exposed in the openings 102a and 102b.
- the conductive patterns 104a and 104b force S are provided in the openings 102a and 102b.
- the conductive patterns 104a and 104b are electrically connected to the electrode structure exposed in the opening and reach the upper surface of the dielectric body 102 outside the opening.
- the conductive patterns 104a and 104b are electrically connected to the external electrodes 105a and 105b.
- the external electrodes 105a and 105b correspond to an unbalanced terminal, a balanced terminal, or a terminal connected to the ground potential, which will be described later.
- the boundary acoustic wave filter device 100 is a longitudinally coupled resonator type boundary acoustic wave filter device using an SH type boundary acoustic wave that propagates the boundary between the piezoelectric substrate 101 and the dielectric 102.
- the boundary acoustic wave filter device 100 is a longitudinally coupled resonator type filter device using an SH type boundary acoustic wave.
- the GSM1900MHz band reception filter has a passband of 1930MHz to 1990MHz. Used! /.
- the illustrated electrode structure is provided between the unbalanced terminal 106 and the first and second balanced terminals 107 and 108. Yes.
- the first longitudinally coupled resonator type boundary acoustic wave filter unit 110 is connected to the unbalanced terminal 106 via a one-port type boundary acoustic wave resonator 130.
- the first longitudinally coupled resonator type ⁇ The boundary acoustic wave filter unit 110 is connected to the first balanced terminal 107 via a 1-port boundary acoustic wave resonator 150.
- Each of the 1-port inertial boundary wave resonators 130 and 150 includes an IDT and reflectors disposed on both sides of the IDT in the inertial boundary wave propagation direction.
- the first longitudinally coupled resonator type boundary acoustic wave filter unit 110 includes a first IDT 113 disposed in the center and second and second IDTs 113 disposed on both sides of the first IDT 113 in the boundary acoustic wave propagation direction.
- the longitudinally coupled resonator type boundary acoustic wave filter unit 110 is a 3IDT type longitudinally coupled resonator type filter as described above. Then, the IDTs 112 and 113 can be divided into the parts where the first and second IDTs 112 and 113 are adjacent to each other and the first and third IDTs 113 and 114 are adjacent to each other. Narrow pitch electrode fingers are provided! /, Respectively.
- the electrode finger pitch of the portion where the plurality of electrode fingers 112a on the first IDT 113 side end of the second IDT 112 is the narrow pitch electrode finger portion 112A having a relatively short cycle of electrode fingers.
- the period of the electrode fingers of the narrow pitch electrode finger portion 112A is shorter than the electrode finger pitch of the remaining portion of the IDT 112 adjacent to the narrow pitch electrode finger portion 112A.
- a narrow pitch electrode finger portion 113A is provided at an end portion on the second IDT 112 side.
- the narrow pitch electrode finger portion 113A has a plurality of electrode fingers 113a, and the cycle of the electrode fingers is relatively shorter than the electrode finger pitch of the IDT 113 adjacent to the narrow pitch electrode finger portion 113A.
- a narrow pitch electrode finger 113B is also provided on the third IDT 114 side.
- the IDTs 112 to 114 are formed with narrow pitch electrode caps 112A, 113A, 113B, and 114A.
- the pitch force of the electrode fingers of the narrow pitch electrode fingers 112A, 113A, 113B, 114A of the first longitudinally coupled resonator type boundary acoustic wave filter unit 110 This is made smaller than the electrode finger pitch of the narrow pitch electrode finger portions 122A, 123A, 123B, and 124A of the sexual boundary wave filter portion 120 !.
- a second longitudinally coupled resonator type boundary acoustic wave filter unit 120 is also connected to the unbalanced terminal 106 via a one-port inertial boundary acoustic wave resonator 140.
- the second longitudinally coupled resonator type boundary acoustic wave filter unit 120 is connected to the second balanced terminal 108 via a one-port type boundary acoustic wave resonator 160.
- the 1-port inertial boundary wave resonators 140 and 160 are configured in the same manner as the 1-port inertial boundary wave resonators 130 and 150.
- the second longitudinally coupled resonator-type boundary acoustic wave filter unit 120 includes a first IDT 123 disposed in the center and second and second IDTs disposed on both sides of the first IDT 123 in the boundary acoustic wave propagation direction.
- Third IDTs 122 and 124 and reflectors 121 and 125 are provided.
- the second longitudinally coupled resonator-type boundary acoustic wave filter unit 120 has a central first IDT 123 whose polarity is the same as that of the first IDT 113 of the first longitudinally coupled resonator-type boundary acoustic wave filter unit 110.
- the structure is the same except that the polarity is reversed. That is, in the second longitudinally coupled resonator-type boundary acoustic wave filter unit 120, the portion where the first and second IDTs 123 and 122 are adjacent to each other and the portion where the first and third IDTs 123 and 124 are adjacent to each other In FIG. 2, narrow pitch electrode swords 122A, 123A, 123B, and 124A are formed on IDTs 12 to 124, respectively.
- the pitch of the electrode fingers of the first and third IDT narrow pitch electrode finger portions 122A and 124A is the same as that of the first IDT 123 narrow pitch electrode finger.
- the pitch is shorter than the pitch of the electrode fingers of the portions 123A and 123B.
- the electromechanical coupling coefficient can be set to an appropriate value by changing the propagation direction of these boundary acoustic waves.
- boundary acoustic wave resonator it is not always necessary to make the boundary wave propagation directions of the longitudinally coupled resonator type boundary acoustic wave filter section and the boundary acoustic wave resonator different from each other, and the boundary acoustic wave resonator is not necessarily required. 130, 140, 150, 160 are not necessarily provided.
- the narrow pitch electrode finger sections 112A, 113A, 113B, 114A, 122A, 123A, 123B and 124A are provided. The continuity of the IDTs adjacent to each other is enhanced, and the force S reduces the insertion loss in the passband.
- the electrode finger pitch force at the narrow pitch electrode finger portions 112A, 113A, 113B, 114A of the first longitudinally coupled resonator type boundary acoustic wave filter portion 110 is The pitch of the electrode fingers in the narrow pitch electrode finger portions 122A, 123A, 123B, and 124A of the longitudinally coupled resonator type boundary acoustic wave filter portion 120 is made smaller. As a result, it is possible to effectively reduce unnecessary spurious in the frequency range higher than the pass band. This will be described with reference to FIG.
- FIG. 3 shows the filter characteristics of the longitudinally coupled resonator type boundary acoustic wave filter device of the above embodiment and the filter characteristics of a boundary acoustic wave filter device of a comparative example prepared for comparison.
- the period of the IDT electrode fingers other than the narrow pitch electrode fingers is set to 1. 675 111, and the narrow pitch of the first longitudinally coupled resonator type boundary acoustic wave filter 1 10 is set.
- the period of the electrode fingers of the electrode fingers 112A, 113A, 113B, 114A is 1 ⁇ 46634 11 m, and the narrow pitch electrode fingers 122A, 123A, 123B, 124A of the second longitudinally coupled resonator type boundary acoustic wave filter unit 120
- the electrode finger cycle was 1.48634 ⁇ .
- the boundary acoustic wave filter device of the comparative example prepared for comparison all electrode finger pitches of the narrow pitch electrode finger portions are 1. 47634 111, and the period of the electrode fingers of the remaining main electrode portions is 1.
- a boundary acoustic wave filter device was fabricated in the same manner as in the above example except that the length was 675 m.
- the number of electrode fingers of the narrow pitch electrode finger portions 112A, 113A, 113B, 114A, 122A, 123A, 123B, and 124A is three.
- the solid line in FIG. 3 shows the result of the embodiment, and the broken line shows the result of the comparative example.
- the PCS reception band which is the passband, from 1930;
- large spurs appeared near 2190 MHz, which is on the high frequency side.
- the spurious near 2190 MHz is very small, and the spurious is improved by about 3 dB.
- the attenuation near 2190 MHz is improved from 28.4 dB to 31.5 dB according to the embodiment.
- the reason why the spurious near 2190 MHz, that is, on the higher frequency side than the passband is considered to be as follows.
- the spurious is an unnecessary mode due to a single Stone wave that becomes spurious with respect to the SH type boundary acoustic wave.
- the IDT film thickness is normally set to a film thickness with a small electromechanical coupling coefficient of the Stoneley wave.
- the normalized film thickness depends on the period of the electrode finger, the narrow pitch electrode finger part is excited and received at a certain intensity, and the spurious as described above must appear. There wasn't.
- the pass band on the transmission side such as a PCS reception band filter.
- N / A it is possible to provide a filter device suitable for applications in which this is strongly required.
- the period of the electrode fingers of the narrow pitch electrode finger portion of the first longitudinally coupled resonator type boundary acoustic wave filter unit 110 is set as the second longitudinally coupled resonator type boundary acoustic wave filter unit. However, the period is smaller than the period of the electrode fingers of the narrow pitch electrode fingers of the second longitudinally coupled resonator type boundary acoustic wave filter section. It's okay.
- the period of the narrow pitch electrode finger portion of the first longitudinally coupled resonator type boundary acoustic wave filter unit and the second longitudinally coupled resonator type boundary acoustic wave filter unit are the first longitudinally coupled resonator type boundary acoustic wave filter unit.
- Narrow-pitch electrode The force that caused the period of the electrode fingers to be different in the first longitudinally coupled resonator-type boundary acoustic wave filter unit 110, the period of the electrode fingers of at least one narrow-pitch electrode finger part In the second longitudinally coupled resonator type boundary acoustic wave filter unit, which may be different from the period of the electrode fingers of the narrow pitch electrode finger part, the period of the electrode fingers of the at least one narrow pitch electrode finger part remains. It may be different from the period of the narrow pitch electrode finger portion.
- the present invention is characterized in that the spurious appearing in the filter characteristics is dispersed by the narrow pitch electrode fingers, thereby reducing the size of the spurious on the high passband side. . Therefore, in one longitudinally coupled resonator type boundary acoustic wave filter, for example, the period of the electrode finger of the narrow pitch electrode finger part of the first IDT 113 is set to the period of the electrode finger of the narrow pitch electrode finger part of the second IDT 113. It may be larger or smaller than the period. In the above-described embodiment in which the first and second longitudinally coupled resonator type boundary acoustic wave filter units are provided, at least one of the first and second longitudinally coupled resonator type boundary acoustic wave filter units is provided. As described above, by making the period of the electrode fingers of at least one narrow pitch electrode finger part different from the period of the electrode fingers of the remaining narrow pitch electrode finger parts, the spurious on the high frequency side is dispersed. Spurious can be reduced.
- the spurious can be dispersed further by changing the number of electrode fingers as well as changing the period of the electrode fingers of the narrow pitch electrode finger portion. It becomes possible to reduce the spurious. Therefore, in a modification in which the period of the electrode fingers of at least one narrow pitch electrode finger part is different from the period of the remaining narrow pitch electrode finger parts, preferably, for example, the electrode of the narrow pitch electrode finger part of the first IDT The number of fingers and the second and third IDT.
- the number of electrode fingers of the narrow pitch electrode finger portion of the first IDT is the number of electrode fingers of the narrow pitch electrode finger portion of the first IDT
- the number of electrode fingers of the IDT narrow pitch electrode finger of 3 is equalized! /, May! /.
- FIG. 4 is a schematic plan view showing an electrode structure of the boundary acoustic wave filter device according to the second embodiment of the present invention.
- the first and second longitudinally coupled resonators Forces with 1-port boundary acoustic wave resonators connected to the front and rear stages of the boundary acoustic wave filter units 110 and 120 in the boundary acoustic wave filter device 200 shown in FIG.
- the longitudinally coupled resonator type boundary acoustic wave filter units 110 and 120 are directly connected.
- the third and fourth longitudinally coupled resonator type boundary acoustic wave filter units 210 and 220 are connected to the subsequent stage of the first and second longitudinally coupled resonator type boundary acoustic wave filter units 110 and 120, respectively. Yes.
- the longitudinally coupled resonator type boundary acoustic wave filter units 210 and 220 are 3IDT type longitudinally coupled resonator type boundary acoustic wave filter units, similarly to the longitudinally coupled resonator type boundary acoustic wave filter units 110 and 120.
- the longitudinally coupled resonator type boundary acoustic wave filter units 210 and 220 are configured in substantially the same manner as the first longitudinally coupled resonator type boundary acoustic wave filter unit 110. That is, IDTs 212 to 214 to be described later in the longitudinally coupled resonator type boundary acoustic wave filter unit 210, IDTs 222 to 224 to be described later in the longitudinally coupled resonator type boundary acoustic wave filter unit 220, and the first longitudinally coupled resonator type boundary acoustic wave boundary The IDTs 112 to 114 in the wave filter unit 110 and the corresponding IDTs have the same polarity.
- one ends of the second and third IDTs 112 and 114 of the first longitudinally coupled resonator type boundary acoustic wave filter unit 110 are connected to the second longitudinally coupled resonator type boundary acoustic wave filter unit 210 of the third longitudinally coupled resonator type boundary acoustic wave filter unit 210, respectively.
- the other ends of IDTs 212 and 214 are connected to ground potential.
- One end of the center first IDT 213 is connected to the ground potential, and the other end is connected to the first balanced terminal 107.
- one end force S of the second and third IDTs 222 and 224 of the fourth longitudinally coupled resonator type boundary acoustic wave filter unit 220, and the second longitudinally coupled resonator type boundary acoustic wave filter unit 120 of the second longitudinally coupled resonator type boundary acoustic wave filter unit 120 It is connected to the 2nd and 3rd IDTs 122 and 124, and the other end is connected to the ground potential.
- One end of the first IDT 223 is connected to the ground potential, and the other end is connected to the second balanced terminal 108.
- the IDTs are adjacent to each other in the third and fourth longitudinally coupled resonator type boundary acoustic wave filter units 210 and 220 as well.
- Narrow pitch electrode finger portions 212A, 213A, 213B, 214A, 222A, 223A, 223B, and 224A are provided in the portion. Then, the pitch of electrode fingers in the narrow pitch electrode fingers 213A, 213B, 212A, 214A, and the electrode fingers of the narrow pitch electrode fingers 223A, 223B, 222A, 224A It is different from the cycle.
- the period of the electrode fingers of the narrow-pitch electrode finger portions is dispersed, so that it is higher than the passband. It is possible to suppress spurious in it.
- FIG. 5 is a schematic plan view showing an electrode structure of a boundary acoustic wave filter device according to the third embodiment of the present invention.
- the longitudinally coupled resonator type boundary acoustic wave filter unit 310 includes the first IDT 314 disposed in the center of the boundary acoustic wave propagation direction.
- the IDT 314 has first and second divided IDT sections 314a and 314b that are provided by being divided in the boundary wave propagation direction by dividing one bus bar.
- the second and third IDTs 313 and 315 are arranged on both sides of the IDT 314 in the boundary wave propagation direction, and the fourth and fifth IDTs 312 and 316 are arranged on both sides of the boundary wave propagation direction in the region where the IDTs 313 to 315 are provided. Is arranged. Reflectors 311 and 317 are disposed on both sides of the boundary wave propagation direction of the region where IDTs 312 to 316 are disposed.
- a 1-port boundary acoustic wave resonator 320 is connected between the unbalanced terminal 106 and the ground potential.
- each of the second and third IDTs 313 and 315 of the longitudinally coupled resonator-type boundary acoustic wave filter unit 310 is commonly connected and electrically connected to the unbalanced terminal 106.
- the other ends of the ID T313 and 315 are connected to the ground potential.
- one end of the fourth IDT 312 and the divided IDT portion 314 a are connected in common and connected to the first balanced terminal 107 via the 1-port boundary acoustic wave resonator 330.
- the other end of IDT312 is connected to ground potential.
- the second divided IDT unit 314b and one end of the fifth IDT 316 are connected in common and electrically connected to the second balanced terminal 108 via the 1-port inertial boundary wave resonator 340. ing.
- the other end of IDT316 is connected to ground potential.
- the common bus bar side of the IDT 314 is connected to the ground potential.
- the narrow pitch electrode finger portions 3 12A, 313A, 313B, 314A, 314B, 315A, 315B, 316A are provided.
- the period of the electrode fingers of the narrow pitch electrode fingers 314A and 314B of the first IDT 314 and the narrow pitch electrode finger portions 313B and 315A of the IDT 314 side ends of the second and third IDTs 313 and 315
- the electrode finger cycle is different. Therefore, the spurious generated by the presence of the narrow pitch electrode fingers is dispersed, and the size of the spurious on the high passband side can be reduced.
- the period of the electrode fingers of the narrow pitch electrode finger portions 312A and 316A of the fourth and fifth IDTs 312 and 316 is different from the cycle of the electrode fingers of the narrow pitch electrode finger portions 313A and 315B. That is, in the portion where IDTs are adjacent to each other, the periods of the electrode fingers of the narrow pitch electrode finger portions on both sides are different. As described above, by changing the period of the electrode fingers of the narrow pitch electrode fingers on both sides between adjacent IDTs in all the parts where the IDTs are adjacent to each other, the spurious on the high passband side is reduced. It is possible to disperse more effectively, thereby making it possible to reduce spuriousness more effectively.
- the polarity of IDT 315 is inverted with respect to the polarity of IDT 313 in order to realize a balanced-unbalanced conversion function.
- the polarity of multiple IDTs for realizing the balanced-unbalanced conversion function in the 5IDT type longitudinally coupled resonator type inertial boundary wave filter is appropriately changed as long as the balanced-unbalanced conversion function can be realized. be able to.
- a 5IDT type longitudinally coupled resonator type boundary acoustic wave filter is provided between the unbalanced terminal 106 and the first and second balanced terminals 107 and 108. 410 is arranged.
- the longitudinally coupled resonator type boundary acoustic wave filter unit 410 includes the first IDT 414 disposed at the center and the second IDTs 413, 415 disposed on both sides of the boundary wave propagation direction of the first IDT 414. And fourth and fifth IDTs 412 and 416 and reflectors 411 and 417 disposed on both sides of the boundary wave propagation direction of the region where IDTs 413 to 415 are provided.
- one end of the first IDT 414 and one end of each of the fourth and fifth IDTs 412, 416 are connected in common and connected to the unbalanced terminal 106 via the 1-port boundary acoustic wave resonator 420. It has been done.
- the other ends of the IDTs 412, 414, and 416 are connected to the ground potential.
- the second ID The polarity of the third IDT 415 is inverted with respect to the polarity of T413.
- One end of each of the IDTs 413 and 415 is connected to the ground potential, the other end of the IDT 413 is connected to the first balanced terminal 107, and the other end of the third IDT 415 is connected to the second balanced terminal 108.
- a 1-port boundary acoustic wave resonator 430 is connected between the first and second balanced terminals 107 and 108.
- the polarity of IDT 415 is inverted with respect to the polarity of IDT 413, so that a balanced-unbalanced conversion function is realized.
- narrow pitch electrode finger portions are provided in the IDTs on both sides in the portion where the IDTs are adjacent to each other, and the period of the electrode fingers of the narrow pitch electrode finger portions on both sides is It is different.
- the first IDT 414 has narrow pitch electrode fingers 414A and 414B on both sides.
- the period of the electrode finger of the narrow pitch electrode finger 413B provided at the end of the IDT 413 on the IDT 414 side, and the narrow pitch electrode finger portion 414A of the IDT 414 The period of the electrode finger is different.
- the cycle of electrode fingers is also different between the narrow pitch electrode finger portion 412A provided in the IDT 412 and the narrow pitch electrode finger portion 413A of the IDT 413.
- the narrow pitch electrode finger portions 412A and 413A are adjacent to each other
- the narrow pitch electrode finger portions 413B and the narrow pitch electrode finger portions 414A are adjacent to each other
- the narrow pitch electrode finger portions 414B and the narrow pitch electrode finger portions 414B are narrow.
- Pitch electrode fingers 41 5A are adjacent to each other
- narrow pitch electrode fingers 415B and narrow pitch electrode fingers 416A are adjacent to each other!
- the pitch of the electrode fingers of the narrow-pitch electrode fingers is made different so that the spurious is dispersed and the spurious can be reduced.
- the piezoelectric body may use LiNbO having a force composed of LiNbO whose main surface is a surface obtained by rotating the Y axis by 15 ° ⁇ 10 °.
- piezoelectric materials such as LiTaO or quartz to form the piezoelectric body! /.
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112007002105T DE112007002105T5 (de) | 2006-09-25 | 2007-09-05 | Grenzakustikwellenfilter |
JP2008536317A JPWO2008038502A1 (ja) | 2006-09-25 | 2007-09-05 | 弾性境界波フィルタ装置 |
US12/398,237 US8525621B2 (en) | 2006-09-25 | 2009-03-05 | Boundary acoustic wave filter |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2006-259281 | 2006-09-25 | ||
JP2006259281 | 2006-09-25 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/398,237 Continuation US8525621B2 (en) | 2006-09-25 | 2009-03-05 | Boundary acoustic wave filter |
Publications (1)
Publication Number | Publication Date |
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WO2008038502A1 true WO2008038502A1 (fr) | 2008-04-03 |
Family
ID=39229941
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2007/067322 WO2008038502A1 (fr) | 2006-09-25 | 2007-09-05 | Filtre d'onde acoustique d'interface |
Country Status (4)
Country | Link |
---|---|
US (1) | US8525621B2 (ja) |
JP (1) | JPWO2008038502A1 (ja) |
DE (1) | DE112007002105T5 (ja) |
WO (1) | WO2008038502A1 (ja) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009260463A (ja) * | 2008-04-14 | 2009-11-05 | Murata Mfg Co Ltd | 弾性波フィルタ装置 |
WO2010035372A1 (ja) * | 2008-09-24 | 2010-04-01 | 株式会社村田製作所 | 弾性波フィルタ装置 |
WO2010125934A1 (ja) * | 2009-04-30 | 2010-11-04 | 株式会社村田製作所 | 弾性波装置 |
JP2018050158A (ja) * | 2016-09-21 | 2018-03-29 | 太陽誘電株式会社 | 弾性波デバイス |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010251964A (ja) * | 2009-04-14 | 2010-11-04 | Murata Mfg Co Ltd | 弾性波フィルタ及び通信機 |
DE102010005306B4 (de) | 2010-01-21 | 2015-06-18 | Epcos Ag | DMS Filter mit verbesserter Signalunterdrückung |
Citations (2)
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JP2002084163A (ja) * | 2000-05-22 | 2002-03-22 | Murata Mfg Co Ltd | 縦結合共振子型弾性表面波フィルタ |
WO2006087875A1 (ja) * | 2005-02-16 | 2006-08-24 | Murata Manufacturing Co., Ltd. | バランス型弾性波フィルタ装置 |
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JP3391346B2 (ja) * | 2000-04-18 | 2003-03-31 | 株式会社村田製作所 | 縦結合共振子型弾性表面波フィルタ |
JP4285472B2 (ja) | 2000-04-18 | 2009-06-24 | 株式会社村田製作所 | 縦結合共振子型弾性表面波フィルタ |
EP1276235A1 (en) * | 2001-07-13 | 2003-01-15 | Matsushita Electric Industrial Co., Ltd. | Surface acoustic wave filter and communication device using the filter |
JP3826816B2 (ja) * | 2001-08-29 | 2006-09-27 | 株式会社村田製作所 | 弾性表面波装置 |
US7453184B2 (en) * | 2003-04-18 | 2008-11-18 | Murata Manufacturing Co., Ltd. | Boundary acoustic wave device |
WO2006068087A1 (ja) * | 2004-12-20 | 2006-06-29 | Murata Manufacturing Co., Ltd. | バランス型弾性波フィルタ装置 |
JP4438799B2 (ja) * | 2004-12-24 | 2010-03-24 | 株式会社村田製作所 | バランス型sawフィルタ |
JP2006254410A (ja) | 2005-02-10 | 2006-09-21 | Murata Mfg Co Ltd | バランス型弾性波フィルタ |
-
2007
- 2007-09-05 JP JP2008536317A patent/JPWO2008038502A1/ja active Pending
- 2007-09-05 WO PCT/JP2007/067322 patent/WO2008038502A1/ja active Application Filing
- 2007-09-05 DE DE112007002105T patent/DE112007002105T5/de not_active Withdrawn
-
2009
- 2009-03-05 US US12/398,237 patent/US8525621B2/en active Active
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2002084163A (ja) * | 2000-05-22 | 2002-03-22 | Murata Mfg Co Ltd | 縦結合共振子型弾性表面波フィルタ |
WO2006087875A1 (ja) * | 2005-02-16 | 2006-08-24 | Murata Manufacturing Co., Ltd. | バランス型弾性波フィルタ装置 |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009260463A (ja) * | 2008-04-14 | 2009-11-05 | Murata Mfg Co Ltd | 弾性波フィルタ装置 |
WO2010035372A1 (ja) * | 2008-09-24 | 2010-04-01 | 株式会社村田製作所 | 弾性波フィルタ装置 |
CN102160287A (zh) * | 2008-09-24 | 2011-08-17 | 株式会社村田制作所 | 弹性波滤波器装置 |
US8736402B2 (en) | 2008-09-24 | 2014-05-27 | Murata Manufacturing Co., Ltd. | Elastic wave filter device with IDT electrodes that include a narrower-pitch portion |
WO2010125934A1 (ja) * | 2009-04-30 | 2010-11-04 | 株式会社村田製作所 | 弾性波装置 |
JP2018050158A (ja) * | 2016-09-21 | 2018-03-29 | 太陽誘電株式会社 | 弾性波デバイス |
US10763818B2 (en) | 2016-09-21 | 2020-09-01 | Taiyo Yuden Co., Ltd. | Acoustic wave device |
Also Published As
Publication number | Publication date |
---|---|
US8525621B2 (en) | 2013-09-03 |
JPWO2008038502A1 (ja) | 2010-01-28 |
US20090160574A1 (en) | 2009-06-25 |
DE112007002105T5 (de) | 2009-10-01 |
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