WO2023149471A1 - Filtre à ondes acoustiques et dispositif de communication - Google Patents

Filtre à ondes acoustiques et dispositif de communication Download PDF

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WO2023149471A1
WO2023149471A1 PCT/JP2023/003202 JP2023003202W WO2023149471A1 WO 2023149471 A1 WO2023149471 A1 WO 2023149471A1 JP 2023003202 W JP2023003202 W JP 2023003202W WO 2023149471 A1 WO2023149471 A1 WO 2023149471A1
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parallel
parallel resonator
wave filter
resonator
pitch
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PCT/JP2023/003202
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English (en)
Japanese (ja)
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宏行 田中
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京セラ株式会社
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    • 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/64—Filters using surface acoustic waves

Definitions

  • One aspect of the present disclosure relates to an elastic wave filter.
  • Patent Document 1 discloses a ladder-type filter having a plurality of series resonators and a plurality of parallel resonators as an example of an acoustic wave filter.
  • An acoustic wave filter includes a plurality of series resonators, a first parallel resonator having a first resonance ripple, and a plurality of parallel resonators including other parallel resonators.
  • the first resonance ripple is located between a main resonance frequency and an anti-resonance frequency of the first parallel resonator, and the main resonance frequency of the first parallel resonator is set among the other parallel resonators, higher than the main resonant frequency of the at least one parallel resonator;
  • FIG. 3 is a diagram showing the configuration of the main part of the acoustic wave filter of Embodiment 1; FIG. It is a figure which shows the structure of the principal part of the elastic wave filter as a comparative example.
  • FIG. 3 is a diagram showing attenuation characteristics of the elastic wave filter of Embodiment 1 and the elastic wave filter of the comparative example;
  • FIG. 4 is a diagram showing respective frequency characteristics of a first parallel resonator and a normal parallel resonator;
  • FIG. 3 is a plan view showing one configuration example of a resonator;
  • FIG. 6 is a cross-sectional view taken along line Ic-Ic of FIG. 5; 6 is an enlarged plan view of a part of the IDT electrode in FIG. 5;
  • FIG. 6 is an enlarged plan view of a part of the reflector in FIG. 5;
  • FIG. FIG. 10 is a diagram showing the configuration of the main part of the acoustic wave filter of Embodiment 2;
  • FIG. 5 is a diagram showing attenuation characteristics of the elastic wave filter of Embodiment 2 and the elastic wave filter of Embodiment 1;
  • FIG. 5 is a diagram showing frequency characteristics of a second parallel resonator and a first parallel resonator;
  • FIG. 10 is a diagram illustrating a schematic configuration of a communication device according to Embodiment 3;
  • Embodiment 1 The acoustic wave filter 100A of Embodiment 1 will be described below.
  • members having the same functions as the members explained in the first embodiment are denoted by the same reference numerals in the subsequent embodiments, and the explanation thereof will not be repeated.
  • descriptions of well-known technical matters are also omitted as appropriate.
  • Each configuration and each numerical value described in this specification are merely examples unless otherwise specified. Therefore, unless otherwise specified, the positional relationship of each member is not limited to the examples in each figure. Also, each member is not necessarily illustrated to scale.
  • FIG. 1 is a diagram showing the configuration of a main part of an elastic wave filter 100A.
  • the acoustic wave filter 100A has multiple (eg, five) series resonators 1S and multiple (eg, four) parallel resonators 1P.
  • the acoustic wave filter 100A may be, for example, a ladder filter.
  • the series resonator 1S and the parallel resonator 1P are collectively referred to as the resonator 1.
  • FIG. A configuration example of the resonator 1 as an elastic wave device will be described later.
  • each of the five series resonators 1S is distinguished, they are denoted as series resonators 1S-1 to 1S-5, respectively. Further, when distinguishing between the four parallel resonators 1P, they are denoted as parallel resonators 1P-1 to 1P-5, respectively.
  • the elastic wave filter 100A includes a first parallel resonator 1PA having a first resonance ripple and other parallel resonators as the plurality of parallel resonators 1P. As will be described later, the first parallel resonator 1PA has frequency characteristics different from those of the other parallel resonators.
  • the first parallel resonator 1PA in the example of FIG. 1 is the parallel resonator 1P-2.
  • the other three parallel resonators excluding the first parallel resonator 1PA that is, the parallel resonators 1P-1, 1P-3, and 1P-4 are equivalent to each other. It has frequency characteristics. For this reason, in the first embodiment, parallel resonators 1P-1, 1P-3, and 1P-4 are also generically referred to as normal parallel resonator 1PN.
  • the elastic wave filter 100A includes an input terminal Tin, an output terminal Tout, a series wiring SL connecting a plurality of series resonators 1S, and a plurality of parallel resonators 1P connecting each of the parallel resonators 1P. and parallel wiring PL.
  • the input terminal Tin is simply abbreviated as Tin as appropriate.
  • the acoustic wave filter 100A may have a plurality of ground terminals TGND respectively corresponding to the plurality of PLs.
  • the acoustic wave filter 100A has four PLs and TGNDs, respectively. When distinguishing between the four PLs, they are denoted as PL-1 to PL-4. Moreover, when distinguishing between the four TGNDs, they are denoted as TGND-1 to TGND-4.
  • the elastic wave filter 100A may be configured as a filter that filters an electrical signal input to Tin and outputs the filtered electrical signal to Tout.
  • SL may be connected to Tin and Tout. Therefore, the series resonators 1S-1 to 1S-5 may be connected to Tin and Tout through SL, respectively.
  • series resonator 1S-1 is the closest series resonator to Tin.
  • the series resonator 1S-5 is the series resonator closest to Tout (in other words, farthest from Tin).
  • PL-1 is branched from SL between series resonators 1S-1 and 1S-2 and is connected to TGND-1.
  • PL-2 branches from SL between series resonators 1S-2 and 1S-3 and is connected to TGND-2.
  • PL-3 branches from SL between series resonators 1S-3 and 1S-4 and is connected to TGND-3.
  • PL-4 branches from SL between series resonators 1S-4 and 1S-5 and is connected to TGND-4.
  • parallel resonators 1P-1 to 1P-4 may be connected to TGND-1 to TGND-4 via PL-1 to PL-4, respectively. According to this configuration, the electrical signal can be filtered by releasing unnecessary components contained in the electrical signal to TGND via the parallel resonator 1P.
  • parallel resonator 1P-1 is the parallel resonator closest to Tin.
  • the parallel resonator 1P-4 is the series resonator closest to Tout.
  • FIG. 2 is a diagram showing the configuration of the main part of the elastic wave filter 100R.
  • the acoustic wave filter 100R normally includes only parallel resonators 1PN as the plurality of parallel resonators 1P. That is, in the elastic wave filter 100R, unlike the elastic wave filter 100A, the parallel resonator 1P-2 is the normal parallel resonator 1PN.
  • FIG. 3 illustrates attenuation characteristics of each of the elastic wave filters 100A and 100R.
  • the horizontal axis indicates frequency (unit: MHz), and the vertical axis indicates attenuation (unit: dB).
  • the solid line indicates the characteristics of the elastic wave filter 100A (first embodiment), and the dotted line indicates the characteristics of the elastic wave filter 100R (comparative example).
  • the amount of attenuation can also be rephrased as the amount of transmission. Therefore, attenuation characteristics can also be called transmission characteristics.
  • the elastic wave filter 100A includes the first parallel resonator 1PA as the parallel resonator 1P. Therefore, as shown in FIG. 3, in the elastic wave filter 100A, unlike the elastic wave filter 100R, the first resonance ripple caused by the first parallel resonator 1PA occurs.
  • the first resonance ripple is located between the main resonance frequency f1a and the anti-resonance frequency f1b of the first parallel resonator 1PA. Examples of f1a and f1b are described below with reference to FIG. Furthermore, f1a is higher than the main resonance frequency of at least one parallel resonator among the other parallel resonators. Therefore, the first parallel resonator 1PA may be configured to satisfy these conditions.
  • the steepness of the attenuation characteristic in the transition band located between the transmission band and the cutoff band of the elastic wave filter compared to the elastic wave filter 100R due to the first resonance ripple. is improved.
  • the acoustic wave filter 100A by setting f1a as described above, it is possible to reduce the possibility that the first resonance ripple will have a raised portion in the transition region on the low frequency side. Therefore, according to the elastic wave filter 100A, the steepness of the attenuation characteristic in the transition region on the low frequency side can be improved compared to the elastic wave filter 100R.
  • the steepness of the attenuation characteristic of the elastic wave filter can be improved by a method different from the conventional one.
  • f1a may be higher than the main resonance frequency of all parallel resonators among the other parallel resonators. In this case, the steepness of the attenuation characteristic in the transition region on the low frequency side can be further improved. Therefore, in the example of Embodiment 1, f1a may be higher than the main resonance frequency of the normal parallel resonator 1PN.
  • FIG. 4 illustrates frequency characteristics of each of the first parallel resonator 1PA and the normal parallel resonator 1PN.
  • the solid line indicates the characteristics of the first parallel resonator 1PA
  • the dotted line indicates the characteristics of the normal parallel resonator 1PN.
  • the graph denoted by reference numeral 4000A shows impedance characteristics of each of the first parallel resonator 1PA and the normal parallel resonator 1PN.
  • the frequencies are shifted so as to match the position of the main resonance frequency (0° phase).
  • the horizontal axis indicates frequency (unit: MHz), and the vertical axis indicates the absolute value (magnitude) of impedance (unit: Ohm).
  • a graph denoted by reference numeral 4000B shows phase characteristics of impedance of each of the first parallel resonator 1PA and the normal parallel resonator 1PN.
  • the horizontal axis indicates frequency (unit: MHz)
  • the vertical axis indicates impedance phase (unit: degree).
  • phase of impedance is simply abbreviated as "phase”.
  • f1b (anti-resonance frequency of the first parallel resonator 1PA) is the frequency at which the absolute value of the impedance of the first parallel resonator 1PA takes the maximum value.
  • the frequency f1r of the first resonance ripple is the frequency at which the phase takes a minimum value in the transmission band of the acoustic wave filter 100A.
  • f1r 1964.0 MHz.
  • the first resonance ripple is located between f1a and f1b.
  • the first resonance ripple is located between f1a and f1b.
  • f1r is located between f1a and f1b.
  • the phase (impedance phase) of the first parallel resonator 1PA may be 50° or less.
  • the steepness of the attenuation characteristic in the transition region on the low frequency side can be further improved in the acoustic wave filter 100A.
  • the phase of the first parallel resonator 1PA at f1r is approximately 20°.
  • the first parallel resonator 1PA includes the parallel wiring PL-1 closest to Tin among the plurality of parallel wirings PL-1 to PL-4, and Tout may be connected to any PL except the parallel wiring PL-4 closest to the .
  • the first parallel resonator 1PA is connected to PL-2.
  • the ripples may adversely affect impedance matching between the acoustic wave filter 100A and an external device. Therefore, by locating the first parallel resonator 1PA as described above, it is possible to reduce the possibility that the first ripple adversely affects the impedance matching with the external device. Therefore, it is possible to realize the elastic wave filter 100A that facilitates impedance matching with an external device.
  • FIG. 5 is a plan view showing one configuration example of the resonator 1 (acoustic wave element) according to one aspect of the present disclosure.
  • FIG. 5 shows a SAW (Surface Acoustic Wave) element as an example of the acoustic wave element.
  • the orthogonal coordinate system (xyz coordinate system) shown in FIG. 5 is introduced for convenience.
  • the x-direction in the example of Embodiment 1 is the propagation direction of elastic waves.
  • the y-direction is an example of a direction crossing the x-direction in the plan view.
  • FIG. 6 is a cross-sectional view taken along line Ic-Ic in FIG. As shown in FIG. 6, the z-direction in the example of Embodiment 1 is the thickness direction of each member of the resonator 1 .
  • the thickness s in FIG. 6 is the thickness of the electrode fingers 32 described below.
  • the term "upper surface" is used with the positive side in the z direction being the upper side.
  • the elastic wave according to one aspect of the present disclosure is not limited to SAW.
  • the elastic wave may be a wave that can be conceptualized in a propagation direction along the piezoelectric substrate of the elastic wave element.
  • the elastic wave may be BAW (Bulk Acoustic Wave), for example. Therefore, another example of the acoustic wave device according to one aspect of the present disclosure is a BAW device. Therefore, the elastic wave filter according to one aspect of the present disclosure may be a SAW filter or a BAW filter.
  • the resonator 1 includes (i) a piezoelectric substrate 2, (ii) an IDT (Interdigital Transducer) electrode 3 provided on an upper surface 2A of the piezoelectric substrate 2, and (iii) a pair of reflectors 4A corresponding to the IDT electrodes. and 4B.
  • the IDT electrodes are also called excitation electrodes.
  • Each of reflectors 4A and 4B is also generically referred to as reflector 4 in this specification.
  • the reflectors 4 may be positioned so as to sandwich the IDT electrodes 3 in the x-direction.
  • the piezoelectric substrate 2 may be composed of a piezoelectric monocrystalline substrate.
  • the piezoelectric substrate 2 may be composed of a single crystal of lithium niobate (LiNbO 3 ) or lithium tantalate (LiTaO 3 ).
  • the IDT electrode 3 may have a first comb-teeth electrode 30a and a second comb-teeth electrode 30b.
  • the first comb-teeth electrode 30 a and the second comb-teeth electrode 30 b are also collectively referred to as the comb-teeth electrode 30 .
  • each member corresponding to the first comb-teeth electrode is appropriately suffixed with a, and each member corresponding to the second comb-teeth electrode is appropriately suffixed with b.
  • Generic names corresponding to the comb-teeth electrodes 30 are used appropriately for these members as well.
  • the comb-teeth electrode 30 includes (i) two busbars 31 facing each other in the y direction and (ii) one busbar 31 (eg, first busbar 31a) to the other busbar 31 (eg, second busbar 31a) in the y direction. 2 and a plurality of electrode fingers 32 extending toward the busbar 31b) side. Then, as shown in FIG. 6, the first electrode fingers 32a and the second electrode fingers 32b may be alternately and repeatedly positioned on the upper surface 2A of the piezoelectric substrate 2 so as to have substantially constant intervals in the x direction. (See also Figure 7).
  • FIG. 7 is an enlarged plan view of a part of the IDT electrode 3 (for example, the central portion 3a of the IDT electrode 3) in FIG.
  • the comb-teeth electrode 30 may have dummy electrode fingers 33 facing each electrode finger 32 . As shown in FIG. 7, the first dummy electrode fingers 33a may extend from the first busbars 31a toward the second electrode fingers 32b. The second dummy electrode fingers 33b may extend from the second busbar 31b toward the first electrode fingers 32a. However, the comb-teeth electrode 30 does not necessarily have to have the dummy electrode fingers 33 .
  • the bus bar 31 may be formed in an elongated shape that has a substantially constant width in the x direction and extends linearly in the x direction. Therefore, the edges of the busbars 31 facing each other may be straight.
  • the plurality of electrode fingers 32 may be formed, for example, in an elongated shape having a substantially constant width in the x direction and linearly extending in the y direction.
  • the plurality of electrode fingers 32 of the IDT electrode 3 may have a pitch Pt1 in the x direction.
  • Pt1 is, for example, the pitch (repeating interval) between the centers of the electrode fingers 32 . Therefore, Pt1 can also be expressed as the pitch from the center of the first electrode finger 32a to the center of the second electrode finger 32b adjacent to the first electrode finger 32a.
  • Pt1 may be set equal to half the wavelength ⁇ ( ⁇ /2) of the elastic wave excited by the IDT electrode 3 . In this case, ⁇ can be expressed as 2 ⁇ Pt1.
  • the plurality of electrode fingers 32 may have a width w1 in the x direction.
  • w1 may be appropriately set according to the electrical characteristics required for the resonator 1 and the like.
  • w1 may be set such that the ratio of w1 to Pt1 (w1/Pt) is a numerical value within a predetermined range.
  • the IDT electrode 3 may be composed of, for example, a conductive layer 15 made of metal.
  • a protective layer 5 may be provided on the piezoelectric substrate 2 so as to cover the IDT electrodes 3 and reflectors 4 (not shown in FIG. 6).
  • the reflector 4 has (i) two reflector busbars 41 facing each other in the y-direction and (ii) a plurality of reflector electrode fingers 42 extending in the y-direction between the reflector busbars 41. It's okay.
  • the reflector bus bar 41 may have, for example, a long shape that has a substantially constant width in the x direction and extends linearly in the x direction.
  • the plurality of reflector electrode fingers 42 may be formed, for example, in an elongated shape having a substantially constant width in the x direction and linearly extending in the y direction.
  • FIG. 8 is a partially enlarged plan view of the reflector 4 in FIG.
  • the plurality of reflector electrode fingers 42 may have a pitch Pt2 in the x-direction.
  • Pt2 may be, for example, the pitch between the centers of the reflector electrode fingers 42 . Therefore, Pt1 can also be expressed as the distance from the center of one reflector electrode finger 42 to the center of the adjacent reflector electrode finger 42 .
  • the multiple electrode fingers 32 may have a width w2 in the x direction. w2 may be set to a value comparable to w1. As an example, w2 may be set equal to w1.
  • the reflector 4 may be configured to reflect the elastic wave excited by the IDT electrode 3 . Therefore, Pt2 may be set to a value approximately equal to Pt1. As an example, Pt2 may be set equal to Pt1. Additionally, as shown in FIG. 5 above, the reflector 4 may be positioned a distance G away from the IDT electrode 3 .
  • the distance G is, for example, (i) from the center of the electrode finger 32 located at the end of the reflector 4 (eg, reflector 4A) where the IDT electrode 3 is located, and (ii) from the IDT electrode 3 side of the reflector 4. to the center of the reflector electrode finger 42 located at the end of .
  • Pt1 is set to the first pitch a1.
  • Pt2 and G are also set equal to a1. That is, the first embodiment exemplifies the case where the normal parallel resonator 1PN has only the first pitch as the electrode finger pitch.
  • the electrode finger pitch in this specification generically refers to Pt, Pt2, and the interval G. According to this configuration, a normal parallel resonator 1PN having no resonant ripple is realized.
  • the first parallel resonator 1PA includes: (i) a first region having a first pitch a1 as an electrode finger pitch of the first parallel resonator 1PA; and a second region having two pitches b1.
  • the region REGa1 shown in FIG. 7 is an example of the first region
  • the region REG1b shown in FIG. 8 is an example of the second region.
  • a1 0.9882 ⁇ m
  • b1 0.7313 ⁇ m. That is, in the example of Embodiment 1, the second pitch is 0.74 times as long as the first pitch.
  • the first parallel resonator 1PA may have only two electrode finger pitches.
  • the electrode finger pitch of the first parallel resonator 1PA may be only two pitches, the first pitch and the second pitch. According to this configuration, it is possible to realize the first parallel resonator 1PA having only the first resonance ripple as a single resonance ripple.
  • the first pitch and the second pitch may be respectively referred to as the main pitch and the minor pitch of the first parallel resonator 1PA.
  • the first area and the second area can exist at arbitrary positions of the first parallel resonator 1PA.
  • the first region may be located within the IDT electrode 3 .
  • the second region may be located within the reflector 4, as shown in FIG.
  • the spacing G is set equal to a1
  • the second region can be positioned within the reflector 4 by setting Pt2 equal to b1.
  • the second region may be located between the IDT electrode 3 and the reflector 4 .
  • Pt2 is set equal to a1
  • the second region can be positioned between the IDT electrode 3 and the reflector 4 by setting the spacing G equal to b1.
  • the second region is formed by two or more electrode fingers (generically referring to the electrode fingers of the IDT electrodes and the electrode fingers of the reflector).
  • the second region is positioned within the IDT electrode 3, there is concern that the performance of the first parallel resonator 1PA, such as power handling, may be adversely affected. Therefore, by locating the second region within the reflector 4 or between the IDT electrode 3 and the reflector 4, the risk of the adverse effects occurring can be reduced.
  • FIG. 9 is a diagram showing the configuration of the main part of the acoustic wave filter 100B of Embodiment 2.
  • the elastic wave filter 100B may include a second parallel resonator 1PB having a second resonance ripple as one of the other parallel resonators.
  • the second parallel resonator 1PB may have frequency characteristics different from those of the first parallel resonator 1PA and the normal parallel resonator 1PN.
  • the second parallel resonator 1PB in the example of FIG. 9 is the parallel resonator 1P-3. Therefore, the normal parallel resonator 1PN in the example of FIG. 9 is parallel resonators 1P-1 and 1P-4.
  • FIG. 10 illustrates attenuation characteristics of each of the acoustic wave filters 100B and 100A.
  • the horizontal axis indicates frequency
  • the vertical axis indicates attenuation.
  • the solid line indicates the characteristic of the elastic wave filter 100B (second embodiment)
  • the dotted line indicates the characteristic of the elastic wave filter 100A (first embodiment).
  • the characteristics of the acoustic wave filter 100A shown in FIG. 10 are equivalent to those in FIG.
  • the elastic wave filter 100B in the example of the second embodiment further includes the second parallel resonator 1PB as the parallel resonator 1P, unlike the elastic wave filter 100A.
  • the elastic wave filter 100B unlike the elastic wave filter 100A, a second resonance ripple due to the second parallel resonator 1PB occurs.
  • the second resonance ripple may be located between the main resonance frequency f2a and the anti-resonance frequency f2b of the second parallel resonator 1PB. Examples of f2a and f2b are described below with reference to FIG. As shown in FIG. 10, in the acoustic wave filter 100B, the steepness of the attenuation characteristic in the transition band is further improved by the second resonance ripple.
  • the second resonance ripple may be located on the lower frequency side than the first resonance ripple.
  • the frequency f2r of the second resonance ripple may be set lower than f1r. Therefore, the second parallel resonator 1PB may be configured to satisfy these conditions.
  • the steepness of the attenuation characteristic in the transition region on the low frequency side can be further improved by the second resonance ripple.
  • FIG. 11 illustrates frequency characteristics of each of the second parallel resonator 1PB and the first parallel resonator 1PA.
  • the solid line indicates the characteristics of the second parallel resonator 1PB
  • the dotted line indicates the characteristics of the first parallel resonator 1PA.
  • the characteristics of the first parallel resonator 1PA shown in FIG. 11 are equivalent to those in FIG.
  • each plot showing the characteristics of the second parallel resonator 1PB is shifted by +5.7 MHz on the horizontal axis for comparison with the characteristics of the first parallel resonator 1PA.
  • the graph denoted by reference numeral 11000A shows impedance characteristics of each of the second parallel resonator 1PB and the first parallel resonator 1PA.
  • a graph denoted by reference numeral 11000B indicates phase characteristics of each of the second parallel resonator 1PB and the first parallel resonator 1PA.
  • f2a 1939.6 MHz
  • f2b 2010.0 MHz
  • f2r 1956.0 MHz.
  • the phase (impedance phase) of the second parallel resonator 1PB may be 50° or less.
  • the steepness of the attenuation characteristic in the transition region on the low frequency side can be further improved in the elastic wave filter 100B.
  • the phase of the second parallel resonator 1PB at f2r is approximately 20°.
  • ⁇ f1 The difference between f1r and f1a is represented herein as ⁇ f1.
  • ⁇ f2 the difference between f2r and f2a is expressed as ⁇ f2.
  • ⁇ f1 f1r ⁇ f1a
  • the second parallel resonator 1PB includes the parallel wiring PL-1 closest to Tin and the parallel wiring PL-4 closest to Tout among the plurality of parallel wirings PL-1 to PL-4. It may be connected to some PL except In the example of FIG. 9, the second parallel resonator 1PB is connected to PL-3. According to the said structure, the elastic wave filter 100B with easy impedance matching with an external device can be implement
  • the second parallel resonator 1PB includes (i) a third region having a third pitch a2 as the electrode finger pitch of the second parallel resonator 1PB, and (ii) a third region having the electrode finger pitch smaller than the third pitch. and a fourth region having 4 pitches b2.
  • the region REGa2 shown in FIG. 7 is an example of a third region
  • the region REGa2 shown in FIG. 8 is an example of a fourth region. According to this configuration, it is possible to realize the second parallel resonator 1PB having the second resonance ripple.
  • the second parallel resonator 1PB may have only two electrode finger pitches.
  • the second parallel resonator 1PB may have only two electrode finger pitches, the third pitch and the fourth pitch.
  • the third and fourth pitches may also be referred to as the main and minor pitches of the second parallel resonator 1PB, respectively.
  • the third and fourth regions in the second parallel resonator 1PB can exist at arbitrary positions in the second parallel resonator 1PB.
  • the third region may be located within the IDT electrode 3 .
  • the fourth region may be located within the reflector 4 or between the IDT electrode 3 and the reflector 4 .
  • FIG. 12 is a diagram illustrating a schematic configuration of the communication device 151 according to the third embodiment.
  • the communication device 151 is an application example of an elastic wave filter according to an aspect of the present disclosure, and performs wireless communication using radio waves.
  • the communication device 151 may include an elastic wave filter (eg, elastic wave filter 100A) according to one aspect of the present disclosure.
  • the communication device 151 may include the demultiplexer 101 configured by the elastic wave filter.
  • the communication device 151 in the example of FIG. 12 may include one branching filter 101 as the transmission filter 109 and another branching filter 101 as the reception filter 111 .
  • a transmission information signal TIS including information to be transmitted is modulated and frequency-increased (converted into a high-frequency signal having a carrier frequency) by an RF-IC (Radio Frequency-Integrated Circuit) 153, and the transmission signal may be converted to TS.
  • the bandpass filter 155 may remove unnecessary components other than the passband for transmission from the TS.
  • the TS from which unnecessary components have been removed may be amplified by amplifier 157 and input to transmission filter 109 .
  • the transmission filter 109 may remove unnecessary components outside the transmission passband from the input transmission signal TS.
  • the transmission filter 109 may output the TS from which unnecessary components have been removed to the antenna 159 .
  • the antenna 159 may convert the TS, which is an electric signal input to itself, into radio waves as radio signals, and transmit the radio waves to the outside of the communication device 151 .
  • the antenna 159 A received radio wave from the outside may be converted into a reception signal RS, which is an electric signal, and the RS may be input to the reception filter 111 .
  • the reception filter 111 may remove unnecessary components outside the reception passband from the input RS.
  • the receive filter 111 may output to the amplifier 161 the receive signal RS from which the unnecessary components have been removed.
  • the output RS may be amplified by amplifier 161 .
  • the bandpass filter 163 may remove unnecessary components other than the reception passband from the amplified RS.
  • the RF-IC 153 may frequency-reduce and demodulate the RS from which unnecessary components have been removed, and convert it into a received information signal RIS.
  • the TIS and RIS may be low frequency signals (baseband signals) containing appropriate information.
  • the TIS and RIS may be analog audio signals or digitized audio signals.
  • the pass band of the radio signal may be set appropriately and may conform to various known standards.

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  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

La présente invention améliore la pente des caractéristiques d'atténuation d'un filtre à ondes acoustiques. Ce filtre à ondes acoustiques comprend : une pluralité de résonateurs en série ; et une pluralité de résonateurs parallèles comprenant un premier résonateur parallèle ayant une première ondulation de résonance, et d'autres résonateurs parallèles. La première ondulation de résonance est positionnée entre une fréquence de résonance principale et une fréquence anti-résonance du premier résonateur parallèle. La fréquence de résonance principale du premier résonateur parallèle est supérieure à la fréquence de résonance principale d'au moins un résonateur parallèle parmi les autres résonateurs parallèles.
PCT/JP2023/003202 2022-02-03 2023-02-01 Filtre à ondes acoustiques et dispositif de communication WO2023149471A1 (fr)

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WO2017068838A1 (fr) * 2015-10-23 2017-04-27 株式会社村田製作所 Dispositif de filtre à ondes élastiques
WO2018030277A1 (fr) * 2016-08-09 2018-02-15 株式会社村田製作所 Multiplexeur, circuit frontal haute fréquence et dispositif de communication
JP2020123819A (ja) * 2019-01-30 2020-08-13 株式会社村田製作所 弾性波フィルタ
JP2021082910A (ja) * 2019-11-18 2021-05-27 株式会社村田製作所 複合フィルタ装置

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