WO2022014332A1 - Filtre à ondes élastiques et multiplexeur - Google Patents

Filtre à ondes élastiques et multiplexeur Download PDF

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Publication number
WO2022014332A1
WO2022014332A1 PCT/JP2021/024754 JP2021024754W WO2022014332A1 WO 2022014332 A1 WO2022014332 A1 WO 2022014332A1 JP 2021024754 W JP2021024754 W JP 2021024754W WO 2022014332 A1 WO2022014332 A1 WO 2022014332A1
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Prior art keywords
comb
elastic wave
shaped
electrodes
electrode
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PCT/JP2021/024754
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English (en)
Japanese (ja)
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普一 中村
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株式会社村田製作所
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Publication of WO2022014332A1 publication Critical patent/WO2022014332A1/fr

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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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • H03H9/72—Networks using surface acoustic waves

Definitions

  • the present invention relates to an elastic wave filter and a multiplexer.
  • Patent Document 1 discloses an elastic wave filter including a filter circuit having a predetermined frequency band as a pass band and a loop circuit connected in parallel to the filter circuit.
  • a loop circuit is used to apply an antiphase to unnecessary waves outside the pass band, cancel unnecessary waves, and increase the amount of attenuation outside the pass band.
  • this elastic wave filter it is difficult to adjust the phase and the like by the loop circuit, and it may not be possible to secure a sufficient amount of attenuation outside the pass band.
  • the present invention has been made to solve the above problems, and an object of the present invention is to provide an elastic wave filter or the like that can secure an amount of attenuation outside the frequency passband.
  • the elastic wave filter has a predetermined frequency band as a passing band and is arranged on a first path connecting the first signal terminal and the second signal terminal.
  • a first filter circuit and an additional circuit having an elastic wave resonator group and being connected to a plurality of nodes on the first path are provided, and the elastic wave resonator group is along the elastic wave propagation direction.
  • the plurality of IDT electrodes have a plurality of first comb-shaped electrodes and a plurality of second comb-shaped electrodes, the first comb-shaped electrode and the first comb-shaped electrode.
  • the two comb-shaped electrodes are opposed to each other, and the plurality of first comb-shaped electrodes are electrically connected to the plurality of nodes, and some of the plurality of second comb-shaped electrodes are connected to each other.
  • the second comb-shaped electrode is connected to the ground, and the other second comb-shaped electrode different from the part of the second comb-shaped electrode is not connected to the ground and is open.
  • the multiplexer has a pass band of the elastic wave filter, the first signal terminal, the second signal terminal and the third signal terminal, and a frequency band different from that of the first filter circuit.
  • a second filter circuit arranged on a third path connecting the second signal terminal and the third signal terminal is provided.
  • the elastic wave filter or the like according to the present invention, it is possible to secure the amount of attenuation outside the frequency passband.
  • FIG. 1 is a circuit configuration diagram of a multiplexer including an elastic wave filter according to an embodiment.
  • FIG. 2 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the embodiment.
  • FIG. 3 is a plan view and a cross-sectional view schematically showing the structure of the elastic wave resonator group shown in FIG.
  • FIG. 4 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter of the comparative example.
  • FIG. 5 is a diagram showing the passage characteristics of the elastic wave filter according to the embodiment.
  • FIG. 6 is a diagram showing the isolation characteristics of the multiplexer according to the embodiment.
  • FIG. 7 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the first modification of the embodiment.
  • FIG. 8 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the second modification of the embodiment.
  • FIG. 9 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the third modification of the embodiment.
  • FIG. 10 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the modified example 4 of the embodiment.
  • FIG. 11 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the modified example 5 of the embodiment.
  • FIG. 12 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the modified example 6 of the embodiment.
  • FIG. 13 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the modified example 7 of the embodiment.
  • FIG. 14 is a schematic diagram showing a group of elastic wave resonators included in the additional circuit of the elastic wave filter according to the modified example 8 of the embodiment.
  • FIG. 1 is a circuit configuration diagram of a multiplexer 5 including the elastic wave filter 1 according to the embodiment. Note that FIG. 1 also shows the antenna element 9.
  • the multiplexer 5 is a demultiplexer or combiner including a plurality of filters having different frequency pass bands. As shown in FIG. 1, the multiplexer 5 includes an elastic wave filter 1 having a first filter circuit 10 and an additional circuit 20, and a second filter circuit 50. Further, the multiplexer 5 includes a first signal terminal T1, a second signal terminal T2, and a third signal terminal T3.
  • the first signal terminal T1 is connected to the elastic wave filter 1. Further, the first signal terminal T1 is connected to an RF signal processing circuit (not shown) via an amplifier circuit or the like (not shown) outside the multiplexer 5.
  • the second signal terminal T2 is a common terminal connected to each of the elastic wave filter 1 and the second filter circuit 50. Specifically, the second signal terminal T2 is connected to the elastic wave filter 1 via the node n0 between the elastic wave filter 1 and the second signal terminal T2, and is also connected to the elastic wave filter 1 via the node n0. It is connected to 50. Further, the second signal terminal T2 is connected to the antenna element 9 outside the multiplexer 5. The second signal terminal T2 is also an antenna terminal of the multiplexer 5.
  • the third signal terminal T3 is connected to the second filter circuit 50. Further, the third signal terminal T3 is connected to an RF signal processing circuit (not shown) via an amplifier circuit or the like (not shown) outside the multiplexer 5.
  • the elastic wave filter 1 is arranged on the first path r1 connecting the first signal terminal T1 and the second signal terminal T2.
  • the elastic wave filter 1 is, for example, a transmission filter having an uplink frequency band (transmission band) as a pass band, and is set so that the frequency pass band is lower than that of the second filter circuit 50.
  • the elastic wave filter 1 includes a first filter circuit 10 and an additional circuit 20 additionally connected to the first filter circuit 10.
  • the additional circuit 20 is a circuit for canceling unnecessary waves outside the frequency pass band of the first filter circuit 10. The additional circuit 20 will be described later.
  • the second filter circuit 50 is arranged on the third path r3 connecting the second signal terminal T2 and the third signal terminal T3.
  • the second filter circuit 50 is, for example, a reception filter having a downlink frequency band (reception band) as a pass band.
  • the second filter circuit 50 is composed of, for example, a series arm resonator RS1 and a plurality of vertically coupled elastic wave resonators 60.
  • Each of the elastic wave filter 1 and the second filter circuit 50 is required to have a characteristic of passing through a predetermined frequency band and attenuating a band outside the frequency band.
  • the elastic wave filter 1 includes a first filter circuit 10 and an additional circuit 20.
  • the first filter circuit 10 includes series arm resonators S1, S2, S3, S4 and parallel arm resonators P1, P2, P3, and P4, which are elastic wave resonators.
  • the series arm resonators S1 to S4 are arranged on the first path (series arm) r1 connecting the first signal terminal T1 and the second signal terminal T2.
  • the series arm resonators S1 to S4 are connected in series from the first signal terminal T1 toward the second signal terminal T2 in this order.
  • the parallel arm resonators P1 to P4 are paths (parallel) connecting the nodes n1, n2, n3, n4 between the adjacent series arm resonators S1 to S4 on the first path r1 and the reference terminal (ground). Arms) are connected in parallel to each other. Specifically, among the parallel arm resonators P1 to P4, the parallel arm resonator P1 closest to the first signal terminal T1 is connected to the node n1 between the series arm resonators S1 and S2. The parallel arm resonator P2 is connected to the node n2 between the series arm resonators S1 and S2. The parallel arm resonator P3 is connected to the node n3 between the series arm resonators S2 and S3. The parallel arm resonator P4 is connected to the node n4 between the series arm resonators S3 and S4.
  • the first filter circuit 10 is arranged on the four series arm resonators S1 to S4) arranged on the first path r1 and on the path connecting the first path r1 and the reference terminal. It has a T-shaped ladder filter structure composed of four parallel arm resonators P1 to P4).
  • the number of series arm resonators and parallel arm resonators constituting the first filter circuit 10 is not limited to four, respectively, and may be two or more series arm resonators and one or more parallel arm resonators. Just do it.
  • the parallel arm resonator may be connected to the reference terminal via an inductor.
  • an impedance element such as an inductor and a capacitor may be inserted or connected on the series arm or the parallel arm.
  • the reference terminal (ground) to which the parallel arm resonators are connected is standardized, but whether the reference terminal is standardized or individualized depends on, for example, the mounting layout of the first filter circuit 10. It can be appropriately selected due to restrictions and the like.
  • the additional circuit 20 is a circuit that suppresses the output of unnecessary waves from the elastic wave filter 1 by applying an antiphase to unnecessary waves outside the frequency passband generated by the first filter circuit 10.
  • the additional circuit 20 is connected to a plurality of different nodes on the first path r1 so as to be connected in parallel to all or part of the first filter circuit 10.
  • the additional circuit 20 includes a first terminal 21 that is a connection node on one end side of the additional circuit 20, a second terminal 22 that is a connection node on the other end side, and a second terminal that connects the first terminal 21 and the second terminal 22. It has an elastic wave resonator group 25 arranged on the path r2 of the above.
  • the terminal here means an inlet or an outlet of a high frequency signal.
  • the first terminal 21 is electrically connected to the elastic wave resonator group 25 via the capacitive element C1.
  • the second terminal 22 is connected to the elastic wave resonator group 25 via the capacitive element C2.
  • the first terminal 21 and the second terminal 22 are acoustically connected via the elastic wave resonator group 25.
  • each of the first terminal 21 and the second terminal 22 is connected to a different node on the first path r1.
  • the first terminal 21 is connected to the node n1 between the series arm resonators S1 and S2
  • the second terminal 22 is the node n5 between the series arm resonator S4 and the second signal terminal T2. It is connected to the.
  • FIG. 2 is a schematic diagram showing an elastic wave resonator group 25 included in the additional circuit 20 of the elastic wave filter 1.
  • the electrodes and the wiring are shown by solid lines.
  • the elastic wave resonator group 25 includes a plurality of IDT (InterDigital Transducer) electrodes 31 and 32.
  • the elastic wave resonator group 25 is, for example, a vertically coupled resonator.
  • the plurality of IDT electrodes 31 and 32 are arranged adjacent to each other along the elastic wave propagation direction D1.
  • the electrode parameters of the plurality of IDT electrodes 31 and 32 are different from each other.
  • the additional circuit 20 has a plurality of reflectors 40.
  • the plurality of reflectors 40 are arranged on both outer sides of the plurality of IDT electrodes 31 and 32 so as to sandwich the plurality of IDT electrodes 31 and 32 in the elastic wave propagation direction D1.
  • FIG. 2 illustrates an additional circuit 20 with two IDT electrodes 31, 32 and two reflectors 40.
  • the plurality of IDT electrodes 31 and 32 have a plurality of first comb-shaped electrodes 31a and 32a and a plurality of second comb-shaped electrodes 31b and 32b.
  • one of the IDT electrodes 31 is composed of a pair of a first comb-shaped electrode 31a and a second comb-shaped electrode 31b.
  • the other IDT electrode 32 is composed of a pair of a first comb-shaped electrode 32a and a second comb-shaped electrode 32b.
  • the first comb-shaped electrode 31a and the second comb-shaped electrode 31b face each other.
  • the first comb-shaped electrode 32a and the second comb-shaped electrode 32b face each other.
  • the first comb-shaped electrodes 31a and 32a are arranged in the same direction.
  • the second comb-shaped electrodes 31b and 32b are arranged in the same direction as each other and in the opposite directions to the first comb-shaped electrodes 31a and 32a.
  • the first comb-shaped electrode 31a is a part of the first comb-shaped electrode
  • the first comb-shaped electrode 32a is a part of the first comb.
  • Another first comb-shaped electrode different from the tooth-shaped electrode 31a is used.
  • the second comb-shaped electrode 31b is used as a part of the second comb-shaped electrode
  • the second comb-shaped electrode 32b is used as a part of the second comb-shaped electrode.
  • a second comb-shaped electrode different from the shaped electrode 31b is used.
  • the plurality of first comb-shaped electrodes 31a and 32a are electrically connected to a plurality of different nodes on the first path r1. Specifically, a part of the first comb-shaped electrode 31a is connected to the node n1 by the first terminal 21, and the other first comb-shaped electrode 32a is connected to the node n5 by the second terminal 22. ..
  • the phase of the additional circuit 20 is adjusted. It is possible to widen the adjustment range of. As a result, it is possible to suppress unnecessary waves outside the frequency passband of the elastic wave filter 1 and secure an amount of attenuation outside the frequency passband.
  • first terminal 21 of the additional circuit 20 is connected to the node n1 and the second terminal 22 is connected to the node n5, but the present invention is not limited to this.
  • Each of the first terminal 21 and the second terminal 22 may be connected to the outer nodes of two or more series arm resonators adjacent to each other on the first path r1.
  • the first terminal 21 may be connected to a node on the first path r1 connecting the first signal terminal T1 and the series arm resonator S1, or may be connected to the node n3.
  • the second terminal 22 may be connected to the node n3 or the node n4.
  • the additional circuit 20 does not have to include the capacitive elements C1 and C2.
  • the elastic wave resonator group 25 may be connected to each of the first terminal 21 and the second terminal 22 by wiring without a capacitive element, as long as the unnecessary wave can be appropriately suppressed.
  • the surface acoustic wave resonator group 25 is composed of, for example, a plurality of surface acoustic wave (SAW) resonators.
  • FIG. 3 is a plan view and a cross-sectional view schematically showing the structure of the elastic wave resonator group 25.
  • the elastic wave resonator shown in FIG. 3 is for explaining a typical structure of the resonator, and the number and length of the electrode fingers constituting the comb-shaped electrode are included in this. Not limited.
  • the elastic wave resonator group 25 is composed of a substrate 320 having piezoelectricity and a plurality of IDT electrodes 31 and 32 formed on the substrate 320.
  • a plurality of reflectors 40 are provided on both outer sides of the plurality of IDT electrodes 31 and 32 in the elastic wave propagation direction D1.
  • the elastic wave resonator group 25 is placed on the substrate 320 so as to cover the substrate 320, the electrode layer 325 constituting the IDT electrodes 31 and 32, and the IDT electrodes 31 and 32. It is formed by the provided dielectric layer 326. Since the cross-sectional structure of the reflector 40 is the same as the cross-sectional structure of the IDT electrodes 31 and 32, the description thereof will be omitted below.
  • the substrate 320 is, for example, a LiNbO 3 substrate (lithium niobate substrate) having a cut angle of 127.5 °.
  • the cut angle of the substrate 320 is preferably 120 ° ⁇ 20 ° or 300 ° ⁇ 20 °.
  • the electrode layer 325 has a structure in which a plurality of metal layers are laminated.
  • the electrode layer 325 is formed by, for example, laminating a Ti layer, an Al layer, a Ti layer, a Pt layer, and a NiCr layer in order from the top.
  • the dielectric layer 326 is, for example, a film containing silicon dioxide (SiO 2 ) as a main component.
  • the dielectric layer 326 is provided for the purpose of adjusting the frequency and temperature characteristics of the elastic wave resonator group 25, protecting the electrode layer 325 from the external environment, or enhancing the moisture resistance.
  • the IDT electrode 31 has a pair of first comb-shaped electrodes 31a and second comb-shaped electrodes 31b facing each other.
  • the IDT electrode 32 has a pair of first comb-shaped electrodes 32a and second comb-shaped electrodes 32b facing each other.
  • Each of the first comb-shaped electrodes 31a and 32a has a comb-shaped shape and is composed of a plurality of electrode fingers 36a parallel to each other and a bus bar electrode 37a connecting one ends of the plurality of electrode fingers 36a to each other.
  • Each of the second comb-shaped electrodes 31b and 32b has a comb-tooth shape and is composed of a plurality of electrode fingers 36b parallel to each other and a bus bar electrode 37b connecting one ends of the plurality of electrode fingers 36b to each other. ing.
  • the plurality of electrode fingers 36a and 36b are formed so as to extend in the orthogonal direction D2 of the elastic wave propagation direction D1, intersperse with each other in the orthogonal direction D2, and face the elastic wave propagation direction D1.
  • the pitches (distances) of the plurality of electrode fingers 36a in the elastic wave propagation direction D1 are different between the IDT electrode 31 and the IDT electrode 32. Further, the pitches (distances) of the plurality of electrode fingers 36b in the elastic wave propagation direction D1 are different between the IDT electrode 31 and the IDT electrode 32.
  • the bus bar electrodes 37a and 37b are formed so as to extend along the elastic wave propagation direction D1.
  • a lead-out wiring d1a is connected to the bus bar electrode 37a of the first comb-shaped electrode 31a.
  • the first comb-shaped electrode 31a is connected to the first terminal 21 via the lead-out wiring d1a and the capacitive element C1.
  • a lead-out wiring d2a is connected to the bus bar electrode 37a of the first comb-shaped electrode 32a.
  • the first comb-shaped electrode 32a is connected to the second terminal 22 via the lead-out wiring d2a and the capacitive element C2.
  • a lead-out wiring d1b is connected to the bus bar electrode 37b of the second comb-shaped electrode 31b.
  • the second comb-shaped electrode 31b is connected to the ground via the lead-out wiring d1b.
  • the ground may be a ground connection electrode (not shown) provided on the substrate of the multiplexer 5.
  • the lead-out wiring is not connected to the bus bar electrode 37b of the second comb-shaped electrode 32b, and the second comb-shaped electrode 32b is in an electrically float state, that is, an open state.
  • the plurality of reflectors 40 are arranged so as to sandwich the IDT electrodes 31 and 32 in the elastic wave propagation direction D1.
  • Each reflector 40 is composed of a plurality of reflective electrode fingers parallel to each other and a reflective bus bar electrode connecting both ends of the plurality of reflective electrode fingers.
  • the plurality of reflective electrode fingers are formed so as to extend in the orthogonal direction D2 of the elastic wave propagation direction D1.
  • the reflector 40 shown in FIG. 3 is in an open state, but the present invention is not limited to this, and the reflector 40 may be connected to the ground or may be connected to a hot terminal (signal terminal).
  • the elastic wave filter of the comparative example includes a first filter circuit 10 and an additional circuit 120 additionally connected to the first filter circuit 10.
  • FIG. 4 is a schematic diagram showing an elastic wave resonator group 125 included in the additional circuit 120 of the elastic wave filter of the comparative example.
  • the elastic wave resonator group 125 of the comparative example is composed of a plurality of IDT electrodes, and all of the plurality of second comb-shaped electrodes 31b and 32b are connected to the ground.
  • FIG. 5 is a diagram showing the passing characteristics of the elastic wave filter 1.
  • FIG. 6 is a diagram showing the isolation characteristics of the multiplexer 5.
  • the elastic wave filter 1 is used as a transmission filter
  • the second filter circuit 50 is used as a reception filter
  • the frequency passband of the elastic wave filter 1 is set to 703 MHz to 733 MHz
  • the frequency passband of the second filter circuit 50 is set. Is shown as an example in which 758 MHz to 788 MHz is set.
  • FIG. 5 shows an insertion loss between the first signal terminal T1 and the second signal terminal T2
  • FIG. 6 shows the insertion loss between the first signal terminal T1 and the third signal terminal T3. There is.
  • the peak of the insertion loss is 37 dB in the frequency pass band of the second filter circuit 50, and the attenuation amount is compared with 33 dB, which is the peak of the insertion loss in the comparative example. Is getting bigger.
  • the peak of the insertion loss is 39 dB in the frequency pass band of the second filter circuit 50, which is compared with the peak of the insertion loss of 36 dB in the comparative example. The isolation characteristics are improved.
  • the frequency of the elastic wave filter 1 is reached. It is possible to secure the amount of attenuation outside the pass band.
  • FIG. 7 is a schematic diagram showing an elastic wave resonator group 25A included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 1.
  • the elastic wave resonator group 25A includes a plurality of IDT electrodes 31 and 32.
  • the plurality of IDT electrodes 31 and 32 have a plurality of first comb-shaped electrodes 31a and 32a and a plurality of second comb-shaped electrodes 31b and 32b.
  • the IDT electrode 31 is composed of a pair of a first comb-shaped electrode 31a and a second comb-shaped electrode 31b.
  • the IDT electrode 32 is composed of a pair of a first comb-shaped electrode 32a and a second comb-shaped electrode 32b.
  • the first comb-shaped electrode 32a is a part of the first comb-shaped electrode, and the first comb-shaped electrode 31a is a part of the first comb-shaped electrode.
  • a first comb-shaped electrode different from the comb-shaped electrode 32a is used.
  • the second comb-shaped electrode 32b is used as a part of the second comb-shaped electrode, and the second comb-shaped electrode 31b is used as a part of the second comb-shaped electrode.
  • a second comb-shaped electrode different from the shaped electrode 32b is used.
  • the part of the second comb-shaped electrode 32b faces the part of the first comb-shaped electrode 32a, and the other second comb-shaped electrode 31b is the other first comb. It is configured to face the dentate electrode 31a. Further, a part of the first comb-shaped electrode 32a is connected to the node n5 by the second terminal 22, and the other first comb-shaped electrode 31a is connected to the node n1 by the first terminal 21.
  • a part of the second comb-shaped electrode 32b is connected to the ground, and the other second comb-shaped electrode 31b is connected to the ground. It is open without being open. Also in the elastic wave filter 1 of the modification 1, at least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25A is in an open state.
  • the elastic wave filter 1 according to the second modification of the embodiment will be described.
  • the second modification an example in which the first comb-shaped electrode 31a and the second comb-shaped electrode 31b of the IDT electrode 31 are arranged in the orthogonal direction D2 in the opposite direction to the embodiment will be described. That is, in the second modification, the direction of the first comb-shaped electrode 31a is opposite to the direction of the first comb-shaped electrode 32a, and the direction of the second comb-shaped electrode 31b is the direction of the second comb-shaped electrode 32b. The opposite. Also in this example, the comb-shaped electrode connected to the first terminal 21 or the second terminal 22 is called the first comb-shaped electrode, and the comb-shaped electrode in the ground-connected state or the open state is the second comb-shaped electrode. Called.
  • FIG. 8 is a schematic diagram showing an elastic wave resonator group 25B included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 2.
  • the elastic wave resonator group 25B includes a plurality of IDT electrodes 31 and 32.
  • the IDT electrode 31 is composed of a pair of a first comb-shaped electrode 31a and a second comb-shaped electrode 31b.
  • the IDT electrode 32 is composed of a pair of a first comb-shaped electrode 32a and a second comb-shaped electrode 32b.
  • first comb-shaped electrodes 31a and 32a Of the plurality of first comb-shaped electrodes 31a and 32a, some of the first comb-shaped electrodes 31a are electrically connected to the first terminal 21, and the other first comb-shaped electrodes 32a are second. It is electrically connected to the terminal 22.
  • the elastic wave filter 1 of the modification 2 at least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25B is in an open state.
  • FIG. 9 is a schematic diagram showing an elastic wave resonator group 25C included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 3.
  • the elastic wave resonator group 25C includes a plurality of IDT electrodes 31 and 32.
  • the IDT electrode 31 is composed of a pair of a first comb-shaped electrode 31a and a second comb-shaped electrode 31b.
  • the IDT electrode 32 is composed of one first comb-shaped electrode 32a and a plurality of second comb-shaped electrodes.
  • FIG. 9 shows two second comb-shaped electrodes 32c and 32d as an example of the plurality of second comb-shaped electrodes.
  • Each of the plurality of second comb-shaped electrodes 32c and 32d faces the first comb-shaped electrode 32a.
  • the plurality of second comb-shaped electrodes 32c and 32d are independent electrodes that are not connected to each other.
  • the second comb-shaped electrode 32c is used as a part of the second comb-shaped electrode
  • the second comb-shaped electrode 32d is used as a part of the second comb.
  • a second comb-shaped electrode different from the tooth-shaped electrode 32c is used.
  • the third modification of the plurality of second comb-shaped electrodes 32c and 32d, a part of the second comb-shaped electrodes 32c is connected to the ground, and the other second comb-shaped electrodes 32d are connected to the ground. It is open without being open.
  • the number of electrode fingers of the second comb-shaped electrode 32d in the open state is smaller than the number of electrode fingers of the second comb-shaped electrodes 31b and 32c in the ground connection state. In other words, the number of electrode fingers is larger in the second comb-shaped electrode in the ground-connected state than in the open state.
  • at least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25C is in an open state.
  • the IDT electrode 32 is composed of one first comb tooth electrode and a plurality of second comb tooth electrodes, but the present invention is not limited to this, and the IDT electrode 31 is 1. It may be composed of one first comb tooth electrode and a plurality of second comb tooth electrodes. Further, although two second comb-tooth electrodes 32c and 32d are exemplified as the plurality of second comb-tooth electrodes, the number of the second comb-tooth electrodes is not limited to that, and may be three or more. The same applies to each of the following modifications.
  • FIG. 10 is a schematic diagram showing an elastic wave resonator group 25D included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 4.
  • the elastic wave resonator group 25D includes a plurality of IDT electrodes 31 and 32.
  • the IDT electrode 31 is composed of a pair of a first comb-shaped electrode 31a and a second comb-shaped electrode 31b.
  • the second comb-shaped electrode 31b is not connected to the ground and is open.
  • the number of electrode fingers of the second comb-shaped electrodes 31b and 32d in the open state is larger than the number of electrode fingers of the second comb-shaped electrodes 32c in the ground connection state. In other words, the number of electrode fingers is smaller in the second comb-shaped electrode in the ground-connected state than in the open state.
  • the second comb-shaped electrode 31c in the ground connection state is arranged between the second comb-shaped electrodes 31b and 32d in the open state. The second comb-shaped electrode 31b is not connected to the other second comb-shaped electrode 32d.
  • at least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25D is in an open state.
  • FIG. 11 is a schematic diagram showing an elastic wave resonator group 25E included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 5.
  • a part of the second comb-shaped electrode 32c is connected to the ground, and the other second comb-shaped electrode 32d is not connected to the ground and is open. Further, the second comb-shaped electrode 31b and the second comb-shaped electrode 32c have a common ground.
  • the common ground is realized, for example, by connecting the lead-out wiring of the second comb-toothed electrode 31b and the pull-out wiring of the second comb-toothed electrode 32c to the ground connection electrode. Further, even if the common ground is realized by connecting the bus bar electrode of the second comb tooth electrode 31b and the bus bar electrode of the second comb tooth electrode 32c to the ground connection electrode. good.
  • At least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25E is in an open state.
  • FIG. 12 is a schematic diagram showing an elastic wave resonator group 25F included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 6.
  • the IDT electrode 32 is composed of one first comb-shaped electrode 32a and a plurality of second comb-shaped electrodes 32c and 32d. Each of the two second comb-shaped electrodes 32c and 32d faces the first comb-shaped electrode 32a.
  • the second comb-shaped electrode 32d is used as a part of the first comb-shaped electrode, and the second comb-shaped electrode 32c is used as a part of the second comb.
  • a second comb-shaped electrode different from the tooth-shaped electrode 32d is used.
  • a part of the second comb-shaped electrodes 32d is connected to the ground, and the other second comb-shaped electrodes 32c are connected to the ground. It is open without being open. Further, the second comb-shaped electrode 31b and the second comb-shaped electrode 32d have a common ground. Further, in this example, the second comb-shaped electrode 31c in the open connection state is arranged between the second comb-shaped electrodes 31b and 32d in the ground-connected state.
  • At least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25F is in an open state.
  • FIG. 13 is a schematic diagram showing an elastic wave resonator group 25G included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 7.
  • the elastic wave resonator group 25G includes a plurality of IDT electrodes 31 and 32.
  • the IDT electrode 31 is composed of one first comb tooth electrode 31a and a plurality of second comb tooth electrodes 31c and 31d
  • the IDT electrode 32 is composed of one first comb tooth electrode 32a and a plurality of second comb tooth electrodes 31c and 31d. It is composed of a plurality of second comb tooth-shaped electrodes 32c and 32d.
  • Each of the two second comb-shaped electrodes 31c and 31d faces the first comb-shaped electrode 31a
  • each of the two second comb-shaped electrodes 32c and 32d faces the first comb-shaped electrode 32a. is doing.
  • a part of the second comb-shaped electrode 31c is connected to the ground, and the other second comb-shaped electrode 31d is connected to the ground. It is open to the public. Further, of the plurality of second comb-shaped electrodes 32c and 32d, a part of the second comb-shaped electrodes 32c is connected to the ground, and the other second comb-shaped electrodes 32d are not connected to the ground and are opened. Has been done. Further, the second comb-shaped electrode 31c and the second comb-shaped electrode 32c have a common ground.
  • At least one of the plurality of second comb-shaped electrodes of the elastic wave resonator group 25G is in an open state.
  • FIG. 14 is a schematic diagram showing an elastic wave resonator group 25H included in the additional circuit 20 of the elastic wave filter 1 according to the modified example 8.
  • the elastic wave resonator group 25H includes a plurality of IDT electrodes 31, 32, 33.
  • the plurality of IDT electrodes 31, 32, 33 have a plurality of first comb-shaped electrodes 31a, 32a, 33a and a plurality of second comb-shaped electrodes 31b, 32b, 33b.
  • the IDT electrode 31 is composed of a pair of a first comb-shaped electrode 31a and a second comb-shaped electrode 31b.
  • the IDT electrode 32 is composed of a pair of a first comb-shaped electrode 32a and a second comb-shaped electrode 32b.
  • the IDT electrode 33 is composed of a pair of a first comb-shaped electrode 33a and a second comb-shaped electrode 33b.
  • the first comb-shaped electrodes 32a, 33a are partially used as the first comb-shaped electrodes, and the first comb-shaped electrodes 31a are partially used.
  • the first comb-shaped electrode is different from the first comb-shaped electrodes 32a and 33a.
  • the second comb-shaped electrodes 32b, 33b are used as a part of the second comb-shaped electrode, and the second comb-shaped electrode 31b is used as a part of the second comb-shaped electrode 31b.
  • Other second comb-shaped electrodes different from the second comb-shaped electrodes 32b and 33b are used.
  • a plurality of first comb-shaped electrodes 31a, 32a, 33a are electrically connected to a plurality of nodes on the first path r1. Specifically, some of the first comb-shaped electrodes 32a and 33a are connected to the node n1 by the first terminal 21, and the other first comb-shaped electrodes 31a are connected to the node n5 by the second terminal 22. Will be done.
  • the second comb-shaped electrodes 32b, 33b are connected to the ground, and the other second comb-shaped electrodes 31b are connected to the ground. It is not connected and is open. In this way, at least one of the plurality of comb-shaped electrodes of the elastic wave resonator group 25H included in the additional circuit 20 is not connected to the ground and is in an open state, so that the phase of the additional circuit 20 is adjusted. It is possible to widen the adjustment range. As a result, it is possible to suppress unnecessary waves outside the frequency passband of the elastic wave filter 1 and secure an amount of attenuation outside the frequency passband.
  • first comb-shaped electrodes 32a and 33a a part of the first comb-shaped electrodes 32a and 33a is connected to the node n1, and another first comb-shaped electrode 31a is connected to the node n5.
  • first comb-shaped electrodes need to be connected to different nodes on the first path r1, but two or more first comb-shaped electrodes that are part of all (eg, 31a, 32a). Is connected to a different node on the first path r1.
  • each comb-shaped electrode is not limited to this.
  • one of a part of the second comb-shaped electrodes 32b and 33b may be open without being connected to the ground.
  • another second comb-shaped electrode 31b may be connected to the ground, and some of the second comb-shaped electrodes 32b and 33b may be open without being connected to the ground.
  • FIG. 14 in FIG. 14, one of a part of the second comb-shaped electrodes 32b and 33b may be open without being connected to the ground.
  • another second comb-shaped electrode 31b may be connected to the ground, and some of the second comb-shaped electrodes 32b and 33b may be open without being connected to the ground.
  • the first comb-shaped electrode 31a is connected to the first terminal 21, the first comb-shaped electrodes 32a and 33a are connected to the second terminal 22, and the second comb-shaped electrode 31b is connected to the ground.
  • the second comb-shaped electrodes 32b and 33b may be open without being connected to the ground.
  • the elastic wave filter 1 has a predetermined frequency band as a pass band and is arranged on the first path r1 connecting the first signal terminal T1 and the second signal terminal T2.
  • a first filter circuit 10 and an additional circuit 20 having an elastic wave resonator group 25 and being connected to a plurality of nodes (for example, n1 and n5) on the first path r1 are provided.
  • the elastic wave resonator group 25 has a plurality of IDT electrodes 31 and 32 arranged along the elastic wave propagation direction D1.
  • the plurality of IDT electrodes 31 and 32 have a plurality of first comb-shaped electrodes (for example, 31a, 32a) and a plurality of second comb-shaped electrodes (for example, 31b, 32b).
  • the first comb-shaped electrode and the second comb-shaped electrode face each other.
  • a part of the first comb-shaped electrodes 31a and 32a (for example, 31a) and another first comb-shaped electrode different from the above-mentioned first comb-shaped electrodes (for example, 31a). 32a) is electrically connected to the plurality of nodes.
  • some of the second comb-shaped electrodes are connected to the ground, and the other second comb-shaped electrodes different from the above-mentioned some second comb-shaped electrodes are It is open without being connected to the ground.
  • each of the plurality of IDT electrodes 31 and 32 may be composed of a pair of first comb-shaped electrodes 31a and 32a and second comb-shaped electrodes 31b and 32b.
  • At least one of the plurality of second comb-shaped electrodes 31b and 32b included in the plurality of IDT electrodes 31 and 32 can be opened without being connected to the ground, and the phase of the additional circuit 20 is adjusted. It is possible to widen the adjustment range. As a result, it is possible to suppress unnecessary waves outside the frequency passband of the elastic wave filter 1 and secure an amount of attenuation outside the frequency passband.
  • the part of the second comb-shaped electrode (for example, 31b) faces the first comb-shaped electrode (for example, 31a), and the other second comb-shaped electrode (for example, 32b) faces the first comb-shaped electrode (for example, 31a).
  • the phase of the additional circuit 20 is adjusted by using the second comb-shaped electrode 32b not connected to the ground and the first comb-shaped electrode 32a facing the second comb-shaped electrode 32b. It becomes possible. As a result, it is possible to suppress unnecessary waves outside the frequency passband of the elastic wave filter 1 and secure an amount of attenuation outside the frequency passband.
  • At least one IDT electrode (for example, 32) among the plurality of IDT electrodes 31 and 32 is provided by one first comb-tooth electrode (for example, 32a) and the plurality of second comb-tooth electrodes (for example, 32c, 32d). It may be configured.
  • At least one of the plurality of second comb-shaped electrodes 32c and 32d included in the IDT electrode 32 can be opened without being connected to the ground, and the phase of the additional circuit 20 can be adjusted. It is possible to widen the adjustment range. As a result, it is possible to suppress unnecessary waves outside the frequency passband of the elastic wave filter 1 and secure an amount of attenuation outside the frequency passband.
  • some of the second comb-shaped electrodes are connected to the ground, and other second comb-shaped electrodes different from some of the second comb-shaped electrodes are connected. May be open without being connected to the ground.
  • some of the second comb-shaped electrodes may be composed of two or more second comb-shaped electrodes (for example, 31b, 32c or 31b, 32d).
  • the second or more second comb-shaped electrodes may be connected to a ground, and the ground may be shared.
  • the phase of the additional circuit 20 can be adjusted accurately. As a result, it is possible to suppress unnecessary waves outside the frequency passband of the elastic wave filter 1 and secure an amount of attenuation outside the frequency passband.
  • the multiplexer 5 has a pass band different from that of the elastic wave filter 1, the first signal terminal T1, the second signal terminal T2, the third signal terminal T3, and the first filter circuit 10.
  • a second filter circuit 50 arranged on a third path r3 connecting the second signal terminal T2 and the third signal terminal T3 is provided.
  • the elastic wave filter is provided with two or three IDT electrodes, but the number of IDT electrodes is not limited to this, and the number of IDT electrodes may be four or five or more.
  • the frequency passband of the elastic wave filter 1 is set to be lower than the frequency passband of the second filter circuit 50, but the present invention is not limited to this, and the frequency passband of the elastic wave filter 1 is not limited to this. May be set to be higher than the frequency passband of the second filter circuit 50.
  • the elastic wave filter 1 is a transmission filter
  • the present invention is not limited to this, and the elastic wave filter 1 may be a reception filter.
  • the multiplexer 5 is not limited to the configuration including both the transmission filter and the reception filter, and may be configured to include only the transmission filter or only the reception filter.
  • a multiplexer including two filters has been described as an example, but in the present invention, for example, a triplexer having common antenna terminals of three filters and a hexaplexer having common antenna terminals of six filters have been described. Can also be applied to. That is, the multiplexer need only have two or more filters.
  • first signal terminal T1 and the second signal terminal T2 may be either an input terminal or an output terminal.
  • first signal terminal T1 when the first signal terminal T1 is an input terminal, the second signal terminal T2 becomes an output terminal, and when the second signal terminal T2 is an input terminal, the first signal terminal T1 becomes an output terminal.
  • the second filter circuit 50 is not limited to the above-mentioned filter configuration, and can be appropriately designed according to the required filter characteristics and the like.
  • the second filter circuit 50 may have a vertically coupled filter structure or a ladder type filter structure.
  • each resonator constituting the second filter circuit 50 is not limited to the SAW resonator, and may be, for example, a BAW (Bulk Acoustic Wave) resonator.
  • the second filter circuit 50 may be configured without using a resonator, and may be, for example, an LC resonance filter or a dielectric filter.
  • the materials constituting the electrode layers 325 and the dielectric layer 326 of the IDT electrodes 31 and 32 and the reflector 40 are not limited to the above-mentioned materials. Further, the IDT electrodes 31 and 32 do not have to have the above-mentioned laminated structure.
  • the IDT electrodes 31 and 32 may be made of, for example, a metal or alloy such as Ti, Al, Cu, Pt, Au, Ag, Pd, or from a plurality of laminates made of the above metal or alloy. It may be configured.
  • a substrate having piezoelectricity is shown as the substrate 320, but the substrate may be a piezoelectric substrate composed of a single layer of a piezoelectric layer.
  • the piezoelectric substrate in this case is composed of, for example, a piezoelectric single crystal of LiTaO 3 or another piezoelectric single crystal such as LiNbO 3.
  • the substrate 320 on which the IDT electrodes 31 and 32 are formed may be entirely composed of a piezoelectric layer or may have a structure in which the piezoelectric layer is laminated on the support substrate, as long as the substrate 320 has piezoelectricity.
  • the cut angle of the substrate 320 according to the above embodiment is not limited.
  • the laminated structure, material, and thickness may be appropriately changed according to the required passing characteristics of the surface acoustic wave filter, and the LiTaO 3 piezoelectric substrate or LiNbO having a cut angle other than the cut angle shown in the above embodiment may be changed. 3 It is possible to obtain the same effect even with an elastic surface wave filter using a piezoelectric substrate or the like.
  • the present invention can be widely used in communication equipment such as mobile phones as a multiplexer having an elastic wave filter, a front-end circuit, and a communication device.
  • Elastic wave filter 5 multiplexer 9 antenna element 10 1st filter circuit 20 additional circuit 21 1st terminal 22 2nd terminal 25, 25A, 25B, 25C, 25D, 25E, 25F, 25G, 25H Elastic wave resonator group 31, 32 , 33 IDT electrodes 31a, 32a, 33a 1st comb tooth electrode 31b, 31c, 31d, 32b, 32c, 32d, 33b 2nd comb tooth electrode 36a, 36b electrode finger 37a, 37b Bus bar electrode 40 reflector 50 second Filter circuit 60 Vertical coupling type elastic wave resonator 320 Substrate 325 Electrode layer 326 Dielectric layer C1, C2 Capacitive element D1 Elastic wave propagation direction D2 Orthogonal direction d1a, d1b, d2a Drawer wiring n0, n1, n2, n3, n4, n5 Nodes P1, P2, P3, P4 Parallel arm resonator r1, r2, r3 Path S1, S2, S3, S4, S

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

Abstract

La présente invention concerne un filtre à ondes élastiques (1) qui comprend un premier circuit de filtre (10) disposé sur un premier trajet (r1) connectant une première borne de signal (T1) et une deuxième borne de signal (T2), et un circuit supplémentaire (20) ayant un groupe de résonateurs à ondes élastiques (25) et connecté à une pluralité de nœuds sur le premier trajet (r1). Le groupe de résonateurs à ondes élastiques (25) comprend une pluralité d'électrodes IDT (31, 32) disposées le long d'une direction de propagation d'ondes élastiques (D1). La pluralité d'électrodes IDT (31, 32) comprennent une pluralité de premières électrodes interdigitées (31a, 32a) et une pluralité de deuxièmes électrodes interdigitées (31b, 32b). La pluralité de premières électrodes interdigitées (31a, 32a) sont électriquement connectées à la pluralité de nœuds. Parmi la pluralité de deuxièmes électrodes interdigitées (31b, 32b), certaines deuxièmes électrodes interdigitées sont connectées à la terre, et d'autres deuxièmes électrodes interdigitées différentes des certaines deuxièmes électrodes interdigitées sont laissées ouvertes sans être connectées à la terre.
PCT/JP2021/024754 2020-07-17 2021-06-30 Filtre à ondes élastiques et multiplexeur WO2022014332A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008283425A (ja) * 2007-05-10 2008-11-20 Tdk Corp 縦結合多重モード共振子型弾性表面波フィルタ
JP2013118611A (ja) * 2011-11-04 2013-06-13 Taiyo Yuden Co Ltd 分波器、フィルタ及び通信モジュール
JP2017092945A (ja) * 2015-10-01 2017-05-25 スカイワークスフィルターソリューションズジャパン株式会社 分波器
WO2020031783A1 (fr) * 2018-08-07 2020-02-13 株式会社村田製作所 Filtre et multiplexeur
US20200144982A1 (en) * 2018-11-05 2020-05-07 Qorvo Us, Inc. Compensation structures for radio frequency filtering devices

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008283425A (ja) * 2007-05-10 2008-11-20 Tdk Corp 縦結合多重モード共振子型弾性表面波フィルタ
JP2013118611A (ja) * 2011-11-04 2013-06-13 Taiyo Yuden Co Ltd 分波器、フィルタ及び通信モジュール
JP2017092945A (ja) * 2015-10-01 2017-05-25 スカイワークスフィルターソリューションズジャパン株式会社 分波器
WO2020031783A1 (fr) * 2018-08-07 2020-02-13 株式会社村田製作所 Filtre et multiplexeur
US20200144982A1 (en) * 2018-11-05 2020-05-07 Qorvo Us, Inc. Compensation structures for radio frequency filtering devices

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