WO2017159834A1 - High-frequency filter element, multiplexer, transmitter, and receiver - Google Patents

High-frequency filter element, multiplexer, transmitter, and receiver Download PDF

Info

Publication number
WO2017159834A1
WO2017159834A1 PCT/JP2017/010814 JP2017010814W WO2017159834A1 WO 2017159834 A1 WO2017159834 A1 WO 2017159834A1 JP 2017010814 W JP2017010814 W JP 2017010814W WO 2017159834 A1 WO2017159834 A1 WO 2017159834A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency
band
transmission
filter
reception
Prior art date
Application number
PCT/JP2017/010814
Other languages
French (fr)
Japanese (ja)
Inventor
正人 荒木
Original Assignee
株式会社村田製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社村田製作所 filed Critical 株式会社村田製作所
Publication of WO2017159834A1 publication Critical patent/WO2017159834A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/38—Impedance-matching networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/46—Networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • 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
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/58—Multiple crystal filters
    • 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
    • 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 a high frequency filter element, a multiplexer, a transmission device, and a reception device.
  • Recent mobile phones are required to support a plurality of frequency bands and a plurality of wireless systems, so-called multiband and multimode, in one terminal.
  • a multiplexer for demultiplexing a high-frequency signal in accordance with a radio carrier frequency (band) is arranged immediately below one antenna.
  • a radio carrier frequency (band) is arranged immediately below one antenna.
  • band pass filters As the plurality of band pass filters constituting the multiplexer, an elastic wave filter characterized by low loss in the pass band and steepness in the vicinity of the pass band is used.
  • Patent Document 1 discloses a duplexer including a reception filter and a transmission filter composed of a ladder-type surface acoustic wave filter. More specifically, the transmission filter has a plurality of parallel arm resonators and a plurality of series arm resonators, and one of the plurality of parallel arm resonators has a higher resonance frequency than the plurality of series arm resonators. In addition, the parallel arm resonator has a lower capacitance than other parallel arm resonators. Thereby, the isolation characteristic in the reception frequency band is improved.
  • the duplexer described in Patent Document 1 can ensure low loss in the pass band, but only by optimizing the resonance frequency and capacitance of the parallel arm resonator, the frequency band of the other party (reception band) It is difficult to ensure a high attenuation throughout.
  • the present invention has been made to solve the above-described problem, and a high-frequency filter element, multiplexer, transmitter, and receiver that can achieve high attenuation outside the passband while ensuring low loss in the passband.
  • the purpose is to provide.
  • a high-frequency filter element includes a first terminal and a second terminal for inputting or outputting a high-frequency signal, and a high frequency in a first frequency band connected to the first terminal.
  • a first filter unit having a characteristic of selectively passing a signal; and a high-frequency signal connected between the second terminal and the first filter unit and having a second frequency band different from the first frequency band is selectively selected.
  • a second filter unit having a characteristic of attenuating the first filter unit, wherein the second filter unit includes a series resonator connected between the first filter unit and the second terminal, and the first filter unit.
  • a parallel resonator connected between a connection path to the second terminal and a reference terminal, and the anti-resonance frequency of the parallel resonator is arranged outside the band of the first frequency band,
  • the resonance frequency of the series resonator is
  • the antiresonance frequency of the series resonator and the resonance frequency of the parallel resonator are between the resonance frequency of the series resonator and the antiresonance frequency of the parallel resonator. It is arranged.
  • the high frequency filter element has a band blocking function for attenuating the high frequency signal in the second frequency band in addition to the first filter unit having a band pass function for allowing the high frequency signal in the first frequency band to pass.
  • a filter unit is provided.
  • the second filter unit has a pair of series resonators and parallel resonators, and from the low frequency side, (1) the resonance frequency of the series resonators, (2) the antiresonance frequency of the series resonators and the parallel resonators. They are arranged in the order of the resonance frequency of the resonator and (3) the anti-resonance frequency of the parallel resonator.
  • the antiresonance frequency of the parallel resonator is arranged outside the band of the first frequency band that is the pass band, the band between the resonance frequency of the series resonator and the antiresonance frequency of the parallel resonator is It is possible to use the second frequency band outside the one frequency band. Therefore, it is possible to achieve high attenuation outside the pass band while ensuring low loss of the pass band by the first filter unit.
  • the anti-resonance frequency of the series resonator and the resonance frequency of the parallel resonator may be arranged in the second frequency band.
  • the high frequency signal in the vicinity of the antiresonance frequency of the series resonator or the resonance frequency of the parallel resonator, which is arranged between the resonance frequency of the series resonator and the antiresonance frequency of the parallel resonator Since the impedance is high in the direction of propagation with the terminal, the passage is blocked. Therefore, it is possible to optimize the attenuation characteristic of the second frequency band that is outside the pass band.
  • an impedance matching circuit connected to the second terminal may be further provided.
  • the second filter unit has a band rejection function, and thus is externally connected to the second terminal. It is assumed that the impedance of the external circuit and the high frequency filter element do not match. On the other hand, by connecting an impedance matching circuit between the second terminal and the second filter unit, impedance matching between the high frequency filter element and the external circuit can be achieved, and a high frequency signal in the first frequency band can be obtained. Can be passed with lower loss.
  • each of the first filter unit and the second filter unit may be formed of an elastic wave resonator using SAW (Surface Acoustic Wave) or BAW (Bulk Acoustic Wave).
  • SAW Surface Acoustic Wave
  • BAW Bulk Acoustic Wave
  • first filter portion and the second filter portion may be formed on a single piezoelectric substrate.
  • first filter unit and the second filter unit may be integrated into one chip.
  • the multiplexer filters the high-frequency signal input from the transmission input terminal and outputs the high-frequency signal in the transmission band to the common terminal; and the input from the common terminal A reception-side filter circuit that filters a high-frequency signal and outputs a high-frequency signal in a reception band to a reception output terminal, wherein the transmission-side filter circuit includes the high-frequency filter element described above, and the transmission band Is the first frequency band, and the reception band is the second frequency band.
  • the multiplexer filters the high-frequency signal input from the transmission input terminal and outputs the high-frequency signal in the transmission band to the common terminal; and the input from the common terminal And a reception-side filter circuit that filters a high-frequency signal and outputs a high-frequency signal in a reception band to a reception output terminal, wherein the reception-side filter circuit includes the high-frequency filter element described above, and the transmission band Is the second frequency band, and the reception band is the first frequency band.
  • the second terminal may be the common terminal, and the impedance matching circuit may be connected between the common terminal and the second filter unit.
  • the impedance of the antenna element connected to the common terminal and the filter circuit may not match.
  • impedance matching between the antenna element and the filter circuit can be achieved by connecting the impedance matching circuit between the common terminal and the second filter unit, and a high-frequency signal in the first frequency band is It is possible to pass through with lower loss.
  • the second terminal may be the transmission input terminal or the reception output terminal, and the impedance matching circuit may be connected between the transmission input terminal or the reception output terminal and the second filter unit. Good.
  • the second filter unit is arranged on the transmission input terminal side or the reception output terminal side of the first filter unit and the second filter unit, an external circuit connected to the transmission input terminal or the reception output terminal And the impedance of the filter circuit are assumed not to match.
  • an impedance matching circuit is connected between the transmission input terminal or the reception output terminal and the second filter unit, so that impedance matching between the external circuit and the filter circuit can be achieved, and the first frequency band It is possible to pass the high-frequency signal with lower loss.
  • the multiplexer is a multiplexer including a first duplexer and a second duplexer, and the first duplexer performs first transmission by filtering a high-frequency signal input from a first transmission input terminal.
  • a first transmission-side filter circuit that outputs a high-frequency signal in a band to an antenna element via a common terminal; and the first transmission band by filtering a high-frequency signal input from the antenna element via the common terminal.
  • a first reception-side filter circuit that outputs a high-frequency signal in a first reception band different from the first reception output terminal to the first reception output terminal, wherein the second duplexer filters the high-frequency signal input from the second transmission input terminal
  • a high-frequency signal in a second transmission band different from the first transmission band and the first reception band is passed through the common terminal.
  • a second transmission-side filter circuit that outputs to the antenna element, and a high-frequency signal input from the antenna element via the common terminal to filter the first transmission band, the first reception band, and the second transmission 7.
  • a second reception side filter circuit that outputs a high-frequency signal in a second reception band different from the band to a second reception output terminal, wherein the first transmission side filter circuit is according to any one of claims 1 to 6.
  • the first transmission band may be the first frequency band
  • the second reception band may be the second frequency band.
  • the second loss is ensured while ensuring low loss in the first transmission band. It is possible to achieve high attenuation of the reception band and high isolation (cross isolation) between the duplexers.
  • the transmission device is a transmission device that transmits high-frequency signals in a plurality of transmission bands via an antenna element, and the transmission device receives a high-frequency signal input from a first transmission input terminal.
  • the first transmission side filter circuit that outputs the high-frequency signal in the first transmission band to the antenna element via the common terminal, and the high-frequency signal input from the second transmission input terminal to filter the first
  • a second transmission-side filter circuit that outputs a high-frequency signal in a second transmission band different from the transmission band to the antenna element via the common terminal, wherein the first transmission-side filter circuit comprises: 6.
  • the high-frequency filter element according to claim 6, wherein the first transmission band is the first frequency band, and the second transmission band is the second frequency band.
  • the first transmission side filter circuit includes the high-frequency filter element
  • the first transmission side filter circuit includes the high-frequency filter element
  • a receiving device is a receiving device that receives high-frequency signals in a plurality of reception bands via an antenna element, and the receiving device receives an input from the antenna element via a common terminal.
  • a first reception-side filter circuit that filters the received high-frequency signal and outputs a high-frequency signal in the first reception band to the first reception output terminal; and a high-frequency signal input from the antenna element via the common terminal
  • a second reception side filter circuit for outputting a high frequency signal in a second reception band different from the first reception band to a second reception output terminal, wherein the first reception side filter circuit comprises: The high frequency filter element according to any one of claims 1 to 4, wherein the first reception band is the first frequency band, and the second reception band is the second frequency band.
  • the first receiving side filter circuit when the first receiving side filter circuit includes the high frequency filter element, the first It is possible to achieve high attenuation in the second reception band and high isolation between the reception side filter circuits while ensuring low loss in the reception band.
  • high attenuation outside the pass band can be achieved while ensuring low loss in the pass band.
  • FIG. 1 is a circuit configuration diagram of a duplexer and peripheral circuits according to an embodiment.
  • FIG. 2 is a circuit configuration diagram of the transmission filter according to the embodiment.
  • FIG. 3 is a plan view and a cross-sectional view schematically showing the resonator of the surface acoustic wave filter according to the embodiment.
  • FIG. 4 is a circuit configuration diagram of a transmission filter according to a comparative example.
  • FIG. 5 is a graph showing the pass characteristic of the duplexer according to the comparative example and the impedance characteristic of each resonator.
  • FIG. 6 is a graph showing pass characteristics of the duplexer according to the embodiment and impedance characteristics of each resonator.
  • FIG. 1 is a circuit configuration diagram of a duplexer and peripheral circuits according to an embodiment.
  • FIG. 2 is a circuit configuration diagram of the transmission filter according to the embodiment.
  • FIG. 3 is a plan view and a cross-sectional view schematically showing the resonator of the surface
  • FIG. 7A is a graph comparing the pass characteristics of the duplexers according to the embodiment and the comparative example.
  • FIG. 7B is a graph comparing the isolation characteristics of the duplexers according to the embodiment and the comparative example.
  • FIG. 8A is a Smith chart of the transmission filter according to the embodiment before the matching circuit is added.
  • FIG. 8B is a Smith chart of the transmission filter according to the embodiment to which a matching circuit is added.
  • FIG. 9 is a circuit configuration diagram of a quadplexer and peripheral circuits according to a modification of the embodiment.
  • FIG. 10 is a circuit configuration diagram of a first transmission-side filter circuit according to a modification of the embodiment.
  • the duplexer 1 is a multiplexer in which a Band 8 transmission side filter circuit and a Band 8 reception side filter circuit are bundled at a common terminal.
  • FIG. 1 is a circuit configuration diagram of a duplexer 1 and peripheral circuits according to the embodiment.
  • the duplexer 1 includes a transmission filter 11, a reception filter 12, a matching circuit 13, a transmission input terminal 10, a reception output terminal 20, and a common terminal 30.
  • the transmission filter 11 and the matching circuit 13 constitute a high frequency filter element.
  • the duplexer 1, the antenna element 2, and the antenna matching circuit 3 constitute a front end circuit.
  • the antenna matching circuit 3 is a circuit that is connected to the antenna element 2 and the duplexer 1 and performs impedance matching between the antenna element 2 and the duplexer 1. As a result, the duplexer 1 can receive the received signal from the antenna element 2 with low loss and output the transmission signal to the antenna element 2 with low loss.
  • the antenna matching circuit 3 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor.
  • the antenna matching circuit 3 is not an essential component of the front end circuit.
  • the transmission filter 11 receives a transmission signal generated by a high-frequency signal processing circuit (RFIC or the like) and amplified via a power amplifier via a transmission input terminal 10, and transmits a Band 8 transmission passband (first frequency). This is a band-pass filter that performs filtering by band) and outputs to the common terminal 30.
  • a matching circuit 13 is connected between the transmission input terminal 10 and the transmission filter 11.
  • the reception filter 12 is a band-pass filter that receives the reception signal input from the common terminal 30, filters the reception signal in the Band 8 reception pass band (second frequency band), and outputs the filtered signal to the reception output terminal 20.
  • the transmission filter 11 and the reception filter 12 are connected to a common terminal 30.
  • the matching circuit 13 is connected to the filter input terminal 14 and the transmission input terminal 10 of the transmission filter 11, and impedance matching is performed for impedance matching between the transmission circuit 11 and an external circuit such as a power amplifier connected to the transmission input terminal 10. Circuit. Thereby, the duplexer 1 can input a transmission signal from an external circuit with low loss.
  • the matching circuit 13 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor, or a wiring pattern formed on a substrate.
  • the matching circuit 13 may be connected between the common terminal 30 and the transmission filter 11.
  • the duplexer 1 having the simplest configuration as the multiplexer according to the present invention is described, but the multiplexer according to the present invention is not limited to the duplexer 1.
  • the multiplexer according to the present invention may be a multiplexer having at least a duplexer 1 configuration, a quadplexer, a pentaplexer, and a multiplexer having a higher number of bands.
  • the FDD (Frequency Division Duplex) system duplexer 1 is described as an example of the multiplexer according to the present invention, but the present invention is also applicable to a TDD (Time Division Duplex) system multiplexer.
  • TDD Time Division Duplex
  • the common terminal is connected to the antenna matching circuit 3
  • the first selection terminal is connected to the transmission filter 11, and the reception filter 12 is connected.
  • An SPDT (Single Pole Double Throw) type switch to which the second selection terminal is connected is arranged. By switching the switch, the transmission filter 11 or the reception filter 12 is exclusively connected to the antenna element 2. Even with this configuration, by having the configuration of the transmission filter 11 according to the present embodiment, it is possible to highly suppress the transmission signal from entering the reception filter 12 via the switch.
  • the transmission filter 11 is composed of a surface acoustic wave (SAW) filter. Thereby, the transmission filter 11 can be downsized.
  • SAW surface acoustic wave
  • FIG. 2 is a circuit configuration diagram of the transmission filter 11 according to the embodiment.
  • the transmission filter 11 has a configuration in which a first filter unit 11A and a second filter unit 11B are connected in cascade.
  • 11 A of 1st filter parts are connected to the common terminal 30 (1st terminal), are provided with the series resonators 101, 102, and 103, and the parallel resonators 151 and 152, and are a high frequency signal of a transmission band (1st frequency band). Is selectively passed.
  • the second filter unit 11B is connected to the transmission input terminal 10 (second terminal) via the filter input terminal 14 and the matching circuit 13, and includes a series resonator 104 and a parallel resonator 153, and a reception band different from the transmission band. It has a characteristic of selectively attenuating a high-frequency signal in the (second frequency band).
  • the series resonators 101 to 104 are connected in series with each other between the filter input terminal 14 and the common terminal 30.
  • the parallel resonators 151 to 153 are connected in parallel to each other between the connection points of the series resonators 101 to 104 and the reference terminal (ground).
  • the first filter unit 11A has a band pass function.
  • the second filter unit 11B has a band rejection function.
  • the transmission filter 11 constitutes a ladder-type bandpass filter as a whole by the cascade connection of the first filter unit 11A and the second filter unit 11B.
  • the first filter portion 11A may not have a configuration of a ladder-type surface acoustic wave element.
  • the circuit configuration of the first filter unit 11A may be, for example, a longitudinally coupled surface acoustic wave element or the like, or elastic using a BAW (Bulk Acoustic Wave), depending on the required specifications of the transmission filter 11. You may be comprised with the wave resonator. Furthermore, it may not have the structure of an acoustic wave element, and may have another filter structure.
  • the circuit configuration of the reception filter 12 is not particularly limited.
  • the reception filter 12 may be, for example, a ladder type surface acoustic wave element, a longitudinally coupled type surface acoustic wave element, or the like according to the required specifications.
  • the transmission filter 11 and the reception filter 12 can be formed on one piezoelectric substrate, and the size can be reduced. Can be realized.
  • the reception filter 12 may be constituted by an acoustic wave resonator using BAW, and may not have the configuration of an acoustic wave element, and may have another filter structure. Also good.
  • FIG. 3 is a plan view and a cross-sectional view schematically showing a resonator of the surface acoustic wave filter according to the embodiment.
  • a schematic plan view and a schematic cross-sectional view showing the structure of the series resonator 101 among the plurality of resonators constituting the transmission filter 11 are illustrated.
  • the series resonator shown in FIG. 3 is for explaining a typical structure of the plurality of resonators, and the number and length of electrode fingers constituting the electrode are limited to this. Not.
  • Each resonator of the transmission filter 11 includes a piezoelectric substrate 510 and comb-shaped IDT (InterDigital Transducer) electrodes 101a and 101b.
  • IDT InterDigital Transducer
  • the IDT electrode 101a includes a plurality of electrode fingers 110a that are parallel to each other and a bus bar electrode 111a that connects the plurality of electrode fingers 110a.
  • the IDT electrode 101b includes a plurality of electrode fingers 110b that are parallel to each other and a bus bar electrode 111b that connects the plurality of electrode fingers 110b.
  • the IDT electrode 54 constituted by the plurality of electrode fingers 110a and 110b and the bus bar electrodes 111a and 111b has a laminated structure of the adhesion layer 541 and the main electrode layer 542 as shown in the sectional view of FIG. ing.
  • the adhesion layer 541 is a layer for improving the adhesion between the piezoelectric substrate 510 and the main electrode layer 542, and, for example, Ti is used as the material.
  • the film thickness of the adhesion layer 541 is, for example, 12 nm.
  • the main electrode layer 542 is made of, for example, Al containing 1% Cu.
  • the film thickness of the main electrode layer 542 is, for example, 162 nm.
  • the protective layer 550 is formed so as to cover the IDT electrodes 101a and 101b.
  • the protective layer 550 is a layer for the purpose of protecting the main electrode layer 542 from the external environment, adjusting frequency temperature characteristics, and improving moisture resistance.
  • the protective layer 550 is a film mainly composed of silicon dioxide. .
  • the materials forming the adhesion layer 541, the main electrode layer 542, and the protective layer 550 are not limited to the materials described above. Furthermore, the IDT electrode 54 does not have to have the above laminated structure.
  • the IDT electrode 54 may be made of, for example, a metal or alloy such as Ti, Al, Cu, Pt, Au, Ag, or Pd, or may be made of a plurality of laminates made of the above metal or alloy. May be. Further, the protective layer 550 may not be formed.
  • the piezoelectric substrate 510 is, for example, a lithium tantalate single crystal or ceramic cut at a predetermined cut angle, and is made of a single crystal or ceramic in which a surface acoustic wave propagates in a predetermined direction.
  • the wavelength of the surface acoustic wave resonator is defined by the repetition pitch ⁇ of the plurality of electrode fingers 110a and 110b constituting the IDT electrodes 101a and 101b shown in the middle of FIG.
  • the crossing width L of the IDT electrode is an electrode finger length where the electrode finger 110a of the IDT electrode 101a and the electrode finger 110b of the IDT electrode 101b overlap as shown in the upper part of FIG.
  • the logarithm is the number of electrode fingers 110a or 110b.
  • each surface acoustic wave filter constituting the transmission filter 11 is not limited to the structure described in FIG.
  • the IDT electrode 54 may not be a laminated structure of metal films but may be a single layer of metal films.
  • both the first filter unit 11A and the second filter unit 11B are formed of surface acoustic wave resonators
  • the first filter unit 11A and the second filter unit 11B are formed of a single piezoelectric substrate 510. It may be formed on the top. This accelerates the downsizing and the low profile of the transmission filter 11 and the duplexer 1.
  • first filter unit 11A and the second filter unit 11B are made into one chip regardless of the circuit configuration of the first filter unit 11A and the second filter unit 11B. Furthermore, the first filter unit 11A, the second filter unit 11B, and the matching circuit 13 may be integrated into one chip. This also promotes downsizing and low profile of the transmission filter 11 and the duplexer 1.
  • the pass characteristics of the duplexer 1 according to the present embodiment will be described in comparison with the pass characteristics of the duplexer according to the comparative example.
  • the circuit configuration and pass characteristic of the transmission filter 411 included in the duplexer according to the comparative example will be described.
  • FIG. 4 is a circuit configuration diagram of the transmission filter 411 according to the comparative example. As illustrated in FIG. 4, the transmission filter 411 includes series resonators 401, 402, 403, and 404 and parallel resonators 451, 452, and 453.
  • the series resonators 401 to 404 are connected in series with each other between the filter input terminal 14 and the common terminal 30.
  • the parallel resonators 451 to 453 are connected in parallel to each other between the connection points of the series resonators 401 to 404 and the reference terminal (ground).
  • the transmission filter 411 constitutes a ladder type band pass filter.
  • FIG. 5 is a graph showing the pass characteristic of the duplexer according to the comparative example and the impedance characteristic of each resonator. More specifically, the upper part of FIG. 5 shows the insertion loss of the duplexer according to the comparative example. The transmission characteristic of the transmission filter 411 between the transmission input terminal 10 and the common terminal 30 and the common terminal 30- The pass characteristics of the reception filter 12 between the reception output terminals 20 are simultaneously shown. The lower part of FIG. 5 shows impedance characteristics of the resonators of the transmission filter 411 included in the duplexer according to the comparative example.
  • the parallel resonators 451 to 453 have a resonance frequency frp and an anti-resonance frequency fap (> frp).
  • Each of the series resonators 401 to 404 has a resonance frequency frs and an anti-resonance frequency fas (> frs> frp).
  • the resonance frequencies of the parallel resonators 451 to 453 do not have to coincide with each other and may vary within a predetermined frequency range.
  • the antiresonance frequencies of the parallel resonators 451 to 453 may not coincide with each other, and may vary within a predetermined frequency range.
  • the resonance frequencies and antiresonance frequencies of the series resonators 401 to 404 do not have to coincide with each other and may vary within a predetermined frequency range.
  • the anti-resonance frequency fap of the parallel resonators 451 to 453 and the resonance frequency frs of the series resonators 401 to 404 are brought close to each other. That is, frp ⁇ frs ⁇ fap ⁇ fas is established.
  • frp ⁇ frs ⁇ fap ⁇ fas is established.
  • the vicinity of the resonance frequency frp where the impedances of the parallel resonators 451 to 453 approach zero becomes a low-frequency side stop band of the transmission band.
  • the impedance of the parallel resonators 451 to 453 increases near the antiresonance frequency fap, and the impedance of the series resonators 401 to 404 approaches 0 near the resonance frequency frs.
  • the signal path from the filter input terminal 14 to the common terminal 30 becomes a signal pass band.
  • the impedance of the series resonators 401 to 404 becomes high, and becomes a high frequency side blocking region of the transmission band.
  • the ladder-type surface acoustic wave filter has a resonance characteristic that is advantageous for ensuring low loss in the pass band and steepness at the low frequency end and high frequency end of the pass band, but outside the pass band. It is difficult to ensure high attenuation outside the passband because the insertion loss rebounds severely. In particular, it is easy to ensure high attenuation at a predetermined frequency point outside the pass band, but for example, it is difficult to ensure high attenuation in the entire reception band when the pass band is the transmission band. . As shown in the upper part of FIG. 5, in the pass characteristic of the transmission filter 411, the attenuation in the reception band cannot be secured.
  • the duplexer 1 according to the present embodiment, it is possible to ensure high attenuation in the reception band while ensuring low loss in the transmission band.
  • FIG. 6 is a graph showing the pass characteristic of the duplexer 1 and the impedance characteristic of each resonator according to the embodiment. More specifically, the upper part of FIG. 6 shows the insertion loss of the duplexer 1 according to the embodiment. The transmission characteristic of the transmission filter 11 between the transmission input terminal 10 and the common terminal 30 and the common terminal The pass characteristic of the reception filter 12 between 30 and the reception output terminal 20 is shown at the same time. 6 shows impedance characteristics of the resonators of the transmission filter 11 included in the duplexer 1 according to the embodiment.
  • the transmission filter 11 is connected to the common terminal 30 and connected to the transmission input terminal 10 via the matching circuit 13 and the first filter unit 11A having a characteristic of selectively allowing a high-frequency signal in the transmission band to pass therethrough. And a second filter unit 11B having a characteristic of selectively attenuating the high frequency signal.
  • the first filter unit 11A is composed of series resonators 101, 102, and 103 and parallel resonators 151 and 152, and has a band-pass function.
  • the parallel resonators 151 to 152 have a resonance frequency frp and an anti-resonance frequency fap (> frp).
  • the series resonators 101 to 103 each have a resonance frequency frs and an anti-resonance frequency fas (> frs> frp). Note that the resonance frequencies of the parallel resonators 151 and 152 do not have to coincide with each other and may vary within a predetermined frequency range. Further, the antiresonance frequencies of the parallel resonators 151 and 152 may not coincide with each other, and may vary within a predetermined frequency range. Further, the resonance frequencies and the anti-resonance frequencies of the series resonators 101 to 103 do not have to coincide with each other and may vary within a predetermined frequency range.
  • the anti-resonance frequency fap of the parallel resonators 151 and 152 and the resonance frequency frs of the series resonators 101 to 103 are brought close to each other. That is, frp ⁇ frs ⁇ fap ⁇ fas is established.
  • frp ⁇ frs ⁇ fap ⁇ fas is established.
  • the vicinity of the resonance frequency frp where the impedance of the parallel resonators 151 and 152 approaches 0 becomes a low-frequency side stop band of the transmission band.
  • the impedances of the parallel resonators 151 and 152 increase near the anti-resonance frequency fap, and the impedances of the series resonators 101 to 103 approach 0 near the resonance frequency frs.
  • the signal path from the transmission input terminal 10 to the common terminal 30 becomes a signal pass band.
  • the impedance of the series resonators 101 to 103 becomes high, which becomes a high-frequency side blocking area of the transmission band.
  • the second filter unit 11B includes a series resonator 104 connected between the first filter unit 11A and the transmission input terminal 10, and a connection path from the first filter unit 11A to the transmission input terminal 10 and the reference terminal. And a parallel resonator 153 connected to each other, and has a band rejection function. More specifically, as shown in the lower part of FIG. 6, the antiresonance frequency fap3 of the parallel resonator 153 is arranged outside the transmission band.
  • the resonance frequency frs4 of the series resonator 104 is lower than the antiresonance frequency fap3 of the parallel resonator 153, and the antiresonance frequency fas4 and parallel resonance of the series resonator 104 are between the resonance frequency frs4 and the antiresonance frequency fap3.
  • the resonance frequency frp3 of the child 153 is arranged. Further, the antiresonance frequency fas4 and the resonance frequency frp3 are substantially the same. That is, frs4 ⁇ fas4 ⁇ frp3 ⁇ fap3 is established in the second filter unit 11B. As a result, as shown in FIG.
  • the vicinity of the resonance frequency frs4 in which the impedance of the series resonator 104 approaches 0 becomes a high-frequency side passband of the transmission band. Further, when the frequency is increased, the impedance of the series resonator 104 increases near the antiresonance frequency fas4, and the impedance of the parallel resonator 153 approaches 0 near the resonance frequency frp3. As a result, in the vicinity of the anti-resonance frequency fas4 to the resonance frequency frp3, a signal blocking region is provided in the signal path from the transmission input terminal 10 to the common terminal 30.
  • the impedance of the parallel resonator 153 becomes high and falls outside the reception band. That is, a high frequency signal between the resonance frequency frs4 of the series resonator 104 and the anti-resonance frequency fap3 of the parallel resonator 153 can be prevented from propagating from the transmission input terminal 10 to the common terminal 30.
  • the anti-resonance frequency fap3 of the parallel resonator 153 is arranged outside the band of the transmission band, a band between the resonance frequency frs4 of the series resonator 104 and the anti-resonance frequency fap3 of the parallel resonator 153 is It is possible to use the reception band outside the transmission band. Therefore, it is possible to achieve high attenuation of the reception band while ensuring low loss of the transmission band by the first filter unit 11A.
  • the antiresonance frequency fas4 of the series resonator 104 and the resonance frequency frp3 of the parallel resonator 153 are preferably arranged in the reception band.
  • the high-frequency signal having the anti-resonance frequency fas4 or the resonance frequency frp3 that has a high impedance in the propagation direction from the transmission input terminal 10 to the common terminal 30 is highly blocked. Therefore, it is possible to optimize the attenuation characteristic of the reception band outside the pass band.
  • the anti-resonance frequency fas4 and the resonance frequency frp3 being arranged in the reception band are not limited to the anti-resonance frequency fas4 and the resonance frequency frp3 being arranged in the reception band.
  • the anti-resonance frequency fas4 and the resonance frequency frp3 may be arranged in a low frequency region or a high frequency region close to the reception band. It is possible to ensure high attenuation over the entire reception band.
  • the antiresonance frequency fas4 of the series resonator 104 and the resonance frequency frp3 of the parallel resonator 153 may be adjusted.
  • the antiresonance frequency fas4 of the series resonator 104 may be shifted to the low frequency side
  • the resonance frequency frp3 of the parallel resonator 153 may be shifted to the high frequency side.
  • FIG. 7A is a graph comparing pass characteristics of the duplexers according to the embodiment and the comparative example.
  • the insertion loss in the pass band of the duplexer 1 according to the present embodiment is substantially equal to the insertion loss in the pass band of the duplexer according to the comparative example.
  • the reception band attenuation characteristic of the transmission filter 11 according to the present embodiment is improved by 10 dB or more compared to the reception band attenuation characteristic of the transmission filter 411 according to the comparative example. I understand.
  • FIG. 7B is a graph comparing the isolation characteristics of the duplexers according to the embodiment and the comparative example. As shown in FIG. 7B, the isolation between the transmission filter 11 and the reception filter 12 of the duplexer 1 according to the present embodiment also includes the transmission filter 411 and the reception filter 12 of the duplexer according to the comparative example. It can be seen that there is an improvement of 10 dB or more compared to the isolation between the two.
  • the transmission filter 11 includes the second filter unit 11B having a band rejection function, so that the impedance between the external circuit connected to the transmission input terminal 10 and the transmission filter 11 is low. Inconsistencies are assumed.
  • the duplexer 1 according to the present embodiment includes a matching circuit 13 connected to the transmission input terminal 10 as a transmission-side filter circuit. Hereinafter, the effect of the matching circuit 13 will be described with reference to FIGS. 8A and 8B.
  • FIG. 8A is a Smith chart of the transmission filter 11 according to the embodiment before the matching circuit 13 is added.
  • the left side of the figure shows the configuration of the front-end circuit including the duplexer 1 according to the present embodiment.
  • the right side of the figure shows the complex when the transmission filter 11 is viewed from the filter input terminal 14.
  • a Smith chart representing impedance is shown.
  • the matching circuit 13 is not disposed between the transmission input terminal 10 and the second filter unit 11B.
  • FIG. 8B is a Smith chart of the transmission filter 11 according to the embodiment to which the matching circuit 13 is added.
  • the left side of the figure shows the configuration of the front end circuit including the duplexer 1 according to the present embodiment, and the right side of the figure shows the complex when the transmission filter 11 is viewed from the transmission input terminal 10.
  • a Smith chart representing impedance is shown.
  • the matching circuit 13 is arranged between the transmission input terminal 10 and the second filter unit 11B.
  • the matching circuit 13 includes, for example, an inductor 131 and a capacitor 132.
  • the inductor 131 is connected to the transmission input terminal 10 and the filter input terminal 14.
  • the capacitor 132 is connected to the transmission input terminal 10 and the reference terminal.
  • the transmission band impedance of the transmission filter 11 in the case where the matching circuit 13 is not added indicates capacitance.
  • an inductor 131 having a predetermined inductance value (15 nH) is connected in series between the second filter unit 11B and the transmission input terminal 10, and a predetermined capacitance value (2.0 pF) is obtained.
  • a capacitor 132 having the same is connected in parallel.
  • the transmission band impedance of the transmission filter 11 is shifted to the characteristic impedance (near the center), so that the insertion loss in the transmission band of the transmission filter 11 is not deteriorated. Furthermore, the impedance of the reception band is higher in FIG. 8B to which the matching circuit 13 is added, so that the attenuation in the reception band can be improved. That is, by connecting the matching circuit 13 between the transmission input terminal 10 and the second filter unit 11B, impedance matching between the transmission filter 11 and the external circuit can be achieved, and a high-frequency signal in the transmission band is It is possible to pass through with lower loss.
  • the matching circuit 13 is added between the second filter unit 11B and the transmission input terminal 10, but the matching circuit 13 is not an essential component.
  • the matching circuit 13 may be appropriately arranged according to the required specifications of the duplexer 1.
  • the second filter unit 11B is disposed between the first filter unit 11A and the filter input terminal 14.
  • the second filter unit 11B includes the common terminal 30 and the first filter unit. It may be arranged between 11A.
  • impedance matching between the antenna element 2 and the transmission filter 11 can be achieved by connecting and arranging the matching circuit 13 between the common terminal 30 and the second filter unit 11B.
  • the high-frequency filter element including the transmission filter 11 and the matching circuit 13 is connected to the common terminal 30 and has a first filter unit 11A having a band-pass function for passing a high-frequency signal in the transmission band.
  • a second filter unit 11B connected between the transmission input terminal 10 and the first filter unit 11A and having a band rejection function for attenuating a high-frequency signal in the reception band.
  • the second filter unit 11B includes a series resonator 104 and a parallel resonator 153, the antiresonance frequency fap3 of the parallel resonator 153 is arranged outside the transmission band, and the resonance frequency frs4 of the series resonator 104 is parallel.
  • the anti-resonance frequency fap3 of the series resonator 104 and the resonance frequency frp3 of the parallel resonator 153 are arranged between the resonance frequency frs4 and the anti-resonance frequency fap3. Further, the high frequency filter element includes a matching circuit 13 connected to the transmission input terminal 10.
  • the quadplexer 4 is a multiplexer in which a Band1 transmission filter circuit and a Band1 reception filter circuit, a Band3 transmission filter circuit, and a Band3 reception filter circuit are bundled at a common terminal. .
  • FIG. 9 is a circuit configuration diagram of the quadplexer 4 and peripheral circuits according to a modification of the embodiment.
  • the quadplexer 4 includes transmission filters 16 (first transmission filter circuit) and 26 (second transmission filter circuit), reception filter 17 (first reception filter circuit), and 27 (second reception side filter circuit), matching circuit 23, transmission input terminal 41 (first transmission input terminal) and 51 (second transmission input terminal), reception output terminal 42 (first reception output terminal), and 52 (second reception output terminal) and a common terminal 30.
  • the transmission filter 16 and the matching circuit 23 constitute a high frequency filter element.
  • the transmission filter 16, the reception filter 17, and the matching circuit 23 constitute a duplexer 1A (first duplexer).
  • the transmission filter 26 and the reception filter 27 constitute a duplexer 1B (second duplexer).
  • the duplexers 1A and 1B, the antenna element 2, and the antenna matching circuit 3 constitute a front end circuit.
  • the antenna matching circuit 3 is connected to the antenna element 2 and the duplexers 1A and 1B, and performs impedance matching between the antenna element 2 and the duplexer 1A, and impedance matching between the antenna element 2 and the duplexer 1B. Thereby, the duplexers 1A and 1B can receive the received signal from the antenna element 2 with low loss and output the transmission signal to the antenna element 2 with low loss.
  • the antenna matching circuit 3 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor.
  • the antenna matching circuit 3 is not an essential component of the front end circuit.
  • the transmission filter 16 inputs a transmission signal generated by a high-frequency signal processing circuit (RFIC or the like) and amplified via a power amplifier via a transmission input terminal 41, and transmits a first transmission band (first) of Band3.
  • This is a band-pass filter that performs filtering in the frequency band and outputs to the common terminal 30.
  • a matching circuit 23 is connected between the transmission input terminal 41 and the transmission filter 16.
  • the reception filter 17 is a band-pass filter that receives the reception signal input from the common terminal 30, filters the first reception band of Band 3, and outputs the filtered signal to the reception output terminal 42.
  • the transmission filter 26 inputs a transmission signal generated by a high-frequency signal processing circuit (RFIC or the like) and amplified via a power amplifier via the transmission input terminal 51, and filters it in the second transmission band of Band1. This is a band-pass filter that outputs to the common terminal 30.
  • RFIC high-frequency signal processing circuit
  • the reception filter 27 is a band-pass filter that receives the reception signal input from the common terminal 30, filters it in the second reception band (second frequency band) of Band 1 and outputs it to the reception output terminal 52.
  • the transmission filters 16 and 26 and the reception filters 17 and 27 are connected to the common terminal 30.
  • the matching circuit 23 is connected to the filter input terminal 24 and the transmission input terminal 41 of the transmission filter 16, and impedance matching is performed for impedance matching between the transmission circuit 16 and an external circuit such as a power amplifier connected to the transmission input terminal 41. Circuit. As a result, the duplexer 1A can input a transmission signal with low loss from an external circuit.
  • the matching circuit 23 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor, or a wiring pattern formed on a substrate. The matching circuit 23 may be connected between the common terminal 30 and the transmission filter 16.
  • the quadplexer 4 is cited as the multiplexer according to the present invention.
  • the multiplexer according to the present invention is not limited to the quadplexer 4, and is a triplexer, a pentaplexer, and the like.
  • the present invention is also applied to a multiplexer having the above number of bands.
  • FIG. 10 is a circuit configuration diagram of the transmission filter 16 according to a modification of the embodiment. As shown in FIG. 10, the transmission filter 16 has a configuration in which a first filter unit 11A, a second filter unit 11B, and a third filter unit 11C are connected in cascade.
  • the first filter unit 11A is connected to the common terminal 30 (first terminal), includes series resonators 101, 102, and 103, and parallel resonators 151 and 152, and has a first transmission band (first frequency band) of Band3. ) To selectively pass high-frequency signals.
  • the third filter unit 11C is disposed between the first filter unit 11A and the filter input terminal 24, includes a series resonator 104 and a parallel resonator 153, and has a first reception band of Band3 different from the first transmission band. It has a characteristic of selectively attenuating a high frequency signal.
  • the second filter unit 11B is disposed between the first filter unit 11A and the filter input terminal 24, is connected to the transmission input terminal 41 (second terminal) via the matching circuit 23, and is in parallel resonance with the series resonator 105. And has a characteristic of selectively attenuating a high-frequency signal in a second reception band (second frequency band) of Band 1 different from the first transmission band and the first reception band.
  • the series resonators 101 to 105 are connected in series with each other between the filter input terminal 24 and the common terminal 30.
  • the parallel resonators 151 to 154 are connected in parallel to each other between the connection points of the series resonators 101 to 105 and the reference terminal (ground).
  • the first filter unit 11A has a band pass function.
  • the third filter unit 11C has a band rejection function of the first reception band of Band3.
  • the second filter unit 11B has a band rejection function of the second reception band of Band1.
  • the transmission filter 16 constitutes a ladder-type bandpass filter as a whole by the cascade connection of the first filter unit 11A, the third filter unit 11C, and the second filter unit 11B.
  • the first filter portion 11A may not have a configuration of a ladder-type surface acoustic wave element.
  • the circuit configuration of the first filter unit 11A may be, for example, a longitudinally coupled surface acoustic wave element or the like according to the required specifications of the transmission filter 16, or configured by an elastic wave resonator using BAW. May be. Furthermore, it may not have the structure of an acoustic wave element, and may have another filter structure.
  • the circuit configurations of the transmission filter 26 and the reception filters 17 and 27 are not particularly limited.
  • the transmission filter 26 and the reception filters 17 and 27 may be, for example, a ladder type surface acoustic wave element, a longitudinally coupled type surface acoustic wave element, or the like according to the required specifications.
  • the transmission filters 11 and 26 and the reception filters 17 and 27 are both composed of surface acoustic wave elements, they can be formed on a single piezoelectric substrate, and downsizing can be realized.
  • the transmission filter 26 and the reception filters 17 and 27 may be constituted by elastic wave resonators using BAW, and may not have an elastic wave element configuration. It may have a filter structure.
  • the third filter unit 11C corresponds to the second filter unit 11B in the duplexer 1 according to the embodiment, and the resonance impedance characteristics of the series resonator 104 and the parallel resonator 153 are the series shown in the lower stage of FIG. Impedance characteristics similar to those of the resonator 104 and the parallel resonator 153 are shown. That is, the antiresonance frequency of the parallel resonator 154 is arranged outside the first transmission band, the resonance frequency of the series resonator 104 is lower than the antiresonance frequency of the parallel resonator 153, and the resonance frequency of the series resonator 104.
  • the antiresonance frequency of the parallel resonator 153, the antiresonance frequency of the series resonator 104 and the resonance frequency of the parallel resonator 153 are arranged. Furthermore, the antiresonance frequency of the series resonator 104 and the resonance frequency of the parallel resonator 153 are arranged in the first reception band of Band3. Accordingly, it is possible to achieve high attenuation of the first reception band of the duplexer 1A while ensuring low loss of the first transmission band in the duplexer 1A. Further, it is possible to improve the isolation (IsoX in FIG. 9) between the transmission filter 16 and the reception filter 17 of the duplexer 1A.
  • the resonance impedance characteristics of the series resonator 105 and the parallel resonator 154 are the same as those of the series resonator 104 and the parallel resonator 153 shown in the lower part of FIG. Indicates. That is, the antiresonance frequency of the parallel resonator 154 is arranged outside the first transmission band, the resonance frequency of the series resonator 105 is lower than the antiresonance frequency of the parallel resonator 154, and the resonance frequency of the series resonator 105.
  • the anti-resonance frequency of the parallel resonator 154, the anti-resonance frequency of the series resonator 105 and the resonance frequency of the parallel resonator 154 are arranged. Furthermore, the antiresonance frequency of the series resonator 105 and the resonance frequency of the parallel resonator 154 are arranged in the second reception band (second frequency band) of Band1. According to this, since the transmission filter 16 of Band3 has the configuration of the second filter unit 11B, the second reception of the duplexer 1A is ensured while ensuring low loss of the first transmission band in the duplexer 1A. It becomes possible to achieve high attenuation of the band. Furthermore, cross-isolation (IsoY in FIG. 9) between the Band3 transmission filter 16 and the Band1 reception filter 27 can be improved.
  • the Band3 transmission filter 16 has a characteristic configuration, that is, a configuration example having the first filter unit 11A, the second filter unit 11B, and the third filter unit 11C.
  • the filter having the configuration may be the reception filters 17 and 27 or the transmission filter 26. Further, the third filter unit 11C may not be provided.
  • the high-frequency filter element and the multiplexer (duplexer) according to the present invention have been described with reference to the above embodiment, but the high-frequency filter element and the multiplexer according to the present invention are not limited to the above-described embodiment.
  • Examples and various devices incorporating the high-frequency filter element of the present disclosure are also included in the present invention.
  • the reception filter 12 may include the second filter unit.
  • the resonance frequency and antiresonance of the series resonator that constitutes the second filter unit when the reception filter 12 has the second filter unit, the resonance frequency and antiresonance of the series resonator that constitutes the second filter unit.
  • the frequency, and the resonance frequency and anti-resonance frequency of the parallel resonator constituting the second filter unit are arranged outside the low frequency band of the transmission band.
  • the high frequency filter element which concerns on this invention is a transmission apparatus which has several transmission bands which bear only transmission, and only reception
  • the present invention is also applied to a receiving apparatus having a plurality of receiving bands for carrying
  • a transmission device that transmits high-frequency signals in a plurality of transmission bands via an antenna element, the transmission device filtering a high-frequency signal input from a first transmission input terminal to generate a high-frequency signal in the first transmission band.
  • a first transmission-side filter circuit that outputs to the antenna element via the common terminal, and a high-frequency signal in a second transmission band different from the first transmission band by filtering the high-frequency signal input from the second transmission input terminal, And a second transmission filter circuit that outputs to the antenna element via the common terminal.
  • the first transmission filter circuit includes the high-frequency filter element according to the above embodiment.
  • the receiving device receives high-frequency signals in a plurality of reception bands via an antenna element, and the receiving device filters high-frequency signals input from the antenna element via a common terminal to obtain a first reception band.
  • a first reception-side filter circuit that outputs a high-frequency signal to the first reception output terminal, and a high-frequency signal in a second reception band different from the first reception band by filtering the high-frequency signal input from the antenna element via the common terminal Is provided to the second reception output terminal.
  • the first reception-side filter circuit includes the high-frequency filter element according to the above embodiment.
  • the duplexer 1 according to the present invention is not limited to the Band8 duplexer as in the above embodiment, and the selection of the band is arbitrary. In the case of a multiplexer, the combination of bands is arbitrary.
  • the piezoelectric substrate 510 constituting the surface acoustic wave filter may have a laminated structure in which a high acoustic velocity support substrate, a low acoustic velocity film, and a piezoelectric film are laminated in this order.
  • the piezoelectric film is made of, for example, LiTaO 3 piezoelectric single crystal or piezoelectric ceramic.
  • the piezoelectric film has a thickness of 600 nm, for example.
  • the high sound velocity support substrate is a substrate that supports the low sound velocity film, the piezoelectric film, and the IDT electrode 54.
  • the high-sonic support substrate is a substrate in which the acoustic velocity of the bulk wave in the high-sonic support substrate is higher than that of the surface wave or boundary wave that propagates through the piezoelectric film. It functions in such a way that it is confined in the portion where the sonic film is laminated and does not leak below the high sonic support substrate.
  • the high sound speed support substrate is, for example, a silicon substrate, and has a thickness of, for example, 200 ⁇ m.
  • the low acoustic velocity film is a membrane in which the acoustic velocity of the bulk wave in the low acoustic velocity film is lower than the bulk wave propagating through the piezoelectric membrane, and is disposed between the piezoelectric membrane and the high acoustic velocity support substrate. Due to this structure and the property that energy is concentrated in a medium where acoustic waves are essentially low in sound velocity, leakage of surface acoustic wave energy to the outside of the IDT electrode is suppressed.
  • the low acoustic velocity film is, for example, a film mainly composed of silicon dioxide and has a thickness of, for example, 670 nm.
  • the Q value at the resonance frequency and the anti-resonance frequency can be significantly increased as compared with a structure in which the piezoelectric substrate 510 is used as a single layer. That is, since a surface acoustic wave resonator having a high Q value can be configured, a filter with a small insertion loss can be configured using the surface acoustic wave resonator.
  • the high sound velocity support substrate has a structure in which a support substrate and a high sound velocity film in which the velocity of the bulk wave propagating is higher than that of the surface wave and boundary wave propagating in the piezoelectric film are stacked. It may be.
  • the support substrate is a piezoelectric material such as sapphire, lithium tantalate, lithium niobate, crystal, alumina, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mullite, steatite, forsterite, etc.
  • Various ceramics, dielectrics such as glass, semiconductors such as silicon and gallium nitride, resin substrates, and the like can be used.
  • the high sound velocity film includes various materials such as aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, DLC film or diamond, a medium mainly composed of the above materials, and a medium mainly composed of a mixture of the above materials. High sound velocity material can be used.
  • the present invention is widely used in communication devices such as mobile phones as high-frequency filters, multiplexers, transmitters, and receivers that have low in-band loss and high out-of-band attenuation that can be applied to multiband and multimode frequency standards. it can.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

A transmission filter (11) is provided with a first filter part (11A) connected to a common terminal (30), the first filter part (11A) causing a high-frequency signal of a transmission band to pass through, and a second filter part (11B) connected between a transmission input terminal (10) and the first filter part (11A), the second filter part (11B) attenuating a high-frequency signal of a reception band. The second filter part (11B) has a series resonator (104) and a parallel resonator (153), the antiresonance frequency (fap3) of the parallel resonator (153) is located outside the transmission band, the resonance frequency (frs4) of the series resonator (104) is lower than the antiresonance frequency (fap3) of the parallel resonator (153), and the antiresonance frequency (fas4) of the series resonator (104) and the resonance frequency (frp3) of the parallel resonator (153) are located between the resonance frequency (frs4) of the series resonator (104) and the antiresonance frequency (fap3) of the parallel resonator (153).

Description

高周波フィルタ素子、マルチプレクサ、送信装置および受信装置High frequency filter element, multiplexer, transmitter, and receiver
　本発明は、高周波フィルタ素子、マルチプレクサ、送信装置および受信装置に関する。 The present invention relates to a high frequency filter element, a multiplexer, a transmission device, and a reception device.
　近年の携帯電話には、一端末で複数の周波数帯域および複数の無線方式、いわゆるマルチバンド化およびマルチモード化に対応することが要求されている。これに対応すべく、１つのアンテナの直下には、無線搬送周波数（バンド）に応じて高周波信号を分波するマルチプレクサが配置される。マルチプレクサを構成する複数の帯域通過フィルタとしては、通過帯域内における低損失性および通過帯域近傍の急峻性を特徴とする弾性波フィルタが用いられる。 Recent mobile phones are required to support a plurality of frequency bands and a plurality of wireless systems, so-called multiband and multimode, in one terminal. In order to cope with this, a multiplexer for demultiplexing a high-frequency signal in accordance with a radio carrier frequency (band) is arranged immediately below one antenna. As the plurality of band pass filters constituting the multiplexer, an elastic wave filter characterized by low loss in the pass band and steepness in the vicinity of the pass band is used.
　特許文献１には、受信フィルタと、ラダー型の弾性表面波フィルタで構成された送信フィルタとを備えたデュプレクサが開示されている。より具体的には、送信フィルタは、複数の並列腕共振子および複数の直列腕共振子を有し、複数の並列腕共振子の１つが複数の直列腕共振子よりも高い共振周波数を有し、かつ、当該並列腕共振子がその他の並列腕共振子よりも低い静電容量を有している。これにより、受信周波数帯域でのアイソレーション特性の改善を図っている。 Patent Document 1 discloses a duplexer including a reception filter and a transmission filter composed of a ladder-type surface acoustic wave filter. More specifically, the transmission filter has a plurality of parallel arm resonators and a plurality of series arm resonators, and one of the plurality of parallel arm resonators has a higher resonance frequency than the plurality of series arm resonators. In addition, the parallel arm resonator has a lower capacitance than other parallel arm resonators. Thereby, the isolation characteristic in the reception frequency band is improved.
国際公開第２０１３／０４６８９２号International Publication No. 2013/046872
　しかしながら、特許文献１に記載されたデュプレクサでは、通過帯域の低損失性を確保できるが、並列腕共振子の共振周波数および静電容量を最適化することのみで、相手方の周波数帯域（受信帯域）全体にわたり高減衰量を確保することは困難である。 However, the duplexer described in Patent Document 1 can ensure low loss in the pass band, but only by optimizing the resonance frequency and capacitance of the parallel arm resonator, the frequency band of the other party (reception band) It is difficult to ensure a high attenuation throughout.
　そこで、本発明は、上記課題を解決するためになされたものであって、通過帯域の低損失性を確保しつつ通過帯域外の高減衰を達成できる高周波フィルタ素子、マルチプレクサ、送信装置および受信装置を提供することを目的とする。 Accordingly, the present invention has been made to solve the above-described problem, and a high-frequency filter element, multiplexer, transmitter, and receiver that can achieve high attenuation outside the passband while ensuring low loss in the passband. The purpose is to provide.
　上記目的を達成するために、本発明の一態様に係る高周波フィルタ素子は、高周波信号を入力または出力する第１端子および第２端子と、前記第１端子に接続され、第１周波数帯域の高周波信号を選択的に通過させる特性を有する第１フィルタ部と、前記第２端子と前記第１フィルタ部との間に接続され、前記第１周波数帯域と異なる第２周波数帯域の高周波信号を選択的に減衰させる特性を有する第２フィルタ部と、を備え、前記第２フィルタ部は、前記第１フィルタ部と前記第２端子との間に接続された直列共振子と、前記第１フィルタ部から前記第２端子までの接続経路と基準端子との間に接続された並列共振子と、を有し、前記並列共振子の反共振周波数は、前記第１周波数帯域の帯域外に配され、前記直列共振子の共振周波数は前記並列共振子の反共振周波数よりも低く、前記直列共振子の共振周波数と前記並列共振子の反共振周波数との間に、前記直列共振子の反共振周波数および前記並列共振子の共振周波数が配されている。 In order to achieve the above object, a high-frequency filter element according to an aspect of the present invention includes a first terminal and a second terminal for inputting or outputting a high-frequency signal, and a high frequency in a first frequency band connected to the first terminal. A first filter unit having a characteristic of selectively passing a signal; and a high-frequency signal connected between the second terminal and the first filter unit and having a second frequency band different from the first frequency band is selectively selected. A second filter unit having a characteristic of attenuating the first filter unit, wherein the second filter unit includes a series resonator connected between the first filter unit and the second terminal, and the first filter unit. A parallel resonator connected between a connection path to the second terminal and a reference terminal, and the anti-resonance frequency of the parallel resonator is arranged outside the band of the first frequency band, The resonance frequency of the series resonator is The antiresonance frequency of the series resonator and the resonance frequency of the parallel resonator are between the resonance frequency of the series resonator and the antiresonance frequency of the parallel resonator. It is arranged.
　上記構成によれば、高周波フィルタ素子は、第１周波数帯域の高周波信号を通過させる帯域通過機能を有する第１フィルタ部のほか、第２周波数帯域の高周波信号を減衰させる帯域阻止機能を有する第２フィルタ部を備える。ここで、第２フィルタ部は、１組の直列共振子および並列共振子を有し、低周波数側から、（１）直列共振子の共振周波数、（２）直列共振子の反共振周波数および並列共振子の共振周波数、（３）並列共振子の反共振周波数、の順で配される。つまり、直列共振子の共振周波数および並列共振子の反共振周波数の間の高周波信号が、第１端子と第２端子との間を伝搬することを排除できる。また、並列共振子の反共振周波数が、通過帯域である第１周波数帯域の帯域外に配されているので、直列共振子の共振周波数および並列共振子の反共振周波数の間の帯域を、第１周波数帯域外の第２周波数帯域に充てることが可能となる。よって、第１フィルタ部による通過帯域の低損失性を確保しつつ、通過帯域外の高減衰を達成することが可能となる。 According to the above configuration, the high frequency filter element has a band blocking function for attenuating the high frequency signal in the second frequency band in addition to the first filter unit having a band pass function for allowing the high frequency signal in the first frequency band to pass. A filter unit is provided. Here, the second filter unit has a pair of series resonators and parallel resonators, and from the low frequency side, (1) the resonance frequency of the series resonators, (2) the antiresonance frequency of the series resonators and the parallel resonators. They are arranged in the order of the resonance frequency of the resonator and (3) the anti-resonance frequency of the parallel resonator. That is, it is possible to exclude the high-frequency signal between the resonance frequency of the series resonator and the anti-resonance frequency of the parallel resonator from propagating between the first terminal and the second terminal. In addition, since the antiresonance frequency of the parallel resonator is arranged outside the band of the first frequency band that is the pass band, the band between the resonance frequency of the series resonator and the antiresonance frequency of the parallel resonator is It is possible to use the second frequency band outside the one frequency band. Therefore, it is possible to achieve high attenuation outside the pass band while ensuring low loss of the pass band by the first filter unit.
　また、前記直列共振子の反共振周波数および前記並列共振子の共振周波数は、前記第２周波数帯域に配されていてもよい。 Further, the anti-resonance frequency of the series resonator and the resonance frequency of the parallel resonator may be arranged in the second frequency band.
　これにより、直列共振子の共振周波数および並列共振子の反共振周波数の間に配される、直列共振子の反共振周波数または並列共振子の共振周波数近傍の高周波信号は、第１端子と第２端子との伝搬方向において高インピーダンスをとるため、通過を阻止される。よって、通過帯域外である第２周波数帯域の減衰特性を最適化することが可能となる。 Thereby, the high frequency signal in the vicinity of the antiresonance frequency of the series resonator or the resonance frequency of the parallel resonator, which is arranged between the resonance frequency of the series resonator and the antiresonance frequency of the parallel resonator, Since the impedance is high in the direction of propagation with the terminal, the passage is blocked. Therefore, it is possible to optimize the attenuation characteristic of the second frequency band that is outside the pass band.
　また、さらに、前記第２端子に接続されたインピーダンス整合回路を備えてもよい。 Furthermore, an impedance matching circuit connected to the second terminal may be further provided.
　第１端子と第２端子との間に第１フィルタ部と第２フィルタ部とが縦続接続された構成において、第２フィルタ部は帯域阻止機能を有することから、第２端子に外部接続された外部回路と高周波フィルタ素子とのインピーダンスが整合しないことが想定される。これに対して、第２端子と第２フィルタ部との間にインピーダンス整合回路が接続されることにより、高周波フィルタ素子と外部回路とのインピーダンス整合をとることができ、第１周波数帯域の高周波信号を、より低損失で通過させることが可能となる。 In the configuration in which the first filter unit and the second filter unit are cascade-connected between the first terminal and the second terminal, the second filter unit has a band rejection function, and thus is externally connected to the second terminal. It is assumed that the impedance of the external circuit and the high frequency filter element do not match. On the other hand, by connecting an impedance matching circuit between the second terminal and the second filter unit, impedance matching between the high frequency filter element and the external circuit can be achieved, and a high frequency signal in the first frequency band can be obtained. Can be passed with lower loss.
　また、前記第１フィルタ部および前記第２フィルタ部のそれぞれは、ＳＡＷ（Ｓｕｒｆａｃｅ　Ａｃｏｕｓｔｉｃ　Ｗａｖｅ）、または、ＢＡＷ（Ｂｕｌｋ　Ａｃｏｕｓｔｉｃ　Ｗａｖｅ）を用いた弾性波共振子で構成されていてもよい。 Further, each of the first filter unit and the second filter unit may be formed of an elastic wave resonator using SAW (Surface Acoustic Wave) or BAW (Bulk Acoustic Wave).
　これにより、高周波フィルタ素子の小型化が可能となる。 This makes it possible to reduce the size of the high-frequency filter element.
　また、前記第１フィルタ部および前記第２フィルタ部は、１枚の圧電基板上に形成されていてもよい。 Further, the first filter portion and the second filter portion may be formed on a single piezoelectric substrate.
　これにより、高周波フィルタ素子の小型化および低背化が加速される。 This accelerates downsizing and height reduction of the high frequency filter element.
　また、前記第１フィルタ部および前記第２フィルタ部は、１チップ化されていてもよい。 Further, the first filter unit and the second filter unit may be integrated into one chip.
　これにより、高周波フィルタ素子の小型化および低背化が促進される。 This promotes downsizing and low profile of the high frequency filter element.
　また、本発明の一態様に係るマルチプレクサは、送信入力端子から入力された高周波信号をフィルタリングして送信帯域の高周波信号を、共通端子に出力する送信側フィルタ回路と、前記共通端子から入力された高周波信号をフィルタリングして受信帯域の高周波信号を受信出力端子に出力する受信側フィルタ回路と、を備えるマルチプレクサであって、前記送信側フィルタ回路は、上記記載の高周波フィルタ素子を含み、前記送信帯域は、前記第１周波数帯域であり、前記受信帯域は、前記第２周波数帯域である。 In addition, the multiplexer according to one aspect of the present invention filters the high-frequency signal input from the transmission input terminal and outputs the high-frequency signal in the transmission band to the common terminal; and the input from the common terminal A reception-side filter circuit that filters a high-frequency signal and outputs a high-frequency signal in a reception band to a reception output terminal, wherein the transmission-side filter circuit includes the high-frequency filter element described above, and the transmission band Is the first frequency band, and the reception band is the second frequency band.
　これにより、送信側フィルタ回路と受信側フィルタ回路とが共通端子で束ねられた構成を有するマルチプレクサにおいて、送信側フィルタ回路に上記高周波フィルタ素子を含む場合には、送信帯域の低損失性を確保しつつ、受信帯域の高減衰および送受信間の高アイソレーションを達成することが可能となる。 As a result, in a multiplexer having a configuration in which the transmission side filter circuit and the reception side filter circuit are bundled at a common terminal, when the transmission side filter circuit includes the high-frequency filter element, a low loss in the transmission band is ensured. However, it is possible to achieve high attenuation of the reception band and high isolation between transmission and reception.
　また、本発明の一態様に係るマルチプレクサは、送信入力端子から入力された高周波信号をフィルタリングして送信帯域の高周波信号を、共通端子に出力する送信側フィルタ回路と、前記共通端子から入力された高周波信号をフィルタリングして受信帯域の高周波信号を受信出力端子に出力する受信側フィルタ回路と、を備えるマルチプレクサであって、前記受信側フィルタ回路は、上記記載の高周波フィルタ素子を含み、前記送信帯域は、前記第２周波数帯域であり、前記受信帯域は、前記第１周波数帯域である。 In addition, the multiplexer according to one aspect of the present invention filters the high-frequency signal input from the transmission input terminal and outputs the high-frequency signal in the transmission band to the common terminal; and the input from the common terminal And a reception-side filter circuit that filters a high-frequency signal and outputs a high-frequency signal in a reception band to a reception output terminal, wherein the reception-side filter circuit includes the high-frequency filter element described above, and the transmission band Is the second frequency band, and the reception band is the first frequency band.
　これにより、送信側フィルタ回路と受信側フィルタ回路とが共通端子で束ねられた構成を有するマルチプレクサにおいて、受信側フィルタ回路に上記高周波フィルタ素子を含む場合には、受信帯域の低損失性を確保しつつ、送信帯域の高減衰および送受信間の高アイソレーションを達成することが可能となる。 As a result, in a multiplexer having a configuration in which the transmission side filter circuit and the reception side filter circuit are bundled at a common terminal, when the reception side filter circuit includes the high frequency filter element, a low loss characteristic of the reception band is ensured. However, it is possible to achieve high attenuation of the transmission band and high isolation between transmission and reception.
　また、前記第２端子は、前記共通端子であり、前記インピーダンス整合回路は、前記共通端子と前記第２フィルタ部との間に接続されていてもよい。 The second terminal may be the common terminal, and the impedance matching circuit may be connected between the common terminal and the second filter unit.
　第１フィルタ部と第２フィルタ部のうち第２フィルタ部のほうが共通端子側に配置されている構成の場合には、共通端子に接続されるアンテナ素子とフィルタ回路とのインピーダンスが整合しないことが想定される。これに対して、共通端子と第２フィルタ部との間にインピーダンス整合回路が接続されることにより、アンテナ素子とフィルタ回路とのインピーダンス整合をとることができ、第１周波数帯域の高周波信号を、より低損失で通過させることが可能となる。 In the configuration in which the second filter unit is arranged on the common terminal side of the first filter unit and the second filter unit, the impedance of the antenna element connected to the common terminal and the filter circuit may not match. is assumed. On the other hand, impedance matching between the antenna element and the filter circuit can be achieved by connecting the impedance matching circuit between the common terminal and the second filter unit, and a high-frequency signal in the first frequency band is It is possible to pass through with lower loss.
　また、前記第２端子は、前記送信入力端子または前記受信出力端子であり、前記インピーダンス整合回路は、前記送信入力端子または前記受信出力端子と前記第２フィルタ部との間に接続されていてもよい。 The second terminal may be the transmission input terminal or the reception output terminal, and the impedance matching circuit may be connected between the transmission input terminal or the reception output terminal and the second filter unit. Good.
　第１フィルタ部と第２フィルタ部のうち第２フィルタ部のほうが送信入力端子側または受信出力端子側に配置されている構成の場合には、送信入力端子または受信出力端子に接続される外部回路とフィルタ回路とのインピーダンスが整合しないことが想定される。これに対して、送信入力端子または受信出力端子と第２フィルタ部との間にインピーダンス整合回路が接続されることにより、外部回路とフィルタ回路とのインピーダンス整合をとることができ、第１周波数帯域の高周波信号を、より低損失で通過させることが可能となる。 In the case where the second filter unit is arranged on the transmission input terminal side or the reception output terminal side of the first filter unit and the second filter unit, an external circuit connected to the transmission input terminal or the reception output terminal And the impedance of the filter circuit are assumed not to match. On the other hand, an impedance matching circuit is connected between the transmission input terminal or the reception output terminal and the second filter unit, so that impedance matching between the external circuit and the filter circuit can be achieved, and the first frequency band It is possible to pass the high-frequency signal with lower loss.
　また、本発明の一態様に係るマルチプレクサは、第１デュプレクサおよび第２デュプレクサを備えるマルチプレクサであって、前記第１デュプレクサは、第１送信入力端子から入力された高周波信号をフィルタリングして第１送信帯域の高周波信号を、共通端子を経由してアンテナ素子に出力する第１送信側フィルタ回路と、前記アンテナ素子から前記共通端子を経由して入力された高周波信号をフィルタリングして前記第１送信帯域と異なる第１受信帯域の高周波信号を第１受信出力端子に出力する第１受信側フィルタ回路と、を備え、前記第２デュプレクサは、第２送信入力端子から入力された高周波信号をフィルタリングして前記第１送信帯域および前記第１受信帯域と異なる第２送信帯域の高周波信号を、前記共通端子を経由して前記アンテナ素子に出力する第２送信側フィルタ回路と、前記アンテナ素子から前記共通端子を経由して入力された高周波信号をフィルタリングして前記第１送信帯域、前記第１受信帯域および前記第２送信帯域と異なる第２受信帯域の高周波信号を第２受信出力端子に出力する第２受信側フィルタ回路と、を備え、前記第１送信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、前記第１送信帯域は、前記第１周波数帯域であり、前記第２受信帯域は、前記第２周波数帯域であってもよい。 The multiplexer according to one aspect of the present invention is a multiplexer including a first duplexer and a second duplexer, and the first duplexer performs first transmission by filtering a high-frequency signal input from a first transmission input terminal. A first transmission-side filter circuit that outputs a high-frequency signal in a band to an antenna element via a common terminal; and the first transmission band by filtering a high-frequency signal input from the antenna element via the common terminal. A first reception-side filter circuit that outputs a high-frequency signal in a first reception band different from the first reception output terminal to the first reception output terminal, wherein the second duplexer filters the high-frequency signal input from the second transmission input terminal A high-frequency signal in a second transmission band different from the first transmission band and the first reception band is passed through the common terminal. A second transmission-side filter circuit that outputs to the antenna element, and a high-frequency signal input from the antenna element via the common terminal to filter the first transmission band, the first reception band, and the second transmission 7. A second reception side filter circuit that outputs a high-frequency signal in a second reception band different from the band to a second reception output terminal, wherein the first transmission side filter circuit is according to any one of claims 1 to 6. The first transmission band may be the first frequency band, and the second reception band may be the second frequency band.
　これにより、複数のデュプレクサが共通端子で束ねられた構成を有するマルチプレクサにおいて、第１送信側フィルタ回路に上記高周波フィルタ素子を含む場合には、第１送信帯域の低損失性を確保しつつ第２受信帯域の高減衰を達成できるとともに、デュプレクサ間の高アイソレーション（クロスアイソレーション）を達成することが可能となる。 Thus, in a multiplexer having a configuration in which a plurality of duplexers are bundled at a common terminal, when the first transmission-side filter circuit includes the high-frequency filter element, the second loss is ensured while ensuring low loss in the first transmission band. It is possible to achieve high attenuation of the reception band and high isolation (cross isolation) between the duplexers.
　また、本発明の一態様に係る送信装置は、アンテナ素子を介して複数の送信帯域の高周波信号を送信する送信装置であって、前記送信装置は、第１送信入力端子から入力された高周波信号をフィルタリングして第１送信帯域の高周波信号を、共通端子を経由してアンテナ素子に出力する第１送信側フィルタ回路と、第２送信入力端子から入力された高周波信号をフィルタリングして前記第１送信帯域と異なる第２送信帯域の高周波信号を、前記共通端子を経由して前記アンテナ素子に出力する第２送信側フィルタ回路と、を備え、前記第１送信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、前記第１送信帯域は、前記第１周波数帯域であり、前記第２送信帯域は、前記第２周波数帯域である。 The transmission device according to one aspect of the present invention is a transmission device that transmits high-frequency signals in a plurality of transmission bands via an antenna element, and the transmission device receives a high-frequency signal input from a first transmission input terminal. The first transmission side filter circuit that outputs the high-frequency signal in the first transmission band to the antenna element via the common terminal, and the high-frequency signal input from the second transmission input terminal to filter the first A second transmission-side filter circuit that outputs a high-frequency signal in a second transmission band different from the transmission band to the antenna element via the common terminal, wherein the first transmission-side filter circuit comprises: 6. The high-frequency filter element according to claim 6, wherein the first transmission band is the first frequency band, and the second transmission band is the second frequency band.
　これにより、第１送信側フィルタ回路と第２送信側フィルタ回路とが共通端子で束ねられた構成を有する送信装置において、第１送信側フィルタ回路に上記高周波フィルタ素子を含む場合には、第１送信帯域の低損失性を確保しつつ、第２送信帯域の高減衰および送信側フィルタ回路間の高アイソレーションを達成することが可能となる。 Thereby, in the transmission device having a configuration in which the first transmission side filter circuit and the second transmission side filter circuit are bundled at the common terminal, when the first transmission side filter circuit includes the high-frequency filter element, the first It is possible to achieve high attenuation of the second transmission band and high isolation between the transmission side filter circuits while ensuring low loss of the transmission band.
　また、本発明の一態様に係る受信装置は、アンテナ素子を介して複数の受信帯域の高周波信号を受信する受信装置であって、前記受信装置は、前記アンテナ素子から共通端子を経由して入力された高周波信号をフィルタリングして第１受信帯域の高周波信号を第１受信出力端子に出力する第１受信側フィルタ回路と、前記アンテナ素子から前記共通端子を経由して入力された高周波信号をフィルタリングして第１受信帯域と異なる第２受信帯域の高周波信号を第２受信出力端子に出力する第２受信側フィルタ回路と、を備え、前記第１受信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、前記第１受信帯域は、前記第１周波数帯域であり、前記第２受信帯域は、前記第２周波数帯域である。 A receiving device according to one embodiment of the present invention is a receiving device that receives high-frequency signals in a plurality of reception bands via an antenna element, and the receiving device receives an input from the antenna element via a common terminal. A first reception-side filter circuit that filters the received high-frequency signal and outputs a high-frequency signal in the first reception band to the first reception output terminal; and a high-frequency signal input from the antenna element via the common terminal And a second reception side filter circuit for outputting a high frequency signal in a second reception band different from the first reception band to a second reception output terminal, wherein the first reception side filter circuit comprises: The high frequency filter element according to any one of claims 1 to 4, wherein the first reception band is the first frequency band, and the second reception band is the second frequency band.
　これにより、第１受信側フィルタ回路と第２受信側フィルタ回路とが共通端子で束ねられた構成を有する受信装置において、第１受信側フィルタ回路に上記高周波フィルタ素子を含む場合には、第１受信帯域の低損失性を確保しつつ、第２受信帯域の高減衰および受信側フィルタ回路間の高アイソレーションを達成することが可能となる。 Thus, in a receiving apparatus having a configuration in which the first receiving side filter circuit and the second receiving side filter circuit are bundled at a common terminal, when the first receiving side filter circuit includes the high frequency filter element, the first It is possible to achieve high attenuation in the second reception band and high isolation between the reception side filter circuits while ensuring low loss in the reception band.
　本発明に係る高周波フィルタ素子、マルチプレクサ、送信装置または受信装置によれば、通過帯域の低損失性を確保しつつ通過帯域外の高減衰を達成できる。 According to the high-frequency filter element, the multiplexer, the transmission device, or the reception device according to the present invention, high attenuation outside the pass band can be achieved while ensuring low loss in the pass band.
図１は、実施の形態に係るデュプレクサおよび周辺回路の回路構成図である。FIG. 1 is a circuit configuration diagram of a duplexer and peripheral circuits according to an embodiment. 図２は、実施の形態に係る送信用フィルタの回路構成図である。FIG. 2 is a circuit configuration diagram of the transmission filter according to the embodiment. 図３は、実施の形態に係る弾性表面波フィルタの共振子を模式的に表す平面図および断面図である。FIG. 3 is a plan view and a cross-sectional view schematically showing the resonator of the surface acoustic wave filter according to the embodiment. 図４は、比較例に係る送信用フィルタの回路構成図である。FIG. 4 is a circuit configuration diagram of a transmission filter according to a comparative example. 図５は、比較例に係るデュプレクサの通過特性および各共振子のインピーダンス特性を表すグラフである。FIG. 5 is a graph showing the pass characteristic of the duplexer according to the comparative example and the impedance characteristic of each resonator. 図６は、実施の形態に係るデュプレクサの通過特性および各共振子のインピーダンス特性を表すグラフである。FIG. 6 is a graph showing pass characteristics of the duplexer according to the embodiment and impedance characteristics of each resonator. 図７Ａは、実施の形態および比較例に係るデュプレクサの通過特性を比較したグラフである。FIG. 7A is a graph comparing the pass characteristics of the duplexers according to the embodiment and the comparative example. 図７Ｂは、実施の形態および比較例に係るデュプレクサのアイソレーション特性を比較したグラフである。FIG. 7B is a graph comparing the isolation characteristics of the duplexers according to the embodiment and the comparative example. 図８Ａは、整合回路が付加される前の、実施の形態に係る送信用フィルタのスミスチャートである。FIG. 8A is a Smith chart of the transmission filter according to the embodiment before the matching circuit is added. 図８Ｂは、整合回路が付加された、実施の形態に係る送信用フィルタのスミスチャートである。FIG. 8B is a Smith chart of the transmission filter according to the embodiment to which a matching circuit is added. 図９は、実施の形態の変形例に係るクワッドプレクサおよび周辺回路の回路構成図である。FIG. 9 is a circuit configuration diagram of a quadplexer and peripheral circuits according to a modification of the embodiment. 図１０は、実施の形態の変形例に係る第１送信側フィルタ回路の回路構成図である。FIG. 10 is a circuit configuration diagram of a first transmission-side filter circuit according to a modification of the embodiment.
　以下、本発明の実施の形態について、図面を用いて詳細に説明する。なお、以下で説明する実施の形態は、いずれも包括的または具体的な例を示すものである。以下の実施の形態で示される数値、形状、材料、構成要素、構成要素の配置および接続形態などは、一例であり、本発明を限定する主旨ではない。以下の実施の形態における構成要素のうち、独立請求項に記載されていない構成要素については、任意の構成要素として説明される。また、図面に示される構成要素の大きさまたは大きさの比は、必ずしも厳密ではない。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement of constituent elements, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Among the constituent elements in the following embodiments, constituent elements not described in the independent claims are described as optional constituent elements. In addition, the size or size ratio of the components shown in the drawings is not necessarily strict.
　［１．マルチプレクサの基本構成］
　本実施の形態では、ＬＴＥ（Ｌｏｎｇ　Ｔｅｒｍ　Ｅｖｏｌｕｔｉｏｎ）規格のＢａｎｄ８（送信通過帯域：８８０－９１５ＭＨｚ、受信通過帯域：９２５－９６０ＭＨｚ）に適用されるデュプレクサについて例示する。 [1. Basic configuration of multiplexer]
In the present embodiment, a duplexer applied to Band 8 (transmission passband: 880-915 MHz, reception passband: 925-960 MHz) of LTE (Long Term Evolution) standard will be exemplified.
　本実施の形態に係るデュプレクサ１は、Ｂａｎｄ８の送信側フィルタ回路とＢａｎｄ８の受信側フィルタ回路とが共通端子で束ねられたマルチプレクサである。 The duplexer 1 according to the present embodiment is a multiplexer in which a Band 8 transmission side filter circuit and a Band 8 reception side filter circuit are bundled at a common terminal.
　図１は、実施の形態に係るデュプレクサ１および周辺回路の回路構成図である。同図に示すように、デュプレクサ１は、送信用フィルタ１１と、受信用フィルタ１２と、整合回路１３と、送信入力端子１０と、受信出力端子２０と、共通端子３０とを備える。送信用フィルタ１１と整合回路１３とは、高周波フィルタ素子を構成している。なお、デュプレクサ１、アンテナ素子２、およびアンテナ整合回路３は、フロントエンド回路を構成している。 FIG. 1 is a circuit configuration diagram of a duplexer 1 and peripheral circuits according to the embodiment. As shown in the figure, the duplexer 1 includes a transmission filter 11, a reception filter 12, a matching circuit 13, a transmission input terminal 10, a reception output terminal 20, and a common terminal 30. The transmission filter 11 and the matching circuit 13 constitute a high frequency filter element. The duplexer 1, the antenna element 2, and the antenna matching circuit 3 constitute a front end circuit.
　アンテナ整合回路３は、アンテナ素子２およびデュプレクサ１に接続され、アンテナ素子２とデュプレクサ１とのインピーダンス整合をとる回路である。これにより、デュプレクサ１は、アンテナ素子２から低損失で受信信号を受信し、送信信号を低損失でアンテナ素子２へ出力することが可能となる。アンテナ整合回路３は、１以上の高周波回路部品で構成されており、例えば、チップ状のインダクタおよびチップ状のコンデンサからなる。なお、アンテナ整合回路３は、フロントエンド回路の必須構成要素ではない。 The antenna matching circuit 3 is a circuit that is connected to the antenna element 2 and the duplexer 1 and performs impedance matching between the antenna element 2 and the duplexer 1. As a result, the duplexer 1 can receive the received signal from the antenna element 2 with low loss and output the transmission signal to the antenna element 2 with low loss. The antenna matching circuit 3 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor. The antenna matching circuit 3 is not an essential component of the front end circuit.
　送信用フィルタ１１は、高周波信号処理回路（ＲＦＩＣなど）で生成されパワーアンプを経由して増幅された送信信号を、送信入力端子１０を経由して入力し、Ｂａｎｄ８の送信通過帯域（第１周波数帯域）でフィルタリングして共通端子３０へ出力する帯域通過フィルタである。また、送信入力端子１０と送信用フィルタ１１との間には、整合回路１３が接続されている。 The transmission filter 11 receives a transmission signal generated by a high-frequency signal processing circuit (RFIC or the like) and amplified via a power amplifier via a transmission input terminal 10, and transmits a Band 8 transmission passband (first frequency). This is a band-pass filter that performs filtering by band) and outputs to the common terminal 30. A matching circuit 13 is connected between the transmission input terminal 10 and the transmission filter 11.
　受信用フィルタ１２は、共通端子３０から入力された受信信号を入力し、Ｂａｎｄ８の受信通過帯域（第２周波数帯域）でフィルタリングして受信出力端子２０へ出力する帯域通過フィルタである。 The reception filter 12 is a band-pass filter that receives the reception signal input from the common terminal 30, filters the reception signal in the Band 8 reception pass band (second frequency band), and outputs the filtered signal to the reception output terminal 20.
　送信用フィルタ１１および受信用フィルタ１２は、共通端子３０に接続されている。 The transmission filter 11 and the reception filter 12 are connected to a common terminal 30.
　整合回路１３は、送信用フィルタ１１のフィルタ入力端子１４および送信入力端子１０に接続され、送信入力端子１０に接続されるパワーアンプなどの外部回路と送信用フィルタ１１とのインピーダンス整合をとるインピーダンス整合回路である。これにより、デュプレクサ１は、外部回路から低損失で送信信号を入力することが可能となる。整合回路１３は、１以上の高周波回路部品で構成されており、例えば、チップ状のインダクタおよびチップ状のコンデンサ、または、基板上に形成された配線パターンからなる。なお、整合回路１３は、共通端子３０と送信用フィルタ１１との間に接続されていてもよい。 The matching circuit 13 is connected to the filter input terminal 14 and the transmission input terminal 10 of the transmission filter 11, and impedance matching is performed for impedance matching between the transmission circuit 11 and an external circuit such as a power amplifier connected to the transmission input terminal 10. Circuit. Thereby, the duplexer 1 can input a transmission signal from an external circuit with low loss. The matching circuit 13 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor, or a wiring pattern formed on a substrate. The matching circuit 13 may be connected between the common terminal 30 and the transmission filter 11.
　なお、本実施の形態では、本発明に係るマルチプレクサとして最も簡素な構成を有するデュプレクサ１を挙げているが、本発明に係るマルチプレクサは、デュプレクサ１に限定されない。本発明に係るマルチプレクサは、少なくともデュプレクサ１の構成を有するトリプレクサ、クワッドプレクサ、ペンタプレクサ、およびそれ以上のバンド数を有するマルチプレクサであればよい。 In the present embodiment, the duplexer 1 having the simplest configuration as the multiplexer according to the present invention is described, but the multiplexer according to the present invention is not limited to the duplexer 1. The multiplexer according to the present invention may be a multiplexer having at least a duplexer 1 configuration, a quadplexer, a pentaplexer, and a multiplexer having a higher number of bands.
　また、本実施の形態では、本発明に係るマルチプレクサの一例として、ＦＤＤ（Ｆｒｅｑｕｅｎｃｙ　Ｄｉｖｉｓｉｏｎ　Ｄｕｐｌｅｘ）方式のデュプレクサ１を挙げたが、ＴＤＤ（Ｔｉｍｅ　Ｄｉｖｉｓｉｏｎ　Ｄｕｐｌｅｘ）方式のマルチプレクサにも適用可能である。この場合、例えば、共通端子、第１選択端子および第２選択端子を有し、アンテナ整合回路３に共通端子が接続され、送信用フィルタ１１に第１選択端子が接続され、受信用フィルタ１２に第２選択端子が接続されたＳＰＤＴ（Ｓｉｎｇｌｅ　Ｐｏｌｅ　Ｄｏｕｂｌｅ　Ｔｈｒｏｗ）型のスイッチが配置される。このスイッチの切り替えにより、送信用フィルタ１１または受信用フィルタ１２がアンテナ素子２と排他的に接続される。この構成であっても、本実施の形態に係る送信用フィルタ１１の構成を有することにより、送信信号がスイッチを介して受信用フィルタ１２へ回り込むことを高度に抑制できるという効果が奏される。 In this embodiment, the FDD (Frequency Division Duplex) system duplexer 1 is described as an example of the multiplexer according to the present invention, but the present invention is also applicable to a TDD (Time Division Duplex) system multiplexer. In this case, for example, it has a common terminal, a first selection terminal, and a second selection terminal, the common terminal is connected to the antenna matching circuit 3, the first selection terminal is connected to the transmission filter 11, and the reception filter 12 is connected. An SPDT (Single Pole Double Throw) type switch to which the second selection terminal is connected is arranged. By switching the switch, the transmission filter 11 or the reception filter 12 is exclusively connected to the antenna element 2. Even with this configuration, by having the configuration of the transmission filter 11 according to the present embodiment, it is possible to highly suppress the transmission signal from entering the reception filter 12 via the switch.
　本実施の形態に係るデュプレクサ１では、送信用フィルタ１１は、弾性表面波（ＳＡＷ）フィルタで構成されている。これにより、送信用フィルタ１１の小型化が可能となる。以下では、送信用フィルタの回路構成について説明する。 In the duplexer 1 according to the present embodiment, the transmission filter 11 is composed of a surface acoustic wave (SAW) filter. Thereby, the transmission filter 11 can be downsized. Hereinafter, the circuit configuration of the transmission filter will be described.
　［２．送信用フィルタの回路構成］
　図２は、実施の形態に係る送信用フィルタ１１の回路構成図である。図２に示すように、送信用フィルタ１１は、第１フィルタ部１１Ａと第２フィルタ部１１Ｂとが縦続接続された構成を有する。第１フィルタ部１１Ａは、共通端子３０（第１端子）に接続され、直列共振子１０１、１０２および１０３と、並列共振子１５１および１５２とを備え、送信帯域（第１周波数帯域）の高周波信号を選択的に通過させる特性を有する。第２フィルタ部１１Ｂは、フィルタ入力端子１４および整合回路１３を介して送信入力端子１０（第２端子）に接続され、直列共振子１０４と並列共振子１５３とを備え、送信帯域と異なる受信帯域（第２周波数帯域）の高周波信号を選択的に減衰させる特性を有する。 [2. Circuit configuration of transmission filter]
FIG. 2 is a circuit configuration diagram of the transmission filter 11 according to the embodiment. As shown in FIG. 2, the transmission filter 11 has a configuration in which a first filter unit 11A and a second filter unit 11B are connected in cascade. 11 A of 1st filter parts are connected to the common terminal 30 (1st terminal), are provided with the series resonators 101, 102, and 103, and the parallel resonators 151 and 152, and are a high frequency signal of a transmission band (1st frequency band). Is selectively passed. The second filter unit 11B is connected to the transmission input terminal 10 (second terminal) via the filter input terminal 14 and the matching circuit 13, and includes a series resonator 104 and a parallel resonator 153, and a reception band different from the transmission band. It has a characteristic of selectively attenuating a high-frequency signal in the (second frequency band).
　直列共振子１０１～１０４は、フィルタ入力端子１４と共通端子３０との間に互いに直列に接続されている。また、並列共振子１５１～１５３は、直列共振子１０１～１０４の各接続点と基準端子（グランド）との間に互いに並列に接続されている。直列共振子１０１～１０３および並列共振子１５１～１５２の上記接続構成により、第１フィルタ部１１Ａは、帯域通過機能を有する。また、直列共振子１０４および並列共振子１５３の上記接続構成により、第２フィルタ部１１Ｂは、帯域阻止機能を有する。送信用フィルタ１１は、第１フィルタ部１１Ａと第２フィルタ部１１Ｂとの縦続接続により、全体として、ラダー型のバンドパスフィルタを構成している。 The series resonators 101 to 104 are connected in series with each other between the filter input terminal 14 and the common terminal 30. The parallel resonators 151 to 153 are connected in parallel to each other between the connection points of the series resonators 101 to 104 and the reference terminal (ground). With the connection configuration of the series resonators 101 to 103 and the parallel resonators 151 to 152, the first filter unit 11A has a band pass function. Further, due to the connection configuration of the series resonator 104 and the parallel resonator 153, the second filter unit 11B has a band rejection function. The transmission filter 11 constitutes a ladder-type bandpass filter as a whole by the cascade connection of the first filter unit 11A and the second filter unit 11B.
　なお、第１フィルタ部１１Ａは、ラダー型の弾性表面波素子の構成を有していなくてもよい。第１フィルタ部１１Ａの回路構成は、送信用フィルタ１１の要求仕様に応じて、例えば、縦結合型の弾性表面波素子などであってもよく、または、ＢＡＷ（Ｂｕｌｋ　Ａｃｏｕｓｔｉｃ　Ｗａｖｅ）を用いた弾性波共振子で構成されていてもよい。さらには、弾性波素子の構成を有していなくてもよく、その他のフィルタ構造を有していてもよい。 Note that the first filter portion 11A may not have a configuration of a ladder-type surface acoustic wave element. The circuit configuration of the first filter unit 11A may be, for example, a longitudinally coupled surface acoustic wave element or the like, or elastic using a BAW (Bulk Acoustic Wave), depending on the required specifications of the transmission filter 11. You may be comprised with the wave resonator. Furthermore, it may not have the structure of an acoustic wave element, and may have another filter structure.
　また、本実施の形態に係るデュプレクサ１では、受信用フィルタ１２の回路構成は、特に限定されない。受信用フィルタ１２は、その要求仕様に応じて、例えば、ラダー型の弾性表面波素子、縦結合型の弾性表面波素子などであってもよい。送信用フィルタ１１および受信用フィルタ１２がともに弾性表面波素子で構成される場合には、送信用フィルタ１１および受信用フィルタ１２を、１枚の圧電基板上に形成することが可能となり、小型化が実現できる。また、受信用フィルタ１２は、ＢＡＷを用いた弾性波共振子で構成されていてもよく、さらには、弾性波素子の構成を有していなくてもよく、その他のフィルタ構造を有していてもよい。 Moreover, in the duplexer 1 according to the present embodiment, the circuit configuration of the reception filter 12 is not particularly limited. The reception filter 12 may be, for example, a ladder type surface acoustic wave element, a longitudinally coupled type surface acoustic wave element, or the like according to the required specifications. When both the transmission filter 11 and the reception filter 12 are composed of surface acoustic wave elements, the transmission filter 11 and the reception filter 12 can be formed on one piezoelectric substrate, and the size can be reduced. Can be realized. Further, the reception filter 12 may be constituted by an acoustic wave resonator using BAW, and may not have the configuration of an acoustic wave element, and may have another filter structure. Also good.
　［３．弾性表面波共振子の構造］
　ここで、送信用フィルタ１１を構成する弾性表面波共振子の構造について説明する。 [3. Structure of surface acoustic wave resonator]
Here, the structure of the surface acoustic wave resonator constituting the transmission filter 11 will be described.
　図３は、実施の形態に係る弾性表面波フィルタの共振子を模式的に表す平面図および断面図である。同図には、送信用フィルタ１１を構成する複数の共振子のうち、直列共振子１０１の構造を表す平面摸式図および断面模式図が例示されている。なお、図３に示された直列共振子は、上記複数の共振子の典型的な構造を説明するためのものであって、電極を構成する電極指の本数や長さなどは、これに限定されない。 FIG. 3 is a plan view and a cross-sectional view schematically showing a resonator of the surface acoustic wave filter according to the embodiment. In the figure, a schematic plan view and a schematic cross-sectional view showing the structure of the series resonator 101 among the plurality of resonators constituting the transmission filter 11 are illustrated. Note that the series resonator shown in FIG. 3 is for explaining a typical structure of the plurality of resonators, and the number and length of electrode fingers constituting the electrode are limited to this. Not.
　送信用フィルタ１１の各共振子は、圧電基板５１０と、櫛形形状を有するＩＤＴ（ＩｎｔｅｒＤｉｇｉｔａｌ　Ｔｒａｎｓｄｕｃｅｒ）電極１０１ａおよび１０１ｂとで構成されている。 Each resonator of the transmission filter 11 includes a piezoelectric substrate 510 and comb-shaped IDT (InterDigital Transducer) electrodes 101a and 101b.
　図３の平面図に示すように、圧電基板５１０の上には、互いに対向する一対のＩＤＴ電極１０１ａおよび１０１ｂが形成されている。ＩＤＴ電極１０１ａは、互いに平行な複数の電極指１１０ａと、複数の電極指１１０ａを接続するバスバー電極１１１ａとで構成されている。また、ＩＤＴ電極１０１ｂは、互いに平行な複数の電極指１１０ｂと、複数の電極指１１０ｂを接続するバスバー電極１１１ｂとで構成されている。 As shown in the plan view of FIG. 3, a pair of IDT electrodes 101a and 101b facing each other are formed on the piezoelectric substrate 510. The IDT electrode 101a includes a plurality of electrode fingers 110a that are parallel to each other and a bus bar electrode 111a that connects the plurality of electrode fingers 110a. The IDT electrode 101b includes a plurality of electrode fingers 110b that are parallel to each other and a bus bar electrode 111b that connects the plurality of electrode fingers 110b.
　また、複数の電極指１１０ａおよび１１０ｂ、ならびに、バスバー電極１１１ａおよび１１１ｂで構成されるＩＤＴ電極５４は、図３の断面図に示すように、密着層５４１と主電極層５４２との積層構造となっている。 Further, the IDT electrode 54 constituted by the plurality of electrode fingers 110a and 110b and the bus bar electrodes 111a and 111b has a laminated structure of the adhesion layer 541 and the main electrode layer 542 as shown in the sectional view of FIG. ing.
　密着層５４１は、圧電基板５１０と主電極層５４２との密着性を向上させるための層であり、材料として、例えば、Ｔｉが用いられる。密着層５４１の膜厚は、例えば、１２ｎｍである。 The adhesion layer 541 is a layer for improving the adhesion between the piezoelectric substrate 510 and the main electrode layer 542, and, for example, Ti is used as the material. The film thickness of the adhesion layer 541 is, for example, 12 nm.
　主電極層５４２は、材料として、例えば、Ｃｕを１％含有したＡｌが用いられる。主電極層５４２の膜厚は、例えば１６２ｎｍである。 The main electrode layer 542 is made of, for example, Al containing 1% Cu. The film thickness of the main electrode layer 542 is, for example, 162 nm.
　保護層５５０は、ＩＤＴ電極１０１ａおよび１０１ｂを覆うように形成されている。保護層５５０は、主電極層５４２を外部環境から保護する、周波数温度特性を調整する、および、耐湿性を高めるなどを目的とする層であり、例えば、二酸化ケイ素を主成分とする膜である。 The protective layer 550 is formed so as to cover the IDT electrodes 101a and 101b. The protective layer 550 is a layer for the purpose of protecting the main electrode layer 542 from the external environment, adjusting frequency temperature characteristics, and improving moisture resistance. For example, the protective layer 550 is a film mainly composed of silicon dioxide. .
　なお、密着層５４１、主電極層５４２および保護層５５０を構成する材料は、上述した材料に限定されない。さらに、ＩＤＴ電極５４は、上記積層構造でなくてもよい。ＩＤＴ電極５４は、例えば、Ｔｉ、Ａｌ、Ｃｕ、Ｐｔ、Ａｕ、Ａｇ、Ｐｄなどの金属又は合金から構成されてもよく、また、上記の金属又は合金から構成される複数の積層体から構成されてもよい。また、保護層５５０は、形成されていなくてもよい。 Note that the materials forming the adhesion layer 541, the main electrode layer 542, and the protective layer 550 are not limited to the materials described above. Furthermore, the IDT electrode 54 does not have to have the above laminated structure. The IDT electrode 54 may be made of, for example, a metal or alloy such as Ti, Al, Cu, Pt, Au, Ag, or Pd, or may be made of a plurality of laminates made of the above metal or alloy. May be. Further, the protective layer 550 may not be formed.
　圧電基板５１０は、例えば、所定のカット角で切断されたタンタル酸リチウム単結晶、またはセラミックスであって、所定の方向に弾性表面波が伝搬する単結晶またはセラミックスからなる。 The piezoelectric substrate 510 is, for example, a lithium tantalate single crystal or ceramic cut at a predetermined cut angle, and is made of a single crystal or ceramic in which a surface acoustic wave propagates in a predetermined direction.
　ここで、ＩＤＴ電極の設計パラメータについて説明する。弾性表面波共振子の波長とは、図３の中段に示すＩＤＴ電極１０１ａおよび１０１ｂを構成する複数の電極指１１０ａおよび１１０ｂの繰り返しピッチλで規定される。また、ＩＤＴ電極の交叉幅Ｌは、図３の上段に示すように、ＩＤＴ電極１０１ａの電極指１１０ａとＩＤＴ電極１０１ｂの電極指１１０ｂとが重複する電極指長さである。また、対数は、複数の電極指１１０ａまたは１１０ｂの本数である。 Here, IDT electrode design parameters will be described. The wavelength of the surface acoustic wave resonator is defined by the repetition pitch λ of the plurality of electrode fingers 110a and 110b constituting the IDT electrodes 101a and 101b shown in the middle of FIG. Further, the crossing width L of the IDT electrode is an electrode finger length where the electrode finger 110a of the IDT electrode 101a and the electrode finger 110b of the IDT electrode 101b overlap as shown in the upper part of FIG. The logarithm is the number of electrode fingers 110a or 110b.
　なお、本実施の形態に係る送信用フィルタ１１を構成する各弾性表面波フィルタの構造は、図３に記載された構造に限定されない。例えば、ＩＤＴ電極５４は、金属膜の積層構造でなく、金属膜の単層であってもよい。 It should be noted that the structure of each surface acoustic wave filter constituting the transmission filter 11 according to the present embodiment is not limited to the structure described in FIG. For example, the IDT electrode 54 may not be a laminated structure of metal films but may be a single layer of metal films.
　なお、第１フィルタ部１１Ａおよび第２フィルタ部１１Ｂが、ともに、弾性表面波共振子で構成されている場合には、第１フィルタ部１１Ａおよび第２フィルタ部１１Ｂは、１枚の圧電基板５１０上に形成されていてもよい。これにより、送信用フィルタ１１およびデュプレクサ１の小型化および低背化が加速される。 In addition, when both the first filter unit 11A and the second filter unit 11B are formed of surface acoustic wave resonators, the first filter unit 11A and the second filter unit 11B are formed of a single piezoelectric substrate 510. It may be formed on the top. This accelerates the downsizing and the low profile of the transmission filter 11 and the duplexer 1.
　また、第１フィルタ部１１Ａおよび第２フィルタ部１１Ｂの回路構成にかかわらず、第１フィルタ部１１Ａおよび第２フィルタ部１１Ｂは、１チップ化されていることが好ましい。さらには、第１フィルタ部１１Ａ、第２フィルタ部１１Ｂ、および整合回路１３は、１チップ化されていてもよい。これによっても、送信用フィルタ１１およびデュプレクサ１の小型化および低背化が促進される。 Moreover, it is preferable that the first filter unit 11A and the second filter unit 11B are made into one chip regardless of the circuit configuration of the first filter unit 11A and the second filter unit 11B. Furthermore, the first filter unit 11A, the second filter unit 11B, and the matching circuit 13 may be integrated into one chip. This also promotes downsizing and low profile of the transmission filter 11 and the duplexer 1.
　次に、本実施の形態に係るデュプレクサ１の通過特性について、比較例に係るデュプレクサの通過特性と比較しながら説明する。ここでは、まず、比較例に係るデュプレクサが有する送信用フィルタ４１１の回路構成および通過特性について説明する。 Next, the pass characteristics of the duplexer 1 according to the present embodiment will be described in comparison with the pass characteristics of the duplexer according to the comparative example. Here, first, the circuit configuration and pass characteristic of the transmission filter 411 included in the duplexer according to the comparative example will be described.
　［４．比較例に係るデュプレクサの回路構成および通過特性］
　図４は、比較例に係る送信用フィルタ４１１の回路構成図である。図４に示すように、送信用フィルタ４１１は、直列共振子４０１、４０２、４０３、および４０４と、並列共振子４５１、４５２、および４５３とを備える。 [4. Circuit configuration and pass characteristics of duplexer according to comparative example]
FIG. 4 is a circuit configuration diagram of the transmission filter 411 according to the comparative example. As illustrated in FIG. 4, the transmission filter 411 includes series resonators 401, 402, 403, and 404 and parallel resonators 451, 452, and 453.
　直列共振子４０１～４０４は、フィルタ入力端子１４と共通端子３０との間に互いに直列に接続されている。また、並列共振子４５１～４５３は、直列共振子４０１～４０４の各接続点と基準端子（グランド）との間に互いに並列に接続されている。直列共振子４０１～４０４および並列共振子４５１～４５３の上記接続構成により、送信用フィルタ４１１は、ラダー型のバンドパスフィルタを構成している。 The series resonators 401 to 404 are connected in series with each other between the filter input terminal 14 and the common terminal 30. The parallel resonators 451 to 453 are connected in parallel to each other between the connection points of the series resonators 401 to 404 and the reference terminal (ground). With the above connection configuration of the series resonators 401 to 404 and the parallel resonators 451 to 453, the transmission filter 411 constitutes a ladder type band pass filter.
　図５は、比較例に係るデュプレクサの通過特性および各共振子のインピーダンス特性を表すグラフである。より具体的には、図５の上段には、比較例に係るデュプレクサの挿入損失が示されており、送信入力端子１０－共通端子３０間における送信用フィルタ４１１の通過特性と、共通端子３０－受信出力端子２０間における受信用フィルタ１２の通過特性とが同時に示されている。また、図５の下段には、比較例に係るデュプレクサが有する送信用フィルタ４１１の各共振子のインピーダンス特性が示されている。 FIG. 5 is a graph showing the pass characteristic of the duplexer according to the comparative example and the impedance characteristic of each resonator. More specifically, the upper part of FIG. 5 shows the insertion loss of the duplexer according to the comparative example. The transmission characteristic of the transmission filter 411 between the transmission input terminal 10 and the common terminal 30 and the common terminal 30- The pass characteristics of the reception filter 12 between the reception output terminals 20 are simultaneously shown. The lower part of FIG. 5 shows impedance characteristics of the resonators of the transmission filter 411 included in the duplexer according to the comparative example.
　ここで、図４および図５を用いて、複数の直列共振子４０１～４０４および複数の並列共振子４５１～４５３で構成されるラダー型弾性表面波フィルタの動作原理を説明しておく。 Here, the operation principle of the ladder-type surface acoustic wave filter including a plurality of series resonators 401 to 404 and a plurality of parallel resonators 451 to 453 will be described with reference to FIGS.
　並列共振子４５１～４５３は、共振周波数ｆｒｐおよび反共振周波数ｆａｐ（＞ｆｒｐ）を有している。また、直列共振子４０１～４０４は、それぞれ、共振周波数ｆｒｓおよび反共振周波数ｆａｓ（＞ｆｒｓ＞ｆｒｐ）を有している。なお、並列共振子４５１～４５３の各共振周波数は一致していなくてもよく、所定の周波数範囲でばらついていてもよい。また、並列共振子４５１～４５３の各反共振周波数についても一致していなくてもよく、所定の周波数範囲でばらついていてもよい。さらに、直列共振子４０１～４０４の各共振周波数および各反共振周波数も、それぞれ一致していなくてもよく、所定の周波数範囲でばらついていてもよい。 The parallel resonators 451 to 453 have a resonance frequency frp and an anti-resonance frequency fap (> frp). Each of the series resonators 401 to 404 has a resonance frequency frs and an anti-resonance frequency fas (> frs> frp). Note that the resonance frequencies of the parallel resonators 451 to 453 do not have to coincide with each other and may vary within a predetermined frequency range. Further, the antiresonance frequencies of the parallel resonators 451 to 453 may not coincide with each other, and may vary within a predetermined frequency range. Furthermore, the resonance frequencies and antiresonance frequencies of the series resonators 401 to 404 do not have to coincide with each other and may vary within a predetermined frequency range.
　ラダー型の共振子によりバンドパスフィルタを構成するにあたり、並列共振子４５１～４５３の反共振周波数ｆａｐと直列共振子４０１～４０４の共振周波数ｆｒｓとを近接させる。つまり、ｆｒｐ＜ｆｒｓ≒ｆａｐ＜ｆａｓが成立する。これにより、図５に示すように、並列共振子４５１～４５３のインピーダンスが０に近づく共振周波数ｆｒｐ近傍は、送信帯域の低周波側阻止域となる。また、これより周波数が増加すると、反共振周波数ｆａｐ近傍で並列共振子４５１～４５３のインピーダンスが高くなり、かつ、共振周波数ｆｒｓ近傍で直列共振子４０１～４０４のインピーダンスが０に近づく。これにより、反共振周波数ｆａｐ～共振周波数ｆｒｓの近傍では、フィルタ入力端子１４から共通端子３０への信号経路において信号通過域となる。さらに、周波数が高くなり、反共振周波数ｆａｓ近傍になると、直列共振子４０１～４０４のインピーダンスが高くなり、送信帯域の高周波側阻止域となる。 In configuring a band-pass filter with ladder-type resonators, the anti-resonance frequency fap of the parallel resonators 451 to 453 and the resonance frequency frs of the series resonators 401 to 404 are brought close to each other. That is, frp <frs≈fap <fas is established. As a result, as shown in FIG. 5, the vicinity of the resonance frequency frp where the impedances of the parallel resonators 451 to 453 approach zero becomes a low-frequency side stop band of the transmission band. Further, when the frequency is increased, the impedance of the parallel resonators 451 to 453 increases near the antiresonance frequency fap, and the impedance of the series resonators 401 to 404 approaches 0 near the resonance frequency frs. As a result, in the vicinity of the anti-resonance frequency fap to the resonance frequency frs, the signal path from the filter input terminal 14 to the common terminal 30 becomes a signal pass band. Further, when the frequency becomes high and near the anti-resonance frequency fas, the impedance of the series resonators 401 to 404 becomes high, and becomes a high frequency side blocking region of the transmission band.
　上記動作原理に基づいて通過特性が規定されるラダー型弾性表面波フィルタでは、通過帯域および減衰帯域の要求仕様に応じて、直列共振子および並列共振子の段数を最適化することにより、当該要求仕様を満たすフィルタを実現することが可能となる。 In ladder type surface acoustic wave filters whose pass characteristics are defined based on the above operating principle, the number of stages of the series resonator and the parallel resonator is optimized according to the required specifications of the pass band and the attenuation band. A filter satisfying the specifications can be realized.
　しかしながら、ラダー型弾性表面波フィルタは、通過帯域の低損失性、ならびに、通過帯域の低周波端および高周波端での急峻性を確保することに有利な共振特性を有する反面、通過帯域外での挿入損失の跳ね返りが激しいため、通過帯域外での高減衰を確保することが困難である。特に、通過帯域外において、所定の周波数点での高減衰を確保することは容易であるが、例えば、通過帯域が送信帯域である場合の受信帯域全域における高減衰を確保することが困難である。図５の上段に示すように、送信用フィルタ４１１の通過特性において、受信帯域での減衰量を６０ｄＢ確保できていない。 However, the ladder-type surface acoustic wave filter has a resonance characteristic that is advantageous for ensuring low loss in the pass band and steepness at the low frequency end and high frequency end of the pass band, but outside the pass band. It is difficult to ensure high attenuation outside the passband because the insertion loss rebounds severely. In particular, it is easy to ensure high attenuation at a predetermined frequency point outside the pass band, but for example, it is difficult to ensure high attenuation in the entire reception band when the pass band is the transmission band. . As shown in the upper part of FIG. 5, in the pass characteristic of the transmission filter 411, the attenuation in the reception band cannot be secured.
　これに対して、本実施の形態に係るデュプレクサ１の構成によれば、送信帯域の低損失性を確保しつつ受信帯域での高減衰を確保することが可能となる。 On the other hand, according to the configuration of the duplexer 1 according to the present embodiment, it is possible to ensure high attenuation in the reception band while ensuring low loss in the transmission band.
　［５．実施の形態に係るデュプレクサの通過特性］
　図６は、実施の形態に係るデュプレクサ１の通過特性および各共振子のインピーダンス特性を表すグラフである。より具体的には、図６の上段には、実施の形態に係るデュプレクサ１の挿入損失が示されており、送信入力端子１０－共通端子３０間における送信用フィルタ１１の通過特性と、共通端子３０－受信出力端子２０間における受信用フィルタ１２の通過特性とが同時に示されている。また、図６の下段には、実施の形態に係るデュプレクサ１が有する送信用フィルタ１１の各共振子のインピーダンス特性が示されている。 [5. Passage characteristics of duplexer according to embodiment]
FIG. 6 is a graph showing the pass characteristic of the duplexer 1 and the impedance characteristic of each resonator according to the embodiment. More specifically, the upper part of FIG. 6 shows the insertion loss of the duplexer 1 according to the embodiment. The transmission characteristic of the transmission filter 11 between the transmission input terminal 10 and the common terminal 30 and the common terminal The pass characteristic of the reception filter 12 between 30 and the reception output terminal 20 is shown at the same time. 6 shows impedance characteristics of the resonators of the transmission filter 11 included in the duplexer 1 according to the embodiment.
　ここで、実施の形態に係る送信用フィルタ１１の特徴的な構成を、図２および図６を用いて説明する。送信用フィルタ１１は、共通端子３０に接続され、送信帯域の高周波信号を選択的に通過させる特性を有する第１フィルタ部１１Ａと、整合回路１３を介して送信入力端子１０に接続され、受信帯域の高周波信号を選択的に減衰させる特性を有する第２フィルタ部１１Ｂとを備えている。 Here, a characteristic configuration of the transmission filter 11 according to the embodiment will be described with reference to FIGS. The transmission filter 11 is connected to the common terminal 30 and connected to the transmission input terminal 10 via the matching circuit 13 and the first filter unit 11A having a characteristic of selectively allowing a high-frequency signal in the transmission band to pass therethrough. And a second filter unit 11B having a characteristic of selectively attenuating the high frequency signal.
　第１フィルタ部１１Ａは、直列共振子１０１、１０２および１０３と並列共振子１５１および１５２とで構成され、帯域通過機能を有している。 The first filter unit 11A is composed of series resonators 101, 102, and 103 and parallel resonators 151 and 152, and has a band-pass function.
　並列共振子１５１～１５２は、共振周波数ｆｒｐおよび反共振周波数ｆａｐ（＞ｆｒｐ）を有している。また、直列共振子１０１～１０３は、それぞれ、共振周波数ｆｒｓおよび反共振周波数ｆａｓ（＞ｆｒｓ＞ｆｒｐ）を有している。なお、並列共振子１５１および１５２の各共振周波数は一致していなくてもよく、所定の周波数範囲でばらついていてもよい。また、並列共振子１５１および１５２の各反共振周波数についても一致していなくてもよく、所定の周波数範囲でばらついていてもよい。さらに、直列共振子１０１～１０３の各共振周波数および各反共振周波数も、それぞれ一致していなくてもよく、所定の周波数範囲でばらついていてもよい。 The parallel resonators 151 to 152 have a resonance frequency frp and an anti-resonance frequency fap (> frp). The series resonators 101 to 103 each have a resonance frequency frs and an anti-resonance frequency fas (> frs> frp). Note that the resonance frequencies of the parallel resonators 151 and 152 do not have to coincide with each other and may vary within a predetermined frequency range. Further, the antiresonance frequencies of the parallel resonators 151 and 152 may not coincide with each other, and may vary within a predetermined frequency range. Further, the resonance frequencies and the anti-resonance frequencies of the series resonators 101 to 103 do not have to coincide with each other and may vary within a predetermined frequency range.
　第１フィルタ部１１Ａが帯域通過機能を有するにあたり、並列共振子１５１および１５２の反共振周波数ｆａｐと直列共振子１０１～１０３の共振周波数ｆｒｓとを近接させる。つまり、ｆｒｐ＜ｆｒｓ≒ｆａｐ＜ｆａｓが成立する。これにより、図６に示すように、並列共振子１５１および１５２のインピーダンスが０に近づく共振周波数ｆｒｐ近傍は、送信帯域の低周波側阻止域となる。また、これより周波数が増加すると、反共振周波数ｆａｐ近傍で並列共振子１５１および１５２のインピーダンスが高くなり、かつ、共振周波数ｆｒｓ近傍で直列共振子１０１～１０３のインピーダンスが０に近づく。これにより、反共振周波数ｆａｐ～共振周波数ｆｒｓの近傍では、送信入力端子１０から共通端子３０への信号経路において信号通過域となる。さらに、周波数が高くなり、反共振周波数ｆａｓ近傍になると、直列共振子１０１～１０３のインピーダンスが高くなり、送信帯域の高周波側阻止域となる。 When the first filter unit 11A has a band-pass function, the anti-resonance frequency fap of the parallel resonators 151 and 152 and the resonance frequency frs of the series resonators 101 to 103 are brought close to each other. That is, frp <frs≈fap <fas is established. As a result, as shown in FIG. 6, the vicinity of the resonance frequency frp where the impedance of the parallel resonators 151 and 152 approaches 0 becomes a low-frequency side stop band of the transmission band. As the frequency increases, the impedances of the parallel resonators 151 and 152 increase near the anti-resonance frequency fap, and the impedances of the series resonators 101 to 103 approach 0 near the resonance frequency frs. As a result, in the vicinity of the anti-resonance frequency fap to the resonance frequency frs, the signal path from the transmission input terminal 10 to the common terminal 30 becomes a signal pass band. Further, when the frequency becomes high and near the anti-resonance frequency fas, the impedance of the series resonators 101 to 103 becomes high, which becomes a high-frequency side blocking area of the transmission band.
　第２フィルタ部１１Ｂは、第１フィルタ部１１Ａと送信入力端子１０との間に接続された直列共振子１０４と、第１フィルタ部１１Ａから送信入力端子１０までの接続経路と基準端子との間に接続された並列共振子１５３とで構成され、帯域阻止機能を有する。より詳細には、図６の下段に示すように、並列共振子１５３の反共振周波数ｆａｐ３は、送信帯域の帯域外に配されている。また、直列共振子１０４の共振周波数ｆｒｓ４は、並列共振子１５３の反共振周波数ｆａｐ３よりも低く、共振周波数ｆｒｓ４と反共振周波数ｆａｐ３との間に、直列共振子１０４の反共振周波数ｆａｓ４および並列共振子１５３の共振周波数ｆｒｐ３が配されている。また、反共振周波数ｆａｓ４と共振周波数ｆｒｐ３とは、略同一である。つまり、第２フィルタ部１１Ｂでは、ｆｒｓ４＜ｆａｓ４≒ｆｒｐ３＜ｆａｐ３が成立する。これにより、図６に示すように、直列共振子１０４のインピーダンスが０に近づく共振周波数ｆｒｓ４近傍は、送信帯域の高周波側通過域となる。また、これより周波数が増加すると、反共振周波数ｆａｓ４近傍で直列共振子１０４のインピーダンスが高くなり、かつ、共振周波数ｆｒｐ３近傍で並列共振子１５３のインピーダンスが０に近づく。これにより、反共振周波数ｆａｓ４～共振周波数ｆｒｐ３の近傍では、送信入力端子１０から共通端子３０への信号経路において信号阻止域となる。さらに、周波数が高くなり、反共振周波数ｆａｐ３近傍になると、並列共振子１５３のインピーダンスが高くなり、受信帯域外となる。つまり、直列共振子１０４の共振周波数ｆｒｓ４と並列共振子１５３の反共振周波数ｆａｐ３との間の高周波信号が、送信入力端子１０から共通端子３０へ伝搬することを阻止できる。また、並列共振子１５３の反共振周波数ｆａｐ３が、送信帯域の帯域外に配されているので、直列共振子１０４の共振周波数ｆｒｓ４と並列共振子１５３の反共振周波数ｆａｐ３との間の帯域を、送信帯域外の受信帯域に充てることが可能となる。よって、第１フィルタ部１１Ａによる送信帯域の低損失性を確保しつつ、受信帯域の高減衰を達成することが可能となる。 The second filter unit 11B includes a series resonator 104 connected between the first filter unit 11A and the transmission input terminal 10, and a connection path from the first filter unit 11A to the transmission input terminal 10 and the reference terminal. And a parallel resonator 153 connected to each other, and has a band rejection function. More specifically, as shown in the lower part of FIG. 6, the antiresonance frequency fap3 of the parallel resonator 153 is arranged outside the transmission band. The resonance frequency frs4 of the series resonator 104 is lower than the antiresonance frequency fap3 of the parallel resonator 153, and the antiresonance frequency fas4 and parallel resonance of the series resonator 104 are between the resonance frequency frs4 and the antiresonance frequency fap3. The resonance frequency frp3 of the child 153 is arranged. Further, the antiresonance frequency fas4 and the resonance frequency frp3 are substantially the same. That is, frs4 <fas4≈frp3 <fap3 is established in the second filter unit 11B. As a result, as shown in FIG. 6, the vicinity of the resonance frequency frs4 in which the impedance of the series resonator 104 approaches 0 becomes a high-frequency side passband of the transmission band. Further, when the frequency is increased, the impedance of the series resonator 104 increases near the antiresonance frequency fas4, and the impedance of the parallel resonator 153 approaches 0 near the resonance frequency frp3. As a result, in the vicinity of the anti-resonance frequency fas4 to the resonance frequency frp3, a signal blocking region is provided in the signal path from the transmission input terminal 10 to the common terminal 30. Further, when the frequency becomes high and becomes near the anti-resonance frequency fap3, the impedance of the parallel resonator 153 becomes high and falls outside the reception band. That is, a high frequency signal between the resonance frequency frs4 of the series resonator 104 and the anti-resonance frequency fap3 of the parallel resonator 153 can be prevented from propagating from the transmission input terminal 10 to the common terminal 30. Further, since the anti-resonance frequency fap3 of the parallel resonator 153 is arranged outside the band of the transmission band, a band between the resonance frequency frs4 of the series resonator 104 and the anti-resonance frequency fap3 of the parallel resonator 153 is It is possible to use the reception band outside the transmission band. Therefore, it is possible to achieve high attenuation of the reception band while ensuring low loss of the transmission band by the first filter unit 11A.
　ここで、直列共振子１０４の反共振周波数ｆａｓ４および並列共振子１５３の共振周波数ｆｒｐ３は、受信帯域に配されていることが好ましい。これにより、送信入力端子１０から共通端子３０への伝搬方向において高インピーダンスとなる反共振周波数ｆａｓ４または共振周波数ｆｒｐ３の高周波信号は、高度に阻止される。よって、通過帯域外である受信帯域の減衰特性を最適化することが可能となる。なお、反共振周波数ｆａｓ４および共振周波数ｆｒｐ３が受信帯域に配されているとは、反共振周波数ｆａｓ４および共振周波数ｆｒｐ３が受信帯域内に配されていることに限定されない。例えば、受信帯域内の減衰特性の周波数依存性が激しい場合には、反共振周波数ｆａｓ４および共振周波数ｆｒｐ３を受信帯域に近接する低周波領域または高周波領域に配してもよく、この場合には、受信帯域全域にわたり、高減衰を確保することが可能となる。 Here, the antiresonance frequency fas4 of the series resonator 104 and the resonance frequency frp3 of the parallel resonator 153 are preferably arranged in the reception band. As a result, the high-frequency signal having the anti-resonance frequency fas4 or the resonance frequency frp3 that has a high impedance in the propagation direction from the transmission input terminal 10 to the common terminal 30 is highly blocked. Therefore, it is possible to optimize the attenuation characteristic of the reception band outside the pass band. The anti-resonance frequency fas4 and the resonance frequency frp3 being arranged in the reception band are not limited to the anti-resonance frequency fas4 and the resonance frequency frp3 being arranged in the reception band. For example, when the frequency dependence of the attenuation characteristic in the reception band is severe, the anti-resonance frequency fas4 and the resonance frequency frp3 may be arranged in a low frequency region or a high frequency region close to the reception band. It is possible to ensure high attenuation over the entire reception band.
　なお、本実施の形態に係る送信用フィルタ１１において、減衰帯域の帯域幅を調整したい場合には、直列共振子１０４の反共振周波数ｆａｓ４および並列共振子１５３の共振周波数ｆｒｐ３を調整してもよい。例えば、減衰帯域を広帯域化したい場合には、直列共振子１０４の反共振周波数ｆａｓ４を低周波側へシフトさせ、並列共振子１５３の共振周波数ｆｒｐ３を高周波側へシフトさせてもよい。 In the transmission filter 11 according to the present embodiment, when it is desired to adjust the bandwidth of the attenuation band, the antiresonance frequency fas4 of the series resonator 104 and the resonance frequency frp3 of the parallel resonator 153 may be adjusted. . For example, when it is desired to increase the attenuation band, the antiresonance frequency fas4 of the series resonator 104 may be shifted to the low frequency side, and the resonance frequency frp3 of the parallel resonator 153 may be shifted to the high frequency side.
　図７Ａは、実施の形態および比較例に係るデュプレクサの通過特性を比較したグラフである。図７Ａに示すように、本実施の形態に係るデュプレクサ１の通過帯域内の挿入損失は、比較例に係るデュプレクサの通過帯域内の挿入損失と、ほぼ同等レベルである。これに対して、本実施の形態に係る送信用フィルタ１１の受信帯域の減衰特性は、比較例に係る送信用フィルタ４１１の受信帯域の減衰特性と比較して、１０ｄＢ以上向上していることが解る。 FIG. 7A is a graph comparing pass characteristics of the duplexers according to the embodiment and the comparative example. As shown in FIG. 7A, the insertion loss in the pass band of the duplexer 1 according to the present embodiment is substantially equal to the insertion loss in the pass band of the duplexer according to the comparative example. On the other hand, the reception band attenuation characteristic of the transmission filter 11 according to the present embodiment is improved by 10 dB or more compared to the reception band attenuation characteristic of the transmission filter 411 according to the comparative example. I understand.
　図７Ｂは、実施の形態および比較例に係るデュプレクサのアイソレーション特性を比較したグラフである。図７Ｂに示すように、本実施の形態に係るデュプレクサ１の送信用フィルタ１１と受信用フィルタ１２との間のアイソレーションについても、比較例に係るデュプレクサの送信用フィルタ４１１と受信用フィルタ１２との間のアイソレーションと比較して、１０ｄＢ以上向上していることが解る。 FIG. 7B is a graph comparing the isolation characteristics of the duplexers according to the embodiment and the comparative example. As shown in FIG. 7B, the isolation between the transmission filter 11 and the reception filter 12 of the duplexer 1 according to the present embodiment also includes the transmission filter 411 and the reception filter 12 of the duplexer according to the comparative example. It can be seen that there is an improvement of 10 dB or more compared to the isolation between the two.
　［６．インピーダンス整合回路の構成］
　なお、本実施の形態に係る送信用フィルタ１１は、帯域阻止機能を有する第２フィルタ部１１Ｂを有しているため、送信入力端子１０に接続される外部回路と送信用フィルタ１１とのインピーダンスが整合しないことが想定される。これに対して、本実施の形態に係るデュプレクサ１は、送信側フィルタ回路として、送信入力端子１０接続された整合回路１３を備えている。以下、整合回路１３の作用効果について、図８Ａおよび図８Ｂを用いて説明する。 [6. Configuration of impedance matching circuit]
The transmission filter 11 according to the present embodiment includes the second filter unit 11B having a band rejection function, so that the impedance between the external circuit connected to the transmission input terminal 10 and the transmission filter 11 is low. Inconsistencies are assumed. In contrast, the duplexer 1 according to the present embodiment includes a matching circuit 13 connected to the transmission input terminal 10 as a transmission-side filter circuit. Hereinafter, the effect of the matching circuit 13 will be described with reference to FIGS. 8A and 8B.
　図８Ａは、整合回路１３が付加される前の、実施の形態に係る送信用フィルタ１１のスミスチャートである。同図の左側には、本実施の形態に係るデュプレクサ１を含むフロントエンド回路の構成が示されており、同図の右側には、フィルタ入力端子１４から送信用フィルタ１１を見た場合の複素インピーダンスを表すスミスチャートが示されている。ここで、図８Ａに示されたフロントエンド回路では、送信入力端子１０と第２フィルタ部１１Ｂとの間には整合回路１３が配置されていない。 FIG. 8A is a Smith chart of the transmission filter 11 according to the embodiment before the matching circuit 13 is added. The left side of the figure shows the configuration of the front-end circuit including the duplexer 1 according to the present embodiment. The right side of the figure shows the complex when the transmission filter 11 is viewed from the filter input terminal 14. A Smith chart representing impedance is shown. Here, in the front end circuit shown in FIG. 8A, the matching circuit 13 is not disposed between the transmission input terminal 10 and the second filter unit 11B.
　この場合、図８Ａの右側のスミスチャートに示されるように、通過帯域である送信帯域のインピーダンスは容量性を示し、特性インピーダンスから外れている。この場合、送信用フィルタ１１の送信帯域内の挿入損失は劣化する。 In this case, as shown in the Smith chart on the right side of FIG. In this case, the insertion loss in the transmission band of the transmission filter 11 deteriorates.
　図８Ｂは、整合回路１３が付加された、実施の形態に係る送信用フィルタ１１のスミスチャートである。同図の左側には、本実施の形態に係るデュプレクサ１を含むフロントエンド回路の構成が示されており、同図の右側には、送信入力端子１０から送信用フィルタ１１を見た場合の複素インピーダンスを表すスミスチャートが示されている。ここで、図８Ｂに示されたフロントエンド回路では、送信入力端子１０と第２フィルタ部１１Ｂとの間に、整合回路１３が配置されている。 FIG. 8B is a Smith chart of the transmission filter 11 according to the embodiment to which the matching circuit 13 is added. The left side of the figure shows the configuration of the front end circuit including the duplexer 1 according to the present embodiment, and the right side of the figure shows the complex when the transmission filter 11 is viewed from the transmission input terminal 10. A Smith chart representing impedance is shown. Here, in the front end circuit shown in FIG. 8B, the matching circuit 13 is arranged between the transmission input terminal 10 and the second filter unit 11B.
　整合回路１３は、例えば、インダクタ１３１とキャパシタ１３２とを有する。インダクタ１３１は、送信入力端子１０およびフィルタ入力端子１４に接続されている。キャパシタ１３２は、送信入力端子１０および基準端子に接続されている。図８Ａに示すように、整合回路１３が付加されていない場合の送信用フィルタ１１の送信帯域内インピーダンスは、容量性を示す。これに対して、図８Ｂでは、第２フィルタ部１１Ｂと送信入力端子１０との間に、所定のインダクタンス値（１５ｎＨ）を有するインダクタ１３１が直列接続され、所定のキャパシタンス値（２．０ｐＦ）を有するキャパシタ１３２が並列接続されている。整合回路１３の付加により、図８Ｂに示すように、送信用フィルタ１１の送信帯域内インピーダンスは特性インピーダンス（中央付近）にシフトするので、送信用フィルタ１１の送信帯域内の挿入損失は劣化しない。さらに、受信帯域のインピーダンスは、整合回路１３を付加した図８Ｂの方が、高インピーダンスとなっているため、受信帯域における減衰量も向上させることが可能となる。つまり、送信入力端子１０と第２フィルタ部１１Ｂとの間に整合回路１３が接続されることにより、送信用フィルタ１１と外部回路とのインピーダンス整合をとることができ、送信帯域の高周波信号を、より低損失で通過させることが可能となる。 The matching circuit 13 includes, for example, an inductor 131 and a capacitor 132. The inductor 131 is connected to the transmission input terminal 10 and the filter input terminal 14. The capacitor 132 is connected to the transmission input terminal 10 and the reference terminal. As shown in FIG. 8A, the transmission band impedance of the transmission filter 11 in the case where the matching circuit 13 is not added indicates capacitance. On the other hand, in FIG. 8B, an inductor 131 having a predetermined inductance value (15 nH) is connected in series between the second filter unit 11B and the transmission input terminal 10, and a predetermined capacitance value (2.0 pF) is obtained. A capacitor 132 having the same is connected in parallel. By adding the matching circuit 13, as shown in FIG. 8B, the transmission band impedance of the transmission filter 11 is shifted to the characteristic impedance (near the center), so that the insertion loss in the transmission band of the transmission filter 11 is not deteriorated. Furthermore, the impedance of the reception band is higher in FIG. 8B to which the matching circuit 13 is added, so that the attenuation in the reception band can be improved. That is, by connecting the matching circuit 13 between the transmission input terminal 10 and the second filter unit 11B, impedance matching between the transmission filter 11 and the external circuit can be achieved, and a high-frequency signal in the transmission band is It is possible to pass through with lower loss.
　なお、本実施の形態では、第２フィルタ部１１Ｂと送信入力端子１０との間に整合回路１３を付加したが、整合回路１３は必須の構成要素ではない。整合回路１３は、デュプレクサ１の要求仕様により、適宜配置されればよい。 In the present embodiment, the matching circuit 13 is added between the second filter unit 11B and the transmission input terminal 10, but the matching circuit 13 is not an essential component. The matching circuit 13 may be appropriately arranged according to the required specifications of the duplexer 1.
　また、本実施の形態では、第２フィルタ部１１Ｂは、第１フィルタ部１１Ａとフィルタ入力端子１４との間に配置されているが、第２フィルタ部１１Ｂは、共通端子３０と第１フィルタ部１１Ａとの間に配置されてもよい。ただし、この配置構成をとる場合には、共通端子３０に接続されるアンテナ素子２と送信用フィルタ１１とのインピーダンスが整合しないことが想定される。これに対して、整合回路１３を、共通端子３０と第２フィルタ部１１Ｂとの間に接続配置することにより、アンテナ素子２と送信用フィルタ１１とのインピーダンス整合をとることが可能となる。 In the present embodiment, the second filter unit 11B is disposed between the first filter unit 11A and the filter input terminal 14. However, the second filter unit 11B includes the common terminal 30 and the first filter unit. It may be arranged between 11A. However, when this arrangement configuration is adopted, it is assumed that the impedances of the antenna element 2 connected to the common terminal 30 and the transmission filter 11 do not match. On the other hand, impedance matching between the antenna element 2 and the transmission filter 11 can be achieved by connecting and arranging the matching circuit 13 between the common terminal 30 and the second filter unit 11B.
　つまり、本実施の形態に係る送信用フィルタ１１および整合回路１３を備えた高周波フィルタ素子は、共通端子３０に接続され、送信帯域の高周波信号を通過させる帯域通過機能を有する第１フィルタ部１１Ａと、送信入力端子１０と第１フィルタ部１１Ａとの間に接続され、受信帯域の高周波信号を減衰させる帯域阻止機能を有する第２フィルタ部１１Ｂとを備える。第２フィルタ部１１Ｂは、直列共振子１０４と並列共振子１５３とを有し、並列共振子１５３の反共振周波数ｆａｐ３は送信帯域の帯域外に配され、直列共振子１０４の共振周波数ｆｒｓ４は並列共振子１５３の反共振周波数ｆａｐ３よりも低く、共振周波数ｆｒｓ４と反共振周波数ｆａｐ３との間に直列共振子１０４の反共振周波数ｆａｓ４および並列共振子１５３の共振周波数ｆｒｐ３が配されている。さらに、高周波フィルタ素子は、送信入力端子１０に接続された整合回路１３を備える。 That is, the high-frequency filter element including the transmission filter 11 and the matching circuit 13 according to the present embodiment is connected to the common terminal 30 and has a first filter unit 11A having a band-pass function for passing a high-frequency signal in the transmission band. And a second filter unit 11B connected between the transmission input terminal 10 and the first filter unit 11A and having a band rejection function for attenuating a high-frequency signal in the reception band. The second filter unit 11B includes a series resonator 104 and a parallel resonator 153, the antiresonance frequency fap3 of the parallel resonator 153 is arranged outside the transmission band, and the resonance frequency frs4 of the series resonator 104 is parallel. The anti-resonance frequency fap3 of the series resonator 104 and the resonance frequency frp3 of the parallel resonator 153 are arranged between the resonance frequency frs4 and the anti-resonance frequency fap3. Further, the high frequency filter element includes a matching circuit 13 connected to the transmission input terminal 10.
　これにより、第１フィルタ部１１Ａによる送信帯域の低損失性を確保しつつ、受信帯域の高減衰を達成することが可能となる。また、整合回路１３の付加により、高周波フィルタ素子と外部回路とのインピーダンス整合をとることができ、送信帯域の高周波信号を、より低損失で通過させることが可能となる。 This makes it possible to achieve high attenuation of the reception band while ensuring low loss of the transmission band by the first filter unit 11A. Further, by adding the matching circuit 13, impedance matching between the high frequency filter element and the external circuit can be achieved, and a high frequency signal in the transmission band can be passed with lower loss.
　［７．デュプレクサ間のクロスアイソレーション］
　上記実施の形態では、１つのデュプレクサ１内での通過特性、減衰特性、および送受信間のアイソレーションを向上させる構成を説明してきたが、本変形例では、異なるデュプレクサ間におけるアイソレーション（クロスアイソレーション）を向上させる本発明の構成について説明する。 [7. Cross isolation between duplexers]
In the above-described embodiment, the configuration for improving the pass characteristics, attenuation characteristics, and transmission / reception isolation within one duplexer 1 has been described. However, in this modification, isolation between different duplexers (cross isolation) ) Will be described.
　本変形例では、ＬＴＥ規格のＢａｎｄ１（送信通過帯域：１９２０－１９８０ＭＨｚ、受信通過帯域：２１１０－２１７０ＭＨｚ）およびＢａｎｄ３（送信通過帯域：１７１０－１７８５ＭＨｚ、受信通過帯域：１８０５－１８８０ＭＨｚ）に適用されるクワッドプレクサについて例示する。 In this modification, quads applied to Band 1 (transmission pass band: 1920-1980 MHz, reception pass band: 2110-2170 MHz) and Band 3 (transmission pass band: 1710-1785 MHz, reception pass band: 1805-1880 MHz) of the LTE standard. An example of a plexer will be described.
　本変形例に係るクワッドプレクサ４は、Ｂａｎｄ１の送信側フィルタ回路およびＢａｎｄ１の受信側フィルタ回路と、Ｂａｎｄ３の送信側フィルタ回路およびＢａｎｄ３の受信側フィルタ回路とが共通端子で束ねられたマルチプレクサである。 The quadplexer 4 according to this modification is a multiplexer in which a Band1 transmission filter circuit and a Band1 reception filter circuit, a Band3 transmission filter circuit, and a Band3 reception filter circuit are bundled at a common terminal. .
　図９は、実施の形態の変形例に係るクワッドプレクサ４および周辺回路の回路構成図である。同図に示すように、クワッドプレクサ４は、送信用フィルタ１６（第１送信側フィルタ回路）および２６（第２送信側フィルタ回路）と、受信用フィルタ１７（第１受信側フィルタ回路）および２７（第２受信側フィルタ回路）と、整合回路２３と、送信入力端子４１（第１送信入力端子）および５１（第２送信入力端子）と、受信出力端子４２（第１受信出力端子）および５２（第２受信出力端子）と、共通端子３０とを備える。送信用フィルタ１６と整合回路２３とは、高周波フィルタ素子を構成している。送信用フィルタ１６および受信用フィルタ１７、ならびに整合回路２３は、デュプレクサ１Ａ（第１デュプレクサ）を構成している。送信用フィルタ２６および受信用フィルタ２７は、デュプレクサ１Ｂ（第２デュプレクサ）を構成している。また、デュプレクサ１Ａおよび１Ｂ、アンテナ素子２、ならびにアンテナ整合回路３は、フロントエンド回路を構成している。 FIG. 9 is a circuit configuration diagram of the quadplexer 4 and peripheral circuits according to a modification of the embodiment. As shown in the figure, the quadplexer 4 includes transmission filters 16 (first transmission filter circuit) and 26 (second transmission filter circuit), reception filter 17 (first reception filter circuit), and 27 (second reception side filter circuit), matching circuit 23, transmission input terminal 41 (first transmission input terminal) and 51 (second transmission input terminal), reception output terminal 42 (first reception output terminal), and 52 (second reception output terminal) and a common terminal 30. The transmission filter 16 and the matching circuit 23 constitute a high frequency filter element. The transmission filter 16, the reception filter 17, and the matching circuit 23 constitute a duplexer 1A (first duplexer). The transmission filter 26 and the reception filter 27 constitute a duplexer 1B (second duplexer). Further, the duplexers 1A and 1B, the antenna element 2, and the antenna matching circuit 3 constitute a front end circuit.
　アンテナ整合回路３は、アンテナ素子２、デュプレクサ１Ａおよび１Ｂに接続され、アンテナ素子２とデュプレクサ１Ａとのインピーダンス整合、および、アンテナ素子２とデュプレクサ１Ｂとのインピーダンス整合をとる回路である。これにより、デュプレクサ１Ａおよび１Ｂは、アンテナ素子２から低損失で受信信号を受信し、送信信号を低損失でアンテナ素子２へ出力することが可能となる。アンテナ整合回路３は、１以上の高周波回路部品で構成されており、例えば、チップ状のインダクタおよびチップ状のコンデンサからなる。なお、アンテナ整合回路３は、フロントエンド回路の必須構成要素ではない。 The antenna matching circuit 3 is connected to the antenna element 2 and the duplexers 1A and 1B, and performs impedance matching between the antenna element 2 and the duplexer 1A, and impedance matching between the antenna element 2 and the duplexer 1B. Thereby, the duplexers 1A and 1B can receive the received signal from the antenna element 2 with low loss and output the transmission signal to the antenna element 2 with low loss. The antenna matching circuit 3 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor. The antenna matching circuit 3 is not an essential component of the front end circuit.
　送信用フィルタ１６は、高周波信号処理回路（ＲＦＩＣなど）で生成されパワーアンプを経由して増幅された送信信号を、送信入力端子４１を経由して入力し、Ｂａｎｄ３の第１送信帯域（第１周波数帯域）でフィルタリングして共通端子３０へ出力する帯域通過フィルタである。また、送信入力端子４１と送信用フィルタ１６との間には、整合回路２３が接続されている。 The transmission filter 16 inputs a transmission signal generated by a high-frequency signal processing circuit (RFIC or the like) and amplified via a power amplifier via a transmission input terminal 41, and transmits a first transmission band (first) of Band3. This is a band-pass filter that performs filtering in the frequency band and outputs to the common terminal 30. A matching circuit 23 is connected between the transmission input terminal 41 and the transmission filter 16.
　受信用フィルタ１７は、共通端子３０から入力された受信信号を入力し、Ｂａｎｄ３の第１受信帯域でフィルタリングして受信出力端子４２へ出力する帯域通過フィルタである。 The reception filter 17 is a band-pass filter that receives the reception signal input from the common terminal 30, filters the first reception band of Band 3, and outputs the filtered signal to the reception output terminal 42.
　送信用フィルタ２６は、高周波信号処理回路（ＲＦＩＣなど）で生成されパワーアンプを経由して増幅された送信信号を、送信入力端子５１を経由して入力し、Ｂａｎｄ１の第２送信帯域でフィルタリングして共通端子３０へ出力する帯域通過フィルタである。 The transmission filter 26 inputs a transmission signal generated by a high-frequency signal processing circuit (RFIC or the like) and amplified via a power amplifier via the transmission input terminal 51, and filters it in the second transmission band of Band1. This is a band-pass filter that outputs to the common terminal 30.
　受信用フィルタ２７は、共通端子３０から入力された受信信号を入力し、Ｂａｎｄ１の第２受信帯域（第２周波数帯域）でフィルタリングして受信出力端子５２へ出力する帯域通過フィルタである。 The reception filter 27 is a band-pass filter that receives the reception signal input from the common terminal 30, filters it in the second reception band (second frequency band) of Band 1 and outputs it to the reception output terminal 52.
　送信用フィルタ１６および２６ならびに受信用フィルタ１７および２７は、共通端子３０に接続されている。 The transmission filters 16 and 26 and the reception filters 17 and 27 are connected to the common terminal 30.
　整合回路２３は、送信用フィルタ１６のフィルタ入力端子２４および送信入力端子４１に接続され、送信入力端子４１に接続されるパワーアンプなどの外部回路と送信用フィルタ１６とのインピーダンス整合をとるインピーダンス整合回路である。これにより、デュプレクサ１Ａは、外部回路から低損失で送信信号を入力することが可能となる。整合回路２３は、１以上の高周波回路部品で構成されており、例えば、チップ状のインダクタおよびチップ状のコンデンサ、または、基板上に形成された配線パターンからなる。なお、整合回路２３は、共通端子３０と送信用フィルタ１６との間に接続されていてもよい。 The matching circuit 23 is connected to the filter input terminal 24 and the transmission input terminal 41 of the transmission filter 16, and impedance matching is performed for impedance matching between the transmission circuit 16 and an external circuit such as a power amplifier connected to the transmission input terminal 41. Circuit. As a result, the duplexer 1A can input a transmission signal with low loss from an external circuit. The matching circuit 23 is composed of one or more high-frequency circuit components, and includes, for example, a chip-shaped inductor and a chip-shaped capacitor, or a wiring pattern formed on a substrate. The matching circuit 23 may be connected between the common terminal 30 and the transmission filter 16.
　なお、本変形例では、本発明に係るマルチプレクサとしてクワッドプレクサ４を挙げているが、本発明に係るマルチプレクサは、上述したように、クワッドプレクサ４に限定されず、トリプレクサ、ペンタプレクサ、およびそれ以上のバンド数を有するマルチプレクサにも適用される。 In this modification, the quadplexer 4 is cited as the multiplexer according to the present invention. However, as described above, the multiplexer according to the present invention is not limited to the quadplexer 4, and is a triplexer, a pentaplexer, and the like. The present invention is also applied to a multiplexer having the above number of bands.
　図１０は、実施の形態の変形例に係る送信用フィルタ１６の回路構成図である。図１０に示すように、送信用フィルタ１６は、第１フィルタ部１１Ａと第２フィルタ部１１Ｂと第３フィルタ部１１Ｃとが縦続接続された構成を有する。 FIG. 10 is a circuit configuration diagram of the transmission filter 16 according to a modification of the embodiment. As shown in FIG. 10, the transmission filter 16 has a configuration in which a first filter unit 11A, a second filter unit 11B, and a third filter unit 11C are connected in cascade.
　第１フィルタ部１１Ａは、共通端子３０（第１端子）に接続され、直列共振子１０１、１０２および１０３と、並列共振子１５１および１５２とを備え、Ｂａｎｄ３の第１送信帯域（第１周波数帯域）の高周波信号を選択的に通過させる特性を有する。 The first filter unit 11A is connected to the common terminal 30 (first terminal), includes series resonators 101, 102, and 103, and parallel resonators 151 and 152, and has a first transmission band (first frequency band) of Band3. ) To selectively pass high-frequency signals.
　第３フィルタ部１１Ｃは、第１フィルタ部１１Ａとフィルタ入力端子２４との間に配置され、直列共振子１０４と並列共振子１５３とを備え、第１送信帯域と異なるＢａｎｄ３の第１受信帯域の高周波信号を選択的に減衰させる特性を有する。 The third filter unit 11C is disposed between the first filter unit 11A and the filter input terminal 24, includes a series resonator 104 and a parallel resonator 153, and has a first reception band of Band3 different from the first transmission band. It has a characteristic of selectively attenuating a high frequency signal.
　第２フィルタ部１１Ｂは、第１フィルタ部１１Ａとフィルタ入力端子２４との間に配置され、整合回路２３を介して送信入力端子４１（第２端子）に接続され、直列共振子１０５と並列共振子１５４とを備え、第１送信帯域および第１受信帯域と異なるＢａｎｄ１の第２受信帯域（第２周波数帯域）の高周波信号を選択的に減衰させる特性を有する。 The second filter unit 11B is disposed between the first filter unit 11A and the filter input terminal 24, is connected to the transmission input terminal 41 (second terminal) via the matching circuit 23, and is in parallel resonance with the series resonator 105. And has a characteristic of selectively attenuating a high-frequency signal in a second reception band (second frequency band) of Band 1 different from the first transmission band and the first reception band.
　直列共振子１０１～１０５は、フィルタ入力端子２４と共通端子３０との間に互いに直列に接続されている。また、並列共振子１５１～１５４は、直列共振子１０１～１０５の各接続点と基準端子（グランド）との間に互いに並列に接続されている。直列共振子１０１～１０３および並列共振子１５１～１５２の上記接続構成により、第１フィルタ部１１Ａは、帯域通過機能を有する。また、直列共振子１０４および並列共振子１５３の上記接続構成により、第３フィルタ部１１Ｃは、Ｂａｎｄ３の第１受信帯域の帯域阻止機能を有する。また、直列共振子１０５および並列共振子１５４の上記接続構成により、第２フィルタ部１１Ｂは、Ｂａｎｄ１の第２受信帯域の帯域阻止機能を有する。送信用フィルタ１６は、第１フィルタ部１１Ａと第３フィルタ部１１Ｃと第２フィルタ部１１Ｂとの縦続接続により、全体として、ラダー型のバンドパスフィルタを構成している。 The series resonators 101 to 105 are connected in series with each other between the filter input terminal 24 and the common terminal 30. The parallel resonators 151 to 154 are connected in parallel to each other between the connection points of the series resonators 101 to 105 and the reference terminal (ground). With the connection configuration of the series resonators 101 to 103 and the parallel resonators 151 to 152, the first filter unit 11A has a band pass function. Further, due to the connection configuration of the series resonator 104 and the parallel resonator 153, the third filter unit 11C has a band rejection function of the first reception band of Band3. Further, due to the above-described connection configuration of the series resonator 105 and the parallel resonator 154, the second filter unit 11B has a band rejection function of the second reception band of Band1. The transmission filter 16 constitutes a ladder-type bandpass filter as a whole by the cascade connection of the first filter unit 11A, the third filter unit 11C, and the second filter unit 11B.
　なお、第１フィルタ部１１Ａは、ラダー型の弾性表面波素子の構成を有していなくてもよい。第１フィルタ部１１Ａの回路構成は、送信用フィルタ１６の要求仕様に応じて、例えば、縦結合型の弾性表面波素子などであってもよく、または、ＢＡＷを用いた弾性波共振子で構成されていてもよい。さらには、弾性波素子の構成を有していなくてもよく、その他のフィルタ構造を有していてもよい。 Note that the first filter portion 11A may not have a configuration of a ladder-type surface acoustic wave element. The circuit configuration of the first filter unit 11A may be, for example, a longitudinally coupled surface acoustic wave element or the like according to the required specifications of the transmission filter 16, or configured by an elastic wave resonator using BAW. May be. Furthermore, it may not have the structure of an acoustic wave element, and may have another filter structure.
　また、本変形例に係るクワッドプレクサ４では、送信用フィルタ２６、受信用フィルタ１７および２７の回路構成は、特に限定されない。送信用フィルタ２６、受信用フィルタ１７および２７は、その要求仕様に応じて、例えば、ラダー型の弾性表面波素子、縦結合型の弾性表面波素子などであってもよい。送信用フィルタ１１および２６ならびに受信用フィルタ１７および２７がともに弾性表面波素子で構成される場合には、これらを１枚の圧電基板上に形成することが可能となり、小型化が実現できる。また、送信用フィルタ２６、受信用フィルタ１７および２７は、ＢＡＷを用いた弾性波共振子で構成されていてもよく、さらには、弾性波素子の構成を有していなくてもよく、その他のフィルタ構造を有していてもよい。 Further, in the quadplexer 4 according to this modification, the circuit configurations of the transmission filter 26 and the reception filters 17 and 27 are not particularly limited. The transmission filter 26 and the reception filters 17 and 27 may be, for example, a ladder type surface acoustic wave element, a longitudinally coupled type surface acoustic wave element, or the like according to the required specifications. When the transmission filters 11 and 26 and the reception filters 17 and 27 are both composed of surface acoustic wave elements, they can be formed on a single piezoelectric substrate, and downsizing can be realized. Further, the transmission filter 26 and the reception filters 17 and 27 may be constituted by elastic wave resonators using BAW, and may not have an elastic wave element configuration. It may have a filter structure.
　ここで、第３フィルタ部１１Ｃは、実施の形態に係るデュプレクサ１における第２フィルタ部１１Ｂに相当し、直列共振子１０４および並列共振子１５３の共振インピーダンス特性は、図６下段に示された直列共振子１０４および並列共振子１５３と同様のインピーダンス特性を示す。つまり、並列共振子１５４の反共振周波数は、第１送信帯域の帯域外に配され、直列共振子１０４の共振周波数は並列共振子１５３の反共振周波数よりも低く、直列共振子１０４の共振周波数と並列共振子１５３の反共振周波数との間に、直列共振子１０４の反共振周波数および並列共振子１５３の共振周波数が配されている。さらに、直列共振子１０４の反共振周波数および並列共振子１５３の共振周波数は、Ｂａｎｄ３の第１受信帯域に配されている。これにより、デュプレクサ１Ａにおける第１送信帯域の低損失性を確保しつつ、デュプレクサ１Ａの第１受信帯域の高減衰を達成することが可能となる。また、デュプレクサ１Ａの送信用フィルタ１６と受信用フィルタ１７との間のアイソレーション（図９のＩｓｏＸ）を向上させることが可能となる。 Here, the third filter unit 11C corresponds to the second filter unit 11B in the duplexer 1 according to the embodiment, and the resonance impedance characteristics of the series resonator 104 and the parallel resonator 153 are the series shown in the lower stage of FIG. Impedance characteristics similar to those of the resonator 104 and the parallel resonator 153 are shown. That is, the antiresonance frequency of the parallel resonator 154 is arranged outside the first transmission band, the resonance frequency of the series resonator 104 is lower than the antiresonance frequency of the parallel resonator 153, and the resonance frequency of the series resonator 104. And the antiresonance frequency of the parallel resonator 153, the antiresonance frequency of the series resonator 104 and the resonance frequency of the parallel resonator 153 are arranged. Furthermore, the antiresonance frequency of the series resonator 104 and the resonance frequency of the parallel resonator 153 are arranged in the first reception band of Band3. Accordingly, it is possible to achieve high attenuation of the first reception band of the duplexer 1A while ensuring low loss of the first transmission band in the duplexer 1A. Further, it is possible to improve the isolation (IsoX in FIG. 9) between the transmission filter 16 and the reception filter 17 of the duplexer 1A.
　本変形例では、さらに、第２フィルタ部１１Ｂにおいて、直列共振子１０５および並列共振子１５４の共振インピーダンス特性は、図６下段に示された直列共振子１０４および並列共振子１５３と同様のインピーダンス特性を示す。つまり、並列共振子１５４の反共振周波数は、第１送信帯域の帯域外に配され、直列共振子１０５の共振周波数は並列共振子１５４の反共振周波数よりも低く、直列共振子１０５の共振周波数と並列共振子１５４の反共振周波数との間に、直列共振子１０５の反共振周波数および並列共振子１５４の共振周波数が配されている。さらに、直列共振子１０５の反共振周波数および並列共振子１５４の共振周波数は、Ｂａｎｄ１の第２受信帯域（第２周波数帯域）に配されている。これによれば、Ｂａｎｄ３の送信用フィルタ１６が、第２フィルタ部１１Ｂの構成を有していることで、デュプレクサ１Ａにおける第１送信帯域の低損失性を確保しつつ、デュプレクサ１Ａの第２受信帯域の高減衰を達成することが可能となる。さらに、Ｂａｎｄ３の送信用フィルタ１６とＢａｎｄ１の受信用フィルタ２７とのクロスアイソレーション（図９のＩｓｏＹ）を向上させることが可能となる。 In the present modification, furthermore, in the second filter unit 11B, the resonance impedance characteristics of the series resonator 105 and the parallel resonator 154 are the same as those of the series resonator 104 and the parallel resonator 153 shown in the lower part of FIG. Indicates. That is, the antiresonance frequency of the parallel resonator 154 is arranged outside the first transmission band, the resonance frequency of the series resonator 105 is lower than the antiresonance frequency of the parallel resonator 154, and the resonance frequency of the series resonator 105. And the anti-resonance frequency of the parallel resonator 154, the anti-resonance frequency of the series resonator 105 and the resonance frequency of the parallel resonator 154 are arranged. Furthermore, the antiresonance frequency of the series resonator 105 and the resonance frequency of the parallel resonator 154 are arranged in the second reception band (second frequency band) of Band1. According to this, since the transmission filter 16 of Band3 has the configuration of the second filter unit 11B, the second reception of the duplexer 1A is ensured while ensuring low loss of the first transmission band in the duplexer 1A. It becomes possible to achieve high attenuation of the band. Furthermore, cross-isolation (IsoY in FIG. 9) between the Band3 transmission filter 16 and the Band1 reception filter 27 can be improved.
　なお、本変形例では、Ｂａｎｄ３の送信用フィルタ１６に、特徴のある構成、つまり第１フィルタ部１１Ａ、第２フィルタ部１１Ｂ、および第３フィルタ部１１Ｃを有する構成例を示したが、当該特徴の構成を有するフィルタは、受信用フィルタ１７、２７、または、送信用フィルタ２６であってもよい。また、第３フィルタ部１１Ｃはなくてもよい。 In this modification, the Band3 transmission filter 16 has a characteristic configuration, that is, a configuration example having the first filter unit 11A, the second filter unit 11B, and the third filter unit 11C. The filter having the configuration may be the reception filters 17 and 27 or the transmission filter 26. Further, the third filter unit 11C may not be provided.
　（その他の実施の形態など）
　以上、本発明に係る高周波フィルタ素子およびマルチプレクサ（デュプレクサ）について、上記実施の形態を挙げて説明したが、本発明の高周波フィルタ素子およびマルチプレクサは、上記実施の形態に限定されるものではない。上記実施の形態における任意の構成要素を組み合わせて実現される別の実施の形態や、上記実施の形態に対して本発明の主旨を逸脱しない範囲で当業者が思いつく各種変形を施して得られる変形例や、本開示の高周波フィルタ素子を内蔵した各種機器も本発明に含まれる。 (Other embodiments, etc.)
As described above, the high-frequency filter element and the multiplexer (duplexer) according to the present invention have been described with reference to the above embodiment, but the high-frequency filter element and the multiplexer according to the present invention are not limited to the above-described embodiment. Another embodiment realized by combining arbitrary constituent elements in the above-described embodiment, and modifications obtained by applying various modifications conceivable by those skilled in the art to the above-described embodiment without departing from the gist of the present invention. Examples and various devices incorporating the high-frequency filter element of the present disclosure are also included in the present invention.
　例えば、実施の形態では、送信用フィルタ１１が帯域阻止機能を有する第２フィルタ部を備える構成を説明したが、受信用フィルタ１２が第２フィルタ部を備えてもよい。なお、受信帯域よりも送信帯域が低周波側に配置されるシステムにおいて、受信用フィルタ１２が第２フィルタ部を有する場合には、第２フィルタ部を構成する直列共振子の共振周波数および反共振周波数、ならびに、第２フィルタ部を構成する並列共振子の共振周波数および反共振周波数は、送信帯域の低周波帯域外に配される。これにより、受信帯域の低損失性を確保しつつ送信帯域の減衰量を向上させることが可能となる。 For example, in the embodiment, the configuration in which the transmission filter 11 includes the second filter unit having the band rejection function has been described, but the reception filter 12 may include the second filter unit. In the system in which the transmission band is arranged on the lower frequency side than the reception band, when the reception filter 12 has the second filter unit, the resonance frequency and antiresonance of the series resonator that constitutes the second filter unit. The frequency, and the resonance frequency and anti-resonance frequency of the parallel resonator constituting the second filter unit are arranged outside the low frequency band of the transmission band. As a result, it is possible to improve the attenuation of the transmission band while ensuring low loss of the reception band.
　また、上記実施の形態では、送信および受信の双方を担うマルチプレクサ（デュプレクサ）を例示したが、本発明に係る高周波フィルタ素子は、送信のみを担う複数の送信帯域を有する送信装置、および、受信のみを担う複数の受信帯域を有する受信装置にも適用される。 Moreover, in the said embodiment, although the multiplexer (duplexer) which bears both transmission and reception was illustrated, the high frequency filter element which concerns on this invention is a transmission apparatus which has several transmission bands which bear only transmission, and only reception The present invention is also applied to a receiving apparatus having a plurality of receiving bands for carrying
　すなわち、アンテナ素子を介して複数の送信帯域の高周波信号を送信する送信装置であって、送信装置は、第１送信入力端子から入力された高周波信号をフィルタリングして第１送信帯域の高周波信号を、共通端子を経由してアンテナ素子に出力する第１送信側フィルタ回路と、第２送信入力端子から入力された高周波信号をフィルタリングして第１送信帯域と異なる第２送信帯域の高周波信号を、共通端子を経由してアンテナ素子に出力する第２送信側フィルタ回路とを備える。ここで、第１送信側フィルタ回路は、上記実施の形態に係る高周波フィルタ素子を含む。 That is, a transmission device that transmits high-frequency signals in a plurality of transmission bands via an antenna element, the transmission device filtering a high-frequency signal input from a first transmission input terminal to generate a high-frequency signal in the first transmission band. A first transmission-side filter circuit that outputs to the antenna element via the common terminal, and a high-frequency signal in a second transmission band different from the first transmission band by filtering the high-frequency signal input from the second transmission input terminal, And a second transmission filter circuit that outputs to the antenna element via the common terminal. Here, the first transmission filter circuit includes the high-frequency filter element according to the above embodiment.
　これにより、第１送信帯域の低損失性を確保しつつ、第２送信帯域の高減衰および送信側フィルタ回路間の高アイソレーションを達成することが可能となる。 Thereby, it is possible to achieve high attenuation of the second transmission band and high isolation between the transmission side filter circuits while ensuring low loss of the first transmission band.
　また、アンテナ素子を介して複数の受信帯域の高周波信号を受信する受信装置であって、受信装置は、アンテナ素子から共通端子を経由して入力された高周波信号をフィルタリングして第１受信帯域の高周波信号を第１受信出力端子に出力する第１受信側フィルタ回路と、アンテナ素子から共通端子を経由して入力された高周波信号をフィルタリングして第１受信帯域と異なる第２受信帯域の高周波信号を第２受信出力端子に出力する第２受信側フィルタ回路とを備える。ここで、第１受信側フィルタ回路は、上記実施の形態に係る高周波フィルタ素子を含む。 In addition, the receiving device receives high-frequency signals in a plurality of reception bands via an antenna element, and the receiving device filters high-frequency signals input from the antenna element via a common terminal to obtain a first reception band. A first reception-side filter circuit that outputs a high-frequency signal to the first reception output terminal, and a high-frequency signal in a second reception band different from the first reception band by filtering the high-frequency signal input from the antenna element via the common terminal Is provided to the second reception output terminal. Here, the first reception-side filter circuit includes the high-frequency filter element according to the above embodiment.
　これにより、第１受信帯域の低損失性を確保しつつ、第２受信帯域の高減衰および受信側フィルタ回路間の高アイソレーションを達成することが可能となる。 This makes it possible to achieve high attenuation in the second reception band and high isolation between the reception side filter circuits while ensuring low loss in the first reception band.
　また、本発明に係るデュプレクサ１は、上記実施の形態のようなＢａｎｄ８用のデュプレクサに限られず、バンドの選択は任意である。また、マルチプレクサの場合には、バンドの組み合わせは任意である。 Further, the duplexer 1 according to the present invention is not limited to the Band8 duplexer as in the above embodiment, and the selection of the band is arbitrary. In the case of a multiplexer, the combination of bands is arbitrary.
　また、弾性表面波フィルタを構成する圧電基板５１０は、高音速支持基板と、低音速膜と、圧電膜とがこの順で積層された積層構造であってもよい。圧電膜は、例えば、ＬｉＴａＯ３圧電単結晶または圧電セラミックスからなる。圧電膜は、例えば、厚みが６００ｎｍである。高音速支持基板は、低音速膜、圧電膜ならびにＩＤＴ電極５４を支持する基板である。高音速支持基板は、さらに、圧電膜を伝搬する表面波や境界波の弾性波よりも、高音速支持基板中のバルク波の音速が高速となる基板であり、弾性表面波を圧電膜および低音速膜が積層されている部分に閉じ込め、高音速支持基板より下方に漏れないように機能する。高音速支持基板は、例えば、シリコン基板であり、厚みは、例えば２００μｍである。低音速膜は、圧電膜を伝搬するバルク波よりも、低音速膜中のバルク波の音速が低速となる膜であり、圧電膜と高音速支持基板との間に配置される。この構造と、弾性波が本質的に低音速な媒質にエネルギーが集中するという性質とにより、弾性表面波エネルギーのＩＤＴ電極外への漏れが抑制される。低音速膜は、例えば、二酸化ケイ素を主成分とする膜であり、厚みは、例えば６７０ｎｍである。この積層構造によれば、圧電基板５１０を単層で使用している構造と比較して、共振周波数および反共振周波数におけるＱ値を大幅に高めることが可能となる。すなわち、Ｑ値が高い弾性表面波共振子を構成し得るので、当該弾性表面波共振子を用いて、挿入損失が小さいフィルタを構成することが可能となる。 Further, the piezoelectric substrate 510 constituting the surface acoustic wave filter may have a laminated structure in which a high acoustic velocity support substrate, a low acoustic velocity film, and a piezoelectric film are laminated in this order. The piezoelectric film is made of, for example, LiTaO 3 piezoelectric single crystal or piezoelectric ceramic. The piezoelectric film has a thickness of 600 nm, for example. The high sound velocity support substrate is a substrate that supports the low sound velocity film, the piezoelectric film, and the IDT electrode 54. The high-sonic support substrate is a substrate in which the acoustic velocity of the bulk wave in the high-sonic support substrate is higher than that of the surface wave or boundary wave that propagates through the piezoelectric film. It functions in such a way that it is confined in the portion where the sonic film is laminated and does not leak below the high sonic support substrate. The high sound speed support substrate is, for example, a silicon substrate, and has a thickness of, for example, 200 μm. The low acoustic velocity film is a membrane in which the acoustic velocity of the bulk wave in the low acoustic velocity film is lower than the bulk wave propagating through the piezoelectric membrane, and is disposed between the piezoelectric membrane and the high acoustic velocity support substrate. Due to this structure and the property that energy is concentrated in a medium where acoustic waves are essentially low in sound velocity, leakage of surface acoustic wave energy to the outside of the IDT electrode is suppressed. The low acoustic velocity film is, for example, a film mainly composed of silicon dioxide and has a thickness of, for example, 670 nm. According to this laminated structure, the Q value at the resonance frequency and the anti-resonance frequency can be significantly increased as compared with a structure in which the piezoelectric substrate 510 is used as a single layer. That is, since a surface acoustic wave resonator having a high Q value can be configured, a filter with a small insertion loss can be configured using the surface acoustic wave resonator.
　なお、高音速支持基板は、支持基板と、圧電膜を伝搬する表面波や境界波の弾性波よりも、伝搬するバルク波の音速が高速となる高音速膜とが積層された構造を有していてもよい。この場合、支持基板は、サファイア、リチウムタンタレート、リチウムニオベイト、水晶等の圧電体、アルミナ、マグネシア、窒化ケイ素、窒化アルミニウム、炭化ケイ素、ジルコニア、コージライト、ムライト、ステアタイト、フォルステライト等の各種セラミック、ガラス等の誘電体またはシリコン、窒化ガリウム等の半導体及び樹脂基板等を用いることができる。また、高音速膜は、窒化アルミニウム、酸化アルミニウム、炭化ケイ素、窒化ケイ素、酸窒化ケイ素、ＤＬＣ膜またはダイヤモンド、上記材料を主成分とする媒質、上記材料の混合物を主成分とする媒質等、様々な高音速材料を用いることができる。 Note that the high sound velocity support substrate has a structure in which a support substrate and a high sound velocity film in which the velocity of the bulk wave propagating is higher than that of the surface wave and boundary wave propagating in the piezoelectric film are stacked. It may be. In this case, the support substrate is a piezoelectric material such as sapphire, lithium tantalate, lithium niobate, crystal, alumina, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mullite, steatite, forsterite, etc. Various ceramics, dielectrics such as glass, semiconductors such as silicon and gallium nitride, resin substrates, and the like can be used. In addition, the high sound velocity film includes various materials such as aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, DLC film or diamond, a medium mainly composed of the above materials, and a medium mainly composed of a mixture of the above materials. High sound velocity material can be used.
　本発明は、マルチバンド化およびマルチモード化された周波数規格に適用できる帯域内低損失かつ帯域外高減衰を有する高周波フィルタ、マルチプレクサ、送信装置および受信装置として、携帯電話などの通信機器に広く利用できる。 INDUSTRIAL APPLICABILITY The present invention is widely used in communication devices such as mobile phones as high-frequency filters, multiplexers, transmitters, and receivers that have low in-band loss and high out-of-band attenuation that can be applied to multiband and multimode frequency standards. it can.
　１、１Ａ、１Ｂ　　デュプレクサ
　２　　アンテナ素子
　３　　アンテナ整合回路
　４　　クワッドプレクサ
　１０、４１、５１　　送信入力端子
　１１、１６、２６、４１１　　送信用フィルタ
　１１Ａ　　第１フィルタ部
　１１Ｂ　　第２フィルタ部
　１１Ｃ　　第３フィルタ部
　１２、１７、２７　　受信用フィルタ
　１３、２３　　整合回路
　１４、２４　　フィルタ入力端子
　２０、４２、５２　　受信出力端子
　３０　　共通端子
　５４、１０１ａ、１０１ｂ、　　ＩＤＴ電極
　１０１、１０２、１０３、１０４、１０５、４０１、４０２、４０３、４０４　　直列共振子
　１１０ａ、１１０ｂ　　電極指
　１１１ａ、１１１ｂ　　バスバー電極
　１３１　　インダクタ
　１３２　　キャパシタ
　１５１、１５２、１５３、１５４、４５１、４５２、４５３　　並列共振子
　５１０　　圧電基板
　５４１　　密着層
　５４２　　主電極層
　５５０　　保護層 1, 1A, 1B Duplexer 2 Antenna element 3 Antenna matching circuit 4 Quadplexer 10, 41, 51 Transmission input terminal 11, 16, 26, 411 Transmission filter 11A First filter unit 11B Second filter unit 11C Third filter unit 12, 17, 27 Reception filter 13, 23 Matching circuit 14, 24 Filter input terminal 20, 42, 52 Reception output terminal 30 Common terminal 54, 101a, 101b, IDT electrode 101, 102, 103, 104, 105, 401, 402, 403, 404 Series resonator 110a, 110b Electrode finger 111a, 111b Bus bar electrode 131 Inductor 132 Capacitor 151, 152, 153, 154, 451, 452, 453 Parallel resonator 510 Piezoelectric substrate 541 Adhesion layer 542 Main power Layer 550 protective layer

Claims (13)

  1. 　高周波信号を入力または出力する第１端子および第２端子と、
    　前記第１端子に接続され、第１周波数帯域の高周波信号を選択的に通過させる特性を有する第１フィルタ部と、
    　前記第２端子と前記第１フィルタ部との間に接続され、前記第１周波数帯域と異なる第２周波数帯域の高周波信号を選択的に減衰させる特性を有する第２フィルタ部と、を備え、
    　前記第２フィルタ部は、
    　前記第１フィルタ部と前記第２端子との間に接続された直列共振子と、
    　前記第１フィルタ部から前記第２端子までの接続経路と基準端子との間に接続された並列共振子と、を有し、
    　前記並列共振子の反共振周波数は、前記第１周波数帯域の帯域外に配され、
    　前記直列共振子の共振周波数は前記並列共振子の反共振周波数よりも低く、前記直列共振子の共振周波数と前記並列共振子の反共振周波数との間に、前記直列共振子の反共振周波数および前記並列共振子の共振周波数が配されている、
    　高周波フィルタ素子。     A first terminal and a second terminal for inputting or outputting a high-frequency signal;
    A first filter unit connected to the first terminal and having a characteristic of selectively passing a high-frequency signal in a first frequency band;
    A second filter unit connected between the second terminal and the first filter unit and having a characteristic of selectively attenuating a high-frequency signal in a second frequency band different from the first frequency band;
    The second filter unit is
    A series resonator connected between the first filter unit and the second terminal;
    A parallel resonator connected between a connection path from the first filter unit to the second terminal and a reference terminal;
    The antiresonance frequency of the parallel resonator is arranged outside the first frequency band,
    The resonance frequency of the series resonator is lower than the anti-resonance frequency of the parallel resonator, and between the resonance frequency of the series resonator and the anti-resonance frequency of the parallel resonator, The resonance frequency of the parallel resonator is arranged,
    High frequency filter element.
  2. 　前記直列共振子の反共振周波数および前記並列共振子の共振周波数は、前記第２周波数帯域に配されている、
    　請求項１に記載の高周波フィルタ素子。     The antiresonance frequency of the series resonator and the resonance frequency of the parallel resonator are arranged in the second frequency band,
    The high frequency filter element according to claim 1.
  3. 　さらに、
    　前記第２端子に接続されたインピーダンス整合回路を備える、
    　請求項１または２に記載の高周波フィルタ素子。     further,
    An impedance matching circuit connected to the second terminal;
    The high frequency filter element according to claim 1 or 2.
  4. 　前記第１フィルタ部および前記第２フィルタ部のそれぞれは、ＳＡＷ（Ｓｕｒｆａｃｅ　Ａｃｏｕｓｔｉｃ　Ｗａｖｅ）、または、ＢＡＷ（Ｂｕｌｋ　Ａｃｏｕｓｔｉｃ　Ｗａｖｅ）を用いた弾性波共振子で構成されている、
    　請求項１～３のいずれか１項に記載の高周波フィルタ素子。     Each of the first filter unit and the second filter unit is composed of an acoustic wave resonator using SAW (Surface Acoustic Wave) or BAW (Bulk Acoustic Wave).
    The high-frequency filter element according to any one of claims 1 to 3.
  5. 　前記第１フィルタ部および前記第２フィルタ部は、１枚の圧電基板上に形成されている、
    　請求項４に記載の高周波フィルタ素子。     The first filter part and the second filter part are formed on one piezoelectric substrate,
    The high frequency filter element according to claim 4.
  6. 　前記第１フィルタ部および前記第２フィルタ部は、１チップ化されている、
    　請求項１～５のいずれか１項に記載の高周波フィルタ素子。     The first filter unit and the second filter unit are made into one chip.
    The high-frequency filter element according to any one of claims 1 to 5.
  7. 　送信入力端子から入力された高周波信号をフィルタリングして送信帯域の高周波信号を、共通端子に出力する送信側フィルタ回路と、
    　前記共通端子から入力された高周波信号をフィルタリングして受信帯域の高周波信号を受信出力端子に出力する受信側フィルタ回路と、を備えるマルチプレクサであって、
    　前記送信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、
    　前記送信帯域は、前記第１周波数帯域であり、
    　前記受信帯域は、前記第２周波数帯域である、
    　マルチプレクサ。     A transmission-side filter circuit that filters a high-frequency signal input from a transmission input terminal and outputs a high-frequency signal in a transmission band to a common terminal;
    A reception-side filter circuit that filters a high-frequency signal input from the common terminal and outputs a high-frequency signal in a reception band to a reception output terminal;
    The transmission filter circuit includes the high-frequency filter element according to any one of claims 1 to 6,
    The transmission band is the first frequency band;
    The reception band is the second frequency band.
    Multiplexer.
  8. 　送信入力端子から入力された高周波信号をフィルタリングして送信帯域の高周波信号を、共通端子に出力する送信側フィルタ回路と、
    　前記共通端子から入力された高周波信号をフィルタリングして受信帯域の高周波信号を受信出力端子に出力する受信側フィルタ回路と、を備えるマルチプレクサであって、
    　前記受信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、
    　前記送信帯域は、前記第２周波数帯域であり、
    　前記受信帯域は、前記第１周波数帯域である、
    　マルチプレクサ。     A transmission-side filter circuit that filters a high-frequency signal input from a transmission input terminal and outputs a high-frequency signal in a transmission band to a common terminal;
    A reception-side filter circuit that filters a high-frequency signal input from the common terminal and outputs a high-frequency signal in a reception band to a reception output terminal;
    The reception-side filter circuit includes the high-frequency filter element according to any one of claims 1 to 6,
    The transmission band is the second frequency band;
    The reception band is the first frequency band.
    Multiplexer.
  9. 　前記第２端子は、前記共通端子であり、
    　前記インピーダンス整合回路は、前記共通端子と前記第２フィルタ部との間に接続されている、
    　請求項７または８に記載のマルチプレクサ。     The second terminal is the common terminal;
    The impedance matching circuit is connected between the common terminal and the second filter unit.
    The multiplexer according to claim 7 or 8.
  10. 　前記第２端子は、前記送信入力端子または前記受信出力端子であり、
    　前記インピーダンス整合回路は、前記送信入力端子または前記受信出力端子と前記第２フィルタ部との間に接続されている、
    　請求項７または８に記載のマルチプレクサ。     The second terminal is the transmission input terminal or the reception output terminal;
    The impedance matching circuit is connected between the transmission input terminal or the reception output terminal and the second filter unit.
    The multiplexer according to claim 7 or 8.
  11. 　第１デュプレクサおよび第２デュプレクサを備えるマルチプレクサであって、
    　前記第１デュプレクサは、
    　第１送信入力端子から入力された高周波信号をフィルタリングして第１送信帯域の高周波信号を、共通端子を経由してアンテナ素子に出力する第１送信側フィルタ回路と、
    　前記アンテナ素子から前記共通端子を経由して入力された高周波信号をフィルタリングして前記第１送信帯域と異なる第１受信帯域の高周波信号を第１受信出力端子に出力する第１受信側フィルタ回路と、を備え、
    　前記第２デュプレクサは、
    　第２送信入力端子から入力された高周波信号をフィルタリングして前記第１送信帯域および前記第１受信帯域と異なる第２送信帯域の高周波信号を、前記共通端子を経由して前記アンテナ素子に出力する第２送信側フィルタ回路と、
    　前記アンテナ素子から前記共通端子を経由して入力された高周波信号をフィルタリングして前記第１送信帯域、前記第１受信帯域および前記第２送信帯域と異なる第２受信帯域の高周波信号を第２受信出力端子に出力する第２受信側フィルタ回路と、を備え、
    　前記第１送信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、
    　前記第１送信帯域は、前記第１周波数帯域であり、
    　前記第２受信帯域は、前記第２周波数帯域である、
    　マルチプレクサ。     A multiplexer comprising a first duplexer and a second duplexer,
    The first duplexer is:
    A first transmission-side filter circuit that filters a high-frequency signal input from a first transmission input terminal and outputs a high-frequency signal in a first transmission band to an antenna element via a common terminal;
    A first reception-side filter circuit that filters a high-frequency signal input from the antenna element via the common terminal and outputs a high-frequency signal in a first reception band different from the first transmission band to a first reception output terminal; With
    The second duplexer is:
    A high-frequency signal input from the second transmission input terminal is filtered to output a high-frequency signal in a second transmission band different from the first transmission band and the first reception band to the antenna element via the common terminal. A second transmission filter circuit;
    A high-frequency signal input from the antenna element via the common terminal is filtered to receive a high-frequency signal in a second reception band different from the first transmission band, the first reception band, and the second transmission band. A second receiving-side filter circuit that outputs to an output terminal,
    The first transmission filter circuit includes the high frequency filter element according to any one of claims 1 to 6,
    The first transmission band is the first frequency band;
    The second reception band is the second frequency band.
    Multiplexer.
  12. 　アンテナ素子を介して複数の送信帯域の高周波信号を送信する送信装置であって、
    　前記送信装置は、
    　第１送信入力端子から入力された高周波信号をフィルタリングして第１送信帯域の高周波信号を、共通端子を経由してアンテナ素子に出力する第１送信側フィルタ回路と、
    　第２送信入力端子から入力された高周波信号をフィルタリングして前記第１送信帯域と異なる第２送信帯域の高周波信号を、前記共通端子を経由して前記アンテナ素子に出力する第２送信側フィルタ回路と、を備え、
    　前記第１送信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、
    　前記第１送信帯域は、前記第１周波数帯域であり、
    　前記第２送信帯域は、前記第２周波数帯域である、
    　送信装置。     A transmission device that transmits high-frequency signals of a plurality of transmission bands via an antenna element,
    The transmitter is
    A first transmission-side filter circuit that filters a high-frequency signal input from a first transmission input terminal and outputs a high-frequency signal in a first transmission band to an antenna element via a common terminal;
    A second transmission-side filter circuit that filters a high-frequency signal input from a second transmission input terminal and outputs a high-frequency signal in a second transmission band different from the first transmission band to the antenna element via the common terminal And comprising
    The first transmission filter circuit includes the high frequency filter element according to any one of claims 1 to 6,
    The first transmission band is the first frequency band;
    The second transmission band is the second frequency band;
    Transmitter device.
  13. 　アンテナ素子を介して複数の受信帯域の高周波信号を受信する受信装置であって、
    　前記受信装置は、
    　前記アンテナ素子から共通端子を経由して入力された高周波信号をフィルタリングして第１受信帯域の高周波信号を第１受信出力端子に出力する第１受信側フィルタ回路と、
    　前記アンテナ素子から前記共通端子を経由して入力された高周波信号をフィルタリングして第１受信帯域と異なる第２受信帯域の高周波信号を第２受信出力端子に出力する第２受信側フィルタ回路と、を備え、
    　前記第１受信側フィルタ回路は、請求項１～６のいずれか１項に記載の高周波フィルタ素子を含み、
    　前記第１受信帯域は、前記第１周波数帯域であり、
    　前記第２受信帯域は、前記第２周波数帯域である、
    　受信装置。     A receiving device for receiving high-frequency signals in a plurality of reception bands via an antenna element,
    The receiving device is:
    A first reception-side filter circuit that filters a high-frequency signal input from the antenna element via a common terminal and outputs a high-frequency signal in a first reception band to a first reception output terminal;
    A second reception-side filter circuit that filters a high-frequency signal input from the antenna element via the common terminal and outputs a high-frequency signal in a second reception band different from the first reception band to a second reception output terminal; With
    The first reception-side filter circuit includes the high-frequency filter element according to any one of claims 1 to 6,
    The first reception band is the first frequency band;
    The second reception band is the second frequency band.
    Receiver device.
PCT/JP2017/010814 2016-03-18 2017-03-16 High-frequency filter element, multiplexer, transmitter, and receiver WO2017159834A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016055873 2016-03-18
JP2016-055873 2016-03-18

Publications (1)

Publication Number Publication Date
WO2017159834A1 true WO2017159834A1 (en) 2017-09-21

Family

ID=59851067

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/010814 WO2017159834A1 (en) 2016-03-18 2017-03-16 High-frequency filter element, multiplexer, transmitter, and receiver

Country Status (1)

Country Link
WO (1) WO2017159834A1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018139598A1 (en) * 2017-01-30 2018-08-02 京セラ株式会社 Surface acoustic wave filter, demultiplexer, and communication device
JP2019096971A (en) * 2017-11-20 2019-06-20 株式会社村田製作所 High frequency filter and multiplexer
WO2019131501A1 (en) * 2017-12-25 2019-07-04 株式会社村田製作所 Multiplexer
CN110365307A (en) * 2018-03-26 2019-10-22 株式会社村田制作所 Multiplexer
WO2019235490A1 (en) * 2018-06-05 2019-12-12 株式会社村田製作所 Multiplexer
CN111108689A (en) * 2017-09-29 2020-05-05 株式会社村田制作所 Multiplexer, high-frequency front-end circuit and communication device
CN111164888A (en) * 2017-09-29 2020-05-15 株式会社村田制作所 Multiplexer, high-frequency front-end circuit and communication device
CN113196658A (en) * 2018-12-20 2021-07-30 株式会社村田制作所 Multiplexer
CN114051695A (en) * 2019-07-03 2022-02-15 株式会社村田制作所 High-frequency module and communication device
CN114144976A (en) * 2019-07-03 2022-03-04 株式会社村田制作所 High-frequency module and communication device
WO2022091582A1 (en) * 2020-10-28 2022-05-05 株式会社村田製作所 Elastic wave filter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07154200A (en) * 1993-11-26 1995-06-16 Oki Electric Ind Co Ltd Resonator surface acoustic wave filter
JP2008301223A (en) * 2007-05-31 2008-12-11 Panasonic Corp High frequency filter
WO2013046892A1 (en) * 2011-09-30 2013-04-04 株式会社村田製作所 Branching device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07154200A (en) * 1993-11-26 1995-06-16 Oki Electric Ind Co Ltd Resonator surface acoustic wave filter
JP2008301223A (en) * 2007-05-31 2008-12-11 Panasonic Corp High frequency filter
WO2013046892A1 (en) * 2011-09-30 2013-04-04 株式会社村田製作所 Branching device

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2018139598A1 (en) * 2017-01-30 2019-02-07 京セラ株式会社 Elastic wave filter, duplexer, and communication device
US11309867B2 (en) 2017-01-30 2022-04-19 Kyocera Corporation Acoustic wave filter, multiplexer, and communication apparatus
WO2018139598A1 (en) * 2017-01-30 2018-08-02 京セラ株式会社 Surface acoustic wave filter, demultiplexer, and communication device
CN111108689B (en) * 2017-09-29 2023-09-26 株式会社村田制作所 Multiplexer, high-frequency front-end circuit, and communication device
CN111164888B (en) * 2017-09-29 2023-09-12 株式会社村田制作所 Multiplexer, high-frequency front-end circuit, and communication device
CN111108689A (en) * 2017-09-29 2020-05-05 株式会社村田制作所 Multiplexer, high-frequency front-end circuit and communication device
CN111164888A (en) * 2017-09-29 2020-05-15 株式会社村田制作所 Multiplexer, high-frequency front-end circuit and communication device
US10763824B2 (en) 2017-11-20 2020-09-01 Murata Manufacturing Co., Ltd. High-frequency filter and multiplexer
JP2019096971A (en) * 2017-11-20 2019-06-20 株式会社村田製作所 High frequency filter and multiplexer
DE102018129076B4 (en) 2017-11-20 2022-03-24 Murata Manufacturing Co., Ltd. High frequency filter and multiplexer
WO2019131501A1 (en) * 2017-12-25 2019-07-04 株式会社村田製作所 Multiplexer
CN111527700B (en) * 2017-12-25 2023-09-05 株式会社村田制作所 multiplexer
CN111527700A (en) * 2017-12-25 2020-08-11 株式会社村田制作所 Multiplexer
JPWO2019131501A1 (en) * 2017-12-25 2020-08-06 株式会社村田製作所 Multiplexer
CN110365307B (en) * 2018-03-26 2023-02-28 株式会社村田制作所 Multiplexer
CN110365307A (en) * 2018-03-26 2019-10-22 株式会社村田制作所 Multiplexer
JPWO2019235490A1 (en) * 2018-06-05 2021-02-12 株式会社村田製作所 Multiplexer
WO2019235490A1 (en) * 2018-06-05 2019-12-12 株式会社村田製作所 Multiplexer
US11929726B2 (en) 2018-06-05 2024-03-12 Murata Manufacturing Co., Ltd. Multiplexer
CN113196658A (en) * 2018-12-20 2021-07-30 株式会社村田制作所 Multiplexer
CN113196658B (en) * 2018-12-20 2024-05-03 株式会社村田制作所 Multiplexer
CN114144976A (en) * 2019-07-03 2022-03-04 株式会社村田制作所 High-frequency module and communication device
CN114051695A (en) * 2019-07-03 2022-02-15 株式会社村田制作所 High-frequency module and communication device
CN114051695B (en) * 2019-07-03 2023-08-18 株式会社村田制作所 High frequency module and communication device
CN114144976B (en) * 2019-07-03 2023-08-25 株式会社村田制作所 High frequency module and communication device
WO2022091582A1 (en) * 2020-10-28 2022-05-05 株式会社村田製作所 Elastic wave filter

Similar Documents

Publication Publication Date Title
US11394369B2 (en) Multiplexer, transmission device, reception device, high-frequency front end circuit, communication device and impedance matching method for multiplexer
US10644674B2 (en) Multiplexer, radio-frequency front-end circuit, and communication device
US10382009B2 (en) Radio frequency front-end circuit and communication device
KR102429897B1 (en) Multiplexers, high-frequency front-end circuits and communication devices
CN109286384B (en) Multiplexer, high-frequency front-end circuit, and communication device
CN107710614B (en) Elastic wave filter, multiplexer, duplexer, high-frequency front-end circuit, and communication device
WO2017159834A1 (en) High-frequency filter element, multiplexer, transmitter, and receiver
JP6790907B2 (en) Multiplexer, transmitter and receiver
CN109478880B (en) Multiplexer, high-frequency front-end circuit and communication device
US9860006B1 (en) Multiplexer, high-frequency front-end circuit, and communication device
KR102153878B1 (en) Multiplexers, high frequency front-end circuits and communication devices
JP2018137655A5 (en)
KR20200051541A (en) Multiplexer
JP2017152881A (en) Multiplexer, transmission device and reception device
CN109417380B (en) Multiplexer, high-frequency front-end circuit and communication device
CN111512548B (en) Elastic wave filter, multiplexer, high-frequency front-end circuit, and communication device
WO2018212047A1 (en) Multiplexer, high-frequency front-end circuit and communication device
KR20200139228A (en) Multiplexer, high frequency front-end circuit and communication device
CN112640304B (en) Filter device and multiplexer
JP2019004364A (en) Elastic wave filter and multiplexer
JP2020048067A (en) Extractor
WO2018212105A1 (en) Multiplexer, transmission device and reception device
WO2018003837A1 (en) Multiplexer and method for manufacturing same

Legal Events

Date Code Title Description
NENP Non-entry into the national phase

Ref country code: DE

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17766829

Country of ref document: EP

Kind code of ref document: A1

122 Ep: pct application non-entry in european phase

Ref document number: 17766829

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP