WO2021157402A1 - Antenna matching circuit - Google Patents

Antenna matching circuit Download PDF

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Publication number
WO2021157402A1
WO2021157402A1 PCT/JP2021/002410 JP2021002410W WO2021157402A1 WO 2021157402 A1 WO2021157402 A1 WO 2021157402A1 JP 2021002410 W JP2021002410 W JP 2021002410W WO 2021157402 A1 WO2021157402 A1 WO 2021157402A1
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Prior art keywords
terminal
inductor
matching circuit
antenna matching
connection state
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PCT/JP2021/002410
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French (fr)
Japanese (ja)
Inventor
喜代美 池本
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株式会社村田製作所
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Publication of WO2021157402A1 publication Critical patent/WO2021157402A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
    • 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

Definitions

  • the present invention relates to an antenna matching circuit.
  • the antenna matching circuit is provided to match the impedance between the antenna and the feeding circuit.
  • the antenna matching circuit is composed of, for example, a combination of a plurality of inductors and a plurality of capacitors. The combination of multiple inductors and multiple capacitors is adjusted according to the required frequency and antenna characteristics.
  • Patent Document 1 describes a variable inductor capable of changing the inductance value.
  • Patent Document 2 describes an antenna device using a variable inductor.
  • a variable inductor is configured by utilizing the coupling of inductors.
  • each terminal of a plurality of inductors is connected to any one of a ground, a capacitor, a resistance element, and the like. Therefore, in the antenna matching circuit using the variable inductors of Patent Documents 1 and 2, when matching at a plurality of frequencies with one antenna, the number of parts connected to the plurality of inductors increases. Therefore, a large area for mounting the components is required, and the number of wirings connecting them may increase.
  • An object of the present invention is to provide an antenna matching circuit capable of matching at a plurality of frequencies and being miniaturized.
  • the antenna matching circuit on one aspect of the present invention includes an antenna, a first inductor connected to the antenna, a second inductor that forms a mutual inductance between the first inductor, the first inductor, and the first inductor. It has a plurality of terminals electrically connected to both ends of each of the two inductors, at least two of the terminals, and a switch for switching the connection state with the first reference potential. Of the terminals, the terminal that is not connected to the first reference potential is in an open state.
  • the antenna matching circuit of the present invention matching at a plurality of frequencies can be achieved and miniaturization is possible.
  • FIG. 1 is a circuit diagram schematically showing an antenna matching circuit according to the first embodiment.
  • FIG. 2 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the first embodiment.
  • FIG. 3 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the first embodiment.
  • FIG. 4 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the first embodiment.
  • FIG. 5 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the first embodiment.
  • FIG. 6 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the first embodiment.
  • FIG. 7 is a circuit diagram schematically showing an antenna matching circuit according to the second embodiment.
  • FIG. 8 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 9 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 10 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 11 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 12 is an equivalent circuit diagram schematically showing a fifth connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 13 is an equivalent circuit diagram schematically showing a sixth connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 14 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the second embodiment.
  • FIG. 15 is a circuit diagram schematically showing an antenna matching circuit according to a third embodiment.
  • FIG. 16 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 17 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 18 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 19 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 1 is a circuit diagram schematically showing an antenna matching circuit according to the first embodiment.
  • the antenna matching circuit 1 includes an antenna 10, a common mode choke coil 20, a switch 30, and a control circuit 40.
  • the antenna matching circuit 1 is a circuit for performing impedance matching of the antenna 10.
  • the antenna 10 is mounted on, for example, a mobile terminal such as a mobile phone, a smartphone or a tablet terminal, a personal computer having a communication function, or the like.
  • the antenna 10 transmits and receives a signal in a frequency band of 0.6 GHz or more and 6 GHz or less.
  • the common mode choke coil 20 has a first inductor 21 and a second inductor 22 that are magnetically coupled to each other. That is, a mutual inductance is formed between the first inductor 21 and the second inductor 22.
  • the first inductor 21 is connected to the antenna 10. Specifically, one end of the first inductor 21 is electrically connected to the first terminal T1, and the other end is electrically connected to the second terminal T2. The first inductor 21 is electrically connected to the antenna 10 via the first terminal T1. Further, one end side of the second inductor 22 is electrically connected to the third terminal T3, and the other end side is electrically connected to the fourth terminal T4.
  • the common mode choke coil 20 of this embodiment has four terminals. However, the present invention is not limited to this, and the common mode choke coil 20 may have five or more terminals.
  • the common mode choke coil 20 may have any configuration, but for example, it is desirable that the first inductor 21 and the second inductor 22 are integrated common mode choke coils 20.
  • the integrated type has, for example, a configuration in which a coil forming the first inductor 21 and a coil forming the second inductor 22 are wound around a common core (for example, a ferrite core) made of a magnetic material.
  • the common mode choke coil 20 is not limited to the integrated type, and may have a configuration in which each inductor is magnetically coupled.
  • each inductor may be formed in an individual divided core, or may be composed of a flat coil.
  • the switch 30 is an element that switches the connection state between at least two terminals of the plurality of terminals (first terminal T1 to fourth terminal T4) of the common mode choke coil 20 and the first reference potential 50.
  • the switch 30 has switch-side terminals TS1, TS2, TS3, and TS4 provided corresponding to the first terminal T1 to the fourth terminal T4, respectively.
  • the switch 30 connects one of the switch-side terminals TS1, TS2, TS3, and TS4 to the first reference potential 50 based on the control signal Si supplied from the control circuit 40.
  • one of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30.
  • the terminal that is not connected to the first reference potential 50 is in the open state. That is, the switch-side terminal that is not connected to the first reference potential 50 is not connected to any other wiring, element, or the like. As a result, due to the operation of the switch 30, the terminal of the first terminal T1 to the fourth terminal T4 that is not connected to the first reference potential 50 is opened.
  • the switch 30 is, for example, a semiconductor switch.
  • the semiconductor switch is, for example, a FET (Field Effect Transistor).
  • the control circuit 40 is configured as, for example, an IC (Integrated Circuit).
  • the control circuit 40 may be included in an RFIC (Radio Frequency Integrated Circuit) that controls transmission / reception of the antenna 10.
  • the first reference potential 50 may be a fixed potential, for example, a ground potential. Specifically, the first reference potential 50 is the ground of the substrate on which the antenna matching circuit 1 is mounted or the ground of the housing.
  • FIG. 2 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the first embodiment.
  • the first terminal T1 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30.
  • the second terminal T2, the third terminal T3, and the fourth terminal T4, which are not connected to the first reference potential 50 are in an open state.
  • the second terminal T2, the third terminal T3, and the fourth terminal T4 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the second terminal T2, the third terminal T3, and the fourth terminal T4 are equivalently capacitively connected and function as a circuit.
  • the parasitic capacitance Cs is a capacitance component formed between the coil forming the first inductor 21 and the second inductor 22 and another conductor.
  • Other conductors are, for example, electrodes and wiring provided on a substrate on which the common mode choke coil 20 is mounted, or parts and housings of a communication device in which the antenna matching circuit 1 is incorporated.
  • the second reference potential 51 may be a ground having the same potential as the first reference potential 50, or may be a potential different from the first reference potential 50.
  • FIG. 3 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the first embodiment.
  • the second terminal T2 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30.
  • the first terminal T1, the third terminal T3, and the fourth terminal T4, which are not connected to the first reference potential 50 are in an open state.
  • the first terminal T1, the third terminal T3, and the fourth terminal T4 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the first terminal T1, the third terminal T3, and the fourth terminal T4 are equivalently capacitively connected and function as a circuit.
  • FIG. 4 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the first embodiment.
  • the third terminal T3 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30.
  • the first terminal T1, the second terminal T2, and the fourth terminal T4 which are not connected to the first reference potential 50, are in an open state.
  • the first terminal T1, the second terminal T2 and the fourth terminal T4 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the first terminal T1, the second terminal T2, and the fourth terminal T4 are equivalently capacitively connected and function as a circuit.
  • FIG. 5 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the first embodiment.
  • the fourth terminal T4 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30.
  • the first terminal T1, the second terminal T2, and the third terminal T3, which are not connected to the first reference potential 50 are in an open state.
  • the first terminal T1, the second terminal T2 and the third terminal T3 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the first terminal T1, the second terminal T2, and the third terminal T3 are equivalently capacitively connected and function as a circuit.
  • the antenna matching circuit 1 has a plurality of terminals of the first inductor 21 and the second inductor 22 and a first reference by the operation of the switch 30 according to the frequency and characteristics of the antenna 10.
  • the connection state with the potential 50 can be switched.
  • the antenna matching circuit 1 can be switched to four types of connection states by one common mode choke coil 20.
  • the coupling state (direction of the magnetic field) between the first inductor 21 and the second inductor 22 of the common mode choke coil 20 changes.
  • the antenna matching circuit 1 can change the impedance by utilizing the mutual inductance of the common mode and the differential mode.
  • the terminals in the unconnected state are in the open state, and there is no need to connect them to elements (capacitors, inductors, etc.) for changing impedance. Further, the terminals in the unconnected state are equivalently connected to the second reference potential 51 via the parasitic capacitance Cs. That is, it is not necessary to provide wiring or the like for connecting the terminal in the non-connected state and the second reference potential 51. Therefore, the antenna matching circuit 1 can be miniaturized.
  • FIG. 6 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the first embodiment.
  • the vertical axis shows S11 (reflection coefficient) of the S parameter
  • the horizontal axis shows the frequency.
  • the resonance frequency is different in each of the first connection state M1 to the fourth connection state M4.
  • the resonance frequencies of the antenna matching circuit 1 are around 9 GHz and 11 GHz.
  • the resonance frequency of the antenna matching circuit 1 is around 10 GHz.
  • the resonance frequency of the antenna matching circuit 1 is around 9 GHz.
  • the resonance frequency of the antenna matching circuit 1 is around 3 GHz.
  • the resonance frequency of the antenna matching circuit 1 can be changed by switching the connection state of the first inductor 21, the second inductor 22, and the first reference potential 50.
  • the antenna matching circuit 1 can realize a plurality of different antenna characteristics with one common mode choke coil 20.
  • the antenna matching circuit 1 may be provided with a capacitor element, an inductor element, a resistance element, etc., depending on the characteristics required for the antenna 10, or a filter, an amplifier, or the like used for transmission / reception of the antenna 10 is connected. You may be.
  • the present invention is not limited to this. That is, the switch 30 can perform impedance matching as long as the connection state of at least two of the four terminals can be switched. In this case, one or two of the four terminals can be left open without being connected to the first reference potential 50 in any of the connected states. In other words, the antenna matching circuit 1 only needs to be able to switch at least two connection states from the first connection state M1 to the fourth connection state M4.
  • the antenna matching circuit 1 of the present embodiment includes the antenna 10, the first inductor 21 connected to the antenna 10, and the second inductor 22 that forms a mutual inductance between the first inductor 21.
  • a plurality of terminals (first terminal T1 to fourth terminal T4) electrically connected to both ends of the first inductor 21 and the second inductor 22, at least two of the plurality of terminals, and a first terminal. It has a switch 30 for switching the connection state with the reference potential 50. Of the plurality of terminals, the terminal that is not connected to the first reference potential 50 is in the open state.
  • FIG. 7 is a circuit diagram schematically showing an antenna matching circuit according to the second embodiment.
  • the common mode choke coil 20A further includes the third inductor 23 will be described.
  • the common mode choke coil 20A of the antenna matching circuit 1A further has a third inductor 23 and two terminals (fifth) electrically connected to both ends of the third inductor 23. It has a terminal T5 and a sixth terminal T6).
  • the third inductor 23 forms a mutual inductance with at least one of the first inductor 21 and the second inductor 22.
  • the third inductor 23 of the present embodiment is formed as a common mode choke coil 20A integrated with the first inductor 21 and the second inductor 22. That is, the common mode choke coil 20A is configured by winding the coils forming the first inductor 21, the second inductor 22, and the third inductor 23 around a common core.
  • the switch 30A has switch-side terminals TS1, TS2, TS3, TS4, TS5, and TS6 provided corresponding to the first terminal T1 to the sixth terminal T6, respectively.
  • the switch 30A connects one of the switch-side terminals TS1, TS2, TS3, TS4, TS5, and TS6 with the first reference potential 50 based on the control signal Si supplied from the control circuit 40. ..
  • one of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the switch 30A of the present embodiment switches the connection state between the six terminals including the two terminals (fifth terminal T5 and sixth terminal T6) of the third inductor 23 and the first reference potential 50.
  • the terminal that is not connected to the first reference potential 50 is in the open state. That is, by the operation of the switch 30A, the terminal of the first terminal T1 to the sixth terminal T6 that is not connected to the first reference potential 50 is opened.
  • FIG. 8 is an equivalent circuit diagram schematically showing the first connection state of the antenna matching circuit according to the second embodiment.
  • the first terminal T1 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the second terminal T2 to the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state.
  • the second terminal T2 to the sixth terminal T6 are connected to the second reference potential 51 via the parasitic capacitance Cs, respectively.
  • the second terminal T2 to the sixth terminal T6 are equivalently connected by capacitance and function as a circuit.
  • FIG. 9 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the second embodiment.
  • the second terminal T2 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the first terminal T1 and the third terminal T3 to the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state.
  • the first terminal T1 and the third terminal T3 to the sixth terminal T6 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the first terminal T1 and the third terminal T3 to the sixth terminal T6 are equivalently connected by capacitance and function as a circuit.
  • FIG. 10 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the second embodiment.
  • the third terminal T3 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the first terminal T1, the second terminal T2, the fourth terminal T4, the fifth terminal T5, and the sixth terminal T6, which are not connected to the first reference potential 50 are It is in an open state.
  • the first terminal T1, the second terminal T2, the fourth terminal T4, the fifth terminal T5, and the sixth terminal T6 are respectively via the parasitic capacitance Cs. It is connected to the second reference potential 51.
  • the first terminal T1, the second terminal T2, the fourth terminal T4, the fifth terminal T5, and the sixth terminal T6 are equally capacitively connected and function as a circuit.
  • FIG. 11 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the second embodiment.
  • the fourth terminal T4 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the first terminal T1, the second terminal T2, the third terminal T3, the fifth terminal T5, and the sixth terminal T6, which are not connected to the first reference potential 50 are It is in an open state.
  • the first terminal T1, the second terminal T2, the third terminal T3, the fifth terminal T5, and the sixth terminal T6 are respectively via the parasitic capacitance Cs. It is connected to the second reference potential 51.
  • the first terminal T1, the second terminal T2, the third terminal T3, the fifth terminal T5, and the sixth terminal T6 are equally capacitively connected and function as a circuit.
  • FIG. 12 is an equivalent circuit diagram schematically showing a fifth connection state of the antenna matching circuit according to the second embodiment.
  • the fifth terminal T5 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the first terminal T1 to the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state.
  • the first terminal T1 to the fourth terminal T4 and the sixth terminal T6 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the first terminal T1 to the fourth terminal T4 and the sixth terminal T6 are equivalently connected by capacitance and function as a circuit.
  • FIG. 13 is an equivalent circuit diagram schematically showing a sixth connection state of the antenna matching circuit according to the second embodiment.
  • the sixth terminal T6 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A.
  • the first terminal T1 to the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state.
  • the first terminal T1 to the fifth terminal T5 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs.
  • the first terminal T1 to the fifth terminal T5 are equally capacitively connected and function as a circuit.
  • connection state of the first inductor 21, the second inductor 22, the third inductor 23 and the first reference potential 50 is switched by the operation of the switch 30A.
  • the antenna matching circuit 1A has more connection states than the above-described first embodiment, and can appropriately switch the frequency according to the antenna characteristics.
  • FIG. 14 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the second embodiment.
  • the resonance frequency is different in each of the first connection state M1 to the sixth connection state M6.
  • the resonance frequency of the antenna matching circuit 1A is around 2.8 GHz.
  • the resonance frequency of the antenna matching circuit 1A is around 6.5 GHz.
  • the resonance frequency of the antenna matching circuit 1A is around 4.4 GHz.
  • the resonance frequency of the antenna matching circuit 1A is around 3.9 GHz.
  • the resonance frequency of the antenna matching circuit 1A is around 7.2 GHz.
  • the resonance frequency of the antenna matching circuit 1A is around 4.5 GHz.
  • the resonance frequency of the antenna matching circuit 1A can be changed by switching the connection state of the first inductor 21, the second inductor 22, the third inductor 23, and the first reference potential 50.
  • the antenna matching circuit 1A can realize a plurality of different antenna characteristics with one common mode choke coil 20A.
  • the second embodiment is not limited to the case of switching the connection state between the six terminals of the common mode choke coil 20A and the first reference potential 50. That is, the switch 30A can perform impedance matching as long as the connection state of at least two of the six terminals can be switched.
  • FIG. 15 is a circuit diagram schematically showing an antenna matching circuit according to a third embodiment.
  • the third embodiment unlike the first embodiment and the second embodiment described above, a configuration in which the fourth inductor 24 is provided and the fourth inductor 24 is connected in series with the first inductor 21 will be described.
  • the first inductor 21 and the fourth inductor 24 are connected in series between the first terminal T1 and the second terminal T2. ..
  • One end side of the first inductor 21 is electrically connected to the first terminal T1
  • the other end side of the first inductor 21 is electrically connected to one end side of the fourth inductor 24.
  • the other end side of the fourth inductor 24 is electrically connected to the second terminal T2.
  • the common mode choke coil 20B has four terminals as in the first embodiment described above, but the inductance values between the first terminal T1 and the second terminal T2 are different.
  • the switch 30B switches the connection state between one terminal of the first terminal T1 to the fourth terminal T4 and the first reference potential 50 in the same manner as in the first embodiment described above.
  • FIG. 16 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 17 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 18 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the third embodiment.
  • FIG. 19 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the third embodiment.
  • each of the first connection state M1 to the fourth connection state M4 has four terminals, a first reference potential 50, a second reference potential 51, and a parasitic capacitance Cs.
  • the connection configuration with and from is the same as that of the first embodiment shown in FIGS. 2 to 5. That is, the antenna matching circuit 1B can be switched to four types of connection states by one common mode choke coil 20B.
  • the first inductor 21 and the fourth inductor 24 are connected in series between the first terminal T1 and the second terminal T2, the first inductor 21, the second inductor 22, and the fourth inductor 24
  • the binding state is different from that of the first embodiment.
  • the third embodiment it is possible to realize a frequency characteristic different from that of the first embodiment.
  • the number of terminals in the above-mentioned common mode choke coils 20, 20A and 20B is not limited to 4 or 6.
  • the number of terminals may be 7 or more.
  • Antenna matching circuit 10 Antenna 20, 20A, 20B Common mode choke coil 21 1st inductor 22 2nd inductor 23 3rd inductor 24 4th inductor 30, 30A, 30B Switch 40
  • Control circuit 50 1st reference potential 51 2nd reference potential Cs parasitic capacitance M1 1st connection state M2 2nd connection state M3 3rd connection state M4 4th connection state M5 5th connection state M6 6th connection state T1 1st terminal T2 2nd terminal T3 3rd terminal T4 4th terminal T5 5th terminal T6 6th terminal TS1, TS2, TS3, TS4 Switch side terminal

Abstract

An antenna matching circuit according to the present invention comprises: an antenna; a first inductor that is connected to the antenna; a second inductor that forms a mutual inductance together with the first inductor; a plurality of terminals that are electrically connected to respective ones of the ends of the first inductor and second inductor; and a switch that switches connected states between a first reference potential and at least two of the plurality of terminals, wherein those ones of the plurality of terminals which are in unconnected state to the first reference potential are in open state.

Description

アンテナ整合回路Antenna matching circuit
　本発明は、アンテナ整合回路に関する。 The present invention relates to an antenna matching circuit.
　アンテナ整合回路は、アンテナと、給電回路とのインピーダンス整合を図るために設けられる。アンテナ整合回路は、例えば複数のインダクタと、複数のコンデンサとを組み合わせて構成される。複数のインダクタと、複数のコンデンサの組み合わせについては、必要な周波数やアンテナ特性に応じて調整される。 The antenna matching circuit is provided to match the impedance between the antenna and the feeding circuit. The antenna matching circuit is composed of, for example, a combination of a plurality of inductors and a plurality of capacitors. The combination of multiple inductors and multiple capacitors is adjusted according to the required frequency and antenna characteristics.
　下記特許文献１には、インダクタンス値を変化させることができる可変インダクタについて記載されている。特許文献２には、可変インダクタを用いたアンテナ装置について記載されている。特許文献１、２ともに、インダクタの結合を利用して可変インダクタを構成している。 The following Patent Document 1 describes a variable inductor capable of changing the inductance value. Patent Document 2 describes an antenna device using a variable inductor. In both Patent Documents 1 and 2, a variable inductor is configured by utilizing the coupling of inductors.
特開２０１１－１５９９５３号公報Japanese Unexamined Patent Publication No. 2011-159953 特開２００７－１２８９８５号公報JP-A-2007-128985
　特許文献１、２では、複数のインダクタの各端子がグランド、コンデンサ、抵抗素子等のいずれかに接続される。このため、特許文献１、２の可変インダクタを採用したアンテナ整合回路では、１つのアンテナで複数の周波数での整合を図る場合、複数のインダクタに接続される部品の点数が増加する。したがって、部品を搭載するための広い面積が必要であり、また、これらを接続する配線の数も増加する可能性がある。 In Patent Documents 1 and 2, each terminal of a plurality of inductors is connected to any one of a ground, a capacitor, a resistance element, and the like. Therefore, in the antenna matching circuit using the variable inductors of Patent Documents 1 and 2, when matching at a plurality of frequencies with one antenna, the number of parts connected to the plurality of inductors increases. Therefore, a large area for mounting the components is required, and the number of wirings connecting them may increase.
　本発明は、複数の周波数での整合を図るとともに、小型化が可能なアンテナ整合回路を提供することを目的とする。 An object of the present invention is to provide an antenna matching circuit capable of matching at a plurality of frequencies and being miniaturized.
　本発明の一側面のアンテナ整合回路は、アンテナと、前記アンテナに接続される第１インダクタと、前記第１インダクタとの間に相互インダクタンスを形成する第２インダクタと、前記第１インダクタ及び前記第２インダクタのそれぞれの両端に電気的に接続される複数の端子と、複数の前記端子のうち、少なくとも２つの前記端子と、第１基準電位との接続状態を切り替えるスイッチと、を有し、複数の前記端子のうち、前記第１基準電位と非接続状態の前記端子は、開放状態である。 The antenna matching circuit on one aspect of the present invention includes an antenna, a first inductor connected to the antenna, a second inductor that forms a mutual inductance between the first inductor, the first inductor, and the first inductor. It has a plurality of terminals electrically connected to both ends of each of the two inductors, at least two of the terminals, and a switch for switching the connection state with the first reference potential. Of the terminals, the terminal that is not connected to the first reference potential is in an open state.
　本発明のアンテナ整合回路によれば、複数の周波数での整合を図るとともに、小型化が可能である。 According to the antenna matching circuit of the present invention, matching at a plurality of frequencies can be achieved and miniaturization is possible.
図１は、第１実施形態に係るアンテナ整合回路を模式的に示す回路図である。FIG. 1 is a circuit diagram schematically showing an antenna matching circuit according to the first embodiment. 図２は、第１実施形態に係るアンテナ整合回路の第１接続状態を模式的に示す等価回路図である。FIG. 2 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the first embodiment. 図３は、第１実施形態に係るアンテナ整合回路の第２接続状態を模式的に示す等価回路図である。FIG. 3 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the first embodiment. 図４は、第１実施形態に係るアンテナ整合回路の第３接続状態を模式的に示す等価回路図である。FIG. 4 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the first embodiment. 図５は、第１実施形態に係るアンテナ整合回路の第４接続状態を模式的に示す等価回路図である。FIG. 5 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the first embodiment. 図６は、第１実施形態に係るアンテナ整合回路の、異なる接続状態ごとの、反射係数と周波数との関係を示すグラフである。FIG. 6 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the first embodiment. 図７は、第２実施形態に係るアンテナ整合回路を模式的に示す回路図である。FIG. 7 is a circuit diagram schematically showing an antenna matching circuit according to the second embodiment. 図８は、第２実施形態に係るアンテナ整合回路の第１接続状態を模式的に示す等価回路図である。FIG. 8 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the second embodiment. 図９は、第２実施形態に係るアンテナ整合回路の第２接続状態を模式的に示す等価回路図である。FIG. 9 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the second embodiment. 図１０は、第２実施形態に係るアンテナ整合回路の第３接続状態を模式的に示す等価回路図である。FIG. 10 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the second embodiment. 図１１は、第２実施形態に係るアンテナ整合回路の第４接続状態を模式的に示す等価回路図である。FIG. 11 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the second embodiment. 図１２は、第２実施形態に係るアンテナ整合回路の第５接続状態を模式的に示す等価回路図である。FIG. 12 is an equivalent circuit diagram schematically showing a fifth connection state of the antenna matching circuit according to the second embodiment. 図１３は、第２実施形態に係るアンテナ整合回路の第６接続状態を模式的に示す等価回路図である。FIG. 13 is an equivalent circuit diagram schematically showing a sixth connection state of the antenna matching circuit according to the second embodiment. 図１４は、第２実施形態に係るアンテナ整合回路の、異なる接続状態ごとの、反射係数と周波数との関係を示すグラフである。FIG. 14 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the second embodiment. 図１５は、第３実施形態に係るアンテナ整合回路を模式的に示す回路図である。FIG. 15 is a circuit diagram schematically showing an antenna matching circuit according to a third embodiment. 図１６は、第３実施形態に係るアンテナ整合回路の第１接続状態を模式的に示す等価回路図である。FIG. 16 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the third embodiment. 図１７は、第３実施形態に係るアンテナ整合回路の第２接続状態を模式的に示す等価回路図である。FIG. 17 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the third embodiment. 図１８は、第３実施形態に係るアンテナ整合回路の第３接続状態を模式的に示す等価回路図である。FIG. 18 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the third embodiment. 図１９は、第３実施形態に係るアンテナ整合回路の第４接続状態を模式的に示す等価回路図である。FIG. 19 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the third embodiment.
　以下に、本発明のアンテナ整合回路の実施の形態を図面に基づいて詳細に説明する。なお、この実施の形態により本発明が限定されるものではない。各実施の形態は例示であり、異なる実施の形態で示した構成の部分的な置換又は組み合わせが可能であることは言うまでもない。第２実施形態以降では第１実施形態と共通の事柄についての記述を省略し、異なる点についてのみ説明する。特に、同様の構成による同様の作用効果については実施形態毎には逐次言及しない。 Hereinafter, embodiments of the antenna matching circuit of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment. It goes without saying that each embodiment is an example, and partial replacement or combination of the configurations shown in different embodiments is possible. In the second and subsequent embodiments, the description of matters common to those of the first embodiment will be omitted, and only the differences will be described. In particular, the same action and effect due to the same configuration will not be mentioned sequentially for each embodiment.
（第１実施形態）
　図１は、第１実施形態に係るアンテナ整合回路を模式的に示す回路図である。図１に示すように、アンテナ整合回路１は、アンテナ１０と、コモンモードチョークコイル２０と、スイッチ３０と、制御回路４０と、を有する。アンテナ整合回路１は、アンテナ１０のインピーダンス整合を行うための回路である。 (First Embodiment)
FIG. 1 is a circuit diagram schematically showing an antenna matching circuit according to the first embodiment. As shown in FIG. 1, the antenna matching circuit 1 includes an antenna 10, a common mode choke coil 20, a switch 30, and a control circuit 40. The antenna matching circuit 1 is a circuit for performing impedance matching of the antenna 10.
　アンテナ１０は、例えば、携帯電話、スマートフォンあるいはタブレット端末などの携帯端末や、通信機能を備えたパーソナルコンピュータなどに搭載される。アンテナ１０は、一例として、０．６ＧＨｚ以上６ＧＨｚ以下の周波数帯域の信号を送受信する。 The antenna 10 is mounted on, for example, a mobile terminal such as a mobile phone, a smartphone or a tablet terminal, a personal computer having a communication function, or the like. As an example, the antenna 10 transmits and receives a signal in a frequency band of 0.6 GHz or more and 6 GHz or less.
　コモンモードチョークコイル２０は、互いに磁気的に結合された第１インダクタ２１と、第２インダクタ２２を有する。すなわち、第１インダクタ２１と第２インダクタ２２との間に相互インダクタンスが形成される。 The common mode choke coil 20 has a first inductor 21 and a second inductor 22 that are magnetically coupled to each other. That is, a mutual inductance is formed between the first inductor 21 and the second inductor 22.
　第１インダクタ２１は、アンテナ１０に接続される。具体的には、第１インダクタ２１は、一端側が第１端子Ｔ１に電気的に接続され、他端側が第２端子Ｔ２に電気的に接続される。第１インダクタ２１は、第１端子Ｔ１を介してアンテナ１０と電気的に接続される。また、第２インダクタ２２は、一端側が第３端子Ｔ３に電気的に接続され、他端側が第４端子Ｔ４に電気的に接続される。本実施形態のコモンモードチョークコイル２０は、４つの端子を有する。ただし、これに限定されず、コモンモードチョークコイル２０は、５つ以上の端子を有していてもよい。 The first inductor 21 is connected to the antenna 10. Specifically, one end of the first inductor 21 is electrically connected to the first terminal T1, and the other end is electrically connected to the second terminal T2. The first inductor 21 is electrically connected to the antenna 10 via the first terminal T1. Further, one end side of the second inductor 22 is electrically connected to the third terminal T3, and the other end side is electrically connected to the fourth terminal T4. The common mode choke coil 20 of this embodiment has four terminals. However, the present invention is not limited to this, and the common mode choke coil 20 may have five or more terminals.
　コモンモードチョークコイル２０は、どのような構成であってもよいが、例えば第１インダクタ２１及び第２インダクタ２２は、一体型のコモンモードチョークコイル２０であることが望ましい。一体型とは、例えば、第１インダクタ２１を形成するコイルと、第２インダクタ２２を形成するコイルが、磁性体からなる共通のコア（例えばフェライトコア）に巻き回された構成を有する。なお、一体型に限定されず、コモンモードチョークコイル２０は、各インダクタが磁気結合される構成であればよい。コモンモードチョークコイル２０は、各インダクタが個別の分割されたコアに形成されてもよいし、平面コイルで構成されていてもよい。 The common mode choke coil 20 may have any configuration, but for example, it is desirable that the first inductor 21 and the second inductor 22 are integrated common mode choke coils 20. The integrated type has, for example, a configuration in which a coil forming the first inductor 21 and a coil forming the second inductor 22 are wound around a common core (for example, a ferrite core) made of a magnetic material. The common mode choke coil 20 is not limited to the integrated type, and may have a configuration in which each inductor is magnetically coupled. In the common mode choke coil 20, each inductor may be formed in an individual divided core, or may be composed of a flat coil.
　スイッチ３０は、コモンモードチョークコイル２０の複数の端子（第１端子Ｔ１から第４端子Ｔ４）のうち少なくとも２つの端子と、第１基準電位５０との接続状態を切り替える素子である。具体的には、スイッチ３０は、第１端子Ｔ１から第４端子Ｔ４にそれぞれ対応して設けられたスイッチ側端子ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４を有する。スイッチ３０は、制御回路４０から供給される制御信号Ｓｉに基づいて、スイッチ側端子ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４のうち１つのスイッチ側端子と、第１基準電位５０とを接続する。これにより、スイッチ３０の動作により、第１端子Ｔ１から第４端子Ｔ４のうち、１つの端子が第１基準電位５０と電気的に接続される。 The switch 30 is an element that switches the connection state between at least two terminals of the plurality of terminals (first terminal T1 to fourth terminal T4) of the common mode choke coil 20 and the first reference potential 50. Specifically, the switch 30 has switch-side terminals TS1, TS2, TS3, and TS4 provided corresponding to the first terminal T1 to the fourth terminal T4, respectively. The switch 30 connects one of the switch-side terminals TS1, TS2, TS3, and TS4 to the first reference potential 50 based on the control signal Si supplied from the control circuit 40. As a result, one of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30.
　スイッチ側端子ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４のうち、第１基準電位５０と非接続状態の端子は開放状態である。つまり、第１基準電位５０と非接続状態のスイッチ側端子は、他の配線や素子等、どこにも接続されていない状態である。これにより、スイッチ３０の動作により、第１端子Ｔ１から第４端子Ｔ４のうち、第１基準電位５０と非接続状態の端子は、開放状態となる。 Of the switch side terminals TS1, TS2, TS3, and TS4, the terminal that is not connected to the first reference potential 50 is in the open state. That is, the switch-side terminal that is not connected to the first reference potential 50 is not connected to any other wiring, element, or the like. As a result, due to the operation of the switch 30, the terminal of the first terminal T1 to the fourth terminal T4 that is not connected to the first reference potential 50 is opened.
　スイッチ３０は、例えば半導体スイッチである。半導体スイッチは、例えばＦＥＴ（Field　Effect　Transistor）である。制御回路４０は、例えば、ＩＣ（Integrated　Circuit）として構成される。制御回路４０は、アンテナ１０の送受信を制御するＲＦＩＣ（Radio　Frequency　Integrated　Circuit）に含まれていてもよい。また、第１基準電位５０は、固定された電位であればよく、例えばグランド電位である。具体的には、第１基準電位５０は、アンテナ整合回路１が実装される基板のグランドや筐体のグランドである。 The switch 30 is, for example, a semiconductor switch. The semiconductor switch is, for example, a FET (Field Effect Transistor). The control circuit 40 is configured as, for example, an IC (Integrated Circuit). The control circuit 40 may be included in an RFIC (Radio Frequency Integrated Circuit) that controls transmission / reception of the antenna 10. Further, the first reference potential 50 may be a fixed potential, for example, a ground potential. Specifically, the first reference potential 50 is the ground of the substrate on which the antenna matching circuit 1 is mounted or the ground of the housing.
　次に、図２から図５を参照して、スイッチ３０の動作によるアンテナ整合回路１の各接続状態の切り替えについて説明する。なお、図２から図５では、スイッチ３０を省略して、各端子の接続状態を等価的に示している。 Next, with reference to FIGS. 2 to 5, switching of each connection state of the antenna matching circuit 1 by the operation of the switch 30 will be described. In addition, in FIGS. 2 to 5, the switch 30 is omitted, and the connection state of each terminal is shown equivalently.
　図２は、第１実施形態に係るアンテナ整合回路の第１接続状態を模式的に示す等価回路図である。図２に示すように、第１接続状態Ｍ１では、スイッチ３０の動作により、第１端子Ｔ１から第４端子Ｔ４のうち、第１端子Ｔ１が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第４端子Ｔ４のうち、第１基準電位５０と非接続状態の第２端子Ｔ２、第３端子Ｔ３及び第４端子Ｔ４は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第２端子Ｔ２、第３端子Ｔ３及び第４端子Ｔ４は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第２端子Ｔ２、第３端子Ｔ３及び第４端子Ｔ４は、等価的に容量接続されて、回路として機能する。 FIG. 2 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the first embodiment. As shown in FIG. 2, in the first connection state M1, the first terminal T1 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30. Further, of the first terminal T1 to the fourth terminal T4, the second terminal T2, the third terminal T3, and the fourth terminal T4, which are not connected to the first reference potential 50, are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the second terminal T2, the third terminal T3, and the fourth terminal T4 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the second terminal T2, the third terminal T3, and the fourth terminal T4 are equivalently capacitively connected and function as a circuit.
　寄生容量Ｃｓは、第１インダクタ２１及び第２インダクタ２２を形成するコイルと、他の導体との間に形成される容量成分である。他の導体は、例えば、コモンモードチョークコイル２０が実装される基板に設けられた電極、配線、あるいは、アンテナ整合回路１が組み込まれる通信装置の部品や筐体等である。また、第２基準電位５１は、第１基準電位５０と同じ電位を有するグランドでもよく、第１基準電位５０とは異なる電位であってもよい。 The parasitic capacitance Cs is a capacitance component formed between the coil forming the first inductor 21 and the second inductor 22 and another conductor. Other conductors are, for example, electrodes and wiring provided on a substrate on which the common mode choke coil 20 is mounted, or parts and housings of a communication device in which the antenna matching circuit 1 is incorporated. Further, the second reference potential 51 may be a ground having the same potential as the first reference potential 50, or may be a potential different from the first reference potential 50.
　図３は、第１実施形態に係るアンテナ整合回路の第２接続状態を模式的に示す等価回路図である。図３に示すように、第２接続状態Ｍ２では、スイッチ３０の動作により、第１端子Ｔ１から第４端子Ｔ４のうち、第２端子Ｔ２が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第４端子Ｔ４のうち、第１基準電位５０と非接続状態の第１端子Ｔ１、第３端子Ｔ３及び第４端子Ｔ４は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１、第３端子Ｔ３及び第４端子Ｔ４は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１、第３端子Ｔ３及び第４端子Ｔ４は、等価的に容量接続されて、回路として機能する。 FIG. 3 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the first embodiment. As shown in FIG. 3, in the second connection state M2, the second terminal T2 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30. Further, of the first terminal T1 to the fourth terminal T4, the first terminal T1, the third terminal T3, and the fourth terminal T4, which are not connected to the first reference potential 50, are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the first terminal T1, the third terminal T3, and the fourth terminal T4 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the first terminal T1, the third terminal T3, and the fourth terminal T4 are equivalently capacitively connected and function as a circuit.
　図４は、第１実施形態に係るアンテナ整合回路の第３接続状態を模式的に示す等価回路図である。図４に示すように、第３接続状態Ｍ３では、スイッチ３０の動作により、第１端子Ｔ１から第４端子Ｔ４のうち、第３端子Ｔ３が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第４端子Ｔ４のうち、第１基準電位５０と非接続状態の第１端子Ｔ１、第２端子Ｔ２及び第４端子Ｔ４は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１、第２端子Ｔ２及び第４端子Ｔ４は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１、第２端子Ｔ２及び第４端子Ｔ４は、等価的に容量接続されて、回路として機能する。 FIG. 4 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the first embodiment. As shown in FIG. 4, in the third connection state M3, the third terminal T3 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30. Further, of the first terminal T1 to the fourth terminal T4, the first terminal T1, the second terminal T2, and the fourth terminal T4, which are not connected to the first reference potential 50, are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the first terminal T1, the second terminal T2 and the fourth terminal T4 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the first terminal T1, the second terminal T2, and the fourth terminal T4 are equivalently capacitively connected and function as a circuit.
　図５は、第１実施形態に係るアンテナ整合回路の第４接続状態を模式的に示す等価回路図である。図５に示すように、第４接続状態Ｍ４では、スイッチ３０の動作により、第１端子Ｔ１から第４端子Ｔ４のうち、第４端子Ｔ４が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第４端子Ｔ４のうち、第１基準電位５０と非接続状態の第１端子Ｔ１、第２端子Ｔ２及び第３端子Ｔ３は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１、第２端子Ｔ２及び第３端子Ｔ３は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１、第２端子Ｔ２及び第３端子Ｔ３は、等価的に容量接続されて、回路として機能する。 FIG. 5 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the first embodiment. As shown in FIG. 5, in the fourth connection state M4, the fourth terminal T4 of the first terminal T1 to the fourth terminal T4 is electrically connected to the first reference potential 50 by the operation of the switch 30. Further, of the first terminal T1 to the fourth terminal T4, the first terminal T1, the second terminal T2, and the third terminal T3, which are not connected to the first reference potential 50, are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the first terminal T1, the second terminal T2 and the third terminal T3 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the first terminal T1, the second terminal T2, and the third terminal T3 are equivalently capacitively connected and function as a circuit.
　図２から図５に示すように、アンテナ整合回路１は、アンテナ１０の周波数や特性に応じて、スイッチ３０の動作により、第１インダクタ２１及び第２インダクタ２２の複数の端子と、第１基準電位５０との接続状態を切り替えることができる。アンテナ整合回路１は、１つのコモンモードチョークコイル２０で４種類の接続状態に切り替えることができる。この結果、コモンモードチョークコイル２０の第１インダクタ２１と第２インダクタ２２との結合状態（磁界の方向）が変わる。アンテナ整合回路１は、コモンモード、ディファレンシャルモードの相互インダクタンスを利用してインピーダンスを変更することができる。 As shown in FIGS. 2 to 5, the antenna matching circuit 1 has a plurality of terminals of the first inductor 21 and the second inductor 22 and a first reference by the operation of the switch 30 according to the frequency and characteristics of the antenna 10. The connection state with the potential 50 can be switched. The antenna matching circuit 1 can be switched to four types of connection states by one common mode choke coil 20. As a result, the coupling state (direction of the magnetic field) between the first inductor 21 and the second inductor 22 of the common mode choke coil 20 changes. The antenna matching circuit 1 can change the impedance by utilizing the mutual inductance of the common mode and the differential mode.
　また、非接続状態の端子は、開放状態であり、インピーダンスを変更するための素子（コンデンサやインダクタ等）と接続する必要がない。さらに、非接続状態の端子は、等価的に寄生容量Ｃｓを介して第２基準電位５１に接続される。つまり、非接続状態の端子と第２基準電位５１とを接続する配線等を設ける必要がない。したがって、アンテナ整合回路１は、小型化を実現することができる。 In addition, the terminals in the unconnected state are in the open state, and there is no need to connect them to elements (capacitors, inductors, etc.) for changing impedance. Further, the terminals in the unconnected state are equivalently connected to the second reference potential 51 via the parasitic capacitance Cs. That is, it is not necessary to provide wiring or the like for connecting the terminal in the non-connected state and the second reference potential 51. Therefore, the antenna matching circuit 1 can be miniaturized.
　図６は、第１実施形態に係るアンテナ整合回路の、異なる接続状態ごとの、反射係数と周波数との関係を示すグラフである。図６に示すグラフ１は、縦軸にＳパラメータのＳ１１（反射係数）を示し、横軸に周波数を示す。 FIG. 6 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the first embodiment. In the graph 1 shown in FIG. 6, the vertical axis shows S11 (reflection coefficient) of the S parameter, and the horizontal axis shows the frequency.
　図６に示すように、第１接続状態Ｍ１から第４接続状態Ｍ４のそれぞれで共振周波数が異なる。具体的には、第１接続状態Ｍ１では、アンテナ整合回路１の共振周波数は、９ＧＨｚ、１１ＧＨｚ付近である。第２接続状態Ｍ２では、アンテナ整合回路１の共振周波数は、１０ＧＨｚ付近である。第３接続状態Ｍ３では、アンテナ整合回路１の共振周波数は、９ＧＨｚ付近である。第４接続状態Ｍ４では、アンテナ整合回路１の共振周波数は、３ＧＨｚ付近である。 As shown in FIG. 6, the resonance frequency is different in each of the first connection state M1 to the fourth connection state M4. Specifically, in the first connection state M1, the resonance frequencies of the antenna matching circuit 1 are around 9 GHz and 11 GHz. In the second connection state M2, the resonance frequency of the antenna matching circuit 1 is around 10 GHz. In the third connection state M3, the resonance frequency of the antenna matching circuit 1 is around 9 GHz. In the fourth connection state M4, the resonance frequency of the antenna matching circuit 1 is around 3 GHz.
　このように、第１インダクタ２１、第２インダクタ２２及び第１基準電位５０の接続状態を切り替えることで、アンテナ整合回路１の共振周波数を変更できることが示された。これにより、アンテナ整合回路１は、１つのコモンモードチョークコイル２０で、複数の異なるアンテナ特性を実現できる。 As described above, it was shown that the resonance frequency of the antenna matching circuit 1 can be changed by switching the connection state of the first inductor 21, the second inductor 22, and the first reference potential 50. As a result, the antenna matching circuit 1 can realize a plurality of different antenna characteristics with one common mode choke coil 20.
　なお、図１から図５の回路図は、説明を分かりやすくするために模式的に示している。アンテナ整合回路１は、アンテナ１０に要求される特性に応じて、コンデンサ素子、インダクタ素子、抵抗素子等が設けられていてもよく、あるいは、アンテナ１０の送受信に用いられるフィルタやアンプなどが接続されていてもよい。 Note that the circuit diagrams of FIGS. 1 to 5 are schematically shown for the sake of clarity of explanation. The antenna matching circuit 1 may be provided with a capacitor element, an inductor element, a resistance element, etc., depending on the characteristics required for the antenna 10, or a filter, an amplifier, or the like used for transmission / reception of the antenna 10 is connected. You may be.
　なお、第１実施形態では、スイッチ３０の動作により、コモンモードチョークコイル２０の４つの端子と、第１基準電位５０との接続状態を切り替える例を説明したが、これに限定されない。すなわち、スイッチ３０は、４つの端子のうち、少なくとも２つの端子の接続状態を切り替え可能であれば、インピーダンス整合を行うことができる。この場合、４つの端子のうち、１つ又は２つの端子は、いずれの接続状態でも、第１基準電位５０に接続されず開放状態とすることができる。言い換えると、アンテナ整合回路１は、第１接続状態Ｍ１から第４接続状態Ｍ４のうち、少なくとも２つの接続状態を切り替えることができればよい。 In the first embodiment, an example of switching the connection state between the four terminals of the common mode choke coil 20 and the first reference potential 50 by the operation of the switch 30 has been described, but the present invention is not limited to this. That is, the switch 30 can perform impedance matching as long as the connection state of at least two of the four terminals can be switched. In this case, one or two of the four terminals can be left open without being connected to the first reference potential 50 in any of the connected states. In other words, the antenna matching circuit 1 only needs to be able to switch at least two connection states from the first connection state M1 to the fourth connection state M4.
　以上説明したように、本実施形態のアンテナ整合回路１は、アンテナ１０と、アンテナ１０に接続される第１インダクタ２１と、第１インダクタ２１との間に相互インダクタンスを形成する第２インダクタ２２と、第１インダクタ２１及び第２インダクタ２２のそれぞれの両端に電気的に接続される複数の端子（第１端子Ｔ１から第４端子Ｔ４）と、複数の端子のうち少なくとも２つの端子と、第１基準電位５０との接続状態を切り替えるスイッチ３０と、を有する。複数の端子のうち、第１基準電位５０と非接続状態の端子は、開放状態である。 As described above, the antenna matching circuit 1 of the present embodiment includes the antenna 10, the first inductor 21 connected to the antenna 10, and the second inductor 22 that forms a mutual inductance between the first inductor 21. , A plurality of terminals (first terminal T1 to fourth terminal T4) electrically connected to both ends of the first inductor 21 and the second inductor 22, at least two of the plurality of terminals, and a first terminal. It has a switch 30 for switching the connection state with the reference potential 50. Of the plurality of terminals, the terminal that is not connected to the first reference potential 50 is in the open state.
（第２実施形態）
　図７は、第２実施形態に係るアンテナ整合回路を模式的に示す回路図である。第２実施形態では、上述した第１実施形態とは異なり、コモンモードチョークコイル２０Ａが、さらに第３インダクタ２３を有する構成について説明する。 (Second Embodiment)
FIG. 7 is a circuit diagram schematically showing an antenna matching circuit according to the second embodiment. In the second embodiment, unlike the first embodiment described above, the configuration in which the common mode choke coil 20A further includes the third inductor 23 will be described.
　具体的には、図７に示すように、アンテナ整合回路１Ａのコモンモードチョークコイル２０Ａは、さらに第３インダクタ２３と、第３インダクタ２３の両端に電気的に接続された２つの端子（第５端子Ｔ５及び第６端子Ｔ６）と、を有する。第３インダクタ２３は、第１インダクタ２１及び第２インダクタ２２の少なくとも一方との間に相互インダクタンスを形成する。本実施形態の第３インダクタ２３は、第１インダクタ２１及び第２インダクタ２２と、一体型のコモンモードチョークコイル２０Ａとして形成される。つまり、コモンモードチョークコイル２０Ａは、第１インダクタ２１、第２インダクタ２２及び第３インダクタ２３をそれぞれ形成するコイルが、共通のコアに巻き回されて構成される。 Specifically, as shown in FIG. 7, the common mode choke coil 20A of the antenna matching circuit 1A further has a third inductor 23 and two terminals (fifth) electrically connected to both ends of the third inductor 23. It has a terminal T5 and a sixth terminal T6). The third inductor 23 forms a mutual inductance with at least one of the first inductor 21 and the second inductor 22. The third inductor 23 of the present embodiment is formed as a common mode choke coil 20A integrated with the first inductor 21 and the second inductor 22. That is, the common mode choke coil 20A is configured by winding the coils forming the first inductor 21, the second inductor 22, and the third inductor 23 around a common core.
　スイッチ３０Ａは、第１端子Ｔ１から第６端子Ｔ６にそれぞれ対応して設けられたスイッチ側端子ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４、ＴＳ５、ＴＳ６を有する。スイッチ３０Ａは、制御回路４０から供給される制御信号Ｓｉに基づいて、スイッチ側端子ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４、ＴＳ５、ＴＳ６のうち１つのスイッチ側端子と、第１基準電位５０とを接続する。これにより、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、１つの端子が第１基準電位５０と電気的に接続される。本実施形態のスイッチ３０Ａは、第３インダクタ２３の２つの端子（第５端子Ｔ５及び第６端子Ｔ６）を含む、６つの端子と、第１基準電位５０との接続状態を切り替える。 The switch 30A has switch-side terminals TS1, TS2, TS3, TS4, TS5, and TS6 provided corresponding to the first terminal T1 to the sixth terminal T6, respectively. The switch 30A connects one of the switch-side terminals TS1, TS2, TS3, TS4, TS5, and TS6 with the first reference potential 50 based on the control signal Si supplied from the control circuit 40. .. As a result, one of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. The switch 30A of the present embodiment switches the connection state between the six terminals including the two terminals (fifth terminal T5 and sixth terminal T6) of the third inductor 23 and the first reference potential 50.
　また、スイッチ側端子ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４、ＴＳ５、ＴＳ６のうち、第１基準電位５０と非接続状態の端子は開放状態である。すなわち、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の端子は、開放状態となる。 Further, of the switch side terminals TS1, TS2, TS3, TS4, TS5, and TS6, the terminal that is not connected to the first reference potential 50 is in the open state. That is, by the operation of the switch 30A, the terminal of the first terminal T1 to the sixth terminal T6 that is not connected to the first reference potential 50 is opened.
　次に、図８から図１３を参照して、スイッチ３０Ａの動作によるアンテナ整合回路１Ａの各接続状態の切り替えについて説明する。なお、図８から図１３では、スイッチ３０Ａを省略して示している。 Next, with reference to FIGS. 8 to 13, switching of each connection state of the antenna matching circuit 1A by the operation of the switch 30A will be described. Note that, in FIGS. 8 to 13, the switch 30A is omitted.
　図８は、第２実施形態に係るアンテナ整合回路の第１接続状態を模式的に示す等価回路図である。図８に示すように、第１接続状態Ｍ１では、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第１端子Ｔ１が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の第２端子Ｔ２から第６端子Ｔ６は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第２端子Ｔ２から第６端子Ｔ６は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第２端子Ｔ２から第６端子Ｔ６は、等価的に容量接続されて、回路として機能する。 FIG. 8 is an equivalent circuit diagram schematically showing the first connection state of the antenna matching circuit according to the second embodiment. As shown in FIG. 8, in the first connection state M1, the first terminal T1 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. Further, of the first terminal T1 to the sixth terminal T6, the second terminal T2 to the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state. Equivalently, in the high frequency band used for transmission and reception of the antenna 10, the second terminal T2 to the sixth terminal T6 are connected to the second reference potential 51 via the parasitic capacitance Cs, respectively. As a result, the second terminal T2 to the sixth terminal T6 are equivalently connected by capacitance and function as a circuit.
　図９は、第２実施形態に係るアンテナ整合回路の第２接続状態を模式的に示す等価回路図である。図９に示すように、第２接続状態Ｍ２では、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第２端子Ｔ２が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の第１端子Ｔ１及び第３端子Ｔ３から第６端子Ｔ６は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１及び第３端子Ｔ３から第６端子Ｔ６は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１及び第３端子Ｔ３から第６端子Ｔ６は、等価的に容量接続されて、回路として機能する。 FIG. 9 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the second embodiment. As shown in FIG. 9, in the second connection state M2, the second terminal T2 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. Further, of the first terminal T1 to the sixth terminal T6, the first terminal T1 and the third terminal T3 to the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the first terminal T1 and the third terminal T3 to the sixth terminal T6 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the first terminal T1 and the third terminal T3 to the sixth terminal T6 are equivalently connected by capacitance and function as a circuit.
　図１０は、第２実施形態に係るアンテナ整合回路の第３接続状態を模式的に示す等価回路図である。図１０に示すように、第３接続状態Ｍ３では、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第３端子Ｔ３が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の第１端子Ｔ１、第２端子Ｔ２、第４端子Ｔ４、第５端子Ｔ５及び第６端子Ｔ６は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１、第２端子Ｔ２、第４端子Ｔ４、第５端子Ｔ５及び第６端子Ｔ６は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１、第２端子Ｔ２、第４端子Ｔ４、第５端子Ｔ５及び第６端子Ｔ６は、等価的に容量接続されて、回路として機能する。 FIG. 10 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the second embodiment. As shown in FIG. 10, in the third connection state M3, the third terminal T3 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. Further, among the first terminal T1 to the sixth terminal T6, the first terminal T1, the second terminal T2, the fourth terminal T4, the fifth terminal T5, and the sixth terminal T6, which are not connected to the first reference potential 50, are It is in an open state. In the high frequency band used for transmission and reception of the antenna 10, equivalently, the first terminal T1, the second terminal T2, the fourth terminal T4, the fifth terminal T5, and the sixth terminal T6 are respectively via the parasitic capacitance Cs. It is connected to the second reference potential 51. As a result, the first terminal T1, the second terminal T2, the fourth terminal T4, the fifth terminal T5, and the sixth terminal T6 are equally capacitively connected and function as a circuit.
　図１１は、第２実施形態に係るアンテナ整合回路の第４接続状態を模式的に示す等価回路図である。図１１に示すように、第４接続状態Ｍ４では、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第４端子Ｔ４が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の第１端子Ｔ１、第２端子Ｔ２、第３端子Ｔ３、第５端子Ｔ５及び第６端子Ｔ６は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１、第２端子Ｔ２、第３端子Ｔ３、第５端子Ｔ５及び第６端子Ｔ６は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１、第２端子Ｔ２、第３端子Ｔ３、第５端子Ｔ５及び第６端子Ｔ６は、等価的に容量接続されて、回路として機能する。 FIG. 11 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the second embodiment. As shown in FIG. 11, in the fourth connection state M4, the fourth terminal T4 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. Further, among the first terminal T1 to the sixth terminal T6, the first terminal T1, the second terminal T2, the third terminal T3, the fifth terminal T5, and the sixth terminal T6, which are not connected to the first reference potential 50, are It is in an open state. In the high frequency band used for transmission and reception of the antenna 10, equivalently, the first terminal T1, the second terminal T2, the third terminal T3, the fifth terminal T5, and the sixth terminal T6 are respectively via the parasitic capacitance Cs. It is connected to the second reference potential 51. As a result, the first terminal T1, the second terminal T2, the third terminal T3, the fifth terminal T5, and the sixth terminal T6 are equally capacitively connected and function as a circuit.
　図１２は、第２実施形態に係るアンテナ整合回路の第５接続状態を模式的に示す等価回路図である。図１２に示すように、第５接続状態Ｍ５では、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第５端子Ｔ５が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の第１端子Ｔ１から第４端子Ｔ４及び第６端子Ｔ６は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１から第４端子Ｔ４及び第６端子Ｔ６は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１から第４端子Ｔ４及び第６端子Ｔ６は、等価的に容量接続されて、回路として機能する。 FIG. 12 is an equivalent circuit diagram schematically showing a fifth connection state of the antenna matching circuit according to the second embodiment. As shown in FIG. 12, in the fifth connection state M5, the fifth terminal T5 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. Further, of the first terminal T1 to the sixth terminal T6, the first terminal T1 to the fourth terminal T4 and the sixth terminal T6 which are not connected to the first reference potential 50 are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the first terminal T1 to the fourth terminal T4 and the sixth terminal T6 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the first terminal T1 to the fourth terminal T4 and the sixth terminal T6 are equivalently connected by capacitance and function as a circuit.
　図１３は、第２実施形態に係るアンテナ整合回路の第６接続状態を模式的に示す等価回路図である。図１３に示すように、第６接続状態Ｍ６では、スイッチ３０Ａの動作により、第１端子Ｔ１から第６端子Ｔ６のうち、第６端子Ｔ６が第１基準電位５０と電気的に接続される。また、第１端子Ｔ１から第６端子Ｔ６のうち、第１基準電位５０と非接続状態の第１端子Ｔ１から第５端子Ｔ５は、開放状態である。アンテナ１０の送受信に使用される高周波帯では、等価的に、第１端子Ｔ１から第５端子Ｔ５は、それぞれ、寄生容量Ｃｓを介して第２基準電位５１に接続される。これにより、第１端子Ｔ１から第５端子Ｔ５は、等価的に容量接続されて、回路として機能する。 FIG. 13 is an equivalent circuit diagram schematically showing a sixth connection state of the antenna matching circuit according to the second embodiment. As shown in FIG. 13, in the sixth connection state M6, the sixth terminal T6 of the first terminal T1 to the sixth terminal T6 is electrically connected to the first reference potential 50 by the operation of the switch 30A. Further, of the first terminal T1 to the sixth terminal T6, the first terminal T1 to the fifth terminal T5 which are not connected to the first reference potential 50 are in an open state. In the high frequency band used for transmission and reception of the antenna 10, the first terminal T1 to the fifth terminal T5 are respectively connected to the second reference potential 51 via the parasitic capacitance Cs. As a result, the first terminal T1 to the fifth terminal T5 are equally capacitively connected and function as a circuit.
　図８から図１３に示すように、スイッチ３０Ａの動作により、第１インダクタ２１、第２インダクタ２２及び第３インダクタ２３と、第１基準電位５０との接続状態が切り替えられる。アンテナ整合回路１Ａは、上述した第１実施形態よりも多くの接続状態を有し、アンテナ特性に応じて適切に周波数を切り替えることができる。 As shown in FIGS. 8 to 13, the connection state of the first inductor 21, the second inductor 22, the third inductor 23 and the first reference potential 50 is switched by the operation of the switch 30A. The antenna matching circuit 1A has more connection states than the above-described first embodiment, and can appropriately switch the frequency according to the antenna characteristics.
　図１４は、第２実施形態に係るアンテナ整合回路の、異なる接続状態ごとの、反射係数と周波数との関係を示すグラフである。図１４のグラフ２に示すように、第１接続状態Ｍ１から第６接続状態Ｍ６のそれぞれで共振周波数が異なる。具体的には、第１接続状態Ｍ１では、アンテナ整合回路１Ａの共振周波数は、２．８ＧＨｚ付近である。第２接続状態Ｍ２では、アンテナ整合回路１Ａの共振周波数は、６．５ＧＨｚ付近である。第３接続状態Ｍ３では、アンテナ整合回路１Ａの共振周波数は、４．４ＧＨｚ付近である。第４接続状態Ｍ４では、アンテナ整合回路１Ａの共振周波数は、３．９ＧＨｚ付近である。第５接続状態Ｍ５では、アンテナ整合回路１Ａの共振周波数は、７．２ＧＨｚ付近である。第６接続状態Ｍ６では、アンテナ整合回路１Ａの共振周波数は、４．５ＧＨｚ付近である。 FIG. 14 is a graph showing the relationship between the reflection coefficient and the frequency for each different connection state of the antenna matching circuit according to the second embodiment. As shown in Graph 2 of FIG. 14, the resonance frequency is different in each of the first connection state M1 to the sixth connection state M6. Specifically, in the first connection state M1, the resonance frequency of the antenna matching circuit 1A is around 2.8 GHz. In the second connection state M2, the resonance frequency of the antenna matching circuit 1A is around 6.5 GHz. In the third connection state M3, the resonance frequency of the antenna matching circuit 1A is around 4.4 GHz. In the fourth connection state M4, the resonance frequency of the antenna matching circuit 1A is around 3.9 GHz. In the fifth connection state M5, the resonance frequency of the antenna matching circuit 1A is around 7.2 GHz. In the sixth connection state M6, the resonance frequency of the antenna matching circuit 1A is around 4.5 GHz.
　図１４に示すように、第１インダクタ２１、第２インダクタ２２、第３インダクタ２３及び第１基準電位５０の接続状態を切り替えることで、アンテナ整合回路１Ａの共振周波数を変更できることが示された。これにより、アンテナ整合回路１Ａは、１つのコモンモードチョークコイル２０Ａで、複数の異なるアンテナ特性を実現できる。なお、第２実施形態では、コモンモードチョークコイル２０Ａの６つの端子と、第１基準電位５０との接続状態を切り替える場合に限定されない。すなわち、スイッチ３０Ａは、６つの端子のうち、少なくとも２つの端子の接続状態を切り替え可能であれば、インピーダンス整合を行うことができる。 As shown in FIG. 14, it was shown that the resonance frequency of the antenna matching circuit 1A can be changed by switching the connection state of the first inductor 21, the second inductor 22, the third inductor 23, and the first reference potential 50. As a result, the antenna matching circuit 1A can realize a plurality of different antenna characteristics with one common mode choke coil 20A. The second embodiment is not limited to the case of switching the connection state between the six terminals of the common mode choke coil 20A and the first reference potential 50. That is, the switch 30A can perform impedance matching as long as the connection state of at least two of the six terminals can be switched.
（第３実施形態）
　図１５は、第３実施形態に係るアンテナ整合回路を模式的に示す回路図である。第３実施形態では、上述した第１実施形態及び第２実施形態とは異なり、第４インダクタ２４を有し、第４インダクタ２４が第１インダクタ２１と直列に接続される構成について説明する。 (Third Embodiment)
FIG. 15 is a circuit diagram schematically showing an antenna matching circuit according to a third embodiment. In the third embodiment, unlike the first embodiment and the second embodiment described above, a configuration in which the fourth inductor 24 is provided and the fourth inductor 24 is connected in series with the first inductor 21 will be described.
　具体的には、図１５に示すように、コモンモードチョークコイル２０Ｂにおいて、第１インダクタ２１と第４インダクタ２４とは、第１端子Ｔ１と第２端子Ｔ２との間で、直列に接続される。第１インダクタ２１の一端側は、第１端子Ｔ１に電気的に接続され、第１インダクタ２１の他端側は、第４インダクタ２４の一端側に電気的に接続される。また、第４インダクタ２４の他端側は、第２端子Ｔ２に電気的に接続される。コモンモードチョークコイル２０Ｂは、上述した第１実施形態と同様に４つの端子を有するが、第１端子Ｔ１と第２端子Ｔ２との間のインダクタンス値が異なる。 Specifically, as shown in FIG. 15, in the common mode choke coil 20B, the first inductor 21 and the fourth inductor 24 are connected in series between the first terminal T1 and the second terminal T2. .. One end side of the first inductor 21 is electrically connected to the first terminal T1, and the other end side of the first inductor 21 is electrically connected to one end side of the fourth inductor 24. Further, the other end side of the fourth inductor 24 is electrically connected to the second terminal T2. The common mode choke coil 20B has four terminals as in the first embodiment described above, but the inductance values between the first terminal T1 and the second terminal T2 are different.
　スイッチ３０Ｂは、上述した第１実施形態と同様に第１端子Ｔ１から第４端子Ｔ４のうち、１つの端子と第１基準電位５０との接続状態を切り替える。 The switch 30B switches the connection state between one terminal of the first terminal T1 to the fourth terminal T4 and the first reference potential 50 in the same manner as in the first embodiment described above.
　図１６は、第３実施形態に係るアンテナ整合回路の第１接続状態を模式的に示す等価回路図である。図１７は、第３実施形態に係るアンテナ整合回路の第２接続状態を模式的に示す等価回路図である。図１８は、第３実施形態に係るアンテナ整合回路の第３接続状態を模式的に示す等価回路図である。図１９は、第３実施形態に係るアンテナ整合回路の第４接続状態を模式的に示す等価回路図である。 FIG. 16 is an equivalent circuit diagram schematically showing a first connection state of the antenna matching circuit according to the third embodiment. FIG. 17 is an equivalent circuit diagram schematically showing a second connection state of the antenna matching circuit according to the third embodiment. FIG. 18 is an equivalent circuit diagram schematically showing a third connection state of the antenna matching circuit according to the third embodiment. FIG. 19 is an equivalent circuit diagram schematically showing a fourth connection state of the antenna matching circuit according to the third embodiment.
　図１６から図１９に示すように、本実施形態では、第１接続状態Ｍ１から第４接続状態Ｍ４のそれぞれで、４つの端子と、第１基準電位５０、第２基準電位５１及び寄生容量Ｃｓとの接続構成は、図２から図５に示す第１実施形態と同様である。つまり、アンテナ整合回路１Ｂは、１つのコモンモードチョークコイル２０Ｂで４種類の接続状態に切り替えることができる。 As shown in FIGS. 16 to 19, in the present embodiment, each of the first connection state M1 to the fourth connection state M4 has four terminals, a first reference potential 50, a second reference potential 51, and a parasitic capacitance Cs. The connection configuration with and from is the same as that of the first embodiment shown in FIGS. 2 to 5. That is, the antenna matching circuit 1B can be switched to four types of connection states by one common mode choke coil 20B.
　ただし、第１端子Ｔ１と第２端子Ｔ２との間で、第１インダクタ２１と第４インダクタ２４とが直列に接続されているので、第１インダクタ２１、第２インダクタ２２及び第４インダクタ２４の結合状態は、第１実施形態とは異なる。これにより、第３実施形態では、第１実施形態とは異なる周波数特性を実現できる。 However, since the first inductor 21 and the fourth inductor 24 are connected in series between the first terminal T1 and the second terminal T2, the first inductor 21, the second inductor 22, and the fourth inductor 24 The binding state is different from that of the first embodiment. As a result, in the third embodiment, it is possible to realize a frequency characteristic different from that of the first embodiment.
　なお、上述したコモンモードチョークコイル２０、２０Ａ、２０Ｂにおいて、端子の数は４又は６に限定されない。端子の数は７以上であってもよい。また、上述した第２実施形態と第３実施形態とを組み合わせてもよい。 The number of terminals in the above-mentioned common mode choke coils 20, 20A and 20B is not limited to 4 or 6. The number of terminals may be 7 or more. Moreover, you may combine the 2nd Embodiment and the 3rd Embodiment described above.
　なお、上記した実施の形態は、本発明の理解を容易にするためのものであり、本発明を限定して解釈するためのものではない。本発明は、その趣旨を逸脱することなく、変更／改良され得るとともに、本発明にはその等価物も含まれる。 It should be noted that the above-described embodiment is for facilitating the understanding of the present invention, and is not for limiting and interpreting the present invention. The present invention can be modified / improved without departing from the spirit thereof, and the present invention also includes an equivalent thereof.
　１、１Ａ、１Ｂ　アンテナ整合回路
　１０　アンテナ
　２０、２０Ａ、２０Ｂ　コモンモードチョークコイル
　２１　第１インダクタ
　２２　第２インダクタ
　２３　第３インダクタ
　２４　第４インダクタ
　３０、３０Ａ、３０Ｂ　スイッチ
　４０　制御回路
　５０　第１基準電位
　５１　第２基準電位
　Ｃｓ　寄生容量
　Ｍ１　第１接続状態
　Ｍ２　第２接続状態
　Ｍ３　第３接続状態
　Ｍ４　第４接続状態
　Ｍ５　第５接続状態
　Ｍ６　第６接続状態
　Ｔ１　第１端子
　Ｔ２　第２端子
　Ｔ３　第３端子
　Ｔ４　第４端子
　Ｔ５　第５端子
　Ｔ６　第６端子
　ＴＳ１、ＴＳ２、ＴＳ３、ＴＳ４　スイッチ側端子 1, 1A, 1B Antenna matching circuit 10 Antenna 20, 20A, 20B Common mode choke coil 21 1st inductor 22 2nd inductor 23 3rd inductor 24 4th inductor 30, 30A, 30B Switch 40 Control circuit 50 1st reference potential 51 2nd reference potential Cs parasitic capacitance M1 1st connection state M2 2nd connection state M3 3rd connection state M4 4th connection state M5 5th connection state M6 6th connection state T1 1st terminal T2 2nd terminal T3 3rd terminal T4 4th terminal T5 5th terminal T6 6th terminal TS1, TS2, TS3, TS4 Switch side terminal

Claims (5)

  1. 　アンテナと、
    　前記アンテナに接続される第１インダクタと、
    　前記第１インダクタとの間に相互インダクタンスを形成する第２インダクタと、
    　前記第１インダクタ及び前記第２インダクタのそれぞれの両端に電気的に接続される複数の端子と、
    　複数の前記端子のうち、少なくとも２つの前記端子と、第１基準電位との接続状態を切り替えるスイッチと、を有し、
    　複数の前記端子のうち、前記第１基準電位と非接続状態の前記端子は、開放状態である
    　アンテナ整合回路。     With the antenna
    The first inductor connected to the antenna and
    A second inductor that forms a mutual inductance with the first inductor,
    A plurality of terminals electrically connected to both ends of the first inductor and the second inductor,
    It has at least two of the terminals and a switch for switching the connection state with the first reference potential.
    Of the plurality of terminals, the terminal that is not connected to the first reference potential is an antenna matching circuit that is in an open state.
  2. 　請求項１に記載のアンテナ整合回路であって、
    　前記第１インダクタ及び前記第２インダクタは、一体型のコモンモードチョークコイルである
    　アンテナ整合回路。     The antenna matching circuit according to claim 1.
    The first inductor and the second inductor are an antenna matching circuit which is an integrated common mode choke coil.
  3. 　請求項１又は請求項２に記載のアンテナ整合回路であって、
    　さらに、第３インダクタを有し、
    　前記第３インダクタは、前記第１インダクタ及び前記第２インダクタの少なくとも一方との間に相互インダクタンスを形成し、
    　前記スイッチは、前記第３インダクタの両端に電気的に接続される端子を含む複数の前記端子のうち、少なくとも２つの前記端子と、前記第１基準電位との接続状態を切り替える
    　アンテナ整合回路。     The antenna matching circuit according to claim 1 or 2.
    In addition, it has a third inductor and
    The third inductor forms a mutual inductance with at least one of the first inductor and the second inductor.
    The switch is an antenna matching circuit that switches the connection state between at least two of the terminals including terminals electrically connected to both ends of the third inductor and the first reference potential.
  4. 　請求項１から請求項３のいずれか１項に記載のアンテナ整合回路であって、
    　さらに、第４インダクタを有し、
    　前記第４インダクタは、前記第１インダクタと直列に接続される
    　アンテナ整合回路。     The antenna matching circuit according to any one of claims 1 to 3.
    In addition, it has a fourth inductor and
    The fourth inductor is an antenna matching circuit connected in series with the first inductor.
  5. 　請求項１から請求項４のいずれか１項に記載のアンテナ整合回路であって、
    　複数の前記端子のうち、前記第１基準電位と非接続状態の前記端子は、等価的に容量成分を介して第２基準電位に接続される
    　アンテナ整合回路。     The antenna matching circuit according to any one of claims 1 to 4.
    Of the plurality of terminals, the terminal that is not connected to the first reference potential is an antenna matching circuit that is equivalently connected to the second reference potential via a capacitance component.
PCT/JP2021/002410 2020-02-07 2021-01-25 Antenna matching circuit WO2021157402A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0457765U (en) * 1990-09-26 1992-05-18
JP3021857U (en) * 1995-08-23 1996-03-12 有限会社今井電機製作所 Shortened vertical and horizontal antenna matching device
WO2017065142A1 (en) * 2015-10-16 2017-04-20 株式会社村田製作所 Antenna circuit and communication device
WO2020005231A1 (en) * 2018-06-27 2020-01-02 Intel IP Corporation Wideband reconfigurable impedance matching network

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0457765U (en) * 1990-09-26 1992-05-18
JP3021857U (en) * 1995-08-23 1996-03-12 有限会社今井電機製作所 Shortened vertical and horizontal antenna matching device
WO2017065142A1 (en) * 2015-10-16 2017-04-20 株式会社村田製作所 Antenna circuit and communication device
WO2020005231A1 (en) * 2018-06-27 2020-01-02 Intel IP Corporation Wideband reconfigurable impedance matching network

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