WO2018180149A1 - Antenna device and electronic instrument - Google Patents

Antenna device and electronic instrument Download PDF

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Publication number
WO2018180149A1
WO2018180149A1 PCT/JP2018/007489 JP2018007489W WO2018180149A1 WO 2018180149 A1 WO2018180149 A1 WO 2018180149A1 JP 2018007489 W JP2018007489 W JP 2018007489W WO 2018180149 A1 WO2018180149 A1 WO 2018180149A1
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WO
WIPO (PCT)
Prior art keywords
coil
circuit
primary
antenna device
conductive member
Prior art date
Application number
PCT/JP2018/007489
Other languages
French (fr)
Japanese (ja)
Inventor
市川　敬一
末定　剛
貴文 那須
Original Assignee
株式会社村田製作所
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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
Priority to JP2018547484A priority Critical patent/JP6428989B1/en
Publication of WO2018180149A1 publication Critical patent/WO2018180149A1/en

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H04B5/48—

Definitions

  • the present invention relates to an antenna device used in near field communication and an electronic apparatus including the antenna device.
  • an antenna device used for an HF band RFID system such as NFC (Near Field Communication) is incorporated.
  • a low inductance part such as a part of a metal casing may be used as a part of a loop antenna.
  • Patent Document 1 discloses an antenna device in which a feeding coil is magnetically coupled to the loop antenna and a feeding circuit is connected to the feeding coil.
  • the loop antenna having a magnetic coupling element such as a transformer in part as a power supply by magnetic field coupling to the entire loop antenna as shown in Patent Document 1 via the magnetic coupling of the magnetic coupling element.
  • a magnetic coupling element such as a transformer in part as a power supply by magnetic field coupling to the entire loop antenna as shown in Patent Document 1
  • a resonant loop in which the radiating element portion and the magnetic coupling element are connected in series is formed. Therefore, a large current also flows through the magnetic coupling element, and there is a problem that it is difficult to downsize the magnetic coupling element from the viewpoint of heat dissipation.
  • an object of the present invention is to provide an antenna device and an electronic device including the antenna device that are intended to simplify a circuit configuration, reduce an occupied area, and improve communication characteristics.
  • the antenna device of the present invention is an antenna device used in near-field communication, and is connected to a communication circuit having a reader / writer function, a primary circuit having a primary coil, a conductive member, and a secondary A secondary circuit having a coil and a secondary capacitor.
  • the primary coil and the secondary coil are magnetically coupled, and the conductive member, the secondary coil, and the secondary capacitor are connected in parallel to each other and have two branch points.
  • the reactance of the current path through the secondary coil is inductive, and the inductance of the secondary coil is larger than the inductance of the conductive member, and the inductance of the conductive member and the secondary side
  • the capacitor constitutes a secondary side resonance circuit. And it couple
  • the conductive member having a low inductance can be matched with the communication circuit with a simple configuration, the conductive member can be effectively used as a magnetically coupled antenna, and the antenna structure can be simplified. Moreover, the current flowing through the conductive member can be increased, and high communication characteristics can be obtained.
  • the primary side circuit further includes a primary side capacitor, and the primary side capacitor is connected in series to the primary coil, and the primary coil and the primary side capacitor constitute a primary side resonance circuit. It is preferable to do.
  • the filter circuit for EMI countermeasures provided between the communication circuit and the primary coil can be simplified, and the number of parts constituting the matching circuit can be reduced, so that it can be easily incorporated into the device.
  • the center frequency of the communication frequency band of the near field communication may be between two resonance frequencies generated by a coupled resonance circuit configured by coupling a primary side resonance circuit and a secondary side resonance circuit. preferable.
  • the antenna device further includes a housing having a housing conductor portion, and a part or all of the conductive member is the housing conductor portion.
  • the antenna device in a state of being incorporated in the electronic base device can be reduced in size.
  • the antenna device further includes a multilayer chip component, and the primary coil and the secondary coil are formed integrally with the multilayer chip component, and the multilayer chip component preferably has a magnetic layer.
  • the primary coil and the secondary coil can be reduced in size, and a small antenna device can be configured. Further, the primary coil and the secondary coil can be stably coupled with a high coupling coefficient, and an antenna device with stable characteristics can be configured.
  • the primary circuit further includes an inductor that blocks high-frequency noise.
  • the electronic device of the present invention includes an antenna device used in near-field communication and a housing having a housing conductor, and the antenna device is A primary circuit having a primary coil connected to a communication circuit having a reader / writer function, and a secondary circuit having a conductive member, a secondary coil, and a secondary capacitor are provided.
  • the primary coil and the secondary coil are magnetically coupled, and the conductive member, the two coils, and the secondary capacitor are connected in parallel to each other and have two branch points.
  • the reactance of the current path through the secondary coil is inductive, and the inductance of the secondary coil is larger than the inductance of the conductive member, and the inductance of the conductive member and the secondary side
  • the capacitor constitutes a secondary side resonance circuit. And it is characterized in that it is magnetically coupled with a communication partner by a magnetic field generated by a current flowing through the conductive member.
  • an electronic device having a small-sized antenna device for near-field communication with high communication characteristics is configured.
  • an antenna device and an electronic device equipped with the antenna device with a simplified circuit configuration, a reduced occupied area, and improved communication characteristics.
  • FIG. 1 is a circuit diagram of an antenna device 101A according to the first embodiment.
  • FIG. 2 is a circuit diagram of another antenna device 101B according to the first embodiment.
  • FIG. 3 is an external perspective view of the magnetic coupling element 3.
  • FIG. 4 is an enlarged view of a portion where the primary coil L1 and the secondary coil L2 are formed inside the magnetic coupling element 3.
  • FIG. 5 is a cross-sectional view of the magnetic coupling element 3.
  • FIG. 6 is a circuit diagram of an antenna device 102A according to the second embodiment.
  • FIG. 7 is a circuit diagram of another antenna device 102B according to the second embodiment.
  • Figure 8 is a graph showing the frequency characteristic of the current i A flowing through the current i1 and the conductive member 20 flowing through the primary coil L1.
  • FIG. 1 is a circuit diagram of an antenna device 101A according to the first embodiment.
  • FIG. 2 is a circuit diagram of another antenna device 101B according to the first embodiment.
  • FIG. 3 is an external perspective view of the
  • FIG. 9 is a schematic cross-sectional view of an antenna device provided in an electronic apparatus according to the third embodiment.
  • FIG. 10 is a perspective view showing the shape of the metal parts 20F and 21F of the housing.
  • FIG. 11 is a perspective view illustrating an example of a housing metal part having a shape different from that of the metal part of the housing illustrated in FIG. 10.
  • 12 is a perspective view showing an example of a housing metal part having a shape different from that of the metal part of the housing shown in FIG.
  • FIG. 13 is a plan view of an antenna device 104A provided in an electronic apparatus according to the fourth embodiment.
  • FIG. 14 is a plan view of an antenna device 104B provided in another electronic apparatus according to the fourth embodiment.
  • FIG. 15 is a circuit diagram of the magnetic coupling element according to the fifth embodiment.
  • FIG. 16 is a circuit diagram of another magnetic coupling element according to the fifth embodiment. 17 is a cross-sectional view of the magnetic coupling element shown in FIG.
  • FIG. 18 is a circuit diagram of the antenna device 106 according to the sixth embodiment.
  • FIG. 19 is a circuit diagram of the antenna device 107 of the seventh embodiment.
  • FIG. 20 is a circuit diagram of the antenna device 108 of the eighth embodiment.
  • the “antenna device” is an antenna that radiates magnetic flux.
  • the antenna device is an antenna used for near-field communication using magnetic field coupling with an antenna on the communication partner side, and is used for communication such as NFC (Near field communication).
  • the antenna device is used in the HF band, for example, and is used particularly at a frequency near 13.56 MHz or 13.56 MHz. Since the size of the antenna device is sufficiently smaller than the wavelength ⁇ at the used frequency, the electromagnetic wave radiation characteristics are poor in the used frequency band.
  • the length of the coil conductor when the coil conductor of the coil antenna provided in the antenna device described later is extended is ⁇ / 10 or less.
  • the “wavelength” here is an effective wavelength considering the wavelength shortening effect due to the dielectric property and permeability of the substrate on which the antenna is formed.
  • Both ends of the coil conductor of the coil antenna are connected to a power feeding circuit that operates the used frequency band (HF band, particularly around 13.56 MHz). Therefore, the coil conductor has a substantially uniform current flowing along the coil conductor, that is, in the direction in which the current flows, and the length of the coil conductor is equal to or greater than the wavelength. Current distribution along the line is unlikely to occur.
  • HF band used frequency band
  • FIG. 1 is a circuit diagram of an antenna device 101A according to the first embodiment.
  • This antenna device 101A is an antenna device used in near-field communication, and is used, for example, as a reader / writer in an RFID system that performs NFC communication. Alternatively, it is used for an electronic device having a reader / writer function.
  • the antenna device 101A includes a primary side circuit 1 and a secondary side circuit 2 connected to the transceiver IC9.
  • the transceiver IC 9 has a reader / writer control function.
  • the primary circuit 1 has a primary coil L1.
  • the secondary side circuit 2 includes a conductive member 20, a secondary coil L2, and a secondary side capacitor C2.
  • an inductor L20 represents the inductance by the conductive member 20 as a circuit element.
  • This conductive member is, for example, a housing conductor part of an electronic device that is substantially a one-turn loop antenna.
  • the transceiver IC 9 is an example of the “communication circuit” according to the present invention.
  • the primary coil L1 and the secondary coil L2 are magnetically coupled to each other. That is, the magnetic coupling element (transformer) 3 is comprised by the primary coil L1 and the secondary coil L2.
  • the conductive member 20, the secondary coil L2, and the secondary capacitor C2 are connected in parallel to each other and have two branch points.
  • the inductance of the conductive member 20 and the secondary side capacitor C2 constitute a secondary side resonance circuit RC2.
  • the reactance of the current path CP of the secondary coil L2 is inductive when viewed from the two branch points (connection points) CN1 and CN2 of the parallel connection.
  • connection points connection points
  • FIG. 1 only the coil L2 is inserted into the current path CP, which is inductive.
  • the inductive reactance of the circuit when the secondary coil L2 is viewed from the branch points CN1 and CN2 is represented by ⁇ L, and the capacitive reactance is represented by 1 / ⁇ C.
  • Inductivity is in a relationship of ⁇ L> 1 / ⁇ C.
  • the inductance of the secondary coil L2 is larger than the inductance of the conductive member 20. That represents the inductance of the secondary coil L2 by L2, to represent the inductance of the antenna loop of the conductive member 20 in L A, L2> is L A, that is, the relationship of L A / L2 ⁇ 1.
  • the inductor L20 by the conductive member 20 and the secondary side capacitor C2 are connected in parallel to the secondary coil L2, and the secondary by the inductor L20 by the conductive member 20 and the secondary side capacitor C2.
  • a side resonance circuit RC2 is configured. The operation of the secondary side resonance circuit RC2 is as follows.
  • the inductance of the secondary coil L2 is larger than that of the inductor L20 made of the conductive member 20, a current easily flows from the secondary coil L2 to the inductor L20. Therefore, the current i A flowing through the secondary side resonance circuit RC2 is larger than the current i2 flowing through the secondary coil L2.
  • the current i A flowing through the secondary side resonance circuit RC2 is a resonance current, it can be a large current according to the Q value of the secondary side resonance circuit RC2, as will be described later. Furthermore, by increasing the Q value of the secondary side resonance circuit RC2 (for example, setting the Q value to 5 or more), energy consumption in the secondary side resonance circuit RC2 can be suppressed.
  • the impedance characteristic (for example, resonance frequency) near the drive frequency of the secondary side resonance circuit RC2 can be determined mainly by the characteristics of the conductive member 20 and the secondary side capacitor C2.
  • the drive frequency ⁇ is set close to the resonance frequency ⁇ A of the antenna loop and the secondary capacitor C2, so if the first term of the denominator is ignored as ⁇ A , the current amplification factor is expressed by the following equation.
  • the current flowing through the conductive member 20 is amplified by about Q A times the current flowing through the secondary coil L2.
  • the coupling coefficient k between the primary coil L1 and the secondary coil L2 is less than 1, and more preferably 0.4 or more and 0.9 or less.
  • the leakage inductance of the magnetic coupling element 3 is necessary.
  • the self-inductance of the secondary coil L2 is 5 ⁇ H, for example, and the self-inductance of the primary coil L1 is 2 ⁇ H, for example.
  • Current flowing through the secondary side resonance circuit RC2 is diverted in accordance with the inverse ratio of the inductance L A of the self-inductance and the conductive member 20 of the secondary coil L2.
  • the self-inductance of the secondary coil L2 is preferably an inductance L A example sufficiently larger than 0.05 ⁇ H the conductive member 20 (at least 5 times or more).
  • the increasing the self-inductance of the secondary coil L2 since the possible to reduce the size of the magnetic coupling element 3 is a relation of trade-off, for example, it is kept at about 5 ⁇ H 100 times the L A preferable.
  • the self inductance of the primary coil L1 is made smaller than the self inductance of the secondary coil L2.
  • the self-inductance of the secondary coil L2 is 5 ⁇ H, for example, and the self-inductance of the primary coil L1 is 2 ⁇ H, for example. This allows the necessary current to be drawn from the transceiver IC9.
  • the magnitude relationship between L1 and L2 may change depending on the specifications of the transceiver IC.
  • FIG. 2 is a circuit diagram of another antenna device 101B according to the first embodiment.
  • the configuration of the secondary circuit 2 is different from the antenna device 101A shown in FIG.
  • the primary side circuit 1 is the same as the primary side circuit 1 of the antenna device 101A, in FIG. 2, the transceiver IC is represented as a high frequency voltage source 9E.
  • the parasitic capacitance Cs generated in the secondary coil L2 is illustrated.
  • the capacitor C21 is provided in the current path CP of the secondary coil L2.
  • the reactance of the current path CP is set to be inductive.
  • the magnetic coupling element 3 is comprised by the primary coil L1 and the secondary coil L2. Further, a ⁇ -type capacitive coupling circuit 4 is configured by the parasitic capacitance Cs, the capacitor C21, and the secondary side capacitor C2.
  • the parasitic capacitance Cs may increase due to the structure of the secondary coil L2.
  • the conductors come close to each other and the parasitic capacitance increases, and the influence of the parasitic capacitance cannot be ignored.
  • the resonance frequency characteristic of the secondary side resonance circuit RC2 becomes steep or the loss increases due to the influence of the parasitic capacitance Cs. There is a case to do. This is because the capacitive coupling circuit 4 is configured.
  • the reactance of the current path CP of the secondary coil L2 is made inductive by increasing the capacitance of the series capacitor C21, the influence of the parasitic capacitance can be reduced, and the secondary resonance circuit RC2 and the magnetic coupling element 3 (2 The coupling with the secondary coil L2) can be enhanced.
  • FIG. 3 is an external perspective view of the magnetic coupling element 3.
  • FIG. 4 is an enlarged view of a portion where the primary coil L1 and the secondary coil L2 in the magnetic coupling element 3 are formed, and is particularly shown extended in the stacking direction.
  • FIG. 5 is a cross-sectional view of the magnetic coupling element 3.
  • the magnetic coupling element 3 is a rectangular parallelepiped laminated chip component, and a terminal on which both ends of the primary coil L1 are conductive and a terminal on which both ends of the secondary coil L2 are conductive are formed on the bottom surface.
  • the magnetic coupling element 3 is surface-mounted on a circuit board using these terminals as mounting terminals.
  • the magnetic coupling element 3 is an element in which a primary coil L1 and a secondary coil L2 are integrally formed as a multilayer chip component.
  • the magnetic coupling element 3 has a magnetic layer in order to increase the inductance.
  • the formation layer of the primary coil L1, the secondary coil L2, and the layer between the primary coil L1 and the secondary coil L2 are magnetic ferrite layers, and the other layers are nonmagnetic ferrite layers.
  • the structure which does not form a nonmagnetic layer may be sufficient.
  • the loop pattern or a partial pattern thereof is a coil conductor pattern, and the pattern extending in the vertical direction is an interlayer connection conductor.
  • the primary coil L1 includes a plurality of primary coil conductor patterns L11, L12, L13, L14, L15, and L16 and interlayer connection conductors that connect these layers.
  • the secondary coil L2 includes a plurality of secondary coil conductor patterns L21, L22, L23, and L24, and interlayer connection conductors that connect these layers.
  • the primary coil L1 is a helical coil having about 5 turns
  • the secondary coil L2 is a helical coil having about 4 turns.
  • the primary coil L1 and the secondary coil L2 are laminated close to each other, and the coil openings of the primary coil L1 and the secondary coil L2 are overlapped, and the primary coil L1 is wound.
  • the rotation axis and the winding axis of the secondary coil L2 are in a coaxial relationship.
  • FIG. 6 is a circuit diagram of an antenna device 102A according to the second embodiment.
  • FIG. 7 is a circuit diagram of another antenna device 102B according to the second embodiment. In either case, the configuration of the primary circuit 1 is different from the example shown in FIG.
  • the antenna device 102A shown in FIG. 6 includes a primary side circuit 1 and a secondary side circuit 2 connected to the transceiver IC9.
  • the transceiver IC 9 has a transmission signal output port Tx and a reception signal input port Rx.
  • the primary side circuit 1 has a primary coil L1, primary side capacitors C11 and C12, and inductors Lf1 and Lf2.
  • a primary side resonance circuit RC1 is configured by the primary coil L1, the inductors Lf1 and Lf2, and the primary side capacitors C11 and C12.
  • the impedance viewed from the transceiver IC9 can be set to a predetermined impedance (for example, an impedance of 20 ⁇ to 80 ⁇ or less), and thereby impedance matching between the transceiver IC9 and the antenna Can be planned.
  • a predetermined impedance for example, an impedance of 20 ⁇ to 80 ⁇ or less
  • the primary side circuit 1 has a primary coil L1 and a primary side capacitor C10.
  • a primary side resonance circuit RC1 is configured by the primary coil L1 and the primary side capacitor C10.
  • Other configurations are the same as those of the antenna device shown in FIG. 6 or FIG.
  • the transmission signal output port Tx of the transceiver IC 9 is a balanced circuit, one end of the primary coil L1 may be connected to the ground conductor in the case of an unbalanced circuit.
  • the primary side resonance circuit RC1 and the secondary side resonance circuit RC2 are coupled to form one coupled resonance circuit.
  • the communication frequency of near-field communication is between two resonance frequencies generated by this coupled resonance circuit.
  • the inductors Lf1 and Lf2 block high frequency noise including harmonic components of the normal mode voltage and the common mode voltage superimposed on the two Tx ports of the transceiver IC9. These inductors are basically unnecessary, but may be added as necessary when further reduction of high frequency noise is desired. Usually, it is set to a value smaller than the inductance of the primary coil L1.
  • FIG. 8 is a diagram showing frequency characteristics of the current i1 flowing through the primary coil L1 and the current iA flowing through the conductive member 20. Both show bimodality having peaks at frequencies f1 and f2.
  • the two peak frequencies f1 and f2 are resonance frequencies of a coupled resonance circuit generated by coupling the primary side resonance circuit RC1 and the secondary side resonance circuit RC2.
  • the resonance frequencies of the primary side resonance circuit RC1 and the secondary side resonance circuit RC2 are substantially equal to the communication frequency hop, but when they are coupled, the two peak frequencies are separated according to the coupling coefficient. Since the bimodality is not shown when the coupling coefficient is 1, the coupling coefficient k is set to 0.4 or more and 0.9 or less, for example, as described above.
  • the coupled resonant circuit configured by coupling the primary side resonant circuit RC1 and the secondary side resonant circuit RC2 exhibits bandpass characteristics.
  • the high frequency noise component generated in the transceiver IC 9 is attenuated when passing through the coupled resonance circuit, and is not easily radiated from the conductive member functioning as an antenna. That is, since the coupled resonant circuit exhibits filter characteristics, the filter circuit for EMI countermeasures provided between the transceiver IC 9 and the magnetic coupling element 3 can be simplified, and the number of parts of the matching circuit can be reduced, so that it can be easily incorporated into equipment. .
  • FIG. 9 is a schematic cross-sectional view of an antenna device provided in an electronic device.
  • the housing includes metal parts 20F and 21F.
  • the metal portion 20F corresponds to a “conductive member” according to the present invention.
  • FIG. 10 is a perspective view showing the shapes of the metal portions 20F and 21F of the casing.
  • the metal part 20F is located at one end of a smartphone, for example.
  • the transceiver IC 9, the primary side capacitors C11 and C12, the magnetic coupling element 3, and the secondary side capacitor C2 are formed on the circuit board 5, and the circuit board 5 is accommodated in the housing.
  • One end of the secondary capacitor C2 is connected to the circuit ground, and the other end is connected to a part of the metal portion 20F of the housing via a pin terminal (probe pin) or the like.
  • the other part of the metal part 20F is connected to the ground conductor of the circuit board 5 via another pin terminal (probe pin) or the like.
  • FIG. 11 and FIG. 12 are perspective views showing examples of a case metal part having a shape different from the metal part of the case shown in FIG.
  • the housing metal part 20 ⁇ / b> F is not formed as a flat plate but is formed and connected to both ends in the X-axis direction and one end in the Y-axis direction in FIG. 11.
  • the housing metal part 20 ⁇ / b> F is a U-shaped (U-shaped) conductor as viewed from the Y direction.
  • the metal case 20F can be used as a part of the loop antenna.
  • FIG. 13 is a plan view of the antenna device 104A provided in the electronic apparatus.
  • This antenna device 104A includes a loop conductor 20L.
  • the loop conductor 20L corresponds to a “conductive member” according to the present invention.
  • FIG. 14 is a plan view of the antenna device 104B provided in the electronic apparatus.
  • This antenna device 104B includes loop conductors 20L1 and 20L2.
  • the loop conductors 20L1 and 20L2 correspond to “conductive members” according to the present invention.
  • the loop conductors 20L, 20L1, and 20L2 are conductor patterns formed on, for example, a circuit board or a casing. As described above, the conductor formed with a pattern may be used as the “conductive member”.
  • each of these loop conductors 20L1 and 20L2 can act as a loop antenna. This improves the degree of freedom of the communication range.
  • the two loop conductors 20L1 and 20L2 are arranged on the same surface, but the two loop conductors may be formed on the front and back of the substrate.
  • Two loop conductors may be arranged three-dimensionally.
  • one loop conductor may be formed on the front surface or the back surface of the housing or the substrate, and the other loop conductor may be formed on the side surface of the housing or the substrate.
  • the two loop conductors 20L1 and 20L2 are connected in parallel, but they may be connected in series. Three or more loop conductors may be provided.
  • FIG. 15 is a circuit diagram of the magnetic coupling element of the fifth embodiment.
  • the midpoint of the primary coil L1 is connected to the ground. According to this configuration, high-frequency noise (particularly common mode noise component) generated with the switching operation of the transceiver IC is reduced. Note that the output circuit of the transceiver IC is assumed to be a balanced circuit.
  • FIG. 16 is a circuit diagram of another magnetic coupling element according to the fifth embodiment.
  • FIG. 17 is a cross-sectional view of this magnetic coupling element.
  • the primary coil L1 and the secondary coil L2 are helical conductor patterns formed in a laminated body of magnetic ferrite, like the magnetic coupling elements shown in FIGS. Between the formation layer of the primary coil L1 and the formation layer of the secondary coil L2, the layer of the shield conductor SC which shields between those conductor patterns is provided.
  • a ground terminal TG is formed on the lower surface (mounting surface) of the laminate, and the shield conductor SC is a ground terminal. Connected to TG.
  • FIG. 18 is a circuit diagram of the antenna device 106 of the sixth embodiment.
  • the transceiver IC 9 connected to the antenna device 106 has two Rx terminals for differentially receiving received signals. Both ends of the primary coil L1 are connected to the two Rx terminals.
  • the received signal is differentially input from the primary coil L1 to the transceiver IC9, it is less susceptible to common mode noise and increases the SNR (signal-to-noise ratio) of the received signal. It is done.
  • FIG. 19 is a circuit diagram of the antenna device 107 of the seventh embodiment.
  • the transceiver IC 9 connected to the antenna device 107 has a terminal for outputting a control signal for adjusting the resonance frequency of the secondary side resonance circuit RC2.
  • the secondary side resonance circuit RC2 includes an inductor L20, a secondary side capacitor C2, and a variable capacitance element C20.
  • variable capacitance element C20 The capacitance of the variable capacitance element C20 is determined according to the control signal given from the transceiver IC9.
  • the variable capacitance element C20 includes a DA converter circuit including a resistance circuit that converts a control signal of a plurality of bits into an analog voltage signal, and a ferroelectric capacitor to which the analog voltage is applied.
  • the resonance frequency of the secondary side resonance circuit RC2 is actively optimized even if there is a variation in the capacitance of the secondary side capacitor C2 or a change in the resonance frequency characteristics due to the proximity of the metal to the antenna device. It becomes. Therefore, a decrease in communication distance can be suppressed.
  • FIG. 20 is a circuit diagram of the antenna device 108 of the eighth embodiment.
  • the transceiver IC 9 connected to the antenna device 108 is a single-ended transceiver IC.
  • the magnetic coupling element 3 is an autotransformer type element and includes a primary coil L1 and secondary coils L21 and L22. However, the primary coil L1 and the secondary coil L21 are the same coil.
  • the primary side circuit 1 has a primary coil L1 and a primary side capacitor C10.
  • a primary side resonance circuit is configured by the primary coil L1 and the primary side capacitor C10.
  • the inductor Lf blocks high frequency noise including harmonic components superimposed on the Tx port of the transceiver IC9.
  • the secondary circuit 2 includes a conductive member 20, secondary coils (L21, L22), and a secondary capacitor C2.
  • the magnetic coupling element 3 may be an autotransformer element.
  • the insulation type transformer structure shown so far may be used.
  • the communication antenna device has been mainly described.
  • the antenna device of the present invention is mixedly mounted on an electronic device including a circuit used in a wireless power transmission system that uses a lower frequency band than NFC. May be.
  • the NFC circuit (transceiver IC 9 or the like) can be used even when the antenna device receives a high-frequency magnetic field (eg, 6.78 MHz) of the wireless power transmission system. Destruction can be prevented.
  • the magnetic coupling element having the transformer structure in which the coil pattern is formed in the laminated body is shown.
  • the magnetic coupling element of the present invention is not limited to this, and a winding type transformer may be used. Good.
  • all the layers of the laminate constituting the magnetic coupling element may be magnetic layers, or all the layers may be nonmagnetic layers.
  • the reception signal is input to the transceiver IC 9 from the secondary side of the magnetic coupling element 3.
  • an impedance matching circuit such as a resistor or a capacitor
  • the casing metal portion 20F may have any shape as long as it is a metal portion constituting the casing, such as the shape shown in FIGS. Is not limited to). Moreover, it is not necessary to be a single member, and it may be a metal part of a housing constituted by a plurality of members.
  • the antenna device and the electronic device in the communication system mainly using magnetic field coupling such as NFC have been described.
  • the antenna device and the electronic device in the above-described embodiment are contactless using magnetic field coupling.
  • the present invention can be similarly applied to a power transmission system (electromagnetic induction method, magnetic field resonance method).
  • the antenna device in the above-described embodiment is used as a power receiving antenna device of a power receiving device of a magnetic resonance type non-contact power transmission system used in the HF band, particularly in the vicinity of 6.78 MHz or 6.78 MHz. It can be applied as an antenna device.
  • both ends of the coil conductor included in the coil antenna of the antenna device are connected to a power reception circuit or a power transmission circuit that operates a used frequency band (HF band, particularly around 6.78 MHz).
  • the antenna device functions as a power receiving antenna device or a power transmitting antenna device.
  • the power receiving circuit includes, for example, a matching circuit, a smoothing circuit, a DC / DC converter, and the like to supply power from the power receiving coil antenna to a load (secondary battery, etc.). These circuits are connected to the power receiving coil antenna. Cascaded between load.
  • the power transmission circuit includes a rectifier circuit, a smoothing circuit, a switch circuit that functions as a DC / AC inverter, and the like for supplying power from the commercial power source to the power transmission coil antenna. Are connected in cascade.

Abstract

An antenna device (101A) comprising: a primary-side circuit (1) that is connected to a transceiver (IC9) having a reader/writer function, and has a primary coil (L1); and a secondary-side circuit (2) that has an electrically conductive member (20), a secondary coil, and a secondary-side capacitor (C2). Magnetic field coupling is carried out for the primary coil (L1) and the secondary coil (L2). Each of the electrically conductive member (20), the secondary coil (L2), and the secondary-side capacitor (C2) is connected in parallel, and as seen from two branch points (CN1, CN2) of the parallel connection, the reactance of a current path (CP) passing through the secondary coil (L2) is inductive, and the inductance of the secondary coil (L2) is greater than the inductance of the electrically conductive member (20). The inductance of the electrically conductive member (20) and the secondary-side capacitor (C2) constitute a secondary-side resonance circuit (RC2).

Description

アンテナ装置および電子機器ANTENNA DEVICE AND ELECTRONIC DEVICE
　本発明は、近傍界通信で用いられるアンテナ装置およびそれを備える電子機器に関する。 The present invention relates to an antenna device used in near field communication and an electronic apparatus including the antenna device.
　所謂スマートフォンのような小型の電子機器においては、ＮＦＣ(Near Field Communication)などのＨＦ帯ＲＦＩＤシステムに用いられるアンテナ装置が内蔵されている。このＨＦ帯ＲＦＩＤシステムで使われるアンテナ装置を電子機器に設けるために、金属筐体の一部などの低いインダクタンス部をループアンテナの一部として利用されることがある。 In a small electronic device such as a so-called smartphone, an antenna device used for an HF band RFID system such as NFC (Near Field Communication) is incorporated. In order to provide an electronic device with an antenna device used in this HF band RFID system, a low inductance part such as a part of a metal casing may be used as a part of a loop antenna.
　特許文献１には、上記ループアンテナに給電コイルを磁界結合させ、その給電コイルに給電回路を接続するようにしたアンテナ装置が示されている。 Patent Document 1 discloses an antenna device in which a feeding coil is magnetically coupled to the loop antenna and a feeding circuit is connected to the feeding coil.
国際公開第２０１４／０９８０２４号International Publication No. 2014/098024
　特許文献１に示されているような、金属筐体の一部などの低いインダクタンス部をループアンテナの一部として利用するアンテナにおいて、金属筐体の一部とキャパシタが直列に接続されたＬＣ共振ループに磁界結合を介して給電する構成では、トランシーバＩＣと給電コイルとの間にＥＭＩ対策用のフィルタ回路が必要になることが多い。これらのことに起因して、アンテナ装置の構造が複雑になり、占有面積が大きくなるという問題があった。 LC resonance in which a part of a metal casing and a capacitor are connected in series in an antenna that uses a low inductance part such as a part of a metal casing as a part of a loop antenna as shown in Patent Document 1 In a configuration in which power is supplied to the loop via magnetic field coupling, a filter circuit for EMI countermeasures is often required between the transceiver IC and the power supply coil. For these reasons, there is a problem that the structure of the antenna device becomes complicated and the occupied area becomes large.
　また、特許文献１に示されているような、ループアンテナ全体に磁界結合による給電を行う構成でなく、トランス等の磁界結合素子を一部に有するループアンテナにおいて、磁界結合素子の磁界結合を介してループアンテナに給電を行う構成の場合、放射特性の向上のためにループアンテナに流れる電流を大きくしようとすると、放射素子部分と磁界結合素子とが直列に接続された共振ループを構成することになるため、磁界結合素子にも大電流が流れることになってしまい、この磁界結合素子を放熱等の観点から小型化することが難いという問題もあった。 Further, in the loop antenna having a magnetic coupling element such as a transformer in part as a power supply by magnetic field coupling to the entire loop antenna as shown in Patent Document 1, via the magnetic coupling of the magnetic coupling element. In the case of a configuration in which power is supplied to the loop antenna, if an attempt is made to increase the current flowing through the loop antenna in order to improve the radiation characteristics, a resonant loop in which the radiating element portion and the magnetic coupling element are connected in series is formed. Therefore, a large current also flows through the magnetic coupling element, and there is a problem that it is difficult to downsize the magnetic coupling element from the viewpoint of heat dissipation.
　そこで、本発明の目的は、回路構成の簡略化、占有面積の削減および通信特性の向上を図ったアンテナ装置およびそれを備える電子機器を提供することにある。 Accordingly, an object of the present invention is to provide an antenna device and an electronic device including the antenna device that are intended to simplify a circuit configuration, reduce an occupied area, and improve communication characteristics.
（１）本発明のアンテナ装置は、近傍界通信で用いられるアンテナ装置であって、リーダーライター機能を有する通信回路に接続され、１次コイルを有する１次側回路と、導電性部材と２次コイルと２次側キャパシタとを有する２次側回路と、を備える。１次コイルと２次コイルとは磁界結合し、導電性部材、２次コイルおよび２次側キャパシタは、互いに並列接続され、２つの分岐点を有する。この並列接続の２つの分岐点からみて、２次コイルを通る電流経路のリアクタンスは誘導性であり、２次コイルのインダクタンスは導電性部材のインダクタンスよりも大きく、導電性部材のインダクタンスと２次側キャパシタとは２次側共振回路を構成する。そして、導電性部材に流れる電流により発生する磁界によって通信相手と磁界結合する。 (1) The antenna device of the present invention is an antenna device used in near-field communication, and is connected to a communication circuit having a reader / writer function, a primary circuit having a primary coil, a conductive member, and a secondary A secondary circuit having a coil and a secondary capacitor. The primary coil and the secondary coil are magnetically coupled, and the conductive member, the secondary coil, and the secondary capacitor are connected in parallel to each other and have two branch points. In view of the two branch points of this parallel connection, the reactance of the current path through the secondary coil is inductive, and the inductance of the secondary coil is larger than the inductance of the conductive member, and the inductance of the conductive member and the secondary side The capacitor constitutes a secondary side resonance circuit. And it couple | bonds with a communicating party magnetic field with the magnetic field generated by the electric current which flows into an electroconductive member.
　上記構成により、簡素な構成で、インダクタンスの低い導電性部材と通信回路との整合が図れ、上記導電性部材を磁界結合アンテナとして有効に利用でき、アンテナ構造を簡素化できる。また、上記導電性部材に流れる電流を大きくでき、高い通信特性が得られる。 With the above configuration, the conductive member having a low inductance can be matched with the communication circuit with a simple configuration, the conductive member can be effectively used as a magnetically coupled antenna, and the antenna structure can be simplified. Moreover, the current flowing through the conductive member can be increased, and high communication characteristics can be obtained.
（２）前記１次側回路は１次側キャパシタを更に有し、この１次側キャパシタは、１次コイルに直列接続され、１次コイルと１次側キャパシタとで１次側共振回路を構成することが好ましい。 (2) The primary side circuit further includes a primary side capacitor, and the primary side capacitor is connected in series to the primary coil, and the primary coil and the primary side capacitor constitute a primary side resonance circuit. It is preferable to do.
　上記構成により、通信回路と１次コイルとの間に設けるＥＭＩ対策用のフィルタ回路を簡略化でき、整合回路を構成する部品の数を減らすことにより、機器に組み込み易くなる。 With the above configuration, the filter circuit for EMI countermeasures provided between the communication circuit and the primary coil can be simplified, and the number of parts constituting the matching circuit can be reduced, so that it can be easily incorporated into the device.
（３）前記近傍界通信の通信周波数帯の中心周波数は、１次側共振回路と２次側共振回路とが結合して構成される結合共振回路により生じる２つの共振周波数の間にあることが好ましい。 (3) The center frequency of the communication frequency band of the near field communication may be between two resonance frequencies generated by a coupled resonance circuit configured by coupling a primary side resonance circuit and a secondary side resonance circuit. preferable.
　上記構成により、結合共振回路を帯域通過型のフィルタとして機能させることができ、通信回路が発生する高周波ノイズ成分、および、スイッチングに伴う高調波ノイズ成分の漏洩を抑制できる。また、上記導電性部材に流す電流（＝漏洩磁界）の高調波成分を含む高周波ノイズ成分を減衰させることができる。 With the above configuration, the coupled resonant circuit can function as a band-pass filter, and leakage of high-frequency noise components generated by the communication circuit and harmonic noise components accompanying switching can be suppressed. Further, it is possible to attenuate high frequency noise components including harmonic components of current (= leakage magnetic field) flowing through the conductive member.
（４）アンテナ装置は、筐体導体部を有する筐体を更に備え、導電性部材の一部または全部は筐体導体部であることが好ましい。 (4) It is preferable that the antenna device further includes a housing having a housing conductor portion, and a part or all of the conductive member is the housing conductor portion.
　上記構成により、電子機器の筐体の一部をループアンテナとして利用できるので、電子基機器に組み込まれた状態でのアンテナ装置を小型化できる。 With the above configuration, since a part of the casing of the electronic device can be used as a loop antenna, the antenna device in a state of being incorporated in the electronic base device can be reduced in size.
（５）アンテナ装置は、積層型チップ部品を更に有し、１次コイルと２次コイルは、積層型チップ部品に一体的に形成され、この積層型チップ部品は磁性層を有することが好ましい。 (5) The antenna device further includes a multilayer chip component, and the primary coil and the secondary coil are formed integrally with the multilayer chip component, and the multilayer chip component preferably has a magnetic layer.
　上記構成により、１次コイルおよび２次コイルを小型化でき、小型のアンテナ装置が構成できる。また、１次コイルと２次コイルとを高い結合係数で且つ安定的に結合させることができ、特性の安定したアンテナ装置が構成できる。 With the above configuration, the primary coil and the secondary coil can be reduced in size, and a small antenna device can be configured. Further, the primary coil and the secondary coil can be stably coupled with a high coupling coefficient, and an antenna device with stable characteristics can be configured.
（６）前記１次側回路は、高周波ノイズを遮断するインダクタを更に有することが好ましい。 (6) It is preferable that the primary circuit further includes an inductor that blocks high-frequency noise.
　上記構成により、通信回路の入出力端に重畳される高調波成分を含む高周波ノイズが抑制されて、通信回路から発生する高周波成分、および、スイッチングに伴う高調波ノイズのアンテナへの漏洩をさらに低減できる。 With the above configuration, high-frequency noise including harmonic components superimposed on the input and output ends of the communication circuit is suppressed, and leakage of high-frequency components generated from the communication circuit and harmonic noise associated with switching to the antenna is further reduced. it can.
（７）本発明の電子機器は、近傍界通信で用いられるアンテナ装置、および筐体導体部を有する筐体を備え、前記アンテナ装置は、
　リーダーライター機能を有する通信回路に接続され、１次コイルを有する１次側回路と、導電性部材と２次コイルと２次側キャパシタとを有する２次側回路と、を備える。１次コイルと２次コイルとは磁界結合し、導電性部材、２コイルおよび２次側キャパシタは、互いに並列接続され、２つの分岐点を有する。この並列接続の２つの分岐点からみて、２次コイルを通る電流経路のリアクタンスは誘導性であり、２次コイルのインダクタンスは導電性部材のインダクタンスよりも大きく、導電性部材のインダクタンスと２次側キャパシタとは２次側共振回路を構成する。そして、導電性部材に流れる電流により発生する磁界によって通信相手と磁界結合することを特徴とする。 (7) The electronic device of the present invention includes an antenna device used in near-field communication and a housing having a housing conductor, and the antenna device is
A primary circuit having a primary coil connected to a communication circuit having a reader / writer function, and a secondary circuit having a conductive member, a secondary coil, and a secondary capacitor are provided. The primary coil and the secondary coil are magnetically coupled, and the conductive member, the two coils, and the secondary capacitor are connected in parallel to each other and have two branch points. From the two branch points of this parallel connection, the reactance of the current path through the secondary coil is inductive, and the inductance of the secondary coil is larger than the inductance of the conductive member, and the inductance of the conductive member and the secondary side The capacitor constitutes a secondary side resonance circuit. And it is characterized in that it is magnetically coupled with a communication partner by a magnetic field generated by a current flowing through the conductive member.
　上記構成により、小型で通信特性の高い近傍界通信用のアンテナ装置を備える電子機器が構成される。 With the above configuration, an electronic device having a small-sized antenna device for near-field communication with high communication characteristics is configured.
　本発明によれば、回路構成の簡略化、占有面積の削減および通信特性の向上を図ったアンテナ装置およびそれを備える電子機器が得られる。 According to the present invention, it is possible to obtain an antenna device and an electronic device equipped with the antenna device with a simplified circuit configuration, a reduced occupied area, and improved communication characteristics.
図１は第１の実施形態に係るアンテナ装置１０１Ａの回路図である。FIG. 1 is a circuit diagram of an antenna device 101A according to the first embodiment. 図２は、第１の実施形態に係る別のアンテナ装置１０１Ｂの回路図である。FIG. 2 is a circuit diagram of another antenna device 101B according to the first embodiment. 図３は磁気結合素子３の外観斜視図である。FIG. 3 is an external perspective view of the magnetic coupling element 3. 図４は磁気結合素子３の内部の１次コイルＬ１および２次コイルＬ２の形成部の拡大図である。FIG. 4 is an enlarged view of a portion where the primary coil L1 and the secondary coil L2 are formed inside the magnetic coupling element 3. 図５は磁気結合素子３の断面図である。FIG. 5 is a cross-sectional view of the magnetic coupling element 3. 図６は第２の実施形態に係るアンテナ装置１０２Ａの回路図である。FIG. 6 is a circuit diagram of an antenna device 102A according to the second embodiment. 図７は第２の実施形態に係る別のアンテナ装置１０２Ｂの回路図である。FIG. 7 is a circuit diagram of another antenna device 102B according to the second embodiment. 図８は１次コイルＬ１に流れる電流ｉ１と導電性部材２０に流れる電流ｉAの周波数特性を示す図である。Figure 8 is a graph showing the frequency characteristic of the current i A flowing through the current i1 and the conductive member 20 flowing through the primary coil L1. 図９は第３の実施形態に係る電子機器に設けられているアンテナ装置の概略横断面図である。FIG. 9 is a schematic cross-sectional view of an antenna device provided in an electronic apparatus according to the third embodiment. 図１０は筐体の金属部２０Ｆ，２１Ｆの形状を示す斜視図である。FIG. 10 is a perspective view showing the shape of the metal parts 20F and 21F of the housing. 図１１は、図１０に示した筐体の金属部とは異なる形状の筐体金属部の例を示す斜視図である。FIG. 11 is a perspective view illustrating an example of a housing metal part having a shape different from that of the metal part of the housing illustrated in FIG. 10. 図１２は、図１０に示した筐体の金属部とは異なる形状の筐体金属部の例を示す斜視図である。12 is a perspective view showing an example of a housing metal part having a shape different from that of the metal part of the housing shown in FIG. 図１３は第４の実施形態に係る電子機器に設けられているアンテナ装置１０４Ａの平面図である。FIG. 13 is a plan view of an antenna device 104A provided in an electronic apparatus according to the fourth embodiment. 図１４は第４の実施形態に係る別の電子機器に設けられているアンテナ装置１０４Ｂの平面図である。FIG. 14 is a plan view of an antenna device 104B provided in another electronic apparatus according to the fourth embodiment. 図１５は第５の実施形態の磁気結合素子の回路図である。FIG. 15 is a circuit diagram of the magnetic coupling element according to the fifth embodiment. 図１６は第５の実施形態の別の磁気結合素子の回路図である。FIG. 16 is a circuit diagram of another magnetic coupling element according to the fifth embodiment. 図１７は、図１６に示す磁気結合素子の断面図である。17 is a cross-sectional view of the magnetic coupling element shown in FIG. 図１８は第６の実施形態のアンテナ装置１０６の回路図である。FIG. 18 is a circuit diagram of the antenna device 106 according to the sixth embodiment. 図１９は第７の実施形態のアンテナ装置１０７の回路図である。FIG. 19 is a circuit diagram of the antenna device 107 of the seventh embodiment. 図２０は第８の実施形態のアンテナ装置１０８の回路図である。FIG. 20 is a circuit diagram of the antenna device 108 of the eighth embodiment.
　以降、図を参照して幾つかの具体的な例を挙げて、本発明を実施するための複数の形態を示す。各図中には同一箇所に同一符号を付している。要点の説明または理解の容易性を考慮して、便宜上実施形態を分けて示すが、異なる実施形態で示した構成の部分的な置換または組み合わせは可能である。第２の実施形態以降では第１の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, several specific examples will be given with reference to the drawings to show a plurality of modes for carrying out the present invention. In each figure, the same reference numerals are assigned to the same portions. In consideration of ease of explanation or understanding of the main points, the embodiments are shown separately for convenience, but partial replacement or combination of configurations shown in different embodiments is possible. In the second and subsequent embodiments, description of matters common to the first embodiment is omitted, and only different points will be described. In particular, the same operation effect by the same configuration will not be sequentially described for each embodiment.
　以降に示す各実施形態において、「アンテナ装置」とは、磁束を放射するアンテナである。アンテナ装置は、通信相手側のアンテナと磁界結合を用いた近傍界通信のために用いられるアンテナであり、例えばＮＦＣ（Near field communication）等の通信に利用される。アンテナ装置は、使用する周波数帯は例えばHF帯で使用され、特に13.56MHzまたは13.56MHz近傍の周波数で用いられる。アンテナ装置の大きさは使用する周波数における波長λに比べて十分に小さいため、使用周波数帯においては電磁波の放射特性は悪い。後述のアンテナ装置が備えるコイルアンテナのコイル導体を延ばしたときのコイル導体の長さはλ／１０以下である。なお、ここでいう「波長」とは、アンテナが形成される基材の誘電性や透磁性による波長短縮効果を考慮した実効的な波長のことである。 In the following embodiments, the “antenna device” is an antenna that radiates magnetic flux. The antenna device is an antenna used for near-field communication using magnetic field coupling with an antenna on the communication partner side, and is used for communication such as NFC (Near field communication). The antenna device is used in the HF band, for example, and is used particularly at a frequency near 13.56 MHz or 13.56 MHz. Since the size of the antenna device is sufficiently smaller than the wavelength λ at the used frequency, the electromagnetic wave radiation characteristics are poor in the used frequency band. The length of the coil conductor when the coil conductor of the coil antenna provided in the antenna device described later is extended is λ / 10 or less. The “wavelength” here is an effective wavelength considering the wavelength shortening effect due to the dielectric property and permeability of the substrate on which the antenna is formed.
　コイルアンテナが有するコイル導体の両端には、使用周波数帯（HF帯、特に13.56MHz近傍）を操作する給電回路に接続される。よって、コイル導体には、コイル導体に沿って、つまり電流の流れる方向において、ほぼ一様な大きさの電流が流れ、コイル導体の長さが波長と同程度以上のときのように、コイル導体に沿った電流分布は生じ難い。 Both ends of the coil conductor of the coil antenna are connected to a power feeding circuit that operates the used frequency band (HF band, particularly around 13.56 MHz). Therefore, the coil conductor has a substantially uniform current flowing along the coil conductor, that is, in the direction in which the current flows, and the length of the coil conductor is equal to or greater than the wavelength. Current distribution along the line is unlikely to occur.
《第１の実施形態》
　図１は第１の実施形態に係るアンテナ装置１０１Ａの回路図である。このアンテナ装置１０１Ａは近傍界通信で用いられるアンテナ装置であって、例えばＮＦＣで通信を行うＲＦＩＤシステムにおけるリーダーライターに用いられる。または、リーダーライター機能を有する電子機器に用いられる。 << First Embodiment >>
FIG. 1 is a circuit diagram of an antenna device 101A according to the first embodiment. This antenna device 101A is an antenna device used in near-field communication, and is used, for example, as a reader / writer in an RFID system that performs NFC communication. Alternatively, it is used for an electronic device having a reader / writer function.
　アンテナ装置１０１Ａは、トランシーバＩＣ９に接続される１次側回路１と、２次側回路２と、を備える。トランシーバＩＣ９はリーダーライター制御機能を有する。１次側回路１は１次コイルＬ１を有する。２次側回路２は、導電性部材２０と２次コイルＬ２と２次側キャパシタＣ２とを有する。図１において、インダクタＬ２０は導電性部材２０によるインダクタンスを回路素子として表したものである。この導電性部材は例えば、実質的に１ターンのループアンテナとなる電子機器の筐体導体部である。トランシーバＩＣ９は本発明に係る「通信回路」の一例である。 The antenna device 101A includes a primary side circuit 1 and a secondary side circuit 2 connected to the transceiver IC9. The transceiver IC 9 has a reader / writer control function. The primary circuit 1 has a primary coil L1. The secondary side circuit 2 includes a conductive member 20, a secondary coil L2, and a secondary side capacitor C2. In FIG. 1, an inductor L20 represents the inductance by the conductive member 20 as a circuit element. This conductive member is, for example, a housing conductor part of an electronic device that is substantially a one-turn loop antenna. The transceiver IC 9 is an example of the “communication circuit” according to the present invention.
　１次コイルＬ１と２次コイルＬ２とは互いに磁界結合する。すなわち、１次コイルＬ１と２次コイルＬ２とで磁気結合素子（トランス）３が構成されている。導電性部材２０、２次コイルＬ２および２次側キャパシタＣ２は、互いに並列接続され、２つの分岐点を有する。 The primary coil L1 and the secondary coil L2 are magnetically coupled to each other. That is, the magnetic coupling element (transformer) 3 is comprised by the primary coil L1 and the secondary coil L2. The conductive member 20, the secondary coil L2, and the secondary capacitor C2 are connected in parallel to each other and have two branch points.
　導電性部材２０のインダクタンスと２次側キャパシタＣ２とは２次側共振回路ＲＣ２を構成している。 The inductance of the conductive member 20 and the secondary side capacitor C2 constitute a secondary side resonance circuit RC2.
　上記並列接続の２つの分岐点（接続点）ＣＮ１，ＣＮ２からみて、２次コイルＬ２の電流経路ＣＰのリアクタンスは誘導性である。図１では、電流経路ＣＰには、コイルＬ２のみが挿入されており誘導性である。また、コイルＬ２に対して直列にキャパシタが接続される場合には、分岐点ＣＮ１，ＣＮ２から２次コイルＬ２を視た回路の誘導性リアクタンスをωＬ、容量性リアクタンスを１／ωＣで表すと、ωＬ＞１／ωＣの関係にある誘導性となる。 The reactance of the current path CP of the secondary coil L2 is inductive when viewed from the two branch points (connection points) CN1 and CN2 of the parallel connection. In FIG. 1, only the coil L2 is inserted into the current path CP, which is inductive. In addition, when a capacitor is connected in series with the coil L2, the inductive reactance of the circuit when the secondary coil L2 is viewed from the branch points CN1 and CN2 is represented by ωL, and the capacitive reactance is represented by 1 / ωC. Inductivity is in a relationship of ωL> 1 / ωC.
　また、２次コイルＬ２のインダクタンスは導電性部材２０のインダクタンスよりも大きい。つまり、２次コイルＬ２のインダクタンスをＬ２で表し、導電性部材２０のアンテナループとしてのインダクタンスをＬAで表すと、Ｌ２＞ＬA、すなわちＬA／Ｌ２＜１の関係にある。 Further, the inductance of the secondary coil L2 is larger than the inductance of the conductive member 20. That represents the inductance of the secondary coil L2 by L2, to represent the inductance of the antenna loop of the conductive member 20 in L A, L2> is L A, that is, the relationship of L A / L2 <1.
　上述のとおり、２次コイルＬ２に対して、導電性部材２０によるインダクタＬ２０と２次側キャパシタＣ２とが並列接続されていて、導電性部材２０によるインダクタＬ２０と２次側キャパシタＣ２とで２次側共振回路ＲＣ２が構成されている。この２次側共振回路ＲＣ２の作用は次のとおりである。 As described above, the inductor L20 by the conductive member 20 and the secondary side capacitor C2 are connected in parallel to the secondary coil L2, and the secondary by the inductor L20 by the conductive member 20 and the secondary side capacitor C2. A side resonance circuit RC2 is configured. The operation of the secondary side resonance circuit RC2 is as follows.
　先ず、導電性部材２０によるインダクタＬ２０に比べて２次コイルＬ２のインダクタンスが大きいことにより、２次コイルＬ２よりインダクタＬ２０の方へ電流が流れやすい。そのため、２次コイルＬ２に流れる電流ｉ２に比べて２次側共振回路ＲＣ２に流れる電流ｉA が大きい。 First, since the inductance of the secondary coil L2 is larger than that of the inductor L20 made of the conductive member 20, a current easily flows from the secondary coil L2 to the inductor L20. Therefore, the current i A flowing through the secondary side resonance circuit RC2 is larger than the current i2 flowing through the secondary coil L2.
　また、２次側共振回路ＲＣ２に流れる電流ｉA は共振電流であるので、後に示すように、２次側共振回路ＲＣ２のＱ値に応じた大きな電流とすることができる。さらに、２次側共振回路ＲＣ２のＱ値を高くする（例えば、Ｑ値を５以上とする）ことで、２次側共振回路ＲＣ２内でのエネルギーの消費を抑えることができる。 Further, since the current i A flowing through the secondary side resonance circuit RC2 is a resonance current, it can be a large current according to the Q value of the secondary side resonance circuit RC2, as will be described later. Furthermore, by increasing the Q value of the secondary side resonance circuit RC2 (for example, setting the Q value to 5 or more), energy consumption in the secondary side resonance circuit RC2 can be suppressed.
　また、２次コイルＬ２の自己インダクタンスを導電性部材２０のインダクタンスＬAより十分大きな値とすることにより、２次側共振回路ＲＣ２のインピーダンスに対する２次コイルＬ２の影響を小さくすることができる。これにより、２次側共振回路ＲＣ２の駆動周波数付近でのインピーダンス特性（たとえば、共振周波数）を、主に導電性部材２０および２次側キャパシタＣ２の特性で定めることができる。 Further, it is possible by a sufficiently large value than the inductance L A of the conductive member 20 the self-inductance of the secondary coil L2, to reduce the influence of the secondary coil L2 with respect to the impedance of the secondary side resonant circuit RC2. Thereby, the impedance characteristic (for example, resonance frequency) near the drive frequency of the secondary side resonance circuit RC2 can be determined mainly by the characteristics of the conductive member 20 and the secondary side capacitor C2.
　ここで、
　導電性部材２０によるアンテナループのインダクタンス： LA
　アンテナループの抵抗値：RA
　アンテナループのQ 値：QA（＝ωLA / RA）
　２次側キャパシタの容量： C2
　２次コイルＬ２のインダクタンス： L2
　電流増幅率：G2
　２次側共振回路ＲＣ２の両端電圧：VA
　２次コイルＬ２に流れる電流：i2
　アンテナループに流れる電流：iA
　２次側キャパシタＣ２に流れる電流：iC
　アンテナループと２次側キャパシタＣ２による共振周波数：ωA
　でそれぞれ表すと、
　それらは次の関係で表される。 here,
Antenna loop inductance due to conductive member 20: L A
Antenna loop resistance: R A
Q value of antenna loop: Q A (= ωL A / R A )
Secondary capacitor capacity: C 2
Inductance of secondary coil L2: L 2
Current gain: G 2
Voltage at both ends of the secondary side resonance circuit RC2: V A
Current flowing through the secondary coil L2: i 2
Current flowing in the antenna loop: i A
Current flowing in secondary capacitor C2: i C
Resonant frequency by antenna loop and secondary capacitor C2: ω A
Respectively,
They are represented by the following relationship:
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　また、［数１］から電流増幅率|G2|は、 From [Equation 1], the current gain | G 2 |
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　通常、駆動周波数ωは、アンテナループと２次側キャパシタＣ２とによる共振周波数ωA に近く設定するので、ω≒ωA として分母の第一項を無視すると、電流増幅率は次式で表される。 Normally, the drive frequency ω is set close to the resonance frequency ω A of the antenna loop and the secondary capacitor C2, so if the first term of the denominator is ignored as ω≈ω A , the current amplification factor is expressed by the following equation. The
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　すなわち、導電性部材２０に流れる電流は、２次コイルＬ２に流れる電流の約QA 倍増幅される。 That is, the current flowing through the conductive member 20 is amplified by about Q A times the current flowing through the secondary coil L2.
　上記導電性部材２０に流れる電流ｉAにより発生する磁界によって通信相手と磁界結合によって通信がなされるので、ＮＦＣ通信に適したアンテナ装置として利用できる。 Since communication is performed with a communication partner by magnetic field coupling by the magnetic field generated by the current i A flowing through the conductive member 20, it can be used as an antenna device suitable for NFC communication.
　１次コイルＬ１と２次コイルＬ２との結合係数ｋは、１未満であり、より好適には、０．４以上０．９以下である。磁気結合素子３の１次コイルＬ１側の電流を効率よく２次コイルＬ２側に供給する（電流ｉ２をなるべく大きくする）ためには、上記結合係数ｋをできるだけ大きくすることが重要である。但し、後に示すように、１次側共振回路を共振させるためには、磁気結合素子３の漏れインダクタンスが必要である。 The coupling coefficient k between the primary coil L1 and the secondary coil L2 is less than 1, and more preferably 0.4 or more and 0.9 or less. In order to efficiently supply the current on the primary coil L1 side of the magnetic coupling element 3 to the secondary coil L2 side (to increase the current i2 as much as possible), it is important to increase the coupling coefficient k as much as possible. However, as will be described later, in order to resonate the primary side resonance circuit, the leakage inductance of the magnetic coupling element 3 is necessary.
　上記２次コイルＬ２の自己インダクタンスは例えば５μＨ、１次コイルＬ１の自己インダクタンスは例えば２μＨである。２次側共振回路ＲＣ２に流れる電流は、２次コイルＬ２の自己インダクタンスと導電性部材２０のインダクタンスＬAとの逆数比に従って分流される。導電性部材２０に大きな電流を流したいので、２次コイルＬ２の自己インダクタンスは導電性部材２０のインダクタンスＬA例えば０．０５μＨより十分大きな値（少なくとも５倍以上）とすることが好ましい。但し、２次コイルＬ２の自己インダクタンスを大きくすることと、磁気結合素子３を小型化することとはトレードオフの関係であるので、例えば、ＬAの１００倍程度である５μＨ程度にとどめることが好ましい。 The self-inductance of the secondary coil L2 is 5 μH, for example, and the self-inductance of the primary coil L1 is 2 μH, for example. Current flowing through the secondary side resonance circuit RC2 is diverted in accordance with the inverse ratio of the inductance L A of the self-inductance and the conductive member 20 of the secondary coil L2. We want a large current flows in the conductive members 20, the self-inductance of the secondary coil L2 is preferably an inductance L A example sufficiently larger than 0.05μH the conductive member 20 (at least 5 times or more). However, the increasing the self-inductance of the secondary coil L2, since the possible to reduce the size of the magnetic coupling element 3 is a relation of trade-off, for example, it is kept at about 5μH 100 times the L A preferable.
　また、トランシーバＩＣ９と２次側共振回路ＲＣ２とを整合させるためには、通常、２次コイルＬ２の自己インダクタンスに対して１次コイルＬ１の自己インダクタンスを小さくする。上述のとおり、２次コイルＬ２の自己インダクタンスは例えば５μＨ、１次コイルＬ１の自己インダクタンスは例えば２μＨである。そのことによって、必要な電流をトランシーバＩＣ９から引き出せるようにする。なお、トランシーバＩＣの仕様に応じてＬ１とＬ２の大小関係は変化する場合がある。 Further, in order to match the transceiver IC 9 and the secondary side resonance circuit RC2, normally, the self inductance of the primary coil L1 is made smaller than the self inductance of the secondary coil L2. As described above, the self-inductance of the secondary coil L2 is 5 μH, for example, and the self-inductance of the primary coil L1 is 2 μH, for example. This allows the necessary current to be drawn from the transceiver IC9. The magnitude relationship between L1 and L2 may change depending on the specifications of the transceiver IC.
　図２は、第１の実施形態に係る別のアンテナ装置１０１Ｂの回路図である。図１に示したアンテナ装置１０１Ａとは、２次側回路２の構成が異なる。１次側回路１はアンテナ装置１０１Ａの１次側回路１と同じであるが、図２では、トランシーバＩＣを高周波の電圧源９Ｅとして表している。 FIG. 2 is a circuit diagram of another antenna device 101B according to the first embodiment. The configuration of the secondary circuit 2 is different from the antenna device 101A shown in FIG. Although the primary side circuit 1 is the same as the primary side circuit 1 of the antenna device 101A, in FIG. 2, the transceiver IC is represented as a high frequency voltage source 9E.
　図２に示す例では、２次コイルＬ２に生じる寄生容量Ｃｓを図示している。また、この例では、２次コイルＬ２の電流経路ＣＰにキャパシタＣ２１を備えている。このように電流経路ＣＰに対し直列にキャパシタＣ２１が挿入されている場合、この電流経路ＣＰのリアクタンスを誘導性に設定する。 In the example shown in FIG. 2, the parasitic capacitance Cs generated in the secondary coil L2 is illustrated. In this example, the capacitor C21 is provided in the current path CP of the secondary coil L2. When the capacitor C21 is thus inserted in series with the current path CP, the reactance of the current path CP is set to be inductive.
　１次コイルＬ１と２次コイルＬ２とで磁気結合素子３が構成されている。また、寄生容量Ｃｓ、キャパシタＣ２１および２次側キャパシタＣ２によってπ型の容量結合回路４が構成される。 The magnetic coupling element 3 is comprised by the primary coil L1 and the secondary coil L2. Further, a π-type capacitive coupling circuit 4 is configured by the parasitic capacitance Cs, the capacitor C21, and the secondary side capacitor C2.
　導電性部材２０に、より大きな電流を流すためには、２次コイルＬ２の誘導電圧を大きくして、２次側共振回路ＲＣ２に、より高い電圧を印加することが重要である。そのために、１次コイルＬ１および２次コイルＬ２の相互インダクタンス、および特に２次コイルＬ２の自己インダクタンスを大きくする。 In order to flow a larger current through the conductive member 20, it is important to increase the induced voltage of the secondary coil L2 and apply a higher voltage to the secondary side resonance circuit RC2. For this purpose, the mutual inductance of the primary coil L1 and the secondary coil L2, and particularly the self-inductance of the secondary coil L2, is increased.
　ところが、２次コイルＬ２の自己インダクタンスを大きくすると、２次コイルＬ２の構造上、寄生容量Ｃｓが大きくなる場合がある。特に、インダクタンスを大きくするために多数のコイル導体を高密度に配置して磁気結合素子を小型化すると、導体が近接して寄生容量が増加し、寄生容量の影響が無視できなくなる。 However, if the self-inductance of the secondary coil L2 is increased, the parasitic capacitance Cs may increase due to the structure of the secondary coil L2. In particular, when a large number of coil conductors are arranged at a high density in order to increase the inductance and the magnetic coupling element is miniaturized, the conductors come close to each other and the parasitic capacitance increases, and the influence of the parasitic capacitance cannot be ignored.
　図２に示したように、２次コイルＬ２の電流経路に直列にキャパシタＣ２１を挿入すると、寄生容量Ｃｓの影響で、２次側共振回路ＲＣ２の共振周波数特性が急峻になったり、損失が増大したりする場合がある。これは、上記容量結合回路４が構成されるためである。 As shown in FIG. 2, when the capacitor C21 is inserted in series with the current path of the secondary coil L2, the resonance frequency characteristic of the secondary side resonance circuit RC2 becomes steep or the loss increases due to the influence of the parasitic capacitance Cs. There is a case to do. This is because the capacitive coupling circuit 4 is configured.
　直列キャパシタＣ２１のキャパシタンスを大きくして、２次コイルＬ２の電流経路ＣＰのリアクタンスを誘導性にすると、寄生容量の影響を軽減することができ、２次側共振回路ＲＣ２と磁気結合素子３（２次コイルＬ２）との結合を高めることができる。 If the reactance of the current path CP of the secondary coil L2 is made inductive by increasing the capacitance of the series capacitor C21, the influence of the parasitic capacitance can be reduced, and the secondary resonance circuit RC2 and the magnetic coupling element 3 (2 The coupling with the secondary coil L2) can be enhanced.
　このように、寄生容量の影響を実質的に無くすことで、２次側共振回路ＲＣ２に、より高い電圧を印加でき、導電性部材２０に、より大きな電流を流すことができる。 As described above, by substantially eliminating the influence of the parasitic capacitance, a higher voltage can be applied to the secondary side resonance circuit RC2, and a larger current can flow through the conductive member 20.
　次に、磁気結合素子３の構成について示す。 Next, the configuration of the magnetic coupling element 3 will be described.
　図３は磁気結合素子３の外観斜視図である。図４は磁気結合素子３の内部の１次コイルＬ１および２次コイルＬ２の形成部の拡大図であり、特に積層方向に伸長させて表している。図５は磁気結合素子３の断面図である。 FIG. 3 is an external perspective view of the magnetic coupling element 3. FIG. 4 is an enlarged view of a portion where the primary coil L1 and the secondary coil L2 in the magnetic coupling element 3 are formed, and is particularly shown extended in the stacking direction. FIG. 5 is a cross-sectional view of the magnetic coupling element 3.
　磁気結合素子３は直方体形状の積層型チップ部品であり、その底面に１次コイルＬ１の両端が導通する端子と、２次コイルＬ２の両端が導通する端子と、が形成されている。磁気結合素子３はこれらの端子を実装端子として、回路基板に表面実装される。 The magnetic coupling element 3 is a rectangular parallelepiped laminated chip component, and a terminal on which both ends of the primary coil L1 are conductive and a terminal on which both ends of the secondary coil L2 are conductive are formed on the bottom surface. The magnetic coupling element 3 is surface-mounted on a circuit board using these terminals as mounting terminals.
　磁気結合素子３は、１次コイルＬ１および２次コイルＬ２が積層型チップ部品として一体的に形成された素子である。この磁気結合素子３はインダクタンスを高くするために磁性層を有する。例えば、１次コイルＬ１、２次コイルＬ２の形成層および１次コイルＬ１と２次コイルＬ２との間の層は磁性フェライトの層であり、その他の層は非磁性フェライトの層である。なお、非磁性層を形成しない構成でもよい。 The magnetic coupling element 3 is an element in which a primary coil L1 and a secondary coil L2 are integrally formed as a multilayer chip component. The magnetic coupling element 3 has a magnetic layer in order to increase the inductance. For example, the formation layer of the primary coil L1, the secondary coil L2, and the layer between the primary coil L1 and the secondary coil L2 are magnetic ferrite layers, and the other layers are nonmagnetic ferrite layers. In addition, the structure which does not form a nonmagnetic layer may be sufficient.
　図４において、ループ状またはその部分形状のパターンはコイル導体パターンであり、縦方向に延伸するパターンは層間接続導体である。この図４に表れているように、１次コイルＬ１は複数の１次コイル導体パターンＬ１１，Ｌ１２，Ｌ１３，Ｌ１４，Ｌ１５，Ｌ１６と、これらを層間接続する層間接続導体と、を備える。同様に、２次コイルＬ２は複数の２次コイル導体パターンＬ２１，Ｌ２２，Ｌ２３，Ｌ２４と、これらを層間接続する層間接続導体と、を備える。 In FIG. 4, the loop pattern or a partial pattern thereof is a coil conductor pattern, and the pattern extending in the vertical direction is an interlayer connection conductor. As shown in FIG. 4, the primary coil L1 includes a plurality of primary coil conductor patterns L11, L12, L13, L14, L15, and L16 and interlayer connection conductors that connect these layers. Similarly, the secondary coil L2 includes a plurality of secondary coil conductor patterns L21, L22, L23, and L24, and interlayer connection conductors that connect these layers.
　１次コイルＬ１は約５ターンのヘリカル状コイルであり、２次コイルＬ２は約４ターンのヘリカル状コイルである。 The primary coil L1 is a helical coil having about 5 turns, and the secondary coil L2 is a helical coil having about 4 turns.
　図４、図５に示すように、１次コイルＬ１と２次コイルＬ２とは近接して積層されていて、１次コイルＬ１と２次コイルＬ２のコイル開口は重なり、１次コイルＬ１の巻回軸と２次コイルＬ２の巻回軸は同軸関係にある。 As shown in FIGS. 4 and 5, the primary coil L1 and the secondary coil L2 are laminated close to each other, and the coil openings of the primary coil L1 and the secondary coil L2 are overlapped, and the primary coil L1 is wound. The rotation axis and the winding axis of the secondary coil L2 are in a coaxial relationship.
《第２の実施形態》
　第２の実施形態では１次側共振回路を備えたアンテナ装置の例を示す。図６は第２の実施形態に係るアンテナ装置１０２Ａの回路図である。図７は第２の実施形態に係る別のアンテナ装置１０２Ｂの回路図である。いずれも、図１に示した例とは、１次側回路１の構成が異なる。 << Second Embodiment >>
In the second embodiment, an example of an antenna device including a primary side resonance circuit is shown. FIG. 6 is a circuit diagram of an antenna device 102A according to the second embodiment. FIG. 7 is a circuit diagram of another antenna device 102B according to the second embodiment. In either case, the configuration of the primary circuit 1 is different from the example shown in FIG.
　図６に示すアンテナ装置１０２Ａは、トランシーバＩＣ９に接続される１次側回路１と、２次側回路２と、を備える。トランシーバＩＣ９は送信信号出力ポートＴｘと受信信号入力ポートＲｘとを有する。１次側回路１は１次コイルＬ１、１次側キャパシタＣ１１，Ｃ１２およびインダクタＬｆ１，Ｌｆ２を有する。１次コイルＬ１、インダクタＬｆ１，Ｌｆ２および１次側キャパシタＣ１１，Ｃ１２によって１次側共振回路ＲＣ１が構成されている。１次側キャパシタＣ１１，Ｃ１２を挿入することにより、トランシーバＩＣ９から視たインピーダンスを所定のインピーダンス（例えば２０Ω以上～８０Ω以下のインピーダンス）に設定でき、そのことでトランシーバＩＣ９とアンテナとの間のインピーダンス整合が図れる。 The antenna device 102A shown in FIG. 6 includes a primary side circuit 1 and a secondary side circuit 2 connected to the transceiver IC9. The transceiver IC 9 has a transmission signal output port Tx and a reception signal input port Rx. The primary side circuit 1 has a primary coil L1, primary side capacitors C11 and C12, and inductors Lf1 and Lf2. A primary side resonance circuit RC1 is configured by the primary coil L1, the inductors Lf1 and Lf2, and the primary side capacitors C11 and C12. By inserting the primary side capacitors C11 and C12, the impedance viewed from the transceiver IC9 can be set to a predetermined impedance (for example, an impedance of 20Ω to 80Ω or less), and thereby impedance matching between the transceiver IC9 and the antenna Can be planned.
　図７に示すアンテナ装置１０２Ｂでは、１次側回路１は１次コイルＬ１および１次側キャパシタＣ１０を有する。１次コイルＬ１および１次側キャパシタＣ１０によって１次側共振回路ＲＣ１が構成されている。その他の構成は、図６または図１に示したアンテナ装置と同じである。トランシーバＩＣ９の送信信号出力ポートＴｘを平衡回路としているが、不平衡回路の場合には、１次コイルＬ１の一端をグランド導体に接続してもよい。 In the antenna device 102B shown in FIG. 7, the primary side circuit 1 has a primary coil L1 and a primary side capacitor C10. A primary side resonance circuit RC1 is configured by the primary coil L1 and the primary side capacitor C10. Other configurations are the same as those of the antenna device shown in FIG. 6 or FIG. Although the transmission signal output port Tx of the transceiver IC 9 is a balanced circuit, one end of the primary coil L1 may be connected to the ground conductor in the case of an unbalanced circuit.
　１次側共振回路ＲＣ１と２次側共振回路ＲＣ２とは結合して一つの結合共振回路が構成されている。近傍界通信の通信周波数は、この結合共振回路により生じる２つの共振周波数の間にある。 The primary side resonance circuit RC1 and the secondary side resonance circuit RC2 are coupled to form one coupled resonance circuit. The communication frequency of near-field communication is between two resonance frequencies generated by this coupled resonance circuit.
　上記インダクタＬｆ１，Ｌｆ２は、トランシーバＩＣ９の２つのＴｘポートに重畳されるノーマルモード電圧、および、コモンモード電圧の高調波成分を含む高周波ノイズを遮断する。これらインダクタは基本的に不要であるが、高周波ノイズをさらに低減したい場合など、必要に応じて追加すればよい。通常、１次コイルＬ１のインダクタンスよりも小さな値に設定する。 The inductors Lf1 and Lf2 block high frequency noise including harmonic components of the normal mode voltage and the common mode voltage superimposed on the two Tx ports of the transceiver IC9. These inductors are basically unnecessary, but may be added as necessary when further reduction of high frequency noise is desired. Usually, it is set to a value smaller than the inductance of the primary coil L1.
　図８は１次コイルＬ１に流れる電流ｉ１と導電性部材２０に流れる電流ｉＡの周波数特性を示す図である。いずれも周波数ｆ１，ｆ２にピークを有する双峰性を示す。この２つのピーク周波数ｆ１，ｆ２は、１次側共振回路ＲＣ１と２次側共振回路ＲＣ２とが結合して生じる結合共振回路の共振周波数である。１次側共振回路ＲＣ１と２次側共振回路ＲＣ２の共振周波数は通信周波数ｆｏｐにほぼ等しいが、両者が結合することによって、その結合係数に応じて２つのピーク周波数が分離する。結合係数が１であると双峰性を示さないので、既に述べたように、結合係数ｋは例えば０．４以上０．９以下に定める。 FIG. 8 is a diagram showing frequency characteristics of the current i1 flowing through the primary coil L1 and the current iA flowing through the conductive member 20. Both show bimodality having peaks at frequencies f1 and f2. The two peak frequencies f1 and f2 are resonance frequencies of a coupled resonance circuit generated by coupling the primary side resonance circuit RC1 and the secondary side resonance circuit RC2. The resonance frequencies of the primary side resonance circuit RC1 and the secondary side resonance circuit RC2 are substantially equal to the communication frequency hop, but when they are coupled, the two peak frequencies are separated according to the coupling coefficient. Since the bimodality is not shown when the coupling coefficient is 1, the coupling coefficient k is set to 0.4 or more and 0.9 or less, for example, as described above.
　このように、１次側共振回路ＲＣ１と２次側共振回路ＲＣ２との結合により構成される結合共振回路は帯域通過特性を示す。トランシーバＩＣ９で発生する高周波ノイズ成分は、結合共振回路を通過する際に減衰し、アンテナとして機能する導電性部材から放射されにくくなる。すなわち、結合共振回路がフィルタ特性を示すので、トランシーバＩＣ９と磁気結合素子３との間に設けるＥＭＩ対策用のフィルタ回路を簡略化でき、整合回路の部品点数を減らすことにより、機器に組み込み易くなる。 Thus, the coupled resonant circuit configured by coupling the primary side resonant circuit RC1 and the secondary side resonant circuit RC2 exhibits bandpass characteristics. The high frequency noise component generated in the transceiver IC 9 is attenuated when passing through the coupled resonance circuit, and is not easily radiated from the conductive member functioning as an antenna. That is, since the coupled resonant circuit exhibits filter characteristics, the filter circuit for EMI countermeasures provided between the transceiver IC 9 and the magnetic coupling element 3 can be simplified, and the number of parts of the matching circuit can be reduced, so that it can be easily incorporated into equipment. .
《第３の実施形態》
　第３の実施形態では、電子機器の幾つかの構成例を示す。 << Third Embodiment >>
In the third embodiment, several configuration examples of the electronic device are shown.
　図９は電子機器に設けられているアンテナ装置の概略横断面図である。筐体は金属部２０Ｆ，２１Ｆを備える。この金属部２０Ｆは本発明に係る「導電性部材」に対応する。 FIG. 9 is a schematic cross-sectional view of an antenna device provided in an electronic device. The housing includes metal parts 20F and 21F. The metal portion 20F corresponds to a “conductive member” according to the present invention.
　図１０は上記筐体の金属部２０Ｆ，２１Ｆの形状を示す斜視図である。金属部２０Ｆは例えばスマートフォンの一つの端部に位置する。 FIG. 10 is a perspective view showing the shapes of the metal portions 20F and 21F of the casing. The metal part 20F is located at one end of a smartphone, for example.
　本実施形態では、回路基板５にトランシーバＩＣ９、１次側キャパシタＣ１１，Ｃ１２、磁気結合素子３および２次側キャパシタＣ２が形成されていて、この回路基板５が筐体内に収容されている。２次側キャパシタＣ２の一端は回路グランドに接続されていて、他端はピン端子（プローブピン）等を介して筐体の金属部２０Ｆの一部に接続されている。また、金属部２０Ｆの他部は別のピン端子（プローブピン）等を介して回路基板５のグランド導体に接続されている。この構造により、筐体の金属部２０Ｆの一部と回路基板５のグランド導体の一部とで、図中に破線のループで示すような電流経路が構成され、これがループアンテナとして作用する。 In the present embodiment, the transceiver IC 9, the primary side capacitors C11 and C12, the magnetic coupling element 3, and the secondary side capacitor C2 are formed on the circuit board 5, and the circuit board 5 is accommodated in the housing. One end of the secondary capacitor C2 is connected to the circuit ground, and the other end is connected to a part of the metal portion 20F of the housing via a pin terminal (probe pin) or the like. The other part of the metal part 20F is connected to the ground conductor of the circuit board 5 via another pin terminal (probe pin) or the like. With this structure, a part of the metal part 20F of the casing and a part of the ground conductor of the circuit board 5 form a current path as shown by a broken loop in the figure, and this acts as a loop antenna.
　図１１、図１２は、図１０に示した筐体の金属部とは異なる形状の筐体金属部の例を示す斜視図である。図１１に示す例では、筐体金属部２０Ｆは平板ではなく、図１１におけるＸ軸方向の両端およびＹ軸方向の一端にも形成され、接続されている。図１２に示す例では、筐体金属部２０Ｆは、Ｙ方向から視て、コの字状（Ｕ字状）の導体である。 FIG. 11 and FIG. 12 are perspective views showing examples of a case metal part having a shape different from the metal part of the case shown in FIG. In the example shown in FIG. 11, the housing metal part 20 </ b> F is not formed as a flat plate but is formed and connected to both ends in the X-axis direction and one end in the Y-axis direction in FIG. 11. In the example illustrated in FIG. 12, the housing metal part 20 </ b> F is a U-shaped (U-shaped) conductor as viewed from the Y direction.
　このような形状であっても、筐体金属部２０Ｆをループアンテナの一部として利用できる。 Even in such a shape, the metal case 20F can be used as a part of the loop antenna.
《第４の実施形態》
　第４の実施形態では、導電性部材の構成がこれまでに示した例とは異なる電子機器の幾つかの例を示す。 << Fourth Embodiment >>
In the fourth embodiment, some examples of electronic devices in which the configuration of the conductive member is different from the examples shown so far will be described.
　図１３は電子機器に設けられているアンテナ装置１０４Ａの平面図である。このアンテナ装置１０４Ａはループ導体２０Ｌを備える。このループ導体２０Ｌは本発明に係る「導電性部材」に対応する。 FIG. 13 is a plan view of the antenna device 104A provided in the electronic apparatus. This antenna device 104A includes a loop conductor 20L. The loop conductor 20L corresponds to a “conductive member” according to the present invention.
　図１４は電子機器に設けられているアンテナ装置１０４Ｂの平面図である。このアンテナ装置１０４Ｂはループ導体２０Ｌ１，２０Ｌ２を備える。このループ導体２０Ｌ１，２０Ｌ２は本発明に係る「導電性部材」に対応する。 FIG. 14 is a plan view of the antenna device 104B provided in the electronic apparatus. This antenna device 104B includes loop conductors 20L1 and 20L2. The loop conductors 20L1 and 20L2 correspond to “conductive members” according to the present invention.
　上記ループ導体２０Ｌ，２０Ｌ１，２０Ｌ２は例えば回路基板や筐体に形成された導体パターンである。このように、パターン形成された導体を「導電性部材」に用いてもよい。 The loop conductors 20L, 20L1, and 20L2 are conductor patterns formed on, for example, a circuit board or a casing. As described above, the conductor formed with a pattern may be used as the “conductive member”.
　図１４に示したように２つのループ導体２０Ｌ１，２０Ｌ２を設けることで、これらループ導体２０Ｌ１，２０Ｌ２それぞれをループアンテナとして作用させることができる。このことで、通信範囲の自由度が向上する。 As shown in FIG. 14, by providing two loop conductors 20L1 and 20L2, each of these loop conductors 20L1 and 20L2 can act as a loop antenna. This improves the degree of freedom of the communication range.
　図１４に示した例では、２つのループ導体２０Ｌ１，２０Ｌ２を同一面に配置したが、２つのループ導体を基板の表裏に形成してもよい。また、２つのループ導体を３次元的に配置してもよい。例えば一方のループ導体を筐体や基板の表面または裏面に形成し、他方のループ導体を筐体や基板の側面に形成してもよい。 In the example shown in FIG. 14, the two loop conductors 20L1 and 20L2 are arranged on the same surface, but the two loop conductors may be formed on the front and back of the substrate. Two loop conductors may be arranged three-dimensionally. For example, one loop conductor may be formed on the front surface or the back surface of the housing or the substrate, and the other loop conductor may be formed on the side surface of the housing or the substrate.
　また、図１４に示した例では、２つのループ導体２０Ｌ１，２０Ｌ２を並列接続したが、これらを直列接続してもよい。また、３つ以上のループ導体を設けてもよい。 In the example shown in FIG. 14, the two loop conductors 20L1 and 20L2 are connected in parallel, but they may be connected in series. Three or more loop conductors may be provided.
《第５の実施形態》
　第５の実施形態では、磁気結合素子の構成例を示す。 << Fifth Embodiment >>
In the fifth embodiment, a configuration example of a magnetic coupling element is shown.
　図１５は第５の実施形態の磁気結合素子の回路図である。この例では１次コイルＬ１の中点をグランドに接続している。この構成によれば、トランシーバＩＣのスイッチング動作に伴って生じる高周波ノイズ（特にコモンモードノイズ成分）が低減される。なお、トランシーバＩＣの出力回路は平衡回路であることを想定している。 FIG. 15 is a circuit diagram of the magnetic coupling element of the fifth embodiment. In this example, the midpoint of the primary coil L1 is connected to the ground. According to this configuration, high-frequency noise (particularly common mode noise component) generated with the switching operation of the transceiver IC is reduced. Note that the output circuit of the transceiver IC is assumed to be a balanced circuit.
　図１６は第５の実施形態の別の磁気結合素子の回路図である。また、図１７はこの磁気結合素子の断面図である。１次コイルＬ１および２次コイルＬ２は、図３、図４、図５に示した磁気結合素子と同様に、磁性体フェライトの積層体に形成されたヘリカル状の導体パターンである。１次コイルＬ１の形成層と２次コイルＬ２の形成層との間に、それらの導体パターン間を遮蔽するシールド導体ＳＣの層が設けられている。上記積層体の下面（実装面）には１次コイルＬ１および２次コイルＬ２の端子（図１７中の端子Ｔ１，Ｔ２等）以外にグランド端子ＴＧが形成されていて、シールド導体ＳＣはグランド端子ＴＧに接続されている。 FIG. 16 is a circuit diagram of another magnetic coupling element according to the fifth embodiment. FIG. 17 is a cross-sectional view of this magnetic coupling element. The primary coil L1 and the secondary coil L2 are helical conductor patterns formed in a laminated body of magnetic ferrite, like the magnetic coupling elements shown in FIGS. Between the formation layer of the primary coil L1 and the formation layer of the secondary coil L2, the layer of the shield conductor SC which shields between those conductor patterns is provided. In addition to the terminals of the primary coil L1 and the secondary coil L2 (terminals T1, T2, etc. in FIG. 17), a ground terminal TG is formed on the lower surface (mounting surface) of the laminate, and the shield conductor SC is a ground terminal. Connected to TG.
　図１６、図１７に示した磁気結合素子を用いる場合も、トランシーバＩＣのスイッチング動作に伴って生じる高周波ノイズ（特にコモンモードノイズ成分）が低減される。 Also in the case of using the magnetic coupling element shown in FIGS. 16 and 17, high-frequency noise (particularly, common mode noise component) generated with the switching operation of the transceiver IC is reduced.
《第６の実施形態》
　第６の実施形態では、トランシーバＩＣに対する受信信号の入力構造がこれまでに示した例とは異なるアンテナ装置について示す。 << Sixth Embodiment >>
In the sixth embodiment, an antenna device in which the input structure of the received signal to the transceiver IC is different from the examples shown so far will be described.
　図１８は第６の実施形態のアンテナ装置１０６の回路図である。このアンテナ装置１０６に接続されるトランシーバＩＣ９は受信信号を差動入力する２つのＲｘ端子を有する。この２つのＲｘ端子には、１次コイルＬ１の両端が接続される。 FIG. 18 is a circuit diagram of the antenna device 106 of the sixth embodiment. The transceiver IC 9 connected to the antenna device 106 has two Rx terminals for differentially receiving received signals. Both ends of the primary coil L1 are connected to the two Rx terminals.
　本実施形態によれば、受信信号が１次コイルＬ１からトランシーバＩＣ９に差動で入力されるので、コモンモードノイズの影響を受けにくくなり、受信信号のＳＮＲ（signal-to-noise ratio）を高められる。 According to the present embodiment, since the received signal is differentially input from the primary coil L1 to the transceiver IC9, it is less susceptible to common mode noise and increases the SNR (signal-to-noise ratio) of the received signal. It is done.
《第７の実施形態》
　第７の実施形態では、２次側共振回路ＲＣ２の構成がこれまでの例とは異なるアンテナ装置について示す。 << Seventh Embodiment >>
In the seventh embodiment, an antenna device in which the configuration of the secondary side resonance circuit RC2 is different from the examples so far will be described.
　図１９は第７の実施形態のアンテナ装置１０７の回路図である。このアンテナ装置１０７に接続されるトランシーバＩＣ９は、２次側共振回路ＲＣ２の共振周波数を調整するための制御信号を出力する端子を有する。２次側共振回路ＲＣ２は、インダクタＬ２０、２次側キャパシタＣ２および可変容量素子Ｃ２０で構成されている。 FIG. 19 is a circuit diagram of the antenna device 107 of the seventh embodiment. The transceiver IC 9 connected to the antenna device 107 has a terminal for outputting a control signal for adjusting the resonance frequency of the secondary side resonance circuit RC2. The secondary side resonance circuit RC2 includes an inductor L20, a secondary side capacitor C2, and a variable capacitance element C20.
　可変容量素子Ｃ２０は、トランシーバＩＣ９から与えられる制御信号に応じてキャパシタンスが定まる。この可変容量素子Ｃ２０は、具体的には、複数ビットの制御信号をアナログ電圧信号に変換する抵抗回路によるＤＡコンバータ回路と、このアナログ電圧が印加される強誘電体キャパシタとで構成される。 The capacitance of the variable capacitance element C20 is determined according to the control signal given from the transceiver IC9. Specifically, the variable capacitance element C20 includes a DA converter circuit including a resistance circuit that converts a control signal of a plurality of bits into an analog voltage signal, and a ferroelectric capacitor to which the analog voltage is applied.
　本実施形態によれば、２次側キャパシタＣ２のキャパシタンスのばらつきや、アンテナ装置への金属の近接による共振周波数特性の変化があっても、２次側共振回路ＲＣ２の共振周波数を能動的に最適化される。そのため通信距離の低下が抑制できる。 According to the present embodiment, the resonance frequency of the secondary side resonance circuit RC2 is actively optimized even if there is a variation in the capacitance of the secondary side capacitor C2 or a change in the resonance frequency characteristics due to the proximity of the metal to the antenna device. It becomes. Therefore, a decrease in communication distance can be suppressed.
《第８の実施形態》
　第８の実施形態では、磁気結合素子３の構成が異なるアンテナ装置の例を示す。 << Eighth Embodiment >>
In the eighth embodiment, an example of an antenna device having a different configuration of the magnetic coupling element 3 is shown.
　図２０は第８の実施形態のアンテナ装置１０８の回路図である。このアンテナ装置１０８に接続されるトランシーバＩＣ９はシングルエンドのトランシーバＩＣである。磁気結合素子３はオートトランス型の素子であり、１次コイルＬ１と２次コイルＬ２１，Ｌ２２を備える。但し、１次コイルＬ１と２次コイルＬ２１とは同じコイルである。 FIG. 20 is a circuit diagram of the antenna device 108 of the eighth embodiment. The transceiver IC 9 connected to the antenna device 108 is a single-ended transceiver IC. The magnetic coupling element 3 is an autotransformer type element and includes a primary coil L1 and secondary coils L21 and L22. However, the primary coil L1 and the secondary coil L21 are the same coil.
　１次側回路１は１次コイルＬ１および１次側キャパシタＣ１０を有する。１次コイルＬ１および１次側キャパシタＣ１０によって１次側共振回路が構成されている。インダクタＬｆはトランシーバＩＣ９のＴｘポートに重畳される、高調波成分を含む高周波ノイズを遮断する。２次側回路２は、導電性部材２０と２次コイル（Ｌ２１，Ｌ２２）と２次側キャパシタＣ２とを有する。 The primary side circuit 1 has a primary coil L1 and a primary side capacitor C10. A primary side resonance circuit is configured by the primary coil L1 and the primary side capacitor C10. The inductor Lf blocks high frequency noise including harmonic components superimposed on the Tx port of the transceiver IC9. The secondary circuit 2 includes a conductive member 20, secondary coils (L21, L22), and a secondary capacitor C2.
　本実施形態のように、磁気結合素子３はオートトランス型の素子であってもよい。また、これまでに示した絶縁型のトランス構造であってもよい。 As in the present embodiment, the magnetic coupling element 3 may be an autotransformer element. Moreover, the insulation type transformer structure shown so far may be used.
《他の実施形態》
　以上の各実施形態では、通信用のアンテナ装置を主として述べたが、例えばＮＦＣよりも低周波数帯を利用する無線電力伝送システムに用いられる回路を備えた電子機器に本発明のアンテナ装置が混載されてもよい。その場合、アンテナ装置には上述のフィルタ機能を有することにより、無線電力伝送システムの高周波磁界（例えば、6.78MHz）をアンテナ装置で受電した場合であっても、ＮＦＣ用回路（トランシーバＩＣ９等）の破壊を防止できる。 << Other embodiments >>
In each of the embodiments described above, the communication antenna device has been mainly described. However, for example, the antenna device of the present invention is mixedly mounted on an electronic device including a circuit used in a wireless power transmission system that uses a lower frequency band than NFC. May be. In that case, since the antenna device has the above-described filter function, the NFC circuit (transceiver IC 9 or the like) can be used even when the antenna device receives a high-frequency magnetic field (eg, 6.78 MHz) of the wireless power transmission system. Destruction can be prevented.
　図３～図５、図１７では、コイルパターンが積層体内に形成されたトランス構造の磁気結合素子を示したが、本発明の磁気結合素子はこれに限らず、巻線型のトランスであってもよい。 3 to 5 and 17, the magnetic coupling element having the transformer structure in which the coil pattern is formed in the laminated body is shown. However, the magnetic coupling element of the present invention is not limited to this, and a winding type transformer may be used. Good.
　また、磁気結合素子を構成する積層体の全層が磁性層であってもよいし全層が非磁性層であってもよい。 Further, all the layers of the laminate constituting the magnetic coupling element may be magnetic layers, or all the layers may be nonmagnetic layers.
　図６、図７等に示した例では、磁気結合素子３の２次側からトランシーバＩＣ９へ受信信号を入力するように構成したが、磁気結合素子３の１次側から受信信号を取り出してもよい。また、Ｒｘポートとの間に必要に応じてインピーダンス整合回路（抵抗、キャパシタなど）を設けてもよい。 In the example shown in FIGS. 6 and 7, the reception signal is input to the transceiver IC 9 from the secondary side of the magnetic coupling element 3. However, even if the reception signal is extracted from the primary side of the magnetic coupling element 3. Good. In addition, an impedance matching circuit (such as a resistor or a capacitor) may be provided between the Rx port as necessary.
　上述の実施形態において、筐体金属部２０Ｆは、筐体を構成する金属部分であれば、どのような形状であってもよく、図１０～図１２に示すような形状（コの字形状等）に限られない。また、単一の部材である必要もなく、複数の部材により構成された筐体の金属部分であってもよい。 In the above-described embodiment, the casing metal portion 20F may have any shape as long as it is a metal portion constituting the casing, such as the shape shown in FIGS. Is not limited to). Moreover, it is not necessary to be a single member, and it may be a metal part of a housing constituted by a plurality of members.
　なお、上述の実施形態では、主にＮＦＣ等の磁界結合を利用した通信システムにおけるアンテナ装置および電子機器について説明したが、上述の実施形態におけるアンテナ装置および電子機器は、磁界結合を利用した非接触電力伝送システム（電磁誘導方式、磁界共鳴方式）にも同様に適用できる。例えば、上述の実施形態におけるアンテナ装置は、ＨＦ帯、特に6.78MHzまたは6.78MHz近傍の周波数で使用される磁界共鳴方式の非接触電力伝送システムの受電装置の受電アンテナ装置としてや、送電装置の送電アンテナ装置として適用できる。この場合、アンテナ装置のコイルアンテナが有するコイル導体の両端は、使用周波数帯（HF帯、特に6.78MHz近傍）を操作する受電回路や送電回路に接続される。その場合でも、アンテナ装置は受電アンテナ装置や送電アンテナ装置として機能する。受電回路には、例えば、受電コイルアンテナからの電力を負荷（二次電池等）に供給するために、整合回路、平滑回路、ＤＣ／ＤＣコンバータ等が含まれ、これらの回路が受電コイルアンテナと負荷との間に縦続接続される。また、送電回路には商用電源から送電コイルアンテナに電力を供給するために、整流回路、平滑回路、ＤＣ／ＡＣインバータとして機能するスイッチ回路等が含まれ、これらの回路が商用電源と送電コイルアンテナとの間に縦続接続される。 In the above-described embodiment, the antenna device and the electronic device in the communication system mainly using magnetic field coupling such as NFC have been described. However, the antenna device and the electronic device in the above-described embodiment are contactless using magnetic field coupling. The present invention can be similarly applied to a power transmission system (electromagnetic induction method, magnetic field resonance method). For example, the antenna device in the above-described embodiment is used as a power receiving antenna device of a power receiving device of a magnetic resonance type non-contact power transmission system used in the HF band, particularly in the vicinity of 6.78 MHz or 6.78 MHz. It can be applied as an antenna device. In this case, both ends of the coil conductor included in the coil antenna of the antenna device are connected to a power reception circuit or a power transmission circuit that operates a used frequency band (HF band, particularly around 6.78 MHz). Even in that case, the antenna device functions as a power receiving antenna device or a power transmitting antenna device. The power receiving circuit includes, for example, a matching circuit, a smoothing circuit, a DC / DC converter, and the like to supply power from the power receiving coil antenna to a load (secondary battery, etc.). These circuits are connected to the power receiving coil antenna. Cascaded between load. In addition, the power transmission circuit includes a rectifier circuit, a smoothing circuit, a switch circuit that functions as a DC / AC inverter, and the like for supplying power from the commercial power source to the power transmission coil antenna. Are connected in cascade.
　最後に、上述の実施形態の説明は、すべての点で例示であって、制限的なものではない。当業者にとって変形および変更が適宜可能である。本発明の範囲は、上述の実施形態ではなく、特許請求の範囲によって示される。さらに、本発明の範囲には、特許請求の範囲内と均等の範囲内での実施形態からの変更が含まれる。 Finally, the description of the above embodiment is illustrative in all respects and not restrictive. Modifications and changes can be made as appropriate by those skilled in the art. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope equivalent to the claims.
Ｃ１０，Ｃ１１，Ｃ１２…１次側キャパシタ
Ｃ２…２次側キャパシタ
Ｃ２０…可変容量素子
Ｃ２１…キャパシタ
ＣＮ１，ＣＮ２…分岐点
ＣＰ…電流経路
Ｃｓ…寄生容量
Ｌ１…１次コイル
Ｌ１１，Ｌ１２，Ｌ１３，Ｌ１４，Ｌ１５，Ｌ１６…１次コイル導体パターン
Ｌ２…２次コイル
Ｌ２０…導電性部材２０によるインダクタ
Ｌ２１，Ｌ２２，Ｌ２３，Ｌ２４…２次コイル導体パターン
Ｌｆ，Ｌｆ１，Ｌｆ２…インダクタ
ＲＣ１…１次側共振回路
ＲＣ２…２次側共振回路
Ｒｘ…受信信号入力ポート
ＳＣ…シールド導体
Ｔ１，Ｔ２…端子
ＴＧ…グランド端子
Ｔｘ…送信信号出力ポート
１…１次側回路
２…２次側回路
３…磁気結合素子
４…容量結合回路
５…回路基板
９…トランシーバＩＣ
２０…導電性部材
２０Ｆ，２１Ｆ…金属部
２０Ｌ，２０Ｌ１，２０Ｌ２…ループ導体
１０１Ａ，１０１Ｂ，１０２Ａ，１０２Ｂ，１０４Ａ，１０４Ｂ，１０６，１０７，１０８…アンテナ装置 C10, C11, C12 ... primary side capacitor C2 ... secondary side capacitor C20 ... variable capacitance element C21 ... capacitor CN1, CN2 ... branch point CP ... current path Cs ... parasitic capacitance L1 ... primary coils L11, L12, L13, L14 , L15, L16 ... primary coil conductor pattern L2 ... secondary coil L20 ... inductors L21, L22, L23, L24 ... secondary coil conductor patterns Lf, Lf1, Lf2 ... inductor RC1 ... primary side resonance circuit by conductive member 20 RC2 ... secondary side resonance circuit Rx ... reception signal input port SC ... shield conductors T1, T2 ... terminal TG ... ground terminal Tx ... transmission signal output port 1 ... primary side circuit 2 ... secondary side circuit 3 ... magnetic coupling element 4 ... Capacitive coupling circuit 5 ... Circuit board 9 ... Transceiver IC
20 ... conductive members 20F, 21F ... metal portions 20L, 20L1, 20L2 ... loop conductors 101A, 101B, 102A, 102B, 104A, 104B, 106, 107, 108 ... antenna device

Claims (7)

  1. 　近傍界通信で用いられるアンテナ装置であって、
    　リーダーライター機能を有する通信回路に接続され、１次コイルを有する１次側回路と、
    　導電性部材と２次コイルと２次側キャパシタとを有する２次側回路と、
    　を備え、
    　前記１次コイルと前記２次コイルとは磁界結合し、
    　前記導電性部材、前記２次コイルおよび前記２次側キャパシタは、互いに並列接続されて、２つの分岐点を有し、
    　前記並列接続の前記２つの分岐点からみて、前記２次コイルを通る電流経路のリアクタンスは誘導性であり、
    　前記２次コイルのインダクタンスは前記導電性部材のインダクタンスよりも大きく、
    　前記導電性部材のインダクタンスと前記２次側キャパシタとは２次側共振回路を構成し、
    　前記導電性部材に流れる電流により発生する磁界によって通信相手側アンテナと磁界結合する、
    　ことを特徴とするアンテナ装置。     An antenna device used in near field communication,
    A primary circuit connected to a communication circuit having a reader / writer function and having a primary coil;
    A secondary circuit having a conductive member, a secondary coil, and a secondary capacitor;
    With
    The primary coil and the secondary coil are magnetically coupled,
    The conductive member, the secondary coil, and the secondary capacitor are connected in parallel to each other and have two branch points,
    As seen from the two branch points of the parallel connection, the reactance of the current path through the secondary coil is inductive,
    The inductance of the secondary coil is larger than the inductance of the conductive member,
    The inductance of the conductive member and the secondary capacitor constitute a secondary resonance circuit,
    Magnetically coupled to the communication partner antenna by a magnetic field generated by a current flowing through the conductive member,
    An antenna device characterized by that.
  2. 　前記１次側回路は１次側キャパシタを更に有し、
    　前記１次側キャパシタは、前記１次コイルに直列接続され、
    　前記１次コイルと前記１次側キャパシタとで１次側共振回路を構成する、
    　請求項１に記載のアンテナ装置。     The primary side circuit further includes a primary side capacitor;
    The primary capacitor is connected in series to the primary coil;
    The primary coil and the primary capacitor constitute a primary resonance circuit.
    The antenna device according to claim 1.
  3. 　前記近傍界通信の通信周波数帯の中心周波数は、前記１次側共振回路と前記２次側共振回路とが結合して構成される結合共振回路により生じる２つの共振周波数の間にある、
    　請求項２に記載のアンテナ装置。     The center frequency of the communication frequency band of the near-field communication is between two resonance frequencies generated by a coupled resonance circuit configured by coupling the primary side resonance circuit and the secondary side resonance circuit.
    The antenna device according to claim 2.
  4. 　筐体導体部を有する筐体を更に備え、
    　前記導電性部材の一部または全部は前記筐体導体部である、
    　請求項１から３のいずれかに記載のアンテナ装置。     A housing having a housing conductor,
    Part or all of the conductive member is the housing conductor.
    The antenna device according to claim 1.
  5. 　積層型チップ部品を更に有し、
    　前記１次コイルと前記２次コイルは、前記積層型チップ部品に一体的に形成され、
    　前記積層型チップ部品は磁性層を有する、
    　請求項１から４のいずれかに記載のアンテナ装置。     It further has a multilayer chip component,
    The primary coil and the secondary coil are formed integrally with the multilayer chip component,
    The multilayer chip component has a magnetic layer,
    The antenna device according to claim 1.
  6. 　前記１次側回路は、高周波ノイズを遮断するインダクタを更に有する、
    　請求項１から５のいずれかに記載のアンテナ装置。     The primary side circuit further includes an inductor that blocks high-frequency noise;
    The antenna device according to claim 1.
  7. 　近傍界通信で用いられるアンテナ装置、および筐体導体部を有する筐体を備える電子機器であって、
    　前記アンテナ装置は、
    　リーダーライター機能を有する通信回路に接続され、１次コイルを有する１次側回路と、
    　前記筐体導体部を含む導電性部材と２次コイルと２次側キャパシタとを有する２次側回路と、
    　を備え、
    　前記１次コイルと前記２次コイルとは磁界結合し、
    　前記導電性部材、前記２次コイルおよび前記２次側キャパシタは、互いに並列接続されて、２つの分岐点を有し、
    　前記並列接続の２つの分岐点からみて、前記２次コイルを通る電流経路のリアクタンスは誘導性であり、
    　前記２次コイルのインダクタンスは前記導電性部材のインダクタンスよりも大きく、
    　前記導電性部材のインダクタンスと前記２次側キャパシタとは２次側共振回路を構成し、
    　前記導電性部材に流れる電流により発生する磁界によって通信相手側アンテナと磁界結合する、
    　ことを特徴とする電子機器。     An antenna device used in near-field communication, and an electronic device including a housing having a housing conductor,
    The antenna device is
    A primary circuit connected to a communication circuit having a reader / writer function and having a primary coil;
    A secondary circuit having a conductive member including the housing conductor, a secondary coil, and a secondary capacitor;
    With
    The primary coil and the secondary coil are magnetically coupled,
    The conductive member, the secondary coil, and the secondary capacitor are connected in parallel to each other and have two branch points,
    When viewed from the two branch points of the parallel connection, the reactance of the current path through the secondary coil is inductive,
    The inductance of the secondary coil is larger than the inductance of the conductive member,
    The inductance of the conductive member and the secondary capacitor constitute a secondary resonance circuit,
    Magnetically coupled to the communication partner antenna by a magnetic field generated by a current flowing through the conductive member,
    An electronic device characterized by that.
PCT/JP2018/007489 2017-03-29 2018-02-28 Antenna device and electronic instrument WO2018180149A1 (en)

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EP1760629A2 (en) * 2005-09-05 2007-03-07 Sony Ericsson Mobile Communications Japan, Inc. Reader/writer and communication method thereof
JP2009171070A (en) * 2008-01-11 2009-07-30 Sony Corp Antenna module, communication equipment, and communication system
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