JP2018170679A - ANTENNA DEVICE AND ELECTRONIC DEVICE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of communication characteristics due to a magnitude relationship between an antenna conductor and a mating antenna conductor. An antenna device 1 is used for wireless communication with an external device as a communication partner. The antenna device 1 includes a loop-shaped antenna conductor 3 and a magnetic material 6. The antenna conductor 3 is wound at least once. The width between the outer peripheral edges 33 of the antenna conductor 3 in at least one direction when viewed in the direction of the winding axis P1 of the antenna conductor 3 is smaller than the width of the other side opening of the other side antenna conductor of the external device. The magnetic body 6 is located between the other side antenna conductor 94 and the antenna conductor 3 in the direction of the winding axis P1 of the antenna conductor 3, is provided on the antenna conductor 3, and is wound on the antenna conductor 3. It is provided so as to overlap at least the inner peripheral edge 32 of the antenna conductor 3 when viewed in the direction of the rotation axis P1. [Selection diagram] Fig. 1

Description

  The present invention relates to an antenna device and an electronic apparatus.

  Conventionally, various antenna elements used for short-range wireless communication are known (see, for example, FIG. 8 of Patent Document 1).

  The antenna element described in Patent Document 1 is used in a mobile communication terminal that communicates with a reader / writer, and includes an antenna coil having an opening. Since the opening of the antenna coil described in Patent Document 1 is substantially the same size as the opening of the antenna coil of the reader / writer, when short-range wireless communication is performed, the antenna coil of the mobile communication terminal and the antenna of the reader / writer The coils face each other.

Japanese Patent Laid-Open No. 2014-23012

  By the way, when communicating between a reader / writer (external device) such as a smartphone and a small device (electronic device) such as a wearable device (for example, a wireless earphone), the antenna conductor used in the small device is the antenna conductor of the reader / writer. It becomes smaller than (mating antenna conductor).

  Due to the size relationship between the antenna conductor of the small device and the counterpart antenna conductor, there is a problem that communication may be difficult when the small device communicates with the reader / writer.

  The present invention is an invention made in view of the above points, and an object of the present invention is an antenna device capable of preventing communication characteristics from deteriorating due to the magnitude relationship between the antenna conductor and the counterpart antenna conductor, And it is providing an electronic device provided with this antenna device.

  The antenna device according to one embodiment of the present invention is used to perform wireless communication with an external device that is a communication partner. The external device includes a loop-shaped counterpart antenna conductor having a counterpart opening. The antenna device includes a loop-shaped antenna conductor and a magnetic body. The antenna conductor is wound at least once. When viewed in the direction of the winding axis of the antenna conductor, the width between the outer peripheral edges of the antenna conductor in at least one direction is smaller than the width of the counterpart opening. The magnetic body is located between the counterpart antenna conductor and the antenna conductor in the direction of the winding axis of the antenna conductor, is provided on the antenna conductor, and is wound around the antenna conductor. It is provided so as to overlap at least the inner periphery of the antenna conductor when viewed in the axial direction.

  An electronic device according to one embodiment of the present invention includes the antenna device and the housing. The housing houses the antenna device.

  According to the antenna device and the electronic apparatus according to the above aspect of the present invention, it is possible to prevent the communication characteristics from being deteriorated due to the magnitude relationship between the antenna conductor and the counterpart antenna conductor.

FIG. 1A is a front view of an antenna device according to Embodiment 1 of the present invention. 1B is a cross-sectional view taken along line A1-A1 of FIG. 1A. FIG. 2 is an exploded perspective view of the antenna device. FIG. 3 is a front view of the antenna device when the above is operating. 4 is a cross-sectional view taken along line A2-A2 of FIG. FIG. 5 is a distribution diagram showing a magnetic flux distribution during the operation of the antenna device. FIG. 6A is a front view of an antenna device according to Modification 1 of Embodiment 1 of the present invention. 6B is a cross-sectional view taken along line A3-A3 of FIG. 6A. FIG. 7A is a front view of an antenna device according to Modification 2 of Embodiment 1 of the present invention. 7B is a cross-sectional view taken along line A4-A4 of FIG. 7A. FIG. 8 is a distribution diagram showing the magnetic flux distribution during the operation of the antenna device. FIG. 9A is a cross-sectional view of an antenna device according to Modification 3 of Embodiment 1 of the present invention. FIG. 9B is a cross-sectional view of the antenna device according to Modification 4 of Embodiment 1 of the present invention. FIG. 10A is a cross-sectional view of an antenna device according to Modification 5 of Embodiment 1 of the present invention. FIG. 10B is a cross-sectional view of the antenna device according to Modification 6 of Embodiment 1 of the present invention. FIG. 10C is a cross-sectional view of the antenna device according to Modification 7 of Embodiment 1 of the present invention. FIG. 10D is a cross-sectional view of the antenna device according to Modification 8 of Embodiment 1 of the present invention. FIG. 11A is a cross-sectional view of the antenna device according to Embodiment 2 of the present invention. FIG. 11B is a side view of the wireless earphone according to the second embodiment of the present invention. 11C is a cross-sectional view taken along line A5-A5 of FIG. 11B. FIG. 12A is a front view of an antenna apparatus according to Embodiment 3 of the present invention. 12B is a cross-sectional view taken along line A6-A6 of FIG. 12A. FIG. 13 is an equivalent circuit diagram of the antenna device according to the third embodiment of the present invention. FIG. 14A is a cross-sectional view of an antenna device according to Modification 1 of Embodiment 3 of the present invention. FIG. 14B is a cross-sectional view of the antenna device according to Modification 2 of Embodiment 3 of the present invention. FIG. 15 is a cross-sectional view of the comparative antenna device during operation. FIG. 16 is a distribution diagram showing a magnetic flux distribution during the operation of the antenna device.

  Hereinafter, antenna devices and electronic devices according to the embodiments will be described in detail with reference to the drawings.

  The “antenna device” shown in each embodiment is an antenna device used to perform near-field communication using a loop-like counterpart antenna conductor and magnetic field coupling. For example, the present invention is applied to a communication system such as NFC (Near Field Communication). That is, the “antenna device” shown in each embodiment is used in a wireless transmission system such as communication using at least magnetic coupling. In addition, the “antenna device” shown in each embodiment includes those that are wirelessly transmitted by electromagnetic field coupling (magnetic field coupling and electric field coupling) substantially with the counterpart antenna conductor.

  The “antenna device” shown in each embodiment uses, for example, the HF band, particularly 13.56 MHz or 6.78 MHz or a frequency band in the vicinity thereof. The size of the antenna device is sufficiently smaller than the wavelength λ at the used frequency, and the radiation efficiency of electromagnetic waves is low in the used frequency band. The size of the antenna device is λ / 10 or less. More specifically, the length of the current path of the antenna device is λ / 10 or less. In addition, the wavelength here is an effective wavelength in consideration of the wavelength shortening effect due to the dielectric property and permeability of the base material on which the conductor is formed.

  The “electronic device” shown in each embodiment is a small device such as an earphone or an RFID tag. An example of an earphone used as an electronic device in each embodiment is a wireless earphone, but is not limited to a wireless earphone.

(Embodiment 1)
(1) Overall Configuration of Antenna Device Hereinafter, an antenna device according to Embodiment 1 will be described in detail with reference to the drawings.

  As shown in FIGS. 1A, 1B, and 2, the antenna device 1 according to the first embodiment includes a base material 2, a loop-shaped antenna conductor (coil conductor) 3, and two connection terminals (first connection terminals 41). , Second connection terminal 42), protective layer 5, and magnetic body 6. In FIG. 1B, the thickness of each part is exaggerated. The same applies to other sectional views.

  The antenna device 1 is used for wireless communication with an external device 9 (see FIGS. 3 and 4). The antenna device 1 is used by being incorporated in an electronic device 7 (see FIGS. 3 and 4) that is smaller than the external device 9.

  The communication between the electronic device 7 incorporating the antenna device 1 and the external device 9 is, for example, communication for the purpose of authentication between the electronic device 7 incorporating the antenna device 1 and the external device 9.

(2) External Device Next, the external device 9 that is a communication partner of the antenna device 1 will be described with reference to FIGS. 3 and 4.

  The external device 9 includes a counterpart antenna device 91 and a counterpart housing 92 that accommodates the counterpart antenna device 91. The counterpart antenna device 91 includes a base material 93, a loop-like counterpart antenna conductor 94, two connection terminals 951 and 952, and a protective layer 96. The counterpart antenna conductor 94 has a counterpart opening 97. The counterpart antenna conductor 94 is a planar coil in which a conductor is wound a plurality of times so as to form a square frame, for example.

  The external device 9 is, for example, a mobile phone (including a smartphone), a wearable terminal (such as a smart watch), a notebook computer, a tablet terminal, a PDA, a camera, or a game machine.

(3) Each component of antenna apparatus Next, each component of the antenna apparatus 1 is demonstrated in detail with reference to drawings.

  As shown in FIG. 2, the base material 2 is a square flat plate made of an insulating material such as a resin. For example, the base material 2 is polyimide, PET (Poly Ethylene Terephthalate) or liquid crystal polymer (LCP).

  The antenna conductor 3 is used for near field communication using magnetic field coupling with the counterpart antenna conductor 94 (see FIG. 3) of the external device 9. The antenna conductor 3 is a conductor such as copper or aluminum. As shown in FIGS. 1A, 1B, and 2, the antenna conductor 3 has a conductor along a plane orthogonal to the winding axis P1, for example, in a square frame shape. A planar coil wound a plurality of times. The antenna conductor 3 has an opening 31 (first opening), and is provided on the first main surface 21 of the substrate 2 in a spiral shape. More specifically, the antenna conductor 3 is wound on the first main surface 21 of the base material 2 a plurality of times in the counterclockwise direction when viewed from the first main surface 21 side around the winding axis P1. It is configured. The outer peripheral edge 33 of the antenna conductor 3 is located on the inner side of the outer peripheral edge of the substrate 2 in a plan view from the direction of the winding axis P1. Here, the spiral antenna may be a two-dimensional antenna in which a conductor is wound a plurality of times on one plane orthogonal to the winding axis, or the conductor is not spiral along the winding axis. It may be a three-dimensional antenna that is wound a plurality of times.

  In the region where the antenna conductor 3 is provided, the inner peripheral edge of the innermost conductor portion of the antenna conductor 3 is referred to as the inner peripheral edge 32 of the antenna conductor 3. The peripheral edge is referred to as the outer peripheral edge 33 of the antenna conductor 3. The antenna conductor 3 is connected to the first connection terminal 41 and the second connection terminal 42.

  Incidentally, as shown in FIGS. 3 and 4, the antenna conductor 3 is smaller than the counterpart antenna conductor 94. The dimension W1 of the antenna conductor 3 (the width between the outer peripheral edges 33) is smaller than the width W2 of the counterpart opening 97 of the counterpart antenna conductor 94. When the center of the opening 31 of the antenna conductor 3 coincides with the center of the counterpart opening 97 of the counterpart antenna conductor 94, a gap Wg is formed between the antenna conductor 3 and the counterpart antenna conductor 94 around the antenna conductor 3. Occurs.

  A first connection terminal 41 and a second connection terminal 42 shown in FIGS. 1A and 2 are conductor patterns for connecting an external circuit such as an RFIC and the antenna conductor 3. The planar shape of the first connection terminal 41 is a square shape, and the first connection terminal 41 is connected to the inner peripheral end of the antenna conductor 3. The planar shape of the second connection terminal is rectangular, and the second connection terminal 42 is formed at the outer peripheral end of the antenna conductor 3.

  The protective layer 5 shown in FIGS. 1B and 2 is formed of an insulating material such as a resin, for example, and protects the base material 2 and the antenna conductor 3 from an external force or the like. The planar shape of the protective layer 5 is substantially the same as that of the substrate 2. The insulating material forming the protective layer 5 is, for example, polyimide or liquid crystal polymer (LCP). The protective layer 5 is affixed to the first main surface 21 of the substrate 2 via an adhesive layer (not shown).

  As shown in FIG. 1B, the magnetic body 6 is provided on the second main surface 22 opposite to the first main surface 21 of the substrate 2 in the direction of the winding axis P <b> 1 of the antenna conductor 3. In other words, as shown in FIG. 4, the magnetic body 6 includes the antenna conductor 3 and the counterpart antenna conductor 94 when the antenna conductor 3 and the counterpart antenna conductor 94 face each other in the direction of the winding axis P <b> 1 of the antenna conductor 3. It is provided so that it may be located between. That is, the magnetic body 6 is provided on the side where the antenna conductor 3 faces the counterpart antenna conductor 94 with respect to the antenna conductor 3 in the direction of the winding axis P <b> 1 of the antenna conductor 3. In other words, the magnetic body 6 is located between the counterpart antenna device 91 and the antenna conductor 3 in the direction of the winding axis P <b> 1 of the antenna conductor 3, and is provided on the antenna conductor 3. Here, “provided on the antenna conductor 3” means indirectly on the substrate 2, the protective layer 5, etc. covering the antenna conductor 3, in addition to being directly provided on the antenna conductor 3. The state where it is provided is also included.

  The magnetic body 6 is made of a ferromagnetic material such as ferrite. The magnetic body 6 has a higher magnetic permeability than the base material 2 and the protective layer 5. The ferromagnetic material used for the magnetic body 6 is, for example, Ni—Zn—Cu ferrite or hexagonal ferrite. The thickness of the magnetic body 6 is, for example, 200 [μm] to 300 [μm].

  As shown in FIG. 1A, the magnetic body 6 has a square shape and is provided between the antenna conductor 3 and the counterpart antenna conductor 94 over the entire circumference of the antenna conductor 3. That is, the magnetic body 6 is provided on the entire second main surface 22. In other words, the magnetic body 6 is provided between the antenna conductor 3 and the counterpart antenna conductor 94 in all directions orthogonal to the winding axis P1.

(4) Description at the time of communication of the antenna device Next, a case where the electronic device 7 including the antenna device 1 according to the first embodiment communicates with the external device 9 will be described with reference to FIGS. 3 and 4. As a comparative example, the operation of the antenna device 100 in which the magnetic body 600 is provided on the opposite side of the counterpart antenna conductor 94 with respect to the antenna conductor 300 as shown in FIG. The antenna device 100 of the comparative example is built in the electronic device 700.

  First, the electronic device 7 is brought close to the external device 9 so that the antenna conductor 3 of the electronic device 7 according to the first embodiment and the counterpart antenna conductor 94 of the external device 9 face each other. At this time, the winding axis P1 of the antenna conductor 3 is along the winding axis of the counterpart antenna conductor 94 of the external device 9 and in the plan view from the direction of the winding axis P1, the opening 31 of the antenna conductor 3 The electronic device 7 is brought close to the external device 9 so that the counterpart opening 97 of the counterpart antenna conductor 94 overlaps with each other.

  Thereafter, when a current flows through the counterpart antenna conductor 94 of the external device 9 in order for the external device 9 to communicate with the electronic device 7, a magnetic flux passing through the counterpart opening 97 of the counterpart antenna conductor 94 is generated. Of the magnetic flux generated in the counterpart antenna conductor 94, the magnetic flux φ <b> 1 passes outside the antenna conductor 3. On the other hand, among the magnetic fluxes generated by the counterpart antenna conductor 94, the magnetic flux φ <b> 2 passes through the counterpart antenna conductor 94 side of the opening 31 of the antenna conductor 3.

  As described above, the magnetic body 6 having higher magnetic permeability than the base material 2 and the protective layer 5 is provided between the antenna conductor 3 and the counterpart antenna conductor 94. For this reason, the magnetic flux φ2 does not pass through the opening 31 of the antenna conductor 3, but passes through the periphery of the antenna conductor 3 so as to go from the center side of the antenna conductor 3 to the outside through the inside of the magnetic body 6. That is, as shown in FIG. 4, the magnetic body 6 changes the direction of the magnetic flux φ2. Thereby, the magnetic flux φ3 passing through the opening 31 of the antenna conductor 3 can be reduced.

  The induced current induced in the antenna conductor 3 by the magnetic flux φ1 passing outside the antenna conductor 3, and the magnetic flux φ2 passing through the periphery of the antenna conductor 3 from the center side of the antenna conductor 3 through the inside of the magnetic body 6 Are induced in the antenna conductor 3 in the same direction. On the other hand, the induced current induced by the magnetic flux φ3 shown in FIG. 4 is in the opposite direction to the induced current induced by the magnetic fluxes φ1 and φ2. That is, since the magnetic body 6 is provided between the antenna conductor 3 and the counterpart antenna conductor 94, the magnetic body 6 is not provided between the antenna conductor 3 and the counterpart antenna conductor 94. Thus, since the magnetic flux φ3 passing through the opening 31 of the antenna conductor 3 is reduced and the magnetic flux φ2 passing through the inside of the magnetic body 6 is increased, the induced current caused by the magnetic flux φ1 is prevented from being canceled by the reverse induced current caused by the magnetic flux φ3. it can. This makes it difficult to reduce the induced current induced in the antenna conductor 3, and the induced current in the same direction is generated in the antenna conductor 3 by the magnetic flux φ1 and the magnetic flux φ2, so that the induced current induced in the antenna conductor 3 is reduced. Therefore, when the external device 9 and the electronic device 7 communicate with each other, desired communication characteristics can be ensured.

  FIG. 5 shows a simulation result of magnetic flux distribution in the antenna device 1 according to the first embodiment. Also in the simulation result, it is clear that the magnetic flux distribution is as described above. The magnetic flux above the center of the antenna conductor 3 changes its direction to the outside of the antenna conductor 3 by the magnetic body 6 and passes outside the antenna conductor 3. As a result, the magnetic flux is counterclockwise around the antenna conductor 3, and it can be suppressed that the induced current caused by the magnetic flux φ <b> 1 passing outside the antenna conductor 3 is canceled.

  Next, the antenna device 100 of the comparative example will be described. When a current flows through the counterpart antenna conductor 94 of the external device 9 in order for the external device 9 to communicate with the electronic device 700, a magnetic flux passing through the counterpart opening 97 of the counterpart antenna conductor 94 is generated. Of the magnetic flux generated in the counterpart antenna conductor 94, the magnetic flux φ <b> 11 passes outside the antenna conductor 300. On the other hand, of the magnetic flux generated by the counterpart antenna conductor 94, the magnetic flux φ 3 passes through the opening 310 of the antenna conductor 300.

  FIG. 16 shows a simulation result of magnetic flux distribution in the antenna device 100 of the comparative example. In the case of the antenna device 100 of the comparative example, the magnetic body 600 is provided on the opposite side of the antenna conductor 300 from the counterpart antenna conductor 94 (see FIG. 15). Both the magnetic flux φ13 passing through the opening 310 of the conductor 300 also passes from the upper side to the lower side. For this reason, the induced current induced in the antenna conductor 300 is in the opposite direction and is canceled and reduced.

  Next, the positional relationship between the antenna conductor 3 of the antenna device 1 according to the first embodiment and the counterpart antenna conductor 94 of the external device 9 and whether communication is possible will be described with reference to FIGS. 3 and 4.

  The dimension W1 (width between the outer peripheral edges 33) of the antenna conductor 3 is 8 [mm], and the width W2 of the counterpart opening 97 of the counterpart antenna conductor 94 is 40 [mm]. The center of the counterpart opening 97 of the counterpart antenna conductor 94 is defined as the origin O of the X and Y coordinates. The values of X and Y indicate the shift amount of the center of the opening 31 of the antenna conductor 3 with respect to the center of the counterpart opening 97 of the counterpart antenna conductor 94. For example, when X = 2 and Y = 0, the center of the opening 31 of the antenna conductor 3 is shifted by 2 [mm] in the positive direction of the X axis with respect to the center of the counterpart opening 97 of the counterpart antenna conductor 94. Indicates.

  Table 1 shows the result of communication availability in the positional relationship between the antenna conductor 3 of the antenna device 1 according to the first embodiment and the counterpart antenna conductor 94 of the external device 9. Table 2 shows the result of whether communication is possible or not in the positional relationship between the antenna device 100 and the counterpart antenna conductor 94 of the external device 9 in which the magnetic body is not provided between the antenna conductor 300 and the counterpart antenna conductor 94 of the comparative example. Indicates. In both Table 1 and Table 2, the symbol “◯” represents communication success, and the symbol “×” represents communication failure.

  In the case of the antenna device 1 according to Embodiment 1, as shown in Table 1, the opening 31 of the antenna conductor 3 with respect to the center of the counterpart opening 97 of the counterpart antenna conductor 94 in both the X-axis direction and the Y-axis direction. In the range where the center shift amount is 2 [mm] or less, all communications are successful. On the other hand, in the case of the antenna device 100 of the comparative example, as shown in Table 2, the shift amount of the center of the opening 310 of the antenna conductor 300 with respect to the center of the counterpart opening 97 of the counterpart antenna conductor 94 is in a range of 2 [mm] or less. Then, it is all communication failure. From the above, it can be said that the desired communication characteristics can be secured by providing the magnetic body 6 between the antenna conductor 3 and the counterpart antenna conductor 94.

(5) Effect As described above, in the antenna device 1 according to the first embodiment, the magnetic body 6 is disposed between the counterpart antenna conductor 94 and the antenna conductor 3 in the direction of the winding axis P1 of the antenna conductor 3. Located on the antenna conductor 3. Further, the magnetic body 6 is provided so as to overlap at least the inner peripheral edge 32 of the antenna conductor 3 when viewed in the direction of the winding axis P <b> 1 of the antenna conductor 3. Thereby, when the antenna conductor 3 and the counterpart antenna conductor 94 face each other so that the antenna conductor 3 overlaps the counterpart opening 97 of the counterpart antenna conductor 94, the direction of the magnetic flux φ2 generated in the counterpart antenna conductor 94 is changed. It can be changed by the magnetic body 6. As a result, it can be suppressed that the induced current caused by the magnetic flux φ1 passing outside the antenna conductor 3 is canceled by the reverse induced current caused by the magnetic flux φ3 passing near the inner periphery 32 of the antenna conductor 3. That is, it is possible to suppress the reduction of the induced current induced in the antenna conductor 3 by the magnetic flux generated in the counterpart antenna conductor 94. Further, the induced current in the same direction is generated in the antenna conductor 3 by the magnetic flux φ1 and the magnetic flux φ2, and the induced current induced in the antenna conductor 3 can be strengthened. Therefore, the received power extracted from the antenna conductor 3 can be increased.

  Note that “the magnetic body 6 is provided so as to overlap the inner peripheral edge 32” means that not only the inner peripheral edge 32 is covered with the magnetic body 6 but also almost the entire inner peripheral edge 32 (for example, the inner peripheral edge 32). Including a case where 80% or more of 32) is covered with the magnetic body 6.

  In particular, in the antenna device 1 according to the first embodiment, the magnetic body 6 is provided on the entire second main surface 22 located between the antenna conductor 3 and the counterpart antenna conductor 94. Thereby, since the magnetic flux φ3 passing through the opening 31 of the antenna conductor 3 can be further reduced, the magnetic flux φ3 that causes the induced current caused by the magnetic flux φ1 passing outside the antenna conductor 3 to be offset can be further reduced. . As a result, the reduction of the induced current induced in the antenna conductor 3 can be further suppressed.

(6) Modification As a first modification of the first embodiment, the antenna device 1a includes a magnetic body 6a as shown in FIGS. 6A and 6B instead of the magnetic body 6 (see FIGS. 1A and 1B). The magnetic body 6a has an opening 61 (second opening). The opening 61 overlaps at least a part of the opening 31 of the antenna conductor 3 in a plan view from the direction of the winding axis P1 of the antenna conductor 3. That is, the opening 61 is smaller in size than the opening 31 of the antenna conductor 3.

  The magnetic body 6 a is provided in a region between the inner peripheral edge 32 of the antenna conductor 3 and the outer peripheral edge 33 of the antenna conductor 3. The magnetic body 6a is provided so as to include the inner peripheral edge 32 of the antenna conductor 3 in a plan view from the direction of the winding axis P1 of the antenna conductor 3. In short, the magnetic body 6a is located between the area between the inner peripheral edge 32 of the antenna conductor 3 and the outer peripheral edge 33 of the antenna conductor 3 and the counterpart antenna conductor 94 (see FIG. 4) on the winding axis P1. It is provided as follows.

  In the antenna device 1a according to the first modification, the magnetic body 6a is provided between the area between the inner peripheral edge 32 of the antenna conductor 3 and the outer peripheral edge 33 of the antenna conductor 3 and the counterpart antenna conductor 94 (see FIG. 4). It has been. Thereby, since the area | region in which the antenna conductor 3 is provided in the direction of the winding axis P1 of the antenna conductor 3 can be covered with the magnetic body 6a, the induction | guidance | derivation by magnetic flux (phi) 1 (refer FIG. 4) which passes the outer side of the antenna conductor 3 The magnetic flux φ3 that cancels the current can be reduced. As a result, reduction of the induced current induced in the antenna conductor 3 can be suppressed similarly to the antenna device 1.

  Further, in the antenna device 1 a according to the first modification, the antenna conductor 3 has the opening 31 and the magnetic body 6 a has the opening 61. Accordingly, the antenna conductor 3 and the central portion of the magnetic body 6a can be penetrated in the direction of the winding axis P1 of the antenna conductor 3, so that other components can be inserted into the opening 31 and the opening 61, for example. Can increase the degree of freedom. In the example of FIGS. 6A and 6B, the base material 2 and the protective layer 5 do not penetrate and close the opening 31 and the opening 61.

  As a second modification of the first embodiment, the antenna device 1b includes a magnetic body 6b as shown in FIGS. 7A and 7B instead of the magnetic body 6 (see FIGS. 1A and 1B). The magnetic body 6b has a frame shape and is provided between the inner peripheral edge 32 of the antenna conductor 3 and the counterpart antenna conductor 94 (see FIG. 4). In short, the magnetic body 6 b is provided so as to be positioned at least between the inner peripheral edge 32 of the antenna conductor 3 and the counterpart antenna conductor 94.

  FIG. 8 shows a simulation result of magnetic flux distribution in the antenna device 1b according to the second modification. Also in the antenna device 1b according to the modified example 2, the magnetic flux near the center of the antenna conductor 3 changes its direction to the outside of the antenna conductor 3 by the magnetic body 6 and passes outside the antenna conductor 3.

  In the antenna device 1b according to Modification 2, the magnetic body 6b is provided between the inner peripheral edge 32 of the antenna conductor 3 and the counterpart antenna conductor 94 in the direction of the winding axis P1 of the antenna conductor 3. Further, the antenna conductor 3 is provided so as to overlap at least the inner peripheral edge 32 of the antenna conductor 3 when viewed in the direction of the winding axis P1 of the antenna conductor 3. Thereby, the linkage between the magnetic flux from the counterpart antenna conductor 94 (see FIG. 4) passing through the opening 31 of the antenna conductor 3 and the inner peripheral edge 32 of the antenna conductor 3 can be reduced. Therefore, the magnetic flux φ3 (see FIG. 4) that cancels out the induced current caused by the magnetic flux φ1 (see FIG. 4) passing outside the antenna conductor 3 can be reduced, and the induction current induced in the antenna conductor 3 can be reduced. 1 can be suppressed.

  As a third modification of the first embodiment, the antenna device 1c includes a magnetic body 6c as shown in FIG. 9A instead of the magnetic body 6 (see FIG. 1B). The magnetic body 6 c is provided not only on the second main surface 22 of the substrate 2 but also on the side surface 23 of the substrate 2 and the side surface 51 of the protective layer 5.

  Further, as a fourth modification of the first embodiment, the antenna device 1d includes a magnetic body 6d as shown in FIG. 9B instead of the magnetic body 6 (see FIG. 1B). The magnetic body 6d is provided not only on the counterpart antenna conductor 94 (see FIG. 4) side of the antenna conductor 3 but also on the protective layer 5 side. Since the magnetic body 6d is also provided on the protective layer 5 side, the magnetic flux is concentrated inside the antenna conductor 3 if the magnetic flux φ3 (see FIG. 4) passing through the opening 31 of the antenna conductor 3 remains. be able to. Thereby, communication characteristics can be improved. Further, the magnetic flux φ3 (see FIG. 4) for canceling the induced current due to the magnetic flux φ1 (see FIG. 4) passing outside the antenna conductor 3 can be reduced, and the induction current induced in the antenna conductor 3 can be reduced. 1 can be suppressed.

  Furthermore, as modified examples 5 to 8 of the first embodiment, as shown in FIGS. 10A to 10D, the magnetic bodies 6 e to 6 h are provided so as to cover the opening 31 of the antenna conductor 3. That is, the magnetic bodies 6e to 6h are provided so as to overlap with the opening 31 in a plan view from the winding axis P1 of the antenna conductor 3.

  As a fifth modification of the first embodiment, the antenna device 1e includes a magnetic body 6e as shown in FIG. 10A instead of the magnetic body 6 (see FIG. 1B). The magnetic body 6e is provided only between the inner peripheral edge 32 and the opening 31 of the antenna conductor 3 and the counterpart antenna conductor 94 (see FIG. 4). As a sixth modification of the first embodiment, the antenna device 1 f includes a magnetic body 6 f as shown in FIG. 10B instead of the magnetic body 6. The magnetic body 6 f is provided so as to be positioned between the area between the inner peripheral edge 32 of the antenna conductor 3 and the outer peripheral edge 33 of the antenna conductor 3 and the counterpart antenna conductor 94. As a seventh modification of the first embodiment, the antenna device 1g includes a magnetic body 6g as shown in FIG. 10C instead of the magnetic body 6. The magnetic body 6 g is provided not only on the second main surface 22 of the substrate 2 but also on the side surface 23 of the substrate 2 and the side surface 51 of the protective layer 5. As a modification 8 of the first embodiment, the antenna device 1 h includes a magnetic body 6 h as shown in FIG. 10D instead of the magnetic body 6. The magnetic body 6h is provided not only on the counterpart antenna conductor 94 side of the antenna conductor 3 but also on the protective layer 5 side.

  Also in the antenna devices 1e to 1h according to the modified examples 5 to 8, the magnetic flux φ3 (see FIG. 4) passing through the opening 31 of the antenna conductor 3 can be further reduced, and the induction current induced in the antenna conductor 3 can be reduced. It can be suppressed in the same manner as the antenna device 1.

  Note that the magnetic bodies 6a to 6f may not be provided in the entire region between the antenna conductor 3 and the counterpart antenna conductor 94 (see FIG. 4) as in the above-described modifications 1 to 6. That is, the magnetic bodies 6 a to 6 f may not be provided on the entire surface of the second main surface 22 of the substrate 2 but may be provided only on a part of the second main surface 22.

  The magnetic bodies 6 and 6a to 6h may not be provided between the antenna conductor 3 and the counterpart antenna conductor 94 (see FIG. 4) in all directions orthogonal to the winding axis P1 of the antenna conductor 3. That is, the magnetic bodies 6 and 6a to 6h may not be provided in a part around the winding axis P1. For example, the antenna conductor 3 may have a notch or the like.

  The magnetic bodies 6 and 6a to 6h are provided without intersecting with the antenna conductor 3 in a plan view from a direction orthogonal to the winding axis P1. That is, the magnetic bodies 6 and 6a to 6h are provided so as not to pass through the opening 31 of the antenna conductor 3. In other words, the magnetic bodies 6, 6 a to 6 h are disposed between the counterpart antenna conductor 94 and two pairs of antenna conductors 3 that are at least perpendicular to the winding axis P <b> 1 and opposed in two directions perpendicular to each other. What is necessary is just to be provided so that it may be located.

  The antenna conductor 3 is not limited to a planar coil in which the conductor is wound a plurality of times along a plane, and may be an antenna other than the planar coil. For example, the antenna conductor 3 may be a spiral coil wound a plurality of times while the conductor moves in the direction of the winding axis P1 about the winding axis P1. In short, the antenna conductor 3 may be a coil antenna in which the conductor is wound a plurality of times.

  The antenna conductor 3 is not limited to a spiral antenna in which the conductor is wound a plurality of times, and may be an antenna in which the conductor is wound only once (one turn). In short, the antenna conductor 3 may be a loop antenna.

  The planar shape of the base material 2 is not limited to the quadrangular shape, and may be a shape other than the quadrangular shape. For example, the planar shape of the base material 2 may be a polygonal shape, a circular shape, or an elliptical shape.

  The antenna devices 1, 1 a to 1 h may not include the protective layer 5. That is, the protective layer 5 is not an essential configuration.

(Embodiment 2)
In Embodiment 2, a wireless earphone will be described as an example of an electronic device with a built-in antenna device.

  As shown in FIGS. 11A to 11C, the wireless earphone 7k (electronic device) according to the second embodiment includes an antenna device 1k, a casing 71, a circuit board 72, and an earpiece 73.

  The antenna device 1k according to the second embodiment is different from the antenna device 1 according to the first embodiment (see FIG. 1B) in that it is curved. In addition, about the component similar to the antenna apparatus 1 which concerns on Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The antenna device 1k includes a base material 2k, an antenna conductor 3k, a protective layer 5k, and a magnetic body 6k instead of the base material 2, the antenna conductor 3, the protective layer 5, and the magnetic body 6. The base material 2k, the antenna conductor 3k, the protective layer 5k, and the magnetic body 6k are formed in a curved surface shape.

  The casing 71 accommodates the antenna device 1k and the circuit board 72. More specifically, a curved antenna conductor 3k is provided along a curved surface portion that is a part of the casing 71.

  The circuit board 72 includes a plurality of circuit components 74 and a substrate 75 on which the plurality of circuit components 74 are mounted. The circuit board 72 is electrically connected to the antenna conductor 3. The plurality of circuit components 74 are, for example, capacitors for RFIC and resonance circuits. The ear piece 73 is attached to one end of the housing 71.

  Next, the case where the wireless earphone 7k according to the second embodiment communicates with the external device 9 will be described. The communication between the wireless earphone 7k and the external device 9 includes, for example, an authentication connection between the wireless earphone 7k and the external device 9.

  First, the wireless earphone 7k is brought close to the external device 9 so that the antenna conductor 3k of the wireless earphone 7k faces the counterpart antenna conductor 94 (see FIG. 4) of the external device 9 (see FIG. 4). At this time, the wireless earphone 7k is brought close to the external device 9 so that the winding axis P2 of the antenna conductor 3k is along the winding axis of the counterpart antenna conductor 94 of the external device 9.

  Thereafter, when a current flows through the counterpart antenna conductor 94 of the external device 9 in order for the external device 9 to communicate with the wireless earphone 7k, a magnetic flux is generated in the counterpart antenna conductor 94. Of the magnetic flux generated by the counterpart antenna conductor 94, the magnetic flux passing above the antenna conductor 3k passes through the antenna conductor 3k so as to go from the center side of the antenna conductor 3k to the outside through the inside of the magnetic body 6k. That is, the direction of the magnetic flux is changed by the magnetic body 6k. Thereby, the magnetic flux which passes along opening 31k of antenna conductor 3k can be reduced.

  An induced current in the same direction is induced in the antenna conductor 3k by the magnetic flux passing outside the antenna conductor 3k and the magnetic flux whose direction is changed by the magnetic body 6k. That is, since it is possible to suppress the induced current caused by the magnetic flux passing outside the antenna conductor 3k from being canceled by the magnetic flux passing through the opening 31k of the antenna conductor 3k, it is difficult to reduce the induced current induced in the antenna conductor 3k.

  Also in the wireless earphone 7k (electronic device) according to the second embodiment described above, the antenna conductor 3k and the counterpart antenna when the antenna conductor 3k and the counterpart antenna conductor 94 face each other in the direction of the winding axis P2 of the antenna conductor 3k. A magnetic body 6k is provided so as to be positioned between the conductor 94. Thereby, when the antenna conductor 3k and the counterpart antenna conductor 94 face each other so that the opening 31 of the antenna conductor 3k overlaps the counterpart opening 97 of the counterpart antenna conductor 94, the magnetic flux generated in the counterpart antenna conductor 94 is reduced. The direction can be changed by the magnetic body 6k. As a result, it is possible to suppress the magnetic flux passing outside the antenna conductor 3k from being canceled by the magnetic flux passing through the opening 31k of the antenna conductor 3k. That is, reduction of the induced current induced in the antenna conductor 3k by the magnetic flux generated in the counterpart antenna conductor 94 can be suppressed similarly to the antenna device 1.

  In the antenna device 1k according to the second embodiment, the antenna conductor 3k and the magnetic body 6k are formed in a curved shape. Thereby, the freedom degree of mounting of antenna device 1k can be raised. For example, the antenna device 1k can be attached to the curved surface of the casing 71 as in the second embodiment.

  As a modification of the second embodiment, the wireless earphone 7k may include the antenna device 1 according to the first embodiment (see FIG. 1B) instead of the antenna device 1k. Alternatively, the wireless earphone 7k replaces the antenna device 1k with the antenna devices 1a to 1h according to the first to eighth modifications of the first embodiment (see FIGS. 6B, 7B, 9A, 9B, and 10A to 10D). Either of these may be provided.

(Embodiment 3)
In Embodiment 3, an antenna device in which a booster antenna is mounted together with an antenna will be described.

  The antenna device 1m according to the third embodiment is different from the antenna device 1 according to the first embodiment (see FIGS. 1A and 1B) in that a booster antenna 8 is provided as shown in FIGS. 12A and 12B. In addition, about the component similar to the antenna apparatus 1 which concerns on Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The booster antenna 8 is provided adjacent to the antenna conductor 3m. The booster antenna 8 is provided on the first main surface 21 of the base material 2 together with the antenna conductor 3m. More specifically, the booster antenna 8 is provided outside the outer peripheral edge 33m of the antenna conductor 3m so as to be adjacent to the antenna conductor 3m on a plane orthogonal to the winding axis P3 of the antenna conductor 3m. The booster antenna 8 is provided on the base material 2 so that the winding axis of the booster antenna 8 coincides with the winding axis P3 of the antenna conductor 3m.

  The booster antenna 8 includes a frame-shaped coil conductor 81 as an inductor and a capacitor 82. The booster antenna 8 is configured to be magnetically coupled to the antenna conductor 3m. The number of turns of the coil conductor 81 of the booster antenna 8 is smaller than the number of turns of the antenna conductor 3m.

  The antenna conductor 3m of Embodiment 3 is a planar coil in which a conductor is wound a plurality of times along a plane orthogonal to the winding axis P3. The antenna conductor 3m has an opening 31m and is provided in a spiral shape on the first main surface 21 of the base material 2 in the same manner as the antenna conductor 3 of Embodiment 1 (see FIGS. 1A and 1B). However, as described above, since the base material 2 is provided with the booster antenna 8, the antenna conductor 3m is smaller than the antenna conductor 3 of the first embodiment. Note that a description of the same functions as those of the antenna conductor 3 of Embodiment 1 is omitted.

  The magnetic body 6m of Embodiment 3 is provided on the entire surface of the second main surface 22 of the substrate 2 including the region from the inner peripheral edge 32m of the antenna conductor 3m to the outer peripheral edge 33m of the antenna conductor 3m. In addition, description is abbreviate | omitted about the function similar to the magnetic body 6 (refer FIG. 1A and FIG. 1B) of Embodiment 1. FIG.

  FIG. 13 is an equivalent circuit diagram of the antenna device 1m. As shown in FIG. 13, the inductive component L1 of the antenna conductor 3m is a primary coil, and the inductive component L2 of the booster antenna 8 is a secondary coil. On the primary side, the induction component L1 of the antenna conductor 3m is connected in parallel with the capacitance component C1 of the capacitor. On the secondary side, the inductive component L 2 of the booster antenna 8 is connected in parallel with the capacitance component C 2 of the capacitor 82. The resonance frequency of the antenna device 1b according to the third embodiment is determined by the primary-side inductive component L1 and the capacitive component C1, and the secondary-side inductive component L2 and the capacitive component C2.

  Further, since the booster antenna 8 is arranged along the outer peripheral edge 33m of the antenna conductor 3m with the winding axis coincided with the antenna conductor 3m, a high coupling coefficient is realized between the antenna conductor 3m and the coil conductor 81. can do.

  Furthermore, since the turns ratio (secondary turns ratio) of the coil conductor 81 of the booster antenna 8 is smaller than the turns ratio (primary turns ratio) of the antenna conductor 3m, the secondary induction component L2 is the primary. It becomes smaller than the induction component L1 on the side. As a result, the voltage on the booster antenna 8 side is lowered, and the current flowing through the booster antenna 8 is increased. As a result, the magnetic flux generated in the coil conductor 81 of the booster antenna 8 increases.

  When the magnetic flux generated in the external device 9 (see FIG. 4) on the communication partner side is linked to the booster antenna 8, an induced current is induced in the booster antenna 8. Magnetic flux is generated in the booster antenna 8 by the induced current. When the magnetic flux of the booster antenna 8 is linked to the antenna conductor 3m, the antenna conductor 3m and the booster antenna 8 are magnetically coupled. As a result, an induced electromotive force is generated in the antenna conductor 3m, and a high frequency current (high frequency signal) flows.

  In the antenna device 1m according to the third embodiment described above, the booster antenna 8 including the inductor (coil conductor 81) is provided adjacent to the antenna conductor 3m. Thereby, the booster antenna 8 is magnetically coupled to the antenna conductor 3m, the magnetic flux generated in the booster antenna 8 is linked to the antenna conductor 3m, and the current flowing through the antenna conductor 3m can be increased. Therefore, it is possible to improve the communication characteristics while reducing the size of the antenna device 1m.

  The coil conductor 81 of the booster antenna 8 is not limited to being wound only once, and may be wound a plurality of times. However, the number of turns of the coil conductor 81 is preferably smaller than the number of turns of the antenna conductor 3m.

  Further, the booster antenna 8 may not include the capacitor 82. The capacitor 82 is not essential, and the booster antenna 8 only needs to include at least the coil conductor 81 as an inductor.

  The booster antenna 8 may not be provided adjacent to the antenna conductor 3m on a plane orthogonal to the winding axis P3 of the antenna conductor 3m. For example, as shown in FIG. 14A, as a first modification, the booster antenna 8 may be provided adjacent to the outer peripheral edge 33m of the antenna conductor 3m in the direction of the winding axis P3. Or as shown in FIG. 14B, as the modification 2, the booster antenna 8 may be provided in the diagonally outer side of the outer periphery 33m of the antenna conductor 3m. However, it is preferable that the booster antenna 8 is provided outside the outer peripheral edge 33m of the antenna conductor 3m.

  As a modification of the third embodiment, the booster antenna 8 includes antenna devices 1a to 1h according to the first to eighth modifications of the first embodiment (see FIGS. 6A, 7A, 9A, 9B, and 10A to 10D). ). Alternatively, the booster antenna 8 may be applied to the antenna device 1k (see FIG. 11A) according to the second embodiment.

(Summary)
As is clear from the embodiments and modifications described above, the antenna devices 1; 1a to 1h; 1k; 1m according to the first aspect are used for wireless communication with the external device 9 that is a communication partner. The external device 9 includes a loop-like counterpart antenna conductor 94 having a counterpart opening 97. The antenna device 1; 1a to 1h; 1k; 1m includes a loop-shaped antenna conductor 3; 3k; 3m and a magnetic body 6; 6a to 6h; 6k; The antenna conductors 3; 3k; 3m are wound at least once. The width (dimension W1) between the antenna conductor 3; 3k; 3m outer peripheral edge 33; 33m in at least one direction when viewed in the direction of the winding axis P1; P2; P3 of the antenna conductor 3; It is smaller than the width W2 of the opening 97. Magnetic body 6; 6a to 6h; 6k; 6m are arranged between the antenna conductor 94 and the antenna conductor 3; 3k; 3m in the direction of the winding axis P1; P2; P3 of the antenna conductor 3; And located on the antenna conductor 3; 3k; 3m, and at least within the antenna conductor 3; 3k; 3m when viewed in the direction of the winding axis P1; P2; P3 of the antenna conductor 3; 3k; The peripheral edge 32 is provided so as to overlap with 32 m.

  In the antenna device 1 according to the first aspect; 1a to 1h; 1k; 1m, the antenna conductor 3; 3k; 3m winding axis P1; P2; Magnetic bodies 6; 6a to 6h; 6k; 6m are provided on the side where 3; 3k; 3m faces the counterpart antenna conductor 94. Thus, when the antenna conductor 3; 3k; 3m and the counterpart antenna conductor 94 face each other so that the antenna conductor 3; 3k; 3m opening 31; 31k; 31m overlaps the counterpart opening 97 of the counterpart antenna conductor 94. In addition, the direction of the magnetic flux φ2 generated in the counterpart antenna conductor 94 can be changed by the magnetic bodies 6; 6a to 6h; 6k; 6m. As a result, it can be suppressed that the induced current caused by the magnetic flux φ1 passing outside the antenna conductor 3; 3k; 3m is canceled by the induced current caused by the magnetic flux φ3 passing through the antenna conductor 3; 3k; 3m opening 31; 31k; 31m. That is, it is possible to suppress a reduction in the induced current induced in the antenna conductors 3; 3k; 3m by the magnetic flux generated in the counterpart antenna conductor 94. Therefore, the received power extracted from the antenna conductors 3; 3k; 3m can be increased.

  In the first embodiment, the magnetic body 6; 6a; 6c; 6d; 6f-6h; 6k; 6m is the antenna device 1; 1a; 1c; 1d; 1f-1h; In the direction of the winding axis P1; P2; P3 of the antenna conductor 3; 3k; 3m, the antenna conductor 3 is located between the antenna conductor 94 and the antenna conductor 3; 3k; 3m, and is provided on the antenna conductor 3; 3k; Antenna conductor 3; 3k; 3m winding axis P1, P2; P3; antenna conductor 3; 3k; 3m inner periphery 32; 32m and antenna conductor 3; 3k; It is provided so as to overlap with the area between the peripheral edge 33 and 33 m.

  In the antenna device 1 according to the second aspect; 1a to 1h; 1k; 1m, between the antenna conductor 3; 3k; 3m inner peripheral edge 32; 32m and the antenna conductor 3; 3k; 3m outer peripheral edge 33; Magnetic bodies 6; 6a; 6c; 6d; 6f to 6h; 6k; 6m are provided between the region and the counterpart antenna conductor 94. As a result, the regions where the antenna conductors 3; 3k; 3m are provided in the direction of the winding axis P1 of the antenna conductors 3; 3k; 3m are magnetic bodies 6; 6a; 6c; 6d; 6f to 6h; Since it can be covered, the magnetic flux φ3 opposite to the magnetic flux φ1 passing outside the antenna conductor 3; 3k; 3m can be further reduced. As a result, it is possible to further suppress the reduction of the induced current induced in the antenna conductors 3; 3k; 3m.

  In the antenna device 1 according to the third aspect: 1g; 1h; 1k; 1m, in the second aspect, the magnetic body 6; 6g; 6h; 6k; 6m is the winding axis P1 of the antenna conductor 3; 3k; In the direction of P2; P3, located between the counterpart antenna conductor 94 and the antenna conductor 3; 3k; 3m; provided on the antenna conductor 3; 3k; 3m; and the antenna conductor 3; 3k; It is provided so as to overlap with all of the antenna conductors 3; 3k; 3m when viewed in the direction of the winding axis P1; P2; P3 of 3 m.

  In the antenna device 1; 1g; 1h; 1k; 1m according to the third aspect, the magnetic body 6; 6g is formed on the entire second main surface 22 located between the antenna conductor 3; 3k; 3m and the counterpart antenna conductor 94. 6h; 6k; 6m. Thereby, the magnetic flux φ3 passing through the antenna conductor 3; 3k; 3m opening 31; 31k; 31m can be further reduced, so that the induced current caused by the magnetic flux φ1 passing outside the antenna conductor 3; 3k; The causative magnetic flux φ3 can be further reduced. As a result, it is possible to further suppress the reduction of the induced current induced in the antenna conductors 3; 3k; 3m.

  In the antenna devices 1a to 1d according to the fourth aspect, in any one of the first to third aspects, the antenna conductor 3 has an opening 31 (first opening) inside the inner peripheral edge 32. The magnetic bodies 6a to 6d have an opening 61 (second opening). The opening 61 overlaps at least a part of the opening 31 when viewed in the direction of the winding axis P <b> 1 of the antenna conductor 3.

  In the antenna devices 1a to 1d according to the fourth aspect, the antenna conductor 3 has the opening 31 and the magnetic bodies 6a to 6d have the opening 61. Thereby, since the antenna conductor 3 and the central part of the magnetic bodies 6a to 6d can be penetrated in the direction of the winding axis P1 of the antenna conductor 3, for example, other components can be inserted into the opening 31 and the opening 61. , Can increase the degree of freedom of implementation.

  In the antenna device 1; 1e to 1h according to the fifth aspect, in any one of the first to third aspects, the antenna conductor 3; 3k; 3m has an opening 31 (first 1 opening). The magnetic bodies 6; 6e to 6h overlap with the opening 31 when viewed from the direction of the winding axis P1; P2; P3 of the antenna conductor 3; 3k;

  In the antenna device 1k according to the sixth aspect, in any one of the first to fifth aspects, the magnetic body 6k is formed in a curved surface shape.

  In the antenna device 1k according to the sixth aspect, the magnetic body 6k is formed in a curved surface shape. Thereby, the freedom degree of mounting of antenna device 1k can be raised. For example, the antenna device 1k can be attached to the curved surface of the casing 71.

  The antenna device 1 according to the seventh aspect: 1a to 1h; 1k; 1m further includes a booster antenna 8 in any one of the first to sixth aspects. The booster antenna 8 includes at least a coil conductor 81 (inductor), and is provided adjacent to the antenna conductor 3; 3k; 3m with respect to the winding axis P1, P2, P3 of the antenna conductor 3; 3k; 3m.

  In the antenna device 1; 1a to 1h; 1k; 1m according to the seventh aspect, a booster antenna 8 including an inductor (coil conductor 81) is provided adjacent to the antenna conductor 3; 3k; 3m. As a result, the booster antenna 8 is magnetically coupled to the antenna conductor 3; 3k; 3m, and the magnetic flux generated in the booster antenna 8 is linked to the antenna conductor 3; 3k; 3m, so that the current flowing through the antenna conductor 3; 3k; Can be bigger. Therefore, it is possible to improve the communication characteristics while reducing the size of the antenna device 1; 1a to 1h; 1k; 1m.

  In the antenna device 1 according to the eighth aspect 1; 1a to 1h; 1k; 1m, in the seventh aspect, the booster antenna 8 is seen in the direction of the winding axis P1; P2; P3 of the antenna conductor 3; 3k; The antenna conductors 3; 3k; 3m are provided so as not to overlap with each other and along the outer peripheral edges 33; 33m of the antenna conductors 3; 3k; 3m.

  In the antenna device 1 according to the ninth aspect; 1a to 1h; 1k; 1m, the antenna conductor 3; 3k; 3m is wound a plurality of times in any one of the first to eighth aspects.

  The electronic device 7 according to the tenth aspect; the wireless earphone 7k (electronic device) includes the antenna device 1 according to any one of the first to ninth aspects; 1a to 1h; 1k; 1m; The casing 71 accommodates the antenna device 1; 1a to 1h; 1k; 1m.

  In electronic device 7; wireless earphone 7k (electronic device) according to the tenth aspect, antenna device 1; 1a to 1h; 1k; 1m, antenna conductor 3; 3k; 3m winding axis P1; P2; The magnetic conductors 6; 6a to 6h; 6k; 6m are provided on the side of the antenna conductors 3; 3k; 3m facing the counterpart antenna conductor 94. Thus, when the antenna conductor 3; 3k; 3m and the counterpart antenna conductor 94 face each other so that the antenna conductor 3; 3k; 3m opening 31; 31k; 31m overlaps the counterpart opening 97 of the counterpart antenna conductor 94. In addition, the direction of the magnetic flux φ2 generated in the counterpart antenna conductor 94 can be changed by the magnetic bodies 6; 6a to 6h; 6k; 6m. As a result, it can be suppressed that the induced current caused by the magnetic flux φ1 passing outside the antenna conductor 3; 3k; 3m is canceled by the induced current caused by the magnetic flux φ3 passing through the antenna conductor 3; 3k; 3m opening 31; 31k; 31m. That is, it is possible to suppress a reduction in the induced current induced in the antenna conductors 3; 3k; 3m by the magnetic flux generated in the counterpart antenna conductor 94.

  The electronic device according to the eleventh aspect is an earphone in the tenth aspect. The antenna conductors 3; 3k; 3m are arranged on the housing 71 of the earphone or the circuit board 72 (substrate part) built in the housing 71.

  The present invention is not limited to the above-described embodiment, and various modifications can be made according to design or the like as long as the technical idea according to the present invention is not deviated.

1, 1a to 1h, 1k, 1m Antenna device 2, 2k Base material 21 First main surface 22 Second main surface 3, 3k, 3m Antenna conductor 31, 31k, 31m Opening (first opening)
32,32m Inner peripheral edge 33,33m Outer peripheral edge 6,6a-6h, 6k, 6m Magnetic body 61 Opening (second opening)
7 Electronic equipment 7k Wireless earphone (electronic equipment)
71 Case 72 Circuit board (board part)
8 Booster antenna 81 Coil conductor (inductor)
9 External equipment 94 Mating antenna conductor 97 Mating opening P1, P2, P3 Winding axis W1 Dimension W2 Width

Claims (11)

An antenna device that is used for wireless communication with an external device that is a communication partner and has a loop-like counterpart antenna conductor having a counterpart opening,
A looped antenna conductor;
With magnetic material,
The antenna conductor is wound at least once,
When viewed in the direction of the winding axis of the antenna conductor, the width between the outer peripheral edges of the antenna conductor in at least one direction is smaller than the width of the counterpart opening,
The magnetic body is located between the counterpart antenna conductor and the antenna conductor in the direction of the winding axis of the antenna conductor, is provided on the antenna conductor, and is wound around the antenna conductor. It is provided so as to overlap with at least the inner peripheral edge of the antenna conductor as viewed in the direction of the axis,
Antenna device. The magnetic body is located between the counterpart antenna conductor and the antenna conductor in the direction of the winding axis of the antenna conductor, is provided on the antenna conductor, and is wound around the antenna conductor. As viewed in the direction of the axis, it is provided so as to overlap with a region between the inner peripheral edge of the antenna conductor and the outer peripheral edge of the antenna conductor.
The antenna device according to claim 1. The magnetic body is located between the counterpart antenna conductor and the antenna conductor in the direction of the winding axis of the antenna conductor, is provided on the antenna conductor, and is wound around the antenna conductor. It is provided so as to overlap all of the antenna conductors in the axial direction.
The antenna device according to claim 2. The antenna conductor has a first opening inside the inner peripheral edge, and
The magnetic body has a second opening that overlaps at least a part of the first opening when viewed in the direction of the winding axis of the antenna conductor.
The antenna device according to any one of claims 1 to 3. The antenna conductor has a first opening inside the inner peripheral edge, and
The magnetic body overlaps the first opening when viewed in the direction of the winding axis of the antenna conductor.
The antenna device according to any one of claims 1 to 3. The magnetic body is formed in a curved surface shape,
The antenna device according to claim 1. A booster antenna that includes at least an inductor and is provided adjacent to the antenna conductor as viewed in the direction of the winding axis of the antenna conductor;
The antenna device according to claim 1. The booster antenna is provided along the outer peripheral edge of the antenna conductor so as not to overlap the antenna conductor as seen in the direction of the winding axis of the antenna conductor.
The antenna device according to claim 7. The antenna conductor is wound a plurality of times;
The antenna device according to claim 1. The antenna device according to any one of claims 1 to 9,
A housing for housing the antenna device;
Electronics. The electronic device is an earphone,
The antenna conductor is disposed on the housing of the earphone, or on a substrate portion built in the housing,
The electronic device according to claim 10.