JP6558106B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device, and more particularly to an antenna device comprising a combination of an HF band planar coil antenna and a UHF band high-frequency antenna suitable for NFC (Near Field Communication).

  In recent years, portable wireless devices such as smartphones have been implemented with various communication functions such as a telephone / data communication function, wireless LAN, Bluetooth (registered trademark), GPS, and NFC.

  On the other hand, in order to protect the built-in circuit from external noise and prevent unnecessary radiation of noise generated in the device, the mobile electronic device is provided with a metal shield. Recently, considering the reduction in thickness, weight, durability against impacts such as dropping, and design, the case of portable electronic devices has been changed from resin to metal, and the number of cases that also serve as a metal shield has increased. Yes. However, since a metal shield generally prevents radio waves, when an antenna is provided, it is necessary to provide it at a position that does not overlap with the metal shield. When the metal shield is provided over a wide range, the arrangement of the antenna becomes a problem.

  In order to solve the above problem, for example, the antenna device described in Patent Document 1 is an NFC antenna suitable for an RFID system, and includes a loop-shaped or spiral-shaped coil conductor, a conductor opening, and the conductor opening. It has a structure in which a conductor layer having connected slit portions and a magnetic sheet disposed farther from the coil conductor as viewed from the conductor layer are provided, and the coil opening portion overlaps the conductor opening portion in plan view. According to this antenna device, the current flows through the metal layer so as to block the magnetic field generated by the current flowing through the coil conductor, and the current flowing around the opening of the metal layer passes through the periphery of the slit due to the edge effect. Current also flows around the metal layer. As a result, a magnetic field is also generated from the metal layer, and the metal layer largely circulates the magnetic flux, so that the communication distance between the antenna device and the counterpart antenna can be extended.

  In addition, the antenna device described in Patent Document 2 includes a coil conductor and a planar conductor, and is disposed so that a conductor opening surface through which the winding axis of the coil conductor passes is opposed to the planar conductor. The coil conductor is partially overlapped with the edge of the outer periphery of the planar conductor in plan view from the winding axis direction. Therefore, it is possible to realize an antenna device with a small occupation area while ensuring a predetermined communication distance.

Japanese Patent No. 4941600 Japanese Patent No. 5234216

  As described above, when the casing of the portable electronic device also serves as a metal shield, it is necessary to provide an antenna at a position that does not overlap with the metal shield. When the metal shield is provided over a wide area, the antenna arrangement is a problem. It becomes. In particular, when both a planar coil antenna for NFC and a high-frequency antenna used for UHF band wireless communication are mounted, it is very difficult to efficiently lay out while ensuring desired antenna characteristics.

  Accordingly, an object of the present invention is to provide an antenna device capable of efficiently laying out both in a limited space in a casing of a portable wireless device while ensuring good antenna characteristics of a planar coil antenna and a high-frequency antenna. It is to be.

  In order to solve the above problems, an antenna device according to the present invention includes a planar coil antenna, a high-frequency antenna that overlaps a part of the planar coil antenna in a plan view, and another part of the planar coil antenna that overlaps in a plan view. And a magnetic sheet that does not overlap the high-frequency antenna in plan view.

  ADVANTAGE OF THE INVENTION According to this invention, both can be efficiently laid out in the limited space in the housing | casing of a portable radio | wireless apparatus, ensuring the desired antenna characteristic of a planar coil antenna and a high frequency antenna. In addition, it is possible to ensure the desired antenna characteristics of the high-frequency antenna by suppressing the influence of the magnetic sheet on the high-frequency antenna while securing the magnetic path of the magnetic flux interlinking with the planar coil antenna.

  In the present invention, it is preferable that the high-frequency antenna does not cover a coil axis of the planar coil antenna. The area of the region where the high-frequency antenna overlaps the inner diameter portion of the planar coil antenna is preferably less than 62.5% of the total area of the inner diameter portion of the planar coil antenna, more preferably 50% or less. Preferably, it is 12.5% or more and 50% or less. According to this configuration, it is possible to prevent deterioration of the characteristics of the planar coil antenna due to the influence of the high frequency antenna.

  In the present invention, the planar coil antenna is formed of a loop or spiral coil pattern, and the high-frequency antenna covers a part of the coil pattern and a part of an inner diameter part surrounded by the coil pattern. Is preferred. According to this configuration, the planar coil antenna can be efficiently laid out in a limited space within the casing that is widely covered with the high-frequency antenna while ensuring the desired antenna characteristics of the planar coil antenna.

  In the present invention, the planar coil antenna is provided in parallel with a first direction and a second direction orthogonal to the first direction, and the planar conductor is the first direction of the planar coil antenna. Extending from one end to the other end of the planar coil antenna to cover the one end of the planar coil antenna, and an edge of the planar conductor extends in the second direction and crosses the coil pattern. It is preferable that the other end portion of the coil antenna in the first direction is not covered with the planar conductor. According to this configuration, it is possible to efficiently lay out the planar coil antenna in a limited space in the casing that is widely covered with the planar conductor while ensuring good antenna characteristics.

  In the present invention, the planar coil antenna, the high-frequency antenna, and the magnetic sheet are accommodated in a casing of a portable wireless device, and at least a portion of the casing that covers the planar coil antenna and the high-frequency antenna is made of resin. Is preferred. According to this configuration, according to this configuration, the casing does not affect the characteristics of the planar coil antenna or the high-frequency antenna. Therefore, both can be efficiently laid out in a limited space in the housing while ensuring the desired antenna characteristics of the planar coil antenna and the high-frequency antenna.

  In the present invention, it is preferable that the planar coil antenna and the magnetic sheet are accommodated in a casing of a portable wireless device, and the high-frequency antenna is a part of the casing. According to this configuration, since it is not necessary to secure a mounting space for the high-frequency antenna in the housing, the degree of freedom in the layout of the planar coil antenna can be increased. In addition, since there is no member that affects the electromagnetic waves radiated from the high-frequency antenna outside the high-frequency antenna, the radiation characteristics of the high-frequency antenna can be improved.

  According to the present invention, there is provided an antenna device capable of efficiently laying out both in a limited space in a casing of a portable wireless device while ensuring good antenna characteristics of a planar coil antenna and a high-frequency antenna. Can do.

FIG. 1 is a schematic perspective view showing the configuration of a portable wireless device including an antenna device according to a first embodiment of the present invention. 2 is a plan view transparently showing the configuration of the antenna device 1 shown in FIG. 1. FIG. 2A shows a state in which the housing 50 (particularly the metal cover layer 51B) is present, and FIG. The state where is omitted is shown. 3 is a cross-sectional view of the antenna device along the line AA in FIG. FIG. 4 is a graph showing the relationship between the planar coil antenna and the covering area of the metal cover layer. FIG. 5 is a plan view transparently showing the configuration of the antenna device according to the second embodiment of the present invention, where (a) shows a case 50 (particularly a metal cover layer 51B), (b) Indicates a state in which the casing 50 is omitted. 6 is a cross-sectional view of the antenna device along the line AA in FIG. FIG. 7 is a schematic cross-sectional view showing the configuration of the antenna device according to the third embodiment of the present invention. FIG. 8 is a schematic cross-sectional view showing the configuration of the antenna device according to the fourth embodiment of the present invention. FIG. 9 is a schematic cross-sectional view showing the configuration of the antenna device according to the fifth embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing the configuration of the antenna device according to the sixth embodiment of the present invention. FIG. 11 is a schematic cross-sectional view showing the configuration of the antenna device according to the seventh embodiment of the present invention. FIG. 12 is a schematic plan view showing the configuration of the antenna device according to the eighth embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic perspective view showing the configuration of a portable wireless device including an antenna device according to a first embodiment of the present invention.

  As shown in FIG. 1, the portable wireless device 100 according to the present embodiment is a smartphone, for example, and has a very thin housing 50. In the illustrated portable wireless device 100, the back surface 50b of the housing 50 is in an upward state, and the front surface 50a of the housing 50 in which a display is mainly provided faces downward. The housing 50 is made of a combination of resin and metal, and a metal cover layer 51B is provided in a wide range including the central portion of the back surface 50b of the housing 50. A resin cover layer 51A is provided on one end (upper end 50c) and the other end (lower end 50d) in the longitudinal direction (Y direction) of the back surface 50b of the housing 50, and a metal cover layer 51B. This is a non-shielded area where no is provided. The metal cover layer 51B is provided to improve the mechanical strength, magnetic shield characteristics, design, etc. of the housing.

  The portable wireless device 100 has a built-in antenna device 1, and the antenna device 1 is disposed on the upper end portion 50 c of the housing 50. The antenna device 1 includes a planar coil antenna 10 used for HF band wireless communication and a high-frequency antenna 20 used for UHF band wireless communication. The planar coil antenna 10 is an NFC antenna, for example, and its resonance frequency is 13.56 MHz. Since these antenna elements are provided at the upper end portion 50c of the casing 50 that is not covered with the metal cover layer 51B, wireless communication is possible.

  2 is a plan view transparently showing the configuration of the antenna device 1 shown in FIG. 1. FIG. 2A shows a state in which the housing 50 (particularly the metal cover layer 51B) is present, and FIG. The state where is omitted is shown. FIG. 3 is a cross-sectional view of the antenna device 1 taken along the line AA in FIG.

  As shown in FIGS. 2 (a), 2 (b), and 3, the antenna device 1 includes a planar coil antenna 10 and a high-frequency wave disposed so as to overlap with a part of the planar coil antenna 10 on the left side in the drawing. The antenna 20 includes a magnetic sheet 30 that is arranged so as to overlap with a part of the right side of the planar coil antenna 10 in a plan view and not overlap with the high-frequency antenna 20 in a plan view. A part of the planar coil antenna 10 that overlaps the high frequency antenna 20 does not overlap the magnetic sheet 30, and a part of the planar coil antenna 10 that overlaps the magnetic sheet 30 does not overlap the high frequency antenna 20.

  As shown in FIG. 3, the planar coil antenna 10, the high-frequency antenna 20, and the magnetic sheet 30 are accommodated in a housing 50, and the resin cover layer 51 </ b> A and the metal cover layer 51 </ b> B constituting the housing 50 are planar coil antennas. 10 is arranged on one main surface 10a side. On the other hand, the high frequency antenna 20 and the magnetic sheet 30 are disposed on the other main surface 10 b side of the planar coil antenna 10. Similar to the magnetic sheet 30, the metal cover layer 51 </ b> B is disposed so as to overlap with a part on the right side of the planar coil antenna 10 in the plan view and not overlap with the high frequency antenna 20 in the plan view.

  The planar coil antenna 10 includes a spiral pattern 10c formed on one main surface 11a of the flexible substrate 11, and is provided in parallel with the XY plane in this embodiment. In order to facilitate the antenna design and increase the area of the inner diameter portion 10d surrounded by the spiral pattern 10c as much as possible, the spiral pattern 10c is a rectangular spiral, and a linear pattern component extending in the X direction and a linear pattern component extending in the Y direction. Are preferably included. The external size of the planar coil antenna 10 is, for example, 30 × 40 (mm).

  In the present embodiment, both ends of the spiral pattern 10c are drawn to the vicinity of the edge of the flexible substrate 11, and in particular, the inner peripheral end of the spiral pattern 10c is drawn to the outside across the spiral pattern 10c. Both ends of the spiral pattern 10c are connected to, for example, an NFC chip mounted on the flexible substrate 11 or a main circuit board of a portable wireless device.

  The flexible substrate 11 is made of, for example, PET resin, and the plane size is appropriately set according to the size of the spiral pattern 10c. The thickness of the flexible substrate 11 is, for example, 30 μm. The flexible substrate 11 is provided in the housing 50 such that one main surface 11a, which is a surface on which the spiral pattern 10c is formed, faces the outside of the housing 50.

  The high-frequency antenna 20 is formed of a rectangular planar conductor (solid pattern), and a power supply line 21 is connected to the back surface thereof. The high-frequency antenna 20 is provided so as to overlap a part of the planar coil antenna 10 and covers a part of the spiral pattern 10c of the planar coil antenna 10 and a part of the inner diameter part 10d surrounded by the spiral pattern 10c. . The high-frequency antenna 20 may be a metal flat plate or a metal sheet, or may be a metal foil formed on the surface of the support substrate.

  In the present embodiment, the metal cover layer 51 </ b> B is a part of the housing 50 and covers the planar coil antenna 10 accommodated in the housing 50, but does not cover the high-frequency antenna 20. The high frequency antenna 20 overlaps with the resin cover layer 51 </ b> A of the housing 50 in plan view.

  In the present embodiment, the magnetic sheet 30 is disposed on the inner side of the housing 50 with respect to the planar coil antenna 10, and is particularly attached to the other main surface 11 b of the flexible substrate 11. The thickness of the magnetic sheet 30 is not particularly limited as long as it can fulfill its role. The planar coil antenna 10 is often mounted close to the battery pack 40 of the portable wireless device as shown in the figure, but when the magnetic sheet 30 is interposed between the battery pack 40 and the planar coil antenna 10. Can secure the magnetic path of the magnetic flux generated by the current flowing through the planar coil antenna 10. Therefore, the influence which the metal body which comprises the battery pack 40 has on the planar coil antenna 10 can be suppressed, and desired antenna characteristics can be obtained.

  The magnetic sheet 30 is preferably a composite magnetic sheet in which a flat magnetic metal powder having a large aspect ratio is combined with a polymer. The flat metal powder overlaps with the thickness direction of the composite magnetic sheet, and the surface direction is oriented so as to be parallel to the surface direction of the composite magnetic sheet, so that the effective magnetic permeability in the surface direction of the composite magnetic sheet is increased. Can do. According to this, the magnetic field generated by the planar coil antenna 10 can be drawn from the outside into the magnetic sheet 30 and guided in the horizontal direction perpendicular to the coil axis. Further, the flat magnetic powder is densely arranged in the polymer. However, since the flat magnetic powder is insulated by the polymer, generation of eddy current can be prevented. Therefore, both high magnetic permeability and low magnetic loss can be realized in the use frequency band (for example, 13.56 MHz) of the planar coil antenna 10.

The high-frequency antenna 20 extends substantially parallel to the planar coil antenna 10 from one end portion (left end portion in the figure) of the planar coil antenna 10 toward the other end portion (right end portion in the figure). A part of 20 covers one end of the planar coil antenna 10 in the Y direction. Specifically, the high frequency antenna 20 covers one end portion of the spiral pattern 10c in the Y direction and a part of the inner diameter portion 10d surrounded by the spiral pattern 10c. One end of the high frequency antenna 20 in the Y direction does not overlap the planar coil antenna 10, and the other end of the high frequency antenna 20 in the Y direction is closer to one end in the Y direction than the coil axis Z ₀ of the planar coil antenna 10. positioned. As shown in FIG. 2, the width W ₂ in the X direction of the high frequency antenna 20 is wider than the width W _{1 in} the X direction of the planar coil antenna 10, so that the high frequency antenna 20 covers the entire X direction of the planar coil antenna 10. However, a part of the X direction may be covered as shown in FIG. The size of the high-frequency antenna 20 can be appropriately set according to the resonance frequency.

  Since the high-frequency antenna 20 is disposed on the other main surface 10b side of the planar coil antenna 10, the characteristics of the planar coil antenna 10 are not greatly deteriorated by the influence of the high-frequency antenna 20. Further, since the planar coil antenna 10 has a spiral pattern and does not cover the high frequency antenna 20 in a wide range, the influence of the planar coil antenna 10 on the high frequency antenna 20 is small, and thus the high frequency antenna 20 overlaps the planar coil antenna 10. It works without any problems.

  The metal cover layer 51B extends from the other end portion (right end portion in the drawing) in the Y direction of the planar coil antenna 10 toward one end portion (left end portion in the drawing), and part of the metal cover layer 51B is flat. The other end of the coil antenna 10 in the Y direction is covered. Specifically, the metal cover layer 51B covers the other end portion in the Y direction of the spiral pattern 10c of the planar coil antenna 10 and a part of the inner diameter portion 10d surrounded by the spiral pattern 10c.

One end portion of the Y direction of the metal cover layer 51B overlapping with the planar coil antenna 10 is preferably located on the other end side in the Y direction than the coil axis Z ₀ without covering the coil axis Z ₀ of the planar coil antenna 10 . Further, as shown in FIG. 2, the region where the metal cover layer 51B overlap at the inner diameter portion 10d in plan view of the planar coil antenna 10 is a rectangular area, the total area of the area S ₁ has an inner diameter portion 10d of the planar coil antenna 10 It is preferably less than 62.5% of S ₀ , more preferably 50% or less, and particularly preferably 12.5% or more and 50% or less. In other words, the exposed area of the inner diameter portion 10d of the planar coil antenna 10 that is not covered with the metal cover layer 51B is preferably 37.5% or more of the total area of the inner diameter portion 10d of the planar coil antenna 10, and is 50%. More preferably, it is more than 50% and less than 87.5%. Here, the inner diameter portion 10d of the planar coil antenna 10 refers to a region inside the innermost periphery of the spiral pattern 10c. Further, in a region overlapping the inner diameter portion 10d of the planar coil antenna 10 in plan view, the entire surface of the metal cover layer 51B is made of metal, and there are no portions from which metal such as openings and slits are excluded.

  FIG. 4 is a graph showing the relationship between the coverage area of the planar conductor (corresponding to the metal cover layer 51B) covering the planar coil antenna 10 and the communication distance of the planar coil antenna 10, and the lower horizontal axis represents the planar coil antenna. The ratio of the covering area of the planar conductor to the entire area of the inner diameter portion (covering ratio) (%), and the upper horizontal axis is the ratio of the covering area of the planar conductor to the entire area of the inner diameter portion 10d of the planar coil antenna 10 (covering ratio) ( %), The vertical axis represents the maximum communication distance (mm) in the so-called card mode of the planar coil antenna. The formation region of the planar coil antenna 10 refers to a region inside the outermost periphery of the spiral pattern 10c, and includes not only the region where the spiral pattern 10c is actually formed, but also the space between the adjacent spiral patterns 10c and the inner diameter portion. 10d. Further, the maximum communication distance in the card mode of the planar coil antenna means that a test signal is transmitted from the test reader / writer, the planar coil antenna 10 receives the test signal and transmits the modulation signal, and the modulation signal is transmitted to the search coil. The maximum value of the distance from the planar coil antenna 10 to the reader / writer when the voltage level of the received signal satisfies the threshold level. The planar coil antenna 10 has an outer size of 40 mm × 50 mm and a turn number of 3 turns.

  As shown in FIG. 4, the communication distance of the planar coil antenna 10 is about 40 mm when the coverage of the formation area of the planar coil antenna 10 is 0%, and the coverage of the formation area of the planar coil antenna 10 is 10%. Sometimes the maximum is about 48 mm. Thereafter, the reduction in the communication distance of the planar coil antenna 10 is gentle until the coverage reaches 50%, and the communication distance when the coverage is 50% is about 44 mm. However, when the coverage ratio exceeds 50%, the reduction rate of the communication distance increases, and when the coverage ratio is 60%, the communication distance becomes 40 mm, which decreases to the same level as when the coverage ratio is 0%. Further, the communication distance when the coverage is 80% is about 28 mm.

  Here, the relationship between the coverage of the formation area of the planar coil antenna 10 and the coverage of the inner diameter portion 10d of the planar coil antenna 10 is as follows. First, when the coverage of the formation area of the planar coil antenna 10 is less than 10%, the coverage of the inner diameter portion 10d of the planar coil antenna 10 is 0%. Thereafter, the coverage of the inner diameter portion 10d of the planar coil antenna 10 increases with the increase of the coverage of the formation region of the planar coil antenna 10, and the coverage of the formation region of the planar coil antenna 10 is 40%, 50%, and The coverage of the inner diameter portion 10d of the planar coil antenna 10 when it is 60% is 37.5%, 50%, and 62.5%, respectively. Furthermore, when the coverage of the formation area of the planar coil antenna 10 is 90%, the coverage of the inner diameter portion 10d of the planar coil antenna 10 is 100%.

From the above results, the area _{S 1} of a region where the metal cover layer 51B overlap at the inner diameter portion 10d in plan view of the planar coil antenna 10 is less than 62.5% of the total area _{S 0} of the inner diameter portion 10d of the planar coil antenna 10 It is preferable that it is preferably 50% or less in consideration of the margin, and more preferably 12.5% or more and 50% or less. According to this configuration, the influence of the metal cover layer 51 </ b> B on the planar coil antenna 10 can be suppressed, the communication distance of the planar coil antenna 10 can be extended, and both securing of antenna characteristics and space saving can be achieved.

  Similarly to the metal cover layer 51B, the magnetic sheet 30 extends from the other end portion (right end portion in the drawing) in the Y direction of the planar coil antenna 10 toward one end portion (left end portion in the drawing). Is overlapped with the other end portion of the planar coil antenna 10 in the Y direction. In order to sufficiently secure the magnetic path of the magnetic flux interlinking with the planar coil antenna 10, it is preferable to provide the magnetic sheet 30 so as to overlap the entire planar coil antenna 10, but the high frequency antenna 20 is close to the magnetic sheet 30. Then, the characteristics of the high frequency antenna 20 are deteriorated. Therefore, the magnetic sheet 30 is provided in a region that does not overlap the high frequency antenna 20.

  One end of the magnetic sheet 30 overlapping the planar coil antenna 10 in the Y direction is preferably provided so as not to protrude outside the metal cover layer 51B as shown in the figure. That is, the position of the one end portion in the Y direction of the magnetic sheet 30 is preferably located on the other end side in the Y direction with respect to the position of the one end portion of the metal cover layer 51B. Thus, by disposing the magnetic sheet 30 farther than the metal cover layer 51B when viewed from the high frequency antenna 20, the influence of the magnetic sheet 30 on the high frequency antenna 20 can be minimized, and the high frequency antenna 20 Desired antenna characteristics can be ensured.

  Note that the other end portion in the Y direction and the both end portions in the X direction of the magnetic sheet 30 may protrude outside the flexible substrate 11 as shown in the figure, and are not inside the flexible substrate 11 and are accommodated inside. Also good. Moreover, the magnetic sheet 30 may be affixed on the back surface of the flexible substrate 11 as illustrated, or may be provided apart from the flexible substrate 11.

  As shown in FIG. 1, the area where the metal cover layer 51B is not provided in the back surface 50b of the housing 50, that is, the space in which the antenna in the housing 50 can be mounted is very limited. It is difficult to mount the planar coil antenna 10 and the high-frequency antenna 20 in a limited space so that they do not overlap each other and do not overlap with the metal cover layer 51B at all. On the other hand, it has been considered that the planar coil antenna 10 and the high-frequency antenna 20 must be arranged so as not to overlap each other. However, by providing a part of the planar coil antenna 10 so as to overlap with the metal cover layer 51B and further providing a high-frequency antenna 20 so as to overlap with a part of the planar coil antenna 10, both in a space not covered by the metal cover layer 51B. It is possible to efficiently layout the antennas.

  On the other hand, in order to stably operate the planar coil antenna 10, it is necessary to provide the magnetic sheet 30 on the other main surface 10 b side of the planar coil antenna 10, and when this overlaps with the high frequency antenna 20, the radiation of the high frequency antenna 20 is performed. Characteristics deteriorate. However, in this embodiment, since the magnetic sheet 30 is provided so as to overlap the planar coil antenna 10 in plan view and not to overlap the high frequency antenna 20, both the planar coil antenna 10 and the high frequency antenna 20 can be operated stably. Can do.

  As described above, the antenna device 1 according to the present embodiment includes the planar coil antenna 10 for short-range wireless communication and the high-frequency antenna 20 so that the high-frequency antenna 20 overlaps a part of the planar coil antenna in plan view. Therefore, the two antennas can be efficiently laid out in a limited space in the casing 50 of the portable wireless device 100 while ensuring the desired antenna characteristics of the planar coil antenna 10 and the high-frequency antenna 20. Further, since the magnetic sheet 30 is provided so as to overlap a part of the planar coil antenna 10 in plan view, the desired antenna characteristics of the planar coil antenna 10 are ensured without being affected by a metal body such as a battery pack. be able to. Further, since the magnetic sheet 30 is provided so as not to overlap with the high frequency antenna 20 in plan view, it is possible to prevent the characteristics of the high frequency antenna 20 from being deteriorated and to ensure good communication of the high frequency antenna 20. .

  FIG. 5 is a plan view transparently showing the configuration of the antenna device according to the second embodiment of the present invention, where (a) shows a case 50 (particularly a metal cover layer 51B), (b) Indicates a state in which the casing 50 is omitted. FIG. 6 is a cross-sectional view of the antenna device along the line AA in FIG.

  As shown in FIGS. 5A, 5 </ b> B, and 6, the antenna device 2 is characterized in that the high-frequency antenna 20 is disposed on one main surface 10 a side of the planar coil antenna 10. Other configurations are the same as those of the first embodiment.

  When the high-frequency antenna 20 is provided on the one main surface 10a side of the planar coil antenna 10, the outside of the planar coil antenna 10 is covered with the high-frequency antenna 20, so that the shielding effect by the high-frequency antenna 20 becomes a problem. . In other words, the planar conductor constituting the high-frequency antenna 20 shields radio waves radiated from the planar coil antenna 10, so that the planar coil antenna 10 cannot be operated correctly in some cases. The same applies not only to the case where the single unit of the high-frequency antenna 20 covers the planar coil antenna 10 widely but also to the case where the combination of the high-frequency antenna 20 and the metal cover layer 51B covers the planar coil antenna 10 widely. It is considered that the outside of the casing 50 cannot be sufficiently radiated, and as a result, the radiation efficiency of the planar coil antenna 10 is significantly reduced.

In order to solve such a problem, a slit region SL having a constant width is formed between the high-frequency antenna 20 and the metal cover layer 51B when viewed from the Z-axis direction orthogonal to the XY plane. The slit region SL is a linear unshielded region extending in the X direction, and its width W ₃ is preferably 1/10 or more of the width W ₄ of the inner diameter portion 10d of the planar coil antenna 10 in the same direction. / 5 or more is more preferable. Since the slit region SL serves as a magnetic path of magnetic flux interlinking with the planar coil antenna 10, the planar coil antenna 10 can be operated correctly.

The other end portion in the Y direction of the high-frequency antenna 20 that overlaps the planar coil antenna 10 is positioned on one end side in the Y direction with respect to the coil axis Z ₀ without overlapping with the coil axis Z ₀ of the planar coil antenna 10 in plan view. Is preferred. Further, as shown in FIG. 5, the region where the inner diameter portion 10d and the region overlapping in a plan view area of S ₂ and the metal cover layer 51B of the high frequency antenna 20 is planar coil antenna 10 overlaps with the inner diameter portion 10d in plan view of the planar coil antenna 10 sum of the areas _{S 1} of is preferably less than 62.5% of the total area _{S 0} of the inner diameter portion 10d of the planar coil antenna 10, and more preferably 50% or less, or more 12.5% 50 % Or less is particularly preferable. According to this configuration, it is possible to extend the communication distance of the planar coil antenna 10 by suppressing the adverse effects of the high-frequency antenna 20 and the metal cover layer 51B on the planar coil antenna 10, and it is possible to achieve both securing of antenna characteristics and space saving. It becomes possible.

  Furthermore, in the present embodiment, since the slit region SL that overlaps the inner diameter portion of the planar coil antenna 10 in plan view is provided, desired radiation characteristics of the planar coil antenna 10 can be ensured. Part of the magnetic flux that has passed through the inner diameter portion 10d of the planar coil antenna 10 and further passed through the slit region SL circulates greatly around the outside of the high-frequency antenna 20 and the outer side of the metal cover layer 51B to the inner diameter portion 10d of the planar coil antenna 10. Since it returns, the communication distance of the planar coil antenna 10 can be extended. Therefore, even when a small planar coil antenna is used, desired antenna characteristics necessary for short-range wireless communication can be ensured.

  As described above, the antenna device 2 according to the present embodiment can achieve the same effects as those of the first embodiment. In addition, since there is no member that affects the electromagnetic waves radiated from the high frequency antenna 20 outside the high frequency antenna 20, the radiation characteristics of the high frequency antenna 20 can be improved.

  FIG. 7 is a schematic cross-sectional view showing the configuration of the antenna device according to the third embodiment of the present invention.

  As shown in FIG. 7, the feature of the antenna device 3 is that the high-frequency antenna 20 constitutes a part of the casing 50 of the portable wireless device. That is, in the present embodiment, a part of the metal cover layer 51 </ b> B constituting the housing 50 is used as the high frequency antenna 20. Other configurations are the same as those of the second embodiment. According to the present embodiment, in addition to the effects of the invention according to the second embodiment, it is not necessary to secure a mounting space for the high-frequency antenna 20 in the housing 50, and the degree of freedom in layout of the planar coil antenna 10 is increased. be able to. Further, since there is no member that affects the electromagnetic waves radiated from the high frequency antenna 20 outside the high frequency antenna 20, the radiation characteristics of the high frequency antenna 20 can be improved.

  Next, an embodiment of the antenna device using the housing 50 without the metal cover layer 51B will be described in detail with reference to FIGS.

  FIG. 8 is a schematic cross-sectional view showing the configuration of the antenna device according to the fourth embodiment of the present invention.

  As shown in FIG. 8, the antenna device 4 is characterized in that the metal cover layer 51B is not provided in the housing 50 in the configuration of the antenna device 1 according to the first embodiment described above, and the resin cover layer 51A is provided. It is in that it is composed only of. Other configurations are the same as those of the first embodiment.

  The antenna device 4 according to the present embodiment includes the planar coil antenna 10 and the high-frequency antenna 20 for near field communication, and the high-frequency antenna 20 is provided so as to overlap with a part of the planar coil antenna 10 in plan view. In addition, while ensuring the desired antenna characteristics of the planar coil antenna 10 and the high-frequency antenna 20, both can be efficiently laid out in a limited space in the casing 50 of the portable wireless device 100. Further, since the magnetic sheet 30 is provided so as to overlap a part of the planar coil antenna 10 in plan view, the desired antenna characteristics of the planar coil antenna 10 are ensured without being affected by a metal body such as a battery pack. be able to. Further, since the magnetic sheet 30 is provided so as not to overlap with the high frequency antenna 20 in plan view, it is possible to prevent the characteristics of the high frequency antenna 20 from being deteriorated and to ensure good communication of the high frequency antenna 20. .

  FIG. 9 is a schematic cross-sectional view showing the configuration of the antenna device according to the fifth embodiment of the present invention.

  As shown in FIG. 9, the antenna device 5 is characterized in that the metal cover layer 51B is not provided in the housing 50 in the configuration of the antenna device 2 according to the second embodiment described above, and the resin cover layer 51A is provided. It is in that it is composed only of. Other configurations are the same as those of the second embodiment.

The other end portion in the Y direction of the high-frequency antenna 20 that overlaps the planar coil antenna 10 is preferably positioned on one end side in the Y direction with respect to the coil axis Z ₀ without covering the coil axis Z ₀ of the planar coil antenna 10. Further, the area S ₂ (see FIG. 5) of the region where the high-frequency antenna 20 overlaps with the inner diameter part 10d of the planar coil antenna 10 in plan view is less than 62.5% of the total area S ₀ of the inner diameter part 10d of the planar coil antenna 10. It is preferably 50% or less, more preferably 12.5% or more and 50% or less. According to this configuration, the adverse effect of the high-frequency antenna 20 on the planar coil antenna 10 can be suppressed, the communication distance of the planar coil antenna 10 can be extended, and both securing of antenna characteristics and space saving can be achieved.

  As described above, the antenna device 5 according to the present embodiment can achieve the same effects as those of the fourth embodiment. Further, since there is no member that affects the radio wave radiated from the high frequency antenna 20 outside the high frequency antenna 20, the radiation characteristics of the high frequency antenna 20 can be improved.

  FIG. 10 is a schematic cross-sectional view showing the configuration of the antenna device according to the sixth embodiment of the present invention.

  As shown in FIG. 10, the feature of the antenna device 6 is that, in the configuration of the antenna device 3 according to the third embodiment described above, the metal cover layer 51B is not provided in the housing 50, and the resin cover layer 51A is provided. It is in that it is composed only of. Other configurations are the same as those of the third embodiment. The antenna device 6 having such a configuration can achieve the same effects as those of the third embodiment. Further, since there is no member that affects the electromagnetic waves radiated from the high frequency antenna 20 outside the high frequency antenna 20, the radiation characteristics of the high frequency antenna 20 can be improved.

  FIG. 11 is a schematic cross-sectional view showing the configuration of the antenna device according to the seventh embodiment of the present invention.

  As shown in FIG. 11, the feature of the antenna device 7 is that, in the configuration of the antenna device 1 according to the above-described first embodiment, the housing 50 is configured only by the resin cover layer 51A, and the resin cover layer 51A. The metal film 53 is formed on the inner surface. The antenna device 7 having such a configuration can achieve the same effects as those of the first embodiment.

  FIG. 12 is a schematic plan view showing the configuration of the antenna device according to the eighth embodiment of the present invention, in particular, a diagram showing a modified example of the layout of the high-frequency antenna 20.

  As shown in FIG. 12, the antenna device 8 is characterized in that the high-frequency antenna 20 is offset in the X direction with respect to the planar coil antenna 10. For this reason, the high-frequency antenna 20 overlaps a part of the planar coil antenna 10 rather than the entire X direction. As described above, the center position in the X direction of the high-frequency antenna 20 is not necessarily aligned with the planar coil antenna 10. The antenna device 8 according to the present embodiment can also achieve the same effects as those of the first embodiment.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in each of the above embodiments, the planar coil antenna 10 is configured with a spiral pattern of several turns, but may be a loop pattern of less than one turn. In other words, the planar coil antenna 10 may be a loop or spiral planar coil pattern. In the case of a loop pattern of less than 1 turn, the number of turns is preferably 3/4 or more, and a circle defined by the diameter of the loop can be used as the inner diameter portion of the planar coil antenna 10.

  Moreover, in the said embodiment, although the smart phone was mentioned as a portable radio | wireless apparatus with which the antenna apparatus 1 is incorporated, the kind of portable radio | wireless apparatus is not specifically limited, It is a tablet terminal, a notebook PC, a wristwatch type wearable terminal, etc. Also good.

1-8 Antenna device 10 Planar coil antenna 10a One main surface (upper surface) of the planar coil antenna
10b The other main surface (back surface) of the planar coil antenna
10c spiral pattern 10d inner diameter part 11 flexible substrate 11a one main surface (upper surface) of flexible substrate
11b The other main surface (back surface) of the flexible substrate
20 High-frequency antenna 21 Feed line 30 Magnetic sheet 40 Battery pack 50 Case 50a Case front 50b Case back 50c One end (upper end) of the case in the longitudinal direction
50d The other end of the casing in the longitudinal direction (lower end)
51A Resin cover layer 51B Metal cover layer 53 Metal film 100 Portable radio equipment S ₀ Total area S of the inner diameter part of the planar coil antenna S ₁ Area of the area where the metal cover layer overlaps the inner diameter part of the planar coil antenna S _{2 The} high frequency antenna is a planar coil Area SL overlapping area of inner diameter of antenna Slit area W ₁ Width of planar coil antenna in X direction W ₂ Width of high frequency antenna in X direction W ₃ Width of slit area W ₄ Width of inner diameter of antenna coil Z ₀ Coil axis

Claims (7)

A planar coil antenna;
A high-frequency antenna comprising a planar conductor overlapping with a portion of the planar coil antenna in plan view;
An antenna device comprising: a magnetic sheet that overlaps with another part of the planar coil antenna in plan view and does not overlap with the high-frequency antenna in plan view.   The antenna device according to claim 1, wherein the high-frequency antenna does not cover a coil axis of the planar coil antenna.   The antenna device according to claim 1 or 2, wherein an area of a region where the high-frequency antenna overlaps with an inner diameter portion of the planar coil antenna is less than 62.5% of a total area of the inner diameter portion.   The antenna device according to claim 3, wherein an area of a region where the high-frequency antenna overlaps with an inner diameter portion of the planar coil antenna is 12.5% or more and 50% or less of a total area of the inner diameter portion. The planar coil antenna comprises a loop pattern or a spiral coil pattern,
5. The antenna device according to claim 1, wherein the high-frequency antenna covers a part of the coil pattern and a part of an inner diameter portion surrounded by the coil pattern. The planar coil antenna, the high-frequency antenna, and the magnetic sheet are accommodated in a casing of a portable wireless device,
The antenna device according to any one of claims 1 to 5, wherein at least a portion covering the planar coil antenna and the high-frequency antenna of the housing is made of resin. The planar coil antenna and the magnetic sheet are housed in a casing of a portable wireless device,
The antenna device according to claim 1, wherein the high-frequency antenna is a part of the housing.