JP2017204776A - Antenna device and portable wireless equipment comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a communication distance of an antenna device.SOLUTION: An antenna device comprises: a first metal layer 101 that has first and second regions 111 and 112; a coil pattern 10A that has first and second terminals 13 and 14; a first wiring pattern P1 connected between the first region 111 of the first metal layer 101 and the first terminal 13 of the coil pattern 10A; and a second wiring pattern P2 connected between the second region 112 of the first metal layer 101 and the second terminal 14 of the coil pattern 10A. At least a part of a loop antenna 10L is formed by the first metal layer 101, the first wiring pattern P1, and the second wiring pattern P2. Due to this invention, since the antenna device is configured by the coil pattern and the loop antenna, a communication distance can be increased compared with a case where the antenna device is configured only by the loop antenna.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an antenna device and a portable wireless device including the antenna device, and more particularly to an antenna device suitable for near field communication and a portable wireless device including the antenna device.

  In recent years, RFID (Radio Frequency Identification) systems are installed in portable wireless devices such as smartphones, and antenna devices for short-distance wireless communication with readers / writers, etc. are installed as communication means. Has been. As this type of antenna device, for example, the antenna device described in Patent Document 1 is known.

  The antenna device described in Patent Document 1 configures a loop antenna by connecting both ends of a radiation conductor to a ground pattern.

Japanese Patent No. 57089797

  However, the antenna device described in Patent Document 1 has a problem that the communication distance is insufficient because only one loop antenna is configured by the radiation conductor and the ground pattern.

  Therefore, an object of the present invention is to provide an antenna device with a further increased communication distance and a portable wireless device including the antenna device.

  An antenna device according to the present invention includes a first metal layer having first and second regions, a coil pattern having first and second terminals, the first region of the first metal layer, and the first region. Connected between the first wiring pattern connected between the first terminal of the coil pattern and the second region of the first metal layer and the second terminal of the coil pattern. And a second wiring pattern, wherein at least a part of a loop antenna is formed by the first metal layer, the first wiring pattern, and the second wiring pattern.

  A portable wireless device according to the present invention includes the antenna device described above.

  According to the present invention, since the coil pattern and the loop antenna are connected in series, the communication distance can be increased as compared with the case where only the loop antenna is formed. The coil pattern may include a solenoid coil formed by winding a conductor around a plate-shaped magnetic member, or may include a meander-shaped conductor. When using a meander-shaped conductor, it is preferable that the coil pattern further includes a wavy magnetic member, and the upper and lower positions of the magnetic member and the conductor are alternately switched between adjacent conductors.

  In the present invention, the coil pattern preferably does not overlap the first metal layer in plan view. This makes it possible to further increase the size of the inner diameter portion of the loop antenna.

  The antenna device according to the present invention preferably further comprises a first transmission / reception circuit connected to the first or second wiring pattern, and a frequency band of a signal transmitted / received connected to the first metal layer is It is more preferable to further include a second transmission / reception circuit different from the first transmission / reception circuit. According to this, the first metal layer not only constitutes a part of the loop antenna, but also functions as a radiation conductor of another antenna. In this case, it is preferable to further include an inductance element inserted into the first or second wiring pattern. According to this, it becomes possible to isolate | separate the signal component of two antennas.

  The antenna device according to the present invention further includes a circuit board parallel to the first metal layer, and the first wiring pattern is perpendicular to the first wiring formed on the circuit board and the circuit board. And a first connection pin that connects one end of the first wiring and the first region of the first metal layer, and the second wiring pattern is formed on the circuit board. Preferably, the second wiring includes a second connection pin that is perpendicular to the circuit board and connects one end of the second wiring to the second region of the first metal layer. . According to this, since the loop antenna has a three-dimensional shape, it is possible to capture the horizontal magnetic flux.

  In this case, the first wiring pattern is perpendicular to the circuit board, and further includes a third connection pin that connects the other end of the first wiring and the first terminal of the coil pattern. The second wiring pattern further includes a fourth connection pin that is perpendicular to the circuit board and connects the other end of the second wiring and the second terminal of the coil pattern. It is preferable. According to this, the loop antenna has a more three-dimensional shape.

  The antenna device according to the present invention preferably further includes a second metal layer facing the first metal layer through a slit and constituting the same plane as the first metal layer. In this case, it is preferable that at least a part of the coil pattern overlaps the second metal layer in plan view. In such a configuration, the second metal layer serves as an electromagnetic shield and the antenna characteristics are deteriorated. However, in the present invention, even with such a configuration, communication can be performed correctly.

  In the present invention, the first region of the first metal layer and the first terminal of the coil pattern are connected via at least the first wiring pattern and the second metal layer, At least a part of the loop antenna may be formed by the first metal layer, the second metal layer, the first wiring pattern, and the second wiring pattern. According to this, the size of the inner diameter portion of the loop antenna can be further increased, and the degree of freedom in design increases.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the antenna apparatus with which communication distance was expanded more, and a portable radio apparatus provided with the same.

FIG. 1 is a schematic perspective view showing an appearance of a portable wireless device 100 including an antenna device according to the first embodiment of the present invention. FIG. 2 is a plan view of the back surface of the portable wireless device 100 as viewed from the inside. FIG. 3 is a perspective view showing the appearance of the solenoid coil 10A. FIG. 4 is a plan view showing the appearance of the meander coil 10B. FIG. 5 is a diagram in which the magnetic member 11 is omitted from the meander coil 10B. FIG. 6 is a schematic diagram for explaining the direction of the magnetic flux generated by the solenoid coil 10A. FIG. 7 is a schematic diagram for explaining the direction of magnetic flux generated by the meander coil 10B. FIG. 8 is a partial cross-sectional view of the portable wireless device 100. FIG. 9 is a schematic perspective view for explaining the configuration of the antenna device according to the first embodiment of the present invention. FIG. 10 is a schematic diagram showing a magnetic flux generated from an external reader / writer. FIG. 11 is a schematic perspective view for explaining the configuration of the antenna device according to the second embodiment of the present invention.

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

<First Embodiment>
FIG. 1 is a schematic perspective view showing an appearance of a portable wireless device 100 including an antenna device according to the first embodiment of the present invention.

  A portable wireless device 100 illustrated in FIG. 1 is a smartphone, for example, and is configured by a thin box-shaped housing. FIG. 1 is a view of the portable wireless device 100 as viewed from the back side, and the front surface on which a display or the like is provided faces downward. The casing of the portable wireless device 100 is made of a combination of resin and metal, and the central part constituting most of the back surface is constituted by the metal layer 102. Further, metal layers 101 and 103 are provided on both sides in the longitudinal direction (x direction) when viewed from the metal layer 102.

  The metal layers 101 to 103 constitute the same xy plane. The metal layer 101 and the metal layer 102 are opposed via the slit SL1, and the metal layer 102 and the metal layer 103 are opposed via the slit SL2. The slits SL1 and SL2 extend in the y direction on the back surface of the housing, and extend in the z direction on the side surface of the housing. As described above, the reason why the wide range of the back surface of the housing is constituted by the metal layers 101 to 103 is mainly for improvement of the mechanical strength, electromagnetic shielding characteristics, design, and the like of the housing.

  FIG. 2 is a plan view of the back surface of the portable wireless device 100 as viewed from the inside.

  As shown in FIG. 2, a solenoid coil 10 </ b> A is provided inside the mobile wireless device 100 so as to overlap the metal layer 102 in a plan view (as viewed from the z direction). The solenoid coil 10A and the metal layer 101 do not overlap. As shown in FIG. 3 which is a perspective view, the solenoid coil 10A is a thin coil pattern formed by winding a conductor 12 around a plate-like magnetic member 11 a plurality of turns, and its coil axis is directed in the x direction. The magnetic member 11 is a plate-like body having an xy plane, and is arranged so that one side extending in the y direction is positioned in the vicinity of the slit SL1. One end of the conductor 12 constitutes a first terminal 13, and the other end of the conductor 12 constitutes a second terminal 14. In the present embodiment, the conductor 12 and the metal layer 102 are insulated.

  However, the coil pattern used in the present invention is not limited to the solenoid coil 10A, and a meander coil 10B shown in FIG. 4 may be used. As shown in FIG. 5 in which the magnetic member 11 is omitted, the meander coil 10B includes a planar conductor 12 that is bent back and forth in the x direction. When the first terminal 13 of the conductor 12 is the starting point and the second terminal 14 is the ending point, the portion extending in the x-plus direction is up and the portion extending in the x-minus direction is down. If the member 11 is mounted while meandering in the z direction, a coil configuration similar to that of the solenoid coil 10A shown in FIG. 3 can be obtained. In this case, it is preferable to use a highly flexible sheet that can meander in the z direction as the magnetic member 11. Alternatively, the magnetic member 11 may be omitted from the meander coil 10B, and only the meander conductor 12 may be used.

  6 is a schematic diagram for explaining the direction of magnetic flux generated by the solenoid coil 10A, and FIG. 7 is a schematic diagram for explaining the direction of magnetic flux generated by the meander coil 10B.

  In the solenoid coil 10 </ b> A, currents in opposite directions flow through the conductor 12 a located above the magnetic member 11 and the conductor 12 b located below. Therefore, as shown in FIG. 6, the magnetic flux φ4 generated around each conductor 12 when a current is passed through the conductor 12 may be, for example, clockwise (clockwise) in the conductor 12a located above the magnetic member 11. For example, the conductor 12b located below the magnetic member 11 is counterclockwise (counterclockwise). For this reason, for example, a clockwise (clockwise) magnetic flux φ5 is also generated around the entire conductor 12a positioned on the upper side of the magnetic member 11, and left also on the entire periphery of the conductor 12b positioned on the lower side of the magnetic member 11. A rotating (counterclockwise) magnetic flux φ5 is generated. Since the magnetic member 11 is sandwiched between the conductors 12a and 12b, the direction of the magnetic flux φ5 passing through the magnetic member 11 coincides, and the direction of the magnetic flux φ6 generated as a whole of the solenoid coil 10A is one direction (FIG. 6). In the example shown in FIG.

  On the other hand, as shown in FIG. 7, in the meander coil 10B, there is no substantial difference in the position of each conductor 12 in the z direction, and the corrugated magnetic member 11 meanders between the conductors 12c and 12d adjacent in the x direction. Will intervene. Specifically, for the even-numbered conductor 12c, the magnetic member 11 is positioned on both sides in the x direction and on the lower side in the z direction, while for the odd-numbered conductor 12d, on both sides in the x direction and on the upper side in the z direction. The magnetic member 11 is located. Thereby, the upper and lower positions of the magnetic member 11 are alternately switched so that one of the adjacent conductors 12 c and 12 d is on the upper side of the magnetic member 11 and the other is on the lower side of the magnetic member 11.

  Since currents in opposite directions flow through the conductors 12c and 12d adjacent to each other in the x direction, as shown in FIG. 7, when the current flows through the conductor 12, the magnetic flux φ4 generated around each conductor 12 is For example, if the even-numbered conductor 12c is clockwise (clockwise), the odd-numbered conductor 12d is counterclockwise (counterclockwise). However, since the magnetic member 11 meandering in the z direction is interposed between the conductors 12c and 12d adjacent in the x direction, the magnetic flux φ5 generated above the magnetic member 11 and the magnetic flux generated below the magnetic member 11 φ5 does not cancel each other, and for example, a clockwise (clockwise) magnetic flux φ5 is generated around the entire even-numbered conductor 12c located above the magnetic member 11, and the odd-numbered odd-numbered located below the magnetic member 11 is generated. A counterclockwise magnetic flux φ5 is also generated around the entire conductor 12d. Since the magnetic member 11 is disposed so as to meander between the conductors 12c and 12d in the z direction, the direction of the magnetic flux φ5 passing through the magnetic member 11 matches, and the magnetic flux φ6 generated as a whole of the meander coil 10B. The direction is one direction (x minus direction in the example shown in FIG. 7).

  Thus, the meander coil 10B can be made thinner than the solenoid coil 10A because the position of each conductor 12 in the z direction is substantially constant. Moreover, since the magnetic member 11 meanders in the z direction, the spread in the z direction of the magnetic flux φ12 generated on the upper side of the magnetic member 11 and the magnetic flux φ12 generated on the lower side of the magnetic member 11 as shown in FIG. It is larger than the coil 10A, which makes it possible to obtain good antenna characteristics.

  FIG. 8 is a partial cross-sectional view of the portable wireless device 100.

  As shown in FIG. 8, the solenoid coil 10 </ b> A is bonded to the back surface of the metal layer 102 with an adhesive 15. A circuit board 20 parallel to the metal layers 101 and 102 is provided above the metal layers 101 and 102. Although many electronic components are mounted on the circuit board 20, only two electronic components 21 are shown in FIG. 8. The circuit board 20 covers both the metal layers 101 and 102 in plan view.

  FIG. 9 is a schematic perspective view for explaining the configuration of the antenna device according to the present embodiment.

  As shown in FIG. 9, on the main surface of the circuit board 20, in addition to the electronic component 21 shown in FIG. 8, an impedance matching circuit 22, an RFID transceiver circuit 23, a radio frequency transceiver transceiver 24, an inductance element 25a, 25b, etc. are mounted.

  The impedance matching circuit 22 is inserted in the wiring 26 and is used for impedance matching of the RFID antenna device. The impedance matching circuit 22 and the transmission / reception circuit 23 are connected by a wiring 27. For example, a frequency of 13.56 MHz is used for the RFID antenna device. The transmission / reception circuit 24 for high-frequency communication is a transmission / reception circuit for another antenna device that uses a different frequency band from the RFID antenna device, and the frequency band is, for example, several hundred MHz to several GHz. The inductance elements 25a and 25b are inserted into the wirings 28 and 25, respectively, and play a role of blocking signal components of high frequency communication. That is, the inductance elements 25a and 25b pass a signal in a frequency band (13.56 MHz) used for RFID, and have high impedance for a signal in a frequency band (several hundred MHz to several GHz) used for high-frequency communication.

  As shown in FIG. 9, one ends of the wirings 28 and 26 are connected to different regions 111 and 112 of the metal layer 101 through connection pins 31 and 32, respectively. On the other hand, the other ends of the wirings 28 and 26 are connected to terminals 13 and 14 of the solenoid coil 10A via connection pins 33 and 34, respectively. One end of the wiring 29 is connected to a further different region 113 of the metal layer 101 via the connection pin 35.

  The connection pins 31 to 35 are pin-shaped conductors that are fixed to the circuit board 20 and extend in the z direction, and have spring properties in the z direction. Accordingly, when the circuit board 20 and the metal layers 101 and 102 are overlapped with a predetermined interval in the z direction, the tips of the connection pins 31 to 35 abut on the corresponding regions on the metal layers 101 and 102, respectively. This establishes a connection in the z direction.

  With such a configuration, the terminal 13 of the solenoid coil 10 </ b> A and the region 111 of the metal layer 101 are connected to each other by the wiring pattern P <b> 1 including the connection pin 33, the wiring 28 and the connection pin 31. Similarly, the terminal 14 of the solenoid coil 10 </ b> A and the region 112 of the metal layer 101 are connected to each other by a wiring pattern P <b> 2 including the connection pin 34, the wiring 26, and the connection pin 32. Since the region 111 and the region 112 of the metal layer 101 are located on different planes, the wiring pattern P1, the metal layer 101, and the wiring pattern P2 constitute the loop antenna 10L, and both ends thereof are terminals of the solenoid coil 10A. 13 and 14, respectively.

  Since the loop antenna 10L having such a configuration is connected in series to the solenoid coil 10A, it functions as a part of an RFID antenna device. In this embodiment, since the wiring patterns P1, P2 constituting the loop antenna 10L cross the slit SL1 in plan view, most of the loop antenna 10L is covered with the metal layers 101, 102. Nevertheless, the magnetic flux that has passed through the narrow slit SL1 can be captured by the loop antenna 10L. Furthermore, a part of the magnetic flux that has passed through the slit SL1 is also sucked into the magnetic member 11 constituting the solenoid coil 10A.

  FIG. 10 is a schematic diagram showing a magnetic flux generated from an external reader / writer.

  FIG. 10 shows magnetic fluxes φ1 and φ2 emitted from the reader / writer. Of these, the magnetic flux φ1 is a magnetic flux that passes through the slit SL1, and the magnetic flux φ2 is a magnetic flux that strikes the metal layers 101 and 102. The magnetic flux φ1 that has passed through the slit SL1 passes through the inner diameter portion of the loop antenna 10L shown in FIG. 9 and is converted into a current. On the other hand, when the magnetic flux φ2 collides with the metal layers 101 and 102, a magnetic flux φ3 in the reverse direction is generated so as to cancel it. Since this magnetic flux φ3 goes from the front surface (lower surface in FIG. 10) to the back surface (upper surface in FIG. 10) of the metal layers 101 and 102 via the slit SL1, a part thereof is efficiently sucked into the solenoid coil 10A. That is, although the solenoid coil 10A is completely covered with the metal layer 102 in a plan view, a large amount of magnetic flux is converted into current by narrowing the distance from the slit SL1 in the x direction that is the coil axis. can do.

  As described above, in the present embodiment, the magnetic flux that has passed through the slit SL1 is captured by the loop antenna 10L and the solenoid coil 10A, and converted into a current. Accordingly, it is possible to ensure the communication distance of the RFID antenna device, even though most of the back surface of the portable wireless device 100 is covered with the metal layers 101 to 103.

  Further, the metal layer 101 constituting a part of the loop antenna 10L also functions as a radiation conductor of the antenna device for high frequency communication. In this case, it is necessary to separate a signal for high-frequency communication from the loop antenna 10L. In order to realize this, in this embodiment, inductance elements 25a and 25b are inserted into the wirings 28 and 26, respectively. As a result, since the wirings 28 and 26 have high impedance in the high frequency band, the signal components of both antennas can be separated.

  As described above, in the present embodiment, the loop antenna 10L is formed by the wiring patterns P1, P2 and the metal layer 101, and the inner diameter portion of the loop antenna 10L overlaps the slit SL1, so that the magnetic flux passing through the slit SL1 is captured. be able to. In addition, since the solenoid coil 10A is connected in series to the loop antenna 10L, it is possible to increase the communication distance as compared to the case where the loop antenna 10L alone is included.

  In the present embodiment, since the metal layer 101 constituting a part of the loop antenna 10L does not overlap the solenoid coil 10A in plan view, the area of the inner diameter portion of the loop antenna 10L in the xy plane is maximized. Can be Thereby, the magnetic flux that has passed through the slit SL1 can be effectively captured.

  Furthermore, in the present embodiment, the metal layer 101 is used as a part of the loop antenna 10L and also functions as a radiation conductor of the antenna device for high-frequency communication, so that it is possible to suppress an increase in the number of components. Become.

<Second Embodiment>
FIG. 11 is a schematic perspective view for explaining the configuration of the antenna device according to the second embodiment of the present invention.

  As shown in FIG. 11, in the antenna device according to the present embodiment, the tips of the connection pins 33 and 34 are in contact with different regions 121 and 122 of the metal layer 102 instead of the terminals 13 and 14 of the solenoid coil 10 </ b> A, respectively. On the other hand, the terminals 13 and 14 of the solenoid coil 10 </ b> A are both electrically connected to the metal layer 102. Since the other configuration is the same as that of the first embodiment described above, the same reference numeral is given to the same element, and a duplicate description is omitted.

  In the present embodiment, the connection pins 33 and 34 are not directly connected to the terminals 13 and 14 of the solenoid coil 10 </ b> A, but are connected via the metal layer 102. Even with such a configuration, the same effects as those of the first embodiment can be obtained, and the layout flexibility of the connection pins 33 and 34 can be greatly increased. Also, the inner diameter size of the loop antenna 10L can be enlarged.

  In the present embodiment, both the connection pins 33 and 34 are connected to the metal layer 102, but only one of the connection pins 33 and 34 is connected to the metal layer 102 and the other is connected to the terminal 13 of the solenoid coil 10A or 14 may be connected.

  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 the first and second embodiments, the electronic components 21 to 25 and the wirings 26 to 29 are formed on the upper surface of the circuit board 20. That is, it may be formed on the surface facing the metal layers 101 and 102.

  In the first and second embodiments, the solenoid coil 10A (or the meander coil 10B) is completely covered with the metal layer 102. However, this point is not essential in the present invention, and the solenoid coil 10A ( Alternatively, only a part of the meander coil 10 </ b> B) may be covered with the metal layer 102 or may not be covered with the metal layer 102. However, since it is difficult to obtain sufficient antenna characteristics when the metal layer 102 having a large area is present, the present invention is particularly effective in such a configuration. Rather, as described with reference to FIG. 10, the solenoid coil 10A (or the meander coil 10B) is completely covered with the metal layer 102, and is disposed close to the slit SL1, thereby capturing more magnetic flux. Can do.

  Furthermore, in the first and second embodiments, the metal layers 101 and 102 constitute a part of the casing of the portable wireless device 100, but this point is not essential in the present invention. Further, it is not essential to attach the solenoid coil 10A (or the meander coil 10B) to the metal layer 102, and it may be mounted on the circuit board 20.

10A solenoid coil 10B meander coil 10L loop antenna 11 magnetic member 12, 12a-12d conductor 13, 14 terminal 15 adhesive 20 circuit board 21 electronic component 22 impedance matching circuit 23, 24 transmission / reception circuit 25 inductance element 26-29 wiring 31-35 Connection pin 100 Portable wireless device 101-103 Metal layers 111-113, 121, 122 Regions P1, P2 Wiring patterns SL1, SL2 Slits φ1-φ6 Magnetic flux

Claims (15)

A first metal layer having first and second regions;
A coil pattern having first and second terminals;
A first wiring pattern connected between the first region of the first metal layer and the first terminal of the coil pattern;
A second wiring pattern connected between the second region of the first metal layer and the second terminal of the coil pattern;
An antenna device, wherein at least a part of a loop antenna is formed by the first metal layer, the first wiring pattern, and the second wiring pattern.   The antenna device according to claim 1, wherein the coil pattern does not overlap the first metal layer in plan view.   The antenna device according to claim 1, further comprising a first transmission / reception circuit connected to the first or second wiring pattern.   The antenna device according to claim 3, further comprising a second transmission / reception circuit connected to the first metal layer and having a frequency band of a signal to be transmitted / received different from that of the first transmission / reception circuit.   The antenna apparatus according to claim 4, further comprising an inductance element inserted into the first or second wiring pattern. A circuit board parallel to the first metal layer;
The first wiring pattern is perpendicular to the first wiring formed on the circuit board and to the circuit board, and the first wiring pattern includes one end of the first wiring and the first metal layer. A first connection pin connecting the region,
The second wiring pattern is perpendicular to the second wiring formed on the circuit board and to the circuit board, and the second wiring pattern includes one end of the second wiring and the second metal layer. The antenna device according to claim 1, further comprising a second connection pin that connects the region. The first wiring pattern is further perpendicular to the circuit board, and further includes a third connection pin that connects the other end of the first wiring and the first terminal of the coil pattern;
The second wiring pattern further includes a fourth connection pin that is perpendicular to the circuit board and connects the other end of the second wiring and the second terminal of the coil pattern. The antenna device according to claim 6.   The first metal layer according to any one of claims 1 to 7, further comprising a second metal layer that faces the first metal layer through a slit and forms the same plane as the first metal layer. The antenna device described.   9. The antenna device according to claim 8, wherein at least a part of the coil pattern overlaps the second metal layer in plan view.   The first region of the first metal layer and the first terminal of the coil pattern are connected via at least the first wiring pattern and the second metal layer, whereby the first 10. The loop antenna according to claim 7, wherein at least a part of the loop antenna is formed by the metal layer, the second metal layer, the first wiring pattern, and the second wiring pattern. The antenna device according to 1.   The antenna device according to any one of claims 1 to 10, wherein the coil pattern includes a solenoid coil formed by winding a conductor around a plate-like magnetic member.   The antenna device according to claim 1, wherein the coil pattern includes a meandering conductor.   The antenna device according to claim 12, wherein the coil pattern further includes a wavy magnetic member, and the upper and lower positions of the magnetic member and the conductor are alternately switched between adjacent conductors.   A portable wireless device comprising the antenna device according to any one of claims 1 to 13.   The portable wireless device according to claim 14, wherein the first metal layer constitutes a part of a housing.

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