JP4807463B2 - Antenna device - Google Patents

Description

  The present invention relates to an RF-ID, that is, a wireless communication medium processing apparatus that performs communication with a wireless communication medium such as an IC card or an IC tag, or an antenna apparatus used for the wireless communication medium itself.

  In recent years, mobile terminals such as mobile phones that have built-in RF-ID wireless tags and those that have a function of reading non-contact IC cards and IC tags have become widespread. An antenna device in which a magnetic sheet is bonded (the coil axis of a loop-shaped antenna is perpendicular to the magnetic sheet) is often used.

  However, when the metal body is close to the back surface of the antenna, the communication performance is likely to deteriorate, and if the magnetic sheet is thickened to prevent this, the miniaturization / thinning of the portable terminal is hindered.

  In view of this, an antenna device using a coil having a coil axis horizontal to an adjacent metal surface has been devised, such as (Patent Document 1) focusing on the magnetic field distribution in the vicinity of the metal body.

JP 2008-048376 A

  However, since the structure of (Patent Document 1) uses a coil having a coil axis that is horizontal to the metal surface, the communication performance when not close to the metal body is magnetic on the opening surface of the loop antenna. It is inferior compared with the thing using the conventional antenna which bonded the body sheet. For this reason, if the planned antenna mounting location is changed due to a design change, etc., the same antenna cannot be used, resulting in problems such as the need to redo the selection of the antenna, which hinders development. There is a fear.

  In view of the above problems, an object of the present invention is to provide an antenna device having good communication performance regardless of the distance between the antenna and the metal body.

In order to solve the above-mentioned problems, the present invention provides a loop antenna having an opening surface surrounded by four sides of a rectangular shape or a square shape by winding a conductor in one turn or a plurality of turns, and a line for each turn of the antenna. And at least two coils inserted on two sides facing each other, each coil being wound up in an upright state on the opening surface of the antenna and parallel to the opening surface In addition, the antenna device has a coil axis that extends from the outside to the inside of the opening surface and is substantially perpendicular to the direction of the side into which the coil is inserted .

  ADVANTAGE OF THE INVENTION According to this invention, the antenna apparatus which has favorable communication performance can be provided irrespective of the distance of an antenna and a metal body.

The conceptual diagram of the antenna apparatus in the Example of this invention Result graph of winding number experiment The conceptual diagram of the antenna apparatus in the Example of this invention Conceptual diagram of the present invention when transmitting from an antenna when a metal object is in a distance Conceptual diagram of the present invention when the antenna is subjected to a magnetic field from the outside when the metal body is far away Conceptual diagram of the present invention when transmitting from an antenna when a metal body is in the vicinity Conceptual diagram of the present invention when an antenna receives a magnetic field from the outside when a metal body is in the vicinity Conceptual diagram of a conventional example when transmitting from an antenna when a metal body is in the vicinity Conceptual diagram of a conventional example when a metal body is in the vicinity and the antenna receives a magnetic field from the outside The conceptual diagram of the antenna apparatus in the Example of this invention The conceptual diagram of the antenna apparatus in the Example of this invention Experiment result graph of distance to substrate and magnetic field strength Experimental result graph of angle and magnetic field strength Conceptual diagram of the antenna device of the present invention in an experiment Conceptual diagram of conventional example in experiment Image of communication between terminals Perspective view when the mobile terminal is disassembled The conceptual diagram of the antenna apparatus in the Example of this invention

According to the present invention, the conductor is wound in one turn or a plurality of turns and has a loop-shaped antenna having an opening surface surrounded by four sides of a rectangular shape or a square shape, and on the line for each turn of the antenna, And at least two coils inserted on two sides facing each other, each coil being wound up in an upright state on the opening surface of the antenna, parallel to the opening surface and the opening The antenna device has a coil axis that extends from the outside to the inside of the surface and is substantially perpendicular to the direction of the side into which the coil is inserted . An antenna device having good communication performance can be provided regardless of the distance.

  In addition, since the lengths of the two coils in the longitudinal direction are equal, the bias in the communication performance of the antenna device can be reduced.

In addition, since the conductors constituting the coil are wound by a number of turns that is approximately a half turn greater than one or more rounds , the coil terminals can be provided at both ends of the coil, thereby constituting a loop-shaped antenna. Can be easily inserted into the track.

Furthermore, a metal body was provided on one surface of the opening surface of the loop-shaped antenna, and the number of conductors wound on the metal body side surface of the coil was wound on the surface opposite to the metal body side surface. By being less than the number of conductors, the coil can efficiently create a magnetic field and can efficiently capture the magnetic field.

  In addition, since one side of the loop-shaped antenna is a coil, the opening of the coil can be made large, and the performance of the antenna device can be improved.

  In addition, when the loop-shaped antenna is arranged close to the metal body, the coil is located at the end of the metal body, so that a portion where the eddy current density of the metal body is high can be used. Therefore, an antenna device having good communication performance can be provided.

  In addition, since the centers of the winding axes of the two coils are shifted, the magnetic fields generated in the two coils in different directions do not interfere with each other, and the design flexibility can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a conceptual diagram of an antenna device according to an embodiment of the present invention.

  The loop-shaped antenna 1 provides a path through which current flows from the antenna input / output terminal 4 (or 5) to the other antenna input / output terminal 5 (or 4). It is defined that a signal is transmitted and received by a current generated by a magnetic field from. Further, a surface surrounded by the line of the loop-shaped antenna 1 is defined as an opening surface of the loop-shaped antenna 1.

  In other words, in this embodiment, the loop antenna 1 is adjusted so that, for example, RFID (13.56 MHz) radio waves can be transmitted and received.

  In this embodiment, the loop antenna 1 is rectangular, but may be square.

  In this embodiment, two places are inserted together with the core 3 around which the coil portion 2 is wound in the middle of the line constituting the loop-shaped antenna 1. Assuming that the coil axis of one coil part 2 is A, the arrangement of the coil part 2 is such that the coil axis A is parallel to the opening surface of the loop antenna 1 and the coil of the line of the loop antenna 1 is It is perpendicular to the direction of current flowing through the inserted front and rear portions (in this embodiment, the direction of C in FIG. 1).

  In this embodiment, the coil axis A is perpendicular to the C direction, but may not be parallel.

  In the present embodiment, the coil portion 2 is disposed so as to be perpendicular to the end surface B of the metal body 6 disposed at a distance D. Although the distance D can be considered from 0 mm to ∞, as will be described later, in any case, the antenna device has good communication performance.

  In addition, the magnetic material used for the core 3 can be increased because the magnetic flux passing through the coil portion 2 can be increased, and the communication performance is improved when a metal body is in close proximity. It may be composed of.

  In the present invention, two or more coil portions 2 are provided, and at least two coil portions 2 are opposed to each other. Further, as is apparent from FIG. 1, the coil portion 2 is provided on the opposite sides of the four sides of the loop antenna 1 except for the sides where the antenna input / output terminals 4 and 5 are provided. By arranging in this way, the communication distance on the left and right of the terminal can be balanced. Furthermore, since the coils are arranged on different sides of the metal body, it is preferable that the magnetic field caused by the induced eddy current can be efficiently captured.

  Further, in FIG. 1, the two coil portions 2 have the same shape, that is, the same size core 3 is used so that the length of the coil portion 2 in the longitudinal direction is the same. The number of times may be different. However, it is preferable to use the coil portion 2 having the same shape because an attachment error at the time of mass production and a reduction of parts types can be achieved.

  In addition, in this embodiment, the number of windings of the conductor of the coil portion 2 is illustrated with about 1.5 turns, and the number of conductors wound on the surface of the core 3 facing the metal body (the surface of the core 3 facing the metal body). The number of conductors wound on the surface when the conductor is wound around the core 3 is less than the number of conductors wound on the surface opposite to the surface facing the metal body of the core 3. Yes.

  By comprising in this way, it can be set as an efficient antenna device with few winding times.

  In FIG. 1, the longitudinal direction of the rectangular parallelepiped core 3 is arranged on the loop-shaped antenna 1, but the short side direction may be arranged, and the coil unit 2 may be arranged according to desired characteristics and mounting space. The shape of the core 3 can be freely selected.

  However, when the short side direction is arranged, it goes without saying that the coil part 3 is wound around the short side direction of the core 3.

  Here, the results of the winding number experiment are shown in FIG. The horizontal axis plotted the number of windings, and the vertical axis plotted the values normalized by the magnetic field strength at 0.5 windings. The coil part 2 used in the experiment uses 21 mm × 4 mm × 0.2 mm ferrite for the core 3, and a 0.1 mm-thick copper thin plate is changed from 1 mm to 0.6 mm in width according to the number of turns. did. Coil portion 2 is placed close to the end of the metal body, 50Ω is matched at 13.56 MHz, a 20 dBm sine wave signal is input from the signal generator to the antenna at 13.56 MHz, and the main surface of the metal body is The magnetic field strength in the sky 30 mm was measured.

  As shown in FIG. 2, the magnetic field strength increases as the number of turns increases. However, considering the rate of increase, it can be seen that when the number of windings increases from an integer by a half turn, it greatly increases. Although the conductor on the side not facing the metal body 6 is less affected by the eddy current on the surface of the metal body 6, the conductor of the coil portion 2 on the side facing the metal body 6 is affected by the eddy current on the surface of the metal body 6. Since a current in the direction of cancellation is generated, it can be estimated that the increase in magnetic field strength is small when the number of turns is an integral multiple.

  Here, the experiment of FIG. 2 was performed in a state where the loop-shaped antenna 1 was not formed. However, even when the loop-shaped antenna 1 is formed, the influence of the coil portion 2 from the metal body 6 is considered similarly. Therefore, it can be said that the coil unit 2 inserted in the loop-shaped antenna 1 can be an efficient antenna device with a small number of turns.

  However, the number of turns is not limited, and the number of turns may be more or less than about 1.5 turns shown in FIG.

  Note that increasing or decreasing the number of turns by about 0.5 turns from the integral multiple is possible because both ends of the coil portion 2 (connection portion with the loop-shaped antenna 1) can be formed on both sides with the core 3 interposed therebetween, so It becomes easy to insert into the antenna 1.

  That is, since it can be inserted in such a way as to replace the straight portion of a normal loop antenna, it becomes easier to insert.

  Moreover, about the winding method of the coil part 2, it may be right-handed or left-handed, and can be suitably selected according to the position to arrange | position.

  Further, the connection between the coil portion 2 and the conductor of the loop-shaped antenna 1 can be performed by a commonly used connection method such as connection by solder or a connector. Alternatively, the coil portion 2 and the loop-shaped antenna 1 may be formed by a single connected conductor. As is generally known, the antenna input / output terminals 4 and 5 are connected to the matching circuit and the input / output terminals of the IC, and the connection method is contact or soldering with a pin or a spring, connection with a connector, or the like. A commonly used connection method can be used.

  FIG. 3 is a conceptual diagram of an antenna device according to an embodiment of the present invention.

  A loop-shaped antenna 1, a coil portion 2, a core 3, and antenna input / output terminals 4, 5 are arranged in the vicinity of the metal body 6. The coil portion 2 is disposed so as to be positioned at the end portion of the metal body 6. When a magnetic field in a direction perpendicular to the opening surface of the loop antenna 1 comes from the outside, an eddy current is generated on the surface of the metal body 6. Since the density of the eddy current is higher at the end of the metal body 6, the eddy current flowing on the surface of the metal body 6 is most efficiently arranged by placing the coil portion 2 at the end of the metal body 6. It is preferable because it can be used well. Moreover, since the density of the eddy current is low in the quadruple portion of the metal body 6, it is preferable to avoid the arrangement of the coil portion 2 in the quadruple portion.

  FIG. 3 assumes a mobile terminal in which it is difficult to secure a gap between the antenna device and the metal body 6. In this case, the metal body 6 is a substrate in the mobile terminal, for example. A liquid crystal display panel or the like may be used. The conductor constituting the loop-shaped antenna 1 may be composed of a coated copper wire or the like, but may be an electrode pattern or the like formed on the metal body 6. The coil unit 2 and the magnetic core 3 may also be mounted on the metal body 6. Although not shown, other components such as a camera module, a speaker, an RF module, an antenna for other frequencies, and the like can be mounted in a vacant space inside the loop of the loop antenna 1.

  Next, the operation concept of the antenna device of the present invention will be described with reference to FIGS.

  FIG. 4 is a conceptual diagram of the present invention when transmitting from an antenna when the metal body is far away. A current 7 flows through the loop antenna 1 due to a signal input to the antenna input / output terminals 4 and 5, and a magnetic field 8 is generated. Since the magnetic field 13 generated by the coil unit 2 is orthogonal to the magnetic field 8, there is no influence on the magnetic field 8. Although an eddy current 9 is generated in the metal body 6 in a direction that cancels the magnetic field 8 caused by the current 7, it does not have a great influence because it is far away. Therefore, when the metal body 6 is far away, communication is performed in the same manner as a conventional loop antenna, so that the antenna device of the present invention can obtain a good communication state even when the metal body is far away.

  FIG. 5 is a conceptual diagram of the present invention when the metal body is far away and the antenna receives a magnetic field from the outside. The magnetic field 10 from the outside and the magnetic field 11 passing through the loop-shaped antenna 1 have a relationship according to the distance. A current 7 is induced in the loop-shaped antenna 1 by the magnetic field 11, and the antenna input / output terminals 4, 5 are connected. Go out through. Since the coil axis of the coil portion 2 is orthogonal to the magnetic field 11, the current 7 is not affected. An eddy current 9 caused by the magnetic field 10 is generated in the metal body 6, and a magnetic field 12 in the opposite direction is formed. Therefore, when the metal body 6 is far away, communication is performed in the same manner as a conventional loop antenna, so that the antenna device of the present invention can obtain a good communication state even when the metal body is far away.

  That is, in this embodiment, the coil portion 2 is arranged so that a current is generated in a direction that cancels the eddy current 9.

  FIG. 6 is a conceptual diagram of the present invention when transmitting from an antenna when a metal body is in the vicinity. A current 7 flows through the loop antenna 1 due to a signal input to the antenna input / output terminals 4 and 5, and a magnetic field 8 is generated. An eddy current 9 is generated in the metal body 6 in a direction that cancels the magnetic field 8 caused by the current 7. As a result, the magnetic field 8 should be reduced and the communication performance of the antenna should be deteriorated. A magnetic field 13 penetrating the coil portion 2 is generated, and an electric current 14 is generated in the metal body 6 by the magnetic field 13. Since the current 14 is opposite to the eddy current 9 and cancels out, the magnetic field 8 is less affected by the eddy current 9 as a result. Therefore, even when the metal body 6 is in the vicinity, the antenna device of the present invention can obtain a good communication state.

  FIG. 7 is a conceptual diagram of the present invention when a metal body is in the vicinity and the antenna receives a magnetic field from the outside. A current 7 is generated in the loop antenna 1 and an eddy current 9 is generated in the metal body 6 by the magnetic field 10 from the outside. Since the metal body 6 and the loop-shaped antenna 1 are close to each other, the magnetic field 11 passing through the loop-shaped antenna 1 is reduced by the magnetic field 12 in the opposite direction due to the eddy current 9, and as a result, the current 7 should be reduced. However, when the magnetic field generated by the eddy current 9 passes through the coil part 2, a current that creates the magnetic field 13 flows through the coil part 2, and as a result, the current 7 does not decrease. Therefore, even when the metal body 6 is in the vicinity, the antenna device of the present invention can obtain a good communication state.

  As a comparative example, FIG. 8 is a conceptual diagram of a conventional example in the case of transmitting from an antenna when a metal body is in the vicinity. When away from the metal body, of course, it is not affected by the metal body. However, as shown in FIG. 8, a current 7 flows to the loop-shaped antenna 101 by a signal input to the antenna input / output terminals 4 and 5. A magnetic field 8 is generated. An eddy current 9 is generated in the metal body 6 in a direction that cancels the magnetic field 8 caused by the current 7. As a result, the magnetic field 8 becomes smaller and the communication performance of the antenna deteriorates. Therefore, when the metal body 6 is in the vicinity, sufficient communication performance cannot be obtained with the conventional loop antenna 101.

  FIG. 9 is a conceptual diagram of a conventional example when the metal body is in the vicinity and the antenna receives a magnetic field from the outside. A current 7 is generated in the loop antenna 101 and an eddy current 9 is generated in the metal body 6 by the magnetic field 10 from the outside. Since the metal body 6 and the loop-shaped antenna 101 are close to each other, the magnetic field 11 passing through the loop-shaped antenna 101 is reduced by the magnetic field 12 in the opposite direction due to the eddy current 9, and as a result, the current 7 is decreased. Therefore, when the metal body 6 is in the vicinity, sufficient communication performance cannot be obtained with the conventional loop antenna 101.

  In the situation of FIG. 8 or FIG. 9, it is common to use a magnetic sheet to reduce the influence of the metal body 6, but the area occupied by the antenna and the thickness increase, so that the cellular phone equipped with the antenna, etc. It becomes difficult to reduce the size.

  In the state of FIGS. 6 and 7 as the present embodiment, it can be said that the metal body 6 is used as an antenna by utilizing the current flowing through the metal body 6. Since a metal body in a mobile terminal is often larger than an antenna device, it can be considered that the use of a large metal body as an antenna device with an antenna having a small occupied area can greatly contribute to the future miniaturization and thinning of the mobile terminal.

  In each of the above drawings, the loop-shaped antenna 1 is drawn in one turn, but the number of turns is not limited to one turn, and may be a plurality of turns. In the case of a plurality of turns, only a part of the outermost line of the loop antenna 1 is configured by the coil part 2 or is inserted into the line of each turn so that the coil axis of each coil part 2 is common. Such an arrangement is preferable because deterioration in communication performance when a metal body is in close proximity is reduced. Further, although shown by one line, it is for simplification of the drawing, and actually has a width and thickness.

  Here, the arrangement of the antenna device of the present invention will be described. In addition to the arrangement as described above, as shown in FIG. 10, the center of the winding axis of the coil portion 2 may be shifted so as to face each other. That is, it is only necessary to shift the antenna when the antenna is arranged on the side of the loop-shaped antenna 1.

  Further, as shown in FIG. 11, all of one side of the square loop antenna 1 may be replaced with the coil portion 2.

  Thereby, the magnitude | size of the opening part of the loop-shaped antenna 1 can be taken large, and communication performance can be improved.

  The coil portion 2 may be disposed on the side facing the antenna input / output terminals 4 and 5.

  FIG. 12 shows the results of experiments using the antenna apparatus of the present invention and a comparative antenna configured with a conventional structure configured only with a loop-shaped antenna. The horizontal axis shows the distance between the metal body and the antenna, and the vertical axis shows the magnetic field strength measured 30 mm above the antenna when the antenna is matched to 50Ω at 13.56 MHz and a 13.56 MHz, 20 dBm sine wave signal is input. Are plotted.

  The antenna device of the present invention used for the experiment has a loop outer shape of 40 mm × 25 mm, two 25 mm sides, a 21 mm × 4 mm × 0.2 mm magnetic core with a line width of 1 mm and a thickness of 0.1 mm. A prototype was produced with the configuration as shown in Example 1 of FIG. 1, in which a copper thin plate was used to replace each coil wound by 1.5 turns. A comparative antenna having a conventional structure was prototyped in one turn using a copper thin plate having an outer shape of 40 mm × 25 mm, a line width of 1 mm and a thickness of 0.1 mm. A solid substrate having a size assumed to be a 40 mm × 110 mm portable terminal was used as the metal body.

  As can be seen from FIG. 12, the magnetic field strength is less than 1/10 and the communication characteristics cannot be maintained when approaching as compared with the case where the conventional one is away from the metal body. Thus, in the antenna device of the present invention, the deterioration of the magnetic field strength is small even when the metal body approaches, and the communication characteristics can be maintained even when the metal body is close. Therefore, it can be said that the present invention can provide an antenna device having good communication performance regardless of the distance between the antenna and the metal body.

  Next, the communication range of the present invention will be described with reference to FIGS.

  FIG. 13 shows the result of measuring the magnetic field strength from 0 ° to 90 ° at a distance of 30 mm from the side surface of the antenna by arranging the antenna used in the experiment of FIG. 12 as shown in FIG. 14 and FIG. As the substrate 27, a solid substrate of 40 mm × 110 mm size imitating a portable terminal is used. In the measurement of the comparative antenna having the conventional configuration, the magnetic field strength in the 0 ° direction is almost the same as that in FIG. As shown, a 41 mm × 26 mm × 0.2 mm magnetic sheet is inserted between the loop antenna 101 and the substrate 27.

  As can be seen from FIG. 13, the antenna device of the present invention has a magnetic field strength in the 90 ° direction that is stronger than the comparative antenna of the conventional configuration. This is thought to be because the magnetic field in the 90 ° direction was strengthened because the coil axis was parallel to the substrate.

  That is, conventionally, the coil axis of the loop antenna is perpendicular to the substrate, so that the communication characteristics can be maintained in the direction perpendicular to the substrate (that is, the 0 ° direction), but in the case of the 90 ° direction. However, in this embodiment, the coil axis of the coil portion coincides with the direction of the magnetic field in the case of the 90 ° direction, since the coil axis of the loop antenna is perpendicular to the direction of the magnetic field. Therefore, communication characteristics can be maintained.

  As shown in FIG. 16, this is advantageous in communication between terminals (peer-to-peer) in which terminals 28 and 29 are arranged side by side while exchanging data while looking at the screen. The present invention can be said to be very effective because it is compatible with communication in the rear direction of the terminal such as a ticket gate (0 ° direction in FIG. 13).

  Next, the case where the antenna device of the present invention is mounted on a portable terminal will be described in detail. FIG. 17 is a perspective view when the portable terminal in the embodiment of the present invention is disassembled.

  The portable terminal 20 includes a liquid crystal panel 21, operation buttons 22, a casing 25 and a casing 26, a substrate 23 accommodated therein, a battery 24, and the like. The loop-shaped antenna 1, the coil portion 2, the core 3, and the antenna input / output terminals 4 and 5 according to the present invention are formed inside the housing 26. The loop-shaped antenna 1 line and antenna input / output terminals 4 and 5 are formed by sheet metal, metal foil tape, printing, or the like, and the coil portion 2 is a predetermined part of the casing 25 by sticking with adhesive tape or fixing with screws. Attach to the place. The connection of the loop-shaped antenna 1 line and the coil portion 2 is performed by contact connection such as a connector or crimping, or soldering or welding, and the connection between the antenna input / output terminals 4 and 5 and the IC is made by pin contact. In addition, connector connection, soldering of conductive wires, etc. are conceivable.

  In FIG. 17, the base 23 is provided with the loop-shaped antenna 1 line and antenna input / output terminals 4 and 5, and is connected to the coil portion 2 provided in the housing 25 by a pin, so that the loop-shaped antenna is provided. 1 is formed.

  Components such as an RF-ID IC, a matching circuit, an antenna for other frequencies, a camera unit, a speaker, and an RF module are arranged in the space formed between the housing 26 and the substrate 23. These components and the loop-shaped antenna 1 are arranged. And good communication can be performed even if the coil part 2 and the core 3 are in contact or separated.

  In this embodiment, a loop antenna is used. However, as shown in FIG. 18, the terminal 16 of the coil unit 2 mounted on the metal body 6 is connected to the ground of the metal body 6. You may make it a shape.

  In this case, considering the case where the terminals 16 are connected to each other by the coated copper wire in close contact with the metal body 6, there is no current induced by the copper wire in this portion, so the potentials of the terminals 16 may be equal. Recognize.

  Accordingly, the terminal 16 can be connected to the metal body 6, and the antenna input / output terminal 4 passes through the coil portion 2 and the terminal 16, passes through the metal body 6, and passes through the other terminal 16 and the coil portion 2. A loop path leading to the output terminal 5 is formed. By doing so, a part of the conductor of the loop antenna 1 can be omitted, and the terminal design can be simplified.

  According to the antenna device of the present invention, since the communication characteristics of the antenna can be maintained regardless of the distance between the antenna and the metal body in the casing on which the antenna is mounted, the antenna of various electronic devices such as mobile phones can be maintained. Useful as.

DESCRIPTION OF SYMBOLS 1 Loop-shaped antenna 2 Coil part 3 Core 4, 5 Antenna input / output terminal 6 Metal body 7, 14 Current 8, 10, 11, 12, 13 Magnetic field 9 Eddy current 16 Terminal 20 Portable terminal 21 Liquid crystal panel 22 Button 23 Board | substrate 24 Battery 25, 26 Case 27 Board

Claims (7)

A loop-shaped antenna having an opening surface surrounded by four sides of a rectangular or square shape by winding a conductor in one turn or a plurality of turns;
And at least two coils inserted on two sides opposite to each other on a line for each turn of the antenna,
Each of the coils is wound and arranged in an upright state on the opening surface of the antenna, is parallel to the opening surface and communicates from the outside to the inside of the opening surface , and the side where the coil is inserted An antenna device having a coil axis substantially perpendicular to a direction . The antenna device according to claim 1, wherein the two coils have the same length in the longitudinal direction. The antenna device according to claim 1, wherein the conductor constituting the coil is wound by a number of turns that is approximately a half turn more than one turn or a plurality of turns. A metal body is provided on one surface of the opening surface of the loop-shaped antenna, and the number of the conductors wound on the surface of the coil on the metal body side is wound on a surface opposite to the surface on the metal body side. The antenna device according to claim 3, wherein the number is less than the number of the turned conductors. 2. The antenna device according to claim 1, wherein one side of the loop-shaped antenna is a coil. 2. The antenna device according to claim 1, wherein the coil is located at an end of the metal body when the loop-shaped antenna is arranged close to the metal body. The antenna device according to claim 1, wherein the centers of the winding axes of the two coils are shifted from each other.

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