Antenna portable terminal using the same

Field

0001The present invention relates to an antenna for use in RF-ID (Radio Frequency Identification) and NFC (Near Field Communication), as well as to a portable terminal using the same.

Background

0002In recent years, a loop antenna has frequently been used in a portable terminal, like a portable phone and a smart phone, in order to read information from a non-contact IC card and an IC tag and exchange information with a reader/writer.

0003In general, the loop antenna is smaller than the non-contact IC card, and a magnetic field capture area (a communicable area) is narrow. For these reasons, when the loop antenna reads information from; for instance, a non-contact IC card, difficulty is often encountered in reading information.

0004Accordingly, in order to expand the communicable area, a combination of the loop antenna with a metallic line is available (see; for instance, <patcit id="pcit0001" dnum="JP2008028506A"><text>JP-2008-28506A</text></patcit>). However, since the communicable area is expanded by use of the metallic line in the related art structure, an air field where the metallic area is absent exists in the vicinity of the expanded area.

0005For this reason, if a transmission magnetic field originating from the non-contact IC card enters the air field, dielectric electromotive force originating from a magnetic flux from the IC card hardly develops in the loop antenna. As a consequence, even when a communication area is expanded, there is a potential of the loop antenna being unable to establish a communication with the IC card in the air field.

Summary

0006The present teachings have been arrived at in the knowledge of drawbacks and limitations of known systems.

0007According to the present disclosure, there can be provided an antenna that exhibits superior communication performance within a communicable area while expanding the communicable area as well as a portable terminal using the antenna. According to a first aspect, there can be provided an antenna comprising a loop antenna having an aperture; a metallic body that is electrically insulated from the loop antenna and that is placed on one side where the aperture of the loop antenna is provided; and a notch that is smaller than an outer shape of the loop antenna and that is coupled with a periphery of the metallic body, wherein the loop antenna is placed on the metallic body so as to cover the notch.

0008Thereby, it is possible to provide an antenna that exhibits superior communication performance within a communicable area because an air field in the communicable area is reduced while expanding the communicable area and provide to a portable terminal using the antenna.

0009Viewed from another aspect, apparatus and method con be provided to cause an electric current oriented in a direction to cancel an electric current flowing through a loop antenna to flow through the notch, whereby an electric current oriented in the same direction as that of the electric current flowing through the loop antenna flows through the entire metallic body, so that the antenna pattern can be apparently made greater.

0010Viewed from a further aspect, there can be provided apparatus and method capable of easily generating an eddy current flowing through a metallic body, so that more superior communication performance is exhibited within a communicable area.

0011Viewed from another aspect, there can be provided apparatus and method capable of allowing a loop antenna oppose a metallic body without fail, whereby much superior communication performance is exhibited within a communicable area. Viewed from another aspect, there can be provided apparatus and method to allow a loop antenna oppose a metallic body without fail in the greatest area, so that extremely superior communication performance is exhibited within a communicable area.

Brief description of the figures

0012Examples in accordance with the present teachings will now be set forth by reference to the accompanying drawings, in which: <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Fig. 1</figref> is an oblique perspective view of an antenna of a first embodiment;</li><li><figref idref="f0001">Fig. 2</figref> is a top view of the antenna of <figref idref="f0001">Fig 1</figref>;</li><li><figref idref="f0002">Fig. 3</figref> is a side view of the antenna of <figref idref="f0001">Fig 1</figref>;</li><li><figref idref="f0002">Fig. 4</figref> is a view explaining a concept achieved when the antenna of the first embodiment emits a magnetic field;</li><li><figref idref="f0003">Fig. 5</figref> is a view explaining a concept achieved when the antenna of the first embodiment receives a magnetic field;</li><li><figref idref="f0004">Fig. 6</figref> is a view showing magnetic field intensity emitted by the antenna of the first embodiment;</li><li><figref idref="f0005">Fig. 7</figref> is an exploded perspective view of a portable terminal using the antenna of the first embodiment;</li><li><figref idref="f0006">Fig. 8</figref> is an oblique perspective view of the antenna of a second embodiment;</li><li><figref idref="f0006">Fig. 9</figref> is a plan view of the antenna of <figref idref="f0006">Fig 8</figref>;</li><li><figref idref="f0007">Fig. 10</figref> is a side view of the antenna of <figref idref="f0006">Fig 8</figref>;</li><li><figref idref="f0007">Fig. 11</figref> is a view for explaining a concept achieved when the antenna of the second embodiment emits a magnetic field;</li><li><figref idref="f0008">Fig. 12</figref> is a view explaining a concept achieved when the antenna of the second embodiment receives a magnetic field;</li><li><figref idref="f0009">Fig. 13</figref> is a view showing magnetic field intensity emitted by the antenna of the second embodiment;</li><li><figref idref="f0010">Fig. 14</figref> is an exploded perspective view of a portable terminal using the antenna of the second embodiment; and</li><li><figref idref="f0011">Fig. 15</figref> is a view showing magnetic field intensity emitted by another antenna of the second embodiment.</li></ul>

0013While the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are herein described in detail. It should be understood, however, that drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims.

Detailed description

0014An antenna according to selected examples of the present disclosure can include a loop antenna having an aperture and a metallic body that is electrically insulated from the loop antenna and that is provided on one side where the aperture of the loop antenna is provided. A notch that is smaller than an outer shape of the loop antenna and that is coupled with a periphery of the metallic body is provided on the metallic body. The loop antenna is placed on the metallic body so as to cover the notch.

0015It thereby becomes possible to reduce an air field within a communicable area while the communicable area is being expanded, so that an antenna exhibiting superior communication performance within a communicable area can be provided. Further, the notch is substantially identical in size with the aperture of the loop antenna, whereby the antenna can be coupled with the metallic body with superior efficiency, so that electric power induced in the metallic body by an external magnetic field can be transmitted to the antenna with superior efficiency.

0016The antenna is provided within enclosures, and the metallic body is provided on a back side of one of the enclosures, whereby it is possible to provide a portable terminal that exhibits superior communication performance within a communicable area while the communicable area is being expanded by utilization of the enclosures.

0017Further, the antenna is provided within the enclosures, and a circuit board provided within the enclosures is used as a metallic body. It thereby becomes possible to provide a portable terminal that exhibits superior communication performance within a communicable area while the communicable area is being expanded by utilization of the circuit board of the portable terminal.

0018Embodiments of the present disclosure are hereunder described by reference to the drawings.

(First Embodiment)

0019<figref idref="f0001">Fig. 1</figref> is an oblique perspective view of an antenna of a first embodiment; <figref idref="f0001">Fig. 2</figref> is a top view of the antenna of the first embodiment; and <figref idref="f0002">Fig. 3</figref> is a side view of the antenna of the first embodiment. <figref idref="f0002">Fig. 3</figref> is a cross sectional view taken along line A-A' shown in <figref idref="f0001">Fig. 2</figref>.

0020The antenna 1 shown in <figref idref="f0001">Fig. 1</figref> includes a loop antenna pattern 3 laid on an antenna board 2. In <figref idref="f0001">Fig. 1</figref>, the antenna pattern 3 exemplifies a three-turn antenna. However, the antenna pattern is not limited to three turns.

0021In order to lessen influence generated when metal is placed on the antenna, a magnetic sheet 4 is placed on the antenna pattern 3.

0022The antenna pattern 3 is connected to an input-output terminal of a matching circuit and an input-output terminal of an IC by means of input-output terminals 5 and 6.

0023A metallic body 7 is provided with a notch 8 that is formed so as to connect with a periphery of the metallic body 7 and that assumes a rectangular shape matching the shape of the antenna. The metallic body 7 is formed into the shape of the letter C by means of the notch 8.

0024Specifically, the notch 8 is not formed so as to make a hole in the metallic body 7 but assumes a shape cut out of the periphery of the metallic body 7.

0025The antenna board 2 and the antenna pattern 3 are positioned, while substantially adjoining the metallic body 7, so as to cover the notch 8 of the metallic body 7, and the metallic body 7, the antenna board 2, the antenna pattern 3, and the magnetic sheet 4 are stacked in sequence.

0026Detailed descriptions are provided to the shape of the antenna pattern 3 and the shape of the notch 8 by reference primarily to <figref idref="f0001">Figs. 2</figref> and <figref idref="f0002">3</figref>.

0027As is clear from the drawings, the notch 8 is smaller than an outer shape of the antenna pattern 3 (the outermost loop of the antenna pattern 3), and the notch is also formed so as to extend along an aperture (the innermost loop of the antenna pattern 3) of the antenna pattern 3.

0028Specifically, the notch 8 is made substantially equal in size to the aperture of the antenna pattern 3.

0029The aperture of the antenna pattern 3 is arranged so as to match the notch 8. As shown in <figref idref="f0001">Fig. 2</figref>, the antenna pattern 3 is arranged in line with a side of the metallic body 7 where the notch 8 is formed.

0030As shown in <figref idref="f0002">Fig. 3</figref>, the antenna pattern 3 is laid on the metallic body 7 by way of the antenna board 2.

0031The configuration mentioned above makes it possible to efficiently utilize an electric current developing in the metallic body 7, which will be described later.

0032In the present embodiment, the notch 8 is placed so as to situate at the center of the side where the notch is to be formed.

0033A configuration of the antenna 1 is hereunder described.

0034First, the antenna board 2 is described. The antenna board 2 is a base board on which electronic members, like the antenna pattern 3, the input-output terminals 5 and 6, and others, are to be mounted. In the present embodiment, the base board is a substrate that exhibits an insulation property. The base board can be formed from; for instance, polyimide, PET, a glass epoxy substrate, or the like.

0035The antenna pattern 3 is now described. The antenna pattern 3 is formed in a spiral shape. A spiral structure is a spiral shape having an aperture in its center. The spiral structure can assume either a circular shape, a substantial rectangular shape, or a polygonal shape typified by a triangular shape and a square shape. Moreover, the antenna pattern 3 may also be placed in one plane or stacked. By adoption of a spiral structure, a magnetic field developing from a reader/writer is caused to effect inter-linkage with the aperture, to thus induce electric power, and it becomes possible to transmit an electric signal to a matching circuit connected to the input-output terminals 5, 6 and an IC chip and to establish communication with the reader/writer. Any material is used as a material for the pattern, so long as the material exhibits electrical conductivity. The material is selected as appropriate from a conductive metallic wire, a metallic plate material, a metallic foil material, and a metallic sleeve material, like gold, silver, copper, aluminum, and nickel. The pattern can be formed from a metallic wire, a metallic foil, a conductive paste, transfer plating, sputtering, deposition, or screen printing.

0036The magnetic sheet 4 is now described. The magnetic sheet 4 is placed on the antenna pattern 3 and may assume any of a circular shape, a substantially rectangular shape, or a polygonal shape typified by a triangular shape or a square shape. The magnetic sheet 4 is intended for lessening influence which arises when the metallic body is placed on the magnetic sheet 4. It is desirable that the magnetic sheet 4 shall completely cover the antenna pattern 3. So long as the magnetic sheet covers the antenna pattern 3, the magnetic sheet may be larger than the antenna pattern 3. For instance, the magnetic sheet may also be equal in size to the metallic body 7.

0037Further, either an insulating magnetic material like ferrite or a conductive magnetic material like an electromagnetic steel plate can also be employed as a material for the magnetic body.

0038The input-output terminals 5 and 6 are now described. The input-output terminals 5 and 6 are electrically connected to the antenna pattern 3. Any material is available, so long as the material exhibits conductivity. The material can be selected as appropriate from a conductive metallic wire, a metallic plate material, a metallic foil material, and a metallic sleeve material, like gold, silver, copper, aluminum, and nickel. The input-output terminals can be formed from a metallic wire, a metallic foil, a conductive paste, transfer plating, sputtering, deposition, or screen printing. The input-output terminals 5 and 6 are electrically connected to a matching circuit and an IC chip. There can be selected a commonly utilized connection technique, such as pin connection, spring connection, soldering, connector connection, and the like.

0039Any material is used as a material for the input-output terminals, so long as the material exhibits electrical conductivity. The material is selected as appropriate from a conductive metallic foil material and a metallic plate material, like gold, silver, copper, aluminum, and nickel. The input-output terminals can be formed from a metallic foil, a conductive paste, transfer plating, sputtering, deposition, or screen printing.

0040A concept of operation of the antenna of the present embodiment is now described by reference to <figref idref="f0002">Figs. 4</figref> and <figref idref="f0003">5</figref>.

0041<figref idref="f0002">Fig. 4</figref> is a conceptual rendering of the result achieved when transmission is performed by means of the antenna. By virtue of signals entering the input-output terminals 5 and 6, an electric current 9 flows into the antenna pattern 3 from an external circuit, whereby a magnetic field 10 develops. An eddy current 11 develops in the metallic body 7 in a direction cancelling the magnetic field 10. As a result of the notch 8 being provided in the metallic body 7 so as to run along the aperture of the antenna pattern 3, the eddy current 11 eventually flows through three sides of the notch in a direction opposite to the electric current 9 flowing through the antenna pattern 3. However, the eddy current 11 flowing through a portion of the metallic body 7 other than the notch 8 is directed in a forward direction with respect to the electric current 9 flowing through the antenna pattern 3. Therefore, the antenna pattern apparently becomes greater, and a degree of coupling with a card that will be on the other end of communication becomes stronger, as a consequence of which communication performance is enhanced. <figref idref="f0003">Fig. 5</figref> is a conceptual rendering of the result achieved when the antenna receives a magnetic field from the outside. An eddy current 13 flows along the periphery of the metallic body 7 by means of a magnetic field 12 from the outside, and a magnetic field 14 develops in the periphery of the metallic body 7 because of the eddy current 13. The notch 8 is provided on the metallic body 7 so as to be aligned with the aperture of the antenna pattern 3, whereby the magnetic field 14, such as that shown in <figref idref="f0003">Fig. 5</figref>, develops in the outer periphery of three sides of the notch 8, and hence a downward magnetic field 15, such as that shown in <figref idref="f0003">Fig. 5</figref>, develops in an inner periphery of the antenna pattern 3. Although an eddy current 16 develops in the antenna pattern 3 in a direction cancelling the magnetic field 15 at this time, the eddy current 16 is oriented in a forward direction with respect to the eddy current 13 flowing through the periphery of the metallic body 7. Therefore, the antenna pattern apparently becomes greater, and the antenna becomes possible to receive a greater quantity of magnetic field originating from the reader/writer that is to be on the other side of communication. As a result, communication performance is enhanced. <figref idref="f0004">Fig. 6</figref> shows a test result yielded when the antenna 1 of the present embodiment is compared with an antenna that does not use the metallic body 7. Measurement conditions are as follows. First, the antenna 1 of the present embodiment is placed upside down, and input impedance of the input-output terminals 5 and 6 is matched to 50Ω by way of a matching circuit. Subsequently, a signal of 20 dBm is input from a signal generator. The metallic body 7 measures 62 mm x 38 mm, and an outer shape of the antenna pattern 3 measures 20 mm x 20 mm.

0042A one-turn search coil measuring 72 mm x 42 mm is placed above the antenna 1, and both ends of the search coil are connected to observation terminals of an oscilloscope, thereby carrying out observations at a port impedance of 1 MΩ. The magnetic field developed from the antenna 1 performs cross linkage with respect to the search coil, whereupon an induced voltage occurs at both ends of the search coil. The induced voltage is observed by means of the oscilloscope. The search coil is disposed in such a way that a center of the metallic body 7 of the antenna 1 faces up to a center of the search coil.

0043When the metallic body 7 is not used, the center of the antenna pattern 3 is arranged so as to face up to the center of the search coil. A horizontal axis shown in <figref idref="f0004">Fig. 6</figref> represents a distance between the antenna 1 and the search coil, whilst a vertical axis of the same drawing represents a peak-to-peak voltage of a voltage waveform observed by the oscilloscope. The graph shown in <figref idref="f0004">Fig. 6</figref> shows that, when compared with an antenna that does not use the metallic body 7, the antenna 1 of the present embodiment can cause a greater induced voltage, and it is possible to ascertain a greater effect particularly within a neighborhood of 20 mm. <figref idref="f0005">Fig. 7</figref> is an exploded perspective view of an example portable terminal using the antenna of the first embodiment (a portable phone in the example). A portable terminal 18 is built from a liquid crystal panel 19, buttons 20, and a board 21 and a battery 22 encapsulated between enclosures 23 and 24. The antenna 1 is attached to the enclosure 24. The antenna 1 is attached to the other side of the board 21 where the liquid crystal panel 19 is not disposed. The metallic body 7 is attached to the enclosure 24, and the antenna pattern 3 and the magnetic sheet 4 are piled on the enclosure 24.

0044Although the metallic body 7 does not need to be attached to the enclosure 24, it is expected that the characteristic of the antenna will be deteriorated when metallic components mounted on the metallic body 7 and metallic components mounted on the board 21 approach each other. Therefore, it may be appropriate to keep the metallic components mounted on the metallic body as far away as possible from the metallic components mounted on the board 21.

0045The enclosure 24 and the metallic body 7 can also be integrated together. Any material may be employed for the enclosure 24 in the case, so long as the material exhibits conductivity in the same manner as does the metallic body 7. The material is selected as appropriate from a conductive metallic plate material, and a conductive metallic foil material, like gold, silver, copper, aluminum, and nickel. The enclosure can be formed from a metallic foil, a conductive paste, transfer plating, sputtering, deposition, or screen printing.

0046The board 21 can also be used in place of the metallic body 7. In such a case, the antenna is disposed on the other side of the board 21 where the liquid crystal panel is not disposed. From the structural viewpoint, the magnetic sheet 4 and the antenna pattern 3 are provided on the underside of the board 21 in sequence from the board.

0047Moreover, in the present embodiment, the metallic body 7 is formed from a metallic foil, or the like. Therefore, for instance, a notch is formed in the metallic body 7 in accordance with a layout of components in a portable terminal into which the antenna is to be incorporated, such as a camera, so that the metallic body can be arranged so as to avoid the layout of the components.

0048A foldable material, such as a metallic foil, is utilized for the metallic body 7 as mentioned above, or the metallic body is formed directly on a curved surface of an enclosure by means of sputtering, or the like. Thus, the metallic body 7 can be placed along the curved surface of the enclosure. Thus, as compared with a related art antenna that cannot be disposed on a curved surface, the antenna can be freely designed.

(Second Embodiment)

0049<figref idref="f0006">Fig. 8</figref> is an oblique perspective view of the antenna 1 of a second embodiment. <figref idref="f0006">Fig. 9</figref> is a plan view of the antenna of the second embodiment. <figref idref="f0007">Fig. 10</figref> is a side view of the antenna of the second embodiment.

0050In the antenna 1 shown in <figref idref="f0006">Fig. 8</figref>, the loop-shaped antenna pattern 3 is formed on the antenna board 2. <figref idref="f0006">Fig. 8</figref> illustrates a case where the antenna pattern 3 has three turns. However, the number of turns of the antenna pattern is not limited to three. In order to lessen influence generated when metal is placed on the antenna, the magnetic sheet 4 is placed on the antenna pattern 3. The antenna pattern 3 is connected to an input-output terminal of a matching circuit and an input-output terminal of an IC by means of the input-output terminals 5 and 6. The metallic body 7 is positioned substantially in contact with the antenna board. The notch 8 of the metallic body 7 is cut out along the aperture of the antenna pattern 3 achieved when the antenna pattern 3 is placed at a center of the metallic body 7. The metallic body 7 is laid out in a geometry in which a slit 17 is formed so as to extend from one side of the notch 8 to an opposing side of the metallic body 7. The configuration of the antenna 1 is analogous to the first embodiment.

0051A concept of operation of the antenna of the present embodiment is now described by reference to <figref idref="f0007">Figs. 11</figref> and <figref idref="f0008">12</figref>.

0052<figref idref="f0007">Fig. 11</figref> is a conceptual rendering of the result achieved when transmission is performed by means of the antenna. By virtue of the signals entered the input-output terminals 5 and 6 from the outside circuit, the electric current 9 flows into the antenna pattern 3, whereby the magnetic field 10 develops. Although the eddy current 11 develops in the metallic body 7 in a direction cancelling the magnetic field 10, the notch 8 and the slit 17 are provided in the metallic body 7 in such a way that the notch 8 runs along the aperture of the antenna pattern 3 and that the slit 17 extends from one side of the notch 8 to the periphery of the metallic body 7. As a result, the eddy current 11 that is oriented in a direction opposite to the electric current 9 flowing through the antenna pattern 3 flows through the respective sides of the notch. However, the eddy current 11 flowing through the respective sides of the notch are guided to the periphery of the metallic body 7 by the slit 17. Therefore, the eddy current 11 flowing through the periphery of the metallic body 7 is oriented in a forward direction with respect to the electric current 9 flowing through the antenna pattern 3. For these reasons, the antenna pattern apparently becomes larger, so that a degree of coupling with a card that is on the other end of communication becomes greater. As a consequence, communication performance is enhanced.

0053<figref idref="f0008">Fig. 12</figref> is a conceptual rendering of the result achieved when the antenna receives a magnetic field from the outside. By virtue of the magnetic field 12 from the outside, the eddy current 13 flows along the periphery of the metallic body 7, and the eddy current 13 causes the magnetic field 14 to develop in the periphery of the metallic body 7. The notch 8 and the slit 17 are provided in the metallic body 7 in such a way that the notch 8 runs along the aperture of the antenna pattern 3 and that the slit 17 extends from one side of the notch 8 to the periphery of the metallic body 7. As a result, the magnetic field 14, such as that shown in <figref idref="f0008">Fig. 12</figref>, develops in the periphery made up of the respective sides of the notch 8. Consequently, the downwardly oriented magnetic field 15, such as that shown in <figref idref="f0008">Fig. 12</figref>, develops in an inner periphery of the antenna pattern 3. The eddy current 16 develops in the antenna pattern 3 in a direction cancelling the magnetic field 15. However, the eddy current 16 is oriented in a forward direction with respect to the eddy current 13 flowing through the periphery of the metallic body 7. For these reasons, the antenna pattern apparently becomes larger, to thus become possible to receive a larger amount of magnetic field emitted from the reader/writer that becomes the other end of communication. As a consequence, communication performance is enhanced.

0054<figref idref="f0009">Fig. 13</figref> is a test result achieved when the antenna 1 of the present embodiment is compared with an antenna that does not use the metallic body 7. Measurement conditions are analogous to those described in connection with the first embodiment. According to a graph shown in <figref idref="f0009">Fig. 13</figref>, the antenna 1 of the present embodiment can produce a greater induced voltage than does the antenna that does not use the metallic body 7. A greater effect can be ascertained particularly within a neighborhood of 20 mm.

0055<figref idref="f0010">Fig. 14</figref> is an exploded oblique view of an example portable terminal using the antenna of the second embodiment. The portable terminal 18 and the antenna 1 are structurally analogous to their counterparts described in connection with the first embodiment. It is desirable that the antenna pattern 3 be placed at the center of the metallic body 7. Even in this case, the metallic body 7 does not need to be affixed to the enclosure 24. However, it is expected that when metallic components mounted on the metallic body 7 and metallic components mounted on the board 21 come close to each other, a characteristic of the antenna is deteriorated. For this reason, it may be appropriate to keep the metallic components mounted on the metallic body 7 as far away as possible from the metallic components mounted on the board 21.

0056In <figref idref="f0001">Fig. 1</figref>, the notch 8 is formed so as to run along three sides of the aperture of the antenna pattern 3. However, the notch 8 may also be formed so as to run along two sides of the aperture of the antenna pattern 3.

0057<figref idref="f0011">Fig. 15</figref> shows a test result of a comparison between the antenna 1 including the notch 8 of the metallic body 7 that is aligned with two sides of the aperture of the antenna pattern 3 and the antenna that does not use the metallic body 7. According to the graph shown in <figref idref="f0011">Fig. 15</figref>, even when the notch is aligned with two sides of the aperture of the antenna pattern 3, the antenna 1 of the present embodiment can produce a greater induced voltage than does the antenna that does not use the metallic body 7.

0058As mentioned above, the antenna of the present disclosure includes the followings; namely, a loop antenna having an aperture, a metallic body that opposes the loop antenna and that is electrically insulated from the loop antenna; and a notch that is provided in the metallic body and that is coupled with the periphery of the metallic body. At least a portion of the loop antenna opposes the metallic body, and at least a portion of the notch is covered with the aperture. An air field in a communicable area is reduced while the communicable area is being expanded. Therefore, it is possible to provide an antenna that exhibits superior communication performance within the communicable area.

0059As a result of the metallic body being disposed on the side where the aperture of the loop antenna exits, an eddy current flowing through the metallic body becomes likely to develop, and much superior communication performance can be exhibited within the communicable area.

0060An outer shape of the loop antenna is smaller than the metallic body, and the notch is smaller than the outer shape of the loop antenna, so that the loop antenna thoroughly faces the metallic body. Hence, much superior communication performance can be exhibited within the communicable area.

0061The aperture of the loop antenna is placed on the metallic body so as to cover the entirety of the notch. As a result, the loop antenna thoroughly opposes the metallic body within the greatest area, and hence highly superior communication performance can be exhibited within the communicable area.

0062Since the notch is substantially equal in size with the aperture of the loop antenna, the loop antenna thoroughly opposes the metallic body, so that the magnetic field passing through the aperture is not blocked by the metallic body. Accordingly, the loop antenna thoroughly opposes the metallic body within the greatest area, and hence highly superior communication performance can be exhibited within the communicable area.

0063The entirety of an end that is an end of the metallic body and that makes up the notch opposes the loop antenna. As a result, the loop antenna opposes the metallic body without fail in the greatest area, and hence very excellent communication performance can be exhibited within the communicable area.

0064The metallic body includes the notch covered with the aperture of the loop antenna, an opposite direction current generation block that opposes the loop antenna, and a non-opposing block that does not opposes the antenna. As a result, the communicable area can be expanded without fail. Since the air field in the communicable area is reduced, there can be provided an antenna that efficiently exhibits superior communication performance within the communicable area. Further, an electric current flowing through the opposite direction current generation block is opposite in direction to an electric current flowing through the loop antenna. An electric current flowing through the non-opposing block is identical in direction with the electric current flowing through the loop antenna. The communicable area is thereby expanded without fail. Moreover, since the air field in the communicable area is reduced, there can be provided an antenna that efficiently exhibits superior communication performance within the communicable area.

0065A magnetic field caused by the electric current flowing through the opposite direction current generation block is opposite in direction to a magnetic field caused by the electric current flowing through the loop antenna. A magnetic field caused by the electric current flowing through the non-opposing block is identical in direction to the magnetic field caused by the electric current flowing through the loop antenna. The communicable area can thereby be expanded reliably. Further, the air field in the communicable area is reduced, and hence there can be provided an electronic device that efficiently exhibits superior communication performance within the communicable area.

0066The entire aperture of the loop antenna is situated within the notch, whereby a magnetic field passing through the aperture is not blocked by the metallic body. Accordingly, the loop antenna thoroughly opposes the metallic body within the largest area, and hence much superior communication performance can be exhibited within the communicable area.

0067The antenna of the present disclosure can be provided comprising the following; namely, a loop antenna having an aperture, a metallic body that is electrically insulated from the loop antenna and that is placed on a side where the aperture of the loop antenna is provided; and a notch that is smaller than the outer shape of the loop antenna, that is provided in the metallic body, and that is coupled with a periphery of the metallic body. The loop antenna is placed on the metallic body so as to cover the notch. The air field within the communicable area is thereby reduced while the communicable area is being expanded, and hence there can be provided an antenna that exhibits superior communication performance within a communicable area.

0068Further, as a result of the antenna being disposed in the enclosures and the metallic body being provided on the back side of the enclosure, the air field within the communicable area is reduced while the communicable area is being expanded. Hence, there can be provided an antenna that exhibits superior communication performance within the communicable area.

0069The antenna is disposed within the enclosures, and a circuit board disposed within the enclosures is used as a metallic body. The air field within the communicable area is thereby reduced while the communicable area is being expanded, and hence there can be provided an electronic device that exhibits superior communication performance within the communicable area. Further, further miniaturization of the antenna can be pursued.

0070The antenna of the present disclosure and the portable terminal using the same exhibit superior communication performance within a communicable area while expanding the communicable area and hence are useful for an electronic device, like a portable phone.

0071This application claims the benefit of Japanese Patent application No. <patcit id="pcit0002" dnum="JP2010060617A"><text>2010-060617 filed on March 17, 2010</text></patcit>, the entire contents of which are incorporated herein by reference.