JP2007088849A - Antenna element and electronic equipment using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna element without a sense of incongruity in design even when it is used for thin electronic equipment and which can be stored in the electronic equipment when it is not used. <P>SOLUTION: The antenna element is flat whose outline has the shape of approximate equilateral triangle and whose vertical angle part is a feeding point 14. The antenna element 12 is constituted so that a conducting part 13 for grounding and the feeding point 14 are electrically connected and the bottom side is located upward at a use state. Projected parts 12a provided at intervals and notched parts 12b provided between the projected parts 12a are formed on two sides sandwiching the feeding point 14. Thus, since travel (creeping distance) of current which flows from the feeding point 14 of the antenna 12 is lengthened by forming the projected parts 12a and the notched parts 12b on the two sides sandwiching the feeding point 14, the antenna element with low cut off frequency even if it is small is attained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antenna element suitable for use in an electronic device having a function of receiving radio waves, such as a personal computer.

An antenna element disclosed in Japanese Patent Application Laid-Open No. 11-355031 is known as an antenna element that is broadband and small and can be easily placed in a roof ridge. The antenna element 1 has a substantially horn shape. The antenna element 1 is arranged so that its central axis is substantially vertical and the apex of the horn is located on the ground plate 2 side. In addition, a capacitor 3 is arranged at a predetermined interval on the peripheral edge of the bottom surface of the antenna element 1. One end of the capacitor 3 is coupled to the ground plate 2.
Japanese Patent Laid-Open No. 11-355031

  However, since the antenna element as described above has a three-dimensional shape, it cannot be stored in a thin electronic device such as a notebook personal computer. In addition, since the size of the antenna element is relatively large, about one-sixth of the radio wave wavelength, when it is mounted on the thin electronic device, the ratio of the antenna element to the electronic device increases, which is unbalanced in design. is there.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an antenna element that is not uncomfortable in design even when used in a thin electronic device and can be stored in the electronic device when not in use. .

  The antenna element of the present invention has a substantially isosceles triangular shape, and is provided on a flat antenna body having a feeding point at the apex position of the isosceles triangle, on two sides sandwiching the feeding point. And a cut portion provided between the protrusions.

  According to this configuration, since the protruding portion and the cut portion are formed on the two sides sandwiching the feeding point, it is possible to lengthen the stroke (creeping distance) of the current flowing from the feeding point of the antenna element, and the size is small. However, an antenna element having a low cutoff frequency can be realized.

  In the antenna element according to the aspect of the invention, it is preferable that the protruding portion and the cut portion extend in a direction orthogonal to each of the two sides. According to this configuration, the planar shape of the protruding portion and the cut portion can be substantially rectangular. As a result, the current flowing along the two sides flows along the projecting portion and the notched portion without flowing as a shortcut, so that the current stroke can be lengthened more efficiently.

  In the antenna element of the present invention, it is preferable that the protruding portion and the cut portion are rotationally symmetric with respect to the feeding point. According to this configuration, since the projecting portion and the cut portion are rotationally symmetric about the feeding point, the antenna element has a self-complementary shape, and an antenna element that can handle a wide band can be realized. it can.

  In the antenna element of the present invention, it is preferable that an angle formed by an imaginary line connecting the ends of the protruding portions on each side is 120 ° to 150 °. According to this configuration, it is possible to efficiently increase the creepage distance while keeping the prototype of the antenna element in a substantially isosceles triangle.

  The electronic device of the present invention can be stored in an electronic device main body having a grounding conductive portion and the electronic device main body, and is arranged such that the feeding point is electrically connected to the grounding conductive portion in use. And the above antenna element.

  According to this configuration, since the antenna element can be stored in the electronic device main body, the antenna element is sufficiently small with respect to the electronic device main body. Therefore, there is no sense of incongruity even when the antenna element is used, and the design is not affected.

  The antenna element according to the present invention has a substantially isosceles triangular shape, and is provided on a flat antenna body having a feeding point at the apex position of the isosceles triangle, on two sides sandwiching the feeding point. Because it has a protruding part and a notch provided between the protruding parts, it does not feel uncomfortable in design even when used in thin electronic devices, and can be stored in electronic devices when not in use. It is a thing. Further, the antenna element of the present invention can be miniaturized, and even if it is small, an antenna element having a low cutoff frequency can be realized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a perspective view showing a schematic configuration of an electronic apparatus including an antenna element according to an embodiment of the present invention. A notebook personal computer 1 that is an electronic device includes a device main body 11, an antenna element 12 that can be stored in the device main body, and a grounding provided along the outer peripheral portion of the back surface of the device main body 11. And a conductive portion (ground) 13. The height H of the antenna element 12 is about 1/10 of the wavelength of the lower cutoff frequency. Here, since the cutoff frequency on the lower side is 470 MHz, the height of the antenna element 12 is 6.4 cm, which is 1/10 of the wavelength 64 cm.

  The personal computer 1 has functions that are normally installed, but a description thereof is omitted. The antenna element 12 can be stored in the apparatus main body 11. Further, when the antenna element 12 is in use, the bottom side is disposed above, the feeding point (vertical angle portion of the antenna element shape described later) is disposed below, and the feeding point is electrically connected to the grounding conductive portion 13. Connected. In addition, there is no restriction | limiting in particular as a method of accommodating the antenna element 12 in the apparatus main body 11, For example, the feeding point part of the antenna element 12 is rotatably attached to the apparatus main body 11, and the antenna element 12 is rotated. The power supply point portion of the antenna element 12 may be slidably attached to the apparatus main body 11, and the antenna element 12 may be slid to be in the use state and the storage state. . Alternatively, the antenna element 12 is configured to be detachable from the apparatus main body 11, and the antenna element 12 is attached to the apparatus main body 11 when in use, and the antenna element 12 is detached from the apparatus main body 11 when stored. It may be stored.

  In the present embodiment, the grounding conductive portion 13 is provided along the outer peripheral portion of the back surface of the apparatus main body 11, but is not limited thereto, and may be provided on the entire back surface. As the grounding conductive portion 13, a foil, a sheet, a film, or the like made of a conductive material such as metal can be used. For example, the grounding conductive portion 13 needs to be sufficiently large with respect to the antenna element 12 in order to exhibit stable antenna characteristics even when touched by the user. Since the antenna element according to the present invention is sufficiently small with respect to the device main body to be mounted, if the grounding conductive portion 13 is provided along the outer peripheral portion of the device main body, the grounding conductive portion 13 with respect to the antenna element 12 is provided. Can be provided sufficiently large. Specifically, the size (area, etc.) of the grounding conductive portion 13 is preferably about three times or more the size (area, etc.) of the antenna element 12.

  In such an electronic device, since the antenna element 12 can be stored in the apparatus main body 11, the antenna element 12 is sufficiently small with respect to the apparatus main body 11. Therefore, there is no sense of incongruity even when the antenna element 12 is used, and the design is not affected.

  FIG. 2 is a diagram for explaining the antenna element 12 in the electronic apparatus shown in FIG. The antenna element 12 has a flat plate shape whose outer shape has a substantially isosceles triangle shape, and the apex portion serves as a feeding point 14. The feeding point 14 may not be the apex angle portion, and may be provided between the grounding conductive portion 13 and the apex angle portion. When the antenna element 12 is in use, the grounding conductive portion 13 and the feeding point 14 are electrically connected so that the bottom side is located above (the bottom side and the upper end portion of the grounding conductive portion 13 are connected to each other). Almost parallel). In addition, the apex angle of the antenna element 12 is preferably about 90 ° in consideration of antenna characteristics.

  On two sides (slanted sides) sandwiching the feeding point 14, a protruding portion 12a provided at an interval and a cut portion 12b provided between the protruding portions 12a are formed. That is, the protruding portions 12a and the cut portions 12b are alternately formed on each side. By forming the protrusion 12a and the notch 12b on the two sides sandwiching the feeding point 14 in this way, it is possible to lengthen the stroke (creeping distance) of the current flowing from the feeding point 14 of the antenna element 12, so that the small size Even so, an antenna element having a low cutoff frequency can be realized. The protrusion 12a and the notch 12b are preferably rotationally symmetric about the feeding point 14. As described above, the projecting portion 12a and the cut portion 12b are rotationally symmetric with respect to the feeding point 14, so that the antenna element 12 has a self-complementary shape, and an antenna element capable of supporting a wide band is realized. be able to.

  In order to make the antenna element have the same impedance over a wide band, it is necessary that the length of the antenna element is sufficient for radio waves having a long wavelength. In order to increase the length of the antenna element, the length of the two sides sandwiching the feeding point in the antenna element may be increased. However, simply increasing the length of the two sides increases the size of the antenna element itself. In the antenna element of the present invention, the shape of the antenna element 12 is a shape having an isosceles triangle as a prototype even if the projecting portion 12a and the cut portion 12b are provided on the two sides. Not long. For this reason, the cutoff frequency can be lowered. Further, in the antenna element of the present invention, since the protruding portion 12a and the cut portion 12b are provided on the two sides, a detour for the current flowing from the feeding point 14 can be made, and the current stroke (creeping distance) becomes long. . Therefore, the antenna element 12 has a sufficient length for radio waves having a relatively long wavelength. Therefore, impedance matching can be performed for radio waves having a relatively long wavelength, that is, radio waves on the lower frequency band side.

  The protruding portion 12a and the cut portion 12b formed on the two sides sandwiching the feeding point 14 extend in a direction perpendicular to the respective sides of the two sides. As described above, the projecting portions 12a and the cut portions 12b extend in directions orthogonal to the respective sides, whereby the planar shapes of the projecting portions 12a and the cut portions 12b can be made substantially rectangular. As a result, the current flowing through the two sides flows along the projecting portion 12a and the cut portion 12b without flowing as a shortcut, so that the current stroke can be lengthened more efficiently.

  If the width (W) of the protruding portion 12a or the width of the cut portion 12b is too narrow, the current flowing through the two sides flows as a shortcut, and a sufficient creepage distance cannot be obtained. On the other hand, if the protruding length of the protruding portion 12a or the cutting depth of the cut portion 12b is too large, the antenna element 12 is not an isosceles triangle and the antenna characteristics are deteriorated. On the other hand, since the impedance increases as the creepage distance becomes relatively long, it is preferable to gradually increase the width (W) of the protruding portion 12a and / or the width of the cut portion 12b as the distance from the feeding point 14 increases. Further, it is not preferable to increase the width (W) of the protruding portion 12a and / or the width of the cut portion 12b more than necessary in order to increase the creepage distance. Therefore, when the distance from the feeding point 14 on the oblique side is L and the width of the protrusion 12a is W, the relationship between W / L and L is a substantially logarithmic straight line relationship as shown in FIG. It is preferable that

Further, the virtual line connecting the ends of the projections 12a in each side (hypotenuse) angle formed (dashed lines in FIG. 2) (theta _3), that is, from 180 ° to the imaginary line from the end portion of the ground conductor 13 The angle obtained by subtracting the angle (θ ₁ ) is preferably 120 ° to 150 °. By setting in this way, it is possible to efficiently increase the creepage distance while keeping the prototype of the antenna element 12 in a substantially isosceles triangle. The angle θ ₂ is an angle from the end of the grounding conductive portion 13 to the oblique side of the antenna element 12.

  As shown in FIG. 1 in which the antenna element 12 having such a configuration is mounted, the SWR (Standing Wave Ratio) of the notebook personal computer 1 was examined over a frequency range of 470 MHz to 770 MHz. The result is shown in FIG. The antenna height H was set to 6.4 cm, which is 1/10 of the wavelength of 470 MHz radio wave of 64 cm. SWR was measured using ADVANTEST NETWORK ANALYZER R3767CG (trade name, manufactured by Advantest). As can be seen from FIG. 4, the antenna element 12 according to the present invention exhibited a sufficient antenna characteristic over a wide band despite having a small SWR of 3 or less for a characteristic impedance of 50Ω at a frequency of 470 MHz to 770 MHz. .

  As described above, since the antenna element according to the present invention has the protruding portion and the cut portion formed on the two sides sandwiching the feeding point, the stroke of the current (creeping distance) flowing from the feeding point of the antenna element is increased. An antenna element having a low cutoff frequency can be realized even if it is small. Further, in the electronic apparatus equipped with the antenna element of the present invention, the antenna element 12 can be stored in the apparatus main body 11, so that the antenna element 12 is sufficiently small with respect to the apparatus main body 11. Therefore, there is no sense of incongruity even when the antenna element 12 is used, and the design is not affected.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. For example, the numerical values, forms, dimensions, and materials described in the above embodiments are not limited to these, and can be appropriately changed without departing from the scope of the present invention.

  The antenna element of the present invention can be applied to an electronic device having a function of receiving radio waves such as a personal computer.

It is a perspective view which shows schematic structure of the electronic device provided with the antenna element which concerns on one embodiment of this invention. It is a figure for demonstrating the antenna element in the electronic device shown in FIG. It is a characteristic view for demonstrating the appropriate magnitude | size of a protrusion part and a notch part. It is a characteristic view which shows the relationship between SWR and a frequency. It is a figure which shows schematic structure of the conventional antenna element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Personal computer 11 Computer main body 12 Antenna element 12a Protrusion part 12b Cut part 13 Conductive part for earthing 14 Feeding point

Claims (5)

  The outer shape is a substantially isosceles triangle, a flat antenna body having a feeding point at the apex position of the isosceles triangle, a protrusion provided at an interval on two sides sandwiching the feeding point, and An antenna element comprising: a notch portion provided between the projecting portions.   2. The antenna element according to claim 1, wherein the protruding portion and the cut portion extend in a direction orthogonal to each of the two sides.   The antenna element according to claim 1, wherein the protruding portion and the cut portion are rotationally symmetric about the feeding point.   The antenna element according to any one of claims 1 to 3, wherein an angle formed by an imaginary line connecting the ends of the protrusions on each side is 120 ° to 150 °.   The electronic device main body having a grounding conductive portion, and the electronic device main body can be stored in the electronic device main body, and the power feeding point is disposed so as to be electrically connected to the grounding conductive portion in use. 4. An electronic device comprising the antenna element according to claim 4.

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