JP2011029802A - Dipole antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce effects caused by the arrangement of a feeding cable on the antenna characteristics. <P>SOLUTION: Dipole antennas 101a, 101b respectively include a first radiating element 11 and a second radiating element 12 that are arranged on the same plane. The first radiating element 11 is connected with an internal conductor 31 of a feeding cable 13 at a first feed point P1. The second radiating element 12 is connected with an external conductor 32 of the feeding cable 13 at a second feed point P2. An extended line connecting the first feed point P1 and the second feed point P2 is not overlapped with the second radiating element 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wireless LAN-compatible dual-frequency dipole antenna, and is mainly mounted on an electronic device such as a notebook PC (Personal Computer).

  Conventionally, planar antennas are often used as wireless LAN antennas mounted on electronic devices (see Patent Documents 1 and 2). In the conventional antenna, as shown in FIG. 12, the feeding cable 13 is connected to the radiating element so that the feeding cable overlaps the second radiating element 12.

JP 2004-104333 A JP 2008-160319 A

  When the feeding cable 13 overlaps the second radiating element 112, coupling occurs between the current flowing through the second radiating element 112 and the current flowing through the feeding cable 13. The coupling changes depending on the position. Therefore, conventionally, since the feeding cable 13 overlaps the second radiating element 112, there is a problem that the characteristics of the antenna 91 and the antenna 92 are greatly changed depending on how the feeding cable 13 is routed.

  Therefore, an object of the present invention is to reduce the influence of the arrangement of the feeding cable on the characteristics of the antenna.

  In order to solve the above-described problem, the dipole antenna according to the present invention has the feeding cable connected to the first radiating element and the second radiating element at a position where the feeding cable does not overlap the second radiating element. It is characterized by.

  Specifically, the dipole antenna according to the present invention is a dipole antenna including a first radiating element and a second radiating element arranged on the same plane, and the first radiating element is provided inside the feeding cable. The conductor is connected at the first feeding point, the second radiating element is connected to the outer conductor of the feeding cable at the second feeding point, and the extension connects the first feeding point and the second feeding point. The line is not overlapped with the second radiating element.

  Since the extension line connecting the first feeding point and the second feeding point does not overlap with the second radiating element, it is possible to prevent the feeding cable from being arranged on the second radiating element. Thereby, the change of the coupling between the second radiating element and the feeding cable can be prevented. Therefore, according to the present invention, it is possible to reduce the influence of the arrangement of the feeding cable on the characteristics of the antenna.

  The dipole antenna according to the present invention includes a first radiating element and a second radiating element arranged on the same plane, an internal conductor connected to the first radiating element, and an external conductor connected to the second radiating element. Connected to each other, and a feeding cable that supplies high-frequency power to the first radiating element and the second radiating element, wherein the projected shape of the feeding cable on the same plane is the first It is characterized by not overlapping with the radiating element of 2.

  Since the projection shape of the feeding cable on the same plane does not overlap with the second radiating element, the feeding cable can be prevented from being arranged on the second radiating element. Thereby, the change of the coupling between the second radiating element and the feeding cable can be prevented. Therefore, according to the present invention, it is possible to reduce the influence of the arrangement of the feeding cable on the characteristics of the antenna.

In the dipole antenna according to the present invention, the first radiating element and the second radiating element are arranged at a position closest to each other and substantially perpendicular to an arrangement direction of the first radiating element and the second radiating element. It is preferable that an extending opposing portion is provided, and an end portion of the opposing portion in the first radiating element protrudes in a direction away from the second radiating element.
Impedance matching can be achieved by providing the facing portion. Furthermore, since the edge part of the opposing part protrudes in the direction away from the 2nd radiation | emission element, the length of an opposing part can be shortened. Therefore, an antenna having a small size and excellent input characteristics can be obtained.

  The above inventions can be combined as much as possible.

  ADVANTAGE OF THE INVENTION According to this invention, the influence of arrangement | positioning of the electric power feeding cable with respect to the characteristic of an antenna can be reduced.

It is a structure schematic diagram of the dipole antenna concerning this embodiment, (a) shows the state where a feed cable is not connected, and (b) shows the state where a feed cable is connected. An example of the input characteristic of the dipole antenna which concerns on Embodiment 1 is shown. An example of input characteristics of a dipole antenna with and without a matching element is shown. It is the structure schematic of the dipole antenna which concerns on Embodiment 2, (a) shows the state where the electric power feeding cable is not connected, (b) shows the state where the electric power feeding cable is connected. An example of the input characteristic of the dipole antenna which concerns on Embodiment 2 is shown. The example of mounting to the notebook PC of the dipole antenna which concerns on this embodiment is shown. An example of the input characteristic of the dipole antenna which concerns on Embodiment 3 is shown. An example of the radiation characteristic in 2.4 GHz of the dipole antenna which concerns on Embodiment 3 is shown. An example of the radiation characteristic in 5.2 GHz of the dipole antenna which concerns on Embodiment 3 is shown. An example of the radiation characteristic in 5.725 GHz of the dipole antenna which concerns on Embodiment 3 is shown. An example of the average gain of the dipole antenna which concerns on Embodiment 3 is shown. It is the structure schematic of the conventional antenna. It is the structure schematic of the dipole antenna which concerns on a comparative example. An example of the input characteristic of the dipole antenna which concerns on a comparative example is shown.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a dipole antenna according to the present embodiment, in which (a) shows a state where a feeding cable is not connected, and (b) shows a state where a feeding cable is connected. As shown in FIGS. 1A and 1B, the dipole antenna 101a and the dipole antenna 101b according to the present embodiment include a first radiating element 11 and a second radiating element 12 arranged on the same plane. Is a dipole antenna.

  As shown in FIG. 1 (b), the feed cable 13 has an inner conductor 31 connected to the first radiating element 11, an outer conductor 32 connected to the second radiating element 12, and the first radiating element 11 and High frequency power is supplied to the second radiating element 12. The connection between the first radiating element 11 and the second radiating element 12 is fixed by a conductive material such as solder.

  As shown in FIG. 1A, the first radiating element 11 is connected to the inner conductor 31 of the feeding cable 13 at the first feeding point P1, and the second radiating element 12 is connected to the outer conductor 32 of the feeding cable 13. The extension line connected at the second feeding point P2 and connecting the first feeding point P1 and the second feeding point P2 does not overlap the second radiating element 12. That is, as shown in FIG. 1B, the projection shape of the feeding cable 13 on the same plane where the first radiating element 11 and the second radiating element 12 are arranged overlaps with the second radiating element 12. Don't be.

  Specifically, when the arrangement direction of the first radiating element 11 and the second radiating element 12 is the z-axis direction, the y coordinate of the first feeding point P1 and the second feeding point P2 is the second radiating point. It becomes larger than the element 12. By setting it as such a structure, it can prevent that the electric power feeding cable 13 and the 2nd radiation element 12 overlap. Thereby, the influence on the characteristic of the antenna by the routing of the feeding cable 13 can be reduced.

  In the dipole antenna shown in FIG. 1B, in the state A in which the feeding cable 13 is arranged on the z axis, in the state B in which the feeding cable 13 is bent in the −y direction from the z axis, and the feeding cable The input characteristics of the dipole antenna 101b with respect to the three patterns of the state 13 in which the 13 is bent in the y direction from the z axis were measured. FIG. 2 shows the measurement results of the input characteristics when the height H of the first radiating element 11 and the entire second radiating element 12 is 48 mm and the width W is 8 mm. The distance between the second radiating element 12 and the feeding cable 13 in the state A was 1 mm.

  The same measurement was performed for the comparative example. FIG. 13 shows a schematic configuration diagram of a dipole antenna according to a comparative example. A dipole antenna 103 shown in FIG. 13 does not include the matching element 23 in the dipole antenna 101 b shown in FIG. 1B, and the feeding cable 13 is arranged in the center of the second radiating element 12. FIG. 14 shows the measurement results when the height H of the first radiating element 11 and the second radiating element 12 as a whole is 48 mm and the width W is 8 mm.

  2 and 14, the vertical axis represents VSWR and the horizontal axis represents frequency (GHz). When the broken line is in state A, the thick solid line is in state B, and the thin solid line is in state C. In the state A, the configuration of the dipole antenna according to the present embodiment improves the input characteristics as compared with the comparative example. In the dipole antenna according to the comparative example, the VSWR value did not change in any state. However, in the dipole antenna according to the present embodiment, the feeding cable 13 and the second radiating element 12 as in the state B. As long as there was no overlap, good input characteristics were obtained.

  In the dipole antennas 101a and 101b according to the present embodiment, as shown in FIG. 1A and FIG. 1B, the first radiating element 11 and the second radiating element 12 are arranged at the closest part to each other. It is preferable to have a facing portion extending substantially perpendicular to the arrangement direction of the first radiating element 11 and the second radiating element 12. Thereby, impedance matching can be taken. The first radiating element 11 and the second radiating element 12 are preferably opposed to each other over an appropriate length. For example, the facing portion is preferably equal to or greater than the width W of the first radiating element 11.

  Further, as shown in FIGS. 1A and 1B, the first radiating element 11 preferably has a matching element 23. The matching element 23 is an end portion of the facing portion of the first radiating element 11 and is a portion protruding in a direction away from the second radiating element 12. By having the matching element 23, impedance matching can be achieved without increasing the width in the y-axis direction of the facing portion of the first radiating element 11 and the second radiating element 12. Therefore, a dipole antenna having a narrow width W and excellent input characteristics that can be mounted in a narrow portion can be provided.

  In the dipole antenna shown in FIG. 1B, the input characteristics of the antenna with and without the matching element 23 were measured. FIG. 3 shows the measurement results when the height H of the first radiating element 11 and the second radiating element 12 as a whole is 48 mm and the width W is 8 mm.

  In FIG. 3, the vertical axis represents VSWR, and the horizontal axis represents frequency (GHz). A solid line indicates a case having a matching element, and a broken line indicates a case having no matching element. As shown in FIG. 3, by having the matching element, the VSWR value at a frequency of 3.5 GHz or more and 6 GHz or less was reduced and the input characteristics were improved as compared with the case where the matching element was not provided.

  The dipole antennas 101a and 101b according to the present embodiment are not limited in the shape of the first radiating element 11 and the second radiating element 12, but as shown in FIGS. 1 (a) and 1 (b), It is preferable that a hollow portion 24 in which no conductor is disposed is provided in the central portion of the conductive thin film pattern of the first radiating element 11. Thereby, the current density which flows into the outer edge of the 1st radiation element 11 can be raised. Similarly, the second radiating element 12 is preferably provided with a hollow portion 25 where no conductor is disposed at the center of the conductive thin film pattern of the second radiating element 12.

  Moreover, it is preferable that the 1st radiation element 11 and the 2nd radiation element 12 have a cup shape. In the case of having a cup shape, the width W of the first radiating element 11 is constant over a predetermined length in the z-axis direction from the closest portion of the first radiating element 11 and the second radiating element 12; From there, it spreads out in a circular arc and becomes a constant width again. Since the first radiating element 11 and the second radiating element 12 have a cup shape, even when the width W of the first radiating element 11 is reduced, deterioration of antenna characteristics is prevented. Can do.

(Embodiment 2)
FIG. 4 is a schematic configuration diagram of the dipole antenna according to the present embodiment, in which (a) shows a state where the feeding cable is not connected, and (b) shows a state where the feeding cable is connected. In the dipole antennas 102a and 102b according to the present embodiment, as shown in FIG. 4A, the extension line connecting the first feeding point P1 and the second feeding point P2 does not overlap the second radiating element 12. That is, as shown in FIG. 4B, the projection shape of the feeding cable 13 on the same plane where the first radiating element 11 and the second radiating element 12 are arranged overlaps with the second radiating element 12. It is characterized by not becoming.

  In the dipole antenna shown in FIG. 4B, in the state A in which the feeding cable 13 is arranged on the z axis, in the state B in which the feeding cable 13 is bent in the −y direction from the z axis, and the feeding cable The input characteristics of the antenna were measured for three patterns of 13 in the state C where the 13 was bent in the y direction from the z axis.

  FIG. 5 shows the measurement results when the total height H of the first radiating element 11 and the second radiating element 12 is 48 mm, and the width W of the first radiating element 11 is 8 mm. The width W of the second radiating element 12 was set to 6 mm corresponding to 75% of the width W of the first radiating element 11. The projected shape of the second radiating element 12 onto the yz plane is a shape in which the end in the y direction is removed over a width of 2 mm. Then, 12.5% of the width of the feeding cable 13 is disposed in the portion where the second radiating element 12 is removed. The distance between the second radiating element 12 and the feeding cable 13 in the state A was 1 mm.

  In FIG. 5, the vertical axis represents VSWR, and the horizontal axis represents frequency (GHz). When the broken line is in state A, the thick solid line is in state B, and the thin solid line is in state C. As shown in FIG. 5, the VSWR value does not deteriorate even if a part of the second radiating element 12 is removed. For this reason, it was found that good input characteristics can be obtained as long as the feed cable 13 does not overlap the second radiating element 12. Therefore, the dipole antenna according to the present embodiment can further reduce the width in the y-axis direction while maintaining the input characteristics.

  In addition, as shown in FIG. 4A, when the hollow portion 25 is formed to facilitate the flow of current at the outer edge of the second radiating element 12, it is natural that the loop shape of the hollow portion 25 is formed. So that the end of the second radiating element 12 is removed. For this reason, when the end of the second radiating element 12 is removed, the width of the hollow portion 25 in the y-axis direction is reduced, or the hollow portion 25 is shifted in the −y direction or the z direction, or both of these directions. May be.

(Embodiment 3)
FIG. 6 shows an example of mounting the dipole antenna according to the present embodiment on a notebook PC. Since the dipole antenna 100 according to the present embodiment can be mounted even in a narrow portion, for example, it can be mounted on the LCD 51 (Liquid Crystal Display) of the notebook PC 50.

  In the dipole antenna 100 according to the present embodiment, the first radiating element 11, the second radiating element 12, and the feeding cable 13 can be arranged along the outer edge of the LCD 51. Therefore, the wiring path of the power feeding cable 13 can be a linear path along the outer edge of the LCD 51. Thereby, the notebook PC 50 can be further reduced in thickness.

  Input characteristics, radiation characteristics, and average gain were measured when the dipole antenna 101b shown in FIG. 1B was mounted on the dipole antenna 100 shown in FIG. FIG. 7 shows the measurement results of the input characteristics, FIG. 8 shows the radiation characteristics at 2.4 GHz, FIG. 9 shows the radiation characteristics at 5.2 GHz, FIG. 10 shows the radiation characteristics at 5.725 GHz, and FIG. 11 shows.

  From the measurement results of the input characteristics shown in FIG. 7, it was found that good input characteristics can be obtained in the frequency bands of 2.4 GHz to 2.7 GHz and 4.9 GHz to 5.725 GHz. The frequency band from 2.4 GHz to 2.7 GHz and from 4.9 GHz to 5.725 GHz is a frequency band used by a wireless LAN (Local Area Network) and Bluetooth (registered trademark), and therefore the dipole antenna according to the present embodiment. Can be applied to wireless LAN and Bluetooth (registered trademark).

  The radiation characteristics in FIGS. 8 to 10 indicate a range of −40 dBi to 10 dBi. As shown in FIGS. 8 to 10, the radiation characteristics of the dipole antenna according to this embodiment have a maximum gain of 0 dBi or higher at any frequency of 2.4 GHz, 5.2 GHz, and 5.725 GHz.

  In FIG. 11, the vertical axis represents the average gain (dBi), and the horizontal axis represents the frequency. As shown in FIG. 11, by using the dipole antenna according to this embodiment, an average gain of −5 dBi or more was obtained at any frequency of 2.4 GHz, 5.2 GHz, and 5.725 GHz. Thereby, it was found that the dipole antenna 100 according to the present embodiment can be applied to a wireless LAN and Bluetooth (registered trademark).

  The present invention relates to a wireless LAN-compatible dual-frequency antenna, and is mainly mounted on an electronic device such as a notebook PC, so that it can be used in the information communication industry.

DESCRIPTION OF SYMBOLS 11, 111: 1st radiation element 12, 112: 2nd radiation element 13: Feeding cable 23: Matching element 24, 25: Hollow part 31: Inner conductor 32: Outer conductor 50: Notebook PC
51: LCD
91, 92: antennas 100, 101a, 101b, 102a, 102b, 103: dipole antenna P1: feeding point to the first radiating element P2: feeding point to the second radiating element

Claims (3)

A dipole antenna comprising a first radiating element and a second radiating element arranged on the same plane,
The first radiating element is connected to an inner conductor of a feeding cable at a first feeding point,
The second radiating element is connected to an outer conductor of the feeding cable at a second feeding point,
An extension line connecting the first feeding point and the second feeding point does not overlap the second radiating element. A first radiating element and a second radiating element disposed on the same plane;
An inner conductor is connected to the first radiating element, an outer conductor is connected to the second radiating element, and a feeding cable for supplying high-frequency power to the first radiating element and the second radiating element;
A dipole antenna comprising:
The dipole antenna, wherein a projection shape of the feeding cable on the same plane does not overlap with the second radiating element. The first radiating element and the second radiating element have opposing portions extending in a direction closest to each other and substantially perpendicular to the arrangement direction of the first radiating element and the second radiating element,
3. The dipole antenna according to claim 1, wherein an end of the facing portion of the first radiating element protrudes in a direction away from the second radiating element.

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