JP4889250B2 - Dipole antenna - Google Patents

Description

  The present invention relates to a dipole antenna, and more particularly to a horizontal polarization element used for a polarization diversity antenna of a mobile communication base station and a dipole antenna optimal for a horizontal polarization element of a polarization sharing antenna in which a large number of elements are arranged. About.

FIG. 9 is a perspective view showing a schematic configuration of a conventional dipole antenna.
In the figure, 1 is a reflector, 30 is a half-wave dipole antenna element, and the half-wave dipole antenna element 30 is composed of a pair of radiating elements (13 ₁ , 13 ₂ ).
In the dipole antenna shown in FIG. 9, the pair of radiating elements (13 ₁ , 13 ₂ ) is composed of a metal plate.

However, in the dipole antenna shown in FIG. 9 described above, the half-value width of the directivity characteristic in the horizontal plane is 70 ° to 80 ° from the characteristics of the dipole antenna element 30, and it is not easy to realize a wide-angle beam beyond that. There was a problem.
The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a dipole antenna that can easily realize a wide-angle beam having a half-value width of 90 ° or more in a horizontal plane directivity. It is to provide.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
In order to solve the above-described problems, a dipole antenna according to the present invention includes a reflector, and a first half-wave dipole antenna element and a second half-wave dipole antenna element that are disposed on a reflecting surface of the reflector. In-phase excitation power is supplied to the pair of radiating elements of the first half-wavelength dipole antenna element and the pair of radiating elements of the second half-wavelength dipole antenna element, and the first half-wavelength The pair of radiating elements of the dipole antenna element and the pair of radiating elements of the second half-wave dipole antenna element are inclined with respect to the reflecting surface of the reflector, and the first half-wave dipole antenna element a line connecting the pair of radiating elements, the second and the line connecting the pair of radiating elements of the half wave dipole antenna element intersects, the first half-wave dipole antenna A pair of radiating elements of the child, the distance between the pair of radiating elements of the second half-wave dipole antenna element is characterized in that it increases closer to the reflector.

Also, in the present invention, the reflector, the end portions on both sides in the first direction, bent opposite the first half-wave dipole antenna element and the second half-wavelength dipole antenna element side The first half-wave dipole antenna element has a bent portion, and the first direction is when a pair of radiating elements of the first half-wave dipole antenna element is projected onto a reflecting surface of the reflector. Are parallel to the line connecting the pair of radiating elements.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the present invention, it is possible to easily realize a wide-angle beam dipole antenna having a half-value width of 90 ° or more in the horizontal plane directivity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof is omitted.
FIG. 1 is a schematic perspective view showing a dipole antenna according to an embodiment of the present invention.
In the figure, reference numeral 1 denotes a reflector, and 2 denotes a dielectric substrate. On the dielectric substrate 2, a first half-wave dipole antenna element (hereinafter simply referred to as an antenna element) 31 and a second antenna element 32 are formed.
The first antenna element 31 has a pair of radiating elements (3 ₁ , 3 ₂ ), and the second antenna element 32 has a pair of radiating elements (3 ₃ , 3 ₄ ).
In the present embodiment, the pair of radiating elements (3 ₁ , 3 ₂ ) of the first antenna element 31 and the pair of radiating elements (3 ₃ , 3 ₄ ) of the second antenna element 32 are inclined with respect to the reflecting surface, moreover, a pair of radiating elements of the first antenna element 31 (3 _{1, 3 2)} and a line connecting the pair of the radiating element of the second antenna element 32 (3 _3, The line connecting 3 ₄ ) intersects.

The distance between the pair of radiating elements (3 ₁ , 3 ₂ ) of the first antenna element 31 and the pair of radiating elements (3 ₃ , 3 ₄ ) of the second antenna element 32 is as follows. It gets bigger as it gets closer.
The reflection plate 1 has bent portions 1a that are bent at opposite ends of the first antenna element 31 and the second antenna element 32 at both ends in the first direction. Here, the first direction reflects the pair of radiating elements (3 ₁ , 3 ₂ ) of the first antenna element 31 or the pair of radiating elements (3 ₃ , 3 ₄ ) of the second antenna element 32. when projected onto the reflection surface of the plate 1, a pair of radiating elements of the first antenna element 31 (3 _{1, 3 2)} connecting the line or the pair of radiating elements of the second antenna element 32 (3 _3, It is parallel to the line connecting 3 ₄ ).

2A and 2B are diagrams showing a half-wave dipole antenna element according to the present embodiment. FIG. 2A is a diagram showing the entire configuration of the dielectric substrate 2 shown in FIG. 1, and FIG. FIG. 2C is a diagram showing a configuration of the front side of the body substrate 2, and FIG. 2C is a diagram showing a configuration of the back side of the dielectric substrate 2.
In FIG. 2, 4 ₁ and 4 ₂ are ground conductors forming a power feeding circuit, 5 ₁ and 5 ₂ are folded conductors constituting the power feeding circuit, and 21 is a slot.
In Fig.2 (a), a continuous line shows what is formed in the front side, and a 2 dot chain line shows what is formed in the back surface side.
As shown in FIG. 2 (b), the front of the dielectric substrate 2 (or rear surface) on the side, a folded conductor 5 ₁ constituting a power supply circuit for the first antenna element 31, the second antenna element 32 a folded conductor 5 ₂ constituting the power supply circuit of the use are formed.
As shown in FIG. 2C, a pair of radiating elements (3 ₁ , 3 ₂ ) of the first antenna element 31 and a second antenna element are provided on the back surface (or front surface) side of the dielectric substrate 2. 32 pairs of radiating elements (3 ₃ , 3 ₄ ) are formed.
The first antenna element 31 and the second antenna element 32 have an electrical length of λ / 2. Here, λ is a free space wavelength of the design center frequency of the antenna.

Further, as shown in FIG. 2C, ground conductors (4 ₁ , 4 ₂ ) are provided on the back surface (or front surface) side of the dielectric substrate 2.
The front end portion of the ground conductor 4 _1, longitudinal slot 21 is provided, each pair of radiating elements (3 _{1, 3 2)} of the first antenna element 31, divided by longitudinal slots 21 It is connected to the divided front end of the ground conductor 4 _1.
Similarly, the front end portion of the ground conductor 4 _2, longitudinal slots 21 are provided, each of the pair of radiating elements of the second antenna element 32 (3 _{3, 3 4),} the longitudinal slot 21 divided is connected to the divided front end of the ground conductor 4 _2.
The folded conductors (5 ₁ , 5 ₂ ) together with a part of the ground conductors (4 ₁ , 4 ₂ ) constitute a balanced-unbalanced conversion circuit (balanced-unbalanced conversion circuit using a microstrip line).
Here, the pair of radiating elements (3 _{1 to} 3 ₄ ), the ground conductors (4 ₁ and 4 ₂ ), and the folded conductors (5 ₁ and 5 ₂ ) are formed by an etching technique or the like used for the printed wiring board. .

FIG. 3 is a diagram for explaining the operation of the dipole antenna of the present embodiment. Now, the width of the reflector 1 in the first direction is λ / 2, the length (edge length) of the bent portion 1a is λ / 8, and the feeding point of the first antenna element 31 and the second antenna element 32 And a pair of radiating elements of the second antenna element 32 and a line connecting the pair of radiating elements (3 ₁ , 3 ₂ ) of the first antenna element 31 with an interval between the reflecting surface of the reflecting plate 1 and the reflecting surface of the reflecting plate 1 being λ / 5 FIG. 4 is a graph showing the change in the half-value width of the directivity in the horizontal plane when the intersection angle (hereinafter referred to as the dipole angle) at the point where the line connecting (3 ₃ , 3 ₄ ) intersects is changed. It is a graph to show.
The feeding point of the first antenna element 31 and the second antenna element 32 means a portion indicated by a circle 23 in FIG.
As shown in FIG. 4, in the dipole antenna of the present example, it can be seen that the full width at half maximum of the directivity in the horizontal plane (YZ plane in FIG. 1) becomes narrower when the dipole angle is increased.
Further, the width of the reflector 1 in the first direction is λ / 2, the length (edge length) of the bent portion 1a is λ / 8, the dipole angle is 90 °, and the first antenna element 31 and the second antenna FIG. 5 is a graph showing a change in the half-value width of the directivity characteristics in the horizontal plane when the distance between the feeding point of the antenna element 32 and the reflecting surface of the reflecting plate 1 is changed.
As shown in FIG. 5, in the dipole antenna of the present embodiment, when the distance between the feeding points of the first antenna element 31 and the second antenna element 32 and the reflecting surface of the reflecting plate 1 is increased, the horizontal plane is increased. It can be seen that the full width at half maximum of the directivity is narrowed.

Further, the width in the first direction of the reflecting plate 1 is λ / 2, the dipole angle is 90 °, and the distance between the feeding point of the first antenna element 31 and the second antenna element 32 and the reflecting surface of the reflecting plate 1 is set. The graph shown in FIG. 6 shows the change in the half-value width of the directivity in the horizontal plane when the length (edge length) of the bent portion 1a is changed as λ / 5.
As shown in FIG. 6, in the dipole antenna of the present example, it can be seen that if the length (edge length) of the bent portion 1 a is increased, the half-value width of the horizontal plane directivity is widened.
FIG. 7 is a graph showing an example of the directivity characteristics in the horizontal plane of the dipole antenna of this example.
7 shows that the width of the reflector 1 in the first direction is λ / 2, the length (edge length) of the bent portion 1a is λ / 8, and the first antenna element 31 and the second antenna element 32 have the same length. It is a graph which shows an actual measurement value in the horizontal plane directivity when the interval between the feeding point and the reflecting surface of the reflecting plate 1 is λ / 5 and the dipole angle is 90 °.
From the graph of FIG. 7, it can be seen that the beam width of the dipole antenna of this example is about 100 °. The beam width is an angle in a range where the relative gain is −3 dB or less.

[Modification]
In the present embodiment, the first half-wavelength dipole antenna element 31 and the second half-wavelength dipole antenna element 32 may be configured as shown in FIG.
FIG. 8 is a view showing a modification of the half-wave dipole antenna element according to the embodiment of the present invention. FIG. 8 (a) is a view showing the entire configuration of the dielectric substrate 2 shown in FIG. 1, and FIG. ) Is a diagram showing the configuration of the front side of the dielectric substrate 2, and FIG. 8C is a diagram showing the configuration of the back side of the dielectric substrate 2.
In Fig.8 (a), a continuous line shows what is formed in the front side, and a 2 dot chain line shows what is formed in the back surface side.
As shown in FIG. 8 (b), the front (or back surface) of the dielectric substrate 2 on the side, and one of the radiating element 3 ₂ of the first antenna element 31, one of the radiation of the second antenna element 32 the element 3 _4, while the feed conductor ₆₁ connected to the radiating element 3 ₂ of the first antenna element 31, a feeding conductor 6 ₂ connected to one radiating element 3 ₄ of the second antenna element 32 Is formed.
As shown in FIG. 8 (c), the rear surface (or front) of the dielectric substrate 2 on the side, the other radiating element 3 of the _first antenna element 31, the other of the radiation of the second antenna element 32 the element _{3 3,} and the ground conductor _{4 1} connected to the radiating element ₃ of the _first antenna element 31, a ground conductor _{4 2} connected to the radiating element _{3 3} of the second antenna element 32 is provided.
The feed conductor (6 ₁ , 6 ₂ ) and the ground conductor (4 ₁ , 4 ₂ ) constitute a feed circuit.
Here, the pair of radiating elements (3 _{1 to} 3 ₄ ), the ground conductors (4 ₁ and 4 ₂ ), and the power supply conductors (6 ₁ and 6 ₂ ) are formed by an etching technique or the like used for the printed wiring board. .

As described above, the two half-wavelength dipole antenna elements of the first antenna element 31 and the second antenna element 32 are arranged in a “C” shape on the dielectric substrate 2 and the reflector plate. 1, a wide-angle beam antenna having a horizontal polarization and a good F / B ratio characteristic in a horizontal plane can be realized by adopting a reflector bent into a “U” shape having a bent portion 1a. it can.
In the present embodiment, the dipole angle of the half-wave dipole antenna elements arranged in a “C” shape, the feeding points of the first antenna element 31 and the second antenna element 32, the reflection surface of the reflector 1, By adjusting the distance and the length (edge length) of the bent portion 1a of the reflecting plate 1, the beam width of directivity in the horizontal plane can be easily adjusted.
Furthermore, since the first antenna element 31 and the second antenna element 32 can be formed on the dielectric substrate 2, it is possible to reduce variation in characteristics when the dipole antenna is mass-produced. For example, the balanced-unbalanced conversion circuit that constitutes the feeding circuit of the first antenna element 31 and the second antenna element 32 can be easily adjusted, and the manufacturing effort can be saved.
As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

It is a model perspective view which shows the dipole antenna of the Example of this invention. It is a figure which shows the half wave dipole antenna element of the Example of this invention. It is a figure for demonstrating operation | movement of the dipole antenna of the Example of this invention. 6 is a graph showing changes in the half-value width of the directivity characteristics in the horizontal plane when the dipole angle is changed in the dipole antenna of the embodiment of the present invention. In the dipole antenna according to the embodiment of the present invention, the change in the half-value width of the directivity in the horizontal plane when the distance between the feeding points of the first antenna element and the second antenna element and the reflecting surface of the reflecting plate is changed. It is a graph to show. In the dipole antenna of the Example of this invention, it is a graph which shows the change of the half value width of the directional characteristic in a horizontal plane when changing the length (edge length) of a bending part. It is a graph which shows an example of the directional characteristic in the horizontal surface of the dipole antenna of the Example of this invention. It is a figure which shows the modification of the half-wavelength dipole antenna element of the Example of this invention. It is a perspective view which shows schematic structure of the conventional dipole antenna.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflector 1a Bending part 2 Dielectric board 3 ₁ -3 ₄ , 13 ₁ , 13 ₂ Radiation element 4 ₁ , 4 ₂ Grounding conductor 5 ₁ , 5 ₂ Folding conductor 6 ₁ , 6 ₂ Feeding conductor 21 Longitudinal slot 30, 31, 32 Antenna element

Claims (2)

A reflector,
A first half-wave dipole antenna element and a second half-wave dipole antenna element disposed on the reflecting surface of the reflector;
In-phase excitation power is supplied to the pair of radiating elements of the first half-wavelength dipole antenna element and the pair of radiating elements of the second half-wavelength dipole antenna element,
The pair of radiating elements of the first half-wavelength dipole antenna element and the pair of radiating elements of the second half-wavelength dipole antenna element are inclined with respect to the reflecting surface of the reflector,
A line connecting a pair of radiating elements of the first half-wavelength dipole antenna element intersects a line connecting a pair of radiating elements of the second half-wavelength dipole antenna element ,
The distance between the pair of radiating elements of the first half-wavelength dipole antenna element and the pair of radiating elements of the second half-wavelength dipole antenna element increases as the distance from the reflector increases. Dipole antenna. The reflector has bent portions that are bent on the opposite sides of the first half-wavelength dipole antenna element side and the second half-wavelength dipole antenna element side at both ends in the first direction.
The first direction connects the pair of radiating elements of the first half-wavelength dipole antenna element when the pair of radiating elements of the first half-wavelength dipole antenna element is projected onto the reflecting surface of the reflector. The dipole antenna according to claim 1, wherein the dipole antenna is parallel to the line.

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