JP2002084130A - Uhf antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact and easily assembled and easily treatable UHF antenna without protruding region. SOLUTION: This UHF antenna is constituted of an almost rectangular radiation conductor 1, whose one face is adhered with a conductive sheet and a reflection conductor 2 arranged in parallel with the back part of the radiation conductor 1 and is formed like almost the same shape, whose one face is adhered with the conductive sheet in the same way. In this case, vertical windows 3 are opened at the central part of the radiation conductor, and feeding points 4 are formed at the right and left walls at the center, and an upper window 5a and a lower window 5b are formed at the central upper and lower positions of the reflection conductor 2, which are almost the same positions as those of the reflection conductor windows 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an antenna for transmitting and receiving terrestrial broadcasting, and more particularly to a UHF antenna for receiving terrestrial digital broadcasting in the UHF frequency band.

[0002]

2. Description of the Related Art As a terrestrial broadcast receiving antenna for receiving a long-wave or medium-wave terrestrial signal, a Yagi-Uda antenna having a waveguide in front of a bar-shaped feed element and a reflector in back is widely used. It's being used.

[0003]

The digital terrestrial broadcasting scheduled to start broadcasting in 2003 has a frequency band of 47.
0 MHz to 690 MHz, and despite the fact that it is the same as the UHF frequency band of conventional analog broadcasting, the reception state does not change according to the strength of the radio wave like an analog signal. Since the antenna can be provided, the receiving antenna only needs to be able to receive a certain level of radio waves, and an antenna having a smaller size and a more easily handled shape than conventional antennas is expected.

However, in the above-mentioned Yagi-Uda type antenna, the length and shape of each element determined by the reception wavelength cannot be largely changed, and a plurality of elongated conductor rods must be used. In particular, the longitudinal direction, which is the direction of the received radio wave, is long and large. In addition, since the number of elements is large, assembly is troublesome, and since the end of each conductor bar is sharp, it is difficult to handle. Therefore, the installation work is also troublesome, the wind pressure load is large, and it is often damaged by a typhoon or the like.

[0005] Therefore, in view of the above problems, it is an object of the present invention to provide a UHF antenna that is small, easy to assemble, and easy to handle without any protruding portions.

[0006]

Means for Solving the Problems To solve the above problems, the present inventors have focused on a slot antenna that can be miniaturized, and have repeated experiments as to whether it can be used for receiving terrestrial broadcasting, especially digital terrestrial broadcasting. Thus, an antenna having good characteristics has been obtained.

In view of the above, a first aspect of the present invention is a UHF antenna comprising a substantially rectangular radiation conductor forming a radio wave radiation surface, and a reflection conductor having substantially the same shape as the radiation conductor and arranged parallel to the back of the radiation conductor. The radiation conductor has an opening window extending in the vertical direction at a central portion, and a feeding point is provided at a central left and right wall portion of the opening window.

According to a second aspect of the present invention, in the first aspect of the present invention, the reflective conductor has an opening window of the same shape in the upper and lower portions at substantially the same position as the opening window of the radiation conductor in the upper and lower positions except for the central portion. And

According to a third aspect of the present invention, in the first aspect of the present invention, the reflecting conductor has substantially the same shape as the opening window of the radiating conductor, and the left and right central portions of the opening window. The power supply point is provided in the portion, and the power is supplied with the polarity opposite to the polarity of the power supply point of the radiation conductor.

A fourth aspect of the present invention is based on any one of the first to third aspects, wherein the reception or transmission wavelength is λ.
The height of the radiation conductor and the reflection conductor is 0.45λ to 0.9λ,
The width is 0.3λ to 0.5λ, and the interval between both is 0.08
λ to 0.25λ.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the left and right side portions of the radiation conductor and the reflection conductor are bent in directions facing each other.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective explanatory view showing an example of a UHF antenna according to the present invention,
It is composed of two conductive plates arranged in parallel, 1 is a radiation conductor which is a radiator, and 2 is a reflection conductor which is a reflector.

The radiating conductor 1 is a rectangular antenna body for radiating or receiving radio waves. A long window 3 is punched out in the center in the vertical direction. It is provided so as to protrude. As an example of the dimensions of each part, for example, the width W of the radiation conductor is 200 mm, the height H is 350 mm, the height L1 of the window is 135 mm, and the width L2 is 50 mm. The width of the projection at the feeding point 4 is 10 mm. Note that these dimensions are as follows: when the reception or transmission frequency is λ, the width W is 0.3λ to 0.5λ, and the height H is H.
From 0.45λ to 0.9λ, and the window length L1 from 0.2λ to
0.4.lambda., And the width L2 of the window is preferably 0.05.lamda. Here, λ is 470 MHz to 690 MHz.
The dimension as z is shown.

The reflection conductor 2 is formed to have the same outer diameter as the radiation conductor 1, and upper and lower windows 5a and 5b are punched out at substantially the same positions as the radiation conductor 1 in the upper and lower portions at the center. The size is, for example, a length L3 of 150 mm and a width L4 of 90 m
m. The windows 5a and 5b have a length L3 of 0.2λ to 0.4λ and a width L4 of 0.05λ to
It is good to be 0.4λ. The radiating conductor 1 and the reflecting conductor 2 are arranged with an interval of 0.08λ to 0.25λ, for example, 60 mm. As described above, since the antenna can be formed into two vertically long rectangular parallelepiped plates having no protrusions, the antenna is small, can be easily installed on a veranda or the like, regardless of a mounting place, and can be easily adjusted in direction and easily handled. In addition, there is no projecting portion, so that the assembly is easy and the wind pressure load is small.

The production of the radiation conductor 1 and the reflection conductor 2 is shown in FIG.
In this method, after the conductive sheet is attached to the dielectric support material, the window is punched and formed as a through hole.However, the window is formed by punching a metal plate such as an aluminum plate or a metal mesh plate, and a resin dielectric is formed. It may be formed by fixing to a body support material. Alternatively, the radiation conductor 1 and the reflection conductor 2 can be directly formed by metal-plating the resin box. Furthermore, a slit-shaped window may be formed in a pattern on a substrate for circuit formation or the like, and fixed to a support member. It should be noted that the distance between the radiation conductor 1 and the reflection conductor 2 can be reduced by interposing a dielectric between them.

The characteristics of the antenna shown in FIG. 1 are shown in FIGS. 2 (a) is an operating gain, FIG. 2 (b) is a standing wave ratio,
2C shows the frequency characteristics of the front-rear ratio, FIG. 3 shows the horizontal polarization horizontal plane directivity performance at 470 MHz, and FIG.
The horizontal polarization horizontal plane directivity performance chart at 60 MHz, FIG.
The horizontal polarization horizontal plane directional performance diagram at 0 MHz is shown.
As shown in these characteristic diagrams, the antenna of FIG.
It can be seen that the device has good characteristics at 0 MHz to 690 MHZ. The window provided in the reflective conductor 2 may not be provided, and the frequency band to be used is a narrow band, but it can be sufficiently used as an antenna.

FIG. 6 shows another embodiment of the present invention, in which the radiation conductor 11 is formed in the same manner as in FIG.
Also, an integrated window 13 is formed by connecting the upper and lower windows, and a feeding point 14 is provided on the left and right wall portions at the center of the window. However, the feeding point 14 of the reflection conductor 12 has a polarity opposite to that of the radiation conductor 11. The characteristics in this case are shown in FIGS. FIG.
7 (a) is an operating gain, FIG. 7 (b) is a standing wave ratio, FIG. 7 (c)
8 shows the frequency characteristics of the front-rear ratio, FIG. 8 shows the horizontal polarization horizontal plane directivity at 470 MHz, FIG. 9 shows the horizontal polarization horizontal plane directivity at 560 MHz, and FIG. 10 shows the horizontal polarization horizontal plane directivity at 680 MHz. As shown in the drawing, a feeding point may be provided also on the reflection conductor, whereby the directivity can be sharpened.

FIG. 11 shows a horizontal polarization vertical plane directivity performance diagram of this antenna, and FIG. 13 shows a representative horizontal polarization vertical plane directivity performance diagram of the Yagi-Uda antenna. From this performance diagram, it can be seen that the vertical plane directivity is improved compared to the Yagi-Uda antenna.

FIG. 12 shows still another embodiment of the present invention. The basic configuration and dimensions are the same as those of FIG. 1, but the left and right sides of the radiation conductor 17 and the reflection conductor 18 are bent so that the left and right sides 17a and 17b of the radiation conductor 17 are rearward and The side parts 18a and 18b are bent forward. However, the amount of bending is determined so that both bent portions do not overlap. In this manner, by bending the left and right sides, the size can be further reduced without greatly changing the characteristics.

In each of the above embodiments, the feeding point is formed by providing a projection on the window. However, a window having a constant width is formed without changing the opening width without providing the projection. Alternatively, a feeding point may be formed on the left and right wall portions at the center of the window. Further, although the shape of the windows of the radiation conductor and the reflection conductor is changed, they may be the same shape.

FIGS. 14 to 17 show a state in which the antenna is specifically installed. FIG. 14 shows a state where the antenna 20 is mounted on a wall or the like of a building. By attaching the mounting jig 21 to the back of the antenna 20, the antenna 20 can be easily mounted on the wall. Further, if a rod-shaped jig 22 is attached to the bottom of the antenna 20, it can be installed at the eaves as shown in FIG. Further, if an eaves mounting jig 23 is mounted on the upper part of the antenna 20, it is easy to mount it under the eaves as shown in FIG. 16, and if a parabolic antenna 25 is installed on a veranda or the like, its mounting pole 24 Using FIG.
The antenna 20 may be attached as shown in FIG. As described above, since the antenna of the present invention has no protruding portion and is small, it can be easily attached to an easy-to-install location regardless of the installation location.

[0022]

As described in detail above, claims 1, 2, 4
According to the invention, since it is small, it can be easily installed on a veranda or the like regardless of a mounting place, and can be easily adjusted in direction and handled. In addition, there is no projecting portion, the assembly is easy, and the wind pressure load is small. Further, the directivity of the vertical plane is sharp.

According to the invention of claim 3, in addition to the effect of claim 1, the directivity can be sharpened. According to the invention of claim 5, in addition to the effects of claims 1 to 4, further downsizing can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective explanatory view of a UHF antenna showing an example of an embodiment of the present invention.

FIGS. 2A and 2B show characteristics of the antenna of FIG. 1, wherein FIG. 2A is an operating gain characteristic diagram, FIG. 2B is a standing wave ratio characteristic diagram, and FIG.

3 is a horizontal polarization horizontal plane directional performance diagram at 470 MHz of the antenna of FIG. 1;

FIG. 4 is a horizontal polarization horizontal plane directivity diagram at 560 MHz of the antenna of FIG. 1;

5 is a horizontal polarization horizontal plane directivity diagram at 680 MHz of the antenna of FIG. 1;

FIG. 6 is an explanatory perspective view showing a second embodiment of the present invention.

7A and 7B show characteristics of the antenna of FIG. 6, wherein FIG. 7A is an operating gain characteristic diagram, FIG. 7B is a standing wave ratio characteristic diagram, and FIG.

8 is a horizontal polarization horizontal plane directivity diagram at 470 MHz of the antenna of FIG. 6;

9 is a horizontal polarization horizontal plane directivity diagram at 560 MHz of the antenna of FIG. 6;

10 is a horizontal polarization horizontal plane directivity performance chart at 680 MHz of the antenna of FIG. 6;

11 is a horizontal polarization vertical plane directivity performance diagram of the antenna of FIG. 6;

FIG. 12 is a perspective explanatory view showing a third embodiment of the present invention.

FIG. 13 is a diagram showing the horizontal polarization vertical plane directivity performance of the Yagi-Uda antenna.

FIG. 14 is an external view showing a state where the antenna of the present invention is mounted on a wall surface.

FIG. 15 is an external view showing a state in which the antenna of the present invention is attached to the eaves.

FIG. 16 is an external view showing a state in which the antenna of the present invention is mounted under an eave.

FIG. 17 is a side view showing a state where the antenna of the present invention is mounted on a parabolic antenna mounting pole.

[Explanation of symbols]

1. radiation conductor, 2. reflection conductor, 3 window, 4 feeding point, 5a upper window, 5b lower window, 11 radiation conductor, 12 reflection conductor, 13 Window, 14, feeding point,
17 radiation conductors, 17a, 17b radiation conductor side,
18. Reflective conductor, 18a, 18b ... Reflector conductor side.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Motokazu Hamano, Inventor F-term (reference) in Mapro Denko Co., Ltd.

Claims (5)

[Claims] 1. A UHF antenna comprising: a substantially rectangular radiation conductor forming a radio wave radiation surface; and a reflection conductor having substantially the same shape as the radiation conductor and arranged parallel to the back of the radiation conductor. A UHF antenna having an opening window extending in the vertical direction at the center, and feeding points provided at the left and right central portions of the opening window. 2. The UHF antenna according to claim 1, wherein the reflective conductor has an opening window of the same shape in the upper and lower portions at substantially the same position as the opening window of the radiation conductor at the upper and lower positions except for the central portion. 3. The reflecting conductor has substantially the same shape as the opening window of the radiation conductor, and has a substantially same shape as the opening window. Feeding points are provided at the center and left and right wall portions of the opening window. The UHF antenna according to claim 1, wherein the power is supplied as the polarity opposite to the polarity of the power supply point. 4. Assuming that the reception or transmission wavelength is λ, the height of the radiation conductor and the reflection conductor is 0.45λ to 0.9λ, the width is 0.3λ to 0.5λ, and the interval between them is 0.08λ. ~
The UHF antenna according to any one of claims 1 to 3, wherein the UHF antenna has a wavelength of 0.25λ. 5. The UHF antenna according to claim 1, wherein left and right sides of the radiation conductor and the reflection conductor are bent in directions facing each other.