JP4823982B2 - Panel-type fan beam antenna unit and four-plane synthetic omnidirectional antenna device - Google Patents

Description

  The present invention relates to a panel-type fan beam antenna unit disposed on four surfaces of a support to constitute a four-plane combined omnidirectional antenna device, and a four-plane combined omnidirectional device using the panel-type fan beam antenna unit. The present invention relates to an antenna device.

The terrestrial television broadcast is radiated from an omnidirectional antenna device 200 installed on the upper part of the steel tower 100, for example, as shown in FIG. This omnidirectional antenna device 200 is configured as a four-plane synthetic omnidirectional antenna device by arranging panel-type antenna units 210 on four surfaces at the top of the steel tower (90 ° opening angle). Multi-stage arrangement in the vertical direction (for example, see Non-Patent Document 1).
The steel tower 100 is composed of a frame-shaped main body 110 assembled with steel frames and a pole portion 120 installed thereon. The panel type antenna unit 210 includes a flat reflector and a radiator disposed in front of the reflector.

The four-plane synthetic omnidirectional antenna device preferably has a horizontal plane directivity deviation of about 3 dB. In order to realize this, the distance (from the center of the tower 100 to the reflector of the panel type antenna unit 210 ( The projecting distance) needs to be approximately half or less of the wavelength of the used radio wave. This means that the width of the steel tower at the attachment site of the panel type antenna unit 210 needs to be equal to or less than the wavelength of the used radio wave. On the other hand, it is desirable to install the four-plane synthetic omnidirectional antenna device 200 at a position as high as possible.
Therefore, in the four-plane synthetic omnidirectional antenna device 200, each panel type antenna unit 210 is attached to the pole portion 120 of the steel tower 100 as shown.

By the way, when constructing an antenna device for digital terrestrial broadcasting, a steel tower used for an existing analog antenna device is used when it is difficult to secure a new steel tower construction cost or a construction site.
However, when using this existing steel tower, it is often difficult to attach the digital broadcasting antenna to the pole portion 120 due to space limitations. Therefore, it is required to attach the digital broadcasting antenna to the main body 110 of the tower 100. Since the width of the main body 110 is larger than the wavelength of the used radio wave, the four-plane synthetic omnidirectional configuration described above is used. When the antenna device 200 is attached to the main body 110 as the digital broadcasting antenna device, it is difficult to achieve a desired horizontal plane directivity deviation.
“UHF Television Transmission and Reception”, page 385, published on January 20, 1945, published by Denpa Shimbun

In order to solve the above problem, as shown in FIGS. 9 and 10, a multi-plane synthetic omnidirectional antenna device 300 in which a large number of panel type antenna units 310 are arranged in an annular shape (9 in the illustrated example) is used. It is possible to do.
Although not shown, each panel antenna unit 310 has a configuration in which N (N is an integer) radiators are arranged in front of the reflector so as to face in the same direction.
However, since the multi-plane synthetic omnidirectional antenna device 300 has a large number of arranged panel type antenna units 310, a large load (including wind pressure load) is applied to the steel tower. In addition to arranging a large number of panel type antenna units 310, it is necessary to provide a circular gantry (not shown) for arranging and fixing them on the same circumference, which increases the construction cost. Also, the construction period and maintenance time become longer.

Therefore, an object of the present invention is to provide a panel-type fan beam antenna unit capable of obtaining horizontal plane directivity with little directivity deviation by four-plane synthesis even when the width of the support is relatively large.
It is another object of the present invention to provide a four-plane synthetic omnidirectional antenna device configured using the panel-type fan beam antenna unit.

In order to achieve the above object, according to the present invention, there is provided a panel-type fan beam antenna unit disposed on four surfaces of a support for constituting a four-plane synthetic omnidirectional antenna device, and having a predetermined mutual relationship 3 and more radiator adjacent horizontally disposed with an opening angle, and a reflection plate which is disposed respectively in the form facing the radially back to their emitters of each emitter, the opening angle of the There is provided a panel-type fan beam antenna unit characterized in that the horizontal plane directivity is set to show a predetermined fan-shaped pattern.

The fan-shaped pattern is, for example, a horizontal plane directing pattern that rapidly attenuates in the ± 45 ° direction.
Each of the reflecting plates is integrally formed by, for example, bending a single metal plate, but may be formed by an individual metal plate.
In an embodiment of the present invention, the number of the radiators is set to 3, and each of the reflectors is formed by bending the metal plate into a trapezoid.

  As the radiator, a dipole radiating element, a double loop radiating element, or the like can be used. Moreover, you may further provide the electric power divider | distributor which distributes and supplies electric power to each said radiator.

In order to achieve the above object, according to the present invention, there is provided a four-plane synthetic omnidirectional antenna device in which the panel-type fan beam antenna unit is disposed on four surfaces of a support.
In addition, according to the present invention, there is provided an omnidirectional antenna device in which the four-plane synthetic omnidirectional antenna device is arranged in multiple stages in the vertical direction.

According to the panel-type fan beam antenna unit according to the present invention, there are provided three or more radiators arranged adjacent to each other with a predetermined opening angle, and reflectors respectively disposed on the back portions of these radiators. Therefore, for example, it is possible to obtain a fan-shaped beam having a directivity pattern that rapidly attenuates in the ± 45 ° direction.
Further, according to the four-plane synthetic omnidirectional antenna device according to the present invention, the panel-type fan beam antenna unit has a configuration in which the four-sided fan-shaped beam antenna unit is disposed on four surfaces of a support such as a steel tower. It is possible to obtain good horizontal plane directivity with little directivity deviation even under installation conditions where the wavelength is larger than ½ of the wavelength of the radio wave used. That is, for example, when the frequency of the radio wave used is 500 MHz (the frequency of the UHF terrestrial broadcasting band), it has a width that is larger than 60 cm that is the wavelength of the frequency (for example, has a width of 1 m to 3 m). ) It is possible to obtain good horizontal plane directivity with little directivity deviation even under the condition that it is installed in a steel tower.
Since this four-plane synthetic omnidirectional antenna device requires fewer antenna unit arrangement surfaces than the multi-plane synthetic omnidirectional antenna device, the load applied to the support (including wind pressure load) can be reduced and the construction period can be reduced. And maintenance time can be shortened. Further, in the multi-plane synthetic omnidirectional antenna device, a circular frame for arranging and fixing the antenna units in an annular shape must be installed. However, in the four-plane synthetic omnidirectional antenna device according to the present invention, the circular frame is provided with the circular frame. Since it is not necessary, the construction cost and construction period can be reduced. Therefore, the four-plane synthetic omnidirectional antenna device according to the present invention is most suitable as an antenna device for digital terrestrial broadcasting to be additionally installed on an existing steel tower.

Hereinafter, the present invention will be described in detail with reference to the drawings.
1 and 2 are a top view and a front view, respectively, of a panel-type fan beam antenna unit according to an embodiment of the present invention. The antenna unit 1 includes three radiators 2 arranged adjacent to each other with a predetermined opening angle θ, and a reflecting plate 3 disposed on the back of these radiating elements.

In this embodiment, each reflector 3 is integrally formed by bending one rectangular metal plate into a trapezoidal shape. The frame 7 is supported by a support member (not shown).
The radiator 2 in this embodiment includes four dipole radiating elements 5. In the radiating element 5, both element conductors 5 a and 5 b are formed of metal plates, and the surfaces of these element conductors 5 a and 5 b are arranged in parallel to the reflecting plate 3. Since the element conductors 5a and 5b are supported by the reflecting plate 3 through the electrically insulating support column 9, they are separated from the reflecting plate 3 by a distance corresponding to the length of the support column 9.

  As shown in FIGS. 2 and 3, the feeding point of the two radiating elements 5 in the upper half of the set of four radiating elements 5 constituting the radiator 2 is connected to one parallel feeding line conductor 11 a. The feeding points of the two lower radiating elements 5 are connected to the other parallel feeding line conductor 11b. The parallel feed line conductors 11a and 11b are respectively connected to parallel feed line conductors 15a and 15b rising from the coaxial feed pipe 13 shown in FIG. Therefore, the set of four radiating elements 5 and the feed line conductors 11a, 11b, 15a, and 15b constitute a four-dipole antenna as the radiator 2.

As shown in FIG. 1, a power distributor 17 having a three-distribution configuration is disposed in a space formed on the back side of each reflector 3. The power distributor 17 divides input power into three at a predetermined power ratio, and supplies the three distributed outputs to the coaxial power supply pipes 13 provided corresponding to the radiators 2 via coaxial cables 19, respectively. To do. Thereby, the radiating elements 5 of the respective radiators 2 are excited simultaneously.
The phase of the electric power supplied to each radiator 2 can be adjusted by changing the length of the cable 19. The cable 19 is electrically connected to the longitudinal center of the coaxial power supply pipe 13 from the back side of the reflector 3 via a connector 13a such as a connector.
A protective cover 21 indicated by a chain line in FIG. 1 is provided to protect the components of the antenna unit 1 from rain wind, snow, dust, and the like.

The panel-type fan beam antenna unit 1 according to the present embodiment is attached to a pillar such as a steel tower which will be described later in a form in which the four radiating elements 5 of the radiator 2 are arranged in the vertical direction. And this panel type fan-shaped beam antenna unit 1 sets the opening angle θ of each radiator 2 appropriately, and adjusts the distribution ratio and phase of power fed to each of the four dipole antennas, A fan beam can be formed in the opposite direction. That is, according to the fan-shaped beam antenna unit 1, as illustrated in FIG. 4 as an example of the horizontal plane directivity of the single unit, the fan-shaped beam that rapidly attenuates in the ± 45 ° direction (the attenuation amount is approximately 6 dB). It is possible to form. Therefore, the panel-type fan beam antenna unit 1 according to the present embodiment can be used for applications that require radiation only in a range of approximately ± 45 °.
Note that the opening angle θ, the power distribution ratio, the distance between the radiator 2 and the reflector 3, the arrangement interval between the radiators 2, and the like depend on the width and operating frequency of the tower to which the panel-type fan beam antenna unit 1 is attached. Adjusted accordingly.

FIG. 5 is a side view showing an embodiment of a four-plane synthetic omnidirectional antenna device according to the present invention configured using the panel-type fan beam antenna unit 1. 6 is a cross-sectional view taken along line AA in FIG.
The four-plane synthetic omnidirectional antenna device 23 according to the present embodiment is additionally installed as an antenna device for digital terrestrial broadcasting on an existing analog broadcasting tower. That is, the antenna unit 29 that constitutes the four-surface synthetic omnidirectional antenna device 27 for analog broadcasting is already attached to the four surfaces of the pole portion 25 located at the top of the existing analog broadcasting tower. Therefore, the four-plane synthetic omnidirectional antenna device 23 according to the present embodiment is configured by the panel-type fan-shaped beam antenna unit 1 attached to each of the four surfaces of the top portion 31 of the tower main body located below the pole portion 25. ing.

The four-plane synthetic omnidirectional antenna device 23 has a condition that the width of the top portion 31 is larger than the wavelength of the emitted radio wave because each fan-shaped beam antenna unit 1 has directivity as illustrated in FIG. Even in other words, in other words, under the condition that the distance from the tower center to the attachment site is larger than ½ of the wavelength of the emitted radio wave, the combined directivity as illustrated in FIG. However, it is possible to obtain non-directionality within 3 dB.
The synthetic directivity shown in FIG. 7 was obtained under the following conditions.
The distribution ratio of power supplied to the left, center, and right radiators 2 shown in FIG. 1 is 4: 3: 4.
・ Opening angle θ is 15 °
-The spacing between radiators 2 is 510mm
・ The distance of each fan beam antenna unit 1 from the tower center is 1.2m.

  Each antenna unit used in a conventional four-plane composite omnidirectional antenna device for terrestrial television broadcasting shows a pattern in which the directivity of a single unit gradually attenuates as the angle from the front surface increases. Such a fan-shaped beam cannot be formed. Therefore, when this conventional four-plane synthetic omnidirectional antenna device is used under the condition that the tower width is larger than the wavelength of the emitted radio wave, the horizontal plane directivity deviation becomes large and good omnidirectionality is formed. Can not be.

  Moreover, when trying to obtain horizontal plane directivity as illustrated in FIG. 7 under the above-described conditions, the conventional technical common sense uses the above-described multi-plane (six or more planes) combined omnidirectional antenna device. In this case, in addition to the large number of antenna units arranged, it is necessary to provide a circular base for arranging and fixing the antenna units in an annular shape, which increases the load applied to the steel tower and increases the construction cost. It will be bulky.

  On the other hand, according to the four-plane synthetic omnidirectional antenna device 23 according to the present embodiment, good synthetic directivity (omnidirectionality) is obtained even under the above-described condition that the tower width is larger than the wavelength of the emitted radio wave. In addition, since the fan-shaped beam antenna unit 1 can be arranged directly on the four surfaces of the steel tower, the problems of the multi-plane synthetic omnidirectional antenna device can be solved. Therefore, the four-plane synthetic omnidirectional antenna device 23 according to the present embodiment is particularly suitable as an omnidirectional antenna device additionally installed on the existing analog broadcasting tower.

  In the four-plane synthetic omnidirectional antenna device 23 according to the present embodiment, power is distributed and supplied to each fan-shaped beam antenna unit 1 via a power distributor (not shown). In this case, basically, a power distributor that equally distributes the power to each fan beam antenna unit 1 is used. However, in order to adjust the combined directivity on the horizontal plane, a power distributor capable of changing the power distribution ratio to each of the fan beam antenna units 1 may be used.

The four-plane synthetic omnidirectional antenna device 23 according to the present embodiment is arranged in multiple stages in the vertical direction as shown in FIG. 5 as necessary. The four-plane synthetic omnidirectional antenna apparatus having the array configuration shown in FIG. 5 has a configuration in which six stages of the four-plane synthetic omnidirectional antenna apparatus 23 are arranged, but the number of arrangement stages is arbitrary.
In the four-plane combined omnidirectional antenna apparatus having this array configuration, power is distributed and supplied to the four-plane combined omnidirectional antenna apparatus 23 of each stage via a power distributor (not shown). In that case, basically, a power distributor that equally distributes power to the four-plane synthetic omnidirectional antenna device 23 of each stage is used. However, in order to adjust the directivity of the vertical plane (to perform null fill-in), the power distribution that can change the power distribution ratio to the four-plane synthetic omnidirectional antenna device 23 at each stage A vessel may be used.

The present invention is not limited to the above-described embodiment, and includes various modifications. That is, in the panel-type fan beam antenna unit 1 shown in FIG. 1, each reflector 3 is formed by bending a metal plate into a trapezoidal shape, but these reflectors 3 are formed by individual metal plates. May be. The number of radiators 2 may be four or more. In this case, the radiators 2 are arranged adjacent to each other with a predetermined opening angle, and reflectors corresponding to the individual radiators 2 are provided. Arranged.
Further, in the panel-type fan beam antenna unit 1 shown in FIG. 1, a dipole radiating element is used as the radiating element 5 constituting the radiator 2, but other types of radiating elements such as a double loop radiating element are used. May be.

It is a side view of the panel type fan beam antenna unit concerning one embodiment of the present invention. It is a top view of the panel type fan beam antenna unit shown in FIG. It is a perspective view which shows an example of a structure of a radiator. It is the graph which illustrated the directivity of the panel type fan beam antenna unit single-piece | unit shown in FIG. FIG. 2 is a side view of a four-plane synthetic omnidirectional antenna device according to the present invention configured using the panel-type fan beam antenna unit shown in FIG. 1. It is AA sectional drawing of FIG. It is the graph which illustrated the horizontal surface directivity of the 4-plane synthetic | combination omnidirectional antenna device which concerns on this invention. It is a side view which shows the state which attached the conventional 4-plane synthetic | combination omnidirectional antenna apparatus to the steel tower in the pole part of the steel tower. It is the top view which showed schematically an example of the structure of the conventional multi-plane synthetic | combination omnidirectional antenna apparatus. It is a side view of the conventional polyhedral synthetic omnidirectional antenna device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antenna unit 2 Radiator 3 Reflecting plate 5 Radiating element 7 Frame 9 Prop 5
13 Coaxial feeding pipe 21 Protective cover 23 Four-plane synthetic omnidirectional antenna device 25 Pole part 31 Tower top part θ Open angle

Claims (8)

A panel-type fan beam antenna unit disposed on four sides of a support to constitute a four-plane synthetic omnidirectional antenna device,
Three or more radiators arranged adjacent to each other in a horizontal direction with a predetermined opening angle to each other;
A reflector disposed on the back of each radiator in a form facing the radiation direction of the radiator , and
The opening angle of the panel-type fan beam antenna unit, wherein a horizontal plane directivity is set to indicate a predetermined fan pattern.   The panel-type fan-shaped beam antenna unit according to claim 1, wherein the fan-shaped pattern is a directivity pattern that rapidly attenuates in a direction of ± 45 °.   2. The panel-type fan beam antenna unit according to claim 1, wherein each of the reflectors is integrally formed by bending a single metal plate. The panel-type fan-shaped beam antenna unit according to claim 3 , wherein the number of the radiators disposed is 3, and each of the reflectors is formed by bending the metal plate into a trapezoidal shape. .   The panel-type fan-shaped beam antenna unit according to any one of claims 1 to 4, wherein the radiator is constituted by a dipole radiator element or a twin-loop radiator element.   The panel-type fan-shaped beam antenna unit according to claim 1, further comprising a power distributor that distributes and supplies power to each of the radiators.   7. A four-plane synthetic omnidirectional antenna device comprising the panel-type fan beam antenna unit according to claim 1 disposed on four surfaces of a support. A four-plane synthetic omnidirectional antenna apparatus according to claim 7, wherein the four-plane synthetic omnidirectional antenna apparatus is arranged in multiple stages in the vertical direction.

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