JP2015122599A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device for securing omnidirectional properties capable of simplifying a configuration and reducing weight.SOLUTION: The antenna device includes: reflection plates 15, 16; a pair of antennas 50a, 50b, disposed so as to face each other to be plane symmetry through reflection plates 15, 16, respectively having radiation elements 51a to 54a, 51b to 54b; and sub-reflection plates 55, 56 respectively provided on both sides of the reflection plates 15, 16.

Description

  The present invention relates to an antenna device.

  Patent Document 1 discloses a double loop antenna used for broadcasting. In the technique disclosed in Patent Document 1, as shown in FIG. 13, the reflecting plate 1, the linear branch conductor 2 having one end fixed so as to be perpendicular to the reflecting plate 1, and the feeding external conductor 3 a. And the other end of the feeding conductor 3a of the coaxial feeding line 3 and the other end of the branching conductor 2, respectively. Parallel two wires 4 (4a, 4b) that are connected and arranged in parallel with the reflector 1, a jumper 5 that connects the feed inner conductor 3b of the coaxial feed line 3 and the other end of the branch conductor 2, and two parallel wires 4 are connected to both ends of the loop antenna element 6a, 6b, and the direction in which the tip of the loop antenna element 6a, 6b moves away from the loop antenna element 6a, 6b, and the obtuse angle with the reflector 1 from the longitudinal end of the reflector 1 Sub-reflector arranged with Composed of a.

  When trying to obtain omnidirectional characteristics by using such a dual loop antenna, conventionally, as disclosed in Patent Document 2, the outer periphery of the pole so as to surround the mounting column (pole part) at the top of the steel tower It was arranged on four sides. FIG. 14 is a diagram illustrating a configuration of an antenna device installed in a broadcast tower disclosed in Patent Document 2. In FIG. Here, FIG. 14A is a front view of the antenna device, and FIG. 14B is a cross-sectional view taken along the line BB. In FIG. 14, four antenna units 73-1 to 73-4 are provided on the same circumference on the periphery of the pole portion 72, and each antenna unit 73-1 to 73-4 is shifted by 90 °. Are evenly arranged.

JP 2004-015386 A Japanese Patent Application No. 2002-223118

  By the way, in the prior art, in order to obtain the omnidirectional characteristics, it is necessary to arrange four radiating elements because it is necessary to arrange the four objects on the outer periphery of the attachment target (the pole portion 72 in Patent Document 2). As a result, the configuration becomes complicated and the weight increases. In addition, since the wind receiving area is increased, there is a problem in that when it is attached to a steel tower, a burden on the steel tower when receiving wind is increased.

  The present invention has been made in view of the above points, and is an antenna device that ensures omnidirectionality, and provides an antenna device capable of simplifying the configuration and reducing the weight. It is aimed.

In order to solve the above-described problems, the present invention provides a reflector, a pair of antennas disposed so as to be plane-symmetric with respect to the reflector, each having a radiating element, and two sides of the reflector. And a sub-reflection plate provided on each side.
According to such a configuration, the pair of antennas disposed opposite to each other via the reflecting plate and the sub-reflecting plates provided on both sides of the reflecting plate make the bi-directionality of the pair of antennas less effective by the sub-reflecting plate. It can be adjusted to directivity. In addition, compared with the prior art having an antenna unit on the four outer surfaces of the pole, it can be configured with a pair of antennas arranged opposite to each other, so the number of antennas is reduced and the configuration is simplified. It is possible to reduce the weight. In addition, it does not require a pole for attaching four antennas as in the prior art, and it is not necessary to secure a pole arrangement space, so the wind receiving area can be reduced, so the burden on the steel tower can be reduced. it can.

Further, the present invention is characterized in that the antenna is a double loop antenna in which two loops are arranged along the both sides of the reflector.
According to such a configuration, the antenna can be configured with a pair of antennas arranged opposite to each other as compared with the conventional dual loop antenna arranged on the four outer surfaces of the pole in order to realize omnidirectionality. The number can be reduced to simplify the configuration and reduce the weight. In addition, it does not require a pole for attaching four antennas as in the prior art, and it is not necessary to secure a pole arrangement space, so the wind receiving area can be reduced, so the burden on the steel tower can be reduced. it can.

Moreover, the present invention is characterized in that the sub-reflecting plate has a shape extending from the both sides of the reflecting plate toward the radiating element.
According to such a configuration, good omnidirectional characteristics can be obtained.

Further, the present invention is characterized in that an angle formed by the sub-reflecting plate and the reflecting plate is an acute angle.
According to such a configuration, good omnidirectional characteristics can be obtained.

Further, in the present invention, when the wavelength of the radio wave transmitted by the radiating element is λ, from the end on the radiating element side of the sub-reflecting plate to the portion where the sub-reflecting plate and the reflecting plate are in contact with each other The length is 0.11λ to 0.19λ.
According to such a configuration, good omnidirectional characteristics can be obtained.

In the present invention, the reflecting plate is constituted by two plate-like members and two square members arranged between the two plate-like members along both sides. It is characterized by that.
According to such a configuration, it is possible to increase the structural strength and arrange the electric wire in the space surrounded by the square member.

  According to the present invention, this is possible.

It is a perspective view which shows the structural example of the antenna apparatus which concerns on 1st Embodiment of this invention. It is a top view which shows the structural example of the antenna apparatus which concerns on 1st Embodiment of this invention. It is a side view showing an example of composition of an antenna device concerning a 1st embodiment of the present invention. It is sectional drawing which shows the structural example of the antenna apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the horizontal directivity characteristic of 1st Embodiment of this invention. It is a figure which shows the VSWR characteristic of 1st Embodiment of this invention. It is a figure which shows the horizontal directivity characteristic of 1st Embodiment of this invention when a sub-reflector is excluded. It is a figure which shows the horizontal directivity characteristic of 1st Embodiment of this invention when the length of a sub-reflection board is 60 mm. It is a perspective view which shows the structural example of the antenna apparatus which concerns on 2nd Embodiment of this invention. It is a top view which shows the structural example of the antenna apparatus which concerns on 2nd Embodiment of this invention. It is a side view which shows the structural example of the antenna apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the structural example of the antenna apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the example of the conventional antenna device. It is a figure which shows the example of the conventional antenna device.

  Next, an embodiment of the present invention will be described.

(A) Description of Configuration of First Embodiment of the Present Invention FIGS. 1 to 4 are diagrams illustrating a configuration example of an antenna device according to the first embodiment of the present invention. More specifically, FIG. 1 is a perspective view of the antenna device 1 according to the first embodiment, FIG. 2 is a front view of the antenna device 1 viewed from the direction of arrow A shown in FIG. 1, and FIG. FIG. 4 is a side view of the device 1 viewed from the direction of the arrow B shown in FIG. 1, and FIG. 4 is a cross-sectional view of the antenna device 1 taken along the arrow C shown in FIG. As shown in FIG. 1, the antenna device 1 includes a base plate 10 having a circular shape, a lower plate 11, an upper plate 12, sub-reflection plates 55 and 56, radiating elements 51 a to 54 a and radiating elements 51 b to 54 b, and a lightning rod. 80. The antenna device 1 according to the present invention is installed at the tip of a steel tower, for example. Although omitted in FIGS. 1 to 4, in order to protect metal members such as the radiating elements from corrosion due to rain, the radiating elements 51 a to 54 a, 51 b to 54 b, the sub-reflection plates 55, 56, and The power supply lines 64a, 65a, 64b, 65b and the like are preferably housed in a resin radome.

  As shown in FIG. 4, two square pipes 13 and 14 are installed between the base plate 10 and the upper plate 12. The square pipes 13 and 14 are constituted by, for example, aluminum pipes having a square shape of 60 × 30 mm. The square pipes 13 and 14 are arranged along the long sides (sides extending in the vertical direction in FIG. 1), which are both sides of the two reflectors 15 and 16 having a rectangular shape, and are reflected by the square pipes 13 and 14. The plates 15 and 16 are fixed to each other by bolts and nuts. Since the square pipes 13 and 14 and the reflectors 15 and 16 are structurally integrated, the strength against wind force and the like is enhanced.

  At both ends in the width direction of the reflectors 15 and 16 (that is, the long sides of the reflectors 15 and 16), as shown in FIG. 4, sub-reflectors 55 and 56 having a substantially V-shaped cross section are provided. Yes. More specifically, at the left end portions (the end portions on the corner pipe 13 side) of the reflecting plates 15 and 16, the sub-reflecting plate 55 having a substantially V shape is in contact with the left side surface of the square pipe 13. Arranged and fixed to the square pipe 13 by bolts and nuts. A sub-reflecting plate 56 having a substantially V shape is disposed at the right end of the reflecting plates 15 and 16 (the end on the side of the square pipe 14) so that the bottom thereof is in contact with the right side of the square pipe 14, and bolts and It is fixed to the square pipe 14 with a nut or the like. The sub-reflection plate 55 and the sub-reflection plate 56 have the same size and shape. As a result, the sub-reflecting plates 55 and 56 are attached in a state where the respective leading ends are bent inward from the end portions of the reflecting plates 15 and 16. The reflecting plates 15 and 16 and the sub-reflecting plates 55 and 56 are composed of conductive members, and these are electrically connected to each other via the conductive square pipes 13 and 14, so that the reflecting The plates 15 and 16 and the sub reflectors 55 and 56 have the same potential.

  On the front (front) surface of the reflectors 15 and 16 (the surface opposite to the surface on which the square pipes 13 and 14 are disposed), the radiating elements 51a to 54a and 51b to the support plates 31a, 32a, 31b and 32b. 54b are arranged in a line on each surface. The radiating elements 51a to 54a constitute an antenna 50a, the radiating elements 51b to 54b constitute an antenna 50b, and the two antennas 50a and 50b constitute a pair of antennas. The radiating element 51a and the radiating element 51b are arranged to face each other through the reflectors 15 and 16 so as to be plane-symmetric. Similarly, the radiating element 52a and the radiating element 52b, the radiating element 53a and the radiating element 53b, and the radiating element 54a and the radiating element 54b are arranged to face each other through the reflectors 15 and 16, respectively.

  As shown in FIG. 2, the radiating element 51a and the radiating element 52a are connected to each other. Similarly, the radiating element 53a and the radiating element 54a are connected to each other. Although not shown, the radiating element 51b and the radiating element 52b are also connected to each other, and the radiating element 53b and the radiating element 54b are also connected to each other. The radiating elements 51a to 54a constitute one antenna, the radiating elements 51b to 54b constitute one antenna, and the pair of antennas constitute an antenna device.

  As shown in FIG. 4, the radiating elements 54 a and 54 b are disposed on the outer side of the tip portions of the sub-reflecting plates 55 and 56. In other words, in the example of FIG. 4, the radiating element 54 b is disposed outside the tip portions of the sub-reflecting plates 55 and 56 by a distance d. The radiating element 54a and the sub reflectors 55 and 56 are also arranged so as to have the same positional relationship. The positional relationship between the radiating elements 51a to 53a and 51b to 53b and the sub-reflecting plates 55 and 56 is the same as the positional relationship between the radiating elements 54a and 54b and the sub-reflecting plates 55 and 56.

  As shown in FIG. 2, a two distributor 60 is disposed between the base plate 10 and the lower plate 11, and the high frequency signal input to the two distributor 60 is divided into two by a distribution path 61, and a power feeding cable 62, 63. The high-frequency signal supplied to the power supply cable 62 is supplied to the power supply point 37a via the power supply unit 35a. The high frequency signal supplied to the feeding point 37a is supplied to the feeding lines 64a and 65a. Since one end of the feed lines 64a and 65a is connected to the radiating elements 51a and 52a and the other end is connected to the radiating elements 53a and 54a, the high-frequency signal is transmitted via the feed lines 64a and 65a. The radiating elements 51a and 52a and the radiating elements 53a and 54a are supplied. The radiating elements 51a and 52a constitute a double-loop antenna, and radiate high-frequency signals supplied from the feed lines 64a and 65a as radio waves. Similarly, the radiating elements 53a and 54a constitute a double-loop antenna, and radiate high-frequency signals supplied from the feed lines 64a and 65a as radio waves.

  Although not shown, the high-frequency signal distributed to the feeding cable 63 is fed to the feeding point 37b via the feeding unit 35b. The high frequency signal supplied to the feeding point 37b is supplied to the feeding lines 64b and 65b. Since one end of the power supply lines 64b and 65b is connected to the radiating elements 51b and 52b and the other end is connected to the radiating elements 53b and 54b, the high-frequency signal is transmitted through the power supply lines 64b and 65b. It is supplied to the radiating elements 51b and 52b and the radiating elements 53b and 54b. The radiating elements 51b and 52b constitute a double loop antenna, and radiate high-frequency signals supplied from the feed lines 64b and 65b as radio waves. Similarly, the radiating elements 53b and 54b constitute a double loop antenna, and radiate high-frequency signals supplied from the feed lines 64b and 65b as radio waves.

  On the top surface of the upper plate 12, hooks 12 a and 12 b are provided for lifting the antenna device 1 with a crane or the like when the antenna device 1 is installed. Further, a lightning rod 80 is provided to prevent the antenna device 1 from being damaged during a lightning strike.

(B) Description of Operation of First Embodiment of the Invention Next, operation of the first embodiment will be described. FIG. 5 is a diagram illustrating the horizontal directivity characteristics of the first embodiment. FIG. 5 shows the measurement results of the horizontal directivity characteristics at 608 MHz and 470 MHz when the normal direction of the radiating elements 51a to 54a is 0 degrees and the normal direction of the radiating elements 51b to 54b is 180 degrees. Yes. In addition, the result of FIG. 5 is that the length L from the front-end | tip part of the sub-reflection plates 55 and 56 shown in FIG. 4 to the part which the sub-reflection plates 55 and 56 and the reflection plates 15 and 16 contact is 90 mm, An angle θ formed by the sub-reflecting plates 55 and 56 and the reflecting plates 15 and 16 is set to 35 degrees. According to such a setting, as shown in FIG. 5, a horizontal directivity characteristic with a drop of 3 dB or less can be obtained at both 608 MHz and 470 MHz.

  FIG. 6 is a diagram showing a voltage standing wave ratio (VSWR (Voltage Standing Wave Ratio)) characteristic of the first embodiment. In FIG. 6, the horizontal axis represents frequency, and the vertical axis represents VSWR. As shown in FIG. 6, in the first embodiment, the value of VSWR is about 1.100 at 473 MHz and 605 MHz, and the input high-frequency signal has less reflection.

  FIG. 7 shows horizontal directivity characteristics when the sub-reflection plates 55 and 56 are not provided. As shown in this figure, when the sub-reflection plates 55 and 56 are not provided, the direction of 0 degrees that is the normal direction of the radiating elements 51a to 54a and 180 degrees that is the normal direction of the radiating elements 51b to 54b. Bidirectional with strong directivity in the direction. From this result, by providing the sub-reflecting plates 55 and 56, the bi-directionality can be adjusted to be non-directional.

  FIG. 8 shows the horizontal direction when the length L from the tip of the sub-reflection plates 55 and 56 to the portion where the sub-reflection plates 55 and 56 and the reflection plates 15 and 16 contact is changed from 90 mm shown in FIG. 1 to 60 mm. Directivity characteristics are shown. In the example of FIG. 8, the directions at 90 degrees and 270 degrees are reduced by 3 dB or more. From this, it can be understood that the above-described length L needs to be set appropriately. In general, the length L is preferably about 0.11λ to 0.19λ, where λ is the wavelength of the radio wave to be transmitted. The angle θ formed between the sub-reflecting plates 55 and 56 and the reflecting plates 15 and 16 also has an appropriate angle. According to the experimental results, for example, it is desirable that the acute angle is about 30 to 40 degrees.

  As described above, according to the first embodiment, an antenna device having omnidirectionality can be obtained by a pair of antennas (antenna 50a and antenna 50b). For this reason, since it is not necessary to arrange antennas on four sides as in the conventional case, the structure can be simplified and the weight can be reduced. Moreover, since a wind receiving area can be made small, when attaching to a steel tower, the burden to the steel tower at the time of receiving a wind can be reduced.

  In the first embodiment, since the square pipes 13 and 14 are arranged between the reflectors 15 and 16, the weight can be reduced and the structural strength can be increased. Further, since the square pipes 13 and 14 are arranged at both ends in the width direction of the reflectors 15 and 16, the strength is increased by the square pipes 13 and 14, and the distribution path 61 and the feeding cable 62, Space for arranging 63 and the like can be secured.

(C) Description of Configuration of Second Embodiment of Present Invention Next, an antenna device according to the second embodiment of the present invention will be described. FIGS. 9-12 is a figure which shows the structural example of the antenna device 101 which concerns on 2nd Embodiment of this invention. 9 is a perspective view of the antenna device 101 according to the second embodiment, FIG. 10 is a front view of the antenna device 101 viewed from the direction of arrow A shown in FIG. 9, and FIG. FIG. 12 is a side view of the antenna device 101 taken along the arrow C shown in FIG. 11. 9 to 12, parts corresponding to those in the first embodiment shown in FIGS. 1 to 4 are denoted by the same reference numerals, and description thereof is omitted. In the second embodiment, the structures of the radiating elements 151a to 154a and 151b to 154b, the structures of the sub-reflecting plates 155 and 156, and their positional relationships are different from those of the first embodiment. Except for these, the second embodiment is the same as the first embodiment.

  In the first embodiment, as shown in FIG. 4, the radiating elements 51 a to 54 a and 51 b to 54 b are located outside the end portions of the sub-reflecting plates 55 and 56 (configuration of d> 0). However, in the second embodiment, as shown in FIG. 12, the radiation elements 151a to 154a and 151b to 154b and the tip portions of the sub-reflection plates 155 and 156 are in the same position (d≈0). Yes. Further, the bottom portions of the sub-reflecting plates 155 and 156 have a U-shape bent according to the end portions of the reflecting plates 15 and 16. Further, the shapes of the radiating elements 151a to 154a and 151b to 154b are different from the shapes of the radiating elements 51a to 54a and 51b to 54b shown in FIG. Other configurations are the same as those in the first embodiment.

  Also in the second embodiment, the length L from the tip of the sub-reflecting plates 155 and 156 to the portion where the sub-reflecting plates 155 and 156 contact the reflecting plates 15 and 16 is equal to the wavelength λ of the radio wave to be transmitted. It is desirable to be about 0.11λ to 0.19λ. Further, it is desirable that the angle θ formed between the sub-reflecting plates 155 and 156 and the reflecting plates 15 and 16 is an acute angle of about 45 to 55 degrees. With such a setting, an omnidirectional characteristic as shown in FIG. 5 can be obtained, and a VSWR characteristic as shown in FIG. 6 can be obtained.

(M) Description of Modified Embodiment It goes without saying that the above embodiment is merely an example, and the present invention is not limited to the case described above. For example, in each of the embodiments described above, the portion from the sub-reflecting plates 55, 56, 155, and 156 in contact with the reflecting plates 15 and 16 to the tip portion has a linear shape, but this portion has a curved shape. You may do it. For example, in FIG. 4, the sub-reflection plates 155 and 156 may be curved toward the inner side (the reflection plates 15 and 16 side).

  In each of the above embodiments, the sub-reflecting plates 55, 56, 155, and 156 are formed by bending a single plate. However, for example, each of the sub-reflecting plates 55, 56, 155, and 156 may be configured by two plates. . Specifically, taking the sub-reflecting plate 155 as an example, a portion attached to the reflecting plate 15 and a portion attached to the reflecting plate 16 are configured by different members, and each of the reflecting plate 15, You may make it attach to 16.

  In each of the above embodiments, the sub-reflecting plates 55, 56, 155, and 156 are configured by conductive plate-like members. For example, a conductive member is applied or vapor-deposited on the surface of the resin. A member may be used so that the conductive member and the reflectors 15 and 16 are electrically connected.

  Further, in each of the above embodiments, one set of radiating elements constituting the loop antenna is used on each surface, but only one set is used on each surface, or three or more sets are used. May be. Moreover, the shape of the radiation element shown in FIG. 2 and FIG. 10 is an example, and may have other shapes.

  Further, in each of the above embodiments, the two reflecting plates 15 and 16 are used. However, for example, one reflecting plate may be used. In that case, in order to prevent the structural strength from being lowered, for example, the reflector may be thickened, or the honeycomb structure may be provided to increase the strength.

  Further, in each of the above embodiments, the two square pipes 13 and 14 are arranged along the long sides of the two reflecting plates 15 and 16, but in the center of the two reflecting plates 15 and 16. One square pipe may be arranged, or three or more square pipes may be arranged.

  In each of the above embodiments, the sub-reflecting plates 55, 56, 155, and 156 are configured to be directly provided on the long sides of the reflecting plates 15 and 16, but the present invention is not limited to this. Instead, the sub-reflection plate may be provided indirectly on both sides of the reflection plate, such as a sub-reflection plate provided on both sides of the reflection plate via a square pipe.

DESCRIPTION OF SYMBOLS 1,101 Antenna apparatus 10 Base plate 11 Lower plate 12 Upper plate 13, 14 Square pipe 15, 16 Reflector plate 31a, 32a, 31b, 32b Post 35a, 36a, 35b, 36b Feed part 37a, 37b Feed point 50a, 50b Antenna 51a to 54a, 51b to 54b Radiating element 60 2 Distributor 61 Distribution path 62, 63 Feeding cable 64a, 65a, 64b, 65b Feeding line 80 Lightning rod 151a to 154a, 151b to 154b Radiating element 155, 156 Sub reflector

Claims (6)

A reflector,
A pair of antennas arranged to face each other through the reflector plate, each having a radiating element;
Sub-reflection plates provided on both sides of the reflection plate,
An antenna device.   The antenna apparatus according to claim 1, wherein the antenna is a double-loop antenna in which two loops are arranged along the both sides of the reflector.   3. The antenna device according to claim 1, wherein the sub-reflecting plate has a shape that extends from the both sides of the reflecting plate toward the radiating element. 4.   The antenna device according to claim 3, wherein an angle formed by the sub-reflecting plate and the reflecting plate is an acute angle.   When the wavelength of the radio wave transmitted by the radiating element is λ, the length from the end of the sub-reflecting plate on the radiating element side to the portion where the sub-reflecting plate and the reflecting plate are in contact is 0.11λ The antenna device according to claim 3, wherein the antenna device is 0.19λ.   The said reflecting plate is comprised by two plate-shaped members, and two square members arrange | positioned along these both sides between these two plate-shaped members, It is characterized by the above-mentioned. Item 6. The antenna device according to any one of Items 1 to 5.

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