JP5449293B2 - antenna - Google Patents

Description

  The present invention relates to an antenna, and more particularly, to a super turn style antenna used for transmitting radio waves for broadcasting and communication.

  Conventionally, as an antenna for transmitting radio waves such as television broadcasting and FM broadcasting, a super turn style antenna (STA) is used in various countries including Japan.

  This STA realizes omnidirectionality of horizontal polarization by attaching four batwing antenna elements made of, for example, monopoles at right angles to each other around a central column and feeding them with a phase difference of 90 °.

  FIG. 13 is a diagram illustrating an example of a conventional super turn style antenna, where (a) is a plan view and (b) is a side view.

  13 (a) and 13 (b), the super-turn style antenna 151 is installed on the iron central pillar 153, and a set of four sets at an angle of 90 ° apart from the central pillar 133. Batwing elements 122a to 122d are attached in multiple stages (Patent Document 1).

  Further, as shown in FIG. 14, in another conventional super turn style antenna 161, a plurality of circular antenna columns 162 having different outer diameters are stacked and welded in order of increasing outer diameter to produce one monopole. The bat wing elements 163 are attached to four locations on the outer peripheral surface of each antenna column (Patent Document 2).

JP 2002-151946 A JP-A-8-222923

  The cylindrical monopole antenna as described above is usually produced by forming a flat plate into a cylindrical shape by bending, but it is difficult to make the cross-sectional shape of the antenna a perfect circle, and the workability (workability) is low. There is a problem of being bad. On the other hand, when the cross-sectional shape is a circle distorted from a perfect circle, the electric field formed in the vicinity of the outer periphery of the cylinder is not uniform, and stable omnidirectionality cannot be realized.

  In addition, when a monopole antenna is configured by stacking a plurality of cylinders in order of increasing outer diameter, there are few overlapping portions between the end faces of adjacent cylinders. There is a problem that strength cannot be obtained. In order to solve this problem, it is conceivable to increase the strength of the monopole antenna by increasing the diameter of the cylinder. However, if the diameter of the cylinder is increased, the batwing elements will inevitably separate from each other. Will collapse.

  In particular, in Japan, since the frequency of earthquakes is high or there is a possibility that STAs may be installed at higher locations as buildings become higher, STAs with further improved strength are highly desired. .

  An object of the present invention is to provide an antenna capable of improving the workability while improving the strength and realizing stable omnidirectionality.

To achieve the above object, the antenna of the present invention comprises a strut, arranged to the four directions as to be substantially perpendicular to each other around said post, and a plurality of batwing antenna elements provided in multiple stages It is an antenna, Comprising: The said support | pillar is comprised by the hollow pillar of a substantially polygonal cross section formed by joining several flat plates .

  Further, the support column is configured by connecting a plurality of hollow columns having substantially the same outer dimensions in the width direction in a substantially vertical direction, and the thickness of one hollow column is disposed above the one hollow column. It is larger than the thickness of other hollow columns.

Further, the antenna of the present invention is further provided with a plurality of feeders that are attached to the surface of the pillars along the longitudinal direction of the pillars and feed power to the plurality of bat wing antenna elements, respectively. It is arranged approximately four times rotationally symmetric with respect to the central axis of the column.

  Furthermore, the antenna of the present invention further includes a substantially U-shaped feed line fixing tool that fixes the feed line to the surface of the support column, and the feed line fixing tool is substantially horizontal in one plane of the support column. A pair of legs attached side by side and a bridge provided on the pair of legs. And the said leg part has a flat bottom face contact | abutted with the said one plane.

Preferably, the support column is a hollow column having a substantially square cross section, and the bat wing antenna element is disposed at a substantially center of each side in the cross section of the hollow column.

According to the present invention, a plurality of bat wing antenna elements are arranged in four directions so as to be substantially perpendicular to each other around the support column, and are provided in multiple stages, and the support column is configured by a hollow column having a substantially polygonal cross section. . Therefore, when a plurality of flat plates having a predetermined width are joined by welding or the like to produce a polygonal column, it is not necessary to perform bending, and a polygonal column with high dimensional accuracy can be provided while improving workability. In addition, since high dimensional accuracy can be realized, a uniform electric field is formed in the vicinity of the outer periphery of the polygonal column, and stable omnidirectionality of horizontal polarization can be realized. Furthermore, when a cylinder with the same width and the same plate thickness is compared with a polygonal column, the circumferential length of the polygonal column is larger than the circumferential length of the column, so that the mechanical strength of the hollow column can be improved.

  In addition, the support column is configured by connecting a plurality of hollow columns having substantially the same outer dimensions in the width direction in a substantially vertical direction, and the thickness of one hollow column is disposed above the one hollow column. It is designed to be larger than the thickness of the hollow column. Therefore, the overlapping part of the end surfaces of the adjacent hollow columns increases, and a sufficient weld surface can be secured, so that the mechanical strength can be further improved.

  Furthermore, since the plurality of feed lines are arranged approximately four times rotationally symmetrically with respect to the central axis of the support column, the symmetry of the plurality of feed lines in the horizontal direction can be realized, and the omnidirectionality of horizontal polarization is improved. can do.

  In addition, since the leg part constituting the feeder fixing device has a flat bottom surface that comes into contact with one plane, it is not necessary to form the bottom surface of the leg part into a curved surface with a predetermined curvature, and when the feeder line is fixed to the support column. It is possible to significantly improve the workability.

Further, since the batwing antenna element is disposed substantially at the center of each side of the hollow column section, it is possible to securely fix the antenna element, it is possible to realize a non-directional horizontal polarization.

1 is a perspective view schematically showing a configuration of a super turn style antenna (STA) according to an embodiment of the present invention. It is a fragmentary sectional view of the perpendicular direction which shows the structure of the support pillar in FIG. Is a side view showing the path of the feed line for supplying power to each batwing antenna elements in FIG. It is sectional drawing of the horizontal direction of STA of FIG. 1, (a)-(d) shows the II cross section, II-II cross section, III-III cross section, and IV-IV cross section, respectively. It is sectional drawing of the horizontal direction of STA of FIG. 1, (a)-(c) shows a VV cross section, a VI-VI cross section, and a VII-VII cross section, respectively. It is an enlarged view which shows the structure of the feeder fixing tool in FIG. 5, (a) is a feeder fixing tool for fixing one, (b) is a feeder fixing tool for fixing two, (c) is three. Fig. 3 shows a fixing device for fixing a power supply line. It is a graph which shows the voltage standing wave ratio (VSWR) characteristic of STA of FIG. It is a figure which shows the directivity of the horizontal polarization of STA in f = 80.5MHz. It is a figure which shows the directivity of the horizontal polarization of STA in f = 90MHz. It is a figure which shows the directivity of the horizontal polarization of STA in f = 99MHz. It is a figure which shows the directivity of the horizontal polarization of STA in f = 108MHz. It is a figure which shows the modification of the support pillar in FIG. It is a figure which shows an example of the conventional STA, (a) is a top view, (b) shows a side view. It is a figure which shows another example of the conventional STA.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view schematically showing a configuration of an antenna according to an embodiment of the present invention.

As shown in FIG. 1, the super turn style antenna (STA) 1 is arranged in four directions so as to be substantially perpendicular to each other around the pillars arranged on the top of the steel tower 8 and provided in multiple stages. and and a plurality of batwing antenna elements. The STA 1 of the present embodiment is configured by arranging the antenna units 2 to 7 as basic units and connecting these units in a line in a substantially vertical direction.

Antenna unit 2 is fixed hollow column 21 of approximately rectangular cross section which constitutes a part of the strut, the batwing antenna element 22 of four which are disposed along the longitudinal direction of the hollow pillar, a bat wing antenna element 22 a pair of upper and lower brackets 23 and 23 which, along the longitudinal direction of the hollow column 21 attached to the surface of the hollow column, and a plurality of feeders 24 which feed respective batwing antenna element 22 of the four Yes.

The bat wing antenna element 22 is configured by joining a plurality of round bar members arranged in the horizontal direction and the vertical direction by welding or the like, and is arranged at the approximate center of each side in the cross section of the hollow column 21. . With this arrangement, the antenna element is securely fixed and omnidirectionality of horizontal polarization is realized.

Feed line 24 supplies power such that the phase difference of 90 ° to batwing antenna elements 22 adjacent to each antenna element. Thereby, the balance of horizontal polarization is maintained. In the present embodiment, for one antenna unit 2, four feeder lines 24 are arranged corresponding to the batwing Ruantena element 22 of four.

  Since the configurations of the antenna units 3 to 7 are basically the same as the configuration of the antenna unit 2, different portions will be described below.

  FIG. 2 is a partial cross-sectional view in the vertical direction showing the configuration of the column in FIG. In FIG. 2, for ease of explanation, the plate thickness of each hollow column is shown to be greatly different, but the plate thickness of each hollow column in the present invention is not limited to the form of FIG. 2.

  In FIG. 2, the support column is configured by connecting a plurality of hollow columns 21, 31, 41,... With substantially equal outer dimensions in the width direction in a substantially vertical direction. Two adjacent hollow columns are joined by welding, for example.

  And the plate | board thickness of one hollow column is designed so that it may become larger than the plate | board thickness of the other hollow column arrange | positioned above this one hollow column. For example, the plate thickness C of the hollow column 41 is larger than the plate thickness B of the hollow column 31, and the plate thickness B of the hollow column 31 is larger than the plate thickness A of the hollow column 21 (A <B <C). In other words, the hollow columns 21, 31, 41,... Have the same outer dimension in the width direction and are stacked in ascending order of the inner dimension in the width direction. According to this structure, the overlap part of the end surfaces of an adjacent hollow pillar increases, and it becomes possible to ensure the welding surface X fully.

Figure 3 is a side view showing the path of the feed line for supplying power to each batwing antenna elements in FIG. FIG. 3 is a view of STA1 as seen from the west side.

Feed line 24,34,44,54,64,74 along the longitudinal direction of the struts attached to the surface of the pillar, respectively, to one end of each feeder line batwing antenna element and the other end connected to the external path Has been. The feeder lines 24, 34, and 44 in the upper three-stage antenna units are sequentially arranged in parallel from the horizontal outer side to the inner side of the hollow column 21. With this arrangement, the feeder lines do not cross each other, and the laying workability of the feeder lines is improved.

The feed lines 54, 64, 74 are arranged on the opposite side of the feed lines 24, 34, 44 with respect to the west wing wing antenna elements 52, 62, 72. The feeder lines 54, 64, and 74 are sequentially arranged in parallel from the horizontal outer side to the inner side of the hollow column 21.

  4 is a horizontal cross-sectional view of the super-turn style antenna 1 of FIG. 3, and FIGS. 4 (a) to 4 (d) are a cross-section taken along the lines II, II-II, III-III, IV-IV cross section is shown. 5A to 5C show a VV cross section, a VI-VI cross section, and a VII-VII cross section, respectively. 5 and 6, the front side is the north positive electrode, the front side is the south negative electrode, the left side is the west positive electrode, and the right side is the east negative electrode.

In the antenna unit 2 (FIG. 4A), an antenna element mounting piece 25 for fixing the bracket 23 is attached to the outer surface of the hollow column 21. One end of the bracket 23 is fixed to the antenna element mounting frame 25, the other end is fixed to the batwing antenna element 22.

In this embodiment, the antenna element mounting piece 25 and the bat wing antenna element 22 are each provided with a through hole (not shown) formed in the horizontal direction. One end of the bracket 23 is provided with another through hole (not shown) corresponding to the through hole of the antenna element mounting piece 25, and the other end is provided with another through hole corresponding to the through hole of the bat wing antenna element 22. A hole (not shown) is provided. By inserting bolts 26 and 27 into these through holes, one end of the bracket 23 is joined to the bat wing antenna element 22 and the other end is joined to the antenna element mounting piece 25.

Further, one end of a jumper wire 28 is connected to the bat wing antenna element 22 and the other end is connected to the feed line 24 via a jumper mounting top 29 (FIG. 4B). With this configuration, predetermined power is supplied to the bat wing antenna element 22 via the jumper wire 28.

The antenna unit 3 is provided with a feed line fixture 35 that fixes the feed line 24 to the surface of the hollow column 31. In the present embodiment, the four feed line fixtures 35 are 4 with respect to the central axis of the hollow column 31. They are arranged rotationally symmetrical (FIG. 4 (c)). Further, one end of a jumper wire 38 is connected to the bat wing antenna element 32, and the other end is connected to the feeder line 34 via a jumper mounting piece 39.

Next, the antenna unit 4 is provided with a feed line fixture 45 that fixes the feed lines 24 and 34 to the surface of the hollow column 41. In the present embodiment, the four power supply line fixtures 45 are arranged in four-fold rotational symmetry with respect to the central axis of the hollow column 41 (FIG. 4D). Further, one end of a jumper wire 48 is connected to the bat wing antenna element 42, and the other end is connected to the feed line 44 via a jumper mounting piece 49.

Further, as shown in FIG. 5A, the antenna unit 5 is provided with a feed line fixture 55 that fixes the feed lines 24, 34, 44 to the surface of the hollow column 51. In the present embodiment, the four power supply line fixtures 55 are arranged in a four-fold rotational symmetry with respect to the central axis of the hollow column 51. One end of a jumper wire 58 is connected to the bat wing antenna element 52, and the other end is connected to the feed line 54 via a jumper mounting piece 49.

The antenna unit 6 includes a feed line fixture 65 for fixing the feed lines 24, 34, 44 to the surface of the hollow column 61, and a feed line 54 for fixing the feed line 54 to the same surface as the surface to which the feed line fixture 65 is attached. An electric wire fixture 66 is provided (FIG. 5B). In the present embodiment, the four power supply line fixtures 65 are arranged in four-fold rotational symmetry with respect to the central axis of the hollow column 61, and the four power supply line fixtures 66 rotate four times with respect to the central axis of the hollow column 61. They are arranged symmetrically. One end of a jumper wire 68 is connected to the bat wing antenna element 62, and the other end is connected to a feed line 64 via a jumper mounting piece 69.

Next, the antenna unit 7 is provided with a feeder line fixture 75 for fixing the feeder lines 24, 34, 44 to the surface of the hollow column 71, and feeder lines 54, 64 on the same surface as the surface to which the feeder line fixture 75 is attached. A feeding line fixture 76 to be fixed is provided (FIG. 5C). In the present embodiment, the four power supply line fixtures 75 are arranged in four-fold rotational symmetry with respect to the central axis of the hollow column 71, and the four power supply line fixtures 76 rotate four times with respect to the central axis of the hollow column 71. They are arranged symmetrically. Further, the batwing antenna element 72 is connected to one end of a jumper wire 78 and the other end connected to the feed line 74 via a jumper mounting frame 79.

  As described above, the antenna units 2 to 7 are configured to fix all of the power supply lines to the unit located above the own unit with the power supply line fixing tool. And the feeder fixing tool of one antenna unit is arranged at substantially the same position as the feeder fixing tools of other antenna units on the projection plane of STA1.

  When the feeder fixtures 35, 45, 55, 65, and 75 are arranged as described above, the feeders 24, 34, 44, 54, 64, and 74 are arranged at the center of the column at any height of the column. It will be arranged in four-fold rotational symmetry with respect to the axis. Therefore, accurate symmetry in the horizontal direction of the plurality of feed lines can be realized, and the omnidirectionality of the horizontal polarization can be improved.

  6 is an enlarged view showing the configuration of the feeder fixing device in FIG. 5, where (a) is a feeder fixing fixture 35 for fixing one, (b) is a feeder fixing fixture 45 for fixing two, (C) shows the feeder fixing tool 55 for fixing three wires.

  The power supply line fixing tool 65 has the same configuration as the power supply line fixing tool 35, and the power supply line fixing tool 75 has the same structure as the power supply line fixing tool 45, and thus description thereof is omitted.

  The feeder fixing tool 35 has a rectangular member body 36 attached to the surface of the hollow column 31 and a tap 37 formed on the main surface of the rectangular member body. Further, the L-shaped bracket is fixed to the tap 37 with a bolt, and the L-shaped bracket is fastened and fixed to the hollow column 31 in a state where the power supply line 24 is sandwiched between the L-shaped bracket and the hollow column 31. Is done.

  The feeder line fixture 45 is a substantially U-shaped fixture that fixes the feeder lines 24 and 34 to the surface of the hollow column 41 (FIG. 6B). The feeder fixing tool 45 includes a pair of leg portions 81 and 81 attached to the flat surface 41a of the hollow column 41 in a substantially horizontal direction, and a plate-like bridge portion 82 attached to the end surfaces of the pair of leg portions 81 and 81. And a pair of leg portions 81 and 81 and a bolt 83 and 83 for joining the bridge portion 82 respectively. The pair of leg portions 81 and 81, the bridge portion 82, and the hollow column 41 define a space in which the two power supply lines 24 and 34 are arranged.

  A sheet-like buffer member 84 is attached to the inner side surfaces of the pair of leg portions 81 and 81 and the bridge portion 82 to prevent disconnection or the like due to contact between the feed line fixing tool 45 and the feed lines 24 and 34. . The buffer member 84 is made of, for example, neoprene rubber.

  The leg portion 81 is, for example, a solid quadrangular prism, and has a flat bottom surface 81a that comes into contact with the flat surface 41a. That is, the bottom surface 81a is formed to be substantially parallel to the flat surface 41a, and the entire bottom surface 81a contacts the flat surface 41a. With this configuration, it is not necessary to form the bottom of the leg part into a curved surface with a constant curvature, and the workability when fixing each feeder line to the support column is significantly improved compared to the case where the support column is a cylinder. Is possible.

  Further, as shown in FIG. 6C, the feeder line fixture 55 is a substantially U-shaped fixture that fixes the feeder lines 24, 34, 44 to the surface of the hollow column 51. The feeder fixing tool 55 includes a pair of leg portions 91 and 91 that are attached to the flat surface 51 a of the hollow column 51 in a substantially horizontal direction, and a plate-like bridge portion 92 that is attached to the end surfaces of the pair of leg portions 91 and 91. And a pair of leg portions 91 and 91 and a bolt 93 and 93 for joining the bridge portion 92 respectively. The pair of leg portions 91, 91, the bridge portion 92, and the hollow column 51 define a space in which the three feeder lines 24, 34, 44 are arranged.

  Further, in the same manner as the power supply line fixing tool 45, disconnection or the like due to contact between the power supply line fixing tool 55 and the power supply lines 24, 34, 44 is prevented on the inner surfaces of the pair of leg portions 91, 91 and the bridge portion 92. A sheet-like cushioning member 94 is attached.

  Thus, by fixing 1 to 3 power supply lines at predetermined positions of the support columns with the respective power supply line fixing tools, 24 power supply lines are reliably fixed to the support columns as a whole of the STA1. Moreover, since a pair of leg part and a bridge part are joined with the volt | bolt, it becomes possible to replace | exchange a feeder wire easily.

  Next, the results of investigating the antenna characteristics of STA1 configured as described above are shown below.

  FIG. 7 is a graph showing the VSWR characteristics of STA1 in FIG.

  As shown in FIG. 7, VSWR is 1.25 or less in the frequency band 75 to 110 MHz, and in particular, VSWR is 1.15 or less in the frequency band 76 to 108 MHz. From this result, it was found that a good voltage standing wave ratio can be obtained in the frequency band by the STA1 of the present invention.

8-11 is a figure which shows the directivity of the horizontal polarization of STA1. In the figure, 0 °, 90 °, 180 °, the direction of 270 ° is the mounting direction of the bat wing antenna elements.

  In the case of f = 80.5 MHz in FIG. 8, although there is a drop in relative gain (Gain) in the directions of about 45 °, 135 °, 225 °, and 315 °, it shows almost omnidirectionality. The gain was as high as about −2.7 dB in the direction.

  When f = 90 MHz (FIG. 9), the gain is about −3.1 or more in all directions, and when f = 99 MHz (FIG. 10), the gain is about −3.5 dB or more in all directions. In the case of f = 108 MHz (FIG. 11), the gain is about −3.6 dB or more in all directions. From this result, it has been found that in the frequency band of f = 90 to 108 MHz, the gain is -3.6 dB or more in all directions, and the omnidirectionality of horizontal polarization can be realized.

As described above, according to the present embodiment, the bat wing antenna elements 22, 32, 42, 52, 62, 72 are arranged in four directions so as to be substantially perpendicular to each other around the support column and are provided in multiple stages. The strut is composed of hollow columns 21, 31, 41, 51, 61, 71 having a substantially polygonal cross section. Therefore, if a plurality of flat plates having a predetermined width are joined to produce a polygonal column, it is not necessary to perform bending, and a polygonal column with high dimensional accuracy can be provided while improving workability. In addition, since high dimensional accuracy can be realized, a uniform electric field is formed in the vicinity of the outer periphery of the polygonal column, and stable omnidirectionality of horizontal polarization can be realized. Furthermore, when a cylinder having the same width and the same plate thickness is compared with a polygonal column, the circumferential length of the polygonal column is larger than the circumferential length of the column, so that the mechanical properties of the hollow columns 21, 31, 41, 51, 61, 71 are increased. Strength, particularly bending strength, can be improved.

  In addition, in the said embodiment, although the hollow pillar 21 is cross-sectional substantially square shape, another cross-sectional shape may be sufficient. For example, as shown in FIG. 12A to FIG. 12C, a hollow column 121 having a generally rhombic cross section, a hollow column 131 having a substantially hexagonal cross section, or a hollow column 141 having a substantially octagonal cross section may be used. Further, the other plurality of hollow columns connected to the hollow column 121 can take a polygonal shape such as a substantially diamond-shaped section, a substantially hexagonal section, or a substantially octagonal section according to the shape of the hollow column 121.

Further, in the hollow column 121 and 131, one of the two adjacent batwing antenna is fixed to the vertex of a rhombus or hexagon or the like. Also according to this modification, the mechanical strength of the hollow column can be improved, and in addition, the degree of freedom in designing the hollow column can be improved.

  Although the STA according to the present embodiment has been described above, the present invention is not limited to the described embodiment, and various modifications and changes can be made based on the technical idea of the present invention.

1 Super Turn Style Antenna (STA)
2,3,4,5,6,7 antenna unit 8 tower 21,31,41,51,61,71 hollow column 22,32,42,52,62,72 batwing antenna elements 23 and 23 a pair of brackets 24 , 34, 44, 54, 64, 74 Feeder line 25 Antenna element mounting pieces 26, 27, 83 Bolts 28, 38, 48, 58, 68, 78 Jumper wires 29, 39, 49, 59, 69, 79 Jumper mounting Tops 35, 45, 55, 65, 66, 75, 76 Feed line fixture 36 Rectangular member body 37 Tap 43, 43 Pair of brackets 53, 53 Pair of brackets 63, 63 Pair of brackets 73, 73 Pair of brackets 81 , 81 A pair of legs 82 A bridge part 84 A buffer member 91, 91 A pair of legs

Claims (5)

An antenna comprising a support and a plurality of bat wing antenna elements arranged in four directions around the support so as to be substantially perpendicular to each other and provided in multiple stages,
The antenna is formed of a hollow column having a substantially polygonal cross section formed by joining a plurality of flat plates . The support column is configured by connecting a plurality of hollow columns having substantially equal outer dimensions in the width direction in a substantially vertical direction,
2. The antenna according to claim 1, wherein a plate thickness of one hollow column is larger than a plate thickness of another hollow column disposed above the one hollow column. Attached to the surface of the strut along the longitudinal direction of the strut, further comprising a plurality of feeders for feeding each of the plurality of batwing antenna elements,
The antenna according to claim 1 or 2, wherein the plurality of feed lines are arranged approximately four times rotationally symmetrically with respect to a central axis of the support column. Further comprising a substantially U-shaped feeding line fixture for fixing the feeding line to the surface of the column,
The feeder fixing tool has a pair of leg portions that are attached to one plane of the support column in a substantially horizontal direction, and a bridge portion that is provided on the pair of leg portions,
The antenna according to claim 3, wherein the leg portion has a flat bottom surface in contact with the one flat surface. The support column is a hollow column having a substantially square cross section,
5. The antenna according to claim 1, wherein the bat wing antenna element is arranged at a substantially center of each side in the cross section of the hollow column.

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