Antenna Device

Abstract

To expand the wireless communication service area above ground of antenna devices placed in manholes and other underground spaces.SOLUTION: An antenna device includes six vertically polarized monopole antennas arranged equally spaced on a first circumference and six horizontally polarized dipole antennas arranged equally spaced on a second circumference. The antenna device forms a first array antenna with three vertically polarized monopole antennas of 0, 120, and 240 degrees, a second array antenna with three vertically polarized monopole antennas of 60, 180, and 300 degrees, a third array antenna with three horizontally polarized dipole antennas of 30, 150, and 270 degrees, and a fourth array antenna with three horizontally polarized dipole antennas of 90, 210, and 330 degrees.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an antenna device. [Background technology]

[0002] Conventionally, an antenna device that is installed in a manhole is known (see, for example, Patent Document 1). The antenna device described in Patent Document 1 includes an antenna element, an installation stand on which the antenna element is installed, a container that has an open top surface that is the surface closest to the ground surface when installed underground and that houses the antenna element and the installation stand, and a lid that is made of FRP (Fiber Reinforced Plastics) and covers the opening of the container, and the installation stand is provided with a height adjustment mechanism that adjusts the distance from the antenna element to the lid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-177632 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional antenna device described above, adjustments can be made to satisfy the radio wave protection guidelines by adjusting the distance from the antenna element to the manhole cover, but since the antenna directivity is not taken into consideration, it is insufficient for expanding the wireless communication service area on the ground.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to expand the above-ground wireless communication service area of ​​an antenna device disposed in an underground space such as a manhole. [Means for solving the problem]

[0006] One aspect of the present invention is an antenna device that is placed in an underground space extending from the ground surface toward the underground, and comprises six vertically polarized monopole antennas arranged at equal intervals on a first circumference and six horizontally polarized dipole antennas arranged at equal intervals on a second circumference, wherein a first array antenna is formed by three of the vertically polarized monopole antennas arranged at 0 degrees, 120 degrees, and 240 degrees, a second array antenna is formed by three of the vertically polarized monopole antennas arranged at 60 degrees, 180 degrees, and 300 degrees, a third array antenna is formed by three of the horizontally polarized dipole antennas arranged at 30 degrees, 150 degrees, and 270 degrees, and a fourth array antenna is formed by three of the horizontally polarized dipole antennas arranged at 90 degrees, 210 degrees, and 330 degrees.

[0007] One aspect of the present invention is an antenna device that is placed in an underground space extending from the ground surface toward the underground, and comprises six vertically polarized monopole antennas arranged at equal intervals on a circle, wherein a first array antenna is formed by three of the vertically polarized monopole antennas arranged at 0 degrees, 120 degrees, and 240 degrees, and a second array antenna is formed by three of the vertically polarized monopole antennas arranged at 60 degrees, 180 degrees, and 300 degrees.

[0008] One aspect of the present invention is an antenna device that is placed in an underground space extending from the ground surface toward the underground, and includes six horizontally polarized dipole antennas arranged at equal intervals on a circle, wherein a first array antenna is formed by three of the horizontally polarized dipole antennas arranged at angles of 30 degrees, 150 degrees, and 270 degrees, and a second array antenna is formed by three of the horizontally polarized dipole antennas arranged at angles of 90 degrees, 210 degrees, and 330 degrees.

[0009] In one aspect of the present invention, the antenna device further comprises a cylindrical circle disposed at the center of the circumference. Effect of the Invention

[0010] According to the present invention, it is possible to obtain an effect that it is possible to expand the radio communication service area on the ground of an antenna device disposed in an underground space such as a manhole. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an explanatory diagram for explaining an example of arrangement of an antenna device according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram for explaining an example of arrangement of an antenna device according to an embodiment. [Diagram 3] 1 is a diagram illustrating a configuration example of an antenna device according to an embodiment; [Figure 4] FIG. 2 is a dimensional diagram of an antenna device according to an embodiment. [Diagram 5] FIG. 2 is a dimensional diagram of an antenna device according to an embodiment. [Figure 6] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 7] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 8] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 9] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 10] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 11] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 12] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 13] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 14] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. [Figure 15] 11A and 11B are diagrams illustrating simulation results of the antenna device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 are explanatory diagrams for explaining an example of arrangement of an antenna device 10 according to an embodiment, where FIG. 1 is a diagram seen from the side and FIG. 2 is a diagram seen from above.

[0013] The antenna device 10 is disposed in a manhole 4. The manhole 4 is a space (underground space) formed underground 2. The manhole 4 is provided from the ground surface 3 toward the underground. A manhole cover 1 is provided on the ground surface 3 for the manhole 4. The manhole cover 1 is a cover that covers the manhole 4.

[0014] The material of the manhole cover 1 is preferably a material that does not affect the radio wave propagation of the antenna device 10 placed in the manhole 4. The material of the manhole cover 1 is, for example, FRP (Fiber Reinforced Plastics).

[0015] A cable 20 such as a communication cable or an electric cable is connected to the antenna device 10 placed in the manhole 4. The cable 20 transmits and receives signals and supplies power to the antenna device 10.

[0016] Fig. 3 is a diagram showing a configuration example of the antenna device 10 according to this embodiment, as viewed from above. Fig. 3 shows the arrangement on a horizontal plane (xy plane). In Fig. 3, the z-axis direction is the vertical direction.

[0017] The antenna device 10 includes six vertically polarized monopole antennas 11 (11-1, 11-2, 11-3, 11-4, 11-5, 11-6), six horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6), and a circular shape 15.

[0018] The ground plane 100 is a flat conductor. The ground plane 100 is provided with the power feeders 12 (12-1, 12-2, 12-3, 12-4, 12-5, 12-6) of the vertically polarized monopole antennas 11 (11-1, 11-2, 11-3, 11-4, 11-5, 11-6). The vertically polarized monopole antennas 11 (11-1, 11-2, 11-3, 11-4, 11-5, 11-6) are fed with power from the power feeders 12 (12-1, 12-2, 12-3, 12-4, 12-5, 12-6).

[0019] The ground plate 100 is provided with the power feed units 14 (14-1, 14-2, 14-3, 14-4, 14-5, 14-6) of the horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6). The horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6) are disposed at a constant height from the ground plate 100. The horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6) are fed with power from the power feed units 14 (14-1, 14-2, 14-3, 14-4, 14-5, 14-6) via feeder lines (not shown).

[0020] Six vertically polarized monopole antennas 11 (11-1, 11-2, 11-3, 11-4, 11-5, 11-6) are arranged at equal intervals on a first circumference. Vertically polarized monopole antenna 11-1 is arranged at 0 degrees, vertically polarized monopole antenna 11-2 is arranged at 60 degrees, vertically polarized monopole antenna 11-3 is arranged at 120 degrees, vertically polarized monopole antenna 11-4 is arranged at 180 degrees, vertically polarized monopole antenna 11-5 is arranged at 240 degrees, and vertically polarized monopole antenna 11-6 is arranged at 300 degrees.

[0021] The antenna device 10 configures a first array antenna with three vertically polarized monopole antennas 11-1, 11-3, and 11-5 arranged at angles of 0 degrees, 120 degrees, and 240 degrees. The antenna device 10 configures a second array antenna with three vertically polarized monopole antennas 11-2, 11-4, and 11-6 arranged at angles of 60 degrees, 180 degrees, and 300 degrees.

[0022] Six horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6) are arranged at equal intervals on the second circumference. Horizontally polarized dipole antenna 13-1 is arranged at 30 degrees, horizontally polarized dipole antenna 13-2 is arranged at 90 degrees, horizontally polarized dipole antenna 13-3 is arranged at 150 degrees, horizontally polarized dipole antenna 13-4 is arranged at 210 degrees, horizontally polarized dipole antenna 13-5 is arranged at 270 degrees, and horizontally polarized dipole antenna 13-6 is arranged at 330 degrees.

[0023] The antenna device 10 configures a third array antenna with three horizontally polarized dipole antennas 13-1, 13-3, and 13-5 arranged at angles of 30 degrees, 150 degrees, and 270 degrees. The antenna device 10 configures a fourth array antenna with three horizontally polarized dipole antennas 13-2, 13-4, and 13-6 arranged at angles of 90 degrees, 210 degrees, and 330 degrees.

[0024] The first circumference on which the vertically polarized monopole antenna 11 is arranged and the second circumference on which the horizontally polarized dipole antenna 13 is arranged are concentric circles. The first circumference on which the vertically polarized monopole antenna 11 is arranged is located inside the second circumference on which the horizontally polarized dipole antenna 13 is arranged.

[0025] The circle 15 has a cylindrical shape and is disposed at the center of the first circumference and the second circumference.

[0026] Figures 4 and 5 are dimensional diagrams of the antenna device 10 according to this embodiment, with Figure 4 being a diagram seen from above and Figure 5 being a diagram seen from a side. Figure 4 shows the arrangement on a horizontal plane (xy plane). In Figure 4, the z-axis direction is the vertical direction. Figure 5 shows the arrangement on a vertical plane (xz plane).

[0027] Vertically polarized monopole antenna 11 is rod-shaped and has a length of H1. Horizontally polarized dipole antenna 13 has a total length of W1, and is fed from feeding point 14 to the midpoint of the total length. Horizontally polarized dipole antenna 13 is disposed at a height H2 from ground plate 100 by an insulator (not shown).

[0028] Vertically polarized monopole antenna 11 is positioned at a distance D1 from the center of the first circumference (the center of circle 15). Horizontally polarized dipole antenna 13 is positioned at a distance D2 from the center of the second circumference (the center of circle 15).

[0029] The circle 15 is cylindrical, the radius of the cylinder is R1, and the height of the cylinder is H3.

[0030] Next, the effects of the antenna device 10 according to this embodiment will be described with reference to FIGS.

[0031] Figures 6 to 15 are diagrams showing simulation results of the antenna device 10 according to this embodiment. The antenna device 10 used in the simulations shown in Figures 6 to 15 has dimensions in Figures 4 and 5 described above of "W1 = 36 millimeters (mm), D1 = 38 mm, D2 = 48 mm, H1 = 17 mm, H2 = 26 mm, H3 = 30 mm, R1 = 15 mm."

[0032] Fig. 6 is a graph showing the return loss characteristics of a first array antenna and a second array antenna formed of a vertically polarized monopole antenna 11. Fig. 7 is a graph showing the return loss characteristics of a third array antenna and a fourth array antenna formed of a horizontally polarized dipole antenna 13. In Figs. 6 and 7, the horizontal axis is frequency (unit: gigahertz (GHz)), and the vertical axis is return loss (unit: decibels (dB)).

[0033] As shown in the graphs of Figures 6 and 7, in the 3.5 GHz band used, the return loss for vertical polarization was less than -7 dB, and the return loss for horizontal polarization was less than -9 dB, showing good results for both vertical and horizontal polarization.

[0034] Figures 8 to 11 are diagrams showing radio wave radiation patterns of a first array antenna and a second array antenna configured with a vertically polarized monopole antenna 11. Figures 12 to 15 are diagrams showing radio wave radiation patterns of a third array antenna and a fourth array antenna configured with a horizontally polarized dipole antenna 13. The frequency band used in the simulation of the radio wave radiation patterns in Figures 8 to 15 is the 3.5 GHz band.

[0035] Fig. 8 shows a radio wave radiation pattern in the vertical plane of the first array antenna constituted by the vertically polarized monopole antenna 11. As shown in the radio wave radiation pattern in the vertical plane of Fig. 8, the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction). A null is formed in the sky direction (z-axis direction). Since the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction), even if the antenna device 10 is placed in a manhole 4, the effect of expanding the wireless communication service area on the ground can be obtained.

[0036] Fig. 9 shows a radio wave radiation pattern in the vertical plane of the second array antenna constituted by the vertically polarized monopole antenna 11. As shown in the radio wave radiation pattern in the vertical plane of Fig. 9, the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction). A null is formed in the sky direction (z-axis direction). Since the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction), even if the antenna device 10 is placed in a manhole 4, the effect of expanding the wireless communication service area on the ground can be obtained.

[0037] Fig. 10 shows the radio wave radiation pattern in the horizontal plane of the first array antenna composed of the vertically polarized monopole antenna 11. As shown in the radio wave radiation pattern in the horizontal plane of Fig. 10, good radiation intensity is obtained in almost all directions.

[0038] Fig. 11 shows the radio wave radiation pattern in the horizontal plane of the second array antenna formed by the vertically polarized monopole antenna 11. As shown in the radio wave radiation pattern in the horizontal plane of Fig. 11, good radiation intensity is obtained in almost all directions.

[0039] Fig. 12 shows a radio wave radiation pattern in the vertical plane of the third array antenna constituted by the horizontally polarized dipole antenna 13. As shown in the radio wave radiation pattern in the vertical plane of Fig. 12, the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction). A null is formed in the sky direction (z-axis direction). Since the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction), even if the antenna device 10 is placed in a manhole 4, the effect of expanding the wireless communication service area on the ground can be obtained.

[0040] Fig. 13 shows a radio wave radiation pattern in the vertical plane of the fourth array antenna constituted by the horizontally polarized dipole antenna 13. As shown in the radio wave radiation pattern in the vertical plane of Fig. 13, the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction). A null is formed in the sky direction (z-axis direction). Since the main lobe is oriented more toward the ground surface (x-axis direction) than toward the sky (z-axis direction), even if the antenna device 10 is placed in a manhole 4, the effect of expanding the wireless communication service area on the ground can be obtained.

[0041] Fig. 14 shows the radio wave radiation pattern in the horizontal plane of the third array antenna formed by the horizontally polarized dipole antenna 13. As shown in the radio wave radiation pattern in the horizontal plane of Fig. 14, good radiation intensity is obtained in almost all directions.

[0042] Fig. 15 shows the radio wave radiation pattern in the horizontal plane of the fourth array antenna formed by the horizontally polarized dipole antenna 13. As shown in the radio wave radiation pattern in the horizontal plane of Fig. 15, good radiation intensity is obtained in almost all directions.

[0043] As described above, according to this embodiment, the radio wave radiation pattern in the vertical plane of the antenna device 10 can be directed toward the ground surface rather than toward the sky. This provides the effect of expanding the ground-based wireless communication service area of ​​the antenna device 10 installed in the manhole 4.

[0044] Moreover, according to this embodiment, a total of four array antennas are configured, including a first array antenna and a second array antenna using vertically polarized monopole antennas 11, and a third array antenna and a fourth array antenna using horizontally polarized dipole antennas 13. This makes it possible to perform four-branch MIMO (Multi Input Multi Output) communication.

[0045] In the above-described embodiment, both the vertically polarized monopole antenna 11 and the horizontally polarized dipole antenna 13 are used, but the present invention is not limited to this.

[0046] For example, in FIG. 3, the six horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6) may be removed, and the first and second array antennas may be configured using only the six vertically polarized monopole antennas 11 (11-1, 11-2, 11-3, 11-4, 11-5, 11-6).

[0047] For example, in FIG. 3, the six vertically polarized monopole antennas 11 (11-1, 11-2, 11-3, 11-4, 11-5, 11-6) may be removed, and the first and second array antennas may be configured using only the six horizontally polarized dipole antennas 13 (13-1, 13-2, 13-3, 13-4, 13-5, 13-6).

[0048] In the above-described embodiment, the circle 15 is provided, but the circle 15 does not necessarily have to be provided.

[0049] Furthermore, in the above-described embodiment, the first circumference on which the vertically polarized monopole antenna 11 is arranged and the second circumference on which the horizontally polarized dipole antenna 13 is arranged are concentric circles, and the first circumference is located inside the second circumference, but the opposite may also be true, that is, the first circumference may be located outside the second circumference.

[0050] In addition, in the above-described embodiment, the antenna device 10 is placed in the manhole 4, but the underground space in which the antenna device 10 is placed is not limited to the manhole 4, and the antenna device 10 may be placed in an underground space other than the manhole 4.

[0051] This will, for example, make it possible to improve the overall service quality in wireless networks, thereby contributing to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0052] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present invention are also included. [Explanation of symbols]

[0053] 1...manhole cover, 2...underground, 3...ground surface, 4...manhole, 10...antenna device, 11...vertically polarized monopole antenna, 13...horizontally polarized dipole antenna, 12, 14...power supply unit, 15...circular, 20...cable, 100...ground plate

Claims

1. An antenna device disposed in an underground space extending from the ground surface toward the underground, six vertically polarized monopole antennas equally spaced on a first circumference; six horizontally polarized dipole antennas equally spaced on a second circumference; A first array antenna is configured by three of the vertically polarized monopole antennas arranged at 0 degrees, 120 degrees and 240 degrees, a second array antenna is formed by three of the vertically polarized monopole antennas arranged at 60 degrees, 180 degrees and 300 degrees, a third array antenna is formed by three of the horizontally polarized dipole antennas arranged at 30 degrees, 150 degrees and 270 degrees, A fourth array antenna is constituted by three of the horizontally polarized dipole antennas arranged at 90 degrees, 210 degrees and 330 degrees. Antenna device.

2. Further comprising a cylindrical circle disposed at a central portion of the circumference.

2. The antenna device according to claim 1.

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