JPH0728728Y2 - An artificial satellite equipped with an omnidirectional antenna - Google Patents

Description

TECHNICAL FIELD The present invention relates to an artificial satellite equipped with an omnidirectional antenna.

Prior Art Artificial satellites are often equipped with omnidirectional antennas. Generally four or eight omnidirectional antennas
A turnstile antenna consisting of a book whip antenna is used.

The whip antenna will be described. Considering a whip antenna mounted on an artificial satellite as shown in Fig. 10, the directivity in the horizontal plane (θ = 90 °) orthogonal to the θ axis is
On the other hand, it becomes almost circular as shown in FIG. 11, while the directivity in the vertical plane including the θ-axis becomes a figure of 8 as shown in FIG. Next, in the turnstile antenna, four whip antennas are spatially displaced by 90 ° as shown in Fig. 13, and the phases of the currents to be fed are shifted by 2 / πrad respectively, and d in the figure is small. Is desirable. Further, the four whip antennas may be arranged on the same plane as shown in FIG. 13 or may be arranged at an inclination.

For each whip antenna that makes up the turnstile antenna, its size is 1/4 wavelength of the frequency used, for example 18.75 cm if the frequency is 400 MHz.
The thickness is not particularly limited, but the diameter is, for example, about 2 mm. In addition, the polarization characteristics will be circular polarization, and if the ground antenna is right-hand circular polarization, it will be right-hand circular polarization to match it.

FIG. 1 is a side view of an artificial satellite equipped with this whip antenna. This satellite has a size larger than the wavelength used, is provided with a solar cell paddle 2, and four whip antennas 6 and 7 are mounted on the upper panel 3 and the lower panel 4 of the satellite body 1, respectively. Now, if the angle θ is taken from the center of the satellite as shown in the figure, the whip antenna 6
The radiation patterns of the hemispherical surfaces shown by (4) and the whip antenna 7 (4) are shown in FIGS. 2 and 3, respectively.
The lines connecting 90 ° and 270 ° are symmetrical with each other. That is, for such an artificial satellite having a size larger than the wavelength used and having the solar cell paddle 2 attached, the antenna can be changed by switching the whip antenna 6 (4 pieces) and the whip antenna 7 (4 pieces). An omnidirectional antenna radiation pattern that radiates power substantially uniformly is secured in all directions centered at, ie, all solid angles (4π steradians).

However, in recent years, as the size of artificial satellites has increased, the diameter of the rocket coupling part (5 in Fig. 1) has also increased and the total length has become longer (for example, conventionally, the diameter was 376 mm and the total length was 35 mm. In recent years, it has become 650mm in diameter and 200mm in total length.)
When the lower whip antenna is mounted on the lower panel as in the conventional case, the following problems occur. First, because the diameter of the rocket-coupled portion is large, the spacing between the whip antennas also becomes large, and there is a portion in which the radio waves radiated by each whip antenna have opposite phases, and θ = 90
The level fluctuation in the direction of ° becomes large. For example, in the case of four whip antennas, the radiation pattern in the horizontal plane (θ = 90 °) becomes nonuniform as the diameter of the rocket coupling part increases, as shown in FIG. Therefore, it is necessary to take measures such as increasing the number of whip antennas. Secondly, since the rocket coupling part becomes long, the reflected wave from the rocket coupling part becomes large, and the antenna radiation pattern is disturbed by the interference with the direct wave of the whip antenna, making it difficult to obtain a hemispherical radiation pattern. Become. That is, when the number of elements is increased to, for example, 8 elements, the radiation pattern in the horizontal plane is improved, but when the coupling portion with respect to the rocket becomes long, due to this, a cut occurs near θ = 125 °.

Fig. 4 shows a solar cell paddle 12 attached, and has a paired rocket coupling part 15 whose diameter and total length are larger than those in Fig. 1, and whip antennas 16 (4) 17 (8) as shown in Fig. 1. FIG. 5 is a side view of the artificial satellite mounted on each of the upper panel 13 and the lower panel 14 of the artificial satellite body 11, and FIG.
FIG. 6 shows the antenna radiation pattern of the whip antenna 17 (8 pieces) in this case (the angle θ is the same as in FIG. 1).
Shows that there is a notch near θ = 125 °. That is, the radiation pattern of the hemispherical surface as shown in FIGS. 2 and 3 cannot be obtained, and the omnidirectional antenna radiation pattern cannot be realized.

Therefore, the purpose of the present invention is to install an omnidirectional antenna in which an omnidirectional antenna is mounted so that an omnidirectional antenna radiation pattern can be obtained even when the size of the anti-rocket coupling part is large. It is to provide satellites.

For this purpose, the present invention mounts an omnidirectional antenna on the separation surface of the anti-rocket coupling part of the satellite.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 7 is a side view of an artificial satellite having an omnidirectional antenna radiation pattern according to an embodiment of the present invention, and FIG. 8 is a bottom view thereof. Four upper whip antennas 26 are mounted on the upper panel 23 of the artificial satellite body 21 to which the solar cell paddles 22 are attached, as in the conventional case. The lower whip antenna 27 is located at the
Four are mounted on the separation surface 28 of. As described above, by mounting the whip antenna 27 on the separation surface of the paired rocket coupling portion 25, the inter-antenna distance can be made smaller than that when mounted on the lower panel 24. Therefore, the radio waves radiated by each whip antenna 27 are not in antiphase, the level fluctuation in the direction of θ = 90 ° is small, and the antenna is close to a hemispherical surface with no notch near θ = 125 °. A radiation pattern (Fig. 9) is obtained. Further, since the whip antenna 27 is attached to the separation surface 28 of the anti-rocket coupling part 25, it is not affected by the reflected wave from the anti-rocket coupling part 25. Note that the rocket-side coupling portion to which the rocket-to-rocket coupling portion 25 is coupled, that is, the satellite separation portion, is, for example, "25th
Proceedings of the Annual Meeting of the Space Science and Technology Federation, page 82, Fig. 1, Showa
It has a cylindrical structure as shown in "Kyoto Kaikan, 22-23 October, 1976". Therefore, at the time of coupling, the whip antenna 27 mounted inside the edge of the rocket separation surface 28 is
It will be housed inside the satellite separation unit of cylindrical structure.

FIGS. 15 (A), (B), (C), and (D) relate to the present invention, the structure of the anti-rocket joint, the structure of the separating surface of the joint, the structure of attaching the whip antar to the separating surface, and The rocket side coupling structure is shown respectively. In addition, in (C), the separation surface is actually a belt whose periphery is fixed. Further, in (C), 29 indicates the edge of the separation surface, and the antenna is arranged inside this edge.

Effects of the Invention As described above, in the artificial satellite equipped with the omnidirectional antenna of the present invention, the whip antenna is mounted on the separation surface of the rocket coupling part, so that (1) the distance between the whip antennas can be reduced, and each whip antenna can be reduced. As a result, the radio waves emitted are not in opposite phase, and an antenna radiation pattern close to a hemisphere can be obtained. (2) There is an effect that it is not affected by the reflected wave due to the rocket coupling portion.

The gist of the present invention is to mount an omnidirectional antenna having an antenna radiation pattern close to a hemispherical surface on a separating surface,
In the embodiment, a whip antenna is shown as an example of an antenna element forming a turnstile antenna, but it is obvious that the same can be applied as long as it has characteristics equivalent to this, and in the present invention, in addition to the whip antenna. Naturally, a satellite in which an omnidirectional antenna of a different type such as a helical antenna transmission line type antenna is mounted on the separation surface of the rocket coupling portion is also included.

[Brief description of drawings]

FIG. 1 is a side view of a conventional satellite equipped with an omnidirectional antenna, FIG. 2 is a radiation pattern of an omnidirectional antenna mounted on a top panel of the artificial satellite of FIG. 1, and FIG. The radiation pattern of the omnidirectional antenna mounted on the bottom panel of the satellite shown in Fig. 4, Fig. 4 is a side view of a conventional satellite having an omnidirectional antenna with a large anti-rocket coupling portion, and Fig. 5 Is a bottom view of FIG. 4, FIG. 6 is a radiation pattern of an omnidirectional antenna mounted on the bottom panel of the artificial satellite of FIG. 4, and FIG. 7 is an omnidirectional antenna radiation according to one embodiment of the present invention. A side view of the artificial satellite having a pattern, FIG. 8 is a bottom view of FIG. 7, and FIG.
It is a radiation pattern of the omnidirectional antenna mounted on the lower panel of the satellite shown in the figure. FIG. 10 is a diagram showing a whip antenna mounted on an artificial satellite, FIG. 11 is a diagram showing the directivity in the horizontal plane of the antenna shown in FIG. 10, and FIG.
Figure 10 shows the directivity in the vertical plane of the antenna shown in Figure 10.
Fig. 13 is a diagram showing the structure of a turnstile antenna composed of multiple whip antennas, and Fig. 14 is a diagram showing changes in the radiation pattern of the water surface diagram when the diameter of the rocket coupling part becomes large in the conventional example. FIG. 15 is a detailed view of the rocket-coupled portion of the present invention. 21: Satellite main body, 22: Solar array paddle, 23: Top panel, 2
4: Bottom panel, 25: Rocket coupling, 26, 27: Whip antenna, 18: Separation plane of rocket coupling.

Claims (1)

[Scope of utility model registration request] 1. A satellite having an antenna device having an antenna radiation pattern close to a hemispherical surface on each of an upper surface and a lower surface, wherein a plurality of turnstile antennas are arranged inside an edge of a separation surface of a coupling portion of a rocket pair. An artificial satellite equipped with an omnidirectional antenna, characterized in that it is provided with a bottom-mounted antenna device in which the antenna elements of are distributed evenly around the central axis of the artificial satellite.