JPH0722835A - Antenna reflector - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent the shape of the reflecting mirror surface from harmfully deforming even if the temperature in the plane of the reflecting mirror surface is affected by the temperature change in an orbit on the reflecting antenna surface for space use. [Structure] A shell forming a reflecting mirror surface is divided into a plurality of pieces, and the shells are combined and rigidly reinforced with ribs to form one antenna reflecting mirror surface. [Effect] Even if a temperature distribution occurs in the plane, it is kept only in the divided shells, so that the deformation of the antenna reflector as a whole is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflector for an aperture antenna mounted on space equipment such as artificial satellites.

[0002]

2. Description of the Related Art Antenna reflectors for space use are required to be lightweight and highly rigid, and to have the ability to maintain the required reflector surface shape against temperature changes in the operating orbit. Figure 10
Shows an example of a conventional antenna reflecting mirror. In the figure, 1 is a honeycomb sandwich shell (hereinafter referred to as shell) that constitutes a reflecting mirror surface, and 2 is a honeycomb sandwich for supporting the same from the back surface to increase the rigidity. A rib-shaped support structure (hereinafter referred to as a rib) 3 of the plate is a joining member that adhesively joins the shell and the rib. Antenna reflector
In orbit, it is exposed to a wide temperature range from about -180 degrees to about +100 degrees. In particular, when the shadow of another device mounted on the satellite falls on the antenna reflecting mirror surface, a temperature difference occurs in the shell surface, and the amount of expansion at each part of the shell differs, resulting in large deformation. In contrast,
In the conventional antenna reflecting mirror surface, the following measures are taken. That is, the thermal expansion coefficient of the entire antenna reflecting mirror surface is made uniform by using the honeycomb sandwich plate having the same structure for the shell and the rib. Also, a low thermal expansion material such as carbon fiber reinforced plastic (hereinafter referred to as CFRP) or aramid fiber reinforced plastic (hereinafter referred to as KFRP) is used for the surface material, and ultra thin aluminum or KFRP or Nomex is used for the honeycomb core material. Then, the absolute value of the coefficient of thermal expansion of the shell and the rib made of the honeycomb sandwich plate is made as small as possible to suppress the deformation of the antenna reflector against the temperature environment on the orbit. However, in an actual reflecting mirror, even if the coefficient of thermal expansion is ideally set to zero, the limit is actually 0.5 to 1 ppm. Furthermore, for thermal control, a white paint, etc. is applied to the reflective mirror surface side of the shell, and the coefficient of thermal expansion is larger than that of the sandwich alone.Therefore, the shadowed area when there is a temperature difference in the reflective mirror surface. Has a low temperature and has a smaller elongation than other portions, which causes the shell shape to be deformed into a distorted shape.

[0003]

In the conventional antenna reflecting mirror surface, when there is a temperature difference in the reflecting mirror surface as described above,
Part of the deformation of the reflector surface causes the entire shell of the reflector surface to be deformed. For antennas that use high frequency bands such as the Ka band and antennas that use shaped beams, such shell deformation of the reflector causes Performance will be reduced. In order to solve this problem, measures have been taken such as attaching an aperture cover to prevent direct shadows from reflecting mirror surfaces, but this inevitably leads to deterioration of electrical performance and further increases weight.

The present invention has been made in order to solve the above problems, and does not cause deterioration of the shape accuracy of the antenna reflecting mirror surface even if a temperature difference occurs in the surface of the reflecting mirror surface shell. The purpose is to obtain a mirror surface.

[0005]

The antenna reflecting mirror surface according to the present invention is such that a shell is divided into a plurality of parts and the ribs are jointly reinforced so that one reflecting mirror surface is formed as a whole. The width is adjusted and manufactured so that there is no problem in performance at the frequency of the radio wave used.

[0006]

For example, in the adjacent end faces of a plurality of divided shells, the end faces of the shell are formed in a wedge shape and are overlapped with the adjacent shells. In this case, if a shadow falls in the surface of the shell that constitutes the reflector surface and a temperature difference occurs,
The shaded area will have a relatively small amount of expansion or contraction compared to the areas on other days. The deformation caused by the shadow affects only that shell, not the other adjacent shells. Therefore, the deformation of the antenna reflector as a whole is small. Further, since the end face is formed in a wedge shape, even if the shells forming the reflecting mirror surface are relatively spaced apart, a wedge surface exists as a surface forming the reflecting mirror surface, and the deviation from the reflecting mirror surface is small. Further, even if the gaps come into contact with each other at a reduced distance, the wedge surface does not cause damage because the force escapes out of the plane.

For example, at the adjacent end faces of a plurality of divided shells, the surface forming the antenna reflecting mirror surface is extended and overlapped with the adjacent shells. At this time, a part of the surface is dented by the thickness of the surface on the overlapping side.
In this case, there is only a step difference in the antenna reflection surface and there is no space. Therefore, the shell interval can be set so as not to come into contact with each other due to temperature change. In this case, when a shadow is cast on the surface of the shell that constitutes the reflecting mirror surface and a temperature difference occurs, the shadowed portion has a relatively larger elongation than the other exposed portions. It will be small or shrink. The deformation caused by the shadow affects only that shell, not the other adjacent shells. Therefore, the deformation of the antenna reflector as a whole is small. In addition, since the skin that constitutes the antenna reflecting mirror surface is extended and overlapped on the next shell, even if the spacing between the shells that constitute the reflecting mirror surface is relatively wide, the reflecting mirror surface forming surface is the reflecting mirror surface. The deviation from is small.

Further, for example, in an antenna reflecting mirror surface in which one reflecting mirror surface is composed of a plurality of shells which are formed by combining adjacent end surfaces of shells in a T shape, the adjacent end surfaces of the shells are formed into a T shape and combined. Therefore, at the time of manufacturing, it can be used for adjusting the gap by contacting it, and even if the gap between the shells changes and the contact becomes large, it is caused by local deformation of the neck portion of the T-shape. It can be made small so that the effect can be almost ignored. Therefore, even if a temperature distribution occurs in the surface of the shell that forms the reflecting mirror surface, the shaded area has a relatively small amount of expansion or shrinks compared to the areas exposed to other days. Even so, the transformation affects only the shadowed shell, not the other adjacent shells. Therefore, the deformation of the antenna reflector as a whole is small.

[0009]

EXAMPLES Example 1. FIG. 1 is a diagram showing an embodiment of an antenna reflecting mirror according to the first claim of the present invention.
In the figure, 1 is a shell formed so as to form one reflecting mirror surface, 2 is a rib for connecting the plurality of shells and reinforcing rigidity, and 3 is a connecting member. FIG. 2 is a cross-sectional view of the antenna reflecting mirror portion, showing a state of coupling by the shell 1, the ribs 2, and the coupling member 3 and a state of a wedge-shaped end face of adjacent shells. For example, when a shadow is cast on one of the plurality of shells forming the reflecting mirror surface, the temperature of that portion becomes lower than that of the other portion.
For this reason, this part has a smaller elongation than other parts or contracts, causing distorted deformation of the shell. However, the transformation is limited to that shell,
Other shells are unaffected. FIG. 3 is a diagram for explaining that the deformation of one shell does not reach the other.

Embodiment 2. A single surface of the shell forming the reflecting mirror surface may be molded into a wedge shape to adjust the interval for manufacturing.
FIG. 4 is a cross-sectional view of the antenna reflecting mirror portion, showing a state of coupling by the shell 1, the ribs 2, and the coupling member 3 and a state of the wedge-shaped end faces of the adjacent shells. For example, when a shadow is cast on one of the plurality of shells forming the reflecting mirror surface, the temperature of that portion becomes lower than that of the other portion. For this reason, this part has a smaller elongation than other parts or contracts, causing distorted deformation of the shell. However, the deformation is limited to that shell and other shells are unaffected. Also,
Even if the spacing between the shells differs due to the difference in the coefficient of thermal expansion between the ribs and the shell, the wedge surface forms a part of the reflector surface when it is opened, and when it contracts and contracts, it follows the wedge surface. Because the power is distorted, it does not lead to destruction. 5 and 6 are views for explaining the action of the wedge surface of the shell.

Embodiment 3. It is also possible to extend the skin forming the reflecting mirror surface of the shell and overlap it with the adjacent shell, and in the overlapping portion of the adjacent shell, the surface may be recessed by the thickness of the skin. FIG. 7 is a cross-sectional view of the antenna reflecting mirror portion, showing a state in which the shell 1, the ribs 2, and the coupling member 3 are coupled, and a state in which the extended skins of adjacent shells are stacked. For example, when a shadow is cast on one of the plurality of shells forming the reflecting mirror surface, the temperature of that portion becomes lower than that of the other portion. For this reason, this part has a smaller elongation than other parts or contracts, causing distorted deformation of the shell. However, the deformation is limited to that shell and other shells are unaffected. Further, even if the spacing between the shells is different due to the difference in the coefficient of thermal expansion between the rib and the shell, the reflecting mirror surface is constituted by the skin, so that the spacing is not affected and the performance hardly changes. FIG. 8: is a figure explaining the effect | action of the wedge surface of the part which the skin of the shell overlapped.

Embodiment 4. In order to adjust the gap between the reflecting mirror surfaces at the time of manufacture, a T-shaped portion may be provided on a part of the adjacent end faces of the shell forming the reflecting mirror surface to serve as a guide. This facilitates adjustment of the gap. In this case, when a temperature distribution is generated in the plane of the shell, the shell deforms but does not affect other shells. Also, if the space between the shells is closed, the contact part will be attached, but since the thin neck part of the T-shaped molding part locally deforms, there is almost no effect on the deformation of the entire shell, and the reflector The overall deformation is small. This action is shown in FIG.

[0013]

According to the antenna reflecting mirror of the present invention, even if a temperature difference occurs in the reflecting mirror surface, the antenna reflecting mirror as a whole can maintain a desired mirror surface shape accuracy without causing harmful deformation. It can be achieved without increasing the weight by making large-scale devises such as the opening surface cover.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a partial cross section of an antenna reflecting mirror according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of the operation of the antenna reflector of one embodiment of the present invention.

FIG. 4 is a diagram showing a partial cross section of an antenna reflector according to a second embodiment of the present invention.

FIG. 5 is a diagram for explaining the operation of the wedge-shaped end face in the second embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the wedge-shaped end face in the second embodiment of the present invention.

FIG. 7 is a diagram showing a partial cross section of an antenna reflecting mirror according to a third embodiment of the present invention.

FIG. 8 is a view for explaining the operation of overlapping the skins of the shell end surface in the third embodiment of the present invention.

FIG. 9 is a diagram for explaining the operation of the antenna reflecting mirror in the fourth embodiment of the present invention.

FIG. 10 is a diagram illustrating a conventional antenna reflector.

[Explanation of symbols]

 1 Shell 2 Rib 3 Coupling member 4 Wedge-shaped shell end 5 Shell deformed by temperature difference 6 Extension of the skin that constitutes the reflecting mirror surface 7 Shell end indented only by the thickness of the reflecting mirror surface 8 T-shaped shell end Department

Claims (4)

[Claims] 1. A sandwich structure having a composite material as a skin, one surface of which is composed of a shell molded to form an antenna reflecting mirror surface and a sandwich structure plate having a composite material as a skin material. , An antenna reflector comprising a rib for stiffening the shell and a composite material laminated material, and a coupling member for adhering the shell and the rib, wherein the shell is divided into a plurality and one reflector is configured. An antenna reflecting mirror, characterized in that it is supported by integral ribs so as to maintain mutual positions, and that a plurality of shells are provided with a gap. 2. The antenna reflector according to claim 1, wherein the end faces of the plurality of shells are formed in a wedge shape and overlapped with each other to provide a space between the plurality of shells. 3. The antenna reflecting mirror according to claim 1, wherein a plurality of shells are provided by extending and overlapping outer skins constituting the antenna reflecting mirror. 4. The antenna reflecting mirror according to claim 1, wherein the plurality of shells are provided with a space by forming end faces of the plurality of shells so as to interleave each other.