JPH04268803A - Double-reflector antenna system - Google Patents

Abstract

PURPOSE:To reduce the deterioration of an electrical characteristic due to a supporting body, and to reduce the size of an antenna by storing independently a sub reflector according to storage capacity. CONSTITUTION:The antenna system consists of plural posts 6a which project from a holding structure (satellite structure) and hold a main reflector 1 and the sub reflector 2 and connecting members 6b to connect between each post 6a and another, and the connecting members 6b are arranged in an area where no geometrical optical axis going forward from a primary radiator 3 to the sub reflector 2 exists. Besides, the post 6a is made expandable by connecting plural tubular post elements different in their, diameters in a longitudinal direction, and each post element can be fixed with each other by a fastener.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-reflector antenna device for use in space, which is launched by a rocket, for example.

0002

2. Description of the Related Art Conventionally, there has been a device of this type as shown in FIGS. 12 and 13, which are a side view and a front view of the external appearance. This figure is from the Institute of Electronics and Communication Engineers, Antenna Engineering Handbook, p. 300, was shown to Ohmsha on October 30, 1980, and in the figure, 1 is the main reflecting mirror consisting of a paraboloid of revolution with the focal point at point Fa, and 2 is the focal point at points Fa and Fb. 3 is a primary radiator consisting of a conical horn with its phase center located at point Fb; 4 is a support for holding the sub-reflector 2; Note that the dashed-dotted line indicates a path along which electromagnetic waves propagate as a geometric optical optical axis (ray).

[0003] Next, the operation of the conventional Cassegrain antenna described above will be explained using the case of transmission as an example. A spherical wave with the center of curvature at point Fb emitted from the primary radiator 3 is reflected by the sub-reflector 2 and converted into a spherical wave with the center of curvature at point Fa, and then propagates toward the main reflector 1. Then, it is reflected by the main reflecting mirror 1, converted into a plane wave, and radiated into space in the Z-axis direction.

0004

[Problems to be Solved by the Invention] Since the conventional multi-reflector antenna is constructed as described above, reflected waves and diffracted waves are generated by the support that holds the sub-reflector, and the electrical performance is satisfied. The problem was that it was difficult to do so. Furthermore, as the aperture diameter of the main reflecting mirror increases, its dimensions also increase, and there is a problem in that it cannot be applied to space applications, for example, because there is a limit to the capacity that can be loaded onto a rocket.

[0005] This invention was made in order to solve the above-mentioned problems, and it reduces the deterioration of electrical characteristics caused by the support in an antenna with an axially symmetrical structure, and prevents the antenna from being used depending on the storage capacity. It is an object of the present invention to provide a multi-reflector antenna device which can be reduced in size by housing a sub-reflector when used, and which can be easily expanded when used.

[0006]

[Means for Solving the Problem] The first invention provides a holding structure (satellite structure 7), a main reflecting mirror 1 having a focal point Fa, and a main reflecting mirror 1 between the main reflecting mirror 1 and the focal point Fa. A sub-reflector 2 is located coaxially with the reflector 1 and has two focal points: the focal point Fa and a focus Fb located close to the main reflector 1 on the axis of the main reflector 1; a primary radiator 3 located at a focal point Fb close to the reflecting mirror 1; a plurality of mutually parallel supports 6a protruding from the holding structure (satellite structure 7) and holding the main reflecting mirror 1 and the sub-reflecting mirror 2; It consists of a connecting member 6b that connects each support 6a, and the connecting member 6b is arranged in an area where there is no geometrical optical axis (ray) from the primary radiator 3 toward the sub-reflector 2.

[0007] In the second invention, the column 6a is made to be extendable and contractible in the longitudinal direction by connecting a plurality of pipe-shaped column bodies 6aa to 6ac having different diameters, and a stopper 9 is provided between the column bodies 6aa to 6ac. It can be fixed.

[0008]

[Operation] In the present invention, electromagnetic waves emitted from the primary radiator 3 are propagated toward the sub-reflector 3 inside the support body 6, which is composed of the pillar 6a and the connecting member 6b.

[0009] Also, the support 6a has support bodies 6aa to 6ac.
The column body 6a is expanded and contracted in the longitudinal direction by
A to 6ac are fixed by a stopper 9.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 are a side view and a front view showing the appearance of a first embodiment of the present invention, in which transmission is performed using a Cassegrain antenna, which is a type of double-reflector antenna. In the same figure. 1 to 3 are the same as those of the conventional device shown in FIGS. 12 and 13, and 6 is a support that holds the sub-reflector 2 in a predetermined position, and the focal point Fb emitted from the primary radiator 3 is curvatured. In the outer region of the cone where the geometrical optical axis of the central spherical wave exists, a plurality of mutually parallel supports 6a and a plurality of circular connecting members 6b for connecting and fixing the respective supports 6a are provided. It is composed of. A spherical wave with the center of curvature at the focal point Fb emitted from the primary radiator 3 propagates toward the sub-reflector 2 and is reflected,
After being converted into a spherical wave with the center of curvature at a, the main reflecting mirror 1
The wave propagates toward, is reflected, is converted into a plane wave, and is radiated into space in the Z-axis direction. FIG. 3 is an enlarged view showing a part of the support 6 in detail. In the figure, the connecting member 6b is made of a plurality of circular metal members, connects each support 6a, fixes the sub-reflector 2 in a predetermined position, and connects the sub-reflector 2 to the primary radiator 3.
It is placed in an area where there is no geometrical optical axis pointing toward . In this case, the sub-reflector 2 is arranged coaxially with the main reflector 1, and its focal points are two, and one
One focal point is the focal point Fa, and the other focal point is a focal point Fb located on the axis of the main reflecting mirror 1 and close to the main reflecting mirror 1. The primary radiator 3 is located above the focal point Fb.

With the above configuration, in a mirror system in which the distance from the main reflecting mirror 1 to the sub-reflecting mirror 2 is long, deformation such as twisting of the support 6 can be prevented, so that the sub-reflecting mirror 2 can be accurately positioned at a predetermined position. Can be set, from the primary radiator 3 to the secondary reflector 2
Since the influence of reflected waves and diffracted waves by the support body 6 on electromagnetic waves propagating towards can be greatly reduced, deterioration of electrical characteristics can be prevented.

FIGS. 4 and 5 are side and front views showing the external appearance of a second embodiment of the present invention, showing the same antenna type as the embodiment shown in FIGS. 1 and 2. In the same figure, 1 to 3
is the same as the conventional device shown in FIGS. 12 and 13,
6 is a support body, 6aa to 6ac are support bodies, 6am is a protrusion, 7 is a satellite structure as a holding structure, and 8 is a mounting body for holding the primary radiator 3. The support body 6 is a circular structure that connects mutually parallel supports 6a of a plurality of multi-stage cavities that are independently expandable and retractable in the Z-axis direction with respect to the main reflector 1 and the primary radiator 3. and a connecting member 6b. 6 and 7 are enlarged views showing how the support body 6 expands and contracts. In FIG. 6, when the multi-reflector antenna of the present application is not used, the support column 6a can be contracted to make it compact. In FIG. 7, the support column 6a can be extended when using a double reflector antenna. In FIG. 7, 9 is a stopper, 9m is a screw hole, 10 is a fine adjustment device for fine adjustment in the longitudinal direction, 10a is a rotator, and the sub-reflector 2
can be arranged and fixed at a predetermined position, and can have the same effect as the first invention. As shown in FIG. 8, the support column 6a has several pipe-shaped support bodies 6aa to 6a that are fitted together and connected to each other, and the diameter thereof gradually decreases.
Consists of c. Three pillars 6a are positioned at equal angles, extend parallel to each other, and are telescopic. For example, as shown in FIG. 8, the fine adjustment device 10 has a rotator 10a having a threaded portion on its inner surface, and a protrusion 6a of a support element 6aa on the base side.
The support element 6aa can be moved forward and backward by rotating the fine adjustment device 10, and can be finely adjusted. Further, the stopper 9 has a screw hole 9m formed in the ring-shaped connecting member 6b.
Each internal support element 6aa to 6ac is screwed in at the tip.
Consists of a bolt that is pressed to prevent it from coming off. Note that the tips of each of the support columns 6aa to 6ac are fitted into the connecting member 6b and integrated. In addition, the sub-reflector 2 is attached to the mounting body 8.
It is fixed to the support column 6a via.

As can be seen from FIG. 6, the dimensions of the antenna become smaller. For example, when applied to a space antenna launched by a rocket, if the dimensions when the sub-reflector 2 is housed satisfy the capacity that can be loaded on the rocket. This makes it possible to realize larger antennas than before. Also, pillar 6
b can be expanded and contracted independently of the main reflector 1 and the primary radiator 3, so the sub-reflector 2 can be easily arranged in an antenna format in which the main reflector 1 is expanded. Other operations operate similarly to the first invention and have similar effects.

[0014] In the embodiments shown above, the case of transmission has been explained as an example, but it also works reversibly for reception, and is equally effective for the purpose of the present invention. Further, although a conical horn is used as the primary radiator, a corrugated horn or other type of horn can also have the same effect as the above embodiment. Furthermore, although the case of a Cassegrain antenna is shown as the double-reflector antenna, a Gregorian antenna or other type of radiation system can have the same effect as the above embodiment. Further, the connecting member 6b may have a hexagonal shape as shown in FIG. 9, an elliptical shape as shown in FIG. 10, or a clover shape as shown in FIG. 11.

[0015]

As described above, according to the first invention, the connecting member 6a of the support body 6 is connected to the secondary reflector 2 from the primary radiator 3.
Since it is arranged in a region where there is no geometrical optical axis directed toward , the generation of reflected waves and diffracted waves by the connecting member 6a of the support 6 is reduced, which has the effect of reducing deterioration of the electrical characteristics of the antenna. .

Further, according to the second invention, since the support column 6a is made longitudinally expandable and retractable, the size can be reduced by storing the sub-reflector when not in use, depending on the storage capacity. has the advantage of being easy to deploy.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the appearance of a double-reflector antenna device according to an embodiment of the first invention.

FIG. 2 is a front view showing the appearance of a double-reflector antenna device according to an embodiment of the first invention.

FIG. 3 is an enlarged external view of a support portion according to an embodiment of the first invention.

FIG. 4 is a side view showing the appearance of a double-reflector antenna device according to an embodiment of the second invention.

FIG. 5 is a front view showing the appearance of a double-reflector antenna device according to an embodiment of the second invention.

FIG. 6 is an external view of the support body according to an embodiment of the second invention when it is housed.

FIG. 7 is an external view of the expanded support according to an embodiment of the second invention.

FIG. 8 is a structural diagram of a double-reflector antenna device according to an embodiment of the second invention.

FIG. 9 is an external view of a connecting member according to another embodiment of the present invention, which has a hexagonal shape.

FIG. 10 is an external view of a connecting member according to another embodiment of the present invention, which has an elliptical shape.

FIG. 11 is an external view of a connecting member according to another embodiment of the present invention, which is clover-shaped.

FIG. 12 is a side view showing the appearance of a conventional double-reflector antenna.

FIG. 13 is a front view showing the appearance of a conventional double-reflector antenna.

[Explanation of symbols]

1 Main reflecting mirror 2 Secondary reflector 3 Primary radiator 6 Support 6a Post 6b Connecting member 6aa~6ac　Strut body 7 Satellite structure 9 Stopper

Claims (2)

[Claims] Claims: 1. A holding structure, a main reflecting mirror having a focal point at a point Fa, located between the main reflecting mirror and the focal point Fa, and coaxially with the main reflecting mirror; Fa and a focal point Fb located on the axis of the main reflecting mirror and close to the main reflecting mirror; and a primary radiator located at the focal point Fb close to the main reflecting mirror. and a plurality of mutually parallel pillars that protrude from the holding structure and hold the main reflecting mirror and the sub-reflecting mirror;
A double-reflector antenna comprising a connecting member connecting each support, wherein the connecting member is arranged in an area where there is no geometrical optical axis extending from the primary radiator to the sub-reflector. Device. 2. Each of the above-mentioned columns is made to be freely expandable and contractable in the longitudinal direction by connecting a plurality of pipe-shaped column bodies having different diameters, and each of the above-mentioned column bodies can be fixed with a stopper. The double-reflector antenna device according to claim 1.