JPH0712124B2 - Antenna device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antenna device used in a satellite communication earth station for simultaneously accessing two satellites.

[Conventional technology]

FIG. 5 is a schematic configuration diagram showing a conventional antenna device shown in, for example, the Antenna Engineering Handbook (edited by the Institute of Electronics and Communication Engineers, published by Ohmsha). In the figure, 1a and 1b correspond to two satellites, respectively. The power supply section of this antenna device provided,
Reference numerals 2a and 2b are primary radiators that form the power feeding portions 1a and 1b, 3 is a sub-reflecting mirror that reflects the electromagnetic waves emitted from the primary radiators 2a and 2b, and 4 is the electromagnetic waves reflected by the sub-reflecting mirror 3. The main reflecting mirrors 5a and 5b which reflect are the satellite directions of the two satellites to which the electromagnetic waves reflected by the main reflecting mirror 4 are sent.

In addition, the positions F ₁ and F _{2 of the} primary radiators 2a and 2b and the direction of the central axis The electromagnetic waves emitted from these are respectively reflected by the subreflector 3,
It is reflected by the main reflecting mirror 4, radiated in the corresponding satellite directions 5a and 5b, and determined so as to have the highest gain.

Next, the operation will be described. The electromagnetic wave radiated from the primary radiator 2a provided in the power feeding unit 1a is reflected by the sub-reflecting mirror 3 and the main reflecting mirror 4, and then radiated in the satellite direction 5a of one satellite which is simultaneously accessed. Similarly, the electromagnetic wave emitted from the primary radiator 2b provided in the power feeding unit 1b is emitted in the satellite direction 5b of the other satellite. Therefore, by using this antenna device, two satellites can be simultaneously accessed in order to radiate electromagnetic waves independently in the satellite directions 5a and 5b of the two satellites.

FIG. 6 is an explanatory diagram for explaining the two satellite directions 5a and 5b. In the figure, the ξ-axis and η-axis are coordinate systems representing the angles of the azimuth direction and the elevation direction, respectively.
ξ _o and η _o are ξ and η coordinates representing the directions of the centers of the two satellites, 5a and 5b represent the satellite directions of the two satellites, and 6 represents the geostationary satellite orbital plane. Also, α is η
The angle between the axis and the orbital plane 6 of the satellite, θ _e is the two satellite directions 5
It is the separation angle from a and 5b. Here, when the position of the earth station changes, ξ _o , η _o , α, and θ _e generally change. Of these, changes in ξ _o and η _o can be dealt with by setting the direction of the antenna device as a whole, but changes in α and θ _e change the positions F ₁ , F ₂ and directions of the primary radiators 2a, 2b of the antenna device. Need to be addressed by changing Also, α,
As another method of reacting to the change in θ _e , there is a method in which the entire antenna device is tilted by α, paying attention to the small change in θ _e .

[Problems to be Solved by the Invention]

Since the conventional antenna device is configured as described above, when it is used for earth stations at different positions, the position and direction of the primary radiator with respect to the ground surface are changed by any of the above methods, so it is placed on the ground. In addition, a flexible waveguide for connecting the transmitter / receiver of the earth station and the primary radiators 2a and 2b is required, which causes a problem such as a large loss.

The present invention has been made to solve the above problems, even when used in earth stations at different positions,
An object is to obtain an antenna device in which the position and direction of the primary radiator with respect to the ground surface are the same.

[Means for Solving the Problems]

In the antenna device according to the present invention, the two feeding parts are each configured by one primary radiator and one plane mirror, and when installed on the ground, the central axes of the two primary radiators are parallel to the ground surface, and The positions and normal directions of the plane mirrors are set so that the heights from the ground surface to the respective primary radiators are equal to each other.

[Action]

By adjusting the position and the direction of the normal line of the plane mirror of each power feeding unit in the present invention, two primary radiators are arranged so that their central axes are parallel to the ground plane and their heights from the ground plane are equal to each other. Is arranged so that the both primary radiators and the transmitter / receiver of the satellite communication earth station can be connected by a linear waveguide.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1a and 1b are feeding parts, 2a and 2b are primary radiators, 3 is a sub-reflecting mirror, 4 is a main reflecting mirror, 5a and 5b are satellite directions, and FIG. Since these are the same as or equivalent to those, detailed description will be omitted. Also, 7a, 7
b is a plane mirror whose position and normal direction can be adjusted, reflects the electromagnetic wave from the primary radiator 2a or 2b, and constitutes the power feeding unit 1a or 1b together with the primary radiator 2a or 2b. .

Next, the operation will be described. The electromagnetic wave emitted from the primary radiator 2a provided in the power feeding unit 1a is reflected by the plane mirror 7a in the primary radiator 2a and reaches the sub-reflecting mirror 3. This electromagnetic wave is reflected by the sub-reflecting mirror 3 and then further reflected by the main reflecting mirror 4, and is radiated in the satellite direction 5a of one of the simultaneously accessed satellites. In that case, the position and the radiation direction of the plane mirror 7a are set so that the radiation direction of the electromagnetic waves coincides with the satellite direction 5a. Similarly, the electromagnetic wave radiated from the primary radiator 2b of the power feeding unit 1b is reflected by the plane mirror 7b, further reflected by the sub-reflecting mirror 3 and the main reflecting mirror 4, and then radiated in the satellite direction 5b of the other satellite. . Also in that case, the position and the normal direction of the plane mirror 7b are set so that the radiation direction of the electromagnetic waves coincides with the satellite direction 5b.

FIG. 2 is an explanatory view for explaining the method of setting the position and normal direction of the plane mirror 7a (7b). In the figure, 8 is the ground plane on which this antenna device is installed, 9 is the transceiver of the earth station, and 10a (10b) is the plane mirror 7a (7b) of the primary radiator 2a (2b).
It is an image by. Also, Is a unit vector perpendicular to the ground plane 8, Represents the direction of the central axis of the given primary radiator 2a (2b) Unit vector orthogonal to Is a vector. Furthermore, F _i , (Corresponding to each satellite when i = 1, 2) represent the same position and unit vector as those of the conventional antenna device shown in FIG. 5, and S _i and n _i are plane mirrors 7a.
Position and unit normal vector of (7b), P _i is the primary radiator
It shows the position of 2a (2b). At this time, the plane mirror 7a
The unit normal vector n _i in (7b) is Then, the position S _i is selected so that the length of the foot lowered from the position S _i to the ground surface 8 becomes H, and the position P ₁ of the primary radiator 2a (2b) is changed from the position S _i to the −k direction. If the point is advanced by │S _i F _i │, the image 10a (10b) by the plane mirror 7a (7b) of the primary radiator 2a (2b) is the conventional primary radiator 2a shown in FIG.
It overlaps with (2b) and has the same electrical performance as the conventional case. At this time, since the height of the primary radiator 2a (2b) from the ground plane 8 is always H, only the transceiver 9 having an input / output terminal at the height of H from the ground plane 8 and the straight waveguide. You can connect with.

Here, in the embodiment shown in FIG. 1, since the central axes of the primary radiators 2a and 2b are parallel to the ground surface 8, the primary radiators 2a and 2b are
A part of the electromagnetic wave radiated from the component that does not hit the plane mirrors 7a and 7b, a so-called spillover component, is part of the ground surface 8
It may be radiated into the interior, which may interfere with the ground line and interfere with communication.

FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention, in which the above-mentioned problematic components are scattered in directions other than the ground plane and the satellite orbital plane where interference is a problem. .

Hereinafter, this embodiment will be described with reference to the drawings. In FIG. 3, reference numerals 11a and 11b denote metal portions having curved surfaces provided around the plane mirrors 7a and 7b, and the others are the same as those in FIG. Of the electromagnetic waves emitted from the primary radiators 2a and 2b, unnecessary components indicated by broken lines are reflected by the metal part 11a or 11b. Here, the curved surfaces of the metal parts 11a and 11b are designed so that the reflected electromagnetic waves pass between the main reflecting mirror 4 and the sub-reflecting mirror 3 and are scattered in the zenith direction as shown in the figure. There is.

FIG. 4 shows a plane mirror 7a provided with such a metal part 11a (11b).
It is explanatory drawing which shows the specific example of (7b), (a) of the figure is the top view, (b) is a front view, (c) is a side view, (d) is its usage explanatory drawing. In this example, as shown in the figure (b), the metal part 11a whose rising becomes larger as it goes to one side of the plane mirror 7a (7b), that is, to the right in the figure (b). (11b) is provided, and when this plane mirror 7a (7b) is used, a large rising portion of the metal part 11a (11b) is arranged away from the ground surface 8 as shown in FIG. It

〔The invention's effect〕

As described above, according to the present invention, a plane mirror is provided in each of the two feeding portions, and the position and the normal direction of the plane mirror are such that the central axis of the primary radiator of each feeding portion is parallel to the ground surface, and Since the heights from the ground surface to the primary radiators are set to be equal to each other, connect each primary radiator to the transmitter / receiver of the satellite communication earth station with a straight waveguide with low loss. This makes it possible to obtain a high-performance antenna device, and because the primary radiator is placed at a predetermined height in parallel with the ground surface, the primary radiator can be designed simply and with high accuracy. There is.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an antenna device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a method of setting a plane mirror thereof, and FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention,
FIG. 4 is an explanatory diagram showing a concrete example of the plane mirror, FIG. 5 is a schematic configuration diagram showing a conventional antenna device, and FIG. 6 is an explanatory diagram for explaining satellite directions of two satellites. 1a and 1b are feeding parts, 2a and 2b are primary radiators, 3 is a sub-reflector, and 4
Is a main reflector, 5a and 5b are satellite directions, 7a and 7b are plane mirrors, 8 is a ground surface, and 11a and 11b are metal parts. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshikazu Hori 1-1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Tomoaki Tanaka 1-1-6 Uchisai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (1)

[Claims] 1. An antenna device for reflecting electromagnetic waves from two power feeding units by a sub-reflecting mirror and a main reflecting mirror, sending the electromagnetic waves to different satellite directions, and accessing two satellites at the same time. The antenna device includes one primary radiator that radiates the electromagnetic wave and one plane mirror that can adjust the position and the normal direction and that reflects the electromagnetic wave emitted from the primary radiator, and the antenna device is placed on the ground surface. When installed, the primary radiators are arranged such that their central axes are parallel to the ground plane and the heights from the ground plane are equal to each other, and the positions and normal directions of the plane mirrors are arranged. Is set so that the direction of the electromagnetic wave transmitted from the main reflecting mirror coincides with the satellite direction of each satellite.