JPS63173404A - Multi-beam antenna - Google Patents

Abstract

PURPOSE:To improve the efficiency and to reduce the antenna axis by providing a main reflection mirror formed by bonding plural partial reflection mirrors being parts of plural paraboloids of rotation whose focii differ while a different turning center axis is used and providing a primary radiator radiating a radio wave to the main reflection mirror so as to overlap the part of the radiated region of the partial reflection mirror. CONSTITUTION:The main reflection mirror 1 is formed by bonding a partial reflection mirror A' being a part of the paraboloid of rotation A and a partial reflection mirror B' being a part of the paraboloid of rotation B while the turning center axes (a), (b) are directed in different directions. The primary radiators 21, 22 apply radio wave radiation so as to overlap parts of the radiated region of the corresponding partial reflection mirror. In this case, each radiation region is regarded as the independent rotating paraboloid reflection mirror. Thus, the shape of the curved face of the overlapped part of the radiation region A'' is made close to the curved shape of the rotation paraboloid A and the curved face of the overlapped part of the radiation region B'' is made close to the curved shape of the rotation paraboloid B. Moreover, the antenna axial length is reduced by applying indirect radiation between the main reflection mirror 1 and the focal points Fa, Fb of the primary radiators 21, 22 via a flat reflection plate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a multi-beam antenna that enables simultaneous communication with a plurality of satellites in a geostationary orbit using one antenna.

(Prior Art) A conventional multi-beam antenna has a plurality of (for example, three) primary radiators 21, 22,
The primary radiators 21, 22, and 23 are composed of a paraboloid of revolution reflecting mirror 5 that reflects the radio waves emitted by these primary radiators in different directions. It is arranged near the focal point F at an appropriate distance of Np1.

Note that, as illustrated for the primary radiator 21, each primary radiator is provided with a feeding section 6 and a low noise amplifier 7 so as to extend in the axial direction of the antenna shaft.

(Problems to be Solved by the Invention) However, in the conventional multi-beam antenna shown in FIG. 21, 22, 23
It is necessary to widen the arrangement interval, but then the arrangement position will be separated from the focal point F, which will cause disturbance in the wavefront at the aperture surface of the paraboloid of revolution reflector 5 and reduce the antenna gain.

Furthermore, since the feed section 6 and the low noise amplifier 7 that are directly connected to the primary radiator 21 and the like extend in the axial direction of the antenna axis, there is a problem that the axial length of the antenna axis becomes long.

The present invention was devised in view of these conventional problems, and its purpose is to increase the deviation of the radiation beam without increasing the disturbance of the wavefront at the aperture surface, that is, to improve the antenna efficiency. Another object of the present invention is to provide a multi-beam antenna in which the axial length of the antenna axis can be shortened.

(Means for Solving the Problems) In order to achieve the above object, the multi-beam antenna of the present invention has the following configuration.

That is, in the multi-beam antenna of the present invention, a plurality of partial reflecting mirrors each consisting of a part of a plurality of paraboloids of revolution having different focal positions are arranged so that the central axes of rotation of the plurality of paraboloids of revolution are mutually aligned. one main reflecting mirror joined with the main reflecting mirror oriented in different directions; the main reflecting mirror so that the corresponding partial reflecting mirror of the main reflecting mirror and a part of the adjacent partial reflecting mirror become an irradiation area; be arranged at each of the plurality of focal positions to emit radio waves directly to the mirror, or indirectly through one plane reflecting plate interposed between the main reflecting mirror and the plurality of focal positions. a plurality of primary radiators arranged at each of a plurality of mirror image point positions symmetrical to each of the plurality of focal positions with respect to the plane reflection plate to radiate radio waves to the main reflection mirror; It is a multi-beam antenna.

(Function) Next, the function of the multi-beam antenna of the present invention having the above configuration will be explained.

For example, one main reflecting mirror has a paraboloid of revolution A (focal position F
,, a partial reflecting mirror A' consisting of a part of the rotation center axis a),
Paraboloid of revolution B (focal position Fb, central axis of rotation b) σ Partially reflecting mirror B' consisting of a part It is formed by joining in a state where it is oriented in the direction.

In other words, in the main reflecting mirror, the partial reflecting mirror A' is centered around the rotation center axis a.
The partial reflecting mirror B' reflects and radiates radio waves in a direction parallel to the rotation center axis a,
Since the two beams are directed in different directions, the main reflecting mirror emits radio waves in two different directions.

On the other hand, there are two ways to arrange the primary radiators X and Y, but in either case, the primary radiators Radio waves are radiated to the main reflecting mirror so as to correspond to each other, that is, the main reflecting mirror irradiates the radio waves emitted from each of the two primary radiators X and Y directly or Two irradiation areas are formed that receive the light indirectly through the plane reflector, and there is an appropriate overlap between the two irradiation areas.

Here, the gist of the present invention is to form a plurality of irradiation areas on one main reflecting mirror, with appropriate overlapping parts between adjacent irradiation areas, but each irradiation area rotates independently of each other. The idea is to make it possible to consider it as a parabolic reflector. In the example above, this means that the partial reflector B', which is the overlapped part with the partial reflector A',
It suffices if the curved surface shape in the irradiation area A'', which consists of a part of It is sufficient that the curved surface shape in the irradiation region B'' is a part of the paraboloid of revolution B as a whole. To do this, the curved surface shape of the overlapping portion in the irradiation area A'' must be very close to the curved surface shape of the paraboloid of revolution A, and the curved surface shape of the overlapping portion in the irradiation area B'' must be very close to the curved surface shape of the paraboloid of revolution B. There is a need to.

This can be achieved by appropriately selecting and setting the distance between the two primary radiators X and Y, and the irradiation area A
The curved shape of the main reflecting mirror within ``approximately matches the curved surface shape of paraboloid of revolution A'', and the curved surface shape of the main reflecting mirror within irradiation area B'' approximately corresponds to the curved surface shape of paraboloid of revolution B. Can be matched.

Therefore, each of the plurality of irradiation areas in the main reflecting mirror emits radio waves in different directions, parallel to the central axis of rotation of a predetermined paraboloid of rotation that gives the curved shape of the irradiation area. be able to. At this time, the curved shape of the irradiation area A'' can be considered to be approximately equal to the paraboloid of revolution A, and since the deviation angle of the radiation beam is determined by the curved shape of the irradiation area A'', the deviation angle can be increased. Also, the disturbance of the wavefront at the aperture plane can be significantly reduced, thus improving the antenna efficiency.

In addition, when irradiating the main reflector from the primary radiator, if irradiation is done directly, each primary radiator will be placed facing the main reflector, so the antenna axis length will remain the same as before. becomes longer.

However, if we choose to irradiate indirectly through one plane reflector, the plane reflector will be placed so as to face the main reflector, and each primary radiator will reflect the plane in the direction around the antenna axis. Since the antenna is arranged so that the irradiated radio waves are obliquely incident on the plate, the axial length of the antenna can be shortened.

As explained above, according to the multi-beam antenna of the present invention, the plurality of irradiation areas of one main reflecting mirror are
Although there is an appropriate overlap between adjacent irradiation areas, the curved surface shape of each irradiation area is a paraboloid of rotation that is approximately equal to the curved surface shape of the irradiation area when one main reflecting mirror and one irradiation area are used. Since it can be an object surface, each irradiation area can be regarded as a mutually independent paraboloid of revolution reflecting mirror. Therefore, according to the present invention, a highly efficient multi-beam antenna can be constructed.

Further, by indirectly transmitting the irradiated radio waves from the plurality of primary radiators to the main reflecting mirror via one plane reflecting plate, there is an effect that the antenna axial length can be shortened.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a multi-beam antenna according to a first embodiment of the present invention. The multi-beam antenna according to the first embodiment consists of a main reflector 1 and two primary radiators 21 and 22. It is a 2 beam antenna.

The main reflecting mirror 1 includes a partial reflecting mirror 31 consisting of a part of a paraboloid of revolution A and a partial reflecting mirror 32 consisting of a part of a paraboloid of revolution B.
are joined along the joint boundary line 2 so that the rotation center axis 41 of the paraboloid of revolution A and the rotation center axis 42 of the paraboloid of revolution B intersect.

Note that the rotation center axis 41 of the paraboloid of rotation A and the rotation center axis 42 of the rotation paraboloid B are respectively the center axis 5 of the antenna.
The focal point F, which is inclined at an angle δ/2 with respect to 0 and located on the axis thereof, and the focal point Fb are separated by a distance of 2d.

On the other hand, the primary radiator 21 is placed at the focal point F1 on the rotation center axis 41, and the primary radiator 22 is placed at the focus Fb on the rotation center axis 42, and the primary radiator 21 is partially reflective. The primary radiator 22 mainly irradiates the irradiation area A'' on the mirror 31 side, and the irradiation area B'' on the partially reflecting mirror 32 side. Note that there is an overlapping portion (A) between the irradiation areas A'' and B'' at the joining boundary line 2.

Here, the irradiation area A'' is between the partial reflecting mirror 31 and the partial reflecting mirror 3.
The irradiation area B" consists of a partial reflecting mirror 32 and a part of the partial reflecting mirror 31, but the distance 2d between the placement positions of the primary radiator 21 and the primary radiator 22 is appropriately selected and set. By doing so, the curved surface of the irradiation area A'' can be made to approximately match the paraboloid of revolution A, and the curved surface of the irradiation area B'' can be made to approximately match the paraboloid of revolution B.

With this setting, the light ray emitted from the focal point F becomes a light ray almost parallel to the central axis 41 of the paraboloid of revolution A after being reflected by the irradiation area A'' of the main reflecting mirror 1 (beam A
radial direction).

On the other hand, the light beam emitted from the focal point Fb becomes a light beam almost parallel to the central axis 42 of the paraboloid of revolution B after being reflected by the irradiation area B of the main reflecting mirror 1 (beam B radiation direction), that is,
The radio waves radiated from the primary radiators 21 and 22 are radiated in the direction of the rotation center axis 41 and 42, respectively.

In this way, a two-beam antenna can be realized.

Next, FIG. 2 shows a multi-beam antenna according to a second embodiment of the present invention.
0, the primary radiator and the corresponding partial reflector were on the same side, whereas in this second embodiment, the primary radiator and the corresponding partial reflector were on the same side with respect to the central axis 50. are set on opposite sides of each other.

That is, the partial reflecting mirror 31 corresponding to the primary radiator 21 consists of a part of the paraboloid of revolution B, and the partial reflecting mirror 32 corresponding to the primary radiator 22 consists of a part of the paraboloid of revolution A. The rest is the same as the first embodiment.

Next, FIG. 3 shows a multi-beam antenna according to a third embodiment of the present invention. In this third embodiment, in the second embodiment, a main reflecting mirror 1, two focal points F, and A flat reflector 4 is arranged between the primary radiators 21 and 2.
2 is arranged facing the plane reflection plate 4 at the focal point F and the mirror image point of the plane reflection plate 4 at the focal point Fb.

With this configuration, the radio waves emitted from the primary radiators 21 and 22 are reflected by the flat reflector 4 and then directed toward the main reflector 1, and then reflected by the main reflector 1 and sent in two different directions. radiated.

The plane reflector 4 simply serves to bend the path of radio waves, and the principle of operation as a multi-beam antenna is the same as in the first embodiment. By using the plane reflector 4, the length of the antenna in the axial direction can be shortened.

Next, FIG. 4 shows a multi-beam antenna according to a fourth embodiment of the present invention. This fourth embodiment shows the case of a three-beam antenna. The main reflecting mirror 1 includes three partial reflecting mirrors 31,
The partial reflecting mirrors 31 and 32 are joined along the joining boundary line 2a, and the partial reflecting mirrors 32 and 33 are joined along the joining boundary line 2b.

The partial reflecting mirror 31 is a part of the paraboloid of revolution A,
The partial reflecting mirror 32 is a part of the paraboloid of revolution B, and the partial reflecting mirror 33 is a part of the paraboloid of revolution C. In addition, the paraboloids of revolution A, B, and C have different focal points F1 and Fb, respectively.
, rotation center shafts 41 and 42 facing in a different direction from the FC.
, 43. Since the operating principle is the same as that of the first embodiment, its explanation will be omitted.

As can be seen from the above description, the present invention can be similarly applied to cases of four or more bits.

In the above explanation, the case where the multiple focal points and the rotation center axes of the multiple paraboloids of revolution are on the same plane is explained, but this is not necessarily the case. The rotation center shafts 41 and 42 may be in a twisted relationship with each other.

That is, the central axes 41 and 42 may extend in any direction other than within the same plane, and the angles formed by each central axis and each primary radiator do not need to be equal.

Furthermore, the focal lengths of the respective paraboloids of revolution do not have to be equal, and the outer peripheral shape of the main reflecting mirror may also be arbitrary.

(Effects of the Invention) As explained above, according to the multi-beam antenna of the present invention, the plurality of irradiation areas of one main reflecting mirror are
Although there is an appropriate overlap between adjacent irradiation areas, the curved surface shape of each irradiation area is a paraboloid of rotation that is approximately equal to the curved surface shape of the irradiation area when one main reflecting mirror and one irradiation area are used. Since it can be an object surface, each irradiation area can be regarded as a mutually independent paraboloid of revolution reflecting mirror. Therefore, according to the present invention, a highly efficient multi-beam antenna can be constructed.

Further, by indirectly transmitting the irradiated radio waves from the plurality of primary radiators to the main reflecting mirror via one plane reflecting mirror, there is an effect that the antenna axis length can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a diagram showing a second embodiment of the present invention, and FIG. 3 is a diagram showing a third embodiment of the present invention (
FIG. 4 is a diagram showing a fourth embodiment (three-beam antenna) of the present invention, and FIG. 5 is a diagram showing a conventional multi-beam antenna. 1... Main reflecting mirror, 2.2a, 2b...
・Joining boundary line, 4...Flat reflector, 5...
..... Rotating paraboloid reflector, 6..... Power supply section,
7...Low noise amplifier, 21.22.23...
...Primary radiator, 41... Paraboloid of revolution A
42... Center axis of rotation of paraboloid of revolution B, 43... Center axis of rotation of paraboloid of revolution C, 50... Central axis of antenna, (stomach)··
...Overlapping part, A'', B''...Irradiation area, agent Yoshihiro Yawata (patent attorney)
l Zumoto Kari/) 2nd Cicada version with a strong friend Marnaby A antenna 2 Figure (b) Honto 443 poor service @) Kohoro Deketo - ^ Antenna No. 3
Figure (b) The 4th round beam antenna related to the 4th poor example of Honmitsu Tomo
Figure Δθ ~ A row of the round beam Y″7 tenna of the east side Figure 5

Claims (1)

[Claims] A plurality of partial reflecting mirrors each consisting of a part of a plurality of paraboloids of revolution having different focal positions are joined together with the central axes of rotation of the plurality of paraboloids of revolution oriented in different directions. one main reflecting mirror consisting of one main reflecting mirror; and to emit radio waves directly to the main reflecting mirror so that the corresponding partial reflecting mirror of the main reflecting mirror and a part of the partial reflecting mirror adjacent thereto serve as an irradiation area. A planar reflector plate disposed at each of the plurality of focal positions or interposed between the main reflecting mirror and the plurality of focal positions to indirectly radiate radio waves to the main reflecting mirror. A multi-beam antenna comprising: a plurality of primary radiators arranged at each of a plurality of mirror image point positions symmetrical to each of the plurality of focal positions with respect to a plane reflector.