JP3413865B2 - Multi-beam antenna - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-beam antenna which forms a plurality of beams by arranging a plurality of primary radiators on one reflecting mirror.

[0002]

6 and 7 are views showing a conventional multi-beam antenna, in which 1 is a reflecting mirror, 2 is a primary radiator, 3 is a beam axis formed by the reflecting mirror, and 4 is a primary radiator. Is a beam axis formed by, and 5 is a rotation axis of the reflecting mirror, and 6 is an arc formed by a focus of a parabola.

Next, the operation will be described. As a multi-beam antenna in which a plurality of beams are arranged in a wide range by using a reflector antenna fixed, a part of a curved surface obtained by rotating around a parabola with a straight line on the same plane as the parabola as a rotation axis 5 There is a multi-beam antenna that constitutes the reflecting mirror 1. In the above multi-beam antenna,
A primary radiator 2a arranged on an arc 6 obtained by rotating the focal point of a parabola forming the reflecting mirror 1 around a rotation axis 5.
The electromagnetic waves radiated in the directions in which the maximum electric field radiated from ˜2c, that is, the beam axes 4a to 4c, are reflected.
And forms beams in the directions of beam axes 3a to 3c connecting the points where the primary radiators 2a to 2c are arranged and the center of the arc 6. Here, since the reflecting mirror 1 is a rotationally symmetric body with respect to the rotation axis 5, it is possible to obtain a uniform radiation characteristic of each beam formed regardless of the scanning angle of the beam axes 3a to 3c. . Therefore, when the beam axes 4a to 4c of the primary radiators 2a to 2c are tilted from the plane including the normal line of the arc 6 at the point where the primary radiators are arranged, the beam axes 3a to 3c from the reflecting mirror 1 are It deviates from the desired direction.

In the conventional multi-beam antenna, the beam axes 4a to 4c of the primary radiators 2a to 2c coincide with the offset angle of the parabola within the plane including the rotation axis 5, and the rotation axis 5a.
It is set so as to coincide with the normal direction of the arc 6 in the plane perpendicular to. Further, the outer circumference of the reflecting mirror 1, that is, the aperture diameter, is such that the beams 3a to 3c form a desired beam width in a plane including the rotation axis 5, so that the maximum scanning angle of the beam, that is, the primary The amount of leakage of the electromagnetic waves emitted from the radiators 2a and 2c without hitting the mirror surface is set to a desired value.

[0005]

Since the conventional multi-beam antenna is constructed as described above, it is reflected when the beam axis of the primary radiator is tilted from the plane including the focal point and the rotation axis where the primary radiator is arranged. Since the mirror is formed of an arc, the beam axis direction formed by the reflecting mirror does not face a desired direction, which causes a problem that the beam scanning characteristic is deteriorated.

Further, since the conventional multi-beam antenna is constructed as described above, there is a problem that the aperture diameter of the reflecting mirror increases as the beam scanning angle increases.

The present invention has been made in order to solve the above problems, and the reflecting mirror is provided even when the beam axis of the primary radiator is inclined with respect to the plane including the focal point and the rotation axis in which the primary radiator is arranged. To obtain a multi-beam antenna capable of improving the beam scanning characteristics by directing the beam axis direction formed by the laser beam to a desired direction and suppressing the increase in the aperture diameter of the reflecting mirror due to the increase in the beam scanning angle. With the goal.

[0008]

A multi-beam antenna device according to a first embodiment of the present invention is a primary radiator from a point where any one primary radiator is arranged on an arc formed by a focal point of a reflecting mirror. The length of the line segment projected into the plane including the above-mentioned arc of the line segment connecting the point where the beam axis of the above-mentioned intersects the reflecting mirror is made equal to the radius of the above-mentioned arc.

In the multi-beam antenna of the second embodiment according to the present invention, the arc of a line connecting the point where the primary radiators are arranged on the arc and the point where the beam axis of the primary radiator intersects with the reflecting mirror. It is configured such that the average value of the lengths of the line segments projected in the plane including is equal to the radius of the arc.

Further, in the multi-beam antennas of the third and fourth embodiments according to the present invention, the beam axes of the primary radiators intersect at one point on the reflecting mirror, and the difference in the distance from each primary radiator to the reflecting mirror. It is configured to suppress the minimum.

The multi-beam antenna according to the fifth embodiment of the present invention is constructed so that the beam axes of the primary radiators intersect at one point on the reflecting mirror, and the reflecting mirror is formed by any one primary radiator. The outer circumference of the reflecting mirror when viewed from the beam axis is configured to be a circular arc.

[0012]

In the multi-beam antenna device of the first embodiment, a line connecting the point where any one of the primary radiators on the arc formed by the focal points is arranged and the point where the beam axis of the primary radiator intersects with the reflecting mirror. The length of a line segment projected in a plane including the above-mentioned arc is equal to the radius of the above-mentioned arc, so that the beam axis of the primary radiator with respect to one beam to be formed is set to the aligned focus of the primary radiator. When tilted with respect to the plane including the rotation axis, the beam axis direction can be directed to a desired direction.

Further, in the multi-beam antenna of the second embodiment, a line segment connecting the points where the primary radiators are arranged on the above-mentioned arc to the point where the beam axis of the primary radiator intersects the reflecting mirror is in a plane including the above-mentioned arc. By making the average value of the projected line segment lengths for each primary radiator equal to the radius of the arc,
It is possible to minimize the deviation of the beam axis from the desired direction when the beam axis of the primary radiator is tilted with respect to the plane including the arrayed focal point and rotation axis of the primary radiator for all the formed beams. it can.

In the multi-beam antennas of Examples 3 and 4, the beam axes of the primary radiators intersect at one point on the reflecting mirror, so that the aperture diameter of the reflecting mirror increases as the scanning angle increases. Was unnecessary.

Further, the multi-beam antenna of the fifth embodiment is constructed such that the beam axes of the primary radiators intersect at one point on the reflecting mirror, and the beam axis formed by the reflecting mirrors by any one primary radiator is The aperture diameter of the antenna was set to the minimum by constructing the outer circumference of the reflecting mirror that was seen as an arc.

[0016]

EXAMPLES Example 1. 1 and 2 are schematic configuration diagrams showing Embodiment 1 of the present invention, FIG. 3 is a diagram showing geometrical optical characteristics of an electromagnetic field, 1 is a reflecting mirror, 2 is a primary radiator, and 3 is a reflecting mirror. Formed by the primary radiator, 4 is the beam axis formed by the primary radiator, 5 is the axis of rotation of the reflecting mirror, 6 is an arc formed by the focus of a parabola, and 7 is the reflection in the plane including the arc 6. The projection of the mirror beam axis 3 and 8 is the projection of the primary radiator beam axis 4 into the plane containing the arc 6.

Next, the operation will be described. In the figure, a multi-beam antenna constitutes a reflecting mirror 1 from a part of a curved surface obtained by rotating a parabola around a straight line on the same plane as the parabola about a rotation axis 5, and the focal point of the parabola forming the reflecting mirror 1 is formed. The primary radiators 2a to 2c are arranged on an arc 6 obtained by rotating around the rotation axis 5. In the multi-beam antenna, the electromagnetic waves emitted from the primary radiators 2a to 2c in the beam axes 4a to 4c are collected by the reflecting mirror 1 to form beams in the beam axes 3a to 3c. The beams 3a to 3c formed by the reflecting mirror are determined by the parabola forming the reflecting mirror 1 in the plane including the rotation axis 5. Further, the beam axes 4a to 4c of the primary radiators 2a to 2c include the point where the primary radiators 2a to 2c are arranged and the rotational axis 5, although they are determined by an arc forming a mirror surface in a plane perpendicular to the rotational axis 5. When tilted from the plane, the beam axes 3a to 3c do not face the desired direction. Here, a line segment of a projection 8 on a plane including the above-mentioned arc, which is a line segment connecting a point on the arc 6 where the primary radiator 2a is arranged and a point where the beam axis 4a of the primary radiator 2a intersects the reflecting mirror. By making the length equal to the radius R of the arc 6, as shown in FIG. 3, the geometrical optical reflection mirror by the projection 7 of the beam axis 3a onto the plane perpendicular to the rotation axis 5 is arranged in the primary radiator 2a. It becomes parallel to the normal to the arc 7. Therefore, the beam axis 3a formed by the reflecting mirror forms a beam in a desired direction even on a plane perpendicular to the rotation axis 5.

Example 2. In the first embodiment, the primary radiator 2
The multi-beam antenna that forms a desired beam with respect to a has been described, but from the point on the arc 6 where the primary radiators 2a to 2c are arranged, the beam axes 4a to 4c of the primary radiators 2a to 2c serve as reflectors. Each primary radiator 2a having a length of a line segment projected into a plane including the above-mentioned arc of a line segment connecting the intersecting points
By making the average value L ′ for 2c equal to the radius R of the arc 6, the beam axis 3a can be obtained in the same manner as in the first embodiment.
Similar effects can be obtained for beams in the ~ 3c direction, and the beam scanning characteristics can be improved for all beams formed by the reflecting mirror 1.

Example 3. 1 and 2 are schematic configuration diagrams showing a third embodiment of the present invention, in which 1 is a reflecting mirror, 2 is a primary radiator, 3 is a beam axis formed by the reflecting mirror, and 4 is a beam formed by the primary radiator. Axis 5 is a rotation axis of the reflecting mirror, 6 is an arc formed by the focus of a parabola, and 9 is a point on the reflecting mirror 1.

Next, the operation will be described. In the figure, a multi-beam antenna constitutes a reflecting mirror 1 from a part of a curved surface obtained by rotating a parabola around a straight line on the same plane as the parabola about a rotation axis 5, and the focal point of the parabola forming the reflecting mirror 1 is formed. The primary radiators 2a to 2c are arranged on an arc 6 obtained by rotating around the rotation axis 5. Here, the beam axes 4a to 4c of the primary radiators 2a to 2c are set to a point 9 on the reflecting mirror 1.
When it is set so as to intersect with the reflecting mirror 1, the outer circumference of the reflecting mirror 1, that is, the aperture diameter can be set so that the beam axes 3a to 3c form a desired beam width. Therefore, the beam axis 3a-
Since it does not depend on the scanning angle of 3c, the aperture diameter does not increase with increasing scanning angle, and point 9 is the primary radiator at the maximum scanning angle of the beam, namely primary radiators 2a and 2c.
By making the distances from the arranged points to the point 9 equal, the difference in the distance from the primary radiators 2a to 2c to the point 9 on the reflecting mirror 1 is minimized and the radiation characteristic of the beam formed by the reflecting mirror 1 is reduced. The difference can be suppressed. Further, the outer circumference of the reflecting mirror 1 is circular when viewed from the beam direction of any one of the beams, so that the efficiency is maximized and the aperture diameter can be minimized.

[0021]

Since the present invention is configured as described above, there is an effect that the beam axis of one beam to be formed can be directed in a desired direction and the beam scanning characteristic can be improved.

Further, there is an effect that it is possible to reduce the deviation of the beam axis due to the fact that the reflecting mirrors are formed by arcs for all the beams to be formed and to improve the beam scanning characteristics.

Further, there is no need to increase the aperture diameter of the reflecting mirror as the scanning angle increases, and the reflecting mirror can be miniaturized.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram in a plane including a rotation axis showing a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram in a plane perpendicular to the rotation axis showing the first embodiment of the present invention.

FIG. 3 is a diagram showing a geometrical optical characteristic of an electromagnetic field according to the present invention.

FIG. 4 is a schematic configuration diagram in a plane including a rotation axis showing a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a third embodiment of the present invention in a plane perpendicular to the rotation axis.

FIG. 6 is a schematic configuration diagram including a rotation axis showing a conventional multi-beam antenna.

FIG. 7 is a schematic configuration diagram showing a conventional multi-beam antenna in a plane perpendicular to the rotation axis.

[Explanation of symbols]

1 reflector 2 Primary radiator 3 Reflector beam axis 4 Primary radiator beam axis 5 rotation axes An arc composed of 6 focal points 7 Reflector Beam Axis Projection 8 Projection of the beam axis of the primary radiator 9 Point on the mirror

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01Q 19/17 H01Q 3/24 H01Q 25/00

Claims (5)

(57) [Claims] 1. A reflecting mirror comprising a part of a curved surface obtained by rotating a parabola around a straight line on a plane including a parabola as a rotation axis, and a focus of the parabola obtained by rotating a focus of the parabola around the rotation axis. In a multi-beam antenna composed of a plurality of primary radiators arranged on an arc of a radius R, the primary radiator is from the point on the arc where one of the plurality of primary radiators is arranged. Of the parabola is determined so that the length L of the line segment obtained by projecting the line segment connecting the intersection point of the beam axis of the mirror and the reflecting mirror into the plane including the arc is equal to the radius R of the arc. Of the above rotation axis
A multi-beam antenna characterized in that a reflecting mirror is constructed by a part of a curved surface rotated around . 2. A reflector comprising a part of a curved surface obtained by rotating a parabola around a straight line on a plane including the parabola as a rotation axis, and a focus of the parabola obtained by rotating the focus of the parabola around the rotation axis. In a multi-beam antenna composed of a plurality of primary radiators arranged on a circular arc having a radius R, the point where the beam axis of the primary radiator intersects the reflecting mirror from the point on the circular arc where the primary radiators are arranged. The rotation axis is determined so that the average L ′ of the plurality of primary radiators of the length L of the line segment obtained by projecting the connecting line segment into the plane including the arc is equal to the radius R of the arc . Parabola above
A multi-beam antenna characterized in that a reflecting mirror is constructed by a part of a curved surface rotated around a rotation axis . 3. A reflecting mirror comprising a part of a curved surface obtained by rotating a parabola having an axis parallel to the beam axis of the reflecting mirror about a straight line on a plane including the parabola as a rotation axis, and a focus of the parabola. at a plurality of multi-beam antenna composed of a primary radiator which is arranged on an arc which is obtained by rotating around the rotary shaft, on said plurality of the primary radiators
A multi-beam antenna characterized in that the beam axes of the respective primary radiators intersect with each other at one point on the reflecting mirror. 4. A reflecting mirror comprising a part of a curved surface obtained by rotating a parabola having an axis parallel to the reflecting mirror beam axis about a straight line on a plane including the parabola as a rotation axis, and a focus of the parabola. In a multi-beam antenna composed of a plurality of primary radiators arranged on an arc obtained by rotating around the rotation axis,
The beam axis of each primary radiator intersects at a point on the reflecting mirror with respect to the direction of the reflecting mirror, and the point on the reflecting mirror is equal to the point where the two most distant ones of the plurality of primary radiators are arranged. A multi-beam antenna characterized in that it is configured to have a distance. 5. The multi-beam according to claim 3 or 4, characterized in that the outer periphery of the reflecting mirror formed by said one of the primary radiators when viewed from the antenna beam axial direction formed by said reflecting mirror is a circular arc. antenna.