JP2596611B2 - Antenna device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device capable of beam scanning over a wide range.

[Conventional technology]

A conventional antenna device will be described. FIG. 6 is a view showing the XZ plane of the conventional antenna apparatus, FIG. 7 is a view showing the YZ plane, and FIG. 8 is a view showing the operation of the conventional antenna apparatus. ) Is a reflecting mirror, (2) is a primary radiator, (3) is a focal point of a parabola constituting the reflecting mirror (1),
(4) is the main axis of the parabola, (5) is on the same plane as the parabola, and is a rotation axis orthogonal to the main axis, and (6) is to rotate the focal point (3) around the rotation axis (5). The resulting arc or focal line, (7) is the beam direction radiated from the primary radiator (2), and (13) is a footprint formed on a plane by the beam radiated from the primary radiator.

Next, the operation will be described. As an antenna device that performs a wide beam scanning using a reflector-type antenna, a part of a parabola is coplanar with the parabola and rotates around a rotation axis (5) orthogonal to the main axis (4) of the parabola. There is an antenna device using a part of a curved surface obtained as a reflection mirror (1). In the antenna device, the focal point (3) of each parabolic component of the mirror surface (1) forms an arc obtained by rotating the focal point (3) around the rotation axis (5), that is, a focal line (6). . When electromagnetic waves are individually radiated from the primary radiators (2a ₁ ) to (2a _n ) arranged on the focal line (6), the reflecting mirror (1) is rotationally symmetric with respect to the rotation axis (5). Therefore, the electromagnetic wave beam due to the emitted electromagnetic wave
In the figure YZ plane, the beam directions (7a ₁ ) to (7
a _n ). The beam direction (7) in the XZ plane in FIG. 6 coincides with the main axis (4) direction. Therefore, the eighth
Electromagnetic beam emitted to the beam direction as shown in FIG. _{(7a 1) ~ (7a n} ) forms a Futsuto print linearly arranged on a plane _{(13a 1) ~ (13a n} ).

[Problems to be solved by the invention]

Since the conventional antenna device is configured as described above, the conical beam scanning, that is, the beam direction (7a) to
In order to perform beam scanning in which (7c) is a conical body whose rotational axis (5) is a rotationally symmetric axis, the primary radiator (2) must be arranged so as to be deviated from the focal line (6). However, the primary radiator (2) has a problem in that the deviation from the focal line (6) degrades the performance of gain fluctuation and beam width fluctuation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and does not deviate from the focal line (6) of the primary radiator (2), and therefore, varies the gain and beam width during scanning. It is an object of the present invention to obtain an antenna device that can perform conical beam scanning without deteriorating the performance of the antenna.

[Means for solving the problem]

The antenna device according to the present invention is the antenna device according to the above-mentioned antenna device, wherein a reflecting mirror is formed as a part of a curved surface obtained by rotating a part of a parabola around a rotation axis on the same plane as the parabola, and the rotation axis and the parabola are formed. The angle formed by the main axis is a value other than 90 °.

[Action]

The antenna device according to the present invention has a conical primary radiator arranged on a focal line by setting the angle between the main axis of the parabola constituting the reflector and the rotation axis for rotating the parabola to a value other than 90 °. Achieve beam scanning.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, (1) indicates that a part of the parabola is on the same plane as the parabola, and the main axis of the parabola is
A reflecting mirror consisting of a part of a curved surface obtained by being rotated on an axis of rotation intersecting at an angle other than 90 °, (2) a primary radiator,
(3) is the focus of the parabola, (4) is the main axis of the parabola, (5) is the rotation axis, and (6) is an arc obtained by rotating the focus (3) around the rotation axis (5). Scoring line,
(7) is the beam direction emitted from the primary radiator (2),
(8) is the angle between the main shaft (4) and the rotating shaft (5), (9)
Is a specific point on the parabola constituting the mirror surface (1), (10) is the intersection of the principal axis (4) and the rotation axis (5), and (11) is a projection point projected onto the principal axis (4) from both ends of the parabola. , (12) are the midpoints of the projection points (11a) and (11b). In FIG.
(13) is a footprint formed on a plane by the beam emitted from the primary radiator (2). 4 and 5 are views showing an example of a tournament type beam switching circuit, wherein (14) is a ferrite switch for switching beams, and (15) is a power distributor for distributing power to a desired power distribution ratio. It is.

Next, the operation of the present invention will be described for the case where this antenna device is used as a transmitting antenna. In the antenna device according to the present invention, the reflecting mirror (1) is such that a part of the parabola is on the same plane as the parabola, that is, X-axis shown in FIG.
It consists of a part of a curved surface obtained by being rotated around a rotation axis (5) on the Z plane, and the angle between the main axis (4) of the parabola and the rotation axis (5) is other than 90 °. The inclination angle is (8). As a result, the focus (3) of the parabola is
An arc or focal line obtained by rotating the focal point (3) around the rotation axis (5) is formed.

Primary radiators (2a ₁ ) to (2a) arranged on the focal line (6)
The beam formed by the electromagnetic waves emitted from a _n )
Since the reflecting mirror (1) is rotationally symmetric with respect to the rotation axis (5), the beam direction (7
a ₁ ) to (7a _n ). In the XZ plane, the beam direction (7) coincides with the main axis (4). Therefore the third
As shown in the figure, beam by beam direction (7a ₁₎ ~ (7a _n) scanning a conical beam scanning a rotating shaft (5) and the axis of rotational symmetry. In other words, beam direction (7a ₁ ) to (7a _n )
Are radiated to the footprints (13a ₁ ) to (13a _n ) arranged on an arc on a plane orthogonal to the rotation axis (5).
To form

By the way, in the reflecting mirror (1), the relationship between the reflecting mirror (1) and the rotation axis (5) is required to minimize the mirror aberration when the arc component of the reflecting mirror (1) is viewed from the focal point (3). Is done. To realize this, a specific point (9) on the mirror surface (1)
And the focal point (3) is equal to the distance between the intersection (10) of the main axis (4) and the rotation axis (5) and the focal point (3). Here, the specific point (9a) is the intersection of the bisector of the angle looking at both ends of the parabolic component of the reflecting mirror (1) from the focal point (3) and the parabola. Alternatively, the point on the parabola, which is the midpoint (12) of the projection point (11a) at the upper end and the projection point (11b) at the lower end when the parabolic component is projected on the main axis (4), may be set as the specific point (9b). Alternatively, the specific point (9a) may be an intersection between the beam axis of the primary radiator (2) arranged in the same plane as the parabola and the parabola. In the above embodiment, the primary radiators (2) are arranged on the focal line (6). However, by arranging them in multiple stages near the focal line (6), simultaneous use in multiple frequency bands is possible. As shown in FIG. 4, a beam switching circuit in which a ferrite switch (14) is arranged in a tournament form as a power supply circuit to the primary radiator (2) enables beam scanning with one transmitter. . Further, as shown in FIG. 5, a fixed power divider (1
When 5) is provided, beam shaping by a plurality of primary radiators becomes possible, and a half scanning interval of the beam switching circuit shown in FIG. 4 can be realized. Further, by making the power distributor (15) a variable power distributor, continuous beam scanning becomes possible.

In the above embodiment, the primary radiator (2) does not block the beam of the reflecting mirror (1). Although the offset feed type is used, the reflecting mirror (1) may be a center feed type symmetrical to the main axis (4).

In the above embodiment, the ferrite switch (12) constituting the power transmission circuit is a one-input N such as a PIN diode switch.
An output switch may be used, and an effect similar to that of the above embodiment can be obtained.

Further, in the above-described embodiment, the transmitting antenna has been described. However, the receiving antenna may be used, and the same effects as in the above-described embodiment can be obtained.

〔The invention's effect〕

As described above, according to the present invention, the angle between the main axis of the parabola constituting the reflecting mirror and the rotation axis for rotating the parabola is determined.
Since it is configured to have a value other than 90 °, conical beam scanning can be realized by the primary radiators arranged on or near the focal line, so gain fluctuations due to displacement of the primary radiator arrangement position from the focal point during beam scanning In addition, there is an effect that performance deterioration such as beam width fluctuation does not occur.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an antenna device according to an embodiment of the present invention.
FIG. 2 shows the Z plane, and FIG.
FIG. 3 is a diagram showing a Z plane, FIG. 3 is a diagram showing an operation example of the present invention, FIG. 4 is a diagram showing one embodiment of a power supply circuit, FIG. The figure shows the XZ plane of the conventional antenna device, and FIG. 7 shows the Y-plane of the conventional antenna device.
FIG. 8 is a diagram showing the Z plane, and FIG. 8 is a diagram showing the operation of the conventional antenna device. In the figure, (1) is a reflecting mirror, (2) is a primary radiator, (3) is a focal point, (4) is a main axis, (5) is a rotation axis, (6) is a focal line,
(7) is the beam direction, (8) is the tilt angle, (9) is the specific point, (10) is the intersection, (11) is the projection point, (12) is the midpoint,
(13) is a footprint, (14) is a ferrite switch, and (15) is a power distributor. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continued on front page (72) Inventor Hiroaki Nakahan 325 Kamimachiya, Kamakura-shi, Kanagawa Prefecture Mitsubishi Electric Corporation Kamakura Works (72) Inventor Tatsuhiro Noguchi 325 Kamimachiya, Kamakura-shi, Kanagawa Prefecture Mitsubishi Electric Kamakura Corporation Inside the factory (72) Inventor Soji Kobayashi 325 Kamimachiya, Kamakura City, Kanagawa Prefecture Mitsubishi Electric Corporation Kamakura Works (72) Inventor Takashi Katagi 325 Kamimachiya, Kamakura City, Kanagawa Prefecture Mitsubishi Electric Corporation Kamakura Works (72) Inventor Takashi Hirushii 5-1-1, Ofuna, Kamakura City, Kanagawa Prefecture Inside the Information and Electronics Research Laboratories, Mitsubishi Electric Corporation (72) Inventor Norio Miyahara 5-1-1, Ofuna, Kamakura City, Kanagawa Prefecture Mitsubishi Electric Co., Ltd. (56) References JP-A-46-7776 (JP, A)

Claims (4)

(57) [Claims] 1. A part of a curved surface obtained by rotating a part of a parabola around a straight line on the same plane as the parabola, and forming an angle between a principal axis of the parabola and the straight line by 90 degrees.
A reflecting mirror set to a value other than °, a primary radiator comprising element antennas arranged on or near a curve (focal line) obtained by rotating the focus of the parabola around a straight line, and An antenna device comprising a feeder circuit connected to a primary radiator, wherein the feeder circuit comprises a tournament-type beam switching circuit including a ferrite switch, and a power distributor connected to the beam switching circuit. Antenna device. 2. A part of a curved surface obtained by rotating a part of a parabola around a straight line on the same plane as the parabola, and forming an angle between the principal axis of the parabola and the straight line by 90 degrees.
A reflecting mirror set to a value other than °, a primary radiator comprising element antennas arranged on or near a curve (focal line) obtained by rotating the focus of the parabola around a straight line, and In an antenna device including a feeder circuit connected to a primary radiator, the distance between a specific point on the parabola and the focal point of the parabola is equal to the distance between the intersection of the main axis of the parabola and the straight line and the focal point of the parabola. An antenna device, wherein the specific point is an intersection between the beam axis of a primary radiator and the parabola arranged in the same plane as the parabola. 3. A part of a curved surface obtained by rotating a part of a parabola around a straight line lying on the same plane as the parabola, and forming an angle between the principal axis of the parabola and the straight line by 90 degrees.
A reflecting mirror set to a value other than °, a primary radiator comprising element antennas arranged on or near a curve (focal line) obtained by rotating the focus of the parabola around a straight line, and In an antenna device including a feeder circuit connected to a primary radiator, the distance between a specific point on the parabola and the focal point of the parabola is equal to the distance between the intersection of the main axis of the parabola and the straight line and the focal point of the parabola. An antenna device, wherein the specific point is an intersection of a bisector of an angle looking into both ends of the parabola from a focal line and the parabola. 4. A part of a curved surface obtained by rotating a part of a parabola around a straight line on the same plane as the parabola, and forming an angle between the principal axis of the parabola and the straight line by 90 degrees.
A reflecting mirror set to a value other than °, a primary radiator comprising element antennas arranged on or near a curve (focal line) obtained by rotating the focus of the parabola around a straight line, and In an antenna device including a feeder circuit connected to a primary radiator, the distance between a specific point on the parabola and the focal point of the parabola is equal to the distance between the intersection of the main axis of the parabola and the straight line and the focal point of the parabola. An antenna apparatus, wherein the specific point is a point on the parabola that is a midpoint between an upper end and a lower end when the specific point is projected on a main axis of the parabola.