JPH1127036A - Antenna device - Google Patents

Abstract

(57) [Problem] To provide an antenna device capable of forming a substantially constant beam pattern regardless of a beam scanning direction. SOLUTION: Between a primary radiator 5 and a secondary radiator 2,
A reflector 3 for reflecting a radar beam or the like emitted from the primary radiator 5 is provided rotatably. The reflection plate 3 is made of a member whose shape can be changed. The shape of the reflector 3 is changed according to the rotation position (beam scanning angle) of the reflector 3. The side portion of the reflection plate 3 may be formed to be movable, and the angle of the side portion may be changed. The curvature of the reflector 3 may be changed by changing the distance between the left and right ends and the distance between the upper and lower ends of the reflector 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical scanning type antenna device for mechanically performing beam scanning.

[0002]

2. Description of the Related Art As a mechanical scanning type radar device (antenna device), there are known a device for rotating the radar device itself and a device for rotating a primary radiator and subsequent components using a rotary joint or the like. Also, US Pat. No. 5,579,021,
A combination of a mechanical scanning antenna device and a parallel radiator is described.

[0003]

However, an antenna device having a structure in which the primary radiator and the subsequent radiator are rotated needs to rotationally drive a relatively heavy antenna such as a reflector antenna, a parabolic antenna, and a lens antenna. For this reason, the driving motor becomes large, and it is difficult to secure reliability for a long period of time.

The inventor of the present invention arranges the reflector 13 at a position offset from the focal point of the lens antenna 2 which is a secondary radiator, and rotates or swings the reflector 13 to obtain a high-frequency beam ( The antenna device 11 of FIG. 8 in which the radar beam is scanned is devised.
Various tests were performed. In FIG. 8, reference numeral 4 denotes, for example, a transmitter / receiver for high-frequency signals in the millimeter wave band, reference numeral 5 denotes a primary radiator, and reference numeral 6 denotes a rotating mechanism provided with a motor or the like for rotating or swinging the reflecting plate 13. is there. The reflecting surface of the reflecting plate 13 is always a plane.

Generally, a lens antenna is designed on the assumption that a beam source is used at the focal point of the lens antenna. Therefore, the antenna device 1 shown in FIG.
In No. 1, it was found that the beam pattern was different depending on the beam scanning angle.

FIG. 7 is an explanatory diagram showing the relationship between the scanning angle and the sharpness (degree of sharpness or broadness) of the beam pattern in the antenna device 11 of FIG.
As shown in FIG. 7, when the reflecting plate 13 having a flat reflecting surface is swung, the sharpness of the beam pattern changes depending on the scanning angle. In the radar apparatus, if the sharpness of the beam pattern changes, the maximum detection distance is shortened and the azimuth resolution is undesirably reduced. It is conceivable that the lens shape of the lens antenna 2 is a complicated shape that can obtain a constant beam pattern regardless of the beam scanning angle, but a lens antenna having a complicated lens shape is not mass-produced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an antenna device capable of forming a substantially constant beam pattern regardless of a scanning angle.

[0008]

An antenna device according to the present invention is an antenna device for scanning a beam by reflecting a beam radiated from a primary radiator by a movable reflecting portion, and the antenna device includes a reflecting portion. And a deforming means for changing the shape of the reflecting portion in accordance with the movable position of the light source.

An antenna device according to the present invention includes a primary radiator for transmitting or receiving a beam, a reflector for reflecting a beam radiated from the primary radiator, and a rotating mechanism for rotating and driving the reflector. And a secondary radiator for converging the beam reflected by the reflector, wherein the reflector is made of a member whose shape can be changed.

An antenna device according to the present invention includes a primary radiator for transmitting or receiving a beam, a reflector for reflecting a beam radiated from the primary radiator, and a rotating mechanism for rotating and driving the reflector. , Wherein the reflector is made of a member whose shape can be changed, and the antenna device is provided with deformation means for changing the shape of the reflector in synchronization with the rotation of the reflector. I do.

An antenna device according to the present invention includes a primary radiator for transmitting or receiving a beam, a reflector for reflecting a beam emitted from the primary radiator, and a rotating mechanism for rotating and driving the reflector. A secondary radiator that converges the beam reflected by the reflector, wherein the reflector is made of a member whose shape can be changed, and the antenna device is synchronized with the rotation of the reflector. The secondary radiator is provided with a deformation means for changing the shape of the reflector, and the secondary radiator comprises a lens or a parabolic antenna.

In the antenna device according to the present invention, the reflector (reflector) for reflecting the beam radiated from the primary radiator
By changing the shape of the beam according to its rotational position (scanning direction), it is possible to control the beam pattern of the beam reflected by the reflecting plate (reflecting portion), and to maintain a substantially constant beam pattern regardless of the scanning direction. It becomes possible.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing the structure of the antenna device according to the present invention.

The antenna device 1 includes a lens antenna 2 as a secondary radiator, a reflector 3 as a reflector, a transmitter / receiver 4, a primary radiator 5, a rotating mechanism 6, and a deformation means (not shown). 7 is provided. The reflecting plate 3 is a lens antenna 2
Is located at a position offset from the focal point. The rotation mechanism 6 is configured using a motor, a speed reduction mechanism, and the like.
The primary radiator 5 emits a beam based on a transmission signal supplied from the transceiver 4. The primary radiator 5 receives the signal reflected by the target and supplies the signal to the transceiver 4. Note that a parabolic antenna or a radiation plate may be used as the secondary radiator.

FIGS. 2 to 4 are explanatory views showing examples of changes in the shape of the reflector. The reflecting plate 3 has a structure in which the shape of the reflecting surface can be changed. FIG. 2 shows a configuration in which opening and closing plate portions (movable plate portions) 3b and 3c are openably and closably connected to both sides of a central plate portion 3a of the reflection plate 3. FIG. 3 shows that the curvature of the reflector 3 can be changed by changing the distance between both ends of the reflector 3. FIG. 4 shows that the curvature of the reflection plate 3 can be changed by changing the distance in the left-right direction and the vertical direction of the reflection plate 3. 3 or 4, the holding force may be adjusted by a deforming means (not shown) for holding the reflector 3.

FIG. 5 is an explanatory view showing one structural example of a deforming means for the reflecting plate of FIG. The deformation means 7 includes an arm member 7 fixed to the rotation shaft 6a of the rotation mechanism 6 shown in FIG.
1, stepping motors 72R and 72L fixed to the left and right ends of the arm member 71, respectively, and a cam 73 driven by the stepping motors 72R and 72L.
R, 73L and the respective open / close plate portions 3b, 3c are connected to cams 73R, 7R.
Return springs 74R and 74L for pulling to the 3L side.

The opening / closing plate portions (movable plate portions) 3b and 3c are connected to the central plate portion 3a via hinges (not shown) so as to be openable and closable. Note that the arm member 71 may be fixed to the central plate portion 3a of the reflection plate 3. The deformation control means (not shown) drives each of the stepping motors 72R and 72L so that the opening / closing amount of the opening / closing plate portion is set in advance corresponding to the turning position (or the beam scanning angle) of the reflecting plate 3.
Thus, the opening / closing plates 3b and 3c are driven to open and close by the cams 73R and 73L, and the shape of the reflecting plate 3 is changed.

In the structure in which the reflecting plate 3 is swung over a predetermined angle range, the driving power of each of the stepping motors 72R and 73L can be supplied by a flexible cable. When the reflecting plate 3 is rotated 360 degrees, a slip ring or the like is provided on the rotating shaft 6a of the rotating mechanism 6 to supply driving power to each of the stepping motors 72R and 73L. Alternatively, a battery and a wireless receiver may be provided on the reflector 3 side, and a stepping motor drive command signal may be supplied by wireless communication to control the operation of the stepping motors 72R and 73L. Central plate 3a of reflector 3
The reflection surface may not be arranged in parallel with the axial direction of the rotating shaft 6a.

The power for deforming the reflector 3 is not only the power of the motor but also, for example, a liquid is sealed in the reflector and the shape of the reflector 3 is three-dimensionally changed by utilizing the pressure of the fluid. Alternatively, the shape of the reflecting plate 3 may be changed by gravity using the weight of the fluid. Further, the reflector 3 may be rotated around its central axis, and the shape of the reflector 3 may be changed by its own centrifugal force, or the change in shape may be controlled by the rotation speed. Further, the shape of the reflection plate 3 may be changed using a shape memory alloy.

FIG. 6 is an explanatory diagram showing the relationship between the scanning angle and the sharpness (degree of sharpness or broadness) of the beam pattern in the antenna device according to the present invention. By changing the shape of the reflecting plate 3 according to the scanning angle, it is possible to keep the sharpness (sharpness) of the beam pattern almost constant as shown in FIG. On the other hand, in the case of the reflecting plate 13 having a flat reflecting surface, the beam pattern changes depending on the scanning angle as shown in FIG.
Along with this, the sharpness (sharpness) of the beam pattern changes. In FIGS. 6 and 7, the scanning angle on the horizontal axis is 0 degree at the center of the beam scanning range.

When the antenna device 1 according to the present invention is applied to an on-vehicle radar device, a scanning angle of 0 degree is set as a traveling direction of a vehicle, and a scanning range is set so that a roadside object (a target in a roadside zone) can be searched. In addition to the setting, the shape of the reflector 3 may be changed so that the beam pattern becomes broad at a scanning angle for searching for a roadside object. At a scanning angle for searching for a roadside object, by setting the beam pattern to be broad, a short range can be set as a search range and the search range can be widened. Therefore, a short range can be detected at a wide angle. Even if the swing range of the reflector 3 is constant, it is possible to search a wider range than the swing range of the reflector 3 by making the beam pattern broad at both ends of the swing range.

[0022]

As described above, according to the antenna device of the present invention, it is possible to form a substantially constant beam pattern regardless of the scanning angle (scanning direction). Further, it becomes possible to sharpen or broaden the beam pattern for a specific scanning angle.

[Brief description of the drawings]

FIG. 1 is a simplified perspective view showing the structure of an antenna device according to the present invention.

FIG. 2 is a simplified explanatory view showing an example of a change in the shape of the reflector of FIG. 1;

FIG. 3 is a simplified explanatory diagram showing another example of a change in the shape of the reflector in FIG. 1;

FIG. 4 is a simplified explanatory view showing still another example of a shape change of the reflection plate of FIG. 1;

FIG. 5 is a simplified explanatory view showing one structural example of a deforming means.

FIG. 6 is a simplified explanatory diagram showing the relationship between the scanning angle and the sharpness (degree of sharpness or broadness) of a beam pattern in the antenna device of the present invention.

FIG. 7 is a simplified explanatory diagram showing the relationship between the scanning angle and the sharpness (degree of sharpness or broadness) of a beam pattern in an antenna device to be compared with the present invention.

FIG. 8 is a simplified perspective view showing the structure of an antenna device to be compared with the present invention.

[Explanation of symbols]

Reference numerals 1, 11: antenna device, 2: lens antenna as secondary radiator, 3, 13: reflector plate as a reflection part, 4: transceiver, 5: primary radiator, 6: rotating mechanism, 7: deforming means .

Claims (4)

[Claims] 1. An antenna device for scanning a beam by reflecting a beam emitted from a primary radiator by a movable reflector, wherein the antenna device changes the shape of the reflector according to the movable position of the reflector. An antenna device comprising a deforming means for causing the antenna device to deform. 2. A primary radiator for transmitting or receiving a beam, a reflector for reflecting a beam emitted from the primary radiator, a rotating mechanism for rotating the reflector, and a reflector reflected by the reflector. A secondary radiator for converging the beam,
An antenna device comprising: a reflector that is made of a member whose shape can be changed. 3. An antenna device comprising: a primary radiator for transmitting or receiving a beam; a reflector for reflecting a beam emitted from the primary radiator; and a rotating mechanism for rotating and driving the reflector. An antenna device, characterized in that the reflector is made of a member whose shape can be changed, and the antenna device is provided with deformation means for changing the shape of the reflector in synchronization with the rotation of the reflector. 4. A primary radiator for transmitting or receiving a beam, a reflector for reflecting a beam radiated from the primary radiator, a rotating mechanism for rotating the reflector, and a light reflected by the reflector. A secondary radiator for converging the beam,
A reflector comprising a member whose shape can be changed, the antenna device comprising a deforming means for changing the shape of the reflector in synchronization with the rotation of the reflector, and a secondary radiator. An antenna device comprising a lens or a parabolic antenna.