JPH09246856A - Horn reflector antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the horn reflector antenna system suitable for an automatic tracking antenna system with a simple structure, a small size, suppressing gain fluctuation in which beam control is made over a wide range. SOLUTION: The system is provided with a primary radiator 5 emitting a circularly polarized wave signal from a circularly polarized wave generator 1, a reflecting mirror 7 converting a wave emitted from the primary radiator 5 into a plane wave and reflected therein, and a vertical direction rotary shaft 9 driving the reflecting mirror 7 in the vertical direction to control a beam deflection angle. Then the combination between the arrangement position of the reflecting mirror 7 and the arrangement position of the vertical direction rotary shaft 9 and the combination between the arrangement position of the vertical direction rotary shaft 9 and the arrangement position of the primary radiator 5 are selected to be the combination of maximizing the gain and the combination minimizing gain fluctuation with respect to the beam deflection angle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horn reflector antenna device suitable as an automatic tracking antenna device.

SUMMARY OF THE INVENTION The present invention relates to a conical horn reflector antenna device having a movable reflecting mirror, which is suitable as an antenna device for automatic tracking. By combining the offset amount of the position of the radiator, it is possible to control the gain fluctuation due to the rotation of the reflecting mirror and to control the beam in a wide range. For example, an image with excellent mobility that does not restrict camera work. Good to use as a transmitting antenna for wireless cameras that can be expected.

[0003]

2. Description of the Related Art A first conventional example of an antenna device used as an automatic tracking antenna is the Institute of Electronics, Information and Communication Engineers, B-II VOL. J76-B-II No. 8 (1
As described on page 674, paragraph 5.3 of 993), there is known a structure in which the opening surface of a conical horn antenna is mechanically controlled to direct it directly in the transmission direction.

In this conventional example, as shown in FIG. 7, a circular polarization generator 101 for converting a linear polarization signal into a circular polarization signal,
Two rotary joints 103 provided to rotate the conical horn horizontally and vertically, respectively.
105, a circular waveguide 107 that propagates a circularly polarized signal,
It is provided with a conical horn antenna section 109 for transmitting the circularly polarized signal propagated through the circular waveguide 107. Further, in order to prevent the deterioration of the circular polarization characteristic by compensating for the phase velocity difference caused by the difference of the polarization plane due to the bending of the circular waveguide 107 for feeding the conical horn antenna section 109, a low loss dielectric is used. A bend compensator (not shown) composed of body screws or the like is provided.

In the above configuration, the circularly polarized wave generator 101 converts the linearly polarized wave signal to be transmitted into right and left circularly polarized wave signals. Then, the converted circularly polarized signal is
It is transmitted from the conical horn antenna section 109 via the two rotary joints 103 and 105 and the circular waveguide 107. In this case, the conical horn antenna unit 109
Mechanical beam control is performed to control the rotary joints 103 and 105 in the horizontal direction and the vertical direction so that the opening surface of the is directly directed to the transmission direction.

[0006] As a second conventional example, B-33 of the proceedings of the IEICE Spring National Convention, 1988,
As described in B-35, a satellite-mounted beam control antenna using a sub-reflector antenna and a satellite communication earth station sub-reflector antenna for satellite tracking are known.

In this second conventional example, as shown in FIG.
Primary radiator 111, sub-reflecting mirror 113, main reflecting mirror 11
5, the radio wave radiated from the primary radiator 111 is reflected from the hyperboloid of the sub-reflecting mirror 113 to the parabolic surface of the main reflecting mirror 115, and in the main reflecting mirror 115, the sub-reflecting mirror 11
The radio wave reflected by 3 is converted into a plane wave and transmitted.

The second conventional example has a much larger structure than the first conventional example. For example, when it is used in a satellite or the like, or when the entire antenna is very large, it is necessary to perform beam control as easily as possible without greatly changing the mechanical size and shape. For this reason, in the second conventional example, the beam can be easily controlled by rotating only the main reflecting mirror 115 or the sub-reflecting mirror 113 without rotating the entire antenna. In actual tracking of geostationary satellites, the position change is small, so beam control is performed in a narrow range.

[0009]

However, the above-mentioned conventional example has the following problems.

That is, according to the first conventional example, since mechanical beam control is performed, the opening surface of the conical horn antenna section 109 is arranged directly in the transmission direction, and the circular waveguide 107 and A bend compensator and rotary joint 105 are required. Therefore, not only the structure becomes complicated, but also a high manufacturing technique is required.

On the other hand, in the second conventional example, while a high gain can be obtained relatively easily and the beam can be controlled easily, the structure is very large and the primary radiator 111 is used.
Since the beam is controlled by fixing the beam and rotating the main reflecting mirror 115 or the sub-reflecting mirror 113, the gain is lowered and the beam control is limited to a narrow range.

As described above, in the first conventional example, the structure of the power feeding system is complicated. Further, the second conventional example has problems that it is very large and the beam control range is narrow, and it is not suitable for an automatic tracking antenna device such as a wireless camera.

The present invention has been made in view of the above circumstances, and an object thereof is a horn suitable as an antenna device for automatic tracking, which is simple and small in size, can suppress a gain variation, and can perform beam control in a wide range. An object is to provide a reflector antenna device.

[0014]

In order to achieve the above object, the invention of claim 1 is a circular polarization generator for converting a linear polarization signal into a circular polarization signal, and this circular polarization generator. A primary radiator that radiates a circularly polarized signal from the antenna, a reflector that converts the radiation wave from this primary radiator into a plane wave and reflects it, and a beam deflection angle by rotating this reflector in the vertical direction. A vertical rotation axis to be controlled is provided, and the combination of the arrangement position of the reflecting mirror and the arrangement position of the vertical rotation axis is set to a combination that maximizes the gain.

According to a second aspect of the present invention, a circularly polarized wave generator that converts a linearly polarized signal into a circularly polarized signal, and a primary radiator that radiates the circularly polarized signal from the circularly polarized wave generator, A reflection mirror for converting the radiation wave from the primary radiator into a plane wave and reflecting it, and a vertical rotation shaft for rotating the reflection mirror in the vertical direction to control the beam deflection angle are provided. The combination of the disposition position and the disposition position of the primary radiator is characterized in that it is set such that the gain variation with respect to the beam deflection angle is minimized.

According to the invention of claim 3, a circular polarization generator for converting a linear polarization signal into a circular polarization signal, and a primary radiator for radiating the circular polarization signal from the circular polarization signal, The reflecting mirror is provided with a reflecting mirror for converting a radiation wave from the primary radiator into a plane wave and reflecting the same, and a vertical rotation axis for rotating the reflecting mirror in a vertical direction to control a beam deflection angle. The combination of the installation position, the installation position of the vertical rotation axis, and the installation position of the primary radiator is set to a combination that maximizes the gain and minimizes the gain fluctuation with respect to the beam deflection angle. It has a feature.

According to the above-mentioned constitutions 1, 2, and 3, it is possible to secure a high gain in a wide range and to perform beam control while suppressing a gain variation.

According to a fourth aspect of the present invention, in the horn reflector antenna apparatus according to the first, second or third aspect, a second circularly polarized wave generator is provided between the circularly polarized wave generator and the primary radiator. It is characterized by interposing.

According to the above arrangement, the circularly polarized wave signal converted by the circularly polarized wave generator can be converted into the linearly polarized wave signal again and radiated.

According to a fifth aspect of the present invention, in the horn reflector antenna apparatus according to the first, second, third or fourth aspect, a horizontal rotating shaft for rotating the reflecting mirror in the horizontal direction is provided.

According to the above arrangement, not only vertical beam control but also horizontal beam control is possible.

[0022]

1 is a block diagram showing an embodiment of a horn reflector antenna device according to the present invention.

As shown in the figure, this antenna device is converted by a circular polarization generator 1 for converting a supplied linear polarization signal into a circular polarization signal, a rotary joint 3, and a circular polarizer 1. A primary radiator 5 that radiates a circularly polarized signal and a reflecting mirror 7 that converts the circularly polarized signal radiated from the primary radiator 5 into a plane wave and reflects the plane wave are provided. The reflecting mirror 7 is rotatably supported around a vertical rotation shaft 9. 11 in the figure
Is the horizontal axis of rotation.

In the above structure, a linearly polarized radio wave is converted into a circularly polarized wave by the circularly polarized wave generator 1. The converted circularly polarized wave is radiated by the primary radiator 5 in the direction of the horizontal rotation axis 11 (Z-axis direction) through the rotary joint 3 which performs beam control in the horizontal direction. The radiated radio wave is reflected by the reflecting mirror 7 and converted into a plane wave. At this time, vertical beam control is performed by rotating the reflecting mirror 7 in the vertical direction.

When this horn reflector antenna device is used as an automatic tracking antenna device, vertical beam control during automatic tracking is achieved by deflecting the beam by rotating the reflecting mirror 7 in the vertical direction.
When the beam is deflected, a decrease in gain cannot be avoided. Therefore,
Offset amount between the position of the reflecting mirror 7 and the position of the vertical rotating shaft 9 (deviation of the vertical rotating shaft 9 from the Z axis and deviation of the reflecting mirror 7 from the Z axis (in FIG. 2, the bisector of the angle AOB and By appropriately combining the angle formed with the Z axis) by calculation, it is possible to reduce the decrease in gain even at the beam deflection angle at which the gain decreases. Further, by appropriately setting the offset amount between the position of the vertical rotation axis 9 of the reflecting mirror 7 and the position of the primary radiator 5 on the y-axis, that is, the deviation of the vertex position of the primary radiator 5 from the origin. It is possible to reduce the gain variation due to the rotation of the reflecting mirror 7.

FIG. 2 shows an analytical model used for calculation. This model is a diagram in which the configuration diagram of FIG. 1 is viewed on the yz plane. Point A to point B of the paraboloid of revolution with the y-axis as the axis of rotation
Up to correspond to the reflecting mirror 7, and the point R corresponds to the vertical rotation axis 9. Further, the aperture diameter of the reflecting mirror 7 is D, the focal length is F,
The focus of the reflecting mirror 7 is O. D _R represents the difference (distance) between the z coordinates of the point R and the point A. The aperture diameter D is determined from the conditions of gain and size, and the focal length F is determined from F / D = 1.0 used in a normal horn reflector antenna.

As shown in FIG. 2, the position of the reflecting mirror 7 is at an angle θa representing the lower end position of the reflecting mirror 7, and the vertical rotation axis 9
Is Ax = D _R / D (when Ax is 0, points A, 1
In this case, the point B is the axis of rotation 9), and the position of the primary radiator 5 can be represented by the y coordinate (yh) of its apex.

Under the above conditions, the directional gain is calculated by the current distribution method using the analytical model. The maximum gain of the beam (gain in the center direction of the beam) can be expressed by Gm (θ, θa, Ax, yh). The angle θ represents the deflection angle of the beam (the positive direction is upward) due to the rotation of the reflecting mirror 7. That is, the gain Gm depends on the beam deflection angle θ and the above-mentioned parameters θa, Ax, yh.
Function.

Next, a case will be described in which the gain Gm is maximized even at a beam deflection angle where the gain Gm decreases. The beam deflection angle θ at which the gain decreases and the coordinate value yh are
Assuming θ = θs and yh = yho (constant), the gain Gm can be expressed as Gm (θs, θa, Ax, yho), and the gain Gm is a function of two parameters θa and Ax, and the gain Gm is The lower end position angle θa of the reflecting mirror 7 (position of the reflecting mirror in claim 1) so that it becomes maximum,
The combination of the position Ax of the rotating shaft 9 (position of the vertical rotating shaft in claim 1) may be obtained.

In FIG. 3, the lower end position angle θa of the reflecting mirror 7 is kept constant, and the position Ax of the rotary shaft 9 is changed from 0 to 1.
The graph shows an image of changes in the gain Gm when the graph is plotted with respect to each lower end position angle θa of the reflecting mirror 7. As shown in the figure, the graph has vertices and θa =
It can be seen that the gain Gm is maximum when θam and Ax = Axm.

FIG. 4A shows a graph image of the gain Gm with respect to the beam deflection angle when the reflecting mirror 7 is rotated in the vertical direction as shown in FIG. As shown in the figure, it can be understood that the gain Gm becomes maximum at the beam deflection angle θ = θs where the gain Gm decreases by changing the lower end position angle θa and the position Ax of the reflecting mirror 7 and combining them optimally.

For example, this horn antenna device is 42G
Consider the case of using as an antenna device for automatic tracking of a Hz high-definition wireless camera. Use frequency 4
1.756 GHz, the primary radiator 5 has an aperture diameter of 36
Using a cone horn having an opening angle of 34 mm and an opening angle of 34 °, the horn axis is aligned with the z axis and the apex is aligned with the point O (yh = 0 mm). The beam control range angle (θ) in this case is from −25 ° to +
The gain Gm (30, θa,
Calculate Ax, 0). Aperture diameter D, focal length F 55m
When the combination of the lower end position angle θa of the reflecting mirror 7 and the position Ax of the rotating shaft 9 is calculated, the optimum value of the lower end position angle θa of the reflecting mirror 7 is 74 °, and the position Ax of the rotating shaft 9 is 0.
46 is obtained.

FIG. 5A shows a gain Gm (θ, 74, 0.46, with respect to the vertical beam deflection angle θ at this time.
The graph which calculated the characteristic of 0) is shown.

Beam deflection angle is downward 25 ° (-25 °)
From 22 to 30 ° upward, the gain is 22 dBi or more, which is a good result. Actually, from the experimental accuracy,
The lower limit position angle θa of the reflecting mirror 7 is about 70 ° to 76 °, and the position Ax of the rotating shaft 9 is about 0.4 to 0.5, which are allowable ranges in design.

As described above, it is understood that the gain can be maximized by combining the arrangement position of the reflecting mirror 7 and the position of the vertical rotation axis 9.

Next, consider the case of controlling the variation of the gain Gm due to the change of the beam deflection angle (θ).

In FIG. 6, θa = θam (constant) and Ax = A
A gain Gm (θ = θam, A when x ′ is constant)
It shows an image of changes in x ', yh). further,
The graph of each position Ax (0 ≦ Ax ≦ 1) of the rotary shaft 9 is calculated by setting Ax = Ax ″ (constant). From the graph, the position Ax of the rotary shaft 9 (vertical in claim 1) The variation of the gain Gm with respect to the beam deflection angle θ is controlled by combining the arrangement position of the rotation axis) and the vertex coordinate value yh of the primary radiator 5 (the arrangement position of the primary radiator in claim 1). I know that I can do it.

In FIG. 5B, Ax = 0.3 and yh =-
6 is a graph showing an example of calculation when it is set to 4.0 mm. This is because the beam deflection angle is -25 ° to +30.
This is an example in which the variation of the gain is suppressed to +1.4 dB in the range up to °. As can be seen from this result, the position Ax of the vertical rotation shaft 9 of the reflecting mirror 7 is determined, and the primary radiator 5 is moved in the y-axis direction, so that the displacement amount or the movement amount of the rotation shaft 9 is changed. It is possible to minimize the variation of the gain Gm.

Further, the gain is maximized and the gain variation is minimized by combining the three positions of the reflecting mirror 7, the vertical rotating shaft 9 and the primary radiator 5. Is possible.

As described above, according to this embodiment, the feeding system does not require a complicated waveguide circuit such as a circular waveguide having a bent portion as in the first conventional example, and the movable portion does not need to be provided. Since only the reflecting mirror 7 is provided, the entire structure is simple and downsized, which is suitable for arranging in a limited space.

It should be noted that another circular polarization generator (second circular polarization generator) may be inserted between the rotary joint 3 and the primary radiator 5. With this configuration, it can be used as a linearly polarized radiation antenna.

Even when the rotary joint 3 is not used, the beam control in one horizontal direction is possible by rotating only the reflecting mirror 7 about the Z axis in the horizontal direction.

[0043]

As described above, according to the first, second and third aspects of the present invention, the combination of the arrangement position of the reflecting mirror and the arrangement position of the vertical rotation shaft, and the arrangement position of the vertical rotation shaft are set. The combination with the disposition position of the primary radiator is set to a combination that maximizes the gain and a combination that minimizes the gain fluctuation with respect to the beam deflection angle, so that a high gain can be secured in a wide range and the gain fluctuation can be secured. It is possible to control the beam while suppressing this. Moreover, since the structure is simple and can be downsized,
A horn reflector antenna device suitable for an automatic tracking antenna device such as a wireless camera can be applied.

According to the invention of claim 4, since the second circularly polarized wave generator is interposed between the circularly polarized wave generator and the primary radiator, it is converted by the circularly polarized wave generator. The circularly polarized signal can be converted back to a linearly polarized signal and radiated.

According to the fifth aspect of the present invention, since the horizontal axis of rotation for rotating the reflecting mirror in the horizontal direction is provided, not only the beam control in the vertical direction but also the beam control in the horizontal direction can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a horn reflector antenna device according to the present invention.

FIG. 2 is an explanatory diagram showing an analysis model used for calculation of the horn reflector antenna device in the embodiment of FIG.

FIG. 3 is an image diagram of a gain Gm of the horn reflector antenna device in the embodiment of FIG.

4 is an image diagram of a gain Gm of the horn reflector antenna device in the embodiment of FIG.

FIG. 5 is an explanatory diagram showing a change in gain Gm with respect to a beam deflection angle θ.

6 is an image diagram of a gain Gm of the horn reflector antenna device in the embodiment of FIG.

FIG. 7 is a configuration diagram showing a first conventional example of an antenna device used for automatic tracking.

FIG. 8 is a configuration diagram showing a second conventional example of an antenna device used for automatic tracking.

[Explanation of symbols]

 1 circularly polarized wave generator 3 rotary joint 5 primary radiator 7 reflecting mirror 9 vertical rotation axis 11 horizontal rotation axis

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[Procedure amendment]

[Submission date] March 25, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0037

[Correction method] Change

[Correction contents]

In FIG. 6, θa = θam (constant) and Ax = A
The gain Gm (θ, θam, A when x'is constant)
It shows an image of changes in x ', yh). further,
The graph of each position Ax (0 ≦ Ax ≦ 1) of the rotary shaft 9 is calculated by setting Ax = Ax ″ (constant). From the graph, the position Ax of the rotary shaft 9 (vertical in claim 1) The variation of the gain Gm with respect to the beam deflection angle θ is controlled by combining the arrangement position of the rotation axis) and the vertex coordinate value yh of the primary radiator 5 (the arrangement position of the primary radiator in claim 1). I know that I can do it.

Front page continuation (72) Inventor Kazuyoshi Masagen 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Norihiko Yazawa 1-10-11 Kinuta, Setagaya-ku, Japan Japan Broadcasting Technology Institute of Broadcasting Technology

Claims (5)

[Claims] 1. A circular polarization generator for converting a linear polarization signal into a circular polarization signal, a primary radiator for radiating the circular polarization signal from the circular polarization generator, and this primary radiator. A reflection mirror that converts the radiation wave from the plane wave into a plane wave and reflects it; and a vertical rotation axis that controls the beam deflection angle by rotating the reflection mirror in the vertical direction. The horn reflector antenna device is characterized in that the combination with the arrangement position of the rotating shaft is set to a combination that maximizes the gain. 2. A circular polarization generator for converting a linear polarization signal into a circular polarization signal, a primary radiator for radiating the circular polarization signal from the circular polarization generator, and this primary radiator. A reflection mirror that converts the radiation wave from the device into a plane wave and reflects it; and a vertical rotation shaft that controls the beam deflection angle by rotating the reflection mirror in the vertical direction. A horn reflector antenna device, wherein a combination with a disposition position of the primary radiator is set to a combination in which a gain variation with respect to a beam deflection angle is minimized. 3. A circular polarization generator for converting a linear polarization signal into a circular polarization signal, a primary radiator for radiating the circular polarization signal from this circular polarization generator, and this primary radiator. A reflection mirror that converts the radiation wave from the plane wave into a plane wave and reflects it; and a vertical rotation axis that controls the beam deflection angle by rotating the reflection mirror in the vertical direction. The combination of the arrangement position of the rotating shaft and the arrangement position of the primary radiator is set such that the gain is maximum and the gain variation with respect to the beam deflection angle is minimum. Antenna device. 4. The horn reflector antenna device according to claim 1, 2 or 3, wherein a second circularly polarized wave generator is interposed between the circularly polarized wave generator and the primary radiator. Characteristic horn reflector antenna device. 5. The horn reflector antenna device according to claim 1, 2, 3 or 4, wherein a horizontal rotation shaft for rotating the reflecting mirror in a horizontal direction is provided.