JP2705612B2 - Beam-fed double reflector 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 beam-feeding double-reflector antenna sharing a plurality of frequencies, and more particularly, to a beam-feeding antenna capable of reducing the size and weight of a feeding portion and mounting it on an artificial satellite. Type double reflector antenna.

[0002]

2. Description of the Related Art A beam-feeding double reflector antenna has a small feeding loss and a feeding system (feeding horn and plane mirror).
Has the advantage of being able to cope with a wide range of frequency bands, and is now widely used in the tracking of artificial satellites at ground stations, radio telescopes for astronomical observation, and the like.

FIG. 4 is a conceptual diagram showing a beam-fed double reflector antenna used in a conventional ground station. In FIG. 1, reference numeral 101 denotes a feed horn, which radiates radio waves of a low frequency (for example, S band) and a high frequency (for example, Ka band) shared by an antenna.

Reference numeral 102 denotes a power supply unit, which includes first and second plane mirrors 102a and 102d and first and second parabolic mirrors 102.
b, 102c. The power supply unit 102 transmits a low-frequency or high-frequency radio wave from the power supply horn 101 to the first plane mirror 102a → the first parabolic mirror 102b → the second parabolic mirror 102c → the second plane mirror 102
The light was reflected by the sub-reflection mirror 103 in the order of d.

[0005] The sub-reflector 103 is configured to reflect low-frequency and high-frequency radio waves from the power supply unit 102 to the main reflector 104. And the main reflecting mirror 104
Upon receiving the radio wave from the sub-reflector 103, the antenna beam of the low frequency and the high frequency was radiated.

Here, the sizes of the first and second plane mirrors 102a and 102d and the first and second parabolic mirrors 102b and 102c which form the power supply unit 102 are lower than a plurality of frequencies shared by the antenna. Determined by frequency. That is, in order to reflect radio waves to the first and second plane mirrors 102a, 102d, etc., generally, an aperture diameter that is 10 times or more the wavelength of the working frequency is required. For example, in the case of a beam-fed double reflector antenna sharing the S band (low frequency) = 2 GHz and the Ka band (high frequency) = 20 GHz, the size of the first and second plane mirrors 102a and 102d is 10 · λ = approximately 1.5 m (Note that Ka
First and second plane mirrors 102a, 102d required for band
Is 10 · λ = about 150 mm). Here, λ indicates a free space wavelength.

In recent years, such a beam-fed double-reflector antenna has been considered to be promising as an antenna for mounting on a satellite, because it has the advantage of a high-efficiency antenna with a small feeding loss. It is expected that a beam-fed double reflector antenna that can be mounted on an artificial satellite (data relay satellite) that tracks satellites from a geosynchronous satellite orbit and relays data will be put to practical use.

[0008]

However, in the above-described conventional beam-fed double-reflector antenna, the power feeding section 102 is required.
The size of the first and second plane mirrors 102a, 102d, etc., which form the first and second plane mirrors 102a, 102d, is determined by the lower frequency among the plurality of frequencies used for communication. Become larger,
There is a problem that the entire power supply unit 102 is large and heavy. For this reason, it is impossible to mount a conventional beam-fed double reflector antenna on a data relay satellite, and there is no artificial satellite with a beam-fed double reflector antenna at present.

Therefore, in today's communication and broadcasting technology satellite in Japan, an inter-satellite communication antenna 20 as shown in FIG.
0 is used to relay data (see IEICE Space and Electronics Research Group, "Comets (Communications and Broadcasting Satellite)" August 1993).

In FIG. 1, this inter-satellite communication antenna 2
Reference numeral 00 denotes an RF compartment 202 in which a high-frequency device for relay (not shown) is attached to the back of the main reflecting mirror 201.
The main reflecting mirror 201 and the RF compartment 202 are driven together to perform tracking of another artificial satellite.

However, such an inter-satellite communication antenna 2
In the case of 00, an RF compartment 202 accommodating a high-frequency device for relay or the like must be provided on the back surface of the main reflecting mirror 201, which increases the weight of the inter-satellite communication antenna 200 and a driving system for driving the antenna. There is a problem that the size is increased and power consumption is increased.

Although it is not a beam-fed double reflector antenna, Japanese Patent Application Laid-Open No. 63-2408 discloses a frequency-selective sub-reflector that transmits a high-frequency radio wave and reflects a low-frequency radio wave. A first power supply horn provided on the back side of the type sub-reflector and radiating the high frequency radio wave, and a second power supply horn provided on the front side of the frequency selective type sub-reflector and radiating the low frequency radio wave A power supply horn and a part of the outer periphery formed by a frequency selection plate, and a main reflector for reflecting a radio wave reflected or transmitted by the frequency-selection type sub-reflector for use in a satellite-mounted configuration. Multi-frequency shared antennas have been proposed.

According to such a multi-frequency antenna disclosed in JP-A-63-2408, one multi-frequency antenna can be used as an offset parabolic antenna and an offset Cassegrain antenna depending on the frequency used.
Power can be supplied from different focal points when used as an offset parabolic antenna and when used as an offset Cassegrain antenna.

However, Japanese Patent Application Laid-Open No. 63-2
Since the multi-frequency antenna of No. 408 does not have a feed portion (plane mirror) in the beam-fed double reflector antenna, the beam-fed double reflector antenna is mounted on the satellite even if this technology is applied as it is. It is not possible.

In addition, Japanese Patent Application Laid-Open Nos. 63-9092 and 62-3510 propose a multi-frequency antenna for use on a satellite. It does not solve the problem.

The present invention has been made in view of the above problems, and can reduce the size and weight of a power supply unit.
An object of the present invention is to provide a beam-fed double reflector antenna that can be mounted on an artificial satellite.

[0017]

In order to achieve the above object, a beam-fed double reflector antenna according to claim 1 is provided.
A main reflector and a frequency-selective sub-reflector disposed in front of the focal point of the main reflector and transmitting low-frequency radio waves among a plurality of frequencies shared by the antenna and reflecting high frequencies to the main reflector. A mirror, a first power supply horn disposed on the back side of the frequency-selective sub-reflector, and disposed at a focal point of the main reflector, and emitting a radio wave of a lower frequency among the plurality of frequencies; and Out of the second feed horn, and a beam feed type duplexer having two plane mirrors for reflecting the high frequency radio wave from the second feed horn to the frequency selective type sub-reflector.
In the reflector antenna, the two plane mirrors are doubled.
It is rotatable around the AZ axis and EL axis into the constructed lens barrel
There is a configuration in which it is stored .

According to a second aspect of the present invention , in the beam-feeding double-reflecting mirror antenna, the doubly-configured lens barrel is provided around the AZ axis.
The outer barrel that is rotatable to the inside and the inside of this outer barrel
An inner lens barrel that is rotatable about the EL axis;
Are arranged vertically inside the inner lens barrel .

[0019]

[Action] <br/> beam powered double reflector antenna of the present invention, among the frequency sharing, when performing communication by a low frequency, the beam-powered double reflector antenna acts as a parabolic antenna . That is, the low-frequency radio wave radiated from the first feeding horn is transmitted through the frequency-selective sub-reflecting mirror and is irradiated on the main reflecting mirror.

When communication is performed at a high frequency, the present beam-fed double reflector antenna functions as a beam-fed Cassegrain antenna. That is, the high frequency radio wave radiated from the second power supply horn is reflected by the plane mirror, and the radio wave course is changed. The high-frequency radio wave reflected by the plane mirror is reflected by the frequency-selective sub-reflector and radiated to the main reflector.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An example of a Na will be described with reference to the drawings. FIG. 1 is a perspective view showing a beam-fed double reflector antenna according to an embodiment of the present invention. FIG. 2A is a side view of the beam-fed double reflector antenna, and FIG. 2B is a front view. Further, FIG. 3A is a front sectional view showing a feeding portion of the beam-feeding double reflector antenna, and FIG. 3B is a side sectional view.

First, an embodiment of the beam feeding type double reflector antenna according to the present invention will be described. The beam feeding type double reflector antenna of this embodiment has a configuration in which the main reflector is offset from the first and second feeding horns, and is mounted on a data relay satellite in a geosynchronous orbit.

In FIGS. 1 and 2A and 2B, 1
Is a satellite structure, which has an earth-facing panel 1a, an east panel 1b, a north panel 1c, and a south panel 1d. A main reflector 10 is provided on the east panel 1b of the satellite structure 1. This main reflecting mirror 10 is connected to a boom 11 (FIG. 3A,
(Refer to (b)).

In front of the focal point of the main reflecting mirror 10, a frequency-selective sub-reflecting mirror 20 connected to the boom 11 via a frame.
Is arranged. This frequency-selective sub-reflector 20 is different from the frequency-selective sub-reflector used in a multi-frequency antenna such as the conventional Japanese Patent Application Laid-Open No. 63-2408. It is configured to transmit radio waves and reflect high frequency radio waves to the main reflector.

That is, the frequency selective type sub-reflector 20 is
A metal patch (reflector) that reflects high frequencies is formed on a material that has radio wave transparency so that a predetermined high frequency is reflected. High frequency radio waves are reflected by this patch portion, and low frequency radio waves are reflected. It is transmitted.

A first power supply horn (S-band power supply unit) 30 is mounted on the back side of the frequency selective type sub-reflection mirror 20 and at the focal point of the main reflection mirror 10. The first feeding horn 30 is connected to a receiver and a transmitter (not shown) housed in the satellite structure 1 and emits a radio wave of a lower frequency among a plurality of frequencies shared by the antenna. .

As shown in FIGS. 1, 2 (b) and 3 (a), a second power feeding horn (Ka band power feeding portion) 40 is provided beside the power feeding portion 50. The opening of the second power supply horn 40 is the Y-axis plane mirror 5 of the power supply unit 50.
3 and is connected to a receiver 60 and a transmitter 70 housed in the satellite structure 1. Then, such a second feeding horn 40 emits a radio wave of a higher frequency among a plurality of frequencies shared by the present antenna.

As shown in FIGS. 3A and 3B, the power supply unit 50 includes an outer lens barrel 51, an inner lens barrel 52, a Y-axis flat mirror 53, an X-axis flat mirror 54, a Y-axis motor 55, and an X-axis motor 55. It comprises a motor 56.

3A and 3B, the outer lens barrel 5 is shown.
Reference numeral 1 denotes a Y-axis (AZ) formed by a rotating shaft of a Y-axis motor 55 fixed to the east panel 1b via a support member 41 and a bearing 41a of a second power supply horn 40 provided on the support member 41.
It is supported rotatably around the axis.

Inside the outer lens barrel 51, the inner lens barrel 5 is provided.
2 is attached so as to be rotatable around the X axis (EL axis).
A Y-axis plane mirror 53 is fixed below the inside of the inner lens barrel 52, and an X-axis plane mirror 54 is fixed at a predetermined angle above the inside. The bottom of the inner lens barrel 52 is connected to the outer lens barrel 51.
, And is connected to the rotation shaft of an X-axis motor 56 fixed thereto.

Further, the above-described boom 11 is joined to the back surface of the X-axis plane mirror 54, and in conjunction with the rotation of the outer lens barrel 51 and the inner lens barrel 52 around the Y axis by the Y-axis motor 55, The main reflecting mirror 10, the frequency-selective sub-reflecting mirror 20, and the first feeding horn 30 rotate around the Y axis, and in conjunction with the rotation of the inner barrel 52 around the X axis by the X-axis motor 56, The main reflecting mirror 10, the frequency-selective sub-reflecting mirror 20, and the first feeding horn 30 are configured to rotate around the X axis.

Here, the pointing operation of the power supply unit 50 will be described. The high frequency radio wave radiated from the second power supply horn 40 is radiated to the Y-axis plane mirror 53,
Is reflected by the X-axis plane mirror 54. The radio wave applied to the X-axis plane mirror 54 is
The light is reflected to 0 and irradiates the main reflecting mirror 10. Thereby, the antenna beam is radiated from the main reflecting mirror 10.

At this time, when the outer lens barrel 51 is driven to rotate about the Y axis by the Y-axis motor 55, the inner lens barrel 52 also rotates about the Y axis in conjunction therewith, and is fixed to the inner lens barrel 52. Y-axis plane mirror 53, X-axis plane mirror 54, boom 1
1. All of the frequency-selective sub-reflecting mirror 20 and the main reflecting mirror 10 rotate around the Y-axis, and the angle of the antenna beam radiated from the main reflecting mirror 10 about the Y-axis changes.

The X-axis motor 56 controls the inner lens barrel 52
Is rotated about the X-axis, all of the Y-axis plane mirror 53, the X-axis plane mirror 54, the boom 11, the frequency-selective sub-reflecting mirror 20, and the main reflecting mirror 10 are rotated about the X-axis, and the main reflecting mirror 1 is rotated.
The angle about the X axis of the antenna beam radiated from 0 changes.

As described above, the outer lens barrel 51 and the inner lens barrel 52 are appropriately rotated by the Y-axis motor 55 and the X-axis motor 56 to direct the antenna beam to a desired angle.

Next, a method of using the beam feeding type double reflector antenna having the above-described configuration will be described.

First, when communication is performed at a lower frequency among the shared frequencies, the present beam-fed double reflector antenna is used as an offset parabolic antenna.
That is, when a low-frequency radio wave is emitted from the first feeding horn 30, this radio wave is
Is transmitted to the main reflecting mirror 10. As a result, a low-frequency antenna beam is radiated from the main reflecting mirror 10.

When communication is performed at a high frequency, the present beam-fed double reflector antenna is used as a beam-fed offset Cassegrain antenna. That is, when a high-frequency radio wave is emitted from the second power supply horn 40, the radio wave is reflected by the Y-axis and X-axis plane mirrors 53 and 54 of the power supply unit 50, and the radio wave course is changed.

The radio wave reflected from the power supply unit 50 is reflected by the frequency-selective sub-reflecting mirror 20 and is reflected by the main reflecting mirror 1.
It is irradiated to 0. Thereby, a high-frequency antenna beam is radiated from the main reflecting mirror 10.

According to such a beam-powered double reflector antenna of the present embodiment, among the frequency sharing, the radio waves of low frequency (S-band), the feeding unit 50 (Y-axis plane mirror 53
And the X-axis plane mirror 54) and the X-axis plane mirror 54).
Can be determined based on radio waves of a high frequency (Ka band).

As a result, the opening diameters of the Y-axis plane mirror 53 and the X-axis plane mirror 54 can be reduced, and the power supply unit 50 including the Y-axis plane mirror 53 and the X-axis plane mirror 54 can be reduced in size and weight. A beam-fed double reflector antenna can be mounted on a data relay satellite. Therefore,
By changing the feed system (feed horn and plane mirror) with a small feed loss, the effect of the beam feed type double reflector antenna that can support a wide frequency band can be reflected on the data relay satellite.

When the present inventor actually manufactured the power supply unit 50 based on the above embodiment, the power supply unit 50 was manufactured.
With the width in the Y-axis direction = 720 mm and the height in the X-axis direction = 620
mm. This is about 1 / approximately compared to a conventional power supply unit with a built-in flat mirror with an aperture diameter of 1.5 m.
The size is 10 or less.

In the present embodiment, the low-frequency radio wave is fed as an offset parabolic antenna without beam feeding and without being reflected by the sub-reflecting mirror 20. Therefore, there is no problem such as a decrease in antenna gain.

On the other hand, at a high frequency where the feed loss is large,
Since the configuration is such that the beam is fed as an offset Cassegrain antenna of the beam feeding type, good characteristics can be obtained.

[0045] The beam-powered double reflector en <br/> Te Na of the present invention is not limited to the above embodiments. For example, in the above embodiment, the main reflector is offset from the first and second feed horn, a configuration for use as off set parabolic antenna or offset Cassegrain antenna, which is not particularly limited, usually it is also possible to change the <br/> configuration to use as parabolic antenna or Cassegrain antenna.

[0046]

As described in the foregoing, according to the beam-powered double reflector antenna of the present invention, AZ axis and EL Jikukai
Two flat mirrors that rotate
Since it is constituted, it is possible to reduce the size and weight of the power supply unit including a flat surface mirror. This makes it possible to mount the beam-fed double reflector antenna on a data relay satellite.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a beam-fed double reflector antenna according to an embodiment of the present invention.

FIG. 2A is a side view of the beam-fed double reflector antenna, and FIG. 2B is a front view.

FIG. 3A is a front sectional view showing a feed section of the beam-feeding double reflector antenna, and FIG. 3B is a side sectional view.

FIG. 4 is a conceptual diagram showing a beam-fed double reflector antenna used in a conventional ground station.

FIG. 5 is a perspective view showing a conventional data relay satellite.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Satellite structure 1a Earth-facing panel 1b East panel 1c North panel 1d South panel 10 Main reflector 11 Boom 20 Frequency selective type sub-reflector 30 First feeding horn (S-band feeding horn) 40 Second feeding horn (Ka band) Power supply horn) 41 support member 41a bearing 50 power supply unit 51 outer lens barrel 52 inner lens barrel 53 Y-axis plane mirror 54 X-axis plane mirror 55 Y-axis motor 56 X-axis motor 60 receiver 70 transmitter

Claims (2)

(57) [Claims] 1. A main reflector, which is disposed in front of a focal point of the main reflector and transmits a low-frequency radio wave among a plurality of frequencies shared by an antenna and reflects a high frequency to the main reflector. A frequency-selection type sub-reflector, and a first power supply horn that is disposed on the back side of the frequency-selection type sub-reflector and at the focal point of the main reflection mirror and emits a radio wave of a lower frequency among the plurality of frequencies; A second power supply horn that emits a radio wave of a higher frequency among the plurality of frequencies, and two plane mirrors that reflect the radio wave of a higher frequency from the second power supply horn to the frequency-selective sub-reflector.
In the beam feeding type double reflector antenna, the two plane mirrors are placed in a double-structured lens barrel by the AZ axis.
And a beam-feeding double-reflecting mirror antenna housed rotatably about an EL axis . 2. The apparatus according to claim 2, wherein said double-barreled lens barrel is provided around an AZ axis.
The outer barrel that is rotatable to the inside and the inside of this outer barrel
An inner lens barrel that is rotatable about the EL axis;
2. The device according to claim 1, wherein the first and second members are arranged in a vertical direction inside the inner lens barrel.
Beam-fed double reflector antenna.