JPH0716131B2 - Multi-beam antenna for satellite - Google Patents

Description

The present invention relates to a satellite-mounted multi-beam antenna mounted on an artificial satellite and used for communication with a land mobile body.

(Prior Art) Conventionally, as a multi-beam antenna of this kind, there are literatures, RPCox, J. Zacharatos, B. Williamson, C. Morgan and
JRGCox: “System trade off for a north american
mobile satellite ", AIAA, 88-0845 (1988) (see FIGS. 7 and 8), reference, AMKidd, HJM
oody and H. Raine: “System design of the canadian m
obile communication satellite ", AIAA, 86-0661 (198
6) (see Fig. 9), reference, Miyasaka, Otsu, Takamura: "Study on land mobile satellite communication system in the stationary platform era", IEICE Tech., A.P88-155, SAT88- 9
7 (1989-02) (see FIG. 10) is known.

In the above, FIG. 7 shows a multi-beam antenna, FIG. 8 shows a beam arrangement in North America, and in FIG. 7, 1 is a satellite body, 2 is a primary transmitter for transmission,
3 is a primary radiator for reception, 4 is a reflector for a transmission antenna, 5
Is a reflector for a receiving antenna, 6 is a solar array paddle,
In this antenna, the transmitting antenna reflecting mirror 4 and the receiving antenna reflecting mirror 5 have the same size and the same shape, and the transmitting primary radiator 2 and the receiving primary radiator 3 are arrayed with a plurality of horn antennas. It is composed of an antenna.

Further, in FIG. 8, 7a, 7b ... 7n represent circular beams irradiating North America, and these circular beams 7a, 7b ... 7n.
Has the same beam shape for both transmission and reception.

In the above, FIG. 9 shows the beam arrangement of the elliptical beam for North America which was originally considered for the beam arrangement of FIG. 7 above, and 8a, 8b ... 8n in the figure show the elliptical beam. Has the same shape for both transmission and reception, and the major axis direction of each elliptical beam is the north-south direction.

The above is an example of a beam arrangement of a multi-beam antenna for mobile communication in Japan, which is shown in FIG. 10 as 9a, 9b ... 9
n indicates a circular beam having the same shape for both transmission and reception.

[Problems to be Solved by the Invention] However, in the case where the irradiation area spreads in the north, south, east, and west as shown in FIG. 8 and FIG. 9 of the above-mentioned prior art, a circular beam or an elliptical beam close to a circle is efficient. Irradiation is possible, but if the irradiation area is long and narrow, as in the Japanese archipelago shown in Fig. 10, the circular beam and the elliptical beam having a long axis in the north-south direction shown in Fig. 9 will often irradiate the sea. There was a problem that the efficient irradiation of only the Japanese archipelago could not be done.

Further, in the case of the circular beam shown in FIGS. 8 and 10, there is a problem that the number of frequency reuses does not increase because one beam has many adjacent beams.

On the other hand, in the case shown in FIG. 9, since the number of beams adjacent to one beam is only the beams on both sides, the frequency reuse frequency increases, but in this case, the transmission beam viewed from the satellite side is increased. Since the receiving beam and the receiving beam have the same shape, there is a problem that the ground mobile station is not downsized as compared with the case where the beam width of the receiving beam is narrowed.

Further, if the satellite receiving antenna is made large in order to make the terrestrial mobile device small and the transmitting antenna is made the same size as the receiving antenna, there is a problem that the weight of the entire satellite-mounted antenna becomes very heavy.

Therefore, the present invention enables efficient irradiation even when the irradiation area is long and narrow as in the Japanese archipelago, increases the frequency of frequency reuse, and enables downsizing of the ground mobile device, and the weight of the entire antenna. It is an object of the present invention to provide a multi-beam antenna for a satellite that does not increase in power consumption.

(Means for Solving the Problems) A multi-beam antenna for mounting a satellite according to the present invention is a multi-beam antenna for mounting a satellite, which is independently provided with a transmitting antenna and a receiving antenna, and radiates an elliptical beam from the transmitting antenna. While comprising a multi-beam antenna, the receiving antenna is configured by a multi-beam antenna that is orthogonal to the elliptical beam from the transmitting antenna and radiates an elliptical beam smaller than the elliptical beam from the transmitting antenna. Has become.

(Operation) In the multi-beam antenna of the present invention, the transmitting antenna radiates an elliptical beam, and the transmitting antenna radiates a small elliptical beam orthogonal to the elliptical beam of the transmitting antenna.

In this case, the beams radiated from the transmitting antenna and the receiving antenna are both elliptical beams. Even in the irradiation region, efficient irradiation can be performed, and the beams adjacent to each beam can be only on both sides, and the frequency reuse frequency can be increased.

Furthermore, since the elliptical beam of the receiving antenna is made orthogonal to the beam of the transmitting antenna and is made small, it is possible to downsize the ground mobile device and to keep the size of the transmitting antenna small. It is possible to prevent an increase in the weight of the entire antenna mounted on the satellite.

(Example) An example of the present invention will be described below.

FIG. 1 shows a multi-beam antenna 10 for mounting on a satellite according to this embodiment. 11 is a satellite body, 12 is an elliptical beam primary radiator for transmission, 13 is an elliptical beam primary radiator for reception, and 14 is a transmitting ellipse beam. A credit elliptic aperture reflecting mirror (transmitting antenna), 15 is a receiving elliptical aperture reflecting mirror (receiving antenna), and 16 is a solar cell paddle.

In the antenna 10, the beam emitted from the transmitting elliptical beam primary radiator 12 is transmitted by the transmitting elliptical aperture reflector.
The ellipse-shaped multi-beam is emitted toward a predetermined region of the earth by the elliptical aperture reflecting mirror 14. On the other hand, it is radiated from the receiving elliptical beam primary radiator 13 through the receiving elliptical aperture reflecting mirror 15.

The transmitting elliptical beam primary radiator 12 and the receiving elliptical beam primary radiator 13 are described in, for example, the literature, E. Lier “Br.
oad-Band elliptical beamshape horns with low cross
polarization '' IEEE Trans.vo138, no.6, pp800-805 (J
un, 1990), you may arrange multiple horns that radiate an elliptical beam, or you can arrange multiple ordinary element antennas of circular polarization, Of these element antennas, the element antenna within the ellipse corresponding to the beam can be used for excitation or reception.

When the multi-beam antenna 10 of this embodiment is applied to the Japanese archipelago, as shown in FIG. 2, the transmitting elliptical beam reflectors 14 are used to transmit the respective elliptical beams 17a, 17b ... 17n.
Is transmitted while the receiving elliptical aperture reflecting mirror 15 emits each of the receiving elliptical beams 18a, 18b ... 18n.

FIG. 2 shows a beam arrangement in the Japanese archipelago by the multi-beam antenna 10 of this embodiment. In this case, the elliptical beams for transmission 17a, 17b ... 17n have their major axes oriented in the east-west direction,
In addition, the beam width is set wide so that it can efficiently cover the Japanese archipelago except southern Kyushu.

Therefore, in the elliptical beams for transmission 17a, 17b, ... 17n, the antenna gain decreases, but the satellite EIRR can be maintained by increasing the transmission power. Also, the receiving elliptical beam 18
The major axes of a, 18b ... 18n are oriented in the north-south direction and the beam width is set narrow.

The long axis is oriented north-south to cover the Japanese archipelago efficiently, and the beam width is narrowed to enable downsizing of the terrestrial mobile unit, that is, even if the antenna gain of the terrestrial mobile unit is small. This is because the transmission power is good and the transmission power may be low.

Therefore, in order to make the terrestrial mobile unit compact, the receiving antenna may be large or the transmitting antenna may be small, so that it is possible to prevent the weight of the entire antenna from increasing.

In this embodiment, the receiving elliptical beams 18a, 18b ... 18n are
Although there is considerable overlap, this may be achieved by sharing a plurality of element antennas constituting the primary radiator with adjacent beams, as shown in the above-mentioned document related to FIG. 7 of the related art.

Further, according to the multi-beam antenna 10 of the present embodiment, the elliptical beams can be adjacent to each other only on both sides, so that the frequency reuse frequency can be increased.

For example, in the case of the transmission elliptical beams 17a, 17b ... 17n, the frequency reuse count is “the number of beams / the number of frequencies used = 9/1 = 9” as shown in FIG.

In the case of the receiving elliptical beams 18a, 18b ... 18n, the frequency reuse count is “21/2 = 10.5” as shown in FIG.

Therefore, a comparison will be made with the conventional case shown in FIG.

FIG. 5 shows the beam arrangement of the conventional transmitting / receiving circular beams 19a, 19b ... 19n corresponding to this embodiment, and the diameter of the conventional transmitting / receiving circular beams 19a, 19b ... The length of the minor axis of the credit elliptical beams 17a, 17b ... 17n and the major axis of the receiving elliptical beams 18a, 18b ... 18n are the same. In the conventional beam arrangement in this case, the frequency reuse frequency is , "15/2 = 7.5".

Therefore, when the elliptical beam shown in FIGS. 3 and 4 is used, the frequency reuse frequency is increased as compared with the case where the conventional circular beam is used, and in this embodiment, 1.2 times to 1.4 times that of the conventional case.
It is possible to double.

In FIGS. 3 to 5, f1 and f2 indicate frequencies, a right-handed arrow indicates a right-handed circularly polarized wave, and a left-handed arrow indicates a left-handed circularly polarized wave.

Next, another embodiment of the present invention will be described with reference to FIG.

FIG. 6 shows the multi-beam antenna 20 of this embodiment. In FIG. 6, 11 is the satellite body, 16 is the solar cell paddle, and 21.
Is an array antenna for transmission and 22 is an array antenna for reception.

The transmitting array antenna 21 is an array of a plurality of transmitting element antennas 23a, 23b ... 23n, and the receiving array antenna 22 is a plurality of receiving element antennas 24a, 24b.
4n are arranged, and the receiving array antenna 22 is configured to be foldable to 1/3. Note that the transmitting element antennas 23a, 23b ... 23n and the receiving element antennas 24a, 24b.
A microstrip antenna or horn antenna formed on a dielectric substrate by etching may be used.

According to the multi-beam antenna 20 of the present embodiment, when the transmitting array antenna 21 and the receiving array antenna 22 have the shapes shown in FIG. 6, the transmitting and receiving operations as shown in FIG. It is possible to easily form multi-elliptical beams having different beam widths.

Even when the conventional circular aperture is used as the reflecting mirror, a horn that emits an elliptical beam is used, or a primary radiator that makes one elliptical beam by a plurality of horns that emit a circular beam. You only have to configure.

Further, in the case of the array system shown in FIG. 6, even if the array shape is made square or circular, if only the element antennas within the ellipse corresponding to one elliptical beam are excited or received only by those element antennas. Good.

It should be noted that both of the embodiments described above are not limited to the elliptical beam, but can be applied to an elongated beam including an ellipse or an ellipse, and similar effects can be obtained.

As described above, according to the present invention, the beams emitted from the transmitting antenna and the receiving antenna are both elliptical beams and are orthogonal to each other. Therefore, for example, even in a long and narrow irradiation region such as the Japanese archipelago, the efficiency is high. Good irradiation becomes possible.

Further, since the elliptical beams are used, they can be adjacent to each other only on both sides, and the frequency reuse frequency can be increased.

Furthermore, since the elliptical beam radiated from the receiving antenna has been made smaller, it is possible to downsize the ground mobile unit.
Even if the receiving antenna is made large, the transmitting antenna can be made small, and it is possible to prevent the weight of the entire antenna mounted on the satellite from increasing.

[Brief description of drawings]

FIG. 1 is a perspective view of a multi-beam antenna mounted on a satellite according to an embodiment of the present invention, FIG. 2 is a layout diagram of elliptical beams for transmission and reception, and FIG. FIG. 4 is a diagram showing utilization, FIG. 4 is a diagram showing frequency reuse in an elliptical beam for reception, and FIG. 5 is a diagram showing frequency reuse in a conventional circular beam for transmission / reception corresponding to the present embodiment, FIG. 6 is a perspective view of a multi-beam antenna according to another embodiment of the present invention, FIGS. 7 to 10 are related to a conventional example, FIG. 7 is a perspective view showing the multi-beam antenna, and FIG. Figure 9 is a layout of circular beams in the Americas, Figure 9 is a layout of elliptical beams in North America, and Figure 10 is a layout of circular beams in the Japanese archipelago. In the figure, 10 and 20 are multi-beam antennas, 14 and 21 are transmitting antennas, 15 and 22 are receiving antennas, 17a, 17b, ... 17n are transmitting elliptical beams, and 18a, 18b ... 18n are receiving elliptical beams. The beam.

Front page continuation (72) Inventor Toshio Sugimoto 2-12-5 Iwamoto-cho, Chiyoda-ku, Tokyo Inside Space Communications Research Laboratories, Inc. (72) Inventor Yoshikazu Doi 2--12-5 Iwamoto-cho, Chiyoda-ku, Tokyo No. Co., Ltd. Space Communication Basic Technology Research Institute

Claims (3)

[Claims] 1. A satellite-mounted multi-beam antenna having a transmission antenna and a reception antenna independently, wherein the transmission antenna comprises a multi-beam antenna that radiates an elliptical beam, while the reception antenna comprises: A multi-beam antenna for mounting on a satellite, comprising: a multi-beam antenna that is orthogonal to the elliptical beam from the transmitting antenna and emits an elliptical beam smaller than the elliptical beam from the transmitting antenna. 2. The multi-beam for mounting on a satellite according to claim 1, wherein the minor axis length of the elliptical beam of the transmitting antenna is set to be equal to the major axis length of the elliptical beam of the receiving antenna. antenna. 3. The on-board satellite according to claim 1, wherein the major axis of the elliptical beam of the transmitting antenna is set in the east-west direction, and the major axis of the elliptical beam of the receiving antenna is set in the north-south direction. Multi-beam antenna for.