JPH0691366B2 - Multi-beam antenna - Google Patents

Description

TECHNICAL FIELD The present invention relates to a satellite-mounted antenna used to cover a wide service area such as communication / broadcasting using artificial satellites with high gain. .

[Conventional technology]

FIG. 4 is a schematic diagram showing the structure of a conventional multi-beam antenna. In the figure, 1 is a single horn, 2a, 2b, 2c, 2d,
2e and 2f are array horns, 3 is a synthesis circuit for adding the inputs and outputs of array horns 2a to 2f, 4 is a parabolic reflector, and 5 is a radiation pattern when the parabolic reflector 4 is illuminated by a single horn 1. The pencil beam 6 shown is a synthetic beam represented by the sum of the pencil beams 6a to 6f by the array horns 2a to 2f. Where the pencil beam 5,
The synthetic beam 6 covers the service area A7 and the service area B8 shown in FIG. Since the service area A7 has a smaller range than the service area B8, the service area A7 determines the aperture diameter D of the parabolic reflector 4. If the wavelength used is λ, the beam width of the pencil beam 5 B _w (°)
Is approximately expressed by the following equation.

Further, the size of the single horn 1 is determined so that the irradiation level around the parabolic reflecting mirror 4 is -10 dB. The service area B8 is covered by a composite beam 6 of array horns 2a-2f consisting of a primary radiator of the same size as the single horn 1 described above.

[Problems to be solved by the invention]

Since the above-mentioned conventional multi-beam antenna is configured as described above, there is a problem that the combining circuit 3 is required to obtain the combined beam 6, and the gain is reduced due to the circuit loss of the combining circuit 3.

The present invention has been made to solve the above problems, and an object thereof is to obtain a multi-beam antenna capable of covering a service area with a high gain and a simple configuration.

[Means for solving problems]

A multi-beam antenna according to the present invention is one primary radiator that irradiates a parabolic reflector with a main beam, and another primary radiator that irradiates a parabolic reflector with a main beam and a side lobe to a side lobe region. And a parabola of a main beam and a side lobe emitted from the other primary radiator when the parabolic reflector of the main beam emitted from one primary radiator is irradiated. The second radiation pattern when irradiated by the reflecting mirror does not overlap.

[Action]

In the multi-beam antenna of the present invention, the narrower service area is covered by the pencil beam by one of the primary radiators, and the wider service area is covered by the twin beam by the other primary radiator. A wide range of service areas can be covered with high gain.

〔Example〕

FIG. 1 is a schematic diagram showing the configuration of a multi-beam antenna which is an embodiment of the present invention. In the figure, 1 is a single horn as one of the primary radiators, 4 is a parabolic reflector,
5 is a pencil beam, 9 is a sub-lobe irradiation horn (hereinafter abbreviated as S horn) as the other primary radiator, 10
Is a twin beam. Here, the single horn 1 and the pencil beam 5 are the same as the conventional one shown in FIG. The S horn 9 has a larger opening diameter than the single horn 1. When a corrugated horn is selected as the S horn 9,
Assuming that the aperture diameter is d, the half value of the angle looking into the periphery of the parabolic reflector 4 from the center of the aperture is θ _e , and the wavelength used is λ, The parameter u is set such that u> 2.5.

2 and 3 are explanatory views showing the operation of the multi-beam antenna of FIG. 1, respectively. FIG. 2 shows a radiation pattern of the multi-beam antenna of the present invention. In the figure, 5 is a pencil beam, 7 is a service area A,
8 is a service area B, and 10 is a twin beam. The pencil beam 5 and the twin beam 10 in the multi-beam antenna of the present invention respectively cover the service area A7 and the service area B8 as shown in FIG. Here, in the case of the service area B8, the gain in the service area approaches uniformly as compared with the service area B8 of the conventional multi-beam antenna shown in FIG. 5, so that the minimum gain in the service area becomes high.

FIG. 3 shows a radiation pattern of the S horn 9, which is a rotationally symmetric radiation pattern with respect to the horn axis 11 of the S horn 9. This radiation pattern is composed of a main beam 12 and a sub beam (lobe) 13, and the irradiation range extends to the sub lobe region.

In the above embodiment, if the S horn 9 is a rectangular horn, TE
_{In the 01} mode and the circular horn, the TE ₁₁ mode was set as the excitation mode, but the higher lobe modes TE ₀₂ mode and TE ₁₁ mode may be generated to control the side lobe level, and the same effect as the above embodiment can be obtained. Can play.

Further, in the above embodiment, the feed horn capable of propagating the fundamental mode and the higher order modes in the S horn 9 can be used for the S horn 9 as the other primary radiator.

In the above embodiment, the single horn 1 as one of the primary radiators and the S horn 9 as the other of the primary radiators.
May emit more than one main beam, or more than one main beam and side lobes.

〔The invention's effect〕

As described above, according to the present invention, in a multi-beam antenna, one primary radiator that irradiates a parabolic reflector with a main beam and another primary radiator that irradiates a parabolic reflector with a main beam and a side lobe to a side lobe region. Of the primary beam emitted from one of the primary radiators, and the main beam emitted from the other primary radiator, Since the second radiation pattern when the parabolic reflector of the sub-lobe is irradiated does not overlap with the second radiation pattern, the multi-beam antenna capable of covering the service area with high gain can be obtained with a simple structure. It is a thing.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a multi-beam antenna according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams showing the operation of the multi-beam antenna of FIG. 1, and FIG.
The figure is a schematic diagram showing the configuration of a conventional multi-beam antenna,
FIG. 5 is an explanatory diagram showing the operation of the multi-beam antenna of FIG. In the figure, 1 ... Single horn, 2a to 2f ... Array horn, 3 ... Synthesizing circuit, 4 ... Parabolic reflector, 5, 6a-6f ... Pencil beam, 6 ... Synthetic beam, 7 ... Service area A, 8 ... Service area B, 9 ... Sub lobe irradiation horn (S horn), 10 ... Twin beam, 11 ... Horn axis, 12 ... Main beam, 13 ... Sub beam. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] 1. An antenna comprising one parabolic reflector and two primary radiators, one primary radiator irradiating the parabolic reflector with a main beam and the other primary radiator the main beam. And a configuration in which the parabolic reflector is illuminated by a side lobe, and further, a first radiation pattern when the parabolic reflector of the main beam emitted from the one primary radiator is illuminated, and the other primary radiation A multi-beam antenna, characterized in that the main beam emitted from the vessel and the second radiation pattern of the sub-lobe when irradiated by the parabolic reflector do not overlap. 2. A primary radiator radiating two or more main beams, and another primary radiator radiating two or more main beams and side lobes. The multi-beam antenna according to item 1.