RU2446523C1 - Multibeam single-reflector antenna for receiving signals from satellites on edge of visible geostationary orbit sector - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: disclosed is a multi-beam antenna, having a reflector which is a cut of a portion of a surface formed by turning a parabola about an axis lying in the plane of the parabola and perpendicular to the focal axis of the parabola, and a line or radiators lying on the middle of the radius of rotation and at the focal point of the parabola. Said portion is cut from a surface formed by turning a parabola about an axis inclined at an angle equal to the angle of inclination of serviced section of the geostationary orbit to the horizon line, to the normal to the plane passing through the point where the antenna is located and two points lying infinitely near to centre of the serviced section of the geostationary orbit such that the top and bottom edges of the reflector lie in parallel to said plane, and the line of radiators is inclined to said plane.

EFFECT: high gain of the multibeam single-reflector antenna which is specifically meant to receive signals from satellites located on the edge of the visible section of the geostationary orbit, which does not need to be inclined to the earth's surface.

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Description

The invention relates to antennas and is intended for use as part of radio engineering satellite communications devices in the VHF and UHF bands.

Known designs of multi-beam mirror antennas that allow the formation of several deviated diagrams in a certain sector of angles (US Pat. RU 2380802, H01Q 19/19, 2336615, H01Q 15/00, 2181519, H01Q 19/18, 2342748, H01Q 19/10, US Pat. U.S. 4,786,910; H01Q 25/100).

Of the known structures, the closest in technical essence is the multi-beam antenna (MLA), described in the article by Somov and Babintsev “Multi-beam mirror antenna for satellite communication systems” (collection of scientific articles “Transactions of NIIR”, 2010, No. 1, p. 35- 42), which is capable of receiving signals simultaneously from each of several artificial Earth satellites (AES) located in a geostationary orbit (GSO) through a partial diagram (beam). The antenna contains a parabolic mirror having a rectangular aperture shape and formed by cutting from a reflector formed by rotation of the parabola, and an array of irradiators located in the foci of the mirror.

One of the disadvantages of such an MDA design is the inconvenience of receiving signals from satellites located on the "edges" of the visible sector of the GSO, which is expressed in the fact that the antenna must be placed at an angle to the earth's surface.

The technical result consists in providing a high gain of a multi-beam single-mirror antenna, specially designed for receiving signals from "edge" satellites, which does not need to be installed obliquely to the earth's surface.

The specified technical result is achieved by the fact that a multi-beam antenna is proposed that contains a mirror, which is a notch of a part of the surface from the surface formed by the rotation of the parabola around an axis lying in the plane of the parabola and perpendicular to the focal axis of the parabola, and a line of irradiators located in the middle of the radius of rotation and in focus of the parabola, moreover, the notch is made from the surface formed by the rotation of the parabola relative to the axis inclined at an angle equal to the angle of inclination of the serviced the geostationary orbit is connected to the horizon line, to the normal to the plane passing through the antenna placement point and two points infinitely close to the center of the serviced geostationary orbit section, so that the upper and lower edges of the mirror are parallel to the specified plane, and the line of the irradiators is inclined to the specified plane .

In a Cartesian coordinate system, the surface of an MDA mirror is described by the following formula:

where α is the angle of inclination to the horizon line of the served visible portion of the GSO; R _З - radius of the circle of the antenna mirror; D _L - the size of the aperture of the antenna in the longitudinal plane; D _T - the size of the aperture of the antenna in the transverse plane; x, y, z - coordinates. The origin is the location of the "central" feed, receiving a signal from a satellite located in the middle of the served GSO sector.

The line location of the phase centers of the antenna feeds in the same Cartesian coordinate system is described by the formula:

When aiming the irradiator at a serviced satellite, due to the nonlinearity of the visible portion of the GSO, the phase center of the irradiator will be slightly separated from the above line, which leads to a slight decrease in the antenna gain.

To explain the device of the proposed antenna, FIG. 1 is used — an image of the antenna in a Cartesian coordinate system in three different projections, FIG. 2 — a parabola and an axis of rotation, FIG. 3 — a visible portion of a GSO, FIG. 4 — arrangement of radiation patterns, FIG. 5 — ray path in geometrical optical representation.

The antenna contains a reflector 1 and a line of irradiators, the phase centers of which are located on line 2 (figure 1). Figure 1 also shows the axis of rotation 3.

The mirror (reflector) 1, used to form the field of the reflected wave with a flat phase front in the transmission mode or quasispherical wave in the reception mode, is made in the form of cutting out a part of the surface from the surface formed by the rotation of the parabola relative to an axis lying in the plane of the parabola and perpendicular to its focal axis (Fig.2), inclined at an angle α to the normal to the plane passing through the point of placement of the antenna and two infinitely close to the center of the served area (Fig.3) of the geostationary orbit of the point. Moreover, the upper and lower edges of the mirror are parallel to the specified plane. The angle α is equal to the angle of inclination of the serviced GSO section (Fig. 3) to the horizon line.

The line of irradiators, the phase centers of which are located on line 2 (Fig. 1), consists of irradiators, which can be used as horn, spiral, slot, and other single or group (cluster) emitters, which does not affect the essence of the proposed solution, but with a phase or "partial phase" center. Line 2 is located in the plane of rotation of the focal axis of the parabola and is part of a circle with radius R _З / 2 and centered on the axis of rotation 3. The plane of location of line 2 is inclined to the plane passing through the antenna location point and two infinitely close to the center of the geostationary serving section orbits of a point, at an angle α.

The proposed antenna for transmission works as follows (figure 5). Each irradiator emits an electromagnetic field with a spherical phase front within the opening angle of the reflector. The geometrical optical rays of these fields are reflected at the corresponding points of the mirror and form reflected waves with a flat phase front. The locations and orientations of the irradiators relative to the mirror are determined by the location of the served satellites on the GSO.

In the reception mode, the proposed antenna operates as follows (figure 5). Geometrical optical rays of partial radiation patterns arriving at the mirror in the form of waves with a flat phase front are reflected from the mirror, concentrating at the focus of the mirror, where the phase center of the irradiator is established.

The present invention allows to form a set of partial radiation patterns, an example of which is shown in figure 4. In the figure, the abscissa shows the angles in radians, and the ordinate shows the level of the radiation pattern in dB.

The present invention allows to receive signals from satellites located on the edge of the visible portion of the GSO, without the need to tilt the antenna to the horizon.

Various modifications of the invention are possible, which does not change the essence of the structure under consideration, i.e. The solution claimed in the invention is common for single-mirror antennas forming a multi-beam pattern.

Information sources

1. Somov A.M., Babintsev A.V. Multipath Mirror Antenna for Satellite Communication Systems // Transactions of NIIR. - 2010. - No. 1. - S. 35-42.

2. Eisenberg G. 3., Yampolsky V.G., Tereshin O.N. VHF antennas. Part 1. - M .: Communication, 1977 .-- 382 p.

3. Eisenberg G. 3., Yampolsky V.G., Tereshin O.N. VHF antennas. Part 2. - M.: Communication, 1977 .-- 288 p.

Claims (1)

A multi-beam antenna containing a mirror, which is a notch of a part of the surface from a surface formed by the rotation of a parabola around an axis lying in the plane of the parabola and perpendicular to the focal axis of the parabola, and a line of irradiators located in the middle of the radius of rotation and in the focus of the parabola, characterized in that the notch is carried out from the surface formed by the rotation of the parabola relative to the axis inclined at an angle equal to the angle of inclination of the serviced portion of the geostationary orbit to the horizon line, to the nor small to a plane passing through the antenna placement point and two points infinitely close to the center of the serviced portion of the geostationary orbit, so that the upper and lower edges of the mirror are parallel to the indicated plane, and the line of the irradiators is inclined to the specified plane.

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