RU2805126C1 - Composite multi-beam two-mirror antenna - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention is intended for use as antennas of earth stations of satellite communication systems with satellites-relays of microwave-EHF ranges located in geostationary orbit, for simultaneous operation with several repeaters. A composite multibeam two-mirror antenna is proposed, consisting of the main (reflector) and auxiliary (counter-reflector) mirrors in the form of conductive surfaces, as well as a system of irradiators facing the counter-reflector located on a circular arc. The reflector and the counter-reflector, each, consist of three parts corresponding to each other: the central part and two additional parts adjacent to it. The shape of the surface of the central part of the reflector is formed by the rotation of a symmetrical section of the parabola, the focus of which lies in the plane of the irradiators, around an axis perpendicular to the focal axis of the parabola and passing through the centre of the circle of the irradiators arc. The shape of the surface of the central part of the counter-reflector is formed by rotating a symmetrical (with respect to the focal axis) section of a second-order curve (ellipse or hyperbola) around an axis perpendicular to the focal axis of this curve and coinciding with the axis of rotation of the parabola of the central part of the reflector. The surfaces of the additional parts of the reflector are symmetrical halves of a paraboloid obtained by rotating a section of a parabola, identical to the section forming the central part of the reflector, around the focal axis of this parabola. The surfaces of the additional parts of the counter-reflector are symmetrical halves of the second order surface obtained by rotating a section of the second order curve, identical to the section forming the central part of the counter-reflector, around the focal axis of this curve. The focal axes of the additional and central parts lie in the same plane. The first foci of the second-order curves forming the central and additional parts of the counter-reflector coincide with the foci of the parabolas forming the central and additional parts of the reflector, respectively, and the second foci of the second-order curves forming the central and additional parts of the counter-reflector lie on the arc of the irradiators.

EFFECT: increased efficiency of extreme partial beams of a multibeam two-mirror toroidal-parabolic antenna

1 cl, 1 dwg

Description

Field of technology to which the invention relates

Currently, satellite communication systems are widely used, especially those using artificial Earth satellites (AES) located in geostationary orbit (GSO). The visible portion of such an orbit contains dozens of satellites.

The present invention relates to the field of radio engineering and is intended for use as antennas for earth stations of satellite communication systems with microwave-EHF repeaters located in the geostationary orbit for simultaneous operation with several communication satellites.

State of the art

Two-mirror antennas are known [1], consisting of a main mirror (reflector) in the form of a conducting surface, which is a cutout from a paraboloid of revolution, an auxiliary (small) mirror (counter-reflector) in the form of a conducting surface, which is a cutout from an ellipsoid or hyperboloid of revolution, coaxial to the reflector , and an irradiator facing the counter-reflector and located at one of its focuses. In this case, the second focus of the counter-reflector is combined with the focus of the paraboloid.

Multi-beam two-mirror toroidal-parabolic antennas are known [2], which consist of a reflector and a counter-reflector in the form of conducting surfaces, as well as a system of feeds facing the counter-reflector located on a circular arc. In this case, the surface of the reflector is formed by rotating a section of a parabola, the focus of which lies in the plane of location of the irradiators, around an axis perpendicular to the focal axis of this parabola and passing through the center of the circle of the irradiators' arc. The surface of the counter-reflector is formed by rotating a section of a second-order curve (ellipse or hyperbola) around an axis perpendicular to the focal axis of this curve and coinciding with the axis of rotation of the parabola. The first focus of the second-order curve forming the counter-reflector coincides with the focus of the parabola, and the second focus of the second-order curve forming the counter-reflector lies on the arc of the irradiators.

The disadvantage of multi-beam toroidal-parabolic antennas is the decrease in the efficiency of the partial beam of the radiation pattern (DP) as the feed approaches the edge of the feed arc. The reason for the decrease in efficiency is an increase in the overflow of power emitted by the feed over the edges of the counter-reflector, and a corresponding decrease in the generalized utilization factor of the antenna area, as well as an increase in noise received by the antenna [3].

Disclosure of the invention

The technical result of the proposed invention is to increase the efficiency of the outer partial beams of a multi-beam two-mirror toroidal-parabolic antenna. For this purpose, a composite multibeam two-mirror antenna is proposed, consisting of a main (reflector) and an auxiliary (counter-reflector) mirrors in the form of conducting surfaces, as well as a system of feeds facing the counter-reflector located on a circular arc. In this case, the reflector and counter-reflector each consist of three parts corresponding to each other: a central part and two additional parts adjacent to it. The shape of the surface of the central part of the reflector is formed by the rotation of a symmetrical section of a parabola, the focus of which lies in the plane of location of the irradiators, around an axis perpendicular to the focal axis of the parabola and passing through the center of the circle of the irradiators' arc. The shape of the surface of the central part of the counter-reflector is formed by the rotation of a symmetrical (relative to the focal axis) section of a second-order curve (ellipse or hyperbola) around an axis perpendicular to the focal axis of this curve and coinciding with the axis of rotation of the parabola of the central part of the reflector. The surfaces of the additional parts of the reflector are symmetrical halves of a paraboloid obtained by rotating a section of the parabola identical to the section forming the central part of the reflector around the focal axis of this parabola. The surfaces of the additional parts of the counter-reflector are symmetrical halves of a second-order surface obtained by rotating a section of a second-order curve identical to the section forming the central part of the counter-reflector around the focal axis of this curve. The focal axes of the additional and central parts lie in the same plane. The first foci of the second-order curves forming the central and additional parts of the counter-reflector coincide with the foci of the parabolas, forming the central and additional parts of the reflector, respectively, and the second foci of the second-order curves forming the central and additional parts of the counter-reflector lie on the arc of the location of the irradiators.

Brief description of drawings

The invention is illustrated by the drawing FIG. 1, which indicates:

1 - reflector;

2 - counter-reflector;

3 - arc of irradiators;

4 - axis of rotation of the curves forming the central parts of the reflector and counter-reflector;

5 - parabola forming the central part of the reflector;

6, 6', 6'' - focal axes of the curves forming the reflector and counter-reflector;

7 - second-order curve (ellipse), forming a counter-reflector;

8 - arc of a circle on which the foci of the parabolas forming the reflector and the first foci of the second-order curves forming the counter-reflector lie;

9, 9' - additional parts of the reflector;

10, 10' - additional parts of the counter-reflector;

11, 12, 13 - irradiators.

Carrying out the invention

When connected to the irradiators 11, 12, 13 and the like, located on the arc of a circle 3, a generator of high-frequency oscillations, these irradiators emit a spherical wave towards the counter-reflector 2.

This wave, when reflected from the central part of the counter-reflector 2, the shape of the surface of which is formed by the rotation of a symmetrical (relative to the focal axis 6) section of the second-order curve (ellipse or hyperbola) 7, the second focus of which lies on the arc 3, around axis 4 perpendicular to the focal axis 6, a wave is transformed, which, due to the optical properties of curves and surfaces of the second order [4] in the plane containing the axis of rotation 6, seems to emanate from the first focus of curve 7. Since this focus is combined with the focus of the parabola (arc 8), then due to the optical properties of the latter , the wave going from the counter-reflector to the reflector after reflection from it is transformed into a quasi-plane wave, forming a highly directional radiation of the partial beam of the antenna with a maximum lying in the plane of the arc of the feed 3, and directed along the focal axis passing through the phase center of the corresponding feed and the axis of rotation 4. In this case, in the plane of the arc of the irradiators, after the wave is reflected from the central part of the counter-reflector 2 and then the reflector 1, quadratic phase errors occur [2], worsening the characteristics of the partial beam of the pattern, in particular, reducing the aperture utilization factor of the opening.

The spherical waves of the extreme irradiators 12 and 13 fall on the extreme regions of the central part of the counter-reflector 2, as well as on the additional parts 10 and 10' corresponding to these irradiators adjacent to the counter-reflector 2, the surfaces of which are symmetrical halves of a second-order surface obtained by rotating a section of the second-order curve, identical to section 7, which forms the central part of the counter-reflector, around the focal axis of this curve. The focal axes 6' and 6'' of the additional parts 10 and 10' lie in the same plane with the focal axes of the central part of the counter-reflector 2. Spherical waves, reflected from the additional parts 10 and 10', are transformed into spherical waves emanating from the first focus of the second-order surface towards additional parts 9 and 9' of reflector 1.

Taking into account that the focal axes of the paraboloid forming the additional parts 9 and 9' of the reflector 1 lie in the same plane with the focal axes of the additional parts 10 and 10' of the counter-reflector 2, and the focus of the paraboloid for each of the additional parts 9 and 9' of the reflector 1 coincides with the first focus of the corresponding additional parts 10 and 10' of the counter-reflector 2, the waves, reflected from the additional parts 9 and 9' of the reflector 1, are transformed into plane waves without phase errors, forming highly directional radiation of partial rays of the antenna with maxima directed along the axes 6' and 6''.

Thus, the radiation of the outer feeds 12 and 13, which in a conventional two-mirror toroidal-parabolic antenna partially passes by the counter-reflector 2, is now reflected by its additional parts 10 and 10' and then by additional parts 9 and 9' of the reflector 1. Thanks to this, an increase in the transmission coefficient is achieved energy from the feed to the antenna counter-reflector for the corresponding beams. Due to the absence of phase errors after the reflection of waves from additional parts 10 and 10', 9 and 9', an increase in the aperture instrumentation of the opening is achieved. Since the generalized KIP (efficiency) of the partial beam of a two-mirror antenna is proportional to the product of the aperture KIP of the opening and the energy transfer coefficient from the feed to the counter-reflector [2, 4], then for the outer feeds 12 and 13 the declared technical result is achieved, that is, an increase in the efficiency of partial beams compared to a conventional two-mirror toroidal-parabolic antenna.

LITERATURE

1. Frolov O.P., Wald V.P. Mirror antennas for satellite earth stations. - M.: Hotline-Telecom, 2008. - 496 p.: ill.

2. Somov A.M., Kabetov R.V. Design of antenna-feeder devices: Textbook for universities. / Ed. Professor A.M. Somova. - M.: Hotline - Telecom, 2015. - 500 pp.: ill.

3. Somov A.M. Fragmentation method for calculating the noise temperature of antennas. - M.: Hotline - Telecom, 2008. - 208 p.: ill.

4. Aizenberg G.Z., Yampolsky V.G., Tereshin O.N. VHF antennas. / Ed. G.Z. Eisenberg: In 2 parts. Part 2. - M., Svyaz, 1977. - 288 pp.: ill.

Claims (1)

A composite multi-beam two-mirror antenna consisting of a reflector - the main mirror - and a counter-reflector - an auxiliary mirror - in the form of conducting surfaces, as well as a system of irradiators facing the counter-reflector located on a circular arc, characterized in that the reflector and counter-reflector, each, consist of three corresponding parts to each other: the central part and two additional parts adjacent to it, and the shape of the surface of the central part of the reflector is formed by the rotation of a symmetrical section of a parabola, the focus of which lies in the plane of location of the irradiators, around an axis perpendicular to the focal axis of the parabola and passing through the center of the circle of the irradiators arc, the shape the surface of the central part of the counter-reflector is formed by rotating a section of a second-order curve that is symmetrical relative to the focal axis around an axis perpendicular to the focal axis of this curve and coinciding with the axis of rotation of the parabola of the central part of the reflector; the surfaces of the additional parts of the reflector are symmetrical halves of a paraboloid obtained by rotating a section of the parabola identical to the section, forming the central part of the reflector, around the focal axis of a given parabola, the surfaces of the additional parts of the counter-reflector are symmetrical halves of a second-order surface obtained by rotating a section of the second-order curve, identical to the section forming the central part of the counter-reflector, around the focal axis of this curve, the focal axes of the additional and central parts lie in the same plane, the first foci of the second-order curves forming the central and additional parts of the counter-reflector coincide with the foci of the parabolas, forming the central and additional parts of the reflector, respectively, and the second foci of the second-order curves forming the central and additional parts of the counter-reflector lie on the arc of the location of the irradiators .