RU2776725C1 - Multibeam multiband multireflector antenna - Google Patents

Abstract

FIELD: antenna technology.

SUBSTANCE: invention relates to antennas of the Earth stations of satellite communication systems. The result is achieved by the fact that the antenna, consisting of systems of irradiators located on three concentric arcs of circles lying in the transverse plane, the main reflector having the shape of a parabola in the longitudinal plane, orthogonal plane of arcs, an auxiliary subdish and an additional reflector and subdish coaxial with them, symmetrical with respect to the focal axis of the parabola, the cross-sections of which in the transverse plane are circles concentric to the arcs of the irradiators, differs in that the cross-section of the subdish in the longitudinal plane has the form of a parabola, concave away from the reflector, its focal axis and focus are aligned with the focal axis and the focus of the reflector, an additional reflector with a cross-section similar to the section of the reflector, and an additional subdish with a cross-section in the form of an ellipse concave towards the counter-reflector, are installed so that their focal axes coincide with the focal axis of the reflector, and the longitudinal size of the additional reflector coincides with the same size of the subdish, and the focus is combined with the one closest to the additional subdish to the focus of the ellipse.

EFFECT: increase in the efficiency of the antenna while simultaneously receiving radio waves of three frequency ranges.

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Description

The field of technology to which the invention belongs

At present, artificial Earth satellites (AES) are widely used for radio communications and digital broadcasting - repeaters located in geostationary orbit (GSO) and simultaneously using the C, Ku and Ka frequency bands. In the future, it is planned to use frequency bands of 40 GHz and more [1].

The present invention relates to the field of radio engineering and is intended for use as earth station antennas of satellite communication systems with repeaters of the microwave-EHF ranges located on the GSO for simultaneous operation with several communication satellites, each of which operates simultaneously in three frequency bands.

State of the art

Symmetrical two-mirror toroidal-parabolic antennas of the Cassegrain type [2] and similar [3] are known, consisting of a parabolic mirror - a reflector in the form of a symmetrical cutout from a parabolic torus, an auxiliary mirror - a counter-reflector in the form of a symmetrical cutout from an elliptical or hyperbolic torus, coaxial to the reflector, and irradiators. In this case, the focus of the reflector parabola and the focus of the counterreflector combined with it, when rotating about an axis orthogonal to the focal one, describe a circular arc similar to the arc passing through the second focus of the parabola. Feeders are placed on the arc of the second foci, creating a multi-beam fan of radiation patterns. Such antennas make it possible to organize radio communication through several satellites on the GSO simultaneously in several frequency bands using frequency band separation devices [4, 5]. The disadvantages of such an antenna include its reduced efficiency when receiving several bands at the same time on one feed, due to the loss of electromagnetic energy in the device for separating frequency bands.

There are also known multi-beam band mirror antennas [6, 7], which allow simultaneous reception of two frequency bands without the use of a band separation device. However, such antennas do not allow simultaneous operation in three frequency bands with each of the GSO satellites.

Disclosure of the essence of the invention

The technical result of the invention is to increase the efficiency of the antenna while maintaining the fan-shaped radiation patterns and the simultaneous reception of three frequency bands from each direction. For this purpose, a multi-beam multi-band multi-mirror antenna is proposed, consisting of feed systems located on three concentric circular arcs lying in the same transverse plane, the main reflector mirror having circular arcs in the longitudinal plane, orthogonal to the plane, the shape of a parabola, an auxiliary counter-reflector mirror and coaxial with them additional mirrors-reflectors and mirrors-counter-reflectors, symmetrical about the focal axis of the parabola. Cross-sections of the additional mirror-reflector and the mirror-counter-reflector in the transverse plane are circles concentric to the arcs of the irradiators and having a larger and smaller radius relative to each other, respectively. The first arc of the irradiators passes through the focus of the parabola forming the reflector and contains the irradiators of the first frequency range. The cross-section of the counter-reflector in the longitudinal plane has the form of a parabola, concave away from the reflector, the focal axis and focus of which are aligned, respectively, with the focal axis and focus of the parabola forming the reflector. An additional reflector with a cross section similar to that of the reflector and an additional counter-reflector with a cross-section in the form of an ellipse concave towards the counter-reflector are installed so that their focal axes coincide with the focal axis of the parabola forming the reflector. In this case, the longitudinal size of the additional reflector coincides with the same size of the counter-reflector, and the focus is aligned with the focus of the ellipse closest to the additional counter-reflector. On the arc passing through this focus, feeders of the second frequency range are installed. The irradiators of the third frequency range are mounted on an arc passing through the far focus of the ellipse.

Brief description of the drawings

The invention is illustrated by drawings, in which:

- fig. 1 - longitudinal section of a multi-beam multi-band multi-mirror antenna;

- fig. 2 is a cross section of a multi-beam multi-band multi-mirror antenna.

The drawings indicate:

1 - reflector;

2 - counter-reflector;

3 - irradiator of the first frequency range;

4 - additional reflector;

5 - additional counter-reflector;

6 - irradiator of the second frequency range;

7 - irradiator of the third frequency range;

8 - direction of the axis of symmetry of the longitudinal section of the antenna;

9 - the direction of the rays to the edges of the reflector from the irradiators of the first, second and third frequency ranges;

10 - direction of radiation of the antenna from feeds 3, 6 and 7;

11 - the direction of the rays to the edges of the additional reflector from the irradiators 6 and 7;

12 - direction of radiation of the additional reflector to the counter-reflector;

13 - the direction of the rays of the irradiators 6 and 7 from the edges of the counter-reflector 2 to the edges of the reflector;

14 - the direction of the rays of the irradiator 7 and the additional counter-reflector to the edges of the additional reflector;

15 - arc placement of feeders of the first frequency range;

16 - arc placement of irradiators of the second frequency range;

17 - arc placement of irradiators of the third frequency range;

18 - multi-beam multi-range fan of radiation patterns.

Implementation of the invention

A multi-beam multi-band multi-mirror antenna with a coaxial reflector 1 and a counter-reflector 2 in the form of parabolic tori, as well as an additional reflector 4 in the form of a parabolic torus and an additional counter-reflector 5 in the form of an elliptical torus (according to the Gregory scheme) with the same focal axes of the generatrix of the parabola and the ellipse 8 contain feed 3 the first frequency range (Fig. 1) and the like, located in the coinciding foci of the parabolas 1 and 2, forming an arc of a circle of feeds of the first frequency range 15.

When connected to the irradiator 3 and similar generator of the first frequency range, the irradiator 3 emits a spherical wave, including towards the upper and lower edges of the reflector 1. Since the reflector is usually located in the far radiation zone relative to the irradiator, this wave can be considered in the form of rays 9 After reflection from the reflector 1, these rays, since they come from the focus of the parabola, form in the transmission mode (and according to the principle of reciprocity and in the reception mode) directed radiation 10 along the focal axis 8.

When the generator of the second frequency range is connected to the irradiator 6 and the like, located on the arc of the irradiators 16, passing through the foci of the additional counter-reflector 5 and the additional reflector 4, this irradiator emits a spherical wave in the direction of the reflector 4. After reflection from the reflector 4, the beams 11, since they come from the focus of the parabola, become parallel to the focal axis 8, thus forming a plane wave. Beams 12, corresponding to a plane wave, reach counterreflector 2 and, being reflected from its parabolic surface, after crossing beams 13 at coincident foci of surfaces 1 and 2, it enters from focus 2 in the form of a diverging spherical wave to surface 1, forming directed radiation 10 along the focal axis 8 second frequency range.

The generator of the third frequency range is connected to the irradiator 7 and the like, located on the arc of the irradiators 17, passing through the focus of the additional elliptical counter-reflector 5, remote from the top of the additional parabolic reflector 4 and coinciding with its focus. According to the properties of the ellipse 5, the distances from the focus of the irradiator 7 to any point of the ellipse and further to the second focus of the ellipse, which coincides with the focus of the additional reflector 4, are equal. Therefore, the rays 14 emanating from the irradiator 7 seem to come from the second focus of the ellipse and, thus, when reflected from 4, they form a plane wave with rays 12. The plane wave of the third frequency range reaches the parabolic counter-reflector 2, after being reflected from it and passing the spherical wave through its focus falls on reflector 1. As a result of the reflection of this wave by reflector 1, directed radiation of the third frequency range is formed in the antenna aperture along axis 8.

At the same time, in the transverse plane (Fig. 2) feeds 3, 6 and 7 form a multi-beam multi-band fan of partial radiation patterns (DN) of the antenna, each directed to its own satellite. The feeds of the first frequency range 3, the feeds of the second frequency range feeds 6 and the feeds of the third frequency range 7 can lie on the radii common to the arcs of circles 15, 16 and 17. In this case, the rays of the fan of the partial antenna pattern from all feeds coincide in direction.

In the transverse plane, the irradiators of the first frequency range are located at half the radius of the arc of the reflector 1, equal to twice the focal length of the parabola 1.

Irradiators 3, 6 and 7 have a shading effect on each other's radiation. At the same time, according to the geometric constructions of the beam path, the shading effect of the irradiator 7, which it has on the radiation of the irradiator 6, does not exceed the shading from the additional counter-reflector 5. The shading effect of the irradiators 3 and 6 can be minimized with an appropriate distribution of frequency ranges over the irradiators. If the first band corresponds to the highest frequencies (for example, Ka band), the second band - to medium frequencies (Ku band), the third band - to low frequencies (C band), then the dimensions of the irradiator 3 will be much smaller than the wavelengths relative to the second and third bands, and the dimensions of the irradiator 6 are much smaller than the wavelength of the third range. In this case, the impact of the irradiators 3 and 6 on the electromagnetic waves passing by them will be small.

For simultaneous operation in several frequency ranges, known antennas use feeds that are common to several frequency ranges in conjunction with band separation devices that introduce additional high-frequency losses, reduce the utilization factor and increase the noise temperature of the antenna. In the proposed antenna, the separation of frequency bands is carried out by the method of spatial division of the reception into several feeds 3, 6 and 7, which increases the efficiency of the antenna.

LITERATURE

1. Spodobaev M.Yu. Key challenges and main trends in the development of the satellite communications industry in the medium term. / SATCOMRUS 2017, November 1, 2017

2. Somov A.M., Kabetov R.V. Multibeam reflector antennas: geometry and methods of analysis. - M.: Hotline-Telecom, 2019. - 384 p.: ill.

3. Mirror antenna: Patent RU 2173496: IPC H01Q 19/19. / V.A. Kaloshin; Application 200117951/09 dated July 10, 2000; Published September 10, 2001

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

Fig. 5. Cascade of a microwave receiver with frequency separation of orthogonal polarizations of two frequency bands: Patent RU 2136088: IPC H01R 1/161, H04V 1/00. / A.M. Somov, A.V. Pugachev; Application RU 98105930 dated March 17, 1998; Published 08/27/1999

6. Multibeam range reflector antenna: Patent RU 2620875: IPC H01Q 19/19. / A.M. Somov; Application RU 2016129028 dated July 15, 2016; Published May 30, 2017

7. Non-tilted multibeam band two-mirror antenna: Patent RU 2664870: IPC H01Q 5/00. / M.A. Somov, K.M. Volgatkin, A.M. Somov; Application RU 2017140173 dated November 20, 2017; Published 08/23/2018

Claims (1)

A multi-beam multi-band multi-mirror antenna, consisting of feed systems located on three concentric arcs of circles lying in the same transverse plane, the main reflector mirror having in the longitudinal plane, orthogonal to the plane of arcs of circles, the shape of a parabola, an auxiliary mirror-counter-reflector and coaxial with them additional mirror-reflector and mirror-counter-reflector, symmetrical about the focal axis of the parabola, the sections of which in the transverse plane are circles concentric to the arcs of the irradiators and having relative to each other a larger and smaller radius, respectively, characterized in that the first arc of the irradiators passes through the focus of the parabola forming reflector, and contains irradiators of the first frequency range, the cross-section of the counter-reflector in the longitudinal plane has the form of a parabola concave away from the reflector, the focal axis and focus of which are aligned, respectively, with the focal axis and focus of the parabola forming the reflector reflector, an additional reflector with a cross section similar to the reflector section, and an additional counter-reflector with a cross-section in the form of an ellipse concave towards the counter-reflector are installed so that their focal axes coincide with the focal axis of the parabola forming the reflector, and the longitudinal dimension of the additional reflector coincides with the same the size of the counter-reflector, and the focus is aligned with the focus of the ellipse closest to the additional counter-reflector, on the arc passing through this focus, the irradiators of the second frequency range are installed, and the irradiators of the third frequency range are installed on the arc passing through the far focus of the ellipse.

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