JPH0680972B2 - Reflector antenna - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reflector antenna mounted on a geostationary satellite and forming a shaped beam that efficiently irradiates a predetermined service area.

[Prior Art] A conventional reflector antenna is disclosed, for example, in Japanese Examined Patent Publication No. 50-15341. As shown in FIGS. 10 and 11, the reflector antenna 1 is a reflector 1 in which the shape of the central portion 1a is a revolving hyperboloid and the shape of the peripheral portion 1b is a curved surface including a parabola in a specific direction, as shown in FIGS. And a primary radiator 3 which is composed of one horn 2 which radiates a spherical wave and which is substantially at the focal position of the reflecting mirror 1. The reflector 1 is fixed to the satellite body 5 via a support 4. Then, the spherical wave radiated from the horn 2 of the primary radiator 3 is reflected by the reflecting mirror 1, and the equiphase surface of the radio wave becomes a part of the spherical wave in the central portion A as shown in FIGS. In the peripheral part B, one of the shaded curved waves obtained by accumulating the intersection E of the tangent plane of the spherical wave at each point D on the boundary curve C with the central part A and the plane perpendicular to the boundary curve C. It becomes a part.

Therefore, by matching the shape of the boundary curve with the shape of the service area on the earth as viewed from the satellite body, the cross-sectional shape of the beam can be matched with the service area, and the service area can be efficiently irradiated.

[Problems to be Solved by the Invention] When using the above-mentioned mirror antenna having a mirror-finished offset shape with linear polarization, the mirror 1 is non-rotationally symmetric about the main beam direction of the radiation pattern as an axis. , And since the reflecting mirror 1 is mirror-finished, a cross polarization component is generated by the reflecting mirror 1, and the cross polarization level of the radiation pattern becomes high. Therefore, when two orthogonal linearly polarized waves are used, there is a problem that a radio wave excited by one polarization interferes with a radio wave excited by the other polarization.

The present invention has been made to solve the above problems,
An object of the present invention is to obtain a reflector antenna in which interference between two orthogonal polarizations that are orthogonal to each other is reduced by lowering the cross polarization level of the radiation pattern and forming a shaped beam that efficiently irradiates a predetermined service area. To do.

[Means for Solving the Problems] In order to achieve the above object, the reflector antenna of the present invention has a primary radiator that includes a first horn and a second horn and radiates two orthogonal linearly polarized waves. The radiation mirror has a double structure of a first reflecting surface and a second reflecting surface, and the central portion of both the first and second reflecting surfaces is formed into a rotating hyperboloid, and the periphery of the reflecting surface is the same. By forming the part into a curved surface including a parabola in a specific direction, the reflector is configured so that the beam composed of the main polarization component of the linearly polarized light emitted from the primary radiator irradiates a predetermined service area efficiently. The first and second reflecting surfaces are mirror-finished and each of the first and second reflecting surfaces is composed of a large number of linear conductors and a dielectric material that supports these conductors. The conductors of the first reflecting surface are projected. The lines are parallel to each other, and the line projecting the conductor of the second reflection surface is the first reflection surface. Of the linearly polarized light radiated from the second horn while reflecting the main polarized wave component of the linearly polarized light radiated from the first horn by being orthogonal to the projected line of The main polarization component of the wave is passed, and the multiple conductors on the second reflection surface reflect the main polarization component of the linear polarization emitted from the second horn.

Further, when the number of the primary radiator is one, the reflecting mirror is arranged so that the beam composed of the main polarization component of the linearly polarized wave emitted from the one primary radiator efficiently irradiates a predetermined service area. Is mirror-finished.

Further, when there are a plurality of primary radiators, each beam composed of the main polarization component of the linearly polarized wave radiated from each of the plurality of primary radiators is used to efficiently irradiate a predetermined service area with each beam. The reflecting mirror is mirror-finished so that the level in the intersecting direction of is a predetermined level.

[Operation] When a radio wave composed of two linearly polarized waves orthogonal to each other is radiated from the primary radiator, the reflector antenna of the present invention is the main of the linearly polarized wave radiated from the first horn among the radio waves. While the polarized component is reflected by many conductors in the first reflecting surface, the main polarized component of the linearly polarized wave emitted from the second horn passes between many conductors in the first reflecting surface. And is reflected by many conductors in the second reflecting surface. When the main polarization components of the two linearly polarized waves orthogonal to each other are reflected by both the first and second reflecting surfaces, the rotating hyperboloid in the central portion of the both reflecting surfaces and the specific direction of the peripheral portion of the both reflecting surfaces. Is reflected by a curved surface including a parabola.
That is, a radio wave composed of two linearly polarized waves orthogonal to each other radiated from the primary radiator emits a large number of conductors in the first reflecting surface and the second conductor.
Separation is caused by a deflecting action due to a synergistic action with a large number of conductors in the reflecting surface. Then, when the separated radio waves are reflected by a large number of conductors in both the first and second reflecting surfaces, the shape effect of the rotating hyperboloid at the central portion of both the first and second reflecting surfaces. The radio wave equiphase surface becomes a part of the spherical wave in the central part, and the radio wave isophase surface is surrounded by the shape effect of the spherical surface including the parabola in the specific direction around the first and second reflecting surfaces. In the part, it becomes a part of the shaded spherical wave obtained by accumulating the intersection line of the tangent plane of the spherical wave at each point on the boundary line with the central part and the plane perpendicular to the boundary line. As a result, the beam having the desired beam cross-sectional shape with a small cross-polarization component is first
It is formed by two main polarized waves reflected by both the reflection surfaces of the first and second reflection surfaces.

Therefore, when there is only one primary radiator, the reflecting mirror having the above-mentioned first and second reflecting surfaces and having the boundary modified is, for example, the Japanese Islands with a relatively large area or the Kanto area with a smaller area. It is possible to efficiently cover a predetermined service area such as a rural area.

Further, when there are a plurality of primary radiators, the reflecting mirror having the first and second reflecting surfaces and having a mirror-finished surface is used for linearly polarized waves radiated from each of the plurality of primary radiators. By setting the level in the cross direction of each beam composed of the main polarization component to a predetermined level, a predetermined service area such as the relatively large area of the Japanese archipelago or the smaller area of the Kanto region can be isolated. At the same time or independently independently.

Embodiments Embodiments of the present invention will be described in detail below with reference to FIGS.

Example 1 (corresponding to claim 1 and claim 2). 1 is a side view showing the structure of a reflector antenna as a first embodiment of the present invention, FIG. 2 is a front view showing the structure of a reflector antenna of the first embodiment, and FIG. FIG. 4 is a front view of the first reflecting surface of the reflecting mirror antenna, FIG. 4 is a front view of the second reflecting surface of the reflecting mirror antenna of the first embodiment, and FIG. 5 is a radiation pattern of the reflecting mirror antenna of the first embodiment. It is an explanatory view shown.

In FIGS. 1 and 2, reference numeral 6 denotes a reflecting mirror, which is configured by arranging a first reflecting surface 7 and a second reflecting surface 8 in double. Reference numeral 9 denotes a primary radiator, which includes a first horn 10 that radiates one linearly polarized wave and a second horn 10 that radiates the other linearly polarized wave orthogonal to the linearly polarized wave radiated from the first horn 10. It has a horn 11. 12 is a satellite body 13 and a reflector 6
Is a support for fixing.

The central portion 7a of the first reflecting surface 7 and the central portion 8a of the second reflecting surface 8
Is formed in the shape of a rotating hyperboloid, and is a peripheral portion of the first reflecting surface 7.
7b and the peripheral portion 8b of the second reflecting surface 8 are formed in the shape of a curved surface including a parabola in a specific direction. In addition, the first reflecting surface 7
Is composed of a large number of linear conductors 14 and a dielectric 16 that supports these conductors 14, as shown in FIG.
Is composed of a large number of linear conductors 15 and a dielectric 17 that supports these conductors 15, as shown in FIG.
The projection lines of the conductors 14 provided on the second reflection surface 8 are parallel to each other, and the projection lines of the conductors 15 provided on the second reflecting surface 8 are orthogonal to the projection lines of the conductors 14. It is configured.

In the reflector antenna of the first embodiment, the primary radiator 9
When the first horn 10 is excited by a linearly polarized wave which is perpendicular to the paper surface of FIG. 1, and the second horn 11 is excited by a linearly polarized wave which is parallel to the paper surface, the main polarization of the radio wave radiated from the first horn 10 is Since the wave direction coincides with the direction of the linear conductor 14 that forms the first reflecting surface 7 shown in FIG. 3, the radio waves emitted from the first horn 10 are mainly reflected by the first reflecting surface 7. The electric wave of the cross polarization component in the direction orthogonal to the parallel direction of the conductor 14 passes through the first reflecting surface 7, and the electric wave of the cross polarization component is located at the second reflecting surface after the first reflecting surface 7. It is reflected by the conductor 15 that forms part 8. Since the second reflecting surface 8 is arranged so that the beam travels in a desired direction when excited by the second horn 11 of the primary radiator 9, the cross polarization emitted from the first horn 10 is obtained. Radio waves of wave components are radiated in directions other than the desired direction of the first reflecting surface 7. As a result, only the radio wave of the main polarization component radiated from the first horn 10 is reflected by the first reflecting surface 7 and shaped into a desired wavefront shape. Similarly, only the main polarization component of the radio wave radiated from the second horn 11 of the primary radiator 9 passes through the first reflecting surface 7 and is reflected by the second reflecting surface 8 to be shaped into a desired wavefront shape. It Therefore, the first and second reflecting surfaces
Both main polarizations reflected at 7 and 8 have desired beam cross-sectional shapes with small cross polarization components.

Next, an application example of the reflector antenna of the first embodiment will be described with reference to FIG. In FIG. 5, 18 is the Japanese Islands seen from a point on the geostationary orbit, and 19 is a shaped beam having a sectional shape shown by contour lines at 2 dB intervals. That is, when the first horn 10 is excited by a linearly polarized wave which is perpendicular to the plane of FIG.
Since only the radio wave of the linear polarization component perpendicular to the paper surface of FIG. 1 which is the main polarization is reflected by the first reflecting surface 7 to form the shaped beam 19 having a desired wavefront shape with a small cross polarization component,
The shaped beam 19 can efficiently cover the Japanese archipelago 18 efficiently as shown in FIG. Also, the second horn 11 is the first
Even when excited by a linearly polarized wave parallel to the plane of the figure, only the radio wave of the linearly polarized component parallel to the plane of the plane of FIG. Since the shaped beam 19 having a desired small wavefront shape is shaped, the shaped beam 19 can efficiently cover the Japanese archipelago 18 efficiently as shown in FIG.

Example 2 (corresponding to claim 1 and claim 3). 6 is a side view showing the configuration of a reflector antenna as a second embodiment of the present invention, FIG. 7 is a front view showing the configuration of a reflector antenna of the second embodiment, and FIG. 8 is a view of the second embodiment. FIG. 9 is an explanatory view showing a radiation pattern formed by main polarized waves individually radiated from a plurality of primary radiators, and FIG. 9 shows a feed system for simultaneously forming the shaped beam and the beam of Example 2 independently and simultaneously. It is a circuit diagram shown.

In FIGS. 6 and 7, the case where three primary radiators 9a, 9b and 9c are installed is shown as an example. One primary radiator 9a comprises a first horn 10a and a second horn 11a, another primary radiator 9b comprises a first horn 10b and a second horn 11b, and the remaining one primary radiator 9c First horn 10c and second horn 1
Equipped with 1c. Further, the reflecting mirror 6, the first reflecting surface 7, the central portion 7a, the peripheral portion 7b, the second reflecting surface 8, the central portion 8a, the peripheral portion 8
b, the support 12 and the satellite body 13 are similar to those in FIGS. 1 and 2 and have similar functions.

Next, an application example of the reflector antenna of the second embodiment
This will be described with reference to the drawings and FIG. In FIG. 8, 10A is a beam having a sectional shape shown by contour lines at 2 dB intervals when the first horn 10a or the second horn 11a is individually excited, and 10B is the first horn 10b or the second horn 11.
The beam with the cross-sectional shape shown by the contour line at 2 dB intervals when b is individually excited, and the beam with the cross-sectional shape shown by the contour lines at 2 dB intervals when the first horn 10c or the second horn 11c is individually excited. is there. In the second embodiment, each of the beams 10A to 10C has an elliptical shape.
The first reflecting surface 7 and the second reflecting surface 8 are mirror-finished so that the level in the crossing direction between the beam 10B and the beam 10B and the level in the crossing direction between the beam 10B and the beam 10C are about −6 dB, respectively. .

Therefore, in the second embodiment, when the first horns 10a, 10b, and 10c are simultaneously excited by linearly polarized waves perpendicular to the paper surface of FIG. Only the beam is reflected by the first reflecting surface 7, each of the beams 10A, 10B and 10C has an elliptical shape and the level in the beam crossing direction is about −6d.
Since it becomes B, a shaped beam 19 having a desired wavefront shape with a small cross polarization component is formed as shown in FIG. 5, and this shaped beam 19 can efficiently cover the Japanese Islands 18 without waste. Similarly, in the second embodiment, the second horns 11a, 11b,
When each of 11c is excited by linearly polarized waves parallel to the paper surface of FIG. 6, a shaped beam 19 having a desired wavefront shape with a small cross polarization component is formed as shown in FIG. The Japanese archipelago 18 can be covered efficiently without waste.

Further, in the second embodiment, in addition to the shaped beam 19 that covers the entire Japanese archipelago 18, for example, the beam 10B that irradiates the Kanto region where communication demand is high can be formed simultaneously and independently of the shaped beam 19. . An example of a power supply system for forming the shaped beam 19 that covers the entire Japanese archipelago 18 and the beam 10B that covers the Kanto region, which is much smaller in area than the Japanese archipelago 18, will be described with reference to FIG. Different frequencies are used for the shaped beam 19 and the beam 10B. In FIG. 9, 21a and 21b are beam forming circuits, 22a and 22b are demultiplexers, 23a and 23b are shaped beam terminals for forming a shaped beam 19, and 24a and 24b are for forming a beam 10B. This is the terminal for the beam. The first horns 10a, 10b, 10c and the second horns 11a, 11b, 11c are similar to those in FIGS. 6 and 7 and have similar functions. Molded beam terminal 23
The radio waves input to the a or shaped beam terminal 23b are distributed by the beam forming circuits 21a and 21b to the first horns 10a, 10b and 10c or the second horns 11a, 11b and 11c with desired amplitude and phase. The shaped beam 19 is formed. On the other hand, beam terminal
Radio waves having a frequency different from the frequency of the shaped beam 19 incident on the first horn 10b pass through the demultiplexers 22a and 22b.
Alternatively, the second horn 11b is excited to form the beam 10B.
The demultiplexers 22a and 22b separate the radio wave of the shaped beam 19 and the radio wave of the beam 10B having different frequencies. As a result, the shaped beam 19 that covers the Japanese archipelago 18 shown in FIG. 5 and the beam 10B that covers the Kanto region where communication demand is high as shown in FIG. 8 can be formed independently at the same time. Therefore, according to the second embodiment, there is also an advantage that it is possible to configure a reflector antenna that can flexibly cope with a change in communication demand.

In the second embodiment, three horns are excited by each linearly polarized wave, but the number may be different depending on the service area and method.

The shape of the central portion and the shape of the peripheral portion of the reflecting surface determine the desired wavefront, and as shown in FIG. 14, a point M on the reflecting mirror G, a point M and a wavefront (equal phase surface) H are formed. It is determined based on the principle that the total length of the lines connecting the upper points R is constant and the optical path length is constant.

Although the case where the antenna is used as an antenna for mounting a geostationary satellite has been described above, the reflector antenna of the present invention can be applied as an antenna for terrestrial communication.

[Effects of the Invention] In the reflector antenna of the present invention, a radio wave composed of two linearly polarized waves orthogonal to each other and radiated from the primary radiator is generated by a conductor in the first reflecting surface and a conductor in the second reflecting surface. It is separated by the two deflection actions, and the separated radio wave
When reflected by the conductors in both the reflecting surfaces of
Due to the two geometrical effects of the rotating hyperboloids in the central portions of both the reflecting surfaces of the first and second reflecting surfaces, the equiphase surface of the radio wave becomes a part of the spherical wave in the central portion, and the peripheral portions of the first and second reflecting surfaces Due to the two geometrical effects of the curved surface including the parabola in the specific direction, the tangential plane of the spherical wave and the plane perpendicular to the boundary line at the points where the equiphase surface of the radio wave is at the peripheral part in the peripheral part By making it a part of the shaded curved wave obtained by integrating the lines, the two main polarizations reflected by both the first and second reflecting surfaces are desired to have a small cross polarization component. It is possible to form a beam having a beam cross-sectional shape of

Therefore, when there is only one primary radiator, a reflector having both the first and second reflecting surfaces and having a mirror-finished surface is, for example, the Japanese Islands with a relatively large area or the Kanto area with a smaller area. There is an effect that a predetermined service area such as a rural area can be efficiently covered.

Further, when there are a plurality of primary radiators, the reflecting mirror having the first and second reflecting surfaces and having a mirror-finished surface is used for linearly polarized waves radiated from each of the plurality of primary radiators. By setting the level in the cross direction of each beam composed of the main polarization component to a predetermined level, a predetermined service area such as the relatively large area of the Japanese archipelago or the smaller area of the Kanto region can be isolated. There is an effect that they can be efficiently covered simultaneously at the same time or independently.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of a reflector antenna in the first embodiment of the present invention, FIG. 2 is a front view of the reflector antenna in the first embodiment, and FIG. 3 is a first reflection in the reflector in the first embodiment. Front view of the surface, FIG. 4 is a front view of the second reflecting surface of the reflecting mirror of the first embodiment, FIG. 5 is an illustration of the radiation pattern by the reflecting mirror antenna of the first embodiment, and FIG. Example 2
FIG. 7 is a side view showing the configuration of the reflector antenna in FIG. 7, FIG. 7 is a front view of the reflector antenna of Embodiment 2, and FIG.
FIG. 9 is an explanatory view showing an example of a radiation pattern by a reflector antenna of FIG. 9, FIG. 9 is a circuit diagram showing a configuration of a power feeding system for independently forming a shaped beam and a beam of Embodiment 2, and FIG. FIG. 11 is a side view showing the configuration of a mirror antenna, FIG. 11 is a front view of a conventional reflecting mirror antenna, FIG. 12 is a front view showing the shape of an equiphase surface of a radio wave reflected from a conventional reflecting mirror, and FIG. FIG. 12 is a side view of the equiphase surface shape shown in FIG. 12, and FIG. 14 is an explanatory view of the principle of constant optical path distance connecting the focal point to the reflection surface and the equiphase surface in the reflector antenna. 6 ... Reflecting mirror, 7 ... First reflecting surface, 7a ... Central part of first reflecting surface, 7b ... Peripheral part of first reflecting surface, 8 ... Second reflecting surface, 8a ... Second reflecting surface Center part of the surface, 8b ...... Peripheral part of the second reflecting surface, 9,9a9b, 9c …… Primary radiator, 10,10a, 10b, 10c ……
The first horn of the primary radiator, 10A, 10B, 10C ... Beam, 11,
11a, 11b, 11c ... second horn of primary radiator, 14 ... first
Reflective surface conductor, 15 ... Second reflective surface conductor, 16 ... First reflective surface dielectric, 17 ... Second reflective surface dielectric, 18 ...
Japanese archipelago, 19 ... Molded beam.

Claims (3)

[Claims] 1. A reflector antenna comprising a reflector and a primary radiator installed substantially at the focal point of the reflector, wherein the primary radiator radiates a linearly polarized wave, and the linear horn. A second horn that radiates a linearly polarized wave that is orthogonal to the polarized wave, wherein the reflecting mirror has a shape in which a central portion is formed into a rotating hyperboloid and a peripheral portion is formed into a curved surface including a parabola in a specific direction. By arranging the reflecting surface and the second reflecting surface having a shape in which the central portion is formed into a hyperboloid of revolution and the peripheral portion is formed into a curved surface including a parabola in a specific direction, the primary radiator is radiated. The beam composed of the main polarization component of the linearly polarized wave is mirror-modified to efficiently irradiate a predetermined service area, and each of the first reflection surface and the second reflection surface has a large number of lines. The conductors and the conductors The main body of the linearly polarized wave emitted from the second horn reflects the main polarized wave component of the linearly polarized wave radiated from the first horn, and The lines projecting the conductors of the first reflecting surface are parallel to each other so as to pass the polarized component, and the multiple conductors of the second reflecting surface are the main components of the linearly polarized wave radiated from the second horn. The line projecting the conductor of the second reflective surface is the conductor of the first reflective surface so as to reflect the polarized component and pass the main polarized component of the linearly polarized wave radiated from the first horn. A reflector antenna characterized by being orthogonal to the projected line. 2. The reflector antenna according to claim 1, wherein one primary radiator is installed. 3. A plurality of the above-mentioned primary radiators are installed, while a reflecting mirror comprising the above-mentioned first reflecting surface and a second reflecting surface is a main polarized wave of linearly polarized light radiated from each of the plurality of primary radiators. The reflector antenna according to claim 1, wherein the level of each component beam in the intersecting direction is mirror-finished so as to reach a predetermined level in order to efficiently irradiate a predetermined service area. .