JPS5816801B2 - microwave antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small-sized co-frequency sharing (multiple use) antenna device, and more particularly to an antenna device that shares a frequency using a signal source and a reflector that are polarized at right angles to each other.

As the demand for the use of more frequency bands (spectrum) increases, it becomes absolutely necessary to make more sophisticated use of the allocated frequencies.

In the case of satellite communications where the target area covers most of the earth's surface, the above-mentioned high-level utilization is especially necessary.

Also, from the point of view of economy, it is preferable to increase the number of channels per frequency band.

Frequency band sharing is actually achieved by transmitting waves polarized at right angles to each other.

Separation of two orthogonally polarized waves can be achieved by placing a large distance between the feeder transmitting the orthogonally polarized waves and the reflector coupled thereto.

However, especially in satellite communication antenna systems, although it is preferable to share a frequency band, it is necessary to further miniaturize the antenna system.

In the case of a satellite-mounted antenna, miniaturization is especially necessary.

Considering the above-mentioned conditions, there is one problem in realizing a compact frequency-sharing antenna, namely, how to eliminate the influence of undesired interference polarization.

This invention aims to solve this problem.

The invention provides orthogonally polarized first and second beams forming a beam.
The present invention relates to a microwave antenna device including first and second power feeding means for transmitting waves.

and the device further comprises two grating devices which are offset from each other such that the parallel reflector elements of one are at right angles to the parallel reflector elements of the other. They are screwed together and installed in combination.

Further, one of the grating devices includes the first power feeding means (for example, a focal point r, to be described later) disposed at a focal point (for example, a focal point r, to be described later) of the first wave and a first reflector (for example, a reflector 12, which will be described later). The flange constitutes the surface of a first parabolic reflector that cooperates with the horn 19a) described below, and said other grating device serves as a surface for said second wave and a second reflector (e.g. A second power feeding means (for example, a horn 19b, which will be described later) disposed at a focal point (for example, a focal point f2, which will be described later) of a reflector 13 (which will be described later).
constitutes the surface of a parabolic reflector.

Further, in the vicinity of the focal point of the first reflector, an interference polarization signal (for example, wave 2 described later) generated by each of the grating devices is detected.
6h.

36v) is the direction of the beam (for example, direction 28 described below)
The surface of the second parabolic reflector is such that the focus of the second reflector is located a sufficient distance away from the focus of the first reflector to deviate from the focus of the second reflector. Disposed offset from the surface of the first reflector such that the focusing axis is parallel to the focusing axis of the first reflector and the direction of the beam.

Therefore, the cross-polarized waves generated by parallel elements on the surface of each reflector
wave) is the desired polarization (co-polar) of each reflector.
1zed) Desired polarized waves scattered off the beam and generated by each reflector are transmitted parallel to a predetermined common direction.

The present invention will be described below with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows a satellite antenna device 10 attached to a structure 11 of a satellite.

The antenna device 10 includes reflectors 12, 13.15 and 1
7 and waveguide feeding horns 19a, 19b, 19c and 1
9d.

The reflectors 12, 13.15 and 17 are the supports 12a, 13
a, 13b, 15a.

It is fixed to the structure 11 of the satellite by 17a and 17b.

The struts 13b and 17b are the horns 19b and 19d in Figure 1.
I can't see it because it's hidden behind it.

As is clear from the side view of reflector 15.17 in Figure 2,
The reflector 15 has a support 15a passing through it and an end 16 thereof.
is supported by being fixed to one end of columns 17a and 17b.

The reflector 15 is attached to the posts 15a, 17 by suitable adhesive means.
a and 17b.

The reflector 17 has two pillars 17a and 1 passing through it.
7b and its end 16a is supported by fixing it to a post 15a directly behind the reflector 15.

The strut 17b passes through only the end of the reflector 17.

The reflector 17 is attached to the supports 15a, 17 by suitable adhesive means.
a and 17b.

Post 12a. 13a and 13b similarly have the reflector 12 fixed in front of the reflector 13 and the reflector 13 fixed behind the reflector 12.

Suitable materials for such support columns include carbon fiber epoxy composition e7 (gr-apite f
There is a material with a low coefficient of thermal expansion known as rGFEcJ, which stands for iber epoxy composite.

Reflectors 12, 13, 15 and 17 are each part of a paraboloid of revolution.

A portion 21 of the paraboloid of revolution shown in FIG.
It corresponds to

Further, the portion 21a corresponds to the reflector 17. Reflector 1
2 and 13 are the above portion 2 shown by the dotted line of the paraboloid of revolution.
Although it is the same as No. 1 and 21a, it uses a symmetrical part.

The long edges of each of these parts pass through the vertices of the paraboloid.

Portion 21 covers more than half of portion 21a.

The vertex ■ is located along the long edge of the portions 21 and 21a.

Vertex V is located midway between the long edges of portion 21a and
It is located approximately one-third from one end of 1.

The position of the reflectors is placed near the center of the rotating paraboloid so that they overlap very closely and no interfering polarization fields occur.

As is clear from FIG. 1, reflectors 12 and 13 overlap each other, and reflectors 15 and 17 also overlap each other.

The reflector 12 overlaps about half of the reflector 13.

Similarly, reflector 15 overlaps approximately half of reflector 17.

The reflectors are stacked such that the long edge of the front reflector overlaps the long edge of the reflector behind it.

For example, referring to FIG. 4, reflector 15 overlaps reflector 17 such that their long edges overlap.

As shown in FIG. 4, apex 23 of reflector 15 is aligned with and has a spacing therebetween.

Reflectors 15 and 17 are arranged evenly symmetrically such that their flatter ends are one near their apexes.

In other words, if you place a mirror on the midline of the overlap and cover the upper half, the reflected image of the lower half will produce the same image as the covered upper half.

The same applies to the arrangement of reflectors 12 and 13.
The same can be said of a trench in which the reflector 2 is placed in front of the reflector 13, that is, further away from the structure 11.

The apex 23a of the reflector 12 is aligned with and spaced apart from the apex of the reflector 13.

Reflectors 12, 13, 15 and 17 are made of parallel conductive elements, as indicated in part by parallel lines in FIGS. 1 and 4.

The parallel elements of reflectors 12 and 17 are indicated by longitudinal parallel lines 2T and 29, respectively.

The parallel elements of reflectors 13 and 15 are indicated by horizontal parallel lines 31 and 33, respectively.

The elements forming reflectors 13 and 15 extend at right angles to the elements forming reflectors 12 and 17.

The parallel elements that make up these reflectors can be made of narrowly spaced parallel wires embedded in a low-inductivity plastic matrix.

The lines are arranged so that when viewed from a distance along the axis of the paraboloid formed by them, they are parallel to each other and to the electric field produced by the desired polarized feed coupled thereto. has been done.

Feed horn 19a is designed to couple signals over a frequency band of predetermined width and is polarized to transmit vertically polarized waves.

This feeding horn 19a is fixed by a support part 51 extending from the satellite structure 11 as shown in FIG.

The feeding horn 19a is fixed such that its hole is located at the focal point of the polarized reflector 12.

The feeding horn 19a is further fixed so that the radiation direction of the reflector 12 is optimized.

Feed horn 19b is designed to couple signals over the same frequency band as feed horn 19a, but this feed horn 19b is polarized to transmit horizontal polarization.
is fixed by a support part 53 extending from the satellite structure 11 to place its aperture at the focal point of the polarizing reflector 13.

Further, the feeding horn 19b is attached in such a direction that the radiation direction of the reflector 13 is optimized.

Feed horns 19c and 19d are polarized to transmit horizontally and vertically polarized waves, respectively.

Horns 19c and 19d are designed to combine signals over the same frequency band.

This frequency band may be the same as the predetermined frequency band or may be another frequency band.

In the embodiment shown here, horns 19a, 19b.

19c and 19d are designed to transmit signals over the same frequency band.

The small frequency band portion or channel within this wide frequency band transmitted by horns 19a and 19b of the device shown here is different from the small frequency band portion transmitted by horns 19c and 19a.

For example, horns 19a and 19b transmit odd channels, and horns 19c and 19d transmit even channels.

This reduces the problems associated with multiplexing those signals.

Similarly, the horn 19c is fixed by a support part 55 at the focal point of the (horizontal) reflector 15 given the desired polarization, and the horn 19d is fixed by the support part 57 to the focal point of the (vertical) reflector 17 with the desired polarization. is fixed in focus.

FIG. 2 shows the support parts 55 and 57 and the horns 19c and 19.
d and the structure 11 is clearly shown.

Feed horns 19a, 19b, 19c and 19d are positioned within structure 11 by waveguides, such as waveguides 59 and 61 of FIG. 2, extending between feed horns 19c and 19d, respectively, and structure 11. The transmitter circuit is coupled to a transmitter circuit and a receiver circuit.

The feed horns 19c and 19d each further include a reflector 1.
5 and 17 in an orientation that optimizes radiation.

The vertical elements of reflectors 12 and 17 transmit horizontally polarized waves and reflect vertically polarized waves.

The horizontal elements of reflectors 13 and 15 transmit vertically polarized waves and reflect horizontally polarized waves.

The overlapping regions 18 and 20 of FIG. 1 reflect both horizontally and vertically polarized waves.

With reference to the explanatory diagram of FIG. 5, consider the operation of the antenna device when the transmitted vertically polarized wave is directed toward the reflector 12.

The wave radiated towards the reflector 12 by the horn 19a placed at the focal point f1 of the reflector 12 is indicated by the dotted line 26 in FIG.

The wave is intercepted by a reflector 12 having a vertical element, directed to the antenna hole in phase (becomes a plane wave), and is directed at the arrow 2
A beam of radiation with a predetermined direction, indicated by 8, is obtained.

The apex 23a of the reflector 12 is connected to the reflector 1 as shown in FIG.
It is on one end side 12a of 2.

Since the horn 19a is located at the focal point of the reflector 12 and on the same line as and in front of the apex 23a, the horn 19a
There is little interference with vertically polarized waves.

A reciprocal operation occurs for the received in-phase wave at the antenna hole.

These in-phase waves arriving at the hole are reflected towards the horn 19a.

If horizontally polarized waves are sent towards the reflector 13 by the horn 19b placed at the focal point f2 of the reflector 13, these waves, indicated by the dotted line 36 in FIG. are cut and brought into phase (plane wave) at the antenna hole to obtain a radiation beam in the same predetermined direction, arrow 28 in this example.

Since the apex 25a of the reflector 13 is located on one end of the reflector 13, and the horn 19b is located at the focal point f2 on the same line as the apex, there is little interference with the horizontal polarization of the horn 19b.

As explained below, a portion of the vertically polarized wave, indicated by dotted line 26, is transmitted through reflector 12 (not reflected).

In the common region 18, their transmitted parts have an interfering (horizontal) polarized electric field 26h (observed by the reflector 12).

This electric field 26h is transmitted and reaches the reflector 13.

Therefore, that part is reflected at 13 (see Figure 5).

Although considerable effort has been made to create perfectly parallel vertical elements of reflector 12, indicated by line 27 in FIG. 1, there is some interference ( (horizontal) polarized electric field is generated.

This means that parallel elements cross the long edge 1 that intersects the apex 23a.
This can be partially explained by the slight shift in polarization of the wave near the edge 22 furthest from 2d.

FIG. 6 is an enlarged view of a portion of several elements 27 indicated by lines near the edge 22 of the reflector 12, and a schematic diagram showing the desired polarized waves 27a incident on those elements and their vector components. It is a vector diagram.

For the sake of explanation, the deviation of the polarization vector 27a with respect to the line 27 is exaggerated.

If the reflector element 27 is shifted with respect to the polarization direction of the incident wave indicated by the vector 27a, the vertical vector component 27c
A horizontal vector component 27b is generated outside of .

This shift in the incident electric field is due to the change in polarization direction that occurs in the incident wave when it makes a large angle to the focal axis.
(increases as the wave moves away from the focal axis).

The electric field incident on those reflectors therefore creates an interfering (horizontal) electric field.

This electric field is indicated by the dotted line 26h in FIG.

The reflectors 12 and 13 are made to overlap near their respective vertices so that in their overlapping regions this deviation is small and therefore its effect is small.

Furthermore, by arranging the focal points f and f2 of the two reflectors 12 and 13 at a sufficient distance as shown in FIG. The interfering polarized electric field 26h at 26h) deviates from the beam direction 28 associated with the vertically polarized reflector and at the same time deviates from parallel paths.

Similarly, the vertically polarized electric field created in the horizontally polarized conductor 31 of the reflector 13 deviates from the horizontally polarized beam.

Although there is considerable benefit in making the horizontal elements of reflector 13, indicated by lines 31 in FIG. Some interfering (vertically) polarized electric field is generated (indicated by the dotted line 36v in the figure).

This is due to the fact that the reflector elements are slightly offset relative to the polarization direction of the wave, as shown by the wave near end 22a in FIG.

FIG. 7 is a partially enlarged view of several elements indicated by lines 31 near the end side 22a of the reflector 13 and an exaggerated vector diagram of desired polarized waves incident on those reflecting elements 31.

Note that if the reflector element 31 is offset with respect to the polarization direction of the incident wave along vector 31a, there will be a vertical vector 31b outside of the horizontal vector 31c.

This shift is due to the change in the polarization direction of the incident wave when the wave makes a large angle to the focal axis.

Therefore, an interfering (vertical) electric field of 36v is created.

Two reflectors 12 as previously described and shown in FIG.
By placing the focal points f1 and f2 of and 13 a sufficient distance apart, this interfering polarized electric field 36v at reflector 13 is deflected from the main horizontally polarized beam in direction 28.

If the received horizontal polarizations generate interfering (vertical) polarizations at reflector 13, those interfering (vertical) polarizations are shifted at reflector 13 to either horn 19a or 19b.

In the above-described structure, it is not preferable to place the focal point f 25.4 mm apart from the focal point f2 and to arrange the apex 23a at a distance from the apex 25a such that the focusing axis of the reflector 12 is parallel to the focusing axis of the reflector 13. The interference polarization is shifted by 20 degrees from the desired direction of the communication signal (direction 28 in FIG. 5).

Considering that this antenna device is in satellite orbit,
With this 20 degree shift, undesired interference polarized waves can be sufficiently removed from the earth. Considering polarization, these waves 46 incident on the reflector 15
is collimated and projected in that direction as a beam in the same direction as the waves reflected by the reflectors 12 and 13, for example.

In the case of a vertical wave transmitted to the reflector 17 by the horn 19d placed at the focal point f4 of the reflector 17, the reflector 17
Those waves 56 incident on the reflectors 12, 13 and 15, for example, become parallel waves in the same direction as beams in the same direction as the reflected waves.

The apex of each of reflectors 15 and 17 is on one edge of those reflectors as shown in FIG.

The feeding horn 19c is arranged at the focal point f3 of the reflector 15,
The feeding horn 19d is arranged at the focal point f4 of the reflector 17.

Since the apex is along one edge of each reflector, there is less interference to received or reflected waves.

Horn 19d passing through common area 20 shown in FIG.
The vertical wave 56 from 15 is transmitted through the reflector 15 and reaches the reflector 17, where it is reflected.

As mentioned above, a degree of interference (horizontal) polarization is generated as indicated by the dotted line 56h, which is caused by the two reflectors 15 and 1.
Since the focal points f3 and f4 of 7 are separated by a sufficient distance, they are deviated from the desired direction as described above.

In the case of a horizontally polarized wave 46 passing through the reflector 15 in the common area 20, an interfering (vertical) deflection electric field 46v is generated and incident on the reflector 17.

As mentioned above, the focal points f3 and f4 of the two reflectors are sufficiently far apart that their interfering polarized electric fields are deviated from the desired direction.

The reversibility principle can be applied to the operation of the antenna structure described herein.

Therefore, everything that happens in the transmit mode described above is reversed in the receive mode.

The above-described configuration shows that the invention is effective for realizing a communication device that has advantageous reflection properties, particularly with respect to dimensions parallel to the beam direction 28, and that can be miniaturized.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the invention. Front enlarged view of the satellite antenna device installed on the satellite, 2nd
The figure is an enlarged side view along line 2-2 in Figure 1, and Figure 3 is an enlarged side view along line 2-2 of Figure 1.
4 is an enlarged front view showing the relative arrangement of the two reflectors in FIG. 1, and FIG. A diagram for explaining the operation of the first pair of reflectors of the antenna device,
Figure 6 shows a portion of several vertical elements of one reflector and the vector of polarized waves incident on those elements, and Figure 7 shows a portion of several horizontal elements of one reflector. FIG. 8 is a diagram illustrating the vectors of polarization incident on those elements for explaining the operation of the other pair of overlapping reflectors and the associated feeder of the antenna arrangement shown in FIG. It is a diagram. 10... Antenna device, 11... Satellite structure, 12.13. (15, 17)... Electromagnetic wave reflector, 19a, 19b (19c, 19d)...
- Radiation means, 27.31 (29, 33)... Electromagnetic wave reflecting element.

Claims (1)

[Scope of Claims] 1. A microwave antenna device comprising first and second feeding means for transmitting orthogonally polarized first and second waves forming a beam, the microwave antenna device comprising first and second feeding means for transmitting orthogonally polarized first and second waves forming beams, two grating devices mounted in combination one on top of the other such that the parallel reflector elements of the other are at right angles to the parallel reflector elements of the other; and said first feeding means, in which the focus of said first reflector is arranged.
forming a surface of a parabolic reflector, and said other grating device comprising a second feeding means cooperating with said second wave and said second feeding means disposed at the focal point of said second reflector. a surface of the second parabolic reflector; The surface of the second parabolic reflector has a focal axis such that the focal axis of the second reflector is located at a sufficient distance from the focal point of the first reflector. A microwave antenna device, wherein the microwave antenna device is arranged to be displaced from a surface of the first reflector so as to be parallel to a focusing axis of the first reflector and the direction of the beam.