JPH0779207B2 - Metal mesh reflector antenna - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal mesh reflector antenna used as a deployable antenna or the like.

[0002]

2. Description of the Related Art Conventionally, as a metal mesh reflector antenna, those shown in FIGS. 9, 10, and 11 are known. The antenna 1 shown in FIGS. 9 and 10 is
`` The American institute of Aeronautics and Astron
autics ”12th [International Communication Satell
ite Systems Conference AIAA-88-0875 ”. The antenna 2 shown in FIG. 11 is described in "Journal of the Institute of Electronics, Information and Communication Engineers B, Vol. J71-B, No. 6,".
pp. 764-771 "(1988-6). In these figures, 3 is a back structure, 4 is a metal mesh, 5 is a surface wire, 6 is a back wire, and 7 is a primary radiator.

These antennas 1 and 2 have a back structure 3
A reflection surface is formed by stretching the metal mesh 4 on the surface of the metal mesh 4, and the surface wire 5 having a stronger elastic force than the metal mesh 4 is provided on the same plane as the metal mesh 4. The reflecting surface is configured to have a desired curved surface shape by being pulled by another back surface wire 6. Then, the radio waves radiated from the primary radiator 7 and propagating in a spherical shape are generated by the back structure 3 and the metal mesh 4.
By the reflective surface of the paraboloid of revolution composed by
It is converted into a radio wave propagating in a plane and concentratedly emitted in a desired direction. On the contrary, radio waves coming from a sufficiently distant place are reflected by the reflecting surface and then concentrated on the primary radiator 7 so that they can be efficiently received.

Mechanically, in order to provide the reflecting surface with a function of being developed and stored and to reduce the weight, the back structure 3 has a trust structure in which rod-shaped members are combined, and the reflecting surface is made of a metal thread. It is composed of a woven metal mesh 4. Further, in order to set the shape of the reflecting surface to a desired curved surface shape such as a paraboloid of revolution, a surface wire 5 having a stronger elastic force than the metal mesh 4 is formed on the same plane as the metal mesh 4 on the back surface. The structure is such that the other back surface wire 6 is pulled from the direction, and the length and tension of each of these wires 5, 6 can be adjusted.

[0005]

However, in the above-mentioned conventional metal mesh reflector antenna, the reflecting surface is shown in FIGS. 10 and 11 by the back structure, the metal mesh, and various wires for shape adjustment. like,
It is composed of an orderly combination of many triangular planes (facets), but there is a problem that each facet deviates from an ideal curved surface such as a paraboloid of revolution to cause a mirror surface error, which deteriorates the radiation pattern. In particular, there is a problem that the side lobe level increases in the wide angle direction.

For example, in the case of the conventional antenna shown in FIG. 10, there are periodic mirror surface errors because the radial divisions that define the size of the facets are at regular intervals, and as shown in FIG. There was a problem of producing a large level of grating lobe. Further, in the case of the conventional antenna shown in FIG. 11, a method of discontinuously increasing the facet of the peripheral portion with respect to the central portion is adopted in order to reduce the periodicity, but it is sufficient for suppressing side lobes. No such effect is exerted, and in addition, mechanically, in the discontinuous portion, the number of wires is 6 at the intersection point C and 4 at the intersection point D, so the strength is reduced at the boundary portion between the central portion and the peripheral portion. However, there are problems that it bends in a V shape at the time of unfolding, a step is formed on the mirror surface of the boundary portion, and it is difficult to balance tension at the intersections of the wires existing in the discontinuous portion.

Further, in the conventional antenna, in order to reduce the grating level, it is necessary to sufficiently increase the number of divisions in the radial direction, which causes a problem that the weight increases and the amount of shape adjustment work increases. . Therefore, the present invention is
The reflecting surface can be continuously changed without increasing the weight and the amount of adjustment work, and the tension balance at the intersection of each surface wire can be easily adjusted. An object of the present invention is to provide a metal mesh reflector antenna that can sufficiently suppress the level of the grating lobe without increasing it.

[0008]

In the metal mesh reflector antenna of the present invention, a metal mesh forming a reflecting surface is stretched on the surface of a back structure, and is more elastic than the metal mesh on the same plane as this metal mesh. A plurality of front surface wires having a force are arranged, and by pulling these front surface wires from another back surface wire by another back surface wire, in the metal mesh reflector antenna that can set the reflecting surface to a desired curved shape, The surface wire, a plurality of radial wires radially arranged from the central portion of the reflecting surface to the peripheral portion, and arranged at unequal division intervals from the central portion of the reflecting surface to the peripheral portion, The surface wire is composed of a plurality of circumferential wires connecting adjacent radial wires and a plurality of connecting wires connecting adjacent circumferential wires, and the surface wire except for the outermost peripheral portion. The intersections of the wires are supported by six wires that are a combination of the radial wire, the circumferential wire, and the connecting wire, and the unequal division intervals of the radial wire are the outermost circumference with respect to the innermost circumference. The ratio of the dividing intervals is within a range of 1.5 to 3 times, and the dividing interval of the intermediate portion from the innermost circumference to the outermost circumference is continuously increased toward the peripheral portion. It is characterized by

[0009]

Therefore, since the circumferential wires are arranged at unequal division intervals in the radial direction of the reflecting surface, the existence of mirror surface errors becomes irregular, and the grating lobe level increases the number of divisions in the radial direction. Can be sufficiently suppressed without.
Further, since the intersections of the front surface wires are supported by the six wires and the positions are held by the rear surface wires, it is possible to easily balance the tension at the front surface wire intersections. Further, since it is not necessary to increase the number of divisions by the circumferential wire in the radial direction as compared with the conventional case, the weight is not increased and the work amount for shape adjustment is not increased.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a front view of a reflecting surface of a metal mesh reflector antenna 10 according to this embodiment. In this embodiment,
The front shape is a regular hexagon, and the reflecting surface is divided into four in the radial direction by a circumferential wire 5b described later. Further, the structure of the metal mesh reflector antenna 10 is basically the same as that of the conventional metal mesh, as in the conventional case shown in FIG. A plurality of surface wires 5 having a stronger elastic force than the metal mesh are provided on the plane, and the surface wires 5
By pulling from the back side with another back side wire, the reflecting surface can be set to a desired curved shape.

The surface wires 5 include radial wires 5a, circumferential wires 5b, and connecting wires 5.
It is composed of c ... A plurality of radial wires 5a (6 wires) are radially provided from the central portion A of the reflecting surface to the peripheral portion.
They are arranged and the angles in the circumferential direction are equal. The circumferential wires 5b are the adjacent radial wires 5a, 5
a of the reflecting surface is connected to each other at the same distance from the center, and a plurality of (24
Book) is provided. In the present embodiment, the circumferential wires 5b are arranged at unequal intervals such that the distance from the central portion A to the peripheral portion continuously increases. Connecting wire 5c
Is for connecting the circumferential wires 5b, 5b that are adjacent to each other in the radial direction, and a plurality of wires are arranged between them so that their angles are different from each other.

More specifically, between the pair of radial wires 5a and 5a, both ends of the first circumferential wire 5b and the second circumferential direction are counted outward from the central portion A of the reflecting surface. A plurality of (three) triangular facets are formed between the wires 5b and 5b by arranging the connecting wires 5c that connect the midpoints of the wires 5b. Similarly, between the pair of radial direction wires 5a and 5a, the middle point of the second circumferential direction wire 5b and the three points at both ends
By arranging a connecting wire 5c, which connects a point and two points that divide the third circumferential wire 5b into three equal parts and four points at both ends, a plurality of (5 3) triangular facets are constructed. Similarly, in the third circumferential wire 5b and the fourth circumferential wire 5b, a plurality (7
3) triangular facets are constructed. And
Similarly, by arranging the connecting wires 5c between the other radial wires as well, the entire mirror surface of the reflecting surface is configured to have a plurality of triangular facets.

The metal mesh reflector antenna 1 of this embodiment
According to 0, each wire 5a, 5b, 5c except the outermost peripheral portion
The intersection point B is supported by six combinations of these, and is held in a pulled state by the back surface wire to be set to a desired curved surface shape. In this case, since the radial divisions by the circumferential wires 5b are continuously unequal intervals, it is possible to cause mirror surface errors to exist irregularly, and it is possible to sufficiently suppress the level of the grating lobe. The sidelobe level can also be lowered.

For example, the results of the tests conducted by the present inventors are shown in FIG.
Through FIG. 2 shows a case where the number M of divisions by the circumferential wire 5b in the radial direction is 4 (FIG. 1), and FIG.
5, the number of divisions M is 6, FIG. 4 shows the number of divisions M, and FIG. As shown in these figures, when the number of divisions M is 4, 5, 6, and 8 and the ratio p of the division intervals is sequentially changed,
It can be seen that the side lobe level becomes the lowest when the ratio p of the innermost circumference interval t1 and the outermost circumference interval tn is approximately doubled among the radial division intervals. The intermediate division interval is set to continuously increase toward the peripheral portion.

The relationship between the number of divisions M and the side lobe level was obtained as a result shown in FIG. In FIG. 6, a curve a shows the characteristic of unequal division as in the present embodiment, a curve b shows the characteristic of even division as in the prior art, and a curve c shows a parabola surface (grating lobe direction at the time of even division). Side lobe level) of the characteristics. FIG. 7 and FIG. 8 show how the reflecting surface is divided and the two-dimensional map of the mirror surface error at each division. As described above, in the present embodiment, the effect is particularly large in the range where the ratio p of the interval (t1, tn) between the innermost circumference and the outermost circumference is 1.5 to 3 times, and the effect is large in the conventional equal division. Compared with the case, the side lobe level at a wide angle can be lowered by about 3 to 8 dB.

Further, since the intersection point B of each wire is supported by the six wires which are combined with each other and the position is held by the back wire, it is possible to easily balance the tension at the intersection point of the wires. Therefore, there is no bending in a V shape or a step on the mirror surface unlike the conventional case. Further, since the side lobe level can be lowered by the ratio p of the distance between the innermost circumference and the outermost circumference, it is not necessary to increase the number of divisions in the radial direction as compared with the conventional case, and the weight and the amount of shape adjustment work increase. Never. Furthermore, since the number of divisions in the radial direction can be reduced, it is possible to reduce the number of parts for adjusting the mirror surface shape,
It is possible to reduce the overall weight and the work amount.

[0017]

As described above, according to the present invention, since the circumferential wires are arranged at unequal intervals in the radial direction, the presence of mirror surface errors becomes irregular, and the circumferential wires are used. The level of the grating lobe can be sufficiently suppressed without increasing the division interval. Further, since the number of intersections of the front surface wires is six and the position is maintained by the rear surface wires, the balance of tension at the front surface wire intersection points can be easily adjusted. Furthermore,
Since it is not necessary to increase the number of radial divisions by the circumferential wire as compared with the conventional case, the total weight and the work amount of shape adjustment do not increase.

[Brief description of drawings]

FIG. 1 is a front view showing a reflecting surface divided by a surface wire according to an embodiment of the present invention.

FIG. 2 is a radiation pattern characteristic diagram at each interval ratio when the number of divisions is four.

FIG. 3 is a radiation pattern characteristic diagram at each interval ratio when the number of divisions is 5.

FIG. 4 is a radiation pattern characteristic diagram at each interval ratio when the number of divisions is 6.

FIG. 5 is a radiation pattern characteristic diagram at each interval ratio when the number of divisions is eight.

FIG. 6 is a characteristic diagram showing a relationship between the number of divisions and side lobe levels.

FIG. 7 is a diagram showing a two-dimensional map of mirror surface division and mirror surface error.

FIG. 8 is a diagram showing a two-dimensional map of mirror surface division and a mirror surface error.

FIG. 9 is a side view of a metal mesh reflector antenna according to a conventional example.

FIG. 10 is a semi-crushed front view of a metal mesh reflector antenna.

FIG. 11 is a front view of another type of metal mesh reflector antenna.

FIG. 12 is a diagram showing radiation pattern characteristics.

[Explanation of symbols]

 5 Surface Wire 5a Radial Direction Wire 5b Circumferential Direction Wire 5c Connecting Wire 10 Metal Mesh Reflector Antenna A Center Part t1 Innermost Side Divided Interval tn Outermost Side Divided Interval

Claims (1)

[Claims] 1. A metal mesh forming a reflecting surface is stretched on the surface of a back structure, and a plurality of surface wires having elasticity more than that of the metal mesh are arranged on the same plane as the metal mesh. In the metal mesh reflector antenna that can set the reflecting surface to a desired curved shape by pulling the front surface wire from the back direction with another back surface wire, the front surface wire is a peripheral portion from the center of the reflection surface. A plurality of radial wires radially arranged on the reflecting portion, and a plurality of circumferential wires connecting the adjacent radial wires arranged at unequal division intervals from the central portion to the peripheral portion of the reflecting surface. And a plurality of connecting wires connecting adjacent circumferential wires, and the intersection point of the surface wires excluding the outermost peripheral portion is the radial wire or the circumferential wire. And the radiating wires are supported by six combined wires, and the unequal division intervals of the radial wires are within a range of 1.5 to 3 times the ratio of the outermost circumference to the innermost circumference. And from the innermost circumference to the outermost circumference
The division interval of the middle part is continuous as it reaches the peripheral part
A metal mesh reflector antenna, wherein the metal mesh reflector antenna is configured to increase in number .