JPH0766622A - Mesh material for antenna reflection mirror surface - Google Patents

Abstract

PURPOSE:To contribute to accelerate turning bands multiple and turning beams multiple and to effectively prevent the generation of a PIM phenomenon. CONSTITUTION:By sticking an insulated coating film 10b on the surface of the conductive body 10a of a conductive wire 10 composed by being weaven in a mesh-shape, the insulated coating film 10b is interpolated between the conductive body 10a of the conductive wire 10 weaven in the mesh-shape. Then, the presence of a contact point is prevented and the generation of the PIM phenomenon accompanying electric field fluctuation and discharge in a minute part due to the contact point can be surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna reflecting mirror surface mesh material used for forming a reflecting mirror surface of a mirror antenna mounted on, for example, an artificial satellite.

[0002]

2. Description of the Related Art As is well known, in a mirror antenna, as a means for improving the characteristics, it is indispensable to increase the diameter of the antenna reflecting mirror surface and to improve the shape accuracy. As a method of obtaining a highly accurate mirror surface precision with such a large diameter, it is advantageous to form an antenna reflecting mirror surface using a mesh material having flexibility and elasticity as well as flexibility. The antenna reflecting mirror surface using this mesh material is small in deformation due to its own weight because the supporting structure can be made small. In addition, it has the advantage that it can be easily transported and installed in tall buildings and remote areas of mountains, and that rainwater and snowmelt water can be easily drained from the reflecting mirror surface. Further, when such a mirror antenna is constructed in outer space, it has an advantage that it is easy to secure a launch fairing space because the antenna reflecting mirror surface can be easily folded and unfolded.

FIG. 2 shows such a mirror antenna, in which a mesh mirror surface 1 on which a mesh material is spread is disposed via a support structure 2, and a power feeding portion 3 is provided on the mesh mirror surface 1 as a power feeding supporting member. They are arranged opposite to each other. Since this mesh material is required to have a high mirror surface precision of the mesh mirror surface 1, the mesh material is stretched and set to a desired mirror surface precision in a state where the support structure 2 is assembled. Wires such as electrically conductive fibers, which are rich in flexibility and elasticity and have desired electrical characteristics, are woven into a mesh shape.

By the way, in the recent communication field, multi-band and multi-beam are being promoted with the diversification of communication satellites. It is said that it is advantageous to configure the antenna reflecting mirror surface with a mesh material, because such a mirror surface antenna requires a larger size of the antenna reflecting mirror surface and higher accuracy. As such a conventional mesh material, US Patent (US Patent N
unber: 4,609,923, Date of Patent: Sep.2,1986), which uses a gold-plated molybdenum wire or a tungsten wire. Since the conductive material of the molybdenum wire or the tungsten wire, which is the base line, is easily oxidized in this mesh material, it is woven into a mesh shape after being subjected to the gold plating treatment and then the mesh mirror surface 1 (see FIG. 3). (See) is formed.

However, in the mesh mirror surface formed of the above mesh material, there is a so-called metal-to-metal contact point between the surfaces of the wire material. Therefore, when frequency sharing is performed and a multi-beam is formed, the pim ( PIM: Passive Inter M
However, there is a problem in that it is difficult to stably transmit and receive a signal due to the occurrence of an "odulation" phenomenon. That is, at the contact point, a desired tension is applied so as to form an ideal mirror surface, so that the contact area and pressure change at each part of the mirror surface, and the discharge or contact resistance change or metal A non-linearity occurs in the current induced by an incident radio wave such as an electron tunnel effect through the oxide film on the surface, and a pim phenomenon occurs.

[0006]

As described above, the conventional mesh material for antenna reflectors has a problem that a pim phenomenon occurs when frequency sharing is performed.
The present invention has been made in view of the above circumstances, and provides a mesh material for an antenna reflecting mirror surface that effectively prevents the occurrence of a PIM phenomenon so as to contribute to promotion of multi-beam formation as well as multi-band formation. The purpose is to

[0007]

According to the present invention, in a mesh material for an antenna reflecting mirror surface, which is formed by weaving a wire material into a mesh shape, at least the surface layer of the wire material is formed of a conductor, and the surface of the conductor is insulated. It is made to be covered with a sex coat.

[0008]

According to the above structure, in the wire woven in the mesh shape, the contact points between the conductors are not present due to the interposition of the insulating coating. Therefore, the occurrence of the pim phenomenon due to the non-linearity in the minute portion due to the contact point is eliminated.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a mesh material for an antenna reflecting mirror surface according to an embodiment of the present invention, which is a conductive wire material 10 constituting the mesh mirror surface 1. That is, the conductive wire 10 has, for example, a surface of a conductor 10a made of a molybdenum metal alloy having a wire diameter of 20 μm, and an insulating coating 10b of, for example, Si3N2 having a thickness of 0.5 μm formed by plasma CVD or thermal CVD. Be worn.

The conductive wire 10 is twisted in a plurality of, for example, four (twisting frequency: once / 25 mm) to form a bundle, and the bundle is formed by using a tricot knitting machine, for example, 2
The mesh mirror surface 1 (see FIG. 2) is formed by weaving a mesh having a size of mm × 2 mm to form a mesh and cutting the mesh into a desired shape having a diameter of 2.5 m, for example. As a result, in the state where the conductive wire 10 is woven in a mesh shape on the mesh mirror surface 1, the insulating coating 10b is interposed between the conductors 10a of the conductive wire 10 and is in contact with the mesh mirror surface 1. No longer exists. As a result, the mesh mirror surface 1 has a pim (PI) that accompanies a discharge or electric field fluctuation in a minute portion due to a contact point as in the related art.
M) The occurrence of the phenomenon is surely prevented. This is for example P
Confirmed by conducting an IM evaluation test. That is, as the PIM evaluation test, first, the mesh is set to 50
The test piece A was cut into a size of 50 mm × 50 mm, and the test piece A was mounted between the waveguides of the PIM evaluation test device shown in FIG. 3, for example.
Then, as an antenna characteristic test, the transmittance of the mesh mirror surface at 14 GHz was measured, and the reflectance was measured from the result. As a result of this evaluation test, it was confirmed that the PIM phenomenon did not occur as shown in FIG. 3, and the antenna characteristics thereof were 98% to 99%, which was a very good evaluation.

As a comparative example, a conductive material made of a molybdenum metal alloy having a wire diameter of 20 μm and coated with gold (Au) having a thickness of 0.5 μm by an electroplating method has no insulating coating. Similarly, a mesh was formed using a flexible wire, and the mesh mirror surface 1 (see FIG. 2) was formed by cutting the mesh into a desired shape such as a diameter of 2.5 m. Then, for the PIM evaluation test, a mesh of, for example, 50 mm × 50 mm is used.
The test piece C is cut by cutting into the
A PIM evaluation test and a reflectance measurement test were performed using an M evaluation test apparatus. As a result of this, as shown in FIG. 3, a good evaluation was obtained that the reflectance showing the anten characteristic was 98% to 99%, but the insulating coating 10 which is a feature of the present invention.
Since b was not formed, the PIM phenomenon occurred due to the contact points existing between the conductors of the conductive wire.

As described above, the mesh material for the antenna reflecting mirror surface is a conductive wire 10 woven in a mesh shape.
By coating the surface of the conductor 10a with the insulating coating 10b, the insulating coating 10b is interposed between the conductors 10b of the conductive wire material 10 woven in a mesh shape and is in contact with the conductor 10b. Therefore, the occurrence of a PIM (PIM) phenomenon due to a discharge or electric field fluctuation in a minute portion due to the contact point is reliably prevented. It is confirmed that the presence or absence of the PIM phenomenon does not occur as shown in FIG. 4 by performing the PIM evaluation test as described above. As the antenna characteristics, as described above, the reflectance is 98% to 9% as shown in FIG.
A very good evaluation of 9% was obtained, and substantially the same effect was obtained when the surface layer was formed of a conductor. As a result, it is possible to contribute to the realization of multi-beams and multi-bands capable of frequency sharing.

In the present invention, as the conductive wire 20, for example, as shown in FIG. 5, a surface of a conductor 20a made of a molybdenum metal alloy having a wire diameter of 20 μm is first formed by electroplating to a thickness of 0.5 μm. Dimension only gold (Au) layer 20
b is deposited, and a 0.5 .mu.m thick SiO.sub.2 insulating coating 20c is deposited on the gold layer 20b by, for example, a silane coupling agent coating method and a thermal decomposition method. good. According to this, a plurality of conductive wire members 20,
For example, 4 pieces (twisting frequency: 1 time / 25 mm) are twisted to form a bundle, and the bundle is formed using a tricot knitting machine, for example,
The mesh is woven into a 2 mm × 2 mm mesh, and the mesh is, for example, 50 mm for the PIM evaluation test as described above.
A test piece B is formed by cutting at × 50 mm, and P shown in FIG.
By mounting the IM evaluation test device between the waveguides and performing the evaluation test, it is confirmed that the PIM phenomenon does not occur. Similarly, the antenna characteristics are 14 GHz.
By measuring the transmittance of the mirror surface of the mesh and measuring the reflectance from the result, a good evaluation of 98% to 99% can be obtained.

In the above embodiment, the conductive wire 10,
Although 20 is composed of a molybdenum metal alloy, it is not limited to this, but metal alloy wires such as tungsten, piano, stainless steel, niobium wire, carbon fiber, sic fiber, B fiber, si3N4 fiber, BN fiber, Al203 fiber, etc. , An sio2 fiber or the like, a aramid fiber, a polymer fiber such as a polyimide fiber, or the like can be applied as long as a conductor can be formed on the surface layer, and a similar effect is expected.

Further, in the above embodiment, the insulating coating 10
The description has been made on the case where the inorganic substances of Si3N4 and S1O2 are formed as b and 20c.
, The same effect can be expected by forming an inorganic material such as ZiO2 or an organic material such as epoxy resin, polyimide resin, PTFE, silicone resin, PEEK. And as means for forming an insulating film, spraying, vapor deposition, coating,
It can be carried out by various methods such as dipping, CVD and sputtering. Therefore, it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

[0016]

As described in detail above, according to the present invention, the antenna reflecting mirror surface mesh effectively prevents the occurrence of the pim phenomenon so as to contribute to the promotion of multi-beam formation as well as multi-band formation. Material can be provided.

[Brief description of drawings]

FIG. 1 is an enlarged view showing a mesh material for an antenna reflecting mirror surface according to an embodiment of the present invention.

FIG. 2 is a diagram showing a specular antenna using the mesh material of FIG.

FIG. 3 is a diagram showing a PIM evaluation test device for testing the presence or absence of the PIM phenomenon.

FIG. 4 is a diagram showing the evaluation test results of FIG.

FIG. 5 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Antenna reflecting mirror surface, 2 ... Support structure, 3 ... Feeding unit,
4 ... Power feeding part supporting member, 10, 20 ... Conductive wire, 10
a, 20a ... Conductor, 10b, 20c ... Insulating film, 2
0b ... Gold layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location H01Q 25/00 2109-5J (72) Inventor Tatsukichi Osaka 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Address Stock Company Toshiba Komukai Factory (72) Inventor Kyoko Tokunaga 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki City, Kanagawa Prefecture Kobayashi Factory Stock Company (72) Inventor Koichi Furukawa Kawasaki, Kawasaki City, Kanagawa Prefecture Komukai Toshiba Town No. 1 Inside Toshiba Corporation Komukai Factory

Claims (1)

[Claims] 1. A mesh material for an antenna reflecting mirror, comprising a wire material woven into a mesh, wherein at least a surface layer of the wire material is formed of a conductor, and the surface of the conductor is covered with an insulating coating. Characteristic mesh material for antenna reflector.