JP2006081041A - Parabolic antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the joining structure of a radio wave reflector in which the number of parts is small, assembling workability is satisfactory, rigidity against wind pressure and anti-earthquake performance are excellent, side lobe suppression is improved, and antenna characteristics are satisfactory. <P>SOLUTION: The parabolic antenna apparatus has at least a redome having a radio wave absorber in at least one part of the internal surface, and a radio wave reflector coupled to the redome. Radio waves leaking to the outside of the radio wave reflector are absorbed by the radio wave absorber and converged into a primary radiator while reducing the side lobe. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a parabolic antenna device, and more particularly to a parabolic antenna device having a radio wave absorber for a radome to improve antenna characteristics.

The parabolic antenna device can collect very weak radio waves efficiently at the center of the radio wave reflector, and thus has been used very often in satellite broadcasting and satellite communication in recent years. Parabolic antenna devices are particularly suitable for microwaves (SHF) that are highly straight and capable of transmitting large volumes of information, and are suitable for trunk lines, radar, BS broadcasts, CS broadcasts, satellite communications, etc. A parabolic antenna device is used.
The parabolic antenna device is often installed at a position considerably higher than the ground, such as the rooftop of a building or the top of a mountain, so that it can withstand vibrations such as wind and earthquakes, and it is lightweight. It is hoped that. In addition, development of a parabolic antenna device having a larger amount of transmitted information and higher communication accuracy is desired.

Such a parabolic antenna apparatus includes a radio wave reflector having a paraboloid for efficiently focusing radio waves, a support for improving the antenna characteristics by joining the radio wave reflector, and a primary radiator for transmitting and receiving radio waves. And mounting fixtures.
In order to improve the antenna characteristics and obtain a parabolic antenna with high communication accuracy, it is effective to reduce side lobes. That is, in an antenna having a radiation directivity such as a parabolic antenna, the antenna gain (the power radiated from the antenna per unit solid angle in an arbitrary direction and the same power as that is supplied to the antenna gain on the vertical axis) The ratio of the power radiated per unit solid angle is expressed in dB, the horizontal axis represents the central axis of the paraboloid of the radio wave reflector, and the angle represents the angle from the central axis. In the directional pattern diagram, small lobes called side lobes are formed on both sides of the central main beam. Since the side lobes cause interference to satellite communication systems or terrestrial communication lines installed elsewhere and are sources of interference from them, it is desirable to reduce them as much as possible.
In order to reduce the side lobe, it is generally known that a radio wave absorber is used to absorb a radio wave that may be adversely affected to reduce the side lobe, but the radio wave reflector is provided with a radio wave absorber. An antenna device has been proposed (Patent Document 1).

  However, in the case of the antenna device, the side lobe is formed by attaching a radio wave absorber directly to the entire periphery of the edge of the reflection surface of the radio wave reflector and absorbing the radio wave reflected by the edge of the reflection surface to reduce the electric field strength. Is to reduce. Further, the closer to the edge, the more the so-called edge level is lowered by increasing the carbon content of the radio wave absorber to increase the absorption. In this way, the wave absorber must be affixed to the entire circumference of the curved reflecting surface so that it does not wrinkle, and the assemblability is poor, and the carbon content of the wave absorber changes as it goes to the edge. There exists a problem that manufacturing efficiency falls by the point made to do.

  For this reason, the support that supports the radio wave reflector suppresses radio waves that leak out of the radio wave reflector, and when the support alone is not sufficient, the radio wave reflection is supplementarily reflected inside the support. A parabolic antenna device that reduces side lobes by applying a body has been proposed.

As shown in FIG. 3, the parabolic antenna device 120 includes a radome 101, a radio wave absorber 102, a support body 103, a radio wave reflector 104, a primary radiator 105, and an antenna holding member 115.
As shown in FIG. 3, the cylindrical support 103 has flange portions 103a and 103b formed at both ends thereof. The radome 101 in which the flange portion 101a having the same shape is formed on the flange portion 103a abuts against the flange portion and is fixed by a coupling member.
On the other hand, the radio wave reflector 104 having the flange portion 104a having the same shape is in contact with the flange portion 103b, and the antenna holding member 115 having the flange portion 115a having the same shape is further in contact with the flange portion. The flanges abut against each other, and the support 103, the radio wave reflector 104, and the antenna holding member 115 are fixed by the coupling member.
As shown in FIG. 3, radio wave reflectors 102 and 102 a are attached to the inner peripheral side surface of the cylinder of the support body 103.

With the above configuration, in the conventional antenna device, the received radio wave can pass through the radome 101 and the support 103, be reflected by the reflection surface of the radio wave reflector 104, and be focused on the primary radiator 105 for reception. The transmission wave radiated from the primary radiator is reflected by the radio wave reflector 104 and is accurately emitted straight to the other party. The side lobes are supplementarily suppressed by the radio wave absorbers 102 and 102a.
In the conventional antenna device, the antenna characteristics shown in FIG. 4 are obtained. The vertical axis in FIG. 4 represents the antenna gain (the power radiated per unit solid angle in an arbitrary direction from the antenna and the power radiated per unit solid angle from the isotropic antenna supplied with the same power as the antenna gain). The horizontal axis represents an angle from the central axis, where the central axis of the paraboloid of the radio wave reflector 104 is 0 degree.

  However, in the case of the conventional parabolic antenna device, as shown in FIG. 3, there is a problem that the shape of the support 103 is complicated, and workability and assembly workability are inferior. Further, only when the radio wave suppression at the support is insufficient, the side lobe is reduced by post-adjustment that the radio wave absorber is attached after assembly, so that the radio wave absorber is placed on the inner peripheral side surface of the support 103 after antenna assembly. The work of attaching 102 and 102a has a problem of reducing the manufacturing efficiency.

JP-A-11-220323

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, an object of the present invention is to provide a parabolic antenna device having a small number of parts, a simple structure, excellent assembling workability, and good antenna characteristics by effectively reducing side lobes.

Means for solving the problems are as follows. That is,
<1> A parabolic antenna device including at least a radome having a radio wave absorber on at least a part of an inner surface thereof, and a radio wave reflector coupled to the radome.
In the parabolic antenna device, since the radio wave absorber is provided in the radome, only radio waves having an adverse effect that cause side lobes are absorbed by the radio wave absorber through the radome, and Radiation directivity is improved.
<2> The parabolic antenna device according to <1>, wherein the radio wave absorber is at least one of a plate shape and a sheet shape.
In the parabolic antenna device, since the radio wave absorber is plate-shaped or sheet-shaped, even if the inner peripheral side surface of the radome is curved, it can be attached along the curved surface, and workability is improved. . And it does not protrude greatly from the said inner peripheral side surface, and does not become an obstacle of a transmitted radio wave.
<3> The parabolic antenna device according to any one of <1> to <2>, wherein the radio wave absorber is formed of a vinylidene chloride synthetic fiber.
In the parabola antenna device, if it is formed of the vinylidene chloride synthetic fiber, there is flexibility, and even if the inner peripheral side surface of the radome is curved, it can be reliably attached along the curved surface.

  According to the parabolic antenna device of the present invention, the conventional problems can be solved. In other words, the present invention can provide a parabolic antenna device having a small number of parts, a simple structure, excellent assembling workability, and good antenna characteristics by effectively reducing side lobes.

-Parabolic antenna device-
The parabolic antenna device according to the present invention includes a radome, a radio wave absorber, a radio wave reflector, and a primary radiator, and is configured by an antenna holding member and other components that are appropriately selected. The radio wave absorber is affixed to the inner peripheral side surface of the radome.

-Radome-
The radome has a function of improving the antenna characteristics by protecting the radio wave reflector and the holding body from foreign matter and preventing interference with external radio waves.
The radome structure is not particularly limited as long as it protects the radio wave reflector and has good antenna characteristics, and can be appropriately selected according to the purpose. However, a single structure is preferable in terms of mechanical strength and workability.
For example, a structure having a cylindrical shape with one end opened and having a fixing portion that can be detachably fixed by a connecting member such as a screw in the opening portion of the holding body can be used.
The size of the radome is not particularly limited as long as it can cover the radio wave reflector, and can be appropriately selected according to the purpose. For example, the outer diameter is slightly larger than the radio wave reflector. The depth is preferably 200 mm or less, and more preferably 10 to 100 mm. This is because if it exceeds 200 mm, the outer shape of the antenna device becomes large, the size is inferior, and the mechanical strength also decreases.
The shape of the radome is not particularly limited as long as the antenna characteristics are good, and can be appropriately selected according to the purpose. For example, the cylindrical bottom may be flat or curved, but the mechanical strength In this respect, a curved surface shape is preferable. Examples of the opening include a flange having a certain width and a flange having a coupling through hole.
The radome material is not particularly limited as long as it has good mechanical strength and antenna characteristics, and can be appropriately selected according to the purpose. Examples thereof include plastic cloth and ceramic cloth. FRP (Fiber Reinforced Plastic) such as epoxy resin containing is preferable in terms of mechanical strength and antenna characteristics. In addition, the relative permittivity and thickness of the radome are selected so that radio waves of a use frequency that protects the radio wave reflector can be transmitted with low loss.
The radome manufacturing method is not particularly limited as long as it can be uniformly formed, and can be appropriately selected according to the purpose. Examples thereof include injection molding, and a lamination method in which a sheet is attached to a mold. Can be mentioned. The surface of the radome is subjected to a surface treatment such as painting in order to improve the weather resistance.

−Radio wave absorber−
The radio wave absorber has a function of improving the characteristics of the antenna by absorbing radio waves having an adverse effect that causes the side lobes, and there are ones corresponding to a wide band and those corresponding to a specific narrow band.
The structure of the radio wave absorber is not particularly limited as long as it has a radio wave absorption function, and can be appropriately selected according to the purpose, such as a single layer, a multilayer, a pyramid shape, a grid shape, and a tile shape. Can be mentioned. These may be used individually by 1 type and may use 2 or more types together.
The material for the radio wave absorber is not particularly limited as long as it has a radio wave absorption effect, and can be appropriately selected according to the purpose.For example, a dielectric loss material, a magnetic loss material, etc. In view of absorption characteristics, dielectric loss materials such as sintered ferrite and vinylidene chloride synthetic fiber are preferable.
There is no restriction | limiting in particular as a shape of the said electromagnetic wave absorber, According to the objective, it can select suitably, For example, although a sheet form, plate shape, a cube, etc. are mentioned, it is 10-40 mm thick in terms of handleability. Sheet shape or plate shape is preferable.
The size of the radio wave absorber is not particularly limited as long as it can be attached to the antenna device, and can be appropriately selected according to the purpose. For example, the size of the radio wave absorber is fixed for convenience of handling such as transportation. It may be formed. Specifically, 500 mm x 500 mm, 1000 mm x 1000 mm, etc. are mentioned. These are used by appropriately cutting them according to the purpose according to the site to be used.
There is no restriction | limiting in particular as a manufacturing method of the said electromagnetic wave absorber, According to the objective, it can select suitably, For example, the combustion synthesis method which synthesize | combines powder material, the method of shape | molding resin, etc. are mentioned.

-Mounting the wave absorber on the radome-
The radio wave absorber according to the present invention is attached to the radome. The mounting position of the radio wave absorber is not particularly limited as long as it is a position that efficiently absorbs radio waves having an adverse effect that causes side lobes and improves the characteristics of the antenna, and can be appropriately selected according to the purpose. For example, it is attached to the entire circumference or at least one place on the inner circumferential side surface of the radome. The reason for using the inner peripheral side surface is that it does not become an obstacle to the passage of transmitted and received radio waves, and is preferable in terms of weather resistance and appearance. By providing at least one location of the radio wave absorber, the radio wave that leaks outward from the radio wave reflector is effectively absorbed by the radio wave absorber and the side lobes are reduced.

−Radio wave reflector−
The radio wave reflector has a function of reflecting transmitted / received radio waves and efficiently focusing them on the primary radiator.

The structure of the radio wave reflector is not particularly limited as long as it has the paraboloid of revolution, and can be appropriately selected according to the purpose, and may be used alone or in combination of two or more. However, a single structure is preferable in terms of workability. For example, the single structure formed with the said paraboloid part and attachment part may be sufficient. The radio wave reflector may be a plate or mesh that is appropriately processed, but is preferably a plate that is processed to efficiently reflect radio waves.
It is preferable that the rotating paraboloid is smooth and uniform in order to efficiently reflect transmitted / received radio waves. The rotating paraboloid portion is formed by a curved surface obtained by rotating the parabola using the characteristics of a parabola in which radio waves entering at any angle are collected at one focal point. The attachment portion is not particularly limited as long as it can be attached to a radome that protects the radio wave reflector, and can be appropriately selected according to the purpose. Examples thereof include a flange structure having a certain width. .

The size of the radio wave reflector is not particularly limited as long as the antenna characteristics corresponding to the frequency used in the transmission / reception radio wave band are favorable, and can be appropriately selected according to the purpose.
For example, in the case of a microwave (SHF, frequency: 3 GHz to 30 GHz, wavelength: 1 to 10 cm), since it has a strong straight traveling property, it is suitable for launching in a specific direction and can be transmitted. Is used for relay lines, radars, satellite communications, satellite broadcasts, and the like that connect telephone stations. The diameter of the radio wave reflector is several tens of centimeters to several tens in consideration of wavelength, antenna gain, and the like. The range can be selected in the range of m. The size of the flange structure is not particularly limited as long as the radome is integrally joined to increase the mechanical strength, but since a through hole for a coupling member such as a bolt is provided, the width is 15-25 mm is preferable. If it is less than 15 mm, the connecting member becomes small and the mechanical strength is lowered, and if it exceeds 25 mm, the area of the joined portion becomes large and the surface pressure is lowered, so that sufficient bonding cannot be obtained.

  The thickness of the radio wave reflector is not particularly limited as long as it can maintain light weight and mechanical strength, and can be appropriately selected according to the purpose. The thickness is selected according to the size and material of the radio wave reflector. . For example, if the material is an aluminum plate and the wave reflector has a diameter of about 1 m, it is preferably 1 to 3 mm, more preferably 1.6 to 2.5 mm, and 2 mm in terms of workability, weight and mechanical strength. Is most preferred.

  The method for producing the radio wave reflector is not particularly limited and can be appropriately selected depending on the purpose. For example, in the case of sheet metal, drawing, pressing, punching, etc., in the case of casting, the shell mold method Etc. The aluminum plate is preferably pressed by a mold. By using a mold, there is no variation in the product, and it can be uniformly produced with high accuracy. Further, in order to ensure durability, it is preferable to apply a cleaning treatment to the surface after processing.

The radio wave reflector can be used for various parabolic antenna devices such as an offset antenna and a Cassegrain antenna.
An offset antenna is an antenna in which only a part of the parabolic surface is used as the main reflector, so that the primary radiator is provided outside the aperture. The received radio wave is reflected by the main reflector and directly into the primary radiator. Focused on. Since only a part of the parabolic surface is used, downsizing is possible. Further, since there is no obstructing sub-reflecting mirror or primary radiator in the central axis direction of the main reflecting mirror, there is a feature that a low side lobe can be achieved.
On the other hand, a Cassegrain antenna is an antenna in which a rotationally symmetric radio wave reflector is a main reflector, and a sub-reflector and a primary radiator are provided in the central axis direction perpendicular to the main reflector surface. Reflected by the mirror, the reflected wave is further reflected by the sub-reflecting mirror and focused on the primary radiator. Since the received radio wave can be caught on the entire main reflector surface, the reception efficiency is good.

―Primary radiator―
The primary radiator used in the present invention has a function of receiving a radio wave focused by the radio wave reflector and transmitting a transmission radio wave toward the radio wave reflector. The primary radiator is not particularly limited as long as it can suitably transmit and receive the use frequency of the transmission / reception radio wave band, and can be appropriately selected according to the purpose.

-Antenna holding member-
The antenna holding member includes a holding frame, a support column, a holding plate, and an attachment device. There is a function of holding the radio wave reflector and mounting it at an appropriate position and posture.

--Retention frame--
The holding frame has a function of holding the radio wave reflector. The structure of the holding frame is not particularly limited as long as it can hold the radio wave reflector, and can be appropriately selected according to the purpose, and may be a single structure or a combination of two or more. However, a single structure is preferable in terms of workability. For example, a single structure having a cylindrical shape at one end and a flange portion having the same shape as the flange portion of the radio wave reflector and having both ends opened can be used.

  The size of the holding frame is not particularly limited as long as it can be joined to the flange portion of the radio wave reflector, and can be appropriately selected according to the purpose. For example, since the rotary paraboloid portion of the radio wave reflector is inserted into the opening, the inner diameter of the opening is formed to be 2 to 5 mm larger than the outer diameter of the rotary paraboloid portion of the radio wave reflector. It is preferable.

  There is no restriction | limiting in particular as a material of the said holding frame, According to the objective, it can select suitably, For example, the board, pipe, etc. which consist of metal materials are mentioned. Examples of the metal material include aluminum, duralumin, iron, stainless steel, copper, and brass, and an aluminum plate that is lightweight and has high mechanical strength is preferable.

  The thickness of the holding frame is not particularly limited as long as it can hold light weight and mechanical strength, and can be appropriately selected according to the purpose. The thickness is selected according to the size and material of the radio wave reflector. For example, if the material is an aluminum plate and the diameter of the opening is about 1 m, 1 to 3 mm is preferable, 1.6 to 2.5 mm is more preferable, and 2 mm is most preferable.

  The method for manufacturing the holding frame is not particularly limited and may be appropriately selected depending on the intended purpose.For example, in the case of sheet metal, drawing, pressing, bending, punching, cold drawing, etc. Can be mentioned. In the case of the aluminum plate, press working, spatula drawing, bending and the like are preferable. In order to ensure durability, it is preferable to apply a cleaning treatment to the surface after processing.

―Post―
The support column has a function of connecting the holding frame and an installation tool for installing the antenna via the holding plate, and the antenna holding member can be reduced in weight by adopting a connection structure by the support column. it can.
The structure of the column is not particularly limited as long as it has mechanical strength, and can be appropriately selected according to the purpose. For example, it may be a single structure or a combination of two or more. For example, a structure in which at least three struts having a single structure are used, one end of the strut is joined to three positions on the rear surface of the flange portion of the holding frame at equal intervals, and the other end is joined to the holding plate is preferable.
The shape of the column is not particularly limited as long as it has mechanical strength, and can be appropriately selected according to the purpose. Examples thereof include a rod shape and a plate shape. From the viewpoint of workability, round bars, square bars and the like are preferable.
The size of the support column is not particularly limited as long as it has mechanical strength, and can be appropriately selected according to the purpose. For example, the thickness is 5 to 30 mm, and preferably 10 to 20 mm. . The length is preferably equal to or greater than the height of the protruding back surface of the radio wave reflector.
There is no restriction | limiting in particular as a material of the said support | pillar, According to the objective, it can select suitably, For example, a metal, a plastics, etc. are mentioned. Among these, a metal pipe material is preferable from the viewpoint of mechanical strength and weight reduction.

―Holding plate―
The holding plate is connected to one end of the support column and has a function as a connecting member so as to be united as an antenna holding member by being joined to the fixture.
There is no restriction | limiting in particular as a structure of the said holding | maintenance plate, According to the objective, it can select suitably, For example, the structure of combining independently or 2 or more may be sufficient. A single structure is preferable in terms of mechanical strength and workability. For example, the thing which escapes the protrusion part of the said electromagnetic wave reflector in the center part of a disk shaped board, and the through-hole for measuring weight reduction is mentioned.
The material of the holding plate is not particularly limited as long as it has mechanical strength, and can be appropriately selected according to the purpose. Examples thereof include metals and plastics. preferable. Examples of the metal include iron, aluminum, copper, brass, etc. Aluminum is preferable from the viewpoint of mechanical strength and weight reduction.
There is no restriction | limiting in particular as a magnitude | size of the said holding | maintenance plate, According to the objective, it can select suitably, For example, it has the external shape of 1/4 to 1/2 of the external shape of the said holding frame, and thickness is 2 ~ 5 mm is preferred.

―Mounting device―
The mounting fixture has a function of appropriately installing the antenna device at a desired place, and can be freely rotated in the horizontal and vertical directions and fixed in a desired posture in order to adjust the posture after installation. . The mechanism and structure of the mounting device are not particularly limited as long as they have mechanical strength to support the antenna device, weather resistance, and earthquake resistance, and can be appropriately selected according to the purpose.

-Assembly of antenna holding member-
The antenna holding member is joined by welding the holding frame, the support column, the holding plate, and the attachment device. First, one end of the column is welded to the back surface of the flange portion of the holding frame, and the other end of the column is welded to the holding plate. The welding is performed according to the number of the columns. Further, the holding plate is assembled by welding to the fixture.

-Assembly of radome, radio wave reflector and antenna holding member-
In the antenna device of the present invention, the flange portion of the radome, the flange portion of the radio wave reflector, and the flange portion of the holding frame are in contact with each other, and a coupling member is inserted into a through hole formed in each flange portion and fastened. And an integrated structure.

--Other parts--
Examples of other components include a waveguide, a cable, an LNA (low noise amplifier), and an LNB (low noise block down converter).

  Examples of the present invention will be described below, but the present invention is not limited to the following examples. In the embodiment of the present invention, a parabolic antenna device having a working frequency of 18 GHz and an effective antenna diameter of 75 cm is employed.

―Radome―
FIG. 1 is a perspective view showing a parabolic antenna device of the present invention. As shown in FIG. 1, the radome 1 is cylindrical, has a height of about 100 at the high part, and an inclination of about 50 mm at the low part, and the bottom surface is made of a spherical shape that is a vertical and horizontal object with a curvature radius of R1000 mm. . The inner diameter of the opening corresponds to the operating frequency and is approximately φ800 mm, the outer shape of the flange 1 a is 846 mm ± 5 mm, and the bottom is 3 mm thick. In addition, through holes for coupling are formed in the flange portion 1a evenly at six locations with a size of φ5 mm. The material was produced by injection molding using FRP made of epoxy containing glass cloth. The surface is painted with urethane.

−Radio wave absorber−
The radio wave absorber 4 has a lock shape made of vinylidene chloride-based synthetic fiber. The lock shape refers to a synthetic fiber or the like that is curled (crimped) into a spring shape, and these are covered and bonded with a binding material. Specifically, FP-1 manufactured by Mitsubishi Cable Industries, Ltd. was used. FP-1 has a density in the thickness direction of the lock shape, the density gradient type that becomes denser as the inside of the radio wave incident surface becomes rougher and goes into the inside. In order to improve the weather resistance, a conductive paint is applied. Yes.
With such a structure, an excellent return loss characteristic can be obtained over a wide frequency band.
The size of the FP-1 is 1000 mm × 1000 mm, and the thickness is 20 mm. The usable frequency band can correspond to 6 to 40 GHz, and a return loss of 20 dB or more can be obtained.

-Mounting the wave absorber on the radome-
The radio wave absorbers 2 and 2a of the present embodiment have a size of 50 mm × 100 mm at a position 5 mm from the end of the opening at an intermediate position where the height of the inner peripheral side surface of the radome 1 is inclined at about 70. And pasted so that the longitudinal direction was the circumferential direction. It stuck on the side facing this sticking position similarly.
Since it is attached at such a position, it does not hinder the passage of transmitted / received radio waves, has good weather resistance, and does not impair the appearance. The radio wave absorbers 2 and 2a effectively absorb the radio wave leaking outward from the radio wave reflector 4 by the radio wave absorber 2, and the side lobes are effectively reduced.

−Radio wave reflector−
As shown in FIG. 1, the radio wave reflector 4 is a radio wave reflector for a Cassegrain antenna for an 18 GHz band formed by a paraboloid of revolution and a flange portion 4a.
The radio wave reflector 4 was manufactured such that the effective reflection surface used as the radio wave reflection surface had an outer diameter of φ750 mm and the flange portion 4a had an outer diameter of φ846 ± mm. In the flange portion 4 a, six through holes for coupling are formed in a uniform manner at six locations with a size of φ5 mm corresponding to the through holes of the flange portion 1 a of the radome 1.
The radio wave reflector 4 was made by press working with a mold using a 2mm-thick 1100-type aluminum plate (A1100P-0) having good workability.

―Primary radiator―
In the present embodiment, a primary radiator for 18 GHz band having a function of receiving a radio wave focused by the radio wave reflector 2 and emitting a transmission radio wave toward the radio wave reflector 2 is used.

-Antenna holding member-
The antenna holding member 15 includes a holding frame 6, a support 7, a holding plate 8, and an attachment device 10. There is a function to hold the radio wave reflector 4 and equip it with an appropriate position and posture.

--Retention frame--
As shown in FIG. 1, the holding frame 6 has a cylindrical shape having a flange portion having the same shape as that of the flange portion 4 a of the radio wave reflector 4 at one end, and has a single structure with both ends opened.
The inner diameter of the opening of the holding frame 6 was φ800 mm, and the outer diameter of the flange portion 6a was φ846 ± mm. In the flange portion 6a, through holes for coupling are formed equally at six locations with a size of φ5 mm corresponding to the through holes of both the flange portion 1a of the radome 1 and the flange portion 4a of the radio wave reflector 4. .
The material of the holding frame 6 was manufactured by press working with a die using a 2mm-thick 1100-type aluminum plate (A1100P-0) having good workability.

―Post―
As shown in FIG. 1, the support | pillar 7 was cut | disconnected and produced by length 200mm using the aluminum pipe | tube (A1050-O) 20xt2. In this example, four struts 7 were used, so that four struts were made in the same shape.

―Holding plate―
As shown in FIG. 1, the holding plate 8 was manufactured using a turret punch press with an aluminum plate (A5052P-34) t3 having an outer diameter of 300 mm and an inner diameter of the through hole of 200 mm.

―Mounting device―
The mounting device 10 is formed in a box-shaped housing structure using an aluminum plate (A5052P-34) with a thickness of 3 mm, and can be freely rotated in the horizontal and vertical directions and fixed in a desired posture in order to adjust the posture. A rotation mechanism was formed so as to be able to.

-Assembly of antenna holding member-
The antenna holding member 15 is formed by arc welding the holding frame 6, the support 7, the holding plate 8, and the fixture 10.

-Assembly of radome, radio wave reflector and antenna holding member-
The antenna device 20 of the present embodiment is in contact with the flange portion 1a of the radome 1, the flange portion 4a of the radio wave reflector 4, and the flange portion 6a of the holding frame 6, and 5 mm in the through hole formed in each flange portion. Bolts were inserted, and the opposite side was fastened with a 5 mm washer and nut to form an integral structure.

-Parabolic antenna device-
The parabolic antenna device 20 of the present embodiment is provided with, for example, a waveguide, a cable, an LNA (low noise amplifier), an LNB (low noise block down converter), and the like as other components. Installed. Received after adjusting the attitude toward the destination of the used frequency band.
As shown in FIG. 2, the radiation directivity of the parabolic antenna device 20 of the present embodiment is different from the radiation directivity of the conventional parabolic antenna device shown in FIG. It can be seen that the directivity and the point of radio wave interference are remarkably improved by the decrease of 10 and several dBi in each range of 60 ° to 120 ° and the angle of −60 ° to −120 °.

  The parabolic antenna device of the present invention is suitable for a parabolic antenna device for communication equipment such as a relay line connecting between telephone stations, radar, satellite communication, radio astronomy, space research, wireless LAN, and satellite broadcasting (CS broadcasting, BS broadcasting, etc.). Can be used.

FIG. 1 is a perspective view showing a parabolic antenna device of the present invention. FIG. 2 is a chart showing the directivity of the parabolic antenna device of the present invention. FIG. 3 is a perspective view showing a conventional parabolic antenna device. FIG. 4 is a chart showing the directivity of a conventional parabolic antenna device.

Explanation of symbols

1 ····································· Radio wave absorber 4 ·············・ ・ ・ ・ ・ Primary radiator 6 ・ ・ ・ ・ ・ ・ ・ ・ Holding frame 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Still 8 ・ ・ ・ ・ ・ ・ ・ ・ Holding plate 10 ............ Mounting tool 15 ............ antenna holding member 20 ............ parabolic antenna device 101... Radio wave reflector 102 ······· Radio wave absorber 103 ··············································・ Primary radiator 106 ・ ・ ・ ・ ・ ・ ・ ・ ・ Holding frame 107 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Prop 108 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Holding plate 110 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mounting Appliance 115 ... Ante Holding member 120 ......... parabolic antenna device

Claims (3)

  A parabolic antenna device comprising at least a radome having a radio wave absorber on at least a part of an inner surface thereof, and a radio wave reflector coupled to the radome.   The parabolic antenna device according to claim 1, wherein the radio wave absorber is at least one of a plate shape and a sheet shape. The parabolic antenna device according to claim 1, wherein the radio wave absorber is made of a vinylidene chloride synthetic fiber.

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