JPS5825702A - Parabolic antenna device - Google Patents

Abstract

PURPOSE:To obtain a high aperture area efficiency with a determined aperture area, by arranging a parabolic reflector a prescribed length apart from the aperture end face of an aperture waveguide part so as to face to a primary radiator provided with a flange. CONSTITUTION:A primary radiator 2 where a waveguide 5 is connected through a connecting part 6 is arranged in the focus position of the parabolic reflective face of a parabolic reflector 1 and faces to the parabolic reflector 1. This primary radiator 2 forms an electromagnetic horn and consists of an aperture round waveguide part 3 and a discoidal flange part 4 which is arranged on the outside circumference of the aperture round waveguide part 3 and in a position distant from an aperture end face 3' of this part 3. The diameter of the flange part 4 and the distance of the flange part 4 from the aperture end face 3' of the aperture round waveguide part 3 are changed to control the directivity of the primary radiator 2, and thus, the aperture area efficiency is set as high as possible with the parabolic reflector 1 having a determined diameter.

Description

[Detailed Description of the Invention] The present invention comprises a primary radiator and a parabolic reflector (parabolic reflector).
The present invention relates to a parabolic antenna device configured by combining the above, and particularly relates to a parabolic antenna device that is equipped with an improved primary radiator and has increased aperture efficiency.

A parabolic antenna is a typical antenna used for transmitting and receiving microwave signals.

A parabolic antenna generally consists of a parabolic reflector that reflects transmitted or received microwave radio waves with a parabolic surface, and a parabolic reflector that is placed at the focal point of the parabolic reflecting surface of the reflector to reflect the transmitted microwave radio waves parabolically. The primary radiator is configured in combination with a primary radiator that radiates toward the receiver or receives received microwave radio waves reflected by a parabolic reflector.

In recent years, satellite broadcasting systems that launch artificial satellites and use them to transmit microwave broadcast waves in the SHF band and receive them over a wide area are heading toward the stage of practical use. In the system, for example, each house in the reception area is equipped with a relatively small parabolic antenna to receive microwave radio waves from an artificial satellite. A relatively small parabolic antenna used for such a purpose has a small diameter parabolic reflector, so it is extremely important to increase its gain.

Generally, the gain G of a parabolic antenna can be expressed by the following equation. G=g ・ (π・ri)2, where λ is the wavelength of the transmitted and received microwave radio waves, D is the diameter of the aperture, that is, the diameter of the parabolic reflector, and gp is the aperture. Efficiency, simply put, is the ratio of effective area to geometric aperture area.

As is clear from the above equation, in order to increase the gain when the diameter of the parabolic reflector is determined, it is necessary to improve the aperture efficiency gp. Normally, a small electromagnetic pawn using a circular or rectangular waveguide is used as the primary radiator in a relatively small parabolic antenna, but the primary radiator composed of a conventional electromagnetic hole and the parabolic In combination with a reflector, the aperture efficiency Hp is about 30 to 6θ, and it cannot be said that a high aperture efficiency is achieved.

By the way, the aperture efficiency gp in a parabolic antenna is determined by the aperture angle of the parabolic reflector (the position of the -order radiator, i.e.,
The angle at which the center and periphery of the reflective surface are viewed from the focal point of the reflective surface is a function of F and the directivity d(f) of the primary radiator, where the vertical axis is the aperture efficiency g, and the horizontal axis is the aperture. Taking the angle V, the directivity d(φ) of the −order radiator.

When expressed as a parameter, it becomes as shown in FIG. Here, curves A, B, and C indicate that the directivity d (ψ°) of the -order radiator is a%b and C (however, a (b
Aperture surface efficiency g for the aperture angle in case (c)
It shows the change in p. From this, when the diameter of the parabolic reflector is determined and the aperture angle V is determined to a predetermined value, the aperture efficiency can be maximized under the predetermined value of the aperture angle W. It is understood that in order to make it high, the directivity d(ψ) of the -order radiator can be controlled. Conventionally proposed means for controlling the directivity of the primary radiator include using a multi-mode electromagnetic horn or a hybrid mode electromagnetic horn as the -order radiator, but these special electromagnetic horns require a design However, it is not suitable for use in combination with small-diameter parabolic reflectors.

In view of these points, the present invention provides a primary radiator with a simple structure and a modified base whose directivity can be controlled, thereby achieving high aperture efficiency under a predetermined aperture angle. Hereinafter, embodiments of the present invention will be described with reference to FIG. 2 and subsequent figures of the drawings.

FIG. 1 is a schematic side view showing an example of a parabolic antenna device according to the present invention. In the figure, l is a parabolic reflector with a parabolic reflecting surface, and ko is a parabolic reflector/
It is a primary radiator placed at the focal point of the parabolic reflecting surface facing the radiator. This second-order radiator includes, for example, an open circular waveguide section 3 and a circle disposed on the outer periphery of the open circular waveguide section 3 at a position away from its open end surface 3', forming an electromagnetic horn. It consists of a plate-shaped flange/ji part. and,
- A waveguide S for supplying transmitted microwave radio waves to the primary radiator or for guiding received microwave radio waves from the primary radiator is connected to the secondary radiator via a coupling part 6. has been done.

FIG. 3 is an enlarged view of the above-mentioned primary radiator, with FIG. 3A being a front view and FIG. 3B being a side view. Here, the open circular waveguide section 3 has an inner diameter R, and a connecting section 7 is formed at the end opposite to the open end surface 3'.

Open circular waveguide section 3 on the outer periphery of this open circular waveguide section 3
A disc-shaped flange portion is disposed at a distance from the opening end surface 3' of the opening end surface 3', and the diameter of this 7279 portion is F.

In one embodiment of the present invention configured as described above,
The microwave radio waves supplied from the waveguide S to the primary radiator are radiated from the -order radiator toward the parabolic reflector L, reflected by the parabolic reflector L, and transmitted to the outside in the form of a beam. In addition, microwave radio waves that reach the parabolic reflector l from the outside are reflected by the parabolic reflector l,
-It is like a normal parabolic antenna in that it is received by the secondary radiator and guided out by the waveguide S, but
Here, the diameter F of the disc-shaped flange part DA arranged in the open circular waveguide section 3 constituting the -order radiator and the distance from the open end surface 3' of the open circular waveguide section 3 By changing the angle, the directivity of the -order radiator can be controlled. For example, the fundamental mode of a circular waveguide (
TE//), the inner diameter R of the open circular waveguide section 3 is set constant, for example, /9 mm, and the open circular waveguide section 3
When the distance from the opening end surface 3' of the disc-shaped flange part tii to the disc-shaped flange part tii is kept constant and the diameter F of the disc-shaped seven flange parts is varied, the radiation from the -order radiator ko is Changes in the relative level 1 of the microwave radio waves with respect to the level on the central axis of the primary radiator in the electric plane-E plane and the magnetic plane/H plane were as shown in Figure A. Here, the vertical axis is the cane relative level l, and the horizontal axis is the electric surface/E surface and the magnetic surface/H
The line connecting the position in each plane of the surface and the primary radiator K is the angle θ that the line makes with the central axis of the primary radiator K, and the solid line curve 11, the broken line curve 12, and the dashed-dotted line curve 13 are as follows: The diameter F of the disc-shaped 7/J part is 29 mm, respectively.
m m and &2. ! This is the case for rmrn. From this, it can be seen that when the diameter F of the seven disc-shaped flange portions changes, the angle θ at which the same value of relative level l is obtained changes, that is,
- It can be seen that the directivity of the second radiator changes. especially,
This is noticeable in the E plane. Similarly, when the -order radiator is excited in the fundamental mode (TI/t) of the circular waveguide, the inside @R of the aperture circular waveguide section 3 is set constant, for example, 79 mm, and the circular waveguide The opening circular waveguide section 3 is formed by keeping the diameter F of the shaped flange constant, for example, somrp.
When the distance from the opening end surface 3' to the disc-shaped flange part DA is changed, the electric surface, E surface, and magnetic surface, H, of the microwave radio waves radiated from the -order radiator. Relative level l of the primary radiator in the plane to the level on the central axis
The changes were as shown in Figure q, B. Here again, the vertical axis is the relative level l, and the horizontal axis is the line connecting the primary radiator 2 and the position in each of the electric plane/E plane and the magnetic plane/H plane. The angle θ formed with the central axis is the solid line curve "/z, the broken line curve 1', and the dashed-dotted line curve 1/3, respectively.
The distance from the disc-shaped flange part i4 is Omm, 4m
m and /2. ! ;mm This is the case. From this, the angle θ that gives the same value of relative level 1 as the distance changes
It can be seen that this changes, that is, the directivity of the -order radiator changes. In this case as well, this is particularly noticeable on the E plane.

As described above, in the embodiment of the present invention having the primary radiator as shown in the third section, the diameter F and the distance of the disc-shaped flange portion DA are changed.
Since the directivity of this -order radiator can be controlled, the directivity of this -order radiator can be set to make the aperture efficiency as high as possible under a parabolic reflector with a predetermined diameter. be able to. In the experimental results, the diameter t! In the case of rOmm parabolic reflector, /2GHz microwave radio wave,
The aperture efficiency could be set to about 70-.

In the above embodiment, the -order radiator 2 is composed of an open circular waveguide section 3 and a disc-shaped 7279 section. It can also be configured by a combination of a rectangular plate-like seven flange portions. Figures A and B show another example of the primary radiator according to the present invention, which is constructed of such a rectangular member, and this row extends from the opening end face j' of the opening rectangular waveguide section and its outer periphery. In this case, the vertical and horizontal dimensions of the rectangular plate-shaped flange parts and the opening width of the rectangular plate-shaped flange parts are also determined. Similar to the example shown in FIG. 3, the directivity of the -order radiator can be controlled by changing the distance from the end face to the rectangular plate 79 part 9.

As explained above, with the parabolic antenna device according to the present invention, the directivity of the second-order radiator can be easily controlled with a simple configuration. The aperture efficiency of all the apertures can be made as high as possible, and as a result, a large gain can be easily obtained. In particular, the parabolic antenna device according to the fourth aspect of the present invention exhibits remarkable effects when configured using a small-diameter parabolic reflector, and is suitable for use as a relatively small parabolic antenna device.

In addition, in the parabolic antenna device according to the present invention, the shape of the 72 part that constitutes the primary radiator together with the aperture waveguide part is not limited to the above-mentioned example, and various shapes may be used as appropriate. 1.

[Brief explanation of the drawing]

The first part is a diagram used to explain the aperture efficiency of a parabolic antenna device, FIG. 2 is a schematic side view showing an example of a parabolic antenna device according to the present invention, and FIGS. 3 A and B are diagrams used to explain the aperture efficiency of a parabolic antenna device. A front view and a side view showing an example of a primary radiator used in the antenna device, and FIGS. FIG. 2 is a front view and a side view showing another primary radiator used in the parabolic antenna device according to the present invention. In the figure, l is a parabolic reflector, 2 is a primary radiator, 3 and g
is an open waveguide section, 3' and g' are open end faces, and q and 9 are 7279 sections. 111Figure 2Figure 3Figure 4A (L・-IllusionFigure 5A B

Claims (1)

[Claims] an aperture waveguide portion and a 7 ridge 7 disposed on the outer periphery of the aperture waveguide portion at a predetermined distance from the aperture end face of the aperture waveguide portion;
9. A parabolic antenna device configured to include a primary radiator consisting of 9 parts, and a parabolic reflector arranged opposite to the secondary radiator.