JPS61214805A - microwave antenna device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] A primary radiator connected to a signal ground is covered with a parabolic reflector or an electromagnetic wrapper and a parallel metal strip, and this is covered with a frame insulated from the primary radiator. A microwave antenna device is disclosed in which the antenna is grounded so that low frequency electromagnetic interference waves are not coupled to the signal ground.

[Industrial application field]

The present invention relates to a microwave antenna device, particularly an antenna using a parabolic antenna, a Cassegrain antenna, or a radio wave lens, which is not affected by external electromagnetic interference waves.

In wireless equipment that transmits and receives digital signals, which have become widely used in recent years, received data may be input directly into a computer for data processing, so it is important to minimize code errors caused by noise, etc. is desired.

[Conventional technology and problems]

FIG. 4 shows an example of a wireless device using a conventional parabolic antenna.

In the figure, 1 represents the main body case of the wireless device, 2 represents the frame ground casing, 3 represents the primary radiator 34 that emits microwaves from the waveguide, which is a parabolic reflector, and 5 represents the radome that protects the antenna.

Generally, in electrical equipment, an internal conductor is shielded with an external conductor, and this is used as a signal ground SG. However, if external electromagnetic interference is coupled to this signal ground SG.

In equipment that requires a reduction in error rate, as it may cause equipment malfunction, a signal ground SG is also used.
is covered with a frame ground FC insulated from this 2
Double shielding is in place.

For example, in the case of a conventional wireless device as shown in FIG.
The wireless device main body case l is connected to the signal ground SG,
This is shielded by a frame ground casing 2, and the frame ground casing 2 is used as a frame ground FC. The feed hole of the primary radiator 3 is connected to the signal ground SG.
Therefore, the parabolic parabolic reflecting mirror 4 often becomes the frame ground FC.

However, in the antenna shown in Figure 4, the primary radiator 3, which serves as the signal ground SG, is electromagnetically exposed to the outside, so it is susceptible to external electromagnetic interference waves. There is a problem. In particular, recently, wireless devices are often placed in offices where data terminals are installed, rather than being placed outdoors, and one person may frequently approach or leave the device, so clothing, etc., may become electrostatically charged. There is a problem in that the static electricity is discharged and a relatively low frequency electromagnetic wave is coupled to the primary radiator 3 of the signal ground SG due to the spark, which may cause bit errors in data transmission and reception.

[Means for solving problems]

The present invention aims to solve the above-mentioned problems, and provides a means to avoid the influence of relatively low-frequency electromagnetic interference waves from the outside without affecting the microwaves radiated from the antenna. Therefore, in the microwave antenna device of the present invention, the electromagnetic wrapper made of the metal part of the reflector or the metal cover is connected to the frame ground FC, and the metal part of the reflector or the electromagnetic wrapper is provided with a thin parallel metal on the front surface. A frame ground F is provided so that this parallel metal plate has the same potential as the two reflecting mirrors or electromagnetic trumpets.
The configuration is such that it is connected to G.

[Effect]

In the case of the present invention, the primary radiator connected to the signal ground SG is shielded on the front side in the direction of microwave radiation by a metal strip, and on the rear side by a metal strip attached to a reflector or an electromagnetic trumpet. It becomes a shape.

The metal strip on the front does not interfere with linear polarization and allows microwaves to pass through, but at low enough frequencies,
The reason for being shielded by the metal strip is thought to be as follows. For example, a rectangular waveguide 3 as shown in FIG.
At 0, the 9 frequency is low, known as the cut-off frequency, and 1/2 of its wavelength λ is
If it becomes longer than the width a of 0, the wave will no longer propagate. In the case of the present invention, a thin parallel metal plate is considered to perform the same function as this waveguide. In other words, the diameter of the two reflecting mirrors, etc.

For example, if it is 30c+a, this is the waveguide width a
, and wavelengths of 60 cm or more are blocked. On the other hand, for microwaves having a frequency of 10'Hz or higher, for example, linear polarization is not hindered.

〔Example〕

FIG. 1 shows an example of a parabolic antenna device which is an embodiment of the present invention. In FIG. 1, numerals 1 to 5 correspond to those shown in FIG. 10 is an insulator that insulates the signal ground SG and frame ground FG; 11 is a thin parallel metal plate; 12 is a dielectric plate that connects the radome 5;
Represents what constitutes.

FIG. 1(a) is a front view of the parabolic reflector. FIG. 1(b) is a cross-sectional view taken along the line AA' shown in FIG. 1(a). In this embodiment, a parallel metal plate 11 as shown in FIG. 1(A) is attached to the radome 5. The parabolic reflector 4 is connected to the frame ground casing 2 to form a frame ground FC, and the metal plate 11 is also connected to the frame ground FC.

By being connected to the parabolic reflector 4, it becomes a frame ground FC.

The primary radiator 3 is connected to a signal ground SG having the same potential as the wireless device main body case l, and is insulated from the frame ground FC by an insulator 10.

The parallel metal plate 11 that is perpendicular to the direction of the electric field E of the microwave shown in FIG. It will not be done.

FIG. 1 is an example of a parabolic antenna device.

It is similarly applicable to Cassegrain antenna devices.

FIG. 2 shows an example of an antenna device using a radio wave lens, which is another embodiment of the present invention. In the figure.

20 represents a radio wave lens, and 21 represents an electromagnetic trumpet.

FIG. 2(a) is a front view of the radio lens 20 side, and FIG. 2(b) is a cross-sectional view taken along the line AA' in FIG. 2(a). The microwave radiated from the primary radiator 3 is converted into a plane wave by the radio lens 20,
Output.

In the case of this embodiment, the electromagnetic wrapper 21 is constituted by a metal cover in the shape of one cone or a square pyramid, and is connected to the frame ground casing 2 to form the frame ground FC. A radio wave lens 20 made of a thin parallel metal plate 11 is attached to the tip of this metal cover, and the metal plate 11 also serves as a frame ground FC. Therefore, no low frequency electromagnetic interference waves are induced into the primary radiator 3 of the signal ground SG which is insulated from this. That is, parallel metal plate 11
is connected to the frame ground FG, so it plays the role of the radio wave lens 20 and blocks low frequencies.

〔Effect of the invention〕

As explained above, according to the present invention, the signal ground S
The primary radiator of G is now covered by the outer metal body of frame ground FG.

For example, it becomes possible to prevent the influence of artificial noise caused by static electricity sparks from clothing, etc.

[Brief explanation of the drawing]

Fig. 1 is an example of a parabolic antenna device which is an embodiment of the present invention, Fig. 2 is an example of an antenna device using a radio wave lens which is another embodiment of the present invention, and Fig. 3 is a detail of the present invention. FIG. 4, which is a diagram for explaining the present invention, shows an example of a wireless device using a conventional parabolic antenna. In the figure, 1 is the main body case of the wireless device, 2 is the frame ground casing, 3 is the primary radiator 34 is a reflector, 5 is the radome, 1
1 is a metal plate, 12 is a dielectric plate, 20 is a radio wave lens, 21
represents an electromagnetic wrapper, SG represents a signal ground, and FC represents a frame ground. Patent Applicant: Fujitsu Ltd. Representative Patent Attorney Hiroshi Mori 1) Hiroshi (1 other person)

Claims (1)

[Claims] The microwave input end primary radiator (3) is connected to the signal ground, and the metal part of the parabolic reflector (4) or electromagnetic horn (21) is insulated from the primary radiator (3). and connected to the frame ground on a surface substantially perpendicular to the direction of microwave radiation on the front surface of the parabolic reflector (4) or the electromagnetic wrapper (21). A microwave antenna device provided with a parallel metal plate (11).