JPH07321542A - Primary radiator cover - Google Patents

Abstract

PURPOSE:To eliminate the water-proof processing of a circularly polarized wave/linearly polarized wave converter and to improve the cross polarization characteristic by covering an opening of the primary radiator of the converter with a foamed styrol and applying insert forming to the converter with a resin. CONSTITUTION:A front side of an opening 22 of a primary radiator 21 is covered with an expanded polystyrene 24 and a foamed resin cover 26 is molded by insert molding with a resin while leaving only a part of a connector 25 of a main body 20. A radio wave 23 from a satellite or the like is made incident onto a front side of the foamed resin cover 20 and received by the opening 22. The attenuation of a radio wave 23 made incident onto the foamed resin cover 26 is improved by selecting a foaming rate of the foamed resin cover 26 to be a specific value such as 60% thereby making the dielectric constant to be equal to that of air. Furthermore, since the reflection of a radio wave onto the foamed styrol 24 of the opening 22 of the primary radiator 21 and the foamed resin cover 26 is reduced, the reflected wave returned in the inside of the primary radiator 21 is reduced to improve the cross polarization protection ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite broadcasting receiving antenna, and more particularly to a converter for converting circular polarized waves into linear polarized waves.

[0002]

2. Description of the Related Art A receiving device for receiving radio waves from satellite broadcasts or the like focuses the radio waves on a parabolic antenna and receives them on a primary radiator in a circular polarization / linear polarization converter to convert the circular polarization to linear polarization. To a frequency of about 1 GHz and then sends it to the receiver. As shown in FIG. 2, a receiver having an integral structure including such a circular polarization / linear polarization converter and a frequency conversion converter has a main body 3 composed of a converter 1 and a primary radiator 2 made of plastic or the like. A cover A4 and a cover B5 made of synthetic resin are covered on the front and rear of the main body 3 so that both covers are fixed at the center of the main body. In this method, water leaks from the outside into the opening of the primary radiator 2 and the circuit board arranged inside the main body, so it is necessary to seal with an O-ring or a silicone adhesive. Further, there is a problem that when the radio waves focused by the parabolic antenna pass through the cover A4 on the front surface of the opening of the primary radiator 2 and enter the primary radiator 2, loss occurs.

A circularly polarized wave 8 incident on the primary radiator 2
As shown in FIG. 3, a 90 degree phase shifter 10 provided inside the circular waveguide 9 delays the phase of the electric field component of the circularly polarized wave 8 parallel to the phase shifter 10 by 90 degrees. By the first
The electromagnetic wave of the first linearly polarized wave 11 which is converted into the linearly polarized wave 11 and converted by the rectangular waveguide provided on the end surface of the circular waveguide 9 is input to the preamplifier.

On the other hand, a circularly polarized wave 12 having a reverse rotation different from the circularly polarized wave 8 is also incident on the primary radiator 2 as noise, and when passing through the 90 ° phase shifter 10, the first linearly polarized wave is generated. 11
Is converted into the second linearly polarized wave 13 in the direction orthogonal to. The rectangular waveguide takes out only the first linearly polarized wave 11, and the second linearly polarized wave is reflected by the end surface of the circular waveguide 9 and passes through the 90-degree phase shifter 10 again, 90 degree phase shifter 10
By re-delaying the phase by 90 degrees, the circularly polarized wave 12 having the reverse rotation becomes the circularly polarized wave 7 having the same rotation as the right circular polarization 8, and as shown in FIG. 5, the cover of the opening 6 of the primary radiator 2 is covered. The light is reflected by A4 and goes to the 90-degree phase shifter 18 of the circular waveguide 17.
This is a noise component different from the intended received signal, but since the direction of rotation is the same as that of the circularly polarized wave 8, it is extracted by the rectangular waveguide and is input to the preamplifier. The wave protection ratio is deteriorated, and the voltage standing ratio is deteriorated due to the presence of the reflected wave.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. It eliminates the waterproof treatment of the circular polarization / linear polarization converter and improves the cross polarization characteristics. The purpose is to

[0006]

In order to solve the above-mentioned problems, according to the present invention, the opening of the horn-shaped primary radiator of the circular polarization / linear polarization converter is covered with styrofoam, and the circular polarization / linear It is intended to provide a primary radiator cover characterized in that a polarization converter is insert-molded with resin.

[0007]

According to the above construction, the opening of the horn-shaped primary radiator of the circular polarization / linear polarization converter is covered with styrofoam, and the circular polarization / linear polarization converter is integrated by resin insert molding. The resin is foamed and molded. as a result,
The circular polarization / linear polarization converter is hermetically sealed and covered with foamed resin, has a waterproof structure, and can improve cross polarization characteristics.

[0008]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. As shown in FIG. 1, 20 is a main body, which is a primary radiator 21, a phase shifter, a circular waveguide, a slot, a preamplifier,
It is composed of a converter and a connector. An opening 22 is provided at one end of the primary radiator 21, and a radio wave 23 from a satellite or the like is focused by a parabolic antenna and enters the opening 22. A styrofoam 24 is inserted into the front surface of the opening 22 and prevents resin from entering inside during insert molding. Reference numeral 25 denotes a connector, which is a connection terminal for outputting the reception signal converted to a predetermined frequency by the main body 20 to the outside. Reference numeral 26 denotes a foamed resin cover, which is, for example, a styrene material, is insert-molded by leaving only the connector 25 portion of the main body 20, and the resin is foam-molded.

In the above structure, a radio wave 23 from a satellite or the like is used.
Enters from the front surface of the foamed resin cover 26 and is taken into the opening 22. By molding the foaming rate of the foamed resin cover 26 to a predetermined value, for example, 60%, the dielectric constant becomes substantially equal to that of air, and the attenuation when the radio wave 23 enters the foamed resin cover 26 is greatly improved. . Further, as shown in FIG. 3 and FIG. 4, the reversely polarized circular polarized wave 12 passes through the 90-degree phase shifter 10 to be converted into the second linear polarized wave 13, and is reflected by the end surface of the circular waveguide 9. By passing through the 90-degree phase shifter 10 again and delaying the phase by 90 degrees by the 90-degree phase shifter 10 again, the circular polarization 12 of the reverse rotation becomes a circular polarization of the same rotation as the right circular polarization 8, and the aperture is opened. Head to the club. However, as shown in FIG. 1, since the polystyrene foam 24 and the foamed resin cover 26 in the opening 22 of the primary radiator 21 are less reflected, the reflected waves returned to the inside of the primary radiator 21 are reduced and the cross-polarized waves are reduced. The protection ratio is improved.

[0010]

As described above, in the present invention, since the circular polarization / linear polarization converter is molded with foamed resin to have a closed structure, conventionally, the opening of the primary radiator and the circuit board are waterproof. It was necessary to seal it using an O-ring or a silicon adhesive, but this is no longer necessary, and the loss when the radio wave focused by the parabolic antenna passes through the cover A and enters the primary radiator, and This has the advantage that the degree to which the left-handed polarized wave reflected and returned at the inner part of the primary radiator 2 is reflected again by the cover and returned to the inside is improved, and the cross polarization protection ratio is improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a primary radiator cover of the present invention.

FIG. 2 is a front view of a conventional primary radiator cover.

FIG. 3 is an operation conceptual diagram of a conventional primary radiator cover.

FIG. 4 is a conceptual diagram of the operation of a conventional primary radiator cover.

FIG. 5 is a partial cross-sectional view of a conventional primary radiator cover.

[Explanation of symbols]

 20 Main body 21 Primary radiator 22 Opening 23 Radio wave 24 Styrofoam 25 Connector 26 Foam resin cover

Claims (3)

[Claims] 1. A circularly polarized wave / linearly polarized wave converter, the opening of a horn-shaped primary radiator is covered with polystyrene foam, and the circularly polarized wave / linearly polarized wave converter is insert-molded with resin. Primary radiator cover to do. 2. The primary radiator cover according to claim 1, wherein the resin is foamed in the insert molding. 3. The primary radiator cover according to claim 1, wherein the resin is foamed at a foaming rate of about 60%.