JPH05110303A - Circularly polarized wave primary radiator - Google Patents

Abstract

PURPOSE:To obtain the circularly polarized wave primary radiator employed for an antenna used for the transmission/reception of a radio wave in a microwave band in which a desired cross polarized wave identificatin is easily obtained with high precision. CONSTITUTION:An axis ratio compensation disk (water-proof cap) 4 is placed on a face orthogonal in the propagation direction of a circularly polarized wave inputted/outputted to/from circularly polarized wave linearly polarized wave converters 2, 3 of the circularly polarized wave primary radiator, and the disk 4 is formed around the axis of the circularly polarized wave linearly polarized wave converters in the face in a way of the rotating position is made adjustable, and a projection stripe 5 or a recessed groove is formed in the radial direction on the face. The axis ratio is compensated by making the direction of an elliptic radio wave and the ellipse ratio of the radio wave in the axis ratio compensation disk coincident with the direction of an elliptic radio wave and the ellipse ratio of the radio wave of the elliptic polarized wave and linearly polarized wave converter as the circularly polarized wave linearly polarized wave converter with the excellent cross polarized wave identification.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primary radiator of a circularly polarized wave antenna used for transmitting and receiving in a microwave band, and more particularly to a primary radiator having an improved cross polarization characteristic of the circularly polarized wave antenna.

[0002]

2. Description of the Related Art Conventionally, a circular polarization linear polarization converter for converting a circular polarization and a linear polarization is used as a primary radiator of a circular polarization antenna used for transmitting and receiving in a microwave band. It is provided. FIG. 9 is a schematic perspective view showing an example thereof, and has a structure in which a dielectric plate 3 is axially arranged inside a waveguide 2 provided continuously to a circular horn 1. In this configuration, for example, the circularly polarized wave input from the horn 1 is transmitted to the dielectric plate 3 because the propagation speed of the radio wave in the dielectric plate 3 in the waveguide 2 is slower than the propagation speed in the air. The parallel electric field component is delayed by 90 ° in phase with respect to the component perpendicular to the dielectric plate 3, and is converted into a linear polarized wave.

As another structure, as shown in FIG.
A plurality of screws 3A are projected into the waveguide 2 and the screws 3
A controls the wavelength inside the waveguide 2 in a specific direction,
There is also one in which a 90 ° phase difference is provided between orthogonal electric field components.

[0004]

In such a conventional primary radiator, since the circular polarization linear polarization converter provided in the waveguide has a fixed structure, it has a certain degree in the entire use band. Designed to obtain cross polarization discrimination. However, there is a problem that it is difficult to obtain a cross polarization discrimination degree as designed due to variations in manufacturing the dielectric plate and the waveguide.

Further, the communication interference due to the cross polarization component does not always occur in the entire use band. Therefore, when particularly good cross polarization discrimination is required at a specific frequency within the used band, the above-mentioned conventional primary radiator has a fixed structure, and therefore sufficient cross polarization discrimination is achieved. Will not be obtained. The purpose of the present invention is to
It is an object of the present invention to provide a circularly polarized primary radiator that can easily obtain a desired cross polarization discrimination degree with high accuracy.

[0006]

A circularly polarized primary radiator according to the present invention is a dielectric member positioned on a plane orthogonal to the propagation direction of circularly polarized waves input to and output from a circularly polarized linear polarization converter. The axial ratio compensating plate is composed of the axial ratio compensating plate, the rotational position of which can be adjusted around the axis of the circular polarization linear polarization converter in its plane, and the axial direction compensating plate has a radial direction. A ridge or a groove is formed toward. For example, the axial ratio compensator is composed of a waterproof cover attached to a horn that is continuous with a circular polarization linear polarization converter. Alternatively, the axial ratio compensating plate is screwed into a thread formed on a ring-shaped support attached to the circular polarization linear polarization converter, and is configured to rotate using the thread.

[0007]

According to the present invention, by matching the elliptical direction and ellipticity of the radio wave in the axial ratio compensating plate with the elliptic direction and ellipticity of the elliptical polarization linear polarization converter, the axial ratio is compensated positive. It can be configured as a circular polarization linear polarization converter having a circular, that is, good cross polarization discrimination.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of an embodiment of the present invention.
It has a circular horn 1 and a continuous waveguide 2
A circular polarization linear polarization conversion for converting a circular polarization input from the horn 1 into a linear polarization by extending a dielectric plate 3 in the waveguide 2 in the axial direction at a required angle in the same manner as in the conventional case. Vessel is constructed.
On the other hand, a circular waterproof cap 4 as an axial ratio compensating plate is attached to the horn 1, as shown in side views and front views in FIGS. 2 (a) and 2 (b), respectively. A diametrical ridge 5 is formed on the surface of 4.

The waterproof cap 4 is made of a dielectric material having a relative dielectric constant other than 1, and the protrusion 5 is integrally formed.
For example, it is selected from commonly used plastic materials in consideration of radio wave passage loss, processability, and weather resistance. The width of the ridge 5 is about 1/10 wavelength, and the height thereof is determined by the relative permittivity of the material and the ellipticity of the circular polarization linear polarization converter. Further, a claw 6 projecting in the inner diameter direction is provided at the opening edge portion of the waterproof cap 4, and when the waterproof cap is attached to the horn 1, a circumferential groove provided at the opening peripheral edge portion of the horn 1. 7 to prevent the waterproof cap 4 from falling off, and at the same time enhance the liquid tightness of the peripheral portion of the waterproof cap 4.

According to this structure, when the incoming circularly polarized radio wave passes through the waterproof cap 4, the ridge 5 provided on the waterproof cap 4 causes the ridge 5 among the electric field components of the circular polarized wave.
Since the amount of phase delay in the portion parallel to is larger than the component orthogonal to this, circular polarization is converted into elliptical polarization. Therefore, even if the circular polarization linear polarization converter configured in the waveguide 2 actually functions as an elliptical polarization linear polarization converter due to manufacturing errors or the like, the waterproof cap 4
If the elliptical direction and ellipticity of the radio wave that has become elliptically polarized in, and the elliptic direction and ellipticity of this elliptical polarization linear polarization converter match, the total of the perfect circle of which the axial ratio is compensated, In other words, it is configured as a circular polarization linear polarization converter with good cross polarization discrimination.

It is necessary to change the height of the ridge 5 and the angle with respect to the dielectric plate 3 in order to match the elliptic direction and the ellipticity of the ridge 5 and the circular polarization linear polarization converter. , In the case of an ellipse that is approximately close to a perfect circle, it is sufficient to change the angle. Further, since the above-mentioned manufacturing error and the like are generally large between manufacturing lots, the angle formed by the ridge 5 and the dielectric plate may be determined for each manufacturing lot.

3 to 5 are perspective views showing modifications of the waterproof cap according to the present invention. In the embodiment shown in FIG. 3, the protrusion 5A is provided on the inner surface of the waterproof cap 4.
Further, in the example of FIG. 4, the concave groove 8 is formed instead of the protrusion.
Further, in the example of FIG. 5, the concave groove 8A is formed by a gentle curved surface. With any of these waterproof caps, by adjusting the height, depth, and angle of the ridges and grooves, it can be used as a circular polarization linear polarization converter that actually functions as an elliptical polarization linear polarization converter. Together, they can be configured as a circular polarization linear polarization converter of a perfect circle.

FIG. 6 shows another embodiment of the present invention.
The same parts as those in the above embodiment are designated by the same reference numerals. In this embodiment, as shown in the side view and the front view in FIGS. 7A and 7B, a circular ring-shaped support 9 is attached to the opening of the horn 1 and formed on the inner surface of the support 9. A circular axial ratio compensating plate 10 is screwed onto the thread 9a. The axial ratio compensating plate 10 is made of a material such as plastic having a relative dielectric constant other than 1 as in the waterproof cap of the above-mentioned embodiment, and the surface thereof is also provided with a ridge 11 in the diametrical direction. The width of the protrusion 11 is about 1/10 wavelength.
Further, the support 9 is provided with a circumferential claw 12 in the inner opening, and the claw 12 is fitted into the circumferential groove 7 provided in the peripheral edge of the opening of the horn 1.

Also in this structure, when the incoming circularly polarized radio wave passes through the axial ratio compensating plate 10, the circularly polarized wave is converted into the elliptically polarized wave by the ridge 11. Therefore, the waveguide 2
By matching the elliptical direction and ellipticity of the circular polarization linear polarization converter configured as described above with the elliptic direction and ellipticity of the axial ratio compensating plate 10, a perfect circle in which the axial ratio is compensated, that is, cross polarization discrimination. It can be configured as a circular polarization linear polarization converter with good degree. At this time, the axial ratio compensating plate 10 is rotated with respect to the support 9 using the screw thread 9a, so that the ridge 11
It is possible to change the angle of.

FIG. 8 shows a modification of the axial ratio compensating plate 10, in which a concave groove 13 is formed instead of the ridge. It goes without saying that the same effect can be obtained by forming the groove 13 in this way.

In each of the above embodiments, an adhesive may be used instead of the claws provided on the waterproof cap or the support to integrally fix them to the horn. However, in this case, it is important to fix the waterproof cap after adjusting the angle of the ridge. Further, although the above description is for the case where the primary radiator is receiving, it goes without saying that it is also valid for transmitting.

[0017]

As described above, according to the present invention, since the axial ratio compensating plate which is attached to the circular polarization linear polarization converter and which is rotatable is provided with the ridge or the groove, the axial ratio is reduced. By matching the elliptical direction and ellipticity of the radio wave in the compensator with the elliptic direction and ellipticity of the elliptical polarization linear polarization converter, the perfect circle of which the axial ratio is compensated, that is, the cross polarization discrimination is good. It can be configured as a circular polarization linear polarization converter, which can compensate for cross polarization discrimination. Further, since the structure is simple, it can be applied to an existing primary radiator to improve the cross polarization characteristics easily and inexpensively.

[Brief description of drawings]

FIG. 1 is an overall perspective view of an embodiment of the present invention.

2 shows a waterproof cap, (a) is a side view, (b)
Is a front view.

FIG. 3 shows a modified example of the waterproof cap, in which (a) is a side view and (b) is a front view.

FIG. 4 shows another modified example of the waterproof cap, in which (a) is a side view and (b) is a front view.

FIG. 5 is a perspective view of still another modified example of the waterproof cap.

FIG. 6 is an overall perspective view of another embodiment of the present invention.

FIG. 7 shows an axial ratio compensating plate and a support, (a) is a side view and (b) is a front view.

FIG. 8 shows a modified example of the axial ratio compensation plate and the support,
(A) is a side view and (b) is a front view.

FIG. 9 is a perspective view of a conventional primary radiator.

FIG. 10 is a perspective view of another example of a conventional circular polarization linear polarization converter.

[Explanation of symbols]

 1 circular horn 2 waveguide 3 dielectric plate 4 waterproof cap 5 ridge 8 groove 9 support 10 axial ratio compensator 11 ridge 13 groove

Claims (3)

[Claims] 1. A primary radiator having a circular polarization linear polarization converter, wherein a dielectric positioned on a plane orthogonal to a propagation direction of circular polarization input to and output from the circular polarization linear polarization converter. It has an axial ratio compensating plate consisting of a body, and this axial ratio compensating plate is configured so that the rotational position can be adjusted around the axis of the circular polarization linear polarization converter in its plane, and the axial ratio compensating plate is A circularly polarized primary radiator having a ridge or a groove formed in a direction. 2. The circularly polarized primary radiator according to claim 1, wherein the axial ratio compensator is composed of a waterproof cover attached to a horn connected to the circularly polarized linearly polarized wave converter. 3. The axial ratio compensating plate is screwed to a thread formed on a ring-shaped support attached to a circular polarization linear polarization converter, and is rotated using the thread. The circularly polarized primary radiator according to claim 1, which is configured.