JPS62230203A - Antenna system - Google Patents

Abstract

PURPOSE:To convert an elliptically botanized wave generated in a propagation line into a linearly polarized wave by constituting plural reflection mirrors of the antenna system so as to cancel the cross polarized wave component and inserting an elliptic waveguide between a horn and a circular feeding waveguide. CONSTITUTION:A radio wave fed from a group branching filter 2 of a tranemission system antenna system is converted into an elliptically polarized wave by the guide diameter change of the circularly feeding waveguide 4 and converted again into a linearly polarized wave by adjusting a circular waveguide 3. A direct wave 7 and a reflected wave 7' are received simultaneously by a reception system antenna system. Reflection mirrors 8,9 and 10 are constituted to cancel the cross polarized wave component generated on each reflection mirror. In adjusting an elliptic waveguide 3'' conneced between the horn 5' and the circular feeding waveguide 4', the circularly polarized wave is converted into the linearly polarized wave to obtain an excellent cross polarized identification characteristic.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a transmitting/receiving antenna device that faces each other at a predetermined distance, and that radio waves radiated from the transmitting antenna device have separation characteristics between two orthogonal polarized waves. The present invention relates to an antenna device system that allows reception without loss of signal.

[Conventional technology]

FIG. 4 shows a conventional antenna system installed oppositely on the propagation path (1), with +21. (2°) is a group demultiplexer that separates the radio waves and frequencies of the transmitting system and receiving system antenna device; 131. (It is a waveguide with an oval internal cross-sectional shape that can rotate around the three-piece tube m.Furthermore, (4) (41) is a circular feeding waveguide of the transmitting system and receiving system antenna device, +51. (5°) is the horn of the transmitting system and receiving system antenna device, and (61, () is the rotationally non-symmetrical reflecting mirror of the transmitting system and receiving system antenna device.

(Force, (7") is the direct wave and reflected wave propagating in the spatial propagation path. Conventionally, in such an antenna system.

In order to obtain a predetermined degree of polarization separation, that is, degree of cross-polarization discrimination, the transmitting system 2 and receiving 1G system antenna devices should be completely facing each other, and each group branching filter +21. (2') '& Cross polarized wave component Vx of vertically polarized waves and crossed polarized wave component H of horizontally polarized waves as seen by the receiving system antenna device by rotating by a predetermined angle alternately
The above group branching filter +21.
(Two? Oval waveguide fixed and further connected to the transmitting system and receiving system antenna device +33. (3')
By rotating by a predetermined angle, cross-polarized components generated due to pipe diameter distortion of the circular feeding waveguides (4) (4'') of the transmitting system and receiving system antenna devices were compensated for.

[Problem that the invention seeks to solve]

However, in this method, Vx, H
If the rotation angle of the group demultiplexer that maximizes the z discrimination is greatly deviated, a problem has arisen in that a predetermined cross-polarization discrimination cannot be obtained over a wide band. Generally, propagation path (1)
If the reflection coefficient at the reflection point above is small, as mentioned above, if the transmitting system and receiving system antenna devices are completely facing each other, a group splitter (21, The rotation angles at which the discrimination of Vx and Hx becomes maximum are almost the same, and good characteristics can be obtained.
If the a) component is not sufficiently smaller than the direct wave (7) component, that is, the reflected wave (7°) in the propagation path (1)
When the reflection coefficient at the reflection point of When a tilt occurs, the combination with the direct wave (7) results in a circularly polarized wave that is generally tilted from the horizontal or vertical.

moreover.

Since the reflector of the receiving antenna device is rotationally asymmetric, the direction of rotation of the elliptical polarization also differs depending on the difference in the transmission polarization.

Therefore, as shown in Figure 5, Vx, Hz
Group demultiplexer with maximum discrimination of +21, (2')
The angle of rotation changes, and the depth of the drop also becomes duller.

In the figure, the solid line is Hz, point l! i! is the case of Vx, and FIG. 5(a) shows the group branching filter (2) of the transmission system antenna device.
In the case of rotation, FIG. 5(1)) shows the cross-polarized wave discrimination characteristic as seen in the reception antenna system when the group branching filter (2'') of the reception antenna system is rotated.

In this case, 1 group splitter + 21. The setting angle of (2") is usually selected at the intersection point of Vx and Hz, or because Vx and Hz are in opposite phase at this angle, the same wave tube (?i
') 7al - It is not possible to improve both Vx and Hz even with rotation.

Also, if the setting angle of the two-group demultiplexer t2+ (2') is adjusted so that Vx and Hz are in the same phase region,
Vx and Hz are degraded to about 20 to 30 dB, and if this is to be compensated for, the deterioration of the VSWR characteristics due to the symsensitive wave tube (3'), which has a relatively large amount of compensation, cannot be ignored.

This invention was made to solve the above problems, and converts elliptical polarization into linear polarization.

The purpose of this invention is to obtain an antenna device having good cross-polarization discrimination characteristics.

[Means for solving problems]

The antenna device system according to the present invention is configured such that a plurality of reflecting mirrors of a transmitting or receiving antenna device cancel out cross-polarized components generated by each reflecting mirror, and further includes a horn and a circular feeding waveguide. A sympathetic wave tube was inserted between the two.

[Function] - The antenna device system according to the present invention is configured to cancel cross-polarized components generated by the nine reflecting mirrors, and is converted in the propagation path by a symsensitive wave tube connected to the feeding end of the antenna and horn. This converts circularly polarized waves into linearly polarized waves to obtain good cross-polarized wave discrimination characteristics.

[Example] Figure 1 shows an example of the present invention. + ('') is a tube that can be rotated around the axis of the tube connected to the feed end of the horn of the receiving system antenna device, and has an internal cross-sectional shape. It is a circular waveguide, and 181 and 191 are the first sub-reflector and the second sub-reflector consisting of rotating quadratic curved mirrors of the receiving system antenna device, and the mirror is the rotating parabolic mirror of the receiving system antenna device. This is the main reflecting mirror, and the reflecting mirrors +81. ,
(!I') , (4), (4'), +5), (
5'), +61. +7) and (7°) are similar to those shown in FIG.

The radio waves fed from the group splitter (2) of the transmission system antenna device are converted into elliptical polarized waves by the pipe diameter distortion of the two circular feeding waveguides (4), but the waveguides (3) By adjusting this, it is reconverted into a linearly polarized wave and is radiated to the propagation path ill via 9 reflecting mirrors + 61 g. If seven reflected waves occur on this propagation path (1) and the reflection coefficient at the reflection point is large, the receiving system antenna device will receive direct waves (7) and reflected waves (7).
71) are received at the same time, and the two reflected waves (71) have polarized waves at the time of reflection.

When combined with the direct wave (7), it becomes an elliptical polarized wave, and the axis of the elliptical polarized wave is tilted from the vertical or horizontal.

At this time, 2 reflections @+8. +9+, 4 is configured to cancel the cross-polarized components generated by each reflecting mirror, so it is equivalent to a rotationally symmetrical parabolic antenna with a very large focal length, that is, a plane reflecting mirror. The elliptical polarized wave maintains its shape and the reflection mirror +81. +93. an and horn (”)l
It reaches the group splitter (2') via the same wave tube (31), 9 circular feeds (waveguide (4°), and the same wave tube (5') Y).

However, the above-mentioned symsensitive waveguide (3 is the above-mentioned circular feed 4 waveguide (4
1) Adjustment distortion is applied to compensate for cross-polarized components generated due to pipe diameter distortion.

At this time, as shown in Fig. 2, the maximum value of the discrimination degree of Vx and Hz is because the arriving wave is an elliptical polarized wave.

The rotation angles of the group demultiplexer (2'') at which the Vx' and HxO discrimination degrees are maximized are almost the same, although they disappear quickly.

In the figure, the solid line indicates Hz, and the dotted line indicates Vx.

Next, the rotation angle of the 2-group splitter (2゛) was fixed at the maximum value of the discrimination degree of Vx and Hz, and the horns (5) and the circular feeding waveguide (
By adjusting the three equal-sensitivity wave tubes connected between the four " Note that in the above embodiment, the reflector 2 of the receiving antenna device
Although it is assumed that there are three sheets, any number of sheets other than one may be used.

〔Effect of the invention〕

As described above, according to the present invention, the feeding end of the horn is connected to the antenna consisting of a plurality of reflecting mirrors configured to cancel the cross-polarized components generated by the nine reflecting mirrors in the receiving system antenna device. By connecting the same wave tube, the elliptical polarization generated in the propagation path is converted to linear polarization, and it is possible to obtain good cross-polarization discrimination characteristics.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an antenna system according to an embodiment of the present invention, FIGS. 2 and 3 are diagrams showing crossed polarization discrimination characteristics, and FIG.
The figure shows a conventional antenna system, and Figure 5 shows the excitation angle characteristics of the splitter for transmission and reception.
] is the propagation path, +21. (2') is a group demultiplexer, t
ag, (5'), (3') bare sympathetic wave tube, (4
), (4°) is a circular feeding waveguide, +51. (5'
) is the horn, (61, (6'). al is the main reflection & ! (81y 19J are the first
Sub-reflector and g22 sub-reflector, (7) is a direct wave, (7
``) is a reflected wave 0. In Figure 9, the same or corresponding parts are indicated with the same reference numerals.

Claims (1)

[Claims] An antenna consisting of a horn as a primary radiator and one or more non-rotationally symmetrical reflectors, a circular feeding waveguide is connected to the feeding end of the horn, and the internal cross-sectional shape is oval. In a transmitting/receiving system antenna system, each of which is connected to a waveguide and a group branching filter that separates polarization and frequency faces each other at a predetermined distance from each other. The reflecting mirrors are configured to cancel out cross-polarized components generated by each reflecting mirror, and furthermore, there is a structure between the horn and the circular feeding waveguide that is rotatable around the tube axis and has an oval internal cross-sectional shape. An antenna device system characterized by inserting a waveguide and adjusting the elliptical polarization converted on the propagation path to reconvert into linear polarization.