JPH0149201B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an improvement in polarization demultiplexers used in microwave bands and millimeter wave bands. This relates to a polarization demultiplexer that demultiplexes waves in the same axial direction.

[Prior art]

Conventionally, such a polarization splitter is composed of a circular main waveguide 1, an orthogonal sub-waveguide 2, a coaxial sub-waveguide 3, a coupling window 4, and a shorting rod 5, as shown in FIG. Something was warm. Another conventional example includes a circular main waveguide 1, two orthogonal sub waveguides 2a and 2b, a coupling window 4, and a shorting bar 5, as shown in FIG.

In any polarization splitter, at least one sub-waveguide must be arranged perpendicular to the main waveguide axis, which has the disadvantage that the cross-sectional size of the polarization splitter becomes large.

In particular, in a multi-beam antenna, a plurality of horn antennas 6 are arranged side by side as shown in FIG. There is a need. By the way, in the conventional polarization splitter, since the sub-waveguide is configured to be orthogonal to the main waveguide, this sub-waveguide has a drawback that it interferes with the adjacent splitter 7.

Furthermore, when trying to avoid interference, the array position of the horn antenna 6 is restricted, resulting in drawbacks such as the inability to radiate a beam in a desired direction.

[Summary of the invention]

This invention was made with the aim of improving such drawbacks, and includes a circularly polarized wave generator that converts linearly polarized waves into circularly polarized waves in space, and two circularly polarized waves, right-handed and left-handed, in the direction of propagation of radio waves. By configuring it in combination with a bulkhead polarizer that separates into two linearly polarized waves,
The present invention proposes a polarization splitter that can easily separate two mutually orthogonal linearly polarized waves and avoid interference with adjacent splitters.

[Embodiments of the invention]

First, the operating principle of this invention will be briefly explained. By using two circularly polarized wave generators, one circularly polarized wave generator converts linearly polarized waves into right-handed or left-handed circularly polarized waves, and the other circularly polarized wave generator converts them into right-handed or left-handed circularly polarized waves. Convert left-handed circularly polarized waves to linearly polarized waves. Therefore, one circularly polarized wave generator, that is, the side that converts circularly polarized waves into linearly polarized waves, separates right-handed or left-handed circularly polarized waves into linearly polarized waves in the same direction as the traveling direction of the circularly polarized waves. If possible, two mutually orthogonal linearly polarized waves can be split in the same direction.

In this invention, the two circularly polarized wave generators include a strip line type circularly polarized wave generator such as a meander-line or grid type that converts linearly polarized waves into circularly polarized waves in space; and the cross section of a square waveguide is 2 with equal area
A bulkhead polarizer is used, which has a tapered metal plate that is divided into two rectangular cross sections, and separates two circularly polarized waves, right-handed and left-handed, into the two rectangular sections as linearly polarized waves. An example will be shown.
This will be explained in detail below using the drawings.

FIG. 4 is a diagram showing a schematic structure of a polarization splitter showing an embodiment of the present invention. In the figure, 8 is a strip line type circularly polarized wave generator, 9 is a conversion waveguide,
10 is a partition wall polarizer, 11 is a metal plate, 12a, 12
b is a converter that extracts linearly polarized waves separated by the metal plate 11;

As shown in FIG. 4, a strip line type circularly polarized wave generator 8 is arranged. First, from the left side of the circularly polarized wave generator 8, the linearly polarized wave E _V shown by the solid arrow
Consider the case where is incident. The linearly polarized wave E _V is
It has an inclination of ±45° with respect to E _V and can be decomposed into two mutually orthogonal linearly polarized waves E _C and E _L.
By the way, by choosing the constants of the strip line appropriately, the polarized wave E _C parallel to the strip line will have a phase delay of 45 degrees when it passes through the line, and the polarized wave E _L perpendicular to the line direction will pass through the line. Therefore, the linearly polarized wave E _V
is converted into right-handed circularly polarized wave (RHCP) as shown by the solid line in FIG. 4 by passing through the strip line. By the same principle, the linearly polarized wave E _H shown by the dotted line is transmitted through the circularly polarized wave generator 8 and converted into a left-handed circularly polarized wave (LHCP) shown by the dotted line. The right-handed and left-handed circularly polarized waves RHCP and LHCP propagate through the conversion waveguide 9 and reach the bulkhead polarizer 10 .

Here, the operation of the partition wall polarizer 10 will be briefly explained. 5 and 6 are schematic diagrams showing the operation of the partition wall polarizer 10, and a, b, and c are diagrams showing the behavior of the electric field at the entrance, middle, and end, respectively.

First, consider the case where a right-handed circularly polarized wave shown by a solid line is incident on the partition wall polarizer 10 shown in FIG.

As shown in FIG. 4, the right-handed circularly polarized wave RHCP can be decomposed into two mutually orthogonal linearly polarized waves A and B, which have the same amplitude and a 90° phase difference. RHCP
In this case, polarized wave B has a phase delay of 90° with respect to polarized wave A.

Therefore, the right-handed circularly polarized wave shown by the solid line in Figure 4
RHCP is decomposed into polarized wave A shown in FIG. 5a and polarized wave B shown in FIG. 6a, which is delayed in phase by 90 degrees with respect to polarized wave A.

By the way, when the polarized wave A advances to the state shown in Figure 5b,
The effect of the metal plate 11 causes a phase delay. By appropriately selecting the shape of the metal plate 11, the polarized wave A in the partition wall polarizer 10 can be delayed in phase by 90 degrees with respect to the polarized wave B.

Therefore, the electric field of the right-handed circularly polarized wave RHCP divided by the metal plate 11 in FIG. 4 is the same phase superposition of the electric fields in FIG. 5 c and FIG. 6 c, as shown in FIG. 7. All the power will be split into the rectangular waveguide on the right. Therefore, the linearly polarized wave E _V shown by the solid line in FIG. 4 can be extracted by the converter 12a on the right side of the figure. According to the same principle of operation, the left-handed circularly polarized wave LHCP has its entire power split into the rectangular waveguide on the left, so the linearly polarized wave E _H shown by the dotted line in Figure 4 can be extracted by the left converter 12b. can.

As explained above, by configuring the polarization demultiplexer as shown in FIG. 4, mutually orthogonal linearly polarized waves can be easily demultiplexed in the direction of the tube axis of the waveguide in space.

〔Effect of the invention〕

As explained above, this invention comprises a circularly polarized wave generator that converts linearly polarized waves into circularly polarized waves in space, and a partition wall polarizer, so that, like a conventional polarized beam splitter, Since there is no need for a structure in which the sub-waveguide is orthogonal to the main waveguide, the cross-sectional dimension of the polarization splitter can be made equal to or smaller than that of the main waveguide. Therefore, great effects can be expected in multi-beam antennas, etc. in which a large number of horn antennas are arranged side by side.

[Brief explanation of drawings]

1 and 2 are schematic structural diagrams of a conventional polarization splitter, FIG. 3 is a diagram showing an example of the use of a polarization splitter, and FIG. 4 is a schematic structural diagram showing an embodiment of the present invention. 5 to 8 are diagrams showing the operating principle of the partition wall polarizer used in the present invention, in which 1 is a circular waveguide, 2 is an orthogonal sub-waveguide, 3 is a coaxial sub-waveguide, 4 is a coupling window, 5 is a shorting rod, 6 is a horn antenna, 7 is a splitter, 8 is a circularly polarized wave generator, 9 is a conversion waveguide, 10 is a bulkhead polarizer, 11 is a metal plate, 12 is It is a converter. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A tapered metal plate is provided to divide the cross section of a square waveguide into two rectangular cross sections with equal areas, and each waveguide receives two circularly polarized waves, right-handed and left-handed. A partition wall polarizer that separates the linearly polarized wave into the two rectangular cross sections, a converter that takes out the linearly polarized wave split from the partition wall polarizer, and the square guide provided between the partition wall polarizer and the space. It is equipped with a conversion waveguide that has the same cross-sectional dimensions as the wave tube or extends in a square or circular shape in a tapered shape, and a circularly polarized wave generator that converts linearly polarized waves into circularly polarized waves. A polarization demultiplexer characterized in that linearly polarized waves are demultiplexed in the tube axis direction of the square waveguide using a circularly polarized wave generator, a conversion waveguide, and a partition wall polarizer. 2 Meander line is a circularly polarized wave generator that converts linearly polarized waves into circularly polarized waves in space.
2. The polarization demultiplexer according to claim 1, characterized in that a strip line type circularly polarized wave generator such as a line or a grid is used.