JPS6367803A - polarization converter - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Summary] In a polarization converter, at least two anisotropic phase shifters with a total phase shift of 180 degrees or less are used to convert linearly polarized waves into linearly polarized waves with different directions. The linearly polarized wave is connected in cascade to convert it into an elliptically polarized wave, and this elliptically polarized wave is converted into a linearly polarized wave with a different direction, thereby achieving low density and wide band.

[Industrial application field]

The present invention provides a polarization converter 1 for example, Ku, Ku band (11 to 1
The present invention relates to improvements to polarization converters used in the 5Gllz band).

First, FIG. 3 shows an explanatory diagram of satellite radio wave reception.

Generally, in the case of satellite communication, G
,″.

For example, horizontally polarized radio waves are transmitted from the satellite Ml to cover a predetermined area. At this time, horizontally polarized waves can be received at point B below the satellite, but waves with degree polarization that is shifted from the horizontal polarized waves are received at point A, which is at the edge of the area. At the receiver, the reception level decreases and the signal-to-noise ratio of the demodulated signal deteriorates.

Therefore, as shown in Figure 3 fb), a polarization converter 4 must be inserted between the receiving antenna 3 and the receiver 5 to convert the polarization of the received wave manually into horizontal polarization. However, it is desired that this polarization converter has a lower loss of power and a wider band.

[Conventional technology]

-a, various quantities related to polarization are expressed using the Poincare sphere, and FIG. 4 shows an explanatory diagram of the Poincare sphere.

In the figure, the equator shows linearly polarized waves, the north pole N shows left-handed circularly polarized waves, the south pole S shows right-handed circularly polarized waves, and the area in between shows elliptically polarized waves.

Now, consider the position of the output on the Poincaré sphere when a linearly polarized wave (horizontal polarized wave) indicated by 11 is input to the anisotropic phase shifter.

When the insertion angle of the anisotropic phase shifter is changed, the position of the output wave on the Poincaré sphere is a trajectory that coincides with the equator when the phase shift amount of the anisotropic phase shifter is 0180 degrees, ■ 180 degrees or less When the angle is 90 degrees or more (for example, 120 degrees), the trajectory becomes a figure 8-shaped trajectory that includes the south pole S and the north pole 11. When the angle is 90 degrees, the trajectory becomes a figure 8 shape that passes through the south poles S and N.

This shows that the anisotropic phase shifter can convert linearly polarized waves into linearly polarized waves whose direction has changed, circularly polarized waves, or elliptically polarized waves.

Conventionally, an anisotropic phase shifter with a phase shift amount of 180 degrees has been used as a polarization converter for converting input linearly polarized waves into linearly polarized waves having different directions.

FIG. 5 is a sectional view of a main part of a conventional rally, and FIG. 6 is an explanatory diagram of the operation of FIG. 5. Hereinafter, the operation of FIG. 5 will be explained with reference to FIG. 6.

In FIG. 5, the 180 degree anisotropic phase shifter is a circular waveguide 6.
The dielectric plate 7 has a square cutout at both ends, and a dielectric plate (for example, Teflon slope) 7 of a predetermined length is inserted and fixed therein.

Note that the ■-shaped notch is provided for impedance matching.

Now, as shown in Fig. 6, when a linearly polarized wave is input to the dielectric plate 7 such that the electric field E1° is θ, a component E2 of the electric field E'in parallel to the dielectric plate 7 and a perpendicular component E'in are parallel to the dielectric plate 7. It can be decomposed into component E, but the color of this dielectric plate is different between E and E2.

Therefore, the relative phase of E and E2, which were in the same phase here, is such that E2 is output with a 180 degree delay at the output end.
The incident wave Ein is E. The direction is changed to the ul direction and output as a linearly polarized wave.

That is, when the circular waveguide 6 is rotated as shown by the arrow to change θ, a linearly polarized wave whose direction changes corresponding to θ is obtained, but this is caused by the Poincaré sphere shown in FIG. 4 as described above. Corresponds to moving on the equator.

A phase shifter that can change the relative phase of two orthogonal components as described above is called an anisotropic phase shifter.

Next, FIG. 7 is a configuration diagram of another conventional example, both of which are 180 mm
It is a degree anisotropic phase shifter. In addition, ■ is a side view.

■ shows a front view.

Figure 7 (al is threaded circular and wave tube 10, screw 8
．． Since the amount of phase shift changes depending on the number and thickness of screws 9, the number and size of screws are determined so that the amount of phase shift is 180 degrees. Then, the four-wave tube 8 is rotated to change the direction of the output linearly polarized wave.

Figure 7(b) shows the case of a circular waveguide with an iris.

Iris 111. and 112 and 113 and 114...
By selecting the interval d and the number of sheets, a 180 degree anisotropic phase shifter can be obtained.

FIG. 7 (C1 is a ridge waveguide with height h and length, and by changing , a 180 degree anisotropic shift I'02'h can be obtained.

[Problem that the invention seeks to solve]

In other words, in order to convert a linearly polarized wave into a linearly polarized wave in an arbitrary direction, an anisotropic shift of 180 degrees (° mouthparts) is required as described above, but for this, the length of the dielectric material is, for example, 50-I in Ku band
The length is QOmm, and in the case of an iris, the number of stages is, for example, 6.
~10 stages are required.

However, this poses a problem in that the loss increases and the single frequency characteristic also deteriorates.

[Means for solving problems]

FIG. 1 shows a block diagram of the present invention. The total phase shift amount of the two cascaded anisotropic phase shifters 30 and 31 is 180 degrees or less, and each of the anisotropic phase shifters can be adjusted independently.

[Effect]

In the present invention, the total amount of phase shift is 180 degrees or less. at least 2
Two anisotropic phase shifters are connected in Fi-connection, and each anisotropic phase shifter has a structure that can be adjusted independently. The anisotropic transfer device was used to convert this elliptical polarization into linear polarization in a different direction.

Therefore, since the total phase shift amount is 180 degrees or less, the length of the anisotropic phase shifter is shortened, resulting in lower loss and wider band.

〔Example〕

Figure 1 is a configuration diagram of an embodiment of the present invention, where Figure 1 (al is a side view, Figure 1 (b) is a front view, and Figure 1 (C) is a
FIG. 2 shows an AA' sectional view of b), and FIG. 2 is an explanatory diagram of the operation of FIG. 1.

The operation of FIG. 1 will be described below with reference to FIG. 2 in the case where two anisotropic phase shifters having a phase shift amount of 90 degrees or less are connected in series.

First, as shown in Fig. 1 (a) and Fig. 1 TC), a dielectric material 14°15 having V-shaped notches at both ends as in the conventional example is used.
is inserted into the circular waveguide 16, 17 with flanges 18-21) and fixed. However, since the total displacement of the anisotropic phase shifter is less than 180 degrees, (1,2”L3)
The length is shorter than that of the conventional example.

The conversion principle of this polarization converter is as follows.

First, by rotating one of the anisotropic phase shifters connected in series in this way, for example, the anisotropic phase shifter 30, as shown by the arrow, it has a certain direction as shown on the Poincaré sphere in Fig. 2. B
Convert the linearly polarized wave at point to elliptically polarized wave at point b. Next, when another anisotropic phase shifter 31 is rotated as shown by the arrow to convert the elliptically polarized wave at point b to the linearly polarized wave at point 0, the linearly polarized wave at point B is converted to the linearly polarized wave at point 0, which has a different direction. It will be converted to linear polarization.

In this case, since the total amount of phase shift is 180 degrees or less, the range in which the polarization direction can be changed is 90 degrees or less.

The phase shift amount of each of the two anisotropic phase shifters is designed to be optimal from the angle range in which the polarization direction needs to be converted. For example, two 65 degree anisotropic phase shifters are (total phase shift amount of 130 degrees), the range of linearly polarized waves whose polarization direction can be converted is approximately 145 degrees from the target linearly polarized waves.

After adjusting the two anisotropic phase shifters to the optimal positions,
Each circular waveguide 16 must be fixed.
．． A horizontally long slit 191 as shown in FIG. 1(b) is provided in the flanges 18 to 21 at both ends of the waveguide 17, and the waveguide is fixed to the flanges 24.25 of the fixed circular waveguide 22.23 with screws.

That is, since the amount of phase shift is smaller than 180 degrees, loss and frequency characteristics are improved. It goes without saying that the above description of operation applies similarly to a circular waveguide with a thread, an iris, or a ridge.

〔Effect of the invention〕

As explained in detail above, according to the present invention, there is an effect that a linearly polarized wave can be converted into another linearly polarized wave with low loss and good single frequency characteristics.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the operation of Fig. 1, Fig. 3 is an explanatory diagram of satellite radio wave reception, Fig. 11 is an explanatory diagram of Poincaré Kyubo, and Fig. 5 is a conventional diagram. FIG. 6 is an explanatory diagram of the operation of FIG. 5, and FIG. 7 is a configuration diagram of another conventional example. In the figure, ri6, 10.11.1ff, 16 is a circular waveguide, 30,
31 indicates an anisotropic phase shifter. Kizenaki's tea cellaring 1 Yune/stratification 1 Fig. 4 Cylindrical Shirikou 4 Fig. 512]=n Operation explanatory diagram No. 6 Field

Claims (1)

[Claims] In a polarization converter that converts input linearly polarized waves into linearly polarized waves with different directions, at least two anisotropic phase shifters (30, 3
1. A polarization converter characterized by having a structure in which the total amount of phase shift of the anisotropic phase shifters (1...) is 180 degrees or less, and the insertion directions of the anisotropic phase shifters can be adjusted independently.