WO2024047776A1

WO2024047776A1 - Polarization dividing circuit and antenna

Info

Publication number: WO2024047776A1
Application number: PCT/JP2022/032692
Authority: WO
Inventors: 秀憲湯川; 昂大三浦; 太郎平池; 拓真西村; 徹深沢
Original assignee: 三菱電機株式会社
Priority date: 2022-08-31
Filing date: 2022-08-31
Publication date: 2024-03-07

Abstract

This polarization dividing circuit comprises: a conversion waveguide (1) that has a single circular terminal (1A) having a circular cross section perpendicular to a tube axis direction and that has two rectangular terminals (1Ba, 1Bb) the shapes of which are rectangles, the cross section of the conversion waveguide (1) perpendicular to the tube axis direction having a shape that is converted from the circular cross section to the cross section of the two rectangular terminals; and a septum phase plate (2; 2M) that has a plurality of stair-nosings (7a to 7d) and that is placed inside the conversion waveguide. The septum phase plate has a shape in which the width of the septum phase plate in the transverse direction becomes thinner in a step-wise manner. The septum phase plate is placed inside the conversion waveguide such that the front end of the septum phase plate shaped thinner in the step-wise manner is positioned on the circular-terminal side of the conversion waveguide.

Description

Polarization separation circuit and antenna

The present disclosure relates to a polarization separation circuit mainly used in the VHF band, UHF band, microwave band, and millimeter wave band.

A polarization separation circuit with a septum phase plate inserted in a square waveguide is used as a circuit to separate two orthogonal circularly polarized signals (right-handed, left-handed) or two orthogonal linearly polarized signals (vertical, horizontal). known (for example, see FIG. 5 of Non-Patent Document 1).

A conventional polarization separation circuit includes a square waveguide and a septum phase plate, and the square waveguide has one square waveguide terminal and two rectangular waveguide terminals. The septum phase plate is inserted into the square waveguide so that two rectangular waveguides are formed, and is formed so that it tapers stepwise as it approaches the rectangular waveguide terminal and the square waveguide terminal. .

In such a polarization separation circuit, when a circularly polarized signal is input from a square waveguide terminal, the signal is output from a different rectangular waveguide terminal depending on whether the input signal is right-handed or left-handed. Ru. In addition, when a linearly polarized signal is input from a square waveguide terminal, for a linearly polarized signal perpendicular to the septum phase plate, the same electric field direction is applied from two rectangular waveguide terminals, and the septum phase plate For linearly polarized signals horizontal to , the signals are output from the two rectangular waveguide terminals with electric fields facing each other.

In such a polarization separation circuit, the polarization separation characteristics are determined by the dimensions or thickness of the stepped portion of the septum phase plate.

Furthermore, the polarization separation circuit is generally used in connection with a horn antenna having a circular waveguide terminal. Therefore, a converter is provided between the horn antenna and the polarization separation circuit to connect the circular waveguide terminal of the horn antenna and the square waveguide terminal of the polarization separation circuit (for example, (circular to rectangular transition) in Figure 11 of Reference 1.

Conventional polarization separation circuits with square waveguide terminals require converters when used in connection with horn antennas with circular waveguide terminals, so they are configured using polarization separation circuits. There was a problem in that the axis of the antenna became longer by the length of the converter.

The present disclosure has been made to solve such problems, and aims to provide a polarization separation circuit that makes it possible to shorten the axis of the antenna.

A polarization separation circuit according to an embodiment of the present disclosure has one circular terminal whose cross section perpendicular to the tube axis direction is circular and two rectangular terminals whose cross section perpendicular to the tube axis direction is circular. and a septum phase plate having a plurality of step nosings and disposed inside the conversion waveguide, The septum phase plate has a shape in which the width in the width direction of the septum phase plate becomes narrow in a stepwise manner, and the tip of the septum phase plate formed in the stepwise narrow direction is on the side of the circular terminal of the conversion waveguide. is arranged inside the conversion waveguide so as to be located at .

According to the polarization separation circuit according to the embodiment of the present disclosure, it is possible to shorten the axis of the antenna.

1 is a perspective view of a polarization separation circuit for explaining the configuration of a polarization separation circuit according to a first embodiment; FIG. 1 is a plan view of a polarization separation circuit according to Embodiment 1. FIG. 1 is a side view of a polarization separation circuit according to Embodiment 1. FIG. 1 is a perspective view of a conversion waveguide according to Embodiment 1. FIG. 2 is a perspective view of a septum phase plate according to Embodiment 1. FIG. 3 is a plan view of a septum phase plate according to Embodiment 1. FIG. FIG. 3 is a side view of the septum phase plate according to the first embodiment. FIG. 3 is a plan view of a square waveguide as a comparison target whose outer wall has a uniform square shape. 8A is an explanatory diagram for explaining the cross-sectional shape of the septum phase plate at position A and position B in FIG. 8A. FIG. FIG. 7 is a plan view of a conversion waveguide as a comparison target in which the shape of the outer wall is changed from circular to square, and the nosing of the septum phase plate is at right angles. 9A is an explanatory diagram for explaining the cross-sectional shape of the septum phase plate at position A and position B in FIG. 9A. FIG. FIG. 3 is a plan view of a conversion waveguide in which the shape of the outer wall is converted from a circle to a square and the step nosing of the septum phase plate is an acute angle, according to Embodiment 1; 10A is an explanatory diagram for explaining the cross-sectional shape of the septum phase plate at position A and position B in FIG. 10A. FIG. FIG. 7 is a perspective view of a polarization separation circuit for explaining the configuration of a polarization separation circuit according to a second embodiment. FIG. 7 is a side view of a polarization separation circuit according to a second embodiment. FIG. 3 is a perspective view of a septum phase plate according to a second embodiment. FIG. 7 is a side view of a septum phase plate according to a second embodiment. FIG. 7 is a perspective view of a polarization separation circuit for explaining the configuration of a polarization separation circuit according to a third embodiment. FIG. 7 is a perspective view of a conversion waveguide according to Embodiment 3; FIG. 2 is a diagram showing the configuration of an antenna including a polarization separation circuit, a horn antenna, and a filter according to an embodiment.

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that components given the same or similar symbols in the drawings have the same or similar configurations or functions, and overlapping explanations of such components will be omitted.

Embodiment 1.
<Configuration>
FIG. 1 is a perspective view of a polarization separation circuit for explaining the configuration of the polarization separation circuit according to Embodiment 1 of the present disclosure. In FIG. 1, 1 is a conversion waveguide, 2 is a septum phase plate, 3 is a circular waveguide, 4 is a circular waveguide terminal, 5 is a rectangular waveguide, and 6 is a rectangular waveguide terminal. Figure 2 is a plan view of the polarization separation circuit (viewed from a direction perpendicular to the septum phase plate), and Figure 3 is a side view of the polarization separation circuit (viewed from a direction parallel to the septum phase plate). Figure 4 is a perspective view of the conversion waveguide, Figure 5 is a perspective view of the septum phase plate, Figure 6 is a plan view of the septum phase plate (viewed from a direction perpendicular to the septum phase plate), FIG. 7 shows a side view of the septum phase plate (a view seen from a direction parallel to the septum phase plate). In FIGS. 5 and 6, 7 is the nosing of the septum phase plate.

(Circular waveguide)
As shown in FIG. 1, the circular waveguide 3 has an overall cylindrical shape and has circular waveguide terminals, which are circular openings, at both ends. In FIG. 1, one of the two circular waveguide terminals is illustrated as circular waveguide terminal 4. In FIG.

(Rectangular waveguide)

Rectangular waveguides

5a and 5b are waveguides having substantially the same shape. Unless it is necessary to distinguish between them, the

rectangular waveguides

5a and 5b will be collectively referred to as the rectangular waveguide 5 below. As shown in FIG. 1, the rectangular waveguide 5 has a rectangular tube shape with a rectangular cross section as a whole, and has rectangular waveguide terminals that are rectangular openings at both ends. The rectangular waveguide terminal has a cross section corresponding to the cross section of one of the two rectangular terminals 1B (1Ba, 1Bb) of the conversion waveguide 1. In FIG. 1, one of the rectangular waveguide terminals at both ends is illustrated as a rectangular waveguide terminal 6. That is, a rectangular waveguide terminal 6a of the rectangular waveguide 5a and a rectangular waveguide terminal 6b of the rectangular waveguide 5b are illustrated.

(conversion waveguide)
As shown in FIG. 4, the conversion waveguide 1 has one circular terminal 1A having a circular cross section perpendicular to the tube axis direction, and two rectangular terminals 1Ba and 1Bb having rectangular shapes. The conversion waveguide 1 is a waveguide whose cross section perpendicular to the tube axis direction has been converted from a circular cross section to a cross section of two rectangular terminals 1Ba and 1Bb. A septum phase plate 2 is arranged inside the conversion waveguide 1 . By positioning the two rectangular terminals 1Ba and 1Bb adjacently with the septum phase plate 2 sandwiched between them, the two rectangular terminals 1Ba and 1Bb collectively form one substantially square virtual end surface. . Note that the two rectangular terminals 1Ba and 1Bb may be collectively referred to simply as a rectangular terminal 1B.

As an example, as shown in FIG. 1, the circular terminal 1A of the conversion waveguide 1 is connected to the circular waveguide terminal of the circular waveguide 3, and the two rectangular terminals 1Ba and 1Bb is connected to two rectangular waveguide terminals of

rectangular waveguides

5a and 5b, respectively.

(Septum phase plate)
As shown in FIG. 5 or 6, the septum phase plate 2 has a shape in which the width in the transverse direction of the septum phase plate 2 becomes narrower in a stepwise manner. In the septum phase plate 2 having such a shape, as shown in FIG. It is arranged inside the conversion waveguide 1 so as to equally divide the internal space of the septum phase plate 2 . The septum phase plate 2 may be placed in the conversion waveguide 1, for example, by insertion. As another example, the septum phase plate 2 may be placed inside the conversion waveguide 1 by integrally forming the septum phase plate 2 and the conversion waveguide 1 using a 3D printer.

Furthermore, the

nosings

7a, 7b, 7c, and 7d of the septum phase plate 2, which are the parts surrounded by circles in FIG. 5, have acute angles when the septum phase plate 2 is viewed from above, as shown in FIG. It has become. More specifically, the step nosing is made such that a line extending from the side surface of the septum phase plate 2 in the lateral direction of the septum phase plate 2 and a line along the length direction of the septum phase plate 2 form an acute angle in plan view. 7a is formed. Similarly, the nosings 7b to 7d are arranged so that a line extending from the side surface of the septum phase plate 2 in the lateral direction of the septum phase plate 2 and a line along the length direction of the septum phase plate 2 form an acute angle in plan view. It is formed. It is not necessary that all the nosings have an acute angle, and it is possible that at least one nosing has an acute angle.

<Operation>
When a circularly polarized signal is input from the circular waveguide terminal 4, the signal is output from one of the different

rectangular waveguide terminals

6a and 6b depending on whether the waveguide is right-handed or left-handed. In addition, when a linearly polarized signal is input from the circular waveguide terminal 4, the same electric field direction is applied from the two rectangular waveguide terminals 6 for the linearly polarized signal perpendicular to the septum phase plate 2. For linearly polarized signals horizontal to the septum phase plate 2, the signals are outputted from the two rectangular waveguide terminals 6 in opposing electric field directions. In order to achieve good polarization separation, the dimensions of the septum phase plate 2 are adjusted.

Here, regarding the more detailed operation of this embodiment, we will discuss a configuration consisting of a general square waveguide, a configuration in which the outer wall is converted from a circular waveguide to a square waveguide, and a configuration in which the nosing of the septum phase plate is at right angles. , and a configuration in which the outer wall is converted from a circular waveguide to a square waveguide and the nosing of the septum phase plate is an acute angle.

FIG. 8A shows a plan view of a square waveguide as a comparison target whose outer wall has a uniform square shape (viewed from the direction perpendicular to the septum phase plate), and FIG. 8B shows the position A of FIG. An explanatory diagram for explaining the cross-sectional shape of the septum phase plate at position B is shown. In addition, Fig. 9A is a plan view of a conversion waveguide as a comparison target in which the shape of the outer wall has been converted from circular to square and the nosing of the septum phase plate is at right angles (a view seen from the direction perpendicular to the septum phase plate). ), and FIG. 9B is an explanatory diagram for explaining the shape of the cross section of the septum phase plate at position A and position B in FIG. 9A. FIG. 10A is a plan view of the conversion waveguide 1 in which the shape of the outer wall according to Embodiment 1 is converted from circular to square, and the nosings 7a to 7d of the septum phase plate 2 are at acute angles (relative to the septum phase plate). FIG. 10B is an explanatory diagram for explaining the cross-sectional shape of the septum phase plate 2 at positions A and B in FIG. 10A.

In the configuration consisting of a general square waveguide shown in FIG. 8A, the shape of the outer wall is uniform in the tube axis direction, so the cross-sectional shape is the same at position A and position B as shown in FIG. 8B. The phase constant of the signal propagating in the region between position A and position B is constant. Similarly, the phase constants of signals propagating in the regions between positions B and C, between positions C and D, and between positions D and E are constant. Adjusting the dimensions of the septum phase plate under such conditions is relatively easy, and good polarization separation characteristics are likely to be obtained.

On the other hand, as shown in FIG. 9A, in a configuration where the shape of the outer wall of the conversion waveguide is converted from circular to square and the nosing of the septum phase plate is at right angles, the shape of the outer wall changes along the tube axis direction. As shown in FIG. 9B, the position of the septum phase plate is the same at position A and position B, but the cross-sectional shapes are different. In the conversion from a circular waveguide to a square waveguide shown in FIG. 9A, the cutoff frequency shifts to a lower frequency at position B compared to position A, and the phase constant of the signal propagating in the region between position A and position B is It will no longer be constant. The same applies to positions B and C, positions C and D, and positions D and E. This makes it difficult to adjust the dimensions of the septum phase plate, making it difficult to obtain good polarization separation characteristics.

In contrast to the configuration shown in FIG. 9A, in the configuration shown in FIG. 10A according to the first embodiment, the nosings 7a to 7d (see FIG. 5) of the septum phase plate 2 are at acute angles, so as shown in FIG. 10B, The positions of the septum phase plate 2 in the cross section at position A and position B are different. In FIG. 10B, the positional difference is shown as ΔS. The septum phase plate 2 functions as a ridge when viewed in cross section, and as the height of the ridge decreases, the cutoff frequency shifts to a higher frequency range. Therefore, at position B, the shift of the cutoff frequency to the lower range due to the change in the shape of the outer wall is compensated, and the change in the phase constant of the signal propagating in the area between positions A and B is as follows in the case of the configuration shown in FIG. 9A. This results in a reduction compared to that of the configuration shown in FIG. 8A. Therefore, as in the case of the configuration of FIG. 8A, it becomes relatively easy to adjust the dimensions of the septum phase plate 2, and it becomes easier to obtain good polarization separation characteristics.

As shown above, in the configuration in which the outer wall of the conversion waveguide 1 is formed to convert from a circular shape to a square shape, the influence of the outer wall is compensated for by making the step noses 7a to 7d of the septum phase plate 2 at acute angles. and good polarization separation characteristics can be obtained. In addition, since a configuration in which the outer wall is formed so as to convert from a circle to a square has a circular waveguide terminal, when used in connection with a horn antenna having a circular waveguide terminal, a circular waveguide and a square guide are used. A wave tube converter is not required, and the axis can be shortened. Therefore, when used in connection with a horn antenna having a circular waveguide terminal, it is possible to achieve both a short axis and a good polarization separation characteristic.

Embodiment 2.
Next, a polarization separation circuit according to a second embodiment of the present disclosure will be described with reference to FIGS. 11 to 14. FIG. 11 is a perspective view of a polarization separation circuit for explaining the configuration of the polarization separation circuit according to the second embodiment. 12 is a side view of the polarization separation circuit (viewed from a direction parallel to the septum phase plate), FIG. 13 is a perspective view of the septum phase plate 2M, and FIG. 14 is a side view of the septum phase plate 2M ( FIG. In FIGS. 11-13, elements designated by

reference numbers

1 and 3 to 7 are the same as those designated by those reference numbers in FIGS. 1 and 5. Regarding the septum phase plate 2M in FIGS. 11 to 14, the side surface of the septum phase plate 2M (the surface viewed from the direction parallel to the septum phase plate 2M) is trapezoidal, that is, the thickness of the septum phase plate 2M is It differs from the septum phase plate 2 in FIGS. 1 and 5 in that the shape changes into a trapezoidal shape along the tube axis direction.

Similar to the polarization separation circuit according to Embodiment 1, the polarization separation circuit according to the second embodiment also has the effect of obtaining good polarization separation characteristics.

Furthermore, since a change in the shape of the side surface of the septum phase plate 2M has a greater effect on the reflection characteristics than on a change in the phase constant, it is possible to improve the reflection by using the shape of the side surface of the septum phase plate 2M as a design parameter. The effect of improving characteristics can also be obtained.

Embodiment 3.
Next, a polarization separation circuit according to Embodiment 3 of the present disclosure will be described with reference to FIGS. 15 and 16. FIG. 15 is a perspective view of a polarization separation circuit for explaining the configuration of the polarization separation circuit according to the third embodiment. Moreover, FIG. 16 is a perspective view of the conversion waveguide 1M. In FIGS. 15 and 16, elements designated by reference numbers 2 to 4 are the same as those designated by those reference numbers in FIG. The conversion waveguide 1M in FIGS. 15 and 16 differs from the conversion waveguide 1 in FIG. 1 in that a corner R8A is provided at the rectangular terminal 1B of the conversion waveguide 1M. In addition, in FIG. 16, in order to emphasize the corner R8A, the end face of the conversion waveguide 1M is simply drawn as if it were one square terminal, but the conversion waveguide 1M actually has Two rectangular terminals are formed as shown in FIG. Therefore, more specifically, corners R8A are provided at each of the four corners of the two rectangular terminals of the conversion waveguide 1M. Correspondingly, corners R8B are also provided at the corners of the rectangular waveguide terminals of the rectangular waveguides 5Ma and 5Mb.

Similar to the polarization separation circuit according to the first embodiment, the polarization separation circuit according to the present embodiment also has the effect of obtaining good polarization separation characteristics.

Furthermore, since the change in the shape of the outer wall of the conversion waveguide 1M is gentler than when it is converted into a square shape, the effect of the change in the outer wall is reduced, and even better polarization separation characteristics can be obtained. can get.

Further, when another waveguide component manufactured by cutting and having a corner radius is connected to the rectangular waveguide terminal, there is no discontinuity and good reflection characteristics can be obtained.

Note that in any of

Embodiments

1, 2, and 3, since a flat plate ceiling is not formed, it is possible to manufacture a polarization separation circuit by laminating them in the tube axis direction using a 3D printer. Circular waveguides have the advantage that circularity is improved by stacking them in the tube axis direction, and better polarization separation characteristics can be obtained than when they are manufactured in an oblique direction.

Furthermore, an antenna may be constructed by connecting a horn antenna 9 having a circular waveguide terminal to the polarization separation circuit. The connection of the horn antenna 9 to the polarization separation circuit is made to the conversion waveguide 1 for a polarization separation circuit not having a circular waveguide 3; For the circuit, a circular waveguide 3 is used. Another advantage is that an antenna having such a horn antenna 9 can be manufactured using a 3D printer. As shown in FIG. 17, it is possible to manufacture an antenna with a 3D printer in which the circular waveguide terminal of the horn antenna 9 is connected to the circular waveguide terminal 4 of the polarization separation circuit. Although FIG. 17 shows a configuration in which the horn antenna 9 is connected to the polarization separation circuit of the first embodiment, the horn antenna 9 may be connected to the polarization separation circuit of the second or third embodiment.

Furthermore, such an antenna may further include at least one filter. The filter can filter signals in a desired frequency band. There is also the advantage that the antenna with

filter

10a or 10b can be manufactured with a 3D printer. As shown in FIG. 17, it is possible to manufacture with a 3D printer an antenna in which filters 10a and 10b are connected to

rectangular waveguide terminals

6a and 6b of a polarization separation circuit, respectively. Although FIG. 17 shows a configuration in which filters 10a and 10b are connected to the polarization separation circuit of Embodiment 1, it is also possible to connect

filters

10a and 10b to the polarization separation circuit of

Embodiment

2 or 3. .

<Additional notes>
Some aspects of the various embodiments described above are summarized as follows.

(Additional note 1)
The polarization separation circuit of Appendix 1 has one circular terminal (1A) whose cross section perpendicular to the tube axis direction is circular and two rectangular terminals (1Ba, 1Bb) whose cross section is perpendicular to the tube axis direction. a conversion waveguide (1; 1M) having a shape whose cross section is converted from the circular cross section to the cross section of the two rectangular terminals, and a plurality of step noses (7a to 7d), the conversion waveguide a septum phase plate (2; 2M) disposed inside the septum phase plate, the septum phase plate having a shape in which the width in the transverse direction of the septum phase plate is tapered in a stepwise manner; The thin septum phase plate is disposed inside the conversion waveguide so that its tip is located on the circular terminal side of the conversion waveguide.

(Additional note 2)
The polarization separation circuit of Appendix 2 is the polarization separation circuit described in Appendix 1, in which at least one of the plurality of step noses has an acute angle in plan view.

(Additional note 3)
The polarization separation circuit according to attachment 3 is the polarization separation circuit according to

attachment

1 or 2, wherein the septum phase plate (2M) is trapezoidal in side view. circuit.

(Additional note 4)
The polarization separation circuit of Appendix 4 is the polarization separation circuit described in any one of Appendixes 1 to 3, in which the two rectangular terminals have a corner R (8A).

(Appendix 5)
The polarization separation circuit of Appendix 5 is the polarization separation circuit described in any one of Appendixes 1 to 4, which has a circular cross section perpendicular to the tube axis direction, and is connected to the circular terminal. It further comprises a circular waveguide (3).

(Appendix 6)
The antenna of Appendix 6 includes the polarization separation circuit described in any one of Appendixes 1 to 4, and a horn antenna (9) connected to the circular terminal of the conversion waveguide.

(Appendix 7)
The antenna of Appendix 7 includes the polarization separation circuit described in Appendix 5 and a horn antenna (9) connected to the circular waveguide.

(Appendix 8)
The antenna of Appendix 8 is the antenna described in Appendix 6, which includes two rectangular terminals each having a cross section corresponding to the cross section of one of the two rectangular terminals and connected to each of the two rectangular terminals. It further includes waveguides (5a, 5b).

(Appendix 9)
The antenna of appendix 9 is the antenna described in appendix 7, which includes two rectangular terminals each having a cross section corresponding to the cross section of one of the two rectangular terminals and connected to each of the two rectangular terminals. It further includes waveguides (5a, 5b).

(Appendix 10)
The antenna of Appendix 10 is the antenna described in Appendix 8, in which the rectangular waveguide has a corner R (8B).

(Appendix 11)
The antenna of Appendix 11 is the antenna described in Appendix 9, in which the rectangular waveguide has a corner R (8B).

(Appendix 12)
The antenna of Appendix 12 is any one of the antennas described in Appendixes 8 to 11, and further includes two filters (10a, 10b) connected to the two rectangular waveguides.

Note that it is possible to combine the embodiments, or to modify or omit each embodiment as appropriate.

The polarization separation circuit of the present disclosure can be connected to a horn antenna having a circular waveguide terminal and used as an antenna.

1 (1M) conversion waveguide, 1A circular terminal, 1B square terminal, 2 (2M) septum phase plate, 3 circular waveguide, 4 circular waveguide terminal, 5 (5Ma, 5Mb, 5a, 5b) rectangular guide Wave tube, 6 (6a, 6b) Rectangular waveguide terminal, 7 (7a to 7d) Nose, 8 (8A, 8B) Corner R, 9 Horn antenna, 10 (10a, 10b) Filter.

Claims

It has one circular terminal whose cross section perpendicular to the tube axis direction is circular and two rectangular terminals whose cross section is rectangular, and the cross section perpendicular to the tube axis direction is converted from the circular cross section to the cross section of the two rectangular terminals. a conversion waveguide having a shape of
a septum phase plate having a plurality of nosings and disposed inside the conversion waveguide;
Equipped with
The septum phase plate has a shape in which the width in the width direction of the septum phase plate becomes narrow in a stepwise manner, and the tip of the septum phase plate formed in the stepwise narrow direction is connected to a circular terminal of the conversion waveguide. disposed inside the conversion waveguide so as to be located on the side;
Polarization separation circuit.
The polarization separation circuit according to claim 1, wherein at least one of the plurality of step nosings has an acute angle in plan view.
The polarization separation circuit according to claim 2, wherein the septum phase plate is trapezoidal in side view.
The polarization separation circuit according to claim 3, wherein the two rectangular terminals have corners R.
The polarization separation circuit according to claim 4, further comprising a circular waveguide having a circular cross section perpendicular to the tube axis direction and connected to the circular terminal.
A polarization separation circuit according to any one of claims 1 to 4,
a horn antenna connected to the circular terminal of the conversion waveguide;
An antenna.
A polarization separation circuit according to claim 5,
a horn antenna connected to the circular waveguide;
An antenna.
The antenna according to claim 6, further comprising two rectangular waveguides each having a cross section corresponding to the cross section of one of the two rectangular terminals and connected to the two rectangular terminals, respectively.
The antenna according to claim 7, further comprising two rectangular waveguides each having a cross section corresponding to the cross section of one of the two rectangular terminals and connected to each of the two rectangular terminals.
The antenna according to claim 8, wherein the rectangular waveguide has a corner R.
The antenna according to claim 9, wherein the rectangular waveguide has a corner R.
The antenna according to claim 8, further comprising two filters connected to the two rectangular waveguides.
The antenna according to claim 9, further comprising two filters connected to the two rectangular waveguides.
The antenna according to claim 10, further comprising two filters connected to the two rectangular waveguides.
The antenna according to claim 11, further comprising two filters connected to the two rectangular waveguides.