Dual horn and antenna device

Abstract

To provide a dual horn for angle diversity that is low cost and has high performance and stable quality, and an antenna device using the same.SOLUTION: A dual horn for angular diversity includes a metallic hollow tube having a substantially rectangular cross-sectional shape in a plane perpendicular to the longitudinal direction, and a metallic partition plate incorporated in the hollow tube so as to divide the cross-section of the hollow tube into two rectangles. The antenna device also includes a dual horn in a primary radiator.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a dual horn and an antenna device.

Background Art

[0002] As a countermeasure against fading in over-the-horizon communication (OH communication), an angle diversity method is used. Over-the-horizon communication is communication between points where the transmitting and receiving antennas cannot see each other. It uses radio waves from ultra-high frequency to microwave, and utilizes the scattering phenomenon of radio waves caused by atmospheric turbulence in the troposphere (atmospheric region from the earth's surface to an altitude of about 10 kilometers) to achieve communication over a distance of several hundred kilometers. The fading phenomenon is a phenomenon in which the received radio wave becomes weak or is greatly refracted due to abnormal propagation of the radio wave caused by meteorological conditions such as air temperature and water vapor (humidity) in the air, resulting in an unstable reception state.

[0003] The diversity method is a method that utilizes the fact that when the propagation paths and frequencies of radio waves in space are different, the temporal changes of short-term fading are different. It simultaneously receives and synthesizes signals sent through different propagation paths or frequencies to improve communication quality. Among them, as shown in FIG. 10(a), the antenna device of the angle diversity method has a configuration in which the transmitting antenna is on one surface, the transmitting horn is one (single horn), the receiving antenna is on one surface, and the receiving horn is two (dual horn). As shown in FIG. 10(b), in the receiving antenna of the angle diversity method, horns with multiple directivities (horn 1, horn 2) are installed at different angles, receive radio waves arriving from different directions respectively, and synthesize the received signals.

[0004] As a device for realizing such a dual horn, for example, there is one in which two elementary pipes (pre-formed as pipes) are arranged side by side (see, for example, Non-Patent Document 1). In the technique disclosed in Non-Patent Document 1, the angles of the two horns are adjusted and joined and fixed so as to obtain an optimal reception beam separation angle (included angle). For fixing, for example, the joint surfaces of the elementary pipes are brazed over the entire surface.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The following analysis is provided by the present invention.

[0007] In a dual horn using the angle diversity method, in order to suppress the gain degradation of one horn and suppress the level degradation at the beam intersection, it is important to make the separation angle (the angular difference in the antenna beam direction by each horn) of the two horns as small as possible. For example, it is known that by bringing the horns as close as possible to each other and setting the separation angle to about 0.5 to 1.0°, the gain degradation is minimized.

[0008] However, in the technique disclosed in Non-Patent Document 1, since a dual horn is configured using two elementary pipes, the distance between the two horns cannot be made smaller than twice the wall thickness of the elementary pipes (the distance at which they contact each other). Also, the distance depends on the brazing accuracy. Therefore, the two horns cannot always be arranged at an optimal angle, and in an antenna device using the same, the gain degradation and the level degradation cannot be completely suppressed.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a dual horn for angular diversity having high performance and stable quality at low cost, and an antenna device using the same.

Means for Solving the Problems

[0010] According to a first aspect of the present invention, a metal hollow tube having a substantially rectangular cross-sectional shape in a plane orthogonal to the longitudinal direction, and a metal partition plate incorporated in the hollow tube so as to divide the cross section of the hollow tube into two rectangles, a dual horn for angular diversity is provided. More specifically, the partition plate is provided with ventilation holes, the diameter of the ventilation holes is approximately 1 / 40 of the wavelength of the passing radio wave, the joint between the hollow tube and the partition plate is brazed.

[0011] According to a second aspect of the present invention, an antenna device in which a primary radiator includes the above dual horn is provided.

Effects of the Invention

[0012] According to the present invention, it is possible to provide a dual horn for angular diversity having high performance and stable quality at low cost, and an antenna device using the same.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0014] Hereinafter, an overview of an embodiment of the present invention (hereinafter referred to as this embodiment) will be described with reference to the drawings. Note that the attached reference numerals in the drawings are for convenience and are attached to each element as an example for assisting understanding, and are not intended to limit the present invention to the illustrated embodiments.

[0015] In this embodiment, the dual horn used in the angle diversity type antenna device is realized by inserting a metal partition plate into a hollow tube made by combining members obtained by processing sheet metal.

[0016] Prior to the description of the dual horn of this embodiment, the usage mode of the dual horn of this embodiment will be described. FIGS. 1(a) to 1(c) are diagrams for explaining the usage mode of the dual horn 100 of this embodiment.

[0017] As shown in FIGS. 1(a) and 1(b), the dual horn 100 of the present embodiment is used as the primary radiator 920 of the antenna device 900 including the reflector 910. The antenna device 900 is, as described above, used for out-of-sight (OH) communication, and is, for example, a parabolic antenna or the like with a diameter of about 10 m or more. Further, the primary radiator 920 is installed at the focal point of the reflector 910.

[0018] FIG. 1(b) is an enlarged view of the primary radiator 920, and FIG. 1(c) is an enlarged view of the dual horn 100. As shown in these figures, the dual horn 100 of the present embodiment is incorporated into the primary radiator 920 via flanges 310, 320, 330, etc., receives radio waves reflected by the reflector 910, and transmits radio waves toward the reflector 910. The dual horn 100 has a size of, for example, about 640 mm or more in overall length.

[0019] The dual horn 100 is composed of, for example, two horns (radio wave paths), i.e., the upper first tube 110 and the lower second tube 120 in the figure, as shown in FIGS. 2(a) and 2(b). There is no particular limitation on the relationship between the longitudinal lengths of the first tube 110 and the second tube 120. For example, as shown in FIG. 2(a), both may have the same length. Also, as shown in FIG. 2(b), both may have different lengths.

[0020] Hereinafter, in the present embodiment, as shown in FIG. 2(b), the case where the longitudinal length L2 of the second tube 120 is shorter than the longitudinal length L1 of the first tube 110 (L2 < L1) will be taken as an example for explanation. For example, this configuration is suitable when the first tube 110 is used for both transmission and reception and the second tube 120 is used only for reception.

[0021] The dual horn 100 of the present embodiment includes a hollow tube 210 formed of a metal plate and a rectangular partition plate 220 formed of a metal plate, as shown in FIGS. 3(a) and 3(b). As described above, the partition plate 220 is incorporated into the hollow tube 210.

[0022] As shown in Fig. 3(a), the hollow tube 210 is a square prism with a square (rectangular) cross-section in each part of the extending direction. More specifically, it includes a top wall 210t and a bottom wall 210b that are parallel to each other, and a right side wall 210r and a left side wall 210l that are parallel to each other.

[0023] The top wall 210t has a rectangular shape with a length of L1 in the longitudinal direction and a length of X1 in the direction perpendicular to the longitudinal direction. Also, the bottom wall 210b has a rectangular shape with a length of L2 in the longitudinal direction and a length of X1 in the direction perpendicular to the longitudinal direction.

[0024] As shown in Fig. 3(a), the right side wall 210r and the left side wall 210l have a rectangular shape with a length of L1 in the longitudinal direction and a length of Y1 in the direction perpendicular to the longitudinal direction, and at one corner of the rectangle, there is a notch cut out in a rectangular shape along the side of the rectangle. The length of the notch part in the longitudinal direction is L1 - L2, and the length in the direction perpendicular to it is Y2. Note that Y1 - Y2 and Y2 are approximately the same length.

[0025] As shown in Fig. 3(b), the partition plate 220 is a plate-shaped member in the shape of a rectangle with a length of L1 in the longitudinal direction and a length of X1 in the direction perpendicular to the longitudinal direction.

[0026] As shown in Fig. 3(c), the partition plate 220 is incorporated at a position parallel to the top wall 210t and the bottom wall 210b and separated from the bottom wall 210b by Y2. That is, the partition plate 220 is incorporated into the hollow tube 210 so as to divide the rectangle of the cross-section of the hollow tube 210, forms the bottom wall of the first tube 110, and forms the top wall of the second tube 120. Note that the part of the partition plate 220 that exceeds the length L2 of the bottom wall 210b forms only the low wall of the first tube 110.

[0027] As a result, as shown in Fig. 2(b) and Fig. 3(c), two radio wave paths of the first tube 110 with a length of L1 and the second tube 120 with a length of L2 are formed side by side in a closely adjacent manner vertically in the illustrated mode.

[0028] Note that the metal plate forming the hollow tube 210 and the partition plate 220 is, for example, brass (further, it may be silver-plated), oxygen-free copper (pure copper), etc. This is because they are low-cost, have little reflection loss and passing loss, and are easily available.

[0029] Next, the details of each component will be described.

[0030] As shown in FIG. 4, the hollow tube 210 of the present embodiment includes a U-shaped first member 211 and a flat second member 212.

[0031] The first member 211 is formed, for example, by bending a sheet metal so that the cross-sectional shape in a plane orthogonal to the longitudinal direction is substantially U-shaped. The first member 211 is a member corresponding to the top wall 210t, the left side wall 210l, and the bottom wall 210b of the hollow tube 210.

[0032] As shown in FIG. 5(a), a predetermined number of convex portions (teeth) 231 for engaging with the second member 212 are formed at the longitudinal edges of the surfaces of the first member 211 corresponding to the top wall 210t and the bottom wall 210b. Also, a predetermined number of fitting holes 232 for fitting the convex portions (teeth) of the partition plate 220, which will be described later, are formed at the positions on the surface of the first member 211 corresponding to the left side wall 210l for attaching the partition plate 220. Further, it is desirable to provide a predetermined number of confirmation holes 233 for checking the brazing situation during brazing between the fitting holes 232.

[0033] The second member 212 is a member corresponding to the right side wall 210r of the hollow tube 210.

[0034] On both edges of the second member 212 along the longitudinal direction, a predetermined number of concave portions 241 for engaging with the convex portions 231 of the first member 211 are provided at positions corresponding to the convex portions 231 of the first member 211. Also, at the position where the partition plate 220 is to be attached, a predetermined number of fitting holes 242 for fitting the convex portions (tabs) of the partition plate 220 are formed. It is desirable to provide a predetermined number of confirmation holes 243 for checking the situation around the solder during soldering, which will be described later, between the fitting holes 242 and the fitting holes 242.

[0035] Also, as shown in FIGS. 5(a)-5(c), at the position corresponding to the fitting hole 232 of the first member 211 on one edge of the partition plate 220 along the longitudinal direction, a convex portion (tab) 251 that fits into the fitting hole 232 of the first member 211 is formed, and at the position corresponding to the fitting hole 242 of the second member 212 on the other edge, a convex portion (tab) 251 that fits into the fitting hole 242 of the second member 212 is formed.

[0036] Furthermore, the partition plate 220 of the present embodiment is provided with one or more ventilation holes 252. The diameter of the ventilation holes 252 is made sufficiently small with respect to the wavelength of the radio wave passing through the first pipe 110 and the second pipe 120, which are radio wave paths. For example, it is about 1 / 40. Specifically, it is 6 mm or less. Preferably, it is about 3 mm. Note that the position of the ventilation holes 252 is not limited. However, after manufacturing the dual horn of the present embodiment, a position visible by the naked eye is desirable.

[0037] Note that the convex portion (tab) 231 of the first member 211 and the concave portion 241 of the second member 212 may be provided on members opposite to the above-mentioned members, respectively. That is, the first member 211 may be provided with a concave portion, and the second member 212 may be provided with a convex portion (tab) at a corresponding position. Also, the number of the convex portions 231 and 251 may be one or more, and the number may be appropriately selected as needed. Also, it is desirable that a plurality of the convex portions 231 and 251 are provided at predetermined intervals, but the intervals do not have to be constant.

[0038] The manufacturing procedure will be specifically described.

[0039] First, perform cutting and bending operations on a metal plate to produce the first member 211, the second member 212, and the partition plate 220.

[0040] Next, as shown in FIG. 6(a), combine the first member 211, the second member 212, and the partition plate 220 by engaging their respective convex portions (teeth) and concave portions, and engaging the convex portions (teeth) with the fitting holes.

[0041] Here, for example, first, engage the convex portion 251 of the partition plate 220 with the fitting hole 232 of the first member 211. Then, engage the convex portion 251 of the partition plate 220 with the fitting hole 242 of the second member 212, and engage the convex portion 231 of the first member with the concave portion 241 of the second member 212.

[0042] After that, pour the heated brazing material into the gaps between the convex and concave portions, and between the engaged convex portions (teeth) of the fitting holes. That is, inject the brazing material used for brazing from the outside of the hollow tube 210 of the dual horn 100 into the joint portion between the plate materials or the joint portion between the fitting teeth and the plate material. In FIG. 6(b), the brazing location is shown as a thick dashed line as an example.

[0043] Then, visually check (using a fiber scope, camera, etc. if necessary) through the confirmation holes 233 and 243 whether the brazing material has spread sufficiently.

[0044] After that, perform an airtightness confirmation test. Here, fill both the first tube 110 and the second tube 120 of the dual horn 100 with air, submerge them in water, and check for the presence or absence of air bubbles.

[0045] In the airtightness confirmation test of this embodiment, for example, as shown in FIG. 7(a), lids are fixed (attached) to the second opening 152 and the third opening 153 among the three openings of the dual horn 100. The lid is fixed, for example, by sandwiching a packing in between and screwing it. Then, a lid with a hose attached is fixed to the first opening 151 in the same manner as above, air is sent in by an air compressor or the like through the hose, and the radio wave paths (the first tube 110 and the second tube 120) of the dual horn 100 are filled with air. Then, while continuing to fill with air, the entire dual horn 100 is submerged in water, and the presence or absence of the generation of bubbles is confirmed.

[0046] As described above, conventionally, as shown in FIG. 9, a dual horn having a structure in which two plain tubes are joined is manufactured in this embodiment by disposing a partition plate 220 in a hollow tube 210 having a rectangular cross-section so as to divide the cross-section into two rectangles, thereby forming a first tube 110 serving as a first radio wave path and a second tube 120 serving as a second radio wave path. Also, both the hollow tube 210 and the partition plate 220 are formed by sheet metal working of a metal plate.

[0047] Therefore, in the dual horn 100 of this embodiment, the distance between the first radio wave path and the second radio wave path is only the thickness of the partition plate 220 which is a metal plate. Therefore, compared with the structure of combining two conventional plain tubes, the distance between the two radio wave paths can be made closer. Thereby, gain degradation can be suppressed, and the performance of the dual horn 100 is improved.

[0048] Also, since the dual horn 100 of this embodiment is formed by sheet metal working of a metal plate, the material is a metal plate. Since the metal plate is easily available, there is less variation in the production lead time due to the procurement situation compared to the case of separately manufacturing or purchasing single tubes or plain tubes. That is, according to this embodiment, the production lead time is stabilized.

[0049] In addition, in this embodiment, a dual horn 100 is formed by joining a plurality of sheet metal processed metal plates. Each member before joining is provided with claws for fitting, fitting holes, and recesses. And at the time of joining, these claws and fitting holes, and claws and recesses are fitted together. Therefore, since the assembly accuracy is stabilized, the dimensional variation of the finished product is reduced. In addition, since the mounting error of the parts is also reduced, the labor for remanufacturing due to this is also reduced. As a result, the quality and performance of the dual horn 100 of this embodiment are stabilized.

[0050] Furthermore, in the conventional structure, in order to join two plain tubes, as shown by the thick dashed line and shading in FIG. 9, brazing needs to be performed over the entire joining surface. Also, for the portions of the joining surface other than the outer periphery (for example, the shaded portion), the brazing state cannot be confirmed. On the other hand, in the dual horn 100 of this embodiment, as shown in FIG. 6(b) above, brazing is performed by pouring brazing material into the fitting holes 232, 242 or the recess 241 with respect to the joining portion. For this reason, the brazing location is only the outer peripheral portion of the hollow tube 210 of the dual horn 100. Also, confirmation holes 233, 243 are provided. Therefore, there is no difficult-to-access location during the brazing operation, and visual confirmation of the joining portion is easy.

[0051] Also, in the dual horn 100 of this embodiment, as described above, the brazing location is only the outer peripheral portion of the hollow tube 210. Therefore, the area heated for brazing is smaller than that of the conventional structure. For this reason, the time and thermal deformation required for brazing are reduced accordingly, the cost can be suppressed, and the quality of the product is also improved.

[0052] Furthermore, in the conventional structure shown in FIG. 9, the route length of the radio wave path changes depending on the accuracy during brazing of the plain tubes. Also, since the thickness of the brazing is not stable, the distance between the two plain tubes, that is, the separation between the two horns is not stable. According to the dual horn 100 of this embodiment, there are no such uncertain factors.

[0053] Furthermore, in the dual horn 100 of the present embodiment, two radio wave paths (first tube 110 and second tube 120) are formed by inserting a partition plate 220 of a metal plate. That is, the two radio wave paths are formed by the partition plate 220. And since this partition plate 220 is a metal plate, it can be easily processed. For example, as described above, ventilation holes 252 can be provided. Thereby, the first tube 110 and the second tube 120 can be put in a ventilated state.

[0054] In the conventional structure, since there is no ventilation between the two radio wave paths, as shown in FIG. 7(b), it is necessary to separately fill air into the first tube and the second tube and perform a submersion test. However, in the dual horn 100 of the present embodiment, since the two radio wave paths are in a ventilated state, as shown in FIG. 7(a) above, airtightness can be confirmed by one air filling and submersion test. Therefore, the labor of the final test during manufacturing can be reduced.

[0055] Also, generally, for the waveguide used for the primary radiator 920, during operation, in order to prevent moisture from entering from the outside, for example, a device such as a dehydrator is connected and dry air is sent in at a certain pressure. This is to prevent corrosion inside the tube and a decrease in transmission characteristics due to adhesion of moisture by preventing the intrusion of moisture from the outside.

[0056] In the conventional structure, since there is no ventilation between the two radio wave paths, it is necessary to connect a dehydrator to each of them, and the structure becomes complicated. However, according to the dual horn 100 of the present embodiment, since the two radio wave paths are in a ventilated state, it is only necessary to connect a dehydrator to one of the radio wave paths.

[0057] As described above, according to the dual horn 100 of the present embodiment, an angle diversity dual horn having high performance and stable quality at low cost and an antenna device using the same can be realized.

[0058] <Modification example> In the above-described embodiment, the hollow tube 210 has a configuration in which a first member 211 formed by bending a sheet metal into a U shape and a flat second member 212 are combined. However, the members constituting the hollow tube 210 are not limited to these shapes. For example, two members (a third member and a fourth member) each formed by bending a sheet metal into a hook shape (L shape) may be combined.

[0059] In this case, the development view, the assembled view, and the view for explaining the brazing portion are shown in FIGS. 8(a) to 8(c), respectively.

[0060] As shown in FIG. 8(a), the third member 213 forms the top wall 210t and the left side wall 210l of the hollow tube 210 into a substantially L-shaped cross-sectional structure. The fourth member 214 forms the right side wall 210r and the bottom wall 210b of the hollow tube 210 into a substantially L-shaped cross-sectional structure.

[0061] Note that, as in the above-described embodiment, convex portions and concave portions are provided at the ends along the longitudinal direction in an engageable manner. In addition, a fitting hole and a confirmation hole are provided at the position where the partition plate 220 is attached.

[0062] As shown in FIG. 8(b), these convex and concave portions are engaged, the claws of the partition plate 220 are fitted into the fitting holes, and the dual horn 100 is assembled.

[0063] Then, brazing is performed at the location indicated by the thick dashed line in FIG. 8(c) to complete the dual horn 100.

[0064] In the configuration of this modification, for example, when the first tube 110 and the second tube 120 have the same length, two members having the same shape may be created, so that manufacturing can be more efficient.

[0065] As described above, each embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiments, and further modifications, substitutions, and adjustments can be made without departing from the basic technical idea of the present invention.

[0066] Finally, the preferred forms of the present invention are summarized. (Appendix 1) A metal hollow tube having a substantially rectangular cross-sectional shape in a plane orthogonal to the longitudinal direction, and a metal partition plate incorporated in the hollow tube so as to divide the cross-section of the hollow tube into two rectangles, a dual horn for angular diversity. (Appendix 2) The dual horn according to Appendix 1, wherein it is desirable that the partition plate is provided with ventilation holes. (Appendix 3) The dual horn according to Appendix 1 or Appendix 2, wherein the hollow tube a first member having a U-shaped cross-section formed by sheet metal working of a metal plate, and a flat plate formed from the metal plate, it is desirable to include. (Appendix 4) The dual horn according to any one of Appendices 1 to 3, wherein the partition plate is provided with a convex portion at an edge along the longitudinal direction, it is desirable that the hollow tube is provided with a fitting hole at a position corresponding to the convex portion when incorporating the partition plate. (Appendix 5) The dual horn according to Appendix 3, wherein the first member is provided with a convex portion at an edge along the longitudinal direction, it is desirable that the flat plate is provided with a concave portion at a position corresponding to the convex portion of the first member at an edge along the longitudinal direction. (Appendix 6) The dual horn according to Appendix 4 or Appendix 5, wherein there are a plurality of the convex portions and the fitting holes, it is desirable that the hollow tube is provided with inspection holes between the fitting holes. (Appendix 7) The dual horn according to any one of Appendices 1 to 6, wherein the hollow tube a first region having a first length in the longitudinal direction, and It has a second region having a second length shorter than the first length in the longitudinal direction. The first region constitutes a first pipe portion together with the partition plate. It is desirable that the second region constitutes a second pipe portion together with the partition plate. (Appendix 8) An antenna device in which a primary radiator includes the dual horn according to any one of Appendices 1 to 7.

[0067] In addition, each disclosure of the above patent documents and the like shall be incorporated herein by reference. Within the framework of the entire disclosure of the present invention (including the claims), further modifications and adjustments of the embodiments or examples can be made based on the basic technical idea. Also, within the framework of the disclosure of the present invention, various combinations or selections of various disclosure elements (including each element of each claim, each element of each embodiment or example, each element of each drawing, etc.) are possible. That is, the present invention naturally includes all disclosures including the claims and various modifications and corrections that could be made by those skilled in the art according to the technical idea. In particular, for the numerical ranges described in this document, any numerical value or small range included within the range should be construed as specifically described even in the absence of separate description.

Explanation of Reference Numerals

[0068] 100: Dual horn, 110: First pipe, 120: Second pipe, 151: First opening, 152: Second opening, 153: Third opening 210: Hollow pipe, 210b: Bottom wall, 210l: Left side wall, 210r: Right side wall, 210t: Top wall, 211: First member, 212: Second member, 213: Third member, 214: Fourth member, 220: Partition plate, 231: Protrusion (claw), 232: Fitting hole, 233: Confirmation hole, 241: Recess, 242: Fitting hole, 243: Confirmation hole, 251: Protrusion (claw), 252: Vent hole 310: Flange, 320: Flange, 330: Flange 900: Antenna device, 910: Reflector, 920: Primary radiator

Claims

1. A metal hollow tube having a substantially rectangular cross-sectional shape in a plane orthogonal to the longitudinal direction, and a metal partition plate incorporated in the hollow tube so as to divide the cross-section of the hollow tube into two rectangles, wherein the partition plate is provided with ventilation holes, the diameter of the ventilation holes is approximately 1 / 40 with respect to the wavelength of the passing radio wave, and the joint between the hollow tube and the partition plate is brazed, a dual horn for angular diversity.

2. The dual horn according to claim 1, wherein the hollow tube comprises a first member having a U-shaped cross-section formed by sheet metal working of a metal plate, and a flat plate formed from the metal plate, a dual horn.

3. The dual horn according to claim 1, wherein the partition plate is provided with a convex portion at an edge along the longitudinal direction, and the hollow tube is provided with a fitting hole at a position corresponding to the convex portion when incorporating the partition plate, a dual horn.

4. The dual horn according to claim 2, wherein the first member is provided with a convex portion at an edge along the longitudinal direction, and the flat plate is provided with a concave portion at a position corresponding to the convex portion of the first member at an edge along the longitudinal direction, a dual horn.

5. The dual horn according to claim 3, wherein there are a plurality of the convex portions and the fitting holes, and the hollow tube is provided with inspection holes between the fitting holes, a dual horn.

6. The dual horn according to claim 1, wherein the hollow tube has a first region having a first length in the longitudinal direction and a second region having a second length shorter than the first length in the longitudinal direction, the first region constitutes a first tube portion together with the partition plate, and the second region constitutes a second tube portion together with the partition plate, a dual horn.

7. An antenna device, wherein a primary radiator includes the dual horn according to any one of claims 1 to 6.

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