Antenna device

Abstract

An antenna device is provided with a polarization conversion unit (16), a first waveguide line (13), and a second waveguide line (21). The first waveguide line is formed in a cross-sectional shape extending in a pipe height direction (D2) in a line cross-section perpendicular to a pipe length direction (D1), and the second waveguide line is formed in a cross-sectional shape extending in a pipe width direction (D3) in the line cross-section. The first waveguide line extends from a conversion space (17) of the polarization conversion unit to one side in the longitudinal direction of the tube, and the second waveguide line extends from the conversion space to the other side in the longitudinal direction of the tube, and a plurality of antenna openings (24) are connected to the second waveguide line. According to such a structure, the first waveguide tube is provided on one side in the tube length direction with respect to the plurality of antenna openings. Consequently, the specification of the antenna device can be prevented from expanding in the tube width direction.

Description

Technical Field

[0001] The present disclosure relates to an antenna device including a waveguide. Background Art

[0002] The antenna device described in Patent Document 1 has a plurality of antenna openings for radiating radio waves, and the plurality of antenna openings are arranged in a row along one direction. Furthermore, a waveguide connecting the plurality of antenna openings to a radio wave transmission and reception source is connected to the row formed by the plurality of antenna openings via a distributor from a lateral direction orthogonal to the one direction.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2022 / 122319 Summary of the invention

[0006] As described above, in the antenna device of Patent Document 1, the waveguide is connected to the row of antenna openings via a distributor from the lateral direction. This causes the combination of the plurality of antenna openings arranged in one direction and the waveguide connected thereto to have a larger lateral width in the lateral direction, and in short, causes the size of the antenna device to be expanded in the lateral direction. The inventors have found the above situation as a result of detailed research.

[0007] The present disclosure has been made in view of the above-mentioned points, and an object of the present disclosure is to provide an antenna device in which a plurality of antenna openings can be easily provided while suppressing the expansion of the specifications in the above-mentioned lateral directions.

[0008] In order to achieve the above object, an antenna device according to one aspect of the present disclosure has:

[0009] A polarization conversion section having a conversion space for propagating radio waves;

[0010] a first waveguide portion having a first waveguide path for propagating radio waves, the first waveguide path being connected to the conversion space from one side in the first direction and extending from the conversion space to one side in the first direction; and

[0011] A second waveguide section is formed with a second waveguide line and a plurality of antenna openings, the second waveguide line is connected to the conversion space from the other side in the first direction and extends from the conversion space to the other side in the first direction, and propagates radio waves, the plurality of antenna openings are connected to the second waveguide line from one side in a second direction perpendicular to the first direction, are open to the external space toward one side in the second direction, and are arranged along the first direction,

[0012] The conversion space has one end disposed on one side in the first direction and connected to the first waveguide and another end disposed on the other side in the first direction and connected to the second waveguide.

[0013] The polarization conversion unit propagates radio waves between one end and the other end of the conversion space, and changes the vibration direction of the electric field of the radio waves in such a manner that the electric field of the radio waves vibrates along a third direction perpendicular to the first direction and the second direction at one end of the conversion space and vibrates along the second direction at the other end of the conversion space.

[0014] The first waveguide is formed into a cross-sectional shape extending in the second direction in a cross-sectional shape perpendicular to the first direction, that is, a cross-sectional shape of the waveguide.

[0015] The second waveguide tube is formed into a cross-sectional shape extending in the third direction in the tube cross section.

[0016] Thus, the first waveguide is disposed on one side in the first direction relative to the plurality of antenna openings. Therefore, the relative positional relationship of the first waveguide to the plurality of antenna openings is unlikely to cause the size of the antenna device to expand in the third direction corresponding to the lateral direction.

[0017] Furthermore, since the plurality of antenna openings are connected to the second waveguide as described above, it is easy to provide the plurality of antenna openings according to the length of the second waveguide in the first direction without increasing the size of the antenna device in the third direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view schematically showing a general structure of the antenna device in the first embodiment.

[0019] Figure 2 yes Figure 1 The view in the direction of arrow II in FIG. 1 is a plan view schematically showing the antenna device according to the first embodiment.

[0020] Figure 3 This is a perspective view showing, by wireframe, a part of the first waveguide path, the conversion space, the second waveguide path, the antenna opening, the open space, and the reflection suppression wall in the antenna device according to the first embodiment.

[0021] Figure 4 It is schematically indicated Figure 1 It is a cross-sectional view of the IV-IV section of FIG. 1 , and is also a top view of the first block included in the antenna device of the first embodiment.

[0022] Figure 5 is Figure 1 A cross-sectional view schematically showing the first waveguide tube in an overlapping manner in the VV cross section of FIG.

[0023] Figure 6 It is schematically indicated Figure 1 Cross-sectional view of section VI-VI.

[0024] Figure 7 It is a schematic diagram showing the electric field vibration direction of the radio wave propagated by the antenna device according to the first embodiment.

[0025] Figure 8 is from Figure 5 A cross-sectional view showing a polarization conversion portion selected from the cross-sectional view.

[0026] Fig. 9 In the first embodiment, Figure 1 Part IX is enlarged to show a local enlarged view.

[0027] Fig.10 This is a perspective view showing, by wireframe, a second waveguide path and an antenna opening in an antenna device according to a first comparative example to be compared with the first embodiment.

[0028] Fig.11 This is a diagram showing the gain distribution of the antenna device obtained by computer simulation in the first comparative example.

[0029] Fig.12 This is a diagram showing the gain distribution of the antenna device obtained by computer simulation in the first embodiment.

[0030] Fig.13 is a cross-sectional view schematically showing a schematic structure of an antenna device in a second embodiment, and is similar to Figure 1 Quite a picture.

[0031] Fig.14 yes Fig.13 The view viewed in the XIV direction in FIG. 1 is a plan view schematically showing the antenna device according to the second embodiment.

[0032] Fig.15 It is schematically indicated Fig.13 It is a cross-sectional view taken along the XV-XV section of FIG. 1 and is also a top view of the first block included in the antenna device of the second embodiment, which is similar to Figure 4 Quite a picture.

[0033] Fig.16 It is schematically indicated Fig.13 It is a cross-sectional view of the XVI-XVI section of , and is also a bottom view of the second block included in the antenna device of the second embodiment.

[0034] Fig.17 This is an exploded perspective view showing the antenna device according to the second embodiment decomposed into a first block and a second block.

[0035] Fig.18 This is a perspective view showing a single body of the first block in the antenna device according to the second embodiment in a wire frame.

[0036] Fig.19 This is a perspective view showing a single body of the second block in the antenna device according to the second embodiment in a wire frame.

[0037] Fig. 20 is a cross-sectional view schematically showing a schematic structure of an antenna device in a third embodiment. Figure 1 Quite a picture.

[0038] Fig.21 yes Fig. 20 The view viewed in the direction of arrow XXI in FIG. 1 is a plan view schematically showing the antenna device according to the third embodiment.

[0039] Fig. 22 The antenna device of the third embodiment is decomposed into a first block and a second block to show the exploded perspective view. Fig.17 Quite a picture.

[0040] Fig.23 is a perspective view showing a single body of the second block in the antenna device of the third embodiment in a wireframe format. Fig.19 Quite a picture.

[0041] Fig.24 It is a top view showing an array antenna including a plurality of antenna elements according to a fourth embodiment.

[0042] Fig.25 Yes Fig.24 A three-dimensional diagram of a wireframe representation of an array antenna.

[0043] Fig.26 Yes Fig.24 Part XXVI is enlarged to show a perspective view.

[0044] Fig. 27 Yes means Fig.24 Cross-sectional view of section XXVII-XXVII.

[0045] Fig.28 is a cross-sectional view schematically showing a schematic structure of an antenna device in a fifth embodiment. Figure 1 Quite a picture.

[0046] Fig.29 is a cross-sectional view schematically showing a schematic structure of an antenna device in a sixth embodiment, Fig.28 Quite a picture.

[0047] Fig.30is a cross-sectional view schematically showing a simplified structure of an antenna device in a seventh embodiment, Fig.28 Quite a picture.

[0048] Fig.31 is a cross-sectional view schematically showing a schematic structure of an antenna device in an eighth embodiment, and is similar to Fig.28 Quite a picture.

[0049] Fig.32 It is a plan view schematically showing a general structure of a device including a plurality of antenna devices in a ninth embodiment. DETAILED DESCRIPTION

[0050] Hereinafter, each embodiment will be described with reference to the drawings. In addition, in each of the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

[0051] (First Embodiment)

[0052] In this embodiment, if Figure 1 to Figure 3 As shown in FIG. 1 , an example in which the antenna device 1 of the present disclosure is applied to a device including an MMIC 2 as an electrical component will be described. “MMIC” is an abbreviation of Monolithic Microwave Integrated Circuit.

[0053] In the description of this embodiment, in order to indicate the direction of the antenna device 1, the Figure 1 to Figure 3 The tube length direction D1, tube height direction D2 and tube width direction D3 are shown. The tube length direction D1, tube height direction D2 and tube width direction D3 are directions that intersect each other, and strictly speaking, are directions that are perpendicular to each other. In addition, in this embodiment, the tube length direction D1 corresponds to the first direction of the present disclosure, the tube height direction D2 corresponds to the second direction of the present disclosure, and the tube width direction D3 corresponds to the third direction of the present disclosure. In addition, Figure 3 , described later Fig.10 , Fig.18 , Fig.19 , Fig.23 and Fig.25 In the figure, no hidden line processing is performed, and the hidden lines are represented by solid lines like the contour lines.

[0054] MMIC2 is a semiconductor device including an input / output unit 3 for transmitting and receiving radio waves. MMIC2 is a transceiver device provided corresponding to the antenna device 1. In this embodiment, the operating frequency of the radio waves transmitted and received by MMIC2 is set to a frequency band corresponding to millimeter waves. In addition, the operating frequency of the radio waves transmitted and received by MMIC2 is not limited to a frequency corresponding to millimeter waves, and may be a frequency other than millimeter waves.

[0055] The electrical substrate 4 is a printed circuit board formed with a plurality of wiring patterns using conductive members such as metal foil. The thickness direction of the electrical substrate 4 coincides with the tube height direction D2 described above. The electrical substrate 4 has a surface 4a formed on one side in the tube height direction D2 and another surface 4b formed on the other side in the tube height direction D2. Furthermore, the MMIC 2 is mounted on the other surface 4b of the electrical substrate 4. A substrate through hole SH is formed in the electrical substrate 4 at a position opposite to the input / output portion 3 of the MMIC 2, which passes through the electrical substrate 4 along the tube height direction D2. In addition, Figure 1 , the solder Sd for joining the MMIC 2 to the other surface 4 b of the electric substrate 4 is shown.

[0056] A plurality of spacers 5 are disposed on one surface 4 a of the electric board 4 . The spacers 5 are made of, for example, a conductive material. The spacers 5 are fixed to the electric board 4 .

[0057] The antenna device 1 is disposed on one surface 4a of the electric board 4 via a plurality of spacers 5. The antenna device 1 is fixed to the electric board 4 by screwing, bonding, or the like while being in contact with each of the plurality of spacers 5.

[0058] The antenna device 1 is an antenna for transmitting radio waves transmitted and received by the MMIC 2. The antenna device 1 is a structure ST having a laminated structure in which two conductive blocks BC1 and BC2 are laminated in a tube height direction D2. The two blocks BC1 and BC2 are made of metal.

[0059] In addition, at least one of the two blocks BC1 and BC2 may not be composed of a metal block, but may be composed of a block formed by forming a conductive film such as a metal film on the surface of a resin block by plating, or a block formed of a conductive material other than metal.

[0060] The antenna device 1 has two blocks BC1 and BC2 which are connected to each other by screwing, bonding, etc. The antenna device 1 is fixed to the electric board 4 in a posture where the tube height direction D2 coincides with the thickness direction of the electric board 4 .

[0061] The two blocks BC1 and BC2 constituting the antenna device 1 are specifically a first block BC1 and a second block BC2 which are stacked in this order from the side close to the electric board 4, that is, the other side in the tube height direction D2.

[0062] like Figure 1 , Figure 2 , Figure 4As shown, the two blocks BC1 and BC2 are formed into rectangular shapes that are the same when viewed along the tube height direction D2, that is, when viewed from above. In addition, the two blocks BC1 and BC2 are formed into the same size when viewed from above so as to overlap each other in the tube height direction D2.

[0063] Parts of the surfaces of the first block BC1 and the second block BC2 facing each other are in contact with each other, thereby electrically connecting the two blocks BC1 and BC2.

[0064] The first block BC1 is provided so that the surface on the other side in the tube height direction D2 of the first block BC1 faces the one side 4a of the electric board 4 via a plurality of spacers 5. Although not shown in the figure, the first block BC1 is electrically connected to the ground pattern included in the wiring pattern formed on the one side 4a of the electric board 4 via at least a part of the plurality of spacers 5. Since the second block BC2 is electrically connected to the first block BC1, it is electrically connected to the ground pattern of the electric board 4 via the first block BC1. The ground pattern of the electric board 4 is set to the ground potential.

[0065] Functionally, the antenna device 1 includes an external port 11, a first waveguide section 12, a polarization conversion section 16, and a second waveguide section 20. The external port 11 is provided in the first block BC1 of the two blocks BC1 and BC2, and the first waveguide section 12, the polarization conversion section 16, and the second waveguide section 20 are provided across the first block BC1 and the second block BC2, respectively.

[0066] The external port 11 is formed in the first block BC1 as an opening hole opened to the other side in the tube height direction D2, and is provided so as to propagate radio waves between the MMIC 2. The external port 11 is formed in the first block BC1 at a position facing the input / output portion 3 of the MMIC 2 with the substrate through hole SH sandwiched therebetween. Thus, radio waves can be propagated between the external port 11 and the MMIC 2.

[0067] The first waveguide section 12 is included in a waveguide that serves as a propagation path for radio waves between the MMIC 2 and the polarization converter 16. In this embodiment, since the external port 11 opens to the first waveguide section 12, the entire first waveguide section 12 serves as a waveguide between the MMIC 2 and the polarization converter 16.

[0068] A first waveguide 13 extending along the tube length direction D1 and propagating radio waves is formed inside the first waveguide portion 12. The first waveguide 13 is formed between the first block BC1 and the second block BC2 as a cavity extending along the tube length direction D1. For example, in the present embodiment, the boundary BD between the first block BC1 and the second block BC2 is located in the middle of the range occupied by the first waveguide 13 in the tube height direction D2. The first waveguide 13 has one end 13a disposed on one side in the tube length direction D1 and another end 13b disposed on the other side in the tube length direction D1. In addition, Figure 3 In the figure, the external port 11 and the peripheral portion of the external port 11 in the first waveguide 13 are omitted.

[0069] In addition, the first waveguide 13 is arranged on one side in the tube height direction D2 with respect to the external port 11, and the external port 11 is connected to the first waveguide 13 from the other side in the tube height direction D2. The external port 11 is opened to the first waveguide 13 at a position on one side in the tube length direction D1 in the first waveguide 13, specifically, at a position near one end 13a of the first waveguide 13. Therefore, the first waveguide 13 extends from the vicinity of the external port 11 to the conversion space 17 of the polarization conversion section 16 described later.

[0070] like Figure 3 , Figure 5 As shown, the first waveguide 13 is formed into a rectangular cross-section extending in the tube height direction D2 in a cross section perpendicular to the tube length direction D1. That is, the dimension of the first waveguide 13 in the tube height direction D2 is larger than the dimension in the tube width direction D3. Figure 5 Show Figure 1 The VV section of FIG. 1 shows a first waveguide 13, in which the first waveguide 13 is not actually shown. Figure 5 In order to show the relative positional relationship between the first waveguide channel 13 and a conversion space 17 described later, the first waveguide channel 13 is represented by a two-dot chain line as a virtual line.

[0071] In addition, if Figure 1 , Figure 2 , Figure 4 As shown, the first waveguide section 12 has an end wall 121 disposed on one side of the tube length direction D1 in the first waveguide section 12. The end wall 121 is disposed at the end of the first waveguide 13, that is, the one end 13a, and contacts the first waveguide 13 so as to face the other side in the tube length direction D1, thereby forming the one end 13a thereof. Therefore, the end wall 121 is disposed near the external port 11 and disposed on one side of the external port 11 in the tube length direction D1.

[0072] The polarization conversion section 16 is provided between the first waveguide section 12 and the second waveguide section 20 in the tube length direction D1, and a conversion space 17 for propagating radio waves is formed inside the polarization conversion section 16. The conversion space 17 is formed as a cavity between the first block BC1 and the second block BC2. For example, in the present embodiment, the boundary BD between the first block BC1 and the second block BC2 is located in the middle of the range occupied by the conversion space 17 in the tube height direction D2. The conversion space 17 has one end 17a provided on one side in the tube length direction D1 and the other end 17b provided on the other side in the tube length direction D1.

[0073] The first waveguide 13 is connected to one end 17a of the conversion space 17. Specifically, the other end 13b of the first waveguide 13 and the one end 17a of the conversion space 17 are at the same position in the tube length direction D1 and are connected to each other. That is, the first waveguide 13 is connected to the conversion space 17 from one side in the tube length direction D1 and extends from the conversion space 17 to one side in the tube length direction D1.

[0074] Therefore, the first waveguide 13 is connected to the MMIC 2 via the external port 11 at the side opposite to the conversion space 17 side, and forms a radio wave propagation path between the MMIC 2 and the conversion space 17. The first waveguide 13 propagates radio waves between the MMIC 2 and the conversion space 17.

[0075] In addition, the second waveguide 21 of the second waveguide section 20 described later is connected to the other end 17b of the conversion space 17. Specifically, one end 21a of the second waveguide 21 and the other end 17b of the conversion space 17 are at the same position in the tube length direction D1 and are connected to each other. The function of the polarization conversion section 16 will be described later.

[0076] The second waveguide section 20 is configured as a waveguide serving as a propagation path for radio waves between each of the plurality of antenna openings 24 and the polarization converter 16. A second waveguide path 21 extending along the tube length direction D1 and propagating radio waves is formed inside the second waveguide section 20.

[0077] The second waveguide 21 is formed between the first block BC1 and the second block BC2 as a cavity extending along the tube length direction D1. For example, in the present embodiment, the boundary BD between the first block BC1 and the second block BC2 is located in the middle of the range occupied by the second waveguide 21 in the tube height direction D2. The second waveguide 21 has one end 21a provided on one side in the tube length direction D1 and the other end 21b provided on the other side in the tube length direction D1.

[0078] As described above, the second waveguide 21 is connected to the conversion space 17 at one end 21a of the second waveguide 21. Therefore, the second waveguide 21 is connected to the conversion space 17 from the other side in the tube length direction D1 and extends from the conversion space 17 to the other side in the tube length direction D1.

[0079] like Figure 3 , Figure 5 , Figure 6 As shown, the second waveguide 21 has a rectangular cross-sectional shape extending in the tube width direction D3 in the tube cross section. That is, the dimension of the second waveguide 21 in the tube width direction D3 is larger than the dimension in the tube height direction D2.

[0080] And, if Figure 6 As shown, the second waveguide section 20 has first to fourth side wall surfaces 201, 202, 203, 204, which are wall surfaces of the second waveguide 21 and form four sides of the rectangular cross-sectional shape of the second waveguide 21. Among the first to fourth side wall surfaces 201, 202, 203, 204, the first side wall surface 201 and the second side wall surface 202 are formed into a plane shape perpendicular to the tube height direction D2, and the third side wall surface 203 and the fourth side wall surface 204 are formed into a plane shape perpendicular to the tube width direction D3.

[0081] The first side wall surface 201 is provided on one side in the tube height direction D2 with respect to the second waveguide 21, and contacts the second waveguide 21 toward the other side in the tube height direction D2. The second side wall surface 202 is provided on the other side in the tube height direction D2 with respect to the second waveguide 21, and contacts the second waveguide 21 toward one side in the tube height direction D2. The third side wall surface 203 is provided on one side in the tube width direction D3 with respect to the second waveguide 21, and contacts the second waveguide 21 toward the other side in the tube width direction D3. The fourth side wall surface 204 is provided on the other side in the tube width direction D3 with respect to the second waveguide 21, and contacts the second waveguide 21 toward one side in the tube width direction D3.

[0082] In addition, if Figure 1 , Figure 2 , Figure 4 As shown, the second waveguide tube section 20 has another end wall 205 provided as a short-circuit section at the other side in the tube length direction D1 in the second waveguide tube section 20. The other end wall 205 contacts the second waveguide tube 21 at the other end 21b of the second waveguide tube 21, facing the one side in the tube length direction D1, thereby forming the other end 21b thereof.

[0083] Here, the electric field vibration direction De of the radio wave propagated by the first and second waveguides 13 and 21 is referred to as the electric field vibration direction De of the radio wave. The electric field vibration direction De of the radio wave is, for example, Figure 7 It is known that the electric field vibration direction De of the radio wave propagating through a rectangular waveguide whose cross section is a rectangular shape is along the short side of the rectangular shape.

[0084] Therefore, if Figure 3 , Figure 5 As shown, in the first waveguide 13, the electric field vibration direction De of the radio wave is made along the tube width direction D3 according to the cross-sectional shape of the first waveguide 13. And the radio wave of the first waveguide 13 propagates in the first waveguide 13 while the electric field vibration direction De of the radio wave is maintained along the tube width direction D3. On the other hand, in the second waveguide 21, the electric field vibration direction De of the radio wave is made along the tube height direction D2 according to the cross-sectional shape of the second waveguide 21. And the radio wave of the second waveguide 21 propagates in the second waveguide 21 while the electric field vibration direction De of the radio wave is maintained along the tube height direction D2.

[0085] Therefore, if Figure 1 , Figure 3 , Figure 5 As shown, the polarization conversion section 16 allows radio waves to propagate in the conversion space 17 between one end 17a connected to the first waveguide 13 and the other end 17b connected to the second waveguide 21, and at the same time changes the electric field vibration direction De of the radio wave by 90 degrees around the axis along the tube length direction D1.

[0086] Specifically, the polarization conversion unit 16 propagates the radio wave between one end 17a and the other end 17b of the conversion space 17 and changes the electric field vibration direction De of the radio wave as follows. That is, the polarization conversion unit 16 propagates the radio wave and changes the electric field vibration direction De of the radio wave between the one end 17a and the other end 17b in such a manner that the electric field of the radio wave vibrates along the tube width direction D3 at the one end 17a of the conversion space 17 and vibrates along the tube height direction D2 at the other end 17b of the conversion space 17.

[0087] Specifically, if Figure 3 , Figure 5 , Figure 8As shown in FIG. 1 , the contour shape of the conversion space 17 in the cross section of the pipeline is a shape formed by a pair of rectangular shapes RCT arranged in a staggered manner in the pipe height direction D2 and the pipe width direction D3 and partially overlapping each other. That is, the contour shape of the conversion space 17 in the cross section of the pipeline, that is, the cross-sectional contour shape of the conversion space 17, is a point-symmetrical shape. In addition, the conversion space 17 has a spatial shape in which the cross-sectional contour shape of the conversion space 17 extends in the pipe length direction D1.

[0088] In addition, if Figure 5 As shown, the two end edges 17d and 17e of the conversion space 17 in the tube height direction D2 are respectively consistent with the two end edges 13d and 13e of the first waveguide 13 in the tube height direction D2. In addition, the two end edges 17f and 17g of the conversion space 17 in the tube width direction D3 are respectively consistent with the two end edges 21d and 21e of the second waveguide 21 in the tube width direction D3. In addition, when viewed in the direction along the tube length direction D1, the center of the other end 13b of the first waveguide 13, the center of the one end 21a of the second waveguide 21, and the center of the conversion space 17 are respectively indicated by Figure 5 The points Pc are consistent with each other. Figure 8 The two-dot chain line is an imaginary line recorded to facilitate understanding of the rectangular shape RCT, and therefore does not represent an actually existing outer shape.

[0089] Since the conversion space 17 has the above-mentioned spatial shape, the polarization conversion section 16 propagates the radio wave as follows when transmitting the radio wave and when receiving the radio wave. For example, when transmitting the radio wave, the polarization conversion section 16 propagates the radio wave entering the conversion space 17 from the first waveguide 13 in the conversion space 17 while changing the electric field vibration direction De of the radio wave from the tube width direction D3 to the direction along the tube height direction D2, and sends the radio wave from the conversion space 17 to the second waveguide 21. In addition, when receiving the radio wave, the polarization conversion section 16 propagates the radio wave entering the conversion space 17 from the second waveguide 21 in the conversion space 17 while changing the electric field vibration direction De of the radio wave from the tube height direction D2 to the direction along the tube width direction D3, and sends the radio wave from the conversion space 17 to the first waveguide 13.

[0090] like Figure 1 to Figure 3 As shown, in addition to the second waveguide 21, a plurality of antenna openings 24 and a plurality of open spaces 26 constituting antenna radiation elements are formed in the second waveguide 20. In this embodiment, five antenna openings 24 and five open spaces 26 are formed. The plurality of antenna openings 24 are arranged along the tube length direction D1, and the plurality of open spaces 26 are also arranged along the tube length direction D1.

[0091] In the description of the present embodiment, the five antenna openings 24 are referred to as the first antenna opening 241, the second antenna opening 242, the third antenna opening 243, the fourth antenna opening 244, and the fifth antenna opening 245 in order from one side in the tube length direction D1. When the first to fifth antenna openings 241, 242, 243, 244, and 245 are collectively described, they are sometimes simply referred to as antenna openings 24 or antenna openings 241 to 245.

[0092] The same applies to the five open spaces 26. That is, the five open spaces 26 are referred to as the first open space 261, the second open space 262, the third open space 263, the fourth open space 264, and the fifth open space 265 in order from one side in the tube length direction D1. When the first to fifth open spaces 261, 262, 263, 264, and 265 are collectively described, they are sometimes simply referred to as the open space 26 or the open spaces 261 to 265.

[0093] The plurality of antenna openings 24 are respectively used to propagate radio waves between the second waveguide 21 and the external space SP of the antenna device 1. Specifically, the plurality of antenna openings 24 are respectively provided on one side in the tube height direction D2 with respect to the second waveguide 21, and are connected to the second waveguide 21 from the one side in the tube height direction D2. The plurality of antenna openings 24 are respectively formed as through holes that penetrate the second waveguide portion 20 from the second waveguide 21 to the one side in the tube height direction D2.

[0094] In addition, a plurality of open spaces 26 are respectively provided on one side in the tube height direction D2 with respect to the plurality of antenna openings 24. The open spaces 26 are open to the external space SP of the antenna device 1 on one side in the tube height direction D2, and are connected to the antenna openings 24 on the other side in the tube height direction D2. Therefore, the plurality of antenna openings 24 are respectively open to the external space SP toward one side in the tube height direction D2. And, the second waveguide 21 is connected to the external space SP via the antenna openings 24 and the open spaces 26 in sequence. Thus, between the second waveguide 21 and the external space SP, radio waves can be propagated via a plurality of combinations of the antenna openings 24 and the open spaces 26, respectively. The plurality of combinations of the antenna openings 24 and the open spaces 26 are formed in parallel between the second waveguide 21 and the external space SP.

[0095] In addition, the plurality of antenna openings 24 are formed in an oval shape extending in the tube length direction D1 in a plan view. The second waveguide tube portion 20 has a wall surface of the antenna opening 24 formed as a through hole, that is, an opening peripheral wall surface 25 with respect to the plurality of antenna openings 24. The opening peripheral wall surface 25 is formed in an annular shape in a plan view so as to surround the antenna opening 24, and faces the antenna opening 24 and contacts therewith.

[0096] And, if Figure 1 , Figure 6 , Fig. 9 As shown, each of the plurality of antenna openings 24 is formed in a tapered shape as a hole that expands more toward one side in the tube height direction D2. That is, the opening peripheral wall surface 25 surrounding the antenna opening 24 is inclined relative to the tube height direction D2 in such a manner that the antenna opening 24 expands more toward one side in the tube height direction D2. For example, in the present embodiment, the opening peripheral wall surface 25 is an inclined surface that extends linearly and is inclined relative to the tube height direction D2 in any of the sections perpendicular to the tube length direction D1 and the sections perpendicular to the tube width direction D3.

[0097] For example, the dimension W1 of the other end 24b of the opening on the other side of the antenna opening 24 in the tube height direction D2 in the tube length direction D1 is configured to be approximately 0.4 to 0.8 times the wavelength of the radio wave at the operating frequency. The wavelength of the radio wave at the operating frequency is the wavelength of the radio wave at a representative frequency included in the operating frequency, and can be interpreted as the wavelength of the radio wave at the center frequency of the operating frequency, for example. In addition, Fig. 9 The VI-VI section line shows Figure 6 section position.

[0098] The plurality of antenna openings 24 are arranged along the tube length direction D1. Figure 2 , Figure 3 The antenna openings 24 are arranged as shown in the figure so that the phases of the radio waves are aligned in the plurality of antenna openings 24. That is, the plurality of antenna openings 24 are arranged along the tube length direction D1 while being alternately arranged to be offset to one side and the other side in the tube width direction D3 with respect to the center axis Cb of the second waveguide 21. The center axis Cb of the second waveguide 21 is a center line obtained by connecting the centers of the second waveguide 21 in the tube cross section along the tube length direction D1, and is a straight line extending along the tube length direction D1.

[0099] Specifically, if Figure 1 to Figure 3 As shown, the first antenna opening 241, the third antenna opening 243 and the fifth antenna opening 245 are arranged on one side in the tube width direction D3 relative to the central axis Cb of the second waveguide 21. In addition, the second antenna opening 242 and the fourth antenna opening 244 are arranged on the other side in the tube width direction D3 relative to the central axis Cb of the second waveguide 21.

[0100] The pitch PT of the plurality of antenna openings 24 in the tube length direction D1 is determined based on the tube wavelength λg of the radio waves propagating in the second waveguide 21. For example, the pitch PT of the antenna openings 24 in the tube length direction D1 is set to "0.5×λg" or approximately "0.5×λg".

[0101] By arranging the antenna openings 24 in this way, the antenna device 1 of the present embodiment is configured so that the phases of radio waves are aligned in all the antenna openings 24 .

[0102] like Figure 1 to Figure 3 , Figure 6 , Fig. 9 As shown, the second waveguide section 20 has an open space bottom surface 27 and an open space side surface 28 facing and contacting the open spaces 26. That is, the second waveguide section 20 has the same number of open space bottom surfaces 27 and open space side surfaces 28 as the open spaces 26.

[0103] The plurality of open space bottom surfaces 27 are respectively provided on the other side in the tube height direction D2 with respect to the open space 26, and are connected to the open space 26 from the other side in the tube height direction D2. In other words, the plurality of open space bottom surfaces 27 face the open space 26 toward one side in the tube height direction D2. For example, the plurality of open space bottom surfaces 27 are respectively formed in a plane shape orthogonal to the tube height direction D2, and have a rectangular outer shape consisting of two sides along the tube length direction D1 and two sides along the tube width direction D3.

[0104] The antenna openings 24 are formed in the plurality of open space bottom surfaces 27. Therefore, the plurality of open space bottom surfaces 27 are formed to expand from one open end 24a of the antenna opening 24 on one side in the tube height direction D2 in the tube length direction D1 and the tube width direction D3.

[0105] The plurality of open space side surfaces 28 extend from the periphery of the open space bottom surface 27 formed in a rectangular shape to one side in the tube height direction D2. Furthermore, the plurality of open space side surfaces 28 are formed in an annular shape so as to surround the open space 26 over the entire circumference thereof, and are formed toward the inner side of the annular shape. Therefore, in a plan view, the open space side surface 28 is also formed in the same rectangular shape as the open space bottom surface 27, and the open space 26 is formed inside the open space side surface 28.

[0106] Due to such a configuration, in the configuration relationship with the antenna opening 24, the plurality of open space side surfaces 28 are respectively provided on one side in the tube height direction D2 with respect to the plurality of antenna openings 24. Furthermore, the plurality of open space side surfaces 28 independently surround the plurality of antenna openings 24 in a plan view and are formed into a ring shape away from the antenna openings 24. In addition, the open space side surfaces 28 correspond to the opening surrounding surfaces of the present disclosure.

[0107] like Figure 1 to Figure 3 , Figure 6 , Fig. 9As shown, the second waveguide tube portion 20 has a plurality of reflection suppression walls 30 disposed in the second waveguide tube 21. Furthermore, compared with a structure in which a plurality of reflection suppression walls 30 are not disposed, the plurality of reflection suppression walls 30 suppress the reflection of radio waves in the second waveguide tube 21. In short, the plurality of reflection suppression walls 30 reduce the reflection of radio waves in the second waveguide tube 21. The same number of reflection suppression walls 30 as the antenna opening 24 is disposed, that is, five reflection suppression walls 30 are disposed. The reflection suppression walls 30 correspond to the in-tube protrusions of the present disclosure. In addition, in Figure 3 In FIG. 1 , in order to easily identify the reflection suppressing wall 30 , the reflection suppressing wall 30 is indicated by dotted hatching.

[0108] In the description of the present embodiment, the five reflection suppression walls 30 are referred to as the first reflection suppression wall 301, the second reflection suppression wall 302, the third reflection suppression wall 303, the fourth reflection suppression wall 304, and the fifth reflection suppression wall 305 in order from one side in the tube length direction D1. When the first to fifth reflection suppression walls 301, 302, 303, 304, and 305 are collectively described, they are sometimes simply referred to as the reflection suppression walls 30 or the reflection suppression walls 301 to 305.

[0109] In addition, Figure 1 In the cross section of the antenna device 1 shown, the first, third, and fifth reflection suppression walls 301, 303, and 305 are not actually shown, but are shown in FIG. Figure 1 In order to illustrate the arrangement of each reflection suppression wall 30, the first, third, and fifth reflection suppression walls 301, 303, and 305 are indicated by double-dashed lines as imaginary lines. Fig. 9 In the Fig. 9 In the cross section of the antenna device 1 shown, the first reflection suppressing wall 301 is not actually shown, but the first reflection suppressing wall 301 is indicated by a two-dot chain line as an imaginary line.

[0110] Specifically, the plurality of reflection suppression walls 30 are respectively arranged corresponding to the antenna openings 24. Here, the expression that a certain reflection suppression wall 30 included in the plurality of reflection suppression walls 30 is arranged corresponding to a certain antenna opening 24 included in the plurality of antenna openings 24 can be expressed in another way, for example, as follows. That is, such corresponding arrangement means, in other words, Figure 1 The illustration shows that the above-mentioned certain antenna opening 24 among the plurality of antenna openings 24 is arranged closest to the above-mentioned certain reflection suppression wall 30 when viewed in the direction along the tube width direction D3 .

[0111] Specifically, if Figure 1 to Figure 3As shown, the first reflection suppression wall 301 of the plurality of reflection suppression walls 30 is arranged corresponding to the first antenna opening 241, and the second reflection suppression wall 302 is arranged corresponding to the second antenna opening 242. In addition, the third reflection suppression wall 303 is arranged corresponding to the third antenna opening 243, the fourth reflection suppression wall 304 is arranged corresponding to the fourth antenna opening 244, and the fifth reflection suppression wall 305 is arranged corresponding to the fifth antenna opening 245. And, for example, when the first reflection suppression wall 301 and the first antenna opening 241 are used as an example for explanation, as shown in FIG. Figure 1 As shown, the first antenna opening 241 among the plurality of antenna openings 24 is arranged closest to the first reflection suppression wall 301 when viewed in the direction along the tube width direction D3 .

[0112] And, if Figure 1 to Figure 3 , Figure 6 As shown, the first reflection suppression wall 301, the third reflection suppression wall 303, and the fifth reflection suppression wall 305 are respectively formed in the shape of a rib protruding from the fourth side wall surface 204 to one side in the tube width direction D3, and extend along the tube height direction D2. On the other hand, the second reflection suppression wall 302 and the fourth reflection suppression wall 304 are respectively formed in the shape of a rib protruding from the third side wall surface 203 to the other side in the tube width direction D3, and extend along the tube height direction D2.

[0113] Specifically, the plurality of reflection suppression walls 30 are disposed in the second waveguide 21 so as to be alternately offset to one side and the other side in the tube width direction D3 with respect to the central axis Cb of the second waveguide 21 , and are arranged along the tube length direction D1 .

[0114] Furthermore, the plurality of reflection suppression walls 30 are arranged in the tube width direction D3 so as to be offset to the side opposite to the side where the antenna opening 24 corresponding to the reflection suppression wall 30 is offset relative to the central axis Cb of the second waveguide 21. This can be described as follows by taking the first reflection suppression wall 301 and the first antenna opening 241 corresponding thereto as an example. That is, Figure 2 , Figure 3 As shown, the first antenna opening 241 is arranged offset to one side in the tube width direction D3 with respect to the central axis Cb of the second waveguide 21. Furthermore, the first reflection suppression wall 301 is arranged offset to the side opposite to the side in the tube width direction D3 where the first antenna opening 241 is offset with respect to the central axis Cb of the second waveguide 21 (in short, the other side in the tube width direction D3).

[0115] In addition, the arrangement of the plurality of reflection suppression walls 30 in the tube length direction D1 can be described as follows. Figure 1 , Fig. 9As shown, the plurality of reflection suppression walls 30 are respectively at least partially within the range R1 occupied by the antenna opening 24 corresponding to the reflection suppression wall 30 in the tube length direction D1. At the same time, the plurality of reflection suppression walls 30 are respectively arranged to the other side of the antenna opening 24 corresponding to the reflection suppression wall 30 in the tube length direction D1.

[0116] For example, the second reflection suppression wall 302 and the second antenna opening 242 corresponding thereto are used as an example to explain this, and the following description can be given. That is, the second reflection suppression wall 302 at least partially falls within the range R1 occupied by the second antenna opening 242 in the tube length direction D1. At the same time, the second reflection suppression wall 302 is arranged offset to the other side in the tube length direction D1 relative to the second antenna opening 242.

[0117] In addition, the reflection suppression wall 30 at least partially falls within the above range R1 in the tube length direction D1. In other words, at least a portion of the reflection suppression wall 30 falls within the above range R1. Fig. 9 As shown, the entirety of the second reflection suppression wall 302 falls within the above-mentioned range R1 of the second antenna opening 242 .

[0118] like Figure 6 , Fig. 9 As shown, in this embodiment, the boundary BD between the first block BC1 and the second block BC2 is located in the middle of the range occupied by the reflection suppression wall 30 in the tube height direction D2. Therefore, each of the plurality of reflection suppression walls 30 includes a side wall portion 30a disposed on one side of the boundary BD between the first and second blocks BC1 and BC2 in the tube height direction D2 and another side wall portion 30b disposed on the other side of the boundary BD between the first and second blocks BC1 and BC2 in the tube height direction D2. The side wall portion 30a and the other side wall portion 30b are arranged in a straight line along the tube height direction D2, but are separated from each other, and a small gap in the tube height direction D2 is formed between the side wall portion 30a and the other side wall portion 30b.

[0119] The shapes and arrangements of the plurality of reflection suppressing walls 30 provided in this manner are determined by, for example, computer simulation, so as to suppress reflection of radio waves in the second waveguide 21 .

[0120] In detail, the plurality of reflection suppression walls 30 are formed and arranged so that the radio waves reflected in the second waveguide 21 by the antenna opening 24 corresponding to the reflection suppression wall 30 are offset by the radio waves reflected back by the reflection suppression wall 30. For example, if the first reflection suppression wall 301 and the first antenna opening 241 corresponding thereto are used as an example for explanation, it can be described as follows. That is, the first reflection suppression wall 301 is formed and arranged so that the radio waves reflected in the second waveguide 21 by the first antenna opening 241 are offset by the radio waves reflected back by the first reflection suppression wall 301.

[0121] Next, the operation of the antenna device 1 will be described. Figure 1 to Figure 4 As shown, in the antenna device 1 of the present embodiment, for example, if a radio wave is output from the input / output section 3 of the MMIC 2, the radio wave is input to the external port 11. The radio wave input to the external port 11 sequentially passes through the first waveguide 13 and the conversion space 17 from the external port 11 to reach the second waveguide 21. The radio wave reaching the second waveguide 21 propagates in the second waveguide 21, is distributed to the five antenna openings 24, and is radiated from the five antenna openings 24 to the external space SP through the open space 26.

[0122] Furthermore, for example, when the input / output unit 3 of the MMIC 2 receives radio waves from the external space SP, the antenna device 1 propagates the radio waves in a direction opposite to the above-described case where the input / output unit 3 outputs radio waves.

[0123] Here, the results of a computer simulation comparing the antenna device 1 of the present embodiment with the antenna device 80 of the first comparative example compared with the present embodiment are described. In the computer simulation, a radio wave of a specific wavelength is input from the conversion space 17 to the second waveguide 21 .

[0124] In addition, if Fig.10 As shown, the antenna device 80 of the first comparative example is configured such that the opening peripheral wall surface 25 of each antenna opening 24 is not an inclined surface but a vertical surface parallel to the tube height direction D2, and no open space 26 is formed (see Figure 3 ). In addition, the reflection suppression wall 30 is not provided in the antenna device 80 of the first comparative example (refer to Figure 3 ) Except for the above-mentioned contents, the antenna device 80 of the first comparative example is the same as the antenna device 1 of the present embodiment.

[0125] Through the above computer simulation comparing the present embodiment and the first comparative example, it is obtained that Fig.11 , Fig.12 Results shown. Fig.11 is a graph showing the distribution of gain in the antenna device 80 of the first comparative example, Fig.12: is a graph showing the distribution of gain in the antenna device 1 according to the present embodiment.

[0126] Fig.11 The curve Ga and Fig.12 The curve Gc represents the gain distribution on the plane perpendicular to the tube length direction D1. Fig.11 The curve Gb and Fig.12 Curves G1d, G2d, and G3d represent gain distribution on a plane perpendicular to the tube width direction D3.

[0127] in addition, Fig.12 The curve G1d shows the gain distribution obtained when a radio wave with a wavelength of 76 GHz is input. Fig.11 The curves Ga, Gb and Fig.12 The curve G2d represents the gain distribution obtained when a radio wave with a wavelength of 76.5 GHz is input. Fig.12 The curve G3d shows the gain distribution obtained when a radio wave with a wavelength of 77 GHz is input.

[0128] in addition, Fig.12 The curve Gc represents the gain distribution obtained when the wavelengths of the radio waves are 76 GHz, 76.5 GHz, and 77 GHz. If the wavelength of the input radio wave is different, the gain distribution will also be different, but the difference in the gain distribution is small. Fig.12 In the figure, a curve Gc is used to represent the gain distribution.

[0129] According to the results of the computer simulation, Fig.11 , Fig.12 It can be seen that in the antenna device 1 of the present embodiment, when a radio wave with a wavelength of 76.5 GHz is input, a gain improvement of 2.10 dBi is confirmed compared with the antenna device 80 of the first comparative example. In addition, in the antenna device 1 of the present embodiment, even when radio waves with wavelengths of 76 GHz and 77 GHz are input, it is confirmed that the same gain as that when a radio wave with a wavelength of 76.5 GHz is input can be obtained.

[0130] As described above, according to this embodiment, Figure 1 to Figure 3 As shown, the first waveguide 13 is formed into a cross-sectional shape extending in the tube height direction D2 in the tube cross section perpendicular to the tube length direction D1, and the second waveguide 21 is formed into a cross-sectional shape extending in the tube width direction D3 in the tube cross section. In addition, the first waveguide 13 extends from the conversion space 17 of the polarization converter 16 to one side in the tube length direction D1, and the second waveguide 21 extends from the conversion space 17 to the other side in the tube length direction D1, and a plurality of antenna openings 24 are connected to the second waveguide 21.

[0131] According to such a structure, the first waveguide 13 is provided on one side of the tube length direction D1 with respect to the plurality of antenna openings 24. Therefore, the relative positional relationship of the first waveguide 13 with respect to the plurality of antenna openings 24 is unlikely to cause the size of the antenna device 1 to expand in the tube width direction D3. Therefore, it is possible to suppress the size of the antenna device 1 from expanding in the tube width direction D3.

[0132] Thus, since the expansion of the antenna device 1 in the tube width direction D3 is suppressed, when a plurality of antenna devices 1 are provided, for example, the plurality of antenna openings 24 formed in the plurality of antenna devices 1 can be densely arranged in the tube width direction D3.

[0133] Furthermore, since the plurality of antenna openings 24 are connected to the second waveguide tube 21 as described above, the plurality of antenna openings 24 can be easily provided according to the length of the second waveguide tube 21 in the tube length direction D1 without increasing the size of the antenna device 1 in the tube width direction D3.

[0134] In addition, according to the cross-sectional shapes of the first and second waveguides 13 and 21, the first waveguide 13 contributes to the layout of the propagation path of the radio wave and the miniaturization of the antenna device 1. Furthermore, the second waveguide 21 connecting the plurality of antenna openings 24 contributes to the gain improvement and miniaturization of the antenna device 1. Such first waveguide 13 and second waveguide 21 can be used in appropriate locations, respectively, and as a result, the miniaturization and gain improvement of the antenna device 1 can be achieved at the same time.

[0135] (1) In addition, according to this embodiment, Figure 1 to Figure 3 , Figure 6 As shown, the plurality of antenna openings 24 are each formed as a hole that expands toward one side in the tube height direction D2 . Thus, radio waves are concentrated in each of the plurality of antenna openings 24 , and the gain of the antenna device 1 can be improved.

[0136] In addition, a computer simulation was performed to compare the second comparative example and the present embodiment, which differ from the present embodiment only in that the opening peripheral wall surface 25 of each antenna opening 24 is not an inclined surface but a vertical surface parallel to the tube height direction D2. As a result of the computer simulation, it was confirmed that the gain of the antenna device 1 was increased in the present embodiment compared with the second comparative example.

[0137] (2) In addition, according to the present embodiment, the plurality of open space side surfaces 28 are provided on one side in the tube height direction D2 with respect to the plurality of antenna openings 24. Furthermore, the plurality of open space side surfaces 28 surround the plurality of antenna openings 24 independently and form a ring shape in a plan view, and are formed toward the inside of the ring shape. Thus, radio waves are concentrated in each of the open spaces 26 formed inside the plurality of open space side surfaces 28, and the gain of the antenna device 1 can be improved.

[0138] In addition, a computer simulation was performed to compare the third comparative example and the present embodiment, which differ from the present embodiment only in that the antenna opening 24 is directly opened to the external space SP without forming the open space 26, the open space bottom surface 27, and the open space side surface 28. As a result of the computer simulation, it was confirmed that the gain of the antenna device 1 was increased in the present embodiment compared with the third comparative example.

[0139] (3) In addition, according to this embodiment, Figure 1 to Figure 4 As shown, a plurality of reflection suppression walls 30 for suppressing reflection of radio waves in the second waveguide 21 are provided in the second waveguide 21. The reflection suppression walls 30 are arranged corresponding to at least one of the plurality of antenna openings 24. For example, in the present embodiment, the plurality of reflection suppression walls 30 are arranged corresponding to each antenna opening 24, respectively.

[0140] Therefore, the propagation amount of radio waves to the second waveguide 21 can be increased compared to the case where the reflection suppression wall 30 is not provided. In addition, the arrangement and shape of the plurality of reflection suppression walls 30 can be determined individually according to the reflection of radio waves caused by the plurality of antenna openings 24. Thus, the advantage of being able to easily suppress the reflection of radio waves in the second waveguide 21 can be obtained.

[0141] (4) In addition, according to this embodiment, if Figure 1 to Figure 3 As shown, the plurality of antenna openings 24 are alternately arranged to be offset to one side and the other side in the tube width direction D3 with respect to the central axis Cb of the second waveguide 21 and are arranged along the tube length direction D1. In addition, the plurality of reflection suppression walls 30 are also alternately arranged to be offset to one side and the other side in the tube width direction D3 with respect to the central axis Cb of the second waveguide 21 in the second waveguide 21 and are arranged along the tube length direction D1. However, the plurality of reflection suppression walls 30 are arranged to be offset to the side opposite to the side on which the antenna opening 24 corresponding to the reflection suppression wall 30 is offset with respect to the central axis Cb of the second waveguide 21 in the tube width direction D3.

[0142] Therefore, for example, a plurality of reflection suppression walls 30 are arranged at the same positions as the reflection suppression walls 30 in the tube width direction D3. Figure 2Compared with the case on the opposite side of the figure, the amount of projection of the reflection suppressing wall 30 from the third side wall surface 203 or the fourth side wall surface 204 is less restricted by the arrangement of the antenna opening 24. Therefore, the degree of freedom in determining the shapes of the plurality of reflection suppressing walls 30 can be increased.

[0143] (5) In addition, according to this embodiment, Figure 1 , Figure 2 , Fig. 9 As shown, the plurality of reflection suppression walls 30 are at least partially located within the range R1 of the antenna opening 24 corresponding to the reflection suppression wall 30 in the tube length direction D1. In addition, the plurality of reflection suppression walls 30 are arranged to be offset to the other side of the antenna opening 24 corresponding to the reflection suppression wall 30 in the tube length direction D1.

[0144] Therefore, each of the plurality of reflection suppression walls 30 can be appropriately provided so that the radio waves reflected in the second waveguide 21 by the antenna opening 24 corresponding to the reflection suppression wall 30 can be offset by the radio waves reflected back by the reflection suppression wall 30 .

[0145] (Second Embodiment)

[0146] Next, the second embodiment is described. In this embodiment, the differences from the first embodiment are mainly described. In addition, the same or equivalent parts as the above embodiment are omitted or simplified for description. This is also the case in the description of the embodiments described later.

[0147] like Figures 13 to 19 As shown, in this embodiment, the antenna device 1 does not include the reflection suppression wall 30 (see Figure 3 ). Except for this point, this embodiment is the same as the first embodiment. Also, in this embodiment, the effects obtained by the structure common to the first embodiment described above can be obtained in the same manner as the first embodiment.

[0148] in addition, Fig.17 1 is an exploded perspective view showing the antenna device 1 of the present embodiment decomposed into a first block BC1 and a second block BC2. Fig.18 is a three-dimensional diagram showing the first block BC1 in wireframe form. Fig.19 It is a stereoscopic diagram showing the second block BC2 in wire frame.

[0149] (Third Embodiment)

[0150] Next, a third embodiment will be described. In this embodiment, points different from the above-described second embodiment will be mainly described.

[0151] like Figure 20 to Figure 23As shown, in this embodiment, the open space 26 is different from the second embodiment. In this embodiment, the open space 26 is not formed in multiple but in one. And. In this embodiment, the multiple open space side surfaces 28 (refer to Fig.19 ) is replaced by an open space side 29. The open space side 29 corresponds to the opening peripheral surface of the present disclosure.

[0152] Specifically, the open space 26 of the present embodiment is provided on one side in the tube height direction D2 relative to the plurality of antenna openings 24, and is extended so as to overlap with one side in the tube height direction D2 of all the plurality of antenna openings 24. For example, in a plan view, the open space 26 is formed in a rectangular shape extending along the tube length direction D1, and all the plurality of antenna openings 24 fall inside the rectangular shape.

[0153] In this embodiment, since the open space 26 is formed in this way, the open space bottom surface 27 and the open space side surface 29 are not provided in plural but in one each. In addition, a plurality of antenna openings 24 are provided in the open space bottom surface 27 .

[0154] In the present embodiment, the open space side surface 29 extends from the periphery of the open space bottom surface 27 formed in a rectangular shape to one side in the tube height direction D2. Furthermore, the open space side surface 29 is formed in an annular shape so as to surround the open space 26 over its entire circumference and is formed toward the inner side of the annular shape. Therefore, in a plan view, the open space 26 is formed inside the open space side surface 29 formed in an annular shape.

[0155] Due to such an arrangement, in the arrangement relationship with the antenna openings 24, the open space side surface 29 is provided on one side in the tube height direction D2 relative to the plurality of antenna openings 24, similarly to the open space side surface 28 of the second embodiment. Furthermore, the open space side surface 29 surrounds all of the plurality of antenna openings 24 together in a plan view, and is formed in a ring shape away from the plurality of antenna openings 24.

[0156] In addition, the open space side surface 29 is composed of a pair of long side surfaces 291 and a pair of short side surfaces 292. The pair of long side surfaces 291 extend along the tube length direction D1 and are arranged opposite to each other in the tube width direction D3 across the open space 26. In contrast, the pair of short side surfaces 292 extend along the tube width direction D3 and are arranged opposite to each other in the tube length direction D1 across the open space 26. Therefore, the pair of long side surfaces 291 form the long sides of the rectangular shape of the open space side surface 29 in a plan view, and the pair of short side surfaces 292 form the short sides of the rectangular shape.

[0157] In addition, the pair of long side portions 291 are formed into a plane along the tube height direction D2. In contrast, the pair of short side portions 292 are each formed into a concave curved surface. In detail, the pair of short side portions 292 are curved concavely in a cross section perpendicular to the tube width direction D3, and are formed in such a manner that the distance between the pair of short side portions 292 in the tube length direction D1 increases as the distance is closer to the side in the tube height direction D2. Therefore, the pair of short side portions 292 are inclined with respect to the tube height direction D2, and the open space 26 is formed so as to expand as the distance is closer to the side in the tube height direction D2.

[0158] The open space side surface 29 is the same as the open space side surface 28 of the second embodiment except for the points described in this embodiment. Fig. 20 The cross-sectional view of the XVa-XVa section is Fig.15 Likewise, showing Fig. 20 The cross-sectional view of the XVIa-XVIa section is Fig.16 Similarly, the three-dimensional diagram showing the single body of the first block BC1 of this embodiment in wireframe is similar to the Fig.18 same.

[0159] (1) As described above, according to the present embodiment, the open space side surface 29 is provided on one side in the tube height direction D2 relative to the plurality of antenna openings 24. Furthermore, the open space side surface 29 surrounds the plurality of antenna openings 24 together and forms a ring shape in a plan view, and is formed toward the inside of the ring shape. Thus, radio waves are concentrated in the open space 26 formed inside the open space side surface 29, and the gain of the antenna device 1 can be improved.

[0160] Except for the above-described contents, this embodiment is the same as the second embodiment. Also, in this embodiment, similarly to the second embodiment, the effects obtained by the configuration common to the second embodiment described above can be obtained.

[0161] In addition, the present embodiment is a modified example based on the second embodiment, but the present embodiment may be combined with the above-mentioned first embodiment.

[0162] (Fourth Embodiment)

[0163] Next, a fourth embodiment will be described. In this embodiment, points different from the third embodiment described above will be mainly described.

[0164] like Fig.24 , Fig.25 As shown, in this embodiment, two antenna devices 1 are provided. The two antenna devices 1 are arrayed, and an array antenna 51 obtained by integrating the two antenna devices 1 is formed.

[0165] Compared with the antenna device 1 of the third embodiment, the two antenna devices 1 of this embodiment are respectively configured such that the first waveguide path 13 is extended longer and is bent in a plan view at a portion away from the conversion space 17. Except for this point, the two antenna devices 1 of this embodiment are respectively the same as the antenna device 1 of the third embodiment.

[0166] In the description of the present embodiment, one of the two antenna elements 1 is referred to as one side antenna element 1a, and the other of the two antenna elements 1 is referred to as the other side antenna element 1b. In addition, the antenna opening 24 formed in the one side antenna element 1a is referred to as one side antenna opening 247, and the open space 26 formed in the one side antenna element 1a is referred to as one side open space 267. In addition, the antenna opening 24 formed in the other side antenna element 1b is referred to as the other side antenna opening 248, and the open space 26 formed in the other side antenna element 1b is referred to as the other side open space 268.

[0167] The one-side antenna element 1a is arranged on one side of the other-side antenna element 1b in the tube width direction D3. In addition, the one-side antenna element 1a and the other-side antenna element 1b have a symmetrical structure in the tube width direction D3. Figure 24 to Figure 26 As shown, the plurality of one-side antenna openings 247 and the one-side open spaces 267 are arranged side by side on one side in the tube width direction D3 relative to the plurality of other-side antenna openings 248 and the other-side open spaces 268 .

[0168] In addition, the array antenna 51 includes an external exposure surface 52 that is exposed to the external space SP toward one side in the tube height direction D2 and is formed in a plane shape perpendicular to the tube height direction D2. The external exposure surface 52 is arranged between the one side open space 267 and the other side open space 268 in the tube width direction D3. Therefore, the external exposure surface 52 is arranged between the plurality of one side antenna openings 247 and the plurality of other side antenna openings 248 in the tube width direction D3. In other words, the plurality of one side antenna openings 247 are arranged in the tube width direction D3 with respect to the plurality of other side antenna openings 248 so as to sandwich the external exposure surface 52 therebetween.

[0169] In addition, if Fig.26 , Fig. 27 As shown, two choke grooves 531 and 532 are formed on the externally exposed surface 52. The two choke grooves 531 and 532 are formed in such a manner that one side in the tube height direction D2 is open and the other side in the tube height direction D2 becomes the bottom, and extend in the tube length direction D1. In addition, the choke groove 531 of one of the two choke grooves 531 and 532 is arranged on one side in the tube width direction D3 relative to the choke groove 532 of the other. In short, the two choke grooves 531 and 532 are arranged in a row in the tube width direction D3.

[0170] In addition, the two choke grooves 531 and 532 are also provided between the one side open space 267 and the other side open space 268 in the tube width direction D3 as described above, similarly to the above-mentioned arrangement of the externally exposed surface 52. That is, the two choke grooves 531 and 532 are also provided between the plurality of one side antenna openings 247 and the plurality of other side antenna openings 248 in the tube width direction D3.

[0171] Specifically, the two choke slots 531 and 532 are configured to improve the isolation of radio waves between the plurality of one-side antenna openings 247 and the plurality of other-side antenna openings 248. For example, the shape and arrangement of the choke slots 531 and 532 are determined by computer simulation, etc., so as to improve the isolation of the radio waves compared to a case where the choke slots 531 and 532 are not formed and the externally exposed surface 52 is a simple planar shape.

[0172] As described above, according to the present embodiment, the choke slots 531 and 532 are provided between the one antenna opening 247 and the other antenna opening 248. Therefore, the isolation of radio waves between the one antenna opening 247 and the other antenna opening 248 can be improved, and further, the gain of each of the one antenna element 1a and the other antenna element 1b can be improved.

[0173] Except for the above-described contents, this embodiment is the same as the third embodiment. Also, in this embodiment, similarly to the third embodiment, the effects obtained by the configuration common to the third embodiment described above can be obtained.

[0174] In addition, the present embodiment is a modified example based on the third embodiment, but the present embodiment may be combined with the first embodiment or the second embodiment described above.

[0175] (Fifth Embodiment)

[0176] Next, a fifth embodiment will be described. In this embodiment, points different from the third embodiment described above will be mainly described.

[0177] like Fig.28 As shown in FIG. 1 , in this embodiment, the MMIC 2 is not mounted on the other surface 4b of the electrical substrate 4 but on the one surface 4a of the electrical substrate 4. That is, between the first block BC1 of the antenna device 1 and the one surface 4a of the electrical substrate 4, a plurality of spacers 5 are used to ensure a gap for arranging the MMIC 2, and the MMIC 2 is arranged between the first block BC1 and the one surface 4a of the electrical substrate 4. Fig.28 and the following Figure 29 to Figure 31 In, omitted Fig. 20 etc. are diagrams of solder Sd.

[0178] In addition, in this embodiment, the input / output unit 3 (see Fig. 20 ) A connection wiring 41 and an input-output circuit 42 are provided on the electric substrate 4. The connection wiring 41 and the input-output circuit 42 are composed of a conductive wiring pattern formed on one surface 4a of the electric substrate 4.

[0179] The connection wiring 41 is formed so as to be led out from the MMIC 2 along the one surface 4a of the electric substrate 4. One end side of the connection wiring 41 is electrically connected to the terminal of the MMIC 2, and the other end side is electrically connected to the input-output circuit 42.

[0180] The input / output circuit 42 transmits and receives radio waves to and from the external port 11 of the antenna device 1. The input / output circuit 42 functions in the same manner as the input / output unit 3 of the MMIC 2 in the third embodiment.

[0181] The external port 11 of this embodiment is arranged to face the input / output circuit 42. Thus, radio waves can be propagated between the external port 11 and the input / output circuit 42. In addition, in this embodiment, since the MMIC 2 is mounted on one surface 4a of the electric substrate 4 as described above, no substrate through hole SH is formed on the electric substrate 4 (see Fig. 20 ).

[0182] Except for the above-described contents, this embodiment is the same as the third embodiment. Also, in this embodiment, similarly to the third embodiment, the effects obtained by the configuration common to the third embodiment described above can be obtained.

[0183] In addition, the present embodiment is a modified example based on the third embodiment, but the present embodiment may be combined with any of the first, second, and fourth embodiments described above.

[0184] (Sixth Embodiment)

[0185] Next, a sixth embodiment will be described. In this embodiment, points different from the fifth embodiment described above will be mainly described.

[0186] like Fig.29 As shown, the MMIC 2 is not mounted on one surface 4 a of the electric substrate 4 but is mounted on the other surface 4 b of the electric substrate 4 .

[0187] In addition, in the electrical substrate 4, an input-output circuit 42 is formed on one surface 4a, and a connection wiring 41 is formed on the other surface 4b. In addition, a connection portion 43 is provided on the electrical substrate 4 to penetrate the electrical substrate 4 and electrically connect the connection wiring 41 and the input-output circuit 42. The connection portion 43 is composed of, for example, a through hole. The input-output circuit 42 and the connection wiring 41 are electrically connected via the connection portion 43.

[0188] Except for the above-described contents, this embodiment is the same as the fifth embodiment. Also, in this embodiment, similarly to the fifth embodiment, the effects obtained by the configuration common to the fifth embodiment described above can be obtained.

[0189] (Seventh Embodiment)

[0190] Next, a seventh embodiment will be described. In this embodiment, points different from the third embodiment described above will be mainly described.

[0191] like Fig.30 As shown, in this embodiment, the MMIC 2 is not mounted on the other surface 4b of the electrical substrate 4 but on the one surface 4a of the electrical substrate 4. That is, between the first block BC1 of the antenna device 1 and the one surface 4a of the electrical substrate 4, a gap for arranging the MMIC 2 is ensured by a plurality of spacers 5, and the MMIC 2 is arranged between the first block BC1 and the one surface 4a of the electrical substrate 4.

[0192] In this embodiment, as in the third embodiment, the external port 11 is arranged to face the input / output portion 3 of the MMIC 2. Thus, radio waves can be propagated between the external port 11 and the input / output portion 3 of the MMIC 2. However, in this embodiment, unlike the third embodiment, since the MMIC 2 is mounted on one side 4a of the electrical substrate 4 as described above, no substrate through hole SH is formed on the electrical substrate 4 (see Fig. 20 ).

[0193] Except for the above-described contents, this embodiment is the same as the third embodiment. Also, in this embodiment, similarly to the third embodiment, the effects obtained by the configuration common to the third embodiment described above can be obtained.

[0194] In addition, the present embodiment is a modified example based on the third embodiment, but the present embodiment may be combined with any of the first, second, and fourth embodiments described above.

[0195] (Eighth Embodiment)

[0196] Next, an eighth embodiment will be described. In this embodiment, points different from the sixth embodiment described above will be mainly described.

[0197] like Fig.31 As shown, in this embodiment, the spacer 5 in the sixth embodiment is not provided (see Fig.29The antenna device 1 of the present embodiment is arranged such that the first block BC1 is in contact with one surface 4a of the electric board 4 without the spacer 5 interposed therebetween. Furthermore, the MMIC 2 is mounted on the other surface 4b of the electric board 4.

[0198] In addition, an input-output circuit 42 is formed on one side 4a of the electric substrate 4, and a connection wiring 41 is formed on the other side 4b of the electric substrate 4. In addition, a connection portion 43 is provided on the electric substrate 4, which passes through the electric substrate 4 and electrically connects the connection wiring 41 and the input-output circuit 42. The connection portion 43 is composed of, for example, a through hole. The input-output circuit 42 and the connection wiring 41 are electrically connected via the connection portion 43.

[0199] Except for the above-described contents, this embodiment is the same as the sixth embodiment. Also, in this embodiment, similarly to the sixth embodiment, the effects obtained by the configuration common to the sixth embodiment described above can be obtained.

[0200] (Ninth Embodiment)

[0201] Next, a ninth embodiment will be described. In this embodiment, points different from the third embodiment described above will be mainly described.

[0202] like Fig.32 As shown, a structure for propagating radio waves transmitted and received by MMIC 2 can be established by arraying multiple antenna devices 1 into an array antenna 56. Such an array antenna 56 can be realized, for example, by coupling the MMIC 2 side of the first waveguide paths 13 in the multiple antenna devices 1 so that radio waves can be propagated between each of the first waveguide paths 13 of the antenna device 1 and the MMIC 2.

[0203] As described in the above-mentioned embodiment, the antenna device 1 of this scheme can be configured in a small size, so by using a plurality of antenna devices 1 to form an array antenna 56, a small array antenna 56 can be realized. In addition, since the input / output portion 3 of the MMIC 2 can be connected to a plurality of antenna openings 24, the gain of the array antenna 56 can be increased.

[0204] In addition, in each antenna element 1, the open space 26 (see Fig. 20 ) may be formed in the same manner as in the third embodiment, but in this embodiment, the open space 26 is not formed. Therefore, each antenna element 1 does not have an open space bottom surface 27 and an open space side surface 29 (see Fig. 20 ) In addition, the plurality of antenna openings 24 formed in each antenna device 1 of the present embodiment are formed in a rectangular shape extending in the tube length direction D1 in a plan view.

[0205] Except for the above-described contents, this embodiment is the same as the third embodiment. Also, in this embodiment, similarly to the third embodiment, the effects obtained by the configuration common to the third embodiment described above can be obtained.

[0206] In addition, the present embodiment is a modification example based on the third embodiment, but the present embodiment may be combined with any of the first, second, and fourth to eighth embodiments described above.

[0207] (Other embodiments)

[0208] (1) In the first embodiment described above, Figure 6 , Fig. 9 As shown in the figure, the opening peripheral wall surface 25 surrounding the antenna opening 24 is an inclined surface extending linearly in any of the sections perpendicular to the tube length direction D1 and the sections perpendicular to the tube width direction D3, but this is an example. The opening peripheral wall surface 25 may not be an inclined surface extending linearly in each of the above sections, but may be a curved surface that is convex or concavely curved so that the antenna opening 24 is wider toward one side in the tube height direction D2.

[0209] In addition, the opening peripheral wall surface 25 does not need to be inclined with respect to the tube height direction D2 in the cross section perpendicular to the tube length direction D1 and the cross section perpendicular to the tube width direction D3, and for example, it may be a surface along the tube height direction D2 in one of the two cross sections. Furthermore, it is also conceivable that the opening peripheral wall surface 25 is a vertical surface along the tube height direction D2 over the entire circumference of the antenna opening 24.

[0210] (2) In the first embodiment described above, Figure 6 , Fig. 9 As shown, the open space side surface 28 surrounding the open space 26 is a vertical surface along the tube height direction D2, but this is an example. For example, the open space side surface 28 may be inclined relative to the tube height direction D2 in such a manner that the open space 26 is wider as it approaches one side in the tube height direction D2. Further, in this case, the open space side surface 28 may be a planar inclined surface, or may be a curved surface that is convexly or concavely curved in one or both of the cross section perpendicular to the tube length direction D1 and the cross section perpendicular to the tube width direction D3.

[0211] (3) In the first embodiment described above, if Figure 3 As shown, the plurality of reflection suppression walls 30 are formed in rib shape, but this is an example. Various assumptions can be made as the shape of the reflection suppression wall 30. For example, any one or all of the plurality of reflection suppression walls 30 can be replaced with rod-shaped protrusions. In addition, various assumptions can be made as to the arrangement locations of the plurality of reflection suppression walls 30.

[0212] (4) In the first embodiment described above, if Figure 2 As shown, the antenna opening 24 is formed in an oval shape in a plan view, but may be formed in a shape other than the oval shape, such as a rectangular shape.

[0213] (5) In the first embodiment described above, if Figure 6 , Fig. 9 As shown in the figure, a small gap in the tube height direction D2 is formed between the one side wall portion 30a and the other side wall portion 30b constituting the reflection suppression wall 30, but this is an example. No gap may be formed between the one side wall portion 30a and the other side wall portion 30b, and the one side wall portion 30a and the other side wall portion 30b may be continuous in the tube height direction D2.

[0214] (6) In the first embodiment described above, if Figure 3 , Figure 4 As shown, the plurality of reflection suppression walls 30 are alternately arranged on one side and the other side in the tube width direction D3 in the second waveguide 21, but this is an example. For example, the reflection suppression walls 30 may be provided on both sides in the tube width direction D3 in the second waveguide 21 for each antenna opening 24 corresponding to the reflection suppression wall 30.

[0215] (7) In the fourth embodiment described above, if Fig.26 As shown in the figure, two choke grooves 531 and 532 are formed on the externally exposed surface 52, but the choke grooves 531 and 532 formed on the externally exposed surface 52 may be one.

[0216] (8) In the first embodiment described above, if Figure 3 As shown, five antenna openings 24 are arranged along the tube length direction D1 , but the number of antenna openings 24 may be less than four, or may be more than six.

[0217] (9) In the first embodiment and the like described above, the first waveguide 13 extends in a straight line, but the first waveguide 13 may extend in a curved manner at a portion away from the conversion space 17. In such a first waveguide 13, the tube length direction D1 is defined as a tangent direction of the central axis of the first waveguide 13. This is also true for the second waveguide 21.

[0218] (10) The antenna device 1 of each of the above-described embodiments is constituted by a structure ST in which two blocks BC1 and BC2 are stacked in the tube height direction D2 , but it does not need to be constituted by such a structure ST having a stacked structure.

[0219] (11) The MMIC 2 in each of the above-mentioned embodiments is configured to perform transmission and reception of radio waves, but this is an example, and it is also possible to perform only one of transmission and reception of radio waves. That is, the MMIC 2 only needs to be an electrical device that performs at least one of transmission and reception of radio waves. In addition, the antenna device 1 can also be applied to a device that performs transmission and reception of radio waves using a transceiver device other than the MMIC 2.

[0220] (12) In each of the spaces formed in the antenna device 1 of each of the above-mentioned embodiments, the corner R may be formed at the corner, or may not be formed. This is because it has no substantial effect on the characteristics of the antenna device 1. In addition, the above-mentioned spaces formed in the antenna device 1 are, for example, the external port 11, the first waveguide 13, the conversion space 17, the second waveguide 21, the antenna opening 24, and the open space 26.

[0221] (13) In each of the above-mentioned embodiments, the conversion space 17 of the polarization converter 16 is formed, for example, Figure 3 , Figure 5 The shape shown is an example. Various structures can be conceived as the conversion space 17. For example, the conversion space 17 can also be formed like a twisted waveguide that is twisted 90 degrees around an axis along the tube length direction D1 and has a rectangular cross section and extends in the tube length direction D1.

[0222] (14) In the first embodiment described above, if Figure 1 to Figure 3 As shown, the plurality of reflection suppression walls 30 are respectively arranged corresponding to the antenna openings 24, and the reflection suppression walls 30 are provided in the same number as the antenna openings 24, but this is an example. For example, it is also conceivable that any one of the first to fifth reflection suppression walls 301 to 305 is not provided. Therefore, the reflection suppression wall 30 may also be arranged corresponding to at least one of the plurality of antenna openings 241 to 245. That is, it is also conceivable that only one or two to four of the first to fifth reflection suppression walls 301 to 305 are provided.

[0223] (15) In addition, the present disclosure is not limited to the above-mentioned embodiments, and can be implemented in various modifications. In addition, the above-mentioned embodiments are not mutually unrelated embodiments, and can be appropriately combined except for the case where it is obvious that they cannot be combined.

[0224] In addition, in the above-mentioned embodiments, the elements constituting the embodiments are not necessarily necessary elements, except for the cases where they are specifically stated as necessary and the cases where they are clearly considered to be necessary in principle. In addition, in the above-mentioned embodiments, when the number, value, amount, range, and other numerical values ​​of the constituent elements of the embodiments are mentioned, they are not limited to the specific numbers, except for the cases where they are specifically stated as necessary and the cases where they are clearly limited to specific numbers in principle. In addition, in the above-mentioned embodiments, when the materials, shapes, positional relationships, etc. of the constituent elements are mentioned, they are not limited to the materials, shapes, positional relationships, etc., except for the cases where they are specifically stated and the cases where they are limited to specific materials, shapes, positional relationships, etc. in principle.

[0225] The present disclosure described above can be understood from other viewpoints, for example, as follows.

[0226] The array antenna 51 has:

[0227] A one-side antenna element 1a and another-side antenna element 1b as the antenna element; and

[0228] An externally exposed surface 52 is exposed to the external space toward the one side in the second direction.

[0229] The one side antenna opening 247 as the plurality of antenna openings provided in the one side antenna element is arranged in the third direction with respect to the other side antenna opening 248 as the plurality of antenna openings provided in the other side antenna element so as to sandwich the externally exposed surface therebetween.

[0230] The externally exposed surface is provided with choke slots 531 and 532 disposed between the plurality of one-side antenna openings and the plurality of other-side antenna openings in the third direction and extending toward the first direction.

[0231] The choke slot is provided with one or two choke slots arranged in parallel, and is configured to improve the isolation of radio waves between the plurality of one-side antenna openings and the plurality of other-side antenna openings.

Claims

1. An antenna device, characterized in that: have: A polarization conversion section having a conversion space for propagating radio waves; A first waveguide portion having a first waveguide path for propagating the radio wave, the first waveguide path being connected to the conversion space from one side in a first direction and extending from the conversion space to the one side in the first direction; as well as a second waveguide portion having a second waveguide tube and a plurality of antenna openings, wherein the second waveguide tube is connected to the conversion space from the other side in the first direction and extends from the conversion space to the other side in the first direction and propagates the radio waves; the plurality of antenna openings are connected to the second waveguide tube from one side in a second direction perpendicular to the first direction, are open to the external space toward the one side in the second direction, and are arranged along the first direction; The conversion space has one end disposed on the one side in the first direction and connected to the first waveguide and another end disposed on the other side in the first direction and connected to the second waveguide. The polarization conversion unit propagates the radio wave between the one end and the other end of the conversion space, and changes the vibration direction of the electric field of the radio wave in such a manner that the electric field of the radio wave vibrates along a third direction perpendicular to the first direction and the second direction at the one end of the conversion space and vibrates along the second direction at the other end of the conversion space. The first waveguide tube is formed into a cross-sectional shape extending in the second direction in a cross-sectional shape perpendicular to the first direction, that is, a tube cross-sectional shape. The second waveguide tube is formed into a cross-sectional shape extending in the third direction in the tube cross section.

2. The antenna device according to claim 1, characterized in that: The plurality of antenna openings are respectively formed as holes that expand toward the one side in the second direction.

3. The antenna device according to claim 1 or 2, characterized in that: The second waveguide portion has a plurality of opening peripheral surfaces provided on the one side in the second direction with respect to the plurality of antenna openings. The plurality of opening surrounding surfaces individually surround the plurality of antenna openings and are formed into a ring shape when viewed along the second direction, and are formed toward the inside of the ring shape.

4. The antenna device according to claim 1 or 2, characterized in that: The second waveguide portion has an opening peripheral surface provided on the one side in the second direction with respect to the plurality of antenna openings. The opening surrounding surface surrounds the plurality of antenna openings together and is formed into a ring shape when viewed along the second direction, and is formed toward the inside of the ring shape.

5. The antenna device according to claim 1 or 2, characterized in that: The second waveguide portion has at least one in-pipe protrusion, which is disposed in the second waveguide and protrudes from a wall surface of the second waveguide to suppress reflection of the radio wave in the second waveguide. The in-duct protrusion is arranged corresponding to at least one of the plurality of antenna openings.

6. The antenna device according to claim 5, characterized in that: The plurality of antenna openings are alternately arranged to be biased toward one side and the other side in the third direction relative to the central axis of the second waveguide extending along the first direction and are arranged along the first direction. The in-duct protrusion is arranged in the third direction on a side opposite to a side on which the antenna opening corresponding to the in-duct protrusion is arranged, with respect to the central axis of the second waveguide.

7. The antenna device according to claim 5, characterized in that: The in-tube protrusion at least partially falls within the range occupied by the antenna opening corresponding to the in-tube protrusion in the first direction, and is configured to be biased toward the other side in the first direction relative to the antenna opening corresponding to the in-tube protrusion.

8. The antenna device according to claim 5, characterized in that: The configuration of a certain in-tube protrusion included in at least one of the in-tube protrusions corresponding to a certain antenna opening included in the multiple antenna openings means that, when observed along the third direction, the certain antenna opening among the multiple antenna openings is configured closest to the certain in-tube protrusion.

9. The antenna device according to claim 1 or 2, characterized in that: The first waveguide propagates the radio wave between the conversion space and an electrical device that performs at least one of transmission and reception of the radio wave.

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