JP2012204975A - Waveguide slot antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveguide slot antenna which can reduce the occurrence of grating lobe even when a waveguide for radiating horizontal polarization and a waveguide for radiating vertical polarization are integrated with each other.SOLUTION: The waveguide slot antenna includes a plurality of first waveguides 1 formed by allowing a plurality of first slot elements 12a-12h for radiating horizontal polarization to extend in a direction inclined with respect to a tube axis, and a plurality of second waveguides 2 by allowing a plurality of second slot elements 22a-22h to extend in a direction parallel to the tube axis. The first waveguides 1 and the second waveguides 2 are alternatingly stacked one upon another in a direction orthogonal to the tube axis, and the second waveguides 2 are formed to have a U-shaped cross-section.

Description

  The present invention relates to a waveguide slot antenna.

  Slot antennas using waveguides include a slot antenna that radiates horizontal polarization and a slot antenna that radiates vertical polarization (see, for example, Patent Document 1). The slot antenna that radiates horizontal polarization and the slot antenna that radiates vertical polarization may be used independently, but both slot antennas may be used together in order to increase the amount of information obtained.

  As such a slot antenna, as shown in FIG. 8, a slot antenna 101 having a plurality of inclined slot elements 101a that radiates horizontally polarized waves and a slot antenna 102 having a plurality of horizontal slot elements 102a that radiates vertically polarized waves. Are combined and integrated.

JP 2000-36711 A

  However, when the slot antennas 101 and 102 that radiate horizontal polarization and vertical polarization are simply combined as described above, the radiation centers of the radio waves of horizontal polarization and vertical polarization are different, and a wide installation space is required. There is a problem that must be secured.

  In order to solve these problems, as shown in FIG. 9, a first waveguide 201 having a vertically long rectangular section having a plurality of inclined slot elements 201a and a horizontally long rectangular section having a plurality of horizontal slot elements 202a. It has been proposed to stack and integrate the second waveguide 202 alternately. However, in this case, the element spacing L1 between the first waveguides 201 adjacent to each other in the stacking direction and the element spacing L2 between the second waveguides 202 are larger than in the case of a single polarization slot antenna. This causes a problem that the grating lobe from which radio waves are radiated becomes large.

  The present invention has been made in view of the above problems, and even if a waveguide that radiates horizontal polarization and a waveguide that radiates vertical polarization are integrated, generation of grating lobes can be suppressed. An object of the present invention is to provide a waveguide slot antenna that can be used.

  (1) A waveguide slot antenna according to the present invention includes a first waveguide formed by extending a plurality of first slot elements that radiate horizontally polarized waves in a direction inclined with respect to a tube axis, and a vertically polarized wave A plurality of second waveguides formed by extending a plurality of second slot elements extending in a direction parallel to the tube axis, and the first waveguide and the second waveguide, The second waveguides are alternately stacked in a direction perpendicular to the tube axis, and the second waveguide is formed in a U-shaped cross section.

  According to the present invention, the second waveguides that are alternately stacked together with the first waveguide are formed in a U-shaped cross section, so that the second waveguide can be compared with a vertically long rectangular waveguide having the same in-tube wavelength. Since a waveguide can be made small, it can suppress that the element space | interval of the stacking direction becomes large. Therefore, even if the first waveguide that radiates horizontal polarization and the second waveguide that radiates vertical polarization are integrated, generation of grating lobes can be suppressed.

(2) Further, the waveguide slot antenna includes an element interval between two first waveguides adjacent to each other with the second waveguide interposed therebetween, and two adjacent ones with the first waveguide interposed therebetween. It is preferable that the element spacing of the second waveguide is set to a length of 0.8λ ₀ (λ ₀ is a free space wavelength of the used frequency) or less.
In this case, since each element interval of the first waveguide and the second waveguide can be set to an appropriate length, generation of grating lobes can be effectively suppressed.

(3) The first waveguide has a first feeding point at a central portion in the tube axis direction, and the two first slot elements adjacent to each other in the tube axis direction with the first feeding point interposed therebetween. It is preferable that they are inclined in the same direction at positions separated from the first feeding point by the same length.
In this case, an electric field is generated in the same direction in each of the two first slot elements adjacent to each other in the tube axis direction across the first feeding point. Therefore, by superposition of radio waves radiated from the first slot elements, The radiation intensity in the main beam direction can be increased.

(4) Further, in the waveguide slot antenna, two first waveguides adjacent to each other with the second waveguide interposed therebetween are fed with the same phase at the first feeding point, respectively. Among the first waveguides, the two adjacent first slot elements of one first waveguide and the two adjacent first slot elements of the other first waveguide are in the same direction. It is preferable to be inclined.
In this case, an electric field is generated in the same direction in each of the adjacent first slot elements in each of the two first waveguides fed in phase, so that the first slot elements of the first waveguides The radiation intensity in the main beam direction can be increased by superimposing the radio waves radiated from each.

(5) Further, in the waveguide slot antenna, two first waveguides adjacent to each other with the second waveguide interposed therebetween are fed in opposite phases at the first feeding point, Of the two first waveguides, the two adjacent first slot elements of one first waveguide and the two adjacent first slot elements of the other first waveguide are mutually connected. It is preferable to incline in the opposite direction.
In this case, an electric field is generated in the same direction in each of the adjacent first slot elements in each of the two first waveguides that are fed in opposite phases to each other. By superimposing the radio waves radiated from the slot elements, the radiation intensity in the main beam direction can be increased.

(6) The first waveguide has a first feeding slot element at one end in the tube axis direction, and the second waveguide has a second feeding slot element at the other end in the tube axis direction. And two rows are arranged so that one row of waveguide rows in which the first waveguide and the second waveguide are alternately stacked are symmetrical with each other across a line extending in the stacking direction It is preferable that
In this case, two rows of one row of waveguide rows in which the first waveguide and the second waveguide fed alternately from both ends in the tube axis direction are alternately arranged, and the two rows of waveguides are arranged. By arranging the lines in line symmetry, the peak direction of field emission can be made constant at all frequencies at the operating frequency without causing a shift in the peak direction of field emission due to the difference in frequency (difference in the tube wavelength). it can.

  According to the present invention, it is possible to suppress the occurrence of grating lobes even if the first waveguide that radiates horizontal polarization and the second waveguide that radiates vertical polarization are integrated.

1 is a perspective view of a waveguide slot antenna according to a first embodiment of the present invention. It is a front view of the waveguide slot antenna of FIG. It is a side view of the waveguide slot antenna of FIG. It is a front view of the waveguide slot antenna which concerns on the 2nd Embodiment of this invention. It is a front view of the waveguide slot antenna which concerns on the 3rd Embodiment of this invention. FIG. 6 is a right side view of the left waveguide row in FIG. 5. FIG. 6 is a left side view of the left waveguide row in FIG. 5. It is a perspective view of the conventional waveguide slot antenna. It is a perspective view of the conventional waveguide slot antenna.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a waveguide slot antenna according to the first embodiment of the present invention, and FIG. 2 is a front view of the waveguide slot antenna. In FIG. 1, this waveguide slot antenna is attached to, for example, a wing portion of an aircraft, and includes a plurality (four in this embodiment) of first waveguides 1 and a plurality (four in this embodiment). The second waveguide 2 is stacked and integrated alternately in a direction (vertical direction in FIG. 1) perpendicular to the tube axis. The first waveguide 1 and the second waveguide 2 use a plurality of frequencies in a predetermined frequency band (in this embodiment, 9.3 to 9.8 GHz) centered on the design frequency.

  The first waveguide 1 is formed in a rectangular cross section and has a plurality of first slot elements (tilted slot elements) 12a to 12h that radiate horizontally polarized waves. The first slot elements 12a to 12h are formed on the narrow wall surface 11a of the first waveguide 1 so as to extend in a direction inclined with respect to the tube axis.

  The second waveguide 2 is formed of a ridge waveguide having a U-shaped cross section, and has a plurality of second slot elements (horizontal slot elements) 22a to 22h that radiate vertically polarized waves. Each of the second slot elements 22a to 22h is formed on the wide wall surface 21a of the second waveguide 2 so as to extend in a direction parallel to the tube axis.

In FIG. 1, the element interval L1 between two first waveguides 1 adjacent to each other with the second waveguide 2 interposed therebetween, and the elements of two second waveguides 2 adjacent to each other with the first waveguide 1 interposed therebetween. distance L2 is set to each 0.8Ramuda ₀ less in length. Here, λ ₀ is the free space wavelength of the used frequency.

Specifically, the width D1 between the wide wall surfaces facing the stacking direction of the first waveguide 1 is 5 mm, and is set shorter than the width (10 mm) of the standard waveguide. Further, the width D2 between the narrow wall surfaces facing the stacking direction of the second waveguide 2 is 15 mm, the plate thickness t of the first waveguide 1 and the second waveguide 2 is 1 mm, and the free space wavelength λ ₀ is about Each is set to 31 mm. Thereby, the element intervals L1 and L2 are set to 22 mm (≈0.7λ ₀ ).

In FIG. 2, the first waveguide 1 has a first feeding point 13 to which power is supplied at the central portion in the tube axis direction. Two first slot elements 12d and 12e adjacent in the tube axis direction across the first feeding point 13 are inclined in the same direction at positions away from the first feeding point 13 by the same length. Specifically, each of the first slot elements 12d and 12e has a predetermined angle θ (with respect to the tube axis X1 of the first waveguide 1 with a position away from the first feeding point 13 by λ _g / 4, respectively. In this embodiment, it is inclined by 50 degrees). Here, λ _g is an in-tube wavelength of the operating frequency.

The first slot elements 12a to 12c on the one side (left side in FIG. 2) in the tube axis direction from the first slot element 12d are alternately reversed in the tube axis direction every predetermined length (λ _g / 2). It is arranged so as to be inclined by an inclination angle θ. The first slot elements 12f to 12h on the other side in the tube axis direction (right side in FIG. 2) than the first slot element 12e have a predetermined length (λ _g / 2) in the tube axis direction, like the one side in the tube axis direction. ) Are alternately inclined in the opposite direction by the inclination angle θ.

  Two first waveguides 1 that are adjacent to each other with the second waveguide 2 interposed therebetween are fed at opposite first phases at each first feeding point 13. Of the two first waveguides 1, the first slot elements 12d and 12e of one first waveguide 1 and the first slot elements 12d and 12e of the other first waveguide 1 are Are inclined in opposite directions. Accordingly, the first slot elements 12a to 12c and 12f to 12h of the one first waveguide 1, and the first slot elements 12a to 12c and 12f to 12h of the other first waveguide 1, Are inclined in opposite directions.

The 2nd waveguide 2 has the 2nd feeding point 23 where electric power is supplied in the central part of the direction of a tube axis. The two second slot elements 22d and 22e adjacent to each other in the tube axis direction across the second feeding point 23 are located at positions away from the second feeding point 23 by the same length, respectively. They are arranged in a state offset with respect to X2 in opposite directions. Specifically, each of the second slot elements 22d and 22e is arranged centering on a position away from the second feeding point 23 by λ _g / 4, and arranged symmetrically with respect to each other about the second feeding point 23. Has been.

The second slot elements 22a to 22c on one side (left side in FIG. 2) in the tube axis direction from the second slot element 22d are alternately reversed in the tube axis direction every predetermined length (λ _g / 2). Arranged in an offset state. The second slot elements 22f to 22h on the tube axis direction other side (right side in FIG. 2) than the second slot element 22e have a predetermined length (λ _g / 2) in the tube axis direction, like the tube axis direction one side. ) Are alternately offset in the opposite direction.

  Two second waveguides 2 adjacent to each other across the first waveguide 1 are fed in phase with each other at each second feeding point 23. Of these two second waveguides 2, the second slot elements 22d and 22e of one second waveguide 2 and the second slot elements 22d and 22e of the other second waveguide 2 are These are arranged in an offset state in the same direction. Accordingly, the second slot elements 22 a to 22 c and 22 f to 22 h of the one second waveguide 2, and the second slot elements 22 a to 22 c and 22 f to 22 h of the other second waveguide 2, Are arranged in an offset state in the same direction.

FIG. 3 is a side view of the waveguide slot antenna. In FIG. 3, the waveguide slot antenna includes a first feed path 3 for supplying power to each first waveguide 1 and a second feed path for supplying power to each second waveguide 2. 4 is further provided.
The first feeding path 3 is formed of, for example, a waveguide, and is disposed at the center in the tube axis direction on the back side of the waveguide slot antenna (see FIG. 1). The first power supply path 3 includes a power supply main path 31, two first branch paths 32 branched from the power supply main path 31, and four second branch paths branched from the first branch paths 32, respectively. 33.

  The power feed main path 31 is disposed at a substantially central portion in the stacking direction of the first waveguide 1, one end of which is connected to a power feed unit (not shown), and the other end is perpendicular to the stacking direction (in FIG. 3). (Horizontal direction). One end of each first branch path 32 extending in the stacking direction is connected to the other end of the power feeding main path 31. One end of two second branch paths 33 is connected to each first branch path 32. Each second branch path 33 extends in a direction parallel to the tube axis of the power feeding main path 31, and the other end is connected to the narrow wall surface 11 b of the first waveguide 1. As a result, electric power is fed from the feeding section to the central portion in the tube axis direction of the first waveguide 1 through the feeding main path 31, the first branch path 32, and the second branch path 33.

  The second feed path 4 is formed by, for example, a coaxial cable, and is disposed at the center in the tube axis direction on the back side of the waveguide slot antenna. The second power feed path 4 includes a power feed main path 41, two first branch paths 42 branched from the power feed main path 41, and four second branch paths branched from the first branch paths 42, respectively. 43.

  The power feed main path 41 is disposed at a substantially central portion in the stacking direction of the second waveguide 2, one end thereof is connected to a power feed unit (not shown), and the other end is perpendicular to the stacking direction (in FIG. 3). (Horizontal direction). One end of two first branch paths 42 is connected to the other end of the power feeding main path 41 via a branch connection portion 44. Each first branch path 42 extends in a direction perpendicular to the stacking direction (left-right direction in FIG. 3), and then bends at a right angle toward the second waveguide 2 side.

  One end of each of the two second branch paths 43 is connected to the other end of the first branch path 42 via a branch connection portion 45. Each second branch path 43 extends slightly in the stacking direction and then extends in a direction parallel to the tube axis of the power feed main path 41, and the other end is connected to the concave bottom surface 21 b of the second waveguide 2. Yes. As a result, electric power is fed from the feeding section to the central portion in the tube axis direction of the second waveguide 2 through the feeding main path 41, the first branch path 42, and the second branch path 43.

  As described above, according to the waveguide slot antenna according to the embodiment of the present invention, the second waveguide 2 that is alternately stacked with the first waveguide 1 is formed of a ridge waveguide having a U-shaped cross section, Since the second waveguide can be made smaller than a waveguide having a rectangular cross section having the same in-tube wavelength, it is possible to suppress the increase in the element intervals L1 and L2 in the stacking direction. Therefore, even if the first waveguide 1 that radiates horizontal polarization and the second waveguide 2 that radiates vertical polarization are integrated, generation of grating lobes can be suppressed.

Further, the element interval L1 between two first waveguides 1 adjacent to each other with the second waveguide 2 interposed therebetween, and the element interval L2 between two second waveguides 2 adjacent to each other with the first waveguide 1 interposed therebetween. Is set to a length of 0.8λ ₀ or less, the element intervals L1 and L2 can be set to appropriate lengths, and therefore generation of grating lobes can be effectively suppressed.

  In the first waveguide 1, the two first slot elements 12 d and 12 e adjacent in the tube axis direction across the first feeding point 13 are located at the same distance from the first feeding point 13. Since they are inclined in the same direction, electric fields are generated in the same direction in the two adjacent first slot elements 12d and 12e. Thereby, the radiation intensity in the main beam direction can be increased by superimposing the radio waves emitted from the first slot elements 12d and 12e.

  The adjacent first slot elements of one of the first waveguides 1 out of the two first waveguides 1 that are adjacent to each other with the second waveguide 2 interposed therebetween and are fed in opposite phases to each other. 12d and 12e and the adjacent first slot elements 12d and 12e of the other first waveguide 1 are inclined in opposite directions to each other. Electric fields are generated in the same direction in the adjacent first slot elements 12d and 12e. Thereby, the radiation intensity in the main beam direction can be increased by superimposing radio waves radiated from the first slot elements 12d and 12e of the first waveguides 1 respectively.

  The adjacent second slot elements of one second waveguide 2 out of the two second waveguides 2 that are adjacent to each other with the first waveguide 1 interposed therebetween and are fed in phase with each other. 22d and 22e and the adjacent second slot elements 22d and 22e of the other second waveguide 2 are arranged in an offset state in the same direction. In the adjacent second slot elements 22d and 22e, an electric field is generated in the same direction. Thereby, the radiation intensity in the main beam direction can be increased by superimposing the radio waves radiated from the second slot elements 22d and 22e of the second waveguides 2, respectively.

  Further, the first waveguide 1 and the second waveguide 2 can use a plurality of frequencies in a predetermined frequency band centered on the design frequency.

[Second Embodiment]
FIG. 4 is a front view of a waveguide slot antenna according to the second embodiment of the present invention. The main difference between this embodiment and the first embodiment is that the arrangement of the first slot elements in the two adjacent first waveguides is different, and in the two adjacent second waveguides. The arrangement of the second slot elements is different.

  In the present embodiment, two first waveguides 1 that are adjacent to each other with the second waveguide 2 interposed therebetween are fed at the first feeding point 13 with the same phase. Of the two first waveguides 1, the first slot elements 12d and 12e of one first waveguide 1 and the first slot elements 12d and 12e of the other first waveguide 1 are , Each inclined in the same direction. Accordingly, the first slot elements 12a to 12c and 12f to 12h of the one first waveguide 1, and the first slot elements 12a to 12c and 12f to 12h of the other first waveguide 1, Are inclined in the same direction.

  Two second waveguides 2 that are adjacent to each other with the first waveguide 1 interposed therebetween are fed at opposite phase with each other at each second feeding point 23. Of these two second waveguides 2, the second slot elements 22d and 22e of one second waveguide 2 and the second slot elements 22d and 22e of the other second waveguide 2 are These are arranged in a state offset from each other in opposite directions. Accordingly, the second slot elements 22 a to 22 c and 22 f to 22 h of the one second waveguide 2, and the second slot elements 22 a to 22 c and 22 f to 22 h of the other second waveguide 2, Are arranged in a state offset from each other in opposite directions.

  As described above, in the waveguide slot antenna according to the present embodiment, the adjacent first slot elements of one of the first waveguides 1 out of the two first waveguides 1 fed in phase with each other. 12d and 12e and the adjacent first slot elements 12d and 12e of the other first waveguide 1 are inclined in the same direction, so that the adjacent first waveguides 1 are adjacent to each other. Electric fields are generated in the same direction in the first slot elements 12d and 12e. Thereby, the radiation intensity in the main beam direction can be increased by superimposing radio waves radiated from the first slot elements 12d and 12e of the first waveguides 1 respectively.

  The adjacent second slot elements of one second waveguide 2 out of the two second waveguides 2 that are adjacent to each other with the first waveguide 1 interposed therebetween and are fed in opposite phases to each other. 22d and 22e and the adjacent second slot elements 22d and 22e of the other second waveguide 2 are arranged in a state where they are offset in opposite directions to each other. In each of the adjacent second slot elements 22d and 22e, an electric field is generated in the same direction. Thereby, the radiation intensity in the main beam direction can be increased by superimposing the radio waves radiated from the second slot elements 22d and 22e of the second waveguides 2, respectively.

[Third Embodiment]
FIG. 5 is a front view of a waveguide slot antenna according to the third embodiment of the present invention. In FIG. 5, the waveguide slot antenna of the present embodiment has a virtual line in which one row of waveguide rows 5 in which the first waveguides 1 and the second waveguides 2 are alternately stacked extends in the stacking direction. Two rows are arranged so as to be line-symmetric with respect to each other with C interposed therebetween.

On the narrow wall surface 11 a of the first waveguide 1, first slot elements 12 a to 12 h are arranged so as to alternately incline in the opposite direction every predetermined length (λ _g / 2) in the tube axis direction. Yes. Of the two first waveguides 1 that are adjacent to each other with the second waveguide 2 interposed therebetween, the first slot elements 12 a to 12 h of one first waveguide 1 and the other first waveguide 1. The first slot elements 12a to 12h are inclined in the same direction.

On the wide wall surface 21 a of the second waveguide 2, second slot elements 22 a to 22 h are arranged in a state of being alternately offset in the opposite direction every predetermined length (λ _g / 2) in the tube axis direction. Yes. Of the two second waveguides 2 adjacent to each other across the first waveguide 1, the second slot elements 22 a to 22 h of one second waveguide 2 and the other second waveguide 2. The second slot elements 22a to 22h are arranged in an offset state in the same direction.

Each waveguide line 5 includes a first feeding path 7 for supplying power to the first waveguide 1 and a second feeding path 8 for supplying power to each second waveguide 2. ing.
The first feeding path 7 and the second feeding path 8 are formed by, for example, waveguides, and the first feeding path 7 is provided at one end in the tube axis direction on the back side of the waveguide row 5 in the other direction of the tube axis. The 2nd electric supply path 8 is each arrange | positioned at the edge part.

  FIG. 6 is a right side view of the left waveguide row 5 in FIG. In FIG. 6, the first power supply path 7 extends in the stacking direction of the first waveguide 1, and one end thereof is connected to a power supply unit (not shown). The first feeding path 7 is connected to the narrow wall surface 11b of each first waveguide 1 at four locations in the longitudinal direction. As a result, power is fed from the feeding section to the end portion in the tube axis direction of the first waveguide 1 through the first feeding path 7.

  FIG. 7 is a left side view of the left waveguide row 5 in FIG. In FIG. 7, the second power supply path 8 includes a power supply main path 81 and four branch paths 82 branched from the power supply main path 81. The power feeding main path 81 extends in the stacking direction of the second waveguide 2 and one end thereof is connected to a power feeding unit (not shown). One end of each branch path 82 is connected to the power feeding main path 81. The other end of each branch path 82 extends in a direction perpendicular to the main feeding path 81 and is connected to the concave bottom surface 21 b of the second waveguide 2. As a result, electric power is fed from the feeding section to the end portion in the tube axis direction of the second waveguide 2 through the feeding main path 81 and the branch path 82.

  In FIG. 5, the first waveguide 1 has a first feed slot element 14 at one end in the tube axis direction. The first power supply slot 14 is formed at a connection location with the first power supply path 7 on the narrow wall surface 11 b of the first waveguide 1. The first feeding slot elements 14 of the two first waveguides 1 adjacent to each other with the second waveguide 2 interposed therebetween are fed with opposite phases. Therefore, each of the first feeding slot elements 14 of the two first waveguides 1 feeds the tube axis X1 so that power is fed in the same phase toward the other end side of the first waveguide 1 in the tube axis direction. Are inclined in opposite directions.

  Each second waveguide 2 has a second feeding slot element 24 at the other end in the tube axis direction. The second power supply slot 24 is formed at a connection location with the branch path 82 of the second power supply path 8 on the concave bottom surface 21 b of the second waveguide 2. The second feed slot elements 24 of the two second waveguides 2 adjacent to each other with the first waveguide 1 interposed therebetween are fed with phases opposite to each other. For this reason, the second feeding slot elements 24 of the two second waveguides 2 are connected to the tube axis X2 so that power is fed in the same phase toward one end side of the second waveguide 2 in the tube axis direction. In contrast, they are inclined in opposite directions.

  As described above, in the waveguide slot antenna according to the present embodiment, one row of waveguide rows in which the first waveguide 1 and the second waveguide 2 that are fed from both ends in the tube axis direction are alternately stacked. 5 are arranged in two rows, and the two waveguide rows are arranged in line symmetry, so that there is no deviation in the peak direction of field emission due to the difference in frequency (difference in the guide wavelength). The field emission peak direction can be made constant at all frequencies.

[Other variations]
The embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

For example, the number of stacked first waveguides 1 and second waveguides 2 and the number of first slot elements 12a to 12h and second slot elements 22a to 22h in each of the above embodiments can be arbitrarily changed. .
In the first and second embodiments, the first feeding points 13 of the first waveguide 1 and the second feeding points 23 of the second waveguide 2 that are adjacent to each other in the stacking direction are the same. You may make it feed with a phase or a reverse phase.

  Furthermore, in 1st Embodiment, you may make it form the 1st electric power feeding path 3 and the 2nd electric power feeding path 4 with a waveguide or a coaxial cable.

DESCRIPTION OF SYMBOLS 1 1st waveguide 2 2nd waveguide 5 Waveguide row | line | columns 12a-12h 1st slot element 13 1st feed point 14 1st feed slot elements 22a-22h 2nd slot element 23 2nd feed point 24 2nd Feed slot element

Claims (6)

A first waveguide formed by extending a plurality of first slot elements radiating horizontally polarized waves in a direction inclined with respect to a tube axis;
A plurality of second waveguides formed by extending a plurality of second slot elements that radiate vertically polarized waves in a direction parallel to the tube axis,
The first waveguide and the second waveguide are alternately stacked in a direction perpendicular to the tube axis,
A waveguide slot antenna, wherein the second waveguide has a U-shaped cross section. An element interval between two first waveguides adjacent to each other across the second waveguide and an element interval between two adjacent second waveguides across the first waveguide are each 0. The waveguide slot antenna according to claim 1, wherein the waveguide slot antenna is set to a length equal to or less than .8λ ₀ (λ ₀ is a free space wavelength of a use frequency). The first waveguide has a first feeding point at a central portion in the tube axis direction,
The two first slot elements adjacent to each other in the tube axis direction across the first feeding point are inclined in the same direction at positions away from the first feeding point by the same length. A waveguide slot antenna as described. Two first waveguides adjacent to each other across the second waveguide are fed in phase with each other at the first feeding point,
Of the two first waveguides, the two adjacent first slot elements of one first waveguide and the two adjacent first slot elements of the other first waveguide are: The waveguide slot antenna according to claim 3, wherein the waveguide slot antenna is inclined in the same direction. Two first waveguides adjacent to each other across the second waveguide are fed in opposite phases at the first feeding point,
Of the two first waveguides, the two adjacent first slot elements of one first waveguide and the two adjacent first slot elements of the other first waveguide are: The waveguide slot antenna according to claim 3, wherein the waveguide slot antennas are inclined in directions opposite to each other. The first waveguide has a first feeding slot element at one end in the tube axis direction,
The second waveguide has a second feeding slot element at the other end in the tube axis direction,
Two rows of waveguide rows in which the first waveguide and the second waveguide are alternately stacked are arranged so as to be symmetrical with respect to each other across a line extending in the stacking direction. Item 3. The waveguide slot antenna according to Item 1 or 2.

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