JP2015171085A - Non-directional antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-directional antenna capable of improving antenna performance.SOLUTION: The non-directional antenna has plural antenna planes disposed on plural planes, and includes plural antenna parts formed with plural slots for radiating polarized wave of a predetermined frequency band in the respective antenna planes. The non-directional antenna has protruding parts which protrude outward relative to the antenna part to prevent radiation of polarized wave in the vicinity direction which bisects an angle which is formed by a front direction of the slot formed in one plane in the neighboring antenna planes and a front direction of the slot formed in the other plane.

Description

  The present invention relates to an omnidirectional antenna.

  A horizontally polarized omnidirectional antenna generally employs a multi-plane combining method using a plurality of antennas. As such a horizontally polarized wave omnidirectional antenna, an antenna using a waveguide slot antenna is known (see, for example, Patent Document 1).

JP 2007-59959 A (see FIGS. 1 and 2)

However, since the horizontally polarized omnidirectional antenna described in Patent Document 1 uses a plurality of waveguides for multi-side synthesis, there is a problem that the multi-side synthesized antenna portion is enlarged. In particular, a horizontally polarized omnidirectional antenna used in the millimeter wave band is required to reduce the size of the antenna unit as the wavelength becomes smaller.
Therefore, the present applicant has a plurality of antenna surfaces arranged in multiple planes, slots formed on each of these antenna surfaces to radiate horizontally polarized waves, and a plurality of waveguides respectively communicating with the slots on each antenna surface. A horizontally polarized omnidirectional antenna having a single polyhedron has already been proposed (Japanese Patent Application No. 2012-196414, hereinafter referred to as “prior application invention”).

However, in the horizontally polarized omnidirectional antenna of the prior invention, there is a problem that the omnidirectional deviation (difference between the maximum gain and the minimum gain) becomes large in the horizontal plane directivity by a plurality of antenna surfaces. There was a problem of being strongly affected by cross polarization simultaneously with polarization.
The present invention has been made in view of the above problems, and an object thereof is to provide an omnidirectional antenna capable of improving antenna performance.

  The present invention is an omnidirectional antenna having a plurality of antenna faces arranged in multiple faces, each antenna face having an antenna portion formed with a slot for radiating polarized waves in a predetermined frequency band, Polarization is radiated in the vicinity of a direction that bisects the angle formed by the front direction of the slot formed on one of the adjacent antenna surfaces and the front direction of the slot formed on the other side. In order to suppress this, the antenna unit is an omnidirectional antenna including a protruding portion that protrudes outward from the antenna portion.

From another viewpoint, the present invention communicates with a plurality of antenna surfaces arranged in multiple planes, slots formed on the antenna surfaces and radiating polarized waves in a predetermined frequency band, and slots on the antenna surfaces. An omnidirectional antenna including a polyhedron having a plurality of waveguides, wherein the waveguide extends in one direction along the antenna surface inside the polyhedron, and the one-way The distance L from the other end in the one direction of the waveguide to the center point of the slot closest to the other end is set so as to satisfy the following formula: It is a directional antenna.
L = (λ _g / 4) + n × (λ _g / 2)
Here, λ _g is the wavelength in the waveguide of the design center frequency in the frequency band, and n is an integer of 1 or more.

  According to the present invention, the antenna performance of an omnidirectional antenna can be improved.

1 is a perspective view showing an omnidirectional antenna according to a first embodiment of the present invention. It is sectional drawing which shows an omnidirectional antenna. The radome is shown, (a) is a top view, (b) is an AA arrow sectional view of (a), (c) is a bottom view. The distribution part is shown, (a) is a top view, (b) is BB arrow sectional drawing of (a), (c) is a bottom view. The 1st division body of the antenna part is shown, (a) is a front view, (b) is a bottom view. The 2nd division body of the antenna part is shown, (a) is a top view, (b) is a front view, (c) is a bottom view. The 3rd division body of the antenna part is shown, (a) is a front view, (b) is a bottom view. FIG. 8 is an enlarged end view taken along the line CC in FIG. 7. It is explanatory drawing which shows the relationship between the formation position of the slot in each branch direction, and a phase. It is a figure which shows the horizontal surface directivity of the conventional omnidirectional antenna. It is a figure which shows the horizontal surface directivity of the omnidirectional antenna of 1st Embodiment. It is sectional drawing which shows the modification of a protrusion part. It is sectional drawing which shows the other modification of a protrusion part. It is sectional drawing which shows the other modification of a protrusion part. It is sectional drawing which shows the other modification of a protrusion part. This is the horizontal plane directivity of the omnidirectional antenna when L = λ _g / 4. This is the horizontal plane directivity of the omnidirectional antenna of the first embodiment with L = 5λ _g / 4. This is the horizontal plane directivity of the omnidirectional antenna when L = 3λ _g / 4. The horizontal plane directivity of the omnidirectional antenna when L = 7λ _g / 4. VSWR of an omnidirectional antenna with L = 5λ _g / 4 and L = 13λ _g / 4. It is sectional drawing of the omnidirectional antenna which concerns on 2nd Embodiment of this invention. It is sectional drawing of the omnidirectional antenna which concerns on the modification of 2nd Embodiment of this invention.

[Description of Embodiment of the Present Invention]
First, the contents of the embodiment of the present invention will be listed and described.
(1) An omnidirectional antenna according to an embodiment of the present invention has a plurality of antenna surfaces arranged in multiple planes, and each antenna surface is formed with a slot that radiates polarized waves in a predetermined frequency band. The angle formed by the front direction of the slot formed on one of the adjacent antenna surfaces and the front direction of the slot formed on the other side In order to prevent the polarized light from being radiated in the vicinity of the dividing direction, a protruding portion provided to protrude outward from the antenna portion is provided.
Here, the “front direction” of a slot is a direction extending perpendicularly to the antenna surface from the center point of the slot toward the outside of the antenna surface on which the slot is formed. Further, “near the bisecting direction” means not only the direction that coincides with the bisecting direction but also the direction that is slightly deviated from the bisecting direction.

  According to the above omnidirectional antenna, the projections provided in the antenna section are offset from the slots formed on the adjacent antenna surfaces in the vicinity of the direction that bisects the angle formed by the front directions of these slots. Waves can be prevented from being emitted. Thereby, compared with the conventional omnidirectional antenna, an omnidirectional deviation can be suppressed and antenna performance can be improved.

(2) It is preferable that the protruding portion of (1) is provided to protrude outward with respect to at least one of the adjacent antenna surfaces.
In this case, the omnidirectional deviation can be effectively suppressed.

(3) It is preferable that the slots of (1) or (2) are formed one by one on each antenna surface in a cross section perpendicular to the plurality of antenna surfaces of the antenna unit.
In this case, in the cross section perpendicular to the plurality of antenna surfaces of the antenna unit, the entire antenna can be reduced in size compared to the case where a plurality of slots are formed on each antenna surface. The beam width of the polarized wave radiated from each slot becomes wider. For this reason, polarized waves are strongly radiated in the vicinity of the direction that bisects the angle formed by the front directions of the slots formed on the adjacent antenna surfaces, and the omnidirectional deviation is further increased. Therefore, the omnidirectional deviation, which is particularly problematic when one slot is formed on each antenna surface, can be effectively suppressed by the protruding portion provided in the antenna portion.

(4) The antenna unit according to any one of (1) to (3) includes a plurality of the antenna surfaces and a plurality of waveguides formed therein so as to communicate with the slots of the antenna surfaces, respectively. Preferably, the protrusion is provided so as to protrude outward with respect to the polyhedron.
Generally, as a method for suppressing the omnidirectional deviation, it is conceivable to narrow the interval between adjacent antenna elements. When this method is applied to a polyhedron in which slots are formed on a plurality of antenna surfaces, the distance between adjacent slots (antenna elements) formed on both antenna surfaces is reduced by reducing the width of adjacent antenna surfaces. can do.
However, in the case of a polyhedron having a plurality of waveguides, if the width of the antenna surface is shortened, the polyhedron becomes too small as a whole, and a plurality of waveguides cannot be formed therein. On the other hand, the structure in which the protruding portion is provided so as to protrude outward from the polyhedron can suppress the omnidirectional deviation while securing a space for forming the waveguide inside the polyhedron. Therefore, the structure in which the protrusion is provided on the polyhedron to suppress the omnidirectional deviation is further effective in a small omnidirectional antenna in which a plurality of waveguides are formed inside the polyhedron.

(5) The number of antenna surfaces in (4) is preferably four.
In this case, since the polyhedron needs a space for forming four waveguides corresponding to the slots of each antenna surface, if the width of the antenna surface is shortened by the above-described general method, the polyhedron is entirely It becomes too small, and it becomes impossible to form four waveguides in the inside. On the other hand, the structure in which the protruding portion that suppresses the omnidirectional deviation protrudes outwardly from the polyhedron provides the omnidirectional deviation while securing a space for forming four waveguides inside the polyhedron. Can be suppressed. Therefore, the structure in which the protrusion is provided on the polyhedron to suppress the omnidirectional deviation is further effective when applied to an omnidirectional antenna in which four antenna surfaces are formed inside the polyhedron.

(6) In the omnidirectional antenna of (4) or (5), it is preferable that the polarization is horizontal polarization.
In general, an omnidirectional antenna that radiates horizontally polarized waves has a more complicated structure for making it omnidirectional than an omnidirectional antenna that radiates vertically polarized waves. It is necessary to make it as small as possible. Therefore, if an omnidirectional antenna including a polyhedron having a waveguide communicating with slots on a plurality of antenna surfaces as described in (4) above is applied, the antenna structure can be reduced in size. However, in this case, if the width of the antenna surface is shortened by the above-described general method, the polyhedron becomes too small as a whole, and a waveguide cannot be formed inside the polyhedron. On the other hand, the structure in which the protruding portion that suppresses the omnidirectional deviation protrudes outward from the polyhedron can suppress the omnidirectional deviation while securing a space for forming the waveguide in the polyhedron. it can. Therefore, the structure in which the protrusion is provided on the polyhedron to suppress the omnidirectional deviation is further effective when applied to an omnidirectional antenna that radiates horizontally polarized waves.

(7) The omnidirectional antenna according to any one of (4) to (6) preferably has a frequency band of 10 GHz or more.
In this case, it is necessary to make the antenna structure as small as possible in order to reduce transmission loss. Therefore, if an omnidirectional antenna including a polyhedron having a waveguide communicating with slots on a plurality of antenna surfaces as described in (4) above is applied, the antenna structure can be reduced in size. However, in this case, if the width of the antenna surface is shortened by the above-described general method, the polyhedron becomes too small as a whole, and a waveguide cannot be formed inside the polyhedron. On the other hand, the structure in which the projecting portion that suppresses the omnidirectional deviation protrudes outward from the polyhedron suppresses the omnidirectional deviation while securing a space for forming the waveguide inside the polyhedron. be able to. Therefore, the structure in which the protrusion is provided on the polyhedron to suppress the omnidirectional deviation is further effective when applied to an omnidirectional antenna having a frequency band of 10 GHz or more.

(8) The antenna unit according to any one of (1) to (7) includes a single polyhedron having the plurality of antenna surfaces and a plurality of waveguides respectively communicating with the slots of the antenna surfaces. The waveguide is formed to extend in one direction along the antenna surface inside the polyhedron, and is fed from one end in the one direction, and the other end in the one direction of the waveguide. To the center point of the slot closest to the other end is preferably set so as to satisfy the following expression.
L = (λ _g / 4) + n × (λ _g / 2)
Here, λ _g is the wavelength in the waveguide of the design center frequency in the frequency band, and n is an integer of 1 or more.
In this case, by setting the distance L from the other end of the waveguide to the center point of the slot closest to the other end so as to satisfy the above formula, the crossing in directivity compared to the conventional omnidirectional antenna The influence of polarization can be reduced. That is, as a result of earnest research, the present inventor has found that the distance L from the other end of the waveguide to the center point of the slot closest to the other end is deeply related to the influence of cross polarization on directivity. And the embodiment of the invention according to the above (8) is completed based on such knowledge.

(9) It is preferable that the n in (8) is an even number.
In this case, the influence of cross polarization on directivity can be reduced without changing the slot formation position.

(10) The n in (9) is more preferably 2.
In this case, the influence of cross polarization on directivity can be further effectively reduced without narrowing the usable frequency band.

(11) An omnidirectional antenna according to an embodiment of the present invention from another viewpoint includes a plurality of antenna surfaces arranged in multiple planes, and a slot that is formed on each antenna surface and emits polarized waves in a predetermined frequency band. And a plurality of waveguides respectively communicating with the slots of each antenna surface, the omnidirectional antenna having a polyhedron, wherein the waveguide is unidirectional along the antenna surface inside the polyhedron The distance L from the other end in the one direction of the waveguide to the center point of the slot closest to the other end is as follows: It is set to satisfy the following formula.
L = (λ _g / 4) + n × (λ _g / 2)
Here, λ _g is the wavelength in the waveguide of the design center frequency in the frequency band, and n is an integer of 1 or more.

According to this omnidirectional antenna, the distance L from the other end of the waveguide to the center point of the slot closest to the other end is set so as to satisfy the above formula, so that it can be compared with the conventional omnidirectional antenna. Thus, it is possible to reduce the influence of cross polarization on directivity and improve the antenna performance.
That is, as a result of earnest research, the inventor of the present application shows that the distance L from the other end of the waveguide to the center point of the slot closest to the other end is deeply related to the influence of cross polarization on directivity. And the embodiment of the invention according to the above (11) is completed based on such knowledge.

[Details of the embodiment of the present invention]
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a perspective view showing an omnidirectional antenna according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the omnidirectional antenna.
As shown in FIG.1 and FIG.2, the omnidirectional antenna 1 is used as a mobile antenna which transmits the video data image | photographed, for example with the high-definition television camera. The omnidirectional antenna 1 includes a distribution unit 2 that distributes input power, an antenna unit 3 that radiates horizontal polarization in a predetermined frequency band, and a radome 4 that covers the antenna unit 3. The frequency band is set to a millimeter wave band of 10 GHz or more, more preferably 30 GHz or more. In this embodiment, the center frequency band is set to 41.5 GHz (wavelength λ = 7.3 mm).

<Radome>
The radome 4 includes a radome main body 41 formed in a cylindrical shape with a synthetic resin material (for example, PTFE), and a metal annular fixing plate 42. The radome main body 41 includes a cylindrical portion 43 that covers the entire antenna portion 3 and a protrusion 12 (described later) of the distributing portion 2, and an annular portion 44 that is integrally formed at the lower end of the cylindrical portion 43. A fixed plate 42 is placed on the upper surface of the annular portion 44.

  3A and 3B show the radome 4, wherein FIG. 3A is a plan view, FIG. 3B is a cross-sectional view taken along the line A-A in FIG. 3A, and FIG. As shown in FIGS. 3A to 3C, four cylindrical nut portions 46 having screw holes on the inner periphery protrude from the lower surface of the fixed plate 42. In the annular portion 44 of the radome body 41, four connection holes 45 into which the nut portions 46 of the fixing plate 42 are inserted are formed so as to penetrate in the vertical direction. A screw (not shown) penetrating through a connecting hole 19 (see FIG. 4C) of the distribution unit 2 which will be described later is screwed into the nut portion 46 inserted into each connecting hole 45. Thereby, the radome 4 is fixed to the distribution part 2.

<Distributor>
4A and 4B show the distribution unit 2. FIG. 4A is a plan view, FIG. 4B is a cross-sectional view taken along the line BB in FIG. 4A, and FIG.
As shown in FIGS. 4A to 4C, the distribution unit 2 is separated from the antenna unit 3, and a columnar base 11 that is detachably connected to the antenna unit 3. And a cylindrical protrusion 12 protruding above the base 11. The base body 11 and the projecting body 12 are made of metal. An input waveguide 13 having a rectangular cross section extending in the vertical direction is formed at the center of the base 11 and the protrusion 12. The protrusion 12 is formed with a cross-shaped distribution waveguide 14 that diverges radially into four horizontal directions E1 to E4 about the road axis Z above the input waveguide 13. The projecting body 12 is formed with a connection path 10 having a square cross section extending in the vertical direction between the input waveguide 13 and the distribution waveguide 14.

  As shown in FIG. 4 (a), the input waveguide 13 has a part of the center line S extending in the long side direction of the cross-sectional shape, and two adjacent branch directions E1 and E2 of the distribution waveguide 14. Between the two branch directions E1 and E2 and inclined at a predetermined angle (45 ° in the present embodiment). As shown in FIGS. 4B and 4C, the lower end of the input waveguide 13 is opened at the center of the bottom surface of the base 11, and a waveguide (not shown) is connected to the opening. Electric power is input.

As shown in FIGS. 4A and 4B, the distribution waveguide 14 is formed on the upper surface (end surface) of the protrusion 12, and is formed in the same cross-sectional shape as the connection path 10 immediately above the connection path 10. Center recess 14e (cross-hatched portions in FIGS. 4A and 4B), and first to fourth recesses 14a to 14d formed extending from the center recess 14e in the branching directions E1 to E4, respectively. It is constituted by.
As shown in FIG. 4B, the connection path 10 is formed in the projecting body 12 directly below the central recess 14e of the distribution waveguide 14 and above the input waveguide 13. The distribution waveguide 14 is connected. Further, the connection path 10 is formed so as to circumscribe the input waveguide 13 in the plan view of FIG. 4A, and between the connection path 10 and the input waveguide 13 in the side view of FIG. Are stepped. Thereby, the connection path 10 functions as a transformer for matching impedance between the input waveguide 13 and the distribution waveguide 14.

  As shown in FIGS. 2 and 5B, the upper opening of the distribution waveguide 14 is formed at the outer end in the radial direction of the first to fourth recesses 14 a to 14 d by the lower surface 31 e of the first divided body 31 of the antenna unit 3. The four parts are covered and are connected to the first output waveguides 31a to 31d (described later) of the first divided body 31 at these four places.

  As shown in FIG. 4C, two positioning pins 15 for projecting the connection position of the waveguide with respect to the base body 11 project from the bottom surface of the base body 11 of the distributor 2. As shown in FIGS. 4A and 4B, a pair of positioning pins 16 for projecting the mounting position of the radome 4 with respect to the base body 11 protrude from the upper surface of the base body 11. On the upper surface of the projecting body 12, a pair of positioning pins 17 for projecting the connection position of the projecting body 12 with respect to the antenna unit 3 are provided. The distributor 2 is formed with a pair of connecting holes 18 penetrating in the vertical direction and four connecting holes 19 penetrating in the vertical direction.

With the above configuration, the E waveguide branch of the magic T and the H plane branch of the magic T are configured in the distribution unit 2 by the input waveguide 13 and the cross-shaped distribution waveguide 14 orthogonal to the input waveguide 13. 4 can be distributed in the horizontal direction (the direction orthogonal to the path axis Z of the input waveguide 13) from the central portion of the distribution waveguide 14.
At that time, a part of the center line S of the input waveguide 13 is inclined by 45 ° with respect to two predetermined adjacent branch directions E1 and E2 of the distribution waveguide 14 as shown in FIG. Therefore, the first system that distributes two from the central portion of the distribution waveguide 14 in the two predetermined adjacent branch directions E1 and E2 and the other two adjacent branches from the central portion of the distribution waveguide 14 When the system is divided into the second system that distributes in two directions E3 and E4, each system is divided into two with a phase difference of 0 ° / 180 ° by the E-plane branch of the magic T. Therefore, the branch directions E1 and E2 and the branch directions E3 and E4 in the same system are out of phase with each other, and the two adjacent branch directions E1 and E4 and the branch directions E2 and E3 between different systems are They are in phase with each other (see also FIG. 9).

<Antenna part>
As shown in FIG. 2, the antenna unit 3 includes first to third divided bodies 31 to 33 that are divided into three in the axial direction. FIG. 5 shows the first divided body 31 of the antenna unit 3, where (a) is a front view and (b) is a bottom view.
<First division>
As shown in FIGS. 2 and 5, the first divided body 31 is formed of a thin disk, and the lower surface 31 e is a distribution waveguide on the upper surface of the projecting body 12 of the distribution unit 2 as described above. It arrange | positions so that 14 upper opening may be covered. The first divided body 31 has four first output waveguides 31a to 31d having a rectangular cross section composed of first straight path portions penetratingly formed so as to extend straight in the thickness direction (vertical direction). doing.

  As shown in FIG. 5B, of the four first output waveguides 31 a to 31 d, the two first output waveguides 31 a and 31 c are mutually connected with the center line X <b> 1 of the first divided body 31 interposed therebetween. The other two first output waveguides 31b and 31d are formed symmetrically with respect to each other across the center line Y1 of the first divided body 31 orthogonal to the center line X1. The single output waveguides 31a and 31c each have a cross-sectional shape that is symmetrical with respect to the center line Y1, and the single output waveguides 31b and 31d each have a cross-sectional shape that is the center line X1. It is formed symmetrically across the. Furthermore, the cross-sectional shapes of the first output waveguides 31a to 31d are all the same size.

  A prismatic adjustment element 5 that adjusts a power distribution ratio to each of the first output waveguides 31 a to 31 d is integrally provided on the lower surface 31 e of the first divided body 31. The adjusting element 5 is disposed in the central portion of the distribution waveguide 14 in a state where the first divided body 31 is disposed on the upper surface of the protruding body 12 of the distribution portion 2, and the central recess 14 e of the distribution waveguide 14 and the connection path 10. Has been inserted. The horizontal cross section of the adjustment element 5 is formed, for example, in a square shape, and each side surface of the adjustment element 5 is arranged facing the cross direction of the distribution waveguide 14 (the branch directions E1 to E4 in FIG. 4A). It is like that.

  As shown in FIG. 5B, the first divided body 31 has two positioning holes 31f formed therethrough, and the positioning pins 17 (see FIG. 4B) are inserted into the positioning holes 31f. By doing so, the connection position of the projecting body 12 of the distribution unit 2 with respect to the first divided body 31 can be positioned. The first divided body 31 is formed with two connecting holes 31g penetrating in the vertical direction.

<Second division body>
FIG. 6 shows the second divided body 32 of the antenna unit 3, where (a) is a plan view, (b) is a front view, and (c) is a bottom view.
As shown in FIGS. 2 and 6, the second divided body 32 is made of a disc formed thicker than the first divided body 31, and the lower surface thereof is disposed on the upper surface of the first divided body 31. . Further, the second divided body 32 has four second output waveguides 32a to 32d having a rectangular cross section composed of an inclined path portion formed so as to penetrate obliquely in the thickness direction (vertical direction). The cross-sectional shapes of the second output waveguides 32a to 32d are all the same size, and the same size as the cross-sectional shapes of the first output waveguides 31a to 31d of the first divided body 31. Has been.

  As shown in FIG. 6C, of the four second output waveguides 32 a to 32 d, the two second output waveguides 32 a and 32 c are connected to each other across the center line X <b> 2 of the second divided body 32. The other two second output waveguides 32b and 32d are formed symmetrically with respect to each other across the center line Y2 of the second divided body 32 orthogonal to the center line X2. The lower openings 32a2 and 32c2 of the second output waveguides 32a and 32c are formed symmetrically with respect to the center line Y2, and the lower openings 32b2 and 32d2 of the second output waveguides 32b and 32d are respectively center lines X2. It is formed symmetrically across the.

  On the other hand, as shown in FIG. 6A, the upper openings 32a1 and 32c1 of the second output waveguides 32a and 32c are formed asymmetrically with respect to the center line Y2, and the second output waveguides 32b and 32d The upper openings 32b1 and 32d1 are formed asymmetrically with respect to the center line X2. In the present embodiment, the upper openings 32a1 and 32c1 are formed so as to be biased toward the right side of the drawing with respect to the center line Y2, and the upper openings 32b1 and 32d1 are formed so as to be biased toward the upper side of the drawing with respect to the center line X2. ing. Therefore, two adjacent upper openings 32a1 and 32b1 are formed close to each other, and the other two adjacent upper openings 32c1 and 32d1 are formed apart from each other. As described above, the second output waveguides 32a to 32d of the second divided body 32 are formed so as to penetrate obliquely in the thickness direction (up and down direction), so that the upper openings 32a1 to 32d1 and the lower openings 32a2 are formed. It is formed so that the relative position with respect to 32d2 is different.

As shown in FIG. 6A and FIG. 6B, the peripheral edges of the upper openings 32 a 1 to 32 d 1 of the second output waveguides 32 a to 32 d are directed upward on the upper surface (ring-cut surface) of the second divided body 32. A protruding projection 32e having a circular shape in plan view is formed.
Two positioning holes 32g are formed through the outer peripheral portion of the second divided body 32 on the outer side in the radial direction from the connection convex portion 32e. By inserting the positioning pin 17 into each positioning hole 32g, the first The connection position of the 1st division body 31 with respect to the 2 division body 32 can be positioned. In addition, two connection holes 32 h penetrating in the vertical direction are formed in the outer peripheral portion of the second divided body 32.

<Third division>
FIG. 7 shows the third divided body 33 of the antenna unit 3, where (a) is a front view and (b) is a bottom view. FIG. 8 is an enlarged end view taken along the line CC of FIG.
As shown in FIGS. 7A and 7B, the third divided body 33 has a flange 34 and a single polyhedron 35. The flange 34 is formed in a disc shape and is integrally formed on the lower surface of the polyhedron 35.
The third divided body 33 includes four third output waveguides (guides) each having a rectangular cross section composed of second straight path portions formed so as to extend straight in the vertical direction (one direction) along an antenna surface 38 to be described later. Waveguide) 33a to 33d. The cross-sectional shapes of the third output waveguides 33a to 33d are all the same size, and the same size as the cross-sectional shapes of the second output waveguides 32a to 32d of the second divided body 32. Has been.

  As shown in FIG. 8, the third output waveguides 33a to 33d are adjacent to each other so as to be connected to the upper openings 32a1 to 32d1 of the second output waveguides 32a to 32d. , 33b are formed close to each other, and the other two adjacent third output waveguides 33c, 33d are formed apart from each other. Specifically, the third output waveguides 33a and 33c facing each other are formed to be offset to the right side in the drawing with respect to the center line Y3 of the polyhedron 35, and the third output waveguides 33b and 33d facing each other are The center line X3 of the polyhedron 35 perpendicular to the center line Y3 is formed so as to be biased upward in the drawing.

As shown in FIG. 7A, the connection convex part 32e of the second divided body 32 is fitted to the lower peripheral surface (ring-cut surface) of the flange part 34 at the opening peripheral edge part of the third output waveguides 33a and 33c. A connecting recess 34e having a circular shape in plan view is formed.
As shown in FIG. 7B, two bottomed circular positioning holes 34g are formed on the outer peripheral portion of the lower surface of the flange portion 34. As shown in FIG. By inserting the positioning pin 17 (see FIG. 4B) into each positioning hole 34g, the connection position of the third divided body 33 with respect to the second divided body 32 can be positioned.

  Further, two bottomed screw holes 34h are formed on the outer peripheral portion of the lower surface of the flange portion 34. Screws (not shown) that pass through the connection holes 31g of the first divided body 31 and the connection holes 32h of the second divided body 32 are screwed into the screw holes 34h from the connection holes 18 of the distributor 2. Thereby, the connection of the distribution part 2 and the antenna part 3 and the connection of the division bodies 31-33 of the antenna part 3 can be performed simultaneously.

  As shown in FIGS. 2 and 8, the polyhedron 35 has a main body portion 36 formed in a rectangular parallelepiped shape, and a flat lid portion 37 fixed to the upper surface of the main body portion 36. A plurality of (four) side surfaces of the main body 36 that are arranged in multiple planes (four-plane arrangement) are antenna surfaces 38, respectively. Each antenna surface 38 is formed with slots 38a to 38d communicating with the third output waveguides 33a to 33d and radiating horizontally polarized waves. As shown in FIG. 8, one slot 38 a to 38 d is formed on each antenna surface 38 in a horizontal cross section that is a cross section perpendicular to the plurality of antenna surfaces 38 of the polyhedron 35.

  The third output waveguides 33a to 33d are formed so as to open on the upper surface of the main body 36, respectively. These openings are covered with a lid portion 37. The lid portion 37 passes through the bolt 39 in the thickness direction and is fixed to the main body portion 36 by being screwed into a screw hole 36 a formed at the center of the upper surface of the main body portion 36. Thereby, the third output waveguides 33 a to 33 d are formed inside the polyhedron 35.

As shown in FIGS. 7A and 8, the slots 38 a to 38 d are formed by holes formed in the center portion in the width direction of each antenna surface 38, and are formed to extend in the vertical direction of the antenna surface 38. .
Further, the slots 38a to 38d are formed at the same height on the antenna surface 38. That is, as shown in FIG. 2, the third output is passed from the input waveguide 13 through the connection path 10, the distribution waveguide 14, the first output waveguides 31a to 31d, and the second output waveguides 32a to 32d. The four waveguide lengths from the slots 38a to 38d of the waveguides 33a to 33d are all set to the same length.

Further, as shown in FIG. 8, the slots 38a to 38d are formed with respect to the third output waveguides 33a to 33d at both sides in the longitudinal direction (both sides in the width direction) of the cross-sectional shape of the corresponding third output waveguides 33a to 33d. Of these, it is biased to either one.
Specifically, when the slots 38a to 38d are viewed from the outside of the antenna surfaces 38 in the directions of arrows a to d in FIG. 7, the positions where the slots 38a and 38d are formed are the positions of the third output waveguides 33a and 33d. It is biased to the right, and the positions where the slots 38b and 38c are formed are biased to the left of the third output waveguides 33b and 33c. Therefore, the slots 38a and 38b and the slots 38c and 38d that are adjacent to each other with the center line S of the input waveguide 13 of the distribution unit 2 are opposite to each other in the formation positions. The slots 38a and 38d and the slots 38b and 38c adjacent to each other without sandwiching the center line S are in the same direction in the formation position.

FIG. 9 is an explanatory diagram showing the relationship between the formation positions of the slots 38a to 38d and the phases in the respective branch directions E1 to E4.
As described above, when divided into a first system that distributes two to the two adjacent branch directions E1 and E2, and a second system that distributes two to the other two adjacent branch directions E3 and E4, In the system, two splits are performed with a phase difference of 0 ° / 180 ° from each other by the E-plane branch of the magic T. Therefore, when distributed by the distribution waveguide 14, as shown in FIG. E1 and E2 and the branching directions E3 and E4 are in reverse phase with each other, and two branching directions E1 and E4 and branching directions E2 and E3 adjacent to each other in different systems are H-plane branches of the magic T. Therefore, they are in phase with each other.

  However, the slots 38a and 38b in the branching directions E1 and E2 that are in opposite phases to each other and the slots 38c and 38d in the branching directions E3 and E4 are in opposite directions to each other, and Thus, since the waveguide length is the same, the direction of the radiated radio wave (direction of the electric field) is opposite to each other (180 ° difference). For this reason, the opposite phase (0 ° / 180 ° phase difference) due to branching and the direction of the radio wave are canceled, and radio waves having the same phase can be emitted. Thereby, the branch directions E1 and E2 and the branch directions E3 and E4 in the same system can be corrected in phase with each other.

In addition, the slots 38a and 38d in the branch directions E1 and E4 that are in phase with each other and the slots 38b and 38c in the branch directions E2 and E3 are in the same direction, and are as described above. Since the waveguide lengths are the same, the branching directions E1 and E4 and the branching directions E2 and E3 adjacent to each other in different systems are maintained in phase with each other.
Therefore, in the distribution unit 2, the power distributed in the opposite phase in the first and second systems can be corrected to the same phase by the antenna unit 3.

As shown in FIG. 2, the antenna unit 3 configured as described above is configured so that the power divided by the distribution unit 2 is distributed from the first output waveguides 31 a to 31 d of the first divided body 31 to the second divided body. Power is supplied from the lower ends of the third output waveguides 33a to 33d of the third divided body 33 to the upper ends via the 32 second output waveguides 32a to 32d, and the slots 38a to 38 of the third divided body 33 are supplied. Horizontally polarized light is radiated from 38d.
Further, the output waveguide formed in the antenna unit 3 is a first straight path unit (first output waveguides 31a to 31a) along the axial direction (vertical direction in the drawing) of the antenna unit 3 from the lower side of FIG. 31d), the slope portion (second output waveguides 32a to 32d), and the second straight passage portion (third output waveguides 33a to 33d) are arranged in this order. The antenna unit 3 is divided into a ring shape at the boundary between the first straight road part and the slope part and the boundary between the slope part and the second straight road part, so that the plurality of ( 3) divided bodies 31 to 33.

<Projection>
As shown in FIG. 8, the third divided body 33 has a plurality of (eight in the illustrated example) protrusions 6 a to 6 h that are integrally formed so as to protrude outward with respect to the polyhedron 35. These protrusions 6a to 6h are horizontal in the vicinity of the direction that bisects the angle formed by the front direction of the slot formed on one of the adjacent antenna surfaces 38 and the front direction of the slot formed on the other side. It functions as a sub-reflector for suppressing the emission of polarized waves. The protrusions 6a to 6h may be provided separately from the polyhedron 35.
Here, the “front direction” of a slot is a direction extending perpendicularly to the antenna surface from the center point of the slot toward the outside of the antenna surface on which the slot is formed. Further, “near the bisecting direction” means not only the direction that coincides with the bisecting direction but also the direction that is slightly deviated from the bisecting direction.

In the present embodiment, the front direction of the slot 38a is the upward direction in the figure along the center line Y3, and the front direction of the slot 38b is the right direction in the figure along the center line X3. The front direction of the slot 38c is the downward direction in the figure along the center line Y3, and the front direction of the slot 38d is the left direction in the figure along the center line X3.
Therefore, the angle formed by the front direction of the slot 38a formed on one of the adjacent antenna surfaces 38 formed with the slots 38a and 38d and the front direction of the slot 38d formed on the other is 90 degrees. The direction that bisects this angle is the direction of the arrow W1, which is a 45 degree direction.
Similarly, the bisecting direction between the adjacent antenna surfaces 38 formed with the slots 38a and 38b is the direction of the arrow W2, and the two antenna surfaces 38 formed with the slots 38b and the slots 38c are divided into the two directions. The direction of equally dividing is the direction of arrow W3, and the direction of equally dividing the adjacent antenna surfaces 38 formed with the slots 38c and 38d is the direction of arrow W4.

The protruding portions 6a and 6b are integrally formed so as to protrude outward (upper side in the drawing) with respect to the antenna surface 38 in which the slot 38a is formed.
The protruding portion 6a is formed in a triangular cross section, and an inclined surface 6a1 that gradually protrudes outward as it moves away from the slot 38a, and a vertical surface that is formed perpendicular to the antenna surface 38 on which the slot 38a is formed. 6a2. The distance D from the center line Y3 of the slot 38a to the inclined surface 6a1 of the protrusion 6a is set to 2.3 mm. Further, the protruding length H of the protruding portion 6a to the outside with respect to the antenna surface 38 is set to 0.8 mm.
The protruding portion 6b is formed symmetrically with the protruding portion 6a across the center line Y3 of the slot 38a, and an inclined surface 6b1 that gradually protrudes outward as the distance from the slot 38a increases, and the antenna surface on which the slot 38a is formed. And a vertical surface 6 b 2 formed perpendicularly to 38.

The protruding portions 6c and 6d are integrally formed so as to protrude outward (right side in the drawing) with respect to the antenna surface 38 in which the slot 38b is formed.
The protruding portion 6c is formed symmetrically with the protruding portion 6b across the center line S. The protruding portion 6c is inclined with respect to the inclined surface 6c1 that gradually protrudes outward as the distance from the slot 38b and the antenna surface 38 on which the slot 38b is formed. And a vertical surface 6c2 formed vertically.
The protruding portion 6d is formed symmetrically with the protruding portion 6c across the center line X3 of the slot 38b. The protruding portion 6d gradually protrudes outward along the antenna surface 38 from the slot 38b, and the slot 38b. And a vertical surface 6d2 formed perpendicular to the antenna surface 38 on which is formed.

The protruding portions 6e and 6f are integrally formed so as to protrude outward (lower side in the figure) with respect to the antenna surface 38 in which the slot 38c is formed.
The protruding portion 6e is formed symmetrically with the protruding portion 6b across the center line X3, with respect to the inclined surface 6e1 that gradually protrudes outward as the distance from the slot 38c increases, and the antenna surface 38 in which the slot 38c is formed. And a vertical surface 6e2 formed vertically.
The protruding portion 6f is formed symmetrically with the protruding portion 6e across the center line Y3 of the slot 38c, and an inclined surface 6f1 that gradually protrudes outward as the distance from the slot 38c increases, and the antenna surface on which the slot 38c is formed. And a vertical surface 6f2 formed perpendicularly to 38.

The protruding portions 6g and 6h are integrally formed so as to protrude outward (left side in the drawing) with respect to the antenna surface 38 in which the slot 38d is formed.
The protruding portion 6g is formed symmetrically with the protruding portion 6f across the center line S. The protruding portion 6g is inclined with respect to the inclined surface 6g1 that gradually protrudes outward as the distance from the slot 38d and the antenna surface 38 in which the slot 38d is formed. And a vertical surface 6g2 formed vertically.
The projecting portion 6h is formed symmetrically with the projecting portion 6g across the center line X3 of the slot 38d, and an inclined surface 6h1 that gradually projects outward as the distance from the slot 38d increases, and the antenna surface on which the slot 38d is formed. And a vertical surface 6 h 2 formed perpendicularly to 38.
As shown to Fig.7 (a), the protrusion parts 6a-6h are formed over the longitudinal direction full length (up-down direction in a figure) of each antenna surface 38. As shown in FIG.

With the above configuration, among the adjacent antenna surfaces 38 each having the slot 38a and the slot 38d, the horizontally polarized wave radiated from the slot 38a formed on one side and the slot 38d formed on the other side are radiated. The horizontal polarization is suppressed from being emitted in the vicinity of the arrow W1 direction by the protrusion 6a and the protrusion 6h.
In addition, among the adjacent antenna surfaces 38 in which the slots 38a and 38b are respectively formed, the horizontal polarization radiated from the slot 38a formed on one side and the horizontal polarization radiated from the slot 38b formed on the other side. Waves are suppressed from being emitted in the vicinity of the arrow W2 direction by the protrusions 6b and 6c, respectively.

In addition, among the adjacent antenna surfaces 38 in which the slots 38b and 38c are respectively formed, the horizontal polarization radiated from the slot 38b formed on one side and the horizontal polarization radiated from the slot 38c formed on the other side. The wave is suppressed from being emitted in the vicinity of the arrow W3 direction by the protrusion 6d and the protrusion 6e.
Further, among the adjacent antenna surfaces 38 each formed with the slot 38c and the slot 38d, horizontal polarization radiated from the slot 38c formed on one side and horizontal polarization radiated from the slot 38d formed on the other side. The wave is suppressed from being emitted in the vicinity of the arrow W4 direction by the protrusion 6f and the protrusion 6g.

FIG. 10 is a diagram illustrating the horizontal plane directivity of a conventional omnidirectional antenna. Moreover, FIG. 11 is a figure which shows the horizontal surface directivity of the omnidirectional antenna 1 of this embodiment.
As shown in FIG. 10, in the conventional horizontal plane directivity, the vicinity of the W1 direction (−60 degrees to −60 degrees to the 0 degrees direction, 90 degrees direction, −180 degrees direction, and −90 degrees direction) of each slot. Horizontally polarized radiation in the vicinity of −30 degrees), in the vicinity of the W2 direction (around 30 degrees to 60 degrees), in the vicinity of the W3 direction (around 120 degrees to 150 degrees), and in the vicinity of the W4 direction (around −150 degrees to −120 degrees). Is getting stronger. For this reason, the conventional omnidirectional deviation (difference between the maximum gain and the minimum gain) is as large as 5.3 dB.

  In contrast, as shown in FIG. 11, in the horizontal plane directivity of the present embodiment, the radiation of the horizontally polarized waves in the front direction of each slot is stronger than that in the prior art, and the horizontally polarized waves in the vicinity of the W1 to W4 directions. Radiation is weaker than before. Thereby, the omnidirectional deviation of the present embodiment is 3.6 dB, which is smaller than the conventional omnidirectional deviation. That is, it can be seen that the omnidirectional deviation of the horizontal plane directivity can be suppressed by providing the projecting portions 6a to 6h on each antenna surface 38 as in the present embodiment.

<Modified example of protrusion>
In addition, although the protrusion parts 6a-6h of this embodiment are formed in the cross-sectional triangle shape, you may be formed in the cross-sectional rectangular shape like the modification shown in FIG. Moreover, although the protrusion parts 6a-6h of this embodiment are each provided in each antenna surface 38 separately, like the modification shown in FIG. 13, protrusion part 6a, 6h adjacent to each other, and protrusion part 6b. , 6c, the protrusions 6d and 6e, and the protrusions 6f and 6g may be integrally formed on each antenna surface 38.

Moreover, although the eight protrusion parts of this embodiment are formed, as shown in FIG. 14, four protrusion parts 6A-6D of cross-sectional rectangular shape are formed in the corner | angular part of adjacent antenna surfaces 38, for example. It may be provided as a separate body. In this case, the protrusion 6A also functions as the protrusion 6a and the protrusion 6h in FIG. 8, and the protrusion 6B also functions as the protrusion 6b and the protrusion 6c in FIG. In addition, the protruding portion 6C also functions as the protruding portion 6d and the protruding portion 6e in FIG. 8, and the protruding portion 6D also functions as the protruding portion 6f and the protruding portion 6g.
Further, in the modification shown in FIG. 14, the four projecting portions 6 </ b> A to 6 </ b> D are provided separately from the polyhedron 35, but as in the modification shown in FIG. The protrusions 6A to 6D, which are integrally formed so as to taper the pair of concave arc surfaces, may be formed integrally with the part.

<Slot formation position with respect to waveguide>
As shown in FIG. 2, from the upper end of the third output waveguides 33 a to 33 d (the lower surface of the lid portion 37) formed inside the polyhedron 35 to the center point of the slots 38 a to 38 d formed on each antenna surface 38. Is set to satisfy the following formula (1): L = (λ _g / 4) + n × (λ _g / 2) (1)
Here, λ _g is the wavelength in the waveguide of the design center frequency in the frequency band. n is an integer of 1 or more.
The n is preferably an even number, and more preferably n = 2. In this embodiment, n = 2 and the distance L is set to 5λ _g / 4.

FIG. 16 is a diagram showing the horizontal plane directivity when the distance L is λ _g / 4 which is the same distance as the conventional one (hereinafter simply referred to as “conventional distance”) in the omnidirectional antenna 1 of the present embodiment. . FIG. 17 is a diagram illustrating the horizontal plane directivity of the omnidirectional antenna 1 (L = 5λ _g / 4) of the present embodiment.
As shown in FIG. 16, in the horizontal plane directivity in the case of the conventional distance, the cross polarization discrimination degree which is a level difference between the main polarization and the cross polarization is 11.7 dB. On the other hand, as shown in FIG. 17, in the horizontal plane directivity of this embodiment, the main polarization is almost the same as the main polarization at the conventional distance, but the cross polarization is more than the cross polarization at the conventional distance. Is also getting weaker. Thereby, the cross polarization discrimination degree of this embodiment is 22.1 dB, which is larger than the cross polarization discrimination degree of the conventional distance. That is, by setting the distance L to 5λ _g / 4 (n = 2) as in this embodiment, the horizontal plane directivity cross-polarization discrimination can be improved and the influence of cross-polarization can be reduced. I understand.

FIG. 18 is a diagram showing the horizontal plane directivity when the distance L is 3λ _g / 4 (n = 1) in the omnidirectional antenna 1 of the present embodiment. FIG. 19 is a diagram showing horizontal plane directivity when the distance L is 7λ _g / 4 (n = 3) in the omnidirectional antenna 1 of the present embodiment.
As shown in FIGS. 18 and 19, in each horizontal plane directivity when the distance L is 3λ _g / 4 and 7λ _g / 4, the cross-polarization discrimination is 20.0 dB and 22.0 dB, which is the conventional distance. The cross-polarization discrimination is improved over the horizontal plane directivity. That is, in the omnidirectional antenna 1 of the present embodiment, it can be seen that even when n is 1 and 3, the influence of cross polarization on the horizontal plane directivity can be reduced.
Also, cross-polarization discrimination in the case where the distance L and 3 [lambda] _g / 4 and 7λ _g / 4, the distance L of 5 [lambda] _g / 4 and the cross polarization discrimination of omnidirectional antenna 1 of this embodiment The value is smaller than the degree. Therefore, it can be seen that when the distance L is set to 5λ _g / 4 (n = 2), the cross polarization discrimination in the horizontal plane directivity can be most effectively improved.

FIG. 20 shows an omnidirectional antenna 1 according to this embodiment in which the distance L is 5λ _g / 4 (n = 2) and an omnidirectional antenna 1 in which the distance L is 13λ _g / 4 (n = 6). It is a figure which shows VSWR of.
As shown in FIG. 20, when the distance L is 13λ _g / 4, in the center frequency band (41.46 to 41.90 GHz), the VSWR shows a good value of 1.25 or less. In other frequency bands, the VSWR is a value exceeding 1.25, and the frequency band showing a good VSWR is narrow. On the other hand, when the distance L is 5λ _g / 4, the VSWR shows a good value of 1.25 or less over a wide frequency band (41.00 GHz to 42.00 GHz). . That is, it can be seen that by setting the distance L to 5λ _g / 4 (n = 2), the influence of cross polarization on directivity can be reduced without narrowing the usable frequency band.

<Operational effects of this embodiment>
As described above, according to the omnidirectional antenna 1 according to the present embodiment, the adjacent antenna surfaces 38 are provided by the protruding portions 6 a to 6 h provided to protrude outwardly from the respective antenna surfaces 38 of the polyhedron 35 of the antenna portion 3. It is possible to suppress the horizontal polarization from being radiated from the slots formed respectively in the vicinity of the direction that bisects the angle formed by the front directions of these two slots. Thereby, compared with the conventional omnidirectional antenna, an omnidirectional deviation can be suppressed and antenna performance can be improved.

  In particular, in the case of the omnidirectional antenna 1 which is miniaturized by forming one slot 38a to 38d on each antenna surface 38 as in this embodiment, the horizontal polarization radiated from each slot 38a to 38d is reduced. Since the beam width becomes wide, horizontal polarization is strongly radiated in the vicinity of the direction that bisects the angle formed by the front directions of the slots 38a to 38d formed in the adjacent antenna surfaces 38, and the omnidirectional deviation is further increased. There is a problem of growing. Therefore, when the slots 38a to 38d are formed on each antenna surface 38 one by one, the omnidirectional deviation that is particularly problematic can be effectively suppressed by the protrusions 6a to 6h.

  Further, as a general technique for suppressing the omnidirectional deviation, it is conceivable to shorten the width of each antenna surface 38. This technique is a small size in which a plurality of waveguides 33a to 33d are formed inside the polyhedron 35. When applied to the omnidirectional antenna 1, the polyhedron 35 becomes too small as a whole, and the waveguides 33a to 33d cannot be formed inside. On the other hand, in this embodiment, since the protrusions 6a to 6h that suppress the omnidirectional deviation are provided to protrude outward from the polyhedron 35, the waveguides 33a to 33d are provided inside the polyhedron 35. An omnidirectional deviation can be suppressed while securing a space to be formed. Therefore, the structure in which the protrusions 6a to 6h are provided on the polyhedron 35 to suppress the omnidirectional deviation is applied to a small omnidirectional antenna in which a plurality of waveguides 33a to 33d are formed inside the polyhedron 35. It is even more effective in some cases.

Also, in the case of an omnidirectional antenna that radiates horizontally polarized waves, the structure for making it omnidirectional is more complex than in the case of an omnidirectional antenna that radiates vertically polarized waves. It is necessary to make it. Even when the frequency band is 10 GHz or more, it is necessary to make the antenna structure as small as possible in order to reduce transmission loss.
However, as described above, when the small omnidirectional antenna 1 in which the plurality of waveguides 33a to 33d are formed inside the polyhedron 35 is applied, the general omnidirectional deviation is suppressed as described above. When using this technique, the polyhedron 35 becomes too small as a whole, and the waveguides 33a to 33d cannot be formed inside. On the other hand, in this embodiment, since the protrusions 6a to 6h that suppress the omnidirectional deviation are provided to protrude outward from the polyhedron 35, the waveguides 33a to 33d are provided inside the polyhedron 35. An omnidirectional deviation can be suppressed while securing a space to be formed. Therefore, the structure which suppresses the omnidirectional deviation by projecting the protrusions 6a to 6h on the polyhedron 35 is respectively applied to the omnidirectional antenna that radiates horizontal polarization and the omnidirectional antenna whose frequency band is 10 GHz or more. It becomes more effective when applied.

In addition, since the distance L from the upper ends of the waveguides 33a to 33d to the center point of the slots 38a to 38d is set to satisfy the above formula (1) inside the polyhedron 35, the conventional omnidirectional antenna As compared with the above, it is possible to reduce the influence of cross polarization in the horizontal plane directivity, and to improve the antenna performance.
In addition, since n is an even number, the influence of cross polarization on the horizontal plane directivity can be reduced without changing the formation positions of the slots 38a to 38d.
Furthermore, since n is 2, the influence of cross polarization in the horizontal plane directivity can be further effectively reduced without narrowing the usable frequency band.

Second Embodiment
FIG. 21 is a cross-sectional view showing the omnidirectional antenna 1 according to the second embodiment of the present invention.
As shown in FIG. 21, the omnidirectional antenna 1 of the present embodiment is different from the first embodiment in that the configuration of the third divided body 33 of the antenna unit 3 is mainly different. In the third divided body 33 of the present embodiment, the polyhedron 35 is formed longer in the vertical direction than the third divided body 33 of the first embodiment, and the cylindrical portion 43 of the radome 4 also corresponds to this. It is long in the direction. In each antenna surface 38, a plurality of slots 38a to 38d are formed in a straight line at predetermined intervals in the vertical direction. The distance P1 between the center points of the vertically adjacent slots is set in the vicinity of one wavelength λ _g in the waveguide wavelength.
The distance L from the upper end of the third output waveguides 33a to 33d formed inside the polyhedron 35 to the center point of the slot closest to the upper end among the plurality of slots 38a to 38d formed on each antenna surface 38 is , It is set to satisfy the equation (1) shown in the first embodiment. The points that are not described in the second embodiment are the same as in the first embodiment.

In the present embodiment, the plurality of slots formed on each antenna surface 38 are linearly formed in the vertical direction, but are formed in a staggered pattern in the vertical direction as in the modification shown in FIG. May be. In this case, the second output waveguides 32a to 32d of the second divided body 32 are formed so as to extend straight in the thickness direction (vertical direction), and the third output waveguides 33a to 33d of the third divided body 33 are The second output waveguides 32a to 32d are formed at positions where they are connected in communication with the upper openings. Further, the distance P2 between the center points of vertically adjacent slots is set in the vicinity of a half wavelength (λ _g / 2) as the wavelength in the waveguide. For this reason, the omnidirectional antenna 1 shown in FIG. 22 can make the length of the whole antenna vertical direction compact compared with the omnidirectional antenna 1 shown in FIG.

<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.

DESCRIPTION OF SYMBOLS 1 Nondirectional antenna 2 Distribution part 3 Antenna part 4 Radome 5 Adjustment element 6a-6h Protrusion part 6a1-6h1 Inclined surface 6a2-6h2 Vertical surface 6A-6D Protrusion part 10 Connection path 11 Base body 12 Protrusion body 13 Input waveguide 14 Distribution Waveguide 14a 1st recessed part 14b 2nd recessed part 14c 3rd recessed part 14d 4th recessed part 14e Central recessed part 15 Positioning pin 16 Positioning pin 17 Positioning pin 18 Connection hole 19 Connection hole 31 1st division bodies 31a-31d 1st output waveguide 31e Lower surface 31f Positioning hole 31g Connection hole 32 Second divided bodies 32a to 32d Second output waveguides 32a1 to 32d1 Lower opening 32a2 to 32d2 Upper opening 32e Connection protrusion 32g Positioning hole 32h Connection hole 33 Third divided bodies 33a to 33d Third Output waveguide 34 flange 34e connection recess 34g positioning hole 34h screw hole 35 Face body 36 Main body portion 36a Screw hole 37 Cover portion 38 Antenna surface 38a to 38d Slot 39 Bolt 41 Radome main body 42 Fixing plate 43 Cylindrical portion 44 Ring portion 45 Nut portion D Distance H Length L Distance P1 Distance P2 Distance S Center Line X1 Center line Y1 Center line X2 Center line Y2 Center line X3 Center line Y3 Center line Z Road axis

Claims (11)

An omnidirectional antenna having a plurality of antenna surfaces arranged in multiple planes, and including an antenna portion formed with slots for radiating polarized waves in a predetermined frequency band on each antenna surface,
Polarization is radiated in the vicinity of a direction that bisects the angle formed by the front direction of the slot formed on one of the adjacent antenna surfaces and the front direction of the slot formed on the other side. In order to suppress this, an omnidirectional antenna including a protruding portion that protrudes outward with respect to the antenna portion.   The omnidirectional antenna according to claim 1, wherein the protruding portion is provided to protrude outward with respect to at least one of the adjacent antenna surfaces.   3. The omnidirectional antenna according to claim 1, wherein one slot is formed on each antenna surface in a cross section perpendicular to the plurality of antenna surfaces of the antenna unit. 4. The antenna unit includes a single polyhedron having a plurality of antenna surfaces and a plurality of waveguides formed therein so as to communicate with the slots of the antenna surfaces, respectively.
The omnidirectional antenna according to any one of claims 1 to 3, wherein the protruding portion is provided to protrude outward with respect to the polyhedron.   The omnidirectional antenna according to claim 4, wherein the number of antenna surfaces is four.   The omnidirectional antenna according to claim 4 or 5, wherein the polarization is horizontal polarization.   The omnidirectional antenna according to any one of claims 4 to 6, wherein the frequency band is 10 GHz or more. The antenna unit includes a single polyhedron having the plurality of antenna surfaces and a plurality of waveguides respectively communicating with the slots of the antenna surfaces,
The waveguide is formed to extend in one direction along the antenna surface inside the polyhedron, and is fed from one end side in the one direction,
The distance L from the other end in the one direction of the waveguide to the center point of the slot closest to the other end is set so as to satisfy the following expression. The omnidirectional antenna according to item 1.
L = (λ _g / 4) + n × (λ _g / 2)
Here, λ _g is the wavelength in the waveguide of the design center frequency in the frequency band, and n is an integer of 1 or more.   The omnidirectional antenna according to claim 8, wherein n is an even number.   The omnidirectional antenna according to claim 9, wherein n is two. A polyhedron having a plurality of antenna surfaces arranged in multiple planes, a slot that is formed on each antenna surface and radiates polarized waves in a predetermined frequency band, and a plurality of waveguides that respectively communicate with the slots on each antenna surface An omnidirectional antenna comprising:
The waveguide is formed to extend in one direction along the antenna surface inside the polyhedron, and is fed from one end side in the one direction,
A distance L from the other end of the waveguide in the one direction to the center point of the slot closest to the other end is set to satisfy the following expression.
L = (λ _g / 4) + n × (λ _g / 2)
Here, λ _g is the wavelength in the waveguide of the design center frequency in the frequency band, and n is an integer of 1 or more.

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