JP3018353B2 - Radial line slot antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a radial line slot antenna using a radial waveguide used in SHF and EHF bands.

[Conventional technology]

As a prior art, for example, there is one disclosed in Japanese Patent Publication No. 64-1965. That is, the wavelength of the propagation mode, which is the most fundamental propagation mode in the radial waveguide composed of the upper and lower disc-shaped conductors disposed at equal intervals and spreads uniformly from the center in the radial direction with the same strength, is λ _g The first conductor at a distance of δ from the center on the radial axis of the upper conductor.
Point, on an axis perpendicular to this axis, from the center δ + 1/4 × λ _g
A third point at a distance of δ + 1/2 × λ _g coaxial with the second point and the first point and opposite to the first point from the center and coaxial with the second point. A fourth point at a distance of δ + 3/4 × λ _{g on} the opposite side of the second point from the center, and a fifth point at a distance of δ + λ _g from the center in the same direction and in the same direction as the first point. points, and the spiral lines sequentially through a group of points defined by the same manner, the radiating element comprises a set of slots disposed at the center distance of each other in 1/4 × λ _g in the orthogonal line, A circularly polarized planar array antenna characterized in that one of the slots is sequentially arranged in a substantially C-shape having an inclination of about 45 ° with respect to the radial direction.

[Problems to be solved by the invention]

However, the conventional antenna described above, because the spacing between the spiral adjacent to each other is lambda _g, the influence of grating lobes is relatively large, there is a problem that it is impossible to obtain a sufficient gain. Further, although also made possible to suppress the grating lobes of lambda _g was shorter than the spatial wavelength lambda _0, since lambda _g is close to the value of lambda _0, it can not be suppressed grating lobes enough, sufficient gain I can't get it.

In general, it is known that the shorter the slot interval, the smaller the effect of the grating lobe. Therefore, it is conceivable to suppress the grating lobe by arranging the slots densely. In this case, the problem of how to radiate radio waves vertically from the radial waveguide and make it circularly polarized must be solved.

 The present invention has the above object as its object.

It is another object of the present invention to provide a circularly polarized radial line slot antenna in which the influence of the grating lobe is small and a sufficient gain is obtained.

[Means for solving the problem]

The present invention has been made to solve the above problems,
A slot plate having a plurality of slots, the radial line slot antenna by forming a radial waveguide includes a conductive opposed to the slot plate, when the wavelength in the radial waveguide and lambda _g, radial axis of the slot plate Above, a first point at a distance of δ from its center, δ + λ _g
A second point at a distance of δ, a third point at a distance of δ + 2 × λ _g
, A main slot arranged on a first spiral consisting of Archimedes' spirals passing through a group of points obtained in the same manner, and a center on the same side as the first point on the same axis as the first point. The first point at a distance of δ + 1/3 × λ _{g from} ,
A second point at a distance of (δ + 1/3 × λ _g ) + λ _g ,
A first sub-slot arranged on a third point at a distance of (δ + 1/3 × λ _g ) + 2 × λ _g, an Archimedean spiral passing through a point group obtained in the same manner,
And the point of the first "at a distance of the first point and coaxially with the first center thereof from δ + 2/3 × on the same side as the point of lambda _g,
A second ″ point at a distance of (δ + 2/3 × λ _g ) + λ _g ,
A third sub-slot arranged on a third spiral consisting of an Archimedean spiral passing through a third point at a distance of (δ + 2/3 × λ _g ) + 2 × λ _g , and a point group obtained in the same manner. A radial line slot antenna, wherein the main slot, the first sub-slot, and the second sub-slot are arranged in a positional relationship rotated by 120 degrees from each other.

[Action]

The radial line slot antenna of the present invention has
Three spirals of 1/3 × λ _g , ie, the first spiral, the second spiral
The main slot, the first on the spiral and the third on the spiral, respectively
Since the sub-slot and the second sub-slot are formed, the arrangement of the slots is dense, the grating rope is suppressed, and the main slot, the first sub-slot, and the second sub-slot have a positional relationship rotated by 120 degrees with respect to each other. Since the radio waves are radiated, the radiated radio waves become circularly polarized waves in the same phase, and the above-mentioned problem is solved. [Example] The present invention will be described in detail using examples.

FIG. 1 is an explanatory view of a radial line slot antenna according to the present invention. In FIG. 1, (1) is a slot plate, and the slot plate (1) is a metal disk, which is formed by etching or the like. Slot (2).
Further, (3) is a frame, and the frame (3) is obtained by drawing a peripheral edge of a metal disk, and the slot plate (1) is joined to the peripheral edge, sealed with an epoxy resin or the like, and a radial is inserted therein. A waveguide (4) is formed. At the approximate center of the slot plate (1), a coaxial (5) is attached.

A partition plate (not shown) is disposed in an internal space formed by the slot plate (1) and the frame (3), and the radial waveguide (4) is divided into an upper waveguide and a lower waveguide.
A folded portion of the waveguide may be formed on the outer periphery of the partition plate.

A radome (6) is mounted on the slot plate (1) to prevent intrusion of rain or the like. The radome (6) is formed of a Teflon material or the like which is easy to slip so that snow or the like does not accumulate, and its periphery is sealed by overlapping with the slot plate (1) and the frame (3). Further, a spacer (7) made of styrene foam or the like may be laminated between the radome (6) and the slot plate (1) as necessary.

Next, an arrangement pattern of the slots (2) provided in the slot plate (1) will be described.

As shown in FIG. 2, the slot (2) is formed on three spirals, that is, the main slot (2a) on the first spiral (11), and the first sub-slot (2) on the second spiral (12). 2b),
A second sub-slot (2c) is formed on the third screw (13). The first screw (11) is a first point located at a distance of δ from the center O of the slot plate (1), where λ _g is the wavelength of the axisymmetric propagation mode in the radial waveguide (4). second point at a distance of _{δ + λ g, δ + 2} × λ
third point on the _g distances, point group obtained in the same manner, that is, the Archimedean spiral which passes through the point group given at intervals of lambda _g from the first point. That is, the polar coordinates (R, θ) of the midpoint of the main slot (2a) are given by the equation R =
δ + λ _g × θ / 2π so that the main slot (2
a) are arranged sequentially.

On the other hand, the second spiral line (12) is coaxial with the first point and is δ + 1/3 × λ _g from the center thereof on the same side as the first point.
1 ′ point at a distance of (δ + 1/3 × λ _g ) + λ _g , a second ′ point at a distance of (δ + 1/3 × λ _g ) + 2 × λ _g
Third 'point, point group obtained in the same manner, i.e. first' in the Distance consisting Archimedean spiral which passes through the lambda _g point group given by the intervals in terms of. That is, the polar coordinates (R, θ) of the midpoint of the first subslot (2b) are given by the equation
The first sub-slots (2b) are sequentially arranged so as to satisfy R = (δ + 1/3 × λ _g ) + λ _g × θ / 2π.

It said third spiral (13), the point of the first "at a distance of the first point and coaxially the first point and the center of δ + 2/3 × λ _g on the same side, ([delta] + 2 / A second ″ point at a distance of 3 × λ _g ) + λ _g , a third ″ point at a distance of (δ + 2/3 × λ _g ) + 2 × λ _g , and a similar point group, consisting Archimedean spiral which passes through the lambda _g point group given by the intervals in terms of 1 ". That is, the polar coordinates (R, θ) of the midpoint of the second sub-slot (2c) are given by the equation R = (δ
+ 2/3 × λ _g ) + λ _g × θ / 2π The second sub-slots (2c) are sequentially arranged to satisfy the condition.

These slots are formed in the same direction in each of the first spiral (11), the second spiral (12), and the third spiral (13), and are formed in the first spiral (11). The main slot (2a) formed, the first sub-slot (2b) formed in the second screw (12), and the second sub-slot (2c) formed in the third screw (13) are the second As shown in FIG. 6B, the two parts are formed in a positional relationship rotated by 120 degrees from each other.

Thus, by arranging the main slot (2a), the first sub-slot (2b), and the second sub-slot (2c) in a positional relationship rotated by 120 degrees, as shown in FIG. 2 (C). , The phases can be matched, that is, they can be in phase.

〔The invention's effect〕

The radial line slot antenna according to the present invention can obtain a circularly polarized radial line slot antenna having a small influence of the grating lobe and a high gain performance.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an explanatory view in which a part thereof is cut away, FIG. 2 (a) is an explanatory view of a slot pattern, and FIG. 2 (b) shows a positional relationship of the slots. FIG. 2 (c) is an explanatory view showing the in-phase condition. (1) Slot plate (2) Slot (3) Frame (4) Radial waveguide (5) Coaxial (6) Radome (7) Spacer (11) 1st spiral (12) ... 2nd spiral (13) ... 3rd spiral

Claims (1)

(57) [Claims] A slot plate having a 1. A number of slots, the radial line slot antenna by forming a radial waveguide includes a conductive opposed to the slot plate, when the wavelength in the radial waveguide and lambda _g, slot on the radial axis of the plate, the first point in the distance [delta] from the center, a second point at a distance of [delta] + lambda _g, third point at a distance of δ + 2 × λ _g, in the same manner to give A main slot arranged on a first spiral consisting of an Archimedean spiral passing through a set of points, and coaxial with the first point, on the same side as the first point, δ + 1/3 × λ _g from its center. the first 'point, (δ + 1/3 × λ g) + λ g second at a distance of' in the distance of a point, the third 'point in the distance (δ + 1/3 × λ g) + 2 × λ g , On a second spiral consisting of an Archimedean spiral passing through a point cloud obtained in the same manner. The first sub-slot and location, and the first "at a distance of the first point and coaxially with the first center thereof from δ + 2/3 × on the same side as the point of lambda _g
Point, (δ + 2/3 × λ g) second at a distance of + lambda _g "point, (δ + 1/3 × λ g) + 2 × 3 at a distance of lambda _g"
, A second sub-slot arranged on a third spiral consisting of an Archimedes spiral passing through a point group obtained in the same manner, and the main slot, the first sub-slot, the second sub-slot and A radial line slot antenna, wherein the antennas are arranged in a positional relationship rotated by 120 degrees.