JPS62171301A - Slot array antenna system - Google Patents

Abstract

PURPOSE:To improve the vertical directivity of a slot array antenna system and to reduce its size by providing a dielectric which has a forward projection part at the aperture end of a horn and employing an inside/outside double structure for the dielectric. CONSTITUTION:A slot waveguide 1 is fitted to the base part 2 of the horn 2. The horn 2 direct a radio wave radiated from the slot waveguide 1 in one direction. The dielectric 3 further converges the radio wave which is directed by the horn 2 and is fitted to the aperture end of the horn 2 in a shield state. This dielectric 3 has an circular arc part 3a curved about the slot waveguide 1 at the aperture end position of the horn and the projection part 3b projecting forward from the upper and lower center positions of the circular arc part 3a, and is formed in the inside/outside double structure on the whole while consisting of an inside dielectric 3i and an outside dielectric 3o almost in the same shape. The inside dielectric 3i and outside dielectric 3o overlap each other at their upper and lower edges and have a constant gap 5 at other respective parts.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a slot array antenna device mainly used as a radar antenna.

<Prior Art> Conventionally, as a slot array antenna device for radar, a slot waveguide 23 is generally used, as shown in FIG. 2, in which a slot waveguide 22 is provided at the base of a metal horn 21.

In addition, a slot array antenna device 31.41 in which a dielectric material is provided at the end of a slot waveguide has already been proposed (Japanese Unexamined Patent Publication No. 31205/1983).

<Problems to be Solved by the Invention> By the way, in the slot array antenna device 23 shown in FIG. 2, the aperture size B of the horn 21.

The vertical directivity can be sharpened by increasing the . However, if the aperture size B is greatly shifted, not only the aperture size B2 but also the v of the horn 21 will inevitably change.
Since the projecting dimension in the direction of rotation becomes long, the whole becomes large, and when used as a radar antenna, a large and powerful motor is required to drive the rotation, which is uneconomical.

In addition, in such a slot array antenna device 23, by widening the aperture angle of the pawn 21, the aperture size B can be enlarged and the directivity can be sharply shifted. 21 opening size B
Since the protruding dimensions 1 and 2 are shorter than those of the pawn 21, the wave front surface of the radio waves emitted from the pawn 21 is not parallel to the aperture surface, resulting in a disadvantage that the antenna efficiency is reduced.

As described above, it is difficult to miniaturize the slot array antenna device 23 of the type shown in FIG. 2 without reducing the directivity or antenna efficiency.

On the other hand, without expanding the horn opening size,
Slot array antenna devices 31 and 41 shown in FIGS. 3 and 4 were proposed in order to obtain sufficient directivity.

The device 31 shown in FIG. 3 has a slot waveguide 33 attached to the base of a rectangular metal frame 32 whose front surface is σt1 apart, and a forward protrusion at the open end of the frame 32. A dielectric material 34 having a dielectric material 34 is attached thereto.

In addition, in the one shown in FIG. 4, a slot waveguide 43 is provided at the base of a metal pawn 42, and a pair of plate-shaped dielectrics 4 are provided on the inner surface of the horn 42 and project parallel to each other forward.
4.44 was installed.

In each of the slot array antenna devices 31, 41 described above, the dielectric 34, 44 acts to form a main lobe, so the directivity becomes sharp, and therefore it is necessary to significantly enlarge the open dimensions of the pawns, etc. It disappears.

However, in such a slot array antenna device 31.41, the opening size of the horn etc. is suppressed to a short size, but instead, the forward protrusion size L3. L4 becomes quite long and this dielectric 34
, j4 protrusions not only increase the overall space occupied but also increase weight. Another problem is that a strong attachment means is required to fix the dielectric members 34, 44 that protrude long forward to a horn or the like.

The present invention has been made in view of the above-mentioned problems, and uses a dielectric material without protruding the dielectric material forward for a long time, sharpens the directivity, and miniaturizes the entire antenna. The object of the present invention is to reduce the weight and simplify and downsize the turning drive means when used as a radar antenna.

Means for Solving the Problems> In order to achieve the above object, the present invention has a dielectric material attached to the open end of a horn having a slot waveguide at its base in a shielding manner. A slot array antenna device (1) was constructed by forming a protruding portion protruding forward at the vertical center position, and using the dielectric material as an inner and outer double structure with a filling layer sandwiched between them, which is similar to an air layer.

<Actual Example> The present invention will be described in detail below with reference to the embodiment shown in the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

The slot array antenna device of this embodiment has a wave JtX
As [J-shito waveguide 1 and metal 2I-suno horn 2]
(Glass side 141: Reinforced plastic) 1 dielectric material 3.

The slot waveguide 1 is a rectangular waveguide with a slot 4 formed as a radiating element on the short side surface.

This slot waveguide 1 is connected to the 1. (The Bohr 2 acts to direct the radio waves emitted from the slot waveguide 1 in one direction.

The dielectric 3 serves to further converge the radio waves directed by the pawn 2, and is attached to the open end of the pawn 2 in a shielding manner.

This dielectric 3 has a circular arc portion 3a that curves around the slot waveguide 1 at the open end position of the Σ1;
It has a shape having a protruding portion 3b protruding forward from the vertical center position of a, and has an inner/outer double structure as a whole, and is composed of an inner dielectric 31 and an outer dielectric 30 that are substantially the same shape as each other. The inner dielectric 3I and the outer dielectric 30 are overlapped with each other at the upper and lower edges, and are otherwise spaced apart from each other by a constant distance 5 Cf. That is, an air layer exists between the inner and outer cylindrical dielectrics 3i and +30. Note that the space 5 between the inner and outer thermoelectric bodies 3i and 3o may be filled with foamed urethane. In the figure, reference numeral 6 is a grating for orthogonal polarization suppression.

According to the above t1 configuration, the protrusion dimension of the dielectric 3 is the extra ζ)
Sufficient vertical directivity can be obtained without any extension. The present invention proposes a slot array antenna device (■) having the same structure as the illustrated embodiment, a slot array antenna device (■) with a temporary structure made of a single dielectric material, and a (L) The vertical directivity was measured in comparison with the structure shown in Figure 2) (2), and the following results were obtained. In that case, in the three types of slot array antenna devices to be measured, the common sliding portions have structures of the same shape and size. The opening dimension of the horn is 180 mm vertically, and the protrusion dimension of the dielectric is 2
It was set to 10 mm. The frequency of radiated radio waves is 3050MIrz
The angle range where the electric field strength exceeds the 3 dB level was measured.

■Pone only (no dielectric) 37゜■Single dielectric structure 29゜■Example
24° (air is present between the inner and outer cylindrical dielectrics 3i and 3o). From this measurement result, a dielectric 3 having a forward protrusion 3b is provided at the open end of the horn 2, and the dielectric 3 is connected to the inner and outer cylindrical dielectrics 3i and 3o. It can be seen that vertical directivity is improved by creating a layered structure.

In general, vertical directivity is improved by providing a dielectric body with a forward protrusion at the open end of the horn.
As is clear from what has been proposed (as shown in the figure), this is already a known fact. This is thought to be because the radio waves incident on the protrusion of the dielectric are refracted, resulting in a path difference depending on the incidence fr1. In other words, a radio wave that is incident on a protrusion of a dielectric at a large angle of incidence is
The path difference is larger than that of radio waves incident at a small angle of incidence,
I asked Party B to reduce Zydrobe due to this path difference.
Form a main lobe with strong horns.

In the above embodiment, since the dielectric body 3 has a dual structure inside and outside, the main beam forming effect of the dielectric body 3 is further strengthened, and it is considered that the vertical directivity is thereby further improved.

<Effects of the Invention> As described above, according to the present invention, a dielectric body having a forward protrusion is provided at the open end of the pawn, and the dielectric body has a dual structure inside and outside, thereby improving vertical directivity. Therefore, excellent vertical directivity can be obtained without increasing the aperture size of the pawn or the forward protrusion size of the dielectric. Therefore, the space occupied by the antenna as a whole becomes smaller, making it possible to make it smaller and lighter. When used as a radar antenna, the drive means such as a swing drive motor can be simplified and made smaller.

In addition, since the dielectric has a dual structure inside and outside, the dielectric can be attached to the pawn via the double portion to strengthen the connection between the dielectric and the horn.

Note that by filling a foaming agent such as foamed urethane between both the inner and outer dielectrics, the entire dielectric is reinforced and accidental deformation is prevented.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, and FIGS. 2 to 4 are longitudinal sectional views of conventional examples. 1: Slot waveguide, 2: Horn, 3: Dielectric, 3a: Arc portion, 3b: Projection, 31: Inner dielectric, 3o: Outer 1 dielectric.

Claims (1)

[Claims] (1) A dielectric is attached to the open end of a horn having a slot waveguide at its base in a shielding manner, and the dielectric has a protrusion that protrudes forward at the vertical center position, and the dielectric A slot array antenna device characterized by having an inner and outer double structure with an air layer or a filling layer sandwiched therebetween.