JPH0546334Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a radome, which is a cover for protecting an antenna system from water droplets, wind pressure, etc. For example, the present invention is applicable to slot array antennas and various horns. It is useful as a radome for antennas, corner reflector antennas, etc.

[Prior Art] Radomes used in various antennas such as not only aircraft radars but also ship radars and ground radars are designed by arranging the radiating surface side of an outer cylinder that covers a waveguide to a part of the circumference. It is common to have a curved surface shape like this so that it can withstand wind pressure. In addition, for antennas covered with radomes,
In order to prevent the radio waves emitted from the waveguide from being diffusely reflected within the outer cylinder of the radome, disrupting the radiation pattern, and preventing standing waves from occurring within the outer cylinder and disrupting the impedance, the radiation surface of the outer cylinder is side-chilled. Sometimes it has a shape structure. This structure consists of two dielectric plates called skins sandwiching a relatively low-density dielectric called a core. Ideally, the distance between the skins should be electrically set to 1/4 wavelength so that the reflection that hits the skin It allows the waves to cancel each other out.

Now, the outer cylinder of the radome is often made of inexpensive and durable resin, and in this case it is generally manufactured by extrusion molding. However, with such a manufacturing method, it is difficult to integrally fabricate a radome having a desired curved shape and a radiating surface with a Sanderch structure with high precision. Therefore, in practice, as described in Japanese Utility Model Application Publication No. 58-43011, the radiation surface and other parts are molded separately.
These were assembled by adhesive etc.

[Problems to be solved by the invention] According to the technique described in the above-mentioned publication, there were problems that not only the structure was complicated and the manufacturing cost was high, but also the waterproofness of the adhesive assembly part was insufficient.
In order to avoid such problems, the
If the radiation surface is not made into a sandwich structure as described in Japanese Patent No. 157306, the structure of the radome will be simple, but as mentioned above, impedance and radiation pattern will be disturbed.

[Purpose of the invention] The object of the invention is to provide a durable radome with a simple structure that can provide a curved radiating surface that can withstand wind pressure with a side German arch structure, and which is inexpensive to manufacture.

[Means for Solving the Problems] In order to achieve the above object, the radome of the present invention includes an outer cylinder 7 having a radiation surface 7b shaped along a buckling deflection curve, a projection or a recess 8 inside the radiation surface 7b, and a high It is made of an elastic flat plate with high inductivity and restorability, and is held in a state bent into a curved shape along the radiation surface 7b of the outer cylinder 7 by the inside of the outer cylinder 7 and the projection or recess 8. Accordingly, it is characterized by comprising a dielectric plate 9 attached to the inside of the radiation surface 7b.

Further, a copper foil adhesive board is used for the dielectric plate 9,
A configuration may be employed in which a screen 5 for removing orthogonal polarization components is formed by etching on the copper foil.

Alternatively, the screen 5 for removing orthogonal polarization components may be printed on the dielectric plate 9 with conductive paint.

It is also possible to adopt a configuration in which a spacer 10 having a low dielectric constant is interposed between the radiation surface 7b of the outer cylinder 7 and the dielectric plate 9 having a high dielectric constant.

[Operation] The radiation surface 7b of the outer cylinder 7 has a shape that follows a buckling deflection curve, and a protrusion or recess 8 is provided inside the radiation surface 7b.

The dielectric plate 9 is made of an elastic flat plate with high conductivity and resilience, and by bending the dielectric plate 9 into a curved shape, the dielectric plate 9 is bent along the inner surface of the radiation surface 7b of the outer cylinder 7. It can be easily installed without any difficulty. At this time, the state of the dielectric plate 9 can be fixedly maintained between the inside of the outer cylinder 7 and the protrusion or recess 8 .

Since such a radome has a radiation surface having a curved shape and a sand-gerch structure, it has good wind pressure characteristics and does not cause disturbances in impedance or radiation pattern.

[Example] An example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view of a slot array antenna 2 for a radar, which has features such as the structure of a radome 1. In the figure, 3 is a slot array waveguide (hereinafter referred to as waveguide 3) that emits horizontally polarized waves.
This waveguide 3 is attached to a horn-shaped flare 4 that narrows the directivity in the vertical plane. Furthermore, a screen 5 consisting of a vertical grating is provided in front of the flare 4 to prevent deterioration of directivity characteristics by removing vertically polarized components in the emitted radio waves. It's getting old. The flare 4 is inserted and fixed inside the outer cylinder 7, which is the main body of the radome 1, via a support 6 made of foamed resin or the like.

This outer cylinder 7 has a base 7a that accommodates the flare 4.
and a curved radiation surface 7b facing the opening of the flare 4, and these parts are integrally molded into a cylindrical shape by extruding resin. The radiating surface 7b has a cross-sectional shape that follows the deflection curve when the long column at both rotating ends buckles. When the long column is buckled so that the maximum deflection becomes δ at a distance l, the deflection amount y of the long column at a distance x from one end is generally expressed by the following equation.

y=δsinπx/l That is, the radiation surface 7b of the outer cylinder 7 in this embodiment
is formed so that its vertical surface shape follows the above-mentioned curve. Projections 8 are provided integrally with the outer tube 7 at both upper and lower ends of the inside of the radiation surface 7b, and a dielectric plate 9 having a relatively high dielectric constant is engaged with the projections 8 in a bent shape. It has been stopped. The vertical surface shape of the bent dielectric plate 9 follows the same bending curve as the radiation surface 7b, and the distance between the two is set to a constant length so that each reflected wave is canceled out. ing. Moreover, a spacer 10 of relatively low conductivity made of foamed resin or the like is sandwiched between the two to prevent vibration of the dielectric plate 9 and to ensure the strength of the front portion of the radome 1.

According to this embodiment, the outer cylinder 7 is integrally molded into a cylindrical shape, and the spacer 10 and the dielectric plate 9 do not need to be molded into a particular curved shape. In addition, there is no need for gluing in these assembly processes.
The dielectric plate 9 can be easily attached to the inner surface of the outer cylinder 7 by bending it. Therefore, the structure and assembly are simple, and manufacturing costs can be kept low.
Furthermore, since the outer cylinder 7 serving as the main body has a cylindrical shape that can be extruded, a relatively long radome for an antenna can be realized at low cost. Furthermore, since the outer cylinder 7 is integrally molded into a cylindrical shape and the radiation surface 7b is a curved surface, it has high airtightness and watertightness to the outside, and the radiation surface 7b has a curved surface.
It is also possible to ensure the wind pressure resistance performance of b. In addition,
In this embodiment, protrusions 8 are provided near both ends of the inner surface of the radiation surface 7b to lock the bent dielectric plate 9 therein. However, the locking structure for the dielectric plate 9 may be a recess instead of the protrusion 8, and in short, any structure that can hold the dielectric plate 9 in a bent state along the radiation surface 7b may be used.

In the embodiment described above, the screen 5 is attached to the flare 4 as an independent component, but the dielectric plate 9
If a copper foil bonded board (so-called printed board) is used as a board and a screen is formed on the copper foil by etching, the screen 5 and its installation work can be omitted, making it simple and free from the negative effects of the radome. A slot array antenna with a unique structure can be obtained. Further, the same effect can be obtained by printing a screen on the dielectric plate 9 with a conductive paint such as conductive ink.

[Effects of the invention] The radome of the invention has an outer cylinder formed into a radiation surface shaped along a buckling deflection curve, and has a protrusion or recess on the inside thereof, and a dielectric plate having a high dielectric constant, The dielectric plate is made of an elastic flat plate with resilience and is held by the inside of the outer cylinder and the protrusion or recess in a state where it is bent into a curved shape along the radiation surface of the outer cylinder. Can be installed inside the surface.

Therefore, according to the present invention, it is possible to obtain a curved radiating surface that can sufficiently withstand wind pressure with a sanderch structure with a simple configuration, and the radiation impedance and radiation pattern are less likely to be disturbed, and the manufacturing cost is low and it is durable. It is possible to realize a radome with excellent environmental resistance performance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a buckling deflection curve. 1...Radome, 5...Screen, 6...
Support, 7... Outer cylinder, 7b... Radiation surface, 9... Dielectric plate, 10... Spacer.

Claims (1)

[Claims for Utility Model Registration] 1. Consisting of an outer cylinder 7 having a radiation surface 7b shaped along a buckling deflection curve and a protrusion or recess 8 inside thereof, and an elastic flat plate with high conductivity and resilience, A dielectric plate 9 is provided inside the radiation surface by holding the outer cylinder in a bent state in a curved shape along the radiation surface between the inside of the outer cylinder and the projection or recess. A radome characterized by: 2 Utility model registration claim 1, in which a copper foil bonded substrate is used as the dielectric plate 9, and a screen 5 for removing orthogonal polarization components is formed by etching on the copper foil.
Radome as described in section. 3. The radome according to claim 1, wherein the screen 5 for removing orthogonal polarization components is printed on the dielectric plate 9 with conductive paint. 4 Utility model registration claim 1, 2, or 3 in which a low dielectric constant spacer 10 is interposed between the radiation surface 7b of the outer cylinder 7 and the high dielectric constant dielectric plate 9 radome.