JPH0969726A - Plane antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the easing of a plane antenna from its internal pressure by making the inside air of the casing flow in and out through a venthole. SOLUTION: A converter 6 is fixed to the rear side of a easing 1, and a venthole 15 is formed at the lower edge part of the converter 6 on the rear side of the casing 1. At the same time, the swelling parts 12 and 12 are prepared at both sides of the lower edge of the converter 6 and along the rear side of the easing 1. Then a connector 10 protrudes from the converter 6 toward a point right above the venthole 15 and also a dust cover 16 entirely covers the converter 6 and the venthole 15 on the rear side of the casing 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a converter integrally fixed to the back surface of a planar box having a built-in element such as a radial waveguide or a microstrip.
The present invention relates to a planar antenna suitable for the EHF band.

[0002]

2. Description of the Related Art In a planar antenna using a radial waveguide as an element, a dielectric such as foamed resin is housed in a box so that the element is regulated at a fixed position in the thickness direction. The box is composed of a main body on the back surface side and a cover on the front surface side, and at least the cover is designed to meet the requirement of not blocking the transmission of radio waves. There is a small space between the peripheral edge of the dielectric and the peripheral surface of the box, and since the dielectric itself contains air bubbles, the box holds a considerable amount of air inside. The same applies to the microstrip antenna.
With antennas that are often used outdoors, the temperature changes drastically, such as when exposed to direct sunlight and the temperature rises, and conversely the temperature drops to below freezing and the temperature drops, causing the internal air to expand or Contract. If the box has a completely closed structure, the internal pressure of the box changes due to the expansion or contraction of the air, and as a result, for example, as shown in FIG. Not only deteriorates the waterproof property, but also deteriorates the waterproof property, and rainwater invading from there is likely to cause dew condensation inside, and the element is corroded by the rainwater, and the antenna characteristics are likely to be deteriorated. Therefore, in the related art, there has been an attempt to adjust the pressure of the box body by forming ventilation holes in the peripheral edge of the box body as described in, for example, JP-A-4-54707.

[0003]

In the structure in which the ventilation holes are formed in the peripheral edge of the box, the ventilation holes are formed in the peripheral edge portion of the box although air flows in and out through the ventilation holes to keep the internal pressure constant. Therefore, it is unprotected against rainwater and cannot prevent the intrusion of rainwater, resulting in the same result as an antenna having a crack in the cover. Therefore, as described in JP-A-4-54707 and Japanese Utility Model Application Laid-Open No. 5-59940, there is proposed a means for attaching a gas permeable membrane to the vent hole, but for an antenna arranged outdoors, Since dust and dirt adhere to the surface, the rainwater containing the dust will remain on the gas permeable membrane as it passes through the surface of the gas permeable membrane, and it will stick to the surface and block the ventilation holes, impairing the pressure adjustment function. I will end up. The present invention, by a rational configuration,
The purpose is to prevent rainwater from entering through the ventilation holes.

[0004]

The structure of the present invention is, in the installed state, a planar antenna in which a ventilation hole is provided on the back surface of the box which is at the lower edge of the converter. In such a planar antenna, the converter is On both sides of the lower edge, a bulging portion is formed so as to extend along the back surface of the box body, an output terminal is projected from the converter in a direction passing directly above the ventilation hole, or at least around the ventilation hole. It is effective to provide an eaves body that covers the upper half of the opening, or to provide a dust cover that integrally covers the converter and the ventilation hole on the back surface of the box body.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described with reference to the drawings. FIG. 1 shows a cross section of the planar antenna, and FIG. 2 shows the back surface thereof, respectively.
And a cover 1b fitted so as to cover the opening surface of the main body 1a form an inner hollow disk-shaped box 1, and inside the box 1, a slot plate 2 is provided with dielectrics 3,4. It is housed in a state of being sandwiched between. The main body 1a is made of a conductive material such as a galvanized steel plate or an aluminum plate, and functions as a ground plate. Further, the dielectric 3 arranged between the main body 1a and the slot plate 2 functions as a wave retarding member for shortening the wavelength of the signal.
The dielectric 4 disposed between the cover 1b and the cover 1b restricts the slot plate 2 to a fixed position in the thickness direction, that is, the cover 1
Expanded polystyrene is preferably used as the dielectrics 3 and 4 because it plays a role of keeping a constant distance from b. Further, the cover 1b functions as a radome, for example, AES (acrylonitrile / ethylene propylene rubber /
It is made of a material such as styrene) resin or ABS (acrylonitrile / butadiene rubber / styrene) resin that has excellent weather resistance and does not impair radio wave transmission while maintaining strength against wind and rain and snow. By the way, the thickness of an antenna having a box diameter of several tens of cm is about 1.5 mm.

The box 1 is hermetically sealed by embedding a sealing material 5 around the entire circumference of the body 1a and the cover 1b, and a converter is provided on the back side (body side) of the box 1. 6
And the mounting bracket 7 are fixed. Converter 6
Is adhered to the main body 1 through a packing material such as silicon rubber, and through a through hole 8 formed in the main body 1, a feeding point at the center of the slot plate 2 and an internal circuit (not shown). 2) is connected by a probe 9, and the gap between the through hole 8 and the probe 9 is sealed to completely seal the internal circuit to protect the internal circuit. As the probe 9, a metal having excellent conductivity is used,
For example, a rod-shaped body made of brass plated with gold is used. Further, from the lower position of the converter 6, a connector 10 as an output terminal is provided so as to project obliquely downwardly away from the box body in the mounted state (hereinafter, the expressions of “upper” and “lower” mean the positional relationship in the mounted state). The thin-walled screw fastening portions 11, 1 are provided on both sides of the upper and lower edges of the converter 6 and both side edges.
1 ... is formed, and in particular, screwed seats 11, 11 at the lower edge
Has bulged portions 12 and 12 protruding downward along the back surface. A cylindrical portion 13 for fitting a waterproof cap and a draining cylinder 14 are provided at the protruding base end portion of the connector 10.
Are provided coaxially with the connector, and a vent hole 15 is provided in the main body (the back surface of the box) which is the lower edge of the converter 6, and a gas passage film 15a is attached to the vent hole 15. There is. A dust cover 16 having a round window 16a exposing the connector 10 is attached to the back surface of the box 1 so as to integrally cover the converter 6 and the ventilation hole 15.

The planar antenna is, for example, as shown in FIG.
The receiving surface (surface) is fixed to the pillar 17 via the mounting bracket 7 with the receiving surface (surface) facing the satellite, the coaxial cable 18 as a transmission line is connected to the connector 10, and the waterproof cap 19 is connected to the connector 10. It is installed by mounting.

In the planar antenna thus formed, the internal circuit of the converter is completely sealed and the connecting portion between the cable and the connector is also covered with the waterproof cap. When the internal air becomes hot and expands, or when it cools and contracts,
Vents formed on the back surface allow air to flow in and out, the internal pressure is automatically adjusted, and the internal pressure does not act on the box. Rainwater that has fallen on the surface of the box flows down along the surface of the box, and rainwater that circulates on the back side splits into the left and right sides of the converter, and at that time, the rainwater that flows down the backside projects to both sides of the lower edge of the converter. It is blocked by the formed bulge and does not go around to the center side where the ventilation hole is located. Also, if you encounter horizontal rain etc. and rainwater also pours directly on the back side, most of the rainwater can be blocked with a dust cover, but since the dust cover is only installed as a dust protection measure, there is no waterproof measure. Although complete, a connector is located at the top of the ventilation hole and a cable with a waterproof cap is connected to the connector, so those cables block rainwater and rainwater falls into the ventilation hole. Never with the water on the dust cover,
It flows down the coaxial cable and is prevented from entering the vent hole.

Further, the dust cover prevents dust from being attracted to the periphery of the vent hole, and in particular, when a gas passage membrane is attached to the vent hole, it is easily blocked by dust. The dust will not clog the vents, and the cover will cover the converter for a beautiful look.

Further, as shown in FIG. 5, if an eaves body 20 for covering the upper half of the opening is provided around the ventilation hole 15,
The vent holes are protected from rainwater and dust, as in the case where the bulging portions are formed so as to project on both sides of the lower edge of the converter, and the connector is provided so as to project in a direction passing directly above the vent holes. The eaves body 20 can be formed separately from the main body 1a and fixed to the main body 1a, or the main body 1a can be pressed to be integrally bulged into the main body.

In the embodiment, the main body is made of metal and is also used as the ground plate. However, a structure in which the metal plate is arranged on the inner surface of the main body made of synthetic resin may be used. In addition to line slot antennas, it is also applied to microstrip antennas, and the shape of the box is not limited to a disk shape, but any shape that is planar, such as a polygonal shape or a peculiar shape such as a petal shape. You can also

Further, in the embodiment, the bulging portion formed to overhang the converter also serves as a screwing portion, but this bulging portion may be provided independently, or the protruding direction of the output terminal may be changed. There is no problem even if the dust cover is omitted, and the essential point is that the vent hole is formed at the lower edge of the converter.

[0013]

According to the present invention, the internal pressure is automatically adjusted as the air inside the box moves in and out through the vent, so that the box is not damaged and the vent is located near the lower edge of the converter. Since it is located at the bottom, rainwater does not easily enter, and if bulging parts are provided on both sides of the lower edge of the converter so that it is located on both sides of the vent hole, rainwater that flows down the back surface by these bulging parts will enter. If the output terminal is projecting diagonally downward, the upper part of the ventilation hole is blocked by cables, so that it does not descend even during heavy rain, and an eave separate from these is formed, or By putting them together with the eaves,
The effect of preventing rainwater intrusion is further improved. Furthermore, by mounting the dust cover, it is possible to prevent clogging of the vent holes due to dust, and the protection measures for the vent holes are perfect.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a planar antenna according to the present invention.

FIG. 2 is an explanatory view showing the back surface of the planar antenna according to the present invention.

FIG. 3 is an explanatory diagram of an installed state.

FIG. 4 is an explanatory diagram showing a state where rainwater flows down.

FIG. 5 is an explanatory diagram of a modification example.

FIG. 6 is an explanatory diagram of a cover damaged by a change in internal pressure.

[Explanation of symbols]

1 ... Box, 1a ... Main body, 1b .. Cover, 2 ... Slot plate, 3, 4 ... Dielectric material, 5 ... Sealing material, 6 ...
Converter, 7 ... Mounting bracket, 8 ... Through hole, 9 ...
Probe, 10 ・ ・ Connector, 11 ・ ・ Screw stopper, 1
2 ... Bulging part, 13 ... Cylinder part, 14 ... Drainer, 15
..Ventilation holes, 16 ... Dust covers, 17 ...
8 ... Coaxial cable, 19 ... Waterproof cap, 20 ...
Eaves, 21 ... Cracks.

Claims (5)

[Claims] 1. A planar antenna in which a converter is integrally fixed to the back surface of a planar box having a built-in element, the planar antenna having a ventilation hole on the back surface of the box at the lower edge of the converter in the installed state. Antenna. 2. The planar antenna according to claim 1, wherein bulging portions are formed so as to extend along the back surface of the casing on both sides of the lower edge of the converter. 3. The planar antenna according to claim 1, wherein an output terminal is provided so as to project from the converter in a direction passing directly above the ventilation hole. 4. The planar antenna according to claim 1, further comprising an eaves body which surrounds at least the upper half of the opening around the ventilation hole. 5. A dust cover that integrally covers the converter and the ventilation hole is provided on the back surface of the box.
The planar antenna according to any one of 1.