JPS63966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horn antenna such as a conical horn antenna or a pyramidal horn antenna used in a microwave band or a millimeter wave band.

Conventionally, such horn antennas are shown in Figures 1 and 2.
As shown in the figure, it consisted of a conical or pyramidal horn 1 and a feeding waveguide 2. When using such a horn antenna outdoors, it is necessary to attach an opening cover to prevent water droplets from entering due to rain or the like, or to prevent snow from accumulating inside the horn.
Conventionally, such an aperture cover is made by placing a thin dielectric film 3 made of Teflon or the like over the aperture, and then covering the dielectric film with a ring 4 made of a metal plate or dielectric plate, as shown in FIG. The presser ring was attached to the horn with a number of screws 5. If even more sufficient airtightness is required, the above-mentioned dielectric The body membrane 3 and the opening surface of the horn were brought into close contact. Therefore, in this structure, the horn opening cover is attached with a large number of screws, making it difficult to remove it. The thickness of the wall of the horn needs to be increased due to the cutting of grooves in the cross section of the wall on the opening side of the horn and the drilling of screw holes for screw fixing, which increases the weight of the horn. Furthermore, a ring attached to the opening of the horn to press down the dielectric film deteriorates the electrical performance of the horn.

In order to eliminate these drawbacks, the present invention changes the shape of the opening of the horn antenna and changes the method of attaching the opening cover, and will be described in detail below with reference to the drawings.

FIG. 4 shows an embodiment of the present invention, which is composed of a conical horn 1, a feeding waveguide 2, a dielectric film 3, and a band 9. A sectional view of the opening of the horn antenna according to the embodiment of the present invention is shown in FIG. 5a. A ring 8 having a triangular cross section is attached around the opening of the conical horn 1 so that the apex of the triangle coincides with the opening surface and one side of the triangle is in close contact with the outer wall of the horn. It has a structure in which a groove 6 is provided in a part of the outer side in the circumferential direction of the horn. A dielectric film 3 larger than the size of the opening is placed over the horn opening and the ring 8 attached to the outside of the opening, and a band 9 made of metal or dielectric is fitted into the groove 6 from the outside of the dielectric film 3. The dielectric film 3 is fixed in the opening by applying the same. Therefore, by having such a configuration,
Advantages include that the dielectric film 3, which is the aperture cover, can be easily removed, and that screw hole grooves are not required on the wall on the aperture side of the horn, allowing the outer wall to be thinner and the horn to be lighter. There is. Furthermore, since there is no ring for pressing the dielectric film at the opening of the horn and the thickness of the horn at the opening can be made thinner, the influence of these parts on the electrical performance of the horn can be reduced.

FIG. 5b is a diagram showing another embodiment of the present invention,
In the groove 6 shown in FIG. 5a, two grooves 6a and 6b parallel to the groove 6 are provided. Rubber rings 7 are inserted into the grooves 6a and 6b as packing material.
A and 7b are included. With such a structure, the horn 1 and the dielectric film 3 can be brought into close contact with each other, and the inside of the horn can be kept sufficiently airtight. Although the case where there are two grooves for inserting the packing material is shown here, the same effect can be obtained even if there are one or three or more grooves.

Furthermore, if pressure is applied to the inside of the horn antenna having such a structure, the dielectric film 3 will swell outward as shown in FIG. Therefore, in this case, the dielectric film 3 has a substantially spherical shape, which is closer to the wavefront of the radio waves radiated from the horn 1 than when it is flat.
It has the advantage of reducing reflection from

The above explanation is about a case where a ring with a triangular cross section is attached to the opening of a conical horn with a wall of uniform thickness, but the same applies to a structure in which the wall and ring of a conical horn are integrated. effect can be obtained. Furthermore, similar effects can be obtained even when this invention is applied to a pyramidal horn.

As explained above, according to the present invention, since the aperture cover is attached with a band, the aperture cover can be easily removed, the thickness of the horn can be reduced, so the horn can be made lightweight, and the aperture cover can be easily removed. There is an advantage that the influence of the cover and the attachment parts of the aperture cover on the electrical performance of the horn can be reduced.

[Brief explanation of the drawing]

Fig. 1 and Fig. 2 are block diagrams of a conventional horn antenna, Fig. 3 is a diagram showing a conventional method of attaching an aperture cover, Fig. 4 is a block diagram of a horn antenna of the present invention, and Fig. 5 is a block diagram of the present invention. FIG. 6 is a cross-sectional view of the opening of the horn according to FIG. 6, and is an explanatory view of one effect of the present invention. In the figure, 1 is a horn, 2 is a feeding waveguide, 3 is a dielectric film, 4 is a ring, 5 is a screw, 6 is a groove, 7 is a packing material, 8 is a ring, and 9 is a band. In the drawings, the same or corresponding parts are denoted by the same reference numerals.

Claims (1)

[Claims] 1. In a horn antenna used in the microwave band or millimeter wave band, a horn having a uniform thickness is provided with a ring having a triangular cross section, and the apex of the triangle coincides with the aperture surface. One side of the triangle is provided in close contact with the outer wall of the horn, and a groove is provided in a part of the outer side of the triangle in the circumferential direction of the horn, and a dielectric film is placed over the opening and ring of the horn. A horn antenna characterized in that a band made of metal or dielectric is applied from the outside to fit into the groove, and the dielectric film is attached to the opening of the horn. 2. In the groove of the opening of the horn, a groove smaller in width than the above-mentioned groove is provided so as to be parallel to the groove of the opening of the horn, and a packing material such as rubber is placed in the small-width groove. 2. The horn antenna according to claim 1, wherein the inside of the horn is sealed. 3. The horn antenna according to claim 1 or 2, wherein the horn and the ring have an integral structure.