JPH0332087Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention relates to a primary radiator in a parabolic antenna or an offset antenna for circularly polarized waves.

<Prior Art> Conventionally, a feedhorn as shown in FIG. 3, for example, has been used to radiate circularly polarized waves toward a reflector or to capture circularly polarized waves collected by a reflector. In the figure, 1 is a circular waveguide;
A horn 2 is formed at one end, a flange 3 is formed at the other end, and a 90° phase shifter 4 made of a dielectric plate inclined at 45° to the plane of the paper and an absorption resistance plate 5 parallel to the plane of the paper are provided inside. It is being

Circularly polarized waves include left-handed circularly polarized waves and right-handed circularly polarized waves, and the one shown in the third figure is a feedhorn for right-handed circularly polarized waves. The only difference in the feed horn for left-handed circularly polarized waves is that the mounting angle of the absorption resistor plate 5 is perpendicular to the plane of the paper, rather than parallel to the plane of the paper as shown in Figure 3, and the rest of the structure is for right-handed circularly polarized waves. It is exactly the same as the feed horn for use.

<Problems to be solved by the invention> As mentioned above, the feed horns for right-handed circularly polarized waves and left-handed circularly polarized waves have only a slight difference in structure, but they perform opposite actions, so they can be used separately. It has to be produced, which increases production costs. In addition, when stockpiling products, both must be kept separately.

<Means for solving the problem> The feedhorn of this invention, like the conventional feedhorn with a circular polarizer described above, has a horn at one end of the circular waveguide and a 90° phase shifter in the center part. and has an absorbing resistance plate inside the other end.
A feature of this invention is that the absorption resistance plate is not fixed inside the circular waveguide, but is placed in one of the four grooves formed at 90° intervals on the inner surface of the circular waveguide parallel to the tube axis.
Both edges are slidably fitted into the opposing parts.

<Operation> In this invention, when the absorbing resistance plate is inserted and supported by the first pair of opposing grooves, the feed horn operates for right-handed circularly polarized waves. Next, when the absorbing resistor plate is removed from the first pair of grooves and supported by the second pair of grooves, the absorbing resistor plate assumes a posture 90° different from that for right-handed circularly polarized waves.
The feedhorn operates for left-handed circularly polarized waves.

<Example> In FIGS. 1 and 2, 1 is a circular waveguide having a horn 2 at one end and a flange 3 at the other end. Inside the central part, a 90° phase shifter 4 made of a dielectric plate is installed at an angle of 45° to the plane of the paper, but various types of 90° phase shifters are also available. It can also be used. From the end of the circular waveguide 1 on the flange 3 side, grooves 6a, 6b, 6c, and 6d parallel to the tube axis are formed inward on the inner wall at intervals of 90 degrees. Both side edges of the absorption resistance plate 5 are supported by grooves 6a and 6c or 6b and 6d.

In the above feedhorn, 90° phase shifter 4
converts left-handed circularly polarized waves into vertically polarized waves in the plane of the paper, and converts right-handed circularly polarized waves into polarized waves in the direction perpendicular to the plane of the paper. Therefore, when the absorbing resistance plate 5 is supported perpendicularly to the plane of the paper by the grooves 6b and 6d as shown in FIG. Only waves are received. On the contrary, the second
As shown in the figure, when the absorption resistance plate 5 is supported parallel to the plane of the paper by the grooves 6a and 6c, only right-handed circularly polarized waves are received in order to absorb polarized waves parallel to the plane of the paper. be done.

Note that even if the orientation of the absorption resistor plate 5 remains the same and the orientation of the 90° phase shifter 4 is changed by 90°, the feed horn can be changed for left-handed circularly polarized waves and right-handed circularly polarized waves in the same way. However, since the 90° phase shifter 4 is located deep within the waveguide 1, it is disadvantageous to switch its position.

<Effects of the invention> As described above, this invention utilizes the four grooves provided on the inner surface of the end of one circular waveguide,
The posture of the absorption resistance plate supported by a pair of grooves is
By changing the angle by 90°, the same feed horn can be switched and used for right-handed circularly polarized waves and left-handed circularly polarized waves. Therefore, with a simple configuration of providing four grooves in one circular waveguide, it is possible to switch and receive right-handed circularly polarized waves and left-handed circularly polarized waves, streamlining production and stocking of products. It can contribute to lowering product prices.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view and an end view of an embodiment of this invention when used for left-handed circularly polarized waves, and Fig. 2 is a longitudinal sectional view and an end view of the embodiment when used for right-handed circularly polarized waves. The end view and FIG. 3 are longitudinal cross-sectional views of a conventional right-handed circularly polarized feed horn. 1... Circular waveguide, 2... Horn, 3... Flange, 4... 90° phase shifter, 5... Absorption resistor plate, 6
a~6d...Groove.

Claims (1)

[Scope of utility model registration request] A circular waveguide that has a horn at one end, houses a 90° phase shifter inside, and has four grooves parallel to the tube axis formed at 90° intervals on the inner surface from the other end toward the one end. , a feed horn with a circular polarizer comprising an absorbing resistor plate which is plate-shaped and whose both side edges are slidably fitted into the opposing grooves.