JPH03123104A - Antenna equipment - Google Patents

Abstract

PURPOSE:To obtain a frequency selective sub-reflecting mirror whose structure is simple and whose loss is small by constituting the sub-reflecting mirror of a metallic specular surface, a frequency selective metallic filter and each one layer or a dielectric sheet layer and a dielectric core layer. CONSTITUTION:A ray 6a passes through a frequency selective metallic filter 22a, a dielectric sheet layer 23a and a dielectric core layer 24a of a sub- reflecting mirror, reflected by a metallic specular surface 21, passes through the core layer 24a, the sheet layer 23a and the filter 22a again and goes to a main reflecting mirror. In this case, by making thickness of the dielectric core layer 24a constant, and changing thickness of the dielectric sheet layer 23a, adjustment of a phase is executed. As for thickness 3b, the larger an incident angle theta to the sub-reflecting mirror of the ray 6a is, the thicker it is, and the smaller theta becomes, the thinner it becomes. In such a way, the number of components is small and the equipment can be manufactured easily, and also, by adjusting the thickness of the dielectric sheet layer, the loss of a passing ray is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure of an antenna mirror surface having frequency selectivity.

[Conventional technology]

An example of the conventional technology will be described with reference to FIG.

Figure 3(a) shows the antenna configuration, and Figure 3(b) shows an enlarged cross-sectional view of the sub-reflector, where 1 is the main reflector, 2 is the frequency-selective sub-reflector, and 21 is a metal mirror surface. , 22a, '22
b is a frequency selective metal filter having frequency selectivity; 23a and 23b are frequency selective metal filters 22;
A and 22b are supported by dielectric sheet layers, and 24a is a dielectric core layer. 24b is a dielectric core layer that supports the metal mirror surface 21 and the frequency selective metal filter 2'2b.

3a indicates the thickness including the dielectric sheet layers 23a, 23b and the dielectric core layer 24a.

4.5 are feeding horns that operate at the frequency ft-fR, and 6a to 6c and 7a to 7c are central rays (simply referred to as "rays") of radio waves emitted from the feeding horns 4 and 5, respectively.
).

6a is a ray heading from the feeding horn 4 to the sub-reflector 2, 6b
, 61a, and 61b are reflected rays that are reflected by the σ reflector, and 6b is a necessary ray, and 61a
, 61b is the frequency selective metal filter 22a* or 2
This is an unnecessary wave reflected by 2b.

Next, the operation of the antenna shown in FIG. 3 will be explained.

The ray 7a emitted from the feeding horn 5 is reflected by the frequency selective metal filter 22a and is directed toward the main reflecting mirror 1.

In addition, Raylo a radiated from the power feeder 4 is transmitted through the frequency selective metal filter 22a and the dielectric sheet layer 23a.
, passes through the dielectric core layer 24a, is reflected by the metal mirror surface 21, and is again dielectric core layer 24a and dielectric sheet layer 23a1.
It passes through the frequency selective filter 22a and heads toward the main reflection *i.

In this way, by using a frequency-selective mirror surface, 1
Since two frequencies can be used at the same time on a set of antenna mirror surfaces, it is often used in cases where there is a limit to the weight that can be mounted, such as in antennas mounted on satellites.

Here, unnecessary waves 61. In order to cancel out unnecessary waves 611), the thickness 3a is approximately λT so that the phase difference is an odd multiple of λt/2 (the wavelength of the wave with frequency ft is λT).
The thickness is determined to be an odd multiple of /4, and the thickness is uniform.

[Problem to be solved by the invention]

As explained above, in the structure of the sub-reflector shown in FIG. 3(I), the dielectric core layer 24a.

24I), frequency selective metal filter 228!221
) and dielectric sheet) N23a, 23b, etc., the number of layers is large, the manufacturing process is complicated, and the required precision cannot be ensured.

Therefore, the problem to be solved by the present invention is to configure a frequency selective sub-reflector with a simple structure and low loss.

[Means to solve the problem]

According to the present invention, the above-mentioned +1 objective is achieved by the means described in the scope of the patent application.

3-4 That is, the present invention provides an antenna consisting of a main reflecting mirror, a sub-reflecting mirror, and a feeding horn, in which the sub-reflecting mirror has a metal mirror surface, a frequency-selective metal filter, and a frequency-selective metal filter. The antenna device comprises a dielectric sheet layer holding a dielectric sheet layer; .

Hereinafter, the effects of the present invention will be explained based on Examples.

〔Example〕

[Dog] Example 1 - ± = tpJJ The diagram is the first embodiment of the present invention, and is an example in which the thickness of the dielectric core/l 24 a is non-uniform.

Also, only an enlarged view of the sub-reflector is shown, and other parts of the antenna, the main reflector and the feeding horn are omitted because they are the same as in FIG. 3.

Note that each symbol is the same as in the $3 diagram.

The operating principle of this embodiment will be described below.

Since the reflected rays 7a and 7b are the same as those shown in FIG. 3(b), their explanation will be omitted.

Raylo a passes through the frequency selective metal filter 22a, the dielectric sheet layer 23a, and the dielectric core layer 24a, is reflected by the metal mirror surface 21, and passes through the dielectric core layer 24aS, the dielectric sheet layer 23a, and the frequency selective metal filter 22a again. Pass through and head towards the main reflector.

Here, 61c is a reflected ray at the frequency selective metal filter 22a. Reflection on metal mirror surface 21 b
The thickness 3b of the dielectric sheet layer 23a and the dielectric core layer 24a is determined so that the phase difference between the reflective Reiro b and the reflective Reiro 1c is an integral multiple of λ so that the transmission loss of the dielectric core layer 24a is not deteriorated.

Here, the phase is adjusted by keeping the thickness 23a of the dielectric sheet layer constant and changing the thickness 24a of the dielectric core layer.
The larger θ is, the thicker it is, and the smaller θ is, the thinner it is.

Figure 2 shows a second embodiment of the present invention, and is an example in which the thickness 23a of the dielectric sheet layer is non-uniform.

Also, like FIG. 1, only an enlarged view of the sub-reflector is shown, and the other parts of the antenna, the main reflector and the feeding horn are omitted because they are the same as in FIG. 3.

Note that the reference numerals of each part are the same as in FIG. 3.

The operating principle of this embodiment will be described below.

Since the reflected rays 7a and 7b are the same as those shown in FIG. 3(b), their explanation will be omitted.

Raylo a passes through the frequency-selective metal filter 22as, dielectric sheet layer 23a1, dielectric core layer 24a, is reflected by the metal mirror surface 21, and returns to the dielectric core layer 24a, the dielectric sheet layer 2381, and the frequency-selective metal filter 22a. It passes through and heads towards the main reflector.

Here, 61c is a reflected ray at the frequency selective metal filter 22a. Reflection on metal mirror surface 21 b
In order to prevent the transmission loss from deteriorating, the phase difference between reflection Reiro b and reflection Reiro 1c is set to be an integral multiple of λ
Thickness 3b of electric sheet layer 23a and dielectric core layer 24a)
decide.

Here, the phase is adjusted by keeping the thickness of the dielectric core layer 24a constant and changing the thickness of the dielectric sheet layer 23a. The thickness 3b becomes thicker as the incident angle θ of Raylo a onto the sub-reflector becomes larger, and becomes thinner as θ becomes smaller.

〔Effect of the invention〕

According to the frequency-selective sub-reflector of the present invention, the constituent elements are a metal mirror surface, a -layer dielectric core layer, a -layer dielectric sheet layer, and a frequency-selective metal filter. Accuracy can be ensured.

7- Also, by adjusting the thickness of the dielectric sheet layer, deterioration in loss of passing rays is suppressed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a diagram showing a second embodiment of the present invention, FIG. 3(a) is a diagram showing a prior art antenna configuration, Figure (b) is an enlarged cross-sectional view of a conventional sub-reflector. 1... Main reflecting mirror, 2...
Frequency-selective sub-reflector, 21...Metal mirror surface, 22a, 22b...Frequency-selective metal filter 23a, 23b...
Dielectric sheet layer, 24a, 24b...
・Dielectric core layer, 3a, 3b...
Thickness including dielectric sheet layer and dielectric core layer, 4 ... Feeding horn operating at frequency ft, 5
...Feeding horn that operates at frequency fi, 6a
...Rays radiated from the feeding horn 4 to the sub-reflector, 6b, 6e, 61a-61c...
...Reflection ray 7a...Power supply horn 5
Rays emitted from to the sub-reflector, 7b, 7e...Reflected rays

Claims (1)

[Claims] In an antenna consisting of a main reflector, a sub-reflector, and a feeding horn, the sub-reflector includes a metal mirror surface, a frequency-selective metal filter, and a dielectric sheet layer holding the frequency-selective metal filter, and a dielectric sheet layer that holds the frequency-selective metal filter. 1. An antenna device comprising one body core layer each, the thickness of at least one of the dielectric sheet layer and the dielectric core layer being non-uniform.