JPH0474005A - Reflection type antenna - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a reflection antenna mainly used for transmitting and receiving signals that develop frequencies higher than SHF.

<Conventional technology> For example, in earth station antennas for transmitting and receiving radio waves for satellite broadcasting and antennas for communication between satellites, reflection antennas, such as lens antennas using dielectric lenses and parabolic antennas, have traditionally been used. type antenna is used.

Figure 5 is a conceptual diagram showing the basic configuration of a dielectric lens antenna, in which a spherical wave from a primary horn 3 with a feeder 2 placed at the focal point of the dielectric lens 1 is converted into a plane wave by the dielectric lens 1. In this way, a high-gain antenna is achieved.

On the other hand, FIG. 6 is a conceptual diagram showing the basic configuration of a parabolic antenna, in which a spherical wave is radiated from a primary radiator 12 placed at the focal point of a metal reflector 11 having a paraboloid of revolution. The waves are converted into plane waves by the metal reflector II. Radio waves are applied to the -order radiator 12 via a waveguide 13.

<Problems to be Solved by the Invention> In the above-mentioned dielectric lens antenna, as shown in FIG. 5, the antenna depth is long, so the antenna becomes large and requires a large space for installation.

On the other hand, with a reflective antenna, the antenna depth is not very long, but it is necessary to press-manufacture a metal reflector with a paraboloid of revolution, and it is difficult to press-manufacture a reflector with a complex shape. Moreover, the larger the antenna, the more expensive the brace mold becomes, which makes it even more expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned technical problems and to provide a reflective antenna which is small in size and has a reduced production cost.

Means for Solving the Problems> As shown in FIG. 1, the reflective antenna of the present invention has a dielectric lens 22 on one surface of a flat reflector 21, one surface 22a of which is spherical and the other surface of which is flat. The flat side of the dielectric lens 2 is fixed, and a radiator 23 is placed at the focal point of the dielectric lens 2.

<Operation> The spherical wave emitted from the radiator 23 is transmitted through the dielectric lens 22
After being refracted at the surface 22a, it is reflected at the surface of the plane reflection plate 21, and then subjected to a second refraction at the surface 22a, where it is converted into a plane wave.

Since this configuration has the basic configuration as a reflective antenna, the antenna depth E is the antenna depth when a normal lens antenna is configured without using the reflector 21! ', and there is no need for a reflector with a complicated shape such as a paraboloid of revolution.

<Example> Embodiments will be described in detail below with reference to the accompanying drawings showing examples.

FIG. 2 is a sectional view showing the basic configuration of a reflection antenna according to an embodiment of the present invention. In this embodiment, a Cassegrain antenna is constructed as an application of the basic construction of the present invention shown in FIG. 1 above. In other words, the plane reflector 3
A dielectric lens 32 is attached to one surface of the dielectric lens 1, and a primary radiator 33 is arranged on the axis of the dielectric lens 32.

A sub-reflection plate 34 having a hyperboloid surface convex toward the -order radiator 33 is provided opposite to the -order radiator 33 . This sub-reflector 34 is fixed to the radome 35.

In this configuration, due to the function of the sub-reflector 34, the configuration is equivalent to arranging a primary radiator at the focal point 36 of the dielectric lens 32.

The spherical wave radiated from the primary radiator 33 is transmitted to the sub-reflector 34
The light is reflected and guided to the dielectric lens 32. 1st above
As is clear from the description of the figures, the dielectric lens 32
And flat reflector 3! The above-mentioned sub-reflector 3 works together to achieve the same effect as a metal reflector having a paraboloid of revolution.
The spherical wave from 4 is converted into a plane wave and propagates through the radome 35.

The same goes for reception, where the plane wave passes through the dielectric lens 32.
The wave is then converted into a spherical wave by the plane reflector 31, converged from the sub-reflector 34 to the primary radiator 33, and received.

In this configuration, since the radio wave path is folded back, the antenna depth length fl becomes even shorter than the configuration shown in FIG. Furthermore, since radio waves can be refracted twice on the surface 32a of the dielectric lens 32, the thickness of the dielectric lens can be reduced by half compared to conventional lens antennas.
This can contribute to thinner and lighter weight. Furthermore, with this configuration, the -order radiator 33
It can be directly connected to the transmitter/receiver (in other words, no waveguide for power supply is required), so you can easily connect it to the transmitter/receiver. It also has the advantage of reducing losses.

Also, a large reflector with a paraboloid of revolution is not required,
Since only the plane reflecting plate 31 and the small sub-reflecting plate 34 are required, there is no need for a costly large mold, and the production cost can be significantly reduced. Furthermore, the radome 35 provides a well-arranged appearance and shape, and can eliminate the effects of snow accumulation. Therefore, it is particularly effective when used as an earth station antenna or receiving antenna for satellite broadcast transmission that needs to be directed upward.

FIG. 3 is a sectional view showing the basic configuration of another embodiment of the present invention. This antenna is a so-called Gregorian antenna by applying the configuration shown in FIG.
is fixed, and a primary radiator 43 is arranged on the axis of this dielectric lens 42. A sub-reflector 44 having a concave elliptical surface facing the -order radiator 43 is arranged opposite to the -order radiator 43.

- The spherical wave radiated from the secondary radiator 43 is transmitted to the secondary reflector 43.
The path is reflected at the focal point 4 of the dielectric lens 42.
5 and then guided to the dielectric lens 42. The dielectric lens 42 and the plane reflector 41 convert the wave into the spherical wave or the plane wave, as in the first embodiment. The same holds true for reception; a plane wave is converted into a spherical wave by the dielectric lens 42 and the plane reflector 41, and this spherical wave is converged on the primary radiator 43. 46 is a radome.

In this embodiment, the function of the sub-reflector 43 realizes a configuration equivalent to arranging a -order radiator at the focal position 45.

FIG. 4 is a conceptual diagram showing the basic configuration of still another embodiment of the present invention. This antenna is configured as a so-called offset antenna by applying the configuration of the first embodiment described above. That is, a dielectric lens 52 is fixed to one surface of a flat reflector 51, and these lenses perform the same function as a metal reflector having a shape obtained by taking out a part of a paraboloid of revolution. Then, a focal point position 5 located outside the antenna radiation axis 53
At 7, a primary radiator 54 is placed opposite the dielectric lens 52. The radiation axis 55 of this -order radiator 54 and the antenna radiation axis 53 are obliquely intersecting.

56 is a support member for supporting the -order radiator 54.

With this configuration, the spherical wave from the -order radiator 54 is converted into a plane wave by the dielectric lens 52 and the plane reflector 51, as in each of the above embodiments, or the -order Since scattering of radio waves by the radiator is prevented, this has the advantage of reducing side lobes. The same applies to reception.

Note that the present invention is not limited to the above-mentioned embodiments. For example, in the above embodiment, one surface of the dielectric lens attached to the reflection plate is spherical, and the other surface is flat, but both surfaces may be spherical. Various other design changes can be made without changing the gist of the present invention.

<Effects of the Invention> As described above, according to the reflective antenna of the present invention, the plane reflector and the dielectric lens work together to achieve the same effect as a metal reflector having a paraboloid of revolution. Unlike conventional reflective antennas, there is no need for a mold to create a complex-shaped reflector, which significantly reduces costs. Moreover, since it has the basic configuration as a reflection antenna, the antenna depth is short, which contributes to miniaturization. Furthermore, since a reflector is used, the radio waves can be refracted twice in the dielectric lens, thereby making it possible to reduce the thickness of the dielectric lens. This makes it possible to reduce the weight compared to conventional lens antennas.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing the basic configuration of a reflection antenna according to the present invention, FIG. 2 is a sectional view showing the basic configuration of a reflection antenna according to an embodiment of the invention, and FIG. 4 is a sectional view showing the basic configuration of still another embodiment of the present invention, and FIG. 5 is a sectional view showing the basic configuration of a conventional lens antenna. Conceptual diagram showing the structure. FIG. 6 is a perspective view showing the basic structure of a conventional reflection antenna. 21... Planar reflection plate, 22... Dielectric lens, 23
...Radiator, 31,41.51...Flat reflector, 3
2゜42.52...Dielectric lens, 33.43.54
--Next radiator 21--Flat reflecting plate 22--Dielectric lens 23--Radiator 31--Flat reflecting plate 32--Dielectric lens 33--Nth radiator 41.51 -・Flat reflector 42, 52...Dielectric lens 43.54...-order radiator

Claims (1)

[Claims] 1. A reflective antenna comprising a flat reflector, a dielectric lens attached to one surface of the flat reflector, and a radiator placed at the focal point of the dielectric lens.