JPH04280105A - Antenna - Google Patents

Abstract

PURPOSE:To improve the gain without increasing the size of the antenna itself and a device driving the antenna itself or the like. CONSTITUTION:The antenna is provided with an antenna main body 1 from which a radio wave is sent/received and a diffraction section (ring section) provided to a front face of the antenna main body 1 and the diffraction section diffracts a radio wave sent/received from/to the antenna main body 1 to correct the effect of a phase due to a Fresnel zone caused in the radio wave propagation and selects only a radio wave signal passing through the specific Fresnel zone thereby improving the gain of the antenna main body 1 equivalently.

Description

[Detailed description of the invention]

[Object of the invention]

0002

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to antennas used in satellite communication systems and the like.

[Summary of the Invention] The present invention corrects the phase influence caused by the Fresnel zone caused by radio wave propagation by arranging a ring made of a radio wave absorber or the like in front of the transmitting/receiving antenna. This allows for smaller antennas and transceivers by selectively selecting the signal to pass through, thereby equivalently increasing the gain of the antenna, thereby reducing the transmitter output, or increasing the received level margin. achieve.

0004

2. Description of the Related Art Conventionally, various antennas such as parabolic antennas and patch-type phased array antennas have been developed as antennas used in satellite communication systems, and some of them are actually used.

[0005]

[Problems to be Solved by the Invention] However, in the above-mentioned conventional antenna, in order to improve the gain of the antenna itself, the antenna itself and the device that drives the antenna itself become larger, and the design of the antenna itself becomes larger. The problem was that it became complicated.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an antenna that can improve the gain without increasing the size of the antenna itself or the device that drives the antenna itself.

[Configuration of the invention]

[0008]

[Means for Solving the Problems] In order to achieve the above object, an antenna according to the present invention is characterized by comprising an antenna body for transmitting and receiving radio waves, and a diffraction section provided on the front surface of the antenna body. There is.

[0009]

[Operation] In the above configuration, the diffraction section diffracts the radio waves transmitted and received by the antenna body to correct the phase influence due to the Fresnel zone that occurs during radio wave propagation, or to select only radio signals passing through a specific Fresnel zone. to improve the gain of the antenna body.

0010

[Example] First, prior to a detailed explanation of the present invention, the background of the present invention will be explained.

[0011] If there is a mountain in the radio wave propagation path and visibility is difficult, a diffraction plate is installed above the mountain line and the phase of the radio wave propagation path is adjusted so that the level at the receiving point increases. There are known techniques for shielding the negative phase component (edited by the Institute of Electronics and Communication Engineers, Antenna Engineering Handbook, October 30, 1980, Ohmsha, p. 309).

[0012] The present invention applies such techniques to correct the phase influence caused by the Fresnel zone caused by radio wave propagation, and to select only radio signals that have passed through a specific Fresnel zone, thereby adjusting the gain of the receiving antenna. equivalently increases.

[0013] Hereinafter, an antenna according to the present invention to which the above-described technology is applied will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of an antenna according to the present invention.

The antenna shown in this figure is equipped with an antenna body 1 and a ring section 2. The ring section 2 corrects the phase influence due to the Fresnel zone caused by radio wave propagation, and corrects the phase influence of radio waves passing through a specific Fresnel zone. By selecting only the signal, the gain of the antenna main body 1 is equivalently increased.

In this case, the ring portion 2 is arranged on a glass 3 disposed perpendicularly to the path of the radio wave signal received by the antenna body 1, and on the glass 3 so as to form a concentric circle centered on the path. Radio wave absorber formed in (
The ring 4 is made of a material that provides attenuation of "13.7 dB" in passing absorption, and compared to the path length passing through the center of the ring 4, the distance from the inner diameter of the ring 4 to the antenna body 1 is The dimensions of the ring 4 are set so that the path length difference is "λ/2" (λ is the wavelength), and the path length difference from the outer diameter of the ring 4 to the antenna body 1 is "λ". has been done.

In such a configuration, when the frequency of the radio signal is "12 GHz" and the half width of the antenna body 1 is "30 degrees" and "16 degrees", and the gain increase due to the ring 4 is measured, as shown in FIG. As shown, the gain could be improved by more than +6 dB with the beam spreading outward from the center of the inner and outer diameters of the ring 4.

As described above, in this embodiment, the ring portion 2 is provided on the front surface of the antenna body 1 to correct the phase influence caused by the Fresnel zone caused by radio wave propagation, and to correct the phase influence caused by the Fresnel zone caused by radio wave propagation, and to Therefore, without increasing the size of the antenna body 1 itself or the device that drives the antenna body 1,
Gain can be improved.

Further, in the above-described embodiment, the ring 4 is constructed using a radio wave absorber, but by using a dielectric material instead of the radio wave absorber, the ring 4 can be constructed using a radio wave absorber.
In addition to the gain increase shown in Figure 2, the phase shift of the radio wave signal passing through the
The frequency may be increased to a Fresnel zone or a sixth touching zone, or a radio wave signal passing only through the first Fresnel zone may be received.

Further, in the above-described embodiment, the glass 3 is arranged in front of the antenna body 1 and the ring 4 is formed on the glass 3, but if the antenna body 1 is an indoor antenna or the like, , use a commercially available cover for the antenna body 1 (a cover with low passing loss) instead of the glass 3, and attach the ring 4 to this cover.
may be formed.

[0021]

As described above, according to the present invention, the gain can be improved without increasing the size of the antenna itself or the device for driving the antenna itself.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an antenna according to the present invention.

FIG. 2 is a table showing an example of gain measurement of the antenna shown in FIG. 1;

[Explanation of symbols]

1　Antenna body 2 Diffraction part (ring part) 3 Glass 4 Ring

Claims (1)

[Claims] 1. An antenna comprising: an antenna body for transmitting and receiving radio waves; and a diffraction section provided on the front surface of the antenna body.