JP3250815B2 - Rotating scanning antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary scanning type antenna device used for a radar device and the like, and more particularly to a polarization changing type of a radiated radio wave according to a use environment such as weather. The present invention relates to a rotary scanning type antenna device having a diversity function.

[0002]

2. Description of the Related Art Conventionally, there has been known a rotary scanning type antenna device for rotatingly scanning a radio wave beam by reflecting a radio wave beam radiated from a radiator by a rotary reflector (Japanese Patent Publication No. 32-8971). . In addition, a technique is known in which a beam is scanned while converting a linearly polarized wave into a circularly polarized wave by forming a grooved plate or a grid on the reflection surface of such a rotary reflector (Japanese Patent Laid-Open No. Hei 2 (1990) -1990). 21930
No. 5 publication). Further, there is also known a configuration in which a reflection surface of such a rotating reflector is curved to converge a reflected beam (Japanese Patent Publication No. 51-20799, etc.).

[0003] In general, the typical polarization state of a radio wave beam is circular polarization or linear polarization. Which of the polarization waves is more advantageous to use as a radar device or the like is as follows.
It changes depending on the weather such as rainy weather or fine weather. Conventionally, there has been a polarization diversity scheme in which a rotary scanning antenna apparatus using a circularly polarized radio beam and a rotary scanning antenna apparatus using a linearly polarized radio beam are installed, and the received powers of both are combined. It is used.

[0004]

In the above-mentioned conventional rotation scanning apparatus of the polarization diversity system, two systems must be provided: a circular polarization apparatus and a linear polarization apparatus. Therefore, there is a problem that not only is the configuration of the entire system complicated and expensive, but also the installation space is increased. Accordingly, it is an object of the present invention to provide a polarization-diversity rotary-scanning antenna apparatus which has a simple configuration, is inexpensive, and does not cover installation space.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, a rotary scanning type antenna apparatus according to the present invention comprises a radiator for radiating a radio wave beam, and a radiator for reflecting the radiated radio wave beam to generate a radio wave beam. A first reflector and a second reflector which are arranged close to each other to change the propagation direction, one of the reflecting surfaces having a structure for maintaining the polarization state of the reflected wave, and the other reflecting surface being a reflected wave A rotating scanning mechanism that rotates the first and second reflectors to rotate and scan the reflected waves by rotating the first and second reflectors, Means are provided for selectively functioning only one of them according to the usage environment such as weather.

That is, according to the rotary scanning type antenna device of the present invention, the first and second reflectors are arranged close to each other, and means for selectively functioning only one of them in accordance with the weather or the like is provided. This provides a device of this type that has a simple configuration, is inexpensive, and does not cover an installation space.

[0007]

According to a preferred embodiment of the present invention, the first and second reflectors have a rotation set substantially parallel to a propagation direction of a radio wave beam emitted from the radiator. By being rotated around the axis, it is configured to reduce the occupied space.

According to a further preferred embodiment of the present invention,
The first and second reflectors are arranged so as to have different heights from each other, so that they do not shield the reflected waves from each other.

[0009]

FIG. 1 is a front view showing the configuration of a rotary scanning antenna device according to an embodiment of the present invention. This rotary scanning type antenna device includes transmission / reception ports 1A and 1B of the electromagnetic horn, reflection plates 4A and 4B, rotation shafts 6A and 6B, variable angle drive units 9A and 9B, and the like.

It is composed of a circular tapered electromagnetic horn whose diameter increases toward the tips of the transmitting and receiving ports 1A and IB, and is installed almost vertically. Circularly polarized radio waves in an appropriate frequency band are selectively supplied from a transceiver (not shown) to one of the transmitting and receiving ports 1A and 1B via a circular waveguide 1C and a rotary waveguide switch 1D. Radiated vertically upward. Transceiver 1A,
Directly above 1B, reflectors 4A and 4B are arranged at an angle of approximately 45 ° with respect to the vertical direction, and the reflected waves generated at the respective reflecting surfaces are propagated in a substantially horizontal direction.

A half-wave plate is formed on the reflecting surface of the reflector 4A. That is, a plurality of fins are arranged in parallel on the reflecting surface of the reflector 4A with an interval of less than half a wavelength, and the circularly polarized radio wave radiated from the transmitting / receiving port 4A is converted into a linearly polarized radio wave. Reflect while converting. A flat surface is formed on the reflecting surface of the other reflector 4B, and the circularly polarized radio wave radiated from the transmitting / receiving port 4B is reflected as it is as a circularly polarized radio wave.

The reflecting plates 4A, 4B are provided with
A is attached to the rotating shafts 6A and 6B via A and 9B. The rotating shafts 6A and 6B are set substantially parallel to the propagation direction of the radio waves radiated from the transmitting / receiving ports 1A and 1B, and are rotated around their respective central axes by a rotating device (not shown). The reflection plates 4A and 4B are rotated by the rotation of the rotation shafts 6A and 6B, and the reflected waves are rotationally scanned over the entire 360 ° in the horizontal plane.

The reflectors 4A and 4B are mounted at different heights. Therefore, the reflection plate 4
A radio wave rotationally scanned by A is not shielded by the reflector 4B, and similarly, a radio wave rotationally scanned by the reflector 4B is not shielded by the reflector 4A. The difference between the heights of the two reflectors is negligible compared to the extent of the space in which the reflected wave is scanned.

Which of the reflection plates 4A and 4B, that is, which of the circularly-polarized radio wave and the linearly-polarized radio wave is used for the rotational scanning is determined according to the weather, the topography and the like.
For example, in rainy weather, a radio wave is radiated from the transmitting / receiving port 1A by operating the rotary waveguide switch 1D, and rotational scanning is performed using the reflected radio wave converted into linearly polarized wave by the reflector 4A. . In fine weather, by rotating the rotary waveguide switch 1D in reverse, radio waves are emitted from the transmission / reception port 1B, and rotational scanning is performed using radio waves reflected circularly by the reflector 4B.

As described above, two transmitting / receiving ports 1A and 1B are provided so as to face the reflecting plates 4A and 4B, respectively.
By using a rotary waveguide switch installed in the middle of the feed path to supply radio waves to one of the transmitting and receiving ports, only one transmitting and receiving port is installed and this is used for each reflection. As compared with a configuration in which the reflection plate is moved so as to face one of the plates, it is possible to switch the used reflection plate while keeping the fluctuation of the electric characteristics to a minimum.

Although the configuration using a flat reflecting plate has been described above, the present invention can be applied to a case where a reflecting surface having a curved reflecting surface is used.

[0017]

As described above in detail, in the rotary scanning type antenna device of the present invention, the first and second reflectors are arranged close to each other, and only one of them is selectively used according to the weather or the like. Since such a configuration is provided with a means for functioning, the configuration of this type of apparatus is simple and inexpensive, and the installation space is not reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing the configuration of a rotary scanning antenna device according to an embodiment of the present invention.

[Explanation of symbols]

 1A, 1B Transmit / receive port 1C Waveguide 1D Rotary waveguide switch 4A, 4B Reflector 6A, 6B Rotary axis 9A, 9B Variable angle drive

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01Q 3/00-3/46 H01Q 21/00-21/30 H01Q 23/00 H01Q 25/00-25/04

Claims (2)

(57) [Claims] 1. Two radiators for radiating a radio wave beam, and reflecting the radiated radio beam to generate a radio wave beam.
Each of the two radiators to change the direction of propagation
First and second arranged opposite to each other and close to each other
A reflector, one reflecting surface of which reflects the state of polarization of the reflected wave.
And the other reflective surface is polarized
And a structure in which the first and second reflectors are rotated so that the
Only one of the first and second reflectors is used for rotating and scanning the radiation,
Means for selectively functioning according to the use environment , wherein the first and second reflectors are arranged at different heights from each other.
Radio beam emitted from the radiator
Around a rotation axis installed almost parallel to the propagation direction of
Rotary scanning antenna device characterized by being rolled up
Place. 2. The radiator according to claim 1 , wherein said first and second reflectors are radiated from said radiator.
Reflect the radio beam and change its propagation direction by almost 90 °
A rotary scanning antenna device.