JPH0915327A - Assembling method of antenna equipment - Google Patents

Abstract

PURPOSE: To realize attainment of high precision and facilitation of assembly including regulation of a geometrical relationship between a primary radiator and a reflector, regarding an antenna comprising the primary radiator and the reflector. CONSTITUTION: An optical reflector Ro having the same curved surface as the central part of a reflector R is disposed in this central part, and in front of the reflector R, a transparent plate G is so disposed as to intersect the optical axis of this reflector perpendicularly. A light beam is radiated from the central part of a primary radiator (r) toward the optical reflector Ro and the relative positional relationship between the primary radiator (r) and the reflector R is regulated so that light spots S1 and S2 on the optical reflector Ro viewed through the transparent plate G be kept in a prescribed positional relationship.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of assembling an antenna device used for a Doppler soder or the like.

[0002]

2. Description of the Related Art A Doppler soder for wind speed measurement has been developed for the purpose of collecting data of wind direction and speed in the sky necessary for taking measures against air pollution such as smog. This wind speed measurement Doppler soder radiates sound waves and radio waves to the atmosphere above, and fluctuations in the composition of the atmosphere due to differences in the content ratio of water vapor and pollutants, and fluctuations in density due to temperature differences, etc. It receives weak reflected waves generated at discontinuous points in acoustic and electrical characteristics. Then, from the amount of Doppler shift of the frequency included in the received reflected wave, the moving speed of the discontinuous portion where the reflected wave is generated, that is, the wind speed / direction of the portion is measured.

In the above Doppler soder for measuring wind speed,
A horn reflector antenna is widely used as an antenna device. This horn reflector / antenna emits and receives sound waves, and as shown in a sectional view in FIG. 3, a rotary parabolic reflector R forming a peripheral portion of a virtual paraboloid of revolution, and the virtual parabolic reflector R. It is composed of a horn-shaped primary radiator r arranged at the focal position of the paraboloid of revolution corresponding to the paraboloidal reflector R. The shape of the horn may be a cone, a pyramid, a polygon, etc.
A conical horn is used, as shown in.

The sound wave radiated from the electroacoustic conversion element AT installed at the root side of the horn-shaped primary radiator r becomes a spherical sound wave, and a rotating parabolic reflector from the tip of the primary radiator r. It is radiated toward R, is reflected by this reflecting mirror, becomes a plane wave, and is radiated right above. A part of the reflected wave generated above the horn reflector / antenna is received by the electroacoustic conversion element AT by following a path opposite to that at the time of radiation. In a horn reflector antenna that emits radio waves instead of sound waves, a feeding waveguide is installed instead of the electroacoustic conversion element AT.

The rotating parabolic reflector R and the primary radiator r are installed in a resin casing C held on a base D so as to maintain a certain geometric relationship. That is, based on the calculation result, the reflecting mirror R is so arranged that the sound wave reflected by the paraboloidal reflector R propagates in a predetermined direction that makes an angle with the optical axis of the reflecting mirror R, for example, in the direction of this optical axis. And the geometrical relationship between the primary radiator R (distances d1 and d2, angle θ in FIG. 2)
Etc.) is set.

[0006]

In the above-mentioned conventional horn reflector antenna, the geometrical relationship between the rotating parabolic reflector R and the primary radiator r is set based on the calculation result. The effect of error is not taken into consideration. However, in reality, various errors that are difficult to measure, such as manufacturing errors of the rotary parabolic reflector R and mounting errors on the housing C, are included, so that the sound wave emission direction deviates from the set direction. However, there is a problem that an error occurs in the measurement result of the wind speed and the wind direction by the Doppler soder.

[0007]

According to the antenna assembling method of the present invention, an optical reflecting mirror having the same curved surface as that of the central portion is arranged in the central portion of the reflecting mirror, and the light is reflected in front of the reflecting mirror. A transparent plate is arranged orthogonal to the axis, and a laser beam is emitted from the central part of the primary radiator so that the light spot on the optical reflecting mirror seen through the transparent plate maintains a constant positional relationship. It is configured to adjust the relative positional relationship between the radiator and the reflecting mirror.

[0008]

[Function] For sound waves, radio waves, and light, by utilizing straightness and regular reflection that the incident angle and the reflection angle are equal,
The operating principle is common in that the primary radiator and the reflecting mirror are combined to radiate each in a desired direction. Unlike light, sound waves and radio waves cannot be visually inspected for their propagation paths, so it is extremely difficult to confirm whether or not they are emitted in a desired direction. In that respect, the path of the light can be easily confirmed visually. Therefore, the geometrical relationship between the primary radiator and the reflecting mirror can be easily adjusted by using light instead of sound waves or radio waves during assembly.

[0009]

1 is a sectional view showing the structure of a horn reflector / antenna to which an antenna assembling method according to an embodiment of the present invention is applied together with various instruments used for assembling, and FIG. 2 is a plan view. is there. 1 and 2, R is a rotating parabolic reflector, r is a primary radiator, C is a housing made of resin,
D is a holder for holding the housing C, E is an elastic spacer, and h is a screw. Further, P is a thick insulator, LD is a laser diode, and G is plate glass.

A rotating parabolic reflector R is installed on the bottom of a resin casing C. The horn-shaped primary radiator r
While the opening is positioned at the focal point of the paraboloid of revolution, the casing C
Is attached to the side of. A frustoconical insulating substrate P holding the laser diode LD in the center is fitted into the opening of the primary radiator r. An optical reflecting mirror Ro, which is made of a flexible thin small foil piece such as silver paper, is adhesively fixed to the central portion of the reflecting mirror R. A plate glass G is placed on the opening surface B of the housing C.

A direct current is supplied to a laser diode LD mounted on the center of the substrate P via a lead wire (not shown) to cause it to emit laser light. The laser beam generated by the laser diode LD is emitted so as to pass through the central axis of the primary radiator r. This laser beam
It is regularly reflected by an optical reflecting mirror Po which is fixedly adhered to the central portion of the rotating parabolic reflecting mirror R, and is a glass plate G as a light ray L1.
Incident on. A part of the light ray L1 incident on the plate glass G is transmitted through and emitted upward, and the remaining part L2 is normally reflected by the plate glass G and again incident on the reflecting mirror Ro, and is normally reflected by the reflecting mirror Ro. It receives the reflection and propagates toward the laser diode LD. In addition to the above-mentioned regular reflection, diffuse reflection also occurs at the reflecting mirror Ro, and a part of the laser beam that has been diffusely reflected by the reflecting mirror Ro follows a path opposite to the laser beam L2, passes through the plate glass G, and is emitted right above.

A small reflecting mirror Ro fixed to the central portion of the rotating parabolic reflecting mirror R is observed from above the plate glass G through it. First, the laser beam L1 is regularly reflected by the reflecting mirror Ro, passes through the plate glass G, and is emitted upward.
Is observed as a light spot S1 on the reflecting mirror Ro. On the other hand, the laser beam which is reflected by the plate glass G and again enters the reflecting mirror Ro as the light beam L2, receives the diffuse reflection by this, and follows the propagation path opposite to the light beam L2, and passes through the plate glass G. Is observed as the light spot S2.

Here, when the positions of the light spots S1 and S2 coincide with each other, the propagation path of the laser beam L1 which is incident on the plate glass G from below and the reflected beam L by the plate glass G.
It is nothing but the state in which the two propagation paths match. In this state, the laser beam L1 is vertically incident on the plate glass G, and thus on the opening surface B of the housing C. In this case, if a level is installed on the plate glass G and the plate glass G is kept horizontal, the laser beam L1 propagates in the vertical direction.

As described above, in order to adjust the positional relationship between the light spots S1 and S2, the fixing position and the fixing angle of the primary radiator r are adjusted through the elastic spacer E with respect to the housing C. When the setting of the relationship between the position and angle of the rotary parabolic reflector R and the primary radiator r is completed through such adjustment,
The substrate P on which the laser diode LD is mounted is removed from the tip surface of the primary radiator R, and the plate glass G is removed from the opening surface B of the housing C.

The case where the sound waves are emitted in the direction of the normal to the opening surface of the housing by arranging the light points S1 and S2 to coincide with each other has been described above. However, in general, by setting the two-dimensional positional relationship between the light spots S1 and S2 in an appropriate state, the sound wave is tilted at a desired angle with respect to the normal line of the opening surface of the housing. It can also be configured to emit in the direction of. That is, assuming that the opening surface B exists in a horizontal plane, the distance between the light points S1 and S2 is d, and the distance between the center of the opening surface B of the housing C and the central portion of the rotating parabolic reflector R is D. Then, the angle θ formed by the emission direction of sound waves or radio waves and the vertical direction is θ = d / (2D).

Further, the case where a laser diode is used as a light source has been illustrated. However, it is also possible to use a photodiode, an incandescent lamp, or the like as a light source alone or in combination with a converging mechanism including a lens. When a laser diode is used, in order to protect the eyes of the operator, the laser diode is intermittently operated at a longer cycle to reduce the emitted light power or to color the plate glass G. Therefore, safety measures such as attenuating transmitted light are taken.

Further, the case where the present invention is applied to a horn reflector antenna is illustrated. However, the invention can be applied to other similar antennas such as offset parabolic antennas.

Furthermore, the case where the present invention is applied to a Doppler soder that transmits and receives sound waves has been illustrated. However, the present invention can also be applied to a Doppler radar that transmits and receives radio waves.

[0019]

As described above in detail, since the antenna assembling method according to the present invention uses light instead of sound waves or radio waves during assembly, the geometry of the primary radiator and the reflector is It can be easily adjusted while visually checking the physical relationship. Therefore, the desired radiation direction of the sound wave or the radio wave from the antenna can be set accurately, and the measurement accuracy of the Doppler soda or the like can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a horn reflector / antenna to which an antenna assembling method according to an embodiment of the present invention is applied together with various devices used for assembling.

FIG. 2 is a plan view showing the configuration of the horn reflector / antenna together with various devices used for assembly.

FIG. 3 is a sectional view showing a configuration of a horn reflector antenna to which an antenna assembling method according to an embodiment of the present invention is applied.

[Explanation of symbols]

 R Rotating parabolic reflector r Horn-shaped primary radiator Ro Optical reflector AT Electroacoustic transducer LD Laser diode C Housing B Housing aperture G Plate glass L1, L2 Laser beam S1, S2 Light spot

Claims (2)

[Claims] 1. An antenna device comprising a primary radiator that emits a sound wave or a radio wave and a reflecting mirror that reflects the sound wave or the radio wave emitted from the primary radiator, wherein the central portion of the reflecting mirror is the central portion. An optical reflecting mirror having the same curved surface as the above, a transparent plate is placed in front of the reflecting mirror so as to be orthogonal to its optical axis, and from the central portion of the primary radiator toward the optical reflecting mirror. The relative positional relationship between the primary radiator and the optical reflecting mirror is adjusted so that a light beam is emitted and the light spot on the optical reflecting mirror seen through the transparent plate maintains a constant positional relationship. A method for assembling an antenna device, comprising: 2. The method for assembling an antenna device according to claim 1, wherein the light beam is a laser beam.