JPS62131611A - Parabolic plane for parabolic antenna - Google Patents

Abstract

PURPOSE:To decrease heat energy of the sun ray at a focus of a parabolic face and to prevent deformation of the parabolic face itself due to high heat by providing minute ruggedness to a radio wave reflecting plane of the parabolic plane. CONSTITUTION:The ruggedness of nearly 1mum deep is processed mechanically in advance nearly without any gap to the surface of a radio wave reflecting plane 5 of the parabolic plane 1 having a pair line rubbed pattern 10 and the radio reflecting plane 5 is formed to the recessed side of the parabolic face 1. The parabolic plane 1 is fixed to a converter fitting arm 3 by a screw 4, the assembly is fixed to a support 6 by a mounting metallic fixture 7 and an elevating angle adjusting metallic fixture 8 and a converter 2 is fitted to a focus 9 of the parabolic plane 1 to constitute the parabolic antenna. Thus, the sun ray is reflected irregularly in said rugged surface and the heat energy collected to the focus 9 is reduced remarkably, then abnormal temperature rise of the converter is prevented. In this case, the size of said ruggedness is larger than 0.4mum and the depth is 1/32 of the wavelength of the received radio wave. In forming a corrosion proof and weather resistance metal-made parabolic plane by a stainless steel plate, it is not required to apply the surface treatment and corrosion proof painting to the parabolic face.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a parabolic surface of a parabolic antenna, and particularly to a parabolic surface of a parabolic antenna suitable for reducing the thermal energy of sunlight at the focal point in front of the parabolic surface. Conventional technology] The material of the parabolic surface of a conventional parabolic antenna is FR.
P resin, aluminum plates, galvanized iron plates, etc. are used, and their surfaces are either painted or subjected to oxidized surface treatment (e.g. alumite treatment) and then colored by further painting. Ta.

[Problem that the invention seeks to solve]

The above-mentioned prior art does not give consideration to the point that the parabolic surface can be used for a parabolic antenna without coloring surface treatment.

That is, the coloring treatment of the antenna surface of the conventional parabolic antenna was carried out from the viewpoint of weather resistance and corrosion resistance. However, considering the thermal deformation caused by heat absorption on the parabolic surface, it is better to paint it in a light color.

If the color is light, the reflectance of sunlight will be high, and there is a problem that the converter provided at the focal point will become hot.

Further, alumite-treated aluminum plates, FRP resins, and the like have good weather resistance and corrosion resistance, but have extremely high reflectance of sunlight and the temperature at the focal point becomes extremely high, so they have been painted. However, in this case as well, taking into account thermal deformation due to heat absorption, only light-colored paint can be applied, so the reflectance of sunlight cannot be reduced sufficiently, and the converter installed at the focal point becomes hotter. I couldn't avoid it.

Note that if the parabolic surface is thermally deformed, a portion of the received radio waves will no longer be reflected by the converter, resulting in a decrease in reception performance.

An object of the present invention is to reduce the thermal energy of sunlight at the focal point of the parabolic surface of a parabolic antenna, and to prevent the parabolic surface itself from being deformed by high heat.

[Means for solving problems]

The above object is achieved by providing minute irregularities on the radio wave reflecting surface of the parabolic surface of the parabolic antenna. For example, the unevenness of the radio wave reflecting surface is treated by surface treatment such as straight hairline or curved hairline pattern or fine blasting on the entire surface of the reflecting surface. The surface treatment is performed on the parabolic surface in a plate-like state before molding, or after molding.

Furthermore, by chemical etching or chemical polishing, the same type of uneven surface as described above can be created, and the radio wave reflecting surface of the parabolic surface can be made into an uneven surface. In addition, minute irregularities or hairline-like irregularities can also be formed on the parabolic surface using a laser beam or the like.

Another method is to transfer the uneven surface of a roll onto the plate when mechanically manufacturing the plate, thereby forming a finely uneven surface with continuous identical patterns.

[Effect]

The minute irregularities provided on the radio wave reflecting surface of the parabolic surface of the parabolic antenna diffusely reflect sunlight (including infrared rays), significantly reducing the sunlight energy concentrated at the focal point, and the radio waves remain the same as before. It can be concentrated on the focal point of the surface.

On the other hand, the depth of the unevenness of the radio wave reflecting surface is preferably 0.5 μm or more in order to diffusely reflect sunlight.

According to the description in 1.1, even without coloring the parabolic antenna, sunlight is diffusely reflected on the radio wave reflecting surface with minute irregularities, and measures against high heat at the focal point can be taken, resulting in high heat deterioration of the converter and damage to the parabolic surface. It is possible to prevent the occurrence of distortion due to heat.

In addition, if a corrosion-resistant and weather-resistant metal plate is used and the same type of minute irregularities are added to the radio wave reflecting surface of the parabolic surface, the metal plate itself is corrosion-resistant and weather-resistant, so there is no need to paint it, and the problem of high-temperature deterioration of the converter also occurs. No.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. The radio wave reflecting surface 5 of the parabolic surface 1 having a hairline uneven pattern 10 as shown in the hairline enlarged view of an embodiment of FIG. The parabolic surface of the parabolic antenna is molded and manufactured so that the radio wave reflecting surface 5 is on the concave side of the parabolic surface 1, as shown in FIG. After that, drill holes for mounting screws, fix to converter mounting arm 3 with screws 4,
It is fixed to the column 6 using the mounting bracket 7 and the elevation adjustment bracket 8,
Attaching the converter 2 to the focal point 9 of the parabolic surface 1 constitutes a parabolic antenna. FIG. 2 is a front view of the parabolic antenna with the above-mentioned hairline uneven pattern 10, and FIG. 3 is a side view showing a cross-sectional view of a part of the parabolic surface shown in FIG. 6 When a parabolic antenna made of a corrosion-resistant and weather-resistant metal plate is used as an example of the present invention, the thermal energy of sunlight sometimes changes the direction of the broadcasting satellite and the direction of the sun around the vernal and autumnal equinoxes. Sometimes they line up almost in a straight line. At this time, the converter is most likely to heat up.

Even in this case, sunlight can be diffusely reflected by the minutely uneven surface of the present invention, and heat energy can be collected at the focal point 9. Further, when the parabolic surface made of a corrosion-resistant and weather-resistant metal plate is made of a stainless steel plate, there is no need to perform surface treatment or anti-corrosion coating on the parabolic surface, and the number of steps after forming the parabolic surface can be reduced. Also, when painting a parabolic surface, it is advantageous not to paint it because some paints have the property of absorbing radio waves and may weaken the reflected radio waves. In addition to the parabolic surface, if the converter mounting arm and the like are also made of stainless steel, the parabolic antenna installed outdoors can be rust-proofed and the life of the antenna can be greatly extended. In addition to the patterns shown in Figures 4 and 5, it is also possible to create a design pattern on a monotonous metal surface by adding thin irregularities or linear hairline irregularities to the surface of a parabolic surface such as those shown in Figures 5 and 6. It is possible to create a parabolic surface for a parabolic antenna with an excellent decorative pattern by taking advantage of the metallic luster by combining the uneven surface of blasting instead of a material.

The effects of the embodiments of the present invention will be explained in numerical terms as follows.

At 11:30 a.m. on a clear day with an outside temperature of 22°C, we tested stainless steel parabolic surfaces with and without bare lines, and galvanized steel sheets with a beige pigmented coating approximately 30 μm thick (diameter = 0). , 4.8 m
) The heat-sensitive part of a thermocouple type thermometer was installed at each focal point of the sun, and the temperature was measured with the parabolic surface facing the sun, resulting in the following temperatures.

・Stainless steel plate without hairline unevenness...457
℃・Stainless steel plate hairline unevenness technique (depth 1μm)・
...184°C - Galvanized steel plate beige painted product (thickness 30μm)...
As a result of observing a temperature rise of 207°C, it was found that the hairline unevenness technique of the present invention, in which the radio wave reflecting surface is provided with a finely uneven surface, is the most effective against high heat. This makes it possible to prevent the converter from becoming too hot and, in turn, extend the life of the converter. In addition, the roughness of the metal surface of the stainless steel plate without hairline unevenness is a horizontal plane with a maximum roughness of 0.4 μm or less, as shown in FIG. 8, and the surface roughness curve 11 has many smooth parts.
It becomes. On the other hand, the surface roughness of the metal surface obtained by processing a stainless steel plate with the hairline uneven pattern shown in Fig. 4 to a depth of 1 μm without any gaps is that the surface roughness curve 11 shown in Fig. 7 is an inclined surface, and the surface roughness is smooth. It can be seen that there are very few parts. From the above, it can be seen that making the surface roughness of the parabolic surface larger than 0.4 μm is effective in countering the high heat of the converter.

However, care must be taken to keep the surface roughness to a level that does not significantly affect radio wave reception performance. The radio wave reception performance given by the surface roughness is determined by the following formula.

D: Antenna aperture diameter (m) λ: Free space wavelength (m) η: Antenna aperture efficiency Lf: Feeding system loss ε: Mirror accuracy G: Antenna gain Calculate the receiving performance (antenna gain G) using the above formula. Figure 9 was drawn using this method.

The conditions are the following numerical values of the above-mentioned embodiments of the present invention.

D: 0.48m λ: 0.025m Lf=1. ○ η: 1.0 As is clear from FIG. 9, the surface roughness □ of the receiving performance (anti-λ gain G) can be maintained at 98.1%, and it can be seen that the deterioration of the receiving performance is small.

Therefore, in order to satisfy both the diffused reflection of sunlight and the radio wave receiving performance, it is preferable that the radio wave reflecting surface has a diameter of more than 0.4 μmλ and less than or equal to □.

〔Effect of the invention〕

According to the present invention, sunlight incident on the parabolic surface is diffusely reflected by the micro-rough surface, so it is not concentrated on the focal point of the parabolic surface, preventing high heat deterioration of the converter, and also preventing distortion of the parabolic surface due to heat. can. It goes without saying that if a coloring treatment is applied in addition to the present invention, the converter will be more effectively prevented from being degraded by high heat.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of only a partially enlarged section of the parabolic surface in FIG. 3, FIG. 2 is a front view of a parabolic antenna showing an embodiment of the present invention, and FIG. 3 is a parabolic surface in FIG. 1. 4 is an enlarged partial view of the surface showing an embodiment in which the surface of the radio wave reflecting surface is patterned with minute linear unevenness, and FIG. 5 is a cross-sectional side view. FIG. 6 is a partial view of the surface showing an example of the parallel linear hairline uneven pattern. Figure 7 shows the surface roughness of the stainless steel plate after hairline roughening, Figure 8 shows the surface roughness of the stainless steel plate before hairline roughening, and Figure 9 shows the relationship between the surface roughness of the parabolic surface and the antenna gain. FIG. DESCRIPTION OF SYMBOLS 1... Parabolic surface, 2... Converter, 3... Converter mounting arm, 4... Screw, 5... Radio wave reflective surface, 6... Support column, 7... Mounting bracket, 8... ...Elevation angle adjustment fitting, 9...Focal point, 10...Hairline uneven pattern, 11...Surface roughness curve.

Claims (1)

[Claims] 1. A parabolic surface of a parabolic antenna, characterized in that the parabolic surface of the parabolic antenna is provided with minute irregularities on a radio wave reflecting surface. 2. The parabolic surface of the parabolic antenna according to claim 1, wherein the minute irregularities are larger than 0.4 μm and have a depth dimension of 1/32 of the wavelength of the received radio wave or less. 3. The parabolic surface of the parabolic antenna according to claim 1, wherein the minute irregularities are linear hairline irregularities or curved hairline irregularities. 4. The parabolic surface of the parabolic antenna according to claim 1, wherein the minute irregularities are a surface processed by blasting or liquid honing. 5. The parabolic surface of the parabolic antenna according to claim 1, wherein the minute unevenness is a surface processed by chemical etching, electrolytic polishing, or chemical polishing.