JPH08125416A - Offset antenna with snow melting device - Google Patents

Abstract

PURPOSE: To prevent and reduce deposited snow onto a reflecting mirror by mounting one or plural far-infrared ray generating means to a lower side of the reflecting mirror to the reflecting mirror at the primary radiator side and at the outside of a propagation path of a radio wave from a focus via the reflecting mirror. CONSTITUTION: A far infrared ray generating means 11 is arranged to an offset reflecting mirror 2 at primary radiator 2 side and at the outside of a propagation path 5 of a radio wave from a focus via the offset reflecting mirror 1. The far infrared ray generating means 11 is made up of a far infrared ray generating source 27 consisting of an 8-shaped sheath heater and a semi-spherical or parabolic plane of rotation shaped reflecting plate and a far infrared ray holder 22 holding the source 27. Snow deposition is eminent at the lower part of the offset reflecting mirror 1 and the upper part of the primary radiator 2, and the far infrared ray generating source 27 emits a required part with much snow deposition with the configuration above. Thus, the power consumption is far less in comparison with the case with heating the entire offset reflecting mirror 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture antenna mainly used for microwave communication or radar, and more particularly to prevention of snow accretion of an offset antenna for satellite communication earth station.

[0002]

2. Description of the Related Art FIG. 9 (a) is a front view of a conventional offset antenna, and FIG. 9 (b) is a side view. In the figure, 1 is an offset reflecting mirror, and 2 is a primary radiator of a conical horn, for example. The center of the radio wave phase of the primary radiator 2 coincides with the focal point of the reflecting mirror 1. 3 is a frame for coupling the offset reflecting mirror 1 and the primary radiator 2; 4 is a frame for coupling the reflecting mirror 1 and the primary radiator 2; 5 is a transmission path for receiving or transmitting radio waves;
6 is an outer peripheral ring that reinforces the periphery of the reflecting mirror 1, 7 is a skeleton that holds the reflecting mirror 1, 8 is an AZ (azimuth) adjusting mechanism that determines the direction of the received or transmitted radio wave in the horizontal plane, and 9 is the received or transmitted radio wave. An EL (elevation) adjustment mechanism that determines the direction in the vertical plane, 10 is the offset reflecting mirror 1 in the building,
It is a pillar for installing on a steel tower.

The conventional offset antenna is constructed as described above, and when it is considered as a receiving antenna for a satellite communication earth station, radio waves coming from an artificial satellite (not shown) pass through the transmission path 5 and the reflecting mirror 1. It is reflected by and is focused on the radio wave phase center of the primary radiator 2 and reaches a receiver (not shown).
The offset parabolic antenna does not have side lobe deterioration and gain reduction due to blocking as compared to a parabolic antenna or a Cassegrain antenna in which there is essentially no blocking of the transmission line 5 and there is blocking, and satellite communications and high-density antennas have good characteristics. It is used for communication.

Since the antenna is installed outdoors, in order to reduce the deterioration of cross-polarization characteristics and the decrease of gain due to snowfall in winter, the reflecting mirror 1 stands up at an angle close to vertical in the use state and the amount of snow landing is reduced. The shape of 1 is selected.

[0005]

The conventional offset antenna has a much smaller amount of snowfall than a parabolic antenna or a Cassegrain antenna that snows almost all over, and has less influence on a communication line. However, in rare cases, the communication line of the offset antenna may be lost. As shown in FIG. 10, the snow on the reflecting mirror 1 tends to snow in the lower half of the reflecting mirror 1, that is, in the range A where the angle of the plane in contact with the reflecting mirror 1 does not reach the vertical direction. This snow accretion grows from below at an angle from the vertical, and the upper part B of the primary radiator 2
This occurs because the snow that has fallen on the ground grows, blocks the opening of the primary radiator 2 and reduces the gain and changes the polarization plane. It is impossible to eliminate snow accretion in order to prevent interruption of the communication line and ensure the operation rate, no matter how the angle of the reflector 1 is set, because of the influence of snow quality and wind direction. A method of coating snow on the reflecting mirror 1 with snow or fluorinated snow, or crawling a heating wire on the back surface of the reflecting mirror 1 to melt the snow is used. However, the snow-adhesive paint has been effective for about two years at present and needs to be repainted regularly, and the method of mounting the heating wire on the back surface of the reflecting mirror 1 is the thermal reflecting mirror 1.
Is a great heat sink, it requires enormous electric power to effectively heat the reflecting mirror 1, and the diameter of the reflecting mirror is 7
If the size is as small as 5 cm or 100 cm, the cost of installing heating wires, heat insulation, and heat insulation will be much higher than the cost of the reflector. These eventually lead to increased maintenance costs,
It was difficult to improve the communication line utilization rate.

The present invention has been made in order to solve the above problems, and it substantially prevents the influence of the above-mentioned snow accretion and has a high communication line operating rate.
In particular, the objective is to obtain at low cost an offset antenna for satellite communication earth stations, which has a small reflector diameter and is dedicated to reception.

[0007]

In the offset antenna with a snow melting device of the present invention, one or a plurality of far infrared ray generating means is provided on the primary radiator side of the reflecting mirror and below the reflecting mirror from the focal point through the reflecting mirror. It is mounted on the outside of the transmission path of the radio wave.

Further, in the offset antenna with a snow melting device of the present invention, a cylindrical heater is arranged around the primary radiator with a gap, and the cylindrical heater is focused behind the opening of the primary radiator. It is mounted on the outside of the transmission path of the radio wave from the reflector.

The offset antenna with a snow melting device according to the present invention comprises one or a plurality of far infrared ray generating means on the primary radiator side of the reflecting mirror and on the lower side of the reflecting mirror of a radio wave transmission path from the focus to the reflecting mirror. It is mounted on the outside, and a cylindrical heater is arranged with a gap around the primary radiator, and this cylindrical heater is located behind the opening of the primary radiator, and the radio wave from the focal point passes through the reflector. It is mounted on the outside of the transmission line.

Further, the offset antenna with a snow melting device of the present invention comprises one or a plurality of 8-shaped sheathed heaters and a paraboloid of revolution or a hemisphere on the primary radiator side of the reflecting mirror and below the reflecting mirror. The far-infrared ray generating means composed of the reflector plate is attached to the outside of the transmission path of the radio wave from the focus to the reflecting mirror, and a cylindrical heater is arranged with a gap around the primary radiator. A cylindrical heater is mounted on the rear side of the opening of the primary radiator and outside the transmission path of radio waves from the focus to the reflecting mirror.

The offset antenna with a snow melting device according to the present invention is provided with a far infrared ray generating means composed of a rod-shaped sheathed heater and a columnar parabolic reflector on the primary radiator side of the reflector below the reflector. It is attached to the outside of the transmission path of radio waves that pass through the reflector, and a cylindrical heater is arranged with a gap around the primary radiator, and this cylindrical heater is located behind the opening of the primary radiator. , Is attached to the outside of the transmission path of radio waves from the focal point through the reflector.

[0012]

According to the present invention, by supplying electric power to the far infrared ray generating means, the required portion of the reflecting mirror is heated intensively.

Further, according to the present invention, by supplying electric power to the cylindrical heater, the cover of the cylindrical heater is heated and the vicinity of the opening surface of the primary radiator is also warmed.

According to the present invention, by supplying electric power to the far infrared ray generating means, the required portion of the reflecting mirror is heated intensively,
By supplying electric power to the cylindrical heater, the cover of the cylindrical heater is heated and the vicinity of the opening surface of the primary radiator is also warmed.

Further, according to the present invention, by supplying electric power to the 8-shaped sheathed heater, the required portion of the reflecting mirror is heated intensively, and electric power is supplied to the cylindrical heater.
While heating the cover of the cylindrical heater, the vicinity of the opening surface of the primary radiator is also warmed.

According to the present invention, by supplying electric power to the rod-shaped sheathed heater, the required portion of the reflecting mirror is intensively heated,
By supplying electric power to the cylindrical heater, the cover of the cylindrical heater is heated and the vicinity of the opening surface of the primary radiator is also warmed.

[0017]

【Example】

Example 1. 1 (a) is a front view showing a first embodiment of the present invention, FIG. 1 (b) is a side view, and FIG. 2 is a far infrared ray generating means 27.
FIG. 3 is a detailed view of a cylindrical heater having a gap around the primary radiator, and FIG. 4 is a detailed view of a cylindrical heater in close contact with the primary radiator. 9,
This is exactly the same as the conventional device shown in FIG. 1
Reference numeral 1 is a far infrared ray generating means located outside the transmission path 5 of the radio wave from the focal point through the reflecting mirror. The far infrared ray generating means is composed of a figure-shaped sheathed heater 23 and a rotary parabolic or hemispherical reflector 24. The infrared source 27 and the far-infrared holder 22 that holds the infrared source 27 are included. Figure-shaped sheathed heater 23
a is a circular parabolic or hemispherical reflection plate 24 provided behind the 8-shaped sheathed heater 23a so that a uniform irradiation amount can be obtained. Thus, it is possible to effectively irradiate the elliptical irradiation surface. Further, the far-infrared ray generating portion can be made longer than the rod-shaped sheathed heater with the same area within the rotary parabolic or hemispherical reflection plate 24, and a higher radiation amount than that of the rod-shaped sheathed heater can be obtained. Further, the far-infrared ray generating means 11 can change the far-infrared ray irradiation direction up and down by loosening the screw 12, and has a structure in which the far-infrared ray irradiation direction can be rotated in a horizontal plane by loosening the screw 13. Reference numeral 14 is a temperature measuring means such as a platinum resistance temperature detector or a thermostat, and 15 is a control section for supplying electric power to the far infrared ray generation source 27 by the output of the temperature measuring means 14. 16 is a power cable for supplying power to the far infrared ray generation source 27
Reference numeral 7 is a support rod for supporting the far infrared ray generating means 11, and a screw 18
It is fixed to the adapter 19 by this, and has a structure that can be expanded and contracted in the horizontal direction by loosening the screw 18. Reference numeral 20 denotes an adapter fixing metal fitting, which is fixed to the column 10 with a screw 21. By loosening the screw 21, the pillar 10 can be moved up and down, and the adapter 19 can rotate in a horizontal plane. Reference numeral 23b denotes a cylindrical heater provided with a gap L around the primary radiator 2 and arranged behind the opening G of the primary radiator 2, and is constituted by, for example, nichrome wire 25 insulatingly coated with silicone rubber 26. . Reference numeral 28 denotes a metallic cover which is fixed to the frame 3 by fixing the cylindrical heater 23 by adhesion or the like.

In the offset antenna with a snow melting device configured as described above, the behavior of the received wave and the transmitted wave is exactly the same as the conventional one. During snowfall, as already explained, the snow accretion state is remarkable in the lower part of the reflecting mirror 1 and the upper part of the primary radiator 2. The far-infrared ray generation source 27 can irradiate a necessary portion indicated by hatching in the lower half of the reflecting mirror 1 and its power consumption is far higher than that of heating the entire reflecting mirror 1. It is low in cost and does not require regular maintenance like snow-hardening paint, so the cost-effectiveness is particularly excellent. FIG. 5A shows a desired irradiation density, and the distance between the reflecting mirror 1 and the far-infrared ray generating source 27 is about 200 with a constant radiation amount.
In case of mm, about 1/3 below the reflector 1 is 410 W / m
² , 330W / from about 1/2 to about 1/3 below the reflector 1.
The experimental result of m ² was obtained. FIG. 5B shows a cross section D of the reflecting mirror 1.
5C shows the surface temperature distribution of D, and FIG. 5C shows the surface temperature distribution of the cross section EE of the reflecting mirror 1. 5 (b) and FIG.
As can be seen from (c), it can be seen that the surface temperature of the reflecting mirror 1 changes gently to prevent thermal deformation of the reflecting mirror 1.

In order to prevent snow from accumulating in the opening of the primary radiator 2, there is one in which a cylindrical heater 23b is attached in close contact with the primary radiator 2 to heat the opening surface by heat conduction. A dielectric material, for example, a fidome having a low thermal conductivity, such as Teflon, is inserted in this. On the other hand, the primary radiator 2
The main body of is a metal with high thermal conductivity, and the heat of the heater is not easily transmitted to the fidome, and a large amount of electric power is required to escape to the other side. Further, since the primary radiator 2 is completely brought into close contact with the primary radiator 2, it is expensive to mold the shape of the primary radiator 2 with silicone rubber. On the other hand, FIG.
As shown in FIG. 2, the cylindrical radiator 23b is attached with a gap L of 5 to 10 mm around the primary radiator 2 to heat the cylindrical heater cover with low power to heat the primary radiator 2
It is possible to prevent snow from accumulating on the upper part of the sheet to prevent the snow from growing, and to prevent the opening surface from being blocked. The cylindrical heater 23b also warms the vicinity of the opening surface to prevent snow from accumulating on the opening surface. FIG. 6 is a view showing a state of the field test. Snow is slightly present on the upper side F of the reflecting mirror 1, but it is slight, and there is no decrease in gain or deterioration of cross polarization characteristics.

Example 2. FIG. 7 (a) is a front view showing Embodiment 2 of the present invention, and FIG. 7 (b) is a side view, in which the portion under the reflecting mirror where snow melting is necessary is narrow, such as the aperture of the reflecting mirror is 75 cm. The radiation density is about 1/3 below the reflector 1 at 410
W / m ² , 33 under the mirror 1 from about 1/2 to about 1/3
One far-infrared ray generating means is attached so as to obtain 0 W / m ² .

The offset antenna with a snow melting device configured as described above can achieve efficient power consumption due to the size of the aperture of the reflecting mirror.

Example 3. 8 (a) is a front view showing a third embodiment of the present invention, and FIG. 8 (b) is a side view. Reference numeral 30 is a far infrared ray generating means, which is a rod-shaped sheathed heater 31 and a columnar parabolic reflector 32. The far-infrared ray generating source 33 and the far-infrared ray holder 34 that holds the far-infrared ray generating source 33 have a radiation density of about ⅓ below the reflecting mirror 1 of 410 W / m ² , and about ½ below the reflecting mirror 1. Up to about 1/3, it is mounted so that the power becomes 330 W / m ² .

The offset antenna with a snow melting device configured as described above has the same effect as that of the first embodiment. Further, the rod-shaped sheathed heater has an advantage that it can be easily processed.

[0024]

As described above, the present invention has a simple structure in which the far infrared ray generating means is added to the optimum position under the reflecting mirror of the offset antenna to prevent and reduce the snow accretion of the reflecting mirror, and to improve the communication line. There is an effect that an offset antenna with a snow melting device having a high operating rate can be realized at low cost.

Further, the present invention has a simple structure in which a cylindrical heater is added around the primary radiator of the offset antenna to prevent snow accretion on the opening of the primary radiator, and a snow melting device having a high communication line operating rate. There is an effect that the offset antenna with an antenna can be realized at low cost.

The present invention has a simple structure in which far infrared ray generating means is added at an optimum position below the reflecting mirror of the offset antenna and a cylindrical heater is added around the primary radiator. There is an effect that snow accretion on the opening surface of the device can be prevented and reduced, and an offset antenna with a snow melting device having a high communication line operating rate can be realized at low cost.

The present invention has a simple structure in which an 8-shaped sheathed heater is added at the optimum position under the reflector of the offset antenna and a cylindrical heater is added around the primary radiator. It is possible to prevent and reduce snow accretion on the openings of the mirror and the primary radiator, and it is possible to inexpensively realize an offset antenna with a snow melting device having a high communication line operating rate.

The present invention has a simple structure in which a rod-shaped sheathed heater is added at an optimum position below the reflecting mirror of the offset antenna and a cylindrical heater is added around the primary radiator. There is an effect that snow accretion on the opening surface of the device can be prevented and reduced, and an offset antenna with a snow melting device having a high communication line operating rate can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a detailed view of far-infrared ray generating means.

FIG. 3 is a detailed view of a cylindrical heater.

FIG. 4 is a detailed view showing another example of the cylindrical heater.

FIG. 5 is a diagram showing a temperature distribution on a reflecting mirror surface.

FIG. 6 is a diagram showing a state of a field test.

FIG. 7 is a diagram showing a second embodiment of the present invention.

FIG. 8 is a diagram showing a third embodiment of the present invention.

FIG. 9 is a diagram showing a conventional offset antenna.

FIG. 10 is a diagram showing a snow accretion state of a conventional offset antenna.

[Explanation of symbols]

1 offset reflecting mirror, 2 primary radiator, 3 frame, 4 stay, 5 transmission line, 6 outer ring, 7 frame, 8 AZ adjusting mechanism, 9 EL adjusting mechanism, 10 columns,
11 Far infrared ray generating means, 12 screws, 13 screws, 1
4 temperature measuring means, 15 control section, 16 power cable, 17 support rod, 18 screw, 19 adapter, 20
Adapter fixing bracket, 21 screw, 22 far infrared holder, 23a8-shaped sheathed heater, 23b cylindrical heater, 24 rotary parabolic or hemispherical reflector, 2
5 Nichrome wire, 26 Silicon rubber, 27 Far-infrared ray generating source, 28 Cover, 29 Fidome, 30 Far-infrared ray generating means, 31 Rod-shaped sheathed heater, 32 Columnar parabolic reflector, 33 Far-infrared ray source, 34 Far-infrared ray holder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumiaki Konishi Inventor Fumiaki Konishi 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Tatsuo Minagawa 325 Kamimachiya, Kamakura Mitsubishi Electric Corporation Kamakura (72) Inventor Toshio Masushima 325 Kamimachiya, Kamakura City Mitsubishi Electric Corporation Kamakura Factory (72) Inventor Akira Okuyama 325 Kamimachiya, Kamakura City Mitsubishi Electric Corporation Kamakura Factory

Claims (5)

[Claims] 1. An offset antenna comprising an offset reflecting mirror, a primary radiator arranged at a substantially focal point of the reflecting mirror, and a support for supporting the reflecting mirror, wherein the reflector has a primary radiator side and It is located outside the transmission path of radio waves from the focal point through the reflecting mirror, and irradiates far infrared rays from the lower side of the reflecting mirror so that the irradiation density of the lower part of the surface of the reflecting mirror is higher than that of other parts. An offset antenna with a snow melting device, characterized in that it comprises a far infrared ray generating means. 2. An offset antenna comprising an offset reflecting mirror, a primary radiator arranged at an approximate focal point of the reflecting mirror, and a support for supporting the reflecting mirror, wherein radio waves are transmitted from the focal point through the reflecting mirror. An offset antenna with a snow melting device, characterized in that it comprises a cylindrical heater located outside the road and behind the opening of the primary radiator and mounted around the primary radiator with a predetermined gap. . 3. An offset antenna comprising an offset reflecting mirror, a primary radiator arranged at an approximate focal point of the reflecting mirror, and a support for supporting the reflecting mirror, wherein the primary radiator side of the reflecting mirror and the It is located outside the transmission path of radio waves from the focal point through the reflecting mirror, and irradiates far infrared rays from the lower side of the reflecting mirror so that the irradiation density of the lower part of the surface of the reflecting mirror is higher than other parts. Far infrared ray generating means,
Outside the transmission path of radio waves from the focus to the reflector,
An offset antenna with a snow melting device, further comprising: a cylindrical heater located behind the opening of the primary radiator and mounted around the primary radiator with a predetermined gap. 4. The offset with a snow melting device according to claim 1, wherein the far infrared ray generating means is constituted by a figure-eight sheathed heater and a rotating parabolic or hemispherical reflector. antenna. 5. The offset antenna with a snow melting device according to claim 1, wherein the far infrared ray generating means is composed of one or a plurality of rod-shaped sheathed heaters and a columnar parabolic reflector. .