JP2909175B2 - Antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an antenna device suitable for use as an earth station of a communication / broadcasting satellite system installed in, for example, a snowfall area.

(Prior Art) In recent years, with the commencement of satellite communication technology and broadcasting satellite services, a large number of earth stations using antenna devices such as parabolic antennas and Cassegrain antennas have been installed. Aperture Termina
l) With the spread of the system, it is expected that many earth stations will be installed.

By the way, such an antenna device, due to its structure,
When the reflector is installed upward in the snowfall area for satellite reception at an elevation angle of about 45 °, snow accumulates on the reflector and the feeder, causing the antenna beam direction to shift and signal attenuation to occur. There is a problem that when the frequency increases and attenuation exceeding the line margin occurs, the line is disconnected.

For example, in a broadcasting satellite receiving system, miniaturization of an antenna device is promoted, and since there is only a line margin of 1 to 2 dB, attenuation of 5 to 6 dB has been confirmed in a snow cover of about 15 cm, and a line disconnection of half a day to 1 There are many things that last a day. Further, in a satellite communication system in which the reliability of the line is severe, the line disconnection time due to snow accumulation is often not anticipated in advance, and it is necessary to minimize the direct line disconnection.

For this reason, in the conventional antenna device, a snow melting heater is disposed on the back of the reflecting mirror, and the snow melting heater is selectively driven by an operator according to weather conditions to prevent snow accretion, or to prevent snowfall. Snow melting means for driving a snow melting heater using a snowfall sensor for detecting the snowfall has been taken.

However, the above-described snow melting means has a problem in that the snow melting time is delayed or a malfunction occurs due to the configuration of melting the snow that has arrived by driving the snow melting heater, and it is difficult to perform highly reliable snow melting. Further, according to this, since the snow melting heater is used to melt the snow that has reached the reflecting mirror, the power consumption is increased, the equipment is complicated, and the cost is extremely high. This is a major problem, especially as the size of the earth station in the VSAT system becomes smaller and the demand for lowering the price of the entire system increases because the snow melting means becomes extremely expensive compared to the price of the entire system. Become.

(Problems to be Solved by the Invention) As described above, the conventional antenna device has a problem that the reliability of the snow melting operation by the snow melting means is low, the power consumption increases, and the equipment becomes expensive. Was.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an antenna device that has a simple configuration and is capable of reliably realizing highly reliable snow melting.

[Constitution of the Invention] (Means and Action for Solving the Problems) The present invention is directed to an antenna device in which a feeder is disposed to face a front surface of a parabolic reflecting mirror via a support member, and the front surface of the reflecting mirror is provided. A first cover member made of a radio wave permeable material having a radio wave transmission surface that is negatively inclined with respect to a vertical line when the reflector is installed, and covers the power supply unit A surface facing the power supply surface of the power supply unit is opened, and in the installed state on the power supply unit, one vertex of the open surface corresponds to a vertical line, and the open surface is the vertical surface. And a second cover member formed of a substantially triangular pyramid-shaped radio wave transmitting material having a negative inclination with respect to the line.

According to the above configuration, the first cover member prevents the falling snow from directly accumulating on the reflecting mirror surface because the radio wave transmitting surface facing the front surface of the reflecting mirror is negatively inclined. Thus, snowfall on the radio wave transmitting surface is prevented. Therefore, snow accumulation on the reflecting mirror surface is effectively prevented, and signal attenuation by the reflecting mirror due to snowfall is prevented. At the same time, the second
The cover member prevents direct snow accumulation on the power supply unit, and the surface of the power supply unit facing the power supply surface is formed with a negative slope, thereby preventing snow accumulation on the surface. Therefore, snow accumulation on the power supply unit is effectively prevented, and signal attenuation by the power supply unit due to snowfall is prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an antenna device according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes a parabolic reflector used for BS reception or a VSAT system. This reflecting mirror 10 is
As shown in the figure, a predetermined angle is inclined with respect to a vertical line L1 so as to face a satellite X in an elevation direction (for example, 40 ° to 50 °) via a column 12 erected on a gantry 11 to face the sky. The power supply unit 13 including the LNA unit is mounted on the mirror surface of the support member 1.
It is inclined at a predetermined angle with respect to the vertical line L2 via 4 and is arranged to face the same. The intermediate portion of the support member 14 excluding the reflector mounting end is separated from the peripheral edge of the reflector 10 by a predetermined distance D (see FIG. 2), and the snowfall of falling snow is prevented. . In this case, it is particularly effective to form the support member 14 in a plate shape so that the end faces upward.

Then, a cover member 15 is attached to the mirror surface of the reflecting mirror 10. The cover member 15 is a substantially cylindrical cone with a bottom having a radio wave transmitting material, for example, a foamable polymer material as a base material 16 and a thin film 17 of about 0.2 mm made of a polymer material such as a fluororesin. It is formed into a shape. The bottom surface 15a facing the reflecting mirror surface of the cover member 15 is in the installed state of the reflecting mirror 10,
A radio transmission surface having a negative inclination (overhang) which is inclined in the ground direction by an angle θ1 with respect to the vertical line L1 is formed, and prevents snow from accumulating on the reflecting mirror surface. It is confirmed that the cover member does not accumulate on the radio wave transmitting surface of the cover member even in wet snow falling almost vertically in a windless state occurring in Sapporo in the middle of December, for example. Also, 1-2
Similarly, even in dry snow with a low temperature of the moon, it is confirmed that the radio wave transmitting surface of the cover member hardly snows and does not affect the transmission and reception of radio waves.

The cover member 15 has a flange-shaped mounting portion 15 for mounting a reflecting mirror.
b is provided. The mounting portion 15b is formed at a predetermined angle corresponding to the beam passing line 18, and the mounting portion 15b
b is attached to the reflecting mirror 10 using a screw 19. As a result, the cover member 15 is attached so as to be negatively inclined with respect to the reflecting mirror surface as described above. The mounting portion 15b is manufactured by molding a polymer material such as FRP and CFRP using a mold. In addition, a foamable polymer material such as foamable styrene can be molded using a metal mold as an attachment.

In addition, since it is confirmed that the expandable polystyrene has a strength to withstand a load exceeding 10 tons per square meter, the use of the expandable polymer material for the mounting portion 15b is advantageous in terms of weight reduction. Is also effective.

Further, the power supply unit 13 is formed in a substantially triangular shape in which a thin film 17 of a polymer material such as a fluororesin is adhered to a base material 16 made of a radio wave transmitting material, for example, a foamable polymer material. The cover member 20 is attached using screws (not shown) or the like so as to cover the cover member 20. The cover member 20 is formed with a negative inclination (overhang) in which the power supply surface that transmits the radio wave is oriented in the ground direction by an angle θ2 with respect to the vertical line L2 when the power supply unit 13 is installed. The cover member 20 has a heating wire 21 constituting a snow melting means, for example, 1 cm so as not to attenuate a signal to at least two surfaces which are exposed to the sky.
Wires are provided at intervals, and a thin film 17 made of a polymer material such as the above-mentioned fluororesin is applied on the heating wires 21 (see FIG. 3).

In addition, the cover members 15 and 20 may be detached from the screw 19 appropriately in a season in which there is no possibility
And the power supply unit 13.

The heating wire 20 constitutes a snow melting means, and the operation of the heating wire 20 is controlled by a snowfall sensor unit including a temperature sensor 22 such as a thermistor and a moisture sensor 23. The temperature sensor 22 and the moisture detection sensor 23 are disposed, for example, on the column 12, and are disposed outdoors. The moisture sensor 23 includes a sensor section 23a and a heater section 23b whose peripheral portions are formed substantially vertically for falling snow as shown in FIG. At the upper end of 12, an inclination angle of α (45 ° to 60 °) with respect to a direction substantially perpendicular to the vertical line L1 is provided via a mount 23c made of a heat-insulating polymer material. The reason why the moisture sensor 23 is inclined by α is to wash away dust and dirt attached to the detection surface and to quickly detect moisture in a state where snow has stopped. On the other hand, the temperature sensor 22 is attached to the column 12 using the case 22a.

That is, the heating wire 20 has its input end connected to the fixed end a of the relay circuit 24 constituting the control section as shown in FIG. 5, and the movable contact b of the relay circuit 24 connected to the voltage V2. . And, the signal input terminal of this relay circuit 24 is AND
Connected to the output of circuit 25. The AND circuit 25 has the first
The output end of the temperature detection module 26 is connected to the input end of
The output terminal of the moisture detection module 27 is connected to the second input terminal. The temperature detection module 26 is connected to the output end of the temperature sensor 22. For example, the temperature detection module 26 has a snowfall temperature (about 0 ° to 3 °) and a slightly higher temperature (7 ° to 10 °).
゜) two types are detected, and in the state where the high temperature is detected,
The control signal is output to a relay circuit 28 connected to the output terminal. The relay circuit 28 has a heater 23b of the moisture sensor 23 connected to the fixed contact thereof, a voltage source V2 connected to the movable contact b thereof, and when a control signal is inputted, the movable contact b
Is connected to the fixed contact a to supply a current to the heater section 23b.

On the other hand, a moisture sensor is provided at the input end of the moisture detection module 27.
The output terminals of the 23 sensor units 23a are connected. Moisture sensor 23
As shown in FIG. 6, the moisture sensor 23a is disposed on a dielectric substrate 23d, for example, a pair of comb electrodes 23e having a line interval of 100 μm to 500 μm are opposed to each other. When moisture is deposited, the volume changes,
The change capacity is output to the moisture detection module 27. The heater 23b is stacked on the sensor 23a. The heater section 23b is formed by disposing a heating element 23f of, for example, a NiCr wire or a heating fiber on a glass-epoxy dielectric substrate 23g, heating the sensor section 23a and causing snow to fall on a detection surface thereof. Is dissolved to detect the amount of water.

The relay circuit 24 and the AND circuit 2 that constitute the control unit
5, the temperature detection module 26, the moisture detection module 27, the relay circuit 28, for example, is disposed indoors,
An effective distance between these arrangements is 20 m to 25 m with respect to the snowfall sensor unit in consideration of display errors of the temperature detection module 26 and the like.

With the above configuration, the AND circuit 25 is connected to the temperature detection module 26
Detects a snowfall temperature, and outputs a control signal to the relay circuit 24 when the moisture detection module 27 detects snowfall. Then, the relay circuit 24 supplies the current of the voltage V1 to the heating wire 20 to heat the cover member 20, and melts, for example, snow that has accumulated snow.

Thus, the above antenna device is a parabolic reflector.
In the installation state of the reflecting mirror 10 on the front surface of 10, a cover member 15 formed of a radio wave permeable material having a radio wave transmission surface that is negatively inclined with respect to the vertical line L1 is attached, and on the power supply surface of the power supply unit 13 A cover member 20 made of a substantially triangular-shaped radio wave permeable material whose opposite surface has a negative inclination with respect to the vertical line L2 in the installed state of the power supply unit 13 is attached so as to cover the power supply unit 13. Of these, the snow melting means is provided only on the cover member 20 of the power supply unit 13. According to this, since the radio wave transmitting surface facing the front surface of the reflecting mirror 10 is negatively inclined, the cover member 15 prevents the snowfall of the snowfall from directly accumulating on the reflecting mirror surface. Since snowfall on the radio wave transmitting surface is prevented, signal attenuation due to the reflector due to snowfall is prevented. At the same time, the cover member 20 prevents direct snow accumulation on the power supply unit 13 and, because the surface of the power supply unit 13 facing the power supply surface is formed with a negative slope, the power supply unit 13 associated with snowfall. Signal is prevented from being attenuated. For example, in the case of wet and concentrated snow in the northern country or dry snow blown with a dry northwest wind, the reflecting members 1 and 20 are used by the cover members 15 and 20.
It is possible to effectively prevent the snow from accumulating on the power supply unit 13 and the power supply unit 13 and contribute to improving the reliability of signal transmission / reception during snowfall.

Further, according to this, the snow melting means is provided only on the cover member 20 attached to the power supply unit 13, and it is not necessary to dispose a heater on the back surface of the reflecting mirror as in the related art, so that power saving can be achieved as much as possible. In addition, simplification of the configuration is realized.

In the above-described embodiment, the cover members 15 and 20 are attached to the reflector 10 and the power supply unit 13. However, the present invention is not limited to this, and is disposed in, for example, an area where the amount of snowfall is relatively small. In this case, even when the cover member 15 is attached to only the reflecting mirror 10, it is possible to effectively prevent signal attenuation similarly.

Further, in the above embodiment, the cover member 20 attached to the power supply 13 is provided with the snow melting means. However, the present invention is not limited to this. Even if it is configured without any means, it is possible to effectively prevent signal attenuation.

Further, in the above embodiment, the cover members 15 and 20 are
As a means for attaching to the power supply unit 13 and 0, it is configured to be attached using a screw 19, but is not limited to this, for example, an elastic engagement portion is provided on the cover members 15 and 20, and this elastic engagement portion is used. It is also possible to adopt a configuration in which it is attached to the reflection mirror 10 and the power supply unit 13.

Further, in the above embodiment, the case where the present invention is applied to transmission and reception of signals using a satellite such as a satellite broadcasting system or a satellite communication system has been described. However, the present invention is not limited to this, and can be applied to various types of terrestrial antennas. The same effect is expected.

Further, in the above-described embodiment, a thin film 17 made of a radio wave permeable material was applied to the surface using a radio wave permeable foamable polymer material as the base material 16 to form the cover members 15 and 20 for weight reduction. However, the present invention is not limited to this, and it is also possible to use a radio wave transmitting material such as a radio wave transmitting polymer material on the surface of which snow is unlikely to snow.

Therefore, it is needless to say that the present invention is not limited to the above-described embodiment, and that various modifications can be made without departing from the scope of the present invention.

[Effects of the Invention] As described above in detail, according to the present invention, it is possible to provide an antenna device with a simplified configuration and capable of reliably realizing highly reliable snow melting.

[Brief description of the drawings]

1 is a perspective view showing an antenna device according to one embodiment of the present invention, FIG. 2 is a cross-sectional view showing details of FIG. 1, FIG. 3 is a cross-sectional view showing details of a cover member of FIG. FIG. 4 shows the first
FIG. 5 is an enlarged perspective view showing the moisture sensor of FIG. 5, FIG. 5 is a circuit diagram showing details of the snow melting means of FIG. 1, and FIG. 6 is an exploded perspective view showing details of the moisture sensor of FIG. 10 ... Reflector, 11 ... Stand, 12 ... Support, 13 ... Power supply, 14 ... Support member, 15,20 ... Cover member, 15a ... Bottom surface, 15b ... Mounting part, 16 ... Base material, 17 …… Thin film, 18 ……
Beam passing line, 19 screw, 21 heating line, 22 temperature sensor, 22a case, 23 moisture sensor, 23a sensor unit, 23b heater unit, 23c mounting base, 23d, 23g…
... Dielectric substrate, 23e ... Comb-shaped electrode, 23f ... Heating element, 2
4,28 relay circuit, 25 AND circuit, 26 temperature detection module, 27 moisture detection module.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-224506 (JP, A) JP-A-48-17653 (JP, A) JP-A-63-283204 (JP, A) JP-A-2- 44803 (JP, A) JP-A-2-97101 (JP, A) JP-A-60-93303 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01Q 1 / 02,1 / 42

Claims (6)

(57) [Claims] 1. An antenna device comprising a parabolic reflector and a feeder disposed opposite to a front surface of the reflector via a support member. The antenna device covers the front surface of the reflector. A first cover member formed of a radio wave permeable material having a radio wave transmission surface that is negatively inclined with respect to the line; and a first cover member that covers the power supply unit, and a surface of the power supply unit facing the power supply surface is open. When installed in the power supply unit, a substantially triangular pyramid-shaped radio wave transmission in which one vertex of the open surface corresponds to a vertical line and the open surface has a negative slope with respect to the vertical line And a second cover member formed of a conductive material. 2. The antenna device according to claim 1, wherein said first and second cover members are formed using a foamable polymer material as a base material. 3. The antenna device according to claim 1, wherein the support member has an intermediate portion other than a reflector support end separated from a peripheral portion of the reflector. 4. The apparatus according to claim 1, wherein said second cover member includes snow melting means for melting snow attached to two surfaces sandwiching one vertex located at least on a vertical line of the open surface. 4. The antenna device according to any one of 1 to 3, wherein 5. The snow melting means includes: a heating wire buried in the second cover member; moisture detecting means for detecting the amount of water to detect the presence or absence of snowfall; A temperature detecting means for detecting whether or not the temperature has reached a snowfall temperature; and driving the heating element in response to the detection of the snowfall by the moisture detecting means and the detection of the reaching of the snowfall temperature by the temperature detecting means. The antenna device according to claim 4, further comprising: heating control means for controlling heating of the cover member (2). 6. The moisture detecting means, wherein a peripheral portion of the detecting portion is formed in a substantially vertical shape, and is inclined by 40 ° to 60 ° with respect to a direction substantially perpendicular to the vertical line via a heat insulating material. 6. The antenna device according to claim 5, wherein the antenna device is installed at a position higher than the amount of snow in the state.