Communications: radio wave antennas – Antennas – With means for moving directive antenna for scanning,...
Reexamination Certificate
1999-12-17
2001-07-17
Ho, Tan (Department: 2821)
Communications: radio wave antennas
Antennas
With means for moving directive antenna for scanning,...
C343S765000, C343S91100R
Reexamination Certificate
active
06262688
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an antenna system and a method for controlling an antenna system, in particular, to an antenna system and a method for controlling an antenna system that can follow a plurality of communication satellites at substantially the same time.
2. Description of the Related Art
About 200 communication satellites have already gone around the earth at relatively low altitudes. Thus, we can communicate with at least some communication satellites wherever we are on the earth. The “Ilizium system” and the “Sky-bridge system” have already been proposed as systems using the communication satellites.
Parabola antenna systems or phased array antenna systems are generally used as conventional antenna systems for the communication satellites.
FIGS. 12 and 13
show an example of the conventional parabola antenna system. As shown in
FIG. 12
, the parabola antenna system
100
includes: a post
101
vertically standing on the ground or on a building; a rotatable shaft
102
mounted on an upper end of the post
101
in such a manner that the shaft
102
is parallel with and can rotate around an axis of the post
101
; a gear
102
g
fitted to the rotatable shaft
102
; and a gear
103
engaged with the gear
102
g
and driven by a motor (not shown).
An upper portion of a radio beam converging unit
120
is attached to a bracket
111
. The bracket
111
is supported by an upper end of the rotatable shaft
102
in such a manner that the bracket
111
can vertically pivot to the upper end of the rotatable shaft
102
. A lower portion of the radio beam converging unit
120
is attached to a front end of a movable rod
112
a
in a cylinder unit
112
. The cylinder unit
112
is fixed to a lower portion of the rotatable shaft
102
. An electric feeding unit
130
is disposed at a converged position into which a radio beam converges due to the radio beam converging unit
120
.
The above described parabola antenna system
100
operates as follows. The motor (not shown) is driven to rotate the rotatable shaft
102
via the gears
103
and
102
g,
in order to control a horizontal angle of the radio beam converging unit
120
. In addition, the cylinder unit
112
is actuated to slide the movable rod
112
to a desired position, in order to control an elevation angle of the radio beam converging unit
120
. Thus, the parabola antenna
100
can follow a communication satellite. That is, the radio beam converging unit
120
can face to the communication satellite to receive a radio beam outputted from the communication satellite in a good communication state, or to send a radio beam to the communication satellite in a good communications state.
As described above, the conventional parabola antenna system
100
has one radio beam converging unit
120
corresponding to one electric feeding unit
130
. Thus, when the number of satellites to follow is more than one, the same number of parabola antenna systems
100
are necessary. For example, when the number of satellites to follow is two, two parabola antenna systems
100
are necessary.
Then, the two parabola antenna systems
100
have to be arranged in such a manner that one or the other of the parabola antenna systems
120
may not be an obstacle between the other or the one of the parabola antenna systems
120
and the satellite corresponding to the one or the other of the parabola antenna system. For example, when each of the radio beam converging units
120
has a circular shape with a diameter of 45 cm, as shown in
FIG. 13
, the two radio beam converging units
120
have to be arranged substantially horizontally and away from each other at a distance of about 3 m. If not, one of the radio beam converging units
120
may shade the other of the radio beam converging units
120
.
However, the arrangement shown in
FIG. 13
requests a larger space. Thus, it is difficult to spread the arrangement to common houses.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide an antenna system that can follow a plurality of satellites and that is compact and capable of being arranged in a smaller space.
To achieve the above object, this invention is characterized by following features. That is, this invention is an antenna system including; a plurality of antenna devices respectively configured to send or receive a plurality of radio beams, a plurality of electric feeding units respectively holding the plurality of antenna devices, a spherical lens having a center and causing the plurality of radio beam to converge into the plurality of antenna devices respectively, and a holding rail holding the plurality of electric feeding units in such a manner that the plurality of antenna devices are movable along a substantially constant distance from the center of the spherical lens.
According to the feature, the plurality of electric feeding units (the plurality of the antenna devices) can be arranged for one spherical lens to follow the plurality of satellites. Thus, the antenna system can be arranged in a smaller space.
Preferably, the antenna system further includes: a fixed base, a rotational base mounted on the fixed base and rotatable around a first axis through the center of the spherical lens, and a supporting element fixed on the rotational base and supporting the holding rail rotatably around a second axis which is perpendicular to the first axis and which passes through the center of the spherical lens.
In the case, the antenna system may prevent interference in the movements of the plurality of electric feeding units with each other. Especially, when the number of the electric feeding units is two, the interference in the movements of the two electric feeding units may be extremely effectively prevented.
Preferably, the plurality of antenna devices are capable of substantially adjoining to each other when the plurality of electric feeding units come close to each other.
The supporting element also may support the spherical lens.
The holding rail may have an arc-shaped arm, at least one of whose ends is supported by the supporting element.
The antenna system may include a controlling unit configured to control a rotation of the rotational base around the first axis, a rotation of the arc-shaped arm around the second axis and a movement of each of the plurality of electric feeding units along the holding rail.
The antenna system may include conductors respectively connected with the electric feeding units, wherein the conductors pass through a portion of the rotational base substantially adjacent to the first axis toward the fixed base. In the case, each of the conductors may have an optical transmitting device in order to transmit an optical signal between the rotational base and the fixed base. Preferably, the optical transmitting device can transmit a plurality of optical signals at a time by using lights having different wavelengths.
Preferably, the antenna system may include a cover wall sealingly covering the plurality of electric feeding units, the spherical lens and the holding rail. In the case, the antenna system may include a lens holding member attached to the cover wall and holding the spherical lens. Alternatively, the spherical lens may be supported by the cover wall. The cover wall may be made of a material having a low thermal conductivity. Alternatively, the cover wall may consist of a layer configured to reflect infrared rays, a layer configured to absorb light and an insulating layer. In addition, the cover wall may have a window which is made of a material having a lower transmittance for infrared rays than for visible rays.
In addition, this invention is characterized by following features. That is, this invention is a method of controlling an antenna system comprising: two antenna devices respectively configured to send or receive two radio beams, two electric feeding units respectively holding the two antenna devices, a spherical lens having a center and causing the two radio beams to converge into the two antenna devices respectively, a ho
Alemu Ephrem
Ho Tan
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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