Patent Application
20140217248
The present invention relates to an antenna apparatus. More specifically, the present invention relates to an antenna apparatus (a tracking antenna) which tracks radio waves from a communication counterparty, such as a satellite, an earth station, or a mobile station, to control the direction of an antenna.
An example and conventional antenna apparatus which tracks radio waves from a communication counterparty to change the direction of an antenna is provided with a counter weight at the antenna-apparatus side of a base plate and a vibration isolation structure between the counter weight and the base plate (see, for example, Patent Literature 1). Moreover, there is a communication antenna apparatus having an AZ (azimuth)/EL (elevation) two-axis drive antenna or an AZ/cross-EL/EL three-axis drive antenna which ensures fixing of an antenna unit at the time of detaching a unit to improve the serviceability (see, for example, Patent Literature 2).
Regarding the placement of the counter weight, like the antenna apparatus disclosed in Patent Literature 1, it is apparent that both the antenna and the counter weight are provided at the same side of the base plate (see, for example, Patent Literatures 3 and 4). As disclosed in Patent Literature 5, an antenna apparatus, in which a counter weight is embedded to the lower end of its antenna, has a pivot located at the middle of the antenna and the antenna is provided to be able to rotate around the pivot. As a vibration isolation structure of an antenna apparatus, a helical isolator disclosed in, for example, Patent Literatures 6 to 8 is often used.
According to the antenna apparatuses disclosed in Patent Literatures 1 to 4, however, due to the structural constraint, it is difficult to position the centroid further closer to the base plate. According to the antenna apparatus disclosed in Patent Literature 5, the antenna and the counter weight are directly coupled with each other, and even if this structure is applied to a tracking antenna, the centroid cannot be made closer to the base plate.
The present invention has been made in order to solve the above-explained technical issue, and it is an objective of the present invention to provide an antenna apparatus which has a centroid close to a base, and which has a less constraint for placement of a counter weight.
To achieve the above objective of the invention, an aspect of the present invention provides an antenna apparatus that includes: a base that is fixed to a moving object or a structural object; an antenna unit which is disposed at a side of the base and which is supported by the base; and a counter weight unit which is disposed at a side of the base opposite to the antenna unit and which is supported by the base.
According to the present invention, the counter weight unit is supported at a side of the base opposite to the side where the antenna unit is disposed. Hence, the antenna apparatus can be obtained which has the centroid close to the base and which has a less constraint for placement of the counter weight.
An embodiment to carry out the present invention will be explained in detail with reference to the accompanying drawings. The same or corresponding component will be denoted by the same reference numeral throughout the figures.
An antenna apparatus includes an antenna unit 6, a base 10, and a counter weight unit 7. The antenna apparatus is used with the base 10 being fixed to a moving object or a structural object. Example moving objects are a vehicle like an automobile or a train, a ship, and an aircraft, such as an airplane, a helicopter, an airship, or a balloon. Example structural objects are a building of a satellite communication earth station, a cubicle containing thereinside a communication device, and a casing of the communication device. The moving object or the structural object to which the base 10 is fixed is referred to as an antenna apparatus mounting object.
The counter weight unit 7 is fixed to and supported by the base 10 through beams (beam: joist, column, cross member) 13a and 13b, etc. The antenna unit 6 is disposed at a side of the base 10, and is fixed to and supported by the base 10. The antenna unit 6 is covered by a radome 11 attached to the base 10. The base 10 includes a first base plate 5, a vibration isolation structure 8, and a second base plate 9. The first base plate 5 and the second base plate 9 are joined together via the vibration isolation structure 8 therebetween.
The antenna unit 6 includes a main mirror reflector 1 and an antenna driving unit 2. The antenna driving unit 2 includes a drive control unit 2b, an AZ/EL axis driving unit 3 and a POL axis driving unit 4. The antenna unit 6 also includes a low-noise amplifier (LNA) 6b.
The main mirror reflector 1 (reflecting mirror, parabola) reflects communication radio waves from a communication counterparty, such as a satellite, an earth station, or a mobile station, and concentrates the reflected radio waves to a primary radiator (at the time of reception). At this time, a sub mirror reflector may be additionally used. Moreover, at the time of transmission, a reverse operation, i.e., communication radio waves emitted from the primary radiator are reflected by the main mirror reflector 1, and are emitted toward the satellite, the earth station, or the mobile station, etc. The antenna driving unit 2 drives the main mirror reflector 1, and changes the direction of the main mirror reflector 1 relative to the base 10. The drive control unit 2b controls the antenna driving unit 2.
The AZ/EL axis driving unit 3 shown in
The low-noise amplifier (LNA) 6b suppresses an addition of noises of the communication radio waves received by the antenna unit 6 and amplifies the communication radio waves. The antenna unit 6 fulfills a major part of the tracking function of the antenna apparatus (the tracking antenna) which tracks radio waves from the communication counterparty, and which controls the direction of the main mirror reflector 1.
The radome 11 has an opening fixed to the base 10 (the first base plate 5) by fastening means, such as a screw or fit-in, and covers the antenna unit 6. In other words, the first base plate 5 includes the radome 11 covering the opposite side of the counter weight unit 7. The radome 11 permits radio waves for a communication by the antenna unit 6 to pass through.
The counter weight unit 7 is disposed at a side of the first base plate 5 opposite to the antenna unit 6, and is supported by the first base plate 5. The counter weight unit 7 fixed to the first base plate 5 serves to shift the centroid of the antenna apparatus closer to the first base plate 5. The vibration isolation structure 8 has a vibration isolation structural configuration having an end fixed to the first base plate 5. The vibration isolation structure 8 includes functional components, such as a spring and a damper. To the second base plate 9 other end of the vibration isolation structure 8 are fixed. The second base plate 9 is disposed between the first base plate 5 and the counter weight unit 7 and near the first base plate 5. The second base plate 9 is fixed to the moving object or the structural object, and thus the antenna apparatus of this embodiment is fixed. According to this embodiment, an explanation will be given of an example case in which the vibration isolation structure 8 is a helical isolator disposed between the first base plate 5 and the second base plate 9.
The counter weight unit 7 is fixed to the first base plate 5 through beams 13a, 13b, and 13c (see
At least one first beam fixing portion 14 to which respective one ends of the two beams 13 are fixed at a distance that can be regarded as a pin joint. Moreover, at least one second beam fixing portion 15 to which respective other ends of the two beams 13 are fixed at a distance that can be regarded as a pin joint. The distance that can be regarded as a pin joint means a distance that has a bending strain between joining points ignorable with respect to the bending strain of the beam 13. Moreover, the two beams 13 having respective one ends fixed to the same first beam fixing portion 14 have respective other ends fixed to the different second beam fixing portions 15. That is, at least some of the beams configure a truss structure.
The first beam fixing portion 14 and the second beam fixing portion 15 may be integral pieces with the first base plate 5 and the counter weight unit 7, respectively, or may be separate pieces. According to this embodiment, the first beam fixing portion 14 and the second beam fixing portion 15 are separate pieces from the first base plate 5 and the counter weight unit 7, respectively, and are fastened thereto by screws, which is shown in the figures.
The first beam fixing portion 14 and the second beam fixing portion 15 may be omitted as a structure of the beam 13 in some figures. Both of or either one of the first beam fixing portion 14 and the second beam fixing portion 15 may be an integral portion with the beam 13.
As shown in
The antenna apparatus of this embodiment utilizes the mass of the transmitting/receiving process unit as the counter weight of the antenna unit 6. When the mass as the counter weight is insufficient by only the transmitting/receiving process unit, in addition to the transmitting/receiving process unit, a component serving as a “weight” can be added. In this case, the counter weight unit 7 is configured by the transmitting/receiving process unit and the “weight”.
According to the antenna apparatus, since the transmitting/receiving process unit (the counter weight unit 7) is present outside the antenna unit 6 (the radome 11), and is supported by the base 10 through the beams 13 at a side opposite to the antenna unit 6, there is an advantageous effect from the standpoint of cooling. Moreover, the transmitting/receiving process unit is accessible without detaching the radome 11, and thus the maintenance is easy.
Since the transmitting/receiving process unit (the counter weight unit 7) is supported by the base 10 (the first base plate 5) through the plurality of beams 13, at least some of cables (signal lines and control lines, etc.,) interconnecting the transmitting/receiving process unit and the antenna unit 6 can be fixed to any of the plurality of beams 13.
When the transmitting/receiving process unit has a mass beyond the necessity as the counter weight unit 7, some of the circuits and boards for realizing the functions of the transmitting/receiving process unit may be disposed in an antenna apparatus mounting object or the antenna unit 6 for weight balancing. The above-explained “weight” can be used for fine adjustment of the weight balancing. Moreover, the mass of the beam 13 (including the first beam fixing portion 14 and the second beam fixing portion 15) and the number thereof can be utilized for the fine adjustment of the weight balancing. When the counter weight unit 7 fulfills at least some of the functions of the transmitting/receiving process unit, it can be regarded that the counter weight unit 7 includes the transmitting/receiving process unit.
As shown in
According to the antenna apparatus of this embodiment, since the counter weight unit 7 is provided at a side of the base 10 opposite to the antenna unit 6, in comparison with a case in which the counter weight is provided at the antenna-unit side of the base, the centroid can be made largely closer to the base. As a result, the antenna apparatus having the centroid close to the position where the antenna apparatus is fixed can be obtained.
According to the antenna apparatus exemplarily shown in
When the centroid of the antenna apparatus is located closer to the vibration isolation structure 8, with respect to vibration in the horizontal direction of the antenna apparatus, the antenna unit 6 displaces only in the translational direction, or mainly in the translational direction (line segment arrow in
The antenna apparatus shown in
According to the antenna apparatus shown in
The antenna apparatus shown in
Those structures facilitates formation of a fixing portion where the base support is fixed in comparison with the second base plate 9 (the base ring) shown in
As explained above, the antenna apparatus of this embodiment includes the counter weight unit 7 (the transmitting/receiving process unit) supported by the base 10 through the plurality of beams 13 at a side of the base 10 opposite to the antenna unit 6. The vibration isolation structure 8 having at least a portion disposed on the attaching surface at a position where the centroid of the configuration including the antenna unit 6 and the counter weight unit 7 (the transmitting/receiving process unit) is located suppresses a vibration of the antenna unit 6 and the counter weight unit 7 (the transmitting/receiving process unit). The vibration isolation structural configuration of this embodiment of the antenna apparatus has one end fixed to the antenna unit 6 or the beam 13 through the base 10 (the first base plate 5). It can be said that the antenna apparatus has the second base plate 9 that is a fixing component of the vibration isolation structure where other end of the vibration isolation structure 8 is fixed.
When the opening of the radome 11 of the antenna apparatus according to this embodiment is in a circular shape, it is preferable that the external shape of the base 10 should be also in a circular shape. According to the antenna apparatuses shown in
The counter weight unit 7 is attached at a side of the base 10 opposite to the antenna unit 6 by a truss structure (the plurality of beams 13). The antenna apparatus is mounted on the antenna apparatus mounting object through the vibration isolation structure 8 formed on the base 10 and a base support 12 (see
When, for example, the antenna apparatus is mounted on a communication station on the ground, a vehicle moving on the ground, or a ship sailing the ocean, the antenna unit 6 is disposed upwardly of the base 10 in most cases. In this case, the counter weight unit 7 is disposed downwardly of the base 10. When, for example, the antenna apparatus is mounted on an aircraft and communicates with a communication device on the ground, the antenna unit 6 is disposed downwardly of the base 10. In this case, the counter weight unit 7 is disposed upwardly of the base 10. In any cases, the centroid of the antenna apparatus of this embodiment is located close to the base 10 fixed to the moving object or the structural object, and the main mirror reflector 1 does not vibrate like a pendulum motion but takes a translational motion. Hence, the main mirror reflector 1 hardly tilts due to disturbance input, and the pointing error to the satellite, the earth station, and the mobile station, etc., is suppressed.
As is clear from the back view (
At the bottom of the base 10, the circular first base plate 5, and a hexagonal opening formed by cutting respective vertices of a triangle formed in the first base plate 5 can be seen. The second base plate 9 may have the same external shape as the shape of this opening. Moreover, a part of the helical isolator (the vibration isolation structure 8) disposed horizontally can be seen from a space between the first base plate 5 and the second base plate 9. A portion of the first base plate 5 where the first beam fixing portion 14 is fixed is referred to as a first beam fixing surface.
The helical isolators (the vibration isolation structure 8) are provided inwardly of the short sides of the hexagon formed by cutting respective vertices of the above-explained triangle. In other words, the helical isolators are disposed alternately at six sides forming the hexagon. In particular, in the case of
The base support 12 is to support the antenna apparatus of this embodiment, has one end fixed to the second base plate 9, and has other end fixed to the moving object or a structural object (not illustrated in figures) on which the antenna apparatus is mounted. The base support 12 is disposed at a location between the counter weight unit 7 and the second base plate 9, and supports the second base plate 9. Since the base support 12 is fixed to the second base plate 9, it can be regarded as the second base plate support.
The base support 12 includes a stage 12a, two columns 12c, and supporting columns 12d. The stage 12a is fixed to the second base plate 9. The two columns 12c are fixed to the stage 12a through a hinge 12b. The supporting column 12d supports the middle part of the column 12c. The columns 12c and the supporting columns 12d are fixed to the unillustrated object on which the antenna apparatus is mounted. The antenna apparatus of this embodiment including the base support 12 may be collectively referred to as an antenna apparatus.
The base support 12 has one end (the stage 12a) coupled with an area 9b of the base plate 9 shown in
As shown in
When a communication is established using the antenna apparatus of this embodiment, at the time of data transmission, transmission signals from the communication device is transmitted to the transmitting/receiving process unit (the counter weight unit 7) through the cable 7d. Next, such signals are transmitted to the antenna unit 6 from the transmitting/receiving process unit through the cables 7c. A tracking antenna is built in the antenna unit 6, and the antenna unit 6 transmits the transmission signals to, for example, a satellite. At the time of data reception, receiving signals are transmitted through the inversed route.
Since the antenna apparatus of this embodiment includes the counter weight unit 7 which is supported by the first base plate 5 at a side of the first base plate 5 opposite to a side where the antenna unit 6 is disposed, the antenna apparatus of this embodiment has the centroid located close to the first base plate 5 and has a less constraint for placement of the counter weight 7. Furthermore, the centroid located close to the first base plate 5, which is located at an end of the vibration isolation structure 8, and the vibration isolation structure 8 joining the first base plate 5 and the second base plate 9 accomplish a good vibration isolation function.
The above-explained embodiment can be changed and modified in various forms within the scope and spirit of the present invention. The above-explained embodiment is to explain the present invention, and is not intended to limit the scope and spirit of the present invention. It should be understood that the scope and spirit of the present invention is indicated by the appended claims rather than the embodiment. Various changes and modifications within the limitations in the claims and the equivalent thereto are also included in the scope and spirit of the present invention.
This application claims the benefit of a priority based on Japanese Patent Application No. 2011-189313 filed on Aug. 31, 2011, including the specification, claims, drawings, and abstract. The disclosure of this Japanese Patent Application is herein incorporated in this specification by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-189313 | Aug 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/068988 | 7/26/2012 | WO | 00 | 2/21/2014 |
