Patent Application
20240088569
The present disclosure relates to an antenna and a beam forming method.
Antennas that perform beam forming using liquid crystal are known (see, for example, Patent Literature 1).
In the aforementioned antenna, the beamforming may be slowed down due to the slow operation speed of the liquid crystal.
An object of the present disclosure is to provide an antenna and a beam forming method that solve the aforementioned problem.
An aspect of achieving the aforementioned object is an antenna comprising:
Another aspect of achieving the aforementioned object may be a beam forming method comprising changing an aperture shape of an opening part by moving a moveable member with respect to an opening part of a metasurface using a MEMS mechanism, thereby changing resonance conditions of the opening part and the moveable member and changing an electromagnetic radiation pattern radiated from the opening part.
According to the present disclosure, an antenna and a beam forming method that solve the aforementioned problem can be provided.
The present example embodiment will be described below with reference to the drawings.
The metasurface 3 has a multilayered structure, and at the top of the metasurface 3, at least one opening part 31 that receives electromagnetic waves is formed. The metasurface 3 has a plurality of opening parts formed, for example, in an array. While only the opening part 31 is shown in
The opening part 31 of the metasurface 3 is provided with at least one moveable member 4 that is operated with respect to the opening part 31. The moveable member 4 is made of metals or other materials that affect electromagnetic waves. The moveable member 4 is equipped with the MEMS mechanism 5 that operates the moveable member 4.
Here, a beam forming method according to the present example embodiment will be described. The MEMS mechanism 5 changes the aperture shape of the opening part 31 by operating the moveable member 4 with respect to the opening part 31 of the metasurface 3. Thus, beamforming can be performed by changing resonance conditions of the opening part 31 and the moveable member 4 and by changing the radiation pattern of the electromagnetic waves emitted from the opening part 31.
More specifically, the MEMS mechanism 5 of each opening part 31 performs beamforming by changing the aperture shape of each opening part 31 and changing the resonance conditions of each opening part 31 and each moveable member 4, thereby controlling the intensity of the electromagnetic waves emitted from each opening part 31.
For example, the shape of the opening part 31, the number of the opening parts 31, the shape of the moveable member 4, the number of the moveable members 4, the operation method of the moveable member 4, etc. are determined by design according to the desired electromagnetic radiation pattern.
The MEMS (Micro Electro Mechanical Systems) mechanism is a device with a micron-level structure in which sensors, actuators, electronic circuits, etc. of the mechanical component parts are integrated into a semiconductor silicon substrate, a glass substrate, and organic material, etc. It is advantageous to use such an elaborate MEMS mechanism 5 because the wire becomes thinner as the frequency increases.
The MEMS mechanism 5 is driven by a TFT (thin-film-transistor) or the like. The MEMS mechanism 5 has features that enable the moveable member 4 to move by an infinitesimal distance and at a high speed. In the antenna according to the present example embodiment, the shape of the opening part 31 is changed by having the moveable member 4 operate at a high speed using the high-speed operation features of the MEMS mechanism 5 described above.
This allows accelerated beamforming by changing the resonance conditions of the opening part 31 and the moveable member 4 and changing the electromagnetic radiation patterns emitted from the opening part 31 at high speed. Therefore, the antenna can be applied not only to satellite communication but also to a wide range of applications such as front holes for performing high-speed beamforming.
The MEMS mechanism 5 changes the aperture shape of the opening part 31 by moving the moveable member 4 in a parallel direction with respect to the opening part 31, thereby changing the resonance conditions of the moveable member 4 and the opening part 31. The MEMS mechanism 5 uses, for example, electrostatic force to move the moveable member 4 in a parallel direction with respect to the opening part 31.
As shown in
Here, the MEMS mechanism 5 displaces the moveable member 4 by only a few micrometers, but the metasurface 3 is sensitive to shape changes. Therefore, the resonance conditions of the moveable member 4 and the opening part 31 can be efficiently changed only by the infinitesimal displacement of the moveable member 4.
By causing infinitesimal displacement of the moveable member 4 in a parallel direction with respect to the opening part 31 as described above, the MEMS mechanism 5 switches between a radiation state in which the electromagnetic waves are radiated outward from inside the traveling wave tube 2 through the opening part 31 of the metasurface 3 and a non-radiation state in which the electromagnetic waves are not radiated outward from inside the traveling wave tube 2 through the opening part 31 of the metasurface 3.
The MEMS mechanism 5, for example, causes infinitesimal displacement of the moveable member 4 of the opening part 31 of the metasurface 3 in an upward vertical direction to switch from a non-radiant state (1) in which electromagnetic waves are not radiated from inside the traveling wave tube 2 through the opening part 31 of the metasurface 3 to a radiant state (2) in which electromagnetic waves are radiated from inside the traveling wave tube 2 through the opening part 31 of the metasurface 3.
The moveable member 4 has a first moveable member 43 provided on the lower side of the opening part 31 of the metasurface 3 so as to cover at least a part of the opening part 31 from the lower side thereof, and a second moveable member 44 provided on the upper side of the opening part 31 so as to cover at least a part of the opening part 31 from the upper side thereof.
The MEMS mechanism 5 changes the aperture shape of the opening part 31 three-dimensionally and changes the resonance conditions of the first and the second moveable members 43 and 44 and the opening part 31 by moving the first and the second moveable members 43 and 44 in a parallel direction with respect to the opening part 31.
The MEMS mechanism 5 may change the aperture shape of the opening part 31 by moving the first and the second moveable members 43 and 44 in a vertical direction with respect to the opening part 31, thereby changing the resonance conditions of the first and the second moveable members 43 and 44 and the opening part 31. In addition, the MEMS mechanism 5 may change the aperture shape of the opening part 31 by moving the first and the second moveable member 43 and 44 in a parallel direction and a vertical direction with respect to the opening part 31, thereby changing the resonance conditions of the first and the second moveable members 43 and 44 and the opening part 31.
In the present example embodiment, rough phase modulation can be performed by controlling the liquid crystal layer 6. Furthermore, minute phase modulation can be performed by operating the moveable member 4 using the MEMS mechanism 5 and changing the aperture shape of the opening part 31. By performing such two-stage phase modulation, high-speed and high-precision beamforming can be performed.
The metasurface 3 according to the aforementioned example embodiment is provided on the traveling wave tube 2, but it is not limited thereto. For example, the metasurface 3 may be provided on a highly directional antenna. More specifically, a plurality of highly directional micro-antennas may be arranged and the metasurface 3 may be provided on the antennas. The electromagnetic waves from the highly directional antennas may be subjected to high-speed beamforming by controlling the aperture shape of the opening part 31 of the metasurface 3 as described above.
The antenna 1 according to the aforementioned example embodiment can be utilized in a case where the antenna is to transmit electromagnetic waves, but it is not limited to this. That is, the antenna 1 according to the present example embodiment can also be utilized in a case where the antenna is to receive electromagnetic waves.
In the aforementioned example embodiment, an impedance-matching layer for performing impedance matching may be provided between the traveling wave tube 2 and the metasurface 3. The impedance-matching layer is composed of, for example, a conductor whose resistance can be changed. This impedance-matching layer allows for easy impedance matching.
While several example embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of present disclosure. These noble example embodiments can be implemented in a variety of other forms, and various omissions, replacements, and modifications can be made to the extent that they do not deviate from the gist of present disclosure. These and other variations are included in the scope and the gist of present disclosure and are equally within the scope of present disclosure described in the claims and the equivalents thereof.
This application is based upon and claims the benefit of priority from Japanese patent application No. 2021-056223, filed on Mar. 29, 2021, the disclosure of which is incorporated herein in its entirety by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-056223 | Mar 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/004276 | 2/3/2022 | WO |
