Reflection unit and wireless transmission system
A reflection unit of this disclosure is a reflection unit installed in a wireless transmission path between a first wireless device configured to at least transmit a wireless communication signal and a second wireless device configured to at least receive the wireless communication signal, in order to change a direction of the wireless transmission path. The reflection unit includes a plurality of reflectors configured to reflect the wireless communication signal. The plurality of reflectors include at least one reflectarray reflector.
1 . A reflection unit installed in a wireless transmission path between a first wireless device comprising a first antenna and being configured to at least transmit a wireless communication signal and a second wireless device comprising a second antenna and being configured to at least receive the wireless communication signal, in order to change a direction of the wireless transmission path,
the reflection unit comprising
a plurality of reflectors configured to reflect the wireless communication signal, wherein
the plurality of reflectors includes a plurality of reflectarray reflectors,
the plurality of reflectarray reflectors includes a first reflectarray reflector and a second reflectarray reflector,
the first reflectarray reflector is configured to reflect a second reflected wave, caused by the second reflectarray reflector, of a second wireless communication signal transmitted from the second wireless device,
the second reflectarray reflector is configured to reflect a first reflected wave, caused by the first reflectarray reflector, of a first wireless communication signal transmitted from the first wireless device,
the first reflectarray reflector includes
a first concentration reflection part configured such that the first reflected wave is concentrated at a focal point, and
a first non-concentration reflection part configured such that the first reflected wave is not concentrated, and
the second reflectarray reflector includes
a second concentration reflection part configured such that the second reflected wave is concentrated at a focal point, and
a second non-concentration reflection part configured such that the second reflected wave is not concentrated.
2 . The reflection unit according to claim 1 , wherein
the reflection unit is mountable to a structure having a corner where a first face and a second face are in contact with each other, and
the first reflectarray reflector is configured to be mounted to the first face; and the second reflectarray reflector is configured to be mounted to the second face.
3 . The reflection unit according to claim 1 , wherein
the plurality of reflectarray reflectors includes at least one non-diffusion reflectarray reflector configured such that the wireless communication signal is reflected in a non-diffused manner.
4 . The reflection unit according to claim 1 , wherein
the plurality of reflectarray reflectors includes
at least one diffusion reflectarray reflector configured such that the wireless communication signal is reflected in a diffused manner, and
at least one non-diffusion reflectarray reflector configured such that the wireless communication signal is reflected in a non-diffused manner.
5 . The reflection unit according to claim 3 , wherein
the at least one non-diffusion reflectarray reflector includes at least one concentration-type reflectarray reflector configured such that a reflected wave of the wireless communication signal is concentrated at a focal point.
6 . The reflection unit according to claim 5 , wherein
the reflection unit is mountable to a structure that has: a first portion; and a second portion where the wireless communication signal is more easily propagated than in the first portion, and
the concentration-type reflectarray reflector is mounted to the structure such that the reflected wave passes through the second portion.
7 . The reflection unit according to claim 5 , wherein
the concentration-type reflectarray reflector is configured such that the focal point is present at a position where an obstacle present in the wireless transmission path is avoided.
8 . The reflection unit according to claim 5 , wherein
the plurality of reflectors includes another reflector that further reflects the reflected wave caused by the concentration-type reflectarray reflector, and
the other reflector is smaller than the concentration-type reflectarray reflector.
9 . The reflection unit according to claim 1 , wherein
the first reflectarray reflector and the second reflectarray reflector are each one of a diffusion reflectarray reflector, a concentration-type reflectarray reflector, and a non-diffusion and non-concentration-type reflectarray reflector,
the second reflectarray reflector is one of the diffusion reflectarray reflector, the concentration-type reflectarray reflector, and the non-diffusion and non-concentration-type reflectarray reflector,
the diffusion reflectarray reflector is a reflectarray reflector configured such that the wireless communication signal is reflected in a diffused manner,
the concentration-type reflectarray reflector is a reflectarray reflector configured such that a reflected wave of the wireless communication signal is concentrated at a focal point, and
the non-diffusion and non-concentration-type reflectarray reflector is a reflectarray reflector configured such that: the wireless communication signal is not reflected in a diffused manner; and a reflected wave of the wireless communication signal is not concentrated at a focal point.
10 . The reflection unit according to claim 1 , wherein
the reflection unit is mountable to a structure having an installation surface, and
the second reflectarray reflector is configured to radiate the second reflected wave into a range including a direction orthogonal to the installation surface.
11 . The reflection unit according to claim 1 , wherein
the reflection unit further includes a radio wave absorber.
12 . The reflection unit according to claim 1 , wherein
the plurality of reflectarray reflectors further includes a multi-focal point reflectarray reflector, and
the multi-focal point reflectarray reflector is configured such that a first focal point in a first radiation plane included in a radiation range of a reflected wave of the wireless communication signal and a second focal point in a second radiation plane orthogonal to the first radiation plane are present at different positions.
13 . The reflection unit according to claim 1 , wherein
the first concentration reflection part and the second concentration reflection part are each implemented by a reflectarray including a plurality of reflection elements.
14 . The reflection unit according to claim 1 , wherein
the first non-concentration reflection part is configured to reflect the second reflected wave caused by the second concentration reflection part, and
the second non-concentration reflection part is configured to reflect the first reflected wave caused by the first concentration reflection part.
15 . The reflection unit according to claim 1 , wherein
the first reflectarray reflector includes a first low reflection region around the first non-concentration reflection part,
the first low reflection region has a reflectance lower than a reflectance, as to the second reflected wave, of the first non-concentration reflection part,
the second reflectarray reflector includes a second low reflection region around the second non-concentration reflection part, and
the second low reflection region has a reflectance lower than a reflectance, as to the first reflected wave, of the second non-concentration reflection part.
16 . The reflection unit according to claim 15 , wherein
the first low reflection region and the second low reflection region each include a radio wave absorber.
17 . The reflection unit according to claim 1 , wherein
the first concentration reflection part is formed in a ring shape,
the first non-concentration reflection part is disposed on an inner side of the first concentration reflection part,
the second concentration reflection part is formed in a ring shape, and
the second non-concentration reflection part is disposed on an inner side of the second concentration reflection part.
18 . The reflection unit according to claim 1 , wherein
the reflection unit is mountable to a structure having a corner where a first face and a second face are in contact with each other,
the first reflectarray reflector is mounted to the first face,
the second reflectarray reflector is mounted to the second face,
the first non-concentration reflection part is disposed at a position closer to the second face than the first concentration reflection part, or a position farther away from the second face than the first concentration reflection part, and
the second non-concentration reflection part is disposed at a position closer to the first face than the second concentration reflection part, or a position farther away from the first face than the second concentration reflection part.
19 . The reflection unit according to claim 1 , wherein
the first non-concentration reflection part is configured such that the first reflected wave is diffused, or is configured such that the first reflected wave is not diffused and is not concentrated, and
the second non-concentration reflection part is configured such that the second reflected wave is diffused, or is configured such that the second reflected wave is not diffused and is not concentrated.
20 . The reflection unit according to claim 19 , wherein
the first non-concentration reflection part and the second non-concentration reflection part are each implemented by a reflectarray including a plurality of reflection elements.
21 . The reflection unit according to claim 1 , wherein
the first non-concentration reflection part is attachable to and detachable from the first concentration reflection part, and
the second non-concentration reflection part is attachable to and detachable from the second concentration reflection part.
22 . The reflection unit according to claim 1 , embedded in a construction member.
23 . A reflection unit installed in a wireless transmission path between a first wireless device comprising a first antenna and being configured to at least transmit a wireless communication signal and a second wireless device comprising a second antenna and being configured to at least receive the wireless communication signal,
the reflection unit comprising
at least one concentration-type reflectarray reflector configured such that a reflected wave of the wireless communication signal is concentrated at a focal point, wherein the at least one concentration-type reflectarray reflector includes a first reflectarray reflector and a second reflectarray reflector,
the first reflectarray reflector is configured to reflect a second reflected wave, caused by the second reflectarray reflector, of a second wireless communication signal transmitted from the second wireless device,
the second reflectarray reflector is configured to reflect a first reflected wave, caused by the first reflectarray reflector, of a first wireless communication signal transmitted from the first wireless device,
the first reflectarray reflector includes
a first concentration reflection part configured such that the first reflected wave is concentrated at a focal point, and
a first non-concentration reflection part configured such that the first reflected wave is not concentrated, and
the second reflectarray reflector includes
a second concentration reflection part configured such that the second reflected wave is concentrated at a focal point, and
a second non-concentration reflection part configured such that the second reflected wave is not concentrated.
24 . The reflection unit according to claim 23 , wherein
the reflection unit is mountable to a structure that has: a first portion; and a second portion where the wireless communication signal is more easily propagated than in the first portion, and
one of the at least one concentration-type reflectarray reflector is mounted to the structure such that the reflected wave passes through the second portion.
25 . The reflection unit according to claim 23 , wherein
one of the at least one concentration-type reflectarray reflector is configured such that the focal point is present at a position where an obstacle present in the wireless transmission path is avoided.
26 . The reflection unit according to claim 23 , further comprising another reflector configured to further reflect the reflected wave, wherein
the other reflector is smaller than the concentration-type reflectarray reflector.
27 . A wireless transmission system comprising:
the first wireless device according to claim 1 configured to at least transmit the wireless communication signal;
the second wireless device according to claim 1 configured to at least receive the wireless communication signal; and
the reflection unit according to claim 1 installed in the wireless transmission path between the first wireless device and the second wireless device in order to change the direction of the wireless transmission path.