WO2023223895A1 - Système de transmission d'ondes radio et procédé de recherche de terminal de réception - Google Patents

Système de transmission d'ondes radio et procédé de recherche de terminal de réception Download PDF

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Publication number
WO2023223895A1
WO2023223895A1 PCT/JP2023/017440 JP2023017440W WO2023223895A1 WO 2023223895 A1 WO2023223895 A1 WO 2023223895A1 JP 2023017440 W JP2023017440 W JP 2023017440W WO 2023223895 A1 WO2023223895 A1 WO 2023223895A1
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WIPO (PCT)
Prior art keywords
reflection
radio wave
reflector
reflecting
radio waves
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PCT/JP2023/017440
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English (en)
Japanese (ja)
Inventor
翔 熊谷
裕 宇井
眞平 長江
修 加賀谷
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Ａｇｃ株式会社
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Publication of WO2023223895A1 publication Critical patent/WO2023223895A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/10—Auxiliary devices for switching or interrupting
    • H01P1/15—Auxiliary devices for switching or interrupting by semiconductor devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures

Definitions

  • the present disclosure relates to a radio wave transmission system and a receiving terminal search method.
  • metasurface reflector array that is constructed by arranging a plurality of metasurface reflectors.
  • Each of the N metasurface reflectors has the same directional characteristic of the radio wave intensity of the reflected radio wave when a radio wave of wavelength ⁇ is incident at a predetermined incident angle, and two metasurface reflectors adjacent to each other have the same
  • the phase difference of the radio waves transmitted is a predetermined value ⁇ different from 0. Interference with other communication devices is suppressed when reflected waves are reflected to areas (coverage holes) with weak radio wave intensity that occur behind buildings or the like that shield radio waves (see, for example, Patent Document 1).
  • a radio wave transmission system includes a reflector having a plurality of reflection plates capable of scanning reflection angles, and a control unit configured to scan reflection angles of the plurality of reflection plates.
  • Each has a first length L1 in the first axial direction and a second length L2 in the second axial direction, and the plurality of reflecting plates are arranged along the first axial direction and the second axial direction.
  • control unit controls the radio waves reflected by the plurality of reflecting plates when the reflection angle is set to the first reflection angle.
  • the reflection angle is scanned to a second reflection angle such that at least one of the plurality of peaks is located at a position between the plurality of intensity peaks.
  • FIG. 2 is an explanatory diagram of the operation of the radio wave transmission system 10 in an embodiment of the present disclosure.
  • 1 is a block diagram showing an example of the configuration of a radio wave transmission system 10.
  • FIG. 3 is a diagram showing an example of a state in which the radio wave transmission system 10 is attached to a wall 6.
  • FIG. 1 is a diagram showing an example of the configuration of a reflector 100.
  • FIG. It is a figure showing an example of arrangement of a plurality of cells of reflector 100R.
  • FIG. 3 is a diagram illustrating an example of the principle of adjusting the reflection angle on a reflection plate 100R included in the reflector 100.
  • FIG. 3 is a diagram illustrating an example of the principle of adjusting the reflection angle on a reflection plate 100R included in the reflector 100.
  • FIG. 3 is a diagram showing an example of the configuration of a cell 110.
  • FIG. It is a figure which shows the state of the resonant element 112 in the on state and off state of PIN diode 112C. It is a figure which shows the state of the resonant element 112 in the on state and off state of PIN diode 112C.
  • FIG. 7 is a diagram illustrating an example of the on/off distribution of each cell 110 when controlling the amount of phase change of the reflector 100R using binary values.
  • FIG. 3 is a diagram showing a polar coordinate system used when calculating the radar reflection cross section ⁇ ( ⁇ , ⁇ ). 10 is a diagram showing how to take the angle ⁇ (horizontal angle) of the horizontal axis in FIG. 9.
  • FIG. 7 is a diagram illustrating an example of a difference in beam width due to a difference in planar size of the reflecting plate 100R.
  • FIG. 7 is a diagram illustrating an example of a difference in beam width due to a difference in planar size of the reflecting plate 100R.
  • 11A is a diagram showing an example of a simulation result of the angular distribution of reflected waves of a reflecting plate 100R having the planar size explained using FIG. 11A.
  • FIG. 11A is a diagram showing an example of a simulation result of the angular distribution of reflected waves of a reflecting plate 100R having the planar size explained using FIG. 11A.
  • FIG. It is a figure showing reflector 100 of radio wave transmission system 10 of an embodiment. It is a figure which shows the reflector 1 for comparison.
  • FIG. 3 is a diagram showing an example of simulation results of the intensity distribution of radio waves of the reflector 100 and the comparative reflector 1.
  • FIG. 2 is a diagram illustrating an example of a method of searching for a receiving terminal in the radio wave transmission system 10.
  • FIG. 2 is a diagram illustrating an example of a method of searching for a receiving terminal in the radio wave transmission system 10.
  • FIG. 5 is a diagram showing an example of a simulation result obtained by scanning the intensity distribution of radio waves reflected by the reflector 100.
  • FIG. 3 is a diagram illustrating an example of a simulation result obtained by scanning the intensity distribution of radio waves reflected by a comparative reflector 1.
  • the direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are orthogonal to each other.
  • the X direction is an example of a first axis direction
  • the Y direction is an example of a second axis direction
  • the Z direction is an example of a third axis direction.
  • the ⁇ Z direction side may be referred to as the lower side or lower side
  • the +Z direction side may be referred to as the upper side or upper side.
  • planear view refers to viewing in the XY plane.
  • radio wave is a type of electromagnetic wave, and generally, electromagnetic waves of 3 THz or less are called radio waves.
  • electromagnetic waves emitted from outdoor base stations or relay stations will be referred to as “radio waves,” and when referring to electromagnetic waves in general, they will be referred to as “electromagnetic waves.”
  • millimeter wave or millimeter wave band includes not only the frequency band of 30 GHz to 300 GHz, but also the quasi-millimeter wave band of 24 GHz to 30 GHz.
  • the radio waves reflected by the reflector of the embodiment are preferably radio waves in the millimeter wave band of the fifth generation mobile communication system (5G), or in the frequency band of 1 GHz to 40 GHz, including Sub-6. Further, the radio waves reflected by the reflector of the embodiment may be LTE (Long Term Evolution), LTE-A (LTE-Advanced), or UMB (Ultra Mobile Broadband). In addition, the radio waves reflected by the reflector of the embodiment include IEEE802.11 (Wi-Fi (registered trademark)), IEEE802.16 (WiMAX (registered trademark)), IEEE802.20, UWB (Ultra-Wideband), Bluetooth ( (registered trademark) or LPWA (Low Power Wide Area). As the frequency of radio waves increases, propagation loss due to reflection and diffraction increases, and dead zones are more likely to occur. Therefore, the reflector of the embodiment is more suitable for communications that handle relatively high frequencies.
  • FIG. 1 is an explanatory diagram of the operation of a radio wave transmission system 10 according to an embodiment of the present disclosure.
  • the radio wave transmission system 10 of the present disclosure is placed, for example, on a wall or window of an outdoor building BD.
  • the radio wave transmission system 10 includes a reflector 100 (see FIG. 2), and the reflector 100 of the present disclosure is called a RIS (Reconfigurable Intelligent Surface) and can adjust the directivity of a beam. This is a directional control array.
  • the type of building BD in which the radio wave transmission system 10 is placed is arbitrary, it is, for example, a building in an area where there are many high-rise buildings. In areas where there are many high-rise buildings, dead zones (areas or spaces with poor communication environment, also known as ⁇ dead zones'') where radio waves do not reach properly are likely to occur.
  • the radio wave transmission system 10 of the present disclosure transmits radio waves to a dead area by controlling the direction of a reflected radio wave beam.
  • a wireless base station RB may be provided to perform wireless communication.
  • the radio base station RB converts a signal from a network (not shown) such as the Internet into a radio signal, and transmits radio waves R, so that a receiving terminal receives the radio waves R. Further, by receiving radio waves R transmitted by the receiving terminal at the radio base station RB, the receiving terminal can access a network such as the Internet.
  • the radio base station RB may be provided close to the radio wave transmission system 10 by several tens of centimeters to several meters, or may be provided several tens of meters to several kilometers away from the radio wave transmission system 10. Good too.
  • the radio wave transmission system 10 of the present disclosure changes the beam direction of the incident radio wave R, directs the beam in a specific direction and reflects it, or makes it into a multi-beam, thereby achieving a dead zone blocked by the building BD.
  • radio waves are plane waves unless otherwise specified.
  • the radio wave transmission system 10 it is possible to select an outdoor user terminal U1 and an outdoor user terminal U2 to communicate over the Internet. Specifically, for example, a radio wave R transmitted from the wireless base station RB at a certain time is reflected by the radio wave transmission system 10 and received by the user terminal U1 outdoors, thereby establishing wireless communication of the user terminal U1. can. The radio waves R transmitted from the radio base station RB at different times are reflected by the radio wave transmission system 10 and received by the user terminal U2 outdoors, thereby making it possible to establish radio communication with the user terminal U2.
  • FIG. 1 shows an example in which a wireless base station RB is provided in addition to the radio wave transmission system 10, even if the radio waves coming from a wireless relay station etc. are reflected by the reflector 100 of the radio wave transmission system 10, good.
  • FIG. 2 is a block diagram showing an example of the configuration of the radio wave transmission system 10.
  • FIG. 3 is a diagram showing an example of a state in which the radio wave transmission system 10 is attached to the wall 6.
  • FIG. 2 shows a state in which the reflector 100 directly reflects radio waves arriving from the wireless base station RB.
  • the radio wave transmission system 10 includes a reflector 100 and a control section 5.
  • the control unit 5 of the present disclosure is realized by, for example, an MCU (Micro Controller Unit), and includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), input/output Includes interfaces, internal buses, etc.
  • MCU Micro Controller Unit
  • CPU Central Processing Unit
  • RAM Random Access Memory
  • ROM Read Only Memory
  • the control unit 5 receives an incident wave source position (including the direction of arrival of a plane wave by setting it to infinity) and a reflection direction instruction (directivity instruction) from the outside, and controls the reflection angles of the plurality of cells of the reflector 100, respectively. Control. Inputs from outside the control unit 5 are input from, for example, a management computer (not shown) that manages the building BD, a wireless base station RB, and the like. Note that the control unit 5 operates based on a power supply voltage generated by a power generation unit (not shown).
  • the radio wave transmission system 10 (reflector 100 and control unit 5) is provided on the wall 6.
  • the height from the ground is preferably 1 m to 14 m, particularly preferably 2 m to 10 m, from the viewpoint of radio wave efficiency.
  • FIG. 3 shows an example in which the radio wave transmission system 10 is placed on the wall 6, the reflector 100 in the radio wave transmission system 10 may be placed on a window glass.
  • the substrate of the reflecting plate and the resonant element included in the reflector 100 are made of a transparent member having a visible light transmittance of 50% or more.
  • the control unit 5 may be placed at another location apart from the reflector 100, such as a wall adjacent to the window glass or a frame of the window glass. Good too.
  • the radio wave transmission system 10 of the present disclosure may be installed on an indoor wall or window glass. In that case, it contributes to reducing the dead zone indoors.
  • FIG. 4 is a diagram showing an example of the configuration of the reflector 100.
  • the reflector 100 includes, for example, four reflecting plates 100R.
  • the configuration of the four reflectors 100R is the same, and they are arranged at the four corners of a square area A of 2 m x 2 m, for example, with a certain distance between them. That is, the length of the reflector 100 in the X direction and the Y direction is, for example, 2 m in FIG. 4.
  • the length of the reflector 100 in the X direction and the Y direction is preferably 3 m or less, more preferably 2 m or less. For this reason, in FIG. 4, 2 m is shown as an example.
  • the reflector 100 may include a plurality of reflecting plates 100R, and the number of reflecting plates 100R can be any number as long as it is 2 or more. It may be.
  • the plurality of reflecting plates 100R included in the reflector 100 may be arranged with a certain distance between them.
  • Each of the plurality of reflecting plates 100R included in the reflector 100 as a RIS also functions as a RIS, and is a directivity control array that can adjust the directivity of the beam.
  • a configuration in which all the plurality of reflecting plates 100R included in the reflector 100 are arranged with a certain amount of space between each other will be described, but at least one of all the plurality of reflecting plates 100R Some of the reflecting plates 100R may be arranged with a certain distance between them.
  • a fifth reflector 100R may be provided at the center of the four reflectors 100R shown in FIG. 4 or at the center of the upper row.
  • the reflection plate 100R can adjust the reflection angle of the radio wave to an angle other than specular reflection or to an angle of specular reflection by controlling the amount by which the phase is changed (phase change amount) when reflecting the radio wave.
  • the amount of phase change of the reflection plate 100R can be controlled in a binary manner or in a multivalued manner that is more than two values.
  • the reflection plate 100R reflects the radio wave in a predetermined reflection direction, which is a predetermined reflection direction, by controlling the amount of phase change and adjusting the reflection angle.
  • the unnecessary reflections of each reflecting plate 100R are canceled out, and unnecessary reflections of the plurality of reflecting plates 100R can be reduced as a whole. Since the plurality of reflectors 100R included in the reflector 100 of the radio wave transmission system 10 are arranged at certain intervals, in the following, when controlling the phase change amount of the reflector 100R in a binary manner, The explanation will be given assuming that unnecessary reflections are reduced.
  • FIG. 5 is a diagram showing an example of the arrangement of a plurality of cells of the reflection plate 100R.
  • FIG. 5 describes a case in which vertically polarized radio waves are reflected, the same applies to horizontally polarized waves.
  • a case will be described in which the phase of radio waves is controlled in a binary manner.
  • the reflector 100R has a plurality of regularly arranged cells 110.
  • the cells 110 are configured as repeating units, and in FIG. 5, for example, ten cells 110 are arranged in the X direction and the Y direction. This is because if ten cells 110 are arranged in each of the X direction and the Y direction, the reflection angle of the reflected wave can be adjusted.
  • the arrangement of the plurality of cells 110 is not limited to the array shown in FIG. 5, but may be arranged randomly (irregularly) without regularity, for example.
  • Ten or more cells 110 are arranged in the X direction and the Y direction, and the number of cells 110 arranged in the X direction and the Y direction is preferably 130 or less, and more preferably 100 or less.
  • each cell 110 has resonant elements 111 and 112.
  • the cell 110 is an example of a reflective section
  • the resonant element 111 is an example of a first resonant element
  • the resonant element 112 is an example of a second resonant element.
  • the resonant element 111 is a resonant element that can resonate independently at a predetermined resonant frequency.
  • the resonant element 112 includes a switching element that can switch the resonant frequency to the first resonant frequency or the second resonant frequency by electrical control, but this is omitted in FIG. 5. Details of the cell 110 will be described later using FIG. 7.
  • the reflection plate 100R can set the angle at which the incident radio waves are reflected in a desired direction. Details of turning on and off the cell 110 will be described later using FIGS. 7 and 8, but a switching element that can switch the resonant frequency of the resonant element 112 to the first resonant frequency or the second resonant frequency by electrical control is used.
  • a state in which the cell 110 is turned on is a state in which the cell 110 is turned on
  • a state in which the switching element is turned off is a state in which the cell 110 is turned off.
  • cells 110 that are on are shown in white, and cells that are off are shown as filled dots.
  • the cell 110 is an active cell whose ON/OFF state is controlled by the control unit 5 .
  • phase shifter is an example of a phase adjustment section.
  • phase shifter it is preferable to use liquid crystal, ferroelectric material, or the like.
  • a phase shifter can change the phase of a radio wave to any continuous value, and is therefore suitable for multi-level control.
  • FIGS. 6A and 6B are diagrams illustrating an example of the principle of adjusting the reflection angle at the reflection plate 100R included in the reflector 100.
  • the reflector 100R is an array called RIS (Reconfigurable Intelligent Surface: reconfigurable reflector) that can adjust the directivity of the beam.
  • RIS Reconfigurable Intelligent Surface: reconfigurable reflector
  • d is the pitch between adjacent cells 110 in the X direction.
  • FIGS. 6A and 6B in order to make it easier to understand how radio waves are incident and reflected in adjacent cells 110 on the XZ plane, the positions where the radio waves are incident on the reflective surface (surface on the +Z direction side) of the reflective plate 100R, The position where the light is emitted from the reflective surface is shown separately, shifted in the X direction.
  • the radio waves are By setting the amount by which the phase is changed (phase change amount) when reflecting radio waves for each cell 110, the direction in which radio waves are reflected by all the cells 110 included in one reflector 100R can be adjusted.
  • the reflecting plate 100R adjusts the propagation direction of the beam, which is the reflected wave, by changing the phase of the radio wave when reflecting the radio wave in each of the plurality of cells 110 arranged in an array.
  • the reflection direction is changed by adding a phase to each cell 110. That is, by adding a phase to each location X of the reflector 100R, the direction of reflection of the radio wave can be changed.
  • a radio wave emitted from a point F at coordinates (Xf, Yf, Zf) is incident on a point at coordinates (X, Y, 0) on the reflective surface of the reflector plate 100R, and is reflected.
  • the amount of phase change ⁇ (X, Y) applied to the radio wave on the reflective surface of the reflector plate 100R when reaching the point P of (Xp, Yp, Zp) can be expressed by the following equation (1) .
  • the constant k is 2 ⁇ / ⁇
  • ⁇ is the wavelength of radio waves in free space.
  • the coordinates (Xp, Yp, Zp) are called a focal point in the sense of a point where radio waves are collected in order to receive them.
  • Equation (1) the distribution of the amount of phase change is nonlinear with respect to the position X. If point F and point P are sufficiently far apart, equation (1) can be approximated by a linear equation with respect to the coordinates X and Y on the reflecting surface.
  • FIG. 6B also shows radio waves that are incident on adjacent cells 110 at a pitch d in the X and Y directions at a zenith angle ⁇ in and an azimuth angle ⁇ in, and are reflected by the reflector 100R in the direction of a zenith angle ⁇ out and an azimuth angle ⁇ out.
  • This shows how the radio waves seen in the XZ plane.
  • the zenith angle and the azimuth angle are represented by the zenith angle ⁇ and the azimuth angle ⁇ in FIG. 12A, which will be described later.
  • the radio waves incident on adjacent cells 110 at pitch d are parallel, and the incident angles are both zenith angle ⁇ in and azimuth angle ⁇ in
  • the radio waves reflected by the reflection surface of the reflection plate 100R are also parallel, and the reflection angles are both the zenith angle ⁇ out and the azimuth angle ⁇ out.
  • the phase difference between radio waves incident on adjacent cells 110 at pitch d is, for example, d ⁇ sin ⁇ in ⁇ cos ⁇ in in the X direction
  • the phase difference between radio waves reflected by adjacent cells 110 at pitch d is d ⁇ sin ⁇ out. ⁇ cos ⁇ out.
  • the phase difference between radio waves incident on adjacent cells 110 at pitch d is, for example, d ⁇ sin ⁇ in ⁇ sin ⁇ in in the Y direction
  • the phase difference between radio waves reflected by adjacent cells 110 at pitch d is, for example, d ⁇ sin ⁇ in ⁇ sin ⁇ in.
  • the phase difference is d ⁇ sin ⁇ out ⁇ sin ⁇ out.
  • equation (2) is obtained by approximating equation (1) using the zenith angle ⁇ in and azimuth angle ⁇ in of incidence and the zenith angle ⁇ out and azimuth angle ⁇ out of reflection, and ignoring constant terms that do not depend on X and Y. .
  • the cell 110 is controlled to approximately realize the phase difference within the reflector 100R, so that the incident light enters the reflector 100. It is possible to reflect the received radio waves in a desired direction. Note that when controlling the cells 110, the same result can be obtained even if the same value is added to all cells 110 for the phase change amount ⁇ (X, Y) expressed by equation (1). .
  • the cell 110 that can continuously control the amount of phase change during reflection using a voltage, it is possible to realize the amount of phase change ⁇ (X, Y) while eliminating errors, and the direction of reflection can be controlled in the reflection plate 100R. It can be changed.
  • the cell 110 that can control the amount of phase change during reflection with binary values depending on on and off voltages, it is possible to approximately realize the amount of phase change ⁇ (X, Y), and in the reflector 100R. The direction of reflection can be changed.
  • ⁇ (X,Y) In order to realize the amount of phase change ⁇ (X,Y) in each cell 110 that can switch between the on state and the off state, if the phase difference during reflection between the on state and the off state can be ensured by approximately 180 degrees, the amount of phase change If ⁇ (X, Y) is between -90° and 90°, it is in the off state, and when it is between -180° and -90° or between 90° and 180°, it is in the on state, thereby changing the amount of phase change. ⁇ (X,Y) can be approximately realized, so that the reflection direction can be changed in each cell 110. This holds true in both equations (1) and (2).
  • Selection of the on state and the off state from the above-mentioned phase change amount ⁇ (X, Y) is just an example, and it is sufficient to select the on state and the off state within a range of 180 degrees that do not overlap each other. For example, from 20° to 180° or from -180° to -160° may be an off state, and from -160° to 20° may be an on state.
  • the radio wave transmission system 10 can change the direction of the radio waves emitted from a 5G base station, etc., direct the beams in various directions or any desired direction, or make them into multi-beams. You can also.
  • FIGS. 6A and 6B show radio waves reflected within the XZ plane, as described above, the reflector 100 can reflect radio waves within the YZ plane, or Radio waves can be similarly reflected when reflected within a plane having an angle to the YZ plane. Therefore, the reflector 100 becomes a reflector whose reflection angle can be set to an angle other than specular reflection.
  • the on or off state of all the cells 110 changes in the X direction within each row, and is arranged in the Y direction within each column.
  • a state in which ten cells 110 are uniformly turned on or off is shown. This corresponds to the case where the on state and off state are determined based on equation (2).
  • the arrangement of the cells 110 in the reflector 100R shown in FIG. 5 is an example, and the number of cells 110 provided in the array may be approximately several tens to several thousand.
  • FIG. 7 is a diagram showing an example of the configuration of the vertically polarized cell 110.
  • the cell 110 is a cell that controls the phase change amount with binary values of on and off, and includes one resonant element 111 and one resonant element 112 adjacent to the one resonant element 111.
  • FIG. 7 shows a substrate 101.
  • the substrate 101 is the substrate 101 of the reflecting plate 100R (see FIG. 4), and one reflecting plate 100R includes one substrate 101.
  • the size of the substrate 101 in plan view is the size shown in FIG. 4 as a reflection plate 100R.
  • a ground layer is provided on the surface of the substrate 101 on the ⁇ Z direction side.
  • the reflector 100R includes a plurality of cells 110.
  • FIG. 7 shows a portion of the entire substrate 101 that corresponds to one cell 110. Note that the cell 110 for horizontal polarization has a configuration obtained by rotating the cell 110 shown in FIG. 7 by 90 degrees clockwise or counterclockwise.
  • one reflecting plate 100R includes one substrate 101
  • a configuration in which one reflecting plate 100R includes a plurality of substrates 101 may be used. That is, one substrate 101 may be provided for one or more cells 110 in one reflecting plate 100R.
  • the substrate 101 is, for example, a rectangular substrate in plan view.
  • the substrate 101 is, for example, a flexible resin-made thin film-like flexible substrate, or a non-flexible rigid substrate. Flexibility is the property of an object to bend without breaking, as can be seen from its appearance.
  • a flexible substrate for example, fluorine, COP (Cyclo-Olefin Polymer), PET (Polyethylene terephthalate), PEN (Polyethylene Naphthalate), polyimide, Peek (Polyether ether Ketone), LCP (Liquid Crystal Polymer) It can be formed from a flexible resin material such as , or other composite materials.
  • a rigid substrate for example, a substrate made of a core material and a prepreg made of glass cloth impregnated with an epoxy resin or the like can be used.
  • the substrate 101 may be formed of any material that is transparent to radio waves emitted from an outdoor base station or the like. “Transparent” means that the transmittance is at least 40% or more, preferably 60% or more, more preferably 70% or more, and still more preferably 80% or more.
  • a transparent resin base material is used for the substrate 101.
  • acrylic resins such as polymethyl methacrylate, cycloolefin resins, polycarbonate resins, polyethylene terephthalate (PET), etc. can be used.
  • the substrate 101 may be a glass plate.
  • Resonant elements 111 and 112 are formed of metal layers.
  • the metal layer can be formed of a metal thin film such as copper, nickel, or gold, if the substrate 101 is not formed of any material transparent to radio waves.
  • the metal layer may be made of, for example, zinc oxide (ZnO), tin oxide (SnO 2 ), tin-doped indium oxide (ITO), or It is formed of a transparent conductive film such as indium tin oxide (IZO), a metal nitride such as titanium nitride (TiN) or chromium nitride (CrN), or a low-e film for low emissivity glass. is desirable.
  • the metal layer may be made of a mesh-like metal thin film of copper, nickel, gold, or the like, for example.
  • the resonant element 111 is a square conductor in plan view.
  • the resonant element 111 has an end side 111A extending along the X direction on the +Y direction side.
  • a resonant element 112 is parasitic to the resonant element 111 . Since the resonant element 112 is coupled to and parasitic to the resonant element 111 by electromagnetic coupling, the resonant element 111 may be regarded as a main resonant element and the resonant element 112 as a parasitic resonant element.
  • the resonant element 112 includes linear elements 112A and 112B and a PIN (p-intrinsic-n) diode 112C.
  • the PIN diode 112C is an example of a switching element.
  • Linear elements 112A and 112B extend parallel to the X direction.
  • the linear element 112A is arranged on the +Y direction side of the end side 111A of the resonant element 111, and the linear element 112B is arranged on the +Y direction side of the linear element 112A.
  • a PIN diode 112C is provided between the linear elements 112A and 112B.
  • a cathode of a PIN diode is connected to the linear element 112A
  • an anode of a PIN diode 112C is connected to the linear element 112B.
  • RF chokes 113 and 114 are provided at the ends of the linear elements 112A and 112B on the ⁇ X direction side.
  • the RF choke 113 is connected to a ground layer of a ground potential (GND) on the back surface of the substrate 101, and the RF choke 114 is connected to a control terminal to which a control voltage BV is applied.
  • the control voltage BV is applied from the control section 5 (see FIG. 2).
  • the distance between the end side 111A of the resonant element 111 and the linear element 112A is preferably ⁇ e/10 or less, for example. ⁇ e/30 is more preferable. ⁇ e is the electrical length of the wavelength at the frequency of the radio wave reflected by the reflection plate 100R.
  • the length of the region in which the resonant elements 111 and 112 are provided in one cell 110 in the X direction and the Y direction in plan view is 2 ⁇ or less.
  • a square resonant element 111 is shown in FIG. 7, if the dimensions in the X and Y directions are not constant, such as when the resonant element 111 is elliptical, the The maximum length in the X direction and the maximum length in the Y direction in plan view of the region where the resonant elements 111 and 112 are provided need only be 2 ⁇ or less.
  • FIGS. 8A and 8B are diagrams showing the states of the resonant element 112 in the on state and off state of the PIN diode 112C.
  • the linear element 112B is connected to the linear element 112A, so as shown in FIG. 8A, the resonant element 111 Then, the linear elements 112A and 112B of the resonant element 112 are in a coupled state.
  • the state in which the linear elements 112A and 112B of the resonant element 112 are coupled to the resonant element 111 as shown in FIG. 8A has a higher resonance than the state in which only the linear element 112A is coupled to the resonant element 111 as shown in FIG. 8B.
  • the length of the element 112 increases and the shape changes. Therefore, when the PIN diode 112C is turned on as shown in FIG. 8A, the resonant frequency of the resonant element 112 is lowered to the first resonant frequency than when the PIN diode 112C is turned off. On the contrary, when the PIN diode 112C is turned off as shown in FIG.
  • the resonant frequency of the resonant element 112 increases to the second resonant frequency compared to when the PIN diode 112C is on. It is known that when two resonant elements having approximately the same resonant frequency are placed close to each other, their reflection characteristics change due to interaction. When the resonant frequency of the resonant element 111 is approximately the same as either the first resonant frequency or the second resonant frequency of the resonant element 112, the resonant elements 111 and 112 are switched on and off by switching the PIN diode 112C on and off. By changing the overall shape (or length), the reflection characteristics of the cell 110 change.
  • the size of the resonant elements 111 and 112 is set so that the absolute value of the amount of phase change given to the radio wave as an incident wave is approximately 180 degrees when the PIN diode 112C is off and on.
  • linear elements 112A and 112B of the resonant element 112 are set.
  • About 180 degrees means, for example, a value within the range of 180 degrees ⁇ 45 degrees. Since the resonant elements 111 and 112 are made of conductors, there may be errors in the amount of phase change due to manufacturing errors, etc. However, by switching the PIN diode 112C on and off, the amount of phase change can be adjusted to approximately 180 degrees (180 degrees ⁇ 45 degrees).
  • Specular reflection refers to regular reflection, and refers to reflection in a direction in which an equal phase plane is generated by reflection by ordinary metal reflection.
  • the reflection plate 100R can switch the reflection angle (reflection direction) of the incident wave on the reflection plate 100R as a set of all cells 110 by turning on and off the PIN diode 112C of each cell 110. That is, in the reflector 100R, the control unit 5 can control the amount of phase change in a binary manner by switching on and off the PIN diode 112C of each cell 110, and the reflection angle can be changed to an angle other than specular reflection. Adjustable. Specular reflection refers to regular reflection, and refers to reflection in a direction in which an equal phase plane is generated by reflection by ordinary metal reflection. Note that the reflection angle of the reflection plate 100R can also be adjusted to the angle of specular reflection.
  • the phase change amount of the cell 110 is 30 degrees when the PIN diode 112C is turned off, and the phase change amount of the cell 110 is 210 degrees when the PIN diode 112C is turned on. It can be controlled in a binary manner.
  • the phase change amount of 30 degrees is an example of the first value
  • the phase change amount of 210 degrees is an example of the second value.
  • the difference between the amount of phase change when the PIN diode 112C is off and the amount of phase change when it is on is approximately 180 degrees (180 ⁇ 45 degrees) in absolute value. That is, the difference between the first value and the second value of the amount of phase change is 180 ⁇ 45 degrees in absolute value.
  • the difference in phase change amount of all cells 110 is 0 degrees. In reality, there is some variation, so the difference in the amount of phase change is about 0 degrees. This also applies when the PIN diodes 112C of all the cells 110 are turned on.
  • the amount of phase change of all the cells 110 (for example, 30 degrees and 210 degrees) The difference is 180 degrees. In reality, since there is some variation, the difference in the amount of phase change is approximately 180 degrees.
  • the resonant element 111 has a square shape and the resonant element 112 has a PIN diode 112C between two linear elements 112A and 112B.
  • the shape of the resonant element 111 is not limited to a square shape, and may have any planar shape as long as it can reflect radio waves.
  • the resonant element 112 may have any configuration as long as its shape and length can be changed by being switched by the control unit 5.
  • the diode 112C is not limited to the PIN diode 112C, and may be a transistor such as a MEMS (Micro Electro Mechanical Systems) switch, a varactor, or a FET (Field Effect Transistor).
  • FIG. 9 is a diagram showing an example of the on/off distribution of each cell 110 in the case where the amount of phase change of the reflector 100R is controlled using binary values.
  • FIG. 9 shows, as an example, the on/off distribution in the reflection plate 100R including 40 cells 110 in the X direction and the Y direction, for a total of 1600 cells.
  • FIG. 9 shows the distribution of ON and OFF states in a linear arrangement, and in FIG. 9, ON is shown in white and OFF is shown in black for simplification.
  • the amount of phase change that the cell 110 that is on adds to the reflected wave is 180 degrees
  • the amount of phase change that the cell 110 that is off adds to the reflected wave is 0 degrees.
  • the reflective plate 100R used in the simulation was arranged so that the reflective surface of the cell 110 was in the XY plane.
  • the cells 110 of the reflector 100R have a length of dX in the X direction and dY in the Y direction.
  • NX cells 110 are arranged at equal intervals of dX in the X direction
  • NY cells 110 are arranged at equal intervals of dY in the Y direction. That is, the number of cells 110 is NX ⁇ NY, the length of the reflecting plate 100R in the X direction is NX ⁇ dX, and the length in the Y direction is NY ⁇ dY.
  • the row number of the cell 110 in the X direction as n
  • the column number of the cell 110 in the Y direction as m
  • the number of the cell 110 can be specified by n and m.
  • the radar reflection cross section ⁇ ( ⁇ , ⁇ ) can be determined using the following equation (3).
  • a polar coordinate system shown in FIG. 10A is used.
  • FIG. 10A is a diagram showing a polar coordinate system used when calculating the radar reflection cross section ⁇ ( ⁇ , ⁇ ).
  • the reflection plate 100R is located at the origin of the XYZ coordinates.
  • the zenith angle ⁇ is an angle with respect to the +Z direction, and the angle downward from the +Z direction as shown by the arrow is positive.
  • the azimuth angle ⁇ is an azimuth angle with respect to the +X direction in the XY plane, and the angle from the +X direction to the +Y direction as shown by the arrow is positive.
  • r is the radius vector.
  • a receiving point G is shown in FIG. 10A.
  • a receiving point G represents the position of a receiving terminal that receives radio waves from the reflector 100R.
  • the receiving terminal is a user terminal or the like.
  • r is the distance (m) from the reflection plate 100R to the receiving point G, and is the vector radius in the polar coordinate system.
  • P0 is the power density (W/m 2 ) of a radio wave (incident wave) that is incident on the reflection plate 100R.
  • Pr is the power density (W/m 2 ) at the receiving point G.
  • the electric field E at the point (X, Y) of the radius vector r can be calculated using the following equation (4).
  • A is the distribution of the complex electric field immediately after being reflected from the RIS
  • s is the distance between the position on the reflection plate 100R and the receiving point
  • Q is the electric field reflection intensity distribution for each reflection direction of the cell. Note that RIS means that integration is performed over the entire reflection plate 100R.
  • Equation (4) the size of the cell 110 is used for discretization, and the position of the cell 110 is specified using n and m.
  • ⁇ the power density
  • the radar reflection cross section ⁇ ( ⁇ , ⁇ ) expressed by equation (3) can be determined.
  • ⁇ ( ⁇ , ⁇ ) as shown in FIGS.
  • FIG. 10B is a diagram showing how to take the angle ⁇ (horizontal angle).
  • the angle ⁇ is an angle with respect to the +Z direction in the Represents direction as a negative angle. Note that the method of determining the vector radius r is the same as the method of determining the vector radius r in FIG. 10A.
  • FIGS. 11A and 11B are diagrams illustrating an example of a difference in beam width due to a difference in planar size of the reflecting plate 100R.
  • the plane size is the length of the reflecting plate 100R in the X direction and the Y direction.
  • FIG. 11A shows a beam B formed by radio waves reflected by a reflecting plate 100R having lengths of 20 cm in both the X and Y directions.
  • FIG. 11B shows a beam B formed by a radio wave reflected by a reflecting plate 100R having a length of 40 cm in both the X direction and the Y direction.
  • the beam B of the reflector 100R whose lengths are 40 cm in both the X and Y directions shown in FIG. It is thought that the beam width will be narrower.
  • FIGS. 12A and 12B are diagrams showing an example of simulation results of the angular distribution of reflected waves of the reflecting plate 100R having the planar size described using FIGS. 11A and 11B, respectively.
  • the horizontal axis represents the reflection angle ⁇ (degrees)
  • the vertical axis represents RCS (radar reflection cross section) (dBm 2 ). Note that the set reflection direction is +25 degrees.
  • RCS represents the intensity of reflected waves. Note that the frequency of the radio waves is 28 GHz, for example.
  • the angle ⁇ at which the peak with the highest intensity exists was in the range of about 23 degrees to about 27 degrees, for example, where the RCS was 15 dBm 2 or more.
  • the RCS ratio between the highest intensity peak in the +25 degree direction and the lower intensity peaks on both sides was about 13 dB to about 15 dB.
  • the angle ⁇ at which the peak with the highest intensity exists was in the range of about 24 degrees to about 26 degrees, with the RCS being 27 dBm 2 or more, as an example.
  • the RCS ratio between the highest intensity peak in the +25 degree direction and the lower intensity peaks on both sides was about 13 dB to about 25 dB.
  • Beam B shown in FIGS. 11A and 11B corresponds to the peak with the highest intensity in FIGS. 12A and 12B, respectively. From the simulation results in FIGS. 12A and 12B, it is clear that the beam B of the reflector 100R, which has a length of 20 cm in both the X and Y directions shown in FIG. 11A, has a length of 40 cm in both the X and Y directions shown in FIG. 11B. It was confirmed that the beam width of the beam B of the reflector 100R was narrower. It is considered that the width of the beam B becomes narrower as the planar size of the reflecting plate 100R becomes larger.
  • FIG. 13A is a diagram showing the reflector 100 of the radio wave transmission system 10 of the embodiment.
  • FIG. 13B is a diagram showing the reflector 1 for comparison.
  • the reflector 100 shown in FIG. 13A is the same as the reflector 100 shown in FIG. 4, and includes four reflecting plates 100R as an example.
  • the four reflecting plates 100R are arranged with a certain distance Dw between them in the X direction and the Y direction.
  • the length L1 in the X direction of each reflecting plate 100R is, for example, 40 cm or less
  • the length L2 in the Y direction is, for example, 40 cm or less.
  • length L1 and length L2 are 20 cm as an example, but length L1 and length L2 are preferably within a range of 10 cm to 40 cm.
  • the free space wavelength ⁇ at 28 GHz is set to about 1 cm
  • the length of the cell 110 in the X direction and the Y direction in plan view is 0.5 ⁇
  • there are 40 cells 110 in each of the X direction and the Y direction If they are arranged, the length L1 and the length L2 will be about 20 cm.
  • the state where a certain distance Dw is left between each other means that the distance Dw between adjacent reflecting plates 100R is, for example, 0.2 ⁇ L1 or more in the X direction and 0.2 ⁇ L2 or more in the Y direction. It means that.
  • the interval Dw is preferably 0.2 x L1 or more in the X direction and 0.2 x L2 or more in the Y direction, and is preferably 1.2 x L1 or more in the X direction and 1.2 x L2 or more in the Y direction. It is more preferable that In FIG. 13A, as an example, the distance Dw is 20 cm and is equal to the lengths L1 and L2.
  • the comparative reflector 1 shown in FIG. 13B includes four reflectors 100R like the embodiment reflector 100 shown in FIG.
  • the reflectors 100 are different from the reflectors 100 of the embodiment in that they are arranged at intervals of less than 0.2 ⁇ L1 in the X direction and less than 0.2 ⁇ L2 in the Y direction, without spacing Dw. More specifically, as an example, the interval between the four reflection plates 100R is 0 mm.
  • FIG. 14 is a diagram showing an example of a simulation result of the radio wave intensity distribution of the reflector 100 and the comparative reflector 1.
  • the horizontal axis represents the reflection angle ⁇ (degrees)
  • the vertical axis represents RCS (dBm 2 ).
  • RCS is a value calculated using equation (3).
  • the intensity distribution of the radio waves reflected by the reflector 100 is shown by a solid line, and the intensity distribution of the radio waves from the comparative reflector 1 is shown by a broken line.
  • the set reflection direction is +25 degrees.
  • 19 peaks included in the intensity distribution of the radio waves reflected by the reflector 100 are numbered 1 to 19 in order from the left side. The peak with the highest intensity located in the set reflection direction is No. 11.
  • the RCS of the highest intensity peak (No. 11) located in the set reflection direction in the intensity distribution of the radio waves reflected by the reflector 100 is located in the set reflection direction in the intensity distribution of the radio waves reflected by the comparison reflector 1. It is approximately equal to the RCS of the highest intensity peak, about 27 dBm2 . Also, the width of the peak (number 11) with the highest intensity among the radio waves reflected by the reflector 100 (the width of the angle ⁇ ) is the width of the peak with the highest intensity among the radio waves reflected by the comparative reflector 1. Narrower than the width (width of angle ⁇ ). This is similar to the results shown in FIGS. 12A and 12B.
  • the intensity distribution of the radio waves reflected by the reflector 100 compared to the intensity distribution of the radio waves reflected by the comparative reflector 1, there are a plurality of peaks (11) located on both sides of the peak with the highest intensity (No. 11). ⁇ 10 and 12 ⁇ 19) width (width of angle ⁇ ) is narrow, but the strength of the radio waves is high. That is, by arranging the four reflectors 100R at a certain distance from each other like the reflector 100, multiple peaks (Nos. 1 to 10 and Nos. 12 to 19) located on both sides of the peak with the highest intensity (No. 11) can be obtained. The strength of radio waves is increasing.
  • the ratio between the RCS of the peak with the highest intensity (number 11) and the RCS of the peaks 10 and 12 on both sides is approximately 2 dB.
  • the RCS of the 10th and 12th peaks is approximately 25 dBm 2 , which is a radio wave intensity at a sufficient level for the receiving terminal to communicate.
  • the ratio between the RCS of the peaks 9 and 13, which are one step outside of the peak with the highest intensity (no. 11), and the RCS of the peak with the highest intensity (no. 11) is about 7 dB.
  • the RCS of peaks 9 and 13 is approximately 20 dBm 2 , which is a radio wave intensity at a sufficient level for a receiving terminal to communicate.
  • the radio wave intensity is at a sufficient level for the receiving terminal to communicate.
  • the radio field strength required for a terminal to communicate is approximately 20 dBm2 .
  • the ratio of the peak with the highest intensity to RCS is 3 dB or less on both neighboring peaks (peaks corresponding to No. 10 and 12), or peaks further outside thereof (peaks corresponding to No. 9 and 13). ), it was confirmed through simulation that the distance Dw between adjacent reflecting plates 100R is preferably 0.2 ⁇ L1 or more and 0.2 ⁇ L2 or more. Further, it was confirmed by simulation based on Huygens' principle that it is more preferable that the value is 1.2 ⁇ L1 or more and 1.2 ⁇ L2 or more.
  • the valley portion between adjacent peaks among peaks 1 to 19 is considered to be a null point.
  • the valley portion between adjacent peaks is the minimum value portion included in the characteristic shown by the solid line in FIG. If the receiving terminal exists in the direction of a certain angle of the null point, the receiving terminal cannot receive the radio waves reflected by the reflector 100.
  • the radio wave transmission system 10 of the embodiment uses, in addition to the peak with the highest intensity (No. 11), multiple peaks on both sides of the peak with the highest intensity (No. 11) to efficiently transmit the receiving terminal.
  • peaks having RCSs that can be received by the receiving terminal may be used. The search method will be described below with reference to FIGS. 15A and 15B.
  • 15A and 15B are diagrams illustrating an example of a method of searching for a receiving terminal in the radio wave transmission system 10.
  • the horizontal axis represents angle ⁇ (degrees)
  • the vertical axis represents RCS (dBm 2 ).
  • the characteristics indicated by solid lines, broken lines, and dashed-dotted lines are controlled by the control unit 5 of the radio wave transmission system 10 to turn on and off each cell 110 of the four reflecting plates 100R of the reflector 100.
  • the intensity distributions of the reflected waves shown by the solid line, the broken line, and the dashed-dotted line each have four peaks.
  • the RCS of the two center peaks among the four peaks are equal
  • the RCS of the two outer peaks are equal to each other.
  • the RCS is about 3 dB lower than the two central peaks.
  • the four peaks shown in FIGS. 15A and 15B have sufficient strength as radio waves received by the receiving terminal.
  • the set reflection direction is the center of the two central peaks.
  • the intensity distribution of the dashed line is shifted by one peak in the negative direction of the angle ⁇ ; , is shifted by one peak in the positive direction of the angle ⁇ .
  • the intensity distribution of the dashed line is shifted in the negative direction of the angle ⁇ by two peaks with respect to the intensity distribution of the solid line, and the intensity distribution of the dashed-dotted line is shifted from the intensity distribution of the solid line by two peaks in the negative direction of the angle ⁇ . , is shifted by two peaks in the positive direction of the angle ⁇ .
  • the intensity distributions shown by solid lines, broken lines, and dashed-dotted lines in FIGS. 15A and 15B are not simulation results but are shown as images, but the control unit 5 controls whether each cell 110 of the four reflectors 100R is turned on or off. This can be achieved by controlling the Therefore, by controlling the ON/OFF state of each cell 110 of the four reflectors 100R, the control unit 5 can scan the intensity distribution of the radio waves reflected by the reflector 100 in the direction of the angle ⁇ .
  • FIG. 15A for example, when the controller 5 is setting each cell 110 of the four reflectors 100R on and off so as to obtain the characteristic shown by the solid line, the valley part (null) of the characteristic shown by the solid line If the receiving terminal exists at point ), the receiving terminal cannot receive the radio waves reflected by the reflector 100.
  • the control unit 5 controls on and off of each cell 110 of the four reflectors 100R and shifts the intensity distribution shown by the solid line by one peak to the intensity distribution shown by the broken line or the dashed-dotted line, the intensity distribution shown by the solid line changes. At least one of the peaks indicated by the broken line or the dashed-dotted line overlaps the valley portion. By doing so, if the peak of the broken line or the dashed-dotted line overlaps the position of the receiving terminal, the receiving terminal can receive the radio wave reflected by the reflector 100. Note that this also applies to FIG. 15B.
  • the control unit 5 controls on and off of each cell 110 of the four reflectors 100R and scans the reflection angle of the reflector 100 to search for a receiving terminal. For example, a solid line intensity distribution is obtained when the control unit 5 sets the reflection angle of the reflector 100 to the first reflection angle, and when the control unit 5 sets the reflection angle of the reflector 100 to the second reflection angle. In this case, an intensity distribution of a dashed line or a dashed-dotted line is obtained. By switching the reflection angle of the reflector 100 between the first reflection angle and the second reflection angle, the set reflection direction changes.
  • the control unit 5 by scanning the reflection angle of the reflector 100 from the first reflection angle to the second reflection angle, the control unit 5 causes at least one of the peaks of the broken line or the dashed-dotted line to appear in the valley of the intensity distribution of the solid line. Overlap.
  • the radio wave transmission system 10 thus searches for a receiving terminal by scanning the reflection angle of the reflector 100 to the first reflection angle or the second reflection angle.
  • FIG. 16A is a diagram showing an example of a simulation result obtained by scanning the intensity distribution of radio waves reflected by the reflector 100.
  • FIG. 16B is a diagram showing an example of a simulation result obtained by scanning the intensity distribution of radio waves reflected by the comparative reflector 1.
  • the horizontal axis represents angle ⁇ (degrees)
  • the vertical axis represents RCS (dBm 2 ).
  • the simulation performed here is a simulation based on equations (3) and (5), and is a simulation based on Huygens' principle.
  • FIGS. 16A and 16B show intensity distributions overlaid when the reflection angles of reflector 100 and reflector 1 are scanned at 10 different reflection angles.
  • the RCS of the highest intensity peak was approximately 33 dBm2
  • the RCS of the second highest intensity peak (subpeak) was approximately 26 dBm2
  • the RCS of the highest intensity peak was approximately 34 dBm2
  • the RCS of the second highest intensity peak (subpeak) was approximately 22 dBm2 .
  • the control unit 5 scans the reflection angle of the reflector 100 by controlling ON and OFF of each cell 110 of the four reflection plates 100R, so that the reflection angle of the reflector 100 reaches the peak when the reflection angle is the first reflection angle.
  • a peak when the reflection angle of the reflector 100 is set to the second reflection angle can be placed in the valley between them.
  • the predetermined value of RCS is, for example, 26 dBm 2 as described using FIG. 16A.
  • the radio wave transmission system 10 includes a reflector 100 having a plurality of reflection plates 100R capable of scanning reflection angles, and a control unit 5 that scans reflection angles of the plurality of reflection plates 100R.
  • Each of the plurality of reflection plates 100R has a length L1 in the X direction and a length L2 in the Y direction, and the plurality of reflection plates 100R are two-dimensionally arranged along the X direction and the Y direction, Radio waves can be reflected at angles other than specular reflection, and the interval between adjacent reflectors 100R of at least some of the plurality of reflectors 100R is 0.2 ⁇ L1 or more in the X direction, or 0.2 ⁇ L1 or more in the Y direction. It is 0.2 ⁇ L2 or more.
  • the control unit 5 sets at least one of the plurality of peaks at a position between the plurality of peaks of the intensity of the radio waves reflected by the plurality of reflection plates 100R when the reflection angle is set to the first reflection angle.
  • the reflection angle is scanned to a second reflection angle so that the reflection angle is located.
  • an interval of 0.2 ⁇ L1 or more in the X direction and 0.2 ⁇ L2 or more in the Y direction is provided between at least some of the reflective plates 100R among the plurality of reflective plates 100R, so that the reflection
  • By scanning the reflection angle of the device 100 it is possible to widen the range of angles ⁇ for which RCS is equal to or greater than a predetermined value. Therefore, receiving terminals can be efficiently searched for with fewer scans.
  • the distance between adjacent reflectors is such that the distance between adjacent reflectors of at least some of the plurality of reflectors 100R is 0.5 ⁇ L1 or more in the X direction, and the distance between at least some of the reflectors is 0.5 ⁇ L1 or more in the X direction. It is preferable that the interval between adjacent ones is 0.5 ⁇ L2 or more in the Y direction. In such a case, a receiving terminal can be efficiently searched for with fewer scans in both the X direction and the Y direction.
  • the distance between adjacent reflectors should be 0.5 ⁇ L1 or more in the X direction and 0.5 ⁇ L2 or more in the Y direction for at least some of the reflectors. preferable. In this case, a receiving terminal can be efficiently searched for with a smaller number of scans in both the X direction and the Y direction using a relatively small number of reflectors.
  • the distance between adjacent reflectors 100R should be 0.5 ⁇ L1 or more in the X direction and 0.5 ⁇ L2 or more in the Y direction for all the reflectors 100R. More preferred. With a relatively small number of reflecting plates 100R, it is possible to efficiently search for a receiving terminal in both the X direction and the Y direction with a smaller number of scans.
  • each reflector 100R since the lengths L1 and L2 of each reflector 100R are 40 cm or less, it is possible to reduce the size and reliably add a phase change to the radio waves when reflecting them, and reflect them in the set reflection direction. It can reliably reflect waves.
  • Radio waves are in the millimeter wave band, when reflecting radio waves in frequency bands such as 5th generation mobile communication systems (5G) and Sub-6, radio wave transmission can efficiently search for receiving terminals.
  • System 10 can be provided.
  • each reflector 100R has a plurality of cells 110 that can change the phase of the radio wave when reflecting the radio wave, and in each reflector 100R, the plurality of cells 110 have a phase change that changes the phase of the radio wave. Control the amount electrically. Therefore, the amount of phase change can be changed to any value among continuous values, and the amount of phase change can be controlled in a multivalued manner.
  • each reflector 100R since ten or more cells 110 in each reflector 100R are arranged in the X direction and ten or more in the Y direction, it is possible to reliably add a phase change amount to the radio wave when reflecting it.
  • the reflected wave can be reliably reflected in the set reflection direction.
  • the length of the cell 110 in the X direction and the length of the cell 110 in the Y direction are both 2 ⁇ or less.
  • the amount of phase change can be reliably added to the radio waves, and the reflected waves can be reliably reflected in the set reflection direction.
  • the cell 110 has a phase shifter that can adjust the amount of phase change by electrical control, and the phase shifter is made of liquid crystal or ferroelectric material. Therefore, using a phase shifter made of liquid crystal or ferroelectric material, the amount of phase change can be changed to any continuous value, making it possible to control the amount of phase change in a multivalued manner. It is.
  • the phase change amount by which each cell 110 of each reflector 100R changes the phase of the radio wave is a binary value of the first value or the second value
  • the plurality of reflectors 100 By setting the phase change amount of 110 to the first value or the second value, it is possible to reflect the radio waves at a plurality of reflection angles. Therefore, by controlling the amount of phase change in a binary manner, the reflection angle can be adjusted to an angle other than specular reflection.
  • the reflection angle can be adjusted to reflect the mirror surface. Can be adjusted to angles other than reflection.
  • the cell 110 includes a resonant element 111, a resonant element 112, and a switching element that can switch the resonant frequency of the resonant element 112 to a first resonant frequency or a second resonant frequency by electrical control.
  • a switching element that can switch the resonant frequency of the resonant element 112 to a first resonant frequency or a second resonant frequency by electrical control.
  • a PIN diode, MEMS switch, varactor, or transistor is a PIN diode, MEMS switch, varactor, or transistor. Therefore, the amount of phase change can be reliably controlled in a binary manner, and the reflected wave can be reliably reflected in the set reflection direction while reducing unnecessary reflections.
  • Control unit 10 Radio wave transmission system 100 Reflector 100R Reflector 110 Cell 111 Resonant element 112 Resonant element 112A, 112B Linear element 112C PIN diode

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Abstract

Un système de transmission d'ondes radio comprend un réflecteur qui comporte une pluralité de plaques de réflexion, dont les angles de réflexion peuvent être balayés, et une unité de commande qui balaie les angles de réflexion de la pluralité de plaques de réflexion. Chaque plaque de la pluralité de plaques de réflexion présente une première longueur (L1) dans une première direction axiale, et une seconde longueur (L2) dans une seconde direction axiale. La pluralité de plaques de réflexion sont agencées de manière bidimensionnelle le long de la première direction axiale et de la seconde direction axiale, et peuvent réfléchir des ondes radio à des angles autres que celui de la réflexion spéculaire. Parmi au moins une partie de la pluralité de plaques de réflexion, l'intervalle entre des plaques voisines est de 0,2×L1 ou plus dans la première direction axiale, ou de 0,2×L2 ou plus dans la seconde direction axiale. L'unité de commande balaye les angles de réflexion à un second angle de réflexion, de telle sorte qu'au moins un pic d'une pluralité de pics de l'intensité d'ondes radio réfléchies par la pluralité de plaques de réflexion est situé à un emplacement situé entre ladite pluralité de pics lorsque les angles de réflexion sont réglés à un premier angle de réflexion.
PCT/JP2023/017440 2022-05-20 2023-05-09 Système de transmission d'ondes radio et procédé de recherche de terminal de réception WO2023223895A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013115756A (ja) * 2011-11-30 2013-06-10 Ntt Docomo Inc リフレクトアレー
JP2021175054A (ja) * 2020-04-22 2021-11-01 Kddi株式会社 メタサーフェス反射板アレイ
WO2022092029A1 (fr) * 2020-10-30 2022-05-05 電気興業株式会社 Réseau réflecteur variable et procédé de conception de réseau réflecteur variable
WO2022244676A1 (fr) * 2021-05-17 2022-11-24 株式会社ジャパンディスプレイ Plaque de réflexion d'ondes radio et dispositif de réflexion d'ondes radio

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013115756A (ja) * 2011-11-30 2013-06-10 Ntt Docomo Inc リフレクトアレー
JP2021175054A (ja) * 2020-04-22 2021-11-01 Kddi株式会社 メタサーフェス反射板アレイ
WO2022092029A1 (fr) * 2020-10-30 2022-05-05 電気興業株式会社 Réseau réflecteur variable et procédé de conception de réseau réflecteur variable
WO2022244676A1 (fr) * 2021-05-17 2022-11-24 株式会社ジャパンディスプレイ Plaque de réflexion d'ondes radio et dispositif de réflexion d'ondes radio

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