The present invention relates to a liquid crystal antenna and a method for manufacturing a liquid crystal antenna.
Patent Literatures 1 to 4 describe liquid crystal antennas each using a liquid crystal layer.
A liquid crystal antenna has been manufactured at a relatively low cost similarly to a liquid crystal display since a technique used for the liquid crystal display can be utilized. Further, a light and thin liquid crystal antenna has been manufactured.
However, the liquid crystal antenna has a planar shape, and four planar antennas each covering 90° are required in order to obtain an antenna covering 360° such as a front hole. Specifically, it is possible to obtain the antenna covering 360° for example, by arranging four planar antennas on four side surfaces of a rectangular tube. In such an arrangement, a radio wave transmitted and received near a corner portion of the rectangular tube becomes weak. Further, each of the antennas is a multi-element antenna, and thus, a weight increases, and cost increases. Furthermore, a large space is required because the antennas need to be installed so as not to collide with each other.
In view of the above-described problems, an object of the present disclosure is to provide a liquid crystal antenna capable of adapting a transmission/reception direction to 360° in a horizontal direction and reducing a size, a weight, and cost, and a method for manufacturing the liquid crystal antenna.
A liquid crystal antenna according to an example embodiment includes a curved liquid crystal panel and is a phased array type, and the liquid crystal panel includes: a liquid crystal layer; and a plurality of antenna elements configured to transmit and receive signals having phases modulated by variable dielectric constant elements including the liquid crystal layer.
A method for manufacturing a liquid crystal antenna according to an example embodiment is a method for manufacturing a liquid crystal antenna of a phased array type including: a step of forming a liquid crystal panel having a planar shape and including a liquid crystal layer and a plurality of antenna elements configured to transmit and receive signals having phases modulated by a variable dielectric constant element including the liquid crystal layer; and a step of curving the liquid crystal panel.
According to one example embodiment, there are provided the liquid crystal antenna, capable of adapting the transmission/reception direction to 360° in the horizontal direction and reducing the size, the weight, and the cost, and the method for manufacturing the liquid crystal antenna.
Hereinafter, example embodiments will be described with reference to the drawings. For clarity of description, omission and simplification are made as appropriate in the following description and drawings. Further, in each drawing, the same elements are denoted by the same reference signs, and redundant description is omitted as necessary.
A liquid crystal antenna according to a first example embodiment will be described. First, <Configuration of Liquid Crystal Antenna> will be described. Thereafter, <Configuration of Liquid Crystal Panel> will be described, and <Method for Manufacturing Liquid Crystal Antenna> will be described after <Beam Emission Direction> and <Beam Formation> will be described.
<Configuration of Liquid Crystal Antenna>
For convenience of description of the liquid crystal antenna 1, an XYZ orthogonal coordinate axis system is introduced. A center-axis direction of the cylindrical liquid crystal panel 100 is defined as a Z-axis direction, and two directions in a plane orthogonal to the Z-axis are defined as an X-axis direction and a Y-axis direction. For example, the Z-axis direction is defined as a vertical direction, and the XY plane is defined as a horizontal plane. Further, a +Z-axis direction is defined as upward, and a −Z-axis direction is defined as downward. Note that the vertical direction, the horizontal plane, upward, and downward are directions for convenience of description of the liquid crystal antenna 1, and do not actually indicate directions in which the liquid crystal antenna 1 is used.
The liquid crystal panel 100 may have a junction 102 along the Z-axis direction on a side surface 101 of the cylindrical shape. For example, the liquid crystal panel 100 may be formed by curving a horizontally long planar panel, which is a base of the liquid crystal panel 100, around a central axis that extends in the Z-axis direction and connecting short sides at the junction 102. For example, it is possible to form the liquid crystal panel 100 that can be deformed to be curved by using a display forming technique including a flexible liquid crystal panel. In the case of liquid crystal, deformation of a molecular sequence due to bending affects a display, and thus, it is difficult to make the liquid crystal flexible to the same extent as organic electro luminescence (EL), but the liquid crystal can be curved to some extent. The liquid crystal panel 100 can be used in the case of being fixed even if being deformed to be curved.
The side surface 101 of the cylindrical liquid crystal panel 100 is also referred to as an outer surface 103. The liquid crystal antenna 1 is formed such that a radio wave is emitted in a normal direction from the outer surface 103 of the liquid crystal panel 100.
The liquid crystal antenna 1 has a structure in which a member that supplies a signal to the liquid crystal panel 100 is combined in addition to the liquid crystal panel 100. For example, the liquid crystal antenna 1 may include a top plate 310, a bottom plate 320, a strut 330, a signal distributor 340, and a signal line 350 in addition to the liquid crystal panel 100.
The top plate 310 has a disk shape, and is arranged as a lid on an upper opening of the cylindrical liquid crystal panel 100. The top plate 310 is omitted in
The signal distributor 340 is arranged, for example, on the bottom plate 320. Note that the signal distributor 340 may be arranged on the liquid crystal panel 100. The signal distributor 340 and the liquid crystal panel 100 are connected by the signal line 350. The signal distributor 340 supplies a signal to the liquid crystal panel 100 via the signal line 350. When a thin film transistor (TFT) is used for the liquid crystal panel 100, the signal distributor 340 supplies a signal for driving the TFT as well as the signal supplied to the liquid crystal panel 100.
<Configuration of Liquid Crystal Panel>
As illustrated in
Therefore, the liquid crystal panel 100 includes the spiral wiring 127 and the ground wiring 123 as variable dielectric constant elements, and includes the patch antenna element 120 as an antenna element. In this case, the dielectric constant of the liquid crystal layer 110 is changed by applying the bias voltage between the spiral wiring 127 and the ground wiring 123. The plurality of patch antenna elements 120 transmit and receive signals having phases modulated by the variable dielectric constant elements including the liquid crystal layer 110. The liquid crystal antenna 1 is a phased array type antenna. For example, the variable dielectric constant element such as an element that applies a bias voltage between the spiral wiring 127 and the ground wiring 123 may include a TFT. As a result, a response speed of the liquid crystal layer 110 can be improved. Note that a configuration including the DC blocking structure 121 and the spiral wiring 127 as illustrated in
<Emission Direction of Beam>
If steering in the Z-axis direction can sufficiently function, a region to be covered can be set to a wide range even in a plane parallel to the Z-axis direction. However, downward steering is sometimes sufficient, for example, in a case where the liquid crystal antenna 1 is used as a base station of a mobile terminal.
As illustrated in
<Formation of Beam>
The liquid crystal panel 100 may have a cylindrical shape by arraying and connecting the plurality of divided rows 105a to 105e along the circumference of the liquid crystal panel 100. In this case, one beam BM may be emitted from one divided row 105. As a result, an emission direction of the beam BM emitted from each of the divided rows 105 can be made different from an emission direction from the adjacent divided row 105. Therefore, the directivity of the radio wave transmitted and received by each divided row 105 can be improved.
Further, a beam BM1 may be formed by a plurality of the divided rows 105a to 105c, and a beam BM2 may be formed by a plurality of the divided rows 105b to 105d or the like. With such a configuration, it is possible to perform transmission and reception in a wider range than a range in which transmission and reception can be performed by the single divided row 105. For example, in a case where the liquid crystal antenna 1 is a base station of a mobile terminal, a person who holds the mobile terminal moves with respect to the liquid crystal antenna 1. At this time, the divided rows 105 communicating with the mobile terminal can be smoothly shifted over the divided rows 105a to 105c while maintaining a communication state so as to follow the movement of the mobile terminal.
Further, when the plurality of divided rows 105a to 105e are used for one signal, an antenna area can be increased so that the sensitivity can be improved.
<Method for Manufacturing Liquid Crystal Antenna>
Next, a method for manufacturing the liquid crystal antenna 1 will be described.
Next, as illustrated in
Next, the short sides of the liquid crystal panel 100 may be connected at the junction 102 to form the liquid crystal panel PNL into a cylindrical shape by connecting as illustrated in
Note that when forming the liquid crystal panel PNL into the cylindrical shape, the liquid crystal panel PNL may be formed to include a plurality of the divided rows 105 and formed into the cylindrical shape by connecting the plurality of divided rows 105. Further, when forming the liquid crystal panel PNL into the cylindrical shape, an emission direction of the beam BM emitted from each of the divided rows 105 may be made different from an emission direction from the adjacent divided row 105.
In
Note that, in a case where the liquid crystal antenna 1 is mounted on the existing utility pole 401 and the existing post of the street lamp 402, it is difficult to insert and mount the liquid crystal antenna 1 from distal ends thereof. Thus, it is desirable to attach perform mounting using the divided rows 105 as illustrated in
Next, effects of the present example embodiment will be described. The liquid crystal antenna 1 of the present example embodiment includes the curved liquid crystal panel 100. Thus, the transmission/reception direction of the radio wave can be adapted to 360° in the horizontal direction. For example, since the substantially normal direction of the curved liquid crystal panel 100 is set as the emission direction of the beam BM, it is possible to cover 360° in the horizontal direction. Thus, a change in a steering direction of each of the beams BM can be designed to be small. Further, a decrease in the amount of the change in the steering direction contributes to an increase in a speed of an operation.
Further, since a liquid crystal display formation technique is used, the liquid crystal antenna 1 is small, thin, and lightweight, and thus, the cost can be reduced. It is easy to install the liquid crystal antenna 1 to the utility pole 401 and the post of the street lamp 402 or the like by taking advantages of the small size, the thin size, and the light weight. Note that the liquid crystal panel 100 has been described to have the cylindrical shape, but the shape is not necessarily limited to the cylindrical shape. For example, when being mounted to a vehicle, the liquid crystal antenna 1 may be curved so as to match a curved body of the vehicle. The liquid crystal antenna 1 can be formed in a flexible shape, and thus, can be formed in any curved surface as necessary.
Next, a liquid crystal antenna according to a second example embodiment will be described.
As illustrated in
The metasurface layer 230 has a plurality of opening portions 220 penetrating from the outer surface 201 to the liquid crystal layer 210. The liquid crystal panel 200 has the metasurface layer 230 as a variable dielectric constant element, and has the opening portions 220 formed in the metasurface layer 230 as antenna elements. Then, the liquid crystal panel 200 changes a resonance condition of the liquid crystal layer 210 and the metasurface layer 230, and causes a radio wave from the traveling wave tube 240 to leak from the opening portion 220 as a signal. In this manner, the liquid crystal panel 200 transmits and receives the signal whose phase has been modulated by the variable dielectric constant element including the liquid crystal layer 210.
The liquid crystal panel 200 may have a plurality of divided rows including portions of the liquid crystal layer 210 and the metasurface layer 230 on each of the traveling wave tubes 240. As a result, an emission direction of a beam emitted from each of the divided rows may be made different from an emission direction from an adjacent divided row similarly to the first example embodiment. Further, in a case where liquid crystal antenna 2 is used as a base station of a mobile terminal, the plurality of divided rows communicating with the mobile terminal may sequentially be shifted to follow movement of the mobile terminal.
According to the present example embodiment, the liquid crystal panel 200 including the metasurface layer 230 can also be curved, and a transmission/reception direction of the radio wave can cover 360° in the horizontal direction. Other configurations and effects are included in the description of the first example embodiment.
Note that the present invention is not limited to the above example embodiments, and can be appropriately changed without departing from the scope of the present invention. For example, a combination of the configurations of the first and second example embodiments is also included in the technical scope of the present embodiment.
Some or all of the above-described example embodiments may be described as in the following Supplementary Notes, but are not limited to the following Supplementary Notes.
(Supplementary Note 1)
A liquid crystal antenna of a phased array type, including a curved liquid crystal panel,
(Supplementary Note 2)
The liquid crystal antenna according to Supplementary Note 1, in which the liquid crystal layer is curved.
(Supplementary Note 3)
The liquid crystal antenna according to Supplementary Note 1 or 2, in which the liquid crystal panel has a cylindrical shape.
(Supplementary Note 4)
The liquid crystal antenna according to Supplementary Note 3, in which
(Supplementary Note 5)
The liquid crystal antenna according to Supplementary Note 4, in which an emission direction of a beam emitted from each of the divided rows is different from an emission direction from the divided row that is adjacent.
(Supplementary Note 6)
The liquid crystal antenna according to any one of Supplementary Notes 1 to 5, in which an emission direction of a beam of a radio wave emitted from the liquid crystal panel includes a substantially normal direction of an outer surface of the liquid crystal panel.
(Supplementary Note 7)
The liquid crystal antenna according to any one of Supplementary Notes 1 to 6, in which
(Supplementary Note 8)
The liquid crystal antenna according to any one of Supplementary Notes 1 to 6, in which
(Supplementary Note 9)
The liquid crystal antenna according to any one of Supplementary Notes 1 to 8, in which the variable dielectric constant element includes a thin film transistor.
(Supplementary Note 10)
The liquid crystal antenna according to any one of Supplementary Notes 1 to 9, in which the liquid crystal panel is arranged around at least any of a utility pole, a telegraph pole, a street lamp, and a signal light.
(Supplementary Note 11)
A method for manufacturing a liquid crystal antenna of a phased array type, the method including:
(Supplementary Note 12)
The method for manufacturing a liquid crystal antenna according to Supplementary Note 11, in which the liquid crystal layer is curved in the step of curving the liquid crystal panel.
(Supplementary Note 13)
The method for manufacturing a liquid crystal antenna according to Supplementary Note 11 or 12, further including a step of forming the liquid crystal panel into a cylindrical shape.
(Supplementary Note 14)
The method for manufacturing a liquid crystal antenna according to Supplementary Note 13, in which the liquid crystal panel is formed to include a plurality of divided rows and is formed into the cylindrical shape by connecting the plurality of divided rows in the step of forming the liquid crystal panel into the cylindrical shape.
(Supplementary Note 15)
The method for manufacturing a liquid crystal antenna according to Supplementary Note 14, in which an emission direction of a beam emitted from each of the divided rows is made different from an emission direction from the divided row that is adjacent in the step of forming the liquid crystal panel into the cylindrical shape.
(Supplementary Note 16)
The method for manufacturing a liquid crystal antenna according to any one of Supplementary Notes 11 to 15, in which an emission direction of a beam of a radio wave emitted from the liquid crystal panel is set to include a substantially normal direction of an outer surface of the liquid crystal panel in the step of curving the liquid crystal panel.
(Supplementary Note 17)
The method for manufacturing a liquid crystal antenna according to any one of Supplementary Notes 11 to 16, in which
(Supplementary Note 18)
The method for manufacturing a liquid crystal antenna according to any one of Supplementary Notes 11 to 16, in which
(Supplementary Note 19)
The method for manufacturing a liquid crystal antenna according to any one of Supplementary Notes 11 to 18, in which the variable dielectric constant element is formed to include a thin film transistor in the step of forming the liquid crystal panel.
(Supplementary Note 20)
The method for manufacturing a liquid crystal antenna according to Supplementary Note 14, in which the plurality of divided rows are connected around at least one of a utility pole, a telegraph pole, a street lamp, and a signal light to form the cylindrical shape in the step of forming the liquid crystal panel into the cylindrical shape.
This application claims priority based on Japanese Patent Application No. 2021-057212 filed on Mar. 30, 2021, the entire disclosure of which is incorporated herein.
Number | Date | Country | Kind |
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2021-057212 | Mar 2021 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2021/045690 | 12/10/2021 | WO |