Resonance structure and radio wave control plate

Abstract

This resonance structure is included in a radio wave control plate, and comprises: a resonance conductor disposed on a first surface; and a ground conductor disposed on a second surface separated from the first surface in a first direction. The resonance conductor comprises a first conductor and a second conductor disposed apart from the first conductor. The ground conductor has at least one opening when viewed in plan from the first direction.

Description

Resonant structure and radio wave control plate

[0001] This disclosure relates to a resonant structure and an electromagnetic wave control plate.

[0002] Patent Document 1 discloses a radio wave control plate that transmits or reflects radio waves, which includes a plurality of unit structures using metasurfaces.

[0003] Japanese Patent Publication No. 2022-165403

[0004] The resonant structure of the present disclosure is a resonant structure included in a radio wave control plate, comprising a resonant conductor disposed on a first surface and a ground conductor disposed on a second surface located away from the first surface in a first direction, wherein the resonant conductor comprises a first conductor and a second conductor disposed spaced apart from the first conductor, and the ground conductor has at least one opening when viewed from the first direction in a plan view.

[0005] The radio wave control plate of this disclosure includes the resonant structure of this disclosure.

[0006] Figure 1 is a diagram illustrating the outline of a radio wave control board. Figure 2 is a diagram illustrating an example configuration of a radio wave control board according to a comparative example. Figure 3 is a diagram illustrating an example configuration of a unit structure according to a comparative example. Figure 4 is a diagram illustrating an example configuration of a unit structure according to the first embodiment. Figure 5 is a diagram illustrating an example configuration of a resonant structure according to the first embodiment. Figure 6 is a diagram illustrating an example configuration of the first electrode and the second electrode according to the first embodiment. Figure 7 is a diagram illustrating the positional relationship between the first electrode and the second electrode of the resonant structure according to the first embodiment. Figure 8 is a diagram illustrating the simulation results of the characteristics of the resonant structure according to the first embodiment. Figure 9 is a diagram illustrating the positional relationship between the first electrode and the second electrode of the resonant structure according to a comparative example of the first embodiment. Figure 10 is a diagram illustrating the simulation results of the characteristics of the resonant structure according to a comparative example of the first embodiment. Figure 11 is a diagram illustrating an example configuration of the first electrode and the second electrode according to the second embodiment. Figure 12 is a diagram illustrating the positional relationship between the first electrode and the second electrode according to the second embodiment. Figure 13 is a diagram illustrating the simulation results of the characteristics of the resonant structure according to the second embodiment. Figure 14 is a diagram illustrating the positional relationship between the first electrode and the second electrode according to a comparative example of the second embodiment. Figure 15 shows the simulation results of the characteristics of a resonant structure according to a comparative example of the second embodiment. Figure 16 shows an example of the configuration of the first and second electrodes according to the third embodiment. Figure 17 shows the positional relationship between the first and second electrodes according to the third embodiment. Figure 18 shows the simulation results of the characteristics of a resonant structure according to the third embodiment. Figure 19 shows the positional relationship between the first and second electrodes according to a comparative example of the third embodiment. Figure 20 shows the simulation results of the characteristics of a resonant structure according to a comparative example of the third embodiment. Figure 21 shows an example of the configuration of a unit structure according to another embodiment.

[0007] Embodiments of the present invention will be described in detail below with reference to the attached drawings. However, the present invention is not limited by these embodiments, and in the following embodiments, the same parts are denoted by the same reference numerals to omit redundant explanations.

[0008] [Overview] (Radio Control Panel) The overview of the radio control panel will be explained using Figure 1. Figure 1 is a diagram illustrating the overview of the radio control panel.

[0009] The radio wave control plate 1 is configured to control the direction of propagation of incident radio waves. For example, when the radio wave control plate 1 receives radio waves transmitted by a base station, it is configured to reflect or refract those radio waves at a predetermined angle. The radio wave control plate 1 may be composed of, for example, a metamaterial that changes the phase of the incident wave. The radio wave control plate 1 may be capable of controlling not only one of the directions of reflection and / or transmission (refractory) of radio waves, but both. In this disclosure, reflection and refraction together are referred to as emission.

[0010] As shown in Figure 1, the radio wave control board 1 may include, for example, a substrate 2, and unit structures 10a, 10b, 10c, and 10d. When it is not necessary to distinguish between unit structures 10a and 10d, they are collectively referred to as unit structure 10. Unit structure 10 is also called a metasurface element.

[0011] The unit structures 10a, 10b, 10c, and 10d can be formed on a substrate 2. The substrate 2 may be, for example, a dielectric substrate made of a dielectric material. The substrate 2 may, for example, have a rectangular shape, but is not limited thereto. The unit structures 10a, 10b, 10c, and 10d can be arranged in two dimensions.

[0012] In the radio wave control panel 1, multiple unit structures 10a are arranged along the X-axis on each tier. On the tier above where unit structures 10a are located, multiple unit structures 10b are arranged along the X-axis. On the tier above where unit structures 10b are located, multiple unit structures 10c are arranged along the X-axis. On the tier above where unit structures 10c are located, multiple unit structures 10d are arranged along the X-axis. In the example shown in Figure 1, unit structures 10a, 10b, 10c, and 10d are arranged periodically along the Y-axis. Note that each unit structure does not necessarily have to be arranged parallel to the X-axis and Y-axis directions. For example, the direction in which the multiple unit structures 10a are arranged does not have to intersect perpendicularly with the direction in which unit structures 10a, 10b, 10c, and 10d are arranged.

[0013] By making the properties of each unit structure 10a to 10d different, the amount of phase change (the difference between the phase of the incident radio wave and the phase of the emitted radio wave) can be made different for each unit structure 10a to 10d. By making the properties of each unit structure 10a to 10d different so that the amount of phase change increases (or decreases) sequentially, the radio wave control plate 1 has a gradient of phase change. The radio wave control plate 1 can reflect and / or refract the incident radio wave in a predetermined direction due to the gradient of phase change. In Figure 1, the shapes of the unit structures 10a to 10d are rectangular, but the shape of the unit structures is not limited to rectangles.

[0014] [Comparative Example] Using Figures 2 and 3, we will explain the configuration example of a radio wave control board and a unit structure according to the comparative example. Figure 2 is a diagram showing the configuration example of a radio wave control board according to the comparative example. Figure 3 is a diagram showing the configuration example of a unit structure according to the comparative example.

[0015] As shown in Figure 2, the radio wave control plate 1 has a plurality of unit structures 10-1. The unit structures 10-1 are arranged periodically in the XY plane. The radio wave control plate 1 is configured to refract radio waves W1 arriving from the -Z axis direction in a predetermined direction and emit transmitted waves W2.

[0016] As shown in Figures 2 and 3, the unit structure 10-1 comprises a first electrode 11, a second electrode 12, and a liquid crystal layer 13.

[0017] The first electrode 11 is located on the upper surface of the unit structure 10-1. The upper surface of the unit structure 10-1 is also called the first surface. The first electrode 11 is made of a conductor. The first electrode 11 is a resonant conductor that functions, for example, as a λ / 2 resonator. λ is the effective wavelength of the radio waves transmitted or reflected by the radio wave control plate 1.

[0018] The second electrode 12 is located on the lower surface of the unit structure 10-1, which is separated from the first electrode 11 in the Z-axis direction. The Z-axis direction is also called the first direction. The lower surface of the unit structure 10-1 is also called the second surface. The second electrode 12 is made of a conductor. The second electrode 12 is a ground conductor.

[0019] The liquid crystal layer 13 is positioned between the first electrode 11 and the second electrode 12. The liquid crystal layer 13 extends in the XY plane. When a voltage V1 is applied between the first electrode 11 and the second electrode 12, the orientation of the liquid crystal molecules 14 contained in the liquid crystal layer 13 changes according to the magnitude of the voltage V1. As the orientation of the liquid crystal molecules 14 changes, the capacitance value of the unit structure 10-1 changes. By adjusting the capacitance value of the unit structure 10-1, the refraction direction or reflection direction of radio waves can be changed.

[0020] Here, the range in which the orientation state of the liquid crystal molecules 14 can be controlled is the region where the first electrode 11 and the second electrode 12 overlap, and the region where the edge effect is present. Therefore, the range in which the orientation state of the liquid crystal molecules 14 can be controlled is narrow, and the amount of frequency change is small. Therefore, this disclosure provides a structure that can increase the amount of frequency change by widening the region in which the edge effect is present.

[0021] [First Embodiment] An example of the configuration of a unit structure according to the first embodiment will be described using Figures 4 and 5. Figure 4 is a diagram showing an example of the configuration of a unit structure according to the first embodiment. Figure 5 is a diagram showing an example of the configuration of a resonant structure according to the first embodiment.

[0022] As shown in Figure 4, the unit structure 10 according to the first embodiment includes a resonant structure 100-1 and a resonant structure 100-2. When it is not necessary to distinguish between the resonant structure 100-1 and the resonant structure 100-2, they are collectively referred to as the resonant structure 100. In the unit structure 10, the resonant structure 100-1 and the resonant structure 100-2 are stacked along the Z axis. In the radio wave control plate 1 of the first embodiment, the unit structure 10 including the resonant structure 100-1 and the resonant structure 100-2 is arranged two-dimensionally on the XY plane.

[0023] As shown in Figures 4 and 5, the resonant structure 100 comprises a first electrode 11, a second electrode 12, a liquid crystal layer 13, a first substrate 15, and a second substrate 16.

[0024] The first substrate 15 and the second substrate 16 are dielectric substrates. The first substrate 15 and the second substrate 16 are, for example, glass substrates, but are not limited to these.

[0025] The first electrode 11 is formed on one surface of the first substrate 15. The first electrode 11 extends in the XY plane.

[0026] The second electrode 12 is formed on one surface of the second substrate 16. The second electrode 12 extends in the XY plane. The first electrode 11 and the second electrode 12 face each other.

[0027] In the resonant structure 100-1, an adhesive layer 17-1 is formed on the other surface of the second substrate 16. In the resonant structure 100-2, an adhesive layer 17-2 is formed on the other surface of the second substrate 16. The adhesive layers 17-1 and 17-2 are, for example, OCA (Optically Clear Adhesive), but are not limited to this. An adjustment conductor 18 for adjusting the coupling between the resonant structure 100-1 and the resonant structure 100-2 is arranged between the adhesive layers 17-1 and 17-2.

[0028] In other words, in the unit structure 10, the resonant structure 100-1 and the resonant structure 100-2 are stacked in the Z-axis direction via adhesive layers 17-1, 17-2, and 18. Note that if the 18 is formed directly on the second substrate, either or both of the adhesive layers 17-1 and 17-2 may be omitted.

[0029] (Configuration Example of First Electrode and Second Electrode) A configuration example of the first electrode and the second electrode according to the first embodiment will be described with reference to FIG. 6. FIG. 6 is a diagram illustrating a configuration example of the first electrode and the second electrode according to the first embodiment.

[0030] FIG. 6(a) is a diagram illustrating a configuration example of the first electrode 11. The first electrode 11 includes a first conductor 21, a second conductor 22a, a second conductor 22b, a second conductor 22c, and a second conductor 22d.

[0031] The first conductor 21 is formed in a rectangular shape. The first conductor 21 is, for example, a patch conductor. The first electrode 11 is not the ground conductor (reference conductor) of the resonant structure 100. The first electrode 11 is a conductor (resonant conductor) that functions as a resonator.

[0032] The second conductor 22a is an L-shaped conductor formed at a position separated by a predetermined distance from the first vertex of the first conductor 21. For example, the second conductor 22a is formed at a position separated from the first vertex of the first conductor 21 by a distance shorter than the effective wavelength of an electromagnetic wave propagating through the first substrate 15 or the second substrate 16.

[0033] The second conductor 22b is an L-shaped conductor formed at a position separated by a predetermined distance from the second vertex of the first conductor 21. For example, the second conductor 22b is formed at a position separated from the second vertex of the first conductor 21 by a distance shorter than the effective wavelength of an electromagnetic wave propagating through the first substrate 15 or the second substrate 16.

[0034] The second conductor 22c is an L-shaped conductor formed at a position separated by a predetermined distance from the third vertex of the first conductor 21. For example, the second conductor 22c is formed at a position separated from the third vertex of the first conductor 21 by a distance shorter than the effective wavelength of an electromagnetic wave propagating through the first substrate 15 or the second substrate 16.

[0035] The second conductor 22d is an L-shaped conductor formed at a position separated by a predetermined distance from the fourth vertex of the first conductor 21. The second conductor 22d is formed at a position separated from the fourth vertex of the first conductor 21 by a distance shorter than the effective wavelength of an electromagnetic wave propagating through the first substrate 15 or the second substrate 16.

[0036] The second conductors 22a to 22d are formed to have four-fold rotational symmetry when viewed from the Z direction.

[0037] FIG. 6(b) is a diagram showing a configuration example of the second electrode 12. An opening 31 is formed in the second electrode 12. The opening 31 has, for example, a cross shape. The opening 31 is formed such that the widths of a tip end portion 31a, a tip end portion 31b, a tip end portion 31c, and a tip end portion 31d are wider than the widths of other portions.

[0038] By forming the first electrode 11 and the second electrode 12 as shown in FIGS. 6(a) and 6(b) respectively, when the resonant structure 100 is viewed in plan from the Z direction, the overlapping area between the first electrode 11 and the second electrode can be increased.

[0039] [First Embodiment] The positional relationship between the first electrode and the second electrode of the resonant structure according to the first embodiment will be described with reference to FIG. 7. FIG. 7 is a diagram for explaining the positional relationship between the first electrode and the second electrode of the resonant structure according to the first embodiment.

[0040] An overlapping region 51, an overlapping region 52, an overlapping region 53, and an overlapping region 54 are regions where the first conductor 21 of the first electrode 11 and the second electrode 12 overlap each other when viewed from the Z direction.

[0041] An overlapping region 61, an overlapping region 62, an overlapping region 63, and an overlapping region 64 are respectively regions where the second conductors 22a to 22d of the first electrode 11 overlap when viewed from the Z direction.

[0042] FIG. 8 is a diagram showing simulation results of characteristics of the resonant structure according to the first embodiment. In FIG. 8, the upper row shows simulation results in a state where no voltage is applied to the liquid crystal layer 13, and the lower row shows simulation results in a state where a voltage is applied to the liquid crystal layer 13.

[0043] In a state where no voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ is 5.07, the Q value is 137, and the eigenfrequency is 19.1 [GHz].

[0044] In a state where a voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒThe frequency is 3.9, the Q value is 142, and the eigenvalue is 20.2 [GHz].

[0045] In this simulation, the change in the normalized frequency Δf / f when comparing the state in which a voltage is applied to the liquid crystal layer 13 with the state in which no voltage is applied to the liquid crystal layer 13 is normalized. ０ Therefore, 1 - (19.1 / 20.2) ≈ 0.054.

[0046] Using Figure 9, the positional relationship between the first electrode and the second electrode of the resonant structure according to the comparative example of the first embodiment will be explained. Figure 9 is a diagram for explaining the positional relationship between the first electrode and the second electrode of the resonant structure according to the comparative example of the first embodiment.

[0047] The first electrode 11a according to the comparative example of the first embodiment differs from the first electrode 11 according to the first embodiment in that it does not include the second conductors 22a to 22d.

[0048] The second electrode 12a in the comparative example of the first embodiment has an opening 41. The opening 41 differs from the opening 31 formed in the second electrode 12 according to the first embodiment in that the width of the tip portion is the same as the width of the other portion.

[0049] The superimposed regions 51, 52, 53, and 54 are the regions where the first electrode 11a and the second electrode 12a overlap when viewed from the Z direction. In other words, compared to the comparative example of the first embodiment, the area of ​​the region where the first electrode 11 and the second electrode 12 overlap when viewed from the Z direction is wider in the first embodiment by the area from the second conductor 22a to the second conductor 22d.

[0050] Figure 10 shows the simulation results of the characteristics of the resonant structure according to a comparative example of the first embodiment. In Figure 10, the upper section shows the simulation results when no voltage is applied to the liquid crystal layer 13, and the lower section shows the simulation results when a voltage is applied to the liquid crystal layer 13.

[0051] When no voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The coefficient of vibration is 5.07, the Q value is 168, and the eigenvalue (resonant frequency) is 25.3 [GHz].

[0052] In a state where a voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ is 3.9, the Q value is 170, and the eigenfrequency is 25.9 [GHz].

[0053] In this simulation, when comparing the state where a voltage is applied to the liquid crystal layer 13 and the state where no voltage is applied to the liquid crystal layer 13, the amount of change Δf / f in the normalized frequency obtained by normalizing the resonance frequency ０ is 1-(25.3 / 25.9)≈0.023.

[0054] That is, in the first embodiment, compared with the comparative example of the first embodiment, Δf / f ０ increases from 0.023 to 0.054, which is more than double. This is because, in the first embodiment, by adding the second conductors 22a to 22d, the overlapping area between the first electrode 11 and the second electrode 12 becomes wider compared to the comparative example of the first embodiment, so that the controllable range of the orientation of liquid crystal molecules in the liquid crystal layer 13 is expanded. The detailed reason why Δf / f ０ increases is as follows. Since the controllable range of the orientation of liquid crystal molecules in the liquid crystal layer 13 is expanded, the amount of change in the spatial distribution of the relative dielectric constant of the liquid crystal layer 13 also increases. And since the resonance characteristic of the first electrode 11 changes depending on the spatial distribution of the relative dielectric constant of the liquid crystal layer 13, an increase in the amount of change in the spatial distribution of the relative dielectric constant of the liquid crystal layer 13 leads to an increase in Δf / f ０ of the first electrode 11.

[0055] [Second Embodiment] (Configuration Example of First Electrode and Second Electrode] A configuration example of the first electrode and the second electrode according to the second embodiment will be described with reference to FIG. 11. FIG. 11 is a diagram showing a configuration example of the first electrode and the second electrode according to the second embodiment.

[0056] FIG. 11(a) is a diagram showing a configuration example of a first electrode 11A according to the second embodiment. As shown in FIG. 11(a), the first electrode 11A includes a first conductor 21Aa, a first conductor 21Ab, a first conductor 21Ac, a first conductor 21Ad, a second conductor 22Aa, a second conductor 22Ab, a second conductor 22Ac, a second conductor 22Ad, a second conductor 22Ae, a second conductor 22Af, a second conductor 22Ag, and a second conductor 22Ah.

[0057] The first conductors 21Aa to 21Ad are each formed in substantially the same rectangular shape. The first conductors 21Aa to 21Ad are formed with four-way rotational symmetry when viewed from the Z direction.

[0058] The second conductors 22Aa to 22Ah are each formed in a substantially identical U-shape.

[0059] The second conductor 22Aa and the second conductor 22Ab are formed at a predetermined distance from the first side and the second side of the first conductor 21Aa, respectively. Figure 11(b) is a diagram showing the positional relationship between the first conductor and the second conductor according to the second embodiment. As shown in Figure 11(b), the second conductor 22Aa is formed to face the first side of the first conductor 21Aa, and a part of the third side and a part of the fourth side perpendicular to the first side. This is also true for each first conductor and each second conductor according to the second embodiment. The second conductor 22Ab is formed to face the second side of the first conductor 21Aa, and a part of the third side and a part of the fourth side perpendicular to the second side. For example, the second conductor 22Aa and the second conductor 22Ab are formed at positions separated from the first and second sides of the first conductor 21Aa by a distance shorter than the effective wavelength of the electromagnetic wave propagating through the first substrate 15 or the second substrate 16. For example, the second conductor 22Aa and the second conductor 22Ab are formed symmetrically with respect to a center line L1 that bisects the first conductor 21Aa. In other words, the second conductor 22Aa and the second conductor 22Ab are arranged on both sides of the first conductor 21Aa with respect to the center line L1. The first conductor 21Aa is also referred to as the first conductor corresponding to the second conductor 22Aa and the second conductor 22Ab.

[0060] The second conductor 22Ac and the second conductor 22Ad are formed at positions separated by a predetermined distance from the first side and the second side opposite the first side of the first conductor 21Ab, respectively. The second conductor 22Ac is formed to face the first side of the first conductor 21Ab, and a portion of the third side and a portion of the fourth side perpendicular to the first side. The second conductor 22Ad is formed to face the second side of the first conductor 21Aa, and a portion of the third side and a portion of the fourth side perpendicular to the second side. For example, the second conductor 22Ac and the second conductor 22Ad are formed at positions separated by a distance shorter than the effective wavelength of electromagnetic waves propagating through the first substrate 15 or the second substrate 16 from the first side and the second side of the first conductor 21Ab, respectively. For example, the second conductor 22Ac and the second conductor 22Ad are formed symmetrically with respect to a center line L2 that bisects the first conductor 21Ab. In other words, the second conductor 22Ac and the second conductor 22Ad are arranged on both sides of the first conductor 21Ab with respect to the center line L2. The first conductor 21Ab is also referred to as the first conductor corresponding to the second conductor 22Ac and the second conductor 22Ad.

[0061] The second conductor 22Ae and the second conductor 22Af are formed at positions separated by a predetermined distance from the first side and the second side opposite the first side of the first conductor 21Ac, respectively. The second conductor 22Ae is formed to face the first side of the first conductor 21Ac, and a portion of the third side and a portion of the fourth side perpendicular to the first side. The second conductor 22Af is formed to face the second side of the first conductor 21Ac, and a portion of the third side and a portion of the fourth side perpendicular to the second side. For example, the second conductor 22Ae and the second conductor 22Af are formed at positions separated by a distance shorter than the effective wavelength of electromagnetic waves propagating through the first substrate 15 or the second substrate 16 from the first side and the second side of the first conductor 21Ac, respectively. For example, the second conductor 22Ae and the second conductor 22Af are formed symmetrically with respect to a center line L3 that bisects the first conductor 21Ac. In other words, the second conductor 22Ae and the second conductor 22Af are arranged on both sides of the first conductor 21Ac with respect to the center line L3. The first conductor 21Ac is also referred to as the first conductor corresponding to the second conductor 22Ae and the second conductor 22Af.

[0062] The second conductor 22Ag and the second conductor 22Ah are formed at positions separated by a predetermined distance from the first side and the second side opposite the first side of the first conductor 21Ad, respectively. The second conductor 22Ag is formed to face the first side of the first conductor 21Ad, and a portion of the third side and a portion of the fourth side perpendicular to the first side. The second conductor 22Ah is formed to face the second side of the first conductor 21Ad, and a portion of the third side and a portion of the fourth side perpendicular to the second side. For example, the second conductor 22Ag and the second conductor 22Ah are formed at positions separated by a distance shorter than the effective wavelength of electromagnetic waves propagating through the first substrate 15 or the second substrate 16 from the first side and the second side of the first conductor 21Ac, respectively. For example, the second conductor 22Ag and the second conductor 22Ah are formed symmetrically with respect to a center line L4 that bisects the first conductor 21Ad. In other words, the second conductor 22Ag and the second conductor 22Ah are arranged on both sides of the first conductor 21Ad with respect to the center line L4. The first conductor 21Ad is also referred to as the first conductor corresponding to the second conductor 22Ag and the second conductor 22Ah.

[0063] The second conductor 22Aa to the second conductor 22Ah are formed with four-way rotational symmetry when viewed from the Z direction.

[0064] Figure 11(c) shows an example of the configuration of the second electrode 12A according to the second embodiment. As shown in Figure 11(c), an opening 31A is formed in the second electrode 12A. The opening 31A has a rectangular portion 31Aa, a straight portion 31Ab, a straight portion 31Ac, a straight portion 31Ad, and a straight portion 31Ae. The opening 31A is formed with four-way rotational symmetry.

[0065] The rectangular portion 31Aa is a rectangular opening formed in the center of the second electrode 12A. The first side of the rectangular portion 31Aa faces the first vertex of the second electrode 12A. The second side of the rectangular portion 31Aa faces the second vertex of the second electrode 12A. The third side of the rectangular portion 31Aa faces the third vertex of the second electrode 12A. The fourth side of the rectangular portion 31Aa faces the fourth vertex of the second electrode 12A.

[0066] The straight section 31Ab is an elongated straight opening formed between the vicinity of the center of the first side of the rectangular section 31Aa and the first vertex of the second electrode 12A. The straight section 31Ac is an elongated straight opening formed between the vicinity of the center of the second side of the rectangular section 31Aa and the second vertex of the second electrode 12A. The straight section 31Ad is an elongated straight opening formed between the vicinity of the center of the third side of the rectangular section 31Aa and the third vertex of the second electrode 12A. The straight section 31Ae is an elongated straight opening formed between the vicinity of the center of the fourth side of the rectangular section 31Aa and the fourth vertex of the second electrode 12A.

[0067] The positional relationship between the first electrode and the second electrode according to the second embodiment will be explained using Figure 12. Figure 12 is a diagram showing the positional relationship between the first electrode and the second electrode according to the second embodiment.

[0068] Figure 12 shows the positional relationship between the first electrode 11A and the second electrode 12A when viewed from the Z direction of the resonant structure 100A according to the second embodiment.

[0069] The first conductor 21Aa overlaps with the second electrode 12A and the straight section 31Ab when viewed from the Z direction. The first conductor 21Ab overlaps with the second electrode 12A and the straight section 31Ac when viewed from the Z direction. The first conductor 21Ac overlaps with the second electrode 12A and the straight section 31Ad when viewed from the Z direction. The first conductor 21Ad overlaps with the second electrode 12A and the straight section 31Ae when viewed from the Z direction.

[0070] The second conductors 22Aa to 22Ah each overlap only with the second electrode 12A when viewed from the Z direction.

[0071] When viewed from the Z direction, the rectangular portion 31Aa does not overlap with the first conductor 21Aa to the first conductor 21Ad and the second conductor 22A to the second conductor 22Ah.

[0072] Figure 13 shows the simulation results of the characteristics of the resonant structure according to the second embodiment. In Figure 13, the upper section shows the simulation results when no voltage is applied to the liquid crystal layer 13, and the lower section shows the simulation results when a voltage is applied to the liquid crystal layer 13.

[0073] When no voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The frequency is 5.07, the Q value is 93.1, and the eigenvalue is 19.9 [GHz].

[0074] When a voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The frequency is 3.9, the Q value is 96.4, and the eigenvalue is 20.9 [GHz]. In this case, the change in the normalized frequency Δf / f is obtained by normalizing the resonant frequency. ０ The answer is 1 - (19.9 / 20.9) ≈ 0.047.

[0075] (Comparative Example of the Second Embodiment) The positional relationship between the first electrode and the second electrode in the comparative example of the second embodiment will be explained using Figure 14. Figure 14 is a diagram showing the positional relationship between the first electrode and the second electrode in the comparative example of the second embodiment.

[0076] Figure 14 shows the positional relationship between the first electrode 11A and the second electrode 12A when viewed from the Z direction of the resonant structure 100Aa according to the second embodiment. The resonant structure 100Aa according to the comparative example of the second embodiment differs from the resonant structure 100 according to the second embodiment in that it does not have a second conductor 22Aa to a second conductor 22Ah. That is, compared to the comparative example of the second embodiment, the area of ​​the region where the first electrode 11A and the second electrode 12A overlap when viewed from the Z direction is wider in the second embodiment by the area of ​​the second conductor 22Aa to a second conductor 22Ah.

[0077] Figure 15 shows the simulation results of the characteristics of the resonant structure according to a comparative example of the second embodiment. In Figure 15, the upper section shows the simulation results when no voltage is applied to the liquid crystal layer 13, and the lower section shows the simulation results when a voltage is applied to the liquid crystal layer 13.

[0078] When no voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The frequency is 5.07, the Q value is 104, and the eigenvalue is 20.5 [GHz].

[0079] When a voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒThe frequency is 3.9, the Q value is 108, and the eigenvalue is 21.3 [GHz]. In this case, the change in the normalized frequency Δf / f is obtained by normalizing the resonant frequency. ０ The answer is 1 - (20.5 / 21.3) ≈ 0.037.

[0080] In other words, the second embodiment increases the change in resonant frequency from 0.037 to 0.047 by adding a second conductor 22Ah to the configuration of the comparative example of the second embodiment from a second conductor 22Aa. As a result, the second embodiment can configure a resonant structure and radio wave control plate that can achieve a wider bandwidth.

[0081] [Third Embodiment] (Example of Configuration of First and Second Electrodes) An example of the configuration of the first and second electrodes according to the third embodiment will be described with reference to Figure 16. Figure 16 is a diagram showing an example of the configuration of the first and second electrodes according to the third embodiment.

[0082] Figure 16(a) is a diagram showing an example of the configuration of the first electrode 11B according to the third embodiment. As shown in Figure 16(a), the first electrode 11B comprises a first conductor 21Ba, a first conductor 21Bb, a first conductor 21Bc, a first conductor 21Bd, a second conductor 22Ba, a second conductor 22Bb, a second conductor 22Bc, and a second conductor 22Bd.

[0083] The first conductor 21Ba to the first conductor 21Bd are each formed in substantially the same straight line. The first conductor 21Ba to the first conductor 21Bd are formed with four-way rotational symmetry when viewed from the Z direction.

[0084] The second conductor 22Ba to the second conductor 22Bd are each formed in a substantially identical U-shape.

[0085] Each second conductor 22Ba is formed at a predetermined distance from the first side of the first conductor 21Ba. Figure 16(b) is a diagram showing the positional relationship between the first conductor and the second conductor according to the third embodiment. As shown in Figure 16(b), the second conductor 22Ba is formed so as to face the first side of the first conductor 21Ba, and a part of the third side and a part of the fourth side that are perpendicular to the first side. This is also true for each first conductor and each second conductor according to the third embodiment. For example, each second conductor 22Ba is formed at a distance shorter than the effective wavelength of the electromagnetic wave propagating through the first substrate 15 or the second substrate 16 from the first side of the first conductor 21Ba. The third embodiment differs from the second embodiment in that the second conductor is not formed at a predetermined distance from the second side of the first conductor 21Ba that faces the first side. The second conductor 22Ba is formed on only one side of the first conductor 21Ba with respect to the center line L5 that divides the first conductor 21Ba into two equal parts. The first conductor 21Ba is also referred to as the first conductor corresponding to the second conductor 22Ba.

[0086] Each second conductor 22Bb is formed at a predetermined distance from the first edge of the first conductor 21Bb. For example, each second conductor 22Bb is formed at a distance shorter than the effective wavelength of the electromagnetic wave propagating through the first substrate 15 or the second substrate 16 from the first edge of the first conductor 21Bb. The second conductor 22Bb is formed on only one side of the first conductor 21Bb with respect to the center line L6 that divides the first conductor 21Bb into two equal parts. The first conductor 21Bb is also referred to as the first conductor corresponding to the second conductor 22Bb.

[0087] Each second conductor 22Bc is formed at a predetermined distance from the first side of the first conductor 21Bc. For example, each second conductor 22Bc is formed at a distance shorter than the effective wavelength of the electromagnetic wave propagating through the first substrate 15 or the second substrate 16 from the first side of the first conductor 21Bc. The second conductor 22Bc is formed on only one side of the first conductor 21Bc with respect to the center line L7 that divides the first conductor 21Bc into two equal parts. The first conductor 21Bc is also referred to as the first conductor corresponding to the second conductor 22Bc.

[0088] Each second conductor 22Bd is formed at a predetermined distance from the first side of the first conductor 21Bd. For example, each second conductor 22Bd is formed at a distance shorter than the effective wavelength of the electromagnetic wave propagating through the first substrate 15 or the second substrate 16 from the first side of the first conductor 21Bd. The second conductor 22Bd is formed on only one side of the first conductor 21Bd with respect to the center line L8 that divides the first conductor 21Bd into two equal parts. The first conductor 21Bd is also referred to as the first conductor corresponding to the second conductor 22Bd.

[0089] The second conductor 22Ba to the second conductor 22Bd are formed with four-way rotational symmetry when viewed from the Z direction.

[0090] Figure 16(c) shows an example of the configuration of the second electrode 12B according to the third embodiment. As shown in Figure 16(c), the second electrode 12B has a rectangular opening 31B. The opening 31B is formed with four-dimensional rotational symmetry.

[0091] The positional relationship between the first electrode and the second electrode according to the third embodiment will be explained using Figure 17. Figure 17 is a diagram showing the positional relationship between the first electrode and the second electrode according to the third embodiment.

[0092] Figure 17 shows the positional relationship between the first electrode 11B and the second electrode 12B when viewed from the Z direction of the resonant structure 100B according to the third embodiment.

[0093] The first conductor 21Ba to the first conductor 21Bd overlap with the second electrode 12B and the opening 31B, respectively, when viewed from the Z direction.

[0094] The second conductors 22Ba and 22Bd each overlap only with the second electrode 12B when viewed from the Z direction.

[0095] When viewed from the Z direction, the opening 31B does not overlap with the second conductor 22Ba to the second conductor 22Bd.

[0096] Figure 18 shows the simulation results of the characteristics of the resonant structure according to the third embodiment. In Figure 18, the upper section shows the simulation results when no voltage is applied to the liquid crystal layer 13, and the lower section shows the simulation results when a voltage is applied to the liquid crystal layer 13.

[0097] When no voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The frequency is 5.07, the Q value is 282, and the eigenvalue is 26.9 [GHz].

[0098] When a voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The frequency is 3.9, the Q value is 297, and the eigenvalue is 27.1 [GHz]. In this case, the change in the normalized frequency Δf / f is obtained by normalizing the resonant frequency. ０ Therefore, 1 - (26.9 / 27.1) ≈ 0.0073.

[0099] (Comparative Example of the Third Embodiment) The positional relationship between the first electrode and the second electrode in the comparative example of the third embodiment will be explained using Figure 19. Figure 19 is a diagram showing the positional relationship between the first electrode and the second electrode in the comparative example of the third embodiment.

[0100] Figure 19 shows the positional relationship between the first electrode 11B and the second electrode 12B when viewed from the Z direction of the resonant structure 100Ba according to the second embodiment. The resonant structure 100Ba according to the comparative example of the third embodiment differs from the resonant structure 100 according to the third embodiment in that it does not have a second conductor 22Ba to the second conductor 22Bd. That is, compared to the comparative example of the third embodiment, the area of ​​the region where the first electrode 11B and the second electrode 12B overlap when viewed from the Z direction is wider in the third embodiment by the area of ​​the second conductor 22Ba to the second conductor 22Bd.

[0101] Figure 20 shows the simulation results of the characteristics of the resonant structure according to a comparative example of the third embodiment. In Figure 20, the upper section shows the simulation results when no voltage is applied to the liquid crystal layer 13, and the lower section shows the simulation results when a voltage is applied to the liquid crystal layer 13.

[0102] When no voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒ The frequency is 5.07, the Q value is 311, and the eigenvalue is 27.4 [GHz].

[0103] When a voltage is applied to the liquid crystal layer 13, the dielectric constant ε of the liquid crystal layer 13 ｒThe frequency is 3.9, the Q value is 316, and the eigenvalue is 27.5 [GHz]. In this case, the change in the normalized frequency Δf / f is obtained by normalizing the resonant frequency. ０ The answer is 1 - (27.4 / 27.5) ≈ 0.0036.

[0104] In other words, the third embodiment increases the change in resonant frequency from 0.0036 to 0.0073 by adding a second conductor 22Bd to the configuration of the comparative example of the third embodiment, instead of a second conductor 22Ba. As a result, the third embodiment can configure a unit structure and radio wave control board that can achieve a wide bandwidth.

[0105] [Another Embodiment] (First Example) In the embodiments described above, the unit structure 10 was described as having two resonant structures, resonant structure 100-1 and resonant structure 100-2, stacked along the Z-axis, but the disclosure is not limited thereto. In the disclosure, the unit structure may have three or more resonant structures stacked along the Z-axis.

[0106] An example of the configuration of a unit structure according to another embodiment will be described using Figure 21. Figure 21 is a diagram showing an example of the configuration of a unit structure according to another embodiment.

[0107] As shown in Figure 21, the unit structure 10A comprises a resonant structure 100-1, a resonant structure 100-2, a resonant structure 100-3, and a resonant structure 100-4. The unit structure 10A differs from the unit structure 10 shown in Figure 4 in that it comprises a resonant structure 100-3 and a resonant structure 100-4. That is, in another embodiment, for example, the radio wave control board 1A has a two-dimensional arrangement of unit structures 10 in which four resonant structures, from resonant structure 100-1 to resonant structure 100-4, are stacked along the Z-axis.

[0108] An adhesive layer 17-3 is formed on the other side of the second substrate 16 of the resonant structure 100-2. An adhesive layer 17-4 is formed on the other side of the second substrate 16 of the resonant structure 100-3. The adhesive layers 17-3 and 17-4 are, for example, OCA, but are not limited to this. An adjustment conductor 18 for adjusting the coupling between the resonant structure 100-2 and the resonant structure 100-3 is arranged between the adhesive layers 17-3 and 17-4.

[0109] An adhesive layer 17-3 is formed on the other side of the second substrate 16 of the resonant structure 100-2. An adhesive layer 17-4 is formed on the other side of the second substrate 16 of the resonant structure 100-3. The adhesive layers 17-3 and 17-4 are, for example, OCA, but are not limited to this. An adjustment conductor 18 for adjusting the coupling between the resonant structure 100-2 and the resonant structure 100-3 is arranged between the adhesive layers 17-3 and 17-4.

[0110] An adhesive layer 17-5 is formed on the other side of the first substrate 15 of the resonant structure 100-3. An adhesive layer 17-6 is formed on the other side of the second substrate 16 of the resonant structure 100-4. The adhesive layers 17-5 and 17-6 are, for example, OCA, but are not limited to this. An adjustment conductor 18 for adjusting the coupling between the resonant structure 100-3 and the resonant structure 100-4 is arranged between the adhesive layers 17-5 and 17-6.

[0111] In other words, in the unit structure 10A, the resonant structures 100-1 to 100-4 are stacked in the Z-axis direction by adhesive layers 17-1 to 17-6 and adjustment conductors 18. As mentioned above, each adhesive layer is optional. Also, in the unit structure 10A of Figure 21, the first electrode 11 of resonant structures 100-1 and 100-2 is above the second electrode 12 on the Z-axis, while the first electrode 11 of resonant structures 100-3 and 100-4 is below the second electrode 12 on the Z-axis. That is, each electrode (first electrode and second electrode) of the unit structure 10A is arranged symmetrically in the Z-axis direction. In this way, it is preferable that each electrode of the unit structure is arranged symmetrically in the stacking direction of the resonant structures (the Z-axis direction in Figure 21). This is because, in actual communication, radio waves travel in both directions, but if the structure is asymmetrical in the stacking direction, for example, the intensity of the reflected wave will differ depending on whether the incident wave arrives from the +Z direction or the -Z direction, which can lead to adverse effects such as interference.

[0112] (Second Example) In the embodiments described above, the resonant structure was described as comprising a liquid crystal layer 13, but the present disclosure is not limited thereto. The resonant structure of the present disclosure does not necessarily have to comprise a liquid crystal layer 13.

[0113] Furthermore, the present disclosure may also take the following configurations: (1) A resonant structure included in a radio wave control board, comprising: a resonant conductor disposed on a first surface and a ground conductor disposed on a second surface located away from the first surface in a first direction, wherein the resonant conductor comprises: a first conductor and a second conductor disposed spaced apart from the first conductor, and the ground conductor has at least one opening when viewed in plan from the first direction. (2) The resonant structure according to (1), wherein the second conductor is positioned such that at least a portion of it overlaps with the ground conductor when viewed in plan from the first direction. (3) The resonant structure according to (1) or (2), wherein the resonant conductor comprises a plurality of the second conductors, and the plurality of the second conductors are arranged in a four-way rotationally symmetric configuration when viewed in plan from the first direction. (4) The resonant conductor comprises a plurality of first conductors and a plurality of second conductors, the plurality of second conductors are spaced apart from the corresponding first conductor, and the plurality of first conductors and the plurality of second conductors are arranged in a four-way rotationally symmetric arrangement when viewed in plan from the first direction, as described in (1) or (2). (5) The resonant structure according to (4), the second conductors are arranged on both sides of the first conductor with respect to a center line that bisects the corresponding first conductor when viewed in plan from the first direction. (6) The resonant structure according to (4), the second conductor is arranged on only one side of the first conductor with respect to a center line that bisects the corresponding first conductor when viewed in plan from the first direction. (7) The resonant structure according to any one of (1) to (6), the second conductor is arranged at a distance shorter than the effective wavelength of the electromagnetic wave propagating through the resonant structure from the first conductor. (8) The resonant structure according to any one of (1) to (7), further comprising a liquid crystal layer disposed between the resonant conductor and the ground conductor. (9) A radio wave control board including the resonant structure according to any one of (1) to (8).

[0114] 1, 1A Radio wave control board 2 Substrate 10, 10-1, 10a, 10A, 10b, 10c, 10d Unit structure 11, 11a, 11A, 11B First electrode 12, 12a, 12A, 12B Second electrode 13 Liquid crystal layer 14 Liquid crystal molecule 15 First substrate 16 Second substrate 17-1, 17-2, 17-3, 17-4, 17-5, 17-6 Adhesive layer 18 Adjusting conductor 21, 21Aa, 21Ab, 21Ac, 21Ad, 21Ba, 21Bb, 21Bc, 21Bd First conductor 22a, 22A, 22Aa, 22Ab, 22Ac, 22Ad, 22Ae, 22Af, 22Ag, 22Ah, 22b, 22B, 22Ba, 22Bb, 22Bc, 22Bd, 22c, 22d Second conductor 31, 31A, 31B, 41 Opening 31a, 31b, 31c, 31d Tip 31Aa Rectangular section 31Ab, 31Ac, 31Ad, 31Ae Straight section 51, 52, 53, 54, 61, 62, 63, 64 Superimposed region 100, 100-1, 100-2, 100-3, 100-4, 100A, 100Aa, 100B, 100Ba Resonance structure

Claims

1. A resonant structure included in a radio wave control board, comprising: a resonant conductor disposed on a first surface and a ground conductor disposed on a second surface located away from the first surface in a first direction, wherein the resonant conductor comprises a first conductor and a second conductor spaced apart from the first conductor, and the ground conductor has at least one opening when viewed from the first direction in a plan view.

2. The resonant structure according to claim 1, wherein the second conductor is positioned such that, when viewed from the first direction in a plan view, at least a portion of it overlaps with the ground conductor.

3. The resonant structure according to claim 1 or 2, wherein the resonant conductor comprises a plurality of second conductors, and the plurality of second conductors are arranged in a four-way rotationally symmetric arrangement when viewed in plan from the first direction.

4. The resonant conductor comprises a plurality of first conductors and a plurality of second conductors, each of which is spaced apart from a corresponding first conductor, and the plurality of first conductors and the plurality of second conductors are arranged in a four-way rotationally symmetric arrangement when viewed in plan from the first direction, according to claim 1 or 2.

5. The resonant structure according to claim 4, wherein the second conductor is arranged on both sides of the first conductor with respect to a center line that bisects the corresponding first conductor when viewed from the first direction.

6. The resonant structure according to claim 4, wherein the second conductor is positioned on only one side of the first conductor with respect to a center line that bisects the corresponding first conductor when viewed from the first direction.

7. The resonant structure according to any one of claims 1 to 6, wherein the second conductor is positioned at a distance shorter than the effective wavelength of the electromagnetic wave propagating through the resonant structure from the first conductor.

8. The resonant structure according to any one of claims 1 to 7, further comprising a liquid crystal layer disposed between the resonant conductor and the ground conductor.

9. A radio wave control board comprising the resonant structure described in any one of claims 1 to 8.

10. The radio wave control board according to claim 9, wherein the resonant structure further comprises a liquid crystal layer disposed between the resonant conductor and the ground conductor.

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