Radio wave control plate and complex resonator

Abstract

A radio wave control plate according to the present invention comprises a plurality of unit structures arranged on a surface. The unit structures each comprise a plurality of resonators aligned in a first direction perpendicular to the surface, and dielectric layers positioned between the plurality of resonators. At least one of the plurality of resonators is formed so that at least a section of a peripheral part become thinner towards the end thereof.

Description

Radio wave control plate and composite resonator

[0001] The present disclosure relates to a radio wave control panel and a composite resonator.

[0002] There are known techniques for controlling electromagnetic waves without using a dielectric lens. For example, Patent Document 1 describes a technique for refracting radio waves by changing the parameters of each element in a structure in which resonator elements are arranged.

[0003] JP 2015-231182 A

[0004] The radio wave control plate of the present disclosure includes a plurality of unit structures arranged on a surface, each of which has a plurality of resonators arranged in a first direction perpendicular to the surface, and a dielectric layer positioned between the plurality of resonators, and at least one of the plurality of resonators has at least a portion of its peripheral edge formed to be thinner toward the end.

[0005] The composite resonator of the present disclosure comprises a plurality of resonators arranged in a first direction perpendicular to a surface, and a dielectric layer positioned between the plurality of resonators, and at least one of the plurality of resonators has at least a portion of its peripheral edge formed to be thinner toward the end.

[0006] Fig. 1 is a diagram for explaining an overview of a radio wave control plate. Fig. 2 is a diagram showing an overview of a unit structure. Fig. 3 is a schematic diagram of a cross section of a resonator according to a first embodiment. Fig. 4 is a schematic diagram of the resonator according to the first embodiment as seen from above. Fig. 5 is a diagram for explaining a conductor pattern of a resonator inside a unit structure according to a second embodiment.

[0007] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0008] In the following description, an XYZ Cartesian coordinate system is set, and the positional relationship of each part will be described with reference to this XYZ Cartesian coordinate system. The direction parallel to the X axis in a horizontal plane is defined as the X-axis direction, the direction parallel to the Y axis in the horizontal plane perpendicular to the X axis is defined as the Y-axis direction, and the direction parallel to the Z axis perpendicular to the horizontal plane is defined as the Z-axis direction. Furthermore, the plane including the X axis and Y axis will be referred to as the XY plane as appropriate, the plane including the X axis and Z axis will be referred to as the XZ plane as appropriate, and the plane including the Y axis and Z axis will be referred to as the YZ plane as appropriate. The XY plane is parallel to the horizontal plane. The XY plane, XZ plane, and YZ plane are perpendicular to each other.

[0009] (Radio wave control board) The outline of the radio wave control board will be explained using Fig. 1. Fig. 1 is a diagram for explaining the outline of the radio wave control board.

[0010] The radio wave control board 1 is a plate-shaped member configured to be able to reflect or transmit (refract) radio waves transmitted from a base station. For example, when receiving radio waves transmitted from a base station, the radio wave control board 1 is configured to reflect or refract the radio waves at a predetermined angle. The radio wave control board 1 can be configured, for example, from a metamaterial that changes the phase of the incident wave.

[0011] 1, the radio wave control plate 1 may include, for example, a substrate 2 and unit structures 10a, 10b, 10c, and 10d. When there is no need to distinguish between the unit structures 10a to 10d, they will be collectively referred to as unit structures 10. The unit structures 10 are also called composite resonators.

[0012] The unit structures 10a, 10b, 10c, and 10d may 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 have, for example, but is not limited to, a rectangular shape. The unit structures 10a, 10b, 10c, and 10d may be arranged two-dimensionally.

[0013] In the radio wave control board 1, a plurality of unit structures 10a are arranged along the X-axis direction on one tier. A plurality of unit structures 10b are arranged along the X-axis direction on the tier above the tier on which unit structures 10a are arranged. A plurality of unit structures 10c are arranged along the X-axis direction on the tier above the tier on which unit structures 10b are arranged. A plurality of unit structures 10d are arranged along the X-axis direction on the tier above the tier on which unit structures 10c are installed. In the example shown in FIG. 1 , unit structures 10a, unit structures 10b, unit structures 10c, and unit structures 10d are arranged periodically along the Y-axis direction.

[0014] Unit structure 10a, unit structure 10b, unit structure 10c, and unit structure 10d are all different in size. In the example shown in Fig. 1, unit structure 10a is the largest, followed by unit structure 10b, unit structure 10c, and unit structure 10d in order of size. That is, radio wave control board 1 has a structure in which a plurality of unit structures 10 of different sizes are periodically arranged.

[0015] The unit structures 10a to 10d may each have a different amount of phase change in the received radio waves. That is, the unit structures 10a to 10d are periodically arranged so as to have a gradient in the amount of phase change. The unit structures 10a to 10d each have a rectangular shape, but are not limited to this. By changing the size and shape of the unit structures 10a to 10d, the frequency band and amount of phase change of the radio waves to be reflected or refracted can be adjusted.

[0016] An outline of the unit structure will be described with reference to Fig. 2. Fig. 2 is a diagram showing an outline of the unit structure.

[0017] As shown in FIG. 2 , the unit structure 10 includes a first resonator 11 a, a second resonator 11 b, a third resonator 11 c, a fourth resonator 11 d, a first reference conductor 21 a, a second reference conductor 21 b, a third reference conductor 21 c, a first dielectric layer 31, a second dielectric layer 32, a third dielectric layer 33, a fourth dielectric layer 34, a fifth dielectric layer 35, and a sixth dielectric layer 36.

[0018] The first resonator 11a is a resonator made of a conductive material (metal material) and is formed on the top surface of the unit structure 10.

[0019] The second resonator 11b and the third resonator 11c are resonators made of conductive materials and are formed inside the unit structure 10.

[0020] The fourth resonator 11d is a resonator made of a conductive material. The fourth resonator 11d is formed on the bottom surface of the unit structure 10. The bottom surface is also called the back surface. The fourth resonator 11d is also called a second metal element.

[0021] The first reference conductor 21a is a ground conductor made of a conductive material. The first reference conductor 21a is formed inside the unit structure 10. The first reference conductor 21a is formed between the first resonator 11a and the second resonator 11b. The first resonator 11a and the second resonator 11b are magnetically or capacitively connected via the first reference conductor 21a. The first reference conductor 21a is a coupling adjustment conductor that adjusts the strength of coupling between the first resonator 11a and the second resonator 11b.

[0022] The second reference conductor 21b is a ground conductor made of a conductive material. The second reference conductor 21b is formed inside the unit structure 10. The second reference conductor 21b is formed between the second resonator 11b and the third resonator 11c. The second resonator 11b and the third resonator 11c are magnetically or capacitively connected via the second reference conductor 21b. The second reference conductor 21b is a coupling adjustment conductor that adjusts the strength of coupling between the second resonator 11b and the third resonator 11c.

[0023] The third reference conductor 21c is a ground conductor made of a conductive material. The third reference conductor 21c is formed inside the unit structure 10. The third reference conductor 21c is formed between the third resonator 11c and the fourth resonator 11d. The third resonator 11c and the fourth resonator 11d are magnetically or capacitively connected via the third reference conductor 21c. The third reference conductor 21c is a coupling adjustment conductor that adjusts the strength of coupling between the third resonator 11c and the fourth resonator 11d.

[0024] The first dielectric layer 31 is a dielectric substrate located between the first resonator 11a and the first reference conductor 21a. The first dielectric layer 31 includes a core layer 311 and a prepreg layer 312.

[0025] The second dielectric layer 32 is a dielectric substrate located between the first reference conductor 21 a and the second resonator 11 b. The second dielectric layer 32 includes a core layer 321 and a prepreg layer 322.

[0026] The third dielectric layer 33 is a dielectric substrate located between the second resonator 11b and the second reference conductor 21b. The third dielectric layer 33 includes a core layer 331 and a prepreg layer 332.

[0027] The fourth dielectric layer 34 is a dielectric substrate located between the second reference conductor 21b and the third resonator 11c. The fourth dielectric layer 34 includes a core layer 341 and a prepreg layer 342.

[0028] The fifth dielectric layer 35 is a dielectric substrate located between the third resonator 11c and the third reference conductor 21c. The fifth dielectric layer 35 includes a core layer 351 and a prepreg layer 352.

[0029] The sixth dielectric layer 36 is a dielectric substrate located between the third reference conductor 21c and the fourth resonator 11d. The sixth dielectric layer 36 includes a core layer 361 and a prepreg layer 362.

[0030] As shown in FIG. 2, the unit structure 10 has seven layers: a first resonator 11a, a second resonator 11b, a third resonator 11c, a fourth resonator 11d, a first reference conductor 21a, a second reference conductor 21b, and a third reference conductor 21c; however, the present disclosure is not limited thereto.

[0031] When it is not necessary to distinguish between the first resonator 11a to the fourth resonator 11d, they are collectively referred to as the resonators 11. When it is not necessary to distinguish between the first reference conductor 21a to the third reference conductor 21c, they are collectively referred to as the reference conductors 21.

[0032] In the unit structure 10, the dimensions of the conductor patterns of each resonator 11 and each reference conductor 21 are appropriately designed so that the radio wave control board 1 has the desired reflection or transmission characteristics. However, if the dimensions of the conductor patterns of each resonator 11 and each reference conductor 21 deviate from the design values ​​due to manufacturing variations or the like, the resonant frequency will deviate. As a result, the amount of change in the transmission phase or the reflection phase will deviate from the desired frequency, which may result in a decrease in communication quality. Because the amount of change in the transmission phase or the reflection phase is large, it is necessary to lower the Q value. Therefore, in the present disclosure, the conductor patterns of each resonator 11 are formed to lower the Q value, thereby improving the communication quality of the radio wave control board 1.

[0033] [First embodiment] (Conductor pattern of resonator) The conductor pattern of the resonator according to the first embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a schematic cross-sectional view of the resonator according to the first embodiment. Fig. 4 is a schematic top view of the resonator according to the first embodiment.

[0034] As shown in Fig. 3, the resonator 11 has peripheral portions R1 and R2 that are thinner toward the ends. The resonator 11 has, for example, a trapezoidal cross section. Therefore, the area of ​​the upper surface 11A and the area of ​​the lower surface 11B of the resonator 11 are different. For example, the area of ​​the upper surface 11A of the resonator 11 is smaller than the area of ​​the lower surface 11B. In the first embodiment, the Q value of the unit structure 10 can be reduced by thinning the peripheral portions R1 and R2 of the resonator 11 toward the ends.

[0035] In this embodiment, at least one of the multiple resonators 11 included in the radio wave control plate 1 may have at least a portion of its periphery thinned toward its edge. As shown in FIG. 4 , when the resonator 11 is rectangular, the resonator 11 has an upper edge 11C, a lower edge 11D, a left edge 11E, and a right edge 11F. In this case, the resonator 11 may have at least a portion of at least one of the periphery R3 of the upper edge 11C, the periphery R4 of the lower edge 11D, the periphery R1 of the left edge 11E, and the periphery R2 of the right edge 11F thinned toward its edge. In this case, because current flows concentratedly in the center of each side of the resonator 11, it is preferable to thin the center of at least one of the peripheries thin toward its edge. In this embodiment, thinning the center of the periphery thins the center toward its edge, thereby more appropriately reducing the Q value of the unit structure 10.

[0036] 4, it is more preferable that the entire peripheral edge portions R1, R2, R3, and R4 (all peripheral edges) be formed so as to become thinner toward the ends. By forming the entire peripheral edge portions R1, R2, R3, and R4 so as to become thinner toward the ends, the Q value of unit structure 10 can be more appropriately reduced.

[0037] Second Embodiment (Conductor Pattern of Resonator Inside Unit Structure) The conductor pattern of the resonator inside the unit structure according to the second embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining the conductor pattern of the resonator inside the unit structure according to the second embodiment.

[0038] FIG. 5 shows a resonator 11 formed inside the unit structure 10. FIG. 5 is an example of an SEM (Scanning Electron Microscope) image of the resonator 11 formed inside the unit structure 10. The resonator 11 is formed inside the unit structure 10 between a core layer 41 of the dielectric layer 40 and a prepreg layer 42. The core layer 41 contains glass cloth 51. The prepreg layer 42 contains glass cloth 52. The glass cloth 51 is larger than the glass cloth 52. In this embodiment, of the two dielectric layers sandwiching the resonator 11, the dielectric layer containing the relatively large glass cloth is called the core layer, and the dielectric layer containing the relatively small glass cloth is called the prepreg layer.

[0039] When trying to thin the end of the resonator 11 inside the unit structure 10, the resonant frequency may differ depending on whether or not there is glass cloth near the thinned portion, resulting in a deterioration in characteristics. This is because the relative permittivity differs between the resin part of the dielectric layer and the glass cloth part. It is difficult to keep the glass cloth away from the resonator 11.

[0040] Therefore, in the second embodiment, as shown in FIG. 5 , the thickness of the resonator 11 on the core layer 41 side is reduced to maintain a low dielectric constant around the thinner portion. Specifically, in the second embodiment, the area of ​​the upper surface 11A on the core layer 41 side is made larger than the area of ​​the lower surface 11B on the prepreg layer 42 side. In other words, in the second embodiment, the distance between the relatively large upper surface 11A and the glass cloth 51 is more likely to be longer than the distance between the relatively small lower surface 11B and the glass cloth 52. This increases the likelihood that the distance between the lower surface 11B and the glass cloth 52 will be closer than the distance between the upper surface 11A and the glass cloth 51, thereby reducing the deviation of the resonant frequency and achieving stable characteristics. The upper surface 11A is also referred to as the first surface. The lower surface 11B is also referred to as the second surface.

[0041] Third Embodiment (Surface Shape of Resonator) The surface shape of a resonator according to a third embodiment will be described.

[0042] When the surface of the resonator 11 of the unit structure 10 is smooth, the conductor loss at the surface is small. Therefore, in the third embodiment, at least one of the upper and lower surfaces of the resonator 11 is roughened to reduce the Q value. In other words, at least one of the upper and lower surfaces of the resonator 11 is uneven. Specifically, the surface roughness of at least one of the upper and lower surfaces of the resonator 11 is preferably 0.2 μm (micrometers) or more, and more preferably 1 μm or more. The surface roughness of the upper or lower surface of the resonator 11 can be calculated as the root-mean-square roughness by performing image analysis on an SEM image, for example. Furthermore, in the third embodiment, it is preferable to form unevenness on both the upper and lower surfaces of the resonator 11. In this case, the surface roughness of the upper and lower surfaces of the resonator 11 may be the same or different. By forming unevenness on both the upper and lower surfaces of the resonator 11, the Q value can be appropriately reduced.

[0043] Fourth Embodiment (Surface Shape of Resonator) The surface shape of a resonator according to a fourth embodiment will be described.

[0044] As shown in FIG. 3 , when the areas of the upper surface 11A and the lower surface 11B of the resonator 11 are different, the effect of reducing the Q value differs between forming concaves and convexes on the upper surface 11A and forming concaves and convexes on the lower surface 11B. In the fourth embodiment, it is preferable to form concaves and convexes on at least the surface with the larger area of ​​the upper surface 11A or the lower surface 11B of the resonator 11. In the fourth embodiment, by forming concaves and convexes on the surface with the larger area of ​​the upper surface 11A or the lower surface 11B of the resonator 11, the unit structure 10 can appropriately reduce the Q value and achieve more stable characteristics. Furthermore, in the fourth embodiment, it is preferable to form concaves and convexes on both the upper surface 11A and the lower surface 11B of the resonator 11.

[0045] [Effect] Radio wave control plate 1 according to the first aspect of the present disclosure includes a plurality of unit structures 10 arranged on a surface, and unit structures 10 each include a plurality of resonators 11 arranged in a first direction perpendicular to the surface, and a dielectric layer positioned between the plurality of resonators 11, and at least one of the plurality of resonators 11 has at least a portion of its peripheral edge formed to be thinner toward the end. According to the present disclosure, at least one of the plurality of resonators 11 has at least a portion of its peripheral edge formed to be thinner toward the end, thereby reducing the Q value and improving communication quality.

[0046] A radio wave control plate 1 according to a second aspect of the present disclosure is radio wave control plate 1 according to the first aspect, in which at least a portion of the peripheral edge is formed thinner toward the end than the average thickness of the resonator. According to the present disclosure, by appropriately thinning at least a portion of the peripheral edge toward the end, communication quality can be improved.

[0047] A radio wave control board 1 according to a third aspect of the present disclosure is radio wave control board 1 according to the first or second aspect, wherein at least one of the plurality of resonators 11 has a first surface and a second surface having an area smaller than that of the first surface, the first surface being located on the core layer side of the dielectric layer, and the second surface being located on the prepreg layer side of the dielectric layer. According to the present disclosure, by appropriately positioning the first surface and the second surface, communication quality can be improved.

[0048] A radio wave control board 1 according to a fourth aspect of the present disclosure is radio wave control board 1 according to either the first or second aspect, wherein at least one of the plurality of resonators 11 has a first surface and a second surface having an area smaller than that of the first surface, and the distance between the first surface and a glass cloth included in a layer of the dielectric layer that contacts the first surface is longer than the distance between the second surface and a glass cloth included in a layer of the dielectric layer that contacts the second surface. According to the present disclosure, communication quality can be improved by appropriately setting the distance between the first surface and the glass cloth and the distance between the second surface and the glass cloth.

[0049] A radio wave control plate 1 according to a fifth aspect of the present disclosure is radio wave control plate 1 according to any one of the first to fourth aspects, wherein at least one of the first and second surfaces has an uneven surface formed thereon. According to the present disclosure, by forming an uneven surface on at least one of the first and second surfaces, communication quality can be improved.

[0050] A radio wave control plate 1 according to a sixth aspect of the present disclosure is radio wave control plate 1 according to the fifth aspect, wherein, of the first and second surfaces, at least the second surface has irregularities formed thereon. According to the present disclosure, forming irregularities on at least the second surface can improve communication quality.

[0051] A radio wave control plate 1 according to a seventh aspect of the present disclosure is radio wave control plate 1 according to the sixth aspect, in which unevenness is formed on both the first and second surfaces. According to the present disclosure, by forming unevenness on both the first and second surfaces, communication quality can be improved.

[0052] A radio wave control plate 1 according to an eighth aspect of the present disclosure is radio wave control plate 1 according to any one of the fifth to seventh aspects, wherein the surface roughness of the first and second surfaces on which the irregularities are formed is 0.2 μm or more. According to the present disclosure, by appropriately setting the surface roughness, communication quality can be improved.

[0053] A composite resonator according to a ninth aspect of the present disclosure includes a plurality of resonators 11 arranged in a first direction perpendicular to a surface, and a dielectric layer positioned between the plurality of resonators 11, wherein at least one of the plurality of resonators 11 has at least a portion of its peripheral edge formed to be thinner toward the end. According to the present disclosure, at least one of the plurality of resonators 11 has at least a portion of its peripheral edge formed to be thinner toward the end, thereby reducing the Q value and improving communication quality.

[0054] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0055] REFERENCE SIGNS LIST 1 Radio wave control board 10 Unit structure 11 Resonator 11a First resonator 11b Second resonator 11c Third resonator 11d Fourth resonator 21a First reference conductor 21b Second reference conductor 21c Third reference conductor 31 First dielectric layer 32 Second dielectric layer 33 Third dielectric layer 34 Fourth dielectric layer 35 Fifth dielectric layer 36 Sixth dielectric layer 311, 321, 331, 341, 351, 361, 41 Core layer 312, 322, 332, 342, 352, 362, 42 Prepreg layer

Claims

1. A radio wave control plate comprising a plurality of unit structures arranged on a surface, the unit structures comprising: a plurality of resonators arranged in a first direction perpendicular to the surface; and a dielectric layer positioned between the plurality of resonators, wherein at least one of the plurality of resonators has at least a portion of its peripheral edge formed so as to be thinner toward the end.

2. The radio wave control plate according to claim 1, wherein at least a part of the peripheral portion is formed to be thinner than the average thickness of the resonator toward the end.

3. A radio wave control board as described in claim 1 or claim 2, wherein at least one of the multiple resonators has a first surface and a second surface having an area smaller than that of the first surface, the first surface being located on the core layer side of the dielectric layer, and the second surface being located on the prepreg layer side of the dielectric layer.

4. A radio wave control board as described in claim 1 or claim 2, wherein at least one of the plurality of resonators has a first surface and a second surface having an area smaller than that of the first surface, and the distance between the first surface and a glass cloth included in a layer of the dielectric layer that contacts the first surface is longer than the distance between the second surface and a glass cloth included in a layer of the dielectric layer that contacts the second surface.

5. The radio wave control plate according to claim 3, wherein at least one of the first surface and the second surface has an uneven surface.

6. The radio wave control plate according to claim 5, wherein of the first surface and the second surface, at least the second surface has an uneven surface.

7. The radio wave control plate according to claim 6, wherein projections and recesses are formed on both the first surface and the second surface.

8. The radio wave control plate according to claim 5, wherein the surface roughness of the surface on which the irregularities are formed of the first surface and the second surface is 0.2 μm or more.

9. A composite resonator comprising: a plurality of resonators arranged in a first direction perpendicular to a surface; and a dielectric layer located between the plurality of resonators, wherein at least one of the plurality of resonators has at least a portion of a peripheral edge formed so as to be thinner toward the end.