JP2017005578A - Metamaterial structure, and antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metamaterial structure, and an antenna device capable of interference among signals.SOLUTION: A metamaterial structure includes plural cells which are regularly disposed. Each of the cells has a metamaterial structure which has a first layer including: a first ring-shaped peripheral part; a first central part disposed inside the first peripheral part; and a first connection part which connects the first peripheral part and the first central part therebetween.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metamaterial structure and an antenna device.

  There is a pattern antenna such as a millimeter wave that forms a plurality of planar antennas on one surface of the same circuit board. The ground (GND) on the circuit board serves as an electric wall and reflects the electromagnetic field.

Special table 2014-527366 gazette JP 2014-086949 A Special table 2013-532436 gazette JP 2005-094440 A Japanese Patent Application Laid-Open No. 09-232822 JP 2006-245984 A

In a pattern antenna such as a millimeter wave, interference with a desired signal wave may occur due to reflection of an electromagnetic field, and the effect may appear as a ripple. If the distance between the antennas is close, the transmission wave from one antenna wraps around the other antenna, the signal-to-noise ratio (SNR) deteriorates, and the device characteristics of the device including the pattern antenna deteriorate. Sometimes. Ripple can be attenuated by increasing the distance between GND and the antenna or the antenna, but this goes against modern high-density packaging and product miniaturization. Therefore, it is difficult to achieve both high-density mounting, product miniaturization, and ripple attenuation.

  Interference control may be performed by providing an EBG (Electromagnetic Band Gap) structure, which is a kind of metamaterial structure, on a circuit board including a pattern antenna. The metamaterial structure is a structure such as an artifact having characteristics that do not exist in nature. The EBG structure has a characteristic that electromagnetic wave propagation is suppressed in a specific frequency band, and is a structure formed by periodically arranging a plurality of cells composed of conductors or the like. Although there is a method using SRR (Sprit Ring Resonator) as an EBG cell, conventional SRR takes a predetermined space around the SRR, so that it is not possible to secure a wide band and sufficient attenuation in a high frequency region such as millimeter waves. There's a problem.

  It is an object of the present invention to provide a metamaterial structure and an antenna device that suppress signal interference.

The present invention employs the following means in order to solve the above problems.
That is, the first aspect is
A metamaterial structure in which a plurality of cells are periodically arranged,
The cell is
A ring-shaped first peripheral edge;
A first central portion disposed inside the first peripheral edge;
Including a first layer having a first connection portion connecting the first peripheral edge portion and the first central portion;
Metamaterial structure.
According to the first aspect, the split ring is formed by the space portion surrounded by the first peripheral edge portion, the first central portion, and the first connection portion of the first layer.

  ADVANTAGE OF THE INVENTION According to this invention, the metamaterial structure and antenna apparatus which suppress signal interference can be provided.

FIG. 1 is a diagram illustrating an example of a top view of one cell (cell 1) of a metamaterial structure. FIG. 2 is a diagram illustrating an example of a perspective view of one cell (cell 2) having a metamaterial structure. FIG. 3 is a diagram illustrating an example of a top view of the second layer of one cell (cell 2) of the metamaterial structure. FIG. 4 is a diagram illustrating an example of a top view of one cell (cell 2) having a metamaterial structure. FIG. 5 is a diagram illustrating an example of a perspective view of one cell (cell 3) having a metamaterial structure. FIG. 6 is a diagram illustrating an example of a top view of the first layer of one cell (cell 3) of the metamaterial structure. FIG. 7 is a diagram illustrating an example of a top view of one cell (cell 3) of the metamaterial structure. FIG. 8 is a diagram illustrating an example of an equivalent circuit of a cell. FIG. 9 is a diagram illustrating an example of a graph of the reflection characteristic (S11) and the attenuation characteristic (S21) of the cell 1 illustrated in FIG. FIG. 10 is a diagram showing an example of a graph of the reflection characteristic (S11) and attenuation characteristic (S21) of the cell 2 shown in FIG. FIG. 11 is a diagram illustrating a configuration example of a millimeter-wave antenna device including a cell.

  Hereinafter, a metamaterial structure and an antenna device according to the present invention will be described with reference to the drawings. The configuration of the embodiment is an exemplification, and the present invention is not limited to the configuration of the disclosed embodiment.

Embodiment
(Configuration example 1)
FIG. 1 is a diagram illustrating an example (cell pattern) of one cell of a metamaterial structure (EBG structure). A cell 1 in FIG. 1 includes a ring-shaped peripheral portion 11 obtained by hollowing out a square smaller than the square, a square-shaped central portion 12 formed inside the peripheral portion 11, a peripheral portion 11 and a central portion 12 And a rectangular connecting portion 13 for connecting the two. A cell 1 in FIG. 1 is a top view of the cell 1.

The peripheral part 11, the center part 12, and the connection part 13 are conductors. For example, a metal such as copper is used as the conductor. The peripheral part 11, the center part 12, and the connection part 13 are electrically connected. The peripheral edge part 11, the central part 12, and the connection part 13 are integrally formed. The peripheral part 11, the central part 12, and the connection part 13 exist on substantially the same plane. The peripheral portion 11, the central portion 12, and the connecting portion 13 are designed to have a desired capacitance C and inductance L depending on a conductor portion and a space portion around the conductor portion. C and L depend on the desired resonant frequency of the cell. A cell design method will be described later. The cell 1 is formed on one surface of a planar dielectric, for example. For example, glass epoxy is used as the dielectric. The cell 1 is formed of copper on one surface of a glass epoxy substrate, for example. A space portion formed by the inside of the peripheral edge portion 11, the central portion 12 and the outside of the connecting portion 13 may be filled with a dielectric (gas or liquid) or may be a vacuum. As the dielectric, a plurality of types of dielectrics having different dielectric constants may be used.

  The peripheral portion 11 has a ring shape obtained by hollowing out a square (inner square) smaller than the square from the square (outer square). Each side of the outer square and each side of the inner square are parallel. The width of the peripheral edge portion 11 is substantially uniform over the entire circumference. The outer shape and inner shape of the peripheral edge portion 11 may be a shape other than a square (for example, a rectangle).

  The central portion 12 has a square shape smaller than the square inside the peripheral edge portion 11 and is disposed inside the peripheral edge portion 11. Each side of the square of the central portion 12 is parallel to any side of the square of the peripheral portion 11. The intersection of the square diagonal lines of the central portion 12 and the intersection of the diagonal lines of the square outside the peripheral edge portion 11 coincide with each other. The shape of the central portion 12 is not limited to the square shown here, and may be other shapes such as a circle.

  The connecting portion 13 has a rectangular shape that connects one side inside the peripheral portion 11 and one side of the central portion 12. The length of the connecting portion 13 in the width direction (the direction from the connecting portion with the peripheral edge portion 11 to the connecting portion with the central portion 12 and the direction perpendicular to the plane) is shorter than the length of one side of the central portion 12. Each side of the rectangle of the connecting portion 13 is parallel to any side of the square of the peripheral portion 11. The connecting portion 13 is connected to the peripheral edge portion 11 at the central portion of one side of the square inside the peripheral edge portion 11. The connecting portion 13 is connected to the central portion 12 at the central portion of one side of the square of the central portion 12. Therefore, the space part formed by the outer side of the center part 12 and the connection part 13, and the inner part of the peripheral part 11 is a ring shape (slit ring shape) having a notch portion. The connecting portion 13 corresponds to a notch portion. The space portion is also referred to as a slot line. That is, in the cell 1, the SRR is formed by the slot line. The shape of the cell 1 is a remaining shape obtained by hollowing out a slit ring shape from a planar square conductor. The shape of the connecting portion 13 is not limited to the rectangle shown here, and may be another shape.

  Here, an example of the size of the cell 1 is given. The size of the cell 1 is not limited to the one shown here, and can be changed according to a desired resonance frequency. The length of one side of the square outside the peripheral edge 11 is 0.9 mm. The length of one side of the square inside the peripheral edge 11 is 0.7 mm. Therefore, the width of the peripheral edge portion 11 is 0.1 mm. Moreover, the length of one side of the square of the center part 12 is 0.3 mm. The width of the connecting portion 13 is 0.1 mm. The shortest distance between the peripheral part 11 and the center part 12 is 0.2 mm. The thickness of the cell 1 is 0.001 mm.

  In the metamaterial structure, a plurality of cells are periodically arranged in one direction or two directions on the plane where the peripheral portion 11, the central portion 12, and the connection portion 13 of the cell 1 exist. In the metamaterial structure, adjacent cells are directly connected and electrically connected. Specifically, the peripheral edge 11 of the cell 1 is electrically connected to the peripheral edge of the adjacent cell. Since the peripheral edge 11 is grounded, it can be electrically connected to the peripheral edge of an adjacent cell.

(Configuration example 2)
2, 3 and 4 are diagrams showing examples of one cell of the metamaterial structure. FIG. 2 is an example of a perspective view of the cell 2. The cell 2 in FIG. 2 has a first layer 10 and a second layer 20. The first layer 10 of the cell 2 is the same as the cell 1 of FIG. The second layer 20 of the cell 2 includes a ring-shaped peripheral portion 21 obtained by hollowing out a square smaller than the square from the square, a square-shaped central portion 22 formed inside the peripheral portion 21, and the peripheral portion 21 and the central portion. 22 and a rectangular connecting portion 23 that connects the two. The outer shape of the first layer 10 and the outer shape of the second layer 20 are square planes, and the size of each square is the same. Further, the first layer 10 and the second layer 20 are arranged so that the respective planes are parallel. Further, when the first layer 10 and the second layer 20 are viewed from the normal direction of the plane of the first layer 10, the positions of the corners of the two squares coincide with each other, and the connection portion 13 and the connection portion 23 do not overlap. .

  The peripheral part 21, the center part 22, and the connection part 23 are conductors. The first layer 10 and the second layer 20 are separated by a predetermined distance. The space between the first layer 10 and the second layer 20 may be a vacuum or may be filled with a dielectric (gas or solid). The first layer 10 and the second layer 20 may be in contact with each other without a gap. The first layer 10 and the second layer 20 are designed to have a desired inductance L and capacitance C depending on a conductor portion and a space portion around the conductor portion. For example, the first layer 10 of the cell 2 is formed on one surface of a planar dielectric, and the second layer 20 is formed on the other surface. At this time, the space between the first layer 10 and the second layer 20 is filled with a dielectric. For example, glass epoxy is used as the dielectric.

  FIG. 3 is a diagram illustrating an example of a top view of the second layer 20 of the cell 2. The peripheral portion 21, the central portion 22, and the connecting portion 23 of the second layer 20 of the cell 2 have the same configuration as the peripheral portion 11, the central portion 12, and the connecting portion 13 of the first layer 10. However, the width of the peripheral portion 21 of the second layer 20 is smaller than the width of the peripheral portion 11. Further, the length of one side of the square of the central portion 22 of the second layer 20 is longer than the length of one side of the square of the central portion 12.

  FIG. 4 is a view of the cell 2 as viewed from the normal direction of the plane of the first layer 10 (second layer 20). 4A is a view as seen from the first layer 10 side, and FIG. 4B is a view as seen from the second layer 20 side. In FIG. 4A, the central portion 22 and the connecting portion 23 of the second layer 20 are visible in the back of the first layer 10. In FIG. 4B, the peripheral edge portion 11 and the connection portion 13 of the first layer 10 are visible in the back of the second layer 20.

  Here, an example of the size of the cell 2 is given. The size of the cell 2 is not limited to the one shown here, and can be changed according to desired characteristics. The sizes of the peripheral portion 11, the central portion 12, and the connecting portion 13 of the first layer 10 are the same as those of the cell 1. The length of one side of the square outside the peripheral edge 21 of the second layer 20 is 0.9 mm. The length of one side of the square inside the peripheral edge 21 is 0.8 mm. Therefore, the width of the peripheral portion 21 is 0.05 mm. Moreover, the length of one side of the square of the center part 22 is 0.4 mm. The width of the connection part 23 is 0.1 mm. The shortest distance between the peripheral part 21 and the center part 22 is 0.2 mm. The thickness of the first layer 10 and the second layer 20 is 0.001 mm. The distance between the first layer 10 and the second layer 20 is 0.05 mm.

(Configuration example 3)
5, 6 and 7 are diagrams showing examples of one cell of the metamaterial structure. FIG. 5 is an example of a perspective view of the cell 3. The cell 3 in FIG. 5 has a first layer 30 and a second layer 20. The second layer 20 of the cell 3 is the same as the second layer 20 of the cell 2 in FIG.

  The first layer 30 of the cell 3 has a shape in which a square smaller than the square is cut out from a square (outer square), and a rectangle connected to a small square cut out from a central portion of one side of the outer square is cut out. . The shape of the first layer 30 of the cell 3 is similar to the shape of the space surrounded by the inside of the peripheral edge 11 and the outside of the central portion 12 and the connecting portion 13 in the cell 1. However, the size of the first layer 30 of the cell 3 is different from the size of the space of the cell 1. The first layer 30 of the cell 3 has a ring shape having a notch portion. The first layer 30 of the cell 3 is a split ring made of a conductor. The hollowed out rectangular portion corresponds to a cutout portion (split portion) in the split ring. The first layer 30 is not grounded.

  Further, the first layer 30 and the second layer 20 are arranged so that the respective planes are parallel to each other. Further, when the first layer 30 and the second layer 20 are viewed from the normal direction of the plane of the first layer 30, the positions of the corners of the square outside the first layer 30 and the peripheral portion 21 of the second layer 20. The positions of the corners of the inner square coincide, and the rectangular portion of the first layer 30 and the connecting portion 23 do not overlap. The first layer 30 and the second layer 20 are separated by a predetermined distance. The space between the first layer 30 and the second layer 20 may be vacuum or filled with a dielectric. The first layer 30 and the second layer 20 may be in contact with each other without a gap. The first layer 30 and the second layer 20 are designed to have a desired capacitance C and inductance L depending on the conductor portion and the space around the conductor portion. The first layer 30 is not grounded. For example, the first layer 30 of the cell 3 is formed on one surface of a planar dielectric, and the second layer 20 is formed on the other surface. At this time, the space between the first layer 30 and the second layer 20 is filled with a dielectric. For example, glass epoxy is used as the dielectric.

  FIG. 6 is a diagram illustrating an example of a top view of the first layer 30 of the cell 3. The first layer 30 forms a ring (split ring) including a notch by a hollowed square shape in the central portion and a hollow rectangular shape that connects the square in the central portion and the outer frame. The outer shape of the first layer 30 is smaller than the outer shape of the second layer 20. The first layer 30 is a conductor.

  FIG. 7 is a view of the cell 3 as viewed from the normal direction of the plane of the first layer 30 (second layer 20). FIG. 7A is a view seen from the first layer 30 side, and FIG. 7B is a view seen from the second layer 20 side. In FIG. 7A, the central portion 22 and the connecting portion 23 of the second layer 20 are visible in the back of the first layer 30. In FIG. 7B, the first layer 30 is visible behind the second layer 20.

  Here, an example of the size of the cell 3 is given. The size of the cell 3 is not limited to the one shown here and can be changed according to desired characteristics. The sizes of the peripheral portion 21, the central portion 22, and the connecting portion 23 of the second layer 20 are the same as those of the second layer 20 of the cell 2. The length of one side of the outer square of the first layer 30 is 0.8 mm. The length of one side of the square inside the first layer 30 is 0.2 mm. Therefore, the length of the width of the ring of the first layer 30 is 0.3 mm. Moreover, the length of the width | variety of the cut-out rectangular shape which connects a center part and outer periphery is 0.1 mm. The thickness of the first layer 30 and the second layer 20 is 0.001 mm. The distance between the first layer 30 and the second layer 20 is 0.05 mm.

  Here, the second layer 20 of the cell 3 has the same size as the second layer 20 of the cell 2, but the second layer 20 of the cell 3 has the same size as the first layer 10 of the cell 2. There may be.

In the configuration example 2 and the configuration example 3, the cell has two layers, but may have three or more layers.
The matters described in each of the above configuration examples can be combined as much as possible.

(Design method)
A cell design method (a method for determining a cell size) will be described.
FIG. 8 is a diagram illustrating an example of an equivalent circuit of a cell. As shown in FIG. 8, the equivalent circuit of the cell is represented by a grounded coil and a capacitor connected to the coil. In the cell, the capacitor is formed, for example, between the peripheral conductor and the central conductor, between the first layer conductor and the second layer conductor, or the like. In the cell, the coil is formed on a conductor such as a central portion, a connecting portion, or a peripheral portion, for example. A cell is connected in series with an adjacent cell.

  The resonance frequency f of the equivalent circuit of FIG. 8 is obtained as follows.

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Here, L is the inductance L of the coil, and C is the capacitance C of the capacitor. From this equation, the product of L and C with respect to the desired resonance frequency f is obtained.

  The relationship between the cell shape, the capacitance C of the capacitor, and the inductance L of the coil is expressed as follows.

Here, l is the length of the conductor, W is the width of the conductor, H is the height of the conductor, ε is the dielectric constant between conductors (8.85 × 10 ⁻¹² if vacuum), S is the conductor area, d Is the width between conductors (dielectric thickness). Based on these equations, it is possible to determine the size of the cell having the desired resonance frequency f. The cell size can also be changed by changing the dielectric constant between conductors (changing the dielectric between conductors).

  With the cell size shown in each of the above configuration examples, a metamaterial structure that exhibits effective characteristics in the 70 GHz band can be realized.

(Characteristic)
FIG. 9 is a diagram illustrating an example of a graph of the reflection characteristic (S11) and the attenuation characteristic (S21) of the cell 1 illustrated in FIG. The horizontal axis of the graph of FIG. 9 is the frequency, and the vertical axis is the reflection characteristic for S11 and the transmission characteristic for S21. As the value on the vertical axis is larger, the electromagnetic wave is reflected (S11) and passes (S21). In the graph of FIG. 9, since the attenuation characteristic and reflection characteristic are low and gentle in the vicinity of 76 GHz, the cell 1 is effectively applied in a wide band. Because of this characteristic, unnecessary radiation such as spurious is also attenuated. Therefore, a metamaterial structure is arranged between the antennas, which is effective for securing isolation between the antennas. The cell 1 suppresses reflection and passage of electromagnetic waves in a wide band.

FIG. 10 is a diagram showing an example of a graph of the reflection characteristic (S11) and attenuation characteristic (S21) of the cell 2 shown in FIG. The horizontal axis of the graph of FIG. 10 is the frequency, and the vertical axis is the reflection characteristic for S11 and the transmission characteristic for S21. In the graph of FIG. 10, the attenuation characteristic and the reflection characteristic decrease rapidly in the vicinity of 76 GHz. Therefore, it can be seen that the cell 2 has a narrow band and is effective in the desired band. That is, the transmission wave near 76 GHz from the antenna is easily absorbed and hardly reflected by the metamaterial structure including the cell 2. By utilizing this characteristic and mounting the metamaterial structure including the cell 2 on the edge of the substrate having the antenna, unnecessary reflection of the transmission wave from the antenna can be suppressed. The cell 2 suppresses reflection and passage of electromagnetic waves particularly near 76 GHz. Cell 3 is the same as cell 2.

(Antenna device)
FIG. 11 is a diagram illustrating a configuration example of a millimeter-wave antenna device including a cell. The antenna device 100 of FIG. 11 includes a first antenna 110, a second antenna 120, and a metamaterial structure 130. The first antenna 110, the second antenna 120, and the metamaterial structure 130 are provided on substantially the same plane (substrate). The metamaterial structure 130 is disposed around the first antenna 110, around the second antenna 120, and between the first antenna 110 and the second antenna 120. The metamaterial structure 130 may be disposed around the first antenna 110, around the second antenna 120, or between the first antenna 110 and the second antenna 120. On the right side of FIG. 11, a portion of the metamaterial structure 130 is shown enlarged.

  The first antenna 110 is, for example, a transmission antenna that transmits millimeter waves. The second antenna 120 is a receiving antenna that receives millimeter waves, for example. The first antenna 110 and the second antenna 120 are, for example, pattern antennas formed on one surface of a dielectric substrate (planar dielectric, dielectric plate, eg, epoxy glass substrate). The first antenna 110 and the second antenna 120 may be formed on different surfaces. The first antenna 110 and the second antenna 120 are made of metal such as copper.

  In the metamaterial structure 130, the cells (cell 1, cell 2, or cell 3) are adjacent to each other over the range of the metamaterial structure 130 in the first direction and the second direction (in FIG. 11, the x direction and the y direction). ) Spatially and periodically. The metamaterial structure 130 is formed on a dielectric substrate on which the first antenna 110 and the second antenna 120 are formed. In the example of FIG. 11, the x direction in which cells are periodically arranged and the y direction are orthogonal to each other, but the first direction and the second direction in which cells are periodically arranged may not be orthogonal to each other. Good. In addition, adjacent cells are connected to each other at the periphery of the cell without any gap. Therefore, adjacent cells are electrically connected. The periphery of the metamaterial structure 130 is grounded. Since the periphery of the metamaterial structure 130 is grounded, the periphery of each cell is grounded. When the metamaterial structure 130 has a two-layer structure as in the above configuration example 2 or configuration example 3, the first layer is formed on one surface of the dielectric substrate, and the second layer is formed on the other surface. Is done. At this time, the first antenna 110 and the second antenna are formed on one surface or the other surface of the dielectric substrate. The cells in the metamaterial structure 130 may all have the same shape or may include different shapes.

  For example, when the metamaterial structure 130 does not exist, the radio wave emitted from the first antenna 110 goes directly to the second antenna 120 and interferes with the original received radio wave of the second antenna. In the antenna device 100, by including the metamaterial structure 130, the wraparound of the radio wave transmitted from the first antenna 110 to the second antenna 120 is reduced. That is, interference between antennas is suppressed. Moreover, since the component which the electromagnetic wave transmitted from the 1st antenna 110 reflects by the metamaterial structure 130 is small, it can suppress that self-transmission power interferes in the 1st antenna 110. FIG. Further, the metamaterial structure 130 can suppress radiation from the edge of the dielectric substrate.

  Further, in the conventional SRR cell, since the conductor portion is not grounded, it is required to provide a space around the cell. For this reason, in the metamaterial structure by the cell by the conventional SRR, it was difficult to make installation space small. In the metamaterial structure 130 in which cells having peripheral portions as described above are periodically arranged, since the peripheral portions of the respective cells are grounded, adjacent cells can be brought into contact with each other at the peripheral portions. For this reason, the space which a cell arrange | positions can be made small. The metamaterial structure 130 is effective for antenna isolation.

(Operation and effect of the embodiment)
The metamaterial structure of the present embodiment realizes the SRR in the cell by a slit ring shape by a space portion (slot line) surrounded by the peripheral portion, the central portion, and the connecting portion. Since the SRR by the conductor of the conventional cell is not grounded, it is required to make a space between adjacent cells. However, in the SRR by the space portion of this embodiment, the conductor portion around the SRR is grounded, It is not necessary to leave an interval. Therefore, by realizing the SRR by the space portion, the cell density can be improved as compared with the case where the SRR is realized by a conductor. For example, by increasing the cell density, more cells can be arranged between antennas, and signal interference between antennas can be suppressed. Further, by arranging the cell around the antenna, reflection due to grounding of the edge of the substrate can be suppressed. That is, the metamaterial structure of this embodiment can realize an antenna device with better attenuation characteristics and reflection characteristics. In addition, since the cell density is improved, the mounting area of the antenna device 100 can be reduced.

  According to the metamaterial structure of the present embodiment, as in the configuration example 2 and the configuration example 3, the capacitance C can be formed between the layers by making the cell into two layers. It can be realized with an appropriate size.

  In a pattern antenna such as a millimeter wave, a plurality of planar antennas are formed on one surface of the same circuit board, so that the planar antennas are close to each other, and mutual interference between the planar antennas becomes a problem. In the antenna device 100 of this embodiment, since the metamaterial structure of this embodiment is disposed between two antennas, interference between antennas can be suppressed.

1 Metamaterial structure cell
2 Metamaterial structure cell
3 Metamaterial structure cells
10 1st layer
11 Perimeter
12 Central part
13 connections
20 Second layer
21 Edge
22 Central part
23 Connection
30 1st layer
100 Antenna device
110 First antenna
120 Second antenna
130 Metamaterial structure

Claims (6)

A metamaterial structure in which a plurality of cells are periodically arranged,
The cell is
A ring-shaped first peripheral portion, a first central portion disposed inside the first peripheral portion,
Including a first layer having a first connection portion connecting the first peripheral edge portion and the first central portion;
Metamaterial structure. The cell is
A ring-shaped second peripheral portion, a second central portion disposed inside the second peripheral portion,
A second layer having a second connection portion connecting the second peripheral edge portion and the second central portion;
The metamaterial structure according to claim 1, wherein the first layer and the second layer are parallel. A second layer having a ring-shaped split ring portion including a notch,
The metamaterial structure according to claim 1, wherein the first layer and the second layer are parallel. Including a flat dielectric plate;
The metamaterial structure according to claim 2 or 3, wherein the first layer is formed on one surface of the dielectric plate, and the second layer is formed on the other surface of the dielectric plate. The cell is electrically connected to an adjacent cell;
The metamaterial structure according to any one of claims 1 to 4. A flat dielectric plate;
A first antenna formed on the dielectric plate;
A second antenna formed on the dielectric plate;
In the dielectric plate, including the metamaterial structure according to any one of claims 1 to 5 formed between the first antenna and the second antenna.
Antenna device.

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