Antenna system

Abstract

An antenna system (10) comprises: an antenna (20); and a metasurface (40) configured so as to change between a transmissive state of transmitting electromagnetic waves transmitted or received by the antenna (20) and a non-transmissive state of not transmitting the electromagnetic waves. The antenna system (10) further comprises a controller (60) that controls a first portion of the metasurface (40) to the transmissive state and controls a second portion other than the first portion of the metasurface (40) to the non-transmissive state. By having this configuration, it is possible to control, using the metasurface (40), the direction in which the electromagnetic waves emitted by the antenna (20) are transmitted and the direction of the electromagnetic waves that can be incident on the antenna (20).

Description

Antenna System

[0001] The present invention relates to an antenna system.

[0002] One type of metamaterial is a plate-shaped metasurface with two-dimensionally arranged resonant cells. Non-Patent Document 1 discloses a metasurface that uses resonant cells in which a dielectric with a variable dielectric constant (a liquid crystal layer in Non-Patent Document 1) is sandwiched between opposing metal patterns.

[0003] Jun Yang, et al., “Electrically tunable liquid crystal terahertz device based on double-layer plasmonic metamaterial”, Optics Express, vol.27, No.19, pp.27039-27045, 2019

[0004] Non-Patent Document 1 discloses a transmission type metasurface, but does not disclose its specific application. The inventors of the present application have discovered that a metasurface can be used to control the direction in which an electromagnetic wave emitted by an antenna is transmitted or the direction in which an electromagnetic wave can be incident on an antenna.

[0005] The present invention aims to use a metasurface to control the direction in which electromagnetic waves emitted by an antenna are transmitted or the direction in which electromagnetic waves can be incident on an antenna.

[0006] The antenna system of the present invention comprises an antenna, a metasurface configured to change between a transparent state in which electromagnetic waves transmitted or received by the antenna are transmitted and a non-transparent state in which electromagnetic waves are not transmitted, and a controller that controls a first portion of the metasurface to the transparent state and a second portion of the metasurface other than the first portion to the non-transparent state.

[0007] According to the present invention, the direction in which the electromagnetic waves emitted by the antenna are transmitted or the direction in which the electromagnetic waves can be incident on the antenna can be controlled using a metasurface.

[0008] FIG. 1 is a diagram illustrating the configuration of an antenna system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the configuration of a first surface of a metasurface. FIG. 3 is a diagram illustrating the first and second conductive patterns and the first to fourth wirings in portion A of the metasurface in FIG. 2, viewed from the -Z direction. FIG. 4 is a cross-sectional view of portion A taken along line B-B in FIG. 3. FIG. 5 is a diagram illustrating the first substrate, first conductive pattern, and first and second wirings in portion A, viewed from the -Z direction. FIG. 6 is a diagram illustrating the second substrate, second conductive pattern, and third and fourth wirings in portion A, viewed from the +Z direction. FIG. 7 is a graph illustrating the frequency characteristics of the transmission intensity and reflection intensity (S parameters) of electromagnetic waves of the resonant cell in FIG. 3. FIG. 8 is a diagram illustrating an example of the configuration of a table referenced when determining the surface to be in the transmission state. FIG. 9 is a conceptual diagram illustrating the antenna system viewed from above, illustrating the positional relationship between the electromagnetic waves emitted by the antenna and the transmission-state portions of the metasurface. Fig. 10 is a conceptual diagram of the antenna system viewed from above, showing the positional relationship between the electromagnetic waves emitted by the antenna and the transmissive portions of the metasurface. Fig. 11 is a conceptual diagram of the antenna system viewed from above, showing the positional relationship between the electromagnetic waves emitted by the antenna and the transmissive portions of the metasurface. Fig. 12 is a conceptual diagram of the antenna system viewed from above, showing an example of moving the transmissive portions of the metasurface. Fig. 13 is a conceptual diagram of the antenna system viewed from above, showing an example of moving the transmissive portions of the metasurface. Fig. 14 is a conceptual diagram of the antenna system viewed from above, showing an example of moving the transmissive portions of the metasurface.

[0009] The antenna system according to the present embodiment will be described below with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals. In addition, in some cases, only some of the same elements are denoted by the same reference numerals.

[0010] The antenna system 10 according to this embodiment shown in FIG. 1 is configured as a system that transmits and receives electromagnetic waves of a specific frequency using an antenna 20. The specific frequency is, for example, any frequency in the range of 3 GHz to 3 THz used in 5G or 6G communications. Note that the term "specific frequency" refers to not only a single frequency but also a frequency band. Hereinafter, electromagnetic waves in a specific frequency band will also be simply referred to as electromagnetic waves. The antenna system 10 controls the direction of electromagnetic waves emitted from or incident on the antenna 20.

[0011] The antenna system 10 includes an antenna 20, a transceiver 30, a metasurface 40, and a controller 60. In the following description, the central axis direction of the metasurface 40 is referred to as the up-down direction, and the direction in which a horizontal plane perpendicular to the up-down direction extends (front-back and left-right directions) is referred to as the horizontal plane direction.

[0012] The antenna 20 is a non-directional antenna, and in this example, is a dipole antenna. As a dipole antenna, the antenna 20 has isotropy and no directivity in the horizontal plane. A non-directional antenna is an antenna that does not have directivity in at least one plane. The antenna 20 converts the received electromagnetic waves into electrical signals. The converted electrical signals are supplied to the transceiver 30. The antenna 20 converts the electrical signals from the transceiver 30 into electromagnetic waves that are radiated from the antenna 20.

[0013] The transceiver 30 performs processes such as amplification, demodulation, and filtering on the electrical signal from the antenna 20 to extract the data carried by the electromagnetic waves and supplies the extracted data to the controller 60. The transceiver 30 generates an electrical signal in which the data from the controller 60 is carried on a carrier wave and supplies the generated electrical signal to the antenna 20.

[0014] The metasurface 40 is configured to be switchable between a transparent state in which electromagnetic waves are transmitted and a non-transparent state in which electromagnetic waves are not transmitted under the control of the controller 60. The non-transparent state includes a reflective state in which electromagnetic waves are reflected and an absorbing state in which electromagnetic waves are absorbed.

[0015] The metasurface 40 has flat plate-like first to sixth surfaces 41 to 46, which respectively constitute the faces of the hexagonal cylinder. In this embodiment, any of the first to sixth surfaces 41 to 46 is in a transparent state, and the remaining surfaces are in a non-transparent state.

[0016] Each of the first surface 41 to the sixth surface 46 has the same structure. Below, the structure of the first surface 41 will be described as a representative of these structures. In the following description, the thickness direction of the first surface 41 is referred to as the Z direction. Two directions that are perpendicular to the Z direction and perpendicular to each other are referred to as the X direction and the Y direction, respectively.

[0017] As shown in FIG. 1 , the first surface 41 includes a plurality of resonant cells RC arranged in a matrix in the X and Y directions. The resonant cells RC are formed with dimensions smaller than the wavelength of the electromagnetic wave. The dimensions refer to, for example, the lengths of the resonant cells RC in the X and Y directions when viewed from the Z direction. The first surface 41 also includes drive circuits 59A and 59B (described in detail below).

[0018] As shown in Figures 3 to 5, the first surface 41 has a laminated structure including a first substrate 51, a second substrate 52, a plurality of first conductive patterns 53, a plurality of second conductive patterns 54, a plurality of first wirings 55A, a plurality of second wirings 55B, a plurality of third wirings 56A, a plurality of fourth wirings 56B, and a dielectric layer 57.

[0019] The first substrate 51 and the second substrate 52 are flat and face each other in the Z direction. The substrates 51 and 52 are insulating substrates made of a dielectric material such as a glass substrate.

[0020] The first conductive pattern 53, together with first wiring 55A and second wiring 55B, is provided on the first substrate 51. The second conductive pattern 54, together with third wiring 56A and fourth wiring 56B, is provided on the second substrate 52. The conductive patterns 53 and 54 are formed of a low-resistance metal material such as copper. The wirings 55A, 55B, 56A, and 56B are made of transparent electrodes such as ITO (Indium Tin Oxide).

[0021] The conductive patterns 53 and 54 are arranged in a matrix in the X and Y directions and correspond one-to-one to each other.

[0022] The wirings 55A and 55B extend in the Y direction. Each of the first wirings 55A electrically connects two of the first conductive patterns 53 adjacent to each other in the Y direction. Each of the second wirings 55B electrically connects each of the multiple first conductive patterns 53 arranged in the X direction at the end in the -Y direction to the drive circuit 59A.

[0023] The wirings 56A and 56B extend in the X direction. Each of the third wirings 56A electrically connects two of the second conductive patterns 54 adjacent to each other in the Y direction. Each of the fourth wirings 56B electrically connects each of the second conductive patterns 54 arranged in the Y direction at the end in the -X direction to the drive circuit 59A.

[0024] The dielectric layer 57 is sandwiched between the first substrate 51 and the second substrate 52. The dielectric layer 57 has a variable dielectric constant. Here, the dielectric constant changes depending on the applied voltage. The dielectric layer 57 is made of liquid crystal, is filled between the substrates 51 and 52, and is sealed with a sealing member (not shown). In FIG. 4, the dielectric layer 57 is represented by a diagram in which some liquid crystal molecules are exaggerated.

[0025] In this embodiment, each resonant cell RC is composed of a pair of conductive patterns 53 and 54 facing each other in the Z direction, and a dielectric 57A, which is a portion of the dielectric layer 57 sandwiched between the conductive patterns 53 and 54. The pair of conductive patterns 53 and 54 are formed in different shapes and are formed in shapes that partially overlap when viewed from the Z direction. The dielectric 57A is a portion sandwiched between the overlapping portions of the conductive patterns 53 and 54.

[0026] The resonant structure of the resonant cell RC is an LC resonant structure having an inductive component L[H] and a capacitive component C[F], and reflects electromagnetic waves in a frequency band including a resonant frequency fr corresponding to the component LC and frequencies in the vicinity thereof. The resonant frequency fr is calculated by the following formula (1): fr=1 / (2π√(L·C)) (1)

[0027] The inductive component L is a fixed value resulting from the shapes of the conductive patterns 53 and 54. On the other hand, the capacitive component C varies depending on the dielectric constant of the dielectric 57A sandwiched between the overlapping portions of the conductive patterns 53 and 54. The dielectric constant varies depending on the potential difference between the pair of conductive patterns 53 and 54, i.e., the applied voltage. In this embodiment, the transmittance of electromagnetic waves of a specific frequency is changed by applying or not applying a voltage to the pair of conductive patterns 53 and 54.

[0028] FIG. 7 shows the results of an electromagnetic field analysis simulation in which the substrates 51 and 52 are made of alkali-free glass, the conductive patterns 53 and 54 are made of copper, and the wiring 55A, 55B, 56A, and 56B are made of ITO. Here, the frequency characteristics of the transmittance and reflectance of the resonant cell RC when a predetermined voltage is applied and the transmittance and reflectance of the resonant cell RC when no voltage is applied were simulated. As can be seen from FIG. 7 , in the frequency band of 110 GHz to 115 GHz, the transmittance is higher and the reflectance is lower when a predetermined voltage is applied than when no voltage is applied. Therefore, the state of the resonant cell RC can be switched between a transparent state and a non-transparent state for electromagnetic waves by applying or not applying a voltage. Note that the non-transparent state may be a state in which the transmittance of electromagnetic waves is lower than that of the transparent state, and does not necessarily have to be a state in which the electromagnetic waves are completely blocked. The frequency of the electromagnetic waves to be transmitted or blocked can be adjusted by adjusting the shape (including size) of the conductive patterns 53 and 54.

[0029] The driving circuit 59A supplies a potential to each of the first conductive patterns 53 in one row aligned in the X direction via wirings 55A and 55B. The driving circuit 59B supplies a potential to each of the second conductive patterns 54 in one column aligned in the Y direction via wirings 56A and 56B. The driving circuits 59A and 59B are controlled by a controller 60.

[0030] The controller 60 controls the supply potential for each column and row via the drive circuits 59A and 59B. This controls the potential difference between the conductive patterns 53 and 54, i.e., the applied voltage, for each resonant cell RC. In this embodiment, the controller 60 supplies a reference potential to the first conductive pattern 53 of each row via the drive circuit 59A. The drive circuit 59A may be a wiring that connects the wiring 55B of each row to ground. When the first surface 41 is to be in the transmissive state, the controller 60 supplies a predetermined potential corresponding to the applied voltage that causes the resonant cell RC to be in the transmissive state to the second conductive pattern 54 of each column via the drive circuit 59B. This applies the predetermined voltage that causes the resonant cell RC to be in the transmissive state to the conductive patterns 53 and 54 of the resonant cell RC. When the first surface 41 is to be in the non-transmissive state, the controller 60 supplies the reference potential (i.e., no voltage is applied).

[0031] The controller 60 includes a processing unit 61 and a memory 62 .

[0032] The processing unit 61 is a circuit that includes at least one of, for example, one or more processors such as a CPU (Central Processing Unit) that executes a program stored in the memory 62, one or more ASICs (Application Specific Integrated Circuits), and one or more FPGAs (Field-Programmable Gate Arrays).

[0033] When the processing unit 61 includes a processor, the memory 62 stores a program to be executed by the processor. The memory 62 also stores data necessary for the processing performed by the processing unit 61. For example, the memory 62 stores a table (see FIG. 8 ) showing the correspondence between the transmission direction and the surface to be set in the transparent state. The memory 62 includes a non-volatile memory and a main memory of the processing unit 61.

[0034] The processing unit 61 receives, for example, a set of current transmission data and data on the transmission direction in which the transmission data is transmitted as electromagnetic waves from an external device (not shown).

[0035] The processing unit 61 references the table in the memory 62 based on the supplied transmission direction data and acquires the surface corresponding to the transmission direction. The controller 60 applies a predetermined voltage to each resonant cell RC of the surface acquired from the table, among the first surface 41 to the sixth surface 46, to control the surface to a transparent state. The controller 60 does not apply a voltage to the resonant cells RC of the remaining surfaces, leaving the remaining surfaces in a non-transparent state. In the following description, the transmission direction is the fourth direction, and the fourth surface 44 is in a transparent state.

[0036] The processing unit 61 supplies the transmission data provided above to the transceiver 30. The transceiver 30 transmits electromagnetic waves representing the transmission data from the antenna 20. As shown in FIG. 9 , among the electromagnetic waves radiated from the antenna 20, those that reach the fourth surface 44 in the transparent state (represented by dotted lines) (schematically indicated by arrows EM; the same applies to FIGS. 10 and 11 ) pass through the fourth surface 44 and are emitted to the outside of the metasurface 40. Those that reach the first surface 41 to the third surface 43 and the fifth surface 45 to the sixth surface 46 in the non-transparent state (represented by solid lines) do not pass through these surfaces (are reflected by these surfaces) and are not emitted to the outside of the metasurface 40. As a result, the electromagnetic waves are transmitted in the fourth direction, which is the direction of the fourth surface 44. The phrase "electromagnetic waves not emitting to the outside of the metasurface 40" also includes a state in which less electromagnetic waves are emitted than from the surfaces in the transparent state.

[0037] The direction of arrival of the electromagnetic waves received by the antenna 20 (the direction of the electromagnetic wave emission source) may be limited. In such a case, the processing unit 61 receives the directions of arrival of the electromagnetic waves (first to sixth directions) that are permitted for reception from an external device (not shown). The processing unit 61 obtains the surface corresponding to the supplied direction of arrival from the table of FIG. 8 and controls the obtained surface to a transparent state. In this case, the transmission direction in the table becomes the direction of arrival.

[0038] The processing unit 61 may set multiple surfaces among the first surface 41 to the sixth surface 46 to the transmissive state, rather than just one surface. In such cases, multiple directions are specified by the external device or the like. The multiple surfaces controlled to the transmissive state may be adjacent, continuous surfaces, or may be separate surfaces. As shown in FIG. 10 , the processing unit 61 may control one surface among the first surface 41 to the sixth surface 46 (the fourth surface 44 in FIG. 10 ) to the non-transmissive state (here, the reflective state; the reflected wave is also schematically indicated by the arrow EM1), and control the remaining five surfaces to the transmissive state.

[0039] The processing unit 61 may control only a portion of one surface to be in the transparent state (see FIG. 11 ). In this case, the directionality of the electromagnetic waves emitted from the metasurface 40 is increased. The processing unit 61 also acquires information on which portion of the surface to be in the transparent state from the external device or the like. This information may be determined based on the transmission direction. In this case, the table in FIG. 8 shows the relationship between the detailed transmission direction, the surface to be controlled to be in the transparent state at that time, and its range. The size of the range to be in the transparent state may be variable. In other words, the processing unit 61 may control the size of the portion to be in the transparent state (the range of the portion in the transparent state). The processing unit 61 applies the predetermined voltage to some of the resonant cells RC. The portion to be in the transparent state may extend from the upper end to the lower end of the metasurface, or may be a partial region in the vertical and radial directions. In the latter case, the processing unit 61 controls the application of voltage to each of the resonant cells RC by individually supplying potentials to each column and each row via the driving circuits 59A and 59B.

[0040] As described above, the antenna system 10 includes the antenna 20 and the metasurface 40 configured to change between a transparent state that transmits electromagnetic waves transmitted or received by the antenna 20 and a non-transparent state that does not transmit the electromagnetic waves. The antenna system 10 further includes a controller 60 that controls a first portion of the metasurface 40 (e.g., at least one of the first surface 41 to the sixth surface 46) to a transparent state and a second portion of the metasurface 40 other than the first portion to a non-transparent state. This configuration allows the metasurface 40 to control the direction in which the electromagnetic waves emitted by the antenna 20 are transmitted and the direction in which electromagnetic waves can be incident on the antenna 20. This allows the antenna system 10 to function as a directional antenna. Furthermore, the direction of the directivity is also controlled. While it is conceivable to control the direction of the directivity by mechanically changing the orientation of the directional antenna, this has the disadvantage of requiring a long time to rotate the directional antenna. Furthermore, this also has the disadvantage of increasing the weight of the system and shortening its lifespan due to mechanical wear. In this embodiment, the directivity can be controlled by dynamically controlling the metasurface 40, thereby suppressing the above-mentioned disadvantages. The first and second portions may be composed of multiple regions separated from each other. The antenna system 10 may be configured exclusively for receiving or transmitting electromagnetic waves. In this case, the transceiver 30 serves as a receiver or a transmitter.

[0041] The controller 60 (processing unit 61) may be configured to switch between making all of the first surface 41 to the sixth surface 46 transparent and making only some of the first surface 41 to the sixth surface 46 transparent. This allows the antenna system 10 to function as a directional antenna or a non-directional antenna (particularly, an isotropic antenna). The controller 60 (processing unit 61) may further control all of the first surface 41 to the sixth surface 46 to be opaque. This allows electromagnetic waves transmitted by the antenna 20 or electromagnetic waves received by the antenna 20 to be blocked by a member other than the antenna 20.

[0042] The metasurface 40 may have a polygonal cylindrical shape other than a hexagonal cylindrical shape or a cylindrical shape. By forming the metasurface 40 into a cylindrical shape, the antenna 20 can be easily placed within the metasurface 40 through openings at both ends. The metasurface 40 does not have to have a shape that surrounds the antenna 20 360 degrees when viewed from above and below. For example, the metasurface 40 may have a shape that surrounds the antenna 20 60 degrees, 120 degrees, 180 degrees, or 270 degrees. The metasurface 40 may be formed in a polyhedral or spherical shape with a cavity in which the antenna 20 is placed. The metasurface 40 may be composed of multiple metasurfaces that are spaced apart from each other. For example, the first surface 41 to the sixth surface 46 may be spaced apart from each other. The metasurface 40 may have a shape that combines flat and curved surfaces.

[0043] When the metasurface 40 is cylindrical, the antenna 20 may have isotropy in the direction of the plane perpendicular to the central axis of the metasurface, as described above. This allows directivity to be easily obtained by making a portion of the circumferential direction of the metasurface 40 transparent. The antenna 20 may be any antenna. As another example, the antenna 20 may include multiple directional antennas and function as an isotropic antenna as a whole.

[0044] The direction of the electromagnetic wave that can be incident on the antenna 20 can be controlled using the metasurface 40, thereby enabling the direction of the electromagnetic wave to be identified. This example will be described below. In the following, it is assumed that electromagnetic waves representing predetermined data repeatedly arrive at the antenna system 10.

[0045] As shown in FIG. 12 , the processing unit 61 of the controller 60 first sets all of the first surface 41 to the sixth surface 46 to a transparent state. The processing unit 61 detects that the electromagnetic waves have been received by the antenna 20 when the predetermined data (data extracted from the electromagnetic waves) is supplied from the transceiver 30 (or the receiver). The electromagnetic waves may be, for example, reflected waves from an object in a radar. In such a case, the transceiver 30 (receiver) may supply the controller 60 with information indicating that the electromagnetic waves have been received by the antenna 20. The processing unit 61 may detect that the electromagnetic waves have been received by the antenna 20 when the information is supplied.

[0046] Here, the direction of the arrow A1, which schematically illustrates the electromagnetic wave in FIG. 12 , is the arrival direction of the electromagnetic wave. However, when the first surface 41 to the sixth surface 46 are all in the transparent state, the arrival direction of the electromagnetic wave is unknown. Therefore, the processing unit 61 scans the electromagnetic wave by sequentially setting the first surface 41 to the sixth surface 46 in the transparent state one by one. When the processing unit 61 detects reception of the electromagnetic wave during this scan, it detects the position of the surface that is in the transparent state at that time. The detected position corresponds to the arrival direction of the electromagnetic wave. Based on this detected position, the processing unit 61 detects the direction from that position toward the antenna 20 as the arrival direction of the electromagnetic wave at the antenna 20. In the example of FIG. 12 , the processing unit 61 detects that the electromagnetic wave is received by the antenna 20 when the fifth surface 45 is in the transparent state, so the processing unit 61 detects the direction from the fifth surface 45 as the arrival direction of the electromagnetic wave at the antenna 20. The processing unit 61 may output the detection result to the outside of the antenna system 10 .

[0047] The processing unit 61 may further set only a portion of the surface at the detected position, i.e., the surface that was in a transparent state when the electromagnetic wave was received, to a transparent state, and sequentially move the portion that is in a transparent state within the surface, as shown in Fig. 13. The processing unit 61 may detect the detailed direction of arrival of the electromagnetic wave to the antenna 20 based on the position of the portion where it is detected that the electromagnetic wave has been received by the antenna 20. In Fig. 13, the processing unit 61 sequentially moves the portion R1 in a transparent state within the fifth surface 45.

[0048] As described above, the processing unit 61 may move the first portion of the metasurface 40 that is controlled to be in a transparent state, detect the position of the first portion when the antenna 20 receives the electromagnetic wave, and detect the arrival direction of the electromagnetic wave to the antenna 20 based on the detected position. This makes it possible to detect (estimate) the arrival direction of the electromagnetic wave.

[0049] As described above, the processing unit 61 may move a third portion (e.g., portion R1) that is smaller than the first portion and controlled to be in a transparent state within the range of the first portion at the detected position, detect the position of the third portion when the antenna 20 receives the electromagnetic wave, and detect the arrival direction of the electromagnetic wave to the antenna 20 based on the detected position. This makes it possible to detect the arrival direction in detail.

[0050] Furthermore, when the entire metasurface 40 is controlled to be in a transparent state and the antenna 20 receives electromagnetic waves, the processing unit 61 sets only the first portion of the metasurface 40 in a transparent state and the remaining second portion in a non-transparent state, and starts moving the first portion that is in a transparent state. This allows the arrival of electromagnetic waves to be detected quickly, and the direction of arrival of the electromagnetic waves to be detected smoothly.

[0051] As another example, the processing unit 61 may initially set a portion of the metasurface 40 (which may be a surface unit or a portion within a surface) in a transparent state, set the other portions in a non-transparent state, and sequentially move the transparent portions without changing their size, as shown in Figure 14. This method also allows the direction of arrival of the electromagnetic wave to be detected.

[0052] The processing unit 61 may monitor the reception strength of the electromagnetic waves detected by the transceiver 30 (receiver) while moving the first part and / or the third part, and detect the position of the first part and / or the third part with the highest reception strength as the position of the first part or the third part when the antenna 20 received the electromagnetic waves.

[0053] The present invention is not limited to the above-described embodiments and modifications. For example, the present invention includes various modifications to the above-described embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above-described embodiments and modifications can be combined as appropriate within a range that does not cause contradictions. In addition, any of the above-described configurations can be deleted.

[0054] (Supplementary Notes) Configurations that are examples of the above-described embodiments and modifications are described below. (Supplementary Note 1) An antenna system comprising: an antenna; a metasurface configured to change between a transparent state that transmits electromagnetic waves transmitted or received by the antenna and a non-transparent state that does not transmit electromagnetic waves; and a controller that controls a first portion of the metasurface to the transparent state and a second portion of the metasurface other than the first portion to the non-transparent state. (Supplementary Note 2) The antenna system according to Supplementary Note 1, wherein the metasurface has a cylindrical shape with the antenna disposed inside. (Supplementary Note 3) The antenna system according to Supplementary Note 1 or 2, wherein the antenna has isotropy in a direction extending a plane perpendicular to a central axis of the metasurface. (Supplementary Note 4) The antenna system according to any one of Supplements 1 to 3, wherein the controller further controls the entire metasurface to the transparent state. (Supplementary Note 5) The antenna system according to any one of Supplements 1 to 4, wherein the controller further controls the range of the first portion of the metasurface. (Supplementary Note 6) The antenna system according to any one of Supplements 1 to 5, wherein the antenna is configured to receive the electromagnetic waves, and the controller moves the first portion controlled to the transparent state, detects a position of the first portion when the antenna receives the electromagnetic waves, and detects a direction of arrival of the electromagnetic waves at the antenna based on the detected position. (Supplementary Note 7) The antenna system according to Supplementary Note 6, wherein the controller moves a third portion smaller than the first portion and set to the transparent state within a range of the first portion at the detected position, detects a position of the third portion when the antenna receives the electromagnetic waves, and detects a direction of arrival of the electromagnetic waves at the antenna based on the detected position. (Supplementary Note 8) The antenna system according to Supplementary Note 6 or 7, wherein the controller controls the entire metasurface to a transparent state and starts moving the first portion when the antenna receives the electromagnetic waves.

[0055] 10...antenna system, 20...antenna, 30...transceiver, 40...metasurface, 41...first surface, 42...second surface, 43...third surface, 44...fourth surface, 45...fifth surface, 46...sixth surface, 51...first substrate, 52...second substrate, 53...first conductive pattern, 54...second conductive pattern, 55A...first wiring, 55B...second wiring, 56A...third wiring, 56B...fourth wiring, 57...dielectric layer, 57A...dielectric, 59A...drive circuit, 59B...drive circuit, 60...controller, 61...processing unit, 62...memory, A...portion, R1...portion, RC...resonant cell.

Claims

1. An antenna system comprising: an antenna; a metasurface configured to change between a transparent state that transmits electromagnetic waves transmitted or received by the antenna and a non-transparent state that does not transmit electromagnetic waves; and a controller that controls a first portion of the metasurface to the transparent state and a second portion of the metasurface other than the first portion to the non-transparent state.

2. The antenna system of claim 1, wherein the metasurface is cylindrical with the antenna disposed inside.

3. The antenna system according to claim 2, wherein the antenna has isotropy in a direction in which a plane perpendicular to the central axis of the metasurface extends.

4. The antenna system of claim 1, wherein the controller further controls all of the metasurfaces to be in the transparent state.

5. The antenna system of claim 1, wherein the controller further controls the extent of the first portion of the metasurface.

6. The antenna system according to claim 1, wherein the antenna is configured to receive the electromagnetic waves, and the controller moves the first portion controlled to the transparent state, detects the position of the first portion when the antenna receives the electromagnetic waves, and detects the direction of arrival of the electromagnetic waves at the antenna based on the detected position.

7. The antenna system according to claim 6, wherein the controller moves a third portion, which is smaller than the first portion and is to be in the transparent state, within the range of the first portion at the detected position, detects the position of the third portion when the antenna receives the electromagnetic wave, and detects the direction of arrival of the electromagnetic wave to the antenna based on the detected position.

8. The antenna system of claim 6, wherein the controller controls the entire metasurface to a transparent state and starts moving the first portion when the antenna receives the electromagnetic wave.

Images