Angle amplifier and beamforming device

Abstract

An angle amplifier (12) of this invention is an angle amplifier that a beamformed electromagnetic wave enters at a predetermined steering angle, and includes a plurality of metamaterial-based elements (121_1 to 121_n). The metamaterial-based element is formed by a metamaterial cell and a filling material, the plurality of metamaterial-based elements are arranged point-symmetrical with respect to a center of the angle amplifier, and an exit angle of the electromagnetic wave that exits from the angle amplifier is larger than the predetermined steering angle.　Hence, this invention can provide an angle amplifier capable of amplifying the steering angle of a beamformed incident electromagnetic wave beam.

Description

Angle Amplifier and Beamforming Device

[0001] The present invention relates to an angle amplifier that increases the steering angle of an electromagnetic wave to be beamformed and a beamforming device.

[0002] In high-frequency wireless communication, particularly at a millimeter-wave frequency of 30 to 500 GHz, high free space path losses, that is, atmospheric attenuation in gasses and rainfall, signal attenuation in objects, and Non Line Of Sight (NLOS) are problematic. Hence, a radiating element such as a highly directive millimeter-wave antenna is needed, and beamforming is interested in. In beamforming, individual signals radiated from antennas are combined into a highly directional beam of electromagnetic (EM) radiation, thereby forming a highly directional electromagnetic radiation beam and maintaining a high gain.

[0003] In beamforming, the phases of signals input from different parts of a beamformer are adjusted, thereby radiating a highly directional well-defined beam in a specific direction. Here, the beamformer has a configuration in which elements (for example, antennas) that steer a radiation beam are arranged in an array. The phase of a radiation beam is adjusted by controlling the time delay of a signal adapted to each element of the array.

[0004] In recent years, beamforming using a metamaterial has received a great deal of attention because the metamaterial can steer an electromagnetic wave at a desired frequency by unique characteristics such as a refractive index, a permeability, and a dielectric constant. The metamaterial is an artificial medium. Its characteristics are acquired from embedded subwavelength structures arranged together like the arrangement of atoms in a normal material, and desired values of dielectric constant and permeability are exhibited within a measured frequency range, thereby steering an electromagnetic (EM) wave. The electromagnetic characteristics of the metamaterial are derived from the dimensions, geometry, direction, and arrangement of periodical structures of a circuit, and a material formed by those structures.

[0005] Gonghai Liu et al., "Ultrafast speed, large angle, and high resolution optical beam steering using widely tunable lasers”, OSA Continuum Vol. 2 (2019) p. 1746-1753.

[0006] As described above, beamforming that enables high directivity of a radiation beam at a millimeter-wave frequency is necessary for making an NLOS region small and reducing the influence of millimeter-wave attenuation. However, a beamforming technique including a metamaterial beamformer has the following problems.

[0007] First, one of the main characteristics of a beamforming device is a steering angle that the beamformer gives. This makes it possible to steer an electromagnetic wave in many directions using the same device and reduce the cost of the system and losses generated in the beamformer.

[0008] However, if the beam steering angle increases, a loss of the efficiency of the beamformer occurs due to phase mismatching. As a result, most part of a signal is lost due to scattering and radiation of a large number of side lobes during beamforming. This loss is related to the low efficiency of the device and reduces the strength of the radiated signal and the distance between the potential nodes in the system.

[0009] Also, a phase array used for beamforming in a high frequency has a complex structure, and the loss is large. In addition, the distance between radiating elements such as antennas is much larger than λ / 2 that is a distance essential for efficient beamforming. For that reason, metamaterial-based devices have been developed in place of the conventional phase arrays. However, the larger the steering angle is, the more difficult designing an efficient metamaterial-based beamformer is.

[0010] In order to solve the above-described problem, according to the present invention, there is provided an angle amplifier that a beamformed electromagnetic wave enters at a predetermined steering angle, comprising a plurality of metamaterial-based elements, wherein the metamaterial-based element is formed by a metamaterial cell and a filling material, the plurality of metamaterial-based elements are arranged point-symmetrical with respect to a center of the angle amplifier, and an exit angle of the electromagnetic wave that exits from the angle amplifier is larger than the predetermined steering angle.

[0011] According to the present invention, it is possible to amplify the steering angle of an incident electromagnetic wave beam that has undergone beamforming.

[0012] Fig. 1 is a schematic view showing the configurations of an angle amplifier and a beamforming device according to the first embodiment of the present invention;Fig. 2 shows a schematic front view and a schematic sectional view of the configuration of the angle amplifier according to the first embodiment of the present invention;Fig. 3 is a view for explaining the principle of the angle amplifier according to the first embodiment of the present invention;Fig. 4A is a view for explaining the principle of the angle amplifier according to the first embodiment of the present invention;Fig. 4B is a view for explaining the principle of the angle amplifier according to the first embodiment of the present invention;Fig. 5 is a view for explaining the principle of the angle amplifier according to the first embodiment of the present invention;Fig. 6A is a view showing an example of the configuration of a metamaterial cell in the angle amplifier according to the first embodiment of the present invention;Fig. 6B is a view showing an example of the configuration of a metamaterial cell in the angle amplifier according to the first embodiment of the present invention;Fig. 6C is a view showing an example of the configuration of a metamaterial cell in the angle amplifier according to the first embodiment of the present invention;Fig. 6D is a view showing an example of the configuration of a metamaterial cell in the angle amplifier according to the first embodiment of the present invention;Fig. 6E is a view showing an example of the configuration of a metamaterial cell in the angle amplifier according to the first embodiment of the present invention;Fig. 6F is a view showing an example of the configuration of a metamaterial cell in the angle amplifier according to the first embodiment of the present invention;Fig. 7 is a view for explaining an application example of a beamforming device according to the first embodiment of the present invention;Fig. 8A is a view showing the distribution of phases in the x direction of the angle amplifier according to the first example of the present invention;Fig. 8B is a view showing a phase level distribution map in the angle amplifier according to the first example of the present invention;Fig. 9 is a schematic view showing the configuration of an angle amplifier according to the second example of the present invention;Fig. 10 is a view for explaining the effect of the angle amplifier according to the second example of the present invention;Fig. 11A is a schematic view showing the configuration of an angle amplifier according to the third example of the present invention; andFig. 11B is a schematic view showing the configuration of the angle amplifier according to the third example of the present invention.

[0013] <First Embodiment> An angle amplifier and a beamforming device according to the first embodiment of the present invention will be described with reference to Figs. 1 to 7.

[0014] <Configurations of Angle Amplifier and Beamforming Device> As shown in Fig. 1, a beamforming device 10 according to this embodiment includes a beamformer 11 and an angle amplifier 12.

[0015] As the beamformer 11, for example, a metamaterial-based beamformer is used.

[0016] The angle amplifier 12 is arranged close to the beamformer 11. For example, the distance between the angle amplifier 12 and the beamformer 11 is about 10 mm to 100 mm.

[0017] As the angle amplifier 12, for example, a metamaterial-based angle amplifier is used.

[0018] Fig. 2 shows a schematic front view 2_1 and a schematic sectional view 2_2 of the configuration of the angle amplifier 12. The angle amplifier 12 includes a plurality of metamaterial-based elements 121_1 to 121_n. As an example, the plurality of metamaterial-based elements 121_1 to 121_n have an array structure in which a plurality of rings having different radii are concentrically arranged (to be described later).

[0019] The plurality of metamaterial-based elements may be arranged point-symmetrical with respect to the center of the angle amplifier.

[0020] The metamaterial-based elements 121_1 to 121_n are formed by metamaterial cells and a filling material, and have a subwavelength resonant structure.

[0021] As the material of the metamaterial cells, a material having a high electric conductivity may be used. For example, a metal, a conductive polymer, carbon nanotubes, graphene, ITO, or the like can be used. Alternatively, as the material of the metamaterial cells, a dielectric material having a dielectric constant different from the filling medium may be used.

[0022] As the filling medium, an insulating polymer (parylene, SU-8, polyimide, or the like) or a dielectric material (SiO2, ZnO, or the like) may be used.

[0023] <Operations of Angle Amplifier and Beamforming Device> The operations of the angle amplifier and the beamforming device according to this embodiment will be described with reference to Fig. 1.

[0024] An electromagnetic wave radiated from an antenna 1 enters the beamformer 11 vertically.

[0025] The propagation direction of the electromagnetic wave is changed while the electromagnetic wave is transmitted through the beamformer 11. As a result, the electromagnetic wave exits from the beamformer 11 in a direction having an angle θA1with respect to the vertically entering direction (incident direction). The exit angles (θA1and θA2) of the electromagnetic wave from the beamformer will also be referred to as the "steering angles" of the beamformer 11 hereinafter.

[0026] The electromagnetic wave enters the angle amplifier 12 at the angle θA1(a solid line arrow A1 in Fig. 1) and passes through the angle amplifier 12, so the propagation direction of the electromagnetic wave is further changed. As a result, the electromagnetic wave exits from the angle amplifier 12 at an angle θB1larger than the angle θA1(a solid line arrow B1 in Fig. 1).

[0027] Thus, the electromagnetic wave (beam) that has entered the angle amplifier 12 at the angle θA1further changes the propagation direction and exits from the angle amplifier 12 at the increased angle θB1.That is, the angle amplifier 12 amplifies the steering angle of the beamformed electromagnetic wave beam.

[0028] Similarly, the electromagnetic wave that has exited from the beamformer 11 at the angle (steering angle) θA2enters the angle amplifier 12 at the angle θA2(a solid line arrow A2 in Fig. 1). The angle amplifier 12 further changes the propagation direction of the electromagnetic wave. As a result, the electromagnetic wave exits from the angle amplifier 12 at an angle θB2larger than the angle θA2(a solid line arrow B2 in Fig. 1). That is, the angle amplifier 12 amplifies the steering angle of the beamformed electromagnetic wave beam.

[0029] As described above, according to the angle amplifier 12, the steering angle of a beamformed electromagnetic wave beam can be amplified. For example, an electromagnetic wave beam that has entered the angle amplifier 12 at 10° exits at 15°, and the steering angle can be amplified to 1.5 times.

[0030] Here, if the propagation direction of the electromagnetic wave is not changed by the beamformer 11, the electromagnetic wave exits from the beamformer 11 in a vertical direction (a steering angle θ = 0). When this electromagnetic wave enters the center of the angle amplifier 12 in the vertical direction, the electromagnetic wave exits from the center of the angle amplifier 12 in the vertical direction (a dotted line arrow in Fig. 1). As a result, the steering angle is not amplified.

[0031] Hence, in the angle amplifier 12 according to the present invention, the electromagnetic wave needs to enter the angle amplifier 12 at a predetermined angle (θ > 0). That is, it is necessary to change the direction (exit angle) (θ > 0) of the beam by the beamformer 11. The incident angle to the angle amplifier 12 is preferably larger than 0° and not more than 30°.

[0032] Alternatively, even in a case where the propagation direction of the electromagnetic wave is not changed by the beamformer 11, and the electromagnetic wave exits from the beamformer 11 in the vertical direction (θ = 0), if the electromagnetic wave enters a portion other than the center of the angle amplifier 12 in the vertical direction, the propagation direction of the electromagnetic wave changes, and the electromagnetic wave exits from the angle amplifier 12 at a predetermined angle. As a result, the steering angle is amplified.

[0033] <Principle of Angle Amplifier> The principle of the angle amplifier 12 according to this embodiment will be described with reference to Fig. 3.

[0034] The angle amplifier 12 is designed based on the design of a concave lens. First, the design of a concave lens will be described with reference to Fig. 3. Fig. 3 schematically shows a case where an electromagnetic wave (for example, a light beam) enters a concave lens vertically.

[0035] Assume a case where a plurality of electromagnetic waves parallelly enter in the vertical incident direction (solid line arrows 3_1 in Fig. 3). The electromagnetic waves pass through the lens, then change the propagation directions, and exit in the respective directions (solid line arrows 3_2 in Fig. 3). The intersection of extended lines (dotted lines in Fig. 3) of the electromagnetic waves indicates a virtual focal point F of the concave lens. The virtual focal point F depends on the radius of curvature and the thickness of the concave lens, and depends on the material of the concave lens, for example, the dielectric constant and the refractive index of the material. A focal distance f of the concave lens is calculated by equation (1).

[0036] [Math. 1]：

[0037] where f is the focal distance, n1and n2are the refractive indices of a peripheral medium and the lens, respectively, R1and R2are the radii of curvature of the lens on the input side and the output side, respectively. The refractive index of the peripheral medium changes the focus position. For example, in a case of air, based on n = 1, equation (1) is simplified, as indicated by equation (2).

[0038] [Math. 2]：

[0039] Equations (1) and (2) are equations applied to an optical system, and a refractive index n is used. On the other hand, in the millimeter-wave band, the dielectric constant is more important than the refractive index n. Hence, using the dielectric constant of the medium, the refractive index n can be replaced with n = √εμ. Assuming that the permeability equals 1, n1can be replaced using the dielectric constant ε0= 1 of air, and n2can be replaced using the dielectric constant of the lens material.

[0040] Hence, equation (2) can be expressed as equation (3).

[0041] [Math. 3]：

[0042] where, in the concave lens, the values of f, R1, and R2are negative values.

[0043] If only a millimeter-wave beam passing through the lens is assumed, the amplified angle (extended angle) can be derived by a Snell's expression.

[0044] [Math. 4]：

[0045] Here, θ1is the incident angle, and θ2is the exit angle. Also, n1is the refractive index of the peripheral medium, and n2is the refractive index of the lens material. As described above, the refractive index of the material can be replaced with the dielectric constant of the medium or a phase velocity ν1 / ν2in the two media. If application of the angle amplifier in the millimeter-wave band is taken into consideration, it is effective to design, using the dielectric constant or the phase velocity, a lens shape using a metamaterial.

[0046] In this way, the angle (extended angle) θ2at which the electromagnetic wave (millimeter wave) that has entered the angle amplifier at the angle θ1exits can be acquired by equation (4).

[0047] The angle amplifier 12 according to this embodiment will be described next based on the above-described concave lens. In the angle amplifier 12, the continuous surface of the concave lens is quantized to metamaterial cells having different dielectric constants. Fig. 4A shows, as an example, a schematic front view 4_1 and a schematic sectional view 4_2 of the angle amplifier (metamaterial cell angle amplifier) 12 using metamaterial-based elements with the metamaterial cells. Also, a schematic sectional view 4_3 of a normal concave lens is shown as an inserted drawing for the sake of comparison.

[0048] As shown in Fig. 4A, the continuous concave lens is quantized to a metamaterial lens including metamaterial cells with different dielectric constants.

[0049] As an example, the plurality of metamaterial-based elements are a plurality of rings having different radii and are arranged concentrically. The dielectric constant of the metamaterial-based element has a lowest value ε1at the center of the device, increases toward a lens end, and has a dielectric constant εnat the lens end. The dielectric constant changes ε1to εnare obtained by adjusting the characteristics of the metamaterial cells that form the metamaterial angle amplifier (for example, WO 2022 / 153388). Thus, the metamaterial angle amplifier 12 comprises a region in which values of dielectric constants of the plurality of metamaterial-based elements are set to increase from the center of the angle amplifier to an outside.

[0050] The metamaterial angle amplifier 12 may comprise the plurality of regions, in which values of dielectric constants of the plurality of metamaterial-based elements are set to increase from the center of the angle amplifier to an outside as shown in Fig. 4B. In the metamaterial angle amplifier 12, the dielectric constant changes ε1to εnare repeated. In Fig. 4B, an example of the regions of three has been shown. However, the present invention is not limited to these. The plurality of regions such as two, four, five or the like may be used. In the metamaterial angle amplifier 12, the dielectric constant may be periodically changed.

[0051] As shown in Fig. 5, the metamaterial angle amplifier 12 is a flat metamaterial concave lens. The distance (focal distance) f with respect to the virtual focal point F of the output wave of the metamaterial angle amplifier 12 is calculated by the same methodology as an optical concave lens. The thickness of the lens depends on the design of the metamaterial cells that form the device. The size of the metamaterial angle amplifier 12 depends on the distance between the beamformer 11 and the angle amplifier 12, the width of a radiation beam, and the like.

[0052] Figs. 6A to 6F show typical configuration examples of metamaterial cells (for example, WO 2023 / 073810). A region indicated by black in Figs. 6A to 6C represents a metamaterial cell. A region indicated by hatching in Figs. 6D to 6F represents a metamaterial cell.

[0053] In the configuration examples shown in Figs. 6A to 6C, a plurality of metamaterial cells are arranged in multiple stages. Here, a single metamaterial cell may be arranged.

[0054] At a predetermined frequency, the metamaterial cell couples with an electric component or a magnetic component of an incident electromagnetic wave and resonates. For resonance excitation, the size of the metamaterial is not more than the wavelength λ of the incident electromagnetic wave (millimeter wave), and is preferably not more than the λ / 2.

[0055] Metamaterial cells used for a gradient metamaterial concave lens in the angle amplifier 12 are designed based on metallic structures or dielectric materials of various dielectric constants.

[0056] In a case of design based on a metallic structure, a metamaterial cell is designed based on a condition that the body of the cell can couple with the external electric field portion of an EM wave. Here, the EM wave is generated by a radiating element and beamformed toward the angle amplifier 12. Also, the electric field E is used to introduce a current flow to the conductive structure of the metamaterial cell.

[0057] In a case of design based on a dielectric material cell, a metamaterial cell is designed based on the electric dipoles or magnetic dipoles in the material.

[0058] In the cases of design based on the metallic structure and the dielectric material cell, the size, the shape, the period of resonant cells, and other parameters are optimized to implement a desired millimeter-wave frequency range.

[0059] <Effect> Conventionally, when increasing the beam steering angle using only a beamformer, a loss of the efficiency of the beamformer is caused by phase mismatching.

[0060] According to the angle amplifier of this embodiment, since the beam steering angle need not be increased in the beamformer, it is possible to suppress the loss of the efficiency of the beamformer due to phase mismatching and amplify the beam steering angle.

[0061] <Application Example of Beamforming Device> Fig. 7 shows the use form of beamforming in a high-frequency range. The beamforming device 10 is placed in the radiating element (antenna) 1. For example, the beamforming device 10 includes a metamaterial-based beamformer, and the angle amplifier according to this embodiment.

[0062] In this application example, a direct LOS (line of sight) exists between the radiating element 1 and a user 7_1. On the other hand, a signal radiated from the antenna 1 to a user 7_2 is blocked by an obstacle 7_3. Hence, the signal is beamformed toward another device 7_4 such as a reflection type beamformer and reflected, via an additional system, to an NLOS region 7_5 where the user 7_2 exists.

[0063] According to the beamforming device of this embodiment, since the angle amplifier according to this embodiment is provided, the steering angle can largely be changed, and the degree of freedom for selecting a path to avoid an obstacle can be increased. Also, since the loss of the efficiency of the beamformer caused by phase mismatching is suppressed, a high-quality signal can be transmitted to the user 7_2.

[0064] <First Example> An angle amplifier and a beamforming device according to the first example of the present invention will be described with reference to Figs. 8A and 8B.

[0065] <Configuration of Angle Amplifier> An angle amplifier according to this example is a metamaterial angle amplifier and includes a single metamaterial concave lens. By the metamaterial concave lens, the incident angle of a beamformed input wave can be extended, as described above.

[0066] The metamaterial concave lens of this angle amplifier is designed as follows.

[0067] For an operating wavelength λ, letting x and y be the dimensions of the lens, and a be the dimension (the length of one side) of a metamaterial cell having a square shape, a phaseΨ necessary for the design of the concave lens is given by

[0068] [Math. 5]：

[0069] where, f1z, f1y, and f1xare the coordinates of the incident point of the input wave, f2z, f2y, and f2xare the coordinates of the focal point of the output wave, and x and y are the coordinates along the x- and y-axes on the concave lens.

[0070] Fig. 8A shows a continuous phase distribution in the x direction of the concave lens in the metamaterial angle amplifier in the 300-GHz frequency band. The concave lens is configured in which the dielectric constant changes ε1to εnare repeated similarly to the lens as shown in Fig. 4B. The concave lens is designed based on the Fresnel zone theory in multi-bits. To implement the phase distribution, it is necessary to obtain a desired phase delay by designing a metamaterial cell having an appropriate dielectric constant. The continuous phase distribution of the concave lens is calculated by equation (5), and quantized to a finite phase level number.

[0071] In this example, 8 levels are used in steps of π / 4. For example, a phaseΨ1of first level is 0 - π / 4, a phaseΨ2of second level is π / 4 - π / 2, a phaseΨ3of third level is π / 2 - 3π / 4, a phaseΨ4of fourth level is 3π / 4 - π, a phaseΨ5of fifth level is π - 5π / 4, a phaseΨ6of sixth level is 5π / 4 - 3π / 2, a phaseΨ7of seventh level is 3π / 2 - 7π / 4, and a phaseΨ8of eighth level is 7π / 4 - 2π.

[0072] In the metamaterial angle amplifier, to each phase level, a metamaterial cell having a phase value according to the phase level is assigned. Here, the phase value is adjusted by the shape of the metamaterial cell or the like (for example, WO 2023 / 073810).

[0073] Fig. 8B shows the calculation result of a phase level distribution map (xy plane). In the figure, the black part shows that the value of phase is small. The black part shows that the value of phase is large. A change of the color from white to black shows that the value of phase increases. In the phase level distribution map, x = 100 mm, y = 100 mm, and a = 0.2 mm were calculated, by equation (5), in the 8 Fresnel zones (8 levels). Different phase values of 8 levels were assigned to each zone within the range of 2π.

[0074] As shown in Fig. 8B, in the metamaterial angle amplifier, the phase levels are large in the center of the amplifier and distributed like rings of a plurality of concentric circles with different radii. In the distribution, the phase change fromΨ1toΨ8is repeated. Hence, in each ring-shaped zone, the phase of an incident electromagnetic wave is shifted by a metamaterial cell having a different dielectric constant.

[0075] As described above, the angle amplifier according to this example is configured by setting n = 8 in the metamaterial concave lens shown in Fig. 4B. Here, the dielectric constants ε1to ε8correspond to the phasesΨ1toΨ8, respectively.

[0076] Also, the metamaterial-based element operates as a phase-shifting element. The metamaterial cell receives an electromagnetic wave signal having an arbitrary frequency and phase, and generates an output signal having the same frequency and a shifted phase. Here, the phase of the output signal is decided by the shape of the metamaterial cell.

[0077] According to the angle amplifier of this example, the phase of a beamformed incident electromagnetic wave beam can be shifted. By this phase shift, the exit angle of the electromagnetic wave beam can be made larger than the incident angle. That is, the steering angle of the electromagnetic wave beam can be amplified.

[0078] Also, according to the angle amplifier of this example, a flat concave lens of metamaterial can be formed.

[0079] <Second Example> An angle amplifier and a beamforming device according to the second example of the present invention will be described with reference to Figs. 9 and 10.

[0080] <Configuration of Angle Amplifier> An angle amplifier 22 according to this example is a metamaterial angle amplifier and includes a collimating lens or focus lens (first lens) 221, and a metamaterial concave lens 222, as shown in Fig. 9.

[0081] <Effect> Fig. 10 shows a metamaterial angle amplifier based on a single concave lens. If the distance between a beamformer and the metamaterial angle amplifier is relatively long, a propagating incident wave spreads radially, as shown in Fig. 10. Due to an increase of the spread of the beam, the directivity and power of the beam decrease.

[0082] In the angle amplifier 22 according to this example, as shown in Fig. 9, the radially spreading beam passes through the metamaterial collimating lens or metamaterial focus lens (first lens) 221, and the width of the beam decreases. The first lens 221 is designed to focus on the metamaterial concave lens for optimum performance. The collimated beam or focused beam is transmitted through the metamaterial concave lens 222 with the minimized beam spread.

[0083] According to the angle amplifier of this example, the spread of a beam whose steering angle is amplified can be reduced. It is also possible to reduce signal losses and improve the directivity and power of a millimeter-wave beam.

[0084] <Third Example> An angle amplifier and a beamforming device according to the third example of the present invention will be described with reference to Fig. 11A and 11B.

[0085] <Configuration of Angle Amplifier> An angle amplifier 32 according to this example is a metamaterial angle amplifier and includes an active collimating lens or active focus lens 321 and a metamaterial concave lens 322, as shown in Figs. 11A and 11B.

[0086] <Effect> As described above, the output beam from the beamformer spreads radially. If the beam is not controlled, and spread occurs, the total gain and transmission power decrease.

[0087] As shown in Figs. 11A and 11B, the metamaterial angle amplifier 32 includes the collimating / focus metamaterial lens (second lens) 321 that can actively be controlled, and the passive concave lens 322 for amplifying the angle.

[0088] The actively controllable lens (second lens) 321 is adjusted to change the capability of focusing, and the capability of focusing depends on the operation conditions of the metamaterial angle amplifier. By the second lens 321, the width of a beam that enters the concave lens 322 is changed. For example, as shown in Fig. 11A, if a beam strongly focuses on the concave lens 322, the output of the metamaterial angle amplifier 32 is a narrow beam with high power. Also, as shown in Fig. 11B, if a beam is broad on the concave lens 322, the output of the metamaterial angle amplifier 32 is a spread beam with low power.

[0089] According to the angle amplifier of this example, the width of an output beam that has undergone desired beamforming can accurately be controlled. For example, the transmission power of a signal between nodes of the system can be increased by a more focused beam. Also, a broader beam is used to improve area coverage in wireless communication.

[0090] In the embodiment of the present invention, examples of the circular concave lens have been described. However, the present invention is not limited to these. The shape of the metamaterial concave lens may be square, rectangular shape, polygonal shape, ellipse, or the like.

[0091] In the embodiment of the present invention, the term “ring” includes a circular geometry.

[0092] In the embodiment of the present invention, in the configurations of an angle amplifier and a beamforming device, examples of the structure, dimension, material, and the like of each constituent part have been described. However, the present invention is not limited to these. It is only necessary that the functions and effects of the angle amplifier and the beamforming device can be obtained.

[0093] Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications and combinations can be made by those who have normal knowledge in the field without departing from the technical scope of the present invention.

[0094] Some or all of the above-described exemplary embodiments can also be described as in the following supplementary notes but are not limited to the followings.

[0095] (Supplementary Note 1) There is provided an angle amplifier that a beamformed electromagnetic wave enters at a predetermined steering angle, comprising a plurality of metamaterial-based elements, wherein the metamaterial-based element is formed by a metamaterial cell and a filling material, the plurality of metamaterial-based elements are arranged point-symmetrical with respect to a center of the angle amplifier, and an exit angle of the electromagnetic wave that exits from the angle amplifier is larger than the predetermined steering angle.

[0096] (Supplementary Note 2) The angle amplifier according to Supplementary Note 1 comprises at least one region in which values of dielectric constants of the plurality of metamaterial-based elements are set to increase from the center of the angle amplifier to an outside.

[0097] (Supplementary Note 3) The angle amplifier according to Supplementary Note 2 comprises the plurality of regions.

[0098] (Supplementary Note 4) In the angle amplifier according to Supplementary Note 1 or 2, a value of a dielectric constant of the metamaterial-based element is set by quantizing a dielectric constant that continuously changes in a concave lens.

[0099] (Supplementary Note 5) In the angle amplifier according to any one of Supplementary Notes 1 to 3, the plurality of metamaterial-based elements are a plurality of rings having different radii and are arranged concentrically.

[0100] (Supplementary Note 6) The angle amplifier according to any one of Supplementary Notes 1 to 5 further comprises a first lens, wherein the first lens is one of a collimating lens and a focus lens, and a beam of the beamformed electromagnetic wave enters the first lens, and the beam of the electromagnetic wave whose width is reduced by the first lens enters.

[0101] (Supplementary Note 7) The angle amplifier according to any one of Supplementary Notes 1 to 6 further comprises a second lens, wherein the second lens is one of an active collimating lens and an active focus lens, and a beam of the beamformed electromagnetic wave enters the second lens, and the beam of the electromagnetic wave whose width is controlled by the second lens enters.

[0102] (Supplementary Note 8) There is provided a beamforming device comprising a beamformer that outputs a beamformed electromagnetic wave, and an angle amplifier according to any one of Supplementary Notes 1 to 7.

[0103] (Supplementary Note 9) In the angle amplifier according to any one of Supplementary Notes 1 to 7, the metamaterial-based element has a subwavelength resonant structure, and couples with an electric component or a magnetic component of the beamformed electromagnetic wave.

[0104] (Supplementary Note 10) In the angle amplifier according to any one of Supplementary Notes 1 to 7 and Supplementary Note 9, the steering angle is larger than 0° to not more than 30°.

[0105] (Supplementary Note 11) In the angle amplifier according to any one of Supplementary Notes 1 to 7 and Supplementary Notes 9 and 10, the metamaterial cell is made of a material having a high electric conductivity.

[0106] (Supplementary Note 12) In the angle amplifier according to any one of Supplementary Notes 1 to 7 and Supplementary Notes 9 to 11, the metamaterial cell is made of a dielectric material having a dielectric constant different from a filling medium.

[0107] (Supplementary Note 13) In the angle amplifier according to any one of Supplementary Notes 1 to 7 and Supplementary Notes 9 to 12, the filling material is made of an insulating polymer.

[0108] (Supplementary Note 14) In the angle amplifier according to any one of Supplementary Notes 1 to 7 and Supplementary Notes 9 to 13, the filling material is made of a dielectric material.

[0109] (Supplementary Note 15) In the angle amplifier according to any one of Supplementary Notes 1 to 7 and Supplementary Notes 9 to 14, the metamaterial cell receives an electromagnetic wave having an arbitrary frequency and phase, and generates an electromagnetic wave having the same frequency as the frequency and a changed phase.

[0110] The present invention is related to a beamforming technique and device, and can be applied to a millimeter-wave antenna or the like in high-frequency wireless communication.

[0111] 12...angle amplifier 121_1 to 121_n...metamaterial-based element

Claims

1. An angle amplifier that a beamformed electromagnetic wave enters at a predetermined steering angle, comprising: 　　　　a plurality of metamaterial-based elements, 　　　　wherein the metamaterial-based element is formed by a metamaterial cell and a filling material, 　　　　the plurality of metamaterial-based elements are arranged point-symmetrical with respect to a center of the angle amplifier, and 　　　　an exit angle of the electromagnetic wave that exits from the angle amplifier is larger than the predetermined steering angle.

2. The angle amplifier according to claim 1, comprising at least one region in which values of dielectric constants of the plurality of metamaterial-based elements are set to increase from the center of the angle amplifier to an outside.

3. The angle amplifier according to claim 2, comprising the plurality of regions.

4. The angle amplifier according to claim 1, wherein a value of a dielectric constant of the metamaterial-based element is set by quantizing a dielectric constant that continuously changes in a concave lens.

5. The angle amplifier according to claim 1, wherein the plurality of metamaterial-based elements are a plurality of rings having different radii and are arranged concentrically.

6. The angle amplifier according to claim 1, further comprising a first lens, 　　　　wherein the first lens is one of a collimating lens and a focus lens, and 　　　　a beam of the beamformed electromagnetic wave enters the first lens, and the beam of the electromagnetic wave whose width is reduced by the first lens enters.

7. The angle amplifier according to claim 1, further comprising a second lens, 　　　　wherein the second lens is one of an active collimating lens and an active focus lens, and 　　　　a beam of the beamformed electromagnetic wave enters the second lens, and the beam of the electromagnetic wave whose width is controlled by the second lens enters.

8. A beamforming device comprising: 　　　　a beamformer that outputs a beamformed electromagnetic wave; and 　　　　an angle amplifier according to claim 1.

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