Electromagnetic wave direction change structure and method for manufacturing electromagnetic wave direction change structure

Abstract

Provided is an electromagnetic wave direction change structure in which a plurality of unit elements (10, 11) each having a substrate (100) and conductor patterns (101, 102) formed on a first main surface of the substrate (100) are arranged side by side in at least one dimension. One or more first unit elements (11) among the plurality of unit elements (10, 11) are provided with a substrate (100), a conductor pattern (102), and a conductor part (104) having a processed part obtained by processing a part of the conductor pattern (102). The processed part has at least one of a cut part (103) obtained by cutting a part of the conductor pattern (102), and a connection part for connecting conductor pattern parts formed separately from each other of the conductor pattern (102).

Description

Electromagnetic wave redirection structure and method for manufacturing the electromagnetic wave redirection structure

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to electromagnetic wave redirecting structures and methods of manufacturing electromagnetic wave redirecting structures.

[0002] In recent years, in order to achieve high speed and large capacity wireless access, utilization of high frequency bands above 100 GHz, such as millimeter waves and sub-terahertz waves, which can ensure wide bandwidth, has been considered.

[0003] On the other hand, in the aforementioned high frequency bands, electromagnetic waves (radio waves) tend to travel in a straighter direction and are less likely to diffract compared to microwaves, which can lead to blind areas due to obstacles such as buildings and roadside trees. Therefore, in order to eliminate blind areas (e.g., to improve communication areas and communication quality), the introduction of metasurfaces that can reflect and / or transmit electromagnetic waves in any direction has been considered (see, for example, Non-Patent Documents 1 to 3).

[0004] "A Dual-Polarized Reconfigurable Reflectarray Antenna Based on Dual-Channel Programmable Metasurface", IEEE Transactions on Antennas and Propagation, vol. 70, no. 9, pp.7403-7412, 2022 "Beam Steering Property of Perfect Anomalous Metareflectors Using Stretchable Elastic Substrates for 6G Applications", 2023 Asia-Pacific Microwave Conference (APMC), Taipei, Taiwan, pp.884-8862023, 2023"mm-Wave Metasurface Unit Cells Achieving Millisecond Response Through Polymer Network Liquid Crystals", IEEE Access, vol. 10, pp.127928-127938, 2022

[0005] However, the required characteristics (reflection characteristics or transmission characteristics) of electromagnetic wave redirecting structures such as metasurface substrates may vary depending on the installation and operation location. To accommodate various characteristics, it is possible to manufacture passive metasurface substrates for each required characteristic, but this has the problem of increasing the number of product varieties. The reflection characteristics include the reflection direction, and the transmission characteristics include the transmission direction.

[0006] Therefore, the present disclosure provides an electromagnetic wave direction-changing structure that can achieve desired characteristics while suppressing an increase in the number of product varieties, and a method for manufacturing the electromagnetic wave direction-changing structure.

[0007] An electromagnetic wave direction-changing structure according to one aspect of the present disclosure is an electromagnetic wave direction-changing structure in which a plurality of unit elements, each having a substrate and a conductor pattern formed on a first main surface of the substrate, are arranged side by side in at least one dimension, and one or more first unit elements among the plurality of unit elements include the substrate, the conductor pattern, and a conductor portion having a processed portion obtained by processing a portion of the conductor pattern, and the processed portion has at least one of a cut portion obtained by cutting a portion of the conductor pattern and a connection portion that connects conductor pattern portions formed at a distance from each other in the conductor pattern.

[0008] A manufacturing method of an electromagnetic wave direction-changing structure according to one aspect of the present disclosure is a manufacturing method of an electromagnetic wave direction-changing structure in which a plurality of unit elements, each having a substrate and a conductor pattern formed on a main surface of the substrate, are arranged in a line at least one-dimensionally, the method comprising the steps of: preparing a structure in which a plurality of the unit elements, each having the conductor pattern formed thereon, are arranged in a line; and processing the conductor pattern in accordance with desired reflection characteristics or transmission characteristics for target electromagnetic waves, the processing including at least one of cutting a portion of the conductor pattern for at least one of the plurality of unit elements; and joining conductor pattern portions of the conductor pattern that are formed at a distance from each other.

[0009] According to one aspect of the present disclosure, it is possible to realize an electromagnetic wave direction-changing structure or the like that can achieve desired characteristics while suppressing an increase in the variety of products.

[0010] FIG. 1 is a diagram showing an example of installation of a metasurface reflector. FIG. 2 is a top view showing a metasurface reflector according to the first embodiment. FIG. 3A is a top view showing a second unit element according to the first embodiment. FIG. 3B is a perspective view showing the second unit element according to the first embodiment. FIG. 3C is a side view showing the second unit element according to the first embodiment. FIG. 4A is a top view showing a first unit element according to the first embodiment. FIG. 4B is a perspective view showing the first unit element according to the first embodiment. FIG. 4C is a side view showing the first unit element according to the first embodiment. FIG. 5 is a flowchart showing a manufacturing method of a metasurface reflector according to the first embodiment. FIG. 6 is a top view showing a passive metasurface reflector according to the first embodiment. FIG. 7A is a diagram showing frequency responses of amplitude in unit elements before and after processing according to the first embodiment. FIG. 7B is a diagram showing frequency responses of phase characteristics in unit elements before and after processing according to the first embodiment. FIG. 8 is a diagram showing electromagnetic field simulation results of a bistatic RCS in the metasurface reflector according to the first embodiment. FIG. 9A is a top view showing a first example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9B is a top view showing a second example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9C is a top view showing a third example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9D is a top view showing a fourth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9E is a top view showing a fifth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9F is a top view showing a sixth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9G is a top view showing a seventh example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9H is a top view showing an eighth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9I is a top view showing a ninth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. Fig. 9J is a top view showing a tenth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. Fig. 9K is a top view showing an eleventh example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. Fig. 9L is a top view showing a twelfth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1.FIG. 9M is a top view showing a thirteenth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9N is a top view showing a fourteenth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9O is a top view showing a fifteenth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 9P is a top view showing a sixteenth example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 10A is a top view showing another first example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 10B is a top view showing another second example of a conductor portion of a first unit element according to Modification 1 of Embodiment 1. FIG. 11A is a bottom view showing a first example of a back surface pattern of a first unit element according to Modification 1 of Embodiment 1. FIG. 11B is a bottom view showing a second example of a back surface pattern of a first unit element according to Modification 1 of Embodiment 1. FIG. 12A is a top view showing a first example of a conductor portion of a first unit element according to Modification 2 of Embodiment 1. FIG. 12B is a top view showing a second example of a conductor portion of a first unit element according to Modification 2 of Embodiment 1. FIG. 12C is a top view showing a third example of a conductor portion of a first unit element according to Modification 2 of Embodiment 1. FIG. 12D is a top view showing a fourth example of a conductor portion of a first unit element according to Modification 2 of Embodiment 1. FIG. 12E is a top view showing a fifth example of a conductor portion of a first unit element according to Modification 2 of Embodiment 1. FIG. 13A is a top view showing a conductor portion of a second unit element according to Modification 3 of Embodiment 1. FIG. 13B is a top view showing a first example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. FIG. 13C is a top view showing a second example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. FIG. 13D is a top view showing a third example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. FIG. 13E is a top view showing a fourth example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. Fig. 13F is a top view showing a fifth example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. Fig. 13G is a top view showing a sixth example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. Fig. 13H is a top view showing a seventh example of a conductor portion of a first unit element according to Modification 3 of Embodiment 1. Fig. 14A is a top view showing a second unit element according to Embodiment 2. Fig. 14B is a perspective view showing a second unit element according to Embodiment 2.Fig. 14C is a side view showing a second unit element according to embodiment 2. Fig. 15A is a top view showing a first unit element according to embodiment 2. Fig. 15B is a perspective view showing the first unit element according to embodiment 2. Fig. 15C is a side view showing the first unit element according to embodiment 2.

[0011] (Background to the Invention of the Present Disclosure) Before describing the embodiments of the present disclosure, the background to the invention of the present disclosure will be described with reference to FIG. 1. FIG. 1 is a diagram showing an example of the installation of a metasurface reflector. Note that the electromagnetic wave redirection structure is not limited to a metasurface reflector, but may also be a metasurface transmission plate. Hereinafter, the metasurface reflector and metasurface transmission plate will also be referred to as metasurfaces or metasurface substrates.

[0012] As shown in Fig. 1, for example, when electromagnetic waves in a high frequency band above 100 GHz are transmitted from a base station (BS) installed on the roof of a building, the electromagnetic waves tend to travel in a straight line and are difficult to diffract, so that blind areas (hatched areas shown in Fig. 1) to the electromagnetic waves are generated by obstacles such as buildings and roadside trees. In the case of Fig. 1, blind areas are generated between buildings, and it is difficult for the electromagnetic waves from the base station to reach mobile stations (MS) such as smartphones carried by people in the blind areas.

[0013] Therefore, metasurface reflectors are used to reflect (or transmit) electromagnetic waves from base stations in desired directions. Metasurface reflectors are used by fixing them to structures such as buildings.

[0014] Such a metasurface substrate is constructed by arranging a large number of small elements (unit elements) that are less than half the wavelength of the target electromagnetic wave in a planar manner (for example, by arranging the unit elements in an array), and each element changes the phase and amplitude of the incident electromagnetic field, thereby making it possible to change the phase and amplitude distribution of the incident electromagnetic field. Note that unit elements are also called radiating elements, structures, antenna elements, capacitive elements, reflecting elements, etc.

[0015] Active metasurface substrates, which can dynamically change the direction of reflection and / or transmission of electromagnetic waves, enable dynamic control of the reflection phase and / or transmission phase by electronically controlling switching devices such as PIN diodes and varactor diodes implemented in each unit element using a power supply or control system.

[0016] Terms that refer to technologies similar to active metasurfaces include RIS (Reconfigurable Intelligent Surface), LIS (Large Intelligent Surface), IRS (Intelligent Reflecting Surface) that focuses only on controlling reflected waves, and RRA (Reconfigurable Reflect Array).

[0017] For example, Non-Patent Document 1 discloses a beam scanning antenna compatible with both horizontal and vertical polarizations, in which a reconfigurable reflect array (RRA) uses a PIN diode as a switching device to electronically control the phases of horizontal and vertical polarizations independently.

[0018] Furthermore, for example, Non-Patent Document 2 discloses a reconfigurable intelligent surface (RIS) using liquid crystals (LC) for electromagnetic waves with frequencies in the sub-terahertz range above 100 GHz. In Non-Patent Document 2, high-frequency beam scanning is achieved by electronically controlling the orientation of the liquid crystal with an electric field.

[0019] Furthermore, for example, Non-Patent Document 3 discloses that in order to reduce loss for frequencies above 100 GHz, a stretchable material is used as a substrate, and the substrate is mechanically stretched to physically change the dimensions, thereby realizing beam scanning in the high frequency band.

[0020] However, in the technology of Non-Patent Document 1, the frequencies to which the switching device can be applied are limited to microwaves and millimeter waves up to about 100 GHz, and application to sub-terahertz waves above 100 GHz is difficult. Furthermore, the technology of Non-Patent Document 2 has a problem of reducing the loss of the liquid crystal material. Furthermore, the technology of Non-Patent Document 3 has problems such as degradation over long periods of use and under harsh environmental conditions.

[0021] As described above, active metasurfaces such as those shown in Non-Patent Documents 1 to 3 have issues. Therefore, it is expected that passive metasurfaces will become more widespread in the future. Passive metasurfaces are easy to manufacture, durable, and low-cost. Furthermore, passive metasurfaces do not require a power supply or control system, making installation and maintenance easy. In passive metasurfaces, the phase (impedance) of the reflected or transmitted wave is adjusted by adjusting the dimensions of the conductor pattern for each unit element at the time of manufacturing the metasurface substrate.

[0022] However, in the case of passive metasurfaces, the antenna pattern is determined at the design stage, so once manufactured, the reflection and / or transmission direction of the electromagnetic waves cannot be switched or controlled (they are fixed). In other words, with passive metasurfaces, it is difficult to adjust the phase according to the installation and operation location. Therefore, passive metasurfaces require a customized design for a specific installation and operation location or application, which poses the problem of increasing the number of manufacturing molds and inventory types and variations.

[0023] Therefore, the inventors of the present application have conducted extensive research into electromagnetic wave direction-changing structures and the like that can achieve desired characteristics (for example, be capable of performing phase control according to the installation location, etc.) while suppressing an increase in the number of product varieties when using passive metasurfaces, and have devised the electromagnetic wave direction-changing structures and the like shown below.

[0024] Further advantages and effects of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or effects may be provided by some embodiments and features described in the specification and drawings, but not all of them necessarily need to be provided to obtain one or more identical features.

[0025] An electromagnetic wave direction-changing structure according to a first aspect of the present disclosure is an electromagnetic wave direction-changing structure in which a plurality of unit elements, each having a substrate and a conductor pattern formed on a first main surface of the substrate, are arranged side by side in at least one dimension, and one or more first unit elements among the plurality of unit elements include the substrate, the conductor pattern, and a conductor portion having a processed portion obtained by processing a portion of the conductor pattern, and the processed portion has at least one of a cut portion obtained by cutting a portion of the conductor pattern, and a connection portion that connects conductor pattern portions formed at a distance from each other in the conductor pattern.

[0026] This allows the reflection characteristics of the electromagnetic wave redirection structure to be adjusted according to the installation location, etc., using the processing unit. In other words, there is no need to customize the design to suit a specific installation / operation location or application, and an increase in the variety and variations of manufacturing molds or inventory can be suppressed. Furthermore, the processing unit allows the area (or element length) of the conductor pattern to be changed to obtain the desired reflection characteristics. Therefore, the electromagnetic wave redirection structure can achieve the desired characteristics while suppressing an increase in the number of product varieties. For example, it is possible to achieve an electromagnetic wave redirection structure that can handle high frequencies above 100 GHz while suppressing an increase in the number of design patterns and product varieties.

[0027] Also, for example, the electromagnetic wave direction-changing structure according to the second aspect may be the electromagnetic wave direction-changing structure according to the first aspect, wherein the processed portion has at least the cut portion, and the cut portion may be a portion formed by any one of laser cutting, punching, and wire cutting.

[0028] This allows the conductor pattern to be changed by cutting so as to obtain desired reflection characteristics.

[0029] Also, for example, the electromagnetic wave direction-changing structure according to the third aspect may be the electromagnetic wave direction-changing structure according to the first aspect, wherein the processed portion has at least the connection portion, and the connection portion may include at least one of silver paste, solder, an inductance element, a capacitance element, a conductive adhesive, a conductive polymer, and wire bonding.

[0030] This allows the conductor pattern to be changed by mounting components so as to obtain desired reflection characteristics.

[0031] Furthermore, for example, an electromagnetic wave direction-changing structure according to a fourth aspect may be an electromagnetic wave direction-changing structure according to any one of the first to third aspects, and the one or more first unit elements may be unit elements determined from among a plurality of the unit elements according to a phase distribution quantized by at least one bit so as to reflect or transmit an electromagnetic wave in a desired direction when the plurality of unit elements are arrayed.

[0032] In this way, since a phase distribution quantized by at least one bit is used, it is possible to determine a unit element to be processed that will obtain desired reflection characteristics.

[0033] Furthermore, for example, an electromagnetic wave direction-changing structure according to a fifth aspect may be an electromagnetic wave direction-changing structure according to any one of the first to fourth aspects, wherein the plurality of unit elements have one or more second unit elements, and the one or more first unit elements and the one or more second unit elements have the conductor pattern extending radially from a predetermined position as a center in a top view, and the one or more first unit elements have the processed portion at the predetermined position.

[0034] This allows the area of ​​the conductor pattern (or element length) to be changed effectively, thereby reducing the number of processing steps and processing locations.

[0035] Furthermore, for example, an electromagnetic wave direction-changing structure according to a sixth aspect may be an electromagnetic wave direction-changing structure according to any one of the first to fifth aspects, wherein the one or more first unit elements have the conductor portion that is line-symmetric and point-symmetric with a predetermined position as a central axis when viewed from above, and the plurality of unit elements may have one or more second unit elements that have the conductor pattern that is line-symmetric and point-symmetric with the predetermined position as a central axis when viewed from above.

[0036] As a result, the unit elements have conductor patterns that are both line-symmetric and point-symmetric, making it possible to realize an electromagnetic wave direction changing structure that is compatible with both horizontally and vertically polarized waves.

[0037] Furthermore, for example, an electromagnetic wave direction-changing structure according to a seventh aspect is an electromagnetic wave direction-changing structure according to any one of the first to sixth aspects, wherein the plurality of unit elements have one or more second unit elements in addition to the one or more first unit elements, and the conductor pattern of the one or more first unit elements and the conductor pattern of the one or more second unit elements may have different shapes.

[0038] As a result, the first unit element and the second unit element have different element shapes (conductor pattern shapes), which makes it possible to achieve a wider bandwidth for the electromagnetic wave direction changing structure compared to when it has only one type of element shape.

[0039] Furthermore, for example, the electromagnetic wave direction-changing structure according to the eighth aspect may be an electromagnetic wave direction-changing structure according to any one of the first to seventh aspects, and the conductor patterns of the plurality of unit elements may have at least two types of element shape portions.

[0040] As a result, the unit element has at least two types of element shaped portions within the unit element, and therefore it is possible to realize a broader bandwidth for the electromagnetic wave direction changing structure compared to when the unit element has only one type of element shaped portion.

[0041] Furthermore, for example, an electromagnetic wave direction-changing structure according to a ninth aspect may be the electromagnetic wave direction-changing structure according to the eighth aspect, wherein the at least two types of element-shaped portions include a loop-shaped portion having a loop shape, and a radiating portion arranged inside the loop-shaped portion and having a radial shape.

[0042] As a result, the unit element has a loop+cross structure, and by reducing the change in cross length, it is possible to reduce the influence of processing errors in subsequent processes.

[0043] Furthermore, for example, an electromagnetic wave direction-changing structure according to a tenth aspect is an electromagnetic wave direction-changing structure according to any one of the first to ninth aspects, wherein the plurality of unit elements have one or more second unit elements in addition to the one or more first unit elements, and the one or more first unit elements and the one or more second unit elements may have different phase characteristics with respect to the target electromagnetic wave.

[0044] As a result, the phase characteristic among the frequency characteristics is changed by the processing, so that the phase characteristic can be obtained as the desired characteristic.

[0045] Furthermore, for example, an electromagnetic wave direction-changing structure according to an eleventh aspect may be an electromagnetic wave direction-changing structure according to the tenth aspect, wherein the one or more first unit elements have n phases (n: natural number) in a target electromagnetic wave, and the n phases of the one or more first unit elements may differ from the phases of the electromagnetic wave in the one or more second unit elements by 180 / (0.5 + 0.5n) degrees.

[0046] This makes it possible to suppress quantization lobes that appear at angles symmetrical to the desired direction when phase quantization is multi-valued.

[0047] Furthermore, for example, the electromagnetic wave direction-changing structure according to the twelfth aspect may be an electromagnetic wave direction-changing structure according to any one of the first to eleventh aspects, and may have a GND layer on a second main surface of the substrate opposite to the first main surface.

[0048] This makes it possible to realize a metasurface reflector that can achieve the desired characteristics while suppressing an increase in the number of product varieties.

[0049] Furthermore, for example, an electromagnetic wave direction-changing structure according to a thirteenth aspect may be an electromagnetic wave direction-changing structure according to any one of the first to twelfth aspects, and the plurality of unit elements may have an element length of 0.05 wavelengths or more and 0.5 wavelengths or less of the wavelength of the target electromagnetic wave.

[0050] This makes it possible to suppress the occurrence of unwanted radiation (grating lobes) in directions other than the desired direction.

[0051] A manufacturing method of an electromagnetic wave direction-changing structure according to a fourteenth aspect of the present disclosure is a manufacturing method of an electromagnetic wave direction-changing structure in which a plurality of unit elements, each having a substrate and a conductor pattern formed on a main surface of the substrate, are arranged in a line at least one-dimensionally, the method comprising the steps of: preparing a structure in which a plurality of the unit elements, each having the conductor pattern formed thereon, are arranged in a line; and processing the conductor pattern in accordance with desired reflection characteristics or transmission characteristics for target electromagnetic waves, the processing including at least one of cutting a portion of the conductor pattern for at least one of the plurality of unit elements; and joining conductor pattern portions of the conductor pattern that are formed at a distance from each other.

[0052] This provides the same effect as the electromagnetic wave direction changing structure described above.

[0053] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed descriptions than necessary may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Furthermore, the numerical values, shapes, components, component placement and connection forms, steps (processes), and order of steps (processes) shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0054] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims. Furthermore, each drawing is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the drawings do not necessarily match. Furthermore, in each drawing, substantially identical components are designated by the same reference numerals, and duplicate descriptions may be omitted or simplified.

[0055] In addition, in this specification and drawings, the X, Y, and Z axes represent the three axes of a right-handed three-dimensional Cartesian coordinate system. In the embodiment, the Z axis direction is the stacking direction (thickness direction) of the metasurface substrate. In addition, in this specification, "top view" means viewing the metasurface substrate along the stacking direction of the metasurface substrate.

[0056] Furthermore, in this specification, terms indicating the relationship between elements, such as "same," terms indicating the shape of elements, such as "rectangle" and "circle," as well as numerical values ​​and numerical ranges, are not expressions that express only the strict meaning, but are expressions that also include a substantially equivalent range, for example, a difference of about several percent (or about 10%).

[0057] Furthermore, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components unless otherwise specified, but are used for the purpose of avoiding confusion and distinguishing between components of the same type.

[0058] (Embodiment 1) Hereinafter, an electromagnetic wave redirecting structure according to this embodiment will be described with reference to Figures 2 to 8. In the following embodiments, a metasurface reflector will be mainly used for the description, but the electromagnetic wave redirecting structure may also be a metasurface transmission plate or the like. In the case of a metasurface transmission plate, reflection in the following description will be read as transmission.

[0059] [1-1. Configuration of Metasurface Reflector] First, the configuration of the metasurface reflector according to this embodiment will be described with reference to Fig. 2 to Fig. 4C. Fig. 2 is a top view showing the metasurface reflector 1 according to this embodiment.

[0060] 2, the metasurface reflector 1 is configured by arranging a plurality of unit elements 10 and 11 in an array (e.g., two-dimensionally). In this embodiment, the metasurface reflector 1 has a configuration in which rows of a plurality of unit elements 10 arranged in the X-axis direction and rows of a plurality of unit elements 11 arranged in the X-axis direction are alternately arranged in the Y-axis direction. The metasurface reflector 1 also has a metasurface structure.

[0061] The unit elements 10 and 11 are each a region (regions separated by dashed lines in FIG. 2 ) that divides the substrate 100 into multiple regions when viewed from above, and reflect (or transmit in the case of a metasurface transmission plate) electromagnetic waves incident from the top surface (the surface on the positive Z side) in the desired direction. The unit elements 10 and 11 are also called unit cells, unit atoms, reflecting elements, transmitting elements, reflecting units, transmitting units, reflecting devices, transmitting devices, or metastructures.

[0062] Electromagnetic waves can be reflected in any and / or specific directions by changing the impedance characteristics of the radiating elements of the unit elements 10 and 11. The unit element 11 is an example of a first unit element, and the unit element 10 is an example of a second unit element.

[0063] The length L1 of the unit elements 10 and 11 in the Y-axis direction and the length L2 of the unit elements 10 and 11 in the X-axis direction are, for example, the same. For example, the multiple unit elements 10 and 11 have element lengths (lengths L1 and L2) that are 0.05 to 0.5 wavelengths of the target electromagnetic wave. Note that the lengths L1 and L2 are not limited to being 0.05 to 0.5 wavelengths of the electromagnetic wave, but may be 0.1 to 0.5 wavelengths, 0.2 to 0.5 wavelengths, 0.3 to 0.5 wavelengths, 0.4 to 0.5 wavelengths, 0.05 to 0.4 wavelengths, 0.05 to 0.3 wavelengths, or 0.05 to 0.2 wavelengths, or may be within a range between two of the exemplified numerical values.

[0064] The metasurface reflector 1 may also have conductor patterns 101, 102 having at least two different shapes. Furthermore, the metasurface reflector 1 may have two or more unit elements 11 included in the plurality of unit elements 11 each having a conductor pattern 102 (or a conductor portion 104) having at least two different shapes. In this case, quantization of 2 bits or more may be realized by combining the two or more unit elements 11. For example, when 2-bit quantization is realized by combining two or more unit elements 11, the loop shape (phase 0 degrees) of one unit element may be processed to change the phase to 90 degrees, and the cross shape (phase 180 degrees) of the other unit element may be processed to change the phase to 270 degrees.

[0065] The metasurface reflector 1 only needs to have the unit elements 10 and 11 arranged at least one-dimensionally. Although Fig. 1 illustrates an example in which the top view shape of each unit element 10 and 11 is square, this is not limited thereto and may be, for example, a circle or a regular polygon other than a square.

[0066] In addition, in the metasurface reflector 1 shown in Figure 1, cutting processing (wiring cut) is performed on specific unit elements so that unit element 10 changes into unit element 11 according to a phase distribution consisting of 1-bit quantization according to the desired direction at the installation location.

[0067] Fig. 3A is a top view showing a second unit element (unit element 10) according to the present embodiment, Fig. 3B is a perspective view showing the second unit element according to the present embodiment, and Fig. 3C is a side view showing the second unit element according to the present embodiment.

[0068] As shown in FIGS. 3A to 3C, the unit element 10 has a substrate 100, a conductor pattern 101, and a rear surface pattern 105.

[0069] The substrate 100 is, for example, a dielectric substrate (e.g., a resin substrate), and has a conductor pattern 101 formed thereon for reflecting target electromagnetic waves in a desired direction. The substrate 100 has, for example, a thickness corresponding to the design and / or operating frequency, and has a quadrangular shape such as a square when viewed from above. Note that the shape of the substrate 100 when viewed from above is not limited to a quadrangular shape. The shape of the substrate 100 when viewed from above may be any shape that is rotationally symmetric when viewed from above, such as a triangular shape, a polygonal shape with pentagons or more, a circular shape, or an elliptical shape.

[0070] In addition, when the electromagnetic wave redirecting structure is a transparent or semi-transparent metasurface reflector, the substrate 100 may be a transparent plate such as a PET (Poly Ethylene Terephthalate) film.

[0071] The conductor pattern 101 is formed on the surface (first main surface) on the positive side of the Z axis of the substrate 100 , and is formed in a cross shape (cruciform) extending radially from the center of the unit element 10 .

[0072] The back surface pattern 105 is a conductor pattern formed on the back surface (second main surface), which is the surface on the negative side of the Z axis of the substrate 100. The back surface pattern 105 is formed in a solid state on the back surface of the substrate 100. For example, the back surface pattern 105 is a solid conductor pattern formed on the entire back surface of the substrate 100. In this embodiment, the back surface pattern 105 is formed as a ground (GND) layer.

[0073] The back surface pattern 105 does not have to be provided. In other words, the unit elements 10 and 11 of the metasurface reflector 1 may operate as a reflective type with only the surface conductor patterns 101 and 102 formed as the conductor patterns. Also, when the metasurface substrate is a transmissive type, for example, a loop-shaped (annular) conductor pattern is formed as the back surface pattern 105, but the metasurface substrate may operate as a transmissive type with only the surface conductor patterns 101 and 102 formed as the conductor patterns.

[0074] The conductive material that constitutes the conductor pattern 101 and the back surface pattern 105 is not particularly limited, but examples thereof include metal materials such as copper and silver.

[0075] Fig. 4A is a top view showing a first unit element (unit element 11) according to the present embodiment, Fig. 4B is a perspective view showing the first unit element according to the present embodiment, and Fig. 4C is a side view showing the first unit element according to the present embodiment.

[0076] 4A to 4C, the unit element 11 has a substrate 100, a conductor portion 104 including a conductor pattern 102 and a cut portion 103, and a back surface pattern 105. The substrate 100 and the back surface pattern 105 are similar to the substrate 100 and the back surface pattern 105 of the unit element 10, and therefore a description thereof will be omitted. The conductor portion 104 of the unit element 11 and the conductor pattern 101 of the unit element 10 have different shapes. In this embodiment, the conductor portion 104 of the unit element 11 and the conductor pattern 101 of the unit element 10 differ in shape by the amount of processing of the conductor pattern performed in step S30 shown in FIG. 5, which will be described later.

[0077] The conductor patterns 102 are formed so as to extend radially from the center of the unit element 11. In this embodiment, four conductor patterns 102 are formed extending in the up, down, left, and right directions from the center of the unit element 11. The four conductor patterns 102 are spaced apart from one another by cut portions 103. In other words, the four conductor patterns 102 are not electrically connected.

[0078] The cut portion 103 is formed by a cutting process that is performed to change the element length of a pre-formed conductor pattern. In the cutting process, a plurality of conductor patterns (conductor pattern portions) are formed by electrically cutting one conductor pattern from another. The cut portion 103 is formed, for example, by electrically cutting the conductor pattern 101 shown in FIG. 3A or the like by a cutting process. The cut portion 103 is not formed during patterning of the conductor pattern 102, but is formed by a cutting process after the formation of a cross-shaped, solid conductor pattern (for example, the conductor pattern 101). In other words, the cut portion 103 is a portion from which a conductive layer has been removed. The cut portion 103 is an example of a processed portion.

[0079] In this way, the unit element 11 has, in top view, the conductor pattern 102 that extends radially (for example, extends in a straight line) from a predetermined position as the center, and has a processed portion at a predetermined position, which allows the element length of the conductor pattern to be changed.

[0080] Examples of cutting methods include, but are not limited to, laser cutting using laser irradiation, punching, and wire cutting. The cutting location is not limited to the central portion of the unit element 11 (for example, a cross-shaped intersection), and may be any location. The number of cutting locations is not limited to one, and may be multiple.

[0081] For example, in a metasurface reflector 1 with a 1-bit quantized phase distribution, it is ideal to electrically cut (e.g., optimize the element length) the conductor pattern so that the phase of the reflected wave changes by a desired value (e.g., 180 degrees) relative to the phase of the incident wave at the design frequency before and after cutting. The cut portions 103 are formed in positions, shapes, sizes, and numbers that produce the desired phase change. The design frequency may be the frequency (e.g., center frequency) of the electromagnetic wave to be reflected by the metasurface reflector 1.

[0082] The above-mentioned conductor patterns 101 and 102 have a conductor pattern structure that is line-symmetric and point-symmetric (four-fold symmetric) with respect to the central axis in order to achieve the same characteristics for both horizontally and vertically polarized waves, but may also have a linear shape corresponding to either horizontally polarized waves or vertically polarized waves. The center is an example of a predetermined position. Note that the predetermined position is not limited to being the center of the unit elements 10 and 11. Furthermore, the conductor patterns 101 and 102 may have any shape.

[0083] [1-2. Manufacturing Method of Metasurface Reflector] Next, a manufacturing method of the metasurface reflector 1 configured as above will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a flowchart showing a manufacturing method of the metasurface reflector 1 according to this embodiment.

[0084] 5, first, a passive metasurface substrate (here, a metasurface reflector 1a) is fabricated using a basic design pattern (S10). For example, a conductor pattern 101 capable of reflecting electromagnetic waves in a predetermined direction is formed on a substrate 100.

[0085] FIG. 6 is a top view showing a passive metasurface reflector 1a according to this embodiment.

[0086] As shown in Fig. 6, the passive metasurface reflector 1a includes unit elements 10 (array elements) arranged in a two-dimensional periodic structure. While Fig. 6 shows an example in which a cross-shaped conductor pattern 101 is formed on each unit element 10, the conductor pattern 101 of at least one of the unit elements 10 may have a different shape from the conductor patterns 101 of the other unit elements 10. For example, the conductor pattern 101 of each unit element 10 may be formed so that the passive metasurface reflector 1a has desired reflection characteristics (or desired transmission characteristics) for target electromagnetic waves (e.g., sub-terahertz waves above 100 GHz).

[0087] In this way, in step S10, the conductor pattern 101 is formed on the surface layer (first main surface) of the substrate 100, and the shape of the conductor pattern 101 may have a common design for all the unit elements 10, for example.

[0088] Referring again to Figure 5, next, the fabricated passive metasurface substrate (here, metasurface reflector 1a) is stored (S20). In step S30, which will be described later, the conductor pattern is processed to obtain reflection characteristics according to the installation / operation location, etc., so it is sufficient to store only one type (or a small number) of passive metasurface reflectors 1a as the passive metasurface reflector 1a. In other words, there is no need for a design customized to a specific installation / operation location or application, and this can prevent an increase in the types and variations of manufacturing molds or inventory.

[0089] The unit element 10 to be processed is determined (e.g., selected) from among the plurality of unit elements 10 according to a phase distribution quantized with 1+0.5m bits (m: natural number) so that, when the plurality of unit elements 10 are arrayed, the electromagnetic wave is reflected or transmitted in a desired direction. The natural number is an integer equal to or greater than 1. For example, the unit element 10 to be processed may be determined so that the phase distribution when the unit element 10 to be processed is processed approaches the phase distribution quantized with 1+0.5m bits. The method for determining the unit element 10 to be processed is not limited to this. The unit element 10 to be processed only needs to be determined (e.g., selected) from among the plurality of unit elements 10 according to a phase distribution quantized with at least 1 bit.

[0090] Next, in order to obtain reflection characteristics including phase adjustment according to the installation / operation location, etc., the conductor pattern 101 of the stored passive metasurface reflector 1a is processed (S30). That is, in a process after the passive metasurface reflector 1a is fabricated, only arbitrary unit elements are cut and processed according to the phase distribution according to the desired direction at the installation location, etc. of the metasurface reflector 1a.

[0091] This allows the fabrication of a metasurface reflector 1 having desired reflection characteristics according to the installation / operation location, etc. For example, the metasurface reflector 1 is a metasurface reflector whose phase distribution is customized according to the installation / operation location, etc.

[0092] 2 shows an example in which the intersection of one cross-shaped conductor pattern 101 is cut into a cross shape to form four physically unconnected conductor patterns 102. Also, FIG. 2 shows an example in which a cross-shaped cut is made on each of one or more conductor patterns 101 in every other row.

[0093] Examples of processing include laser cutting, punching, and wire cutting, and processing marks remain on the conductor pattern 102 after processing. In the case of laser cutting, the processing marks are, for example, the surface condition (e.g., unevenness) of the cut surface of the conductor pattern 102. The unevenness of the cut surface is different from the unevenness of surfaces other than the cut surface. In other words, by checking the surface of the conductor pattern 102, it is possible to determine whether or not cutting processing has been performed on the conductor pattern 102 in post-processing.

[0094] The processing in step S30 only needs to be performed on at least one unit element 10 out of the multiple unit elements 10 shown in Fig. 6, and may be performed on, for example, only some of the unit elements 10. The processing in step S30 may also be performed on unit elements at periodic positions, such as every one or more columns, every one or more rows, or a staggered pattern. The processing details in step S30 (cut positions, number of cuts, etc.) may be the same for each unit element to be processed, or may be different from each other.

[0095] Note that step S20 may be omitted, and steps S10 and S30 may be performed consecutively.

[0096] In this way, after manufacturing a passive metasurface reflector 1a having a basic design pattern in step S10, the metasurface reflector 1 is formed by changing (controlling) the impedance (phase) of each unit element by changing the physical dimensions of the conductor pattern of only the arbitrary unit elements through wiring processing (wiring cutting or component mounting) in a subsequent process (S30) according to the phase distribution corresponding to the desired direction of the installation / operation location, etc.

[0097] [1-3. Reflection characteristics of metasurface reflector] Next, the reflection characteristics of the metasurface reflector 1 described above will be explained with reference to Figs. 7A to 8. Figs. 7A to 8 show the reflection characteristics (amplitude and phase) before and after processing of the unit elements (unit elements 10 and 11 in this embodiment) by electromagnetic field simulation using the finite integral method. The legends "Open" and "Short" in Figs. 7A to 8 indicate the reflection characteristics of unit elements 10 and 11, respectively. In this verification, the reflection characteristics were evaluated when a plane wave with the XZ plane as the electric field plane was incident on the unit element from the positive side of the Z axis.

[0098] 7A and 7B are diagrams showing the frequency response of amplitude and phase in a unit element before and after processing according to this embodiment, respectively. The reflection characteristics of the unit element are shown in FIGS. 7A and 7B.

[0099] The horizontal axis of Figures 7A and 7B represents the frequency of the electromagnetic wave, the vertical axis of Figure 7A represents the amplitude of the reflected wave, and the vertical axis of Figure 7B represents the phase of the reflected wave (reflection phase). The horizontal axes of Figures 7A and 7B represent the range of 150 to 166 GHz, including a margin around 152 to 164 GHz, which is the frequency band of sub-terahertz waves for 6G. It is expected that similar results will be obtained at frequencies above 100 GHz.

[0100] As shown in FIG. 7A, it can be seen that the amplitude of the reflected electromagnetic wave is within −2 dB for both open and short, resulting in low loss.

[0101] As shown in Figure 7B, when comparing the reflection phases of Open and Short, a phase difference of approximately 180 degrees is obtained within the band (see "Phase difference" in Figure 7B). Note that cutting the conductor pattern reduces the size of the pattern, so the resonant frequency shifts to the high-band side. Also, Figure 7B shows that unit elements 10 and 11 have different phase characteristics with respect to the target electromagnetic wave. Also, Figure 7B shows that processing one unit element from Open to Short to the other can change the phase characteristics with respect to the target electromagnetic wave.

[0102] 7A and 7B, the processing of the conductor pattern (here, cutting) can change the reflection phase by 180 degrees with low loss. Also, as shown in Fig. 7A and 7B, it can be seen that 1-bit quantization (changing the phase by 180 degrees, also called 1-bit phase quantization) can be achieved before and after cutting the conductor pattern.

[0103] Note that the quantization performed before and after the cutting process is not limited to 1-bit quantization. For example, 1.5-bit quantization, which changes the phase by 120 degrees and 240 degrees; 2-bit quantization, which changes the phase by 90 degrees, 180 degrees, and 270 degrees; 2.5-bit quantization, which changes the phase by 60 degrees, 120 degrees, 180 degrees, 240 degrees, and 30 degrees; and 3-bit quantization, which changes the phase by 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees, may be performed. The quantization method to be used can be adjusted depending on which one or more unit elements 10 are selected as the processing target from among the multiple unit elements 10 shown in FIG. 6 . The unit elements to be processed may be determined according to a phase distribution quantized by 0.5 + 0.5n (n: natural number) bits so that the unit elements reflect or transmit electromagnetic waves in the desired direction when arrayed. Note that natural numbers are integers greater than or equal to 1.

[0104] In the case of a metasurface reflector 1, one or more first unit elements to be processed may be determined from the multiple unit elements 10 based on the phase distribution of the reflected wave from the metasurface reflector 1 for each processing method so as to reflect the electromagnetic wave in the desired direction.

[0105] The unit elements before and after processing differ in phase by 180 / (0.5 + 0.5n) degrees (n: natural number). For example, when performing 2-bit quantization, the phase of the first unit element differs from the phase of the second unit element by 90 degrees, 180 degrees, and 270 degrees. For example, the unit element 11 has n phases (n: natural number) in the target electromagnetic wave, and the n phases of the unit element 11 differ from the phase of the electromagnetic wave in the unit element 10 by 180 / (0.5 + 0.5n) degrees.

[0106] FIG. 8 is a diagram showing the results of an electromagnetic field simulation of bistatic radar cross section (RCS) for the metasurface reflector 1 according to this embodiment. FIG. 8 shows the reflection characteristics of the metasurface reflector 1 for 158 GHz electromagnetic waves, with the horizontal axis representing the reflection angle based on the direction perpendicular to the surface of the metasurface reflector 1 (the Z-axis direction), and 0 degrees representing the reflection of the electromagnetic wave toward the positive side of the Z-axis. The vertical axis in FIG. 8 represents bistatic radar cross section (RCS). The bistatic RCS represents the radar cross section when the positions of the transmitting and receiving antennas for the electromagnetic wave are different.

[0107] The dashed line indicates the reflection characteristics of the metasurface reflector 1a in the conventional example (see Figure 6), and the solid line indicates the reflection characteristics of the metasurface reflector 1 according to this embodiment (see Figure 2). The plane incident wave is assumed to be incident on the surface of the metasurface reflector 1 along the Z-axis direction.

[0108] As shown in Figure 8, the metasurface reflector 1a has a directional pattern mainly in the front direction (reflecting electromagnetic waves mainly in the front direction), but the metasurface reflector 1 is able to reflect electromagnetic waves mainly in the ±45-degree direction by cutting. In other words, it can be seen that by processing the conductor pattern, the reflection direction of the electromagnetic waves can be changed mainly in the 45-degree direction. The reflection direction is affected by the processing details of the conductor pattern. In other words, by adjusting the processing details of the conductor pattern, it is possible to realize a metasurface reflector 1 that can reflect electromagnetic waves in any desired direction.

[0109] The incident wave is not limited to the front direction, but may be obliquely incident or may be a spherical wave incident in the near field. Furthermore, by using a metasurface reflector consisting of multiple unit elements (with different reflection phases in the unit elements), it is possible to change the reflection direction of the electromagnetic wave from 15 degrees to 45 degrees.

[0110] As described above, the metasurface reflector 1 can achieve wide bandwidth and low loss even in high frequency bands above 100 GHz, while reducing the number of design patterns and product varieties.

[0111] (Variation 1 of Embodiment 1) Below, a unit element according to this variation will be described with reference to Figures 9A to 11B. Also, Figures 9E to 9P are diagrams showing examples of at least two types of element shaped portions. Note that the following description will focus on differences from embodiment 1, and descriptions of content that is the same as or similar to embodiment 1 will be omitted or simplified.

[0112] In the conductor patterns 101 and 102 according to the first embodiment, in order to realize a wider frequency band, conductor patterns consisting of multiple shapes (with or without electrical connection) may be formed, and in this modified example, other examples of the conductor pattern of the first unit element and the back surface pattern will be described.

[0113] 9A to 9P are top views showing examples of the conductor portion of the first unit element (unit elements 11a to 11p) according to this modification. Any of the unit elements 11a to 11p shown in FIGS. 9A to 9P below may be used in place of the unit element 11 of the metasurface reflector 1 according to embodiment 1. Furthermore, the metasurface reflector 1 may have two or more unit elements 11a to 11p shown in FIGS. 9A to 9P.

[0114] 9A, the unit element 11a has a conductor pattern 102a formed radially from the center of the substrate 100 toward the vertex of the substrate 100, and a cut portion 103a cut in a cross shape at the center. The cut portion 103a is formed in step S30 shown in FIG. 5. The conductor pattern 102a and the cut portion 103a form a conductor portion.

[0115] As shown in Fig. 9B, the unit element 11b has a conductor pattern 102b having a Jerusalem cross shape and a cut portion 103b cut in a cross shape at the center. The conductor pattern 102b has a T-shape formed radially from the center of the substrate 100 toward the side of the substrate 100. The cut portion 103b is formed in step S30 shown in Fig. 5. The conductor portion is formed by the conductor pattern 102b and the cut portion 103b.

[0116] 9C , the unit element 11c includes a conductor pattern portion 102c1 formed radially from the center of the substrate 100 toward the vertex of the substrate 100, an arc-shaped conductor pattern portion 102c2 connected to the end of the conductor pattern portion 102c1 on the outer periphery of the substrate 100, a cut portion 103c1 cut in a cross shape at the center, and a cut portion 103c2 between the conductor pattern portions 102c2. The conductor portion is formed by the conductor pattern portions 102c1 and 102c2 and the cut portions 103c1 and 103c2. The cut portion 103c1 is formed by cutting the cross-shaped conductor pattern in step S30 shown in FIG. 5 , and the cut portion 103c2 is formed by cutting the circular conductor pattern in step S30 shown in FIG. 5 .

[0117] 9D, the unit element 11d has a conductor pattern 102d formed in a fan shape on the substrate 100 and a cut portion 103d cut in a cross shape. The conductor pattern 102d and the cut portion 103d form a conductor portion. The cut portion 103d is formed by cutting the circular conductor pattern in step S30 shown in FIG.

[0118] As shown in Fig. 9E, the unit element 11e has a rectangular loop-shaped conductor pattern 102e in addition to the unit element 11 of Fig. 4A. It can also be said that the unit element 11e has a cross-shaped conductor pattern 102 (an example of an element-shaped portion) and a cut portion 103 inside the rectangular loop-shaped conductor pattern 102e (an example of an element-shaped portion). The conductor patterns 102 and 102e and the cut portion 103 form a conductor portion. The conductor pattern 102e is formed in step S10 shown in Fig. 5.

[0119] As shown in Fig. 9F, the unit element 11f includes cut portions 103f provided on each side of the conductor pattern 102 in addition to the unit element 11e of Fig. 9E. It can also be said that the unit element 11f includes cut portions 103f that divide the loop-shaped conductor pattern 102e into four L-shaped conductor patterns 102f. The conductor portion is formed by the conductor patterns 102 and 102f (an example of an element-shaped portion) and the cut portions 103 and 103f. The cut portions 103f are formed by cutting the loop-shaped conductor pattern 102e in step S30 shown in Fig. 5.

[0120] As shown in Fig. 9G, the unit element 11g has cut portions 103g provided at each corner of the conductor pattern 102 in addition to the unit element 11e of Fig. 9E. It can also be said that the unit element 11g has cut portions 103g that divide the loop-shaped conductor pattern 102e into four rod-shaped conductor patterns 102g (an example of an element-shaped portion). The conductor patterns 102 and 102g and the cut portions 103 and 103g form a conductor portion. The cut portions 103g are formed by cutting the loop-shaped conductor pattern 102e in step S30 shown in Fig. 5.

[0121] 9H, the unit element 11h has a rectangular loop-shaped conductor pattern 102e in addition to the unit element 11d of FIG. 9D. It can also be said that the unit element 11h has a fan-shaped conductor pattern 102d inside the rectangular loop-shaped conductor pattern 102e. The conductor patterns 102d and 102e and the cut portion 103d form a conductor portion.

[0122] As shown in Fig. 9I, the unit element 11i has, in addition to the unit element 11e of Fig. 9E, a rectangular loop-shaped conductor pattern 102i (an example of an element-shaped portion) arranged to surround the conductor pattern 102e. It can also be said that the unit element 11i has the conductor patterns 102, 102e, and the cut portion 103 inside the rectangular loop-shaped conductor pattern 102i. The conductor patterns 102, 102e, and 102i and the cut portion 103 form a conductor portion. The conductor pattern 102i is formed in step S10 shown in Fig. 5.

[0123] As shown in Figure 9J, the unit element 11j has, in addition to the unit element 11f of Figure 9F, an L-shaped conductor pattern 102j (an example of an element-shaped portion) and a cut portion 103j that are arranged to surround the conductor pattern 102f and the cut portion 103f. It can also be said that the unit element 11j has a cut portion 103j that divides the loop-shaped conductor pattern into four L-shaped conductor patterns 102j. The cut portions 103f and 103j are arranged side by side in the X-axis direction and the Y-axis direction. The cut portion 103j is formed by cutting the loop-shaped conductor pattern in step S30 shown in Figure 5.

[0124] As shown in Figure 9K, in addition to the unit element 11g of Figure 9G, the unit element 11k has an L-shaped conductor pattern 102j and cut portion 103j (conductor pattern 102j and cut portion 103j shown in Figure 9J) arranged to surround the conductor pattern 102g and cut portion 103g.

[0125] As shown in FIG. 9L, the unit element 11l has, in addition to the unit element 11h of FIG. 9H, a conductor pattern 102i (conductor pattern 102i shown in FIG. 9I) in the shape of a square loop that is arranged to surround the conductor pattern 102e.

[0126] As shown in Fig. 9M, the unit element 11m has a circular loop-shaped conductor pattern 102m in addition to the unit element 11 of Fig. 4A. It can also be said that the unit element 11m has a cross-shaped conductor pattern 102 and a cut portion 103 inside the circular loop-shaped conductor pattern 102m (an example of an element-shaped portion). The conductor patterns 102 and 102m and the cut portion 103 form a conductor portion. The conductor pattern 102m is formed in step S10 shown in Fig. 5.

[0127] 9N, the unit element 11n has, in addition to the unit element 11m of FIG. 9M, a cut portion 103n that forms four arc-shaped conductor patterns 102n (an example of an element-shaped portion). It can also be said that the unit element 11n has a cut portion 103n that divides the loop-shaped conductor pattern 102m into four arc-shaped conductor patterns 102n. The conductor portion is formed by the conductor patterns 102 and 102n and the cut portions 103 and 103n. The cut portion 103n is formed by cutting the loop-shaped conductor pattern 102m in step S30 shown in FIG.

[0128] 9O, the unit element 11o has, in addition to the unit element 11m of FIG. 9M, a circular loop-shaped conductor pattern 102o (an example of an element-shaped portion) arranged to surround the conductor pattern 102m. It can also be said that the unit element 11o has the conductor patterns 102 and 102m and the cut portion 103 inside the circular loop-shaped conductor pattern 102o. The conductor pattern 102o is formed in step S10 shown in FIG. 5.

[0129] As shown in FIG. 9P, a unit element 11p has a circular loop-shaped conductor pattern 102m (conductor pattern 102m shown in FIG. 9M) in addition to the unit element 11d of FIG. 9D.

[0130] Although the above describes an example in which the conductor patterns formed on the first and second main surfaces of the substrate 100 are solid conductor patterns (solid electrodes), for example, to increase visible light transmittance (transparency), the conductor pattern may be a metal mesh (fine wiring) such as a lattice-shaped copper mesh or silver mesh. The lattice shape is not limited to a quadrilateral shape such as a square or a diamond, and may be, for example, a triangular shape, a polygonal shape with pentagons or more, a circular shape, or an elliptical shape. An example of a metal mesh conductor pattern formed on the first main surface will be described with reference to FIGS. 10A and 10B , and an example of a metal mesh conductor pattern (rear surface pattern) formed on the second main surface will be described with reference to FIGS. 11A and 11B .

[0131] The conductor pattern portion 102c2 and the conductor patterns 102e, 102f, 102i, 102j, 102m, 102n, and 102o shown above are examples of loop-shaped portions. The conductor pattern 102 is an example of a radiating portion that is disposed inside the loop-shaped portion and has a radial shape.

[0132] 10A and 10B are top views showing other examples of the conductor portion of the first unit element according to this modified example.

[0133] As shown in FIG. 10A , the unit element 11q includes a cross-shaped metal mesh conductor pattern 102q1 (an example of an element-shaped portion), a rectangular loop-shaped metal mesh conductor pattern 102q2 (an example of an element-shaped portion), and a cross-shaped cut portion 103q at the intersection of the conductor pattern 102q1. The conductor patterns 102q1 and 102q2 and the cut portion 103q form a conductor portion. The conductor patterns 102q1 and 102q2 are formed in step S10 shown in FIG. 5 , and the cut portion 103q is formed in step S30 shown in FIG. 5 . The conductor patterns 102q1 and 102q2 have a mesh structure. Furthermore, transparency can be improved by using, for example, a PET (Poly Ethylene Terephthalate) film for the substrate 100.

[0134] As shown in FIG. 10B , the unit element 11r includes a conductor pattern portion 102r1 (an example of an element-shaped portion) formed radially from the center of the substrate 100 toward each edge of the substrate 100, a conductor pattern portion 102r2 (an example of an element-shaped portion) formed to connect circumferentially adjacent conductor pattern portions 102r1, a rectangular loop-shaped conductor pattern portion 102r3 (an example of an element-shaped portion) arranged to surround the conductor pattern portions 102r1 and 102r2, and a cut portion 103r provided in the conductor pattern portion 102r2. The conductor pattern portion 102r2 is provided in a straight line connecting circumferentially adjacent conductor pattern portions 102r1, and the cut portion 103r is provided to cut the conductor pattern portion 102r2. The cut portion 103r is formed to change the circumferentially adjacent conductor pattern portions 102r1 from a state in which they are connected via the conductor pattern portion 102r2 to a state in which they are not connected.

[0135] This allows for robustness in the element shape, taking into account the accuracy of positional deviations in laser cutting.

[0136] The conductor pattern portions 102r1, 102r2, and 102r3 and the cut portion 103r form a conductor portion. The conductor pattern portions 102r1, 102r2, and 102r3 are formed in step S10 shown in FIG. 5, and the cut portion 103r is formed in step S30 shown in FIG.

[0137] 11A and 11B are bottom views showing examples of the back surface pattern of the unit element according to this modification. For example, when a metal mesh conductor pattern is formed on the first main surface shown in FIGS. 10A and 10B, the back surface pattern shown in FIGS. 11A and 11B is formed on the back surface of the substrate 100. In addition, either of the unit elements 10 and 11 according to the first embodiment may have at least one of the metal mesh conductor pattern and the back surface pattern shown in FIGS. 11A and 11B below. Note that the back surface patterns in FIGS. 11A and 11B are conductor patterns formed when the device is a metasurface reflector, and a different conductor pattern may be formed when the device is a metasurface transmission plate.

[0138] As shown in Figure 11A, the back surface pattern 105s of the unit element 11s may be a metal mesh conductor pattern extending in the X-axis and Y-axis directions, and as shown in Figure 11B, the back surface pattern 105t of the unit element 11t may be a metal mesh conductor pattern extending in a direction intersecting the X-axis and Y-axis directions.

[0139] This allows the mesh direction / inclination of the conductor patterns on the front and back surfaces to be rotated (shifted relatively) by up to 45 degrees, thereby preventing moire and improving visible light transmittance (transparency).

[0140] (Variation 2 of Embodiment 1) A unit element according to this variation will be described below with reference to Figures 12A to 12E. Note that the following description will focus on differences from Embodiment 1, and descriptions of content that is the same as or similar to Embodiment 1 will be omitted or simplified. This variation shows a conductor pattern formed by punching.

[0141] 12A to 12E are top views showing examples of the conductor portion of the first unit element according to this modified example.

[0142] 12A to 12D show conductor portions formed by punching out areas including intersections of conductor patterns formed in a cross shape.

[0143] The unit element 11u in FIG. 12A includes a rod-shaped conductor pattern 102u and a punched-out portion 103u formed by punching out a rectangular shape and removing the metal material.

[0144] A unit element 11v in FIG. 12B has a rod-shaped conductor pattern 102v and a punched-out portion 103v where a circular punching has been performed and metal material has been removed.

[0145] The unit element 11w in FIG. 12C has an L-shaped conductor pattern 102w and a punched-out portion 103w where metal material has been removed by punching out in a linear (diagonal) pattern.

[0146] A unit element 11x in FIG. 12D has a rod-shaped conductor pattern 102x and a punched-out portion 103x where metal material has been removed by punching out in a straight line (diagonal line).

[0147] A unit element 11y in FIG. 12E has a semicircular conductor pattern 102y and a punched-out portion 103y where metal material has been removed by punching out in a linear (diagonal) pattern.

[0148] As described above, in this modification, in step S30 shown in FIG. 5, the conductor pattern formed in step S10 is removed by blanking.

[0149] (Variation 3 of Embodiment 1) Below, a unit element according to this variation will be described with reference to Figures 13A to 13H. Note that the following description will focus on differences from Embodiment 1, and descriptions of content that is the same as or similar to Embodiment 1 will be omitted or simplified. In this variation, an example of 8 states of 3-bit quantization will be described.

[0150] 13A to 13H are top views showing examples of conductor portions of first unit elements (unit elements 12a to 12h) according to this embodiment, with Fig. 13A showing the conductor pattern before processing.

[0151] Fig. 13A shows a metal mesh conductor pattern having a Jerusalem cross shape. Figs. 13B to 13H show examples in which cuts are formed in the Jerusalem cross conductor pattern shown in Fig. 13A. An example of 3-bit quantization (8 states) will be described with reference to Figs. 13A to 13H. By converting to multi-value, quantization lobes can be reduced.

[0152] 13A , the unit element 12a has a first conductor pattern portion 112a1 extending from the center of the substrate 100 toward the side of the substrate 100, and a second conductor pattern portion 112a2 arranged to intersect (for example, perpendicular to) the first conductor pattern portion 112a1 in a plan view. No cut portion is formed in the unit element 12a.

[0153] The unit elements 12b to 12d in FIGS. 13B to 13D further have cut portions in the second conductor pattern portion 112a2 compared to the unit element 12a shown in FIG. 13A. The cut portions 113b of the unit element 12b shown in FIG. 13B are formed on the positive and negative sides of the X-axis of the lattice at both ends of the second conductor pattern portion 112b. The cut portions 113c of the unit element 12c shown in FIG. 13C are formed on the positive and negative sides of the X-axis of the lattice one grid inward from both ends of the second conductor pattern portion 112c. The cut portions 113d of the unit element 12d shown in FIG. 13D are formed on the positive and negative sides of the X-axis of the lattice two grids inward from both ends of the second conductor pattern portion 112d. This divides one second conductor pattern portion 112a2 into three electrically disconnected portions.

[0154] The unit elements 12e to 12h in FIGS. 13E to 13H further have cut portions in the first conductor pattern portion 112a1 compared to the unit element 12d shown in FIG. 13D.

[0155] The cut portions 113e of the unit element 12e shown in Fig. 13E are formed on the positive and negative sides of the Y-axis of the lattice at each end of the cross-shaped first conductor pattern portion 112e. The cut portions 113f of the unit element 12f shown in Fig. 13F are formed on the positive and negative sides of the Y-axis of the lattice one space inward from each end of the cross-shaped first conductor pattern portion 112f. This lattice is common to the first conductor pattern portion 112f and the second conductor pattern portion 112d.

[0156] The cut portions 113g of the unit element 12g shown in FIG. 13G are formed on the positive and negative sides of the Y axis of the lattice two positions inward from each end of the cross shape of the first conductor pattern portion 112g.

[0157] The cut portions 113h of the unit element 12h shown in FIG. 13H are formed on the positive and negative sides of the Y axis of the lattice three positions inward from each end of the cross shape of the first conductor pattern portion 112h.

[0158] As shown in Figures 13A to 13H, the phase change of each unit element can be made different by changing the presence or absence of cuts and the cut positions. By having one metasurface reflector have the unit elements shown in Figures 13A to 13H, it is possible to give the one metasurface reflector multiple phase changes.

[0159] The cut portions 113b to 113h are formed in step S30 shown in FIG.

[0160] (Embodiment 2) A unit element according to this embodiment will be described below with reference to Figures 14A to 15C. Note that the following description will focus on differences from embodiment 1, and descriptions of content that is the same as or similar to embodiment 1 will be omitted or simplified.

[0161] In this embodiment, an example will be described in which, as processing, conductor pattern portions arranged at a distance from each other are connected using a bonding member in step S30 shown in Fig. 5. The metasurface reflector according to this embodiment has unit element 20 shown in Fig. 14A etc. instead of unit element 10 according to embodiment 1, and has unit element 21 shown in Fig. 15A etc. instead of unit element 11.

[0162] Fig. 14A is a top view showing a second unit element (unit element 20) according to the present embodiment, Fig. 14B is a perspective view showing the second unit element according to the present embodiment, and Fig. 14C is a side view showing the second unit element according to the present embodiment.

[0163] 14A to 14C, the unit element 20 has a substrate 200, a conductor pattern 201, an unformed portion 202, and a back surface pattern 205. The substrate 200 and the back surface pattern 205 are similar to the substrate 100 and the back surface pattern 105 according to the first embodiment, and therefore a description thereof will be omitted.

[0164] The conductor pattern 201 is formed on the surface (first main surface) on the positive side of the Z axis of the substrate 200 , and is formed in a cross shape (cruciform) extending radially from the center of the unit element 20 .

[0165] 14A, the unformed portions 202 are regions where no conductor patterns are formed, and are arranged at intersections of the cross-shaped conductor patterns 201. The unformed portions 202 may be formed such that the four radial conductor patterns 201 are spaced apart from one another.

[0166] The shape of the unformed portion 202 in top view is not limited to a square shape, but may be a circle, a polygon, or the like.

[0167] The conductor pattern 201 and the unformed portion 202 are formed, for example, in step S10 shown in Fig. 5. For example, the conductor pattern 201 and the unformed portion 202 are formed by patterning in step S10.

[0168] Fig. 15A is a top view showing a first unit element (unit element 21) according to this embodiment, Fig. 15B is a perspective view showing the first unit element according to this embodiment, and Fig. 15C is a side view showing the first unit element according to this embodiment.

[0169] 15A to 15C, the unit element 21 has a substrate 200, a conductor portion 204 including a conductor pattern 201 and a connection portion 203, and a back surface pattern 205. The unit element 21 is formed by arranging the connection portion 203 so as to cover the unformed portion 202 of the unit element 20.

[0170] The conductor patterns 201 are formed so as to extend radially from the center of the unit element 21. In this embodiment, four conductor patterns 201 are formed so as to extend in the up, down, left, and right directions from the center of the unit element 21. The four conductor patterns 201 are arranged so as to be spaced apart from one another by connecting portions 203.

[0171] The connection portion 203 may be configured to include at least one of silver paste, solder, an inductance element, a capacitance element, a conductive adhesive, a conductive polymer, and wire bonding, but is not limited to these. The connection portion 203 is realized, for example, by mounting a component at a desired position on the substrate 200 in step S30 shown in Fig. 5. Note that the connection portion 203 does not include an element capable of dynamically varying impedance, such as a diode.

[0172] The connection portion 203 is realized by a component mounted by a mounting process to change the element length of the pre-formed conductor pattern. By having the connection portion 203, for example, the element length of the pre-formed conductor pattern can be increased.

[0173] The size of the connecting portion 203 in a top view is, for example, larger than the size of the unformed portion 202 in a top view. The connecting portion 203 is arranged so as to cover the unformed portion 202 in a top view. The connecting portion 203 is an example of a processed portion.

[0174] In this embodiment, phase control is performed by electrically connecting at least two of the four conductor patterns 201 arranged at a distance using component mounting, changing the element length of the conductor patterns, and shifting the resonant frequency of the unit element 21 to a lower range.

[0175] (Other Embodiments) While the electromagnetic wave redirecting structures (mainly metasurface reflectors) according to one or more aspects have been described above based on the respective embodiments, the present disclosure is not limited to these respective embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceivable by those skilled in the art to the present embodiments and forms constructed by combining components of different embodiments may also be included in the present disclosure.

[0176] For example, in each of the above embodiments, an example has been described in which one unit element is provided with either a cut portion or a connection portion as a processed portion, but this is not limited to this, and a mixture of cut portions and connection portions may also be used.

[0177] Furthermore, the unit elements according to the above embodiments may be used in a phased array antenna, a reflect array, a metasurface reflector / transmitter, or a RIS, an IRS, or a LIS. The conductor layers of the radiating element, bias line, and ground layer in the unit element may be solid electrodes or metal meshes.

[0178] Furthermore, the electromagnetic wave direction-changing structure according to the above-mentioned embodiments can be used in unit elements that reflect / transmit electromagnetic waves, antenna devices that radiate and / or receive electromagnetic waves, and reflector arrays that reflect electromagnetic waves, metasurface reflector / transmitter plates, or reflector / transmitter plate devices such as RIS, IRS, and LIS.

[0179] Furthermore, the order of the steps in the manufacturing method of the electromagnetic wave direction-changing structure described in each of the above embodiments may be interchanged. Furthermore, the steps in the manufacturing method of the electromagnetic wave direction-changing structure described in each of the above embodiments may be performed in a single process or in separate processes. "Performed in a single process" is intended to include the steps being performed using a single device, being performed consecutively, or being performed at the same location. "Separate processes" is intended to include the steps being performed using separate devices, being performed at different times (e.g., on different days), or being performed at different locations.

[0180] The present disclosure is useful for electromagnetic wave redirection structures such as metasurface reflectors.

[0181] 1, 1a Metasurface reflector (electromagnetic wave direction changing structure) 10, 20 Unit element (second unit element) 11, 11a, 11b, 11c, 11d, 11e, 11f, 11g, 11h, 11i, 11j, 11k, 11l, 11m, 11n, 11o, 11p, 11q, 11r, 11s, 11t, 11u, 11v, 11w, 11x, 11y, 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, 21 Unit element (first unit element) 100, 200 Substrate 101, 102, 102a, 102b, 102d, 102e, 102f, 102g, 102i, 102j, 102m, 102n, 102o, 102q1, 102q2, 102u, 102v, 102w, 102x, 102y, 201 Conductor patterns 102c1, 102c2, 102r1, 102r2, 102r3, Conductor pattern portions 112a1, 112e, 112f, 112g, 112h First conductor pattern portions 112a2, 112b, 112c, 112d Second conductor pattern portions 103, 103a, 103b, 103c1, 103c2, 103d, 103f, 103g, 103j, 103m, 103n, 103q, 103r, 113b, 113c, 113d, 113e, 113f, 113g, 113h Cut portion (processed portion) 103u, 103v, 103w, 103x, 103y Punched portion (processed portion) 104, 204 Conductor portion 105, 105s, 105t, 205 Back surface pattern 202 Unformed portion 203 Connection portion (processed portion) L1, L2 Length

Claims

1. An electromagnetic wave direction-changing structure in which a plurality of unit elements, each having a substrate and a conductor pattern formed on a first main surface of the substrate, are arranged side by side at least one-dimensionally, wherein one or more first unit elements of the plurality of unit elements comprise the substrate, the conductor pattern, and a conductor portion having a processed portion obtained by processing a portion of the conductor pattern, and the processed portion has at least one of a cut portion obtained by cutting a portion of the conductor pattern and a connection portion that connects conductor pattern portions formed at a distance from each other in the conductor pattern.

2. The electromagnetic wave direction-changing structure according to claim 1, wherein the processed portion has at least the cut portion, and the cut portion is a portion formed by any one of laser cutting, punching, and wire cutting.

3. The electromagnetic wave redirecting structure according to claim 1, wherein the processed portion has at least the connecting portion, and the connecting portion includes at least one of silver paste, solder, an inductance element, a capacitance element, a conductive adhesive, a conductive polymer, and wire bonding.

4. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the one or more first unit elements are unit elements selected from a plurality of the unit elements in accordance with a phase distribution quantized by at least one bit so that, when the plurality of unit elements are arranged in an array, the electromagnetic wave is reflected or transmitted in a desired direction.

5. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the plurality of unit elements include one or more second unit elements, and the one or more first unit elements and the one or more second unit elements have the conductor pattern extending radially from a predetermined position as a center in top view, and the one or more first unit elements have the processed portion at the predetermined position.

6. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the one or more first unit elements have the conductor portion that is line-symmetric and point-symmetric with a predetermined position as a central axis when viewed from above, and the plurality of unit elements have one or more second unit elements that have the conductor pattern that is line-symmetric and point-symmetric with a predetermined position as a central axis when viewed from above.

7. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the plurality of unit elements have one or more second unit elements in addition to the one or more first unit elements, and the conductor pattern of the one or more first unit elements and the conductor pattern of the one or more second unit elements have different shapes.

8. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the conductor patterns of the plurality of unit elements have at least two types of element-shaped portions.

9. The electromagnetic wave direction-changing structure according to claim 8, wherein the at least two types of element-shaped portions include: a loop-shaped portion having a loop shape; and a radiation portion arranged inside the loop-shaped portion and having a radial shape.

10. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the plurality of unit elements have one or more second unit elements in addition to the one or more first unit elements, and the one or more first unit elements and the one or more second unit elements have different phase characteristics with respect to the target electromagnetic wave.

11. The electromagnetic wave direction-changing structure according to claim 10, wherein the one or more first unit elements have n phases (n: natural number) in the target electromagnetic wave, and the n phases of the one or more first unit elements differ from the phases of the electromagnetic wave in the one or more second unit elements by 180 / (0.5+0.5n) degrees.

12. The electromagnetic wave redirecting structure according to any one of claims 1 to 3, further comprising a GND layer on a second main surface of the substrate opposite to the first main surface.

13. An electromagnetic wave direction-changing structure according to any one of claims 1 to 3, wherein the plurality of unit elements have an element length of 0.05 to 0.5 wavelengths of the target electromagnetic wave.

14. A method for manufacturing an electromagnetic wave direction-changing structure in which a plurality of unit elements, each having a substrate and a conductor pattern formed on a main surface of the substrate, are arranged in a line at least one-dimensionally, comprising the steps of: preparing a structure in which a plurality of the unit elements, each having the conductor pattern formed thereon, are arranged in a line; processing the conductor pattern in accordance with desired reflection characteristics or transmission characteristics for target electromagnetic waves; and the processing includes at least one of cutting a part of the conductor pattern for at least one unit element out of the plurality of unit elements; and joining conductor pattern portions of the conductor pattern that are formed at a distance from each other.

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