Metasurfaces and Communication Devices

Abstract

This application relates to the field of communication technology and provides a metasurface and a communication device. The metasurface includes multiple metasurface units, the number of which is at least 2 to the power of N. The phases of each metasurface unit are sequentially differed by a preset phase difference. The difference between the preset phase difference and a first ratio is less than a phase error threshold. The first ratio is 2π to 2 to the power of N, where N is the number of encoded bits of the metasurface. The size of the first metasurface unit is positively correlated with the ratio of the encoding period to 2 to the power of N; the encoding period is positively correlated with the ratio of 2π to the phase gradient; the phase gradient is positively correlated with the product of the first difference and the second ratio; the first difference is positively correlated with the difference between the sine of the exit angle and the sine of the incident angle; and the second ratio is positively correlated with the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave. Therefore, the metasurface can reflect the incident wave at a preset exit angle.

Description

Technical Field

[0001] This application belongs to the field of communication technology, and in particular relates to a metasurface and a communication device. Background Technology

[0002] With the development of technology, people have increasingly higher requirements for communication quality. However, in traditional cellular network deployments, areas with coverage gaps may appear, forming network coverage blind spots, such as areas shaded by tall buildings or vegetation. This results in poor signal quality for terminals located in these areas. To address this issue, metasurfaces, as two-dimensional metamaterials, are often placed between base stations and network coverage blind spots because they can flexibly manipulate the electromagnetic properties of the channel environment. They are used to control the direction of signal transmission, ensuring that the transmitted signal reaches the network coverage blind spot, thereby increasing the network coverage area.

[0003] In traditional technologies, metasurfaces or active smart metasurfaces, including digital phased array units, are typically placed between a base station and the location where the signal is expected to arrive to alter the signal transmission characteristics and control the signal transmission direction. For example, in a metasurface including digital phased array units, each metasurface unit contains a DC bias line and a PIN (Positive Intrinsic Negative) diode. The control system controls the conduction and disconnection of the PIN diode through the DC bias line to change the response of the metasurface unit, thereby changing the phase of the signal input to the metasurface and ultimately transmitting the signal to the desired location.

[0004] However, because each metasurface unit in a metasurface including a digital phase control unit is connected to a control system, resulting in numerous lines, it is not easy to deploy in practical applications. In contrast, in an active smart metasurface, each metasurface unit integrates an active power amplifier, which increases system power consumption and manufacturing costs. Summary of the Invention

[0005] This application provides a metasurface and a communication device. The phase of an incident wave can be changed by a metasurface containing multiple metasurface units whose phases are sequentially differed by a preset phase difference, so that the incident wave is reflected at a preset exit angle. This can solve the problems in the prior art where metasurface units are difficult to deploy due to the connection to the control system and the large number of lines, and / or the high power consumption and cost caused by the integration of active power amplifiers in the metasurface.

[0006] In a first aspect, embodiments of this application provide a metasurface, the metasurface comprising a plurality of metasurface units, the number of the plurality of metasurface units being at least 2 to the power of N, the phases corresponding to each of the plurality of metasurface units being sequentially differed by a preset phase difference, the difference between the preset phase difference and a first ratio being less than a phase error threshold, the first ratio being 2π to 2 to the power of N, where N is the encoding bit of the metasurface;

[0007] The size of the first metasurface unit is positively correlated with the ratio of the encoding period to the power of 2. The first metasurface unit is any one of the plurality of metasurface units. The encoding period is positively correlated with the ratio of 2π to the phase gradient. The phase gradient is positively correlated with the product of the first difference and the second ratio. The first difference is positively correlated with the difference between the sine of the exit angle and the sine of the incident angle. The second ratio is positively correlated with the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave.

[0008] In this application, the exit angle can be preset, and then the size of the metasurface unit can be determined based on the known wavelength and angle of the incident wave. Multiple metasurface units with corresponding phases differing by a preset phase difference can form a metasurface, which can reflect the incident wave of the corresponding wavelength at a predetermined exit angle. The metasurface provided in this application contains multiple corresponding metasurface units with corresponding phases differing by a preset phase difference, forming a specific phase gradient. This can change the phase of the incident wave, causing it to exit at a preset exit angle, thus achieving the effect of manipulating the incident wave. Because the metasurface units in this application can achieve different phases themselves, no control system is required. During use, they only need to be combined and fixed according to the actual situation, without complex wiring, making deployment easy. Furthermore, the metasurface in this application is a passive metasurface, eliminating the need for an integrated active power amplifier, which reduces power consumption and manufacturing costs.

[0009] In some embodiments, the size of the first metasurface unit is the ratio of the coding period to the power of 2, the coding period is the ratio of 2π to the phase gradient, the phase gradient is the product of a first difference and a second ratio, the first difference is the difference between the sine of the exit angle and the sine of the incident angle, and the second ratio is the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave.

[0010] The dimensions of metasurface units can be accurately calculated using the incident angle, the exit angle, and the wavelength of the incident wave. Furthermore, using a variant of the generalized Snell's law of reflection to calculate the dimensions of metasurface units can make the calculation process more efficient and the results more accurate.

[0011] In some embodiments, when the metasurface unit is square, the side length of the metasurface unit is the ratio of the coding period to the power of 2.

[0012] When the shape of the metasurface unit is square, the size of the metasurface can be the side length of the metasurface unit. At the same time, using a square as the shape of the metasurface unit can facilitate the fabrication, arrangement and fixation of the metasurface unit.

[0013] In some embodiments, the length of the metasurface in the polarization direction parallel to the incident wave is greater than or equal to the coding period, and the length of the metasurface in the polarization direction perpendicular to the incident wave is greater than or equal to the wavelength of the incident wave.

[0014] This allows the metasurface to effectively reflect incident waves at a preset exit angle, ensuring the metasurface's reflection effect.

[0015] In some embodiments, the number of metasurface units parallel to the polarization direction of the incident wave is an integer multiple of 2 raised to the power of N, where the integer is greater than 1.

[0016] The reflectivity of a metasurface can be enhanced by stacking multiple rows of metasurface units with continuous phase gradients.

[0017] In some embodiments, the integer is 2.

[0018] Choosing an integer of 2 can effectively enhance the reflection intensity of the metasurface. If the integer chosen is greater than 2, it will not only increase the manufacturing cost but also increase the difficulty of fixing. Therefore, choosing an integer of 2 is more reasonable.

[0019] In some embodiments, the first metasurface unit includes a plurality of metasurface subunits, the first metasurface unit being any one of the plurality of metasurface units, and each of the metasurface subunits having the same phase as the first metasurface unit.

[0020] By setting multiple metasurface sub-units with the same phase as the corresponding metasurface unit, the mutual interference caused by adjacent metasurface units having different phases can be avoided, thus ensuring the reflection effect of the metasurface.

[0021] In some embodiments, each of the plurality of metasurface subunits is square in shape.

[0022] By setting the shape of the metasurface subunit to square, the design, fabrication, and fixation of the metasurface unit can be facilitated.

[0023] In some embodiments, the number of metasurface units in the polarization direction perpendicular to the incident wave is greater than 2, and any two adjacent metasurface units in the polarization direction perpendicular to the incident wave have the same phase.

[0024] The reflective effect of a metasurface can be enhanced by stacking multiple rows of metasurface units.

[0025] In some embodiments, the number of metasurface units perpendicular to the polarization direction of the incident wave is equal to the number of metasurface units parallel to the polarization direction of the incident wave.

[0026] By setting the number of metasurface units perpendicular to the polarization direction of the incident wave to be equal to the number of metasurface units parallel to the polarization direction of the incident wave, the isotropic reflection of the incident wave by the metasurface can be guaranteed, facilitating the superposition of outgoing waves and making the reflection effect of the metasurface on the incident wave better.

[0027] In some embodiments, the angle between one side of the metasurface and the horizontal direction is less than 45°, and the phases of the multiple metasurface units distributed along any side of the metasurface are sequentially differed by a preset phase difference.

[0028] By setting the angle between one side of the metasurface and the horizontal direction to be less than 45°, and by ensuring that the phases of multiple metasurface units distributed along any side of the metasurface are sequentially separated by a preset phase difference, it can be guaranteed that the metasurface after rotating 45° will reflect each polarized wave in the ±45° dual-polarized incident wave at a preset angle, thereby ensuring the reflection effect of the metasurface.

[0029] In some embodiments, the metasurface unit includes a metal patch, a dielectric substrate, and a metal ground plane, wherein the metal patch and the metal ground plane are respectively attached to both sides of the dielectric substrate plane, and the size of the metal patch is smaller than the size of the metasurface unit.

[0030] The subwavelength metasurface unit designed using metal patches, dielectric substrates, and metal ground planes has a simple structure, small size, and is easy to implement.

[0031] In some embodiments, the shape of the metal patch is mirror-symmetric and centrally symmetric.

[0032] Selecting metal patches with mirror-symmetric and centrosymmetric shapes can make the metasurface unit insensitive to the polarization direction of the incident wave and ensure isotropy.

[0033] In some embodiments, the metal patch is square, and the ratio of the side length of the first metal patch to the preset initial side length is a preset scaling factor, wherein the preset scaling factor is phase-dependent with respect to the first metasurface unit.

[0034] Wherein, the first metal patch is the metal patch of the first metasurface unit, and the preset initial side length is greater than or equal to the subwavelength and smaller than the size of the first metasurface unit.

[0035] By scaling the preset initial side length, the first metal patch can realize the phase corresponding to the first metasurface unit, which meets the design requirements of the metasurface unit. This method is simple and fast, improving the efficiency and accuracy of metasurface design.

[0036] Secondly, embodiments of this application provide a communication device, the communication device comprising a plurality of cascaded metasurfaces as described in any one of the first aspects.

[0037] By setting up multiple cascaded metasurfaces, the reflection path of the incident wave can be changed, allowing the incident wave to be transmitted to the desired location.

[0038] In some embodiments, the plurality of metasurfaces are used to progressively adjust the reflection path of the incident wave, wherein the shape of the reflection path is at least one of U-shape, N-shape, L-shape, W-shape, M-shape, V-shape, and Z-shape.

[0039] By placing multiple cascaded metasurfaces at the corners of different reflection paths, the reflection path of the incident wave emitted by the base station can be adjusted step by step, ultimately enabling it to be transmitted to the user terminal. This enhances network coverage and meets the needs for enhanced wireless network coverage in complex environments, such as outdoor coverage obstructed by buildings, indoor winding and narrow passages, tunnels, or mines.

[0040] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the coding sequence corresponding to a first type of metasurface for a horizontally polarized wave, provided in an embodiment of this application.

[0043] Figure 2This application provides a schematic diagram of the coding sequence corresponding to a second type of metasurface for a horizontally polarized wave.

[0044] Figure 3 This application provides a schematic diagram of the coding sequence corresponding to a first type of metasurface for a vertically polarized wave.

[0045] Figure 4 This application provides a schematic diagram of the coding sequence corresponding to a second type of metasurface for a vertically polarized wave.

[0046] Figure 5 This is a schematic diagram of the coding sequence corresponding to the first type of metasurface for a dual-polarized wave, provided in an embodiment of this application.

[0047] Figure 6 This application provides a schematic diagram of the coding sequence corresponding to other metasurfaces for a dual-polarized wave, as shown in the embodiments of this application.

[0048] Figure 7 This application provides a schematic diagram of the coding sequence corresponding to a third type of metasurface for a horizontally polarized wave.

[0049] Figure 8 This application provides a schematic diagram of the coding sequence corresponding to a fourth type of metasurface for a horizontally polarized wave.

[0050] Figure 9 This application provides a schematic diagram of the coding sequence corresponding to a fifth type of metasurface for a horizontally polarized wave.

[0051] Figure 10 This application provides a first type of reflection pattern corresponding to a metasurface.

[0052] Figure 11 This application provides a first reflection pattern of the xoz plane corresponding to a metasurface.

[0053] Figure 12 This application provides a schematic diagram of the coding sequence corresponding to other metasurfaces for a horizontally polarized wave, as shown in the embodiments of this application.

[0054] Figure 13 This is a schematic diagram of the coding sequence corresponding to a second type of metasurface for a dual-polarized wave, provided in an embodiment of this application.

[0055] Figure 14 A schematic diagram of a metasurface provided for an embodiment of this application;

[0056] Figure 15 This application provides a second reflection pattern corresponding to a metasurface.

[0057] Figure 16 This application provides a second reflection pattern for the xoz plane corresponding to a metasurface.

[0058] Figure 17 This application provides a schematic diagram of the coding sequence corresponding to a third type of metasurface for a dual-polarized wave.

[0059] Figure 18 This application provides a schematic diagram of the coding sequence corresponding to a sixth type of metasurface for a horizontally polarized wave.

[0060] Figure 19 This application provides a third type of reflection pattern corresponding to a metasurface.

[0061] Figure 20 This application provides a third reflection pattern for the xoz plane corresponding to a metasurface.

[0062] Figure 21 This is a schematic diagram of the structure of a metasurface unit provided in an embodiment of this application;

[0063] Figure 22 A simulation diagram illustrating a first metasurface unit corresponding to four different phases under four different scaling variables, provided for an embodiment of this application;

[0064] Figure 23 A schematic diagram of a reflection path provided for an embodiment of this application;

[0065] Figure 24 This is a schematic diagram of another reflection path provided in an embodiment of this application. Detailed Implementation

[0066] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0067] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0068] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0069] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0070] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0071] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0072] In traditional technologies, metasurfaces or active smart metasurfaces, including digital phased array units (DPAs), are typically placed between a base station and the desired signal location to alter signal transmission characteristics and control the signal direction. For example, in a DPA-integrated metasurface, each metasurface unit includes a DC bias line and a PIN diode. The control system controls the conduction and disconnection of the PIN diodes via the DC bias line to change the response of the metasurface unit, thereby altering the phase of the signal input to the metasurface and ultimately transmitting the signal to the desired location. However, because each metasurface unit in a DPA-integrated metasurface is connected to the control system, resulting in numerous lines, deployment is difficult in practical applications. Active smart metasurfaces, by integrating active power amplifiers, increase system power consumption and manufacturing costs.

[0073] To address the aforementioned issues, this application provides a metasurface that may include multiple metasurface units. The number of metasurface units may be at least 2 to the power of N. The phase of each metasurface unit may be sequentially differed by a preset phase difference. The difference between the preset phase difference and a first ratio may be less than a phase error threshold. The first ratio may be 2π to 2 to the power of N, where N is the encoding bit of the metasurface.

[0074] Optionally, N can be 2, or it can be 3, 4 or 5, as long as N≥2. This application does not limit this, and will use N=2 as an example for explanation.

[0075] Optionally, the phase error threshold can be a small number, such as 0.1, 0.15 or 0.2, as long as it can guarantee the accuracy of the preset phase difference. This application does not limit this.

[0076] For example, when the encoding bit N of the metasurface is 2, the number of multiple metasurface units can be at least 4, the first ratio can be π / 2, and the phases corresponding to the 4 metasurface units can be successively different by π / 2.

[0077] Optionally, the phase of each metasurface unit in the plurality of metasurface units can be non-fixed, as long as their corresponding phases differ sequentially by a preset phase difference. The value range of the phase corresponding to the reference metasurface unit can be (0, 2π) ± nπ, n = 0, 1, 2, 3... (non-negative integers). The reference metasurface unit can be any one of the plurality of metasurface units, and the phases corresponding to the other metasurface units can be determined by the phases corresponding to the reference metasurface unit differing from the preset phase difference.

[0078] For example, π / 4 can be selected as the phase corresponding to the reference metasurface unit. When N is 2, the phases corresponding to the four metasurface units can be π / 4, 3π / 4, 5π / 4, and 7π / 4, or they can be π / 4, -π / 4, -3π / 4, and -5π / 4, etc. This application does not limit the specific phases corresponding to the metasurface units, as long as they are sequentially differed by a preset phase difference. In the embodiment, the phases corresponding to the four metasurface units are 3π / 4, π / 4, -π / 4, and -3π / 4, respectively, for illustration.

[0079] In this application, the size of the first metasurface unit can be positively correlated with the ratio of the coding period to a power of 2, for example, it can satisfy the following relationship:

[0080]

[0081] Where Ls is the size of the first metasurface unit, Γ is the encoding period, k1 is the first slope, and b1 is the first intercept point.

[0082] The first metasurface unit can be any one of multiple metasurface units.

[0083] Optionally, k1 can be a value such as 1.01, 1.02, or 1.03, and b1 can be a smaller value such as 0.01, 0.02, or 0.03. This application does not limit this; taking k1 as 1 and b1 as 0 as an example, that is, the size of the first metasurface unit can be the ratio of the coding period to a power of 2, which yields:

[0084]

[0085] Optionally, the coding period can be positively correlated with the ratio of 2π to the phase gradient, for example, by satisfying the following relationship:

[0086]

[0087] in, Let be the phase gradient, k2 be the second slope, and b2 be the second intercept point.

[0088] Optionally, k2 can be a value such as 1.01, 1.02, or 1.03, and b2 can be a smaller value such as 0.01, 0.02, or 0.03. This application does not limit this; taking k2 as 1 and b2 as 0 as an example, that is, the coding period can be the ratio of 2π to the phase gradient, which yields:

[0089]

[0090] Optionally, the phase gradient can be positively correlated with the product of the first difference and the second ratio, for example, satisfying the following relationship:

[0091]

[0092] Where A is the first difference, B is the second ratio, k3 is the third slope, and b3 is the third intercept point.

[0093] Optionally, k3 can be a value such as 1.01, 1.02, or 1.03, and b3 can be a smaller value such as 0.01, 0.02, or 0.03. This application does not limit this; taking k3 as 1 and b3 as 0 as an example, the phase gradient can be the product of the first difference and the second ratio, which yields:

[0094]

[0095] Optionally, the first difference can be positively correlated with the difference between the sine of the exit angle and the sine of the incident angle, for example, it can satisfy the following relationship:

[0096] A = k4(sinθ) r -sinθi Formula (7) + b4

[0097] Where, θ r Let θ be the angle of departure. i Let be the angle of incidence, k4 be the fourth slope, and b4 be the fourth intercept point.

[0098] Optionally, k4 can be a value such as 1.01, 1.02, or 1.03, and b4 can be a smaller value such as 0.01, 0.02, or 0.03. This application does not limit this; taking k4 as 1 and b4 as 0 as an example, the first difference can be the difference between the sine of the exit angle and the sine of the incident angle, which yields:

[0099] A = sinθ r -sinθ i Formula (8)

[0100] Optionally, the second ratio can be positively correlated with the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave. For example, the following relationship can be satisfied:

[0101]

[0102] Where, n i λ is the refractive index of the incident interface, λ is the wavelength of the incident wave, k5 is the fifth slope, and b5 is the fifth intercept point.

[0103] Optionally, k5 can be a value such as 1.01, 1.02, or 1.03, and b5 can be a smaller value such as 0.01, 0.02, or 0.03. This application does not limit this; taking k5 as 1 and b5 as 0 as an example, the second ratio can be the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave, which yields:

[0104]

[0105] Optionally, the exit angle can be the reflection angle of the incident wave after it has been reflected by the metasurface.

[0106] Optionally, when k1, b1, k2, b2, k3, b3, k4, b4, k5, and b5 are all 1, the above relationship satisfies the generalized Snell's law of reflection. The mathematical expression of the generalized Snell's law of reflection is:

[0107]

[0108] Optionally, since the metasurface unit has a metallic ground plane, the refractive index of the incident interface is generally 1. Therefore, according to equations (1) to (10), equation (11) can be transformed into:

[0109]

[0110] As can be seen from formula (12), the size of the metasurface unit can be accurately calculated by the incident angle, the exit angle and the wavelength of the incident wave. At the same time, the size of the metasurface unit can be calculated by the variant of the generalized Snell reflection law, which can make the calculation process more efficient and the calculation results more accurate.

[0111] Optionally, when the incident wave is a single-frequency signal, the wavelength of the incident wave can be the wavelength corresponding to the frequency of the incident wave; when the incident wave is a signal within a certain frequency band, the wavelength of the incident wave can be the wavelength corresponding to the center frequency of the frequency band to which the incident wave is located.

[0112] In this application, the required exit angle can be preset, and then the encoding period of the metasurface can be determined based on the known wavelength and angle of the incident wave. The size of the metasurface unit can be further determined through the encoding period. Multiple metasurface units with corresponding phases differing by a preset phase difference can form a metasurface. This metasurface can reflect the incident wave of the corresponding wavelength at a predetermined exit angle. The metasurface provided in this application contains multiple corresponding metasurface units with corresponding phases differing by a preset phase difference, forming a specific phase gradient. This can change the phase of the incident wave, causing it to exit at a preset exit angle, thus achieving the effect of manipulating the incident wave. Because the metasurface units in this application can achieve different phases themselves, no control system is required. In use, they only need to be combined and fixed according to the actual situation, without complex wiring, making deployment easy. At the same time, the metasurface in this application is a passive metasurface, which does not require the integration of an active power amplifier, thus reducing power consumption and manufacturing costs.

[0113] Optionally, the shape of the metasurface unit can be a square or a shape close to a square, such as a rectangle with small differences between adjacent sides. This application uses a square shape as an example for illustration. In this case, the size Ls of the metasurface unit can be the side length of the square, which can be calculated by formula (12). Using a square as the shape of the metasurface unit can facilitate the fabrication, arrangement and fixation of the metasurface unit.

[0114] Optionally, this application embodiment uses the case where the incident wave is perpendicular to the metasurface, i.e., the incident angle of the wave is 0, as an example for illustration, because sinθ i =sin0=0, so according to formula (11) and formula (4), we can get:

[0115]

[0116] For example, the emission angle can be preset to 30°, and the center frequency of the incident wave can be obtained as 3.5 GHz. We can obtain Γ = 2λ, and We can obtain Γ = 172 mm. Since the metasurface units are all square with equal dimensions and the metasurface has 2 encoding bits, the side length of the metasurface unit can be calculated using formula (12).

[0117] Optionally, the length of the metasurface in the polarization direction parallel to the incident wave can be greater than or equal to the coding period, and the length of the metasurface in the polarization direction perpendicular to the incident wave can be greater than or equal to the wavelength of the incident wave. This allows the metasurface to effectively reflect the incident wave at a preset exit angle, ensuring the reflection effect of the metasurface.

[0118] It should be noted that the polarization direction of the incident wave is the direction of the electric field vector of the incident wave. When the incident wave is a horizontally polarized wave, its polarization direction is parallel to the ground, i.e., the horizontal direction; when the incident wave is a vertically polarized wave, its polarization direction is perpendicular to the ground, i.e., the direction perpendicular to the horizontal direction; when the incident wave is a ±45° dual-polarized wave, the angle between one polarization direction and the horizontal direction is 45°, and the angle between the two polarization directions is 90°.

[0119] Optionally, in the embodiments of this application, the codes corresponding to 3π / 4 of the four phases corresponding to the four metasurface units can be set as “00”, π / 4 as “01”, -π / 4 as “10”, and -3π / 4 as “11”.

[0120] For example, when the incident wave is horizontally polarized, the exit angle is 30°, and the center frequency of the incident wave is 3.5 GHz, as mentioned above, the coding period is 172 mm, the wavelength of the incident wave is 86 mm, and the side length of the metasurface unit is 43 mm. Therefore, the length of the metasurface in the polarization direction parallel to the incident wave, i.e., in the horizontal direction, can be at least 172 mm, which is one coding period. Since the wavelength of the incident wave is 86 mm and the side length of the metasurface unit is 43 mm, to ensure that the length of the metasurface in the polarization direction perpendicular to the incident wave is greater than or equal to the wavelength of the incident wave, the metasurface can contain at least two metasurface units in this direction, i.e., perpendicular to the horizontal direction. Figure 1 As shown, Figure 1This diagram illustrates the coding sequence corresponding to a first type of metasurface for a horizontally polarized wave, as provided in an embodiment of this application. The coding sequence corresponds one-to-one with each metasurface unit. In the coding sequence, "0" is equivalent to "00" and represents a phase of 3π / 4; "1" is equivalent to "01" and represents a phase of π / 4; "2" is equivalent to "10" and represents a phase of -π / 4; and "3" is equivalent to "11" and represents a phase of -3π / 4. When a horizontally polarized incident wave is incident on "0", the phase changes by 3π / 4; when it is incident on "1", the phase changes by π / 4; when it is incident on "2", the phase changes by -π / 4; and when it is incident on "3", the phase changes by -3π / 4. These emitted waves are then superimposed to obtain the complete emitted wave. Optionally, the coding sequence corresponding to the horizontally polarized wave in this embodiment can also be as follows: Figure 2 The encoded sequence shown, Figure 2 This is a schematic diagram of the coding sequence corresponding to a second type of metasurface for a horizontally polarized wave, provided in an embodiment of this application.

[0121] Optionally, this application does not limit the encoding sequence in the direction parallel to the polarization direction of the incident wave, as long as it contains multiple metasurface units whose corresponding phases are successively differed by a preset phase difference.

[0122] For example, when the incident wave is a vertically polarized wave with an exit angle of 30° and a center frequency of 3.5 GHz, as mentioned above, the coding period is 172 mm, the wavelength of the incident wave is 86 mm, and the side length of the metasurface unit is 43 mm. Therefore, the length of the metasurface in the polarization direction parallel to the incident wave (i.e., in the direction perpendicular to the horizontal direction) can be at least 172 mm, which is one coding period. Since the wavelength of the incident wave is 86 mm and the side length of the metasurface unit is 43 mm, to ensure that the length of the metasurface in the polarization direction perpendicular to the incident wave is greater than or equal to the wavelength of the incident wave, the metasurface can contain at least two metasurface units in the polarization direction perpendicular to the incident wave (i.e., in the horizontal direction), such as... Figure 3 As shown, Figure 3 This diagram illustrates the coding sequence corresponding to a first type of metasurface for a vertically polarized wave, as provided in an embodiment of this application. The coding sequence corresponds one-to-one with each metasurface unit. Optionally, the coding sequence corresponding to the vertically polarized wave in this embodiment can also be as follows: Figure 4 The encoded sequence shown, Figure 4 This is a schematic diagram of the encoding sequence corresponding to a second type of metasurface for a vertically polarized wave, provided in an embodiment of this application.

[0123] It should be noted that the number of metasurface units included in a certain direction mentioned in the embodiments of this application refers to the number of metasurface units in the same row distributed along that direction. For example, if at least two metasurface units can be included in the polarization direction perpendicular to the incident wave, it means that in the case of multiple rows of metasurface units arranged along the polarization direction perpendicular to the incident wave, each row includes at least two metasurface units. Following this logic, with... Figure 1 For example, Figure 1 The distribution shown can be described as including four metasurface units along the polarization direction parallel to the incident wave, or two metasurface units along the polarization direction perpendicular to the incident wave. Here, we take... Figure 1 The examples provided are for reference only. Figure 1 The distribution shown is intended to indicate the number of metasurface units and is not intended to limit the distribution of metasurface units in the technical solutions of this application.

[0124] Optionally, for single-polarized waves, i.e., horizontally polarized waves or vertically polarized waves, the phases of the metasurface units contained in the metasurface in the polarization direction perpendicular to the incident wave can be the same, such as... Figures 1 to 4 As shown. This allows the metasurface to reflect the incident wave at a preset angle along the polarization direction, making the reflection angle of the incident wave more accurate and ensuring the reflection effect of the metasurface.

[0125] Optionally, the angle between one side of the metasurface and the horizontal direction and 45° can be less than the angle error threshold, and the phases of multiple metasurface units distributed along any side of the metasurface can be sequentially differed by a preset phase difference.

[0126] Optionally, the angle error threshold can be 0.1°, 0.2° or 0.3°, etc. This application does not limit this, and the angle error threshold is described as 0.

[0127] For example, when the incident wave is a ±45° dual-polarized wave, the exit angle is 30°, and the center frequency of the incident wave is 3.5 GHz, as mentioned above, the coding period is 172 mm, the wavelength of the incident wave is 86 mm, and the side length of the metasurface unit is 43 mm. Therefore, the length of the metasurface in the polarization direction parallel to the incident wave (i.e., in the direction at a 45° angle to the horizontal) and in the direction perpendicular to the 45° angle to the horizontal can both be at least 172 mm, which is one coding period. Since the wavelength of the incident wave is 86 mm and the side length of the metasurface unit is 43 mm, for the length of the metasurface in the polarization direction perpendicular to the incident wave to be greater than or equal to the wavelength of the incident wave, the metasurface can contain at least two metasurface units in this direction. Because the length of the metasurface in the direction at a 45° angle to the horizontal and in the direction perpendicular to this 45° angle to the horizontal can be at least 172 mm, i.e., four metasurface units, this satisfies the requirement. Figure 5 As shown, Figure 5 This diagram illustrates the coding sequence corresponding to a first type of metasurface for a dual-polarized wave, as provided in an embodiment of this application. Optionally, the coding sequence corresponding to the dual-polarized wave in the embodiment can also be as follows: Figure 6 The coding sequences shown in Figures a and b are... Figure 6 This is a schematic diagram of the coding sequence corresponding to other metasurfaces for a dual-polarized wave, provided in an embodiment of this application.

[0128] By setting the angle between one side of the metasurface and the horizontal direction to be less than 45°, and by ensuring that the phases of multiple metasurface units distributed along any side of the metasurface are sequentially separated by a preset phase difference, it can be guaranteed that the metasurface after rotating 45° will reflect each polarized wave in the ±45° dual-polarized incident wave at a preset angle, thereby ensuring the reflection effect of the metasurface.

[0129] Optionally, the metasurface can reflect the incident wave by using multiple metasurface units with corresponding phases differing by a preset phase difference to alter the phase of the incident wave and emit them at their respective phases. These emitted waves are then superimposed to obtain a complete emitted wave, the emission angle of which meets the preset emission angle requirement. For example, the emission angle of the complete emitted wave can be approximately equal to or equal to the preset emission angle. Optionally, the method of superimposing the emitted waves follows the pattern product theorem.

[0130] Optionally, the number of rows of metasurface units parallel to the polarization direction of the incident wave can be an integer multiple of 2 to the power of N, and the integer can be greater than 1. Optionally, the integer can be 2, or it can be 3, 4, or 5, etc., and this application does not limit it in this regard. The reflection effect of the metasurface can be enhanced by superimposing multiple rows of metasurface units with continuous phase gradients.

[0131] Optionally, the integer can be 2. Choosing an integer of 2 can effectively enhance the reflection intensity of the metasurface. If the integer is greater than 2, it will not only increase the manufacturing cost but also increase the difficulty of fixing. Therefore, choosing an integer of 2 is more reasonable.

[0132] For example, such as Figure 7 As shown, Figure 7 This is a schematic diagram of the coding sequence corresponding to a third type of metasurface for a horizontally polarized wave, provided in an embodiment of this application. Figure 7 It can be seen that in the polarization direction parallel to the incident wave, i.e., the horizontal direction, there are 8 columns of metasurface units, meaning each row contains 8 metasurface units, and the phases of every 4 metasurface units in the same row differ by a preset phase difference. Figure 1 The corresponding encoded sequence is twice the length in the horizontal direction.

[0133] Optionally, the number of rows of metasurface units in the polarization direction perpendicular to the incident wave can be greater than 2, and the phases of any two adjacent metasurface units in the polarization direction perpendicular to the incident wave can be the same. The reflection effect of the metasurface can be enhanced by stacking multiple rows of metasurface units.

[0134] For example, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the coding sequence corresponding to a fourth type of metasurface for a horizontally polarized wave, provided in an embodiment of this application. Figure 8 It can be seen that in the polarization direction perpendicular to the incident wave, that is, in the direction perpendicular to the horizontal direction, each column contains 4 corresponding metasurface units with the same phase, compared to Figure 1 The corresponding encoding sequence has two additional rows in the vertical direction and the total number is greater than two, which meets the requirements.

[0135] It should be noted that the phase of any two adjacent metasurface units in the polarization direction perpendicular to the incident wave can be the same, but this only applies to single-polarized incident waves.

[0136] Optionally, the number of rows of metasurface units perpendicular to the polarization direction of the incident wave and the number of columns of metasurface units parallel to the polarization direction of the incident wave can be equal.

[0137] For example, the embodiments are as follows Figure 1 Based on the shown encoding sequence, set up 8×8 encoding sequences in the horizontal direction and perpendicular to the horizontal direction, such as... Figure 9 As shown, Figure 9 This is a schematic diagram of the coding sequence corresponding to a fifth type of metasurface for a horizontally polarized wave, provided in an embodiment of this application. Figure 9It can be seen that each column in the horizontal direction and each row perpendicular to the horizontal direction of the metasurface can contain 8 metasurface units, that is, the number of rows and columns are equal, and the phases of every 4 metasurface units in each row in the horizontal direction are successively different by a preset phase difference. Figure 10 This application provides a first type of reflection pattern corresponding to a metasurface. Figure 10 Metasurface units and Figure 9 The encoded sequences in the code correspond one-to-one, by Figure 10 It can be seen Figure 9 The coded sequence in the code corresponds to a metasurface that can reflect horizontally polarized waves incident perpendicularly to the metasurface. Figure 10 The darkest color in the middle is the emitted wave. Figure 11 This application provides a first reflection pattern of the xoz plane corresponding to a metasurface, wherein... Figure 11 The gain is greatest at point A, which is the direction of the outgoing wave. Figure 11 It can be seen that the vertically incident horizontally polarized incident wave, after being reflected by the metasurface, exits at an exit angle of 30°, which meets the design requirements.

[0138] Optionally, for horizontally polarized incident waves, the corresponding coding sequence can also be as follows: Figure 12 The three corresponding coding sequences shown in diagrams a, b, and c are... Figure 12 This is a schematic diagram of the coding sequence corresponding to other metasurfaces for a horizontally polarized wave, provided in an embodiment of this application.

[0139] Optionally, this application does not limit the encoding sequence of the metasurface, as long as it contains multiple metasurface units with corresponding phases that are sequentially differed by a preset phase difference in the same row in the polarization direction parallel to the incident wave.

[0140] For example, the embodiments are as follows Figure 5 Based on the shown coding sequence, an 8×8 coding sequence is set in the polarization direction parallel to the ±45° dual-polarized wave, as shown. Figure 13 As shown, Figure 13 This is a schematic diagram of the coding sequence corresponding to a second type of metasurface for a dual-polarized wave, provided in an embodiment of this application. Figure 13 It can be seen that each row (not limited to rows or columns) of the metasurface can contain 8 metasurface units in the polarization direction parallel to the incident wave, and the phases of every 4 metasurface units in the same row are successively different by a preset phase difference. Figure 14 This is a schematic diagram of a metasurface provided in an embodiment of this application. Figure 14 Metasurface units and Figure 13 The encoded sequences in the sequence correspond one-to-one, where Figure 14 In this diagram, A represents a metasurface unit, and B represents a metal patch. Figure 15This application provides a second reflection pattern corresponding to a metasurface, derived from... Figure 15 It can be seen Figure 13 The metasurface corresponding to the encoded sequence in the code can reflect perpendicularly incident ±45° dual-polarized waves. Figure 15 The darkest color in the middle is the emitted wave. Figure 16 This application provides a second reflection pattern for the xoz plane corresponding to a metasurface, wherein... Figure 16 The gain is greatest at point A, which is the direction of the outgoing wave. Figure 16 It can be seen that the metasurface reflects the +45° wave and -45° wave from the perpendicularly incident ±45° dual-polarized wave by 30° each. After superposition, the reflected wave is approximately equal to 45°, which meets the design requirements.

[0141] Optionally, for +45° dual-polarized waves, the corresponding coding sequence can also be as follows: Figure 17 The encoded sequence shown, Figure 17 This is a schematic diagram of the coding sequence corresponding to a third metasurface for a dual-polarized wave, provided in an embodiment of this application.

[0142] By setting the number of rows of metasurface units perpendicular to the polarization direction of the incident wave to be equal to the number of columns of metasurface units parallel to the polarization direction of the incident wave, the isotropic reflection of the incident wave by the metasurface can be guaranteed, facilitating the superposition of outgoing waves and making the reflection effect of the metasurface on the incident wave better.

[0143] Optionally, the first metasurface unit may include multiple metasurface subunits. The first metasurface unit can be any one of the multiple metasurface units, and the phase corresponding to each metasurface subunit and the first metasurface unit may be the same.

[0144] By setting multiple metasurface sub-units with the same phase as the corresponding metasurface unit, the mutual interference caused by adjacent metasurface units having different phases can be avoided, thus ensuring the reflection effect of the metasurface.

[0145] Optionally, each of the multiple metasurface sub-units can be square or nearly square in shape, such as a rectangle with minimal difference between adjacent sides. This application uses a square shape for the metasurface sub-unit as an example. By setting the shape of the metasurface sub-unit to a square, the design, fabrication, and fixation of the metasurface unit can be facilitated.

[0146] Optionally, the number of multiple metasurface sub-units can be 4, 9, or 16, etc. This application does not limit this, as long as the metasurface unit is square. Taking the number of multiple metasurface sub-units as an example, it will be explained.

[0147] For example, when the incident wave is a horizontally polarized wave, the exit angle is 45°, and the center frequency of the incident wave is 3.5 GHz, according to formula (13), we can obtain The encoding period can be obtained. The wavelength of the incident wave The coding period Γ = 121.62 mm can be calculated, and the side length of the metasurface unit can be calculated as 30.41 mm using formula (12). The number of metasurface units can be set to 8 in both the direction parallel to the polarization direction of the incident wave (horizontal direction) and the direction perpendicular to the polarization direction of the incident wave (vertical direction). Since each metasurface unit contains 4 metasurface subunits, and both the shape of the metasurface unit and the shape of the metasurface subunits are square, the metasurface unit contains 2 metasurface subunits in the same row in the direction parallel to the polarization direction of the incident wave and in the same column in the direction perpendicular to the polarization direction of the incident wave. Therefore, the side length of the metasurface subunit can be half the side length of the metasurface unit, which is 15.21 mm. Figure 18 As shown, Figure 18 This is a schematic diagram illustrating the coding sequence corresponding to a sixth metasurface for a horizontally polarized wave, as provided in an embodiment of this application. Figure 18 It can be seen that each metasurface unit contains four metasurface subunits with the same phase as the metasurface unit. Figure 19 This application provides a third type of reflection pattern corresponding to a metasurface. Figure 19 Metasurface units and metasurface subunits in Figure 18 The encoded sequences in the code correspond one-to-one, by Figure 19 It can be seen that a metasurface formed by multiple metasurface sub-units can effectively reflect vertically incident horizontally polarized waves. Figure 19 The darkest color in the middle is the emitted wave. Figure 20 This application provides a third reflection pattern for the xoz plane corresponding to a metasurface, wherein... Figure 20 The gain is greatest at point A, which is the direction of the outgoing wave. Figure 20 It can be seen that the incident wave, which is perpendicularly incident after being reflected by the metasurface, exits at an exit angle of 45°, which meets the requirements.

[0148] It should be noted that for ±45° dual-polarized waves, the corresponding metasurface can be obtained by rotating a metasurface composed of square metasurface units by 45°. Therefore, the metasurface subunits contained in the metasurface can also be squares rotated by 45°.

[0149] Optionally, the metasurface unit may include a metal patch, a dielectric substrate, and a metal ground plane. The metal patch and the metal ground plane may be respectively attached to opposite sides of the dielectric substrate plane, and the size of the metal patch may be smaller than the size of the metasurface unit. Figure 21 As shown, Figure 21 This is a schematic diagram of a metasurface unit provided in an embodiment of this application. In figure a, the black solid square is a metal patch, in figure b, the black solid square is a metal ground plane, and the white square plate in figures a and b is a dielectric substrate.

[0150] The subwavelength metasurface unit designed using metal patches, dielectric substrates, and metal ground planes has a simple structure, small size, and is easy to implement.

[0151] Optionally, the metal patch can be used to realize the phase corresponding to the metasurface unit. The manufacturing process of the metal patch can be copper-clad board, such as PCB (Printed Circuit Board) etching, plastic electroplating, or other processes. This application does not limit the specific process; PCB etching is used as an example. The material of the metal patch is also not limited. The PCB model can be Rogers RO4730 or others. The thickness of the metal patch can be the copper thickness of a double-sided copper-clad board. When the metasurface operates at Sub-6GHz, the copper thickness can be 1 oz. The metal patch can be etched on one side of the plane of the circuit board, and the other side of the circuit board can be completely copper-clad as a metal ground plane. The size of the metal ground plane can be the same as the size of the metasurface unit. In this embodiment, the dielectric substrate has a thickness of 1.6 mm and a dielectric constant of 3.0. Optionally, the thickness of the dielectric substrate can also be 1.5 mm, 1.7 mm, or other thicknesses. This application does not limit this. The dielectric constant of the dielectric substrate can also be 2.5, 2.65, or other thicknesses. This application does not limit this either.

[0152] Optionally, the shape of the metal patch can be mirror-symmetric and centrally symmetric, such as a square, regular hexagon, rectangle, circle, cross, or star shape, or other shapes, such as a triangle, parallelogram, or hollowed-out spiral shape. This application does not limit the shape; the embodiment uses a square metal patch as an example for illustration. Selecting a mirror-symmetric and centrally symmetric metal patch can make the metasurface unit insensitive to the polarization direction of the incident wave and ensure isotropy.

[0153] Optionally, when the metal patch is square, the ratio of the side length of the first metal patch to the preset initial side length can be a preset scaling factor, which can be phase-dependent with respect to the first metasurface unit; wherein, the first metal patch can be a metal patch of the first metasurface unit, and the preset initial side length can be greater than or equal to the subwavelength and can be less than the size of the first metasurface unit.

[0154] First, a preset initial side length can be set. The selection range of the preset initial side length can be smaller than the size of the first metasurface unit and greater than or equal to the subwavelength. In the embodiments of this application, smaller than the size of the first metasurface unit means smaller than the side length of the first metasurface unit. For example, if the side length of the first metasurface unit is known to be 43mm, then the preset initial side length can be less than 43mm. It should be noted that the subwavelength is a range. In this application, one-tenth of the incident wave wavelength can be selected as the subwavelength. For example, when the incident wave wavelength is 86mm, 8.6mm can be selected as the subwavelength. Therefore, the value range of the preset initial side length can be greater than or equal to 8.6mm and less than 43mm. 16mm can be selected as the preset initial side length L, or 10mm, 40mm, etc., as long as the value range of the preset initial side length is met. This application does not limit this. The example of a preset initial side length L of 16mm is used for illustration.

[0155] Once the preset initial side length is determined, the preset initial side length L can be multiplied by a scaling factor sc to determine the side length of the first metal patch, thus enabling it to achieve the corresponding phase, i.e., the phase corresponding to the first metasurface unit. It should be noted that when the phase corresponding to the first metasurface unit to be achieved is determined, the side length of the first metal patch that ultimately achieves the phase of the first metasurface unit is also determined. Optionally, when it is necessary to calculate the dimensions of metal patches for multiple metasurface units with a preset phase difference, each of the multiple metasurface units can be considered as the first metasurface unit, and then the calculation can be performed using the above steps.

[0156] In this embodiment, the relationship between the scaling variable sc and the phase corresponding to the first metasurface unit when the preset initial side length L is 16mm can be determined by looking up a table, see Table 1.

[0157] Table 1

[0158] Preset initial side length / mm proportional variable sc Phase corresponding to the first metasurface unit 16 1.38 3π / 4 16 1.438 π / 4 16 1.46 -π / 4 16 1.51 -3π / 4

[0159] The correspondence between the above Table 1 can be pre-calculated and stored in memory for later retrieval.

[0160] Figure 22This is a simulation diagram illustrating a first metasurface unit corresponding to four different phases under four different scaling variables, as provided in an embodiment of this application. Figure 22 Of the four curves, curve 1 shows the relationship between the center frequency and angle of the incident wave when the scaling factor sc is 1.38; curve 2 shows the relationship when the scaling factor sc is 1.438; curve 3 shows the relationship when the scaling factor sc is 1.46; and curve 4 shows the relationship when the scaling factor sc is 1.51. Figure 22 It can be seen that when the center frequency of the incident wave is 3.5 GHz, when the preset initial side length L = 16 mm is multiplied by the proportional variable sc = 1.38, that is, when the side length of the first metal patch is L1 = 22.08 mm, the corresponding angle is 131.47746°, approximately equal to 3π / 4; when the preset initial side length L = 16 mm is multiplied by the proportional variable sc = 1.438, that is, when the side length of the first metal patch is L2 = 23.008 mm, the corresponding angle is 43.412°. 0.15°, approximately equal to π / 4; when the preset initial side length L = 16mm is multiplied by the proportional variable sc = 1.46, that is, when the side length of the first metal patch is L3 = 23.36mm, the corresponding angle is -42.785638°, approximately equal to -π / 4; when the preset initial side length L = 16mm is multiplied by the proportional variable sc = 1.51, that is, when the side length of the first metal patch is L4 = 24.16mm, the corresponding angle is -134.27868°, approximately equal to -3π / 4.

[0161] Depend on Figure 22 The simulation diagram shows that the method of scaling the preset initial side length in this application can enable the first metal patch to realize the phase corresponding to the first metasurface unit, meet the design requirements of the metasurface unit, and is simple and fast, improving the efficiency and accuracy of metasurface design.

[0162] Optionally, the side length of the first metal patch can be determined directly using electromagnetic simulation software, employing methods such as FDTD (Finite Difference Time Domain) or FEM (Finite Element Method). Alternatively, the side length can be determined through an equivalent circuit model. Specifically, the first metal patch can be modeled as a series circuit with an inductor and a capacitor. When the size of the first metal patch changes, the inductance and capacitance values ​​in the equivalent circuit also change, resulting in a change in the phase realized by the corresponding first metasurface unit. Therefore, the inductance and capacitance values ​​in the equivalent circuit can be determined using the known phase of the first metasurface unit, thus determining the side length of the first metal patch. The side length of the first metal patch is positively correlated with the inductance and capacitance values.

[0163] Optionally, other methods can be used to make the metal patch realize the phase corresponding to the metasurface unit, such as rotation. This application does not limit this, as long as the metal patch can realize the phase corresponding to the metasurface unit.

[0164] Optionally, the metal patches contained in the multiple metasurface units in the metasurface can have the same or different shapes, as long as the corresponding phase can be achieved. This application does not limit this. The embodiment is illustrated by taking the example that all the metal patches are square.

[0165] As discussed above, the dimensions of a metasurface unit can be calculated by pre-setting the emission angle. Therefore, multiple metasurfaces can be pre-set, each with a different preset emission angle. In practical applications, the appropriate metasurface can be selected based on the required emission angle. This approach allows for direct selection of the metasurface corresponding to the desired emission angle in emergency situations, saving time in metasurface design and offering convenience and efficiency.

[0166] Optionally, embodiments of this application also provide a communication device that may include multiple cascaded metasurfaces as described above. By setting multiple cascaded metasurfaces, the reflection path of the incident wave can be changed, allowing the incident wave to be transmitted to the desired location.

[0167] Optionally, the number of multiple metasurfaces can be 1, 2, 3 or 4, etc. This application does not limit this, and can be set according to the actual situation.

[0168] Optionally, multiple metasurfaces can be used to progressively adjust the reflection path of the incident wave. The shape of the reflection path can be at least one of U-shape, N-shape, L-shape, W-shape, M-shape, V-shape, and Z-shape, or other shapes. This application does not limit this; taking the reflection path as an example... Figure 23The reflection path shown is used as an example for illustration.

[0169] Figure 23 This is a schematic diagram of a reflection path provided in an embodiment of this application, wherein, Figure 23 Point A in the diagram is the base station, used to transmit incident waves. Metasurfaces, designated as metasurface 1, metasurface 2, and metasurface 3, are arranged at the three corners. Point B is the user terminal, used to receive the incident waves after they have been reflected sequentially by the three metasurfaces. The three cascaded metasurfaces reflect the incident waves emitted by the base station step by step, thereby adjusting the reflection path of the incident waves and ultimately transmitting them to the user terminal.

[0170] Optionally, before the incident wave is reflected by multiple cascaded metasurfaces, the incident and exit angles can be assigned to each metasurface according to the reflection path. Figure 23 Taking the reflection path as an example, the propagation direction of the incident wave, which is perpendicular to the horizontal plane, needs to be changed to a horizontal direction, and it needs to pass through three perpendicular corners. The incident angle and exit angle of metasurface 1 can be assigned to 45° and 45° respectively; the incident angle and exit angle of metasurface 2 to 30° and 60° respectively; and the incident angle and exit angle of metasurface 3 to 30° and 60° respectively. Metasurfaces 1, 2, and 3 reflect the incident wave sequentially, ultimately transmitting the incident wave to the user terminal.

[0171] Optionally, each metasurface in the communication system can be implemented by determining the size of the metasurface unit based on the incident and exit angles assigned to it, and then arranging the metasurface units to form the required metasurface. For specific implementation methods, please refer to the above. Alternatively, multiple metasurfaces with different or the same incident and / or reflection angles can be pre-set, and selected according to the actual situation.

[0172] Figure 24 This is a schematic diagram of another reflection path provided in an embodiment of this application. In diagrams a, b, and c, the triangles represent the incident points, the squares represent the exit points, the circles at the corners represent metasurfaces, and the straight lines with arrows represent the reflection paths. Figure 24 It can be seen that by using cascaded metasurfaces, incident waves can be reflected step by step in tortuous environments, ultimately allowing the incident waves to be transmitted to the desired location. Figure 24 The point of departure in the middle.

[0173] By placing multiple cascaded metasurfaces at the corners of different reflection paths, the reflection path of the incident wave emitted by the base station can be adjusted step by step, ultimately enabling it to be transmitted to the user terminal. This enhances network coverage and meets the needs for enhanced wireless network coverage in complex environments, such as outdoor coverage obstructed by buildings, indoor winding and narrow passages, tunnels, or mines.

[0174] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0175] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0176] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A metasurface, characterized in that, The metasurface includes a plurality of metasurface units, the number of which is at least 2 to the power of N. The phases of each metasurface unit are sequentially differed by a preset phase difference. The difference between the preset phase difference and a first ratio is less than a phase error threshold. The first ratio is 2π to 2 to the power of N, where N is the encoding bit of the metasurface. The size of the first metasurface unit is positively correlated with the ratio of the coding period to the power of 2, wherein the first metasurface unit is any one of the plurality of metasurface units, the coding period is positively correlated with the ratio of the phase gradient to 2π, the phase gradient is positively correlated with the product of a first difference and a second ratio, the first difference is positively correlated with the difference between the sine of the exit angle and the sine of the incident angle, and the second ratio is positively correlated with the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave.

2. The metasurface according to claim 1, characterized in that, The size of the first metasurface unit is the ratio of the coding period to the power of 2, the coding period is the ratio of 2π to the phase gradient, the phase gradient is the product of a first difference and a second ratio, the first difference is the difference between the sine of the exit angle and the sine of the incident angle, and the second ratio is the ratio of the product of 2π and the refractive index of the incident interface to the wavelength of the incident wave.

3. The metasurface according to claim 1 or 2, characterized in that, When the metasurface unit is square, the side length of the metasurface unit is the ratio of the encoding period to the power of 2.

4. The metasurface according to claim 3, characterized in that, The length of the metasurface in the polarization direction parallel to the incident wave is greater than or equal to the coding period, and the length of the metasurface in the polarization direction perpendicular to the incident wave is greater than or equal to the wavelength of the incident wave.

5. The metasurface according to claim 4, characterized in that, The number of metasurface units parallel to the polarization direction of the incident wave is an integer multiple of 2 raised to the power of N, where the integer is greater than 1.

6. The metasurface according to claim 5, characterized in that, The integer is 2.

7. The metasurface according to claim 3, characterized in that, The first metasurface unit includes multiple metasurface subunits, and the first metasurface unit is any one of the multiple metasurface units. Each metasurface subunit has the same phase as the first metasurface unit.

8. The metasurface according to claim 7, characterized in that, Each of the plurality of metasurface subunits is square in shape.

9. The metasurface according to claim 4, characterized in that, The number of metasurface units perpendicular to the polarization direction of the incident wave is greater than 2, and any two adjacent metasurface units perpendicular to the polarization direction of the incident wave have the same phase.

10. The metasurface according to claim 9, characterized in that, The number of metasurface units perpendicular to the polarization direction of the incident wave is equal to the number of metasurface units parallel to the polarization direction of the incident wave.

11. The metasurface according to claim 10, characterized in that, The angle between one side of the metasurface and the horizontal direction is less than 45°, and the phases of the multiple metasurface units distributed along any side of the metasurface are sequentially differed by a preset phase difference.

12. The metasurface according to claim 1, characterized in that, The metasurface unit includes a metal patch, a dielectric substrate, and a metal ground plane. The metal patch and the metal ground plane are respectively attached to both sides of the dielectric substrate plane. The size of the metal patch is smaller than the size of the metasurface unit.

13. The metasurface according to claim 12, characterized in that, The shape of the metal patch is both mirror-symmetric and centrally symmetric.

14. The metasurface according to claim 12 or 13, characterized in that, The metal patch is square, and the ratio of the side length of the first metal patch to the preset initial side length is a preset scaling factor. The preset scaling factor is phase-dependent with respect to the first metasurface unit. Wherein, the first metal patch is the metal patch of the first metasurface unit, and the preset initial side length is greater than or equal to the subwavelength and smaller than the size of the first metasurface unit.

15. A communication device, characterized in that, The communication device includes cascaded metasurfaces as described in any one of claims 1 to 14.

16. The communication device according to claim 15, characterized in that, The plurality of metasurfaces are used to progressively adjust the reflection path of the incident wave, wherein the shape of the reflection path is at least one of U-shape, N-shape, L-shape, W-shape, M-shape, V-shape, and Z-shape.

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