Metasurface unit and metasurface

Abstract

The invention provides a metasurface unit and a metasurface. The metasurface unit comprises a metal ground layer; the liquid crystal layer is arranged on the metal ground layer; the at least one metal patch is arranged on one side, far away from the metal ground layer, of the liquid crystal layer, and the at least one metal patch is connected to a power supply through a bias line; the at least one metal patch is rectangular, and the extension directions of the long sides of the at least one metal patch are the same. The metasurface unit provided by the invention has a single polarization direction, prevents cross polarization, ensures the reflection quality of the metasurface, and avoids occupying cross polarization resources. The metasurface unit provided by the invention has multi-frequency working capability. Meanwhile, the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit are continuously adjustable, the flexibility of adjustment of the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit is improved, and the range of the working frequency band of the metasurface unit is large.

Description

Metasurface unit and metasurface Technical Field

[0001] The present disclosure relates to the field of metasurface technology, and in particular to a metasurface unit and a metasurface. Background Art

[0002] Metasurfaces are a new technology that has emerged in recent years. They are composed of periodic or aperiodic arrangements of metasurface units. As a two-dimensional form of metamaterial, metasurfaces are playing an increasingly important role in many scientific fields, including electromagnetism, optics, acoustics, and thermodynamics. Liquid crystal is a common tunable material in the millimeter-wave frequency band and has relatively low dielectric loss and optical transparency. Therefore, liquid crystal materials are often added to metasurfaces to achieve phase and / or amplitude adjustment of the metasurface.

[0003] In related technologies, the metasurface unit of a metasurface based on liquid crystal regulation adopts an anisotropic structure, which has two polarization directions. The two polarization directions operate in one frequency band respectively. By adjusting the dielectric constant of the liquid crystal material in the metasurface unit, the phase response of the metasurface unit in different polarization directions is changed, thereby constructing a metasurface with dual-frequency working capability.

[0004] However, in related technologies, since the metasurface unit has two different polarization directions and the two polarization directions operate in one frequency band respectively, cross-polarization may occur, which may affect the reflection quality of the metasurface and occupy cross-polarization resources.

[0005] Summary of the Invention

[0006] The metasurface unit and metasurface proposed in the present disclosure are a millimeter-wave single-polarization dual-frequency reflective metasurface based on liquid crystal adjustment, which can avoid cross-polarization, ensure the reflection quality of the metasurface, and will not occupy cross-polarization resources.

[0007] In a first aspect, an embodiment of the present disclosure provides a metasurface unit, comprising:

[0008] metallic formations;

[0009] a liquid crystal layer, the liquid crystal layer being disposed on the metal layer;

[0010] At least one metal patch is arranged on a side of the liquid crystal layer away from the metal ground layer, and the at least one metal patch is connected to a power supply through a bias line; the at least one metal patch is rectangular, and the long sides of the at least one metal patch extend in the same direction.

[0011] In the metasurface unit provided in the present disclosure, by making the extension direction of the long sides of at least one rectangular metal patch the same, the metasurface unit has a single polarization direction, which prevents cross-polarization, ensures the reflection quality of the metasurface, and avoids occupying cross-polarization resources. In addition, in the present disclosure, by making the size of at least one rectangular metal patch different, the metasurface unit has multi-frequency working capability. At the same time, in the present disclosure, by using a liquid crystal layer as an adjustable material to form a metasurface unit, the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit can be continuously adjusted, thereby improving the flexibility of adjusting the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit. In addition, since the insertion loss of liquid crystal is small and the practical applicability is high, when liquid crystal is used as an adjustable material, the operating frequency band of the metasurface unit can reach millimeter waves or even terahertz bands, thereby expanding the operating frequency band of the metasurface unit.

[0012] In a second aspect, an embodiment of the present disclosure provides a metasurface, comprising:

[0013] At least one metasurface unit as described in the first aspect above. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0015] FIG1 is a schematic top view of a metasurface unit provided by an embodiment of the present disclosure;

[0016] FIG2 is a schematic side view of a metasurface unit provided by an embodiment of the present disclosure;

[0017] FIG3 is a schematic diagram showing changes in the reflection and / or scattering amplitude and the reflection and / or scattering phase of a metasurface unit under incident beams of different frequencies and when the dielectric constant of the liquid crystal layer 5 of the metasurface unit is different, provided by an embodiment of the present disclosure;

[0018] Figure 4 shows the two-dimensional far-field patterns of the metasurface at different phase periods when the incident beam frequency is 23.1 GHz;

[0019] Figure 5 shows the two-dimensional far-field pattern of the metasurface at different phase periods when the incident beam frequency is 29.8 GHz. DETAILED DESCRIPTION

[0020] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible implementations consistent with the present disclosure. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0021] The terms used in the embodiments of the present disclosure are for the purpose of describing specific embodiments only and are not intended to limit the embodiments of the present disclosure. The singular forms "a," "an," and "the" used in the embodiments of the present disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0022] It should be understood that although the terms first, second, third, etc. may be used to describe various information in the embodiments of the present disclosure, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the embodiments of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0023] The embodiments of the present disclosure are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be understood as limiting the present disclosure.

[0024] To facilitate understanding, the terms involved in this application are first introduced.

[0025] 1. Metasurface

[0026] A metasurface is an artificial layered material with a thickness less than the wavelength. Metasurfaces can flexibly and effectively adjust the polarization, amplitude, phase, polarization mode, and propagation mode of electromagnetic waves. Metasurfaces can be considered the two-dimensional counterpart of metamaterials.

[0027] The metasurface unit and metasurface provided by the embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0028] FIG1 is a schematic top view of a metasurface unit provided in an embodiment of the present disclosure, and FIG2 is a schematic side view of a metasurface unit provided in an embodiment of the present disclosure. As shown in FIG1 and FIG2 , the metasurface unit may include:

[0029] a metal ground layer 6 (i.e., the metal ground 6 shown in FIG. 1 and FIG. 2 );

[0030] a liquid crystal layer 5 (i.e., the liquid crystal material 5 shown in FIG. 1 and FIG. 2 ), which is disposed on the metal layer 6;

[0031] At least one metal patch (Figures 1 and 2 are illustrated by taking metal patch 2 and metal patch 3 as an example), the at least one metal patch is arranged on a side of the liquid crystal layer 5 away from the metal ground layer 6, and the at least one metal patch is connected to the power supply through a bias line 4; the at least one metal patch is rectangular, and the long sides of the at least one metal patch extend in the same direction. As shown in Figures 1 and 2, the long sides of the metal patch 2 and the metal patch 3 extend in the Y direction in the figure.

[0032] In one embodiment of the present disclosure, the metal layer 6 and the at least one metal patch can be used as a reflector and / or scatterer of the metasurface unit to reflect and / or scatter an incident beam.

[0033] It should be noted that when the metal patch is rectangular, the polarization direction of the reflected and / or scattered beam is related to the extension direction of the long side of the metal patch. Based on this, in one embodiment of the present disclosure, by making the extension direction of the long side of at least one metal patch the same, the polarization direction of the metasurface unit is made a single polarization direction, which can avoid cross-polarization, ensure the reflection quality of the metasurface, and avoid occupying cross-polarization resources.

[0034] And, in one embodiment of the present disclosure, for the metal patch, if its size is different, its operating frequency band when reflecting and / or scattering the incident beam is also different. Among them, the operating frequency band of the metal patch can be understood as: the frequency band of the beam that the metal patch can reflect and / or scatter. For example, if the operating frequency band of the metal patch is 10 GHz (gigahertz) to 20 GHz, then the beam that the metal patch can reflect and / or scatter is: a beam with a frequency between 10 GHz and 20 GHz. In other words, the metal patch is mainly used to: reflect and / or scatter the incident beam whose frequency belongs to the operating frequency band corresponding to the metal patch.

[0035] Based on this, in one embodiment of the present disclosure, by making the different metal patches of the metasurface unit have different sizes, the metasurface unit is enabled to have multi-band operating capabilities (i.e., multi-band reflection and / or scattering capabilities). The different sizes of the different metal patches can indicate different lengths and / or different widths of the different metal patches, which correspondingly means that the different metal patches have different areas.

[0036] In addition, the present disclosure mainly uses the example of a metasurface unit including two metal patches, and the two metal patches can be respectively: a first metal patch (i.e., metal patch 2 in Figures 1 and 2) and a second metal patch (i.e., metal patch 3 in Figures 1 and 2), wherein the first metal patch and the second metal patch are arranged side by side, that is, the extension direction of the long side of the first metal patch is the same as the extension direction of the long side of the second metal patch, and the size of the first metal patch is different from the size of the second metal patch, thereby constructing a single-polarization dual-frequency reflective metasurface unit.

[0037] Furthermore, in one embodiment of the present disclosure, the metasurface unit may further include:

[0038] a first substrate, the first substrate being arranged on a side of the metal layer 6 away from the liquid crystal layer 5;

[0039] A second substrate is provided on a side of the at least one metal patch away from the liquid crystal layer 5 .

[0040] The first and second substrates can provide attachment support for other layers, thereby restraining the flow of liquid crystals and also serve to encapsulate the liquid crystal material. Furthermore, both the first and second substrates can be made of glass. Referring to Figure 2 , the first substrate can be the lower layer of glass 7, and the second substrate can be the upper layer of glass 1. The first and second substrates can be made of BF33. Of course, other substrate materials are also possible.

[0041] Furthermore, in one embodiment of the present disclosure, the at least one metal patch may be made of the same metal material, such as copper or silver.

[0042] The above content is an introduction to the structure of the metasurface unit in this disclosure. As can be seen from the above content, the metasurface unit in this disclosure is mainly a single-polarization multi-frequency metasurface unit. However, the metasurface unit in this disclosure also has continuous adjustability, which is described below.

[0043] In one embodiment of the present disclosure, the liquid crystal layer in the metasurface unit can be used as an adjustable material to adjust the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit, and the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit adjusted based on the liquid crystal layer in the present disclosure are continuously adjustable.

[0044] Specifically, in one embodiment of the present disclosure, the metal ground layer 6 can also serve as the negative electrode of the DC bias, and at least one metal patch can serve as the positive electrode of the DC bias. Based on this, by adjusting the voltage of the power supply connected to the bias line 4, the voltage output to the metal patch can be changed, thereby changing the voltage drop across the liquid crystal layer 5, and further changing the dielectric constant of the liquid crystal layer 5. In addition, in one embodiment of the present disclosure, when the dielectric constant of the liquid crystal layer 5 is different, the reflection and / or scattering amplitude and reflection and / or scattering phase of the metal patch and the metal ground when reflecting and / or scattering the incident beam will also be different, thereby achieving the adjustability of the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit.

[0045] Furthermore, it should be noted that in the present disclosure, when the dielectric constant of the liquid crystal layer 5 is adjusted by adjusting the voltage of the power supply, the dielectric constant of the liquid crystal layer 5 is continuously adjustable. Continuously adjustable can be understood as: the dielectric constant of the liquid crystal layer 5 can be continuously and non-discretely adjusted from a certain value to another value. Based on this, since the dielectric constant of the liquid crystal layer 5 is continuously adjustable, the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit can also be continuously adjustable.

[0046] It can be seen from the above that in the present disclosure, the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit for the incident beam are related to the dielectric constant of the liquid crystal layer; the dielectric constant of the liquid crystal layer is related to the voltage of the power supply. Therefore, by adjusting the voltage of the power supply to change the dielectric constant of the liquid crystal layer of the metasurface unit, the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit can be continuously adjusted. Among them, Figure 3 is a schematic diagram of the changes in the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit when the dielectric constant of the liquid crystal layer 5 of the metasurface unit is different under incident beams of different frequencies provided by an embodiment of the present disclosure. Figure 3 is illustrated by taking the dielectric constants ε of the liquid crystal layer 5 of the metasurface unit as ε=2.4, ε=2.9, ε=3.4, and ε=3.9 as examples.

[0047] Among them, the four lines located at the top in Figure 3 are schematic diagrams of the change in the reflection amplitude of the metasurface unit when the dielectric constant ε of the liquid crystal layer 5 of the metasurface unit is ε=2.4, ε=2.9, ε=3.4, and ε=3.9, when the frequency of the incident beam is different. Referring to Figure 3, it can be seen that when the dielectric constant ε of the liquid crystal layer 5 of the metasurface unit is ε=2.4, ε=2.9, ε=3.4, and ε=3.9, when the frequency of the incident beam is 23.1GHz and 29.8GHz, the reflection amplitude of the metasurface unit is less than -2dB, then its reflection loss is low and the reflection accuracy is high.

[0048] In addition, the four lines at the bottom in Figure 3 are schematic diagrams of the change in the reflection phase of the metasurface unit when the dielectric constant ε of the liquid crystal layer 5 of the metasurface unit is ε=2.4, ε=2.9, ε=3.4, and ε=3.9, respectively, when the frequency of the incident beam is different. Referring to Figure 3, it can be seen that when the frequency of the incident beam is 23.1GHz and 29.8GHz, as the dielectric constant of the liquid crystal layer 5 changes, the reflection phase of the metasurface unit changes over 270°.

[0049] From the above, it can be seen that when a liquid crystal layer is used as an adjustable material to form a metasurface unit, the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit can be continuously adjusted, thereby increasing the flexibility of adjusting the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit. At the same time, due to the low insertion loss of liquid crystal and its high practical applicability, when liquid crystal is used as an adjustable material, the operating frequency band of the metasurface unit can reach the millimeter wave or even terahertz band, thus expanding the operating frequency band of the metasurface unit.

[0050] Based on the above, it can be seen that the metasurface unit disclosed in this disclosure has the following characteristics:

[0051] Continuously adjustable, which can improve the flexibility of adjustment;

[0052] It has a single polarization direction, which can prevent cross-polarization, ensure the reflection quality of the metasurface, and avoid occupying cross-polarization resources;

[0053] Capable of multi-frequency operation;

[0054] The operating frequency band can reach millimeter wave or even terahertz band, expanding the operating frequency band of the metasurface unit.

[0055] Therefore, the present disclosure provides a millimeter-wave single-polarization multi-frequency (such as dual-frequency) reflective metasurface unit based on liquid crystal regulation.

[0056] In summary, the metasurface unit provided by the present disclosure includes a metal layer; a liquid crystal layer disposed on the metal layer; at least one metal patch disposed on a side of the liquid crystal layer away from the metal layer, the at least one metal patch being connected to a power supply via a bias line; the at least one metal patch being rectangular, and the long sides of the at least one metal patch extending in the same direction. The metasurface unit provided by the present disclosure is configured such that the long sides of the at least one rectangular metal patch extend in the same direction, thereby providing the metasurface unit with a single polarization direction, preventing cross-polarization, ensuring the reflection quality of the metasurface, and avoiding occupying cross-polarization resources. Furthermore, the metasurface unit is configured such that the size of the at least one rectangular metal patch is different, thereby providing the metasurface unit with multi-frequency operation capability. Furthermore, the metasurface unit is configured such that the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit are continuously adjustable by utilizing the liquid crystal layer as an adjustable material, thereby improving the flexibility of adjusting the reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit. In addition, since liquid crystal has a small insertion loss and high practical applicability, when liquid crystal is used as an adjustable material, the operating frequency band of the metasurface unit can reach the millimeter wave or even the terahertz band, which expands the operating frequency band of the metasurface unit.

[0057] In addition, it should be noted that the thicknesses of the liquid crystal layer, metal layer, metal patch, first substrate, and second substrate in the above-mentioned metasurface unit can be adaptively changed, wherein when the thicknesses of the liquid crystal layer, metal layer, metal patch, first substrate, and second substrate change, the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit will also change accordingly.

[0058] Furthermore, the present disclosure also provides a metasurface, comprising: at least one metasurface unit as shown in Figures 1 and 2 above. In one embodiment of the present disclosure, the metasurface may be formed by periodically or non-periodically arranging metasurface units. For example, in one embodiment of the present disclosure, the metasurface may be formed by periodically arranging metasurface units, for example, the metasurface may be arranged in a matrix. In particular, the metasurface may include m×n metasurface units, where m represents rows and n represents columns, and both m and n are positive integers. However, it should be understood that other possible arrangements are also within the scope of protection of the present disclosure, and the present disclosure does not limit this.

[0059] And, it should be noted that, in one embodiment of the present disclosure, the beam reflected and / or projected by the metasurface is formed by the joint action of all or part of the metasurface units of the metasurface. The joint action of all or part of the metasurface units can be understood as the common reflection and / or scattering of the incident beam by all or part of the metasurface units. Based on this, it can be determined that the reflection and / or scattering beam deflection angle of the metasurface is mainly related to the reflection and / or scattering amplitude and reflection and / or scattering phase of all or part of the metasurface units. In other words, the reflection and / or scattering beam deflection angle of the metasurface is mainly related to the phase period of the metasurface. The phase period of the metasurface can be understood as: by adjusting the dielectric constant of the liquid crystal layer in the metasurface unit in the metasurface to take different values, the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit are periodically changed.

[0060] For example, the above phase period is introduced by taking an example, assuming that the metasurface includes 1×4 metasurface units, namely metasurface unit #a, metasurface unit #b, metasurface unit #c, and metasurface unit #d. When the dielectric constants of the metasurface unit #a, metasurface unit #b, metasurface unit #c and metasurface unit #d are adjusted to be the first value, the second value, the first value and the second value respectively, then at this time all the metasurface units take the same dielectric constant periodically with two metasurface units as the granularity, that is, the reflection and / or scattering amplitude and the reflection and / or scattering phase with two metasurface units as the granularity are periodically changed; therefore, the phase period of the metasurface at this time is 2; similarly, the dielectric constants of the metasurface unit #a, metasurface unit #b, metasurface unit #c and metasurface unit #d are all the first value, then the phase period of the metasurface at this time is 1; the dielectric constants of the metasurface unit #a, metasurface unit #b, metasurface unit #c and metasurface unit #d are adjusted to be the first value, the second value, the third value and the fourth value respectively, then the phase period of the metasurface at this time is 4.

[0061] From the above content, it can be seen that the phase period of the metasurface will affect the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit, and thus affect the reflection and / or scattering beam deflection angle of the metasurface (that is, the reflection and / or scattering beam deflection angle of the metasurface is related to the phase period of the metasurface), and the phase period of the metasurface is related to the dielectric constant; based on this, by adjusting the dielectric constant of the liquid crystal layer in different metasurface units of the metasurface, the phase period of the metasurface can be adjusted, and then the reflection and / or scattering beam deflection angle of the metasurface can be adjusted to achieve different beam adjustment functions. And, it should be noted that, under the premise that the dielectric constant of the liquid crystal layer is continuously adjustable, the reflection and / or scattering beam deflection angle of the metasurface should also be continuously adjustable.

[0062] Furthermore, it should be noted that in one embodiment of the present disclosure, when adjusting the dielectric constant of the liquid crystal layer in the metasurface unit, the adjustment can be performed with the same column or the same row granularity, such as by adjusting the dielectric constant of the liquid crystal layer in the metasurface units in the same column to be the same, and adjusting the dielectric constant of the liquid crystal layer in the metasurface units in different columns to be different or the same, so as to adjust the phase period of the metasurface; or, by adjusting the dielectric constant of the liquid crystal layer in the metasurface units in the same row to be the same, and adjusting the dielectric constant of the liquid crystal layer in the metasurface units in different rows to be different or the same, so as to adjust the phase period of the metasurface, thereby reducing the complexity of the feeding network.

[0063] Based on this, the following introduces the two-dimensional far-field radiation patterns of the metasurface under different phase periods, taking the incident beam frequencies of low frequency 23.1 GHz and high frequency 29.8 GHz as examples.

[0064] For example, assume that the metasurface includes m×16 metasurface units, where the dielectric constant of the liquid crystal layer of each metasurface unit is adjusted on a column-by-column basis. That is, the dielectric constant of the liquid crystal layer of metasurface units in the same column is the same. Based on this, Figure 4 shows the two-dimensional far-field patterns of the metasurface at different phase periods when the incident beam frequency is 23.1 GHz; Figure 5 shows the two-dimensional far-field patterns of the metasurface at different phase periods when the incident beam frequency is 29.8 GHz.

[0065] Among them, #1 in Figures 4 and 5 indicates that the phase period of the metasurface unit is arranged according to 1111111111111111. The "arranged according to 111111111111111" can be understood as: the dielectric constant ε of the liquid crystal layer of the metasurface units in the first to sixteenth columns of the metasurface is the same, ε = 2.4, so the phase period is 1. Among them, the metasurface unit with a dielectric constant ε = 2.4 can be named metasurface unit 1 in this disclosure.

[0066] #2 in Figure 4 indicates that the phase period of the metasurface unit is: arranged according to 1234123412341234. The "arranged according to 1234123412341234" can be understood as: the dielectric constants of the liquid crystal layers of the metasurface units in the first, fifth, ninth and thirteenth columns of the metasurface are all the same, ε=2.4; the dielectric constants of the liquid crystal layers of the metasurface units in the second, sixth, tenth and fourteenth columns of the metasurface are all the same, ε=2.93; the dielectric constants of the liquid crystal layers of the metasurface units in the third, seventh, eleventh and fifteenth columns of the metasurface are all the same, ε=3.18; the dielectric constants of the liquid crystal layers of the metasurface units in the fourth, eighth, twelfth and sixteenth columns of the metasurface are all the same, ε=3.8; thus, the phase period is four. Among them, in the present disclosure, the metasurface unit with a dielectric constant ε = 2.4 can be named metasurface unit 1, the metasurface unit with a dielectric constant ε = 2.93 can be named metasurface unit 2, the metasurface unit with a dielectric constant ε = 3.18 can be named metasurface unit 3, and the metasurface unit with a dielectric constant ε = 3.8 can be named metasurface unit 4.

[0067] #2 in Figure 5 indicates that the phase period of the metasurface unit is: arranged according to 1234123412341234. The "arranged according to 1234123412341234" can be understood as: the dielectric constants of the liquid crystal layers of the metasurface units in the first, fifth, ninth and thirteenth columns of the metasurface are all the same, ε=2.4; the dielectric constants of the liquid crystal layers of the metasurface units in the second, sixth, tenth and fourteenth columns of the metasurface are all the same, ε=2.72; the dielectric constants of the liquid crystal layers of the metasurface units in the third, seventh, eleventh and fifteenth columns of the metasurface are all the same, ε=2.88; the dielectric constants of the liquid crystal layers of the metasurface units in the fourth, eighth, twelfth and sixteenth columns of the metasurface are all the same, ε=3.5; and the phase period is also four. Among them, in the present disclosure, the metasurface unit with a dielectric constant ε = 2.4 can be named metasurface unit 1, the metasurface unit with a dielectric constant ε = 2.88 can be named metasurface unit 2, the metasurface unit with a dielectric constant ε = 3.18 can be named metasurface unit 3, and the metasurface unit with a dielectric constant ε = 3.5 can be named metasurface unit 4.

[0068] In addition, #3 in Figures 4 and 5 indicates that the phase period of the metasurface unit is arranged according to 1122334411223344, and the phase period is eight. #4 indicates that the phase period of the metasurface unit is arranged according to 1112223334441112, and the phase period is twelve. #5 indicates that the phase period of the metasurface unit is arranged according to 4321432143214321, and the phase period is four. #6 indicates that the phase period of the metasurface unit is arranged according to 4433221144332211, and the phase period is eight. #7 indicates that the phase period of the metasurface unit is arranged according to 2111444333222111, and the phase period is twelve. Among them, the principles of the above-mentioned "arrange according to 1122334411223344", "arrange according to 1112223334441112", "arrange according to 4321432143214321", "arrange according to 4433221144332211", and "arrange according to 2111444333222111" are similar to the aforementioned "arrange according to 1111111111111111" and "arrange according to 1234123412341234", and will not be repeated here.

[0069] Also, “Theta” in FIG4 and FIG5 represents the deflection angle of the reflected beam of the metasurface; and “Normalized Amplitude” in FIG4 and FIG5 represents the normalized amplitude of the reflected beam of the metasurface.

[0070] As shown in Figure 4, at the low frequency of 23.1 GHz, the reflected beam deflection angle of the metasurface with phase period #2 is 14°, and the reflected beam deflection angle of the metasurface with phase period #5 is -14°. The reflected beam deflection angle of the metasurface with phase period #3 is 23°, and the reflected beam deflection angle of the metasurface with phase period #6 is -23°. Furthermore, referring to Figures 4 and 5, it can be seen that at the low frequency of 23.1 GHz, the beam scans to ±14°, ±23°, and ±50°, respectively, and at the high frequency of 29.8 GHz, the beam scans to ±11.6°, ±17°, and ±36.5°, respectively. At both frequencies, the metasurface achieves beam scanning.

[0071] In summary, the present disclosure provides a reflective metasurface with a simple design, low profile, dual-frequency working capability, and applicable to the millimeter wave frequency band. The present disclosure constructs a reflective metasurface based on liquid crystal adjustment. In the past, metasurfaces loaded with diodes could only operate in the lower microwave band, but when liquid crystal is used as an adjustable material, the working frequency band of the metasurface can reach the millimeter wave or even the terahertz band. The present disclosure expands the working frequency band of the metasurface. The present disclosure constructs a reflective metasurface based on a double-patch structure, in which two patches of different sizes respectively operate in one working frequency band, constructing a metasurface with dual-frequency working capability. The reflective metasurface based on liquid crystal adjustment disclosed in the present disclosure has the characteristic of continuous adjustability. By changing the voltage value loaded on both sides of the liquid crystal layer, the continuous adjustment of the unit state is achieved, thereby improving the flexibility of adjustment.

[0072] Those skilled in the art will also appreciate that the various illustrative logical blocks and steps listed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of the present application.

[0073] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs. When the computer program is loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer program can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer program can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0074] Those skilled in the art will understand that the various numerical numbers such as first and second involved in this application are only for the convenience of description and are not used to limit the scope of the embodiments of this application, and also indicate the order of precedence.

[0075] In this application, at least one can also be described as one or more, and multiple can be two, three, four or more, which is not limited in this application. In the embodiments of this application, for a technical feature, the technical features in the technical feature are distinguished by "first", "second", "third", "A", "B", "C" and "D", and there is no order of precedence or size between the technical features described by "first", "second", "third", "A", "B", "C" and "D".

[0076] The correspondences shown in the tables in this application can be configured or predefined. The values ​​of the information in each table are examples only and can be configured to other values, which are not limited by this application. When configuring the correspondence between information and parameters, it is not necessarily required to configure all the correspondences shown in each table. For example, in the tables in this application, the correspondences shown in certain rows may not be configured. For another example, appropriate deformation adjustments can be made based on the above tables, such as splitting, merging, etc. The names of the parameters shown in the titles of the above tables can also use other names that can be understood by the communication device, and the values ​​or representations of the parameters can also use other values ​​or representations that can be understood by the communication device. When implementing the above tables, other data structures can also be used, such as arrays, queues, containers, stacks, linear lists, pointers, linked lists, trees, graphs, structures, classes, heaps, hash tables or hash tables, etc.

[0077] The predefined in this application may be understood as defined, predefined, stored, pre-stored, pre-negotiated, pre-configured, solidified, or pre-burned.

[0078] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0079] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0080] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A metasurface unit, characterized in that: include: metallic formations; a liquid crystal layer, the liquid crystal layer being disposed on the metal layer; At least one metal patch is arranged on a side of the liquid crystal layer away from the metal ground layer, the at least one metal patch is connected to a power supply through a bias line, the at least one metal patch is rectangular, and the long sides of the at least one metal patch extend in the same direction.

2. The method according to claim 1, wherein The metal stratum and the at least one metal patch are used as reflectors and / or scatterers of the metasurface unit to reflect and / or scatter an incident beam.

3. The method according to claim 1, wherein Different metal patches have different sizes, and metal patches of different sizes correspond to different operating frequency bands; The metal patch is used to reflect and / or scatter an incident beam whose frequency belongs to a working frequency band corresponding to the metal patch.

4. The method according to claim 3, wherein Different metal patches have different lengths; and / or Different metal patches have different widths.

5. The method according to claim 3, wherein The at least one metal patch includes a first metal patch and a second metal patch, and the first metal patch and the second metal patch have different sizes.

6. The method according to claim 1, wherein The reflection and / or scattering amplitude and the reflection and / or scattering phase of the metasurface unit are continuously adjustable through the liquid crystal layer; The reflection and / or scattering amplitude and the reflection and / or scattering phase of the incident beam by the metasurface unit are related to the dielectric constant of the liquid crystal layer, and the dielectric constant of the liquid crystal layer is related to the voltage of the power supply; The metasurface unit is used to adjust the dielectric constant of the liquid crystal layer by adjusting the voltage of the power supply, thereby adjusting the reflection and / or scattering amplitude and reflection and / or scattering phase of the metasurface unit for the incident beam.

7. The method according to claim 1, wherein The metasurface unit further includes: a first substrate, the first substrate being disposed on a side of the metal layer away from the liquid crystal layer; A second substrate is provided on a side of the at least one metal patch away from the liquid crystal layer.

8. The method according to claim 7, wherein The first substrate and the second substrate are made of glass.

9. A metasurface, characterized in that include: At least one metasurface unit as described in any one of claims 1-8 above.

10. The method according to claim 9, wherein At least one metasurface unit is arranged in a matrix.

11. The method according to claim 9 or 10, wherein: The deflection angle of the reflected and / or scattered beam of the metasurface is continuously adjustable; The deflection angle of the reflected and / or scattered beam of the metasurface is related to the phase period of the metasurface, and the phase period of the metasurface is related to the dielectric constant of the liquid crystal layer in each metasurface unit of the metasurface; The metasurface is used to adjust the phase period of the metasurface by adjusting the dielectric constant of the liquid crystal layer in different metasurface units of the metasurface, thereby adjusting the reflection and / or scattering beam deflection angle of the metasurface.

12. The method according to claim 11, wherein The metasurface is also used to adjust the phase period of the metasurface by adjusting the dielectric constants of the liquid crystal layers in the metasurface units in the same column or row to be the same, and adjusting the dielectric constants of the liquid crystal layers in the metasurface units in different rows or columns to be different or the same.

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