Total-space continuously adjustable metasurface for B5G and 6G

Abstract

The invention relates to a full-space continuous adjustable metasurface for B5G and 6G, the metasurface comprises a plurality of metasurface units, and each metasurface unit comprises a dielectric substrate, a metal structure and an adjustable material (such as liquid crystal, graphene and the like); the metal structures generate resonance response of a target frequency band, the metal structures are arranged on the dielectric substrate, and the adjustable material is combined with the metal structures to be filled between the two layers of metal structures, or arranged on the same layer as the metal structures, or connected with the upper layer and the lower layer of the metal structures. Compared with the prior art, the device is continuously adjustable in the whole space of the B5G and 6G high-frequency wave bands, and achieves the precise control of electromagnetic waves in the whole space range. Efficiency is high, production cost is reduced, operation is simple, and working frequency is high. The invention discloses a high-frequency full-space continuous adjustable metasurface device, which only takes a liquid crystal material as an example. In addition, the function can also be realized by using graphene and other continuous tunable materials for regulation and control.

Description

Technical Field

[0001] The present invention relates to a metasurface, and in particular to a full-space continuously adjustable metasurface for B5G and 6G. Background Art

[0002] With the rapid development of global mobile communication technology, 5G technology has been commercialized and widely used in all walks of life. However, with the continuous advancement of social digitization and intelligence, the existing 5G technology has certain limitations in responding to future needs. For example, with the increase in the number of smart devices and the popularity of data-intensive applications, global data traffic is exploding. In the face of such huge data demand, the existing 5G technology is difficult to provide sufficient bandwidth and speed. In addition, the spectrum resources in the low-frequency and mid-frequency bands are already very crowded, and the existing spectrum resources are difficult to meet the growing demand for wireless communications. B5G (Beyond 5G) and 6G technology are the natural extension and development of 5G technology, aiming to solve the limitations of existing 5G technology and meet the complex and diverse application needs of the future. By developing B5G and 6G technology, the shortage of spectrum resources can also be alleviated, providing connections for more users and devices. B5G and 6G technology include millimeter waves and terahertz waves in higher frequency bands, which will provide higher data transmission rates to meet future data needs. Therefore, it is necessary to study B5G and 6G technology, which will promote the further development of mobile communication technology.

[0003] Traditional optical components are based on the principle of refraction, reflection, transmission or diffraction of light, and control light waves by giving the refractive index of the medium during propagation, such as lenses, wave plates, optical modulators, etc. The optical devices manufactured in this way are relatively bulky and no longer suitable for today's requirements for integration and miniaturization. However, the planar two-dimensional metasurface with sub-wavelength thickness can achieve the purpose of manipulating electromagnetic waves through the design of the structure, and then realize various functions, so metasurfaces have developed rapidly. Traditional metasurfaces have fixed topological geometric structures, that is, once the physical structure of the metasurface is processed and formed, it can only realize a certain specific function and cannot be changed in real time according to the needs. In some practical application scenarios, it is usually required that the metasurface can switch different functions in real time. In order to realize tunable functions, tunable materials or devices are integrated into the same metasurface device, which can realize flexible switching of different functions, thereby effectively reducing the production cost of the metasurface and broadening its application range. So far, active metasurfaces have been widely used in positive and negative intrinsic diodes (PIN) and varactor diodes in the microwave band. However, diodes cannot work at high frequencies. Therefore, it is necessary to focus on other methods, such as micro-electromechanical systems, and tunable materials (liquid crystal, graphene and vanadium dioxide), which have the characteristics of changing their physical properties in response to external stimuli (such as electric field, temperature, light, etc.). Among these tunable materials, most of the control methods are based on discontinuous adjustment of two states, but the metasurface based on liquid crystal and graphene can be continuously adjustable with voltage, which can flexibly adjust the amplitude and phase of electromagnetic waves, and has many applications in high-frequency bands.

[0004] Most existing tunable metasurfaces focus on half-space beam modulation, such as the adjustment of reflection or transmission direction, which hinders the application of metasurface devices. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a full-space continuously adjustable metasurface for B5G and 6G, which realizes the precise control of electromagnetic waves in the whole space (from reflection to transmission); it has high efficiency, reduces production costs, is simple to operate, and has a high operating frequency.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention achieves continuous regulation of electromagnetic waves in the entire space by adjusting the tunable material to change the material properties. For example, for adjustable material liquid crystal, the arrangement state of the liquid crystal molecules can be continuously changed by applying an external voltage, thereby changing the dielectric constant of the liquid crystal, thereby achieving regulation of the incident electromagnetic waves. By designing the unit structure and continuously regulating the liquid crystal material, a beam deflection function with high efficiency is achieved in the transmission mode, and an imaging function is achieved in the reflection mode. It has excellent electromagnetic wave regulation performance in the entire space and has potential applications in B5G and 6G communications, imaging, sensing, etc.

[0008] At present, most of the control methods are discontinuous tuning of two states. The present invention uses continuously tunable materials, produces resonant response of the target frequency band through the designed metal structure and combines the continuous adjustability of the adjustable material. In the transmission mode, the radiation loss is significantly suppressed to achieve a higher transmittance, and the steep phase dispersion caused by the frequency response caused by the metal structure can achieve a large frequency shift and thus produce a phase difference with high transmittance. At the same time, due to the frequency shift, a large modulation depth can also be obtained in the reflection mode. The continuous adjustability of the adjustable material is used to realize the full-space free control of the electromagnetic wave beam, and the coding unit is used to achieve a high-efficiency beam deflection in the transmission mode, and near-field imaging in the reflection mode.

[0009] The present invention provides a full-space continuously adjustable metasurface for B5G and 6G, wherein the metasurface comprises a plurality of metasurface units, and the metasurface units comprise: a dielectric substrate, a metal structure, and an adjustable material (such as: graphene, liquid crystal, etc.).

[0010] The metal structure generates a resonant response in the target frequency band, and the metal structure is arranged on the dielectric substrate. The tunable material is combined with the metal structure in the form of filling between two layers of metal structures, or in the same layer as the metal structure, or connected to the upper and lower layers of the metal structure. The role of the dielectric substrate is to provide a solid foundation to support the deposition and production of other layers, and it has low loss and high transmittance in the high-frequency band, ensuring that the overall performance of the device is not limited by the substrate material.

[0011] The metal structure is the core part of the metasurface. By designing and arranging specific geometric shapes, the modulation and manipulation of terahertz waves can be achieved. The metal structure produces a resonant response in the target frequency band, and the asymmetric metal structure designed in the present invention excites a stronger resonant response. In conventional resonant structures, the radiation loss of electromagnetic waves is usually large, resulting in reduced transmission efficiency. The metal structure designed by the present invention can reduce radiation loss and enhance interaction with electromagnetic waves, thereby achieving the required phase shift and amplitude modulation.

[0012] Furthermore, the metasurface includes periodically arranged metasurface units. Through a designed coding sequence, the generalized Snell's reflection law is applied to the coded metasurface in the transmission mode, and the angle-dependent coding sequence is assigned to the array to change the phase distribution of the array so that the electromagnetic waves are transmitted at a desired angle; in the reflection mode, amplitude modulation is used to achieve near-field imaging through a designed coding sequence.

[0013] Furthermore, the metasurface unit is composed of a metal-insulator-metal resonator structure, and the size of the metasurface unit p<λ / 2 (λ is the wavelength of the target frequency).

[0014] Furthermore, the metal structure has a thickness of 100 nm to 300 nm.

[0015] Furthermore, the metal structure is arranged on a dielectric substrate.

[0016] Furthermore, the adjustable material takes liquid crystal as an example, the thickness of the polyimide is 0.1 μm, and the polyimide is spin-coated on the metal structure.

[0017] Furthermore, the adjustable material takes liquid crystal as an example, and 30-60 μm of liquid crystal is filled between the two layers of polyimide.

[0018] Polyimide is often used as a liquid crystal molecule alignment layer. During the manufacturing process, the polyimide layer is spin-coated on the metal structure and rubbed to determine the initial orientation of the liquid crystal molecules. This layer of polyimide ensures that the liquid crystal molecules are evenly aligned above it and can respond accurately when an electric field is applied, thereby achieving effective control of the liquid crystal layer.

[0019] The liquid crystal layer is an adjustable core material. The arrangement of liquid crystal molecules can be changed by an external electric field, thereby changing the dielectric constant of the liquid crystal. This layer of liquid crystal can dynamically adjust the phase and amplitude of the incident terahertz wave.

[0020] Furthermore, tunable materials such as liquid crystal, graphene and vanadium dioxide can change their physical properties in response to external stimuli (such as electric field, temperature, light, etc.), thereby realizing the dynamic adjustability of the metasurface. Most tunable materials can only achieve discontinuous adjustability in two states. For example, vanadium dioxide is a material with phase change characteristics, and its conductivity and optical properties can be adjusted by temperature changes. Through temperature control, VO can be dynamically controlled. 2 The phase transition from insulating state to metallic state, but VO 2There are only two adjustable states: insulating state and metallic state. However, in some specific applications, liquid crystal and graphene materials are required to continuously tune materials to meet different functions, so there are many applications in high-frequency bands. Graphene is a two-dimensional material with a single layer of carbon atoms, which has excellent electrical conductivity and optical properties. Through continuous regulation of external voltage, the carrier concentration of graphene can be adjusted, thereby continuously changing its conductivity and optical response. The present invention takes liquid crystal as an example of a tunable material, but it can also be applied to other tunable materials and methods.

[0021] In a typical capacitor arrangement, the liquid crystal unit is sandwiched between two metal layers with no bias applied. The initial orientation of the liquid crystal molecules is controlled by coating a polyimide film layer (commonly called a pre-orientation film) to control the liquid crystal molecules to be in the same direction, parallel to the pre-orientation film. As the voltage increases, the orientation of the liquid crystal changes continuously from the initial direction parallel to the metal plate to the direction perpendicular to the metal plate. The change in the orientation of the liquid crystal molecules will eventually produce a change in the relative dielectric constant. The relative dielectric constant tensor of the liquid crystal in the unbiased case is described as follows:

[0022]

[0023] where ε ∥ is the dielectric constant along the long axis of the liquid crystal, ε ⊥ is the dielectric constant along the short axis of the liquid crystal;

[0024] When in the saturated state, the liquid crystal is oriented perpendicular to the metal layer, and the relative dielectric constant tensor of the liquid crystal is:

[0025]

[0026] Since the effective dielectric constant ε = ε z , so when the bias voltage increases from 0V to the threshold voltage, it changes from ε ⊥ Increase to ε ∥ , the liquid crystal changes continuously with the voltage, and the effective dielectric constant is ε ⊥ to ε ∥ Any value between . It can be seen that as the bias voltage intensity changes, the dielectric constant of the liquid crystal in different states can be changed. The change of the effective dielectric constant causes the frequency deviation of the electromagnetic response. Therefore, if the phase response of the element changes greatly with frequency, the frequency deviation will cause a large phase shift. The effective dielectric constant of the liquid crystal used in the present invention is: 2.55≤ε≤3.65.

[0027] Furthermore, in the transmission mode, beam splitting is achieved by tuning the liquid crystal and changing the coding period sequence to control the direction of the electromagnetic wave. Beam control in the transmission mode:

[0028] The beam splitting angle of the beam control of the present invention is based on the generalized Snell's theorem:

[0029]

[0030] Among them, θ t ,θ i The refraction angle and incident angle of the electromagnetic wave, n i is the refractive index of the incident medium, λ 0 is the wavelength in vacuum, is the phase gradient generated by the unit. From the generalized Snell's law, it can be seen that at the incident angle θ i Given the situation, by changing the phase gradient Achieve deflection at any angle; Since the incident wave in the present invention is incident vertically from the air, that is, the incident angle θ i =0,n i =1, the refraction angle can be derived from the generalized Snell refraction law:

[0031]

[0032] Furthermore, in the reflection mode, by amplitude modulating the coding unit structure, a light-dark contrast image is obtained in the near field, namely, near-field imaging in the reflection mode:

[0033] The ability of a metasurface to modulate electromagnetic waves can be expressed by the modulation depth MD, which is defined as:

[0034] MD=(Q 1 -Q 0 ) / (Q 1 +Q 0 ),

[0035] Q 1 and Q 0 They are the highest reflectivity and the lowest reflectivity at the operating frequency respectively.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] (1) Wide range of applications: The metasurface structure designed in the present invention generates a resonant response through the designed asymmetric metal structure and combines with continuously tunable materials to realize beam splitting in the transmission mode and near-field imaging in the reflection mode, thereby achieving precise control of electromagnetic waves in the entire spatial range (from reflection to transmission).

[0038] (2) Reduce production costs: Compared with half-space (reflection or transmission) tunable metasurfaces, full-space tunable metasurfaces can achieve efficient energy utilization and minimize energy loss, which is of great significance for improving system performance and energy saving.

[0039] (3) Simple operation: The integrated metasurface structure can change the resonant response of the unit structure by simply changing the voltage. After subsequent combination with FPGA coding, the state of each unit structure can be conveniently controlled to achieve different adjustable functions.

[0040] (4) High operating frequency: The designed unit structure operates in the high frequency band and has potential applications in B5G and 6G millimeter wave and terahertz communications, imaging, and sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of the working principle of the entire metasurface based on an embodiment of the present invention;

[0042] Figure 2 is a schematic diagram of the structure of a liquid crystal supersurface microstructure unit based on an embodiment of the present invention; wherein a is a schematic diagram of the three-dimensional structure of the microstructure unit, and b is a schematic diagram of the metal structure of the microstructure unit;

[0043] Figure 3 The simulated scattering amplitude intensity and phase corresponding to the microstructure unit whose effective dielectric constant of the liquid crystal is changed to 2.55 and 3.65 in the transmission mode of the embodiment of the present invention;

[0044] Figure 4 The simulated scattering amplitude intensity and phase corresponding to the microstructure unit whose effective dielectric constant of the liquid crystal is changed to 2.7 and 3.65 under the reflection mode of the embodiment of the present invention;

[0045] Figure 5 This is an example of simulation results in the transmission mode of a unit period array according to an embodiment of the present invention; wherein a is a specific coding period sequence diagram, and b is a far-field schematic diagram of beam splitting generated by coding;

[0046] Figure 6 is a schematic diagram of near-field imaging in a coding sequence reflection mode based on an embodiment of the present invention;

[0047] Figure numerals: 1 - quartz substrate; 2 - metal structure; 3 - polyimide; 4 - liquid crystal. DETAILED DESCRIPTION

[0048] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0049] Example 1

[0050] This embodiment provides a full-space continuously adjustable metasurface for B5G and 6G, wherein the metasurface includes a plurality of metasurface units, such as Figure 2As shown in a, the metasurface unit includes: a quartz substrate 1, a metal structure 2, a polyimide 3 and a liquid crystal 4;

[0051] The metal structure 2 includes an asymmetric split ring. The metal structure 2 is disposed on the quartz substrate 1 . The polyimide 3 is disposed on the metal structure 2 . The liquid crystal 4 is filled between two layers of the polyimide 3 .

[0052] The quartz substrate 1 provides a solid foundation to support the deposition and fabrication of other layers, and it has low loss and high transmittance in the high-frequency band, ensuring that the overall performance of the device is not limited by the substrate material.

[0053] The metal structure 2 is the core part of the metasurface. By designing and arranging specific geometric shapes, the terahertz wave can be modulated and manipulated. The asymmetric metal structure designed by the present invention excites the resonant response. In conventional resonant structures, the radiation loss of electromagnetic waves is usually large, resulting in reduced transmission efficiency. The metal structure designed by the present invention can reduce the radiation loss and enhance the interaction with electromagnetic waves, thereby achieving the required phase shift and amplitude modulation.

[0054] Polyimide 3 is often used as a liquid crystal molecule alignment layer. During the manufacturing process, the polyimide layer is spin-coated on the metal structure and rubbed to determine the initial orientation of the liquid crystal molecules. This layer of polyimide ensures that the liquid crystal molecules are evenly aligned above it and can respond accurately when an electric field is applied, thereby achieving effective control of the liquid crystal layer.

[0055] The liquid crystal layer 4 is a controllable core material. The arrangement of the liquid crystal molecules can be changed by an external electric field, thereby continuously changing the dielectric constant of the liquid crystal. This layer of liquid crystal can dynamically adjust the phase and amplitude of the incident terahertz wave.

[0056] In a specific embodiment, Figure 1 As shown, the metasurface includes periodic metasurface units. Through a designed coding sequence, the generalized Snell's reflection law is applied to the coding metasurface in the transmission mode, and the angle-dependent coding sequence is assigned to the array to change the phase distribution of the array so that the electromagnetic waves are transmitted at a desired angle; in the reflection mode, amplitude modulation is used to achieve near-field imaging through a designed coding sequence.

[0057] In a specific embodiment, the metasurface unit is composed of a metal-insulator-metal resonator structure, and the metasurface unit size p<λ / 2 (λ is the wavelength of the target frequency).

[0058] In a specific implementation, the metal structure 2 has a thickness of 0.3 μm.

[0059] In a specific embodiment, Figure 2As shown in b, in order to achieve a resonant response at THz, an asymmetric metal structure is used, wherein w = 10 μm, w1 = 30 μm, w2 = 50 μm, l1 = 15 μm, l2 = 20 μm. The metal structure 2 is provided on a quartz substrate 1 of 150 μm.

[0060] In a specific implementation, the thickness of the polyimide 3 is 0.1 μm, and the polyimide 3 is spin-coated on the metal structure 2 .

[0061] In a specific implementation, a 60 μm liquid crystal 4 is filled between the two layers of polyimide 3 .

[0062] In a specific implementation manner, the present invention takes liquid crystal as an example of a tunable material.

[0063] In a typical capacitor arrangement, the liquid crystal cell is sandwiched between two metal layers with no bias applied. The initial orientation of the liquid crystal molecules is controlled by coating a polyimide film layer (commonly called a pre-orientation film) to control the liquid crystal molecules to face the same direction, parallel to the pre-orientation film. As the voltage increases, the orientation of the liquid crystal changes continuously from the initial direction parallel to the metal plate to the direction perpendicular to the metal plate. The change in the orientation of the liquid crystal molecules will eventually produce a change in the relative dielectric constant. The relative dielectric constant tensor of the liquid crystal 4 in the unbiased case is described as follows:

[0064]

[0065] where ε ∥ is the dielectric constant of the liquid crystal along its long axis, ε ⊥ is the dielectric constant of the liquid crystal 4 in the short axis direction;

[0066] When in saturation bias, the liquid crystal 4 is oriented perpendicular to the metal layer, and the relative dielectric constant tensor of the liquid crystal 4 is:

[0067]

[0068] Since the effective dielectric constant ε = ε z , so when the bias voltage increases from 0V to the threshold voltage, it changes from ε ⊥ Increase to ε ∥ , the liquid crystal 4 changes continuously with the voltage, and the effective dielectric constant is ε ⊥ to ε ∥ Any value between . It can be seen that as the bias voltage intensity changes, the dielectric constant of the liquid crystal 4 can be changed in different states. The change of the effective dielectric constant causes the frequency deviation of the electromagnetic response. Therefore, if the phase response of the element changes greatly with frequency, the frequency deviation will cause a large phase shift. The effective dielectric constant of the liquid crystal 4 used in the present invention is: 2.55≤ε≤3.65.

[0069] In a specific embodiment, beam steering in transmission mode:

[0070] The beam splitting angle of the beam control of the present invention is based on the generalized Snell's theorem:

[0071]

[0072] Among them, θ t ,θ i The refraction angle and incident angle of the electromagnetic wave, n i is the refractive index of the incident medium, λ 0 is the wavelength in vacuum, is the phase gradient generated by the unit. From the generalized Snell's law, it can be seen that at the incident angle θ i Given the situation, by changing the phase gradient Achieve deflection at any angle; Since the incident wave in the present invention is incident vertically from the air, that is, the incident angle θ i =0,n i =1, the refraction angle can be derived from the generalized Snell refraction law:

[0073]

[0074] In a specific embodiment, the metasurface operates at a frequency of 0.529 THz. Figure 3 As shown in FIG. 1 , by changing the effective dielectric constant of liquid crystal 4 to 2.55 and 3.65, two unit structures with a transmittance of about 0.65 and a phase difference of 184° can be obtained. By using the concept of encoding metasurface, the two unit structures with dielectric constants of liquid crystal 4 of 2.55 and 3.65 are defined as "0" and "1", respectively. Figure 5 As shown in a, the coding sequence 000111000111000111000111 is applied to the entire metasurface, so that the transmitted electromagnetic wave generates Figure 5 The beam splitting angle of about 36° shown in b is completely consistent with the theoretical value. By changing different coding period sequences, beam splitting at different angles can be achieved, and the direction of the electromagnetic wave can be controlled more flexibly;

[0075] Near-field imaging in reflection mode:

[0076] The ability of a metasurface to modulate electromagnetic waves can be expressed by the modulation depth MD, which is defined as:

[0077] MD=(Q 1 -Q 0 ) / (Q 1 +Q 0 ),

[0078] Q 1 and Q0 are the highest reflectivity and the lowest reflectivity at the operating frequency respectively. Figure 4 As shown, at 0.566THz, the reflection coefficients of the liquid crystal 4 with dielectric constants of 3.65 and 2.7 are 0.963 and 0.194 respectively, the phase difference is 0°, and the modulation depth of the tunable liquid crystal metasurface of the present invention is 66.5%. The two unit structures with dielectric constants of 2.7 and 3.65 of the liquid crystal 4 are defined as "0" and "1" respectively. Due to the influence of the modulation depth, by arranging these two unit structures, a light and dark contrast image can be obtained in the field, but due to the influence of the coupling between the units, the image inevitably cannot reach the ideal state. Figure 5 As shown, the units displayed by the letters "S" and "U" are coded as "1" and marked with white boxes, and the other structural units are coded as "0". The image is imaged in the near field, such as Figure 6 shown.

[0079] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0080] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A fully space continuously adjustable metasurface for B5G and 6G, characterized in that: The metasurface includes a plurality of metasurface units, each of which includes: a dielectric substrate, a metal structure, and an adjustable material; The adjustable material can achieve full-space continuous adjustment.

2. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: The metasurface includes periodically arranged metasurface units. Through a designed coding sequence, the generalized Snell's reflection law is applied to the coding metasurface in the transmission mode, and the angle-related coding sequence is assigned to the array to change the phase distribution of the array and deflect the electromagnetic wave at a desired angle; in the reflection mode, amplitude modulation is used to achieve near-field imaging through a designed coding sequence.

3. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: The metasurface unit is composed of a metal-insulator-metal resonator structure; the resonant response of the target frequency band is generated by the metal structure and the continuous adjustability of the adjustable material is combined, the radiation loss is significantly suppressed in the transmission mode to achieve a higher transmittance, and the steep phase dispersion caused by the resonant response can achieve a large frequency shift and thus produce a phase difference with high transmittance. At the same time, due to the frequency shift, a larger modulation depth can also be obtained in the reflection mode.

4. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: The dielectric substrate provides a solid foundation that supports the deposition and fabrication of other layers.

5. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: The metal structure generates a resonant response in a target frequency band and is disposed on the dielectric substrate.

6. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: The adjustable material is combined with the metal structure in the form of filling between two layers of the metal structure, or being in the same layer as the metal structure, or being connected to the upper and lower layers of the metal structure.

7. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: Continuous beamforming control is achieved through adjustable materials. Taking liquid crystal materials as an example, the state of liquid crystal molecules changes continuously with voltage, and the effective dielectric constant can be taken as ε ⊥ to ε ∥ The change of the effective dielectric constant produces a frequency deviation of the electromagnetic response, achieving continuous beam control.

8. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: In the transmission mode, by tuning the adjustable material, finding the corresponding coding unit, changing the coding period sequence to achieve beam splitting and control the direction of the electromagnetic wave; Beam control in the transmission mode: Beam steering and its beam splitting angle are based on the generalized Snell's theorem: Among them, θ t ,θ i The refraction angle and incident angle of the electromagnetic wave, n i is the refractive index of the incident medium, λ0 is the wavelength in vacuum, is the phase gradient produced by the unit; from the generalized Snell's law, at an incident angle θ i Given the situation, by changing the phase gradient Achieve deflection at any angle; Since the incident wave in the present invention is incident vertically from the air, that is, the incident angle θ i =0,n i =1, the refraction angle can be derived from the generalized Snell refraction law 9. The full-space continuously adjustable metasurface for B5G and 6G according to claim 1, characterized in that: In the reflection mode, by tuning the adjustable material, the coding unit structure is found by using amplitude modulation. By arranging the coding unit structure, a light-dark contrast image is obtained in the near field, that is, the near-field imaging of the reflection mode: The ability of a metasurface to modulate electromagnetic waves can be expressed by the modulation depth MD, which is defined as: MD=(Q1-Q0) / (Q1+Q0), Q1 and Q0 are the highest and lowest reflectivity at the operating frequency, respectively.

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