An electromagnetic wave amplitude and phase regulation method

Abstract

The present invention relates to a method for electromagnetic amplitude and phase regulation, belonging to the technical field of metasurface electromagnetic regulation, and solves the problems in the prior art that to achieve full-range independent and continuous amplitude and phase regulation of electromagnetic waves, it is necessary to change the structural size parameters, the regulation method lacks theoretical support, the regulation is complex, and the efficiency is low. The method includes the following steps: arranging a plurality of metasurface unit structures in the form of a two-dimensional array; the metasurface unit structure includes cascaded first meta-structures and second meta-structures with the same structure; adjusting the orientation angles of the first meta-structure and the second meta-structure according to the amplitude and phase to be regulated at the position where the metasurface unit structure is located, so that the difference and sum of the orientation angles of the first meta-structure and the second meta-structure respectively correspond to the amplitude and phase to be regulated. This regulation method can achieve independent and continuous regulation of the amplitude and phase of electromagnetic waves by changing the orientation angles of the meta-structures, without changing the size parameters of the unit structures, and the regulation method is simple, flexible, and efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of metasurface electromagnetic regulation, and in particular to a method for regulating the amplitude and phase of electromagnetic waves. Background Art

[0002] With the development of science and technology, scientific research and technological inventions based on electromagnetic waves have penetrated into all aspects of human daily life, and have extensive applications especially in the fields of communication, imaging, navigation, detection, etc. Amplitude, phase, and polarization, as the basic properties of electromagnetic waves, determine the nature of electromagnetic wave propagation. How to efficiently regulate the amplitude and phase of electromagnetic waves has always been a hot issue in the field of electromagnetic wave research. In recent years, there have been more and more works on flexibly regulating electromagnetic waves by designing unit structures to construct metasurfaces. The key to designing a metasurface lies in the regulation of the scattering characteristics of the unit structure for the phase, amplitude, polarization, and their combinations of electromagnetic waves. In recent years, there have been many methods for designing amplitude-phase regulation units to regulate the amplitude and phase of electromagnetic waves. This kind of amplitude-phase regulation method has a significant regulation effect. For example, it can improve the resolution of holographic imaging, achieve directional radiation, radar cross-section reduction, multi-beam design, etc. By changing the regulation of multiple degrees of freedom such as the size and orientation of the unit structure, the modulation of the complex amplitude of electromagnetic waves can be realized. However, it is still very necessary to find an accurate and general regulation method to realize the full-range complex amplitude modulation of the unit structure.

[0003] At present, there are various methods for regulating the amplitude and phase of electromagnetic waves. One is based on the unit structure of the Huygens metasurface, and the complex amplitude modulation is realized by changing the electromagnetic response by regulating the unit structure size; the second is to use the rotation of the unit structure to realize the linear polarization amplitude-phase regulation with binary phase modulation; the third is to use the pure-phase metasurface of the circular cross-polarization phase regulation unit structure based on the geometric phase Pancharatnam-Berry (PB) principle for regulation; the fourth is to use the included angle and rotation of the two arms of the X-shaped structure to realize the full-range amplitude-phase regulation.

[0004] The prior art has at least the following defects. First, the regulation method based on the Huygens metasurface can only efficiently regulate the amplitude of electromagnetic waves, and the metasurface structure unit is complex, lacking a general regulation rule. Second, when regulating based on the linear polarization amplitude-phase regulation metasurface with binary phase modulation, only binary phases can be obtained. To realize the full-range independent and continuous regulation of the amplitude and phase, the size of the unit structure needs to be adjusted. Third, when regulating based on the circular cross-polarization phase regulation unit structure of the geometric phase Pancharatnam-Berry (PB) principle, it is necessary to change the size parameters of the unit structure to regulate the amplitude, and there is no corresponding regulation rule for the regulation of the unit structure size, and the regulation efficiency is low. Fourth, although the X-shaped unit structure can support the full-range regulation of the amplitude and phase, its efficiency is not high and the coupling effect of its unit structure also lacks corresponding theoretical support. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a method for modulating the amplitude and phase of electromagnetic waves, so as to solve the problems in the prior art that changing the structural size parameters is required for full-range independent and continuous amplitude and phase modulation of electromagnetic waves, the modulation method lacks theoretical support, the modulation is complex, and the efficiency is low.

[0006] The present invention provides a method for modulating the amplitude and phase of electromagnetic waves, comprising the following steps:

[0007] Arrange a plurality of metasurface unit structures in the form of a two-dimensional array; the metasurface unit structure includes cascaded first meta-structures and second meta-structures with the same structure;

[0008] Adjust the orientation angles of the first meta-structure and the second meta-structure according to the amplitude and phase to be modulated at the position where the metasurface unit structure is located, so that the difference between the orientation angles of the first meta-structure and the second meta-structure corresponds to the amplitude to be modulated, and the sum of the orientation angles of the first meta-structure and the second meta-structure corresponds to the phase to be modulated.

[0009] Further, adjust the orientation angles of the first meta-structure and the second meta-structure according to the following corresponding relationship, so that the difference between the orientation angles of the first meta-structure and the second meta-structure corresponds to the amplitude to be modulated:

[0010] A = cos(θ2 - θ1)

[0011] where θ1 represents the orientation angle of the first meta-structure, θ2 represents the orientation angle of the second meta-structure, and A represents the amplitude to be modulated.

[0012] Further, adjust the orientation angles of the first meta-structure and the second meta-structure according to the following corresponding relationship, so that the sum of the orientation angles of the first meta-structure and the second meta-structure corresponds to the phase to be modulated:

[0013]

[0014] where, when the incident wave is a right-handed circularly polarized electromagnetic wave and the transmitted wave is a left-handed circularly polarized electromagnetic wave, σ = 1; when the incident wave is a left-handed circularly polarized electromagnetic wave and the transmitted wave is a right-handed circularly polarized electromagnetic wave, σ = -1, represents the phase to be modulated.

[0015] Further, when the orientation angle θ1 of the first element structure to be adjusted is greater than 0, the symmetry axis of the C-shaped hole resonator ring in the first element structure is rotated counterclockwise by a corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ1 of the first element structure; if the orientation angle θ1 of the first element structure to be adjusted is less than 0, the symmetry axis of the C-shaped hole resonator ring in the first element structure is rotated clockwise by a corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ1 of the first element structure.

[0016] If the orientation angle θ2 of the second element structure to be adjusted is greater than 0, the symmetry axis of the C-shaped hole resonator ring in the second element structure is rotated counterclockwise by a corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ2 of the second element structure; if the orientation angle θ2 of the second element structure to be adjusted is less than 0, the symmetry axis of the C-shaped hole resonator ring in the second element structure is rotated clockwise by a corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ2 of the second element structure.

[0017] Further, both the first element structure and the second element structure include a dielectric substrate and two identical circular conductor patches symmetrically attached to both sides of the dielectric substrate; wherein,

[0018] The dielectric substrate and the two circular conductor patches have the same geometric center; and, a C-shaped hole resonator ring is provided on the circular conductor patch, and the material of the circular conductor patch is the corresponding perfect electric conductor in this electromagnetic wave frequency band.

[0019] Further, an air layer is provided between the first element structure and the second element structure.

[0020] Further, the value range of the thickness of the air layer between the first element structure and the second element structure is [4.75 mm, 5.25 mm].

[0021] Further, the value range of the thickness of the circular conductor patch is [0.0171 mm, 0.0189 mm], the value range of the radius is [3.325 mm, 3.675 mm], the value range of the inner radius of the C-shaped hole resonator ring is [2.85 mm, 3.15 mm], the value range of the outer radius is [3.04 mm, 3.36 mm], and the value range of the corresponding partition width of the C-shaped hole resonator ring is [0.19 mm, 0.21 mm].

[0022] Further, the dielectric substrate is a square structure, and the value range of its thickness is [1.425 mm, 1.575 mm].

[0023] Further, the electromagnetic wave amplitude and phase modulation method can be used for beam generation modulation, holographic imaging modulation, or beam focusing modulation.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] 1. For the electromagnetic wave amplitude and phase modulation method proposed by the present invention, by setting the orientation angles of the two meta-structures in the metasurface unit structure, independent and continuous modulation of the amplitude and phase of the electromagnetic wave can be achieved without changing the size of the unit structure. The modulation method is flexible, has high modulation efficiency, and can achieve full-range modulation of the electromagnetic wave amplitude in the range of [0, 1] and full-range modulation of the electromagnetic wave phase in the range of [0°, 360°].

[0026] 2. For the electromagnetic wave amplitude and phase modulation method proposed by the present invention, the metasurface unit structure used modulates the amplitude and phase of the electromagnetic wave based on the wave plate theory and the PB phase theory, which has a perfect theoretical support. Moreover, it does not rely on randomly changing the structural parameters to modulate the amplitude and phase of the electromagnetic wave. Based on this modulation method, the amplitude and phase modulation requirements of various modulation devices can be met, such as dual-focusing lenses, multi-beam generators, Bessel beam generators, and holographic imaging devices, etc. This modulation method has strong applicability and a wide range of application scenarios. By changing the electrical size of the metasurface unit structure to match the materials of the corresponding circular conductor patches and dielectrics, amplitude and phase modulation of electromagnetic waves in multiple frequency bands such as the microwave band, infrared band, terahertz band, and optical frequency band can be achieved.

[0027] 3. For the electromagnetic wave amplitude and phase modulation method proposed by the present invention, the structural sizes of the metasurface unit structures used are all the same, and only the orientation angles of the two meta-structures are different, which simplifies the manufacturing process of the two-dimensional array and greatly reduces the manufacturing cost.

[0028] In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combined solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages will become obvious from the description, or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained from the content specifically pointed out in the description and the drawings. Description of the Drawings

[0029] The drawings are only for the purpose of showing specific embodiments and are not considered to be a limitation of the present invention. Throughout the drawings, the same reference signs represent the same components.

[0030] Figure 1 is a flowchart of the electromagnetic wave amplitude and phase modulation method according to an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the rotation of two cascaded quarter-wave plates according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the geometric phase change of the Poincaré sphere representation in the embodiment of the present invention;

[0033] Figure 4 Schematic diagram of the metasurface unit structure in the embodiment of the present invention;

[0034] Figure 5 Schematic diagram of the meta-structure in the metasurface unit structure in the embodiment of the present invention;

[0035] Figure 6 Schematic diagram of the amplitude of the electromagnetic wave transmission coefficient and the phase difference of the co-polarized transmitted electromagnetic wave obtained when a linearly polarized electromagnetic wave is normally incident when the slow axis of the meta-structure in the embodiment of the present invention coincides with the positive direction of the X-axis, varying with the incident wave frequency;

[0036] Figure 7 Schematic diagram of the amplitude of the transmission coefficients of the left-handed circularly polarized transmitted electromagnetic wave and the right-handed circularly polarized transmitted electromagnetic wave obtained when a linearly polarized electromagnetic wave is normally incident when the slow axis of the meta-structure in the embodiment of the present invention forms an angle of ±45° with the positive direction of the X-axis, varying with the incident wave frequency;

[0037] Figure 8 Schematic diagram of the amplitude of the circular cross-polarized transmitted electromagnetic wave obtained when the first orientation angle θ1 in the metasurface unit structure in the embodiment of the present invention is 0° and the second orientation angle θ2 is set to 0°, 30°, 60°, and 90° respectively, varying with the incident wave frequency;

[0038] Figure 9 Schematic diagram of the amplitude of the circular cross-polarized transmitted electromagnetic wave obtained when the orientation angle θ1 of the first meta-structure in the embodiment of the present invention is 0° and incident waves of different frequencies are incident, varying with the relative rotation angle α between the first meta-structure and the second meta-structure;

[0039] Figure 10 Schematic diagram of the phase of the circular cross-polarized transmitted electromagnetic wave obtained when the orientation angle θ1 of the first meta-structure in the embodiment of the present invention is 0° and incident waves of different frequencies are incident, varying with the relative rotation angle α between the first meta-structure and the second meta-structure;

[0040] Figure 11 Schematic diagram of the variation law of the amplitude of the circular cross-polarized transmitted electromagnetic wave in the embodiment of the present invention with the first orientation angle θ1 and the relative rotation angle α between the first meta-structure and the second meta-structure;

[0041] Figure 12 Schematic diagram of the variation law of the phase of the circular cross-polarized transmitted electromagnetic wave in the embodiment of the present invention with the first orientation angle θ1 and the relative rotation angle α between the first meta-structure and the second meta-structure;

[0042] Figure 13Schematic diagram of the electromagnetic wave amplitude distribution corresponding to the transverse double-focus focusing lens according to the embodiment of the present invention;

[0043] Figure 14 Schematic diagram of the electromagnetic wave phase distribution corresponding to the transverse double-focus focusing lens according to the embodiment of the present invention;

[0044] Figure 15 Schematic diagram of the electromagnetic wave amplitude distribution corresponding to the axial double-focus focusing lens according to the embodiment of the present invention;

[0045] Figure 16 Schematic diagram of the electromagnetic wave phase distribution corresponding to the axial double-focus focusing lens according to the embodiment of the present invention;

[0046] Figure 17 Schematic diagram of the test device for testing the double-focus focusing lens according to the embodiment of the present invention;

[0047] Figure 18 Schematic diagram of the electric field intensity distribution diagram of the transverse double-focus focusing lens in the xz plane obtained by simulation according to the embodiment of the present invention;

[0048] Figure 19 Schematic diagram of the electric field intensity distribution diagram of the transverse double-focus focusing lens in the xz plane obtained by experiment according to the embodiment of the present invention;

[0049] Figure 20 Schematic diagram of the electric field intensity distribution diagrams at the two foci of the transverse double-focus focusing lens in the xy plane obtained by simulation according to the embodiment of the present invention;

[0050] Figure 21 Schematic diagram of the electric field intensity distribution diagrams at the two foci of the transverse double-focus focusing lens in the xy plane obtained by experiment according to the embodiment of the present invention;

[0051] Figure 22 Schematic diagram of the change of the electric field intensity of the transverse double-focus focusing lens with the x-axis obtained by simulation and experiment according to the embodiment of the present invention;

[0052] Figure 23 Schematic diagram of the axial electric field intensity distribution diagram of the transverse double-focus focusing lens obtained by simulation according to the embodiment of the present invention;

[0053] Figure 24 Schematic diagram of the axial electric field intensity distribution diagram of the transverse double-focus focusing lens obtained by experiment according to the embodiment of the present invention;

[0054] Figure 25 Schematic diagram of the change of the electric field intensity of the transverse double-focus focusing lens with the z-axis obtained by simulation and experiment according to the embodiment of the present invention;

[0055] Figure 26Schematic diagram of the electric field intensity distribution at the focal point with a focal length of 50 mm in the xy plane of the axially biconical focusing lens obtained by simulation in the embodiment of the present invention;

[0056] Figure 27 Schematic diagram of the electric field intensity distribution at the focal point with a focal length of 50 mm in the xy plane of the axially biconical focusing lens obtained by experiment in the embodiment of the present invention;

[0057] Figure 28 Schematic diagram of the variation of the electric field intensity with the x-axis at the focal point with a focal length of 50 mm of the axially biconical focusing lens obtained by simulation and experiment in the embodiment of the present invention;

[0058] Figure 29 Schematic diagram of the electric field intensity distribution at the focal point with a focal length of 150 mm in the xy plane of the axially biconical focusing lens obtained by simulation in the embodiment of the present invention;

[0059] Figure 30 Schematic diagram of the electric field intensity distribution at the focal point with a focal length of 150 mm in the xy plane of the axially biconical focusing lens obtained by experiment in the embodiment of the present invention;

[0060] Figure 31 Schematic diagram of the variation of the electric field intensity with the x-axis at the focal point with a focal length of 150 mm of the axially biconical focusing lens obtained by simulation and experiment in the embodiment of the present invention.

[0061] Reference numerals:

[0062] 1 - horn antenna; 2 - biconical focusing lens; 3 - probe; 4 - vector network analyzer; 5 - anechoic chamber. Detailed implementation manners

[0063] The following will specifically describe the preferred embodiments of the present invention in conjunction with the drawings. Among them, the drawings form a part of this application and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0064] Embodiment 1

[0065] A specific embodiment of the present invention discloses a method for regulating the amplitude and phase of electromagnetic waves. As Figure 1 shown, it includes the following steps:

[0066] S110. Arrange a plurality of metasurface unit structures in the form of a two-dimensional array; wherein, the metasurface unit structure includes cascaded first meta-structures and second meta-structures with the same structure.

[0067] S120. Adjust the orientation angles of the first meta-structure and the second meta-structure according to the amplitude and phase to be regulated at the position where the meta-surface unit structure is located, so that the difference between the orientation angles of the first meta-structure and the second meta-structure corresponds to the amplitude to be regulated, and the sum of the orientation angles of the first meta-structure and the second meta-structure corresponds to the phase to be regulated.

[0068] To prove the feasibility of the electromagnetic wave amplitude and phase regulation method proposed in the present invention, the principle of its regulation method is described as follows:

[0069] The first meta-structure and the second meta-structure of the present invention can be equivalent to two cascaded equivalent quarter-wave plates (QWPs). By adjusting the orientation angles of the two QWPs, the polarization state evolution path of the circular polarization conversion component on the Poincaré sphere can be changed, and thus independent continuous regulation of the full range of amplitude and phase can be achieved. The theoretical derivation process is as follows:

[0070] Considering the relative rotation between the two quarter-wave plates, when the electromagnetic wave propagates along the z-axis direction, for a quarter-wave plate with its slow axis (the direction of the optical vector with slow propagation speed in the wave plate) in the x direction, its Jones matrix in the circular polarization basis is:

[0071]

[0072] When the quarter-wave plate rotates by an angle θ, the new Jones matrix of the circular polarization basis system can be obtained through the following rotation operation:

[0073]

[0074]

[0075] where R is the rotation matrix.

[0076] As Figure 2 shown, the orientation angles of the two quarter-wave plates are defined as the angles between their slow axes and the x-axis, denoted as θ1 and θ2 respectively. In the figure, S1 and S2 represent the slow axes of the two quarter-wave plates respectively. The Jones matrix corresponding to the unit structure composed of the two cascaded quarter-wave plates is:

[0077]

[0078] α = (θ2 - θ1),

[0079] where α represents the difference between the orientation angles of the two quarter-wave plates, that is, the relative rotation angle of the two quarter-wave plates. The off-diagonal term of the total Jones matrix represents the transmission coefficient of the circular cross-polarized electromagnetic wave, and the corresponding complex amplitude can be expressed as cosα·exp[iσ(α + 2θ1)]. It can be seen from this that the amplitude A and phase corresponding to the transmission coefficient of the circular cross-polarized electromagnetic wave They have the following relationships with the orientation angles of the two quarter-wave plates respectively:

[0080] A = cos(θ2 - θ1),

[0081]

[0082] According to the above two relational expressions, the full-range independent and continuous regulation of the amplitude of the complex amplitude of the electromagnetic wave from 0 to 1 and the phase from 0° to 360° can be realized.

[0083] The above characteristics of the unit structure composed of two quarter-wave plates are generated by the change of the polarization state path brought about by the rotation of the two quarter-wave plates. Exemplarily, after a right-handed circularly polarized incident wave passes through the first quarter-wave plate, it is converted into a linearly polarized wave with an orientation of θ1 + 45°. Since the orientation of the second quarter-wave plate is the θ2 angle, only the linearly polarized wave component with a polarization direction of θ2 + 45° will be converted into a circular polarization state orthogonal to the incident wave. Therefore, based on Malus' law, it can be obtained that the amplitude of the transmitted circularly polarized electromagnetic wave is cosine-related to the relative rotation angle α of the two quarter-wave plates. The regulation mechanism of the phase completely comes from the geometric phase principle and can be vividly represented by the Poincaré sphere. The circular polarization transformation path of the electromagnetic wave is as Figure 3 shown, and the phase change is half of the solid angle of the region enclosed by the two paths.

[0084] From the above analysis, it can be seen that the cascading of two quarter-wave plates can realize the independent and continuous regulation of the amplitude and phase of the incident electromagnetic wave.

[0085] Preferably, as Figure 4 shown, for the metasurface unit structure based on the regulation method proposed in the present invention, it includes a first meta-structure and a second meta-structure. An air layer is provided between the first meta-structure and the second meta-structure. Both the first meta-structure and the second meta-structure can be called meta-structures. As Figure 5 shown, the meta-structure specifically includes a dielectric substrate and two identical circular conductor patches symmetrically attached to both sides of the dielectric substrate; wherein, the dielectric substrate and the two circular conductor patches have the same geometric center; and a C-shaped hole-type resonator ring is provided on the circular conductor patch. Preferably, the material of the circular conductor patch is the corresponding perfect electric conductor in this electromagnetic wave frequency band.

[0086] Exemplarily, in the meta-structure, the thickness of the circular conductor patch is set to 0.018 mm, the radius r1 is 3.5 mm, and the material is copper. The outer radius r2 of the C-shaped hole resonant ring is 3.2 mm, the inner radius r3 is 3 mm, and the corresponding partition width g of the C-shaped hole resonant ring is 0.2 mm. In addition, the material of the dielectric substrate is F4B, its relative permittivity ε is 2.65, the loss tangent is 0.0017, and the thickness d of the dielectric substrate is 1.5 mm. The lattice constant p of the meta-structure is set to 9 mm, which is the side length of the dielectric substrate.

[0087] Based on the above meta-structure, electromagnetic wave amplitude and phase modulation simulation is carried out. As Figure 5 shown, when the incident electromagnetic wave is incident along the z-axis, when the meta-structure is placed in the positive x-axis direction, as Figure 6 shown, when the linearly polarized electromagnetic wave is normally incident, the transmission coefficients T y,y 、T x,x of the co-polarized transmitted electromagnetic wave obtained have amplitudes higher than 0.9, and the phase difference This indicates that the meta-structure is a quarter-wave plate with its slow axis in the direction of its symmetry axis ( Figure 2 in this case, the symmetry axis direction is the X direction). When the symmetry axis (slow axis) of the meta-structure is set to be at 45° with the positive x-axis direction, a right-handed circularly polarized transmitted electromagnetic wave is obtained when the linearly polarized electromagnetic wave is normally incident. When it is at -45°, a left-handed circularly polarized transmitted electromagnetic wave is obtained when the linearly polarized electromagnetic wave is normally incident. As Figure 7 shown, in the application frequency band of 11.9 - 12.6 GHz, the amplitudes of the transmission coefficients T RCP,+45°-LP of the right-handed circularly polarized transmitted electromagnetic wave obtained and the transmission coefficients T LCP,-45°-LP of the left-handed circularly polarized transmitted electromagnetic wave obtained are both higher than 0.9. Therefore, the meta-structure has the properties of a quarter-wave plate.

[0088] Preferably, the above two meta-structures are cascaded, and the thickness of the air layer between the two meta-structures is set to 5 mm to obtain a metasurface unit structure, and simulation is carried out based on this metasurface unit structure.

[0089] As Figure 4 shown, when the slow axes of the first meta-structure and the second meta-structure are rotated counterclockwise along the positive x-axis direction to obtain the corresponding first orientation angle θ1 and second orientation angle θ2 respectively, then α = (θ2 - θ1) is the orientation angle difference between the first meta-structure and the second meta-structure.

[0090] Specifically, when the first orientation angle θ1 is set to 0°, and the second orientation angle θ2 is set to 0°, 30°, 60°, 90° respectively, the curves of the circular cross-polarized transmitted electromagnetic wave amplitude varying with the incident wave frequency obtained are as Figure 8As shown, it can be seen from the figure that in the frequency range of [12 GHz, 13 GHz], when the difference in the orientation angles of the first element structure and the second element structure is 0, the amplitude of the transmission coefficient of the circular cross-polarized transmitted wave obtained correspondingly is the largest. This is because there is no relative rotation between the first element structure and the second element structure, that is, the slow axes are aligned, and the whole is equivalent to a quarter-wave plate. Figure 9 The schematic diagram shows the variation of the amplitude of the circular cross-polarized transmitted electromagnetic wave obtained when the incident wave with different frequencies is incident with the first orientation angle θ1 being 0°, with respect to the relative rotation angle α between the first element structure and the second element structure. It can be seen from the figure that when the incident wave with an interval of 0.1 GHz within the frequency range of [12.1 GHz, 12.5 GHz] is incident, the variation law of the amplitude of the corresponding circular cross-polarized transmitted electromagnetic wave is consistent with the theoretical amplitude variation curve (cosα). Figure 10 The schematic diagram shows the variation of the phase of the circular cross-polarized transmitted electromagnetic wave obtained when the incident wave with different frequencies is incident with the first orientation angle θ1 being 0°, with respect to the relative rotation angle α between the first element structure and the second element structure. It can be seen from the figure that when the incident wave with an interval of 0.1 GHz within the frequency range of [12.1 GHz, 12.5 GHz] is incident, the variation law of the phase of the corresponding circular cross-polarized transmitted electromagnetic wave is consistent with the theoretical phase variation curve (σ(θ1 + θ2)). To better illustrate the feasibility of the amplitude-phase regulation method of the electromagnetic wave proposed by the present invention, Figure 11 、 Figure 12 The variation laws of the amplitude and phase of the circular cross-polarized transmitted electromagnetic wave with respect to the first orientation angle θ1 and the relative rotation angle α between the first element structure and the second element structure are respectively given. It can be seen from the figure that the variation laws of the amplitude and phase with respect to the orientation angle and the rotation angle are consistent with the aforementioned theoretical derivation results.

[0091] In order to achieve the amplitude-phase regulation of the circular cross-polarized electromagnetic wave, a two-dimensional array of multiple metasurface unit structures is arranged, so as to realize the continuous and independent regulation of the amplitude and phase of the electromagnetic wave based on this array.

[0092] Preferably, adjust the orientation angles of the first element structure and the second element structure according to the following corresponding relationship, so that the difference in the orientation angles of the first element structure and the second element structure corresponds to the amplitude to be regulated:

[0093] A = cos(θ2 - θ1)

[0094] Wherein, θ1 represents the orientation angle of the first element structure, θ2 represents the orientation angle of the second element structure, and A represents the amplitude to be regulated.

[0095] Preferably, adjust the orientation angles of the first element structure and the second element structure according to the following corresponding relationship, so that the sum of the orientation angles of the first element structure and the second element structure corresponds to the phase to be regulated:

[0096]

[0097] Among them, when the incident wave is a right-handed circularly polarized electromagnetic wave and the transmitted wave is a left-handed circularly polarized electromagnetic wave, σ = 1; when the incident wave is a left-handed circularly polarized electromagnetic wave and the transmitted wave is a right-handed circularly polarized electromagnetic wave, σ = -1. It represents the phase to be regulated.

[0098] Preferably, the orientation of the C-shaped hole-type resonant ring in each unit structure corresponds to the orientation angle of the unit structure. The orientation of the C-shaped hole-type resonant ring is the direction pointed by the ray where the center of the C-shaped hole-type resonant ring and its partition are located, and it is also the direction of the symmetry axis. Specifically, in the unit structure, the two C-shaped hole-type resonant rings are symmetric with respect to the dielectric substrate, and their symmetry axes are in the same plane and parallel. The direction where the symmetry axis is located is the slow axis direction of the unit structure, that is, the orientation of the orientation angle of the unit structure.

[0099] The orientation of the orientation angle of the unit structure is determined in the following way. Specifically, in the unit structure, the symmetry axes of the two C-shaped hole-type resonant rings are in the same plane and parallel. The direction where the symmetry axis is located is the slow axis direction of the unit structure, that is, the orientation of the orientation angle of the unit structure.

[0100] Preferably, when the orientation angle θ1 of the first unit structure to be adjusted is greater than 0, the symmetry axis of the C-shaped hole-type resonant ring in the first unit structure is rotated counterclockwise by the corresponding angle along the horizontal direction, so that the angle between the symmetry axis and the horizontal direction is the orientation angle θ1 of the first unit structure; if the orientation angle θ1 of the first unit structure to be adjusted is less than 0, the symmetry axis of the C-shaped hole-type resonant ring in the first unit structure is rotated clockwise by the corresponding angle along the horizontal direction, so that the angle between the symmetry axis and the horizontal direction is the orientation angle θ1 of the first unit structure.

[0101] If the orientation angle θ2 of the second unit structure to be adjusted is greater than 0, the symmetry axis of the C-shaped hole-type resonant ring in the second unit structure is rotated counterclockwise by the corresponding angle along the horizontal direction, so that the angle between the symmetry axis and the horizontal direction is the orientation angle θ2 of the second unit structure; if the orientation angle θ2 of the second unit structure to be adjusted is less than 0, the symmetry axis of the C-shaped hole-type resonant ring in the second unit structure is rotated clockwise by the corresponding angle along the horizontal direction, so that the angle between the symmetry axis and the horizontal direction is the orientation angle θ2 of the second unit structure.

[0102] Those skilled in the art can understand that the "rotation" here is only to describe the relationship between the positive and negative of the orientation angle and its orientation, and it does not mean that the C-shaped hole-type resonant ring can rotate on the circular conductor patch. In practical applications, after determining the orientation angle of the unit structure, directly set the angle between the orientation of the C-shaped hole-type resonant ring and the horizontal direction to be the orientation angle.

[0103] Preferably, the thickness of the air layer provided between the first meta-structure and the second meta-structure ranges from [4.75 mm, 5.25 mm]. The thickness of the circular conductor patch ranges from [0.0171 mm, 0.0189 mm], the radius ranges from [3.325 mm, 3.675 mm], the inner radius of the C-shaped hole resonator ring ranges from [2.85 mm, 3.15 mm], the outer radius ranges from [3.04 mm, 3.36 mm], and the corresponding partition width of the C-shaped hole resonator ring ranges from [0.19 mm, 0.21 mm]. In addition, the dielectric substrate is of a square structure, the side length thereof ranges from [8.55 mm, 9.45 mm], the thickness ranges from [1.425 mm, 1.575 mm]. Preferably, the material of the dielectric substrate is F4B, the relative dielectric constant is 2.65, and the tangent value of the loss angle ranges from (0, 0.01]. The meta-surface unit structure within the above parameter ranges can all meet the requirements for the amplitude-phase regulation of electromagnetic waves.

[0104] Embodiment 2

[0105] Arranging multiple meta-surface unit structures in a two-dimensional array can achieve various types of amplitude-phase regulation functions of electromagnetic waves. Preferably, the amplitude-phase regulation method proposed by the present invention can be used for beam generation regulation, holographic imaging regulation, or beam focusing regulation. Exemplarily, a two-dimensional array composed of multiple meta-surface unit structures can achieve the functions of devices such as a dual-focus focusing lens, a multi-beam generator, a Bessel beam generator, and a holographic imaging device.

[0106] Taking the amplitude-phase regulation function of a dual-focus focusing lens as an example, the regulation simulation results are compared with the experimental results to determine the regulation feasibility and regulation accuracy of the amplitude-phase regulation method proposed by the present invention.

[0107] Specifically, the amplitude and phase distributions required for the regulation of the dual-focus focusing lens satisfy the following formula:

[0108]

[0109] where A(x, y) represents the amplitude required for the regulation of the meta-surface unit structure at the position coordinates (x, y), represents the phase required for the regulation of the meta-surface unit structure at the position coordinates (x, y), (x1, y1) and (x2, y2) respectively represent the position coordinates of the two foci of the dual-focus focusing lens, a1 and a2 respectively represent the electric field amplitudes of the two foci, f1 and f2 respectively represent the focal lengths corresponding to the two foci, and λ represents the wavelength of the incident light.

[0110] Based on the settings of the metasurface unit structure parameters in Embodiment 1, when the designed dual-focus focusing lens is a transverse dual-focus focusing lens, for example, the electric field amplitudes of the two foci are set to 0.5 and 0.5 respectively, the corresponding focal lengths are 300 mm and 300 mm respectively, the corresponding focal coordinates are (x1, y1) = (-75 mm, 0 mm) and (x2, y2) = (75 mm, 0 mm), and the incident light wavelength is 12.3 GHz; when the designed dual-focus focusing lens is an axial dual-focus focusing lens, for example, the electric field amplitudes of the two foci are set to 1 and 0.707 respectively, the corresponding focal lengths are 50 mm and 150 mm respectively, the corresponding focal coordinates are (x1, y1) = (0 mm, 0 mm) and (x2, y2) = (0 mm, 0 mm), and the incident light wavelength is 12.3 GHz.

[0111] Taking the transverse dual-focus focusing lens and the axial dual-focus focusing lens as examples respectively, arrange the two-dimensional array of the metasurface unit structures with the parameters set; according to the amplitude and phase distributions to be adjusted required by the transverse dual-focus focusing lens or the axial dual-focus focusing lens, correspondingly adjust the orientation angles of the first meta-structure and the second meta-structure in each metasurface unit structure, so that the orientation angles of the first meta-structure and the second meta-structure in each metasurface unit structure correspond to the amplitude and phase to be adjusted at the position where the metasurface unit structure is located, and perform simulation. The electromagnetic wave amplitude distribution and phase distribution corresponding to the transverse dual-focus focusing lens are respectively as Figure 13 、 14 shown, and the electromagnetic wave amplitude distribution and phase distribution corresponding to the axial dual-focus focusing lens are respectively as Figure 15 、 16 shown.

[0112] Now, use the device shown in Figure 17 to test the transverse dual-focus focusing lens and the axial dual-focus focusing lens to determine whether their focusing effects are consistent with the previously simulated focusing effects.

[0113] Specifically, the horn antenna 1 is used to generate an incident wave. The incident wave is normally incident on the dual-focus focusing lens 2, and the probe 3 is used to collect the transmitted electromagnetic wave and transmit it to the vector network analyzer 4 for analysis. Among them, the horn antenna 1, the dual-focus focusing lens 2 and the probe 3 are all placed in the microwave anechoic chamber 5.

[0114] The simulation results and experimental results are as follows:

[0115] Figure 18 、 Figure 19 respectively show the electric field intensity distribution diagrams of the transverse dual-focus focusing lens in the xz plane obtained by simulation and experiment when the incident wave frequency is 12.3 GHz; Figure 20 、 Figure 21The electric field intensity distribution diagrams at the two foci of the transverse dual-focus focusing lens obtained by simulation and experiment in the xy plane are respectively shown when the incident wave frequency is 12.3 GHz. Figure 22 The schematic diagram of the electric field intensity of the transverse dual-focus focusing lens obtained by simulation and experiment varying with the x-axis is given. Figure 23 、 24 The axial electric field intensity distribution diagrams of the transverse dual-focus focusing lens obtained by simulation and experiment are respectively given. Figure 25 The schematic diagram of the electric field intensity of the transverse dual-focus focusing lens obtained by simulation and experiment varying with the z-axis is given; from Figures 18 to 25 it can be seen that the electric field intensity distributions of the transverse dual-focus focusing lens obtained by simulation and experiment are consistent.

[0116] Figure 26 、 Figure 27 The electric field intensity distribution diagrams at the focus with a focal length of 50 mm in the xy plane of the axial dual-focus focusing lens obtained by simulation and experiment are respectively shown when the incident wave frequency is 12.3 GHz. Figure 28 The schematic diagram of the electric field intensity at the focus with a focal length of 50 mm of the axial dual-focus focusing lens obtained by simulation and experiment varying with the x-axis is given. Figure 29 、 Figure 30 The electric field intensity distribution diagrams at the focus with a focal length of 150 mm in the xy plane of the axial dual-focus focusing lens obtained by simulation and experiment are respectively given. Figure 31 The schematic diagram of the electric field intensity at the focus with a focal length of 150 mm of the axial dual-focus focusing lens obtained by simulation and experiment varying with the x-axis is given; from Figures 26 to 31 it can be seen that the electric field intensity distributions of the axial dual-focus focusing lens obtained by simulation and experiment are consistent.

[0117] The above experimental and simulation results prove that the electromagnetic wave amplitude and phase regulation method proposed based on the present invention has a good amplitude and phase regulation function and can obtain perfect theoretical support.

[0118] Compared with the prior art, the electromagnetic wave amplitude and phase regulation method according to the embodiments of the present invention can, firstly, independently and continuously regulate the amplitude and phase of electromagnetic waves by setting the orientation angles of two meta-structures in the metasurface unit structure, without changing the size of the unit structure. The regulation method is flexible, with high regulation efficiency, and can achieve full-range regulation of the amplitude of electromagnetic waves in the range of [0, 1] and full-range regulation of the phase of electromagnetic waves in the range of [0°, 360°]. Secondly, the electromagnetic wave amplitude and phase regulation method proposed by the present invention uses the metasurface unit structure based on the wave plate theory and the PB phase theory to regulate the amplitude and phase of electromagnetic waves, with perfect theoretical support, and does not rely on regulating the amplitude and phase of electromagnetic waves irregularly by changing structural parameters. Based on this regulation method, the amplitude and phase regulation requirements of various regulation devices can be met, such as dual-focus focusing lenses, multi-beam generators, Bessel beam generators, and holographic imaging devices, etc. This regulation method has strong applicability and a wide range of application scenarios. By changing the electrical size of the metasurface unit structure to match the materials of the corresponding circular conductor patch and dielectric, electromagnetic wave amplitude and phase regulation in multiple frequency bands such as the microwave band, infrared band, terahertz band, and optical frequency band can be achieved. In addition, for the electromagnetic wave amplitude and phase regulation method proposed by the present invention, the structural sizes of the metasurface unit structures used are all the same, only the orientation angles of the two meta-structures are different, which simplifies the manufacturing process of the two-dimensional array and greatly reduces the manufacturing cost.

[0119] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. An electromagnetic wave amplitude and phase regulation method, characterized in that, It includes the following steps: Arrange a plurality of metasurface unit structures in the form of a two-dimensional array; the metasurface unit structure includes cascaded first and second meta-structures with the same structure; Adjust the orientation angles of the first and second meta-structures according to the amplitude and phase to be adjusted at the position where the metasurface unit structure is located, so that the difference between the orientation angles of the first and second meta-structures corresponds to the amplitude to be adjusted, and the sum of the orientation angles of the first and second meta-structures corresponds to the phase to be adjusted; Both the first and second meta-structures include a dielectric substrate and two identical circular conductor patches symmetrically attached to both sides of the dielectric substrate; the dielectric substrate and the two circular conductor patches have the same geometric center; and, a C-shaped hole resonator ring is arranged on the circular conductor patch, and the material of the circular conductor patch is the corresponding perfect electric conductor in this electromagnetic wave frequency band; An air layer is arranged between the first and second meta-structures.

2. The electromagnetic wave amplitude and phase regulation method according to claim 1, characterized in that Adjust the orientation angles of the first and second meta-structures according to the following corresponding relationship, so that the difference between the orientation angles of the first and second meta-structures corresponds to the amplitude to be adjusted: A = cos(θ2 - θ1) where θ1 represents the orientation angle of the first meta-structure, θ2 represents the orientation angle of the second meta-structure, and A represents the amplitude to be adjusted.

3. The electromagnetic wave amplitude and phase regulation method according to claim 1 or 2, characterized in that Adjust the orientation angles of the first and second meta-structures according to the following corresponding relationship, so that the sum of the orientation angles of the first and second meta-structures corresponds to the phase to be adjusted: Among them, when the incident wave is a right-handed circularly polarized electromagnetic wave and the transmitted wave is a left-handed circularly polarized electromagnetic wave, σ = 1; when the incident wave is a left-handed circularly polarized electromagnetic wave and the transmitted wave is a right-handed circularly polarized electromagnetic wave, σ = -1. It represents the phase to be regulated as required.

4. The electromagnetic wave amplitude and phase regulation method according to claim 3, wherein When the orientation angle θ1 of the first meta-structure to be adjusted is greater than 0, rotate the symmetry axis of the C-shaped hole resonator ring in the first meta-structure counterclockwise by the corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ1 of the first meta-structure; If the orientation angle θ1 of the first meta-structure to be adjusted is less than 0, rotate the symmetry axis of the C-shaped hole resonator ring in the first meta-structure clockwise by the corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ1 of the first meta-structure; If the orientation angle θ2 of the second meta-structure to be adjusted is greater than 0, rotate the symmetry axis of the C-shaped hole resonator ring in the second meta-structure counterclockwise by the corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ2 of the second meta-structure; if the orientation angle θ2 of the second meta-structure to be adjusted is less than 0, rotate the symmetry axis of the C-shaped hole resonator ring in the second meta-structure clockwise by the corresponding angle along the horizontal direction, so that the included angle between the symmetry axis and the horizontal direction is the orientation angle θ2 of the second meta-structure.

5. The electromagnetic wave amplitude and phase regulation method according to claim 1, wherein The value range of the thickness of the air layer between the first and second meta-structures is [4.75 mm, 5.25 mm].

6. The electromagnetic wave amplitude and phase regulation method according to claim 1, wherein The thickness of the circular conductor patch ranges from [0.0171 mm, 0.0189 mm], the radius ranges from [3.325 mm, 3.675 mm], the inner radius of the C-shaped hole resonator ring ranges from [2.85 mm, 3.15 mm], the outer radius ranges from [3.04 mm, 3.36 mm], and the corresponding partition width of the C-shaped hole resonator ring ranges from [0.19 mm, 0.21 mm].

7. The electromagnetic wave amplitude and phase regulation method according to claim 1, characterized in that The dielectric substrate is of a square structure, and the thickness thereof ranges from [1.425 mm, 1.575 mm].

8. The electromagnetic wave amplitude and phase regulation method according to claim 1, wherein The electromagnetic wave amplitude and phase regulation method can be used for beam generation regulation, holographic imaging regulation, or beam focusing regulation.

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