An orbital angular momentum vortex electromagnetic wave multiplexing device

Abstract

The present invention relates to an orbital angular momentum vortex electromagnetic wave multiplexing device, belonging to the technical field of orbital angular momentum electromagnetic wave regulation, and comprising a plurality of angular domain dispersion units arranged uniformly in an array; each angular domain dispersion unit includes: an ELC resonator patch layer, a JC resonator patch layer, and a dielectric substrate layer; the arm length parameters of each ELC resonator patch layer and JC resonator patch layer are determined by the phase response required for the angular domain dispersion unit to ensure the output of an OAM beam and perpendicular emission. Since the present invention respectively selects appropriate unit structure sizes according to the phase responses required by the angular domain dispersion units at different positions of the metasurface and arranges them to form an angular domain dispersion metasurface, so that it can have a specific phase response distribution required for generating different mode OAM vortex waves and perpendicular emission for electromagnetic waves incident at different angles, thus generating approximately single-mode OAM perpendicular transmission beams at each incident angle respectively, thereby effectively improving the mode conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of orbital angular momentum electromagnetic wave regulation, and particularly to an orbital angular momentum vortex electromagnetic wave multiplexing device based on an angular domain dispersion metasurface. Background Technique

[0002] In recent years, with the development of communication technologies, spectrum resources have become more scarce. Vortex electromagnetic waves carrying orbital angular momentum (OAM) have attracted more attention due to their potential in communication. Different from traditional plane waves, the wavefront phase of an OAM beam is helically distributed, and the phase distribution range is 2πl, where l is the OAM mode number (l is a positive or negative integer). OAM beams with different mode numbers are orthogonal to each other. When modulated signals are loaded onto beams with different mode numbers, the signal channels do not interfere with each other, which can effectively improve the transmission performance.

[0003] OAM multiplexing is to convert multiple beams carrying independent information into orthogonal OAM beams with different modes and emit them in the same direction. In recent years, OAM multiplexing metasurfaces for electromagnetic waves incident from multiple directions have been realized. These metasurfaces usually linearly superimpose the phase responses required to generate multiple OAM beams, or stagger or randomly arrange the metasurface units with the phase responses required to generate OAM beams, so as to realize the multiplexing of OAM beams with different modes in a specific emission direction.

[0004] However, for electromagnetic waves incident from each direction, the above metasurfaces can only convert a part of the electromagnetic energy into electromagnetic waves carrying the required OAM mode and emit them in the same direction, and the remaining energy will be converted into electromagnetic waves carrying other parasitic OAM modes and emitted in other directions. This design mode conversion efficiency is relatively low. Summary of the Invention

[0005] The object of the present invention is to provide an orbital angular momentum vortex electromagnetic wave multiplexing device, which can generate approximately single-mode OAM vertically transmitted beams at each incident angle. Compared with the existing OAM multiplexing metasurfaces, it has a higher mode conversion efficiency and solves the problem of low conversion efficiency in the prior art.

[0006] To achieve the above object, the present invention provides the following solution:

[0007] An orbital angular momentum vortex electromagnetic wave multiplexing device, comprising: a plurality of angular domain dispersion units;

[0008] The angular domain dispersion units are arranged in an array uniformly to form an angular domain dispersion metasurface;

[0009] The angular dispersion unit includes: an ELC resonator patch layer, a JC resonator patch layer, and a dielectric substrate layer; the dielectric substrate layer is disposed between the ELC resonator patch layer and the JC resonator patch layer;

[0010] The arm length parameters of each of the ELC resonator patch layer and the JC resonator patch layer are determined by the required phase response; the required phase response is the phase response required for each angular dispersion unit to ensure the output of an OAM beam and vertical emission.

[0011] In some embodiments,

[0012] The phase response required for each angular dispersion unit to ensure the output of an OAM beam and vertical emission is determined according to the formula Φ1 = l·tan -1 (y i / x i ) + Φ0 and the formula ; where, Φ1 represents the phase response required to achieve an l-order OAM beam, (x i , y i ) represents the coordinates of the angular dispersion unit in the angular dispersion metasurface, Φ0 represents the phase response at the center of the angular dispersion metasurface, θ i represents the incident angle of the plane electromagnetic wave, and Φ2 represents the phase response required for the angular dispersion unit at vertical emission;

[0013] When ensuring the vertical emission of the output OAM beam, the phase response required for each angular dispersion unit is Φ, and Φ = Φ1 + Φ2.

[0014] In some embodiments, the correspondence between the arm length parameters of each patch in the ELC resonator patch layer and the JC resonator patch layer and the phase response required for the angular dispersion unit is as follows:

[0015] When L1 is from 4.01 mm to 2.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 is from 1.47 mm to 1.56 mm, and C1 is from 0.96 mm to 1.03 mm, a phase response change from -250° to -210° can be achieved for an incident electromagnetic wave of -45°, and at the same time, a phase response change from 110° to 70° can be achieved for an incident electromagnetic wave of 45°; where, L1 and L2 represent the lengths of the two large arms of the JC resonator patch layer, L3 and L4 represent the lengths of the two small arms of the JC resonator patch layer, and C1 represents the length of the large arm of the ELC resonator patch layer;

[0016] When L1 is 0.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, and L4 ranges from 1.53 mm to 0.55 mm, and C1 ranges from 1.09 mm to 2.86 mm, it is possible to achieve a phase response change of -200° to -110° for an incident electromagnetic wave at -45°, and at the same time, achieve a phase response change of 60° to -30° for an incident electromagnetic wave at 45°;

[0017] When L1 ranges from 2.55 mm to 4.08 mm, L2 ranges from 5.61 mm to 4.08 mm, L3 and L4 are both 1 mm, and C1 ranges from 3.2 mm to 4.8 mm, it is possible to achieve a phase response change of -100° to -70° for an incident electromagnetic wave at -45°, and at the same time, achieve a phase response change of -40° to -70° for an incident electromagnetic wave at 45°;

[0018] When L1 ranges from 4.08 mm to 5.61 mm, L2 ranges from 4.08 mm to 2.55 mm, L3 and L4 are both 1 mm, and C1 ranges from 4.8 mm to 3.2 mm, it is possible to achieve a phase response change of -70° to -40° for an incident electromagnetic wave at -45°, and at the same time, achieve a phase response change of -70° to -100° for an incident electromagnetic wave at 45°;

[0019] When L1 is 6.5 mm, L2 is 0.5 mm, L3 ranges from 0.55 mm to 1.53 mm, L4 is 0.2 mm, and C1 ranges from 2.86 mm to 1.09 mm, it is possible to achieve a phase response change of -30° to 60° for an incident electromagnetic wave at -45°, and at the same time, achieve a phase response change of -110° to -200° for an incident electromagnetic wave at 45°;

[0020] When L1 is 6.5 mm, L2 ranges from 2.5 mm to 4.01 mm, L3 ranges from 1.56 mm to 1.47 mm, L4 is 0.2 mm, and C1 ranges from 1.03 mm to 0.96 mm, it is possible to achieve a phase response change of 70° to 110° for an incident electromagnetic wave at -45°, and at the same time, achieve a phase response change of -210° to -250° for an incident electromagnetic wave at 45°.

[0021] In some embodiments,

[0022] The ELC resonator patch layer is composed of two completely symmetric "T"-shaped metal patches. Among them, the arm length of the vertical patch is C1, the width of the metal patch is 0.2 mm, and the middle interval between the two "T"-shaped metal patches is 0.2 mm;

[0023] The relative dielectric constant of the dielectric substrate layer is 10.2, and the thickness is 0.635 mm.

[0024] In some embodiments,

[0025] The JC resonator patch layer has a straight-arm structure;

[0026] The straight-arm structure is composed of two "I"-shaped patches, and the two "I"-shaped patches are vertically crossed and rotated by 45° at the center.

[0027] In some embodiments,

[0028] The JC resonator patch layer has an arrowhead structure;

[0029] The arrowhead structure is composed of a bidirectional arrowhead-shaped patch and a straight-line patch, and the bidirectional arrowhead-shaped patch and the straight-line patch are vertically crossed and rotated by 45° at the center.

[0030] In some embodiments, the metal patches of the JC resonator patch layer are inclined by 45° along the normal direction of the angular dispersion metasurface.

[0031] In some embodiments, the size of the angular dispersion unit is 5mm * 5mm * 3.5mm.

[0032] In some embodiments, the operating frequency of the angular dispersion metasurface is 10 GHz.

[0033] In some embodiments, the number of the angular dispersion units is 26 * 18.

[0034] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention:

[0035] The present invention provides an orbital angular momentum vortex electromagnetic wave multiplexing device, which includes a plurality of angular dispersion units arranged in an array in a uniform manner; each angular dispersion unit includes: an ELC resonator patch layer, a JC resonator patch layer, and a dielectric substrate layer; the dielectric substrate layer is disposed between the ELC resonator patch layer and the JC resonator patch layer; the arm length parameters of each of the ELC resonator patch layer and the JC resonator patch layer are determined by the phase response required for the angular dispersion unit to ensure the output of the OAM beam and perpendicular emission. The present invention can have a specific phase response distribution required for generating different-mode OAM vortex waves and perpendicular emission for electromagnetic waves incident at different angles. Since the present invention selects appropriate unit structure sizes according to the phase response required for the angular dispersion unit at different positions of the angular dispersion metasurface to ensure the output of the OAM beam and perpendicular emission during the manufacturing process, and forms the angular dispersion metasurface through an array arrangement, thus generating an approximately single-mode OAM vertically transmitted beam at each incident angle, thereby effectively improving the mode conversion efficiency. Description of the Drawings

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0037] Figure 1 Schematic diagram of the overall structure of the angular dispersion unit provided in the first embodiment of the present invention.

[0038] Figure 2 Schematic diagram of the patch structure of the angular dispersion unit provided in the first embodiment of the present invention.

[0039] Figure 3 Structure parameter diagram of each angular dispersion unit provided in the first embodiment of the present invention.

[0040] Figure 4 Distribution diagrams of the transmission phase and transmission amplitude of each angular dispersion unit provided in the first embodiment of the present invention under the incidence of plane electromagnetic waves at ±45° with a frequency of 10 GHz.

[0041] Figure 5 Distribution diagram of the required phase response at each position of the angular dispersion metasurface provided in the first embodiment of the present invention.

[0042] Figure 6 Distribution diagrams of the phase and field strength of the transmitted electromagnetic wave obtained by simulation under the incidence of a plane electromagnetic wave at -45° with a frequency of 10 GHz provided in the first embodiment of the present invention.

[0043] Figure 7 Distribution diagrams of the phase and field strength of the transmitted electromagnetic wave obtained by simulation under the incidence of a plane electromagnetic wave at 45° with a frequency of 10 GHz provided in the first embodiment of the present invention.

[0044] Figure 8 Distribution diagrams of the phase and field strength of the transmitted electromagnetic wave obtained by simulation under the incidence of a plane electromagnetic wave at 0° with a frequency of 10 GHz provided in the first embodiment of the present invention.

[0045] Figure 9 OAM mode purity spectrum diagram of the transmitted wave generated when a plane electromagnetic wave with a frequency of 10 GHz is incident along -45° provided in the first embodiment of the present invention.

[0046] Figure 10 OAM mode purity spectrum diagram of the transmitted wave generated when a plane electromagnetic wave with a frequency of 10 GHz is incident along +45° provided in the first embodiment of the present invention.

[0047] Figure 11It is the OAM mode purity spectrum diagram of the transmitted wave generated when the plane electromagnetic wave with a frequency of 10 GHz in the first embodiment of the present invention is incident at 0°.

[0048] Figure 12 It is a schematic diagram of the principle of the orbital angular momentum vortex electromagnetic wave multiplexing device provided in the first embodiment of the present invention.

[0049] Figure 13 It is a schematic diagram of the principle of the angular domain dispersion metasurface provided in the second embodiment of the present invention.

[0050] Figure 14 It is the phase response distribution diagram required at each position of the angular domain dispersion metasurface provided in the second embodiment of the present invention.

[0051] Figure 15 It is the phase distribution diagram and field strength distribution diagram of the transmitted electromagnetic wave obtained by simulation under the condition that the plane electromagnetic wave with a frequency of 10 GHz is incident at -45° in the second embodiment of the present invention.

[0052] Figure 16 It is the phase distribution diagram and field strength distribution diagram of the transmitted electromagnetic wave obtained by simulation under the condition that the plane electromagnetic wave with a frequency of 10 GHz is incident at 45° in the second embodiment of the present invention.

[0053] Figure 17 It is the phase distribution diagram and field strength distribution diagram of the transmitted electromagnetic wave obtained by simulation under the condition that the plane electromagnetic wave with a frequency of 10 GHz is incident at 0° in the second embodiment of the present invention.

[0054] Figure 18 It is the OAM mode purity spectrum diagram of the transmitted wave generated when the plane electromagnetic wave with a frequency of 10 GHz is incident at -45° in the second embodiment of the present invention.

[0055] Figure 19 It is the OAM mode purity spectrum diagram of the transmitted wave generated when the plane electromagnetic wave with a frequency of 10 GHz is incident at +45° in the second embodiment of the present invention.

[0056] Figure 20 It is the OAM mode purity spectrum diagram of the transmitted wave generated when the plane electromagnetic wave with a frequency of 10 GHz is incident at 0° in the second embodiment of the present invention. Detailed implementation manners

[0057] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0058] The object of the present invention is to provide an orbital angular momentum vortex electromagnetic wave multiplexing device, which has the function of generating a specific phase response distribution required for generating different OAM mode vortex waves for electromagnetic waves incident at different angles. By using this function, an approximately single-mode OAM vertically transmitted beam can be generated at each incident angle. Compared with the existing OAM multiplexing metasurface, it has a higher mode conversion efficiency and solves the problem of low conversion efficiency in the prior art.

[0059] The present invention discloses an orbital angular momentum (OAM) vortex electromagnetic wave multiplexing device based on an angular dispersion metasurface, which mainly solves the problem that the prior art cannot efficiently generate different orbital angular momentum vortex beams with the same outgoing direction for plane electromagnetic waves incident from multiple directions. The device is a metasurface, and the metasurface is composed of a plurality of basic units with similar structural dimensions. Each unit consists of three layers, namely two metal patch layers and a dielectric substrate, and the dielectric substrate is arranged between the two metal patch layers; a number of units are arranged according to a certain phase response distribution rule to form an angular dispersion metasurface. The angular dispersion metasurface described in the present invention can generate different mode OAM vortex waves transmitted vertically along the metasurface for plane electromagnetic waves incident from three different directions (0°, +45°, -45°). When the electromagnetic wave is obliquely incident at θ i =-45°, a vortex wave with an OAM mode number of l (l = 1, 2...) is generated; when the electromagnetic wave θ i = 45° is obliquely incident, a vortex wave with an OAM mode number of -l is generated; when the electromagnetic wave is vertically incident at θ i = 0°, a vortex wave with an OAM mode number of 0 is generated. The above angular dispersion metasurface has a specific phase response distribution required for generating different OAM mode vortex waves and vertically outgoing for electromagnetic waves incident at different angles, so an approximately single-mode OAM vertically transmitted beam is generated at each incident angle. Compared with the existing OAM multiplexing metasurface, it has a higher mode conversion efficiency.

[0060] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0061] Example 1:

[0062] This embodiment provides an orbital angular momentum vortex electromagnetic wave multiplexing device, including: a number of angular dispersion units.

[0063] The angular dispersion units are arranged in an array in a uniform manner to form an angular dispersion metasurface.

[0064] The angular dispersion unit includes: an ELC resonator patch layer, a JC resonator patch layer, and a dielectric substrate layer; the dielectric substrate layer is disposed between the ELC resonator patch layer and the JC resonator patch layer, and the ELC resonator patch layer and the JC resonator patch layer are attached to the front and outer surfaces of the dielectric substrate. Please refer to Figure 1 . In this embodiment, the dimensions of the angular dispersion unit are all 5mm * 5mm * 3.5mm.

[0065] As Figure 2 shown, in this embodiment, the ELC resonator patch layer is an Electric field coupled (ELC) resonator patch; the JC resonator patch layer is a Jerusalem cross (JC) resonator patch. The two metal patches are arranged in parallel on the front and back sides of the dielectric substrate layer, and the JC resonator patch is inclined 45° along the normal direction of the metasurface.

[0066] As Figure 2 shown in Fig. a, the ELC resonator patch layer is composed of two completely symmetric "T"-shaped metal patches. Among them, the arm length of the vertical patch is C1, the width of the metal patch is 0.2mm, and the middle interval between the two "T"-shaped metal patches is 0.2mm.

[0067] In this embodiment, the JC resonator patch layer is of a straight-arm type structure or an arrow type structure, and the patch width is 0.2mm.

[0068] As Figure 2 shown in Fig. b, the straight-arm type structure is composed of two "I"-shaped patches, and the two "I"-shaped patches are vertically crossed and rotated 45° at the center, and the arm lengths of each patch are L1, L2, L3, and L4 respectively. As Figure 2 shown in Fig. c, the arrow type structure is similar to the straight-arm type structure, the arrow arm length is L1, and the remaining arm lengths are L2, L3, and L4. The arrow type structure is composed of a two-way arrow-shaped patch and a straight-line patch, and the two-way arrow-shaped patch and the straight-line patch are vertically crossed and rotated 45° at the center.

[0069] The materials of the ELC resonator patch layer and the JC resonator patch layer are copper, and the material of the dielectric substrate layer is Rogers RT6010 / 6010LM, with a relative dielectric constant of 10.2 and a thickness of 0.635mm.

[0070] The arm length parameters of each of the ELC resonator patch layers and the JC resonator patch layers are determined by the required phase response; the required phase response is the phase response required for each angular domain dispersion unit to ensure the output of an OAM beam and vertical emission. In other words, a number of angular domain dispersion units are arranged according to a certain phase response distribution rule to form an angular domain dispersion metasurface.

[0071] The required phase response of each angular domain dispersion unit is determined according to the formula Φ1 = l·tan -1 (y i / x i ) + Φ0 and the formula ; where, Φ1 represents the phase response required to achieve an l-th order OAM beam, (x i , y i ) represents the coordinates of the angular domain dispersion unit in the angular domain dispersion metasurface, Φ0 represents the phase response of the angular domain dispersion unit at the coordinates (0, 0), θ i represents the incident angle of the plane electromagnetic wave, and Φ2 represents the phase response required for the angular domain dispersion unit during vertical emission.

[0072] When ensuring that the output wave is vertically emitted, the required phase response of each angular domain dispersion unit is Φ, and Φ = Φ1 + Φ2.

[0073] Specifically, in this embodiment, the center of the angular domain dispersion metasurface is the origin, and the coordinates of the centers of other angular domain dispersion units relative to the origin are (x i , y i ), and the phase response Φ1 required to achieve an l-th order OAM beam:

[0074] Φ1 = l·tan -1 (y i / x i ) + Φ0

[0075] where l = 0, ±1, ±2..., and Φ0 is the phase response of the angular domain dispersion unit at the coordinates (0, 0).

[0076] The plane electromagnetic wave with an incident angle of θ i passes through the angular domain dispersion metasurface and is vertically emitted, satisfying the generalized Snell's law:

[0077]

[0078] where, λ0 is the vacuum wavelength, dx is the distance between adjacent angular domain dispersion units, and dΦ is the phase difference between adjacent angular domain dispersion units.

[0079] According to the generalized Snell's law, the phase response Φ2 of each angular domain dispersion unit during vertical emission needs to satisfy:

[0080]

[0081] Let Φ0 = 0, where θ i = 0°, ±45°.

[0082] To achieve the vertical emission of the OAM beam, the total phase response Φ required for the angular dispersion unit at the coordinate (x i , y i ) should satisfy: Φ = Φ1 + Φ2.

[0083] To ensure the generation of vortex waves with OAM mode numbers of 0, -1, and +1 and their vertical emission along the normal direction of the metasurface, when fabricating each angular dispersion unit, its required phase response should be determined according to the above formula based on its position, and then the arm length parameter should be determined according to the relationship between the phase response and the arm length parameter.

[0084] Please refer to Figure 3 and Figure 4 , the corresponding relationship between the arm length parameters of each patch in each of the ELC resonator patch layer and the JC resonator patch layer and the phase response required for the angular dispersion unit is:

[0085] When L1 ranges from 4.01 mm to 2.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 ranges from 1.47 mm to 1.56 mm, and C1 ranges from 0.96 mm to 1.03 mm, it can achieve a phase response change from -250° to -210° for -45° incident electromagnetic waves, and at the same time achieve a phase response change from 110° to 70° for 45° incident electromagnetic waves, corresponding to angular dispersion units 1 - 5; (the phase responses of all units to 0° incident electromagnetic waves hardly change, and it can exactly achieve the l = 0 mode emission for 0° incident electromagnetic waves, so it is not elaborated here). Among them, L1 and L2 represent the lengths of the two large arms of the JC resonator patch layer, L3 and L4 represent the lengths of the two small arms of the JC resonator patch layer, and C1 represents the length of the large arm of the ELC resonator patch layer.

[0086] When L1 is 0.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 ranges from 1.53 mm to 0.55 mm, and C1 ranges from 1.09 mm to 2.86 mm, it can achieve a phase response change from -200° to -110° for -45° incident electromagnetic waves, and at the same time achieve a phase response change from 60° to -30° for 45° incident electromagnetic waves, corresponding to angular dispersion units 6 - 15.

[0087] When L1 ranges from 2.55 mm to 4.08 mm, L2 ranges from 5.61 mm to 4.08 mm, both L3 and L4 are 1 mm, and C1 ranges from 3.2 mm to 4.8 mm, it is possible to achieve a phase response change from -100° to -70° for an incident electromagnetic wave at -45°, and at the same time achieve a phase response change from -40° to -70° for an incident electromagnetic wave at 45°, corresponding to the angular dispersion units 16 - 19.

[0088] When L1 ranges from 4.08 mm to 5.61 mm, L2 ranges from 4.08 mm to 2.55 mm, both L3 and L4 are 1 mm, and C1 ranges from 4.8 mm to 3.2 mm, it is possible to achieve a phase response change from -70° to -40° for an incident electromagnetic wave at -45°, and at the same time achieve a phase response change from -70° to -100° for an incident electromagnetic wave at 45°, corresponding to the angular dispersion units 19 - 22.

[0089] When L1 is 6.5 mm, L2 is 0.5 mm, L3 ranges from 0.55 mm to 1.53 mm, L4 is 0.2 mm, and C1 ranges from 2.86 mm to 1.09 mm, it is possible to achieve a phase response change from -30° to 60° for an incident electromagnetic wave at -45°, and at the same time achieve a phase response change from -110° to -200° for an incident electromagnetic wave at 45°, corresponding to the angular dispersion units 23 - 32.

[0090] When L1 is 6.5 mm, L2 ranges from 2.5 mm to 4.01 mm, L3 ranges from 1.56 mm to 1.47 mm, L4 is 0.2 mm, and C1 ranges from 1.03 mm to 0.96 mm, it is possible to achieve a phase response change from 70° to 110° for an incident electromagnetic wave at -45°, and at the same time achieve a phase response change from -210° to -250° for an incident electromagnetic wave at 45°, corresponding to the angular dispersion units 33 - 37.

[0091] Among them, the ELC resonator patch layer of the angular dispersion units 1 - 15 and 23 - 37 is in an arrow - shaped structure, and the ELC resonator patch layer of the angular dispersion units 16 - 22 is in a straight - arm - shaped structure.

[0092] As Figure 4 shown, at the operating frequency of 10 GHz, when using a plane electromagnetic wave for incidence, the angular dispersion units have different phase responses at different incident angles. The phase response of the designed angular dispersion units has the characteristic of angle sensitivity. The angular dispersion units 1 - 37 have linearly varying phase responses at 45° and -45° incidences respectively, and the phase response change can cover -250° to 110°.

[0093] In this embodiment, the number of angular dispersion units is 26 * 18, and the size of the angular dispersion metasurface is 91 mm * 90 mm.

[0094] AsFigure 5 As shown Figure 5 is the phase response distribution diagram required at each position of this embodiment, where Figure 5 a is the phase response required for each unit when vertically emitting; Figure 5 b is the phase response required to achieve ±1-order OAM beams; Figure 5 c is the total phase response required for the unit.

[0095] The effect of this embodiment can be further illustrated by the following simulation diagrams:

[0096] Figures 6 - 8 are the phase distribution diagram and field strength distribution diagram of the transmitted electromagnetic wave obtained by simulation of this embodiment, and its operating frequency is 10 GHz. Please refer to Figure 6 , when the incident angle is -45°, a vortex wave with a mode number of 1 is generated and vertically emitted; please refer to Figure 7 , when the incident angle is 45°, a vortex wave with a mode number of -1 is generated and vertically emitted; please refer to Figure 8 , when the incident angle is 0°, an electromagnetic wave with a mode number of 0 is generated and vertically emitted.

[0097] As Figures 9 - 11 shown, in the distribution diagram Figures 6 - 8 shown, with the center point as the center of the circle, sampling rings are determined by selecting appropriate radii respectively. The field strength and phase distributions on the ring are sampled to obtain their electric field strength and phase values, and sampled at equal interval angles. The electric field value data on the circumference is selected for Fourier transform to obtain the ratio of the OAM beams with each mode number from -10 to 10, so as to obtain the OAM spectrum diagram.

[0098] It can be seen from the OAM purity spectrum diagram that at the incident angle θ i =-45°, the energy proportion of the OAM beam with a mode number of 1 is the highest; at the incident angle θ i =45°, the energy proportion of the OAM beam with a mode number of -1 is the highest; at the incident angle θ i =0°, the energy proportion of the OAM beam with a mode number of 0 is the highest. Therefore, the metasurface can generate high-purity OAM beams under the incidence of plane electromagnetic waves in three different directions.

[0099] Please refer to Figure 12 , the angular dispersion metasurface provided by this embodiment can generate different mode OAM vortex waves transmitted along the vertical direction of the metasurface for plane electromagnetic waves incident in three different directions (0°, +45°, -45°). When the electromagnetic wave is obliquely incident along θ i =-45°, a vortex wave with an OAM mode number of l (l = 1, 2...) is generated; when the electromagnetic wave θ i =45° is obliquely incident, a vortex wave with an OAM mode number of -l is generated; when the electromagnetic wave is along θ iWhen the incident angle is 0°, a vortex wave with an OAM mode number of 0 is generated. Thus, OAM vortex wave multiplexing under three incident angles is achieved, which can be used in multiple fields such as wireless communication, radar imaging, and target detection. The above angular dispersion metasurface has a specific phase response distribution required to generate OAM vortex waves with different modes for electromagnetic waves incident at different angles, so an approximately single-mode OAM vertically transmitted beam is generated at each incident angle. Compared with the existing OAM multiplexing devices based on metasurfaces, it has a higher mode conversion efficiency.

[0100] Embodiment 2:

[0101] This embodiment provides an orbital angular momentum vortex electromagnetic wave multiplexing device. The orbital angular momentum vortex electromagnetic wave multiplexing device is an angular dispersion metasurface with a working frequency of 10 GHz. The units constituting the angular dispersion metasurface are the same as those in Embodiment 1, but due to different required phase responses, the unit arrangements of the two embodiments are different. The number of units in this embodiment is 26*18, and the size of the metasurface is 91mm*90mm.

[0102] As Figure 13 shown, when plane electromagnetic waves are incident on the angular dispersion metasurface provided in Embodiment 2 of the present invention at 0°, +45°, and -45°, vortex waves with OAM mode numbers of 0, -2, and +2 can be generated and vertically exit along the normal direction of the metasurface.

[0103] Figure 14 is the phase response distribution diagram required at each position in this embodiment, where Figure 14 a is the phase response required for each unit when vertically exiting; Figure 14 b is the phase response required to achieve ±2-order OAM beams; Figure 14 c is the total phase response required for the unit.

[0104] Figures 15 - 17 are the phase distribution diagram and field strength distribution diagram of the transmitted electromagnetic wave obtained by simulation in this embodiment; its working frequency is 10 GHz. When the incident angle is -45°, a vortex wave with a mode number of 2 is generated and vertically exits. When the incident angle is 45°, a vortex wave with a mode number of -2 is generated and vertically exits. When the incident angle is 0°, an electromagnetic wave with a mode number of 0 is generated and vertically exits.

[0105] Figures 18 - 20 is the OAM purity spectrum diagram obtained by the same method as in Figures 9 - 11 Embodiment 1. It can be seen from the OAM purity spectrum diagram that at the incident angle θ i =-45°, the energy proportion of the mode number 2 is the highest; at the incident angle θ i =45°, the energy proportion of the mode number -2 is the highest; at the incident angle θ i= 0°, the energy with a mode number of 0 has the highest proportion. Therefore, the metasurface can generate a high-purity OAM beam under a symmetric beam.

[0106] Embodiment 3:

[0107] This embodiment provides an orbital angular momentum vortex electromagnetic wave multiplexing device based on an angular domain dispersion metasurface and a manufacturing method thereof. When a plane electromagnetic wave is incident at 0°, +45°, and -45°, the device generates vortex electromagnetic waves with orbital angular momentum mode numbers of 0, -l, and l respectively and vertically emits them.

[0108] The device is an angular domain dispersion metasurface for generating orbital angular momentum vortex electromagnetic waves, including a number of angular domain dispersion units; according to the phase responses required at different positions of the angular domain dispersion metasurface, different angular domain dispersion units are selected and arranged in an array in a uniform manner to form the angular domain dispersion metasurface.

[0109] The angular domain dispersion unit consists of three layers, namely two metal pattern layers and one dielectric substrate, and the dielectric substrate is arranged between the two metal pattern layers. The metal pattern layer is an ELC resonator patch and a JC resonator patch.

[0110] Furthermore, in order to achieve 360° phase shift, the structure of the JC resonator patch is divided into two types, that is, L3 is divided into a straight-arm type and an arrow type.

[0111] The JC resonator patch has unequal arm lengths and is inclined 45° along the direction perpendicular to the incident electromagnetic wave (the incident angle θ i = 0°).

[0112] The arm lengths of the JC resonator patches and the arm lengths of the ELC resonator patches of the angular domain dispersion units at different positions are related to the phase required at this position at the operating frequency. By adjusting the arm lengths (L1, L2, L3, L4) of the JC resonator patches and the arm length (C1) of the ELC resonator patches, the phase required at this position can be obtained.

[0113] By adjusting the arm lengths of the JC resonator patches and the arm lengths of the ELC resonator patches, the unit can achieve a phase response change from -250° to 110° under the incidence of electromagnetic waves at ±45°.

[0114] The relationship between the change in the arm length of the patch and the phase response includes:

[0115] When L1 ranges from 4.01 mm to 2.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 ranges from 1.47 mm to 1.56 mm, and C1 ranges from 0.96 mm to 1.03 mm, a phase response change from -250° to -210° can be achieved for -45° incident electromagnetic waves, and a phase response change from 110° to 70° can be achieved for 45° incident electromagnetic waves simultaneously;

[0116] When L1 is 0.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 ranges from 1.53 mm to 0.55 mm, and C1 ranges from 1.09 mm to 2.86 mm, a phase response change from -200° to -110° can be achieved for -45° incident electromagnetic waves, and a phase response change from 60° to -30° can be achieved for 45° incident electromagnetic waves simultaneously;

[0117] When L1 ranges from 2.55 mm to 4.08 mm, L2 ranges from 5.61 mm to 4.08 mm, L3 and L4 are both 1 mm, and C1 ranges from 3.2 mm to 4.8 mm, a phase response change from -100° to -70° can be achieved for -45° incident electromagnetic waves, and a phase response change from -40° to -70° can be achieved for 45° incident electromagnetic waves simultaneously;

[0118] When L1 ranges from 4.08 mm to 5.61 mm, L2 ranges from 4.08 mm to 2.55 mm, L3 and L4 are both 1 mm, and C1 ranges from 4.8 mm to 3.2 mm, a phase response change from -70° to -40° can be achieved for -45° incident electromagnetic waves, and a phase response change from -70° to -100° can be achieved for 45° incident electromagnetic waves simultaneously;

[0119] When L1 is 6.5 mm, L2 is 0.5 mm, L3 ranges from 0.55 mm to 1.53 mm, L4 is 0.2 mm, and C1 ranges from 2.86 mm to 1.09 mm, a phase response change from -30° to 60° can be achieved for -45° incident electromagnetic waves, and a phase response change from -110° to -200° can be achieved for 45° incident electromagnetic waves simultaneously;

[0120] When L1 is 6.5 mm, L2 ranges from 2.5 mm to 4.01 mm, L3 ranges from 1.56 mm to 1.47 mm, L4 is 0.2 mm, and C1 ranges from 1.03 mm to 0.96 mm, a phase response change from 70° to 110° can be achieved for -45° incident electromagnetic waves, and a phase response change from -210° to -250° can be achieved for 45° incident electromagnetic waves simultaneously;

[0121] The material of the metal pattern layer is copper, the relative dielectric constant of the dielectric substrate is 10.2, and the thickness is 0.635 mm. The size of the unit is 5 mm * 5 mm * 3.5 mm.

[0122] The center of the metasurface is the origin, and the coordinates of the centers of other units relative to the origin are (x i , y i ). The phase response Φ1 required to achieve an l-order OAM beam is: Φ1 = l·tan -1 (y i / x i ) + Φ0.

[0123] where l = 0, ±1, ±2..., and Φ0 is the phase response of the unit at the coordinate (0, 0).

[0124] The plane electromagnetic wave with an incident angle of θ i vertically exits through the metasurface and satisfies the generalized Snell's law:

[0125]

[0126] where λ0 is the vacuum wavelength, dx is the distance between adjacent units, and dΦ is the phase difference between adjacent units.

[0127] According to the generalized Snell's law, the phase response Φ2 of each unit during vertical exit needs to satisfy:

[0128]

[0129] Let Φ0 = 0, where θ i = 0°, ±45°.

[0130] To achieve the vertical exit of the OAM beam, the total phase response Φ required for the unit at the coordinate (x i , y i ) should satisfy: Φ = Φ1 + Φ2.

[0131] The angular dispersion metasurface composed of units is approximately square, with no specific size limit, and the number of units in the x-direction and y-direction is approximately 7:10.

[0132] In this article, specific examples are used to elaborate on the principle and implementation method of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An orbital angular momentum vortex electromagnetic wave multiplexing device, characterized in that, Comprising: A plurality of angular dispersion units; The angular dispersion units are arranged in an array uniformly to form an angular dispersion metasurface; The angular dispersion unit includes: an ELC resonator patch layer, a JC resonator patch layer, and a dielectric substrate layer; the dielectric substrate layer is disposed between the ELC resonator patch layer and the JC resonator patch layer; The arm length parameters of each of the ELC resonator patch layer and the JC resonator patch layer are determined by the required phase response; the required phase response is the phase response required for each of the angular dispersion units to ensure that the output wave exits vertically; The phase response required for each of the angular dispersion units to ensure that the output wave exits vertically is determined according to the formula Φ1 = l·tan -1 (y i / x i ) + Φ0 and the formula ; where Φ1 represents the phase response required to achieve an l-order OAM beam, (x i , y i ) represents the coordinates of the angular dispersion unit in the angular dispersion metasurface, Φ0 represents the phase response at the center of the angular dispersion metasurface, θ i represents the incident angle of the plane electromagnetic wave, and Φ2 represents the phase response required for the angular dispersion unit at vertical exit; When ensuring that the output wave exits vertically, the phase response required for each of the angular dispersion units is Φ, Φ = Φ1 + Φ2; The corresponding relationship between the arm length parameters of each patch in the ELC resonator patch layer and the JC resonator patch layer and the phase response required for the angular dispersion unit is: When L1 is from 4.01 mm to 2.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 is from 1.47 mm to 1.56 mm, and C1 is from 0.96 mm to 1.03 mm, a phase response change from -250° to -210° can be achieved for -45° incident electromagnetic waves, and at the same time, a phase response change from 110° to 70° can be achieved for 45° incident electromagnetic waves; wherein, L1 and L2 represent the lengths of the two large arms of the JC resonator patch layer, L3 and L4 represent the lengths of the two small arms of the JC resonator patch layer, and C1 represents the length of the large arm of the ELC resonator patch layer; When L1 is 0.5 mm, L2 is 6.5 mm, L3 is 0.2 mm, L4 is from 1.53 mm to 0.55 mm, and C1 is from 1.09 mm to 2.86 mm, a phase response change from -200° to -110° can be achieved for -45° incident electromagnetic waves, and at the same time, a phase response change from 60° to -30° can be achieved for 45° incident electromagnetic waves; When L1 is from 2.55 mm to 4.08 mm, L2 is from 5.61 mm to 4.08 mm, L3 and L4 are both 1 mm, and C1 is from 3.2 mm to 4.8 mm, a phase response change from -100° to -70° can be achieved for -45° incident electromagnetic waves, and at the same time, a phase response change from -40° to -70° can be achieved for 45° incident electromagnetic waves; When L1 is from 4.08 mm to 5.61 mm, L2 is from 4.08 mm to 2.55 mm, L3 and L4 are both 1 mm, and C1 is from 4.8 mm to 3.2 mm, a phase response change from -70° to -40° can be achieved for -45° incident electromagnetic waves, and at the same time, a phase response change from -70° to -100° can be achieved for 45° incident electromagnetic waves; When L1 is 6.5 mm, L2 is 0.5 mm, L3 is from 0.55 mm to 1.53 mm, L4 is 0.2 mm, and C1 is from 2.86 mm to 1.09 mm, a phase response change from -30° to 60° can be achieved for -45° incident electromagnetic waves, and at the same time, a phase response change from -110° to -200° can be achieved for 45° incident electromagnetic waves; When L1 is 6.5 mm, L2 is from 2.5 mm to 4.01 mm, L3 is from 1.56 mm to 1.47 mm, L4 is 0.2 mm, and C1 is from 1.03 mm to 0.96 mm, a phase response change from 70° to 110° can be achieved for the -45° incident electromagnetic wave, and at the same time, a phase response change from -210° to -250° can be achieved for the 45° incident electromagnetic wave; For three plane electromagnetic waves incident in different directions, different-mode OAM vortex waves transmitted along the direction perpendicular to the metasurface are generated respectively. When the electromagnetic wave is obliquely incident at θ i = -45°, a vortex wave with an OAM mode number of l is generated, where l = 1, 2...; when the electromagnetic wave θ i = 45° is obliquely incident, a vortex wave with an OAM mode number of -l is generated; when the electromagnetic wave is vertically incident at θ i = 0°, a vortex wave with an OAM mode number of 0 is generated.

2. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The ELC resonator patch layer is composed of two completely symmetrical "T"-shaped metal patches. Among them, the arm length of the vertical patch is C1, the width of the metal patch is 0.2 mm, and the middle interval between the two "T"-shaped metal patches is 0.2 mm; The relative dielectric constant of the dielectric substrate layer is 10.2, and the thickness is 0.635 mm.

3. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The JC resonator patch layer is of a straight-arm type structure; The straight-arm type structure is composed of two "I"-shaped patches, and the two "I"-shaped patches are vertically crossed and rotated 45° at the center.

4. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The JC resonator patch layer is of an arrow type structure; The arrow type structure is composed of a bidirectional arrow-shaped patch and a straight-line patch, and the bidirectional arrow-shaped patch and the straight-line patch are vertically crossed and rotated 45° at the center.

5. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The metal patch of the JC resonator patch layer is inclined 45° along the normal direction of the angular dispersion metasurface.

6. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The size of the angular dispersion unit is 5 mm * 5 mm * 3.5 mm.

7. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The operating frequency of the angular dispersion metasurface is 10 GHz.

8. The orbital angular momentum vortex electromagnetic wave multiplexing device according to claim 1, characterized in that, The number of the angular dispersion units is 26 * 18.

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