Whirlwave beam generation method, apparatus and electronic device

Abstract

The application discloses a vortex beam generation method, device and electronic equipment. The method comprises the following steps: obtaining the radiation electric field of a multi-vortex beam of a holographic metasurface according to the antenna aperture field synthesis principle; determining the form of the holographic metasurface according to the radiation electric field of the multi-vortex beam; exciting a surface wave by using an antenna; and converting the surface wave into a multi-directional and multi-modal vortex beam by using the holographic metasurface with the form. The technical scheme of the application discards a complex feed network, overcomes the defect that an ultra-large profile caused by an air-fed array is difficult to integrate with other terminals, improves beam diffraction, and enhances the quality of orbital angular momentum communication.

Description

Technical Field

[0001] This application relates to the field of antenna design technology, and in particular to a vortex beam generation method, apparatus and electronic device. Background Technology

[0002] With the continuous development of wireless communication and electronic warfare technologies, the demands for data rate, channel utilization, channel capacity, and effective range are increasing. However, according to Shannon's theorem, improving channel capacity using traditional technologies has reached its limit, and significant improvements are difficult to achieve. Therefore, it is urgent to research new technologies to overcome traditional limitations. The emergence of orbital angular momentum has attracted widespread attention from both theoretical and industrial communities. Due to the orthogonality between its different orbital angular momentum modes and the infinite nature of its modes, it can increase channel capacity without increasing bandwidth.

[0003] Traditional methods for generating vortex beams with electromagnetic orbital angular momentum include helical parabolic surfaces, helical phase plates, circular phased arrays, reflection arrays, transmission arrays, radial slot arrays, and single-antenna excitation of higher-order modes. Each of these methods has its own set of drawbacks. For example, helical parabolic surfaces are created by chamfering the aperture of a traditional parabolic antenna, resulting in a single mode output, high precision requirements, and a complex structure. Helical phase plates are helical dielectric plates with low transmission efficiency and strong beam divergence. Circular phased arrays utilize complex feeding networks to power each array element; the number of modes generating orbital angular momentum is related to the number of array elements, meaning that increasing the number of modes requires a corresponding increase in the number of array elements. This conflict between the number of array elements and the spatial arrangement of the antenna limits their application. Reflection arrays and transmission arrays utilize... The unit has wavefront phase modulation capabilities, which modulates the phase of the near-field spherical wave generated by the external feed. Although this avoids a complex feed network, the ultra-high profile caused by the external feed greatly limits its integration with other systems. The radial slot array does not have a complex feed network and has a low profile, which can generate electromagnetic orbital angular momentum. However, it can only generate a beam in the normal direction of the array, which limits its application in the fields of communication and electronic warfare. As for using a single patch antenna to excite higher-order modes to generate orbital angular momentum, the design process is complex, the generated modes are relatively simple, the beam divergence angle is large, and the gain is low. Summary of the Invention

[0004] This application provides a vortex beam generation method, apparatus, and electronic device to eliminate complex feeding networks, overcome the shortcomings of large profiles caused by empty feed arrays that are difficult to integrate with other terminals, and improve beam diffraction to enhance the quality of orbital angular momentum communication.

[0005] The embodiments of this application adopt the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a vortex beam generation method, including:

[0007] Based on the principle of antenna aperture field synthesis, the radiated electric field of the multi-vortex beam of the holographic metasurface is obtained;

[0008] The morphology of the holographic metasurface is determined based on the radiated electric field of the multi-vortex beam.

[0009] Excite surface waves using an antenna;

[0010] The surface waves are converted into multi-directional, multi-mode vortex beams using a holographic metasurface with this morphology.

[0011] Secondly, embodiments of this application also provide a vortex beam generating device, comprising:

[0012] The radiation electric field calculation unit is used to obtain the radiation electric field of the multi-vortex beam of the holographic metasurface based on the principle of antenna aperture field synthesis.

[0013] A surface morphology determination unit is used to determine the morphology of the holographic metasurface based on the radiative electric field of the multi-vortex beam.

[0014] Surface wave excitation unit, used to excite surface waves using an antenna;

[0015] A beam generation unit is used to convert surface waves into multi-directional, multi-mode vortex beams using a holographic metasurface with this shape.

[0016] Thirdly, embodiments of this application also provide an electronic device, including:

[0017] Monopole antenna;

[0018] Processor; and

[0019] The memory is configured to store computer-executable instructions, which, when executed, cause the processor to perform the aforementioned vortex beam generation method.

[0020] The above-mentioned at least one technical solution adopted in the embodiments of this application can achieve the following beneficial effects: Based on the principle of optical holography to microwave electromagnetic target beam reproduction, a holographic metasurface of a specific shape is constructed based on the radiation electric field of multi-vortex beams. On the one hand, the holographic metasurface is used to simultaneously generate multiple vortex beams with different directions and different orbital angular momentum modes, which improves beam diffraction and enhances orbital angular momentum communication quality, channel quality and effective range. On the other hand, the antenna excites surface waves to modulate multi-directional and multi-mode vortex beams. Since the antenna that excites surface waves does not require a complex feeding network, the antenna has a lower profile, which improves the integration effect with other systems. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a schematic flowchart illustrating a vortex beam generation method in one embodiment of this application;

[0023] Figure 2 This is a schematic diagram illustrating the physical mechanism of anisotropic holographic metasurface generating multi-directional, multi-modal Bessel vortex beams in one embodiment of this application.

[0024] Figure 3 The gap size g between impedance surface units at adjacent locations in the anisotropic holographic metasurface that generates diffraction-free double Bessel vortex beams, as shown in one embodiment of this application. a Distribution diagram;

[0025] Figure 4 The gap angle θ between impedance surface units at adjacent locations in an anisotropic holographic metasurface that generates diffraction-free double Bessel vortex beams, as shown in one embodiment of this application. t Distribution diagram;

[0026] Figure 5 This is a 3D far-field radiation pattern of a dual Bessel vortex beam operating at 30 GHz, as shown in one embodiment of this application.

[0027] Figure 6 This is a near-field distribution diagram of x-polarization of a dual Bessel vortex beam operating at 30 GHz, as shown in one embodiment of this application.

[0028] Figure 7 This is a schematic diagram of the structure of a vortex wave velocity generating device shown in one embodiment of this application;

[0029] Figure 8 This is a schematic diagram of the structure of an electronic device shown in one embodiment of this application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] The technical solutions provided by the various embodiments of this application are described in detail below with reference to the accompanying drawings.

[0032] This application provides a vortex beam generation method to eliminate the need for traditional complex feed networks, overcome the shortcomings of large profiles caused by empty feed arrays that are difficult to integrate with other terminals, and improve beam diffraction to enhance the quality of orbital angular momentum communication.

[0033] Figure 1 This is a flowchart illustrating a vortex beam generation method in one embodiment of this application, as shown below. Figure 1 As shown, the vortex beam generation method of this application embodiment includes at least the following steps S110-S140:

[0034] Step S110: Based on the principle of antenna aperture field synthesis, obtain the radiation electric field of the multi-vortex beam of the holographic metasurface.

[0035] Vortex electromagnetic waves are a type of dark, hollow beam with a helical wavefront. The Poynting vector of a vortex beam has an azimuth component, so the vortex beam carries a certain amount of orbital angular momentum. In this embodiment, vortex beams include, for example, higher-order Bessel vortex electromagnetic waves with typical different topological charges, Hermetic-Gaussian vortex electromagnetic waves, Laguerre-Gaussian vortex electromagnetic waves, Airy-Gaussian vortex electromagnetic waves, and other types, such as doughnut and hypergeometric vortex electromagnetic waves.

[0036] In this embodiment, the multi-vortex beam refers to multiple vortex beams with multiple different propagation directions and carrying multiple different modes, that is, each vortex beam has a different propagation direction and / or carries a different mode.

[0037] Step S120: Determine the morphology of the holographic metasurface based on the radiated electric field of the multi-vortex beam.

[0038] refer to Figure 2 As shown, the holographic metasurface in this embodiment is an anisotropic metasurface. The holographic metasurface includes m×n periodically arranged impedance surface units. Each impedance surface unit includes a dielectric substrate, a metal patch printed on the center of the upper surface of the dielectric substrate, and a metal ground plane on the lower surface. The slit angles of the metal patches in each impedance surface unit are different, and the slit sizes between the metal patches of adjacent impedance surface units are different. After determining the slit angles of the metal patches in each impedance surface unit and the slit sizes between the metal patches of adjacent impedance surface units, the shape of the holographic metasurface can be determined based on the slit angles and slit sizes.

[0039] The holographic metasurface exemplarily includes a square metasurface, and each metal patch exemplarily includes a rectangular metal patch. In practical applications, those skilled in the art can flexibly set the shape of the holographic metasurface and the shape of the metal patches.

[0040] Step S130: Excite surface waves using an antenna.

[0041] The antenna in this embodiment can be any antenna capable of generating a two-dimensional current field, including, for example, a monopole antenna.

[0042] Step S140: The surface wave is converted into a multi-directional, multi-mode vortex beam using a holographic metasurface with this shape.

[0043] The embodiments of this application generate vortex beams based on the principle of reproducing microwave electromagnetic target beams from optical holography. That is, the vortex beams interfere with surface waves to produce alternating bright and dark fringes. Anisotropic impedance surface units with different geometric parameters represent the bright and dark fringes. When the antenna excites and generates surface waves, the holographic metasurface will regulate the surface waves to realize the target vortex beam.

[0044] visible, Figure 1 The method shown is based on the principle of reproducing optical holography into microwave electromagnetic target beams. It constructs a holographic metasurface of a specific shape based on the radiated electric field of a multi-vortex beam. On the one hand, the holographic metasurface is used to simultaneously generate multiple vortex beams with different directions and orbital angular momentum modes, improving beam diffraction and enhancing orbital angular momentum communication quality, channel quality, and effective range. On the other hand, the antenna excites surface waves to modulate multi-directional, multi-mode vortex beams. Since the antenna that excites surface waves does not require a complex feeding network, the antenna has a lower profile, improving the integration effect with other systems.

[0045] In some embodiments, the radiated electric field of the multi-vortex beam of the holographic metasurface is obtained according to the principle of antenna aperture field synthesis, including:

[0046] The reference radiation electric fields of each vortex beam carrying different modes in different propagation directions are obtained, and the reference radiation electric fields of each vortex beam are superimposed to obtain the radiation electric field of the multi-vortex beam of the holographic metasurface.

[0047] This process obtains the reference radiation electric field of each vortex beam carrying different modes in different propagation directions, including: calculating the angular direction of the plane perpendicular to the radiation direction of the vortex beam in the hyperplane coordinate system based on the radiation direction of the vortex beam and the spatial coordinate transformation relationship; and obtaining the reference radiation electric field corresponding to the vortex beam based on the angular direction. The spatial coordinate transformation relationship is the relative positional relationship between the reference coordinate system of the vortex beam and the hyperplane coordinate system.

[0048] The reference coordinate system of the vortex beam can be understood as a local coordinate system established with the propagation direction of the vortex beam as the z-axis, and the hyperplane coordinate system can be understood as a global coordinate system established with the center point of the holographic hyperplane as the origin and the upper surface of the hyperplane as the xOy plane.

[0049] In practical applications, a target vortex beam can be selected according to application requirements, and the morphology of the holographic metasurface can be determined based on the radiation electric field of the selected target vortex beam. For example, in order to obtain a multi-directional, multi-mode, low-diffraction (or non-diffraction) vortex beam, the radiation electric field of a multi-Bessel beam can be selected to determine the morphology of the holographic metasurface.

[0050] The inventors of this application have discovered that introducing anisotropic holographic metasurfaces into the vortex beam generation process can solve the problem in related technologies where the overall antenna profile is high and difficult to integrate with other systems due to the need for an external feed source to generate vortex beams using an air-fed array antenna. Furthermore, the anisotropic impedance surface unit offers high flexibility in modulation.

[0051] Based on this, in some embodiments, the morphology of the holographic metasurface is determined according to the radiated electric field of the multi-vortex beam, including:

[0052] The modulation tensor impedance between the radiated electric field of the multi-vortex beam and the reference wave is calculated based on the principle of holographic impedance reconstruction. The reference wave is a surface wave generated by antenna excitation. Based on the preset constraints and the modulation tensor impedance, the slit angle and slit size of the impedance surface element at each position of the holographic metasurface are calculated. The morphology of the anisotropic holographic metasurface is determined based on the slit angle and slit size of the impedance surface element at each position of the holographic metasurface.

[0053] refer to Figure 2 The anisotropic holographic metasurface that generates vortex beams mainly consists of two parts: a feed antenna that excites and generates surface waves, and a microstrip array composed of impedance surface elements arranged in a certain pattern.

[0054] The length of the feed antenna in the feeding section is typically λ / 4, where λ is the wavelength of the electromagnetic wave in free space. For example, the feeding section includes a cylindrical opening, and the overall antenna impedance matching can be achieved by adjusting the opening radius to reduce the reflection coefficient. In scalar impedance modulation, the target radiation beam term can be obtained by modulating surface waves with impedance patterns. In the case of tensor impedance, when the reference wave excites and modulates the tensor impedance proportional to a certain value, the target vector radiation beam term can be achieved by exciting and modulating the tensor impedance surface with vector surface waves, thereby obtaining the modulation tensor impedance of the impedance surface elements at various locations on the holographic metasurface.

[0055] In this embodiment, the preset constraint is that the gap angle of an impedance surface element is equal to the azimuth angle of the maximum effective scalar impedance of that impedance surface element. The azimuth angle of the maximum effective scalar impedance is obtained through the following steps:

[0056] Based on the interference relationship between the radiated electric field of the multi-vortex beam and the reference wave, and based on the modulation tensor impedance of the impedance surface element at each position of the holographic metasurface, the modulation impedance component of the impedance surface element at each position of the holographic metasurface is determined; the effective scalar impedance of the impedance surface element at each position of the holographic metasurface is obtained based on the modulation impedance component; and the azimuth angle corresponding to the maximum effective scalar impedance of the impedance surface element at each position is obtained based on the expression of the effective scalar impedance.

[0057] In this embodiment, the calculation process for the slit angle and slit size of the impedance surface unit at various locations on the holographic metasurface is as follows:

[0058] The effective scalar impedance maximum value corresponding to the gap size of the impedance surface element at each location of the holographic metasurface is calculated using the full-wave simulation method. Based on the gap size of the impedance surface element at each location of the holographic metasurface and its corresponding effective scalar impedance maximum value, a relationship curve between the effective scalar impedance maximum value and the gap size is fitted. Based on this relationship curve, the gap angle and gap size of the impedance surface element at each location of the holographic metasurface are calculated.

[0059] To illustrate the process of generating multi-directional, multi-modal vortex beams in the embodiments of this application in more detail, the process of generating Bessel vortex beams will be used as an example.

[0060] To facilitate the description of the relevant functions in the Bessel vortex beam generation process, a hyperplane coordinate system Oxyz is pre-constructed. The origin of the coordinate system is located at the geometric center of the uppermost metal layer of the holographic metasurface antenna. The xOy plane is located above the holographic metaplane, where the x-axis is parallel to one side of the metasurface, and the positive z-axis is perpendicular to the metasurface and pointing upwards. The x, y, and z-axis directions follow the right-hand rule.

[0061] The first step, after establishing the hyperplane coordinate system, is to calculate the radiated electric field Eo of the multi-Bessel vortex beam on the holographic metasurface. bj ;

[0062]

[0063] In equation (1), (1,0,0) represents that the linear polarization direction is along the x-axis. The wave vector representing the i-th Bessel vortex beam. δ represents the position coordinate vector of the (m,n)th impedance surface element. i n represents the cone angle of the i-th non-diffractive higher-order Bessel wave beam. iThis represents the magnitude of the i-th beam in the direction of propagation. It is the angular angle of the plane perpendicular to the propagation direction of the i-th wave, and j is the imaginary unit.

[0064]

[0065] Represents the radiation direction of the i-th Bessel vortex beam, (x mn ,y mn ) represents the coordinates of the (m,n)th array element.

[0066] The second step is to determine the radiated electric field E of the Dobessel vortex beam. obj and reference wave J surf Calculate the modulation tensor impedance of the impedance surface unit at various locations on the holographic metasurface.

[0067] In this embodiment, the power supply for the monopole antenna is positioned at the center of the anisotropic holographic metasurface plane, and the reference wave is generated by the quarter-dielectric wavelength monopole antenna excitation. n e The refractive index parameters of the distribution pattern of the impedance surface unit. It is the electromagnetic wave vector, (x mn ,y mn ) represents the coordinates of the (m,n)th array element.

[0068] According to the principle of holographic impedance reconstruction, the tensor impedance distribution is determined by the reference wave J. surf With the radiated electric field E obj The outer product determines the target vector radiation beam term E. obj |J surf | 2 It is obtained by modulating the surface wave of the scattering vector of the anisotropic holographic metasurface. The following expression can then be obtained:

[0069]

[0070] In equation (2), Represents Hermite conjugate, Representing the vector outer product, Z represents the modulation tensor impedance, expressed as:

[0071]

[0072] In equation (3), X represents the average value of the inductive reactance, and M represents the normalized modulation depth.

[0073] The third step is to determine the morphology of the holographic metasurface.

[0074] According to equation (1), when the multi-vortex beam is a multi-Bessel vortex beam, the radiated electric field Eobj This includes the polarization mode of the vortex beam, the radiation direction of each Bessel vortex beam, the mode number, and the non-diffraction cone angle of each Bessel vortex beam;

[0075] The vortex beams are linearly polarized, and the non-diffraction cone angles of each Bessel vortex beam satisfy (λ / 4D) < tanδ. i λ is the wavelength of the electromagnetic wave in free space, D is the aperture size of the antenna, and δ i It is the non-diffraction cone angle of the i-th Bessel vortex beam; optionally, the mode number of each Bessel vortex beam is -3≤n. i ≤+3, the propagation direction of the i-th Bessel vortex beam is represented by... This means that 0°≤θ i ≤70°

[0076] For example, if we select two Bessel vortex beams with modes n1 = 1 and n2 = -1 in different directions, the radiation directions of the two beams are respectively and Their non-diffraction cone angles are δ1=δ2=4°, and the antenna operating frequency is f=30GHz.

[0077] At this point, it can be determined that the polarization of the Bessel vortex beam is linear, represented as (1,0,0), and the radiation directions of the two beams are respectively... and Their non-diffraction cone angles are δ1=δ2=4°.

[0078] Next, the three modulation impedance components of the anisotropic impedance surface unit at various locations on the holographic metasurface are calculated:

[0079]

[0080]

[0081] Z yy =jX

[0082] Based on these three modulation impedance components, the effective scalar impedance of the anisotropic impedance surface element at each location is:

[0083]

[0084] In equation (4), k z Let θ be the wave number propagating along the z-axis, k be the free-space beam, Z0 be the free-space impedance, and θ be the free-space wave number. s It's the angle of propagation, tanθ s =k sy / k sx ksy It is the y-component of the reference wave vector, k sx It is the x-component of the reference wave vector.

[0085] After calculating the effective scalar impedance, the free-space wavenumber k can be obtained based on the antenna operating frequency. The free-space wave impedance Z0 and the three modulation impedance components Z... xx Z yy and Z xy Substituting into equation (4), based on the gap angle θ of the rectangular gap on the metal patch... t The azimuth angle θ of the maximum effective scalar impedance emax Approximately equal, the maximum effective scalar impedance Z of the impedance surface element at each location in the holographic metasurface is calculated. emax and its corresponding azimuth angle θ emax The effective scalar impedance maximum value Z corresponding to the gap size of the metal patch between adjacent impedance surface elements was calculated using the full-wave simulation method. emax The relationship curve between the two is fitted, and the gap size g of the impedance surface unit at each location of the holographic metasurface is calculated based on the relationship curve. a and the corresponding gap angle θ t Based on the calculated gap size g a and its corresponding gap angle θ t Determine the morphology of anisotropic holographic metasurfaces.

[0086] The fourth step is to weld the monopole antenna as a feed to the center of the holographic metasurface, perpendicular to the holographic metasurface. The surface wave is excited by the monopole antenna as a feed and converted into a multi-mode, multi-directional, low-diffraction Bessel vortex beam by the holographic metasurface.

[0087] After generating the Bessel vortex beam through the above steps, the technical effects of this application are illustrated by combining simulation experiments with the embodiments of this application. The simulation software HFSS_15.0 and Matlab were used to jointly construct two anisotropic holographic metasurfaces of 212.5mm × 212.5mm, each composed of 85×85 anisotropic impedance surface units.

[0088] Under the above simulation conditions, the gap size g between impedance surface units at adjacent positions in the anisotropic holographic metasurface of this embodiment is simulated. a and gap angle θ t The distribution results are as follows Figure 3 and Figure 4 As shown, this result can determine the geometry of the holographic metasurface.

[0089] The 3D far-field radiation pattern of the dual Bessel vortex beam operating at 30 GHz, generated under the above simulation conditions, is shown in the figure below. Figure 5 As shown, Figure 5 This indicates the existence of two distinct radiative hollows in the radiation direction of the Dobessel beam, a phenomenon consistent with the inherent property of electromagnetic waves carrying orbital angular momentum.

[0090] The near-field distribution of the x-polarization of the dual Bessel vortex beam operating at 30 GHz, generated under the simulation conditions described above, is shown in the figure below. Figure 6 As shown, Figure 6 This indicates that the diffraction degree of the 30GHz multi-Bessel vortex beam is lower than that of the traditional vortex wave.

[0091] In summary, the embodiments of this application can simultaneously generate multi-mode, multi-directional, low-diffraction Bessel vortex beams through the above four steps. The entire generation process does not require a complex feeding network, does not have a large profile caused by an external feed source, and is easy to integrate with other systems. Moreover, it can simultaneously generate multiple Bessel vortex beams with different directions and different orbital angular momentum modes, improving the beam diffraction in the prior art and helping to enhance the quality of orbital angular momentum communication, channel quality, and effective operating range.

[0092] Furthermore, the embodiments of this application employ anisotropic impedance surface element design for the holographic metasurface, enabling independent control of surface waves in each direction. This allows for easy and flexible control of beam polarization, direction, and the number of modes carrying orbital angular momentum. Moreover, the antennas in the embodiments of this application utilize mature circuit printing technology, making them easy to manufacture and readily applicable.

[0093] This application also provides a vortex beam generating device for implementing the vortex beam generating method in any of the above embodiments.

[0094] Figure 7 This is a schematic diagram of the structure of a vortex beam generating device shown in one embodiment of this application. Figure 7 As shown, the vortex beam generating device 700 includes:

[0095] The radiation electric field calculation unit 710 is used to obtain the radiation electric field of the multi-vortex beam of the holographic metasurface based on the principle of antenna aperture field synthesis.

[0096] The surface morphology determination unit 720 is used to determine the morphology of the holographic metasurface based on the radiative electric field of the multi-vortex beam.

[0097] Surface wave excitation unit 730 is used to excite surface waves using an antenna;

[0098] The beam generation unit 740 is used to convert surface waves into multi-directional, multi-mode vortex beams using a holographic metasurface with this shape.

[0099] In some embodiments, the radiation electric field calculation unit 710 is used to obtain the reference radiation electric field of each vortex beam carrying different modes in different propagation directions; and to superimpose the reference radiation electric fields of each vortex beam to obtain the radiation electric field of the multi-vortex beam of the holographic metasurface.

[0100] In some embodiments, the radiation electric field calculation unit 710 is further configured to calculate the angular direction of a plane perpendicular to the radiation direction of the vortex beam in the hyperplane coordinate system based on the radiation direction of the vortex beam and the spatial coordinate transformation relationship; wherein the spatial coordinate transformation relationship is the relative positional relationship between the reference coordinate system of the vortex beam and the hyperplane coordinate system; and obtain the reference radiation electric field corresponding to the vortex beam based on the angular direction.

[0101] In some embodiments, the multi-vortex beam is a multi-Bessel vortex beam, and the radiated electric field includes the vortex beam polarization, the radiation direction of each Bessel vortex beam, the mode number, and the non-diffraction cone angle of each Bessel vortex beam; wherein the vortex beam polarization is linear polarization, and the non-diffraction cone angle of each Bessel vortex beam satisfies (λ / 4D) < tanδ. i λ is the wavelength of the electromagnetic wave in free space, D is the aperture size of the antenna, and δ i It is the non-diffraction cone angle of the i-th Bessel vortex beam.

[0102] In some embodiments, the holographic metasurface is an anisotropic metasurface, which includes m×n periodically arranged impedance surface units. Each impedance surface unit includes a dielectric substrate, a metal patch printed on the center of the upper surface of the dielectric substrate, and a metal ground plane on the lower surface. The gap angles of the metal patches of each impedance surface unit are different, and the gap sizes between the metal patches of adjacent impedance surface units are different.

[0103] In some embodiments, the surface morphology determination unit 720 is used to calculate the modulation tensor impedance between the radiated electric field of the multi-vortex beam and the reference wave according to the holographic impedance reconstruction principle, wherein the reference wave is a surface wave generated by antenna excitation; calculate the slit angle and slit size of the impedance surface element at each location of the holographic metasurface according to the preset constraint conditions and the modulation tensor impedance; wherein the preset constraint condition is that the slit angle of an impedance surface element is equal to the azimuth angle of the maximum effective scalar impedance of the impedance surface element; and determine the morphology of the anisotropic holographic metasurface according to the slit angle and slit size of the impedance surface element at each location of the holographic metasurface.

[0104] In some embodiments, the surface morphology determination unit 720 is further configured to determine the modulation impedance components of the impedance surface elements at various locations of the holographic metasurface based on the interference relationship between the radiated electric field of the multi-vortex beam and the reference wave, and based on the modulation tensor impedance of the impedance surface elements at various locations of the holographic metasurface; obtain the effective scalar impedance of the impedance surface elements at various locations of the holographic metasurface based on the modulation impedance components; and obtain the azimuth angle corresponding to the maximum effective scalar impedance of the impedance surface elements at various locations based on the expression of the effective scalar impedance.

[0105] In some embodiments, the surface morphology determination unit 720 is further configured to calculate the maximum effective scalar impedance corresponding to the gap size of the impedance surface unit at each location of the holographic metasurface using a full-wave simulation method; fit a relationship curve between the maximum effective scalar impedance and the gap size based on the gap size of the impedance surface unit at each location of the holographic metasurface and its corresponding maximum effective scalar impedance; and calculate the gap angle and gap size of the impedance surface unit at each location of the holographic metasurface based on the relationship curve.

[0106] It is understood that the above-described vortex beam generating device can realize each step of the vortex beam generating method provided in the foregoing embodiments. The relevant explanations of the vortex beam generating method are applicable to the vortex beam generating device, and will not be repeated here.

[0107] Figure 8 This is a schematic diagram of the structure of an electronic device according to an embodiment of this application. Please refer to it. Figure 8 At the hardware level, the electronic device includes a monopole antenna, a processor, and memory, and optionally also includes an internal bus and a network interface. The memory may include RAM, such as high-speed random-access memory (RAM), or non-volatile memory, such as at least one disk drive. Of course, the electronic device may also include other hardware required for other services.

[0108] The processor, network interface, and memory can be interconnected via an internal bus, which can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 8 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0109] Memory is used to store programs. Specifically, programs may include program code, which includes computer operation instructions. Memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0110] The processor reads the corresponding computer program from non-volatile memory into main memory and then executes it, forming a vortex beam generator at the logical level. The processor executes the program stored in memory and specifically performs the following operations:

[0111] Based on the principle of antenna aperture field synthesis, the radiated electric field of the multi-vortex beam of the holographic metasurface is obtained; the morphology of the holographic metasurface is determined based on the radiated electric field of the multi-vortex beam; the surface wave is excited using an antenna; and the surface wave is converted into a multi-directional, multi-mode vortex beam using the morphologically defined holographic metasurface.

[0112] The above is as stated in this application. Figure 1 The method executed by the vortex beam generating device disclosed in the illustrated embodiment can be applied to a processor or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software module can reside in a mature storage medium in the field, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0113] The electronic device can also perform Figure 1The method for executing a vortex beam generator, and the realization of the vortex beam generator in... Figure 1 The functions of the embodiments shown are not described in detail here.

[0114] This application also proposes a computer-readable storage medium that stores one or more programs, the programs including instructions that, when executed by an electronic device including multiple applications, enable the electronic device to perform... Figure 1 The method executed by the vortex beam generating device in the illustrated embodiment is specifically used to perform:

[0115] Based on the principle of antenna aperture field synthesis, the radiated electric field of the multi-vortex beam of the holographic metasurface is obtained; the morphology of the holographic metasurface is determined based on the radiated electric field of the multi-vortex beam; the surface wave is excited using an antenna; and the surface wave is converted into a multi-directional, multi-mode vortex beam using the morphologically defined holographic metasurface.

[0116] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0117] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0118] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0119] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0120] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0121] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0122] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0123] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0124] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0125] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for generating a vortex beam, characterized in that, include: Based on the principle of antenna aperture field synthesis, the radiated electric field of the multi-vortex beam of the holographic metasurface is obtained; The morphology of the holographic metasurface is determined based on the radiated electric field of the multi-vortex beam. Excite surface waves using an antenna; The surface wave is converted into a multi-directional, multi-mode vortex beam using a holographic metasurface with the aforementioned shape. The determination of the morphology of the holographic metasurface based on the radiated electric field of the multi-vortex beam includes: The modulation tensor impedance between the radiated electric field of the multi-vortex beam and the reference wave is calculated based on the principle of holographic impedance reconstruction, wherein the reference wave is a surface wave generated by the antenna excitation. Based on the preset constraints and the modulation tensor impedance, the slit angle and slit size of the impedance surface unit at each position of the holographic metasurface are calculated; wherein the preset constraint is that the slit angle of an impedance surface unit is equal to the azimuth angle of the maximum effective scalar impedance of the impedance surface unit. The morphology of the anisotropic holographic metasurface is determined based on the slit angle and slit size of the impedance surface units at various locations of the holographic metasurface. The multi-vortex beam is a multi-Bessel vortex beam, and the radiation electric field includes the vortex beam polarization mode, the radiation direction of each Bessel vortex beam, the mode number, and the non-diffraction cone angle of each Bessel vortex beam. The vortex beams are linearly polarized, and the non-diffraction cone angles of each Bessel vortex beam satisfy (λ / 4D) < tanδ. i λ is the wavelength of the electromagnetic wave in free space, D is the aperture size of the antenna, and δ i It is the non-diffraction cone angle of the i-th Bessel vortex beam; n i It is the mode number in the propagation direction of the i-th Bessel vortex beam, -3≤n i ≤+3, the propagation direction of the i-th Bessel vortex beam is represented by... This means that 0°≤θ i ≤70° The holographic metasurface is an anisotropic metasurface, comprising m×n periodically arranged impedance surface units. Each impedance surface unit includes a dielectric substrate, a metal patch printed on the center of the upper surface of the dielectric substrate, and a metal ground plane on the lower surface. The gap angles of the metal patches in each impedance surface unit are different, and the gap sizes between the metal patches of adjacent impedance surface units are different.

2. The method according to claim 1, characterized in that, Based on the principle of antenna aperture field synthesis, the radiated electric field of the multi-vortex beam of the holographic metasurface is obtained, including: Obtain the reference radiated electric field of each vortex beam carrying different modes in different propagation directions; By superimposing the reference radiation electric fields of each vortex beam, the radiation electric field of the multi-vortex beam of the holographic metasurface is obtained.

3. The method according to claim 2, characterized in that, The acquisition of the reference radiated electric field of each vortex beam carrying different modes in different propagation directions includes: Based on the radiation direction of the vortex beam and the spatial coordinate transformation relationship, calculate the angular direction of the plane perpendicular to the radiation direction of the vortex beam in the hyperplane coordinate system; where the spatial coordinate transformation relationship is the relative positional relationship between the reference coordinate system of the vortex beam and the hyperplane coordinate system. The reference radiation electric field corresponding to the vortex beam is obtained based on the angular direction angle.

4. The method according to claim 1, characterized in that, The azimuth angle of the maximum effective scalar impedance is obtained by following these steps: Based on the interference relationship between the radiated electric field of the multi-vortex beam and the reference wave, and based on the modulation tensor impedance of the impedance surface unit at each location of the holographic metasurface, the modulation impedance components of the impedance surface unit at each location of the holographic metasurface are determined. The effective scalar impedance of the impedance surface unit at each location of the holographic metasurface is obtained based on the modulation impedance component. The azimuth angle corresponding to the maximum effective scalar impedance of the impedance surface element at each location is obtained according to the expression of the effective scalar impedance.

5. The method according to claim 4, characterized in that, The step of calculating the slit angle and slit size of the impedance surface unit at each position of the holographic metasurface based on the preset constraints and the modulation tensor impedance includes: The maximum effective scalar impedance corresponding to the gap size of the impedance surface element at each location on the holographic metasurface was calculated using the full-wave simulation method. Based on the gap size of the impedance surface unit at each location of the holographic metasurface and its corresponding maximum effective scalar impedance, fit the relationship curve between the maximum effective scalar impedance and the gap size; Based on this relationship curve, the gap angle and gap size of the impedance surface unit at each location of the holographic metasurface are calculated.

6. A vortex beam generating device, characterized in that, include: The radiation electric field calculation unit is used to obtain the radiation electric field of the multi-vortex beam of the holographic metasurface based on the principle of antenna aperture field synthesis. A surface morphology determination unit is used to determine the morphology of the holographic metasurface based on the radiative electric field of the multi-vortex beam. Surface wave excitation unit, used to excite surface waves using an antenna; A beam generation unit is used to convert the surface wave into a multi-directional, multi-mode vortex beam using a holographic metasurface with the aforementioned shape. The surface morphology determination unit is used for: The modulation tensor impedance between the radiated electric field of the multi-vortex beam and the reference wave is calculated based on the principle of holographic impedance reconstruction, wherein the reference wave is a surface wave generated by the antenna excitation. Based on the preset constraints and the modulation tensor impedance, calculate the slit angle and slit size of the impedance surface unit at each position of the holographic metasurface; The preset constraint condition is that the slit angle of an impedance surface element is equal to the azimuth angle of the maximum effective scalar impedance of the impedance surface element. The morphology of the anisotropic holographic metasurface is determined based on the slit angle and slit size of the impedance surface units at various locations of the holographic metasurface. The multi-vortex beam is a multi-Bessel vortex beam, and the radiation electric field includes the vortex beam polarization mode, the radiation direction of each Bessel vortex beam, the mode number, and the non-diffraction cone angle of each Bessel vortex beam. The vortex beams are linearly polarized, and the non-diffraction cone angles of each Bessel vortex beam satisfy (λ / 4D) < tanδ. i λ is the wavelength of the electromagnetic wave in free space, D is the aperture size of the antenna, and δ i It is the non-diffraction cone angle of the i-th Bessel vortex beam; n i It is the mode number in the propagation direction of the i-th Bessel vortex beam, -3≤n i ≤+3, the propagation direction of the i-th Bessel vortex beam is represented by... This means that 0°≤θ i ≤70° The holographic metasurface is an anisotropic metasurface, comprising m×n periodically arranged impedance surface units. Each impedance surface unit includes a dielectric substrate, a metal patch printed on the center of the upper surface of the dielectric substrate, and a metal ground plane on the lower surface. The gap angles of the metal patches in each impedance surface unit are different, and the gap sizes between the metal patches of adjacent impedance surface units are different.

7. An electronic device, comprising: Monopole antenna; processor; as well as A memory configured to store computer-executable instructions, which, when executed, cause the processor to perform any of the vortex beam generation methods of claims 1 to 5.

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