Beam-harvesting metasurface

Abstract

This invention proposes a beam-converging metasurface, comprising a dielectric substrate, a metasurface array printed on the upper surface of the dielectric substrate, and a metal ground plane disposed on the lower surface of the dielectric substrate. The metasurface array is composed of a periodic array of multiple metasurface units with different encodings and discrete phase responses obtained according to the target beam deflection angle. A phase gradient distribution conforming to the generalized Snell's law is formed between adjacent metasurface units. Each metasurface unit includes a central radiating patch and a phase modulation module connected to it. The phase modulation module includes a phase modulation arm composed of microstrip feed lines. The total length of the phase modulation arm is determined by the discrete phase response of the metasurface unit. This invention solves the problems of large wireless signal attenuation, weak coverage, and poor transmission stability in existing technologies applied to non-line-of-sight communication and sensing scenarios such as indoor office buildings, underground commercial spaces, dense building blocks, and tunnel corridors.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a beam-converging metasurface. Background Technology

[0002] As wireless communication systems expand into complex environments, the demand for wireless applications in urban office buildings, densely populated urban areas, tunnels, underground enclosed spaces, and other confined spaces is increasing. These scenarios often face severe obstruction problems, with limited electromagnetic wave propagation paths and insufficient signal diffraction capabilities, forming typical non-line-of-sight communication environments. This leads to increased wireless signal attenuation, limited coverage, and decreased transmission stability, severely impacting communication quality and environmental awareness performance. Taking scenarios such as building interiors and underground enclosed spaces as examples, electromagnetic wave propagation is easily attenuated by multiple obstacles such as walls, beams, columns, pipelines, and soil structures. Especially when a direct line-of-sight link cannot be established between the transmitting and receiving ends, traditional wireless communication solutions are prone to problems such as signal blind spots, insufficient receiving power, and communication interruptions.

[0003] Existing methods for improving non-line-of-sight (NLS) communication mainly include adding active repeater devices, optimizing antenna layout, and installing metasurfaces. However, while active devices can partially improve coverage, they rely on external power supplies, resulting in high deployment costs and complex maintenance. This makes them unsuitable for long-term use in scenarios with limited power supply and inconvenient maintenance, such as indoor corridors, enclosed underground spaces, tunnels, and densely built-up areas. Traditional metasurfaces have limited ability to modulate electromagnetic waves and cannot effectively enhance scattering and optimize direction according to specific environments, thus exhibiting significant limitations in improving the quality of NLS links.

[0004] To address the aforementioned issues, there is an urgent need for a beam-converging metasurface that requires no external power supply, has a simple structure, and is easy to deploy in non-line-of-sight communication and sensing scenarios such as enclosed indoor spaces, confined underground spaces, and densely built-up areas. This metasurface should effectively enhance electromagnetic scattering and improve propagation paths, thereby improving the transmission performance and scene perception capabilities of wireless signals in complex and obstructed environments, and meeting the stringent requirements of related applications for communication reliability and environmental adaptability. Summary of the Invention

[0005] This invention provides a beam-converging metasurface to at least partially solve one of the technical problems in related technologies. The technical solution of this invention is as follows:

[0006] This invention proposes a beam-converging metasurface, comprising a dielectric substrate, a metasurface array printed on the upper surface of the dielectric substrate, and a metal ground plane disposed on the lower surface of the dielectric substrate. The metasurface array is composed of a periodic array of various metasurface units with different encodings and different discrete phase responses obtained according to the target beam deflection angle. A phase gradient distribution conforming to the generalized Snell's law is formed between adjacent metasurface units, so that the energy of the incident electromagnetic wave converges along the target direction after being reflected by the metasurface array.

[0007] The metasurface unit includes a central radiating patch and a phase control module connected thereto. The phase control module includes a phase control arm composed of microstrip feed lines. The total length of the phase control arm is determined by the discrete phase response of the metasurface unit.

[0008] In some implementations, the metasurface unit includes two phase control modules connected to the side of the central radiating patch corresponding to the preset beam deflection direction. The connection directions of the phase control modules of the various metasurface units and the central radiating patch are all consistent.

[0009] In some implementations, the phase control arm adopts a bent structure.

[0010] In some implementations, the various metasurface units are all square planar structures, the central radiating patch is a square annular structure, the length of the side of the square annular structure is determined by the frequency of the target incident wave, and the center of the central radiating patch coincides with the geometric center of the metasurface unit.

[0011] In some implementations, the various metasurface units are all compact square planar structures, and the various metasurface units include a first metasurface unit, a second metasurface unit, a third metasurface unit, and a fourth metasurface unit.

[0012] The first metasurface unit is used for discrete phase response in the phase ranges of (315°, 360°] and (0°, 45°], the second metasurface unit is used for discrete phase response in the phase range of (45°, 135°], the third metasurface unit is used for discrete phase response in the phase range of (135°, 225°], and the fourth metasurface unit is used for discrete phase response in the phase range of (225°, 315°).

[0013] The phase modulation modules of the first metasurface unit and the second metasurface unit both include a bent structure composed of two phase modulation arms;

[0014] The phase control modules of the third metasurface unit and the fourth metasurface unit both include a bent structure composed of three phase control arms;

[0015] The outer contour side length of the central radiating patch ranges from 13mm to 18mm, the arm width of the phase control arm ranges from 0.6mm to 1mm, and the side lengths of the first metasurface unit, the second metasurface unit, the third metasurface unit, and the fourth metasurface unit all range from 24mm to 26mm.

[0016] In some implementations, the first metasurface unit includes a first central radiating patch, a first phase modulation module, and a second phase modulation module;

[0017] The first phase control module includes a first horizontal phase control arm and a first vertical phase control arm. The right end of the first horizontal phase control arm is connected to the left edge of the first central radiating patch and extends horizontally to the left. The upper end of the first vertical phase control arm is connected to the left end of the first horizontal phase control arm and extends vertically downward.

[0018] The second phase control module includes a second longitudinal phase control arm and a second transverse phase control arm. The upper end of the second longitudinal phase control arm is connected to the lower edge of the first central radiating patch and extends vertically downward. The left end of the second transverse phase control arm is connected to the lower end of the second longitudinal phase control arm and extends horizontally to the right.

[0019] The length of the first lateral phase control arm is the same as the length of the second longitudinal phase control arm, and the length of the first longitudinal phase control arm is the same as the length of the second lateral phase control arm.

[0020] In some implementations, the second metasurface unit includes a second central radiating patch, a third phase modulation module, and a fourth phase modulation module;

[0021] The third phase control module includes a third horizontal phase control arm and a third vertical phase control arm. The right end of the third horizontal phase control arm is connected to the left edge of the second central radiating patch and extends horizontally to the left. The upper end of the third vertical phase control arm is connected to the left end of the third horizontal phase control arm and extends vertically downward.

[0022] The fourth phase control module includes a fourth longitudinal phase control arm and a fourth transverse phase control arm. The upper end of the fourth longitudinal phase control arm is connected to the lower edge of the second central radiating patch and extends vertically downward. The left end of the fourth transverse phase control arm is connected to the lower end of the fourth longitudinal phase control arm and extends horizontally to the right.

[0023] The length of the third lateral phase control arm is the same as the length of the fourth longitudinal phase control arm, and the length of the third longitudinal phase control arm is the same as the length of the fourth lateral phase control arm.

[0024] In some implementations, the third metasurface unit includes a third central radiating patch, a fifth phase modulation module, and a sixth phase modulation module.

[0025] The fifth phase control module includes a fifth horizontal phase control arm, a fifth vertical phase control arm, and a fifth auxiliary phase control arm. The right end of the fifth horizontal phase control arm is connected to the left edge of the third central radiating patch and extends horizontally to the left. The upper end of the fifth vertical phase control arm is connected to the left end of the fifth horizontal phase control arm and extends vertically downward. The left end of the fifth auxiliary phase control arm is connected to the lower end of the fifth vertical phase control arm and extends horizontally to the right.

[0026] The sixth phase control module includes a sixth longitudinal phase control arm, a sixth transverse phase control arm, and a sixth auxiliary phase control arm. The upper end of the sixth longitudinal phase control arm is connected to the lower edge of the third central radiating patch and extends vertically downward. The left end of the sixth transverse phase control arm is connected to the lower end of the sixth longitudinal phase control arm and extends horizontally to the right. The lower end of the sixth auxiliary phase control arm is connected to the right end of the sixth transverse phase control arm and extends vertically upward.

[0027] The length of the fifth lateral phase control arm is the same as the length of the sixth longitudinal phase control arm, the length of the fifth longitudinal phase control arm is the same as the length of the sixth lateral phase control arm, and the length of the fifth auxiliary phase control arm is the same as the length of the sixth auxiliary phase control arm.

[0028] In some implementations, the fourth metasurface unit includes a fourth central radiating patch, a seventh phase modulation module, and an eighth phase modulation module.

[0029] The seventh phase control module includes a seventh horizontal phase control arm, a seventh vertical phase control arm, and a seventh auxiliary phase control arm. The right end of the seventh horizontal phase control arm is connected to the left edge of the fourth central radiating patch and extends horizontally to the left. The upper end of the seventh vertical phase control arm is connected to the left end of the seventh horizontal phase control arm and extends vertically downward. The left end of the seventh auxiliary phase control arm is connected to the lower end of the seventh vertical phase control arm and extends horizontally to the right.

[0030] The eighth phase control module includes an eighth longitudinal phase control arm, an eighth transverse phase control arm, and an eighth auxiliary phase control arm. The upper end of the eighth longitudinal phase control arm is connected to the lower edge of the fourth central radiating patch and extends vertically downward. The left end of the eighth transverse phase control arm is connected to the lower end of the eighth longitudinal phase control arm and extends horizontally to the right. The lower end of the eighth auxiliary phase control arm is connected to the right end of the eighth transverse phase control arm and extends vertically upward.

[0031] The length of the seventh lateral phase control arm is the same as the length of the eighth longitudinal phase control arm, the length of the seventh longitudinal phase control arm is the same as the length of the eighth lateral phase control arm, and the length of the seventh auxiliary phase control arm is the same as the length of the eighth auxiliary phase control arm.

[0032] In some implementations, the lengths of the first lateral phase control arm, the third lateral phase control arm, the fifth lateral phase control arm, and the seventh lateral phase control arm are all the same; the length of the first longitudinal phase control arm is less than the length of the third longitudinal phase control arm; the length of the third longitudinal phase control arm is less than the length of the fifth longitudinal phase control arm; the length of the fifth longitudinal phase control arm is the same as the length of the seventh longitudinal phase control arm; and the length of the eighth auxiliary phase control arm is greater than the length of the fifth auxiliary phase control arm.

[0033] The present invention has the following advantages and beneficial effects:

[0034] By using a metasurface array composed of periodic arrays of various metasurface units with different codes and discrete phase responses obtained according to the target beam deflection angle, the target beam deflection angle can be converted into a phase sequence of the metasurface units and solidified in the array structure. During operation, the incident electromagnetic wave interacts with the preset phase gradient formed by the metasurface array, spontaneously forming a highly directional scattering beam according to physical laws, which can achieve precise electromagnetic wave control; it can optimize the local electromagnetic propagation environment, which is beneficial to reducing weak coverage areas and communication blind spots in indoor enclosed spaces, underground confined spaces, and densely built areas, thereby improving signal coverage blind spots; it solves the problems of large wireless signal attenuation, weak coverage, and poor transmission stability in existing technologies in non-line-of-sight communication and sensing scenarios;

[0035] Based on the reflection principle of metasurface units, the energy of the scattering process originates entirely from the incident electromagnetic wave itself. It is a passive structure that does not require external power supply. Moreover, it has a simple structure, is easy to deploy, has lower deployment costs, and does not rely on continuous power supply. It is suitable for application environments where power supply is difficult and maintenance is inconvenient, such as buried spaces.

[0036] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0038] Figure 1 This is a schematic diagram of the beam-converging metasurface provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of the first metasurface unit provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of the second metasurface unit provided in an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of the third metasurface unit provided in an embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of the fourth metasurface unit provided in an embodiment of the present invention;

[0043] Figure 6 This is a phase gradient distribution diagram of the metasurface array provided in an embodiment of the present invention;

[0044] Figure 7 This is a simulated two-dimensional radar cross-section pattern in an embodiment of the present invention;

[0045] Figure 8 This is a simulated three-dimensional radar cross-section pattern in an embodiment of the present invention.

[0046] Figure label:

[0047] 1. Dielectric substrate; 2. Metasurface array; 3. Metal ground plane; 21. First metasurface unit; 22. Second metasurface unit; 23. Third metasurface unit; 24. Fourth metasurface unit; 211. First central radiating patch; 212. First phase modulation module; 213. Second phase modulation module; 212a. First lateral phase modulation arm; 212b. First longitudinal phase modulation arm; 213a. Second lateral phase modulation arm; 213b. Second longitudinal phase modulation arm; 221. Second central radiating patch; 222. Third phase modulation module; 223. Fourth phase modulation module; 222a. Third lateral phase modulation arm; 222b. Third longitudinal phase modulation arm; 223a. Fourth lateral phase modulation arm; 223b. Fourth longitudinal phase modulation arm. Arms: 231 Third central radiating patch, 232 Fifth phase control module, 233 Sixth phase control module, 232a Fifth lateral phase control arm, 232b Fifth longitudinal phase control arm, 232c Fifth auxiliary phase control arm, 233a Sixth lateral phase control arm, 233b Sixth longitudinal phase control arm, 233c Sixth auxiliary phase control arm, 241 Fourth central radiating patch, 242 Seventh phase control module, 243 Eighth phase control module, 242a Seventh lateral phase control arm, 242b Seventh longitudinal phase control arm, 242c Seventh auxiliary phase control arm, 243a Eighth lateral phase control arm, 243b Eighth longitudinal phase control arm, 243c Eighth auxiliary phase control arm. Detailed Implementation

[0048] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0049] Among related technologies, there are solutions employing leaky coaxial cables and metal reflectors. Leaky coaxial cables are special coaxial cables with periodic slots in their outer conductor. They achieve continuous signal radiation and reception along the path through controlled electromagnetic wave leakage, and are used for wireless communication coverage in underground linear enclosed spaces such as tunnels, mines, and underground utility tunnels. However, leaky coaxial cables require continuous cabling and rely on active repeater power, resulting in high deployment costs, complex maintenance, and difficulty in adapting to nonlinear buried spaces. Metal reflectors utilize the specular reflection characteristics of highly conductive metal surfaces, based on the law that "the angle of incidence equals the angle of reflection," to directionally reflect electromagnetic waves to non-line-of-sight blind spots, thereby constructing alternative propagation paths and improving signal coverage in obstacle-blocked environments. However, metal reflectors can only achieve specular reflection at a fixed angle, lacking the ability to actively control the scattering phase and energy distribution, and are structurally bulky and have poor environmental adaptability. Both of these methods struggle to achieve intelligent reconstruction of electromagnetic wave propagation paths under passive, maintenance-free conditions, hindering the synergistic improvement of communication reliability and sensing capabilities in complex obstructed scenarios.

[0050] The beam-converging metasurface of the present invention is described below with reference to the accompanying drawings.

[0051] like Figure 1 As shown, the beam-converging metasurface provided in this embodiment of the invention includes a dielectric substrate 1, a metasurface array 2 printed on the upper surface of the dielectric substrate 1, and a metal ground plane 3 disposed on the lower surface of the dielectric substrate 1. The metasurface array 2 is formed by a periodic array of multiple metasurface units with different encodings and different discrete phase responses obtained according to the target beam deflection angle. A phase gradient distribution that conforms to the generalized Snell's law is formed between adjacent metasurface units, so that the energy of the incident electromagnetic wave is converged along the target direction after being reflected by the metasurface array.

[0052] The metasurface unit includes a central radiating patch and a phase control module connected to it. The phase control module includes a phase control arm composed of microstrip feed lines. The total length of the phase control arm is determined by the discrete phase response of the metasurface unit.

[0053] As an example, the dielectric substrate 1 is square in shape with a side length of 500 mm and a thickness of 2 mm. It has a relative permittivity of 3 and is made of Rogers RO3003 material with a dielectric loss tangent of 0.01. The dielectric substrate 1 has a flat structure and a uniform thickness distribution. The metasurface array 2 is tightly attached to the upper surface of the dielectric substrate 1. The metal ground plane 3 is tightly attached to the lower surface of the dielectric substrate 1. The upper surface of the dielectric substrate 1 is printed with a metasurface array 2 with a thickness of 0.01 mm, and the length of the metasurface array 2 is equal to the length of the dielectric substrate 1. The lower surface of the dielectric substrate 1 is provided with a metal ground plane 3 with a side length equal to the side length of the dielectric substrate 1 and a thickness of 0.01 mm. Various metasurface units are periodically arranged on the upper surface of the dielectric substrate 1.

[0054] The above structure divides the 360-degree phase of space into multiple continuous intervals using various metasurface units, and quantizes and encodes them into multiple discrete states. Through the coordinated matching design of the central radiating patch and the phase control module, the various metasurface units generate multiple discrete phases that correspond one-to-one with the encoding, and these discrete phases represent any phase within the corresponding interval. For different beam control angles, the target phase required by each metasurface unit in the metasurface array is accurately calculated based on the generalized Snell's law, mapped to the corresponding quantized phase, and the corresponding metasurface units are selected and arranged according to the quantized phase to complete the encoding and arrangement of the metasurface array. Based on the equivalent phase response generated by various metasurface units at the target frequency, and according to the target beam deflection angle, the required phase gradient between adjacent metasurface units is calculated using the generalized Snell's law and periodically arrayed. The gradient distribution of the equivalent electrical length between units is used to achieve precise deflection and directional control of the electromagnetic beam, without the need for external power supply. Based on the above structure, the geometric configuration of the central radiating patch and the key dimensional parameters of the phase control module are optimized to ensure that the metasurface array maintains a stable radiation gain under various target beam deflection angles.

[0055] It should be noted that through the coordinated matching design of the central radiating patch and the phase control module, that is, by adjusting the total length of the phase control arm of each metasurface unit, the discrete phase of each metasurface unit is changed, so that multiple metasurface units generate multiple discrete phases that correspond one-to-one with the target code, and use the discrete phase to represent any phase in the corresponding interval.

[0056] The beam-converging metasurface of this invention can convert the target beam deflection angle into a phase sequence of metasurface units and solidify it in the array structure. During operation, the incident electromagnetic wave interacts with the preset phase gradient formed by the metasurface array, spontaneously forming a highly directional scattering beam according to physical laws, enabling precise electromagnetic wave control. This solution utilizes the reflection principle of the metasurface units, ensuring that the energy of the scattering process originates entirely from the incident electromagnetic wave itself. As a passive structure, it requires no external power supply to optimize the direction, phase, and energy distribution of the scattered wave, effectively overcoming the shortcomings of existing technologies and providing a practical solution for indoor enclosed scenarios. This solution addresses the technical challenges of high wireless signal attenuation, weak signal coverage, and poor transmission stability in complex scenarios such as underground confined spaces and densely built-up areas. It is suitable for applications with limited power supply and maintenance, such as enclosed indoor environments and underground confined spaces. Furthermore, its simple structure makes it easy to deploy. The solution utilizes a low-thickness dielectric substrate, achieving lightweight and easy deployment. Its basic three-layer design facilitates fabrication. This solution balances communication enhancement and perception assistance, catering to non-line-of-sight communication and perception scenarios. In addition to improving communication performance, it provides better electromagnetic propagation conditions for environmental perception, target detection, and status recognition.

[0057] To suppress scattered clutter that is mirror-symmetrical to the preset beam deflection direction along the incident direction, the metasurface unit includes two phase control modules, which are connected to the side of the central radiating patch corresponding to the preset beam deflection direction.

[0058] To achieve a compact design, the phase control arms all adopt a bent structure, which effectively improves the sensitivity of phase changes and ensures precise control of electromagnetic waves while achieving a compact unit structure.

[0059] To suppress electromagnetic coupling between adjacent metasurface units and ensure the accuracy of electromagnetic beam deflection, the connection direction of the phase control module of each metasurface unit must be consistent. Therefore, in this embodiment, the connection direction of the phase control module of various metasurface units to the central radiating patch is consistent.

[0060] In some embodiments, the various metasurface units are all square planar structures, the central radiating patch is a square annular structure, the length of the side of the square annular structure is determined by the frequency of the target incident wave, and the center of the central radiating patch coincides with the geometric center of the metasurface unit.

[0061] In some embodiments, the plurality of metasurface units include a first metasurface unit 21, a second metasurface unit 22, a third metasurface unit 23, and a fourth metasurface unit 24, wherein the first metasurface unit 21 is used for (315°, Discrete phase responses within the phase ranges of [360°] and (0°, 45°], the second metasurface unit 22 is used for discrete phase responses within the phase range of (45°, 135°], the third metasurface unit 23 is used for discrete phase responses within the phase range of (135°, 225°], and the fourth metasurface unit 24 is used for discrete phase responses within the phase range of (225°, 315°); the phase control modules of the first metasurface unit 21 and the second metasurface unit 22 both include a bent structure composed of two phase control arms; the phase control modules of the third metasurface unit 23 and the fourth metasurface unit 24 both include a bent structure composed of three phase control arms; the outer contour side length of the central radiating patch ranges from 13mm to 18mm, the arm width of the phase control arm ranges from 0.6mm to 1mm, and the side length ranges of the first metasurface unit 21, the second metasurface unit 22, the third metasurface unit 23 and the fourth metasurface unit 24 are all from 24mm to 26mm, preferably 25mm.

[0062] As an example, such as Figures 2 to 5As shown, multiple metasurface units include a first metasurface unit 21, a second metasurface unit 22, a third metasurface unit 23, and a fourth metasurface unit 24. An engineered 2-bit quantization method is employed (2 bits, i.e., two binary digits, 00, 01, 10, and 11 correspond to four units; since 3 bits, i.e., three binary digits, 000, 001, 010, 011, 100, 101, 110, and 111 correspond to eight units; the design process is cumbersome, the results are difficult to implement, and the cost is high, this scheme chooses 2-bit quantization). Through these four metasurface units, the 360° phase of space is divided into (315°, ...). The solution uses four continuous intervals: (360°) and (0°, 45°), (45°, 135°), (135°, 225°), and (225°, 315°), and encodes them into four discrete states corresponding to 2 bits. This solution achieves precise deflection beam control through four units corresponding to 2 bits, while also having the advantages of simple structure, easy deployment, controllable cost, and strong engineering feasibility. Based on the equivalent phase response generated by the four metasurface units at the target frequency, the required phase gradient between adjacent metasurface units is calculated according to the target beam deflection angle using the generalized Snell's law, and periodically arrayed. The gradient distribution of the equivalent electrical length between units is used to achieve precise deflection and directional control of the electromagnetic beam, without the need for external power supply.

[0063] Therefore, the metasurface array 2 in this embodiment is composed of a first metasurface unit 21, a second metasurface unit 22, a third metasurface unit 23, and a fourth metasurface unit 24 with four different codes and four different discrete phase responses arranged in a set period according to the preset deflection angle of the target electromagnetic wave; a phase gradient distribution that conforms to the generalized Snell's law is formed between adjacent metasurface units.

[0064] Among them, such as Figure 2As shown, the first metasurface unit 21 includes a first central radiating patch 211, a first phase modulation module 212, and a second phase modulation module 213. The first phase modulation module 212 includes a first lateral phase modulation arm 212a and a first longitudinal phase modulation arm 212b. The right end of the first lateral phase modulation arm 212a is connected to the left edge of the first central radiating patch 211 and extends horizontally to the left. The upper end of the first longitudinal phase modulation arm 212b is connected to the left end of the first lateral phase modulation arm 212a and extends vertically downward. The second phase modulation module 213 includes... The second longitudinal phase control arm 213b and the second transverse phase control arm 213a are connected. The upper end of the second longitudinal phase control arm 213b is connected to the lower edge of the first central radiating patch 211 and extends vertically downward. The left end of the second transverse phase control arm 213a is connected to the lower end of the second longitudinal phase control arm 213b and extends horizontally to the right. The length of the first transverse phase control arm 212a is the same as the length of the second longitudinal phase control arm 213b, and the length of the first longitudinal phase control arm 212b is the same as the length of the second transverse phase control arm 213a.

[0065] As an example, if the frequency of the vertically incident wave is 5.8 GHz, and it is necessary to deflect this incident wave to a -30° direction, the phase gradient distribution of the metasurface array 2 can be calculated according to the generalized Snell's law, as shown in the figure. Figure 6 As shown, Figure 6Each phase is mapped to a quantization code, and the four metasurface units of this embodiment are arranged according to the quantization code to obtain metasurface array 2. Among them, the first metasurface unit 21 is a compact square planar structure with a unit side length of 25mm and a metal layer thickness of 0.01mm. A first central radiating patch 211 is set at the geometric center of the upper surface of the first metasurface unit 21, and the first central radiating patch 211 is coincident with the geometric center of the first metasurface unit 21. Based on the vertical incident wave frequency of 5.8GHz, the outer contour side length of the central radiating patch is calculated to be in the range of 13mm to 18mm, and the inner contour size is determined by optimization through electromagnetic simulation software. The arm width of each phase control module ranges from 0.6mm to 1mm. The arm length of each phase control module is determined by the discrete phase corresponding to the metasurface unit. That is, while maintaining a compact and innovative design and easy deployment, the larger the discrete phase corresponding to the code, the longer the total arm length of the phase control module of the corresponding metasurface unit. Taking the fourth metasurface unit as an example, the fourth metasurface unit quantizes a phase of (225°, 315°], which is larger than the phase quantized by the other three metasurface units (the (315°, 360°) quantized by the first metasurface unit is equivalent to (-45°, 0°)). Therefore, the total arm length of the phase control module of the fourth metasurface unit is the longest. In order to maintain a compact and innovative design, the arm length is increased by increasing the number of phase control arms. The total arm length of each phase control module has an effective discrete phase response within the design value of ±0.4mm. The first central radiating patch 211 is a square ring structure with a thickness of 0.01mm, an outer contour side length of 14mm, and an inner contour side length of 3mm. The first phase The control module 212 and the second phase control module 213 are respectively located on the side corresponding to the preset beam deflection direction, that is, connected to the left and lower edges of the first central radiating patch 211; the first phase control module 212 and the second phase control module 213 adopt a bent structure; the first horizontal phase control arm 212a extends horizontally to the left, with an arm length of 4.5mm and an arm width of 0.8mm, and its right end is connected to the left edge of the first central radiating patch 211; the first vertical phase control arm 212b extends vertically... The first longitudinal phase control arm 212a extends downwards with an arm length of 5.7 mm and an arm width of 0.8 mm, and its upper end is connected to the left end of the first transverse phase control arm 212a. The second longitudinal phase control arm 213b extends vertically downwards with an arm length of 4.5 mm and an arm width of 0.8 mm, and its upper end is connected to the lower edge of the first central radiating patch 211. The second transverse phase control arm 213a extends horizontally to the right with an arm length of 5.7 mm and an arm width of 0.8 mm, and its left end is connected to the lower end of the second longitudinal phase control arm 213b.

[0066] It should be noted that the phase modulation module in this scheme evolved from a microstrip feed line, so its linewidth, i.e., arm width, directly affects impedance matching. The arm width of this invention comprehensively considers dielectric material, dielectric thickness, quantization phase, etc., and the optimized result is 0.6mm-1mm. Within this range, the impedance matching performance of the metasurface unit is relatively good. The arm length of the phase modulation module is related to the magnitude of the quantized phase. The larger the phase delay, the longer the arm length. Specifically, with a phase delay of 90°, the total arm length of all metasurface units is theoretically one-quarter of the waveguide wavelength; with a delay of 180°, it is theoretically half the waveguide wavelength, and so on. However, in practice, optimization is required, and the optimized result is 10mm-21mm.

[0067] like Figure 3 As shown, the second metasurface unit 22 includes a second central radiating patch 221, a third phase modulation module 222, and a fourth phase modulation module 223. The third phase modulation module 222 includes a third lateral phase modulation arm 222a and a third longitudinal phase modulation arm 222b. The right end of the third lateral phase modulation arm 222a is connected to the left edge of the second central radiating patch 221 and extends horizontally to the left. The upper end of the third longitudinal phase modulation arm 222b is connected to the left end of the third lateral phase modulation arm 222a and extends vertically downward. The fourth phase modulation module 223... It includes a fourth longitudinal phase control arm 223b and a fourth transverse phase control arm 223a. The upper end of the fourth longitudinal phase control arm 223b is connected to the lower edge of the second central radiating patch 221 and extends vertically downward. The left end of the fourth transverse phase control arm 223a is connected to the lower end of the fourth longitudinal phase control arm 223b and extends horizontally to the right. The length of the third transverse phase control arm 222a is the same as the length of the fourth longitudinal phase control arm 223b, and the length of the third longitudinal phase control arm 222b is the same as the length of the fourth transverse phase control arm 223a.

[0068] Taking the aforementioned 5.8GHz vertical incident wave frequency as an example, the second metasurface unit 22 is a compact square planar structure with a unit side length of 25mm and a metal layer thickness of 0.01mm. A second central radiating patch 221 is disposed at the geometric center of the upper surface of the second metasurface unit 22, and the second central radiating patch 221 coincides with the geometric center of the second metasurface unit 22. The second central radiating patch 221 is a square ring structure with a thickness of 0.01mm, an outer contour side length of 14mm, and an inner contour side length of 3mm. To suppress electromagnetic coupling between adjacent metasurface units and ensure the accuracy of electromagnetic beam deflection, the third phase control module 222 and the fourth phase control module 223 are respectively connected to the left and lower edges of the second central radiating patch 221. The third lateral phase control arm 222a extends horizontally to the left, with an arm length of 4.5mm and an arm width of 0.8mm, and its right end is connected to the left edge of the second central radiating patch 221. The third longitudinal phase control arm 222b extends vertically downward, with an arm length of 8.75 mm and an arm width of 0.8 mm. Its upper end is connected to the left end of the third transverse phase control arm 222a. The fourth longitudinal phase control arm 223b extends vertically downward, with an arm length of 4.5 mm and an arm width of 0.8 mm. Its upper end is connected to the lower edge of the second central radiating patch 221. The fourth transverse phase control arm 223a extends horizontally to the right, with an arm length of 8.75 mm and an arm width of 0.8 mm. Its left end is connected to the lower end of the fourth longitudinal phase control arm 223b.

[0069] like Figure 4As shown, the third metasurface unit 23 includes a third central radiating patch 231, a fifth phase control module 232, and a sixth phase control module 233. The fifth phase control module 232 includes a fifth lateral phase control arm 232a, a fifth longitudinal phase control arm 232b, and a fifth auxiliary phase control arm 232c. The right end of the fifth lateral phase control arm 232a is connected to the left edge of the third central radiating patch 231 and extends horizontally to the left. The upper end of the fifth longitudinal phase control arm 232b is connected to the left end of the fifth lateral phase control arm 232a and extends vertically downward. The left end of the fifth auxiliary phase control arm 232c is connected to the lower end of the fifth longitudinal phase control arm 232b and extends horizontally to the right. The sixth phase control module 233 includes a sixth longitudinal phase control arm 233b, a sixth... The upper end of the sixth longitudinal phase control arm 233b is connected to the lower edge of the third central radiating patch 231 and extends vertically downwards. The left end of the sixth transverse phase control arm 233a is connected to the lower end of the sixth longitudinal phase control arm 233b and extends horizontally to the right. The lower end of the sixth auxiliary phase control arm 233c is connected to the right end of the sixth transverse phase control arm 233a and extends vertically upwards. The length of the fifth transverse phase control arm 232a is the same as that of the sixth longitudinal phase control arm 233b, the length of the fifth longitudinal phase control arm 232b is the same as that of the sixth transverse phase control arm 233a, and the lengths of the fifth auxiliary phase control arm 232c and the sixth auxiliary phase control arm 233c are the same.

[0070] Taking the aforementioned 5.8GHz vertical incident wave frequency as an example, the third metasurface unit 23 is a compact square planar structure with a unit side length of 25mm and a metal layer thickness of 0.01mm. A third central radiating patch 231 is positioned at the geometric center of the upper surface of the third metasurface unit 23, and the third central radiating patch 231 coincides with the geometric center of the third metasurface unit 23. The third central radiating patch 231 is a square annular structure with a thickness of 0.01mm, an outer contour side length of 14mm, and an inner contour side length of 3mm. Similarly, the fifth phase control module 232 and the sixth phase control module 233 are respectively connected to the left and lower edges of the third central radiating patch 231, and both are bent structures. The fifth horizontal phase control arm 232a extends horizontally to the left, with an arm length of 4.5mm and an arm width of 0.8mm, and its right end is connected to the left edge of the third central radiating patch 231. The fifth vertical phase control arm... 232b extends vertically downwards, with an arm length of 10.5 mm and an arm width of 0.8 mm. Its upper end connects to the left end of the fifth transverse phase control arm 232a. The fifth auxiliary phase control arm 232c extends horizontally to the right, with an arm length of 0.75 mm and an arm width of 0.8 mm. Its left end connects to the lower end of the fifth longitudinal phase control arm 232b. The sixth longitudinal phase control arm 233b extends vertically downwards, with an arm length of 4.5 mm and an arm width of 0.8 mm. The sixth transverse phase control arm 233a extends horizontally to the right, with an arm length of 10.5 mm and an arm width of 0.8 mm. Its left end is connected to the lower end of the sixth longitudinal phase control arm 233b. The sixth auxiliary phase control arm 233c extends vertically upward, with an arm length of 0.75 mm and an arm width of 0.8 mm. Its lower end is connected to the right end of the sixth transverse phase control arm 233a.

[0071] like Figure 5As shown, the fourth metasurface unit 24 includes a fourth central radiating patch 241, a seventh phase control module 242, and an eighth phase control module 243. The seventh phase control module 242 includes a seventh lateral phase control arm 242a, a seventh longitudinal phase control arm 242b, and a seventh auxiliary phase control arm 242c. The right end of the seventh lateral phase control arm 242a is connected to the left edge of the fourth central radiating patch 241 and extends horizontally to the left. The upper end of the seventh longitudinal phase control arm 242b is connected to the left end of the seventh lateral phase control arm 242a and extends vertically downward. The left end of the seventh auxiliary phase control arm 242c is connected to the lower end of the seventh longitudinal phase control arm 242b and extends horizontally to the right. The eighth phase control module 243 includes an eighth longitudinal phase control arm 243b, an eighth... The upper end of the eighth longitudinal phase control arm 243b is connected to the lower edge of the fourth central radiation patch 241 and extends vertically downward; the left end of the eighth transverse phase control arm 243a is connected to the lower end of the eighth longitudinal phase control arm 243b and extends horizontally to the right; the lower end of the eighth auxiliary phase control arm 243c is connected to the right end of the eighth transverse phase control arm 243a and extends vertically upward; the arm length of the seventh transverse phase control arm 242a is the same as the arm length of the eighth longitudinal phase control arm 243b, the arm length of the seventh longitudinal phase control arm 242b is the same as the arm length of the eighth transverse phase control arm 243a, and the arm length of the seventh auxiliary phase control arm 242c is the same as the arm length of the eighth auxiliary phase control arm 243c.

[0072] As one implementation, the lengths of the first lateral phase control arm 212a, the third lateral phase control arm 222a, the fifth lateral phase control arm 232a, and the seventh lateral phase control arm 242a are all the same. The length of the first longitudinal phase control arm 212b is less than the length of the third longitudinal phase control arm 222b. The length of the third longitudinal phase control arm 222b is less than the length of the fifth longitudinal phase control arm 232b. The length of the fifth longitudinal phase control arm 232b is the same as the length of the seventh longitudinal phase control arm 242b. The length of the eighth auxiliary phase control arm 243c is greater than the length of the fifth auxiliary phase control arm 232c.

[0073] Taking the aforementioned 5.8GHz vertical incident wave frequency as an example, the fourth metasurface unit 24 is a square planar structure with a unit side length of 25mm and a metal layer thickness of 0.01mm. A fourth central radiating patch 241 is disposed at the geometric center of the upper surface of the fourth metasurface unit 24, and the fourth central radiating patch 241 is coincident with the geometric center of the fourth metasurface unit 24. The fourth central radiating patch 241 is a compact square ring structure with a thickness of 0.01mm, an outer contour side length of 14mm, and an inner contour side length of 3mm. Similarly, the seventh phase control module 242 and the eighth phase control module 243 are respectively connected to the left and lower edges of the fourth central radiating patch 241; and both are bent structures; the seventh transverse phase control arm 242a extends horizontally to the left, with an arm length of 4.5mm and an arm width of 0.8mm, and its right end is connected to the left edge of the fourth central radiating patch 241; the seventh longitudinal phase control arm 242b extends vertically downward, with an arm length of 10.5mm and an arm width of 0.8mm, and its upper end is connected to the left end of the seventh transverse phase control arm 242a; the seventh auxiliary phase control arm 242c extends horizontally to the right, with an arm length of 5.9mm and an arm width of 0.8mm. The eighth longitudinal phase control arm 243b has a width of 0.8 mm and its left end is connected to the lower end of the seventh longitudinal phase control arm 242b; the eighth longitudinal phase control arm 243b extends vertically downward, with an arm length of 4.5 mm and an arm width of 0.8 mm, and its upper end is connected to the lower edge of the fourth central radiation patch 241; the eighth transverse phase control arm 243a extends horizontally to the right, with an arm length of 10.5 mm and an arm width of 0.8 mm, and its left end is connected to the lower end of the eighth longitudinal phase control arm 243b; the eighth auxiliary phase control arm 243c extends vertically upward, with an arm length of 5.9 mm and an arm width of 0.8 mm, and its lower end is connected to the right end of the eighth transverse phase control arm 243a.

[0074] The technical effects of the present invention will be further explained below with reference to simulation results.

[0075] The above example was simulated using the commercial simulation software MATLAB and HFSS. The simulation content included:

[0076] Simulation 1: The phase gradient distribution of each metasurface unit is calculated according to the generalized Snell's law when the vertical incident wave is tuned to ±30° of the normal.

[0077] Simulation 2: Under 5.8 GHz vertical incidence conditions, the beam control performance of a beam-converging metasurface is simulated. The normalized E-plane radiation pattern generated by the simulation is shown below. Figure 7 As shown, from Figure 7As can be seen, the beam-converging metasurface generated in this example successfully modulates the vertically incident wave to the ±30° direction of the normal; the radar cross section (RCS) in the +30° direction of the normal is significantly enhanced to 17.6 dB, and the radar cross section in the -30° direction of the normal is increased to 10 dB.

[0078] Simulation 3 simulates the beam control performance of the beam-focusing metasurface when the incident wave is 5.8 GHz and perpendicular to it. The resulting three-dimensional radiation pattern is shown in Figure 3. Figure 8 As shown, from Figure 8 It can be seen that the scattered energy is mainly concentrated in the conical region with a normal angle of ±30°, which is highly consistent with the two-dimensional results of Simulation 1 and meets the design expectations.

[0079] In the foregoing descriptions of the embodiments, the terms "some embodiments," "examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0081] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A beam-converging metasurface, characterized in that, The device includes a dielectric substrate, a metasurface array printed on the upper surface of the dielectric substrate, and a metal ground plane disposed on the lower surface of the dielectric substrate. The metasurface array is composed of a periodic array of multiple metasurface units with different encodings and different discrete phase responses obtained according to the target beam deflection angle. A phase gradient distribution that conforms to the generalized Snell's law is formed between adjacent metasurface units, so that the energy of the incident electromagnetic wave is focused along the target direction after being reflected by the metasurface array. The metasurface unit includes a central radiating patch and a phase control module connected thereto. The phase control module includes a phase control arm composed of microstrip feed lines. The total length of the phase control arm is determined by the discrete phase response of the metasurface unit.

2. The beam-converging metasurface according to claim 1, characterized in that, The metasurface unit includes two phase control modules, which are connected to the side of the central radiating patch corresponding to the preset beam deflection direction; the connection directions of the phase control modules of the various metasurface units and the central radiating patch are all consistent.

3. The beam-converging metasurface according to claim 1, characterized in that, All phase control arms adopt a bent structure.

4. The beam-converging metasurface according to claim 1, characterized in that, All of the various metasurface units are compact square planar structures, and the central radiating patch is a square ring structure. The length of the side of the square ring structure is determined by the frequency of the incident wave from the target. The center of the central radiating patch coincides with the geometric center of the metasurface unit.

5. A beam-converging metasurface according to claim 1, characterized in that, The various metasurface units include a first metasurface unit, a second metasurface unit, a third metasurface unit, and a fourth metasurface unit. The first metasurface unit is used for discrete phase response in the phase ranges of (315°, 360°] and (0°, 45°], the second metasurface unit is used for discrete phase response in the phase range of (45°, 135°], the third metasurface unit is used for discrete phase response in the phase range of (135°, 225°], and the fourth metasurface unit is used for discrete phase response in the phase range of (225°, 315°). The phase modulation modules of the first metasurface unit and the second metasurface unit both include a bent structure composed of two phase modulation arms; The phase control modules of the third metasurface unit and the fourth metasurface unit both include a bent structure composed of three phase control arms; The outer contour side length of the central radiating patch ranges from 13mm to 18mm, the arm width of the phase control arm ranges from 0.6mm to 1mm, and the side lengths of the first metasurface unit, the second metasurface unit, the third metasurface unit, and the fourth metasurface unit all range from 24mm to 26mm.

6. A beam-converging metasurface according to claim 5, characterized in that, The first metasurface unit includes a first central radiating patch, a first phase modulation module, and a second phase modulation module; The first phase control module includes a first horizontal phase control arm and a first vertical phase control arm. The right end of the first horizontal phase control arm is connected to the left edge of the first central radiating patch and extends horizontally to the left. The upper end of the first vertical phase control arm is connected to the left end of the first horizontal phase control arm and extends vertically downward. The second phase control module includes a second longitudinal phase control arm and a second transverse phase control arm. The upper end of the second longitudinal phase control arm is connected to the lower edge of the first central radiating patch and extends vertically downward. The left end of the second transverse phase control arm is connected to the lower end of the second longitudinal phase control arm and extends horizontally to the right. The length of the first lateral phase control arm is the same as the length of the second longitudinal phase control arm, and the length of the first longitudinal phase control arm is the same as the length of the second lateral phase control arm.

7. A beam-converging metasurface according to claim 6, characterized in that, The second metasurface unit includes a second central radiating patch, a third phase modulation module, and a fourth phase modulation module; The third phase control module includes a third horizontal phase control arm and a third vertical phase control arm. The right end of the third horizontal phase control arm is connected to the left edge of the second central radiating patch and extends horizontally to the left. The upper end of the third vertical phase control arm is connected to the left end of the third horizontal phase control arm and extends vertically downward. The fourth phase control module includes a fourth longitudinal phase control arm and a fourth transverse phase control arm. The upper end of the fourth longitudinal phase control arm is connected to the lower edge of the second central radiating patch and extends vertically downward. The left end of the fourth transverse phase control arm is connected to the lower end of the fourth longitudinal phase control arm and extends horizontally to the right. The length of the third lateral phase control arm is the same as the length of the fourth longitudinal phase control arm, and the length of the third longitudinal phase control arm is the same as the length of the fourth lateral phase control arm.

8. A beam-converging metasurface according to claim 7, characterized in that, The third metasurface unit includes a third central radiating patch, a fifth phase modulation module, and a sixth phase modulation module. The fifth phase control module includes a fifth horizontal phase control arm, a fifth vertical phase control arm, and a fifth auxiliary phase control arm. The right end of the fifth horizontal phase control arm is connected to the left edge of the third central radiating patch and extends horizontally to the left. The upper end of the fifth vertical phase control arm is connected to the left end of the fifth horizontal phase control arm and extends vertically downward. The left end of the fifth auxiliary phase control arm is connected to the lower end of the fifth vertical phase control arm and extends horizontally to the right. The sixth phase control module includes a sixth longitudinal phase control arm, a sixth transverse phase control arm, and a sixth auxiliary phase control arm. The upper end of the sixth longitudinal phase control arm is connected to the lower edge of the third central radiating patch and extends vertically downward. The left end of the sixth transverse phase control arm is connected to the lower end of the sixth longitudinal phase control arm and extends horizontally to the right. The lower end of the sixth auxiliary phase control arm is connected to the right end of the sixth transverse phase control arm and extends vertically upward. The length of the fifth lateral phase control arm is the same as the length of the sixth longitudinal phase control arm, the length of the fifth longitudinal phase control arm is the same as the length of the sixth lateral phase control arm, and the length of the fifth auxiliary phase control arm is the same as the length of the sixth auxiliary phase control arm.

9. A beam-converging metasurface according to claim 8, characterized in that, The fourth metasurface unit includes a fourth central radiating patch, a seventh phase modulation module, and an eighth phase modulation module. The seventh phase control module includes a seventh horizontal phase control arm, a seventh vertical phase control arm, and a seventh auxiliary phase control arm. The right end of the seventh horizontal phase control arm is connected to the left edge of the fourth central radiating patch and extends horizontally to the left. The upper end of the seventh vertical phase control arm is connected to the left end of the seventh horizontal phase control arm and extends vertically downward. The left end of the seventh auxiliary phase control arm is connected to the lower end of the seventh vertical phase control arm and extends horizontally to the right. The eighth phase control module includes an eighth longitudinal phase control arm, an eighth transverse phase control arm, and an eighth auxiliary phase control arm. The upper end of the eighth longitudinal phase control arm is connected to the lower edge of the fourth central radiating patch and extends vertically downward. The left end of the eighth transverse phase control arm is connected to the lower end of the eighth longitudinal phase control arm and extends horizontally to the right. The lower end of the eighth auxiliary phase control arm is connected to the right end of the eighth transverse phase control arm and extends vertically upward. The length of the seventh lateral phase control arm is the same as the length of the eighth longitudinal phase control arm, the length of the seventh longitudinal phase control arm is the same as the length of the eighth lateral phase control arm, and the length of the seventh auxiliary phase control arm is the same as the length of the eighth auxiliary phase control arm.

10. A beam-converging metasurface according to claim 9, characterized in that, The lengths of the first, third, fifth, and seventh lateral phase control arms are all the same. The length of the first longitudinal phase control arm is less than that of the third longitudinal phase control arm. The length of the third longitudinal phase control arm is less than that of the fifth longitudinal phase control arm. The length of the fifth longitudinal phase control arm is the same as that of the seventh longitudinal phase control arm. The length of the eighth auxiliary phase control arm is greater than that of the fifth auxiliary phase control arm.

Images