Transmission metasurface multi-subarray beam forming method and device

Abstract

The invention provides a transmission metasurface multi-subarray beam forming method and device. The device comprises a support used for supporting, a subarray type transmission metasurface module used for transmitting electromagnetic waves and achieving beam forming, a multi-feed-source antenna module used for radiating the electromagnetic waves and a multi-feed-source control module used for wavefront modulation. Through the multi-feed-source control module, the consistency of the amplitude and the phase of signals input into the horn antenna unit is achieved, the whole array is formed by splicing the transmission metasurface subarrays in the same arrangement, meanwhile, the subarrays correspond to horn antennas of the multi-feed-source antenna module in a one-to-one mode, system beam forming is achieved, and the directivity and the quality of beams are remarkably improved. According to the embodiment of the invention, multi-feed-source radiation energy is converged by using a joint subarray idea, the signal transmission intensity of the transmission metasurface is improved, and wavefront regulation and beam forming with higher gain can be realized at a 10GHz frequency.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, in particular to a metasurface system, to the field of artificial electromagnetic material technology, and specifically to a transmission metasurface multi-subarray beamforming system. Background Art

[0002] A metasurface is a two-dimensional artificial structure whose unit size is much smaller than the working wavelength. By designing structural units of subwavelength size, metamaterials can adjust the characteristics of electromagnetic waves within a wider frequency band, thereby realizing the manipulation of the phase, amplitude and polarization of electromagnetic waves in different frequency bands. Therefore, metasurfaces are widely used in the design of devices with special functions such as lenses, antennas and radar covers, and have wide applications in communications, imaging and optical information processing.

[0003] Transmissive metasurface is an important branch of metasurface. Its main function is to achieve precise control of electromagnetic wave transmission by designing specific two-dimensional structural units. Transmissive metasurface can effectively regulate the phase distribution of transmitted waves in a compact form, so that it can be used for efficient wavefront shaping. In practical applications, it can replace traditional heavy optical lenses and act as an ultra-thin lens to achieve lightweight beam focusing and shaping. This type of lens is widely used in optical imaging systems, antenna design and radar systems.

[0004] Although transmissive metasurfaces have shown great application potential in many fields, they still face the challenge of low gain in some practical applications, which limits their promotion. The main problem is that their energy focusing ability is low. Insufficient gain means low radiation efficiency and weak signal transmission intensity. In scenarios requiring high gain such as long-distance communication and directional imaging, the performance of transmissive metasurfaces needs to be further optimized. Compared with traditional lenses or high-gain antennas, its gain level still has room for improvement. Summary of the invention

[0005] The purpose of the present invention is to provide a transmissive metasurface multi-subarray beamforming method and device, which can improve the signal transmission strength of the transmissive metasurface by converging the radiation energy of multiple feed sources through the concept of joint subarrays, and can achieve higher gain wavefront control and beam synthesis at a frequency of 10 GHz. The specific technical solution is as follows:

[0006] A transmission metasurface multi-subarray beamforming method and device. The system of the invention comprises a bracket for supporting.

[0007] The system includes a sub-array transmissive metasurface mounted on a bracket and used for transmitting electromagnetic waves.

[0008] The system includes a plurality of feed sources mounted on a bracket and used for emitting electromagnetic waves.

[0009] The system includes a multi-feed control module which is installed on a bracket and used for controlling the radiation of the multi-feeds.

[0010] Wherein, the multi-feed control module and the multi-feed are electrically connected one by one.

[0011] The sub-array transmission metasurface is vertically installed on one side of the bracket, and the multi-feed control module and the multi-feed are installed on the other side of the bracket. The multi-feed is perpendicular to the sub-array transmission metasurface and always has the same orientation as the sub-array transmission metasurface.

[0012] The sub-array transmission metasurface is composed of sub-array modules with the same arrangement spliced ​​together to form a whole array. The sub-array of the transmission metasurface is a rectangular array structure composed of a number of transmission units arranged periodically and evenly spaced in a plane. The splicing method of the whole array is a structure composed of sub-arrays freely combined in a plane, without any specific shape restrictions.

[0013] Optionally, the transmission metasurface subarray structure includes: three intermediate dielectric layers and four metal layers, wherein the dielectric layers and the metal layers are alternately stacked, the dielectric layers are F4B polytetrafluoroethylene high-frequency material, the relative dielectric constant is 2.65, and the loss tangent is 0.001; the metal layer is composed of M×N metal patch units arranged in an array, and each metal iron sheet is composed of two parts, including a square ring at the edge and a quasi-snow spot shape at the center;

[0014] Optionally, the width of the square ring is m, and the boundary distance is 0 mm; the quasi-snow spot shape is a rectangle with a length of L and a width of W, which is etched by rotation at the center of the original; the optional range of L of the quasi-snow spot shape varies from 1 mm to 9 mm; by changing the length L of the quasi-snow spot shape, 360° continuous transmission phase regulation can be achieved;

[0015] Optionally, the sub-array of the transmission metasurface is a rectangular array structure composed of a number of high-transmittance phase modulation units arranged periodically and at equal intervals in a plane. The array arrangement of multiple transmission units is determined based on the generalized Snell's law, and the expected compensation phase distribution of the array element at the array element position (x, y) in the array is:

[0016]

[0017] Where k0 = 2π / λ0 is the free space wave number at the design frequency, θ0 is the beam deflection angle along the z-axis, the position is (x0, y0), r is the axial distance of the target beam deflection, and the distance between the feed and the metasurface is F.

[0018] Optionally, the splicing method of the entire array is a structure composed of sub-arrays freely combined in a plane, which means that the sub-array transmission supersurface is composed of multiple completely identical transmission supersurface sub-arrays seamlessly spliced ​​together. The splicing method is determined by the requirements of the specific embodiment, and does not limit the number of sub-arrays and the shape of the entire array combination.

[0019] The multiple feed sources for emitting electromagnetic waves are located on one side of the transmission metasurface module. The unit structure of the multiple feed sources is composed of horn antennas. Each horn antenna corresponds to a transmission metasurface subarray. The height of the initial point of the horn antenna equivalent phase coincides with the preset focal height of the metasurface subarray. By collectively moving the positions of the horn antennas, synthetic beams with different deflection angles can be generated.

[0020] The multi-feed control module for controlling multi-feed radiation refers to a device that can realize wavefront modulation, optimize the signal transmission path, and ensure the consistency of the amplitude and phase of each input horn antenna unit signal. The module includes a signal transmission circuit, a phase shift circuit, an amplification circuit and a power division circuit. By precisely controlling the input signal of each feed, the horn antenna can produce the expected radiation beam shape, while reducing signal interference and phase error, thereby improving the system's directivity, gain and overall radiation performance.

[0021] Beneficial Effects

[0022] The present invention provides a transmissive metasurface multi-subarray beamforming method and device. Through the combination of multi-feed design and sub-array transmissive metasurface, the device can effectively enhance the beam gain of the system, so that the electromagnetic energy can be better concentrated in a specific direction. By precisely controlling the modulation characteristics of the transmissive metasurface, high-precision control of the beam morphology can be achieved, beam distortion and sidelobe effects can be reduced, and the directivity and quality of the beam can be significantly improved.

[0023] The system of the present invention has the advantages of low profile, low cost, high precision and rapid adjustment, and can be widely used in the field of 6G communication services for multiple users. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of a transmission metasurface multi-subarray beamforming method and device of the present invention;

[0025] Figure 2 It is a schematic diagram of another viewing angle of a transmission metasurface multi-subarray beamforming method and device structure of the present invention;

[0026] Figure 3 is a schematic diagram of the structure of a sub-array transmission metasurface array according to an embodiment of the present invention;

[0027] Figure 4 is a top-level structural diagram and a side view schematic diagram of a transmission unit according to an embodiment of the present invention;

[0028] Figure 5 4 is a diagram showing the correspondence between the geometric parameter L of the transmission unit and the output phase distribution for realizing 4-bit transmission phase modulation according to an embodiment of the present invention;

[0029] Figure 6 is a schematic diagram of the structure of a horn antenna according to an embodiment of the present invention;

[0030] Figure 7 is a structural block diagram of a multi-feed control module according to an embodiment of the present invention;

[0031] Figure 8 It is a three-dimensional pattern of a vertical front beam generated at 10 GHz in an experimental test of a multi-feed auxiliary sub-array transmission metasurface system according to an embodiment of the present invention;

[0032] Fig. 9 This is a beam scanning comparison diagram of a multi-feed auxiliary sub-array transmission metasurface system in an embodiment of the present invention and a single sub-array combined with a single horn antenna to generate a vertical array beam;

[0033] In the figure: 1. Sub-array transmission metasurface module, 2. Multi-feed antenna module, 3. Multi-feed control module, 4. Bracket, 5. Transmission metasurface sub-array, 6. Transmission unit, 7. Dielectric layer, 8. Quasi-snow spot metal layer, 9. Square ring metal layer, 10. Horn antenna, 11. Signal transmission circuit, 12. Phase shift circuit, 13. Amplification circuit, 14. Power division circuit. DETAILED DESCRIPTION

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0035] The present invention is further described below in conjunction with the accompanying drawings, and the protection scope of the present invention is not limited to the following:

[0036] The embodiment of the present invention provides a transmission metasurface multi-subarray beamforming method and device, such as Figure 1 and Figure 2As shown, the multi-feed assisted sub-array transmission metasurface synthetic beam generation system of the present invention includes a sub-array transmission metasurface module 1 for transmitting electromagnetic waves and realizing beamforming, a multi-feed antenna module 2 for radiating electromagnetic waves, a multi-feed control module 3 for wavefront modulation, optimizing the signal transmission path, and ensuring the consistency of the amplitude and phase of each input horn antenna unit signal, and a bracket 4 for support.

[0037] like Figure 1 As shown, the sub-array transmission metasurface module 1 is vertically installed on one side of the bracket 4, facing the signal receiving end. Depending on the actual application scenario, the multi-feed antenna module 2 is vertically installed on the other side of the bracket 4, and the direction needs to always be perpendicular to the array surface of the sub-array transmission metasurface module 1 to ensure that the equally spaced transmission units 6 arranged according to the generalized Snell's law can provide accurate phase compensation. The multi-feed antenna module 2 is electrically connected one by one with the multi-feed control module 3.

[0038] During specific implementation, the bracket 4 is specifically composed of two transparent acrylic plates and four connecting support structures. The two transparent acrylic plates are respectively used to fix the sub-array transmission metasurface module 1 and the multi-feed antenna module 2 to ensure that the height of the initial point of the horn antenna equivalent phase coincides with the preset focal height of the metasurface sub-array. The four connecting support structures are used to adjust the system profile height. There are four symmetrical groups of horn antenna holes on the transparent acrylic plate that fixes the multi-feed antenna module 2, which are used to provide the horn antenna with the same distance of the corresponding focal point offset to achieve target beam deflection.

[0039] like Figure 3 As shown, the sub-array type transmission metasurface is composed of sub-array modules with the same arrangement to form a whole array. In the embodiment of the present invention, the sub-array type transmission metasurface module 1 is a rectangular structure composed of four transmission metasurface sub-arrays 5 with the same arrangement and arranged at equal intervals in a plane.

[0040] In a specific implementation, the transmission metasurface subarray 5 is composed of three intermediate dielectric layers 7 and four metal layers alternately stacked, wherein the dielectric layer 7 and the metal layer are alternately stacked, the dielectric layer is F4B polytetrafluoroethylene high-frequency material, with a relative dielectric constant of 2.65, a loss tangent of 0.001, and a height of H1=15 mm; the metal layer is composed of 16×16 metal patch units arranged in an array, and each metal patch unit is composed of two parts, including a square circular ring metal layer 9 located at the edge and a quasi-snow spot metal layer 8 located in the center;

[0041] In specific implementation, the width m of the square ring metal layer 9 is 0.2 mm, and the boundary distance is 0 mm; the quasi-snow spot metal layer 8 is a rectangle with a length of L and a width of W=3 mm, which is rotated and etched in the center of the original; the optional range of L of the quasi-snow spot metal layer 8 varies from 1 mm to 9 mm, and each metal patch corresponds to a transmission unit 6. The modulation phase of the transmission unit 6 is determined by the generalized Snell's law. The expected compensation phase distribution of the array element with the array element position (x, y) in the array is:

[0042]

[0043] Where k0 = 2π / λ0 is the free space wave number at the design frequency, θ0 is the beam deflection angle along the z-axis, the position is (x0, y0), r is the axial distance of the target beam deflection, and the distance between the feed and the metasurface is F.

[0044] In the specific implementation, the transmission metasurface subarray 5 adopts 4-bit transmission phase modulation, the size of the transmission unit 6 is set to the unit side length length = 10 mm, the center of the subarray transmission metasurface is located at the origin of the three-dimensional Cartesian coordinate system, and the structural parameters and modulation phase correspondence of the transmission unit 6 in 16 states are obtained as follows: Figure 5 As shown, the four layers of quasi-snow spot metal layers 8 and the four layers of square ring metal layers 9 of each transmission unit 6 are designed to be consistent.

[0045] like Figure 6 As shown, the multi-feed antenna module 2 unit is composed of horn antennas 10, the number of horn antennas 10 is consistent with the number of transmission metasurface subarrays 5, the height of the initial point of the equivalent phase of the four horn antennas 10 coincides with the preset focus height of the transmission metasurface subarray 5, and the structural parameters of the horn antenna 10 include: horn aperture surface length l y =47mm, width l x =37mm, waveguide aperture length d y =25.4mm, width d x =12.7mm, waveguide height d h =55mm, speaker height l h =10mm, feed offset waveguide bottom Δ=7.5mm;

[0046] When implementing it, Figure 1 As shown, the horn antenna 10 is fixed on the acrylic plate on one side of the bracket 4, and four connecting support structures are used to adjust the system profile height. The horn antenna 10 can be collectively moved by selecting the hole position of the transparent acrylic plate of the bracket 4, and the direction deflection of the system synthetic beam is achieved by offsetting the focal position of the horn antenna feed source.

[0047] like Figure 7As shown, the structure of the multi-feed control module 3 is composed of a signal transmission circuit 11, a plurality of phase shift circuits 12, an amplifier circuit 13 and a power division circuit 14. The signal excitation in the feed control module 3 is input by the signal transmission circuit 11, and input to the input end of the phase shift circuit 12. The output end of the phase shift circuit 12 is connected to the input end of the amplifier circuit 13, the output end of the amplifier circuit 13 is connected to the input end of the power division circuit 14, and the output end of the power division circuit 14 is connected to each horn antenna 10 of the multi-feed antenna module 2. The signal is digitally controlled to realize wavefront modulation, and then output from the horn antenna 10 after ensuring the consistency of the amplitude and phase of each input horn antenna unit signal.

[0048] like Figure 8 As shown, the vertical array beam generated at 10 GHz in the experimental test of the multi-feed assisted sub-array transmission metasurface system of an embodiment of the present invention. According to the three-dimensional radiation diagram, it can be seen that the embodiment of the present invention realizes the beam synthesis of the multi-feed assisted sub-array transmission metasurface, and the beam directivity is good.

[0049] like Fig. 9 As shown in the figure, the beam scanning diagrams of the multi-feed assisted sub-array transmission metasurface system and the single sub-array combined with a single horn antenna to generate a vertical array beam are compared. From the data, it can be seen that the multi-feed assisted sub-array transmission metasurface system based on the sub-array transmission metasurface can realize multi-sub-array beam synthesis, which improves the beam gain by at least 3dB compared to a single sub-array. Increasing the number of sub-arrays will further improve the system's synthetic beam gain.

[0050] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A transmission metasurface multi-subarray beamforming method and device, characterized in that: comprising a bracket 4 for supporting; It includes a multi-array cooperative transmission metasurface module 1 installed on a bracket 4 and used for transmitting electromagnetic waves and realizing beamforming; It includes a multi-feed antenna module 2 mounted on a bracket 4 and used for radiating electromagnetic waves; It includes a multi-feed control module 3 which is electrically connected to the multi-feed antenna module 2 one by one and is used for wavefront modulation, optimizing the signal transmission path, and ensuring the consistency of the amplitude and phase of each input horn antenna unit signal.

2. The transmission metasurface multi-subarray beamforming method and device according to claim 1, characterized in that: The bracket 4 is composed of two transparent acrylic plates and four connecting support structures. The two transparent acrylic plates are used to fix the multi-array cooperative transmission metasurface module 1 and the multi-feed antenna module 2 respectively to ensure that the height of the initial point of the horn antenna equivalent phase coincides with the preset focus height of the metasurface subarray. The four connecting support structures are used to adjust the system profile height. There are four symmetrical groups of horn antenna holes on the transparent acrylic plate that fixes the multi-feed antenna module 2, which are used to provide the horn antenna with the same distance of the corresponding focus offset to achieve target beam deflection.

3. The bracket 4 according to claim 2, characterized in that: The multi-array cooperative transmission metasurface module 1 is vertically installed on one side of the bracket 4, facing the signal receiving end. Depending on the actual application scenario, the multi-feed antenna module 2 is vertically installed on the other side of the bracket 4, and the direction needs to always be perpendicular to the array surface of the multi-array cooperative transmission metasurface module 1.

4. The transmission metasurface multi-subarray beamforming method and device according to claim 1, characterized in that: The multi-array cooperative transmission metasurface module 1 is composed of transmission metasurface sub-arrays 5 with the same arrangement spliced ​​together to form a whole array. The splicing method of the whole array is a structure composed of sub-arrays freely combined in a plane without any specific shape restrictions.

5. The transmission metasurface subarray 5 according to claim 4, characterized in that: The transmission metasurface subarray 5 is composed of three intermediate dielectric layers 7 and four metal layers alternately stacked. Each metal patch is composed of M·N metal patch units arranged in an array. The metal patch unit is composed of two parts, including a square ring metal layer 9 located at the edge and a quasi-snow spot metal layer 8 located in the center. Each metal patch corresponds to a transmission unit 6. The modulation phase of the transmission unit 6 is determined by the generalized Snell's law. The expected compensation phase distribution of the array element with the array element position (x, y) in the array is: Where k0 = 2π / λ0 is the free space wave number at the design frequency, θ0 is the beam deflection angle along the z-axis, the position is (x0, y0), r is the axial distance of the target beam deflection, and the distance between the feed and the metasurface is F.

6. The transmission metasurface multi-subarray beamforming method and device according to claim 1, characterized in that: The multi-feed antenna module 2 is composed of horn antennas 10, the number of which is consistent with the number of transmission metasurface subarrays 5. The horn antennas 10 are fixed on an acrylic plate on one side of the bracket 4. The height of the initial point of the equivalent phase coincides with the preset focal height of the transmission metasurface subarray 5. The positions can be collectively moved by selecting the hole positions of the transparent acrylic plate of the bracket 4, and the direction deflection of the system synthetic beam can be achieved by offsetting the focal position of the horn antenna feed.

7. The transmission metasurface multi-subarray beamforming method and device according to claim 1, characterized in that: The multi-feed control module 3 is composed of a signal transmission circuit 11, a plurality of phase shift circuits 12, an amplifier circuit 13 and a power division circuit 14. The signal excitation in the feed control module 3 is input by the signal transmission circuit 11 and input to the input end of the phase shift circuit 12. The output end of the phase shift circuit 12 is connected to the input end of the amplifier circuit 13, the output end of the amplifier circuit 13 is connected to the input end of the power division circuit 14, and the output end of the power division circuit 14 is connected to each horn antenna 10 of the multi-feed antenna module 2. The signal is digitally controlled to realize wavefront modulation, ensure the amplitude and phase consistency of each input horn antenna unit signal, and then be output from the horn antenna 10.

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