A millimeter-wave cylindrical conformal transmission array based on a double-layer Huygens metasurface

Abstract

This invention discloses a millimeter-wave cylindrical conformal transmission array based on a double-layer Huygens metasurface, comprising a 3D-printed overall frame, positioning holes, a horn moving frame, a waveguide-coaxial converter interface, a horn antenna, two dielectric substrates, metal structural units, a foam support layer, and a 3D-printed dielectric substrate support frame. The waveguide-coaxial converter interface (4) is mounted on the horn antenna (5) and connected to the coaxial cable required for testing. The horn antenna is embedded in the middle of the horn moving frame, which is mounted at one end of the 3D-printed frame. The two dielectric substrates are cylindrically conformal, and several metal structural units are arranged on the two dielectric substrates along the direction of the cylindrical curvature. A foam support layer is provided between the two dielectric substrates. The two dielectric substrates are fixed to the 3D-printed dielectric substrate support frame. The 3D-printed dielectric substrate support frame and the end of the 3D-printed overall frame away from the horn moving frame are fixedly connected through pre-drilled positioning holes. This invention has excellent conformal characteristics, making it a highly promising solution for airborne and missile-borne systems.

Description

TECHNICAL FIELD

[0001] The application relates to the field of metasurface applications, and in particular to a millimeter wave columnar conformal transmission array based on a double-layer Huygens metasurface. BACKGROUND

[0002] In modern communication technology, millimeter waves are widely used in 5G communication, automotive radar and imaging systems due to their high bandwidth and short wavelength. Metasurface antenna is a new microwave and optical antenna technology, and wavefront regulation of the antenna using metasurfaces is a very effective means. The metasurface is composed of a large number of subwavelength structure units, which can adjust the phase, amplitude and polarization characteristics of the wave. Compared with traditional antennas, metasurface antennas not only have smaller size and lighter weight, but also have significant advantages in radiation directivity, gain and multifunctionality.

[0003] Based on the Huygens principle, the metasurface can flexibly manipulate the phase and amplitude of the wave, thereby realizing beamforming, polarization modulation and other functions. Among them, the double-layer Huygens metasurface has greater design freedom than the single-layer structure, which can effectively improve the electromagnetic performance. However, the current research still needs to solve the problems of radiation efficiency and dynamic adaptability of millimeter wave metasurfaces. SUMMARY

[0004] The purpose of the application is to provide a millimeter wave columnar conformal transmission array based on a double-layer Huygens metasurface, which can realize good conformal effect, reduce energy loss and improve the transmission efficiency of millimeter waves.

[0005] The technical scheme for achieving the purpose of the application is as follows:

[0006] A kind of millimeter wave cylindrical surface conformal transmission array based on double-layer Huygens super surface, including 3D printing integral frame, positioning hole, horn mobile frame, waveguide coaxial converter interface, horn antenna, two layers of dielectric substrate, metal structure unit, foam support layer and 3D printing dielectric substrate support frame, the waveguide coaxial converter interface (4) is installed on horn antenna (5), with the coaxial cable needed in test, the horn antenna is embedded in horn mobile frame middle position, horn mobile frame is installed in 3D printing integral frame one end;The two layers of dielectric substrate are cylindrical surface conformal, several metal structure units are arranged on the two layers of dielectric substrate along the direction of cylindrical surface bending, foam support layer is arranged between the two layers of dielectric substrate, the two layers of dielectric substrate are fixed on 3D printing dielectric substrate support frame, and 3D printing dielectric substrate support frame and 3D printing integral frame are fixedly connected away from the one end of horn mobile frame by pre-made positioning hole.Horn antenna is used as excitation source to provide spherical wave, and Huygens super surface can realize the regulation of incident electromagnetic wave phase and amplitude, so that the whole array can effectively control the propagation direction and wave front form of electromagnetic wave while ensuring high transmission efficiency.

[0007] Preferably, the material of the 3D printing integral frame and the 3D printing dielectric substrate support frame is resin.

[0008] Preferably, the diameter of the positioning hole is 4.1 mm.

[0009] Preferably, the material of the horn mobile frame is resin.

[0010] Preferably, the waveguide coaxial converter interface (4) has a length of 7.12 mm and a width of 3.56 mm.

[0011] Preferably, the material of the horn antenna is aluminum alloy.

[0012] Preferably, the two layers of dielectric substrate are Taconic TLY with a thickness of 0.508 mm.

[0013] Preferably, the metal structure unit includes two non-intersecting I-shaped metal structures, and one I-shaped metal structure of one dielectric substrate is orthogonal to one I-shaped metal structure of the other dielectric substrate.

[0014] Preferably, the material of the metal structure unit is copper with a thickness of 0.035 mm, and the distance between the center of the conformal transmission array of the two layers of dielectric substrate and the horn antenna is 67 mm.

[0015] Preferably, the material of the foam support layer is foam with a thickness of 1.5 mm.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] (1) For the previous plane transmission array and single layer conformal transmission array, the application proposes a kind of millimeter wave cylindrical conformal transmission array based on double-layer Huygens metasurface, characterized by two layers of conformal dielectric substrate with air layer in the middle of conformal metasurface.

[0018] (2) For the problem of previous conformal transmission array thickness being too thick, the application proposes a double-layer transmission array with air layer conformal, and the air layer is replaced by foam as the support close to the upper and lower conformal dielectric substrate, so as to reduce the thickness of dielectric substrate and facilitate the realization of cylindrical conformal.

[0019] (3) For the previous conformal transmission array is not convenient to assemble, fix and test, the application proposes a kind of 3D printing overall frame and 3D printing medium substrate support frame, which can better realize the assembly and fixation of each part, so as to reduce the test error.

[0020] (4) The application has the characteristics of good conformal, conformal metasurface with excellent shape adaptability, efficient electromagnetic wave control ability, lightweight design, multi-functional integration and anti-interference ability, which becomes a very potential solution in airborne and missile-borne systems. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the unit model diagram of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application.

[0022] Figure 2 is the transmission phase shift comparison diagram of the unit of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application under different frequencies.

[0023] Figure 3 is the transmission amplitude comparison diagram of the unit of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application under different frequencies.

[0024] Figure 4 is the overall structure diagram of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application.

[0025] Figure 5 is the two-layer dielectric substrate diagram of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application.

[0026] Figure 6 is the foam support layer diagram of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application.

[0027] Figure 7 is the 3D printing overall frame diagram of the millimeter wave cylindrical conformal transmission array of double-layer Huygens metasurface of the application.

[0028] Figure 8This is a schematic diagram of the support frame for the 3D printing of the dielectric substrate of the millimeter-wave cylindrical conformal transmission array with the double-layer Huygens metasurface of the present invention.

[0029] Figure 9 This is a photograph of the actual fabrication of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of this invention.

[0030] Figure 10 This is a comparison chart of the S-parameters of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of this invention, based on simulation and testing.

[0031] Figure 11 This is a comparison of the radiation patterns from the simulation and testing of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of this invention. Figure 11 (a) The radiation pattern of the E-plane in the simulation and testing of the millimeter-wave cylindrical conformal transmission array of the present invention. Figure 11 (b) shows the radiation pattern of the H-plane in the simulation and testing of the millimeter-wave cylindrical conformal transmission array of the present invention.

[0032] Figure 12 This is a comparison of the gain curves from the simulation and testing of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of this invention. Detailed Implementation

[0033] In recent years, wavefront manipulation of antennas using metasurfaces has become a highly effective method. In millimeter-wave applications, metasurfaces are often used to control the beam in the radiation pattern. In this case, a horn is usually used as the excitation source, employing air-dielectric coupling feeding (referred to as air feeding), which has advantages such as simple feeding, high aperture efficiency, wide bandwidth, and relatively low cost. Studying Huygens metasurfaces for beam manipulation to achieve high-gain beams has become a focal point for metasurface antennas.

[0034] First, a unit model of the transmission array was constructed. By changing the length parameters of the I-shaped metal structure on the upper surface of the two dielectric substrates, the basic requirements for amplitude and phase were met, thus achieving good transmittance and phase shift coverage at the designed 30GHz frequency. The transmission phase shift ranged from -116.06° to -442.73°, with the transmission amplitude within -0.91dB within this range. The unit period parameter was optimized to a period of 7mm. Then, the phase compensation required for each unit was calculated using the conformal transmission array phase compensation principle. The required double-layer planar transmission array was designed using HFSS-MATLAB-API joint modeling, and then conformally fitted with the corresponding cylinder to obtain the desired conformal transmission array. The conformal transmission array has a size of 13×13, with energy emitted from the feed horn. The transmission array units control the electromagnetic waves by varying the length of the I-shaped metal structure, thereby converting spherical waves into plane waves.

[0035] The conformal transmission array is formed by conformally fixing two 0.508mm thick Taconic TLY planar dielectric substrates using a 3D-printed dielectric substrate support frame. An I-shaped metal structure, made of copper and 0.035mm thick, is printed on the surface of the two dielectric substrates. The conformal transmission array is fixed using a 3D-printed overall frame, a foam support layer, and a 3D-printed dielectric substrate support frame. These components are secured together with nylon screws through pre-drilled positioning holes to achieve the required curvature.

[0036] Designing a Huygens metasurface first requires studying its working principle, then exploring the resonance characteristics of the proposed Huygens unit cell. By optimizing parameters such as the unit cell period, air layer thickness, and the length and width of the I-shaped metal structure, the designed Huygens metasurface unit cell is proposed. The admittance Y of the electrode is also considered. es and the impedance Z of the magnetic sheet ms The relationship is as follows:

[0037]

[0038] In the formula, η is the intrinsic impedance of free space, R is the complex reflection coefficient, and T is the complex transmission coefficient. When the real parts of the plate admittance and the plate impedance are approximately zero, a transmission peak excited by electromagnetic resonance will be generated, satisfying the equation:

[0039] Y es η = Z ms / η

[0040] To further investigate the resonance phenomenon, we observed the current distribution on the surfaces of the two dipoles and found that they alternately generate electric and magnetic resonances, which together contribute to the Huygensterian nature of the unit cell.

[0041] Based on the phase compensation principle of conformal transmission array antennas, it is necessary to adjust the appropriate phase shift of the transmission array antenna elements at different positions on the conformal transmission array. This ensures that the electromagnetic wave emitted by the feed antenna at the focal point, after phase compensation at different elements, forms a planar phase wavefront at the aperture on the other side of the conformal transmission array. Assuming the beam direction is... θ i It is the angle between the beam and the positive z-axis. It is the angle between the projection vector of the beam onto the xoy plane and the positive x-axis. From array antenna theory, we know that the required phase distribution of the transmitted electric field is:

[0042]

[0043] Where k0 is the wave number in free space. The initial phase generated when the electromagnetic wave emitted by the feed propagates to the conformal transmission array is:

[0044]

[0045] When designing a three-dimensional transmission array, the phase distribution along both the xoy and xoz planes must be considered simultaneously. Since the coordinates of each element in the z-axis direction are inconsistent, it is necessary to compensate for the phase difference caused by the different distances at which the same planar phase wavefront is generated on the reference plane in the z-axis direction. This requires a coordinate system for each element position (x...) on the conformal transmission array. i ,y i ,z i Each of them has a specific required compensation phase:

[0046]

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] Combination Figure 4 A millimeter-wave cylindrical conformal transmission array based on a double-layer Huygens metasurface includes a 3D-printed overall frame 1, positioning holes 2, a horn moving frame 3, a waveguide-coaxial converter interface 4, a horn antenna 5, two dielectric substrates 6, metal structural units 7 on the upper surfaces of the two dielectric substrates, a foam support layer 8, and a 3D-printed dielectric substrate support frame 9. The waveguide-coaxial converter interface 4, 7.12 mm long and 3.56 mm wide, is mounted on the horn antenna 5 and connects to the coaxial cable required for actual testing. The horn antenna 5 is embedded in the middle of the horn moving frame 3, and both are then placed on the 3D-printed overall frame 1. The two dielectric substrates 6, the I-shaped metal structural units 7 attached to the upper surfaces of the two dielectric substrates, and the foam support layer 8 located between the two dielectric substrates are fixed to the 3D-printed dielectric substrate support frame 9 with nylon screws. The above parts and the 3D-printed overall frame 1 are assembled and fixed through pre-drilled positioning holes 2, thereby realizing the designed conformal transmission array. The double-layer conformal transmission array is fixed by a 3D printed overall frame and a 3D printed medium substrate support frame. A horn antenna is placed at a distance of 67mm from the center of the double-layer conformal transmission array, thus constituting the present invention.

[0050] Figure 1 This is a schematic diagram of the millimeter-wave cylindrical conformal transmission array unit model of the double-layer Huygens metasurface of the present invention, including two dielectric substrates and an I-shaped metal structure printed on the upper surface of the two dielectric substrates. Figure 1The darker color represents the I-shaped metal structure on the upper surface of the upper dielectric substrate, while the lighter color represents the I-shaped metal structure on the upper surface of the lower dielectric substrate. Two non-intersecting horizontal and vertical I-shaped metal structures are printed on the upper surface of each dielectric substrate. One I-shaped metal structure on one dielectric substrate and one I-shaped metal structure on another dielectric substrate form a cross shape, with an air layer in between, thereby reducing the thickness of the dielectric substrate and facilitating conformal cylindrical surfaces.

[0051] Figure 4 This is a schematic diagram of the overall structure of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of the present invention. The array is arranged along the direction of the curvature of the cylinder. The two-layer planar transmission array is generated by MATLAB-HFSS joint modeling, and the designed conformal transmission array is obtained by conforming with the cylinder. Figure 5 This is a schematic diagram of the two-layer dielectric substrate of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of the present invention. The two conformal dielectric substrates are placed one above the other, and an I-shaped metal structure is orthogonally placed on the surface of the two dielectric substrates. Figure 2 This is a comparison of the transmission phase shift of the millimeter-wave cylindrical conformal transmission array unit of the double-layer Huygens metasurface of the present invention at different frequencies. The transmission phase shift ranges from -116.06° to -442.73°. Figure 3 This is a comparison of the transmission amplitude of the millimeter-wave cylindrical conformal transmission array unit of the double-layer Huygens metasurface of the present invention at different frequencies. The transmission amplitude within the transmission phase shift range is all within -0.91dB.

[0052] Figure 6 This is a schematic diagram of the foam support layer of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of the present invention, with a thickness of 1.5 mm.

[0053] Figure 7 This is a schematic diagram of the overall 3D printing framework of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of the present invention. It includes a T-shaped base, on which a vertical support rod is installed. The support rod is fixedly connected to the 3D printing medium substrate support frame 9 through positioning holes. The material used is resin.

[0054] Figure 8 This is a schematic diagram of the 3D-printed dielectric substrate support frame for the millimeter-wave cylindrical conformal transmission array with a double-layer Huygens metasurface of the present invention. The material used is resin. The overall 3D-printed frame, the 3D-printed dielectric substrate support frame, the foam support layer, and the double-layer conformal dielectric substrate are assembled and fixed between layers using nylon screws.

[0055] Figure 9 This is a photograph of the actual fabricated double-layer conformal transmission array produced according to the present invention. Figure 10This is a comparison of the simulation and measured S-parameters of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of this invention. The conformal transmission array has a good reflection coefficient in the 27GHz to 31GHz frequency band. Figure 11 This is a comparison of the simulation and measured radiation patterns of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of the present invention, specifically the comparison results of the simulation and test radiation patterns at 27 GHz, 28 GHz, 29 GHz, 30 GHz and 31 GHz. Figure 12 This is a comparison of the simulation and measured gain curves of the millimeter-wave cylindrical conformal transmission array of the double-layer Huygens metasurface of this invention. Figure 11 (a) The radiation pattern of the E-plane in the simulation and testing of the millimeter-wave cylindrical conformal transmission array of the present invention. Figure 11 Image (b) shows the radiation pattern of the H-plane of the millimeter-wave cylindrical conformal transmission array of this invention, as simulated and tested. The tested peak gain is 21.37 dBi at 30.2 GHz, and the simulated peak gain is 22.92 dBi at 28.2 GHz. The simulated 3-dB gain bandwidth ranges from 27 GHz to 29.44 GHz (8.6%). The aperture efficiency is highest at 28.2 GHz, reaching 23.2%.

[0056] This invention enables high-gain beamforming and features good conformal characteristics. Conformal metasurfaces, with their excellent shape adaptability, efficient electromagnetic wave manipulation capabilities, lightweight design, multi-functional integration, and anti-interference capabilities, have become a highly promising solution for airborne and missile-borne systems.

Claims

1. A millimeter wave cylindrical conformal transmissive array based on double-layered Huygens super-surface, characterized in that, The application relates to a 3D printing antenna, which comprises a 3D printing integral frame (1), positioning holes (2), a horn moving frame (3), a waveguide coaxial converter interface (4), a horn antenna (5), two-layer dielectric substrates (6), metal structure units (7), a foam support layer (8) and a 3D printing dielectric substrate support frame (9), the waveguide coaxial converter interface (4) is installed on the horn antenna (5) and is connected with a coaxial cable required in testing, the horn antenna (5) is embedded in the middle position of the horn moving frame (3), and the horn moving frame (3) is installed at one end of the 3D printing integral frame (1); the two-layer dielectric substrates (6) are cylindrical conformations, a plurality of metal structure units (7) are arranged on the two-layer dielectric substrates (6) along the direction of the bending of the cylinder, the foam support layer (8) is arranged between the two-layer dielectric substrates (6), the two-layer dielectric substrates (6) are fixed on the 3D printing dielectric substrate support frame (9), the 3D printing dielectric substrate support frame (9) and the 3D printing integral frame (1) are fixedly connected away from one end of the horn moving frame (3) through the pre-formed positioning holes (2), the metal structure unit (7) comprises two non-crossing I-shaped metal structures, one I-shaped metal structure of one dielectric substrate and one I-shaped metal structure of another dielectric substrate are orthogonal, and an air layer is arranged in the middle of the two-layer dielectric substrates (6).

2. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The materials of the 3D printing integral frame (1) and the 3D printing dielectric substrate support frame (9) are resin.

3. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The diameters of the positioning holes (2) are all 4.1 mm.

4. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The material of the horn moving frame (3) is resin.

5. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The waveguide coaxial converter interface (4) has a length of 7.12 mm and a width of 3.56 mm.

6. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The material of the horn antenna (5) is aluminum alloy.

7. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The two-layer dielectric substrates (6) are Taconic TLY and have a thickness of 0.508 mm.

8. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The material of the metal structure unit (7) is copper and has a thickness of 0.035 mm; the distance between the conformal transmission array center of the two-layer dielectric substrates (6) and the horn antenna (5) is 67 mm.

9. The millimeter wave cylindrical conformal transmissive array based on double-layer Huygens super-surface according to claim 1, characterized in that, The material of the foam support layer (8) is foam and has a thickness of 1.5 mm.

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