Broadband high-gain 5G base station antenna based on metasurface

Abstract

The invention relates to a broadband high-gain 5G base station antenna based on a metasurface. The broadband high-gain 5G base station antenna comprises a system floor, a first low-frequency auxiliary unit, a second low-frequency auxiliary unit, a first high-frequency auxiliary unit, a second high-frequency auxiliary unit, a center unit and a feed network, the first low-frequency auxiliary unit, the second low-frequency auxiliary unit, the first high-frequency auxiliary unit and the second high-frequency auxiliary unit are distributed on the first surface of the system floor in an array manner and surround the central unit; the central unit comprises a metasurface layer and a dual-polarization unit, the dual-polarization unit is arranged on the first surface of the system floor, and the metasurface layer is fixed on the dual-polarization unit; the feed network is arranged on the second surface of the system floor and is connected with the first low-frequency auxiliary unit, the second low-frequency auxiliary unit, the first high-frequency auxiliary unit, the second high-frequency auxiliary unit and the central unit through coaxial lines. The antenna has the advantages of wide frequency band, high average gain, high aperture efficiency and high isolation.

Description

Technical Field

[0001] The present invention belongs to the field of communication technologies, and particularly relates to a broadband high-gain 5G base station antenna based on a metasurface. Background Art

[0002] With the rapid development of 5G communication technologies, countries around the world have accelerated the construction of 5G networks. 5G technology has gradually become one of the key technologies driving the intelligent era, Internet of Things, and big data applications. The 5G network not only far exceeds the previous generation network in terms of speed, but also has broad application prospects in fields such as autonomous driving, industrial Internet, and smart cities due to its low latency and large connection capacity. To achieve the efficient operation of 5G communication, the base station antenna, as a core component of the wireless communication system, plays a crucial role.

[0003] The performance of the base station antenna directly affects the signal coverage, transmission rate, connection stability, and network capacity of the 5G network. In the 5G system, the allocation of spectrum resources is becoming increasingly tense. Therefore, the base station antenna needs to have higher bandwidth, stronger gain, and more efficient beam control capabilities to cope with higher-density device connections and more complex environmental challenges. Traditional antenna design methods, although performing well in some applications, have certain limitations in terms of gain, bandwidth, and directivity at high frequencies. Especially in the high-frequency bands of 5G network deployment, traditional antennas face a series of problems such as insufficient gain, narrow bandwidth, large size, and low power efficiency, making it difficult to meet the requirements of high-performance 5G networks.

[0004] In January 2024, Y.-F. Lin, C.-C. Chang, C.-H. Chen, J.-Y. Xie, Y.-X. Zhuang, and H.-M. Chen proposed a dual-polarized spline-loop antenna array for 5G base stations in "Dual-Polarized Spline-Loop Antenna Array With Tilt Angle Radiation for 5G Base Stations", which meets some requirements of high-performance 5G networks to a certain extent. The operating bandwidth of this antenna array is only 2.74 - 3.91 GHz (21.1%), and it cannot fully cover the entire range of the 5G-NR frequency band. When dealing with the continuously expanding spectrum resources and diverse application scenarios of future 5G networks, bandwidth limitations will occur, affecting the data transmission rate and communication capacity. In addition, the gain of this antenna array is low, and the aperture efficiency is only 30.306%, far lower than the industrial application level, which is likely to affect the overall layout and cost-effectiveness of the base station.

[0005] In recent years, as an emerging electromagnetic wave control technology, metasurface technology has gradually been applied in antenna design. A metasurface is a man-made material or structure that can precisely adjust the propagation characteristics of electromagnetic waves, with extremely high flexibility and functionality. By optimizing the geometric shape, material composition, and structural characteristics of the metasurface, functions such as beamforming, gain improvement, and bandwidth expansion can be achieved. These characteristics make the metasurface an ideal choice for enhancing the performance of 5G base station antennas.

[0006] The patent with the publication number CN119133857A discloses a dual-band co-aperture base station antenna array, which uses a composite decoupling structure to reduce high-low frequency interference, but the antenna port isolation is still not ideal, only 15 dB within the working frequency band of 3.5 - 5.0 GHz. In addition, the gain of this antenna array is low, with an average of 11.5 dBi, and the aperture efficiency is only 24.879%. This will result in a smaller coverage range and insufficient signal strength under the same radiation power. In base station construction, this may require increasing the number of antennas or raising the transmission power to make up for it, thus increasing the construction and operation costs, and in a base station environment with limited space, it will also have an adverse impact on the overall layout and resource utilization.

[0007] The patent with the publication number CN110911805A discloses a miniaturized dual-band dual-polarized 5G base station antenna with high isolation and high harmonic suppression, which realizes high isolation and harmonic suppression by using a unique resonant patch, coupling slot, and harmonic suppression stub design, but the working frequency band is narrow, only supporting a small part of the 5G-NR frequency bands, and it cannot provide comprehensive support in the face of diverse communication requirements.

[0008] The patent with the publication number CN106876982A discloses a metasurface for improving the performance of multi-antenna systems and a multi-antenna system using the metasurface, which has achieved certain results in reducing the mutual coupling between units of the multi-antenna system, improving the antenna gain and matching bandwidth through the design of the metasurface, and can be applied to various antennas and communication systems. However, this solution has deficiencies in the specific requirements of 5G base station antennas and cannot fully meet the requirements for efficient signal transmission in specific frequency bands of 5G base stations; moreover, this metasurface design does not focus on the miniaturization requirement, and it will be restricted in practical applications for the deployment scenario of 5G base stations with limited space.

[0009] In summary, the existing antennas have defects such as narrow working frequency bands, low antenna gain, low aperture efficiency, and low isolation. Summary of the Invention

[0010] To solve the above problems existing in the prior art, the present invention provides a broadband high-gain 5G base station antenna based on a metasurface. The technical problems to be solved by the present invention are achieved through the following technical solutions: An embodiment of the present invention provides a broadband high-gain 5G base station antenna based on a metasurface, including: a system floor, a first low-frequency auxiliary unit, a second low-frequency auxiliary unit, a first high-frequency auxiliary unit, a second high-frequency auxiliary unit, a central unit, and a feeding network, where, The first low-frequency auxiliary unit, the second low-frequency auxiliary unit, the first high-frequency auxiliary unit, and the second high-frequency auxiliary unit are arranged in an array on a first surface of the system floor and surround the central unit. The first low-frequency auxiliary unit and the second low-frequency auxiliary unit are diagonally distributed, and the first high-frequency auxiliary unit and the second high-frequency auxiliary unit are diagonally distributed; The central unit includes a metasurface layer and a dual-polarization unit. The dual-polarization unit is arranged on the first surface of the system floor and the metasurface layer is fixed on the dual-polarization unit; The feeding network is arranged on a second surface of the system floor and is respectively connected to the first low-frequency auxiliary unit, the second low-frequency auxiliary unit, the first high-frequency auxiliary unit, the second high-frequency auxiliary unit, and the central unit through coaxial cables.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: By arranging a metasurface layer in the central unit, the antenna of the present invention realizes a wide operating frequency band through the metasurface structure, can integrate and utilize 5G-NR frequency band resources, ensure seamless network connection, and improve communication reliability and universality; by virtue of the electromagnetic characteristics of the metasurface, high antenna gain and high aperture efficiency are achieved, the signal can be focused and enhanced, the signal can propagate farther and stronger under the same transmission power, and at the same time, high aperture efficiency can be obtained with a small area, reducing energy waste and scattering; the cross-dipole array design with the low-frequency auxiliary units diagonally distributed and the high-frequency auxiliary units diagonally distributed ensures high isolation, enables the signals to be independent when multiple antennas work, avoids interference, and improves system capacity and reliability. Description of the Drawings

[0012] Figure 1 It is a three-dimensional structural schematic diagram of the broadband high-gain 5G base station antenna based on a metasurface provided by an embodiment of the present invention; Figure 2 It is a three-dimensional structural schematic diagram of the central unit provided by an embodiment of the present invention; Figure 3 It is a planar structural schematic diagram of the metasurface layer in the central unit provided by an embodiment of the present invention; Figures 4a - 4c It is a schematic diagram of a cross-shaped patch in the metasurface layer provided by an embodiment of the present invention; Figure 5 It is a three-dimensional structural schematic diagram of the dual-polarization unit in the central unit provided by an embodiment of the present invention; Figure 6Schematic diagram of the planar structure of the first reflection layer in the dual-polarization unit provided by the embodiment of the present invention; Figure 7 Schematic diagram of the structure of the first feed balun in the dual-polarization unit provided by the embodiment of the present invention; Figure 8 Schematic diagram of the three-dimensional structure of the low-frequency auxiliary unit provided by the embodiment of the present invention; Figure 9 Schematic diagram of the planar structure of the second reflection layer in the low-frequency auxiliary unit provided by the embodiment of the present invention; Figure 10 Schematic diagram of the structure of the second feed balun in the low-frequency auxiliary unit provided by the embodiment of the present invention; Figure 11 Schematic diagram of the three-dimensional structure of the high-frequency auxiliary unit provided by the embodiment of the present invention; Figure 12 Schematic diagram of the planar structure of the third reflection layer in the high-frequency auxiliary unit provided by the embodiment of the present invention; Figure 13 Schematic diagram of the structure of the third feed balun in the high-frequency auxiliary unit provided by the embodiment of the present invention; Figure 14 Schematic diagram of the planar view of the feed network provided by the embodiment of the present invention; Figure 15 Schematic diagram of the side structure of the broadband high-gain 5G base station antenna based on the metasurface provided by the embodiment of the present invention; Figure 16 Antenna reflection coefficient curve of the present invention; Figure 17 Antenna port isolation curve of the present invention; Figure 18 Antenna gain curve of the present invention; Figure 19 Radiation pattern of the antenna of the present invention at the frequency point of 3.6 GHz and Phi = 90; Figure 20 Radiation pattern of the antenna of the present invention at the frequency point of 3.6 GHz and Phi = 0; Figure 21 Radiation pattern of the antenna of the present invention at the frequency point of 4.8 GHz and Phi = 90; Figure 22 Radiation pattern of the antenna of the present invention at the frequency point of 4.8 GHz and Phi = 0. Detailed implementation manners

[0013] The present invention will be further described in detail below with reference to specific embodiments, but the implementation manners of the present invention are not limited thereto.

[0014] Embodiment 1 Please refer to Figure 1 ,Figure 1 Schematic diagram of the three-dimensional structure of the broadband high-gain 5G base station antenna based on metasurface provided by the embodiment of the present invention.

[0015] The broadband high-gain 5G base station antenna based on metasurface in this embodiment includes a system floor 1, a first low-frequency auxiliary unit 2, a second low-frequency auxiliary unit 3, a first high-frequency auxiliary unit 4, a second high-frequency auxiliary unit 5, a central unit 6, and a feeding network 7.

[0016] Among them, the first low-frequency auxiliary unit 2, the second low-frequency auxiliary unit 3, the first high-frequency auxiliary unit 4, and the second high-frequency auxiliary unit 5 are arranged in an array on the first surface of the system floor 1 and surround the central unit 6. The first low-frequency auxiliary unit 2 and the second low-frequency auxiliary unit 3 are diagonally distributed, and the first high-frequency auxiliary unit 4 and the second high-frequency auxiliary unit 5 are diagonally distributed; the central unit 6 includes a metasurface layer 61 and a dual-polarization unit. The dual-polarization unit is arranged on the first surface of the system floor 1, and the metasurface layer 61 is fixed on the dual-polarization unit; the feeding network 7 is arranged on the second surface of the system floor 1 and is respectively connected to the microstrip feed lines of the first low-frequency auxiliary unit 2, the second low-frequency auxiliary unit 3, the first high-frequency auxiliary unit 4, the second high-frequency auxiliary unit 5, and the central unit 6 through coaxial cables.

[0017] Specifically, the first low-frequency auxiliary unit 2, the second low-frequency auxiliary unit 3, the first high-frequency auxiliary unit 4, and the second high-frequency auxiliary unit 5 are all fixed on the first surface of the system floor 1 through inserts to form a 2×2 array. The first low-frequency auxiliary unit 2 and the second low-frequency auxiliary unit 3 are located on one diagonal of the array, the first high-frequency auxiliary unit 4 and the second high-frequency auxiliary unit 5 are located on the other diagonal of the array, and the central unit 6 is located at the central position of the array. The feeding network 7 is printed on a dielectric substrate, and the dielectric substrate is fixed on the second surface of the system floor 1, and the printed feeding network 7 is far from the second surface of the system floor 1. The first low-frequency auxiliary unit 2, the second low-frequency auxiliary unit 3, the first high-frequency auxiliary unit 4, and the second high-frequency auxiliary unit 5 are respectively connected to the feeding network 7 through coaxial cables penetrating the system floor.

[0018] In the embodiment of the present invention, the first surface and the second surface are two opposite surfaces.

[0019] Specifically, the frequency bands of the first low-frequency auxiliary unit 2 and the second low-frequency auxiliary unit 3 are 3-4 GHz, and the frequency bands of the first high-frequency auxiliary unit 4 and the second high-frequency auxiliary unit 5 are 4-5 GHz. After forming an array, the frequency bands of all units are optimized to 3.3-5 GHz, and the wavelength range corresponding to 3.3-5 GHz is 60-90.9 mm.

[0020] Specifically, among the first low-frequency auxiliary unit 2, the second low-frequency auxiliary unit 3, the first high-frequency auxiliary unit 4, and the second high-frequency auxiliary unit 5, the distance between the centers of two adjacent auxiliary units is 0.6 times the wavelength, and the distance from the center of each auxiliary unit to the center of the central unit 6 is 0.75 times the wavelength.

[0021] In this embodiment, the distance between the centers of two adjacent auxiliary units is 0.6 times the wavelength, which can effectively avoid the occurrence of grating lobes, ensure that the signal is mainly concentrated in the main lobe direction, and improve the directivity of the signal and the concentration degree of energy. The distance from the center of each auxiliary antenna to the center of the central unit 6 is 0.75 times the wavelength, which is used to adjust the electromagnetic coupling strength between the antenna unit and the central part, so that the mutual coupling between the low-frequency auxiliary antenna and the high-frequency auxiliary antenna is within a suitable range, avoid signal interference caused by too strong coupling, and at the same time use a certain coupling effect to optimize the performance of the entire antenna, realizing an increase in bandwidth and improvement in signal stability.

[0022] Through the combination of auxiliary antennas in different frequency bands, the positioning of the central unit, and the optimization of the unit spacing, this embodiment can effectively increase the bandwidth and reduce the coupling interference between antenna units.

[0023] Please refer to Figure 2 , Figure 2 which is a three-dimensional structural schematic diagram of the central unit provided by the embodiment of the present invention. The central unit 6 includes a metasurface layer 61 and a dual-polarization unit. The dual-polarization unit is disposed on the first surface of the system floor 1, and the metasurface layer 61 is fixed on the dual-polarization unit.

[0024] Specifically, the metasurface layer 61 is fixed directly above the dual-polarization unit by four long nylon studs 64, and the dual-polarization unit is fixed in the exact middle of the system floor 1 by inserts.

[0025] Please refer to Figure 3 , Figure 3 which is a planar structural schematic diagram of the metasurface layer in the central unit provided by the embodiment of the present invention. The metasurface layer 61 includes a first dielectric substrate 611 and a plurality of cross-shaped patches 612. Among them, the plurality of cross-shaped patches 612 are distributed in a cross array on the surface of the first dielectric substrate 611 away from the system floor 1. Exemplarily, the metasurface layer 61 is formed by a cross array of the first dielectric substrate 611 and 3×5 cross-shaped patches 612.

[0026] Please refer to Figures 4a - 4c , Figures 4a - 4c which is a schematic diagram of the cross-shaped patch in the metasurface layer provided by the embodiment of the present invention. Among them, Figure 4a is the structural schematic diagram of the cross-shaped patch, Figure 4b is the equivalent circuit schematic diagram of the cross-shaped patch, Figure 4c isFigure 4b The circuit diagram represented by the square box.

[0027] Please refer to Figure 4a , each cross-shaped patch 612 is formed by a solid cross-shaped patch 6121 and four hollow symmetric M-shaped patches 6122 connected to the four branch ends of the solid cross-shaped patch 6121. Each hollow symmetric M-shaped patch 6122 has two mirror-symmetric M-shaped units, and each M-shaped unit is formed by multiple bends of a microstrip line with a bending angle of 90°.

[0028] Please refer to Figure 4b and Figure 4c , in the solid cross-shaped patch 6121, each branch is equivalent to an inductor, and the four branches can be equivalent to four inductors (L1, L2, L3, L4). In each M-shaped unit, the sub-microstrip line ML extending along the branch of the solid cross-shaped patch 6121 is equivalent to an inductor, and the blank part between the two sub-microstrip lines ML is equivalent to a capacitor, as shown in Figure 4c shown. Figure 4c is Figure 4b the equivalent circuit between C1 and L4 in

[0029] Please refer to Figure 5 , Figure 5 This is the schematic diagram of the three-dimensional structure of the dual-polarization unit in the central unit provided by the embodiment of the present invention. The dual-polarization unit includes a first reflection layer 62 and a first feeding balun 63. Among them, the metasurface layer 61 is fixed on one side of the first reflection layer 62 through a plurality of long nylon studs 64; the first feeding balun 63 is arranged on the other side of the first reflection layer 62 and is fixed on the system floor 1 through inserts; the first feeding balun 63 is connected to the feeding network 7 through a coaxial cable passing through the system floor 1.

[0030] Please refer to Figure 6 , Figure 6Schematic diagram of the planar structure of the first reflection layer in the dual-polarization unit provided by the embodiment of the present invention. The first reflection layer 62 includes a second dielectric substrate 621 and four spindle-shaped patches 622. Among them, the four spindle-shaped patches 622 are symmetrically arranged on the surface of the second dielectric substrate 621 far from the system floor 1; each spindle-shaped patch 622 includes a first straight segment 6221 and two first smooth curve segments 6222. The two first smooth curve segments 6222 extend from the two ends of the first straight segment 6221 until they intersect to form a closed axisymmetric figure; the first straight segments 6221 of the four spindle-shaped patches 622 are close to each other and are pairwise opposite. It can be understood that in each spindle-shaped patch, the two ends of the first straight segment 6221 are respectively connected to the ends of the two first smooth curve segments 6222, and the other ends of the two first smooth curve segments 6222 intersect, and the intersection part is far from the center of the second dielectric substrate 621.

[0031] Exemplarily, Figure 6 In, the second dielectric substrate 621 is square, the width W1 is 35 mm, the length W2 of the first straight segment 6221 is 3.25 mm, and the dimension W3 in the first smooth curve segment 6222 is 12.48 mm.

[0032] In this embodiment, four spindle-shaped patches are arranged on the second dielectric substrate to form the first reflection layer. The four spindle-shaped patches are the main electromagnetic radiation and reflection structures of the first reflection layer. The spindle shape and the central symmetric layout can affect the amplitude and phase of the reflected signal, and reflect the signals in different polarization directions in a targeted manner, so as to achieve optimized reflection of the dual-polarization signal and improve the performance of the dual-polarization unit.

[0033] Please refer to Figure 7 , Figure 7 Schematic diagram of the structure of the first feeding balun in the dual-polarization unit provided by the embodiment of the present invention. The first feeding balun 63 includes a first central feeding component 631 and a second central feeding component 632 that are vertically crossed in space.

[0034] The first central feeding component 631 includes a third dielectric substrate 6311, a first microstrip feeding line 6312, a first parasitic patch 6313, and a second parasitic patch 6314; the third dielectric substrate 6311 is fixed on the system floor 1 by inserts, the first microstrip feeding line 6312 is arranged on the first surface of the third dielectric substrate 6311 and is connected to the feeding network 7 through a coaxial cable, and the first parasitic patch 6313 and the second parasitic patch 6314 are symmetrically distributed on the second surface of the third dielectric substrate 6311.

[0035] The second center feeding component 632 includes a fourth dielectric substrate 6321, a second microstrip feeder 6322, a third parasitic patch 6323, and a fourth parasitic patch 6324; the fourth dielectric substrate 6321 is fixed on the system floor 1 through inserts, the second microstrip feeder 6322 is arranged on the first surface of the fourth dielectric substrate 6321 and is connected to the feeding network 7 through a coaxial cable, and the third parasitic patch 6323 and the fourth parasitic patch 6324 are symmetrically distributed on the second surface of the fourth dielectric substrate 6321. The first microstrip feeder 6312 and the second microstrip feeder 6322 form an electromagnetic coupling structure in the crossing area, constituting the feeding network of the dual-polarization unit.

[0036] Specifically, two protrusions are provided at the tops of the third dielectric substrate 6311 and the fourth dielectric substrate 6321 for inserting into the first reflective layer 62 to fix the first feeding balun 63. A slit is provided at the bottom of the third dielectric substrate 6311, and a slit is provided at the top of the fourth dielectric substrate 6321. The two dielectric substrates are respectively inserted into the corresponding slits to make the planes where the two dielectric substrates are located perpendicular to each other.

[0037] Specifically, the first microstrip feeder 6312 is formed by connecting three microstrip lines a1, b1, and c1 with gradually increasing widths, and the microstrip lines a1 and b1 have transverse bending segments, and the microstrip line c1 is used to connect the coaxial cable. The second microstrip feeder 6322 is formed by connecting three microstrip lines a2, b2, and c2 with gradually increasing widths, and the microstrip lines a2 and b2 have transverse bending segments, and the microstrip line c2 is used to connect the coaxial cable. The height of the second microstrip feeder 6322 is less than the height of the first microstrip feeder 6312, so that the second microstrip feeder 6322 does not contact the first microstrip feeder 6312 and forms an electromagnetic coupling structure in the crossing area, jointly constituting the feeding network of the dual-polarization unit.

[0038] Please refer to Figure 8 , Figure 8 which is a schematic three-dimensional structure diagram of the low-frequency auxiliary unit provided by the embodiment of the present invention. The structures of the first low-frequency auxiliary unit 2 and the second low-frequency auxiliary unit 3 are the same, and both include a second reflective layer 21 and a second feeding balun 22 fixed between the second reflective layer 21 and the system floor 1. Specifically, the second feeding balun 22 is fixed on the system floor 1 through inserts, and the second reflective layer 21 is fixed on the second feeding balun 22.

[0039] Please refer to Figure 9 , Figure 9Schematic diagram of the planar structure of the second reflection layer in the low-frequency auxiliary unit provided by the embodiment of the present invention. The second reflection layer 21 includes a fifth dielectric substrate 211, a hollow diamond patch 212, and four nested willow-leaf patches 213; the hollow diamond patch 212 and the four nested willow-leaf patches 213 are arranged on the surface of the fifth dielectric substrate 211 away from the system floor 1; the four nested willow-leaf patches 213 are centrosymmetrically arranged and located inside the hollow diamond patch 212; each nested willow-leaf patch 213 includes a nested inner ring 2131 and an outer ring 2132, and the inner ring 2131 and the outer ring 2132 have the same shape.

[0040] Specifically, the hollow diamond patch 212 is located at the center of the entire structure. The outer ring of the nested willow-leaf patch 213 is located inside the hollow diamond patch 212 and adjacent to the hollow diamond patch 212; the inner ring 2131 is located inside the outer ring 2132 and is spaced apart from the outer ring 2132 by a certain distance. From the overall layout, with the hollow diamond patch 212 as the center, the outer ring 2132 of the nested willow-leaf patch 213 and the inner ring 2131 of the nested willow-leaf patch 213 are arranged inward in sequence.

[0041] Furthermore, the outer ring 2132 includes a second straight-line segment 21321 and two second smooth curve segments 21322. The two second smooth curve segments 21322 extend from the two ends of the second straight-line segment 21321 until they intersect at the inner angle of the hollow diamond patch 212 to form a closed axisymmetric figure. The second straight-line segments 21321 of the four outer rings 2132 are close to each other and pairwise opposite. The inner ring 2131 includes a third straight-line segment 21311 and two third smooth curve segments 21312. The two third smooth curve segments 21312 extend from the two ends of the third straight-line segment 21311 until they intersect to form a closed axisymmetric figure; the third straight-line segments 21311 of the four inner rings 2131 are parallel to the second straight-line segments 21321 of the corresponding outer rings.

[0042] Exemplarily, the fifth dielectric substrate 211 is square, its width W4 is 35 mm, the length W5 of the second straight-line segment 21321 of the outer ring 2132 in the nested willow-leaf patch 213 is 3.25 mm, the size W6 of the second smooth curve segment 21322 is 13.51 mm, and the width W7 of the hollow diamond patch 212 is 23 mm.

[0043] The second reflection layer of this embodiment includes a hollow diamond patch and four nested willow-leaf patches. The hollow diamond patch and the nested willow-leaf patches can enhance the radiation efficiency of the antenna and adjust the reflection characteristics of electromagnetic waves.

[0044] Please refer to Figure 10 , Figure 10Schematic diagram of the structure of the second feeding balun in the low-frequency auxiliary unit provided by the embodiment of the present invention. The second feeding balun 22 includes a first low-frequency feeding component 221 and a second low-frequency feeding component 222 that are vertically crossed in space. The first low-frequency feeding component 221 includes a sixth dielectric substrate 2211, a third microstrip feeder 2212, a fifth parasitic patch 2213, and a sixth parasitic patch 2214; the sixth dielectric substrate 2211 is fixed on the system floor 1 through inserts, the third microstrip feeder 2212 is arranged on the first surface of the sixth dielectric substrate 2211 and is connected to the feeding network 7 through a coaxial cable, and the fifth parasitic patch 2213 and the sixth parasitic patch 2214 are symmetrically distributed on the second surface of the sixth dielectric substrate 2211. The second low-frequency feeding component 222 includes a seventh dielectric substrate 2221, a fourth microstrip feeder 2222, a seventh parasitic patch 2223, and an eighth parasitic patch 2224; the seventh dielectric substrate 2221 is fixed on the system floor 1 through inserts, the fourth microstrip feeder 2222 is arranged on the first surface of the seventh dielectric substrate 2221 and is connected to the feeding network 7 through a coaxial cable, and the seventh parasitic patch 2223 and the eighth parasitic patch 2224 are symmetrically distributed on the second surface of the seventh dielectric substrate 2221. The third microstrip feeder 2212 and the fourth microstrip feeder 2222 form an electromagnetic coupling structure in the crossing area, jointly constituting the radiation network of the low-frequency auxiliary unit.

[0045] Specifically, two protrusions are provided on the tops of the sixth dielectric substrate 2211 and the seventh dielectric substrate 2221 for inserting into the second reflective layer 21 to fix the second feeding balun 22. A gap is provided at the bottom of the sixth dielectric substrate 2211, and a gap is provided at the top of the seventh dielectric substrate 2221. The two dielectric substrates are respectively inserted into the corresponding gaps to make the planes where the two dielectric substrates are located perpendicular to each other.

[0046] Specifically, the third microstrip feeder 2212 is formed by connecting three microstrip lines a3, b3, and c3 with gradually increasing widths, and the microstrip lines a3 and b3 have lateral bending segments, and the microstrip line c3 is used to connect the coaxial cable. The fourth microstrip feeder 2222 is formed by connecting three microstrip lines a4, b4, and c4 with gradually increasing widths, and the microstrip lines a4 and b4 have lateral bending segments, and the microstrip line c4 is used to connect the coaxial cable. The height of the fourth microstrip feeder 2222 is less than the height of the third microstrip feeder 2212, so that the fourth microstrip feeder 2222 and the third microstrip feeder 2212 do not contact each other and form an electromagnetic coupling structure in the crossing area, jointly constituting the radiation network.

[0047] In this embodiment, the fifth parasitic patch, the sixth parasitic patch, the seventh parasitic patch, and the eighth parasitic patch interact with the main radiation structure (the hollow diamond patch and the nested willow leaf patch), which can improve impedance matching, increase the bandwidth, and adjust the radiation direction. The third microstrip feeder and the fourth microstrip feeder effectively transmit the external radio frequency energy into the radiation structure (the hollow diamond patch and the nested willow leaf patch) of the antenna element, ensuring that the energy can accurately excite the antenna element to generate the required electromagnetic radiation. At the same time, to a certain extent, they participate in the adjustment of impedance matching, reduce energy reflection, and improve energy transmission efficiency.

[0048] Please refer to Figure 11 , Figure 11 which is a schematic three-dimensional structure diagram of the high-frequency auxiliary unit provided by an embodiment of the present invention. The structures of the first high-frequency auxiliary unit 4 and the second high-frequency auxiliary unit 5 are the same, and both include a third reflection layer 41 and a third feeding balun 42 fixedly arranged between the third reflection layer 41 and the system floor 1. Specifically, the third feeding balun 42 is fixed on the system floor 1 through a plug, and the third reflection layer 41 is fixed on the third feeding balun 42.

[0049] Please refer to Figure 12 , Figure 12 which is a schematic plan view of the third reflection layer in the high-frequency auxiliary unit provided by an embodiment of the present invention. The third reflection layer 41 includes an eighth dielectric substrate 411 and four windmill blade-shaped patches 412. The four windmill blade-shaped patches 412 are symmetrically arranged at the center on the surface of the eighth dielectric substrate 411.

[0050] Exemplarily, the four windmill blade-shaped patches 412 are arranged in pairs opposite to each other on the same straight line and are located on the diagonal line of the eighth dielectric substrate 411. The included angle between the center lines of two adjacent windmill blade-shaped patches 412 is 90°. 45° chamfers are provided at the ends where the four windmill blade-shaped patches 412 are close to each other. The shape of the eighth dielectric substrate 411 is square, and the width W8 is 34 mm. The length W9 of each windmill blade-shaped patch 412 is 17 mm, and the width W10 is 4.2 mm.

[0051] In this embodiment, the four windmill blade-shaped patches interact with the surrounding electromagnetic fields, determine the radiation characteristics of the antenna element, and realize the effective radiation and reception of high-frequency signals.

[0052] Please refer to Figure 13 , Figure 13It is a schematic structural diagram of the third feeding balun in the high-frequency auxiliary unit provided by the embodiment of the present invention. The third feeding balun 42 includes a first high-frequency feeding component 421 and a second high-frequency feeding component 422 that are vertically crossed in space. The first high-frequency feeding component 421 includes a ninth dielectric substrate 4211, a fifth microstrip feeding line 4212, a ninth parasitic patch 4213, and a tenth parasitic patch 4214; the ninth dielectric substrate 4211 is fixed on the system floor 1 through an insert, the fifth microstrip feeding line 4212 is arranged on the first surface of the ninth dielectric substrate 4211 and is connected to the feeding network 7 through a coaxial cable, and the ninth parasitic patch 4213 and the tenth parasitic patch 4214 are symmetrically distributed on the second surface of the ninth dielectric substrate 4211. The second high-frequency feeding component 422 includes a tenth dielectric substrate 4221, a sixth microstrip feeding line 4222, an eleventh parasitic patch 4223, and a twelfth parasitic patch 4224; the tenth dielectric substrate 4221 is fixed on the system floor 1 through an insert, the sixth microstrip feeding line 4222 is arranged on the first surface of the tenth dielectric substrate 4221 and is connected to the feeding network 7 through a coaxial cable, and the eleventh parasitic patch 4223 and the twelfth parasitic patch 4224 are symmetrically distributed on the second surface of the tenth dielectric substrate 4221. The fifth microstrip feeding line 4212 and the sixth microstrip feeding line 4222 form an electromagnetic coupling structure in the crossing area, constituting the feeding network of the high-frequency auxiliary unit.

[0053] Specifically, a gap is provided at the bottom of the ninth dielectric substrate 4211, and a gap is provided at the top of the tenth dielectric substrate 4221. The two dielectric substrates are respectively inserted into the corresponding gaps, so that the planes where the two dielectric substrates are located are orthogonal to each other, forming a vertically crossed structure. Thus, the two dielectric substrates and the microstrip feeding lines and parasitic patches thereon constitute a spatially orthogonal radiation and feeding network, thereby realizing the functions of directional transmission and impedance matching of high-frequency signals.

[0054] Specifically, the fifth microstrip feeding line 4212 is formed by connecting three microstrip lines a5, b5, and c5, and the microstrip line a5 has a lateral bending section, and the microstrip line c5 is used to connect the coaxial cable. The sixth microstrip feeding line 4222 is formed by connecting three microstrip lines a6, b6, and c6, and the microstrip line a6 has a lateral bending section, and the microstrip line c6 is used to connect the coaxial cable. The lateral bending sections of the fifth microstrip feeding line 4212 and the sixth microstrip feeding line 4222 are staggered, so that the fifth microstrip feeding line 4212 and the sixth microstrip feeding line 4222 do not contact each other and form an electromagnetic coupling structure in the crossing area, jointly constituting the feeding network.

[0055] Specifically, the ninth parasitic patch 4213 and the tenth parasitic patch 4214 form opposite L shapes, and both have protrusions formed at the top; the eleventh parasitic patch 4223 and the twelfth parasitic patch 4224 form opposite L shapes, and both have protrusions formed at the top. The four protrusions are inserted into the third reflective layer 41 to fix the third feed balun 42.

[0056] The ninth parasitic patch, the tenth parasitic patch, the eleventh parasitic patch, and the twelfth parasitic patch in this embodiment can serve as auxiliary radiators, mutually couple with the main radiation unit (windmill blade-shaped patch), change the current distribution of the antenna unit, increase the operating bandwidth, and improve the matching performance.

[0057] Please refer to Figure 14 , Figure 14 which is a schematic plan view of the feed network provided by the embodiment of the present invention. The feed network 7 includes a first sub-network 71 and a second sub-network 72. Among them, the first sub-network 71 is used to connect the microstrip feed line with the first polarization angle, and includes a first Wilkinson power divider WPD1, a second Wilkinson power divider WPD2, a first T-shaped power divider T1, and a second T-shaped power divider T2; the input end of the first Wilkinson power divider WPD1 serves as the first external port P1 of the feed network 7, the first output end is connected to the input end of the second Wilkinson power divider WPD2, and the second output end is connected to the input end of the first T-shaped power divider T1; the first output end of the first T-shaped power divider T1 serves as the first output port H1 of the feed network 7, and the second output end is connected to the input end of the second T-shaped power divider T2; the first output end and the second output end of the second T-shaped power divider T2 serve as the second output port H2 and the third output port H3 of the feed network 7 respectively; the first output end and the second output end of the second Wilkinson power divider WPD2 serve as the fourth output port H4 and the fifth output port H5 of the feed network 7 respectively.

[0058] The second sub-network 72 is used to connect the microstrip feed line with the second polarization angle, and includes a third Wilkinson power divider WPD3, a fourth Wilkinson power divider WPD4, a third T-shaped power divider T3, and a fourth T-shaped power divider T4; the input end of the third Wilkinson power divider WPD3 serves as the second external port P2 of the feed network 7, the first output end is connected to the input end of the fourth Wilkinson power divider WPD4, and the second output end is connected to the input end of the third T-shaped power divider T3; the first output end of the third T-shaped power divider T3 serves as the sixth output port H6 of the feed network 7, and the second output end is connected to the input end of the fourth T-shaped power divider T4; the first output end and the second output end of the fourth T-shaped power divider T4 serve as the seventh output port H7 and the eighth output port H8 of the feed network 7 respectively; the first output end and the second output end of the fourth Wilkinson power divider WPD4 serve as the ninth output port H9 and the tenth output port H10 of the feed network 7 respectively.

[0059] The central unit 6 is connected to the first output port H1 and the sixth output port H6 respectively through two coaxial cables; the first low-frequency auxiliary unit 2 is connected to the second output port H2 and the seventh output port H7 respectively through two coaxial cables; the second low-frequency auxiliary unit 3 is connected to the third output port H3 and the eighth output port H8 respectively through two coaxial cables; the first high-frequency auxiliary unit 4 is connected to the fourth output port H4 and the ninth output port H9 respectively through two coaxial cables; the second high-frequency auxiliary unit 5 is connected to the fifth output port H5 and the tenth output port H10 respectively through two coaxial cables.

[0060] Please refer to Figure 15 , Figure 15 which is a schematic side view of the broadband high-gain 5G base station antenna based on metasurface provided by the embodiment of the present invention. The central unit 6 has coaxial cables 11a, 11b, the first low-frequency auxiliary unit 2 has coaxial cables 11c, 11d, the second low-frequency auxiliary unit 3 has coaxial cables 11e, 11f, the first high-frequency auxiliary unit 4 has coaxial cables 11g, 11h, and the second high-frequency auxiliary unit 5 has coaxial cables 11i, 11j. Each coaxial cable has an inner conductor, an isolation layer, and an outer conductor. All coaxial cables pass through the system floor 1, and the outer conductors of all coaxial cables are connected to the system floor 1, and the inner conductors are connected to the output ports of the feeding network 7.

[0061] It should be noted that the first output port H1, the second output port H2, the third output port H3, the fourth output port H4, and the fifth output port H5 of the first sub-network 71 are connected to microstrip feed lines with a first polarization angle, and the sixth output port H6, the seventh output port H7, the eighth output port H8, the ninth output port H9, and the tenth output port H10 of the second sub-network 72 are connected to microstrip feed lines with a second polarization angle. Exemplarily, the microstrip feed lines in the first low-frequency auxiliary unit 2, the second low-frequency auxiliary unit 3, the first high-frequency auxiliary unit 4, the second high-frequency auxiliary unit 5, and the central unit 6 are all dual-polarization microstrip feed lines, one with a polarization angle of +45° and the other with a polarization angle of -45°. Then, the output ports of the first sub-network 71 are all connected to microstrip feed lines with a polarization angle of +45°, and the output ports of the second sub-network 72 are all connected to microstrip feed lines with a polarization angle of -45°, or the output ports of the first sub-network 71 are all connected to microstrip feed lines with a polarization angle of -45°, and the output ports of the second sub-network 72 are all connected to microstrip feed lines with a polarization angle of +45°.

[0062] Specifically, in the central unit 6, the polarization angle of the first microstrip feeder line 6312 of the first feeding balun 63 is +45°, and the polarization angle of the second microstrip feeder line 6322 is -45°. Then, the inner conductor of the coaxial cable 11a is connected to the bottom of the first microstrip feeder line 6312, and passes through the system floor 1 to be connected to the first output port H1 of the feeding network 7; the inner conductor of the coaxial cable 11b is connected to the bottom of the second microstrip feeder line 6322, and passes through the system floor 1 to be connected to the sixth output port H6 of the feeding network 7.

[0063] In the first low-frequency auxiliary unit 2, the polarization angle of the third microstrip feeder line 2212 of the second feeding balun 22 is +45°, and the polarization angle of the fourth microstrip feeder line 2222 is -45°. Then, the inner conductor of the coaxial cable 11c is connected to the bottom of the third microstrip feeder line 2212, and passes through the system floor 1 to be connected to the second output port H2 of the feeding network 7; the inner conductor of the coaxial cable 11d is connected to the bottom of the fourth microstrip feeder line 2222, and passes through the system floor 1 to be connected to the seventh output port H7 of the feeding network 7.

[0064] In the second low-frequency auxiliary unit 3, the inner conductor of the coaxial cable 11e is connected to the bottom of the microstrip feeder line with a polarization angle of +45° in the second low-frequency auxiliary unit 3, and passes through the system floor 1 to be connected to the third output port H3 of the feeding network 7; the inner conductor of the coaxial cable 11f is connected to the bottom of the microstrip feeder line with a polarization angle of -45° in the second low-frequency auxiliary unit 3, and passes through the system floor 1 to be connected to the eighth output port H8 of the feeding network 7.

[0065] In the first high-frequency auxiliary unit 4, the polarization angle of the fifth microstrip feeder line 4212 of the third feeding balun 42 is +45°, and the polarization angle of the sixth microstrip feeder line 4222 is -45°. Then, the inner conductor of the coaxial cable 11g is connected to the bottom of the fifth microstrip feeder line 4212, and passes through the system floor 1 to be connected to the fourth output port H4 of the feeding network 7; the inner conductor of the coaxial cable 11h is connected to the bottom of the sixth microstrip feeder line 4222, and passes through the system floor 1 to be connected to the ninth output port H9 of the feeding network 7.

[0066] In the second high-frequency auxiliary unit 5, the inner conductor of the coaxial cable 11i is connected to the bottom of the microstrip feeder line with a polarization angle of +45° in the second high-frequency auxiliary unit 5, and passes through the system floor 1 to be connected to the fifth output port H5 of the feeding network 7; the inner conductor of the coaxial cable 11j is connected to the bottom of the microstrip feeder line with a polarization angle of -45° in the second high-frequency auxiliary unit 5, and passes through the system floor 1 to be connected to the tenth output port H10 of the feeding network 7.

[0067] In the antenna array of the present invention, P1 and P2 are the external ports of the antenna array, which can be external input ports or external output ports.

[0068] In this embodiment, the system floor 1 is made of metallic aluminum material; the first dielectric substrate 611, the second dielectric substrate 621, the third dielectric substrate 6311, the fourth dielectric substrate 6321, the fifth dielectric substrate 211, the sixth dielectric substrate 2211, the seventh dielectric substrate 2221, the eighth dielectric substrate 411, the ninth dielectric substrate 4211, and the tenth dielectric substrate 4221 are all made of FR-4 material. The relative dielectric constant of the FR-4 material is 4.3, the dielectric loss is 0.016, and the board thickness is 0.8 mm for all of them. The characteristic impedance of the coaxial cable is 50 ohms for all.

[0069] The effects of the broadband high-gain 5G base station antenna based on the metasurface in this embodiment will be described below in combination with the simulation results.

[0070] Please refer to Figure 16 , Figure 16 which is the antenna reflection coefficient curve diagram of the present invention. Among them, |S 11 | is the reflection coefficient of the antenna port P1, and the operating frequency band of the port P1 is 3.3 GHz - 5.0 GHz; |S 22 | is the reflection coefficient of the antenna port P2, and the operating frequency band of the port P2 is 3.3 GHz - 5.0 GHz.

[0071] Figure 16 In terms of the operating bandwidth, the relative bandwidth of the antenna of the present invention is 40.96%.

[0072] The relative bandwidth of the antenna proposed in the article "Dual - Polarized Spline - Loop Antenna Array With Tilt Angle Radiation for 5G Base Stations" by Y.-F. Lin, C.-C. Chang, C.-H. Chen, J.-Y. Xie, Y.-X. Zhuang, and H.-M. Chen is 35.19%. In comparison, the percentage increase in the relative bandwidth of the antenna of the present invention is 16.39%.

[0073] The relative bandwidth of the antenna proposed in the comparative solution CN119133857A is 21.1%. In comparison, the relative bandwidth of the antenna of the present invention is increased by 89.57% and can cover the N77 (3.3 GHz - 4.2 GHz), N78 (3.3 GHz - 3.8 GHz), and N79 (4.4 GHz - 5.0 GHz) frequency bands of 5G-NR.

[0074] The operating bandwidth of the antenna proposed in Comparative Solution CN106876982A is 8.9%. In contrast, the operating bandwidth of the antenna of the present invention is increased by 360.22% and can cover the N77 (3.3 GHz - 4.2 GHz), N78 (3.3 GHz - 3.8 GHz), and N79 (4.4 GHz - 5.0 GHz) frequency bands of 5G-NR.

[0075] Please refer to Figure 17 , Figure 17 which is the antenna port isolation degree curve of the present invention. Among them, |S 21 | is the forward transmission coefficient of antenna port P1 to port P2. Obviously, in the operating frequency band of 3.3 GHz - 5.0 GHz, the isolation degree between port P1 and port P2 is less than -20.78 dB.

[0076] The isolation degree of the antenna proposed in the article "Dual - Polarized Spline - Loop Antenna Array With Tilt Angle Radiation for 5G Base Stations" by Y.-F. Lin, C.-C. Chang, C.-H. Chen, J.-Y. Xie, Y.-X. Zhuang, and H.-M. Chen is 15 dB. In contrast, the isolation degree of the antenna of the present invention is increased by 38.53%.

[0077] The isolation degree of the antenna proposed in Comparative Solution CN119133857A is 15 dB. In contrast, the isolation degree of the antenna of the present invention is increased by 38.53%.

[0078] Please refer to Figure 18 , Figure 18 which is the antenna gain curve of the present invention. Figure 18 In terms of antenna gain, the average gain of the antenna of the present invention in the frequency band of 3.3 GHz - 5.0 GHz is 13.76 dBi.

[0079] The average gain of the antenna proposed in the article "Dual - Polarized Spline - Loop Antenna Array With Tilt Angle Radiation for 5G Base Stations" by Y.-F. Lin, C.-C. Chang, C.-H. Chen, J.-Y. Xie, Y.-X. Zhuang, and H.-M. Chen is 11 dBi. In contrast, the average gain of the antenna of the present invention is increased by 38.53%.

[0080] The average gain of the prior art CN119133857A is 11.5 dBi. In contrast, the average gain of the antenna of the present invention is increased by 20%, and the peak gain reaches 15.64 dBi (appearing at 4.0 GHz).

[0081] The average gain of the prior art CN106876982A is 6.5 dBi. In contrast, the average gain of the antenna of the present invention is increased by 111.69%, and the peak gain reaches 15.64 dBi (appearing at 4.0 GHz).

[0082] In terms of aperture efficiency, through formula calculation, the aperture efficiency of the antenna of the present invention is 74.33%.

[0083] The aperture efficiency of the antenna proposed in the article "Dual - Polarized Spline - Loop Antenna Array With Tilt Angle Radiation for 5G Base Stations" by Y.-F. Lin, C.-C. Chang, C.-H. Chen, J.-Y. Xie, Y.-X. Zhuang, and H.-M. Chen is 25.56%. In contrast, the aperture efficiency of the antenna of the present invention is increased by approximately 190.73%.

[0084] The aperture efficiency of the comparative scheme CN119133857A is 24.879%. In contrast, the aperture efficiency of the antenna of the present invention is increased by approximately 198.77%.

[0085] Since the comparative scheme CN106876982A does not clearly give the antenna size, the size is speculated to be about 30 mm × 60 mm according to the relevant description and actual application scenario. The calculated aperture efficiency is 66%. In contrast, the aperture efficiency of the antenna of the present invention is increased by approximately 12.64%.

[0086] The comparison results of the broadband high - gain 5G base station antenna based on metasurface of this embodiment with the article "Dual - Polarized Spline - Loop Antenna Array With Tilt Angle Radiation for 5G Base Stations" by Y.-F. Lin, C.-C. Chang, C.-H. Chen, J.-Y. Xie, Y.-X. Zhuang, and H.-M. Chen, CN119133857A, and CN106876982A are shown in Tables 1, 2, and 3.

[0087] Table 1

[0088] Table 2

[0089] Table 3

[0090] It can be seen from Table 1, Table 2 and Table 3 that the antenna of this embodiment has the advantages of wide operating frequency band, high average gain, high aperture efficiency and high isolation.

[0091] Please refer to Figure 19 , Figure 19 which is the radiation pattern of the antenna of the present invention at the frequency point of 3.6 GHz and Phi = 90. Among them, Phi is the angle, Theta is the unit of horizontal angle, deg is the unit of vertical angle, and dBi is the unit of gain. In the figure, the main lobe is clear and prominent, and the energy concentration is good, which is conducive to the directional transmission of signals; the sidelobe level is relatively low, which can effectively suppress the interference in other directions; the shape of the radiation pattern is relatively regular, the radiation characteristics are stable, and it shows good consistency at different angles.

[0092] Please refer to Figure 20 , Figure 20 which is the radiation pattern of the antenna of the present invention at the frequency point of 3.6 GHz and Phi = 0. In the figure, the main lobe is prominent and concentrated, and the energy convergence effect is good, which is conducive to directional communication; the sidelobe level is relatively low, the interference in other directions is small, and the signal purity is high; the overall shape of the radiation pattern is regular, the radiation characteristics are stable, and the consistency is good at different angles, which can provide a stable and reliable signal coverage for communication.

[0093] Please refer to Figure 21 , Figure 21 which is the radiation pattern of the antenna of the present invention at the frequency point of 4.8 GHz and Phi = 90. In the figure, the main lobe is relatively obvious, and the energy concentration degree is relatively high, which is conducive to the directional transmission of signals; the sidelobe level is relatively low, which can effectively reduce the interference in other directions and ensure the signal quality; the overall graph is regular, the radiation characteristics are stable, and it has good consistency at different angles.

[0094] Please refer to Figure 22 , Figure 22 which is the radiation pattern of the antenna of the present invention at the frequency point of 4.8 GHz and Phi = 0. In the figure, the antenna has good directivity, the main lobe is narrow and highly directional, and it can concentrate energy for radiation; the sidelobe level is low, which can reduce interference; the front-to-back ratio is good, which can avoid the backward leakage of energy; the radiation characteristics in the horizontal direction are symmetric and stable, and the overall performance is excellent.

[0095] Therefore, the antenna of this embodiment has the advantages of wide operating frequency band, high average gain, high aperture efficiency and high isolation.

[0096] In terms of the operating frequency band, through the design of the metasurface layer in this embodiment, it is possible to effectively integrate and utilize multiple frequency band resources of 5G-NR, achieve a working bandwidth of 40.96%, and enable stable and efficient signal transmission. In a complex and changeable communication environment, it can ensure seamless network connection for users, greatly improving the reliability and universality of communication, and meeting the diverse communication application scenario requirements in the 5G era.

[0097] In terms of average gain and aperture efficiency, by leveraging the electromagnetic characteristics of the metasurface, the antenna in this embodiment can efficiently focus and enhance signals, thereby significantly increasing the antenna gain and achieving an average gain of 13.76 dBi. At the same transmit power, the signal can propagate over a longer distance and maintain a stronger intensity, effectively overcoming the problem of signal attenuation in traditional antennas. At the same time, in terms of the physical size of the antenna, a higher aperture efficiency is achieved within a smaller footprint, with the aperture efficiency reaching 74.33%. This means that in limited space resources, the antenna aperture can be more effectively utilized to radiate and receive signals, reducing energy waste and scattering, further enhancing the overall performance of the antenna, and providing a strong guarantee for achieving efficient communication transmission.

[0098] In terms of isolation, in the complex operating environment of a multi-antenna system, through the ingenious array design of cross dipoles in this invention, a high isolation degree between antennas is ensured, with the isolation degree being greater than 20.78 dB. Even when multiple antennas are operating simultaneously and signal transmission is frequent, the signals between different antennas can maintain a high degree of independence, effectively avoiding the problem of mutual interference and greatly improving the capacity and reliability of the communication system.

[0099] In summary, the antenna in this embodiment sets a metasurface layer in the central unit, realizes a wide operating frequency band through the metasurface structure, can integrate and utilize 5G-NR frequency band resources, ensures seamless network connection, and improves the reliability and universality of communication; achieves high antenna gain and high aperture efficiency by leveraging the electromagnetic characteristics of the metasurface, can focus and enhance signals, the signal propagates farther and has a greater intensity at the same transmit power, and at the same time, a high aperture efficiency can be obtained with a small area, reducing energy waste and scattering; adopts a cross dipole array design with low-frequency auxiliary units distributed diagonally and high-frequency auxiliary units distributed diagonally, ensuring a high isolation degree, enabling signals to be independent when multiple antennas are operating, avoiding interference, and improving the system capacity and reliability.

[0100] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A broadband high-gain 5G base station antenna based on metasurface, characterized in that, Comprising: A system floor (1), a first low-frequency auxiliary unit (2), a second low-frequency auxiliary unit (3), a first high-frequency auxiliary unit (4), a second high-frequency auxiliary unit (5), a central unit (6), and a feeding network (7), wherein, The first low-frequency auxiliary unit (2), the second low-frequency auxiliary unit (3), the first high-frequency auxiliary unit (4), and the second high-frequency auxiliary unit (5) are arranged in an array on a first surface of the system floor (1) and surround the central unit (6). The first low-frequency auxiliary unit (2) and the second low-frequency auxiliary unit (3) are diagonally distributed, and the first high-frequency auxiliary unit (4) and the second high-frequency auxiliary unit (5) are diagonally distributed; The central unit (6) includes a metasurface layer (61) and a dual-polarization unit. The dual-polarization unit is disposed on the first surface of the system floor (1), and the metasurface layer (61) is fixed on the dual-polarization unit; The feeding network (7) is disposed on a second surface of the system floor (1) and is respectively connected to the first low-frequency auxiliary unit (2), the second low-frequency auxiliary unit (3), the first high-frequency auxiliary unit (4), the second high-frequency auxiliary unit (5), and the central unit (6) through coaxial cables.

2. The broadband high-gain 5G base station antenna based on metasurface according to claim 1, characterized in that, The metasurface layer (61) includes a first dielectric substrate (611) and a plurality of cross-shaped patches (612), wherein, The plurality of cross-shaped patches (612) are arranged in a cross array on a surface of the first dielectric substrate (611) away from the system floor (1); Each cross-shaped patch (612) is formed by a solid cross-shaped patch (6121) and four hollow symmetric M-shaped patches (6122) connected to four ends of the solid cross-shaped patch (6121). Each hollow symmetric M-shaped patch (6122) has two mirror-symmetric M-shaped units, and each M-shaped unit is formed by bending a microstrip line.

3. The broadband high-gain 5G base station antenna based on a metasurface according to claim 2, characterized in that, Each branch of the solid cross-shaped patch (6121) is equivalent to an inductor; In each M-shaped unit, each sub-microstrip line extending along a branch of the solid cross-shaped patch (6121) is equivalent to an inductor, and the blank part between two sub-microstrip lines is equivalent to a capacitor; the blank part between the two M-shaped units is equivalent to a capacitor; The equivalent circuit of the hollow symmetric M-shaped patch (6122) is a series-connected capacitor and inductor.

4. The broadband high-gain 5G base station antenna based on a metasurface according to claim 1, characterized in that, The dual-polarization unit includes a first reflection layer (62) and a first feeding balun (63), wherein, The metasurface layer (61) is fixed to one side of the first reflection layer (62) through a plurality of studs (64); The first feeding balun (63) is disposed on the other side of the first reflection layer (62) and is fixed to the first surface of the system floor (1) through a plug; The first feeding balun (63) is connected to the feeding network (7) through a coaxial cable.

5. The metasurface-based broadband high-gain 5G base station antenna according to claim 4, wherein The first reflection layer (62) includes a second dielectric substrate (621) and four spindle-shaped patches (622), wherein, The four spindle-shaped patches (622) are symmetrically arranged on the surface of the second dielectric substrate (621) away from the system floor (1); Each spindle-shaped patch (622) includes a first straight segment (6221) and two first smooth curve segments (6222). The two first smooth curve segments (6222) extend from the two ends of the first straight segment (6221) until they intersect to form a closed axisymmetric figure; the first straight segments (6221) of the four spindle-shaped patches (622) are close to each other and pairwise opposite.

6. The broadband high-gain 5G base station antenna based on a metasurface according to claim 4, characterized in that, The first feeding balun (63) includes a first central feeding component (631) and a second central feeding component (632) that are vertically crossed in space, where The first central feeding component (631) includes a third dielectric substrate (6311), a first microstrip feeding line (6312), a first parasitic patch (6313), and a second parasitic patch (6314); the third dielectric substrate (6311) is fixed on the system floor (1) by an insert, the first microstrip feeding line (6312) is arranged on the first surface of the third dielectric substrate (6311) and is connected to the feeding network (7) through a coaxial cable, and the first parasitic patch (6313) and the second parasitic patch (6314) are symmetrically distributed on the second surface of the third dielectric substrate (6311); The second central feeding component (632) includes a fourth dielectric substrate (6321), a second microstrip feeding line (6322), a third parasitic patch (6323), and a fourth parasitic patch (6324); the fourth dielectric substrate (6321) is fixed on the system floor (1) by an insert, the second microstrip feeding line (6322) is arranged on the first surface of the fourth dielectric substrate (6321) and is connected to the feeding network (7) through a coaxial cable, and the third parasitic patch (6323) and the fourth parasitic patch (6324) are symmetrically distributed on the second surface of the fourth dielectric substrate (6321); The first microstrip feeding line (6312) and the second microstrip feeding line (6322) form an electromagnetic coupling structure in the crossing area, constituting the feeding network of the dual-polarization unit.

7. The metasurface-based broadband high-gain 5G base station antenna according to claim 1, wherein The structures of the first low-frequency auxiliary unit (2) and the second low-frequency auxiliary unit (3) are the same, and both include a second reflection layer (21) and a second feeding balun (22) fixed between the second reflection layer (21) and the system floor (1), where The second reflection layer (21) includes a fifth dielectric substrate (211), a hollow diamond-shaped patch (212), and four nested willow-leaf-shaped patches (213); the hollow diamond-shaped patch (212) and the four nested willow-leaf-shaped patches (213) are disposed on a surface of the fifth dielectric substrate (211) away from the system floor (1); the four nested willow-leaf-shaped patches (213) are arranged in central symmetry and are located inside the hollow diamond-shaped patch (212); each nested willow-leaf-shaped patch (213) includes a nested inner ring (2131) and outer ring (2132), and the inner ring (2131) and the outer ring (2132) have the same shape; The second feeding balun (22) includes a first low-frequency feeding component (221) and a second low-frequency feeding component (222) that are vertically crossed in space; The first low-frequency feeding component (221) includes a sixth dielectric substrate (2211), a third microstrip feeding line (2212), a fifth parasitic patch (2213), and a sixth parasitic patch (2214); the sixth dielectric substrate (2211) is fixed to the system floor (1) by a plug, the third microstrip feeding line (2212) is disposed on a first surface of the sixth dielectric substrate (2211) and is connected to the feeding network (7) through a coaxial cable, and the fifth parasitic patch (2213) and the sixth parasitic patch (2214) are symmetrically distributed on a second surface of the sixth dielectric substrate (2211); The second low-frequency feeding component (222) includes a seventh dielectric substrate (2221), a fourth microstrip feeding line (2222), a seventh parasitic patch (2223), and an eighth parasitic patch (2224); the seventh dielectric substrate (2221) is fixed to the system floor (1) by a plug, the fourth microstrip feeding line (2222) is disposed on a first surface of the seventh dielectric substrate (2221) and is connected to the feeding network (7) through a coaxial cable, and the seventh parasitic patch (2223) and the eighth parasitic patch (2224) are symmetrically distributed on a second surface of the seventh dielectric substrate (2221); The third microstrip feeding line (2212) and the fourth microstrip feeding line (2222) form an electromagnetic coupling structure in the crossing area to constitute a radiation network of the low-frequency auxiliary unit.

8. The metasurface-based wideband high-gain 5G base station antenna according to claim 1, wherein The first high-frequency auxiliary unit (4) and the second high-frequency auxiliary unit (5) have the same structure, and both include a third reflection layer (41) and a third feeding balun (42) fixedly disposed between the third reflection layer (41) and the system floor (1), where, The third reflection layer (41) includes an eighth dielectric substrate (411) and four windmill blade-shaped patches (412), and the four windmill blade-shaped patches (412) are arranged in central symmetry on the surface of the eighth dielectric substrate (411); The third feeding balun (42) includes a first high-frequency feeding component (421) and a second high-frequency feeding component (422) that are vertically crossed in space; The first high-frequency feeding component (421) includes a ninth dielectric substrate (4211), a fifth microstrip feeding line (4212), a ninth parasitic patch (4213), and a tenth parasitic patch (4214); the ninth dielectric substrate (4211) is fixed on the system floor (1) by an insert, the fifth microstrip feeding line (4212) is disposed on a first surface of the ninth dielectric substrate (4211) and is connected to the feeding network (7) through a coaxial cable, and the ninth parasitic patch (4213) and the tenth parasitic patch (4214) are symmetrically distributed on a second surface of the ninth dielectric substrate (4211); The second high-frequency feeding component (422) includes a tenth dielectric substrate (4221), a sixth microstrip feeding line (4222), an eleventh parasitic patch (4223), and a twelfth parasitic patch (4224); the tenth dielectric substrate (4221) is fixed on the system floor (1) by an insert, the sixth microstrip feeding line (4222) is disposed on a first surface of the tenth dielectric substrate (4221) and is connected to the feeding network (7) through a coaxial cable, and the eleventh parasitic patch (4223) and the twelfth parasitic patch (4224) are symmetrically distributed on a second surface of the tenth dielectric substrate (4221); The fifth microstrip feeding line (4212) and the sixth microstrip feeding line (4222) form an electromagnetic coupling structure in the crossing area to constitute the feeding network of the high-frequency auxiliary unit.

9. The broadband high-gain 5G base station antenna based on a metasurface according to claim 1, wherein The feeding network (7) includes a first sub-network (71) and a second sub-network (72), wherein, The first sub-network (71) is used for connecting the microstrip feeding lines with a first polarization angle and includes a first Wilkinson power divider (WPD1), a second Wilkinson power divider (WPD2), a first T-shaped power divider (T1), and a second T-shaped power divider (T2); an input end of the first Wilkinson power divider (WPD1) serves as a first external port (P1) of the feeding network (7), a first output end is connected to an input end of the second Wilkinson power divider (WPD2), and a second output end is connected to an input end of the first T-shaped power divider (T1); a first output end of the first T-shaped power divider (T1) serves as a first output port (H1) of the feeding network (7), and a second output end is connected to an input end of the second T-shaped power divider (T2); first and second output ends of the second T-shaped power divider (T2) respectively serve as a second output port (H2) and a third output port (H3) of the feeding network (7); first and second output ends of the second Wilkinson power divider (WPD2) respectively serve as a fourth output port (H4) and a fifth output port (H5) of the feeding network (7); The second sub-network (72) is used to connect a microstrip feeder with a second polarization angle, and includes a third Wilkinson power divider (WPD3), a fourth Wilkinson power divider (WPD4), a third T-shaped power divider (T3), and a fourth T-shaped power divider (T4); the input end of the third Wilkinson power divider (WPD3) serves as the second external port (P2) of the feeding network (7), the first output end is connected to the input end of the fourth Wilkinson power divider (WPD4), and the second output end is connected to the input end of the third T-shaped power divider (T3); the first output end of the third T-shaped power divider (T3) serves as the sixth output port (H6) of the feeding network (7), and the second output end is connected to the input end of the fourth T-shaped power divider (T4); the first output end and the second output end of the fourth T-shaped power divider (T4) respectively serve as the seventh output port (H7) and the eighth output port (H8) of the feeding network (7); the first output end and the second output end of the fourth Wilkinson power divider (WPD4) respectively serve as the ninth output port (H9) and the tenth output port (H10) of the feeding network (7); The central unit (6) is connected to the first output port (H1) and the sixth output port (H6) respectively through two coaxial cables; the first low-frequency auxiliary unit (2) is connected to the second output port (H2) and the seventh output port (H7) respectively through two coaxial cables; the second low-frequency auxiliary unit (3) is connected to the third output port (H3) and the eighth output port (H8) respectively through two coaxial cables; the first high-frequency auxiliary unit (4) is connected to the fourth output port (H4) and the ninth output port (H9) respectively through two coaxial cables; the second high-frequency auxiliary unit (5) is connected to the fifth output port (H5) and the tenth output port (H10) respectively through two coaxial cables.

10. The broadband high-gain 5G base station antenna based on metasurface according to claim 1, characterized in that, Among the first low-frequency auxiliary unit (2), the second low-frequency auxiliary unit (3), the first high-frequency auxiliary unit (4), and the second high-frequency auxiliary unit (5), the distance between the centers of two adjacent auxiliary units is 0.6 times the wavelength, and the distance between the center of each auxiliary unit and the center of the central unit (6) is 0.75 times the wavelength.

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