Low-profile common-caliber base station antenna

Abstract

The invention discloses a low-profile common-caliber base station antenna which comprises a metasurface antenna unit, a low-frequency cross dipole antenna is arranged on the upper end face of the metasurface antenna unit, and the low-frequency cross dipole antenna is arranged on the lower end face of the metasurface antenna unit while the metasurface antenna unit provides high-frequency-band signal radiation and performs wide-angle beam scanning. And the low-frequency cross dipole antenna is used for providing low-frequency-band signal radiation and carrying out fixed beam scanning so as to realize multi-frequency-band signal coverage. According to the invention, the frequency selectivity and the high and low frequency collaborative radiation performance of the cross dipole antenna can be improved.

Description

Technical Field

[0001] This application belongs to the field of mobile communication technology, specifically relating to a low-profile common-aperture base station antenna. Background Technology

[0002] Traditional base station antennas typically employ a single-band, fixed-beam design, resulting in limited coverage and frequency bands. While frequency selective surfaces (FSS) are commonly used for isolation of multi-band antennas, they increase the antenna profile height, limiting their application in modern communications. With the rise of 5G communication technology, base station antennas need to support wider frequency bands (such as the N78 band), higher communication rates, and more complex multi-user communication functions, placing higher demands on base station antenna design. Therefore, existing technologies face problems such as excessively high profiles and insufficient frequency band coverage, requiring novel designs to achieve wideband, low-profile, and high-efficiency base station antenna solutions. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this application is to provide a low-profile common-aperture base station antenna, which can improve the frequency selectivity and high-low frequency cooperative radiation performance of the cross dipole antenna.

[0004] To achieve the above objectives, this application provides the following technical solution: A low-profile common-aperture base station antenna, the antenna comprising: a metasurface antenna element, wherein a low-frequency crossed dipole antenna is disposed on the upper surface of the metasurface antenna element, wherein while the metasurface antenna element provides high-frequency signal radiation and performs wide-angle beam scanning, the low-frequency crossed dipole antenna is used to provide low-frequency signal radiation and perform fixed beam scanning to achieve multi-frequency signal coverage. Optionally, the metasurface antenna element includes: multiple stacked dielectric substrates. The plurality of stacked dielectric substrates include a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate, which are arranged in accordance with the propagation direction of the electromagnetic waves emitted by the low-frequency cross dipole antenna.

[0005] Optionally, a first mesh-like metal layer is disposed on the upper surface of the first dielectric substrate, and the low-frequency crossed dipole antenna is disposed on the first mesh-like metal layer. The first mesh-like metal layer is used to guide and regulate the propagation of electromagnetic waves emitted by the low-frequency crossed dipole antenna.

[0006] Optionally, a second mesh-like metal layer is disposed between the first dielectric substrate and the second dielectric substrate, the second mesh-like metal layer being used to couple electromagnetic waves guided and controlled based on the first mesh-like metal layer.

[0007] Optionally, a metal ground layer is disposed between the second dielectric substrate and the third dielectric substrate, the metal ground layer being used to reflect and shield the coupled electromagnetic waves.

[0008] Optionally, a feeder is provided at the bottom of the metal ground layer.

[0009] Optionally, the side length of the metal ring in the second mesh-like metal layer is half that of the first mesh-like metal layer.

[0010] Optionally, the third dielectric substrate has orthogonally arranged coupling grooves distributed alternately.

[0011] Optionally, the coupling groove may take any of the following geometric shapes: rectangle, circle, triangle, and ring.

[0012] Optionally, the low-frequency crossed dipole antenna includes: a radiating body, which is fixedly connected to the metasurface antenna unit via a 3D-printed bracket; an SMA connector is provided on the lower end face of the radiating body; and multiple identical dipole arms with embedded FSS structures are provided on the upper end face of the radiating body, with microstrip feed lines provided on the dipole arms, wherein the dipole arms are connected to the outer conductor of the SMA connector, and the microstrip feed lines are connected to the inner conductor of the SMA connector.

[0013] Compared with the prior art, the beneficial effects of this application are as follows: This application effectively improves the frequency selectivity and radiation performance of a cross-dipole antenna by introducing different types of frequency-selective surface structures. The loading of the FSS not only enhances the transmission efficiency of high-frequency signals but also, to a certain extent, suppresses the blocking effect of low-frequency structures on the high-frequency metasurface antenna, achieving high isolation and good coordination between low-frequency and high-frequency antenna elements. Overall, this application significantly improves the multi-band compatibility, radiation efficiency, and directional control capability of the antenna system, contributing to the construction of low-profile, high-performance common-aperture base station antennas. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of a low-profile common-aperture base station antenna provided in one embodiment of this application; Figure 2 yes Figure 1 The diagram shows the structure of a low-frequency crossed dipole antenna. Figure 3 yes Figure 1 A top view of the metasurface antenna element in the antenna shown. Figure 4 yes Figure 3A top view of the first mesh-like metal layer M1 and the second mesh-like metal layer M2 in the metasurface antenna element shown; Figure 5 yes Figure 3 Top view of the metasurface antenna element shown; Figure 6 This is a schematic diagram of the active VSWR of a high-frequency metasurface antenna at different scanning angles in the N78 band; Figure 7 This is a schematic diagram of the radiative characteristics of a high-frequency metasurface antenna in the 1.7-2.7 GHz frequency band; Figure 8 This is a schematic diagram of a traditional cross dipole and a cross dipole structure with different FSS loaded on the dipole arms; Figure 9 yes Figure 6 A schematic diagram comparing the transmission coefficients of the dipole arms of three different cross-dipole structures in China; Figure 10 yes Figure 6 Schematic diagram of reflection coefficients and cross isolation of three types of cross dipole structures; Figure 11 This is a schematic diagram of the electric field distribution of a conventional cross dipole antenna without an FSS shielding high-frequency metasurface antenna. Figure 12 This is a schematic diagram of the electric field distribution radiated by a cross-dipole transmission high-frequency metasurface antenna loaded with FSS. Figure 13 This is a schematic diagram of simulation and test data of the reflection coefficient and cross isolation of the low-frequency cross dipole antenna in a low-profile common-aperture base station antenna. Figure 14 This is a schematic diagram of simulation data on the isolation between the low-frequency crossed dipole antenna and the high-frequency metasurface antenna element in a low-profile common-aperture base station antenna. Figure 15 This is a schematic diagram of the test data for the isolation between the low-frequency crossed dipole antenna and the high-frequency metasurface antenna element in a low-profile co-aperture base station antenna. Figure 16 This is a schematic diagram of the radiation direction of a dipole antenna at a frequency of 1.8 GHz; Figure 17 This is a schematic diagram of the radiation direction of a dipole antenna at a frequency of 2.2 GHz; Figure 18 This is a schematic diagram of the radiation direction of a dipole antenna at a frequency of 2.6 GHz; Figure 19 This is a schematic diagram of the active VSWR simulation data of the central element in the high-frequency metasurface antenna array of a low-profile common-aperture base station antenna; Figure 20This is a schematic diagram of the active VSWR test data of the central element in a high-frequency metasurface antenna array in a low-profile common-aperture base station antenna. Figure 21 This is a schematic diagram of active VSWR simulation data for edge elements in a high-frequency metasurface antenna array in a low-profile common-aperture base station antenna. Figure 22 This is a schematic diagram of active VSWR test data for edge elements in a high-frequency metasurface antenna array in a low-profile co-aperture base station antenna. Figure 23 This is a schematic diagram of the E-plane beam scanning simulation data of a high-frequency metasurface antenna array in a low-profile common-aperture base station antenna; Figure 24 This is a schematic diagram of E-plane beam scanning test data for a high-frequency metasurface antenna array in a low-profile, common-aperture base station antenna. Figure 25 This is a schematic diagram of simulation data for H-plane beam scanning of a high-frequency metasurface antenna array in a low-profile common-aperture base station antenna. Figure 26 This is a schematic diagram of E-plane beam scanning test data for a high-frequency metasurface antenna array in a low-profile, common-aperture base station antenna. Detailed Implementation

[0015] Specific embodiments of this application will now be described in detail with reference to the accompanying drawings. While specific embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0016] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0017] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments, and the accompanying drawings do not constitute a limitation on the embodiments of this application.

[0018] Figure 1This is a schematic diagram of a low-profile common-aperture base station antenna provided in an exemplary embodiment of this application, as shown below. Figure 1 As shown, the antenna includes a metasurface antenna element, and a low-frequency crossed dipole antenna is disposed on the upper surface of the metasurface antenna element. While the metasurface antenna element provides high-frequency signal radiation and performs wide-angle beam scanning, the low-frequency crossed dipole antenna is used to provide low-frequency signal radiation and perform fixed beam scanning to achieve multi-frequency signal coverage. The antenna provided in this embodiment achieves multi-band signal coverage through the coordinated operation of a metasurface antenna element and a low-frequency crossed dipole antenna. The metasurface antenna element provides precise radiation and wide-angle beam scanning for high-frequency signals, meeting the high data rate communication requirements of 5G and other technologies. The low-frequency crossed dipole antenna ensures stable transmission of low-frequency signals and provides fixed beam scanning, serving 2G / 3G / 4G communication systems. Combining these two elements in the same antenna array not only avoids mutual interference but also significantly reduces the antenna profile height, thereby improving the antenna system's integration, frequency coverage, and radiation efficiency.

[0019] In another exemplary embodiment, such as Figure 1 As shown, the metasurface antenna element includes: Multiple dielectric substrates are stacked together. For example, the multiple stacked dielectric substrates include a first dielectric substrate D1, a second dielectric substrate D2, and a third dielectric substrate D3 (the number of dielectric substrates can be adjusted according to actual needs). The first dielectric substrate D1, the second dielectric substrate D2, and the third dielectric substrate D3 are arranged according to the propagation direction of the electromagnetic waves emitted by the low-frequency cross dipole antenna.

[0020] In this embodiment, the first dielectric substrate D1, the second dielectric substrate D2, and the third dielectric substrate D3 are arranged according to the propagation direction of the electromagnetic wave emitted by the low-frequency cross dipole antenna. Figure 1In this multi-layered structure, electromagnetic waves (propagating from top to bottom) are precisely arranged to effectively guide and control them, ensuring efficient signal radiation across different frequency bands. The low-frequency crossed dipole antenna provides stable radiation in the low-frequency band and achieves fixed beam scanning, while the metasurface antenna provides signal radiation in the high-frequency band and performs wide-angle beam scanning. This multi-layered design not only effectively achieves high isolation between low-frequency and high-frequency signals but also ensures that the low-frequency and high-frequency antenna elements are physically integrated and electromagnetically independent. This allows the antennas to achieve common-aperture radiation of multi-frequency signals without mutual interference, significantly improving the spectral efficiency and communication performance of the antenna system. Furthermore, by independently managing and coordinating signals in different frequency bands, the antenna system can better adapt to the requirements of high-speed communication systems such as 5G and future 6G for multi-band, high-efficiency, and low-profile designs.

[0021] In another exemplary embodiment, a first mesh-like metal layer M1 is disposed on the upper surface of the first dielectric substrate, and the low-frequency cross-dipole antenna is disposed on the first mesh-like metal layer M1. The first mesh-like metal layer M1 is used to guide and regulate the propagation of electromagnetic waves emitted by the low-frequency cross-dipole antenna.

[0022] In this embodiment, the first mesh-like metal layer M1 is located on the upper surface of the first dielectric substrate D1 and supports the low-frequency crossed dipole antenna. Its main function is to regulate the propagation direction and radiation mode of the electromagnetic waves emitted by the low-frequency crossed dipole antenna by utilizing the reflection and transmission characteristics of electromagnetic waves. The periodic structure of the first mesh-like metal layer M1 can form effective electromagnetic wave propagation paths at different frequencies. With appropriate design, the radiation efficiency of the signal can be enhanced, while controlling the shape and direction of the beam.

[0023] Specifically, the first mesh-like metal layer M1 functions by guiding electromagnetic waves through its electromagnetic properties, thereby optimizing the radiation of the low-frequency crossed dipole antenna, reducing energy loss, and improving radiation directivity. This mesh-like metal layer structure works in conjunction with the low-frequency crossed dipole antenna to achieve frequency selectivity and beam control, ensuring stable radiation of low-frequency signals and maintaining a good radiation pattern. Furthermore, the first mesh-like metal layer M1 can also work synergistically with other parts of the antenna to further improve the isolation of low-frequency signals, reduce interference between different frequency bands, and thus enhance the overall performance of the antenna system. In summary, the first mesh-like metal layer M1 not only optimizes low-frequency signal radiation but also provides the antenna system with more precise electromagnetic wave control and adjustment capabilities.

[0024] In summary, the metasurface antenna element, through its multi-layer composite structure design, achieves both high-gain, high-scanning beamwidth radiation in high-frequency bands (such as N78) and stable, reliable signal transmission in low-frequency bands, while maintaining a low profile and compact size. Through the coordinated operation of the high- and low-frequency elements, this structure not only ensures high isolation and radiation efficiency between different frequency bands but also possesses excellent beam direction control capabilities, effectively improving the overall system's spectrum utilization and communication performance. This meets the comprehensive requirements of 5G base stations for wideband, integrated, and high-performance antenna systems, achieving a truly multi-frequency, common-aperture compatible design.

[0025] In another exemplary embodiment, a second mesh-like metal layer M2 is disposed between the first dielectric substrate D1 and the second dielectric substrate D2. The second mesh-like metal layer M2 is used to couple electromagnetic waves guided and controlled based on the first mesh-like metal layer M1.

[0026] In this embodiment, the second mesh-like metal layer M2 is located between the first dielectric substrate D1 and the second dielectric substrate D2, and is mainly used to effectively couple the electromagnetic waves guided and regulated by the first mesh-like metal layer M1. The design structure and layout of the second mesh-like metal layer M2 enable it to form an electromagnetic coupling effect with the first mesh-like metal layer M1, transmitting electromagnetic waves from the first mesh-like metal layer M1 to the second mesh-like metal layer M2, and further regulating the propagation characteristics and energy distribution of the electromagnetic waves in the process.

[0027] Specifically, the second mesh-like metal layer M2 effectively enhances the propagation and coupling efficiency of electromagnetic waves through its mesh-like metal structure. This allows for more precise control of electromagnetic waves guided by the first mesh-like metal layer M1 across different frequency ranges, optimizing the antenna's radiation performance. Furthermore, the second mesh-like metal layer M2 not only guides electromagnetic wave energy to the next layer but also adjusts the propagation mode of the electromagnetic waves, ensuring more efficient signal transmission within the antenna's operating frequency band. Moreover, the second mesh-like metal layer M2 can optimize frequency response by adjusting its structural dimensions and arrangement, avoiding inter-band interference and improving the isolation of multi-band signals.

[0028] In summary, the second mesh-like metal layer M2 not only improves the coupling efficiency of electromagnetic waves, but also ensures the high efficiency of electromagnetic energy transfer between different dielectric layers, promotes the coordinated operation of the entire antenna unit, and helps to achieve efficient beam control and optimized frequency response.

[0029] In another exemplary embodiment, a metal ground layer M3 is disposed between the second dielectric substrate and the third dielectric substrate. The metal ground layer M3 is used to reflect and shield the coupled electromagnetic waves to enhance the radiation efficiency of the low-frequency cross dipole antenna.

[0030] In this embodiment, a metal ground layer M3 is disposed between the second dielectric substrate D2 and the third dielectric substrate D3. Its main function is to reflect and shield electromagnetic waves coupled through the second mesh-like metal layer M2. The metal ground layer M3, with its high conductivity, effectively reflects the energy of the electromagnetic waves back to the antenna's radiation area, thereby enhancing radiation efficiency. Specifically, when electromagnetic waves coupled through the second mesh-like metal layer M2 propagate downwards, the presence of the metal ground layer M3 ensures that these electromagnetic waves are effectively reflected, guaranteeing that the energy of the electromagnetic waves is not lost or scattered in unwanted directions, but is guided to the target radiation area.

[0031] Furthermore, the metal ground layer M3 also acts as a shield, helping to reduce external electromagnetic interference and ensuring more stable and clear signal transmission for the low-frequency crossed dipole antenna. By shielding against external interference, the metal ground layer M3 ensures that the antenna's operating frequency band is not affected by signals from other frequency bands, thus maintaining high signal quality and radiation efficiency. During the radiation process of the low-frequency crossed dipole antenna, the reflection effect of the metal ground layer M3 not only improves the radiation efficiency of low-frequency signals but also effectively enhances the signal directivity, enabling the antenna to provide more stable and efficient signal coverage at lower frequencies.

[0032] In summary, the metal ground layer M3 improves the radiation efficiency of the low-frequency crossed dipole antenna through reflection and shielding functions, optimizes the propagation path of electromagnetic waves, and reduces signal interference, thereby enhancing the overall performance of the antenna and making it more suitable for multi-band and high-efficiency communication needs.

[0033] In this application, the first mesh-like metal layer M1, the second mesh-like metal layer M1, and the metal ground layer M3 are arranged sequentially along the electromagnetic wave propagation direction (e.g., ...). Figure 3 and Figure 4 As shown, the antenna effectively guides, modulates, and reflects electromagnetic waves. Specifically, the first mesh-like metal layer M1 guides and regulates the propagation path of electromagnetic waves through its periodic structure, making the radiation of low-frequency signals more stable. The second mesh-like metal layer M2 further optimizes the transmission and energy distribution of electromagnetic waves through coupling, ensuring efficient signal transmission between different dielectric layers. The metal ground layer M3 serves as a reflector and shield, reflecting electromagnetic waves back to the radiation area to enhance the radiation efficiency of low-frequency signals and shielding external electromagnetic interference to ensure the stability of the antenna signal. Through this sequentially arranged structure, the entire antenna can achieve efficient signal transmission and radiation in different frequency bands, while reducing signal loss and interference, improving the antenna's radiation efficiency and spectral utilization, and contributing to wider frequency band coverage and more precise beam control.

[0034] In another exemplary embodiment, a feeder M4 is provided at the bottom end of the metal ground layer M3.

[0035] In this embodiment, placing the feed line M4 at the bottom of the metal ground layer M3 not only optimizes the signal injection method but also improves the overall performance of the antenna. As a power transmission line, the feed line is primarily used to transmit external electrical signals to the antenna element. Positioning the feed line at the bottom of the metal ground layer M3 ensures effective signal transmission. The metal ground layer M3 provides a stable ground plane for the feed line, allowing it to achieve good electromagnetic compatibility, reducing signal reflection loss, and ensuring that electrical signals are transmitted smoothly and efficiently to the antenna radiating element.

[0036] Specifically, placing a feed line at the bottom of the metal ground layer M3 helps optimize the propagation path of electromagnetic waves, ensuring that the injected electromagnetic waves can directly act on the antenna structure, avoiding unnecessary losses and interference. Furthermore, the reflection effect of the metal ground layer M3 also plays a crucial role in this process. The feed line M4, working in conjunction with the metal ground layer M3 and other dielectric layers, enhances the radiation efficiency of the low-frequency crossed dipole antenna and further ensures the stability and directivity of the electromagnetic waves.

[0037] In summary, placing the feeder M4 at the bottom of the metal ground layer M3 not only ensures efficient transmission of electromagnetic waves, but also optimizes the overall performance of the antenna through the good grounding and reflection shielding function of the metal ground layer M3, thereby improving the signal quality, radiation efficiency, and multi-band compatibility of the antenna system.

[0038] In another exemplary embodiment, the side length of the metal ring of the second mesh-like metal layer M2 is half that of the first mesh-like metal layer M1.

[0039] In this embodiment, by setting the side length of the metal ring of the second mesh-like metal layer M2 to half that of the first mesh-like metal layer M1, several advantages are achieved. First, it helps to adjust the antenna's operating frequency. A smaller metal ring size typically increases its resonant frequency. Therefore, the smaller size of the second mesh-like metal layer M2 allows the resonant frequency of the second layer antenna to be higher than that of the first layer, thus achieving good separation between different frequency bands and avoiding frequency interference. Second, by adjusting the side length ratio of the metal ring, the antenna's bandwidth and frequency selectivity can be optimized. A smaller metal ring allows the antenna to exhibit different resonant characteristics at multiple frequencies, which helps improve the antenna's performance in multi-band systems, especially in the synergistic effect between low-frequency and high-frequency signals. Third, it reduces mutual interference. The first mesh-like metal layer M1 is larger and mainly used for lower-frequency signal radiation. The smaller size of the second mesh-like metal layer M2 helps to reduce interference to low-frequency signals during the transmission of high-frequency signals. This application sets the side lengths of the metal rings of the first mesh metal layer M1 and the second mesh metal layer M2 to different sizes, which can ensure good isolation between low-frequency and high-frequency antennas, thereby optimizing the multi-band performance of the antenna, enhancing its working efficiency at different frequencies, and thus improving the overall communication quality of the antenna.

[0040] In another exemplary embodiment, such as Figure 5 As shown, the third dielectric substrate D3 has orthogonally arranged coupling grooves distributed in an alternating manner.

[0041] In this embodiment, by setting coupling slots, the radiation characteristics and frequency response of the antenna can be optimized through electromagnetic coupling. Specifically, through precise slot arrangement, the resonant frequency and bandwidth of the antenna can be effectively adjusted, enhancing signal transmission efficiency and enabling multi-band coexistence, thereby improving the antenna's performance. Furthermore, coupling slots can improve the antenna's radiation efficiency and enhance signal transmission and reception capabilities. Moreover, the staggered and orthogonal slot structure helps reduce interference between slots, optimize signal quality, and improve radiation efficiency, thus achieving efficient signal coverage and a wider frequency range.

[0042] It should be noted that coupling slots can take various geometric shapes, such as rectangles, circles, triangles, and rings, but these shapes are only examples and not limited to these. However, practical verification has shown that rectangular coupling slots perform best in optimizing electromagnetic wave coupling, improving signal transmission efficiency, and controlling frequency response. Their advantages lie in their good resonant characteristics, excellent electromagnetic wave propagation performance, and simple structure that is easy to manufacture. Specifically, by adjusting the length and width of the rectangular coupling slot, the resonant frequency can be precisely controlled, providing a uniform electric field distribution, reducing signal loss, and improving coupling efficiency. Furthermore, rectangular slots exhibit excellent bandwidth and frequency band isolation performance, effectively avoiding interference between different frequency bands, thus ensuring stable signal transmission. Because their size can be flexibly adjusted, rectangular coupling slots can meet different application requirements, especially in multi-band systems, maximizing antenna performance and stability. Therefore, choosing a rectangular coupling slot not only meets multi-band signal coverage requirements but also significantly improves antenna radiation efficiency and signal stability.

[0043] In another exemplary embodiment, such as Figure 2 As shown, the low-frequency crossed dipole antenna includes a radiating body, which is fixedly connected to the metasurface antenna unit via a 3D-printed bracket; the lower end face of the radiating body is provided with an SMA connector (for example, two connectors can be provided); the upper end face of the radiating body is provided with multiple dipole arms (for example, four arms) with identical structures and embedded with an FSS structure, and microstrip feed lines are provided on the dipole arms, wherein the dipole arms are connected to the outer conductor of the SMA connector, and the microstrip feed lines are connected to the inner conductor of the SMA connector.

[0044] In this embodiment, the operation of the low-frequency crossed dipole antenna is based on the coupling relationship between the radiating body, the SMA connector, the dipole arms, and the microstrip feed line. First, the lower end face of the radiating body fixes the antenna to the first mesh-like metal layer M1 via the SMA connector, ensuring the structural stability of the antenna. The upper end face of the radiating body has four dipole arms with embedded FSS (Frequency Selective Surface) structures. These dipole arms serve as the antenna's radiating elements, connected to the outer conductor of the SMA connector via their outer conductors, enabling the transmission of radiated signals. The microstrip feed line connects to the inner conductor of the SMA connector via its inner conductor, providing electrical signals to the dipole arms and exciting them to radiate through coupling. The design of the FSS structure helps optimize frequency selectivity, enabling the antenna to provide excellent radiation characteristics within a specific frequency band.

[0045] In summary, this design effectively reduces interference from low-frequency antennas to high-frequency signals while simultaneously achieving the radiation and transmission of low-frequency signals. Overall, the low-frequency crossed dipole antenna, through the coordinated operation of the radiating body, dipole arms, microstrip feed line, and SMA connector, can achieve stable and efficient signal radiation in the low-frequency band.

[0046] Based on the above description of the antenna structure, this application combines... Figures 6 to 26 The performance of the antenna described in this application is described in detail.

[0047] Figure 6 This is a schematic diagram of the active VSWR of a high-frequency metasurface antenna at different scanning angles in the N78 band. Figure 6 In this model, different curves correspond to different scanning angles, such as different angles in the E-plane and H-plane directions (e.g., 30°, 45°, 60°, etc.). From Figure 6 As can be seen, the antenna's VSWR value fluctuates with changes in the scanning angle, indicating that the antenna's impedance matching varies at different scanning angles. Lower VSWR values ​​suggest the antenna is operating with good impedance matching, while higher VSWR values ​​may indicate higher reflection loss at certain angles. This data is of significant reference value for optimizing antenna performance and design, especially in multi-band communication and beam scanning applications.

[0048] Figure 7 This is a schematic diagram of the radiative characteristics of a high-frequency metasurface antenna in the 1.7-2.7 GHz frequency band. Figure 7 The radiation characteristics of the antenna at different frequencies are described, reflecting the antenna's radiation modes and efficiency in that frequency band. For example... Figure 7 As shown, the antenna's radiation directivity and intensity change with frequency, demonstrating its performance at different frequencies. By comparing the scatter plots at different frequencies, it can be seen whether the antenna's radiation performance in that frequency band meets the design requirements, especially for the radiation characteristics of high-frequency signals. The data provides crucial reference for optimizing antenna design and improving its operating efficiency.

[0049] Figure 8 This is a schematic diagram of a traditional cross dipole and a cross dipole structure with different FSS loaded on the dipole arms. Figure 8The three antenna structures shown are Ant.1, Ant.2, and Ant.3, illustrating the design of dipole arms and different FSS (Free Signal Support) structures. Ant.1 is a traditional crossed dipole antenna structure with standard dipole arms and no added FSS. Ant.2 adds FSS 1 to the dipole arms of the crossed dipole antenna. FSS 1 has a complex crossed shape designed to optimize frequency selectivity and improve signal transmission and radiation efficiency in specific frequency bands. Ant.3 adds FSS 2 to the dipole arms. FSS 2 has a simpler, square design, and its frequency response and radiation characteristics are further optimized by adjusting the geometry of the FSS. The transmission performance of the FSS is... Figure 9 As specified, it covers the N78 frequency band. Furthermore, Figure 8 The structure shown is rather simplified, lacking specific dimensions, material parameters, and actual test results, making it difficult to intuitively understand its performance in practical applications. Finally, the diagrams do not display the radiation modes or key performance indicators such as VSWR of these antennas at different frequency bands, making the actual effectiveness of the design less intuitive and clear.

[0050] Figure 9 yes Figure 6 A schematic diagram comparing the transmission coefficients of the dipole arms of three different cross-dipole structures. Figure 9 In the diagram, different curves represent the transmission coefficient variations of three different crossed dipole structures at different frequencies. By comparing these curves, we can see the differences in transmission coefficients across the frequency range, reflecting the impact of each structure on signal transmission. A higher transmission coefficient generally indicates better signal transmission performance, while a lower transmission coefficient indicates signal attenuation or loss. Figure 10 yes Figure 6 Schematic diagram of reflection coefficient and cross isolation of three types of cross dipole structures. Figure 10 The reflection coefficient curves show the reflection loss of each dipole structure at different frequencies. A lower reflection coefficient indicates better impedance matching of the antenna, enabling effective signal transmission. The cross-isolation curve reflects the degree of signal interference between different structures. Higher isolation means less interference between channels, which helps improve the overall system performance. By comparing these data, antenna design can be further optimized to improve signal quality and multi-band performance.

[0051] Figure 11 This is a schematic diagram of the electric field distribution of a conventional cross dipole antenna without an FSS shielding high-frequency metasurface antenna. Figure 12 This is a schematic diagram of the electric field distribution radiated by a cross-dipole transmission high-frequency metasurface antenna loaded with FSS. Figure 11In this system, the electric field distribution is relatively concentrated, mainly near the dipole, resulting in limited radiation effects, low radiation efficiency, and poor frequency selectivity. Compared to... Figure 11 ,exist Figure 12 In the process, after loading FSS, the electric field distribution becomes more uniform and widespread, which can effectively improve the radiation performance of the antenna. This indicates that the introduction of FSS helps to optimize the electric field distribution, making the transmission of high-frequency signals more efficient, improving radiation efficiency, and enhancing the frequency selectivity and beam control capability of the antenna.

[0052] Figure 13 This is a schematic diagram illustrating the simulation and test data of the reflection coefficient and cross-isolation of a low-frequency crossed dipole antenna in a low-profile common-aperture base station antenna. The reflection coefficient curve reflects the matching performance of the antenna at different frequencies. A lower reflection coefficient indicates good impedance matching, which can effectively reduce signal reflection loss. The cross-isolation curve shows the signal isolation between channels at different frequencies. Higher isolation indicates less interference between channels, ensuring independent operation of the antenna system and signal quality. Figure 13 The comparison between the simulation and test data shows that the antenna has good reflection performance and high signal isolation within the design frequency band, verifying the high efficiency and good performance of the antenna design in the low frequency band.

[0053] Figure 14 This is a schematic diagram of simulation data on the isolation between the low-frequency crossed dipole antenna and the high-frequency metasurface antenna element in a low-profile common-aperture base station antenna. Figure 14 The isolation curve reflects the mutual interference between the low-frequency crossed dipole antenna and the high-frequency metasurface antenna elements at different frequencies. Higher isolation indicates less interference between the two, effectively preventing cross-interference of signals. Figure 14 As can be seen, the antenna isolation remains at a high level as the frequency changes, ensuring that low-frequency and high-frequency signals can work independently in the common aperture structure, thereby improving the overall performance and frequency utilization efficiency of the antenna system.

[0054] Figure 15 This is a schematic diagram of the test data for the isolation between the low-frequency crossed dipole antenna and the high-frequency metasurface antenna element in a low-profile co-aperture base station antenna. Figure 15 In the diagram, the isolation curve reflects the mutual interference between the low-frequency crossed dipole antenna and the high-frequency metasurface antenna element at different frequencies under actual test conditions. Higher isolation indicates less signal interference between the two, effectively avoiding mutual influence between low-frequency and high-frequency signals. This can be further illustrated by... Figure 15 The test data shown demonstrates that the antenna maintains good isolation between different frequency bands, ensuring independent transmission of low-frequency and high-frequency signals, thereby improving the overall system performance and spectrum utilization efficiency.

[0055] Figure 16 This is a schematic diagram of the radiation direction of a dipole antenna at a frequency of 1.8 GHz; Figure 17 This is a schematic diagram of the radiation direction of a dipole antenna at a frequency of 2.2 GHz; Figure 18 This is a schematic diagram of the radiation direction of a dipole antenna at a frequency of 2.6 GHz. Figure 16 At 1.8 GHz, the dipole antenna exhibits a relatively uniform omnidirectional radiation pattern, and the antenna's radiation beam extends widely in the horizontal direction, demonstrating the antenna's radiation characteristics at lower frequencies, making it suitable for providing a wider signal coverage. Figure 17 At 2.2 GHz, the radiation pattern changes slightly, with the radiation beam starting to contract and focusing directly in front of the antenna. This indicates that the antenna's radiation directivity has become more concentrated, making it suitable for signal transmission in the mid-frequency band. Figure 18 At 2.6 GHz, as the frequency increases further, the antenna's radiation beam becomes more concentrated and the radiation directionality is stronger, indicating that the radiation in this frequency band has high directionality and is suitable for providing more accurate signal transmission.

[0056] Overall, as the frequency increases, the radiation mode of the dipole antenna gradually changes from a broad omnidirectional pattern to a more concentrated and directional pattern. This change helps to optimize the antenna's coverage and signal quality in different frequency bands.

[0057] Figure 19 This is a schematic diagram of the active VSWR simulation data of the central element in a high-frequency metasurface antenna array within a low-profile, common-aperture base station antenna. VSWR is an important parameter for measuring antenna impedance matching and reflects the antenna's radiation efficiency. Figure 19 In the simulation, different curves represent the variation of the VSWR value of the center element with the scanning angle at multiple frequencies, specifically including the performance at the front beam (Broadside), E-plane scanning angles (e.g., 30°, 45°, 60°), and H-plane scanning angles (e.g., 30°, 45°). The simulation data shows that the VSWR value fluctuates at different angles. A lower VSWR value indicates good impedance matching and high signal transmission efficiency in that frequency band; while a higher VSWR value indicates poor impedance matching at certain angles, resulting in signal reflection and loss. This data is of significant reference value for optimizing antenna design and improving its performance, especially in high-speed data communication applications such as 5G.

[0058] Figure 20 This is a schematic diagram of the active VSWR test data of the central element in a high-frequency metasurface antenna array within a low-profile, common-aperture base station antenna. Figure 19The simulation data differs from the actual test data; this data comes from real-world testing and reflects the antenna's performance in a real environment. By comparing the test data and the simulation data, Figure 20 The results show the degree of agreement between the actual VSWR values ​​of the center element and the simulation results at different frequencies. This test data further verifies the antenna's impedance matching performance and signal transmission efficiency. Lower VSWR values ​​in the test results indicate that the antenna can transmit signals effectively, while higher VSWR values ​​may indicate problems such as unstable frequency response or high reflection loss. These test data allow for adjustments to the antenna design to ensure optimal performance in practical applications.

[0059] Figure 21 This is a schematic diagram of active VSWR simulation data for edge elements in a high-frequency metasurface antenna array within a low-profile, common-aperture base station antenna. Compared to the center elements, edge elements are typically subject to more electromagnetic interference, which may cause their performance to differ across certain frequency ranges. Figure 21 Simulations were performed on the VSWR values ​​of edge elements at different frequencies, reflecting the impedance matching of the antenna at the edge locations. Observing the VSWR curves at different scanning angles reveals that the matching of edge elements is generally slightly worse than that of the center elements, mainly due to radiation non-uniformity caused by edge effects. Higher VSWR values ​​may indicate significant signal reflection or loss at specific frequencies. Optimizing the design of edge elements can improve their performance in high-frequency bands, reduce reflection loss, and increase the overall efficiency of the antenna array.

[0060] Figure 22 This is a schematic diagram of active VSWR test data for edge elements in a high-frequency metasurface antenna array within a low-profile, co-aperture base station antenna. These test data are based on results from real-world testing environments and are consistent with... Figure 21 By comparing the simulation data, more accurate data on antenna performance in practical applications can be provided. Figure 22 The VSWR values ​​of the edge elements at different frequencies are shown. Higher VSWR values ​​indicate poor impedance matching of the edge elements under actual operating conditions, which may lead to increased signal reflection or loss. By comparing simulation data and test data, the accuracy of the simulation model can be verified, and the antenna design can be further optimized based on the test data. The acquisition of actual test data provides practical evidence for improving the overall performance of the antenna, especially its applicability in multi-band and multi-angle beam scanning applications.

[0061] Figure 23 This is a schematic diagram of simulation data for E-plane beam scanning of a high-frequency metasurface antenna array in a low-profile, common-aperture base station antenna. Figure 23In the simulation, the radiation pattern of the E-plane beam changes significantly with the scanning angle, demonstrating the beam scanning effect at different angles. The simulation data shows the beam spread and focusing characteristics of the antenna array at different angles, indicating that the antenna array has good beam control performance in the E-plane direction and can achieve precise beam pointing control. This data helps optimize the design of the antenna array, ensuring accurate transmission and coverage of high-frequency signals.

[0062] Figure 24 This is a schematic diagram of E-plane beam scanning test data for a high-frequency metasurface antenna array in a low-profile, common-aperture base station antenna. Figure 23 Compared to the simulation data shown, Figure 24 The test data shown provides the beam scanning performance of the antenna array in the E-plane direction during actual operation. Figure 24 The curves in the figure show the radiation intensity and beamform at different scanning angles. The test results are consistent with the simulation data, verifying the beam scanning capability of the antenna array in practical applications. At different angles, the antenna beam broadens or focuses, ensuring multi-directional signal coverage. The test data further confirms the antenna array's beam control capability in the high-frequency band, improving overall communication performance and spectral efficiency.

[0063] Figure 25 This is a schematic diagram of simulation data for H-plane beam scanning of a high-frequency metasurface antenna array in a low-profile common-aperture base station antenna. Figure 25 In the simulation, the radiation intensity and morphology of the H-plane beam changed significantly with the change of the scanning angle. Simulation data shows that as the beam scanning angle is adjusted, the antenna's radiation pattern gradually shifts from a concentrated beam distribution to a wider coverage area, demonstrating excellent beam directivity control capability. This data provides a crucial reference for optimizing the coverage range and signal transmission performance of the H-plane beam.

[0064] Figure 26 This is a schematic diagram of E-plane beam scanning test data for a high-frequency metasurface antenna array in a low-profile, common-aperture base station antenna. Figure 25 The simulation data are similar. Figure 26 It provides beam scanning performance under actual test conditions. Figure 26 The test data shown reflects the beam scanning performance of the antenna array in the E-plane direction in practical applications. The radiation intensity and beam broadening at different scanning angles demonstrate that the antenna exhibits good beam control performance in the E-plane direction, capable of adapting to various signal transmission requirements. The test data further validates the simulation results, proving the actual beam scanning capability of the antenna array in the high-frequency band and ensuring effective signal coverage.

[0065] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A low-profile, common-aperture base station antenna, characterized in that, The antenna includes: A metasurface antenna element, wherein a low-frequency crossed dipole antenna is disposed on the upper surface of the metasurface antenna element, wherein, While the metasurface antenna element provides high-frequency signal radiation and performs wide-angle beam scanning, the low-frequency cross dipole antenna is used to provide low-frequency signal radiation and perform fixed-beam scanning to achieve multi-frequency signal coverage.

2. The antenna according to claim 1, characterized in that, The metasurface antenna element includes: Multiple stacked dielectric substrates, The plurality of stacked dielectric substrates include a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate, which are arranged in accordance with the propagation direction of the electromagnetic waves emitted by the low-frequency cross dipole antenna.

3. The antenna according to claim 2, characterized in that, A first mesh-like metal layer is disposed on the upper surface of the first dielectric substrate, and the low-frequency cross dipole antenna is disposed on the first mesh-like metal layer. The first mesh-like metal layer is used to guide and regulate the propagation of electromagnetic waves emitted by the low-frequency cross dipole antenna.

4. The antenna according to claim 3, characterized in that, A second mesh-like metal layer is disposed between the first dielectric substrate and the second dielectric substrate. The second mesh-like metal layer is used to couple electromagnetic waves guided and controlled by the first mesh-like metal layer.

5. The antenna according to claim 4, characterized in that, A metal ground layer is disposed between the second dielectric substrate and the third dielectric substrate, and the metal ground layer is used to reflect and shield the coupled electromagnetic waves.

6. The antenna according to claim 5, characterized in that, A feeder is provided at the bottom of the metal floor layer.

7. The antenna according to claim 4, characterized in that, The side length of the metal ring in the second mesh-like metal layer is half that of the first mesh-like metal layer.

8. The antenna according to claim 2, characterized in that, The third dielectric substrate has orthogonally arranged coupling grooves distributed alternately.

9. The antenna according to claim 8, characterized in that, The coupling groove can take any of the following geometric shapes: rectangle, circle, triangle and annulus.

10. The antenna according to claim 1, characterized in that, The low-frequency crossed dipole antenna includes: The radiating body is fixedly connected to the metasurface antenna unit via a 3D-printed bracket. An SMA connector is provided on the lower end face of the radiating body; The upper surface of the radiating body is provided with multiple identical dipole arms with embedded FSS structures. Microstrip feed lines are provided on the dipole arms. The dipole arms are connected to the outer conductor of the SMA connector, and the microstrip feed lines are connected to the inner conductor of the SMA connector.

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