Antenna unit, base station antenna, and communication device

Abstract

The present application relates to the technical field of antennas, and in particular to an antenna unit, a base station antenna, and a communication device. The antenna unit can be widely applied to various base station antennas, including active and passive antenna systems. The antenna unit comprises an excitation unit, a metasurface radiation structure and a reflecting surface, wherein the metasurface radiation structure and the reflecting surface are spaced apart oppositely, the excitation unit is used for exciting the metasurface radiation structure to radiate an electromagnetic signal, the reflecting surface is used for reflecting the signal radiated by the metasurface radiation structure, and the distance between the metasurface radiation structure and the reflecting surface varies in a first direction. The direction of a radiation beam can be changed to achieve deflection of the radiation beam.

Description

Antenna units, base station antennas and communication equipment

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410585383.7, filed on May 11, 2024, entitled "Antenna Element, Base Station Antenna and Communication Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of antenna technology, and in particular to an antenna element, a base station antenna, and a communication device. Background Technology

[0004] For coverage or network optimization purposes, base station antennas need to have a certain downtilt capability. Traditional technologies use mechanical devices to adjust the antenna's downtilt angle; however, when the adjustment angle exceeds the vertical half-power beamwidth, the horizontal beam coverage deteriorates and deforms, affecting sector coverage. Current antenna beam deflection control suffers from limited beam deflection capability. Summary of the Invention

[0005] This application provides an antenna element, a base station antenna, and a communication device that can change the direction of the radiated beam and achieve a more stable deflection of the radiated beam.

[0006] In a first aspect, this application provides an antenna element that can be widely used in various base station antenna configurations, including active and passive antenna systems. The antenna element includes an excitation element, a metasurface radiating structure, and a reflecting surface; the metasurface radiating structure and the reflecting surface are arranged at relative intervals; the excitation element is used to excite the metasurface radiating structure to radiate electromagnetic signals; the reflecting surface is used to reflect the signals radiated by the metasurface radiating structure; and the distance between the metasurface radiating structure and the reflecting surface varies along a first direction.

[0007] In the aforementioned antenna element, the excitation unit can excite the metasurface radiating structure to radiate electromagnetic signals. Since the distance between the metasurface radiating structure and the reflecting surface varies along the first direction, the electromagnetic signals generated by different regions of the metasurface radiating structure by the excitation unit will produce a phase difference when reflected by the reflecting surface. This can change the direction of the radiated beam, achieving beam deflection. When the first direction is the vertical radiation direction of the antenna element's radiated beam, the antenna's downtilt angle can be adjusted.

[0008] In some possible implementations, the excitation element can be one of a slot antenna, probe antenna, patch antenna, or dipole antenna. Its feeding method can be slot feeding, probe feeding, patch feeding, or dipole feeding.

[0009] In some possible implementations, the excitation unit is a dual-polarized radiator, such as ±45° dual-polarization.

[0010] In some possible implementations, the reflective surface includes a first reflective region and a second reflective region arranged along a first direction; the distance between the first reflective region and the metasurface radiating structure is greater than the distance between the second reflective region and the metasurface radiating structure. The reflective surface is divided into regions along the first direction, with different distances between different reflective regions and the metasurface radiating structure. The electromagnetic signal radiation phase generated by the metasurface radiating structure corresponding to different reflective regions is different, thus achieving beam deflection.

[0011] In some possible implementations, both the first and second reflecting regions are planar, and at least one of the first and second reflecting regions is set at an angle to the first direction. The tilting of at least one of the first and second reflecting regions can cause the electromagnetic signal radiation phase generated by the metasurface radiation structure to differ according to the different reflecting regions, thereby achieving beam deflection.

[0012] In some possible implementations, both the first and second reflecting regions are set at an angle to the first direction, and the first and second reflecting regions are coplanar. The reflecting surface is a continuous plane and is set at an angle to the first direction, in which case the reflecting surface is tilted relative to the metasurface radiation structure.

[0013] In some possible implementations, both the first and second reflecting regions are planar and parallel to each other, and the reflecting surface includes a transition region connecting the first and second reflecting regions. In this implementation, the different reflecting regions can all be parallel to a first direction.

[0014] In some possible implementations, the first reflecting region includes a base surface, and the second reflecting region includes a ridge surface. The ridge surface protrudes from the base surface of the metasurface radiating structure, and there may be one or more ridge surfaces. The distance between the ridge surface and the metasurface radiating structure is smaller than the distance between the base surface and the metasurface radiating structure, so that the electromagnetic signal radiation phase generated by the metasurface radiating structure corresponding to different reflecting regions is different, thereby achieving deflection of the radiation beam.

[0015] In some possible implementations, there are multiple ridges, which are spaced apart along a first direction. The ridges can be planar, curved, or inclined, extending perpendicular to the first direction. The shape of the cross-section of the second reflective region perpendicular to the extension direction can be rectangular, arched, triangular, or other regular or irregular shapes.

[0016] In some possible implementations, the excitation unit and the second reflection region are positioned opposite each other along the alignment direction of the metasurface radiating structure and the reflecting surface. The distance between the second reflection region and the metasurface radiating structure is smaller than the distance between the first reflection region and the metasurface radiating structure, which can optimize the radiation effect of the excitation unit on the metasurface radiating structure to radiate electromagnetic waves.

[0017] In some possible implementations, the metasurface radiating structure includes a dielectric substrate and a plurality of metasurface units fixed to the dielectric substrate. Along a first direction, the plurality of metasurface units includes a subset of metasurface units and a subset of metasurface units, with the distance between the subset of metasurface units and the reflecting surface being greater than the distance between the subset of metasurface units and the reflecting surface. In this embodiment, the structure of the metasurface radiating structure is changed, causing a structural variation along the first direction, thereby changing the distance between the metasurface radiating structure and the reflecting surface along the first direction.

[0018] In some possible implementations, a portion of the metasurface units and another portion of the metasurface units are disposed on the same surface of the dielectric substrate, with the dielectric substrate positioned at an angle to the first direction. The metasurface radiating structure can be a continuous plate-like structure positioned at an angle to the first direction, in which case the metasurface radiating structure is tilted relative to the reflecting surface.

[0019] In some possible implementations, the reflective surface is set at an angle to the first direction, and the angle between the dielectric substrate and the first direction is not equal to the angle between the reflective surface and the first direction. In this case, both the reflective surface and the metasurface radiation structure are tilted, and the different tilt angles of the two can further expand the beamforming capability of the vertical plane of the radiation beam, and achieve a larger beam deflection angle.

[0020] In some possible implementations, a portion of the metasurface units are disposed on the surface of the dielectric substrate facing away from the reflective surface, while another portion of the metasurface units are disposed on the surface of the dielectric substrate facing the reflective surface. The plurality of metasurface units facing the reflective surface form a second radiation region, and the plurality of metasurface units facing away from the reflective surface form a first radiation region.

[0021] In some possible implementations, the reflecting surface is set at an angle to the first direction, and the angle between the metasurface radiating structure and the first direction is not equal to the angle between the reflecting surface and the first direction.

[0022] In some possible implementations, the metasurface radiating structure includes a dielectric substrate and multiple metasurface units fixed to the dielectric substrate, with the excitation unit fixed to the dielectric substrate and needing to avoid the metasurface units. Alternatively, the excitation unit can be positioned between the reflecting surface and the metasurface radiating structure, and the excitation unit can be specifically fixed to the reflecting surface by a support member.

[0023] In some possible implementations, at least one excitation unit is provided on each of the two surfaces of the dielectric substrate.

[0024] In some possible implementations, the excitation unit is offset from the center of the metasurface radiation structure along the first direction, which can selectively optimize the sidelobe gain of the radiation beam and improve the directivity coefficient.

[0025] Secondly, this application provides a base station antenna, including a filtering circuit and any of the antenna elements provided in the first aspect, wherein the filtering circuit is electrically connected to the antenna element. The antenna element can achieve more stable radiation beam deflection, and through the filtering process of the filtering circuit, interference from other frequency band signals to the target frequency band signal can be removed. The filtering circuit, for example, can have highly selective bandpass filtering characteristics. The filtering circuit can be integrated into the antenna circuit or can be a separately designed circuit with filtering function. The filtering circuit can be, for example, a filter. The base station antenna using the above-described antenna element has better beam deflection adjustment capability, and the sidelobe gain of the antenna radiation is improved.

[0026] In some possible implementations, multiple antenna elements are used, arranged in an array to form an array antenna, with each element electrically connected to a filter circuit. In this scheme, the metasurface radiating structure possesses electromagnetic bandgap characteristics specific to surface waves, suppressing surface wave propagation within the antenna's operating frequency band. This suppresses antenna mutual coupling caused by surface wave propagation, achieving self-decoupling of the antenna. Therefore, after arranging multiple antenna elements in an array to form an array antenna, the isolation between antenna elements in the antenna array is low, the radiation pattern distortion is small, and the wireless network performance is improved.

[0027] Thirdly, this application provides a communication device including at least two base station antennas as described in the second aspect above. Using this base station antenna can improve the antenna performance of the communication device. Attached Figure Description

[0028] Figure 1 is a schematic diagram of the architecture of a communication device provided in an embodiment of this application;

[0029] Figure 2 is a schematic diagram of a base station provided in an embodiment of this application;

[0030] Figure 3 shows a partial structure of the internal frame of a base station antenna provided in an embodiment of this application;

[0031] Figure 4a is a schematic diagram of an antenna unit provided in an embodiment of this application;

[0032] Figure 4b is an exploded view of an antenna element provided in an embodiment of this application;

[0033] Figure 5a is a schematic diagram of the metasurface radiation structure of an antenna element provided in an embodiment of this application;

[0034] Figure 5b is a magnified view of some structural details of a metasurface radiating structure of an antenna element provided in an embodiment of this application;

[0035] Figure 5c is a schematic diagram of an antenna element excitation unit disposed on a metasurface radiating structure according to an embodiment of this application;

[0036] Figure 6 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0037] Figure 7 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0038] Figure 8 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0039] Figure 9 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0040] Figure 10 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0041] Figure 11 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0042] Figure 12a is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0043] Figure 12b is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0044] Figure 12c is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0045] Figure 13 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0046] Figure 14 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0047] Figure 15a is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0048] Figure 15b is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0049] Figure 15c is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0050] Figure 16a is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0051] Figure 16b is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0052] Figure 17 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0053] Figure 18a is a schematic diagram of the metasurface radiation structure of an antenna element provided in an embodiment of this application;

[0054] Figure 18b is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0055] Figure 19 is a schematic diagram of the metasurface radiation structure of an antenna element provided in an embodiment of this application;

[0056] Figure 20a is a schematic diagram of the metasurface radiation structure of an antenna element provided in an embodiment of this application;

[0057] Figure 20b is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application;

[0058] Figure 21 is a partial cross-sectional structural diagram of an antenna element provided in an embodiment of this application.

[0059] Reference numerals: 1000-Base station; 2000-Terminal; 100-Base station antenna; 200-Support frame; 300-Grounding device; 400-Baseband processing unit; 500-Connecting wire; 600-Adjustment bracket; 10-Antenna array; 20-Antenna connector; 30-Antenna radome; 40-Feed network; 401-Phase shifter; 402-Power divider; 403-Filter; 1-Excitation unit; 2-Metasurface radiating structure; 21, 21a, 21b-Dielectric substrate; 22, 22a, 22b-Metasurface unit; 221-Edge unit; 222-Internal unit; 3-Reflection structure; 31-First part; 32-Second part; 33-Connecting part; 34-Planar part; 35-Ridge part; 4-Metal back cavity; 41-Metal base plate; 42-Metal frame; 5-Supporting component. Detailed Implementation

[0060] In the field of antenna technology, electrical downtilt is a method to adjust the beam tilt angle by pre-setting a certain phase difference within and between subarrays. It has advantages such as uniform coverage, fast adjustment speed, and flexibility. Currently, the main way to achieve beam deflection in beam-controllable antennas is by shifting the main feed point and setting a phase shift network, which suffers from large dispersion and limited beam deflection capability. In addition, as the electrical downtilt angle increases, the sidelobes of the antenna's radiating vertical plane will rise rapidly under the influence of the array factor, thereby deteriorating the overall performance of the antenna, especially for large-aperture elements in the vertical direction, where the impact is particularly critical.

[0061] Based on this, embodiments of this application provide an antenna unit, a base station antenna, and a communication device. The antenna unit can deflect the radiated beam and optimize antenna performance.

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0063] This application provides a communication device, which includes, but is not limited to, base stations, radars, switches, routers, gateways, servers, network interface cards, wireless access points, modems, optical transceivers, fiber optic transceivers, mobile phones, tablets, laptops, and wearable devices (such as smart glasses, smart bracelets, smartwatches, and wireless headphones). This communication device has an antenna system. The following description uses a base station as an example.

[0064] Figure 1 illustrates a schematic diagram of the communication principle architecture of a communication device. Base station 1000 is used for cell coverage of wireless signals to enable communication between terminal 2000 and the wireless network. Base station 1000 can also be called an access network device or access node. It can be located in a base station subsystem (BBS), a UMTS terrestrial radio access network (UTRAN), or an evolved universal terrestrial radio access network (E-UTRAN) to provide cell coverage of signals for communication between the terminal device and the wireless network. Specifically, base station 1000 can be a base transceiver station (BTS) in a Global System for Mobile Communication (GSM) or Code Division Multiple Access (CDMA) system, a Node B (NB) in a Wideband Code Division Multiple Access (WCDMA) system, an evolved Node B (eNB or eNodeB) in a Long Term Evolution (LTE) system, a transmission reception point (TRP), a next-generation base station (gNB) in a 5G mobile communication system, a next-generation base station in a 6th generation (6G) mobile communication system, an access network device or module of an access network device in an open RAN (ORAN) system, a base station in a future mobile communication system, or an access node in a WiFi system, etc. A base station can be a central unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU), as described below. In the ORAN system, a CU can also be called an O-CU, a DU can be called an open (O)-DU, a CU-CP can be called an O-CU-CP, a CU-UP can be called an O-CUP-UP, and a RU can be called an O-RU.The base station 1000 in this application can be a macro base station, micro base station, or indoor station, a relay node or donor node, or a wireless controller in a cloud radio access network (CRAN) scenario. Alternatively, the base station 1000 can also be a server, in-vehicle equipment, wearable devices, or g-nodes (gNodeB or gNB) in new radio (NR) systems, or access network equipment in future evolved networks. For example, the base station in vehicle-to-everything (V2X) technology can be a roadside unit (RSU). Multiple base stations 1000 in the communication system can be of the same type or different types. The base station 1000 can communicate with the terminal 2000 or through a relay station. The terminal 2000 can communicate with multiple base stations 1000 in different access technologies. In some embodiments, the communication device may include at least two base stations 1000.

[0065] Base station 1000 is equipped with base station antenna 100 (belonging to an antenna system) to transmit signals in space. Figure 2 shows a schematic diagram of an application scenario of the base station antenna 100 equipped with base station 1000 as shown in Figure 1. Base station antenna 100 may include antenna array 10, antenna connector 20, and radome 30. Antenna array 10, antenna connector 20, and radome 30 are components of base station antenna 100. Base station antenna 100 may also include a feed network and reflection structure, which will be described below. Antenna array 10 is fixed to support frame 200 such as a pole or tower by radome 30 to facilitate signal reception or transmission by antenna array 10. Radome 30 has good electromagnetic wave penetration characteristics in terms of electrical performance and can withstand the influence of harsh external environments in terms of mechanical performance, thus protecting the antenna system from external environmental influences. Support frame 200 is fixed to the ground at a certain height above the ground, and radome 30 is fixed to support frame 200, which can meet the radiation distance requirements of base station antenna 100. The radome 30 is detachably fixed to the support frame 200 via an adjusting bracket 600 to facilitate signal reception or transmission by the antenna array 10. The orientation of the antenna array 10 can be adjusted via the adjusting bracket 600 along a direction perpendicular to the height of the support frame 200.

[0066] The base station 1000 may further include a baseband processing unit 400. The antenna array 10 is connected to the baseband processing unit 400 via an antenna connector 20 located outside the radome 30. Specifically, the antenna connector 20 and the baseband processing unit 400 are connected via a connecting wire 500. In some embodiments, the baseband processing unit 400 may also be referred to as a baseband unit (BBU). A grounding device 300 is provided between the baseband processing unit 400 and the connecting wire 500. The grounding device 300 generally includes a grounding electrode buried underground. A seal may be provided at the connection point between the connector 20 of the base station antenna 100 and the connecting wire 500, and a seal may also be provided at the connection point between the grounding device 300 and the connecting wire 500. The seal may specifically include at least one of insulating sealing tape and polyvinyl chloride (PVC) insulating tape. Of course, the seal may also have other structures and is not limited to the form of tape.

[0067] Antenna array 10 is used for radiating and receiving antenna signals. Antenna array 10 may include several antenna elements arranged in a certain pattern, each antenna element capable of radiating and receiving electromagnetic waves. Each antenna element may include an antenna vibrator. In antenna array 10, different antenna elements may operate in the same or different frequency bands. Each antenna element may include a connected radiating structure and a feeding structure. The radiating structure is used for signal radiation and reception; the feeding structure connects the radiating structure and the feeding network to transmit electrical signals transmitted from the feeding network to the radiating structure and vice versa.

[0068] [Corrected according to Rule 91, May 14, 2025] The antenna element may also include a reflective structure, which may also be called a base plate, antenna panel, or reflective surface, etc. The reflective structure may be made of metal, for example. The radiating element may be mounted on the surface of one side of the reflective structure. When the radiating element receives the antenna signal, the reflective structure can reflect the antenna signal to the receiving point, thereby achieving directional reception; when the radiating element transmits the antenna signal, the reflective structure can achieve directional transmission of the antenna signal. The reflective structure can enhance the antenna signal receiving or transmitting capability of the radiating element, and can also block and shield the interference of other signals from the back of the reflective structure (the back refers to the side of the reflective structure facing away from the radiating element) on the antenna signal, thereby improving the antenna gain.

[0069] Figure 3 illustrates a portion of the internal framework structure of the base station 1000 in Figure 2. As shown in Figure 3, the antenna array 10 of the base station 1000 is connected to the feed network 40. The feed network 40 can achieve different radiation beam directions through a transmission mechanism, or be connected to a calibration network to obtain the calibration signals required by the base station 1000. The feed network 40 can feed signals to the antenna array 10 with a certain amplitude and phase, or transmit the received signals to the baseband processing unit 400 with a certain amplitude and phase.

[0070] Schematic, the feed network 40 may include a phase shifter 401, used to change the maximum direction of antenna signal radiation. The feed network 40 may also include modules for extending performance, such as a power divider 402. The power divider 402 is used to combine multiple signals into a single signal for transmission through the antenna array 10; or, the power divider 402 may divide a single signal into multiple signals, for example, dividing the signal received by the antenna array 10 into multiple paths according to different frequencies for transmission to the baseband processing unit 400 for processing. The feed network 40 may also include a filter 403 for filtering out interference signals. In some embodiments, the feed network 40 may also include a combiner. In some embodiments, the feed network 40 may also include any form of transmission line, such as a coaxial line, stripline, microstrip line, etc.

[0071] The structure of base station 1000 shown in Figures 2 and 3 is merely an example. In fact, the structure of base station 1000 in this application embodiment can be flexibly designed according to product requirements and is not limited to what is described above.

[0072] Figure 4a is a schematic diagram of the structure of one antenna element of a base station antenna 100 provided in an embodiment of this application, and Figure 4b is an exploded view of the antenna element. The base station antenna 100 may include one or more antenna elements shown in Figures 4a and 4b. The antenna elements provided in this embodiment of the application can be widely used in various base station antenna configurations, including active and passive antenna systems.

[0073] Referring to Figures 4a and 4b, the antenna element includes an excitation element 1, a metasurface radiating structure 2, a reflecting structure 3, and a metal back cavity 4. The reflecting structure 3 has a reflecting surface F. Both the metasurface radiating structure 2 and the reflecting structure 3 are fixed to the metal back cavity 4. There is a certain gap between the metasurface radiating structure 2 and the reflecting structure 3, such that the reflecting surfaces F of the metasurface radiating structure 2 and the reflecting structure 3 are relatively spaced apart, with the reflecting surface F facing the metasurface radiating structure 2. Exemplarily, the antenna element has a shape similar to a cuboid. For ease of understanding, a three-dimensional coordinate system is established based on the structure of the antenna element. The X direction is the width direction of the antenna element, the Y direction is the length direction of the antenna element, and the Z direction is the height direction of the antenna element. When the antenna element is installed on the mast of the base station 1000, the Y direction is parallel to the vertical direction of radiation from the base station antenna 100, and the X direction is parallel to the horizontal direction of radiation from the base station antenna 100. The X, Y, and Z directions are mutually perpendicular. When the antenna element is applied to the base station antenna 100, the X direction is approximately parallel to the ground. In the antenna element provided in this embodiment, the dimension of the antenna element along the Y direction is larger than its dimension along the X direction. The vertical beamwidth of the base station antenna 100 can be adjusted by adjusting the dimension of the antenna element along the Y direction. Alternatively, the vertical beamwidth can be reduced by increasing the dimension of the antenna element along the Y direction, thereby improving the antenna gain and efficiency.

[0074] In this embodiment, the excitation unit 1 is exemplarily an orthogonally polarized feed patch, meaning the polarization of the feed patch can be dual-polarized. For example, the polarization of the feed patch can be ±45°, or it can be 0° and 90°. This application does not limit the specific polarization of the feed patch. The excitation unit 1 is used to excite the metasurface radiation structure 2 to radiate signals via near-field coupling, and the reflecting surface F of the reflecting structure 3 is used to reflect the signals radiated by the metasurface radiation structure 2. Specifically, the excitation unit 1 can be integrated into the metasurface radiation structure 2. Of course, the excitation unit 1 can be a slit, probe, dipole, patch, or other structural form. Correspondingly, the feeding method of the excitation unit 1 can be slit feeding, probe feeding, patch feeding, dipole feeding, etc., and this application does not limit this.

[0075] The metal back cavity 4 may include a metal base plate 41 and a metal frame 42. The metal base plate 41 is, for example, rectangular, and the metal frame 42 surrounds the edge of the metal base plate 41. The metal base plate 41 and the metal frame 42 are assembled to form an open box-like structure. An open receiving cavity Q can be formed between the interior of the metal base plate 41 and the inner wall of the metal frame 42. The metal base plate 41 and the metal frame 42 can be manufactured as an integral metal back cavity 4 using a profile processing or other integrated process. Alternatively, the metal base plate 41 and the metal frame 42 can be assembled from separate profiles to form the metal back cavity 4. The reflective structure 3 can be installed inside the metal back cavity 4 and close to the metal base plate 41, i.e., the reflective structure 3 is disposed within the receiving cavity Q of the metal back cavity 4. The metasurface radiation structure 2 can be installed on the side of the metal frame 42 facing away from the metal base plate 41, thus creating a certain distance between the reflective surfaces F of the metasurface radiation structure 2 and the reflective structure 3.

[0076] It should be understood that in this application, the surfaces of the metal base plate 41 and the metal frame 42 of the metal back cavity 4 can both be closed surfaces, thus forming a closed cavity between the metasurface radiation structure 2 and the metal back cavity 4. Alternatively, at least one of the metal base plate 41 and the metal frame 42 of the metal back cavity 4 can be a hollow structure or include holes, or the metal frame 42 can be only disposed at the apex corners of the metal base plate 41, making the metal back cavity 4 a semi-open or fully open frame structure, which is beneficial for reducing the weight of the base station. The metal base plate 41 and the metal frame 42 are connected and electrically conductive, meaning that the metal base plate 41 and the metal frame 42 are in physical contact and can achieve a circuit connection, and electrical signals can be transmitted between them through physical lines. Alternatively, the metal base plate 41 and the metal frame 42 are not directly connected structurally, but transmit electrical signals through coupling. The metal back cavity 4 formed by the metal base plate 41 and the metal frame 42 has a conductive function.

[0077] As shown in Figure 5a, the metasurface radiating structure 2 in this embodiment may specifically include a dielectric substrate 21 and a plurality of metasurface units 22 formed on the dielectric substrate 21, with a gap j between any two adjacent metasurface units 22. Figure 5b illustrates a partial enlarged view of the structural details of the metasurface radiating structure 2. Exemplarily, the plurality of metasurface units 22 may be disposed on one surface of the dielectric substrate 21 in the same layer, with each metasurface unit 22 protruding from the surface of the dielectric substrate 21. The shapes of the metasurface units 22 may be the same or different, and the plurality of metasurface units 22 may be arranged regularly or irregularly as required. The dielectric substrate 21 may be an insulating material, and the plurality of metasurface units 22 are distributed within the surface range of the dielectric substrate 21. Referring to the shape of the dielectric substrate 21, in some implementations, all gaps j are interconnected, and the plurality of gaps j are distributed in a cross-network pattern, specifically with the plurality of metasurface units 22 extending in a ±45° direction, and the +45° gaps j intersecting perpendicularly with the -45° gaps j.

[0078] To accommodate the structure and distribution of the gap j, the multiple metasurface units 22 may specifically include edge units 221 and internal units 222. For distinction, the internal units 222 are shown in shaded areas. Both edge units 221 and internal units 222 can be multiple, with the edge units 221 enclosing the internal units 222. The metasurface units 22 of each edge unit 221 are arranged in a triangular-like structure, and the shape and size of each edge region S1 can be consistent, for example. The metasurface units 22 of each internal unit 222 are arranged in a rhomboid-like structure, and the shape and size of each internal unit 222 can be consistent. Of course, the multiple metasurface units 22 and the gap j of the metasurface radiation structure 2 can also have other distribution patterns, such as a cross shape or a grid shape, or an irregular shape.

[0079] Of course, the shape of gap j can be designed as needed; for example, all gaps j can be straight. The size of gap j can be designed as needed; for example, all gaps j can have the same size. This size can include at least one of shape size and position size, wherein the shape size can include at least one of width, length, depth, etc., and the position size can include at least one of the included angle between adjacent intersecting gaps, the spacing between parallel gaps, etc.

[0080] The metasurface radiating structure 2 can be a purely passive device. In this embodiment, the metasurface radiating structure 2 is used as the radiating structure that generates electromagnetic waves, which reduces the size of the antenna element along the Z-direction, resulting in a thinner antenna element that facilitates the implementation of a ground-profile antenna. In practical applications, the antenna operating frequency and bandwidth can be adjusted by designing the structure of the metasurface element 22 and the gap j between the metasurface elements 22, allowing the antenna element to operate in multi-mode or dual-mode, thereby expanding the antenna bandwidth. The metasurface radiating structure 2 possesses electromagnetic bandgap characteristics specific to surface waves, which can suppress surface wave propagation within the antenna's operating frequency band, thereby suppressing antenna mutual coupling caused by surface wave propagation and achieving antenna self-decoupling.

[0081] It should be understood that the relative positions of the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 mean that, along the Z-direction, the metasurface radiating structure 2 can be at least partially projected onto the reflecting surface F of the reflecting structure 3. This allows the electromagnetic waves generated by the metasurface radiating structure 2 after being excited by the excitation unit 1 to be at least partially reflected by the reflecting surface F of the reflecting structure 3, thereby achieving the antenna radiation function. The relative positions of the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 encompass both their structural positional relationship and the relationship for achieving the antenna function.

[0082] Based on the above-described structure of the metasurface radiating structure 2, when the excitation unit 1 is integrated into the metasurface radiating structure 2, it can be specifically arranged on the dielectric substrate 21 of the metasurface radiating structure 2. For example, as shown in FIG5c, when the excitation unit 1 is arranged on the surface of the dielectric substrate 21 having the metasurface unit 22, the excitation unit 1 should avoid the metasurface unit 22. Specifically, referring to a predetermined position of the excitation unit 1, the metasurface unit 22 at that position can be removed, and the excitation unit 1 can be placed at that position. Referring to FIG5b and FIG5c together, compared to FIG5b, the region W where the excitation unit 1 is located in FIG5c does not have a metasurface unit 22.

[0083] When integrating the excitation unit 1 onto the metasurface radiating structure 2, the bonding method between the excitation unit 1 and the dielectric substrate 21 can be similar to the bonding method between the metasurface unit 22 and the dielectric substrate 21. Since the metasurface unit 22 is manufactured using printed circuit board (PCB) technology, the excitation unit 1 can also be formed on the dielectric substrate 21 using a printed circuit board method. Alternatively, the radiating metasurface structure 22 can also be manufactured using other suitable processes.

[0084] It should be understood that the shape of the excitation unit 1 and its relative position to the metasurface unit 22 shown in Figure 5c are merely illustrative examples. In specific implementations, the structure and shape of the excitation unit 1 may be different, and the distribution of the region W used to set the excitation unit 1 and the metasurface unit 22 can be adaptively adjusted according to the excitation unit 1, as long as there is a distance between the excitation unit 1 and the metasurface unit 22.

[0085] When the number of excitation units 1 is greater than or equal to two, at least one excitation unit 1 can be respectively disposed on each of the two surfaces of the dielectric substrate 21. After the excitation unit 1 receives the feed signal transmitted by the feed network, it can excite multiple metasurface units 22 of the metasurface radiating structure 2 to radiate electromagnetic waves. The metal back cavity 4 can provide short-circuit boundary conditions for the metasurface radiating structure 2 to constrain the operating mode of the antenna unit.

[0086] In the antenna unit provided in this embodiment, the distance between the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 is set to vary along a first direction. This changes the phase of the radiated signal generated after the metasurface radiating structure 2 is excited, causing it to be reflected by different reflecting surfaces F. This alters the antenna radiation pattern, deflects the radiation beam direction, and optimizes the antenna radiation effect. When the antenna unit is applied to a base station antenna 100, the Y direction can be set as the vertical direction of the antenna's radiation, allowing adjustment of the antenna's downtilt angle.

[0087] Figure 6 illustrates a partial cross-sectional view of the antenna element, with the cross-section plane parallel to the planes containing the Y and Z directions and perpendicular to the X direction. Exemplarily, the metasurface radiating structure 2 is parallel to the metal base plate 41 of the metal back cavity 4, and the reflecting structure 3 is disposed within the receiving cavity Q of the metal back cavity 4, with the reflecting surface F of the reflecting structure 3 forming an angle θ with the metal base plate 41 of the metal back cavity 4. The size of the angle θ is related to the structure of the reflecting structure 3 and the metal back cavity 4; θ can be exemplarily chosen to be less than or equal to 45°, such as 1°, 2°, 10°, 25°, 45°, etc. It should be understood that the selection of the angle θ needs to be implemented based on satisfying the radiation function of the antenna element, and in some cases, the shape and volume of the antenna element also need to be considered. Specifically, the reflective structure 3 can be a plate-like structure of uniform thickness. The surface of the reflective structure 3 facing the metasurface radiating structure 2 is the reflective surface F, which is set at an angle θ with the metal base plate 41. The surface of the reflective structure 3 away from the metasurface radiating structure 2 is parallel to the reflective surface F and also set at an angle θ with the metal base plate 41. A wedge-shaped cavity is formed between the reflective structure 3 and the metal base plate 41. Along the Y direction, one end of the reflective structure 3 abuts against the metal base plate 41, and the other end abuts against the metal frame 42, so that the reflective surface F of the reflective structure 3 is set at an angle θ with the metal base plate 41. Thus, along the Y direction, the distance between the metasurface radiating structure 2 and the reflective surface F varies along the Y direction, which can be considered as the first direction. When the horizontal direction of the antenna element radiation is parallel to the X direction, and the vertical direction of the antenna element radiation is parallel to the Y direction, the angle of the antenna element reflective surface F facing the ground changes, which can adjust the downtilt angle of the base station antenna 100 radiation. The electromagnetic signals generated by the excitation unit 1 at different positions of the metasurface radiating structure 2 reach the reflecting surface F of the reflecting structure 3 at different distances, resulting in different phases of the electromagnetic signals emitted by the antenna unit, thus deflecting the antenna's radiation beam. In this embodiment, the reflecting surface F of the reflecting structure 3 is tilted relative to the metasurface radiating structure 2 along the Y direction, and the distance between the reflecting surface F and the metasurface radiating structure 2 varies approximately uniformly along the Y direction. Therefore, the phase change of the electromagnetic signals generated by the excitation unit 1 after being reflected at different positions of the reflecting surface F can exhibit a uniform gradient change, achieving stable radiation beam deflection.

[0088] In some embodiments, along the Y direction, the excitation unit 1 is located at the center of the metasurface radiation structure 2, the reflection structure 3 is tilted along the Y direction, and the metasurface radiation structure 2 is horizontally arranged relative to the Y direction.

[0089] Taking the antenna element shown in Figure 6 as an example, performance simulation of the antenna element is performed. Using the Y-direction as a reference, the radiation direction of the antenna element is compared in both horizontal and tilted states of the reflecting surface F of the reflecting structure 3. At the same operating frequency, the antenna element with the tilted reflecting structure 3 achieves stable beam deflection compared to the antenna element with the horizontal reflecting structure 3. As the angle between the reflecting surface F of the reflecting structure 3 and the Y-direction is gradually increased from near 0°, the direction of the main lobe of the antenna element's radiated beam adjusts accordingly and remains stable within a certain bandwidth. In other words, by tilting the reflecting surface F of the reflecting structure 3 relative to the Y-direction, the angle between the main lobe direction and the horizontal plane can be adjusted and maintained stable within a certain bandwidth, thereby achieving stable beam deflection.

[0090] As shown in Figure 7, an antenna element differs from the one shown in Figure 6 in that the metal back cavity 4 only includes a metal frame 42, eliminating the need for a metal base plate 41. The edge of the reflective structure 3 is fixedly connected to the inner wall of the metal frame 42. The reflective structure 3, the metal frame 42, and the metasurface radiating structure 2 together form a cavity. With the plane of the metasurface radiating structure 2 parallel to the X and Y directions as a reference, the reflecting surface F of the reflective structure 3 is inclined relative to the metasurface radiating structure 2 along the Y direction, and the distance between the reflecting surface F and the metasurface radiating structure 2 varies along the Y direction.

[0091] For ease of description, the following embodiments will be illustrated by the example of a metal back cavity 4 including a metal base plate 41 and a metal frame 42.

[0092] In some embodiments, an antenna element may contain multiple excitation elements 1. As shown in Figure 8, two excitation elements 1 are arranged along the Y direction. The other structures of the antenna element are similar to those in Figure 6 and will not be described again here. By designing multiple excitation elements 1, the excitation area can be increased, ensuring the excitation effect of the excitation elements 1.

[0093] Compared with conventional antennas, the antenna element shown in Figure 8, under the same condition of having two excitation elements 1, exhibits greater radiation sidelobes. With a fixed main lobe deflection angle, the tilted reflector surface F of the reflector structure 3 can compensate for the phase difference between the excitation elements 1, making the feed network structure design more flexible.

[0094] Comparing the antenna element shown in Figure 8 with that shown in Figure 6, when the antenna element has two or more excitation elements 1, and with the structure where the distance between the reflective surfaces F of the metasurface radiating structure 2 and the reflective structure 3 varies along the Y direction, the direction of the radiated beam can be adjusted and the sub-board optimized. Based on the effect of antenna radiated beam deflection, the feed network can be simplified, the overall efficiency of the antenna system can be improved, and lower line loss can be achieved.

[0095] In other implementations, taking an excitation unit 1 as an example, the excitation unit 1 can be offset from the center of the metasurface radiating structure 2 along the Y direction. As shown in Figure 9, compared to the antenna unit shown in Figure 6, the excitation unit 1 is offset to one side relative to the center of the metasurface radiating structure 2 along the Y direction. Figure 9 shows a design offset in the negative Y direction; however, it can also be offset in the positive Y direction. This structural design further alters the phase of the electromagnetic signal generated by the excitation unit 1 exciting the metasurface radiating structure 2, thereby achieving larger angle beam deflection and sidelobe optimization control.

[0096] In some implementations, taking an excitation unit 1 as an example, the excitation unit 1 can be positioned between the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3. As shown in Figure 10, compared to the antenna unit shown in Figure 6, the excitation unit 1 is located between the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3. Specifically, a support member 5 can be added to fix the excitation unit 1 to the reflecting structure 3. The support member 5 protrudes from the reflecting surface F of the reflecting structure 3, and the excitation unit 1 is fixed to the support member 5. Here, the support member 5 can be a balun or similar structure.

[0097] It should be understood that, compared with traditional antenna elements, the antenna element provided by the above implementation method has the reflective surface F of the reflective structure 3 set at an angle to the Y direction. In essence, it changes the distance between the reflective surface F at different positions and the metasurface radiation structure 2, thereby changing the phase difference generated by the electromagnetic signal generated by the excitation unit 1 on the metasurface radiation structure 2 at different positions of the reflective surface F, thereby changing the direction of antenna radiation and realizing beam deflection.

[0098] In the antenna element provided in this application, by varying the distance between different positions of the reflecting surface F of the reflecting structure 3 and the metasurface radiating structure 2 along the Y direction, the direction of antenna radiation can be changed, thereby achieving beam deflection. Based on this, embodiments of this application also provide other implementations of the antenna element, and the following will exemplarily describe antenna elements with different structures through different embodiments.

[0099] Figure 11 shows a cross-sectional view of an antenna element. The reflective structure 3 is wedge-shaped and has a reflective surface F facing the metasurface radiating structure 2. The reflective surface F is set at an angle θ with the Y direction. The size of the angle θ is related to the shape of the reflective structure 3, and can be exemplarily selected as 1°, 2°, 10°, 25°, 45°, etc., less than or equal to 45°. The surface of the reflective structure 3 facing away from the reflective surface F is in contact with the metal base plate 41. Compared with the antenna element shown in Figure 6, the reflective structure 3 in Figure 11 has a different structural form. The reflective structure 3 is in full-surface contact with the metal base plate 41 without any cavity. It can be considered that the reflective surface F of the reflective structure 3 and the metal base plate 41 are a solid structure. The structural connection between the reflective structure 3 and the metal back cavity 4 is more stable, which can improve the reliability of the antenna element.

[0100] Figure 12a shows a cross-sectional view of an antenna element. The reflecting surface F of the reflecting structure 3 includes a first reflecting region f1 and a second reflecting region f2 arranged along the Y direction. The distance between the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between the second reflecting region f2 and the metasurface radiating structure 2. Specifically, the reflecting structure 3 may include a first part 31 and a second part 32 arranged along the Y direction. The surface of the first part 31 facing the metasurface radiating structure 2 is the first reflecting region f1, and the surface of the second part 32 facing the metasurface radiating structure 2 is the second reflecting region f2. The first part 31 and the second part 32 can both be plate-like structures of uniform thickness or plate-like structures of non-uniform thickness, as long as the distance between the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between the second reflecting region f2 and the metasurface radiating structure 2. The first part 31 is laid flat on a metal base plate 41, and the first part 31 is parallel to the Y direction. The second part 32 is inclined along the Y direction. One end of the second part 32 abuts against the first part 31, and the other end abuts against the metal frame 42, so that the second part 32 and the metal base plate 41 are set at an angle θ, thereby making the second reflecting region f2 set at an angle θ with the Y direction. Along the Z direction, the distance between any point of the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between any point of the second reflecting region f2 and the metasurface radiating structure 2. Compared with the antenna element shown in Figure 6, the reflecting surface F of the reflecting structure 3 in Figure 12a is discontinuous and flat, and it can be considered that the reflecting surface F of the reflecting structure 3 is partially inclined relative to the Y direction. In the antenna element shown in Figure 12a, the angle θ can be selected from angles less than or equal to 60°, such as 1°, 2°, 10°, 25°, 45°, 60°, etc.

[0101] Figure 12b shows an antenna element that is a structural variation of the antenna element shown in Figure 12a. Compared to the antenna element shown in Figure 12a, in the antenna element shown in Figure 12b, the first part 31 of the reflecting structure 3 is inclined along the Y direction, and the second part 32 of the reflecting structure 3 is parallel to the Y direction and maintains a certain distance from the metal base plate 41. Specifically, along the Y direction, one end of the first part 31 abuts against the connection between the metal base plate 41 and the metal frame 42, and the other end of the first part 31 has a certain distance from the metal base plate 41 along the Z direction, so that the first part 31 and the metal base plate 41 are set at an angle θ. The second part 32 is parallel to the metal base plate 41, one end of the second part 32 is connected to the first part 31, and the other end of the second part 32 is fixed to the metal frame 42. Along the Z direction, the distance between any point of the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between any point of the second reflecting region f2 and the metasurface radiating structure 2. In the antenna element shown in Figure 12b, the included angle θ can be selected from angles less than or equal to 60°, such as 1°, 2°, 10°, 25°, 45°, and 60°.

[0102] Figure 12c shows an antenna element that is a structural variation of the antenna element shown in Figures 12a and 12b. Compared to Figures 12a and 12b, in the antenna element shown in Figure 12c, the first part 31 and the second part 32 of the reflecting structure 3 are both tilted along the Y direction. The first reflecting region f1 of the first part 31 is set at an angle θ1 with the Y direction, and the second reflecting region f2 of the second part 32 is set at an angle θ2 with the Y direction. Along the Z direction, the distance between any point of the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between any point of the second reflecting region f2 and the metasurface radiating structure 2. It should be understood that when θ1 = θ2, the first reflecting region f1 of the first part 31 and the second reflecting region f2 of the second part 32 are coplanar, and the reflecting structure 3 at this time is equivalent to the reflecting structure 3 in Figure 6. Here, the angles θ1 and θ2 are both less than or equal to 60°.

[0103] Referring to Figures 12a to 12c, both the first reflecting region f1 and the second reflecting region f2 of the reflecting surface F are planar. It is sufficient that at least one of the first reflecting region f1 and the second reflecting region f2 is set at an angle to the Y direction, and that the distance between any point of the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between any point of the second reflecting region f2 and the metasurface radiating structure 2. It should be understood that the form of the reflecting structure 3 can also be replaced with the wedge-shaped structure in Figure 11, as long as the first reflecting region f1 and the second reflecting region f2 meet the requirements of the above embodiment. For the entire antenna element, in order to achieve good radiation effect, along the Z direction, that is, the arrangement direction of the metasurface radiating structure 2 and the reflecting surface F, the excitation unit 1 and the second reflecting region f2 are positioned opposite each other.

[0104] Figure 13 shows a cross-sectional view of an antenna element. The reflecting surface F of the reflecting structure 3 includes a first reflecting region f1 and a second reflecting region f2 arranged along the Y direction. The distance between the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between the second reflecting region f2 and the metasurface radiating structure 2. Compared with the antenna elements shown in Figures 12a to 12c, the first part 31 and the second part 32 of the reflecting structure 3 in Figure 13 are not directly connected. The first part 31 and the second part 32 are connected by a connecting part 33, and the surface of the connecting part 33 facing the metasurface radiating structure 2 is a transition region f3. It can be considered that the reflecting surface F includes the first reflecting region f1, the second reflecting region f2, and the transition region f3 connecting the first reflecting region f1 and the second reflecting region f2. The first reflecting region f1 and the second reflecting region f2 can be arranged in a parallel manner. For example, the connecting part 33 can be connected between the first part 31 and the second part 32 in a manner perpendicular to the metal base plate 41 as shown in Figure 13. The second reflecting region f2 is used to connect one end a1 of the transition region f3 to the end a2 of the first reflecting region f1 away from the second reflecting region f2. The line connecting these two ends forms an angle θ with the Y direction. The range of this angle θ is related to the structural form of the reflecting structure 3, and θ can be selected from angles less than 90°, such as 1°, 2°, 10°, or 45°. Of course, the selection of the angle θ must be implemented while ensuring the radiation function of the antenna element is met; in some cases, the shape and volume of the antenna element also need to be considered.

[0105] Figure 14 shows a structural variation of the antenna element shown in Figure 13. Compared to Figure 13, the connecting portion 33 in Figure 14 is tilted. To ensure that the line connecting the end a1 of the second reflection region f2 used to connect the transition region f3 and the end a2 of the first reflection region f1 away from the second reflection region f2 forms an angle θ with the Y direction, the angle between the transition region f3 and the Y direction is greater than the angle θ. Here, the angle θ can be selected to be less than 90°.

[0106] Referring to Figures 13 and 14, the first reflecting region f1 and the second reflecting region f2 of the reflecting surface F are both planar and parallel to each other, and are connected by a transition region f3 to form a continuous reflecting surface F. The distance between the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between the second reflecting region f2 and the metasurface radiating structure 2, which satisfies the condition that the distance between any point of the first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between any point of the second reflecting region f2 and the metasurface radiating structure 2.

[0107] It should be understood that the implementation methods of the first reflection region f1 and the second reflection region f2 shown in Figures 12a to 12c can also be applied to the reflecting surface F shown in Figures 13 and 14. That is, at least one of the first reflection region f1 and the second reflection region f2 in Figures 13 and 14 can also be set at an angle relative to the Y direction, as long as the distance between any part of the first reflection region f1 and the metasurface radiation structure 2 is greater than the distance between any part of the second reflection region f2 and the metasurface radiation structure 2.

[0108] Figure 15a shows a cross-sectional view of an antenna element. The reflecting surface F of the reflecting structure 3 includes one or more first reflecting regions f1 and one or more second reflecting regions f2. The distance between any point of any first reflecting region f1 and the metasurface radiating structure 2 is greater than the distance between any point of an adjacent second reflecting region f2 and the metasurface radiating structure 2. For example, the second reflecting region f2 is a convex surface protruding from the first reflecting region f1 into the metasurface radiating structure 2. The second reflecting regions f2 extend along the X direction, and when there are multiple second reflecting regions f2, they are spaced apart along the Y direction. In the antenna element shown in Figure 15a, there are two second reflecting regions f2, spaced apart along the Y direction, and the cross-section of the second reflecting region f2 perpendicular to the X direction is, for example, rectangular. In some embodiments, the reflective structure 3 may specifically include a planar portion 34 and a ridge portion 35. The planar portion 34 is laid flat on the metal base plate 41 and parallel to the Y direction. The ridge portion 35 is elongated and protrudes from the planar portion 34 toward the metasurface radiating structure 2, extending along the X direction. Exemplarily, two ridge portions 35 are spaced apart along the Y direction, and three planar portions 34 are distributed along the Y direction. Along the Y direction, one planar portion 34 is located between two ridge portions 35, and the other two planar portions 34 are located on either side of the two ridge portions 35. The planar portion 34 and the ridge portion 35 of the reflective structure 3 can be fabricated from a sheet metal using a bending process. The surface of the planar portion 34 facing the metasurface radiating structure 2 is the first reflective region f1, and the surface of the ridge portion 35 facing the metasurface radiating structure 2 is the second reflective region f2. The ridge portion 35 can be considered to be U-shaped, such that the cross-section of the second reflective region f2 perpendicular to the X direction is rectangular between the X direction and the Y direction. Here, the first reflective region f1 and at least a portion of the second reflective regions f2 are parallel to the metasurface radiating structure 2, and the distance between the second reflective region f1 and the metasurface radiating structure 2 is greater than the distance between the second reflective region f2 and the metasurface radiating structure 2. Specifically, taking the first reflective region f1 located between the metal frame 42 and an adjacent second reflective region f2 as an example, along the Y direction, one end b2 of the first reflective region f1 is connected to the junction of the metal frame 42 and the metal base plate 41, and the other end is connected to a second reflective region f2. The line connecting the end b2 of the first reflective region f1 connected to the metal frame 42 and the edge b1 of the second reflective region f2 near the first reflective region f1 forms an angle θ with the Y direction. Here, the angle θ can be less than 90°, and exemplarily, θ can be an angle less than 90° such as 1°, 2°, 10°, 25°, 45°, 60°, or 85°.

[0109] Referring to Figure 15a, each second reflective region f2 can be considered to include a ridge surface facing the metasurface radiating structure 2. The surface of the ridge-shaped portion 35 facing the metasurface radiating structure 2 is the ridge surface, which is shown in shaded form in Figure 15a. The ridge surface in Figure 15a is parallel to the metal base plate 41 and also parallel to the metasurface radiating structure 2; this ridge surface is a plane. At this point, the ridge surface can be considered as part of the second reflective region f2.

[0110] Figure 15b shows a structural variation of the antenna element shown in Figure 15a. In some embodiments, each second reflecting region f2 includes a ridge surface inclined relative to the metal base plate 41, the included angle of the ridge surface relative to the metal base plate 41 being greater than or equal to the included angle θ. In this case, the ridge surface included by the second reflecting region f2 is planar, and the cross section of the second reflecting region f2 perpendicular to the X direction is triangularly arranged between the X direction and the Y direction. Here, the included angle θ can be selected to be less than or equal to 90°. For example, θ can be selected as an angle less than or equal to 90°, such as 1°, 2°, 10°, 25°, 45°, 60°, 85°, 90°, etc.

[0111] Figure 15c shows another structural variation of the antenna element shown in Figure 15a. As shown in Figure 15c, the ridge 35 of the reflective structure 3 is arched, making the cross-section of the second reflective region f2 perpendicular to the X direction semi-circular with respect to the Y direction. Taking the first reflective region f1 located between the metal frame 42 and an adjacent second reflective region f2 as an example, along the Y direction, one end b2 of the first reflective region f1 is connected to the junction of the metal frame 42 and the metal base plate 41, and the other end is connected to a second reflective region f2. The line connecting the end b2 of the first reflective region f1 connected to the metal frame 42 and tangent to the second reflective region f2 forms an angle θ with the Y direction; the point where this line is tangent to the second reflective region f2 can be considered point b1. In this case, the ridge surface can be considered the second reflective region f2.

[0112] Referring to Figures 15a to 15c, by changing the shape of the ridge portion 35, the shape of the second reflective region f2 perpendicular to the X direction and relative to the Y direction can be trapezoidal, triangular, polygonal, or irregular, as long as the distance between the second reflective region f2 and the metasurface radiation structure 2 is less than the distance between the first reflective region f1 and the metasurface radiation structure 2. The first reflective region f1 and the ridge-shaped second reflective region f2 can be combined in specific implementations with the implementation forms of the first reflective region f1 and the ridge-shaped second reflective region f2 shown in Figures 12a to 14. For example, one or more of the first reflective regions f1 in Figures 15a and 15b can be arranged at an angle.

[0113] In some embodiments, the reflecting surface F is parallel to the Y direction, and the structure of the metasurface radiating structure 2 is adjusted such that at least two positions of the reflecting surface F are not equidistant from the metasurface radiating structure 2. As shown in Figure 16a, the metasurface radiating structure 2 is inclined along the Y direction. The metasurface radiating structure 2 is, in an example, a continuous plate shape, and is set at an angle θ relative to the metal base plate 41. Here, the angle θ can be less than or equal to 45°. For example, θ can be an angle less than or equal to 45°, such as 1°, 2°, 10°, 25°, or 45°.

[0114] For example, multiple metasurface units 22 of the metasurface radiating structure 2 are disposed on the same surface of the dielectric substrate 21 and have the same height. It can be considered that the dielectric substrate 21 is disposed at an angle θ relative to the metal base plate 41. The reflective structure 3 is in the shape of a continuous plate, and the reflective structure 3 is laid flat on the metal base plate 41 and parallel to the Y direction. Along the Y direction, the distance between the reflective surface F of the metasurface radiating structure 2 and the reflective structure 3 varies, and for example, gradually decreases along the Y direction as indicated by the arrow.

[0115] As shown in Figure 16b, an antenna element includes a metasurface radiating structure 2 comprising a first radiating region q1 and a second radiating region q2 arranged along the Y direction. The distance between the first radiating region q1 and the reflecting surface F of the reflecting structure 3 is greater than the distance between the second radiating region q2 and the reflecting surface F. At least one of the first radiating region q1 and the second radiating region q2 is positioned at an angle θ with the metal base plate 41. This angle θ can be less than or equal to 45°. When both the first radiating region q1 and the second radiating region q2 are positioned at an angle θ with the metal base plate 41, and the first radiating region q1 and the second radiating region q2 are coplanar, the structure is equivalent to the metasurface radiating structure 2 shown in Figure 16a.

[0116] As shown in Figure 17, an antenna element has a metasurface radiating structure 2 that is stepped along the Y direction. Exemplarily, the metasurface radiating structure 2 includes a first radiating region q1 and a second radiating region q2 arranged along the Y direction. The distance between the first radiating region q1 and the reflecting surface F of the reflecting structure 3 is greater than the distance between the second radiating region q2 and the reflecting surface F.

[0117] In this embodiment, the metasurface radiating structure 2 specifically includes a dielectric substrate 21 and a plurality of metasurface units 22 disposed on the surface of the dielectric substrate 21. The metasurface units 22 are used to generate electromagnetic wave signals by being excited by the excitation unit 1. It can be considered that the plurality of metasurface units 22 form a radiating structure for radiating electromagnetic wave signals. Changing the distance between the electromagnetic signal and the reflecting surface F of the reflecting structure 3 can be considered as changing the distance between a portion of the plurality of metasurface units 22 and the reflecting surface F of the reflecting structure 3. Generally, the metasurface units 22 are disposed on the surface of the dielectric substrate 21 and protrude from the surface of the dielectric substrate 21. In some embodiments, the plurality of metasurface units 22 can be disposed on different surfaces of the dielectric substrate 21, so that the distance between different metasurface units 22 and the reflecting surface F of the reflecting structure 3 is different, which can also change the phase of the electromagnetic wave signal at different positions to achieve the purpose of beam deflection.

[0118] As shown in Figure 18a, a metasurface radiating structure 2 includes a dielectric substrate 21 and a plurality of metasurface units 22. The plurality of metasurface units 22 are divided into a portion of metasurface units 22a and another portion of metasurface units 22b according to different distribution positions. Exemplarily, the dielectric substrate 21 has a first surface b1 and a second surface b2 opposite to each other along the thickness direction. A portion of the metasurface units 22a is disposed on the first surface b1 and protrudes from the first surface b1, and another portion of the metasurface units 22b is disposed on the second surface b2 and protrudes from the second surface b2.

[0119] Figure 18b shows an antenna element having the metasurface radiating structure 2 shown in Figure 18a. As shown in Figure 18b, the surface of the dielectric substrate 21 of the metasurface radiating structure 2 facing the reflecting surface F of the reflecting structure 3 is the second surface b2, and the surface of the dielectric substrate 21 away from the reflecting surface F of the reflecting structure 3 is the first surface b1. Along the Y direction, a portion of the metasurface elements 22a and another portion of the metasurface elements 22b are arranged, with a portion of the metasurface elements 22a disposed on the first surface b1 of the dielectric substrate 21 away from the reflecting structure 3, and the other portion of the metasurface elements 22b disposed on the second surface b2 of the dielectric substrate 21 facing the reflecting structure 3. Along the Z direction, the dielectric substrate 21 has a certain thickness, such that the distance between a portion of the metasurface elements 22a and the reflecting surface F of the reflecting structure 3 is smaller than the distance between the other portion of the metasurface elements 22b and the reflecting surface F of the reflecting structure 3.

[0120] It should be understood that a portion of the metasurface units 22a in Figure 18b can be considered to form the first radiation region q1, while another portion of the metasurface units 22b can form the second radiation region q2.

[0121] Figure 19 shows a structural variation of the metasurface radiation structure 2 shown in Figure 18a. As shown in Figure 19, in some embodiments, the metasurface radiation structure 2 may include multiple stacked dielectric substrates 21, and multiple metasurface units 22 may be divided into at least two parts and respectively disposed on the top and bottom dielectric substrates 21. Exemplarily, Figure 19 illustrates two stacked dielectric substrates 21, namely dielectric substrate 21a and dielectric substrate 21b. The surface of dielectric substrate 21a facing away from dielectric substrate 21b can be considered as the first surface b1, and a portion of the metasurface units 22a are disposed on dielectric substrate 21a and located on the first surface b1. The surface of dielectric substrate 21b facing away from dielectric substrate 21a can be considered as the second surface b2, and another portion of the metasurface units 22b are disposed on dielectric substrate 21b and located on the second surface b2.

[0122] It should be understood that in some embodiments, the metasurface radiating structure 2 includes three or more layers of dielectric substrate 21. It can be considered that adding at least one additional dielectric substrate 21 to the dielectric substrate 21a and dielectric substrate 21b shown in FIG19 can obtain a dielectric substrate 21 including three or more layers.

[0123] In some embodiments, based on the structure of the metasurface radiating structure 2, multiple metasurface units 22 can be regionally designed along a certain direction, such that the multiple metasurface units 22 are distributed in a stepped manner. As shown in FIG20a, multiple metasurface units 22 are disposed on the same surface of the dielectric substrate 21. The multiple metasurface units 22 are divided into a portion of metasurface units 22a and another portion of metasurface units 22b. Along the direction perpendicular to the dielectric substrate 21, the other portion of metasurface units 22b protrudes from the dielectric substrate 21 by a height h1, and the portion of metasurface units 22b protrudes from the dielectric substrate 21 by a height h2, where h1 ≠ h2. For the overall structure of the metasurface radiating structure 2, the side of the metasurface radiating structure 2 used to dispose of the metasurface units 22 is stepped. Exemplarily, h1 is greater than h2.

[0124] Figure 20b is a cross-sectional schematic diagram of an antenna element having the metasurface radiating structure 2 shown in Figure 20a. As shown in Figure 20b, multiple metasurface elements 22 are located on the side of the metasurface radiating structure 2 facing the reflecting surface F of the reflecting structure 3, that is, the multiple metasurface elements 22 are disposed on the surface of the dielectric substrate 21 facing the reflecting surface F of the reflecting structure 3. The multiple metasurface elements 22 include a portion of metasurface elements 22a and another portion of metasurface elements 22b arranged along the Y direction. The height of the other portion of metasurface elements 22b protruding from the surface of the dielectric substrate 21 is greater than the height of the other portion of metasurface elements 22a protruding from the surface of the dielectric substrate 21. Therefore, the distance between the other portion of metasurface elements 22a and the reflecting surface F of the reflecting structure 3 is greater than the distance between the other portion of metasurface elements 22b and the reflecting surface F of the reflecting structure 3. In Figure 20b, the other portion of metasurface elements 22a can be considered to form a first radiating region q1, and the other portion of metasurface elements 22b can form a second radiating region q2.

[0125] Referring to Figures 20a and 20b, multiple metasurface units 22 can be distributed in a stepped manner, thereby changing the distance between different positions of the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3. In this example, some metasurface units 22a and others 22b are distributed in a two-step manner along the Y direction. In specific implementations, the step may have three, four, or even more steps, which will not be illustrated here.

[0126] In the antenna units provided in the above embodiments, some embodiments are based on changing only the reflecting surface F of the reflecting structure 3, and some are based on changing only the metasurface radiating structure 2. In practical applications, the structure of the reflecting surface F of the reflecting structure 3 and the structure of the metasurface radiating structure 2 can be changed at the same time, so that the distance between the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 is different at different positions along the Y direction.

[0127] In some embodiments, the structure between the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 is combined with the structures shown in Figures 6 and 16a. As shown in Figure 21, in an antenna unit, the metasurface units 22 of the metasurface radiating structure 2 are disposed on the same surface of the dielectric substrate 21 and have equal heights. The metasurface radiating structure 2 has a continuous plate-like structure, and the reflecting structure 3 also has a continuous plate-like structure. The dielectric substrate 21 of the metasurface radiating structure 2 and the metal base plate 41 are set at an angle θ1, and the reflecting surface F of the reflecting structure 3 and the metal base plate 41 are set at an angle θ2, where θ1 ≠ θ2. Exemplarily, θ1 is greater than θ2. Alternatively, θ1-θ2 can be θ as described in the above embodiments, which can also achieve the purpose of changing the phase of the electromagnetic signal excited at different positions of the metasurface radiating structure 2, thereby achieving beam deflection.

[0128] It should be understood that different implementations of the reflective surface F of the reflective structure 3, which is tilted relative to the Y direction, has a stepped distribution, or has a ridge, can also be combined with the metasurface radiating structure 2, which is tilted relative to the Y direction and has a stepped distribution. This results in different distances between the metasurface radiating structure 2 and the reflective surface F of the reflective structure 3 at different positions along the Y direction, further expanding the implementation methods of the antenna element. Furthermore, combining different methods can achieve a larger radiation beam deflection angle, optimize sidelobes, and improve the directivity coefficient.

[0129] In summary, in the antenna unit provided in this application embodiment, the distance between different positions of the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 varies along the Y direction. For the base station antenna 100, the Y direction is the vertical direction of the radiated beam of the base station antenna 100, thereby changing the ground clearance of different regions of the metasurface radiating structure 2. When the electromagnetic signals generated by the excitation unit 1 in different regions of the metasurface radiating structure 2 are reflected by the reflecting surface F, a phase difference is generated, thereby changing the direction of the radiated beam and achieving beam deflection. When the different structures of the metasurface radiating structure 2 and the reflecting surface F of the reflecting structure 3 are combined, the beamforming capability of the vertical plane of the radiated beam can be further expanded, achieving a larger beam deflection angle. Furthermore, by combining the number and placement of the excitation units 1, the sidelobe gain of the radiated beam can be selectively optimized, improving the directivity coefficient.

[0130] The base station antenna 100 with the aforementioned antenna elements has better beam deflection adjustment capability and improved sidelobe gain of antenna radiation. When there are multiple antenna elements, they can be arranged in an array to form an array antenna. After arranging multiple antenna elements in an array to form an array antenna, the isolation between antenna elements in the antenna array is low, the distortion of the radiation pattern is small, and the performance of the wireless network can be improved.

[0131] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An antenna element, characterized in that, The antenna unit includes an excitation unit, a metasurface radiating structure, and a reflective surface; The metasurface radiating structure and the reflecting surface are arranged at relative intervals, and the excitation unit is used to excite the metasurface radiating structure to radiate electromagnetic signals. The reflective surface is used to reflect the signal radiated by the metasurface radiation structure, and the distance between the metasurface radiation structure and the reflective surface varies along a first direction.

2. The antenna element as described in claim 1, characterized in that, The reflective surface includes a first reflective region and a second reflective region arranged along the first direction; The distance between the first reflective region and the metasurface radiating structure is greater than the distance between the second reflective region and the metasurface radiating structure.

3. The antenna element as described in claim 2, characterized in that, Both the first and second reflective regions are planar, and at least one of the first and second reflective regions is set at an angle to the first direction.

4. The antenna element as described in claim 3, characterized in that, Both the first reflective region and the second reflective region are set at an angle to the first direction, and the first reflective region and the second reflective region are coplanar.

5. The antenna element as described in claim 2, characterized in that, The first reflective region and the second reflective region are both planar and parallel to each other, and the reflective surface includes a transition region connecting the first reflective region and the second reflective region.

6. The antenna element as described in claim 2, characterized in that, The second reflective region includes ridges that protrude from the metasurface radiation structure, and the number of ridges is one or more.

7. The antenna element as described in claim 6, characterized in that, When there are multiple ridges, the multiple ridges are arranged at intervals along the first direction.

8. The antenna element as described in claim 6 or 7, characterized in that, The ridge surface can be a plane, an arc, or an inclined plane.

9. The antenna element as described in any one of claims 2-8, characterized in that, Along the arrangement direction of the metasurface radiation structure and the reflective surface, the excitation unit is positioned opposite the second reflective region.

10. The antenna element as described in any one of claims 1-9, characterized in that, The metasurface radiative structure includes a dielectric substrate and a plurality of metasurface units fixed to the dielectric substrate; Along the first direction, the plurality of metasurface units include a portion of metasurface units and another portion of metasurface units, wherein the distance between the portion of metasurface units and the reflective surface is greater than the distance between the other portion of metasurface units and the reflective surface.

11. The antenna element as claimed in claim 10, characterized in that, The metasurface units and the metasurface units are disposed on the same surface of the dielectric substrate, and the dielectric substrate is disposed at an angle to the first direction.

12. The antenna element as described in claim 11, characterized in that, The reflective surface is set at an angle to the first direction, and the angle between the dielectric substrate and the first direction is not equal to the angle between the reflective surface and the first direction.

13. The antenna element as described in claim 10, characterized in that, One portion of the metasurface units are disposed on the surface of the dielectric substrate facing away from the reflective surface, and the other portion of the metasurface units are disposed on the surface of the dielectric substrate facing the reflective surface.

14. The antenna element as described in any one of claims 10-13, characterized in that, The excitation unit is fixed to the surface of the dielectric substrate.

15. The antenna element as described in claim 14, characterized in that, At least one excitation unit is provided on each of the two surfaces of the dielectric substrate.

16. The antenna element as described in any one of claims 1-13, characterized in that, The excitation unit is disposed between the reflective surface and the metasurface radiation structure.

17. The antenna element as described in any one of claims 1-16, characterized in that, Along the first direction, the excitation unit is offset from the center of the metasurface radiation structure.

18. A base station antenna, characterized in that, It includes a filter circuit and an antenna element as described in any one of claims 1-17, wherein the filter circuit is electrically connected to the antenna element.

19. A communication device, characterized in that, It includes at least two base station antennas as described in claim 18.

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