Filtering apparatus, base station antenna and base station device

Abstract

Provided in the present application is a filtering apparatus, comprising a first frequency selective surface and a shielding cavity, wherein the first frequency selective surface comprises a first surface and a second surface which are opposite each other; the first surface is provided with a first electrically conductive pattern formed by metal line segments; the second surface is provided with a second electrically conductive pattern formed by providing slots in a metal surface, and the second surface comprises a first region, a second region, and a third region between the first region and the second region; the first region and the second region are provided with the slots; and a projection of the shielding cavity on the second surface is located in the third region, and the shielding cavity is used for providing a feed network. Adjusting the pattern size of a first electrically conductive pattern can change a cut-off frequency of a filtering apparatus, adjusting the slots size of a second electrically conductive pattern can change the wave transmission characteristic of the filtering apparatus, and a shielding cavity can avoid electromagnetic leakage and prevent a shielding cavity body from adversely affecting a filtering effect, thereby realizing the integrated design of a passive antenna and an active antenna.

Description

A filtering device, a base station antenna, and base station equipment.

[0001] This application claims priority to Chinese Patent Application No. 202411816478.1, filed on December 11, 2024, entitled "A Filtering Device, Base Station Antenna and Base Station Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of communication technology, and more specifically, to a filtering device, a base station antenna, and base station equipment. Background Technology

[0003] As 5G technology continues to evolve and mature, tower masts (commonly known as masts) for installing base station equipment are becoming increasingly valuable. Constructing new tower masts requires comprehensive consideration of the existing cellular base station network layout, strict adherence to safety regulations, and assessment of potential public health impacts. Currently, a more ideal solution is to implement tower mast resource sharing, integrating active and passive antennas onto the same tower mast. Currently, active and passive antennas are generally designed as separate units, with the active antenna typically positioned below the passive antenna, resulting in a limited coverage area. In the few existing integrated designs of active and passive antennas, the active antenna is located behind the passive antenna. Since active and passive antennas usually operate in different frequency bands, a filter is needed between them to ensure proper functioning. However, existing filters are ineffective and susceptible to interference from the surrounding feed network, which can negatively impact the normal operation of both active and passive antennas after integration. Summary of the Invention

[0004] This application provides a filtering device, a base station antenna, and base station equipment, which improves the filtering effect of the filtering device and reduces interference, aiming to better realize the integrated design of passive and active antennas in the base station antenna.

[0005] In a first aspect, a filtering device is provided, including a first frequency selective surface and a shielding cavity. The first frequency selective surface includes a first surface and a second surface opposite to each other. The first surface is provided with a first conductive pattern formed by metal line segments, and the second surface is provided with a second conductive pattern formed by gaps in the metal surface. The second surface includes a first region, a second region, and a third region between the first region and the second region. The first region and the second region are provided with the gaps. The projection of the shielding cavity on the second surface is located in the third region. The shielding cavity is used to provide a power supply network.

[0006] In the filtering device provided in this application embodiment, the first conductive pattern can be used to control the cutoff frequency of the filtering device. Adjusting the size of the first conductive pattern can change the cutoff frequency of the filtering device. The second conductive pattern can be used to control the transmission bandwidth of the filtering device. Adjusting the size of the gaps in the second conductive pattern can change the transmission characteristics of the filtering device. Therefore, this filtering device can simultaneously control the cutoff frequency and transmission bandwidth, resulting in good filtering performance. The shielding cavity can effectively isolate signals in its internal feed network, achieving low-loss signal transmission and avoiding electromagnetic leakage, thus preventing adverse effects on the filtering performance. Furthermore, the projection of the shielding cavity on the second surface is located in the third region, avoiding the gaps in the conductive pattern, thereby preventing the shielding cavity itself from adversely affecting the filtering performance. Therefore, this filtering device facilitates better integration of passive and active antenna designs.

[0007] In some implementations of the first aspect, the first conductive pattern includes a first line segment and a second line segment, the first line segment enclosing a first non-closed region, the second line segment being located inside the first non-closed region and enclosing a second non-closed region, and a gap being present between the first line segment and the second line segment; wherein the opening direction of the first non-closed region is opposite to the opening direction of the second non-closed region.

[0008] In this implementation, the first conductive pattern can adjust the resonant zero of the frequency response curve to better reflect signals in frequency bands below the resonant zero, thereby improving the frequency selectivity of the filter and the signal quality of the passive antenna placed above the filter.

[0009] In some implementations of the first aspect, there are multiple first frequency selection surfaces, each of which intersects with a first plane. The multiple first frequency selection surfaces are configured to be arranged in the first plane to form a first grid array, and each first grid is surrounded by a number of first frequency selection surfaces of array elements.

[0010] In this implementation, the grid-like first frequency selection surface can achieve uniform filtering along the planar direction of the grid array, thereby improving the frequency selectivity and effective bandwidth of the filtering device.

[0011] In some implementations of the first aspect, the shielding cavity includes a plurality of cavity segments forming a second grid array, each second grid being surrounded by a number of cavity segments of array elements; each cavity segment is adjacent to a first frequency selective surface, and its projection onto a second surface of the adjacent first frequency selective surface lies within a third region; at least one first frequency selective surface includes a clearance region located at a position in the third region adjacent to a vertex of the first grid, the clearance region clearance a metal line segment on a first surface and clearance a gap on a second surface; the clearance region is used for cavity segments to pass through to connect with other cavity segments to form a second grid.

[0012] In this implementation, the antenna array feed network can be set up in the shielded cavity first, and then the first frequency selection surface can be set on the shielded cavity to manufacture the filter device, which is beneficial to improving the manufacturing efficiency of the filter device.

[0013] In some implementations of the first aspect, the edge of the avoidance area is attached to the outer surface of the cavity segment.

[0014] In this implementation, when the first frequency selection surface is installed on the shielding cavity, multiple first frequency selection surfaces can be arranged regularly and neatly, so that the filter device has a simple structure of periodic repetition, which is beneficial to improving the manufacturing efficiency of the filter device.

[0015] In some implementations of the first aspect, the first frequency selection surface is engaged with the cavity segment by a first edge and a second edge of the avoidance region, the first edge being perpendicular to the second edge.

[0016] In some implementations of the first aspect, the first edges of the two avoidance regions adjacent to a vertex of the first grid are located on both sides of the shielding cavity.

[0017] In this implementation, when the first frequency selective surface is installed on the shielded cavity, there is a large gap between adjacent first frequency selective surfaces. This facilitates installation without reducing frequency selectivity and helps improve the manufacturing efficiency of the filter device.

[0018] In some implementations of the first aspect, the first and second grids are polygonal grids.

[0019] In this implementation, multiple first frequency selection surfaces can be arranged regularly and neatly, thus giving the filter device a simple, periodically repeating structure, which is beneficial to improving the manufacturing efficiency of the filter device.

[0020] In some implementations of the first aspect, the filtering device further includes at least one second frequency selection surface perpendicular to the first frequency selection surface, the second frequency selection surface being provided with a third conductive pattern.

[0021] In this implementation, the second frequency selection surface can adjust the reflection phase of the filter unit at frequencies below the roll-off transition band, thereby increasing the antenna gain and reducing the beamwidth.

[0022] In some implementations of the first aspect, at least one of the first conductive pattern, the second conductive pattern, or the third conductive pattern is an axisymmetric pattern and / or a centrally symmetric pattern.

[0023] In this implementation, repeating axisymmetric and / or centrally symmetric patterns can reduce design complexity and improve the frequency selectivity and effective bandwidth of the filter.

[0024] In a second aspect, a base station antenna is provided, the base station antenna including a filtering device as described in any implementation of the first aspect, and a plurality of antenna arrays, wherein a feeding network for the antenna arrays is disposed within the shielding cavity of the filtering device, and the plurality of antenna arrays are respectively disposed on both sides of the filtering device.

[0025] In some implementations of the second aspect, multiple antenna arrays located on one side of the filtering device operate in multiple operating frequency bands.

[0026] Thirdly, a base station device is provided, the base station device including a base station antenna as described in any implementation of the second aspect, and a power supply for supplying power to the base station antenna. Attached Figure Description

[0027] Figure 1 is a schematic diagram of a filtering device provided in an embodiment of this application.

[0028] Figure 2 is a schematic diagram of the structure of a filtering unit provided in an embodiment of this application.

[0029] Figure 3 is a schematic diagram of the structure of a filtering unit provided in an embodiment of this application.

[0030] Figure 4 is a schematic diagram of a conductive pattern and its equivalent circuit provided in an embodiment of this application.

[0031] Figure 5 is a schematic diagram of the structure of a shielding cavity provided in an embodiment of this application.

[0032] Figures 6 to 8 are frequency response curves of the filtering unit provided in the embodiments of this application.

[0033] Figure 9 is a schematic diagram of the structure of a filtering unit provided in an embodiment of this application.

[0034] Figure 10 is a frequency response curve of a filter unit provided in an embodiment of this application.

[0035] Figure 11 is a schematic diagram of the structure of a filtering unit provided in an embodiment of this application.

[0036] Figure 12 is a schematic diagram of the structure of a base station antenna provided in an embodiment of this application. Detailed Implementation

[0037] First, let's explain the technical terms related to this application.

[0038] The shielding cavity in an antenna array is typically made of conductive materials (such as metal), forming a closed or partially closed space that isolates the internal circuitry from the external electromagnetic environment. The main function of the shielding cavity is to prevent external electromagnetic waves from entering the device and to prevent electromagnetic radiation generated internally from leaking into the external environment, thereby ensuring the normal operation and stable performance of the antenna array. By carefully designing and optimizing the shape, size, and materials of the shielding cavity, the anti-interference capability and electromagnetic compatibility of the antenna array can be effectively improved.

[0039] A frequency selective surface (FSS) is a special structure composed of periodically arranged frequency-selective cells. The metal patch cells act like filters, exhibiting total internal reflection within a specific frequency range, effectively blocking or reflecting electromagnetic waves. The aperture cells, on the other hand, allow electromagnetic waves to pass through at the corresponding frequencies. Through precise design and arrangement, the FSS enables precise control and filtering of electromagnetic waves within a specific region of the electromagnetic spectrum.

[0040] The transmission coefficient is a physical quantity that describes the efficiency with which electromagnetic waves or other waves are transmitted from one medium to another when passing through a medium boundary. When a wave encounters the interface between two different media, some energy may be reflected back to the original medium, while the remaining energy will pass through the interface into the new medium. The transmission coefficient is the ratio of the amplitude of the transmitted wave to the amplitude of the incident wave, and is usually expressed in logarithmic form.

[0041] Transmission bandwidth refers to the frequency range within which a medium allows electromagnetic waves to pass through without significant attenuation. Some materials may exhibit high transmittance in specific frequency bands, while absorbing or reflecting most incident waves in other bands. The width and location of the transmission bandwidth determine the suitable applications for that material.

[0042] The frequency response curve shows how the ratio of the system's output to its input signal (i.e., the transmission coefficient) changes with frequency, indicating how much energy the measured medium allows to pass through at different frequencies. The transmission bandwidth is a set of multiple frequency bands on the frequency response curve where the transmission coefficient remains relatively constant and high.

[0043] The frequency response of the FSS (Fluidic Seismic Array) is tested, and its frequency response curve includes a roll-off transition band. The roll-off transition band describes the process by which the FSS gradually transitions from a state of total transmission (or total reflection) to another state (such as enhanced reflection or reduced transmission) within a specific frequency range. Specifically, the roll-off transition band typically exhibits a smooth transition, and its width and shape depend on the design parameters of the FSS, such as cell shape, size, arrangement, and dielectric material. The existence of the roll-off transition band enables the FSS to achieve precise control of electromagnetic waves within a specific frequency range.

[0044] Furthermore, frequency response testing can be specifically divided into transverse electric wave (TE) mode testing and transverse magnetic wave (TM) mode testing. TE mode refers to a propagation mode where the longitudinal component of the electric field is zero in the direction of electromagnetic wave propagation, while the longitudinal component of the magnetic field is not zero. TM mode refers to a propagation mode where the longitudinal component of the magnetic field is zero in the direction of electromagnetic wave propagation, while the longitudinal component of the electric field is not zero. These two modes represent different distribution characteristics of the electric and magnetic fields, respectively, and can cover most electromagnetic wave propagation scenarios. Therefore, by testing these two modes, a relatively comprehensive understanding of the transmission characteristics of waveguides or structures can be obtained.

[0045] A resonant zero is a special point on a frequency response curve, corresponding to the frequency at which the system's transfer function is zero. In electromagnetics and electronic engineering, resonant zeros are usually associated with the oscillation or resonance phenomenon of a system. When a system oscillates at its resonant frequency, its output signal is significantly enhanced, while at a resonant zero, the system's output signal weakens or even disappears. By adjusting system parameters, such as inductance and capacitance, the location and number of resonant zeros can be changed, thereby optimizing the system's frequency response characteristics.

[0046] As 5G technology continues to evolve and mature, tower masts (commonly known as masts) for installing base station equipment are becoming increasingly valuable. Constructing new tower masts requires comprehensive consideration of the existing cellular base station network layout, strict adherence to safety regulations, and assessment of potential public health impacts. Currently, a more ideal solution is to implement tower mast resource sharing, integrating active and passive antennas onto the same tower mast. Currently, active and passive antennas are generally designed as separate units, with the active antenna typically positioned below the passive antenna, resulting in a limited coverage area. In the few existing integrated designs of active and passive antennas, the active antenna is located behind the passive antenna. Since active and passive antennas usually operate in different frequency bands, a filter is needed between them to ensure proper functioning. However, existing filters are ineffective and susceptible to interference from the surrounding feed network, which can negatively impact the normal operation of both active and passive antennas after integration.

[0047] In view of this, this application provides a filtering device, including a first frequency selective surface and a shielding cavity. The first frequency selective surface includes a first surface and a second surface opposite to each other. The first surface is provided with a first conductive pattern formed by metal line segments, and the second surface is provided with a second conductive pattern formed by gaps in the metal surface. The second surface includes a first region, a second region, and a third region between the first region and the second region. The first region and the second region are provided with the gaps. The projection of the shielding cavity on the second surface is located in the third region. The shielding cavity is used to set up a power supply network.

[0048] In the filtering device provided in this application embodiment, the first conductive pattern can be used to control the cutoff frequency of the filtering device. Adjusting the size of the first conductive pattern can change the cutoff frequency of the filtering device. The second conductive pattern can be used to control the transmission bandwidth of the filtering device. Adjusting the size of the gaps in the second conductive pattern can change the transmission characteristics of the filtering device. Therefore, this filtering device can simultaneously control the cutoff frequency and transmission bandwidth, resulting in good filtering performance. The shielding cavity can effectively isolate signals in its internal feed network, achieving low-loss signal transmission and avoiding electromagnetic leakage, thus preventing adverse effects on the filtering performance. Furthermore, the projection of the shielding cavity on the second surface is located in the third region, avoiding the gaps in the conductive pattern, thereby preventing the shielding cavity itself from adversely affecting the filtering performance. Therefore, this filtering device facilitates better integration of passive and active antenna designs.

[0049] In some embodiments, a split-architecture design can adversely affect the coverage range of the active antenna. To integrate passive and active antennas, a frequency selection device is needed that can adapt to the operating modes of different antennas; that is, to achieve reflective characteristics for the passive antenna and high electromagnetic transparency characteristics for the active antenna. If the operating frequency bands of the active and passive antennas are very close, the frequency selection device needs to have a highly steep frequency selectivity. Furthermore, if it is desired to integrate active antennas of different frequency bands onto a single passive antenna, a higher bandwidth requirement is placed on the frequency selection device. The filtering device provided in this application can simultaneously possess high frequency selectivity and effective bandwidth, thereby achieving an integrated design of passive and active antennas.

[0050] In some embodiments, FIG1 shows a schematic diagram of a filtering device. To clearly illustrate the arrangement of the filtering units in the filtering device, FIG1(a) shows a filtering unit array 110 and multiple planar FSS arrays 120, wherein the planar FSS arrays 120 are provided with multiple third conductive patterns 130. In one possible implementation, the filtering unit array 110 in FIG1(a) can be used as the filtering device of this application, and a combination of multiple planar FSS arrays 120 and filtering unit array 110 can also be used as the filtering device 100 of this application. It should be understood that the planar FSS array 120 can also be arranged below the filtering unit array 110.

[0051] In some embodiments, Figure 1(b) shows the filtering device viewed from another direction, revealing the connection between the shielding cavity and the mesh-like shielding cavity.

[0052] It should be understood that the structural schematic diagram of the filter unit array shown in Figure 1 only represents the arrangement of the filter units. The specific structure of the filter units will be described in detail in subsequent embodiments. The structural schematic diagram of the filter unit shown in Figure 1 should not be construed as a limitation on the technical solution of this application.

[0053] In some embodiments, the filtering device 100 shown in FIG. 1 includes a plurality of filtering units 200, and FIG. 2 shows a schematic diagram of the structure of the filtering unit 200. Specifically, the filtering device 100 includes a plurality of filtering units arranged along the xy plane, and the filtering unit 200 includes a plurality of first frequency selection surfaces 210 perpendicular to the xy plane. The substrate of the first frequency selection surface 210 is a dielectric material such as a printed circuit board (PCB), and includes a first surface 211 and a second surface 212 opposite to each other; wherein, the first surface 211 is provided with a first conductive pattern 241, the second surface 212 is provided with a second conductive pattern, and the second conductive pattern is provided with gaps 242. In one possible implementation, the conductive pattern is set on the substrate by a PCB etching process.

[0054] In some embodiments, the number of first frequency selection surfaces is multiple, each first frequency selection surface intersects with a first plane, and the multiple first frequency selection surfaces are configured to be arranged in the first plane to form a first grid array, each first grid being surrounded by a number of first frequency selection surfaces of array elements.

[0055] In one possible implementation, in the filtering device shown in Figure 1, the first plane is the xy plane, and each first frequency selection surface 210 is perpendicular to and intersects the first plane.

[0056] In one possible implementation, the filter unit 200 shown in FIG2 includes four first frequency selection surfaces 210 constituting a first grid, and adjacent filter units share a first frequency selection surface, i.e., the number of array elements is four. It should be understood that the plurality of first frequency selection surfaces 210 in each filter unit 200 of this application form a grid in a first plane, i.e., form a first grid.

[0057] It should be understood that adjacent first frequency selection surfaces 210 in a filter unit are electrically connected through the metal surface of the second surface, and adjacent filter units in the filter unit array are also electrically connected through the metal surface of the second surface on the first frequency selection surface. That is to say, each first frequency selection surface in the filter unit array is electrically connected.

[0058] In this implementation, the grid-like first frequency selection surface can achieve uniform filtering along the planar direction of the grid array, thereby improving the frequency selectivity and effective bandwidth of the filtering device.

[0059] In some embodiments, the substrate of the first frequency selection surface may be an insulating material, such as at least one of polyethylene terephthalate (PET), polyimide (PI), printed circuit board (PCB), epoxy resin, plastic, and ceramic. The metal surface, conductive pattern, and shielding cavity may be metallic materials, such as at least one of copper, aluminum, and silver.

[0060] In some embodiments, as shown in FIG1, the planar FSS array 120 is also referred to as the second frequency selective surface 120. That is, the filtering device further includes at least one second frequency selective surface 120 perpendicular to the plurality of first frequency selective surfaces 210, and the second frequency selective surface 120 is provided with a plurality of third conductive patterns 130. Further, as shown in FIG2, a portion of the second frequency selective surface 120 may be provided above and / or below the first frequency selective surface in the filtering unit 200. The specific design of the third conductive patterns 130 is similar to that of related technologies and will not be described in detail here.

[0061] In this implementation, the second frequency selection surface can adjust the reflection phase of the filter unit at frequencies below the roll-off transition band, thereby increasing the antenna gain and reducing the beamwidth.

[0062] In some embodiments, as shown in FIG3, the gap 242 of the second conductive pattern includes a third line segment 330 and a fourth line segment 340. The area where the third line segment 330 is located is the first region 261, and the area where the fourth line segment 340 is located is the second region 262. A third region 263 is located between the third line segment 330 and the fourth line segment 340. The shielding cavity 230 is connected to the second surface 212 within the third region 263. Specifically, FIG3(a) shows a right view of a filter unit 200, and FIG3(b) shows a front view of the second surface 212 of a first frequency selection surface. The shielding cavity 230 shown in FIG3(a) does not obstruct any part of the gap 242 of the second conductive pattern shown in FIG3(b).

[0063] In one possible implementation, the third region of the second surface is a metal surface region, which is welded to one surface of the shielding cavity to achieve an electrical connection between the second surface and the shielding cavity; or, the metal surface region and one surface of the shielding cavity are bonded together with an adhesive layer of a certain thickness to achieve a coupling connection between the second surface and the shielding cavity.

[0064] During the operation of the filtering unit, the electric field polarizes the electrons on the surface of the conductive pattern, generating a characteristic current distribution on the surface and giving it a certain inductance. The specific value of the inductance depends on the shape of the pattern. Furthermore, the gaps in the conductive pattern, polarized by the electric field, produce a capacitance effect, the specific value of which also depends on the shape of the pattern. Therefore, the conductive pattern can be equivalent to a capacitor and an inductor, thus giving it resonant response characteristics, i.e., band-pass or band-stop filtering characteristics. This allows signals within a set frequency range to pass through, while blocking signals outside the set frequency range, thereby enabling the filtering unit to perform filtering functions.

[0065] In some embodiments, FIG4 shows a schematic diagram of a first conductive pattern and its equivalent circuit. Specifically, as shown in FIG4(a), the first conductive pattern 241 includes a first line segment 310 and a second line segment 320. The first line segment 310 forms a first non-closed region, and the second line segment 320 is located inside the first non-closed region and forms a second non-closed region. There is a gap between the first line segment 310 and the second line segment 320. The opening direction of the first non-closed region is opposite to the opening direction of the second non-closed region.

[0066] Furthermore, as shown in Figure 4(b), the first line segment 310 and the second line segment 320 are used as inductors, and the second non-closed region and the gap between the first line segment and the second line segment are used as capacitors. By changing the manufacturing materials (e.g., alloys of different compositions) or length, width, gap width, etc. of the first line segment and the second line segment, the impedance values ​​of each component in the equivalent circuit can be adjusted to affect the resonant zero point of the frequency response curve, thereby adjusting the electromagnetic characteristics of the filter device.

[0067] It should be understood that the shapes of the first non-closed region and the second non-closed region can also be common polygons such as rectangles or hexagons, which can achieve the same effect as the aforementioned embodiments. This application does not limit the shape of the aforementioned non-closed region.

[0068] In this implementation, the first conductive pattern can adjust the resonant zero of the frequency response curve to better reflect signals in frequency bands below the resonant zero, thereby improving the frequency selectivity of the filter and the signal quality of the passive antenna placed above the filter.

[0069] In one possible implementation, the shapes of the metal segments of the first and second conductive patterns, as well as the gaps formed on the metal surface of the second surface, are not limited to straight lines. They can be combinations of at least one of a variety of shapes, such as U-shaped, T-shaped, X-shaped, and Y-shaped, etc. H-shaped, E-shaped, and F-shaped can be considered as combinations of T-shaped and / or L-shaped. Specifically, the shape of the third segment 330 shown in FIG3 can be considered as a combination of L-shaped and T-shaped, and the shape of the first segment 310 shown in FIG4 can be considered as U-shaped.

[0070] In one possible implementation, at least one of the first, second, or third conductive patterns is an axisymmetric and / or centrosymmetric pattern. Repeated arrangements of axisymmetric and / or centrosymmetric patterns can reduce design complexity and improve the frequency selectivity and effective bandwidth of the filter.

[0071] In some embodiments, the shielding cavity 230 includes a plurality of cavity segments 231 forming a second grid array, each second grid being surrounded by a number of cavity segments 231 of array elements; each cavity segment 231 is adjacent to a first frequency selection surface 210, and its projection on a second surface 212 of the adjacent first frequency selection surface 210 is located within a third region 263; at least one first frequency selection surface 210 includes a clearance region 250 located at a position in the third region 263 adjacent to a vertex of the first grid, the clearance region 250 clearances metal line segments on a first surface 211 and clearances gaps 242 on a second surface 212; the clearance region 250 is used for cavity segments 231 to pass through in order to connect with other cavity segments 231 to form a second grid.

[0072] It should be understood that the avoidance area 250 and the third area 263 are different areas. The avoidance area 250 is used for the cavity segment 231 to pass through, while the third area is used for mounting the cavity segment 231 on the first frequency selection surface. They have different functions, and the avoidance area is not part of the third area. For example, in this embodiment, the avoidance area 250 is an area formed by cutting, grooving, or other processes between the first area and the second area.

[0073] In this implementation, the antenna array feed network can be set up in the shielded cavity first, and then the first frequency selection surface can be set on the shielded cavity to manufacture the filter device, which is beneficial to improving the manufacturing efficiency of the filter device.

[0074] In one possible implementation, the edge of the avoidance region 250 is attached to the outer surface of the cavity segment 231. Specifically, Figure 3(a) shows one cavity segment 231 of the shielding cavity 230, and Figure 3(b) shows a schematic diagram of a second side structure, where the height of the avoidance region 250 is substantially the same as the height of the cavity segment, and of course, the cross-sectional area of ​​the cavity segment (not shown in the figure) is also substantially the same as the cross-sectional area of ​​the avoidance region 250. Furthermore, as shown in Figure 2, the avoidance region 250 does not eliminate any part of the first conductive pattern 241, and as shown in Figure 3, the avoidance region 250 does not eliminate any part of the gap 242 of the second conductive pattern.

[0075] In some embodiments, FIG5 shows a schematic diagram of a shielding cavity 230. For clarity, the top of the shielding cavity is not shown. The shielding cavity 230 includes multiple cavity segments 231, which serve as edges of a frame and are connected to vertices 232 of the frame. The first frequency selection surface 210 shown in FIG3(b) is placed vertically into the rectangular gap formed by the shielding cavity. Then, while rotating the first frequency selection surface about the z-axis, a cavity segment 231 is inserted along the opening direction of the clearance region 250, thus completing the assembly of a first frequency selection surface 210 and a shielding cavity 230. Repeating the above steps multiple times completes the assembly of all first frequency selection surfaces in a filter unit. It should be understood that the vertex 232 of the frame is a part of the cavity segment 231, and multiple cavity segments 231 adjacent to a vertex 232 share that vertex.

[0076] In one possible implementation, the first frequency selection surface and the shielding cavity can be more securely connected by welding, crimping, or other methods to complete the installation of the first frequency selection surface and the shielding cavity.

[0077] In one possible implementation, the length, width, height, and groove depth of the cavity segments within the shielding cavity can be set in a computerized numerical control (CNC) bending machine. Subsequently, a sheet metal bending process is performed to manufacture a shielding cavity of suitable dimensions. To improve the utilization rate of the metal sheet and simplify processing, the shielding cavity, excluding the top, can be manufactured first using sheet metal bending. Then, the power supply network is placed, and finally, the individual top section is welded or press-fitted onto the uncovered cavity to complete the manufacturing of the entire shielding cavity.

[0078] In this implementation, when the first frequency selection surface is installed on the shielding cavity, multiple first frequency selection surfaces can be arranged regularly and neatly, so that the filter device has a simple structure of periodic repetition, which is beneficial to improving the manufacturing efficiency of the filter device.

[0079] In some embodiments, the frequency response performance of the filter device implementing all the preferred embodiments described above is tested to obtain the frequency response curve of the filter device. As shown in Figure 6, Figure 6(a) shows the frequency response curve of the filter device in TE mode, and Figure 6(b) shows the frequency response curve of the filter device in TM mode. Due to the introduction of the resonant zero of the first conductive pattern, the frequency response curve achieves a rapid roll-off of the transmission coefficient in a very narrow transition frequency band, with a roll-off rate of approximately 220 dB / GHz. With a reference of a transmission coefficient greater than -1 dB, the bandwidth of the filter device provided in this application can reach approximately 50% of the entire frequency band.

[0080] In some embodiments, FIG7 illustrates that adjusting the pattern size of the first conductive pattern can change the cutoff frequency of the filter device. Specifically, changing the opening width g of the first and second non-closed regions shown in FIG7(a) can change the value of the resonant zero, thereby changing the shape of the frequency response curve shown in FIG7(b).

[0081] In some embodiments, FIG8 illustrates that adjusting the size of the slits in the second conductive pattern can change the bandwidth of the filter device. Specifically, changing the opening width w of the third segment 330 and the fourth segment 340 shown in FIG8(a) can change the bandwidth characteristics, thereby changing the shape of the frequency response curve shown in FIG8(b).

[0082] In some embodiments, the first frequency selection surface is snapped onto the cavity segment by a first edge and a second edge of the avoidance region, the first edge being perpendicular to the second edge. Specifically, Figure 9(a) shows a portion of a filtering unit 200, which includes a plurality of first frequency selection surfaces provided with avoidance regions 250. Each first frequency selection surface 210 includes a first edge 251 and a second edge 252 that are perpendicular to each other, and the area formed by the first edge 251 and the second edge 252 is the avoidance region 250. Figure 9(b) shows a schematic diagram of the structure of a second surface 212, which more clearly shows the avoidance region 250 and the first edge 251 and the second edge 252.

[0083] It should be understood that each first frequency selection surface in the filter unit shown in Figure 9(a) is provided with an electrical connection component 270 at its upper and lower ends, such as a welded metal plate or other conductor, to realize the electrical connection between the metal surface of the second side of one first frequency selection surface and the metal surface of the second side of another first frequency selection surface. That is to say, the specific shape of the first frequency selection surface only affects the way they are electrically connected. In various embodiments of this application, each first frequency selection surface in the filter unit array is electrically connected.

[0084] For ease of explanation, setting the avoidance area shown in Figure 9 is equivalent to setting a through groove on the basis of setting the avoidance area shown in Figure 3. The through groove is located next to the first area 261 or the second area 262. Therefore, setting the avoidance area shown in Figure 3 can be called not setting a through groove or not opening a through groove, while setting the avoidance area shown in Figure 9 can be called setting a through groove or opening a through groove.

[0085] In one possible implementation, the first edges of the two avoidance regions adjacent to a vertex of the first grid are located on opposite sides of the shielding cavity. Specifically, by inserting the avoidance region 250 of the first frequency selection surface shown in Figure 9(b) directly into a cavity segment 231 along the through-slot direction in a vertical direction, the assembly of a first frequency selection surface 210 and a cavity segment 231 can be completed. One first frequency selection surface is inserted into the shielding cavity from top to bottom, and the adjacent first frequency selection surface is inserted into the shielding cavity from bottom to top. By repeating the above steps multiple times, the assembly of all first frequency selection surfaces in a filter unit can be completed.

[0086] In some embodiments, the frequency response performance of a filter device formed by a filter unit with a through slot is tested to obtain the frequency response curve of the filter device. Figure 10 shows the frequency response curves of a filter device with a first frequency selective surface having a blind slot as shown in Figure 3 and a filter device with a first frequency selective surface having a through slot as shown in Figure 9 in TE mode. It can be seen that setting a clearance area in the form of a through slot on the first frequency selective surface has little impact on the electromagnetic characteristics of the filter unit.

[0087] In this implementation, when the first frequency selective surface is installed on the shielded cavity, there is a large gap between adjacent first frequency selective surfaces. This facilitates installation without reducing frequency selectivity and helps improve the manufacturing efficiency of the filter device.

[0088] In some embodiments, according to the structural schematic diagram of the filter unit shown in FIG11, the filter unit array includes a plurality of hexagonal filter units 400 arranged in close proximity. Each filter unit 400 includes six first frequency selection surfaces 410, and each first frequency selection surface 410 is provided with a first conductive pattern 441. The first non-closed region and the second non-closed region of the first conductive pattern 441 are rectangular in shape. Of course, the cross-section of the filter unit can also be other common polygons that can be arranged in close proximity, such as rhombuses or isosceles trapezoids. This application does not limit the cross-sectional shape of the filter unit.

[0089] It should be understood that when the filter unit array is in the form of a hexagonal grid, the shielding cavity array is also in the form of a hexagonal grid. In other words, the shapes of the first grid and the second grid have a corresponding relationship.

[0090] This application also provides a base station antenna, which includes any of the filtering devices provided in the foregoing embodiments and multiple antenna arrays. The filtering device has a shielding cavity containing a feed network for the antenna arrays, and the multiple antenna arrays are respectively disposed on both sides of the filtering device. In some embodiments, FIG12 shows a base station antenna, which, from bottom to top, sequentially comprises at least one multiple-input multiple-output (MIMO) antenna array 510, a filtering device 100 provided in any embodiment of this application, and at least one mid-to-low frequency dipole antenna 520. The MIMO antenna array is an active antenna array, and the mid-to-low frequency dipole antenna array is a passive antenna array. Typically, the filtering device has a shielding cavity containing a feed network for the passive antenna array.

[0091] In one possible implementation, multiple antenna arrays located on one side of the filtering device operate in multiple operating frequency bands. For example, as shown in FIG12, the base station antenna below the filtering device 100 may include multiple MIMO antenna arrays operating in different operating frequency bands, and the radio frequency signals transmitted by these multiple MIMO antenna arrays may come from radio frequency modules operating in different operating frequency bands.

[0092] This application also provides a base station device, which includes the base station antenna provided in the foregoing embodiments, and a power supply for supplying power to the base station antenna.

[0093] It should be noted that, in the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in this article is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0094] In the embodiments of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more, and "at least one" and "one or more" refer to one, two, or more than two. The singular expressions "a," "an," "the," "the," "this," and "this" are intended to also include expressions such as "one or more," unless the context explicitly indicates otherwise.

[0095] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0096] In the description of the embodiments of this application, the terms "upper," "lower," "inner," "outer," "vertical," and "horizontal," etc., indicate orientations or positional relationships relative to the indicated placement of components in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and not to indicate or imply a specific orientation that the device or component must have, or its construction and operation in a specific orientation. They can change accordingly depending on the orientation of the components in the accompanying drawings, and therefore should not be construed as limiting this application. Furthermore, "vertical" in this application is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0097] In this application, the same reference numerals are used to denote the same components. For the same components in this application, only one component may be labeled with a reference numeral in the figures. It should be understood that the reference numerals also apply to other identical components. Furthermore, for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. In addition, the components in the figures are not drawn to actual scale, and the dimensions and sizes of the components shown in the figures are merely exemplary and should not be construed as limiting this application.

[0098] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0099] The above description is merely a specific embodiment 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. A filtering device, characterized in that, The system includes a first frequency selective surface (210) and a shielding cavity (230). The first frequency selective surface (210) includes a first surface (211) and a second surface (212) opposite to each other. The first surface (211) is provided with a first conductive pattern (241) formed by metal line segments, and the second surface (212) is provided with a second conductive pattern formed by gaps (242) on the metal surface. The second surface includes a first region (261), a second region (262), and a third region (263) between the first region (261) and the second region (262). The first region (261) and the second region (262) are provided with the gaps (242). The projection of the shielding cavity (230) on the second surface (212) is located in the third region (263). The shielding cavity (230) is used to set up a power supply network.

2. The filtering device according to claim 1, characterized in that, The first conductive pattern (241) includes a first line segment (310) and a second line segment (320). The first line segment (310) forms a first non-closed region, and the second line segment (320) is located inside the first non-closed region and forms a second non-closed region. There is a gap between the first line segment (310) and the second line segment (320). The opening direction of the first non-closed region is opposite to the opening direction of the second non-closed region.

3. The filtering device according to claim 1 or 2, characterized in that, The number of the first frequency selection surfaces (210) is multiple, each of the first frequency selection surfaces (210) intersects with the first plane, and the multiple first frequency selection surfaces (210) are configured to be arranged in the first plane to form a first grid array, each of the first grids being surrounded by the number of array elements of the first frequency selection surfaces (210).

4. The filtering device according to claim 3, characterized in that, The shielding cavity (230) includes a plurality of cavity segments (231) forming a second grid array, each second grid being surrounded by the number of cavity segments (231) of the array elements; each cavity segment (231) is adjacent to a first frequency selection surface (210), and its projection on the second surface (212) of the adjacent first frequency selection surface (210) is located within the third region (263); At least one of the first frequency selection surfaces (210) includes a clearance region (250) located at a position adjacent to the vertex of the first grid in the third region (263), the clearance region (250) clearances the metal line segment on the first surface (211) and the gap (242) on the second surface (212); the clearance region (250) is used for the cavity segment (231) to pass through in order to connect with other cavity segments (231) to form the second grid.

5. The filtering device according to claim 4, characterized in that, The edge of the avoidance area (250) is attached to the outer surface of the cavity segment (231).

6. The filtering device according to claim 4 or 5, characterized in that, The first frequency selection surface (210) is engaged with the cavity segment (231) by the first edge (251) and the second edge (252) of the avoidance area (250), wherein the first edge (251) is perpendicular to the second edge (252).

7. The filtering device according to claim 6, characterized in that, The first edges (251) of the two avoidance regions (250) adjacent to a vertex of the first grid are located on both sides of the shielding cavity (230).

8. The filtering device according to any one of claims 4 to 7, characterized in that, The first grid and the second grid are polygonal grids.

9. The filtering device according to any one of claims 1 to 8, characterized in that, The filtering device further includes at least one second frequency selection surface (120) perpendicular to the first frequency selection surface (210), and the second frequency selection surface (120) is provided with a third conductive pattern (130).

10. The filtering device according to claim 9, characterized in that, At least one of the first conductive pattern (241), the second conductive pattern, or the third conductive pattern (130) is an axisymmetric pattern and / or a centrally symmetric pattern.

11. A base station antenna, characterized in that, The filter includes a filter device as described in any one of claims 1 to 10, and a plurality of antenna arrays, wherein a feed network for the antenna arrays is provided inside the shielding cavity (230) of the filter device, and the plurality of antenna arrays are respectively disposed on both sides of the filter device.

12. The base station antenna according to claim 11, characterized in that, Multiple antenna arrays located on one side of the filtering device operate in multiple frequency bands.

13. A base station device, characterized in that, It includes a base station antenna as described in claim 11 or 12, and a power supply for supplying power to the base station antenna.

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