Frequency selective surface structure for 5G base station and filtering antenna array thereof

Abstract

The invention relates to the technical field of communication, in particular to a frequency selective surface structure for a 5G base station and a filtering antenna array of the frequency selective surface structure. The frequency selective surface structure for the 5G base station comprises at least one filtering unit, the filtering unit is in a sheet shape, and the filtering unit comprises an external metal layer, a dielectric substrate, a middle metal layer, another dielectric substrate and another external metal layer which are stacked in sequence; the outer metal layer comprises a plurality of first metal sheets, the first metal sheets are arranged in a square array, the first metal sheets are square metal sheets, aperture windows are formed in the middles of the first metal sheets, gap grooves are formed in the four faces of each first metal sheet, and the aperture windows and the gap grooves are separated through bent connecting parts. According to the frequency selective surface structure for the 5G base station, the requirement of a 5G Massive MIMO antenna base station for a filter in a radio frequency channel can be effectively released, and the frequency selective surface structure has the advantages of being low in loss, wide in scanning angle, good in directional diagram conformality, simple in structure and low in implementation cost.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a frequency selective surface structure and a filtering antenna array thereof for a 5G base station. Background Art

[0002] Massive MIMO (Massive Multiple Input Multiple Output) technology is an important method to improve the spectrum utilization and channel capacity of communication systems. With the popularization of 5G communication, its application scope is becoming wider and wider. Different from the connection method between antennas and RRU units (remote radio units) in 2 / 3 / 4G base stations through RF feeders, when high-frequency networking is performed in 5G Massive MIMO systems, the number of antenna units and RF channels increases sharply. At the same time, in order to meet the needs of beamforming, the connection method between base station antennas and RRU units through feeders is no longer applicable. The RRU units and antenna arrays need to be combined into AAU units (active antenna units), such as Figure 1 Common AAU units, such as 64T64R or 32T32R, have significantly more RF channels than traditional base stations. Based on the traditional base station filtering solution, each channel is independently cascaded with a bandpass filter to filter the guided wave, as shown in Figure 1. Figure 2 As shown, the number of RF filters required for Massive MIMO base stations will become too large, which is not conducive to the miniaturization and cost control of AAU units.

[0003] The bandpass frequency selective surface (FSS) is a periodic filtering structure that allows spatial electromagnetic waves within a specific frequency range to pass through while shielding other frequencies. It has the advantages of light weight, small size, and easy integration, and can be widely used in antenna arrays, radomes and other fields. Existing bandpass frequency selective surfaces (FSS) mainly include:

[0004] (1) Bandpass frequency selective surfaces based on non-resonant electrical small units can obtain high-order bandpass responses by cascading two or more non-resonant miniaturized elements. However, as the filter order increases, the structural cross-section and insertion loss will increase, and it is difficult to achieve double-sideband transmission zeros.

[0005] (2) The three-dimensional bandpass frequency selective surface has the advantage of being able to achieve frequency selection characteristics comparable to those of traditional cavity filters, but its disadvantage is that the structure is complex and difficult to assemble and process.

[0006] (3) Bandpass frequency selective surfaces based on the principle of slot-coupled resonance, which combine the advantages of high selectivity and easy processing and assembly, have double-sideband transmission zeros, and have good elevation and polarization stability. However, their unit size is usually larger than a quarter wavelength, and their azimuth stability is poor, making them unsuitable for direct application in 5G massive MIMO antenna arrays for pre-filtering. Summary of the invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0008] To this end, the present invention provides a frequency selective surface structure and a filtering antenna array for a 5G base station, which can effectively release the demand for filters in the RF channel of the 5G Massive MIMO base station, and has low loss, wide scanning angle, good conformal properties of the radiation pattern, simple structure and low implementation cost.

[0009] A frequency selective surface structure for a 5G base station according to an embodiment of the present invention includes:

[0010] At least one filter unit, the filter unit is in a sheet shape, and the filter unit includes

[0011] An outer metal layer, a dielectric substrate, an intermediate metal layer, another dielectric substrate and another outer metal layer are sequentially stacked;

[0012] The external metal layer includes a plurality of first metal sheets, which are arranged in a square array. The first metal sheets are square metal sheets, an aperture window is provided in the middle of the first metal sheet, and slit grooves are provided on four surfaces of the first metal sheet. The aperture window and the slit grooves are separated by a bent connection portion.

[0013] The beneficial effect of the present invention is that the frequency selective surface structure for 5G base stations of the present invention reduces the unit size of the filter unit through structural improvement, improves the angle stability, and has good polarization stability due to the miniaturization of the filter unit size and the rotational symmetry. In addition, it has a double-sideband transmission zero point and good filtering performance, and can be better applied to the filtering scenario of 5G large-scale MIMO base station antennas.

[0014] According to one embodiment of the present invention, the side of the bent connecting portion facing the aperture window is formed with a bridge section, two connecting sections and two corner sections, one end of the bridge section is connected to one of the connecting sections through one of the corner sections, the other end of the bridge section is connected to another of the connecting sections through another of the corner sections, the angle between the corner section and the bridge section is 135°, and the angle between the corner section and the connecting section is 135°.

[0015] According to one embodiment of the present invention, the width W between the bridge section and the corresponding bottom of the slot is 1 =0.75mm, the length of the bridge section is greater than the width of the slit groove.

[0016] According to one embodiment of the present invention, the aperture window is an X-shaped hole, the four corners of the aperture window are right angles, and the right angle side L of the right angle is 3 =1.4mm.

[0017] According to one embodiment of the present invention, the depth L of the slot is 2 =4.1mm, and the width of the slit groove g=1.25mm.

[0018] According to an embodiment of the present invention, the four slit grooves divide the first metal sheet into four sub-metal sheets, the bent connecting portion is used to connect two adjacent sub-metal sheets, and the width L of the sub-metal sheet is 1 =5.95mm.

[0019] According to one embodiment of the present invention, the intermediate metal layer includes a plurality of second metal sheets arranged in a square array, each of the four surfaces of the second metal sheets has a protrusion, and two adjacent second metal sheets are connected via two opposite protrusions.

[0020] According to one embodiment of the present invention, the width L of the second metal sheet is 4 =11.8mm, the width W of the protrusion 2 =1.4mm, and the protruding height of the protrusion is 1.1mm.

[0021] According to an embodiment of the present invention, the dielectric substrate has a thickness of 0.3 mm to 1 mm, a relative dielectric constant of 3.5, and a loss tangent of 0.002.

[0022] A filtering antenna array comprises the frequency selective surface structure for a 5G base station as described above, a reflecting plate and at least one antenna unit, wherein the frequency selective surface structure for the 5G base station is arranged in parallel on one side of the reflecting plate, and the antenna unit is installed on the side of the reflecting plate facing the frequency selective surface structure for the 5G base station.

[0023] According to an embodiment of the present invention, the antenna unit includes a first dipole unit and a second dipole unit, and the first dipole unit and the second dipole unit are both provided with slits, and the first dipole unit and the second dipole unit are welded and installed on the reflector in a vertically crossed state through the slits, and the end faces of the two are on the same horizontal line.

[0024] According to one embodiment of the present invention, the frequency selective surface structure for the 5G base station is located at a quarter wavelength directly above the antenna unit.

[0025] According to one embodiment of the present invention, each of the antenna units corresponds one-to-one to the filtering unit of the frequency selective surface structure for the 5G base station.

[0026] According to one embodiment of the present invention, the first dipole unit and the second dipole unit both include: a radiation dipole arm, a dielectric plate and a feeding balun, the radiation dipole arm is arranged on the front side of the dielectric plate, and the feeding balun is arranged on the back side of the dielectric plate.

[0027] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Figure 1 This is a schematic diagram of the existing AAU structure.

[0031] Figure 2 It is a schematic diagram of the 5G Massive MIMO base station RF front end based on the traditional filtering solution.

[0032] Figure 3 It is a structural diagram of embodiment 1 of the present invention.

[0033] Figure 4 It is a schematic diagram of the explosion of the first embodiment of the present invention.

[0034] Figure 5 It is a schematic diagram of a first metal sheet according to the first embodiment of the present invention.

[0035] Figure 6 This is a schematic diagram of the size identification of the first metal sheet according to the first embodiment of the present invention.

[0036] Figure 7 It is a schematic diagram of the second metal sheet structure of the first embodiment of the present invention.

[0037] Figure 8 This is the electric field and magnetic field distribution diagram of the surface of the bending connection unit under the plane wave normal incidence excitation of the first embodiment of the present invention, (a) electric field; (b) magnetic field distribution diagram.

[0038] Fig. 9 It is a schematic diagram of the subarray structure under the cell boundary of the first embodiment of the present invention.

[0039] Fig.10 1 is the transmission coefficient of the filter unit under different plane wave incident angles in the first embodiment of the present invention, (a) TE polarized wave; (b) TM polarized wave.

[0040] Fig.11 It is a structural diagram of embodiment 2 of the present invention.

[0041] Fig.12 It is a schematic diagram of the minimum filtering unit structure of the second embodiment of the present invention.

[0042] Fig.13 This is a comparison result of the transmission coefficients of the minimum filter unit in the second embodiment of the present invention.

[0043] Fig.14 It is a schematic diagram of the improved 5G Massive MIMO base station radio frequency front end according to the second embodiment of the present invention.

[0044] In the figure: 1, filter unit; 11, external metal layer; 12, dielectric substrate; 13, intermediate metal layer; 111, first metal sheet; 112, aperture window; 113, slot; 114, bent connecting portion; 115, sub-metal sheet; 1141, bridge section; 1142, connecting section; 1143, corner section; 131, second metal sheet; 132, protruding portion;

[0045] 2. Antenna unit; 21. First dipole unit; 22. Second dipole unit; 221. Dielectric plate; 222. Radiation dipole arm; 223. Feed balun;

[0046] 3. Reflector;

[0047] 4. Selective surface structure. DETAILED DESCRIPTION

[0048] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0049] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] Example 1

[0052] The present application embodiment provides a frequency selective surface structure for a 5G base station, such as Figure 3-9 As shown, including:

[0053] At least one filter unit 1, the filter unit 1 is in a sheet shape, and the filter unit 1 includes:

[0054] An outer metal layer 11, a dielectric substrate 12, an intermediate metal layer 13, another dielectric substrate 12 and another outer metal layer 11 are stacked in sequence;

[0055] The outer metal layer 11 includes a plurality of first metal sheets 111, which are arranged in a square array. The first metal sheet 111 is a square metal sheet, an aperture window 112 is provided in the middle of the first metal sheet 111, and slit grooves 113 are provided on the four surfaces of the first metal sheet 111. The aperture window 112 and the slit grooves 113 are separated by a bent connection portion 114. The provided bent connection portion 114 can obtain larger equivalent capacitance and equivalent inductance parameters, effectively reducing the unit size of the filter unit, and realizing the miniaturization of the frequency selective surface structure for 5G base stations.

[0056] It should be noted that when the two outer metal layers 11 resonate through the aperture window 112 under the irradiation of the plane electromagnetic wave, the surface electric field and magnetic field distribution are shown in FIG. Fig. 9 As shown, for an incident plane wave with TE polarization (polarized in the y direction), the surface electric field is mainly concentrated on the edge of the outer metal layer 11 in the x direction. At the same time, the magnetic field distribution is mainly divided into two parts, most of the magnetic field is distributed in the bent connection portion 114; a small part of the magnetic field is distributed on the side wall of the slot 113.

[0057] In the embodiment, the side of the bent connecting portion 114 facing the aperture window 112 is formed with a bridge section 1141, two connecting sections 1142 and two corner sections 1143, one end of the bridge section 1141 is connected to one connecting section 1142 through a corner section 1143, the other end of the bridge section 1141 is connected to another connecting section 1142 through another corner section 1143, the angle between the corner section 1143 and the bridge section 1141 is 135°, and the angle between the corner section 1143 and the connecting section 1142 is 135°. Further, the width W between the bridge section 1141 and the bottom of the corresponding slot 113 is 135°. 1 =0.75 mm, the length of the bridge section 1141 is greater than the width of the slot 113 .

[0058] In the embodiment, the aperture window 112 is an X-shaped hole, and the four corners of the aperture window 112 are right angles, and the right angle side L of the right angle is 3 =1.4mm.

[0059] In the embodiment, the depth L of the slot 113 is 2 =4.1mm, the width g of the slit groove 113 =1.25mm.

[0060] In the embodiment, the four slots 113 divide the first metal sheet 111 into four sub-metal sheets 115. The bent connecting portion 114 is used to connect two adjacent sub-metal sheets 115. The width L of the sub-metal sheet 115 is 1 =5.95mm.

[0061] In an embodiment, the intermediate metal layer 13 includes a plurality of second metal sheets 131, and the plurality of second metal sheets 131 are arranged in a square array. The four surfaces of the second metal sheets 131 have protrusions 132, and two adjacent second metal sheets 131 are connected by two relative protrusions 132 to ensure that the frequency selective surface structure used for the 5G base station has sufficient electric coupling strength and magnetic coupling strength, thereby obtaining a double-sideband transmission zero point, thereby improving the passband filtering performance.

[0062] In the embodiment, the width L of the second metal sheet 131 is 4 =11.8 mm, the width W of the protrusion 132 2=1.4 mm, and the protruding height of the protrusion 132 is 1.1 mm.

[0063] In the embodiment, the outer metal layer 11 and the middle metal layer 13 are made of the same material, and are formed by copper plating on the dielectric substrate 12. The thickness of the outer metal layer 11 and the middle metal layer 13 are both 0.035 mm. The first metal sheet 111 and the second metal sheet 131 have the same size, which is a, and a=14 mm.

[0064] In the embodiment, the dielectric substrate 12 has a thickness of 0.3 mm to 1 mm, a relative dielectric constant of 3.5, a loss tangent of 0.002, and is made of a F4BM series plate. In a specific implementation, the dielectric substrate 12 has a thickness of 0.5 mm and is made of F4BM350.

[0065] In practical applications, the plurality of first metal sheets 111 and the plurality of second metal sheets 131 are distributed in an N*M array to form a square array, and the unit size of a sub-array is 0.16λ. 0 ×0.16λ 0 ×0.01λ 0 For example, if the size of an antenna unit of the base station is 56*56 mm, since the first metal sheet 111 and the second metal sheet 131 have the same size, a=14, and N and M are both set to 4. Figure 4 As shown, a minimum filtering unit (MEFSS) is formed, that is, one antenna unit is matched with one filtering unit. For another example, when the antenna unit size is 42*70mm, N is set to 3, M is set to 5, and the number of the first metal sheet 111 and the second metal sheet is set according to the actual antenna unit size.

[0066] Fig. 9 The relative spatial position of a subarray of filter elements under the boundary of the CST2018 cell is shown, and the simulation software is used to simulate the model parameters. Fig. 9 The filter unit is used to obtain the calculation results. The calculation results can be found in Fig.10 As shown, thanks to miniaturization and rotational symmetry, the polarization stability and angle stability are good. Therefore, under the oblique incidence of TE and TM polarized waves in the range of arbitrary azimuth angle φ and elevation angle θ of 0 to 60°, the frequency selective surface structure used for 5G base stations has a 3dB common transmission bandwidth of 110MHz (3.46 to 3.57GHz) and good transmission performance.

[0067] The frequency selective surface structure for 5G base stations of the present invention reduces the unit size of the filter unit through structural improvement, improves the angle stability, and has good polarization stability due to the miniaturization of the filter unit size and the rotational symmetry. In addition, it has a double-sideband transmission zero point and good filtering performance, and can be better applied to the filtering scenario of 5G large-scale MIMO base station antennas.

[0068] Example 2

[0069] The present application embodiment provides a filtering antenna array, Figure 11-14 As shown, it includes the above-mentioned frequency selective surface structure 4 for a 5G base station, a reflecting plate 3 and at least one antenna unit 2. The frequency selective surface structure 4 for the 5G base station is arranged in parallel on one side of the reflecting plate 3, and the antenna unit 2 is installed on the side of the reflecting plate 3 facing the frequency selective surface structure 4 for the 5G base station.

[0070] In the embodiment, the antenna unit 2 includes a first dipole unit 21 and a second dipole unit 22, and the first dipole unit 21 and the second dipole unit 22 are both provided with slit grooves, and the first dipole unit 21 and the second dipole unit 22 are welded and installed on the reflector 3 in a vertical cross state through the slit grooves, and the end faces of the two are on the same horizontal line.

[0071] In an embodiment, the frequency selective surface structure 4 for a 5G base station is located at a quarter wavelength directly above the antenna unit 2 .

[0072] In the embodiment, each antenna unit 2 corresponds one-to-one to a filter unit of the frequency selective surface structure 4 for a 5G base station. In other words, one antenna unit corresponds to one filter unit.

[0073] In the embodiment, the first dipole unit 21 and the second dipole unit 22 both include: a radiation dipole arm 222, a dielectric plate 221, and a feeding balun 223, wherein the radiation dipole arm 222 is arranged on the front side of the dielectric plate 221, and the feeding balun 223 is arranged on the back side of the dielectric plate 221. The feeding balun 223 can adopt a microstrip structure to realize impedance conversion and field matching, thereby realizing impedance matching of the antenna, and facilitating the integration of the antenna.

[0074] Taking the minimum filter unit as an example, Fig.13 The minimum unit calculation results of the filtering antenna array under the CST2018 cell boundary are shown. Compared with the prior art, after loading the filtering unit, the maximum in-band transmission loss of the antenna array of this embodiment is 0.6dB, and the upper and lower sidebands are significantly suppressed, among which the upper and lower sidebands (3~3.4GHz&3.8~4.2GHz) are suppressed by ≥10dB, and the lower sideband (3.95~4.2GHz) is suppressed by ≥20dB.

[0075] In this embodiment, if Fig.14 As shown, by placing the frequency selective surface structure 4 for the 5G base station in front of the base station antenna array and pre-filtering the spatial electromagnetic waves received / radiated by the base station antenna, the demand for the 5G Massive MIMO antenna array for the RF channel filter can be effectively released, which has low loss, wide scanning angle, good conformal properties of the radiation pattern, simple structure and low implementation cost.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0077] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A frequency selective surface structure for a 5G base station, characterized in that: include: At least one filter unit (1), the filter unit (1) is in the form of a sheet, and the filter unit (1) comprises An outer metal layer (11), a dielectric substrate (12), an intermediate metal layer (13), another dielectric substrate (12) and another outer metal layer (11) are stacked in sequence; The external metal layer (11) comprises a plurality of first metal sheets (111), the plurality of first metal sheets (111) being arranged in a square array, the first metal sheets (111) being square metal sheets, an aperture window (112) being provided in the middle of the first metal sheet (111), slit grooves (113) being provided on four surfaces of the first metal sheet (111), and the aperture window (112) and the slit grooves (113) being separated by a bent connection portion (114).

2. The frequency selective surface structure for a 5G base station according to claim 1, characterized in that: The side of the bent connecting portion (114) facing the aperture window (112) is formed with a bridge section (1141), two connecting sections (1142) and two corner sections (1143); one end of the bridge section (1141) is connected to one of the connecting sections (1142) via one of the corner sections (1143); the other end of the bridge section (1141) is connected to another of the connecting sections (1142) via another of the corner sections (1143); the included angle between the corner section (1143) and the bridge section (1141) is 135°; and the included angle between the corner section (1143) and the connecting section (1142) is 135°.

3. The frequency selective surface structure for a 5G base station according to claim 2, characterized in that: The width W1 between the bridge section (1141) and the bottom of the corresponding slit groove (113) is 0.75 mm, and the length of the bridge section (1141) is greater than the width of the slit groove (113).

4. The frequency selective surface structure for a 5G base station according to claim 1, characterized in that: The aperture window (112) is an X-shaped hole, and the four corners of the aperture window (112) are right angles, and the right angle side L3 of the right angle is 1.4 mm.

5. The frequency selective surface structure for a 5G base station according to claim 1, characterized in that: The depth L2 of the slit groove (113) is 4.1 mm, and the width g of the slit groove (113) is 1.25 mm.

6. The frequency selective surface structure for a 5G base station according to claim 1, characterized in that: The four slit grooves (113) divide the first metal sheet (111) into four sub-metal sheets (115); the bent connection portion (114) is used to connect two adjacent sub-metal sheets (115); and the width L1 of the sub-metal sheet (115) is 5.95 mm.

7. The frequency selective surface structure for a 5G base station according to claim 1, characterized in that: The intermediate metal layer (13) comprises a plurality of second metal sheets (131), wherein the plurality of second metal sheets (131) are arranged in a square array, each of the four surfaces of the second metal sheet (131) has a protrusion (132), and two adjacent second metal sheets (131) are connected via two opposite protrusions (132).

8. The frequency selective surface structure for a 5G base station according to claim 7, characterized in that: The width L4 of the second metal sheet (131) is 11.8 mm, the width W2 of the protruding portion (132) is 1.4 mm, and the protruding height of the protruding portion (132) is 1.1 mm.

9. The frequency selective surface structure for a 5G base station according to claim 1, characterized in that: The dielectric substrate (12) has a thickness of 0.3 mm to 1 mm, a relative dielectric constant of 3.5, and a loss tangent of 0.

002.

10. A filtering antenna array, characterized in that: It comprises a frequency selective surface structure (4) for a 5G base station as described in any one of claims 1 to 9, a reflecting plate (3) and at least one antenna unit (2), wherein the frequency selective surface structure (4) for the 5G base station is arranged in parallel on one side of the reflecting plate (3), and the antenna unit (2) is installed on the side of the reflecting plate (3) facing the frequency selective surface structure (4) for the 5G base station.

11. The filtering antenna array according to claim 10, characterized in that: The antenna unit (2) comprises a first dipole unit (21) and a second dipole unit (22), wherein the first dipole unit (21) and the second dipole unit (22) are both provided with slits, and the first dipole unit (21) and the second dipole unit (22) are welded and mounted on the reflector (3) in a vertically crossed state through the slits, and the end faces of the two are on the same horizontal line.

12. The filtering antenna array according to claim 10, characterized in that: The frequency selective surface structure (4) for the 5G base station is located at a quarter wavelength directly above the antenna unit (2).

13. The filtering antenna array according to claim 12, characterized in that: Each of the antenna units (2) corresponds one-to-one to a filtering unit of the frequency selective surface structure (4) for a 5G base station.

14. The filtering antenna array according to claim 11, characterized in that: The first dipole unit (21) and the second dipole unit (22) both comprise: a radiation dipole arm (222), a dielectric plate (221) and a feeding balun (223); the radiation dipole arm (222) is arranged on the front side of the dielectric plate (221), and the feeding balun (223) is arranged on the back side of the dielectric plate (221).

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