Antenna unit, array antenna, and network device

Abstract

Embodiments of the present application provide an antenna unit, an array antenna, and a network device. The antenna unit comprises: a first dielectric substrate, which is provided with a plurality of radiation elements distributed in a rectangular array, the plurality of radiation elements having gaps therebetween; a metal floor layer, which is provided with a plurality of coupling gaps, the plurality of coupling gaps respectively corresponding to edges of the rectangular array, and orthographic projections of the plurality of coupling gaps on the first dielectric substrate at least partially overlapping orthographic projections of the plurality of radiation elements on the first dielectric substrate; and a second dielectric substrate, which is provided with a feeding unit, the feeding unit being coupled to at least one of the plurality of coupling gaps. The first dielectric substrate, the metal floor layer, and the second dielectric substrate are sequentially stacked. The plurality of radiation units are arranged on the surface of the first dielectric substrate facing away from the metal floor layer. The feeding unit is arranged on the surface of the second dielectric substrate facing away from the metal floor layer.

Description

Antenna unit, array antenna and network device

[0001] Cross-reference to related applications

[0002] This application claims priority to the Chinese patent application No. 202411389482.4, filed on September 30, 2024, and entitled "Antenna unit, array antenna and network device", the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of communication devices, in particular to an antenna unit, an array antenna and a network device. BACKGROUND

[0004] A dual linearly polarized antenna has two orthogonal linear polarization modes, and two ports of the same antenna unit are used for excitation. The dual linearly polarized antenna can realize polarization diversity, and compared with a conventional tilt dipole antenna, the antenna unit with two orthogonal ports can provide lower output correlation and higher diversity gain. Therefore, the dual linearly polarized antenna is widely used in the field of wireless communication. SUMMARY

[0005] The present application provides an antenna unit, an array antenna and a network device.

[0006] The antenna unit provided by the present application embodiment comprises a first dielectric substrate, a metal ground plate layer and a second dielectric substrate. The first dielectric substrate is provided with a plurality of radiation units arranged in a rectangular array, and the plurality of radiation units have gaps therebetween. The metal ground plate layer is provided with a plurality of coupling gaps, and the plurality of coupling gaps correspond to the edges of the rectangular array respectively. The plurality of coupling gaps and the plurality of radiation units at least partially overlap in orthographic projection on the first dielectric substrate. The second dielectric substrate is provided with a feed unit, and the feed unit is coupled to at least one of the plurality of coupling gaps. The first dielectric substrate, the metal ground plate layer and the second dielectric substrate are sequentially stacked. The plurality of radiation units are arranged on the surface of the first dielectric substrate away from the metal ground plate layer. The feed unit is arranged on the surface of the third dielectric substrate away from the metal ground plate layer.

[0007] In this scheme, there is a potential difference on both sides of the gap between the two adjacent radiation units, which can be equivalent to a capacitor. Dividing a whole radiation patch into small patches (i.e., radiation units) can change the current distribution and improve the isolation of the two orthogonal excitation source ports, thereby solving the problem of poor isolation of the two orthogonal excitation source ports of the dual linearly polarized antenna.

[0008] In an embodiment, the plurality of radiating elements comprises four first radiating elements arranged in a rectangular array, and a plurality of second radiating element groups, each of the second radiating element groups comprises at least one second radiating element, and each of the second radiating element groups is arranged between every two first radiating elements in the rectangular array.

[0009] In an embodiment, the at least one second radiating element is rectangular, and a side length of each of the first radiating elements is greater than a short side of the at least one second radiating element.

[0010] In the embodiment, the patches at the four corners are designed to be larger, on one hand, to provide sufficient design space for the feeding structure, and on the other hand, to increase the radiation area at the gap-coupled feeding points, thereby improving the antenna gain.

[0011] A size of each of the second radiating element groups in an extension direction of each side of the rectangular array is a constant value.

[0012] In an embodiment, the at least one second radiating element comprises two second radiating elements, and an arrangement direction of the two second radiating elements is the same as an arrangement direction of the corresponding two first radiating elements.

[0013] In an embodiment, each of the second radiating element groups corresponds to one of the coupling gaps.

[0014] In an embodiment, orthographic projections of the plurality of coupling gaps on the first dielectric substrate respectively overlap orthographic projections of the plurality of second radiating element groups on the first dielectric substrate.

[0015] In an embodiment, the plurality of radiating elements further comprises four third radiating elements arranged at a middle portion of a surface of the first dielectric substrate facing away from the second dielectric substrate, and the first radiating elements, the second radiating element groups, and the third radiating elements are arranged in the rectangular array.

[0016] In an embodiment, each of the first radiating elements is square, each of the third radiating elements is square, and a side length ratio of the first radiating elements to the third radiating elements is 1.8:1.

[0017] In an embodiment, a side length of the first radiating elements is 10.6 millimeters, and a side length of the third radiating elements is 5.8 millimeters.

[0018] In an embodiment, the plurality of radiating elements are rectangular in shape, and preferably, the plurality of radiating elements are square in shape with the same side length.

[0019] In an embodiment, the number of the plurality of radiating elements is four.

[0020] In an embodiment, the plurality of radiating elements and the plurality of coupling slots are in a periodic structure.

[0021] In an embodiment, the plurality of coupling slots comprises a first pair of coupling slots and a second pair of coupling slots, the coupling slots of the two pairs of coupling slots are respectively arranged opposite to each other, the feeding elements comprise a first feeding element and a second feeding element, the first feeding element is respectively coupled to the first pair of coupling slots, and the second feeding element is respectively coupled to the second pair of coupling slots.

[0022] In an embodiment, the power distribution ratio of the first feeding element and the second feeding element is 1:1.

[0023] In an embodiment, the first feeding element comprises a first power distribution structure, the first power distribution structure comprises a first input section and two first output sections, the first input section is used to be connected with a first feeding network, and the two first output sections are used to be coupled to the first pair of coupling slots; and

[0024] the second feeding element comprises a second power distribution structure, the second power distribution structure comprises a second input section and two second output sections, the second input section is used to be connected with a second feeding network, and the two second output sections are used to be coupled to the second pair of coupling slots.

[0025] In an embodiment, the first power distribution structure further comprises two first quarter-wavelength transformers, the two first quarter-wavelength transformers are respectively connected to the first input section close to one end of the first output section, the two first output sections are respectively connected to the first input section through the two first quarter-wavelength transformers, so that the first input section and the two first output sections are impedance matched; and / or

[0026] the second power distribution structure further comprises a second quarter-wavelength transformer, the second quarter-wavelength transformer is connected to the second input section close to one end of the second output section, and the two second output sections are respectively connected to the second input section through the second quarter-wavelength transformer, so that the second input section and the two second output sections are impedance matched.

[0027] In an embodiment, the first output section is respectively connected with a fan-shaped stub away from one end of the first input section; and / or

[0028] the second output section is respectively connected with a fan-shaped stub away from one end of the second input section.

[0029] In an embodiment, the radius of the fan-shaped branch is 0.1-0.2 times the wavelength of the waveguide, and the opening angle of the fan-shaped branch is 90-120°.

[0030] The application further provides an array antenna, which comprises a feed network and a plurality of the antenna units as described above, the plurality of antenna units are arranged in an array, and the feed network is coupled to the feed units of the antenna units.

[0031] The array antenna comprises the antenna units as described above, and thus can achieve the technical effects of the antenna units, i.e., there is a potential difference on both sides of the gap between two adjacent radiation units, which can be equivalent to a capacitor. Dividing a whole radiation patch into a plurality of small patches (i.e., radiation units) can change the current distribution and improve the isolation of two orthogonal excitation source ports.

[0032] In an embodiment, the feed network comprises a first feed network and a second feed network, the first feed network is coupled to the first feed units of the antenna units, and the second feed network is coupled to the second feed units of the antenna units.

[0033] In an embodiment, the array antenna comprises eight antenna units, and the eight antenna units are arranged in a one-dimensional line.

[0034] In an embodiment, the distance between the centers of two adjacent antenna units in the arrangement direction of the eight antenna units is 0.5-1 times the wavelength of the array antenna.

[0035] In the embodiment, a larger gain can be obtained at the distance, and the grating lobes can be avoided.

[0036] In an embodiment, the first feed network comprises four first output ends, each of the first output ends is connected to two adjacent first feed units through a 1:2 power divider; and the second feed network comprises four second output ends, each of the second output ends is connected to two adjacent second feed units through a 1:2 power divider.

[0037] In an embodiment, each of the two outputs of the 1-to-2 power divider includes a microstrip line; the width of each of the two outputs of the 1-to-2 power divider is determined based on the power ratio of the first feeding units and the power ratio of the second feeding units, so as to reduce the side lobe level of the radiation pattern of the array antenna and reduce the difference between the gains of the two polarizations of the array antenna. For example, the power ratio of the first feeding units along the arrangement direction of the antenna units is 0.385:0.5:0.769:1:1:0.769:0.5:0.385, and the power ratio of the second feeding units along the arrangement direction of the antenna units is 0.267:0.427:0.667:1:1:0.667:0.427:0.267. The feeding network of the array antenna adopts a non-equal-amplitude and in-phase parallel feeding structure, and by reasonably controlling the power distributed to each radiation unit, the side lobe level can be suppressed.

[0038] In an embodiment, the array antenna includes a reflecting plate, each of the radiation units is located on the side of the first dielectric substrate away from the reflecting plate, the distance between the second dielectric substrate and the reflecting plate is a quarter of a wavelength, and each of the antenna units is fixed to the reflecting plate through the second dielectric substrate.

[0039] In this scheme, the arrangement of the reflecting plate can improve the front-to-back ratio of the array antenna and reduce the side lobe level at the horizontal angle, and the distance between the second dielectric substrate and the reflecting plate is a quarter of a wavelength, so that the electric field reflected by the reflecting plate can be superimposed with the electric field not reflected by the reflecting plate, thereby improving the signal radiation ability of the array antenna.

[0040] The embodiments of the present application also provide a network device, which includes any one of the antenna units provided in the technical solutions above, and the network device can at least achieve the technical effects of the antenna unit, which will not be repeated here.

[0041] The embodiments of the present application also provide a network device, which includes any one of the array antennas provided in the technical solutions above, and the network device can at least achieve the technical effects of the array antenna, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0043] FIG. 1a is a structural schematic diagram of an antenna unit provided in an embodiment of the present application.

[0044] Fig. 1b is a front view of the antenna unit shown in Fig. 1a.

[0045] Fig. 2 is an exploded view of the antenna unit shown in Fig. 1a.

[0046] Fig. 3 is a structural schematic diagram of another antenna unit provided by an embodiment of the present application.

[0047] Fig. 4 is a simulation diagram of current distribution of a conventional microstrip patch antenna.

[0048] Fig. 5 is a simulation diagram of current distribution of an antenna unit provided by an embodiment of the present application.

[0049] Fig. 6 is a simulation diagram of current distribution of another antenna unit provided by an embodiment of the present application.

[0050] Fig. 7 is a reflection phase characteristic diagram of the antenna unit C and the antenna unit D.

[0051] Fig. 8a is a diagram of current distribution of the antenna unit C at 5.24 GHz.

[0052] Fig. 8b is a diagram of current distribution of the antenna unit C at 6.02 GHz.

[0053] Fig. 9a is a diagram of current distribution of the antenna unit D at 5.24 GHz.

[0054] Fig. 9b is a diagram of current distribution of the antenna unit D at 6.02 GHz.

[0055] Fig. 10 is a comparison diagram of unilateral feeding and bilateral feeding patterns.

[0056] Fig. 11 is a structural schematic diagram of a first feeding unit and a second feeding unit in an antenna unit provided by an embodiment of the present application.

[0057] Fig. 12 is a front view of an array antenna provided by an embodiment of the present application.

[0058] Fig. 13a is a front view of another array antenna provided by an embodiment of the present application.

[0059] Fig. 13b is a structural schematic diagram of the array antenna shown in Fig. 13a.

[0060] Fig. 14 is a front view of a first feeding network, a second feeding network, and a first feeding unit and a second feeding unit in an array antenna provided by an embodiment of the present application.

[0061] Fig. 15a is a simulation diagram of port isolation of the array antenna shown in Fig. 12.

[0062] Fig. 15b is a simulation diagram of port isolation of the array antenna shown in Fig. 13a.

[0063] Figure 16a is a vertical polarization pattern of the array antenna shown in Figure 12.

[0064] Figure 16b is a horizontal polarization pattern of the array antenna shown in Figure 12.

[0065] Figure 16c is a simulation plot of gain versus frequency of the array antenna shown in Figure 12.

[0066] Figure 17a is a vertical polarization pattern of the array antenna shown in Figure 13a.

[0067] Figure 17b is a horizontal polarization pattern of the array antenna shown in Figure 13a.

[0068] Figure 17c is a simulation plot of gain versus frequency of the array antenna shown in Figure 13a.

[0069] Figure 18a is a return loss simulation plot of the array antenna shown in Figure 12.

[0070] Figure 18b is a return loss simulation plot of the array antenna shown in Figure 13a.

[0071] Figure Legend: 1 - first dielectric substrate; 2 - metal ground plane layer; 21 - coupling slot; 3 - second dielectric substrate; 41 - first radiating element; 42 - second radiating element; 43 - third radiating element; 5 - first feed element; 6 - second feed element; 7 - first power dividing structure; 71 - first input section; 72 - first output section; 8 - second power dividing structure; 81 - second input section; 82 - second output section; 91 - first quarter wave transformer; 92 - second quarter wave transformer; 73 - sectorized stub; 100 - first feed network; 200 - second feed network. DETAILED DESCRIPTION

[0072] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0073] The terms "first", "second" are only used for description purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specified.

[0074] In the related art, due to non-ideal electromagnetic crosstalk effect and other factors, the isolation of two orthogonal excitation source ports is poor when the dual-linear polarization antenna is applied, which affects the anti-interference ability of the entire communication system.

[0075] The various exemplary embodiments of the present application provide an antenna unit, an array antenna and a network device.

[0076] FIG. 1a is a structural schematic diagram of an antenna unit provided by an embodiment of the present application, FIG. 1b is a front view of the antenna unit shown in FIG. 1a, and FIG. 2 is an exploded view of the antenna unit shown in FIG. 1a. As shown in FIG. 1a, FIG. 1b and FIG. 2, the antenna unit includes a first dielectric substrate 1, a metal ground plane layer 2 and a second dielectric substrate 3 which are sequentially stacked. The antenna unit further includes a plurality of radiation units 41, 42 arranged on the surface of the first dielectric substrate 1 away from the second dielectric substrate 3, and a first feeding unit 5 and a second feeding unit 6 arranged on the surface of the second dielectric substrate 3 away from the first dielectric substrate 1. In the embodiment, the plurality of radiation units 41, 42 can include four first radiation units 41 and four second radiation unit groups which are distributed in a rectangular array. One second radiation unit group can be arranged between every two adjacent first radiation units 41, and each second radiation unit group can include at least one second radiation unit 42 (two are shown in the figure). Adjacent two radiation units 41, 42 have a gap therebetween. In this way, the plurality of radiation units 41, 42 are distributed in a rectangular array on the surface of the first dielectric substrate 1 away from the second dielectric substrate 3. In the embodiment, the middle part of the surface of the first dielectric substrate 1 away from the second dielectric substrate 3 (i.e. the middle part of the rectangular array) is not provided with radiation units. It can be understood that in other embodiments, radiation units can also be arranged in a rectangular array in the middle part of the rectangular array. Exemplarily, the radiation units can be metal radiation patches.

[0077] In the above embodiment, in each of the radiation units 41, 42 in the same row of the rectangular array, the size of the first radiation unit 41 along the length of the side of the rectangular array is greater than the size of the second radiation unit 42 along the length of the side of the rectangular array. For example, referring to FIG. 1a, along the length of the side a of the rectangular array, the first radiation unit A1, the second radiation unit B1, the second radiation unit B2, and the first radiation unit A2 are arranged in sequence. The lengths of the first radiation unit A1, the second radiation unit B1, the second radiation unit B2, and the first radiation unit A2 along the length of the side a of the rectangular array are d1, d2, d3, and d4, respectively, where d1 and d4 are greater than d2 and d3. Similarly, along the length of the side b of the rectangular array, the first radiation unit A2, the second radiation unit B3, the second radiation unit B4, and the first radiation unit A3 are arranged in sequence. The lengths of the first radiation unit A2, the second radiation unit B3, the second radiation unit B4, and the first radiation unit A3 along the length of the side b of the rectangular array are d5, d6, d7, and d8, respectively, where d5 and d8 are greater than d6 and d7.

[0078] Next, referring to FIG. 1b and FIG. 2, the metal ground layer 2 has coupling slots 21, and each second radiation unit group corresponds to one coupling slot 21. The first feed unit 5 is used to be coupled to one group of coupling slots 21 arranged opposite to each other. The second feed unit 6 is used to be coupled to another group of coupling slots 21 arranged opposite to each other. For example, in the view angle shown in FIG. 1b, the first feed unit 5 is used to be coupled to two coupling slots 21 arranged left and right, and the second feed unit 6 is used to be coupled to two coupling slots 21 arranged up and down.

[0079] In this scheme, there is a potential difference between the two sides of the gap between the two adjacent radiation units 41, 42, which can be equivalent to a capacitor. By dividing a whole metal radiation patch into multiple small radiation patches (i.e., radiation units) of non-uniform sizes and adjusting the gap width between two adjacent radiation units, the current distribution can be changed, and the isolation of the two orthogonal excitation source ports can be improved. In addition, the area of the radiation unit at the corner (i.e., the first radiation unit) is larger. In this way, on the one hand, the feed units 5, 6 have sufficient design space, and on the other hand, the radiation area at the gap coupling feed point is increased, which can improve the antenna gain.

[0080] The first dielectric substrate 1 serves as a carrier for the radiation units 41, 42, and when selecting the material, the impact on the antenna bandwidth and the cost factor need to be considered. For example, in order to save costs, the first dielectric substrate 1 can be made of a flame-retardant material with a flame-retardant level of FR4, or a dielectric substrate with a lower dielectric constant can be used to achieve the design goal of a large bandwidth. In this application, the first dielectric substrate 1 is taken as an example of a flame-retardant material with a flame-retardant level of FR4.

[0081] The second dielectric substrate 3 and the first dielectric substrate 1 can be made of the same material according to actual needs, or can be made of dielectric substrates with different electrical parameters. The loss of the feed network affects the radiation efficiency of the antenna, therefore, the second dielectric substrate 3 is made of a low-loss plate. Exemplarily, the tangent value tanδ of the second dielectric substrate 3 is 0.0009-0.006. The first dielectric substrate 1, the metal floor layer 2 and the second dielectric substrate 3 can be connected by a mixed pressing process. The metal floor layer 2 can be a copper-coated metal floor, and the metal floor layer 2 can be one layer or two layers. It is not difficult to understand that when the metal floor layer 2 is two layers, the two layers of the metal floor layer 2 are stacked. Exemplarily, when the metal floor layer 2 is two layers, the coupling slots 21 of the two layers of the metal floor layer 2 are coincident in the orthographic projection on the first dielectric substrate 1.

[0082] When the antenna unit is working, the radio frequency energy enters the feed unit through the antenna ports 5, 6, and when passing through the coupling slots 21, the electromagnetic energy is transmitted to the radiation units 41, 42 by aperture coupling, and then the energy is radiated to the space by the radiation units 41, 42.

[0083] When designing the antenna unit, the length and width of the antenna unit are preliminarily determined according to the working wavelength of the antenna, so that after the first radiation unit 41 is determined, the size of the second radiation unit group on the long side and the short side of the rectangular array is also determined as a constant value. That is, the sum of the sizes of the second radiation units on the same side of the rectangular array is a constant value.

[0084] Please continue to refer to FIG. 1b, the second radiation unit group includes two second radiation units 42, and the arrangement direction of the two second radiation units 42 is the same as that of the two first radiation units 41 adjacent to the second radiation unit group. The extension direction of the coupling slot 21 is perpendicular to the extension direction of the gap between the two second radiation units 42 corresponding to the coupling slot 21, and the orthographic projection of the coupling slot 21 on the first dielectric substrate 1 and the orthographic projection of the two second radiation units 42 corresponding to the coupling slot 21 on the first dielectric substrate 1 both have overlaps.

[0085] Of course, in other implementations, the second radiation unit group can also include one second radiation unit 42. In this case, the extending direction of the coupling slot 21 is the same as the arrangement direction of the two first radiation units 41 adjacent to the second radiation unit 42, and the orthogonal projection of the coupling slot 21 on the first dielectric substrate 1 overlaps with the orthogonal projection of the second radiation unit 42 on the first dielectric substrate 1. The second radiation unit group can also include more than two second radiation units 42, and the arrangement direction of each second radiation unit 42 is the same as the arrangement direction of the two first radiation units 41 adjacent to the second radiation unit group. The extending direction of the coupling slot 21 is perpendicular to the extending direction of the slot between the second radiation unit 42 corresponding to the coupling slot 21, and the orthogonal projection of the coupling slot 21 on the first dielectric substrate 1 overlaps with the orthogonal projection of each second radiation unit 42 corresponding to the coupling slot 21 on the first dielectric substrate 1.

[0086] The size of the second radiation unit group on the same side of the rectangular array is a constant value. For example, the second radiation unit group includes one second radiation unit 42. The arrangement direction of the two first radiation units 41 adjacent to the second radiation unit 42 is the first direction. The extending direction of the side of the rectangular array perpendicular to the first direction is the second direction, the size of the second radiation unit 42 in the first direction is W2, and the size of the second radiation unit 42 in the second direction is W2. In another embodiment, the second radiation unit group includes two second radiation units 42, and the arrangement direction of the two second radiation units 42 is the same as the arrangement direction of the two first radiation units 41 adjacent to the second radiation unit group. The arrangement direction of the two first radiation units 41 adjacent to the second radiation unit group is the first direction, the extending direction of the side of the rectangular array perpendicular to the first direction is the second direction, the sum of the sizes of the second radiation units 42 in the first direction is W11, and the size of the second radiation units 42 in the second direction is W22. Then W11=W1 and W22=W2. That is, in the first direction, the more the number of second radiation units 42 in the second radiation unit group, the smaller the size of each second radiation unit 42 in the first direction. It is worth noting that W11 is the size of the second radiation unit group in the first direction, which can include the sum of the sizes of the second radiation units 42 in the first direction and the size of the slot between the adjacent two second radiation units 42 in the first direction.

[0087] Figure 3 is a structural schematic diagram of another antenna unit provided by an embodiment of the present application. As shown in Figure 3, on the basis of the embodiments shown in Figures la, lb and c, the plurality of radiation units 41, 42, 43 further include four third radiation units 43 arranged in the middle of the surface of the first dielectric substrate 1 facing away from the second dielectric substrate 3, and the four third radiation units 43 are arranged in a rectangular array. The first radiation units 41 and the second radiation units 42 are arranged around the outer periphery of the four third radiation units 43, and any adjacent pair of third radiation units 43 and the two second radiation units 42 located on the two sides thereof are located on the same straight line.

[0088] Exemplarily, the third radiation unit 43 can be a complete metal radiation patch, or can be further divided into a plurality of sub-radiation units. In one specific implementation, the third radiation unit 43 can include four sub-radiation units arranged in a rectangular array, and in another specific implementation, the third radiation unit 43 can include two equally divided sub-radiation units. In the embodiments of the present application, a complete metal radiation patch is taken as an example for description of each third radiation unit 43.

[0089] Next, the current distribution of a conventional microstrip patch antenna and the current distribution of the antenna unit provided by each exemplary embodiment of the present application are compared and described. Figure 4 is a simulation diagram of the current distribution of a conventional microstrip patch antenna, wherein the larger the arrow, the greater the current. As shown in Figure 4, the simulation result shows that the conventional microstrip patch antenna (one radiation unit) has strong radiation current distribution at the four coupling slots 41, and the current is transmitted to the other polarization port through the feed unit, causing deterioration of the isolation.

[0090] Figure 5 is a simulation diagram of the current distribution of an antenna unit provided by an embodiment of the present application, and Figure 6 is a simulation diagram of the current distribution of another antenna unit provided by an embodiment of the present application. By adjusting the size ratio of each radiation unit, the degree of freedom of antenna design can be increased, such as in the antenna unit corresponding to Figure 6, the radiation units are divided into three different sizes. In order to make the radiation area at each coupling slot 21 as large as possible, the area of each radiation unit 41, 42 located at the periphery is greater than the area of each radiation unit 43 located in the middle. The current is mainly concentrated in the two rows of radiation units, i.e. the two rows including the first radiation units 41, and the current at the two coupling slots 21 of the middle row is further reduced. In this scheme, by reducing the current distribution at the coupling slot 21 corresponding to one of the orthogonal excitation source ports, high isolation between the two orthogonal excitation source ports is achieved.

[0091] In the antenna unit corresponding to FIG. 6, the middle four radiation units 43 have almost no current distribution. Therefore, the antenna unit corresponding to FIG. 6 can remove the middle radiation units and be simplified as the antenna unit corresponding to FIG. 5. The current distribution of the antenna unit corresponding to FIG. 6 is consistent with the current distribution of the antenna unit corresponding to FIG. 5, the bandwidth characteristics and the radiation characteristics are similar, and in the antenna unit corresponding to FIG. 5, the current at the coupling gap 21 corresponding to the left and right two columns of radiation units is further reduced. Both the antenna unit corresponding to FIG. 5 and the antenna unit corresponding to FIG. 6 can meet the communication requirements of the WLAN 5G frequency band.

[0092] For ease of description, hereinafter, the antenna unit corresponding to FIG. 5 is taken as an antenna unit C, and the antenna unit corresponding to FIG. 6 is taken as an antenna unit D.

[0093] The periodic structure of the above-mentioned antenna units also has metasurface characteristics. FIG. 7 is a reflection phase characteristic diagram of the antenna unit C and the antenna unit D, wherein the curve located on the upper side represents the reflection phase characteristic of the antenna unit D, and the curve located on the lower side represents the reflection phase characteristic of the antenna unit C. It can be observed from FIG. 7 that the reflection phase characteristics of the two are close. Therefore, they have similar radiation characteristics. The antenna unit C and the antenna unit D have a reflection phase of 0 degrees near 5.6 GHz and 5.5 GHz, respectively, and exhibit metasurface characteristics at the frequency points.

[0094] FIG. 8a and FIG. 8b respectively show the current distribution of the antenna unit C at 5.24 GHz and 6.02 GHz, and FIG. 9a and FIG. 9b respectively show the current distribution of the antenna unit D at 5.24 GHz and 6.02 GHz. It can be seen from FIG. 8a, FIG. 8b, FIG. 9a and FIG. 9b that the two frequency points work in different resonance modes respectively. By introducing multi-mode, the antenna excites more resonance modes, increases the resonance points of the antenna, and thus improves the bandwidth of the antenna. In addition, it can be seen that the current modes of the above-mentioned two antenna units are similar, and therefore, their bandwidth characteristics and radiation characteristics are also similar, and the antenna unit C does not cause a decrease in the performance of the antenna.

[0095] Please continue to refer to FIG. 9b, the pattern formed by the radiation units 41, 42, and 43 is a central symmetric pattern, the pattern formed by the coupling slots 21 is also a central symmetric pattern, and the symmetry center of the pattern formed by the coupling slots 21 coincides with the symmetry center of the pattern formed by the radiation units. Thus, the two orthogonal polarizations can have similar radiation performance. In addition, please refer to the comparison chart of the single-sided feeding and double-sided feeding patterns shown in FIG. 10, where the curve m1 represents the double-sided feeding pattern, and the curve m2 represents the single-sided feeding pattern. The antenna unit feeds the metasurface radiation patch through two symmetric coupling slots 21, compared with the single-sided feeding mode, the double-sided feeding can increase the maximum gain of the antenna from 5.7dBi to 7.8dBi, and can avoid the pattern deviation problem caused by single-sided feeding, and the front gain can be increased by 3dBi. Compared with the traditional probe feeding or side feeding, the antenna unit can further improve the bandwidth of the antenna, and reduce the spurious radiation caused by the feeding network, and can ensure the directivity of the antenna radiation.

[0096] In specific implementation, the first radiation unit 41 and the third radiation unit 43 can both be square, and the length ratio of the first radiation unit 41 to the third radiation unit 43 can be 1.8:1. For example, the length of the first radiation unit 41 is 10.6 mm, and the length of the third radiation unit 43 is 5.8 mm. Exemplarily, the width of the slot between any two adjacent radiation units is 1 mm, the width of the coupling slot 21 is 1 mm, and the length of the coupling slot 21 is 9 mm.

[0097] In some embodiments, the power distribution ratio of the first feeding unit 5 and the second feeding unit 6 is both 1:1, that is, the antenna unit internally adopts a differential feeding structure with equal amplitudes.

[0098] Please refer to the structure diagram of the first feeding unit 5 and the second feeding unit 6 shown in FIG. 11. The first feeding unit 5 includes a first power distribution structure 7, the first power distribution structure 7 includes a first input section 71 and two first output sections 72, the first input section 71 is used for connecting with the feeding network, and the two first output sections 72 are used for coupling connection with a set of opposite coupling slots. The difference between the lengths of the two first output sections 72 is half of the waveguide wavelength, so that the current phase difference of the two coupling slots 21 coupled with the two first output sections 72 is 180°. The second feeding unit 6 includes a second power distribution structure 8, the second power distribution structure 8 includes a second input section 81 and two second output sections 82, the second input section 81 is used for connecting with the feeding network, and the two second output sections 82 are used for coupling connection with another set of opposite coupling slots 21. The difference between the lengths of the two second output sections 82 is half of the waveguide wavelength, so that the current phase difference of the two coupling slots 21 coupled with the two second output sections 82 is 180°. Exemplarily, the difference between the lengths of the two first output sections 72 can be 16.5mm, and the difference between the lengths of the two second output sections 82 can also be 16.5mm. It is worth noting that the difference between the lengths of the two output sections in the same power distribution structure being half of the waveguide wavelength is not a strict limitation, and it can be approximately half of the waveguide wavelength.

[0099] Please continue to refer to FIG. 11, the first power distribution structure 7 can include two first quarter-wave transformers 91. The two first quarter-wave transformers 91 can be connected with the first input section 71 near one end of the first output section 72, and the two first output sections 72 can be connected with the first input section 71 through one first quarter-wave transformer 91 respectively, so as to match the impedance of the first input section 71 and the two first output sections 72.

[0100] The second power distribution structure 8 can include one second quarter-wave transformer 92. The second quarter-wave transformer 92 can be connected with the second input section 81 near one end of the second output section 82, and the two second output sections 82 can be connected with the second input section 81 through the second quarter-wave transformer 92 respectively, so as to match the impedance of the second input section 81 and the two second output sections 82.

[0101] This scheme can avoid the need for via design due to wiring, and improve the reliability of the structure. Exemplarily, the first power distribution structure 7 realizes impedance matching and equal-amplitude power distribution through a first quarter-wave transformer 91 with an impedance value of 71Ω. The second power distribution structure 8 realizes impedance matching by using two second quarter-wave transformers 92 with an impedance value of 35Ω. By using the above two power distribution structures, the area of the feeding network can be reduced, and the coupling between the two feeding units can be reduced, preventing the deterioration of port isolation.

[0102] Since the first feeding unit 5 and the second feeding unit 6 comprise microstrip lines, there is an impedance discontinuity from the microstrip line to the coupling slot 21. In some embodiments, as shown in FIG. 11, a fan-shaped stub 73 is connected to the end of the first output segment 72 away from the first input segment 71 and the end of the second output segment 82 away from the second input segment 81. By adjusting the radius and angle of the fan-shaped stub, the end of the coupling slot 21 and the corresponding first feeding unit 5 or second feeding unit 6 form a resonance, so that the impedance discontinuity of the coupling slot 21 to the microstrip line is bridged, thereby improving the impedance matching within the bandwidth.

[0103] The design of the fan-shaped stub 73 at the end of the feeding unit 5, 6, with a radius smaller than the matching scheme using 1 / 4 wavelength stubs, can reduce the coupling between the first feeding unit 5 and the second feeding unit 6. Exemplarily, the radius r of the fan-shaped stub 73 is 0.1-0.2 times the waveguide wavelength, and the spread angle of the fan-shaped stub 73 is 90-120°.

[0104] FIG. 12 is a front view of an array antenna according to an embodiment of the present application, FIG. 13a is a front view of another array antenna according to an embodiment of the present application, and FIG. 13b is a perspective view of the array antenna shown in FIG. 13a. The embodiments shown in FIG. 12 and the embodiments shown in FIG. 13a and FIG. 13b have the same features in that the array antennas each comprise a first feeding network 100, a second feeding network 200, and a plurality of the above-described antenna units. The plurality of antenna units are arranged in an array, the first feeding network 100 is electrically connected to each first feeding unit 5, and the second feeding network 200 is electrically connected to each second feeding unit 6. It is not difficult to understand that in specific implementation, the first dielectric substrate 1 of each antenna unit can be integrally formed, the second dielectric substrate 3 of each antenna unit can be integrally formed, and the metal ground plane layer 2 of each antenna unit can be integrally formed. The array antenna provided by the present embodiment can be applied to a multi-MIMO network bridge device, but is not limited to a multi-MIMO network bridge device.

[0105] The embodiments shown in FIG. 12 and the embodiments shown in FIG. 13a and FIG. 13b differ in that the array antenna shown in FIG. 12 adopts the antenna unit shown in FIG. 3, and the array antennas shown in FIG. 13a and FIG. 13b adopt the antenna unit shown in FIG. 1a.

[0106] In specific implementation, the first feeding unit 5, the second feeding unit 6, the first feeding network 100, and the second feeding network 200 are integrally formed, for example, the first feeding network 100 and the second feeding network 200 are also microstrip lines, and the first feeding unit 5, the second feeding unit 6, the first feeding network 100, and the second feeding network 200 are prepared in the same layer by etching process.

[0107] Exemplarily, the array antenna can include eight antenna units arranged in one dimension linearly. In the arrangement direction of the antenna units, the distance between the centers of two adjacent antenna units is 0.5-1 times the array antenna wavelength. Exemplarily, the distance between the centers of two adjacent antenna units is 0.8 times the array antenna wavelength.

[0108] The antenna units are combined into an array antenna according to design requirements such as gain size, beam width, etc. In order to realize the regulation of the antenna pattern, the antenna units are connected to each other through a non-equal-amplitude feed network. By adjusting the width of the microstrip line of each stage of the feed network, accurate power distribution control can be realized. By reasonably controlling the power size distributed to each antenna unit, the sidelobe level of the radiation pattern can be effectively reduced.

[0109] The two array antennas shown in FIGS. 12 and 13a can adopt a consistent feed network structure. Due to the difference in the superposition effect of one-dimensional linear arrays on different polarized electric fields, the gains of the two polarized array antennas are inconsistent, and therefore, a feed network with different power distribution ratios needs to be designed for the two polarized ports to reduce the difference in gain. According to the Chebyshev array theory: T m (x) = cos(m x arccos x), -1 ≤ x ≤ 1 T m (x) = ch(m x arch x), x > 1 T m (x) = (-1) m ch(m x arch x), x < -1

[0110] The sidelobe level preset value can determine the initial power ratio of the plurality of first feed units and the initial power ratio of the plurality of second feed units; and then in combination with the gain size and the beam width of the array antenna, the final power ratio of the plurality of first feed units and the final power ratio of the plurality of second feed units are optimized and determined.

[0111] Exemplarily, the two output ends of the one-to-two power divider each include a microstrip line. The width of the two output ends of each one-to-two power divider is determined based on the power ratio of the plurality of first feed units 5 and the power ratio of the plurality of second feed units 6, so as to reduce the sidelobe level of the radiation pattern of the array antenna and reduce the difference between the gains of the two polarizations of the array antenna.

[0112] Since the antenna gains of the two polarization ports are inconsistent, the first feed network 100 and the second feed network 200 adopt different power distribution ratios. Please refer to the front view of the first feed network 100, the second feed network 200, the first feed unit 5 and the second feed unit 6 shown in FIG. 14. The eight first feed units 5 and the eight second feed units 6 are arranged from left to right, the first feed network 100 includes four first output ends F1, each first output end F1 is connected with two adjacent first feed units 5 through a 1:2 power divider; along the arrangement direction of the antenna units, the power ratio of each first feed unit 5 (that is, the end power distribution ratio of the first feed network 100) is: 0.385:0.5:0.769:1:1:0.769:0.5:0.385; the second feed network 200 includes four second output ends F2, each second output end F2 is connected with two adjacent second feed units 6 through a 1:2 power divider; along the arrangement direction of the antenna units, the power ratio of each second feed unit 6 (that is, the end power distribution ratio of the second feed network 200) is: 0.267:0.427:0.667:1:1:0.667:0.427:0.267. That is, P1:P2:P3:P4:P5:P6:P7:P8=0.385:0.5:0.769:1:1:0.769:0.5:0.385, P1’:P2’:P3’:P4’:P5’:P6’:P7’:P8’=0.267:0.427:0.667:1:1:0.667:0.427:0.267. The end power distribution ratio of the first feed network 100 and the end power distribution ratio of the second feed network 200 are both symmetrically distributed. The antenna units are connected and combined into an array antenna through the non-equal-amplitude feed network, the distance between the centers of two adjacent antenna units is: 0.8×c / central frequency of the array antenna working, under this spacing, a larger gain can be obtained, and the generation of grating lobes can be avoided. In addition, the feed network of the array antenna adopts a non-equal-amplitude and in-phase parallel feeding structure, by reasonably controlling the power size distributed to each radiation unit, the suppression of the sidelobe level can be realized.

[0113] Please continue to refer to FIG. 14, in a specific implementation, the first feeding network 100 and the second feeding network 200 can each include a first-stage 1:2 power divider E1, two second-stage 1:2 power dividers E2, and four third-stage 1:2 power dividers E3, two outputs of the first-stage 1:2 power divider E1 are respectively connected to one of the second-stage 1:2 power dividers E2, two outputs of each of the second-stage 1:2 power dividers E2 are respectively connected to one of the third-stage 1:2 power dividers E3, and two outputs of each of the third-stage 1:2 power dividers E3 are respectively connected to one of the feeding units. The power ratio of the first-stage 1:2 power divider E1 of the first feeding network 100 and the second feeding network 200 is 1:1, the power ratio of each of the two second-stage 1:2 power dividers E2 of the first feeding network 100 is 1:2, and the power ratio of each of the four third-stage 1:2 power dividers E3 of the first feeding network 100 is 1:1.3. The power ratio of each of the two second-stage 1:2 power dividers E2 of the second feeding network 200 is 1:2.5, the power ratio of the first and third third-stage 1:2 power dividers E3 from left to right of the second feeding network 200 is 1:1.6, and the power ratio of the second and fourth third-stage 1:2 power dividers E3 of the second feeding network 200 is 1:1.5.

[0114] Since the feeding network structure is in parallel, the currents at each frequency point have the same phase when reaching the output end, so that the shift of the radiation pattern can be avoided. The feeding structure between each adjacent two radiation units of the second feeding network 200 is mirror arranged, which can reduce the length of the feeding network and thus reduce the attenuation. In addition, the mirror arrangement does not change the phase difference at the upper and lower coupling slots 21 and does not affect the radiation characteristics.

[0115] In some embodiments, the array antenna includes a reflector plate, each antenna unit is fixed to the reflector plate, and each radiation unit is located on the side of the first dielectric substrate 1 away from the reflector plate, and the distance between the second dielectric substrate and the reflector plate is one quarter of a wavelength. In this scheme, the arrangement of the reflector plate can improve the front-to-back ratio of the array antenna and reduce the sidelobe level at the horizontal angle, and the distance between the second dielectric substrate and the reflector plate is one quarter of a wavelength, so that the electric field reflected by the reflector plate can be superimposed with the electric field not reflected by the reflector plate, thereby improving the signal radiation ability of the array antenna. Exemplarily, the second dielectric substrate can be fixed to the reflector plate by a support. It should be noted that the distance between the second dielectric substrate and the reflector plate is one quarter of a wavelength, which is not strictly limited, and in a specific implementation, the distance between the second dielectric substrate and the reflector plate can also be approximately one quarter of a wavelength.

[0116] Next, the technical effects that can be achieved by the array antenna provided in the embodiments of the present application are described in detail.

[0117] Fig. 15a shows a simulation diagram of port isolation of the array antenna shown in Fig. 12, and Fig. 15b shows a simulation diagram of port isolation of the array antenna shown in Fig. 13a. As shown in Fig. 15a and Fig. 15b, the dual-polarized array antenna has high isolation by designing a novel periodic microstrip structure. In the WLAN frequency band of 5.15 GHz-5.85 GHz, the isolation of the two polarization ports of the array antenna shown in Fig. 12 is more than 44.9 dB, and the isolation of the array antenna shown in Fig. 13a is better than 46.1 dB. The isolation of the array antenna shown in Fig. 13a is slightly higher than that of the array antenna shown in Fig. 12, which is due to the lower current distribution of the array antenna shown in Fig. 13a at the coupling slot 21 corresponding to the other polarization. Both of them are much better than the 25 dB of the traditional dual-polarized antenna, and meet the requirement that the isolation between the chip end and the antenna is greater than 30 dB.

[0118] Fig. 16a shows a vertical polarization pattern of the array antenna shown in Fig. 12, Fig. 16b shows a horizontal polarization pattern of the array antenna shown in Fig. 12, and Fig. 16c shows a simulation diagram of gain variation with frequency of the array antenna shown in Fig. 12. As shown in the figures, the maximum gains of the vertical polarization and the horizontal polarization of the array antenna shown in Fig. 12 are 16.4 dBi and 17.2 dBi respectively in the frequency band of 5.15 GHz-5.85 GHz, the gain fluctuations in the band are 0.3 dBi and 1.1 dBi respectively, and the maximum gain difference of the two polarizations is 0.8 dBi. By reasonably designing the non-equal-amplitude feeding network, the sidelobe level is reduced from -13.1 dB to -19.8 dB compared with the equal-amplitude feeding.

[0119] Fig. 17a shows a vertical polarization pattern of the array antenna shown in Fig. 13a, Fig. 17b shows a horizontal polarization pattern of the array antenna shown in Fig. 13a, and Fig. 17c shows a simulation diagram of gain variation with frequency of the array antenna shown in Fig. 13a. As shown in the figures, the maximum gains of the vertical polarization and the horizontal polarization of the array antenna shown in Fig. 13a are 16.6 dBi and 17.1 dBi respectively in the frequency band of 5.15 GHz-5.85 GHz, the gain fluctuations in the band are 0.5 dBi and 1.2 dBi respectively, and the maximum gain difference of the two polarizations is 0.6 dBi. The sidelobe level is -19.6 dB. It can be seen that the antenna unit shown in Fig. 13a and the antenna unit shown in Fig. 12 have similar radiation characteristics.

[0120] FIG. 18a shows a return loss simulation diagram of the array antenna shown in FIG. 12, and FIG. 18b shows a return loss simulation diagram of the array antenna shown in FIG. 13a. As can be seen from the diagrams, the dual-polarized array antenna generates three resonance points in the passband by introducing multi-modal radiation and slot-coupled feeding, and the three resonance points are close to each other to form a passband, thereby effectively improving the bandwidth of the array antenna. Among them, the relative bandwidth of the dual-polarized array antenna shown in FIG. 12 is 21.8%, and the relative bandwidth of the dual-polarized array antenna shown in FIG. 13a is 18.4%. The relative bandwidth of the dual-polarized array antenna shown in FIG. 13a is slightly lower than that of the dual-polarized array antenna shown in FIG. 12, and the lower frequency will be offset to a higher frequency. Both of them are better than the conventional microstrip antenna, and fully meet the communication requirements of the WLAN 5G frequency band.

[0121] In summary, the antenna provided by the embodiments of the present application adopts a multi-layer dielectric plate mixed pressure non-equiamplitude coupling feeding metasurface array method, which can improve the port isolation of the antenna (for example, a multi-MIMO antenna) and reduce the sidelobe level of the radiation pattern.

[0122] The embodiments of the present application also provide a network device including the array antenna described above, so at least the technical effects that can be achieved by the array antenna described above can be achieved, that is, the radiation area at the slot-coupled feeding point is increased, and the antenna gain can be improved.

[0123] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. An antenna unit, comprising: a first dielectric substrate provided with a plurality of radiating elements arranged in a rectangular array, the plurality of radiating elements having gaps therebetween; a metal ground plane layer provided with a plurality of coupling gaps, the plurality of coupling gaps corresponding to edges of the rectangular array respectively, and the plurality of coupling gaps having projections on the first dielectric substrate at least partially overlapping with projections of the plurality of radiating elements on the first dielectric substrate; and a second dielectric substrate provided with a feeding element coupled to at least one of the plurality of coupling gaps; wherein the first dielectric substrate, the metal ground plane layer and the second dielectric substrate are stacked in sequence, the plurality of radiating elements are arranged on a surface of the first dielectric substrate facing away from the metal ground plane layer, and the feeding element is arranged on a surface of the third dielectric substrate facing away from the metal ground plane layer. The plurality of radiating elements comprise: four first radiating elements arranged in a rectangular array; and 2. The antenna unit of claim 1, wherein, a plurality of second radiating element groups, each of the second radiating element groups comprising at least one second radiating element, and each of the second radiating element groups being arranged between every two first radiating elements in the rectangular array. The at least one second radiating element is rectangular, and a side length of each of the first radiating elements is greater than a short side of the at least one second radiating element. A dimension of the second radiating element groups in an extension direction of each edge of the rectangular array is a constant value.

3. The antenna unit of claim 2, wherein, The at least one second radiating element comprises two second radiating elements, and an arrangement direction of the two second radiating elements is the same as an arrangement direction of corresponding two first radiating elements.

4. The antenna unit according to claim 2 or 3, wherein, The second radiating element groups correspond to the coupling gaps one by one.

5. The antenna unit according to any one of claims 2 to 4, wherein, The projections of the plurality of coupling gaps on the first dielectric substrate overlap with the projections of the plurality of second radiating element groups on the first dielectric substrate respectively.

6. The antenna unit according to any one of claims 2 to 5, wherein, The plurality of radiating elements further comprise four third radiating elements arranged in a middle portion of a surface of the first dielectric substrate facing away from the second dielectric substrate, the first radiating elements, the second radiating element groups and the third radiating elements being arranged in the rectangular array.

7. The antenna unit according to any one of claims 2 to 6, wherein, Each of the first radiating elements is square, each of the third radiating elements is square, and a side length ratio of the first radiating elements to the third radiating elements is 1.8:1, preferably, a side length of the first radiating elements is 10.6 millimeters, and a side length of the third radiating elements is 5.8 millimeters.

8. The antenna unit of claim 7, wherein, The plurality of radiating elements are rectangular in shape, preferably, the plurality of radiating elements are square in shape with the same side length, and preferably, a number of the plurality of radiating elements is four.

9. The antenna unit of claim 8, wherein, The plurality of radiating elements and the plurality of coupling gaps are of a periodic structure.

10. The antenna unit of claim 1, wherein, ​ 11. The antenna unit according to any one of claims 1 to 10, wherein, ​ 12. The antenna unit according to any one of claims 1 to 11, wherein, The plurality of coupling slots comprises a first coupling slot pair and a second coupling slot pair, the coupling slots of the two coupling slot pairs are respectively arranged opposite to each other, the feeding units comprise a first feeding unit and a second feeding unit, the first feeding unit is respectively coupled to the first coupling slot pair, and the second feeding unit is respectively coupled to the second coupling slot pair; preferably, the power distribution ratio of the first feeding unit and the second feeding unit is 1:

1.

13. The antenna unit of claim 12, wherein, The first feeding unit comprises a first power distribution structure, the first power distribution structure comprises a first input section and two first output sections, the first input section is used to be connected with a first feeding network, and the two first output sections are used to be coupled to the first coupling slot pair; and The second feeding unit comprises a second power distribution structure, the second power distribution structure comprises a second input section and two second output sections, the second input section is used to be connected with a second feeding network, and the two second output sections are used to be coupled to the second coupling slot pair.

14. The antenna unit of claim 13, wherein, The first power distribution structure further comprises two first quarter-wave transformers, the two first quarter-wave transformers are respectively connected to the first input section close to one end of the first output section, the two first output sections are respectively connected to the first input section through the two first quarter-wave transformers, so that the first input section and the two first output sections are impedance matched; and / or The second power distribution structure further comprises a second quarter-wave transformer, the second quarter-wave transformer is connected to the second input section close to one end of the second output section, and the two second output sections are respectively connected to the second input section through the second quarter-wave transformer, so that the second input section and the two second output sections are impedance matched.

15. The antenna unit according to claim 13 or 14, wherein, The first output section is respectively connected with a fan-shaped stub at one end away from the first input section; and / or The second output section is respectively connected with a fan-shaped stub at one end away from the second input section. Preferably, the radius of the fan-shaped stub is 0.1-0.2 times the wavelength of the waveguide, and the unfolding angle of the fan-shaped stub is 90-120°.

16. An array antenna, comprising a feeding network and a plurality of antenna units as claimed in any one of claims 1 to 15, the plurality of antenna units are arranged in an array, and the feeding network is coupled to the feeding units of the antenna units.

17. The array antenna of claim 16, wherein, The feeding network comprises a first feeding network and a second feeding network, the first feeding network is coupled to the first feeding units of the antenna units, and the second feeding network is coupled to the second feeding units of the antenna units.

18. The array antenna of claim 16 or 17, wherein, The array antenna comprises eight antenna units, and the eight antenna units are arranged in a one-dimensional line; Preferably, in the arrangement direction of the eight antenna units, the distance between the centers of two adjacent antenna units is 0.5-1 times the wavelength of the array antenna.

19. The array antenna of any of claims 16 to 18, wherein, The array antenna further comprises a reflecting plate, the reflecting plate is located on the side of the first dielectric substrate away from the radiating unit, and the distance between the second dielectric substrate and the reflecting plate is a quarter wavelength. 20.A network device, comprising the antenna unit of any one of claims 1 to 15.

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