An antenna device and an antenna system

Abstract

The application discloses an antenna device and an antenna system. The antenna device is an antenna array composed of multiple microstrip antenna units. Each microstrip antenna unit comprises a dielectric substrate, a radiation patch, a metal back plate, a feed probe and a shorting post. The radiation patch is located on the upper surface of the dielectric substrate, the metal back plate is located on the lower surface of the dielectric substrate, the feed probe penetrates the dielectric substrate to connect one end of the radiation patch with the metal back plate, and the shorting post penetrates the dielectric substrate to connect the other end of the radiation patch with the metal back plate. By configuring the shorting post on the radiation patch and simultaneously exciting the first-order mode and the second-order mode, the radiation power of the microstrip antenna unit in a preset area can be suppressed to generate a radiation zero point, so that the signal radiated by the microstrip antenna unit has asymmetry, and the asymmetry of the antenna array is realized. The antenna system composed of the antenna array can realize the coupling suppression of the transmitting and receiving arrays of the antenna system, and further improve the isolation of the transmitting and receiving arrays.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of communications, and in particular to an antenna device and an antenna system. BACKGROUND

[0002] With the continuous rise of mobile communication capacity demand, not only the communication frequency of the base station gradually develops to the high frequency band providing large broadband, but also higher requirements are put forward for full duplex communication of high frequency macro station. For example, if the base station simultaneously undertakes the transmission tasks of enhanced mobile broadband (eMBB) and uplink centric broadband communication (UCBC), it is required that eMBB and UCBC have a certain isolation degree when working simultaneously at the same frequency, and mutual interference generated between the arrays in the station is minimized. Therefore, how to improve the isolation degree of the receiving and transmitting arrays to ensure the normal work of the full duplex system of the high frequency macro station is the key research direction of the current base station communication.

[0003] To this end, the conventional technology proposes to load an isolation wall in the receiving and transmitting antenna array, and to realize decoupling between the receiving and transmitting arrays by loading a choke groove in the isolation wall, thereby improving the isolation degree of the receiving and transmitting arrays.

[0004] However, the size of the decoupling structure (such as the isolation wall, the choke groove, etc.) loaded in the conventional technology is large, and it is difficult to be applied to compact arrays, multiple-input multiple-output (MIMO) and other application scenarios.

[0005] Therefore, there is an urgent need for an antenna device that can solve the decoupling between the receiving and transmitting arrays and thereby improve the isolation degree of the receiving and transmitting arrays. SUMMARY

[0006] The present application provides an antenna device and an antenna system for realizing receiving and transmitting array coupling suppression of the antenna system by suppressing the radiation power at a specific angle, thereby improving the isolation degree of the receiving and transmitting arrays.

[0007] In a first aspect, the present application provides an antenna device, which is an antenna array composed of a plurality of microstrip antenna units. Each microstrip antenna unit comprises at least one polarization unit, and each polarization unit comprises a dielectric substrate, a radiation patch, a metal backplane, a feed probe and a shorting post. The radiation patch is located on the upper surface of the dielectric substrate, the metal backplane is located on the lower surface of the dielectric substrate, the feed probe connects one end of the radiation patch and the metal backplane through the dielectric substrate, and the shorting post connects the other end of the radiation patch and the metal backplane through the dielectric substrate. When the antenna device is in operation, each microstrip antenna unit is used to generate an asymmetric radiation signal at a working frequency point by simultaneously exciting a first-order mode and a second-order mode through the radiation patch, and the asymmetric radiation signal has a radiation null point in a preset area, and the working frequency point is between the frequency point corresponding to the first-order mode and the frequency point corresponding to the second-order mode.

[0008] In the present application, by configuring the shorting post on the radiation patch and simultaneously exciting the first-order mode and the second-order mode, the radiation power of the microstrip antenna unit in the preset area can be suppressed to generate a radiation null point, so that the signal radiated by the microstrip antenna unit has asymmetry, and the antenna signal radiated by the antenna array composed of the plurality of microstrip antenna units also has asymmetry. Therefore, the antenna system composed of the antenna array can realize the coupling suppression of the transmit-receive array of the antenna system, and further improve the isolation of the transmit-receive array.

[0009] In a possible implementation, the shorting post is located near the electric wall generated by the second-order mode on the radiation patch, and the position of the shorting post does not overlap with the position of the electric wall generated by the first-order mode on the radiation patch.

[0010] In the present embodiment, the shorting post is configured near the electric wall of the second-order mode, which can move the resonant frequency of the first-order mode to a high frequency without affecting the resonant frequency of the second-order mode. Therefore, it is beneficial to narrow the frequency corresponding to the first-order mode and the frequency corresponding to the second-order mode, and further improve the matching effect of the antenna.

[0011] In a possible implementation, the distance between the shorting post and the feed probe is greater than 3 / 4 times the length of the radiation patch, and the length of the radiation patch is related to the wavelength corresponding to the working frequency point.

[0012] In the present embodiment, since the electric wall of the second-order mode is generally at 3 / 4 of the length of the radiation patch, the distance between the shorting post and the feed probe is greater than 3 / 4 times the length of the radiation patch after adjusting the amplitude and phase by adjusting the shorting post. It is beneficial to adjust the radiation null point to the preset area while ensuring that the microstrip antenna unit can radiate an asymmetric signal, and further beneficial to realize the coupling suppression of the transmit-receive array of the antenna system, and further improve the isolation of the transmit-receive array.

[0013] In a possible implementation, the radiation patch is a slow wave transmission structure with stub loading along the length direction, and the length of the radiation patch is less than or equal to 1 / 2 of the wavelength corresponding to the operating frequency point.

[0014] For example, the length of the radiation patch is approximately equal to 0.4 times the wavelength corresponding to the operating frequency point.

[0015] In the embodiment, when the operating frequency point of the microstrip antenna unit is between the first-order mode and the second-order mode, the size of the microstrip antenna unit is large, which may not be suitable for compact array applications. Therefore, the radiation patch is made into a slow wave transmission structure with stub loading, which is beneficial to shorten the size of the radiation patch and greatly reduce the waveguide wavelength, thereby realizing the miniaturization of the microstrip antenna unit.

[0016] In a possible implementation, the at least one polarization unit is a ±45° dual-polarized unit, wherein the radiation patch of the +45° polarization unit is placed in cross with the radiation patch of the -45° polarization unit, and an insulating medium is arranged between the radiation patch of the +45° polarization unit and the radiation patch of the -45° polarization unit.

[0017] In the embodiment, each microstrip antenna unit is configured as a dual-polarized unit. Compared with using a single-polarized unit to realize a microstrip antenna unit, using a dual-polarized unit not only increases the degree of freedom of the antenna, but also increases the communication capacity and improves the anti-interference ability, thereby being beneficial to improving the communication performance of the antenna device.

[0018] In a possible implementation, the distance between the short-circuit post of the +45° polarization unit and the end of the radiation patch of the +45° polarization unit is not equal to the distance between the short-circuit post of the -45° polarization unit and the end of the radiation patch of the -45° polarization unit.

[0019] In the embodiment, the distances from the short-circuit post to the ends of the radiation patches of the two polarization units are different, which is beneficial to increasing the asymmetry of the radiation signals radiated by the microstrip antenna unit.

[0020] In a possible implementation, the microstrip antenna unit further includes a plurality of scattering posts, and the plurality of scattering posts are symmetrically distributed around the at least one polarization unit.

[0021] For example, the plurality of scattering posts are located on one side of the line connecting the positions of the two feed probes of the ±45° dual-polarized unit, the plurality of scattering posts are symmetrically distributed based on the perpendicular bisector of the line connecting the positions of the two feed probes, and the center-to-center distance of adjacent two scattering posts in the plurality of scattering posts is consistent.

[0022] In the embodiment, when the scattering column is loaded, the surface current near the metal base plate where the microstrip antenna unit is located is more concentrated in the area near the loaded scattering column. Therefore, by arranging the scattering column around at least one polarization unit of the microstrip antenna unit, the suppression effect of the radiation power of the preset area is enhanced, and the asymmetry of the signal radiated by the microstrip antenna unit is enhanced.

[0023] In a possible implementation, the antenna device further includes a plurality of electromagnetic bandgap structures, which are uniformly distributed around the subarray including the at least two microstrip antenna units.

[0024] In the embodiment, the electromagnetic bandgap structure has frequency bandgap and phase bandgap characteristics, and can affect the propagation of electromagnetic waves within a certain frequency band. After the plurality of microstrip antenna units are arrayed, coupling may occur between the microstrip antenna units, resulting in a decrease in the asymmetry performance (suppression performance). The embodiment increases the electromagnetic bandgap structure to suppress the aforementioned coupling and enhance the isolation between the microstrip antenna units, thereby strengthening the asymmetry performance (suppression performance), that is, the asymmetry performance of the antenna array is consistent with the asymmetry performance of the microstrip antenna unit.

[0025] In a possible implementation, the electromagnetic bandgap structure includes a metal column and a conductor sheet, the conductor sheet is located on the surface of the dielectric substrate, and the metal column penetrates the dielectric substrate and is connected to the geometric center of the conductor sheet.

[0026] In a possible implementation, the subarray includes two microstrip antenna units. For example, the subarray is a 1x2 subarray or a 2x1 subarray.

[0027] In a second aspect, the present application provides an antenna system, which includes a transmitting array and a receiving array. The transmitting array is used to transmit an asymmetric radiation signal, and the receiving array is used to receive an asymmetric radiation signal. The transmitting array can be implemented by using the antenna device described in any one of the embodiments of the first aspect, and the receiving array can be implemented by using the antenna device described in any one of the embodiments of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 An embodiment of the microstrip antenna unit provided by the present application is shown in the figure;

[0029] Figure 2A An example of the design principle of the microstrip antenna unit provided by the present application is shown in the figure;

[0030] Figure 2B For Figure 2A An example of the comparison of the directional diagrams of the microstrip antenna units corresponding to each step is shown in the figure;

[0031] Figure 3A A top view of a miniaturized microstrip antenna element provided for the present application;

[0032] Figure 3B A perspective view of a miniaturized microstrip antenna element provided for the present application;

[0033] Figure 4A A perspective view of a miniaturized dual-polarized microstrip antenna element provided for the present application;

[0034] Figure 4B A top view and a cross-sectional view of a miniaturized dual-polarized microstrip antenna element provided for the present application;

[0035] Figure 5A A perspective view of a microstrip antenna element provided for the present application with a scattering post;

[0036] Figure 5B A top view of a microstrip antenna element provided for the present application with a scattering post;

[0037] Figure 6 Surface current distribution on the metal ground plane for the dual-polarized antenna element of the present application without and with a scattering post, respectively;

[0038] Figure 7 An example plot of the comparison of the radiation pattern of the dual-polarized antenna element of the present application with that of a conventional dual-polarized antenna element;

[0039] Figure 8A A perspective view of an electromagnetic bandgap structure provided for the present application;

[0040] Figure 8B A top view of an electromagnetic bandgap structure provided for the present application;

[0041] Figure 9 An example plot of the dispersion curve obtained from the simulation of the electromagnetic bandgap structure provided for the present application under periodic boundary conditions;

[0042] Figure 10 An example plot of an antenna array composed of a plurality of microstrip antenna elements and a plurality of electromagnetic bandgap structures provided for the present application;

[0043] Figure 11 An example plot of the impedance bandwidth of the antenna array provided for the present application;

[0044] Figure 12 An example plot of the comparison of the radiation pattern of the antenna array provided for the present application with that of a conventional antenna array at 25.5 GHz;

[0045] Figure 13An example diagram of port isolation of an antenna array provided in the present application compared with a conventional antenna array;

[0046] Figure 14 An example diagram of an antenna system composed of an antenna array provided in the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be apparently and completely described in combination with 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.

[0048] The terms "first", "second", "third", "fourth" and the like (if any) in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the terms thus used can be interchanged under appropriate circumstances, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0049] It should be understood that the term "and / or" herein is only used to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0050] The professional terms related to the present application will be introduced simply as follows:

[0051] Asymmetry: refers to the radiation pattern of the antenna being asymmetric. Compared with the symmetric radiation pattern possessed by the conventional antenna, since the antenna unit proposed in the present application can effectively suppress the radiation power in the lateral specific region, but does not suppress the radiation power in the opposite lateral region, the radiation patterns on both sides do not present the same characteristics, and thus are called asymmetric.

[0052] First-order mode: refers to the electric field distribution along the length direction (i.e. the direction of the longer side) of the radiation patch of the microstrip antenna unit having only one half-wave field intensity mode. For example, as shown in FIG. 1, the electric field distribution along the length direction of the radiation patch of the microstrip antenna unit has only one half-wave field intensity mode, and thus is called the first-order mode. Figure 1As shown in FIG. 1, if the direction of the longer side of the radiation patch is defined as the y direction, and the direction of the shorter side of the radiation patch is defined as the x direction, the first-order mode is a TM01 mode. For another example, if the direction of the longer side of the radiation patch is defined as the x direction, and the direction of the shorter side of the radiation patch is defined as the y direction, the first-order mode is a TM10 mode. The present application is described in the example shown in FIG. 1. Figure 1 As shown in FIG. 1, if the direction of the longer side of the radiation patch is defined as the y direction, and the direction of the shorter side of the radiation patch is defined as the x direction, the first-order mode is a TM01 mode. For another example, if the direction of the longer side of the radiation patch is defined as the x direction, and the direction of the shorter side of the radiation patch is defined as the y direction, the first-order mode is a TM10 mode. The present application is described in the example shown in FIG. 1.

[0053] Second-order mode: refers to the electric field distribution having 2 half-wave field intensity modes along the length direction (i.e., the direction of the longer side) of the radiation patch of the microstrip antenna unit. For example, as shown in FIG. 2, if the direction of the longer side of the radiation patch is defined as the y direction, and the direction of the shorter side of the radiation patch is defined as the x direction, the second-order mode is a TM02 mode. For another example, if the direction of the longer side of the radiation patch is defined as the x direction, and the direction of the shorter side of the radiation patch is defined as the y direction, the second-order mode is a TM20 mode. The present application is described in the example shown in FIG. 2. Figure 1 As shown in FIG. 2, if the direction of the longer side of the radiation patch is defined as the y direction, and the direction of the shorter side of the radiation patch is defined as the x direction, the second-order mode is a TM02 mode. For another example, if the direction of the longer side of the radiation patch is defined as the x direction, and the direction of the shorter side of the radiation patch is defined as the y direction, the second-order mode is a TM20 mode. The present application is described in the example shown in FIG. 2. Figure 1 As shown in FIG. 2, if the direction of the longer side of the radiation patch is defined as the y direction, and the direction of the shorter side of the radiation patch is defined as the x direction, the second-order mode is a TM02 mode. For another example, if the direction of the longer side of the radiation patch is defined as the x direction, and the direction of the shorter side of the radiation patch is defined as the y direction, the second-order mode is a TM20 mode. The present application is described in the example shown in FIG. 2.

[0054] Electric wall: refers to a curved surface satisfying the ideal conductor boundary condition, i.e., E and H are both 0 inside the conductor. Electric lines are perpendicular to the surface of the conductor; magnetic lines are parallel to the surface of the conductor. Generally, the surface intersecting the electric lines perpendicularly is referred to as an electric wall.

[0055] Spatial angle filtering antenna: refers to an antenna unit capable of effectively suppressing the radiation power in a specific angle region in the lateral direction compared with the symmetrical radiation pattern possessed by a conventional antenna, thereby causing a radiation zero point in the direction. The antenna unit is a spatial angle filtering antenna.

[0056] The antenna device provided by the present application comprises an antenna array composed of a plurality of microstrip antenna units. Since the directional pattern of the signal radiated by each microstrip antenna unit is asymmetric, the signal radiated by the antenna device as a whole also has good asymmetry, which is beneficial to realize the transmit-receive array coupling suppression of the antenna system, and further improve the isolation of the transmit-receive array.

[0057] The structure of each microstrip antenna unit 10 is described as follows: Figure 1 The structure of each microstrip antenna unit 10 is described as follows:

[0058] As shown in FIG. 1, if the direction of the longer side of the radiation patch is defined as the y direction, and the direction of the shorter side of the radiation patch is defined as the x direction, the first-order mode is a TM01 mode. For another example, if the direction of the longer side of the radiation patch is defined as the x direction, and the direction of the shorter side of the radiation patch is defined as the y direction, the first-order mode is a TM10 mode. The present application is described in the example shown in FIG. 1. Figure 1As shown, it is a schematic diagram of an embodiment of the microstrip antenna unit 10 provided by the present application. Each microstrip antenna unit 10 comprises a dielectric substrate 101, a radiating patch 102, a metal ground plate 103, a feeding probe 104 and a shorting post 105. It is to be noted that when a plurality of microstrip antenna units 10 constitute an antenna array, the plurality of microstrip antenna units 10 share the same dielectric substrate 101, and the plurality of microstrip antenna units 10 share the same metal ground plate 103.

[0059] Wherein, the dielectric substrate 101 is composed of insulating dielectric, the radiating patch 102, the metal ground plate 103, the feeding probe 104 and the shorting post 105 are respectively made of conductive material such as metal. The dielectric substrate 101 is used to carry the radiating patch 102 and the metal ground plate 103. The radiating patch 102 as a radiator is located on the upper surface of the dielectric substrate 101, and the metal ground plate 103 as a ground plate is located on the lower surface of the dielectric substrate 101. The feeding probe 104 as a feeding device connects the radiating patch 102 and the metal ground plate 103. The shorting post 105 as a shorting device realizes the short connection between the radiating patch 102 and the metal ground plate 103. The feeding probe 104 and the shorting post 105 are respectively located at both ends of the radiating patch 102. For example, the feeding probe 104 penetrates the dielectric substrate 101 to connect one end of the radiating patch 102 with the metal ground plate 103, and the shorting post 105 penetrates the dielectric substrate 101 to connect the other end of the radiating patch 102 with the metal ground plate 103.

[0060] When the microstrip antenna unit 10 works, the microstrip antenna unit 10 generates an asymmetric radiation signal at the operating frequency point by simultaneously exciting the first-order mode and the second-order mode through the radiating patch 102, and the asymmetric radiation signal has a radiation zero point in the preset area, and the operating frequency point is between the frequency point corresponding to the first-order mode and the frequency point corresponding to the second-order mode.

[0061] Wherein, the first-order mode is a field intensity mode with only one half wave of electric field distribution along the length direction of the radiating patch 102 of the microstrip antenna unit 10 (i.e. the direction of the longer side); the second-order mode is a field intensity mode with two half waves of electric field distribution along the length direction of the radiating patch 102 of the microstrip antenna unit 10 (i.e. the direction of the longer side). When the microstrip antenna unit 10 excites the first-order mode and the second-order mode through the radiating patch 102 configured with the shorting post 105, the radiating patch 102 generates unevenly distributed current and radiates an asymmetric radiation signal. Wherein, the asymmetric radiation signal has a radiation zero point in the preset area, that is, the radiation power of the antenna pattern in the preset area is low, and the radiation power of the whole pattern presents an asymmetric distribution rule. Optionally, the shorting post 105 is located near the electric wall generated by the second-order mode on the radiating patch, and the position of the shorting post 105 does not overlap with the electric wall generated by the first-order mode on the radiating patch.

[0062] To facilitate understanding, the following will be combined with Figure 2A The principle behind the asymmetric signal radiated by this microstrip antenna element is explained:

[0063] Figure 2A Step 1 in the diagram is an example of a microstrip antenna element without a short-circuit device and using a feed probe. When the microstrip antenna element simultaneously excites a first-order mode (e.g., TM01 mode) and a second-order mode (e.g., TM02 mode), although it can cause uneven current distribution on the patch, the frequency points corresponding to the first-order mode and the second-order mode differ by a factor of two. That is, the frequency point f2 corresponding to the second-order mode is equal to twice the frequency point corresponding to the first-order mode, making it difficult for the two modes to match in the same frequency band. In order to successfully excite the two modes simultaneously, a short-circuit post is added to the edge of the microstrip antenna element to bring the two modes closer, thereby improving the antenna matching effect. Figure 2A As shown in step 2, a short-circuit post is placed near the electric wall of the second-order mode to bring the corresponding frequency points of the two modes closer together. For example, after placing the short-circuit post on the radiating patch, the center frequency of the first-order mode can be shifted towards the second-order mode while keeping the frequency of the second-order mode unchanged, thereby reducing the frequency difference between the first-order and second-order modes. For example, in Figure 2A In step 2, the difference between f2 and f1 is less than Figure 2A The difference between f2 and f1. Then, as... Figure 2A As shown in step 3, moving the short-circuit post away from the feed probe can bring the corresponding frequency points of the two modes closer together while adjusting the current amplitude ratio and phase difference of the two modes, so that the signal radiated by the microstrip antenna element can suppress radiated energy and produce a radiation null point in the preset region. Figure 2B In the example shown, by adjusting the position of the shorting post, the microstrip antenna element exhibits a radiation null point near 60°. In this example, placing the shorting post near the electric wall of the second-order mode allows the resonant frequency of the first-order mode to be shifted to a higher frequency without affecting the resonant frequency of the second-order mode. Therefore, it is beneficial to bring the frequencies corresponding to the first-order mode and the second-order mode closer together, thereby improving the antenna's matching performance.

[0064] In this embodiment, by configuring short-circuit posts 105 on the radiating patch 102 and simultaneously exciting the first-order and second-order modes, the radiated power of the microstrip antenna element 10 in a preset area can be suppressed to generate a radiation null. Therefore, the signal radiated by the microstrip antenna element 10 can be made asymmetrical, and consequently, the antenna signal radiated by the antenna array composed of the aforementioned multiple microstrip antenna elements 10 is also asymmetrical. Therefore, the antenna system composed of this antenna array can achieve suppression of the transmitting and receiving array coupling of the antenna system, thereby improving the isolation of the transmitting and receiving arrays.

[0065] Optionally, the distance between the shorting post 105 and the feed probe 104 (i.e.Figure 1 L0 in the diagram is greater than the length of the radiation patch 102 (i.e., Figure 1 The length of the radiating patch 102 is related to the wavelength corresponding to the operating frequency, which is 3 / 4 times the length of L1 in the image. For example, the length of the radiating patch 102 is 0.5 times the wavelength corresponding to the operating frequency. Since the electric barrier of the second-order mode is generally located at 3 / 4 of the length of the radiating patch 102, after adjusting the amplitude and phase by adjusting the shorting post 105, the distance between the shorting post 105 and the feed probe 104 is greater than 3 / 4 times the length of the radiating patch 102. This is beneficial for adjusting the radiation null point to a preset region while ensuring that the microstrip antenna element can radiate non-corresponding signals, thereby facilitating the suppression of transmit and receive array coupling in the antenna system and improving the isolation of the transmit and receive arrays.

[0066] Furthermore, in one possible implementation, such as Figure 3A and Figure 3B As shown, the radiating patch 102 exhibits a stubbed slow-wave transmission structure along its length. This stubbed slow-wave transmission structure has a symmetrical sawtooth shape along the length of the radiating patch 102. Configuring the radiating patch 102 as a stubbed slow-wave transmission structure reduces the length of the radiating patch 102; that is, to obtain the same radiated signal, the length of the radiating patch configured with the stubbed slow-wave transmission structure (e.g., ...) is significantly reduced. Figure 3A L1' in the image is longer than the length of a typical rectangular radiating patch (e.g., Figure 1 The length of the radiating patch 102 is less than or equal to half the wavelength corresponding to the operating frequency. For example, the length of the radiating patch 102 is approximately 0.4 times the wavelength corresponding to the operating frequency. For example, the width of the radiating patch 102 is approximately 0.08 times the wavelength corresponding to the operating frequency.

[0067] In this embodiment, when the operating frequency of the microstrip antenna element 10 is between the first-order mode and the second-order mode, the size of the microstrip antenna element is relatively large (i.e., the size of the radiating patch along the length direction is relatively large, for example, the size of the radiating patch along the length direction is greater than or close to 1 / 2 times the wavelength corresponding to the operating frequency), which may be unsuitable for compact array applications. Therefore, making the radiating patch into a stub-loaded slow-wave transmission structure is beneficial to shortening the size of the radiating patch, significantly reducing the waveguide wavelength, thereby realizing the miniaturization of the microstrip antenna element size.

[0068] Furthermore, each microstrip antenna element 10 includes at least one polarization element.

[0069] In one possible implementation, such as Figure 4AIn the example (a) on the left side, each microstrip antenna unit 10 includes one polarization unit, and each polarization unit includes one radiating patch 102, one feeding probe 104 and one shorting post 105. When multiple single-polarized microstrip antenna units 10 form an antenna array, the multiple microstrip antenna units 10 share the same dielectric substrate 101, and the multiple microstrip antenna units 10 share the same metal ground plane 103.

[0070] In another possible implementation, as shown in Figure 4A In the example (b) on the left side, each microstrip antenna unit 10 includes two polarization units with different polarization directions, i.e. each microstrip antenna unit 10 is a dual-polarized unit. Since each polarization unit includes one radiating patch 102, one feeding probe 104 and one shorting post 105, each microstrip antenna unit 10 includes two radiating patches 102, two feeding probes 104 and two shorting posts 105, and the two polarization units share the same dielectric substrate 101 and the same metal ground plane 103.

[0071] In the example (b) as shown in Figure 4A The microstrip antenna unit 10 is a ±45° dual-polarized unit. The radiating patch of the +45° polarization unit is cross-placed with the radiating patch of the -45° polarization unit, and an insulating medium is arranged between the radiating patch of the +45° polarization unit and the radiating patch of the -45° polarization unit.

[0072] As shown in the example (b) as shown in Figure 4B The microstrip antenna unit includes two layers of dielectric substrates (i.e. the dielectric substrate 101-1 and the dielectric substrate 101-2). The upper layer of dielectric substrate 101-1 is mainly used for printing the radiating patch 102-1 of the -45° polarization unit, and the lower layer of dielectric substrate 101-2 is mainly used for printing the radiating patch 102-2 of the +45° polarization unit and the metal ground plane 103. For example, the radiating patch 102-1 of the -45° polarization unit is located on the upper surface of the upper layer of dielectric substrate 101-1, the radiating patch 102-2 of the +45° polarization unit is located on the upper surface of the lower layer of dielectric substrate 101-2, and the metal ground plane 103 is located on the lower surface of the lower layer of dielectric substrate 101-2.

[0073] Optionally, the distance between the shorting post 105 of the +45° polarization unit and the end of the radiating patch 102-2 of the +45° polarization unit is not equal to the distance between the shorting post 105 of the -45° polarization unit and the end of the radiating patch 102-1 of the -45° polarization unit.

[0074] In this embodiment, each microstrip antenna unit 10 is configured as a dual-polarized unit. Compared with using a single-polarized unit to implement the microstrip antenna unit 10, using a dual-polarized unit not only increases the degree of freedom of the antenna, but also increases the communication capacity and improves the anti-interference ability, thereby facilitating the improvement of the communication performance of the antenna system. In addition, the distance from the shorting post 105 to the end of the radiation patch of the two polarized units is different, which is conducive to increasing the asymmetry of the radiation signals radiated by the microstrip antenna unit 10.

[0075] Further, in a possible implementation, the microstrip antenna unit 10 further includes a plurality of scattering columns, and the plurality of scattering columns are symmetrically distributed around the at least one polarized unit.

[0076] As shown in Figure 5A and Figure 5B , a ±45° dual-polarized unit is taken as an example for introduction. The plurality of scattering columns 106 are symmetrically distributed around the ±45° dual-polarized unit. Optionally, the plurality of scattering columns 106 are located on one side of the line connecting the positions of the two feed probes 104 of the ±45° dual-polarized unit, and the plurality of scattering columns 106 are symmetrically distributed based on the perpendicular bisector of the line connecting the positions of the two feed probes 104.

[0077] Optionally, the center-to-center distance of adjacent two scattering columns 106 in the plurality of scattering columns 106 is consistent, that is, the plurality of scattering columns 106 are uniformly distributed around the ±45° dual-polarized unit. In the example shown in Figure 5B , 24 scattering columns 106 are configured around the ±45° dual-polarized unit. It should be understood that in actual application, the number of scattering columns 106 configured around the ±45° dual-polarized unit can be adjusted, and accordingly, the center-to-center distance of adjacent two scattering columns 106 can also be adjusted, which is not limited herein.

[0078] In an example, as shown in Figure 5A and Figure 5B , the radius R1 of the scattering column 106 is 0.1mm-0.2mm, and the center-to-center distance d4 of adjacent scattering columns 106 is 0.4mm-0.8mm. The radius R2 of the shorting post 105 is 0.05mm-0.2mm. The length L3 of the radiation patch 102-1 of the-45° polarized unit is 3.3mm-3.9mm, and the width W3 is 0.84mm-1.24mm; the length L4 of the radiation patch 102-2 of the +45° polarized unit is 3mm-3.6mm, and the width W4 is 0.84mm-1.24mm.

[0079] As shown in Figure 6 , the surface current distribution diagrams of the dual-polarized antenna unit of the present application on the metal back plate in the cases of not loading the scattering column and loading the scattering column are shown. As shown in Figure 6As shown, when the scattering column 106 is loaded, the surface current near the metal base plate 103 where the microstrip antenna unit 10 is located will be more concentrated in the area near the loaded scattering column 106. Therefore, by arranging the scattering column 106 around at least one polarization unit of the microstrip antenna unit 10, it is beneficial to enhance the suppression effect of the radiation power of the preset area and enhance the asymmetry of the signal radiated by the microstrip antenna unit 10.

[0080] In addition, as Figure 7 shown, the 25GHz antenna unit pattern comparison of the dual-polarized antenna unit with spatial angle filtering capability and the conventional dual-polarized antenna unit of the present application. Compared with the conventional antenna unit, the sidelobe level of the dual-polarized antenna unit proposed in the present application is reduced by 3.8dB, that is, it can effectively suppress the sidelobe level at a specific angle and achieve good asymmetry.

[0081] Further, in a possible implementation, the antenna device provided by the present application further comprises a plurality of electromagnetic band gap structures (electromagnetic band gap, EBG) 20. Wherein, the electromagnetic band gap structure 20 is a kind of artificial periodic structure, it has frequency band gap and phase band gap characteristics, it can affect the propagation of electromagnetic wave in certain frequency band.

[0082] As Figure 8A shown, the electromagnetic band gap structure 20 includes metal column 201 and conductor sheet 202, the conductor sheet 202 is located on the surface of the dielectric substrate 101, and the metal column 201 penetrates the dielectric substrate 101 and is connected with the geometric center of the conductor sheet 202. As Figure 8A shown, the conductor sheet 202 in the electromagnetic band gap structure 20 can be a square metal patch, and the metal column 201 coincides with the geometric center of the square patch. Since the coupling between the microstrip antenna units 10 after arraying may cause the asymmetry performance (suppression performance) to decline, the electromagnetic band gap structure 20 is added to suppress the aforementioned coupling and enhance the isolation between the microstrip antenna units 10, thereby strengthening the asymmetry performance (suppression performance), that is, it is beneficial to make the asymmetry performance of the antenna array consistent with the asymmetry performance of the microstrip antenna unit.

[0083] In an example, as Figure 8B shown, the radius R of the metal column 201 is 0.05mm~0.15mm, the length L2 of the square patch is 0.3mm~0.7mm, and the width W2 is 0.3mm~0.7mm. Wherein, the length L2 of the square patch is related to the working frequency of the antenna unit. Taking the working frequency of the antenna unit as 25.8G for example, the length L2 of the square patch is about 0.04 times the wavelength of the working frequency.

[0084] As Figure 9The dispersion curve of the EBG structure 20 provided by the present application is shown in the simulation under the periodic boundary condition. It can be seen from the simulation result shown in Figure 9 that the surface wave at 19.5 GHz or even higher frequencies can be effectively suppressed under a specific size (for example, the size shown in the figure), and thus the radiation power in the preset area can be suppressed to obtain a radiation zero point. Figure 8B

[0085] Further, the plurality of EBG structures 20 are uniformly distributed around the subarray including at least two microstrip antenna units 10. Optionally, one subarray includes 2 microstrip antenna units 10. For example, the subarray including at least two microstrip antenna units 10 is a 1x2 subarray or a 2x1 subarray. Optionally, one subarray includes 4 microstrip antenna units 10. For example, the subarray including at least two microstrip antenna units 10 is a 2x2 subarray. Here, no limitation is made. Compared with the scheme in the prior art in which the plurality of EBG structures are only distributed around one microstrip antenna unit, the present application uniformly distributes the plurality of EBG structures around at least two microstrip antenna units, which is beneficial to keeping the consistency of the radiation direction of the at least two microstrip antenna units, and thus ensures the asymmetry of the directivity pattern of the entire antenna device.

[0086] For example, the subarray including at least two microstrip antenna units 10 is a 1x2 subarray. As shown in Figure 10 , every two microstrip antenna units 10 form a subarray (i.e., a 1x2 subarray), and the plurality of EBG structures 20 are uniformly distributed around the 1x2 subarray. In addition, the plurality of subarrays are regularly arranged into an antenna array, and the plurality of EBG structures 20 are uniformly distributed around each 1x2 subarray in the antenna array. For example, the row spacing between adjacent microstrip antenna units 10 in the antenna array is 0.6 times the wavelength corresponding to the operating frequency, and the column spacing between adjacent microstrip antenna units 10 is 0.5 times the wavelength corresponding to the operating frequency.

[0087] In one example, as shown in Figure 10 , the antenna array includes 64 dual-polarized antenna units, the antenna array has a size of 8x8, the row spacing d1 between adjacent microstrip antenna units 10 is 7mm~8mm, the column spacing d2 between adjacent microstrip antenna units 10 is 5.75mm~6.75mm, and the spacing d3 between adjacent EBG structures 20 is 0.87mm~1.27mm.

[0088] As shown in Figure 11 , the impedance bandwidth of the antenna array with the spatial angle filtering capability provided by the present application is shown. It can be seen from the simulation result shown in Figure 11 that the impedance bandwidth of the antenna array ranges from 24.7GHz to 27.1GHz.

[0089] As shown in Figure 12 ​As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz. Figure 12 As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz.

[0090] As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz. Figure 13 As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz. Figure 13 As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz.

[0091] As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz. Figure 14 As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz. Figure 10 As shown in the simulation results, compared with the conventional antenna array, the antenna array provided by the present application can reduce the sidelobe level by 3.89 dB at 25 GHz.

[0092] In the embodiment, not only the microstrip antenna unit 10 is used to suppress the radiation power in the preset area to generate the radiation null, but also the electromagnetic bandgap structure 20 is used to construct a 1x2 subarray form to make the radiation patterns of the microstrip antenna units 10 in the array have good consistency. Therefore, the antenna array composed of the microstrip antenna unit 10 and the electromagnetic bandgap structure 20 can not only realize the coupling suppression of the transmit-receive array of the antenna system and further improve the isolation of the transmit-receive surface, but also ensure that the transmit-receive antenna array has good isolation under the quasi-far-field distance and in the case of independent scanning.

[0093] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the same. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features. The modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments.

Claims

1. An antenna device, characterized by The antenna device comprises: an antenna array comprising a plurality of microstrip antenna units, each of the microstrip antenna units comprising at least one polarization unit, each of the polarization units comprising a dielectric substrate, a radiating patch, a metal ground plate, a feeding probe and a shorting post, the radiating patch being located on an upper surface of the dielectric substrate, the metal ground plate being located on a lower surface of the dielectric substrate, the feeding probe connecting one end of the radiating patch and the metal ground plate through the dielectric substrate, and the shorting post connecting the other end of the radiating patch and the metal ground plate through the dielectric substrate; each of the microstrip antenna units is configured to generate an asymmetric radiation signal at a working frequency point by simultaneously exciting a first-order mode and a second-order mode through the radiating patch, the asymmetric radiation signal having a radiation null point in a preset area, and the working frequency point being located between a frequency point corresponding to the first-order mode and a frequency point corresponding to the second-order mode.

2. The antenna device of claim 1, wherein, The shorting post is located in the vicinity of an electric wall generated by the second-order mode on the radiating patch, and a position of the shorting post does not overlap with a position of an electric wall generated by the first-order mode on the radiating patch.

3. The antenna device according to claim 1 or 2, characterized in that A distance between the shorting post and the feeding probe is greater than 3 / 4 times a length of the radiating patch, and the length of the radiating patch is related to a wavelength corresponding to the working frequency point.

4. The antenna device according to claim 1 or 2, characterized in that The radiating patch presents a slow-wave transmission structure of stub loading in a length direction, and the length of the radiating patch is less than or equal to 1 / 2 times the wavelength corresponding to the working frequency point.

5. The antenna device according to claim 1 or 2, characterized in that The at least one polarization unit is a ±45° dual-polarized unit, wherein the radiating patch of a +45° polarization unit and the radiating patch of a -45° polarization unit are cross-placed, and an insulating medium is arranged between the radiating patch of the +45° polarization unit and the radiating patch of the -45° polarization unit.

6. The antenna device of claim 5, wherein, A distance between the shorting post of the +45° polarization unit and an end of the radiating patch of the +45° polarization unit is not equal to a distance between the shorting post of the -45° polarization unit and an end of the radiating patch of the -45° polarization unit.

7. The antenna device according to claim 1 or 2, characterized in that The microstrip antenna unit further comprises a plurality of scattering posts, and the plurality of scattering posts are symmetrically distributed around the at least one polarization unit.

8. The antenna device of claim 7, wherein, The plurality of scattering posts are located on one side of a line connecting positions of two feeding probes of the ±45° dual-polarized unit, the plurality of scattering posts are symmetrically distributed based on a perpendicular bisector of the line connecting the positions of the two feeding probes, and a center distance between adjacent two scattering posts in the plurality of scattering posts is consistent.

9. The antenna device according to claim 1 or 2, characterized in that The antenna device further comprises a plurality of electromagnetic bandgap structures, and the plurality of electromagnetic bandgap structures are uniformly distributed around a subarray comprising at least two microstrip antenna units.

10. The antenna device of claim 9, wherein, The electromagnetic bandgap structure comprises a metal post and a conductor sheet, the conductor sheet is located on a surface of the dielectric substrate, and the metal post connects a geometric center of the conductor sheet through the dielectric substrate.

11. The antenna device of claim 9, wherein, The subarray comprises two microstrip antenna units, and the subarray is a 1×2 subarray or a 2×1 subarray.

12. An antenna system, characterized by The antenna device comprises: a transmitting array as claimed in any of the claims 1 to 11, and a receiving array as claimed in any of the claims 1 to 11; the transmitting array for transmitting an asymmetric radiation signal; the receiving array for receiving the asymmetric radiation signal.

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