A ku-band structure-complementary miniaturized high-isolation microstrip MIMO antenna

Abstract

The application designs a Ku-band structure complementary small-size high-isolation microstrip MIMO antenna, which comprises a first unit antenna structure, a second unit antenna structure, a dielectric substrate, a metal ground plate and an isolation rectangular patch; the metal ground plate is arranged on the lower surface of the dielectric substrate, the first unit antenna structure, the second unit antenna structure and the isolation rectangular patch are attached to the upper surface of the dielectric substrate, and the isolation rectangular patch is arranged between the first unit antenna structure and the second unit antenna structure; the first unit antenna structure comprises a rectangular metal patch and a first feeding microstrip line, and the second unit antenna structure comprises a square fork-shaped metal structure and a second feeding microstrip line; the application arranges the metal ground plate as an isolator, reduces the coupling between the unit antennas, connects the rectangular metal patch to the metal ground plate, realizes the isolation of electromagnetic coupling energy, and simultaneously the microstrip MIMO antenna designed by the application can be applied to satellite data transmission and signal reception.

Description

Technical Field

[0001] This invention belongs to the field of antennas among basic electrical components, and specifically relates to a miniaturized, highly isolated microstrip MIMO antenna with complementary Ku-band structure. Background Technology

[0002] 5G wireless communication technology has high requirements for the coverage of wireless mobile signals. In densely populated cities, the coverage of wireless mobile signals is relatively good, while in rural areas with low population density or in remote mountainous areas, there are often no wireless mobile signals or the coverage of wireless mobile signals is poor.

[0003] Starlink technology can overcome the problem of poor wireless mobile signal coverage and achieve global wireless signal coverage. The way it achieves wireless mobile signal coverage is mainly through satellites, that is, by transmitting wireless signals from satellites to the ground, and ground receiving equipment receives signals with data from satellites, thereby realizing information transmission. Satellites and ground receiving equipment usually use the Ku band to achieve communication.

[0004] As an effective means to improve the data transmission rate between satellites and ground receiving signal equipment, MIMO technology will lead to a broadcast-like increase in the demand for Ku-band MIMO antennas in all wireless mobile communications as the amount of transmitted data increases.

[0005] Chinese patent CN106099335A discloses a low-profile full-band WLAN-MIMO indoor distributed antenna with an orthogonal or circularly distributed radiating body. The antenna consists of a horizontal and vertical dielectric substrate, a reflector, a balun, and a back strip and vibrator fabricated using copper-clad technology. This antenna is a high-gain, miniaturized MIMO antenna capable of covering the entire WLAN frequency band. The antenna's operating band, gain, and directivity are adjusted by changing the relative positions of the back strip and vibrator, and by utilizing the induced capacitance generated by the coupling between the back strip and vibrator. However, because planar antennas have a large main radiation lobe and poor directivity, they are difficult to promote in civilian systems.

[0006] Chinese patent CN109494463A discloses a high-isolation MIMO antenna with a complementary semi-circular structure, comprising a first antenna element and a second antenna element orthogonally arranged on a dielectric substrate. Both antenna elements consist of a semi-circular metal patch and a rectangular metal patch, employing polarization diversity technology to minimize coupling between the two antenna elements, achieving high port isolation. The distance between the two antenna elements is less than one wavelength, thus significantly reducing the size of the MIMO system containing the two antenna elements, achieving miniaturization. However, in array multi-antenna systems, each radiating element has the same structure, preventing structural complementarity and resulting in excessive space occupation.

[0007] Currently, satellites mainly use the sub-6GHz frequency band, while there are few MIMO antennas that can be applied to the Ku band. Therefore, it is particularly important to design a structurally complementary, miniaturized, and highly isolated microstrip MIMO antenna that can be used for satellite data transmission and signal reception. Summary of the Invention

[0008] To address the aforementioned issues, this study aims to design a structurally complementary, miniaturized, and highly isolated microstrip MIMO antenna suitable for satellite data transmission and signal reception, thereby achieving miniaturization and high isolation of the Ku-band antenna structure.

[0009] To achieve the above effects, this invention designs a miniaturized, highly isolated microstrip MIMO antenna with complementary Ku-band structure.

[0010] A Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna includes a first antenna unit structure, a second antenna unit structure, a dielectric substrate, a metal ground plane, and an isolation rectangular patch.

[0011] The metal ground plane is disposed on the lower surface of the dielectric substrate;

[0012] The first unit antenna structure, the second unit antenna structure, and the isolation rectangular patch are attached to the upper surface of the dielectric substrate;

[0013] The isolation rectangular patch is positioned between the first unit antenna structure and the second unit antenna structure.

[0014] Preferably, the first unit antenna structure includes a rectangular metal patch and a first feed microstrip line;

[0015] The first feed microstrip line is located at the center of the lower edge of the rectangular metal patch;

[0016] The geometric center of the rectangular metal patch coincides with the geometric center of the top of the dielectric substrate.

[0017] Preferably, the second unit antenna structure includes a square fork-shaped metal structure and a second feed microstrip line;

[0018] The second power-feeding microstrip line is located at the midpoint of the patch on the upper side of the square fork-shaped metal structure.

[0019] Preferably, the isolation rectangular patch and the dielectric substrate are provided with metallized vias, and the isolation rectangular patch is connected to the metal ground plane at the bottom of the dielectric substrate through the metallized vias.

[0020] Preferably, the square fork-shaped metal structure has an opening structure facing downwards;

[0021] The square fork-shaped metal structure has the same width on all three sides.

[0022] The distance between the left and right sides of the square fork-shaped metal structure and the middle rectangular metal patch is equal.

[0023] The distance between the upper side of the square fork-shaped metal structure and the middle rectangular metal patch is greater than the distance between the left and right sides of the square fork-shaped metal structure and the middle rectangular metal patch.

[0024] Preferably, the outer sides of the left and right metal arms of the square fork-shaped metal structure are provided with grid-like metal patches.

[0025] Preferably, the grid-shaped metal patch includes a first grid-shaped metal patch and a second grid-shaped metal patch;

[0026] The first grid-shaped metal patch is disposed on the left side of the square fork-shaped metal structure;

[0027] The second grid-shaped metal patch is disposed on the right side of the square fork-shaped metal structure.

[0028] Preferably, the grid strips of the first and second grid-shaped metal patches are identical in shape;

[0029] The grid strips of the first and second grid-shaped metal patches are parallelograms.

[0030] Preferably, the grid bars of the first and second grid-shaped metal patches have the same included angle with the edges of the left and right arms of the square fork-shaped metal structure; the included angle is less than 90 degrees.

[0031] The first and second gate-shaped metal patches are mirror-symmetrical about the vertical centerline of the upper surface of the dielectric substrate.

[0032] Preferably, the dielectric substrate is made of polytetrafluoroethylene FR4 with a dielectric constant of 4.4 and a loss tangent of 0.02.

[0033] The metal ground plate is made of copper;

[0034] The materials of the first unit antenna structure, the second unit antenna structure, and the isolation rectangular patch are different from the material of the metal ground plane.

[0035] The advantages and effects of this application are as follows:

[0036] 1. This invention designs a first unit antenna structure and a second unit antenna structure to form a complementary structure, that is, to set two antenna structures in one spatial region. The miniaturization rate of the designed antenna reaches 50±0.5%, which brings the miniaturization of the antenna to the limit.

[0037] 2. This invention uses a metal ground plane as an isolator to reduce coupling between unit antennas; at the same time, this invention adds a rectangular metal patch between the edges of the metal patch portions of the two unit antennas. This rectangular metal patch is connected to the metal ground plane through a metallized via, thereby achieving isolation of electromagnetic coupling energy.

[0038] 3. This application sets a square fork-shaped metal structure outside the second unit antenna structure, and adds two grid-shaped metal patch groups to the outside of the two arms of the second unit antenna structure, which can guide the energy of the second unit antenna to radiate outward and further reduce the energy coupling between units.

[0039] 4. In the two-element microstrip MIMO antenna designed in this application, both element antennas operate using their higher-order resonant points. Higher-order resonant points often have smaller far-field radiation beamwidths, which means that energy is focused and radiated in one direction, making it easy to achieve high-gain far-field radiation.

[0040] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0041] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0043] Figure 1 A top view of a Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna designed in this invention;

[0044] Figure 2 A side view of a Ku-band complementary miniaturized high-isolation microstrip MIMO antenna designed in this invention;

[0045] Figure 3The port network parameters as a function of frequency are obtained from the analysis of the Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna of this invention using three-dimensional electromagnetic simulation software;

[0046] Figure 4 The frequency of port 1 excitation was obtained by analyzing the Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna of this invention using three-dimensional electromagnetic simulation software. f Long-range radiation gain in the direction perpendicular to the antenna plane at 13.0 GHz;

[0047] Figure 5 The frequency at port 2 excitation was obtained by analyzing the Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna of this invention using three-dimensional electromagnetic simulation software. f Long-range radiation gain in the direction perpendicular to the antenna plane at 13.0 GHz;

[0048] Reference numerals: 10, dielectric substrate; 11, second gate-shaped metal patch; 12, rectangular metal patch; 13, first feed microstrip line; 14, second feed microstrip line; 15, square fork-shaped metal structure; 16, first metallized via; 17, first gate-shaped metal patch; 18, second metallized via; 19, isolation rectangular patch; 20, metal ground plane. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0050] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0051] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0052] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0053] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0054] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0055] Example 1

[0056] This embodiment mainly introduces the basic design of a Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna.

[0057] A top view of the basic design of a Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna is shown below. Figure 1 As shown, it mainly includes a rectangular dielectric substrate 10, a rectangular metal patch 12 as the first unit antenna structure of the microstrip MIMO antenna, a square fork-shaped metal structure 15 as the second unit antenna structure, and a rectangular isolation patch 19 grounded at both ends. The rectangular dielectric substrate 10 is shared by the two unit antennas. The dielectric substrate is made of polytetrafluoroethylene FR4 with a dielectric constant of 4.4 and a loss tangent of 0.02.

[0058] Different metal structures are etched on both sides of the rectangular dielectric substrate 10 using PCB fabrication technology. The entire lower surface of the rectangular dielectric substrate 10 is covered with copper, serving as a metal ground plane 20.

[0059] Furthermore, a rectangular metal patch 12 is processed at the geometric center of the upper surface of the rectangular dielectric substrate 10, and the geometric center of the rectangular metal patch 12 coincides with the geometric center of the upper surface of the dielectric substrate 10.

[0060] At the center of the lower edge of the rectangular metal patch 12, a first feed microstrip line 13 is fabricated as an antenna feed microstrip line.

[0061] A square fork-shaped metal structure 15 is machined around the rectangular metal patch 12, and the structure is open downwards.

[0062] The square fork-shaped metal structure 15 has three sides of equal width, and the left and right sides are equidistant from the middle rectangular metal patch. The upper side is further away from the middle rectangular metal patch 12, twice the distance between the left and right sides and the middle rectangular metal patch. Between the uppermost metal patch of the square fork-shaped metal structure 15 and the middle rectangular metal patch 12, an isolation rectangular patch 19 with the same length as the middle rectangular metal patch and a width equal to d is fabricated. The two ends of the isolation rectangular patch 19 are connected to the metal ground plane 20 on the back of the dielectric substrate 10 through a first metallized via 16 and a second metallized via 18, forming a metal grounding structure. Near the midpoint of the upper patch of the square fork-shaped metal structure 15, a second feed microstrip line 14 structure is fabricated.

[0063] In addition, two sets of obliquely placed grid-shaped metal patches, the second grid-shaped metal patch 11 and the first grid-shaped metal patch 17, are processed on the outer sides of the left and right metal arms of the square fork-shaped metal structure 15.

[0064] Each group of grid-like metal patches consists of six grid strips, and each patch has the same shape, which is a parallelogram, and they are placed in the same direction.

[0065] The second grid-shaped metal patch 11 and the first grid-shaped metal patch 17 are respectively connected to the left and right arms of the square fork-shaped metal structure 15. The angle between the two sets of obliquely placed grid-shaped metal patches and the edges of the left and right arms of the square fork-shaped metal structure 15 is the same, and the angle formed with the lower side of the edge of the two arms is less than 90 degrees.

[0066] The second grid-shaped metal patch 11 and the first grid-shaped metal patch 17 are mirror-symmetrical about the vertical center line of the upper surface of the dielectric substrate 10.

[0067] When conducting experimental testing on the physical antenna model, the inner cores of the two SMA connectors need to be connected to the first feed microstrip line 13 and the second feed microstrip line 14 near the upper and lower edges of the upper surface of the dielectric substrate 10, respectively. The outer side of the SMA connector is connected to the metal ground plane 20 on the lower surface of the dielectric substrate 10, and then the test can be carried out.

[0068] This invention uses a metal ground plane as an isolator to reduce coupling between unit antennas. At the same time, this invention adds a rectangular metal patch between the edges of the metal patch portions of two unit antennas. This rectangular metal patch is connected to the metal ground plane through a metallized via, thereby achieving isolation of electromagnetic coupling energy.

[0069] This application sets a square fork-shaped metal structure outside the second unit antenna structure, and adds two grid-shaped metal patch groups to the outer sides of the two arms of the second unit antenna structure, which can guide the energy of the second unit antenna to radiate outward and further reduce the energy coupling between units.

[0070] Example 2

[0071] Based on the above embodiment 1, this embodiment mainly introduces the specific design of a Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna.

[0072] A dielectric substrate of polytetrafluoroethylene (PTFE) FR4 with a length L = 70-80 mm, a width W = 70 mm, and a thickness of 1.6 mm was selected as the dielectric substrate for the antenna designed in this invention. PTFE has a dielectric constant of 4.4 and a loss tangent of 0.02. Using circuit board printing technology, copper was deposited on the entire lower surface of the dielectric substrate to form a metal layer of the same size as the lower surface of the dielectric substrate, which serves as the metal ground plane shared by the two antenna elements of the MIMO antenna designed in this invention. Using circuit board etching technology, a copper patch with a length Lp = 29 mm and a width Wp = 17 mm was etched at the geometric center of the upper surface of the dielectric substrate, serving as the radiating structure of the first antenna element.

[0073] At the center of the lower edge of the first unit antenna radiating structure, a width is etched. W A metal patch with e=2mm and length Le=(W-Wp) / 2=(70-17) / 2=26.5mm serves as the microstrip feed line for the first element antenna. Two rectangular metal patches are etched on the outer edges of the rectangular radiating patch of the first element antenna, at a distance d=2.3mm from the radiating patch. The vertical length of each patch is Wp+2*d+Wf=17+2*2.3+3.2=24.8mm, and the width is... W f=3.2mm. On the outer side edge of the rectangular radiating patch of the first unit antenna, at a distance of 2*d=2*2.3mm from the radiating patch, a rectangular metal patch is etched with a length of Lp+2*d=29+2*2.3=33.6mm and a width of Wf=3.2mm. The two vertical metal patches and the horizontal metal patch are connected to form a square fork-shaped metal structure 15, which is the metal radiating structure of the second unit antenna.

[0074] At the midpoint of the upper side edge of the square fork-shaped metal structure 15, a rectangular metal patch with a length of ((W-Wp) / 2)-2*d-Wf=((70-17) / 2)-2*2.3-3.2=18.7mm and a width of 2mm is etched, serving as the feed microstrip line for the second unit antenna. The rectangular feed microstrip line and the square fork-shaped metal structure are connected to form the entire metal structure on the upper surface of the dielectric substrate of the second unit antenna. Outside the two vertical arms of the square fork-shaped metal structure, two sets of grid-like metal patch structures are etched. Each set of grid structures has six grid strips with equal spacing. Each grid strip structure is a parallelogram, with the left and right sides along the vertical direction. The right end of the left grid-like metal patch is connected to the left arm of the square fork-shaped structure, and the upper right corner of the topmost grid strip is connected to the upper left corner of the left arm. The right grid-like metal patch is connected to the right side of the square fork-shaped structure, and the upper left corner of the topmost grid strip is connected to the upper right corner of the right arm. The vertical distance between the six grid bars inside each group of grid-shaped metal patches is 2.5 mm. The other two sides of the grid-shaped metal patch form a 30° angle with the two downward arms of the square fork structure. All patches in the grid-shaped metal patch group are the same size and placed in the same direction, with a vertical side length of 2 mm and a hypotenuse length of 7.1 mm. At the upper end of the rectangular radiating structure of the first unit antenna, a rectangular isolation rectangular patch is etched, with a patch length of Lp=29 mm and a width of d=2.3 mm. Further, at both ends of the rectangular isolation rectangular patch, at a distance from the edges of the rectangular isolation rectangular patch, two first metallized vias 16 and 18 with radii r=d / 2=1.15 mm are machined.

[0075] Furthermore, there is a certain correlation between the metal radiating patches of the first and second unit antennas, but their overall position on the upper surface of the dielectric substrate can be adjusted.

[0076] Furthermore, the angle between the outer edges of the two arms of the square fork-shaped metal radiating structure of the second unit antenna and the grid strips of the metal patch group of the grid structure can be appropriately adjusted within a range of 90°.

[0077] Furthermore, the positions of the two metallized vias can be adjusted appropriately by connecting the midpoints of the left and right sides of the isolation rectangle patch, or the number of metallized vias can be reduced to one.

[0078] Furthermore, the length and width of the shared rectangular dielectric substrate for the two antenna units can be appropriately reduced while maintaining the same thickness.

[0079] When conducting experimental testing on the physical antenna model, the inner cores of the two SMA connectors need to be connected to the two rectangular metal feed structures 13 and 14 near the upper and lower edges of the upper surface of the dielectric substrate 10, respectively. The outer side of the SMA connectors is connected to the metal ground plane 20 on the lower surface of the dielectric substrate 10, and then the test can be carried out.

[0080] This invention designs a first-unit antenna structure and a second-unit antenna structure to form a complementary structure, that is, two antennas are placed in the space of one antenna, that is, two antenna structures are set in one spatial region. The miniaturization rate of the antenna reaches 50±0.5%, and the miniaturization degree of the antenna reaches the limit.

[0081] The two elements of the two-element microstrip MIMO antenna designed in this application operate using their higher-order resonant points. Higher-order resonant points often have smaller far-field radiation lobe widths, which means that energy is focused and radiated in one direction, making it easy to achieve high-gain far-field radiation.

[0082] Example 3

[0083] Based on the above embodiment 2, this embodiment mainly introduces the simulation verification of a Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna.

[0084] Simulation analysis of the high-isolation two-element microstrip MIMO antenna designed in this invention using the three-dimensional electromagnetic simulation software HFSS revealed that, as Figure 3 As shown in the figure, the curve a This graph shows the variation of the reflection coefficient at port 1 of the antenna unit with frequency. b This graph shows the variation of the reflection coefficient at port 2 of the antenna unit with frequency. c This graph shows the energy coupling coefficient between the two ports of antenna unit 1 and antenna unit 2 as a function of frequency. In the 12.75 GHz to 13.07 GHz range, the port reflection coefficients of both antenna units are less than -10 dB, and within this frequency range, such as... Figure 4 , 5 The above, Figure 4 The frequency of port 1 excitation was obtained by analyzing the Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna of this invention using three-dimensional electromagnetic simulation software. f Long-range radiation gain in the direction of the vertical antenna plane at 13.0 GHz. Figure 5 The frequency at port 2 excitation was obtained by analyzing the Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna of this invention using three-dimensional electromagnetic simulation software. f Long-range radiation gain in the direction of the vertical antenna plane at 13.0 GHz.

[0085] The port transmission coefficients of the two antenna elements are less than 15.00 dB. When the first antenna element is port-excited, the antenna gain reaches 8.08 dBi at 13.00 GHz, and when the second antenna element is port-excited, the far-field radiation gain reaches 8.53 dBi at 13.00 GHz. Therefore, the antenna designed in this invention is a Ku-band microstrip two-element microstrip MIMO antenna with complementary structure, high isolation, and high far-field radiation gain. Furthermore, the metal radiating patches of the antenna designed in this invention are all located on a single side of the dielectric substrate, exhibiting unilateral radiation characteristics.

[0086] The above description is merely a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A miniaturized, high-isolation microstrip MIMO antenna with complementary Ku-band structure, characterized in that, It includes a first unit antenna structure, a second unit antenna structure, a dielectric substrate (10), a metal ground plane (20), and an isolation rectangular patch (19); The first unit antenna structure, the second unit antenna structure, and the isolation rectangular patch (19) are attached to the upper surface of the dielectric substrate (10); The isolation rectangular patch (19) is disposed between the first unit antenna structure and the second unit antenna structure; The metal ground plane (20) is disposed on the lower surface of the dielectric substrate (10); The first unit antenna structure includes a rectangular metal patch (12) and a first feed microstrip line (13); The first feed microstrip line (13) is located at the center of the lower edge of the rectangular metal patch (12); The geometric center of the rectangular metal patch (12) coincides with the geometric center of the top of the dielectric substrate (10); The second unit antenna structure includes a square fork-shaped metal structure (15) and a second-fed microstrip line (14); The second feed microstrip line (14) is located at the midpoint of the patch on the upper side of the square fork-shaped metal structure (15); The square fork-shaped metal structure (15) has an opening structure facing downwards; The square fork-shaped metal structure (15) has the same width on all three sides; The distance between the left and right sides of the square fork-shaped metal structure (15) and the middle rectangular metal patch (12) is equal; The distance between the upper side of the square fork-shaped metal structure (15) and the middle rectangular metal patch (12) is greater than the distance between the left and right sides of the square fork-shaped metal structure (15) and the middle rectangular metal patch (12). Metallized vias are provided on the isolation rectangular patch (19) and the dielectric substrate (10), and the isolation rectangular patch (19) is connected to the metal ground plane (20) at the bottom of the dielectric substrate (10) through the metallized vias; The square fork-shaped metal structure (15) has grid-shaped metal patches on the outer sides of its left and right metal arms. The grid-shaped metal patch includes a first grid-shaped metal patch (17) and a second grid-shaped metal patch (11); The grid bars of the first grid-shaped metal patch (17) and the second grid-shaped metal patch (11) have the same angle with the left and right arm edges of the square fork-shaped metal structure (15); the angle is less than 90 degrees.

2. The Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna according to claim 1, characterized in that, The first grid-shaped metal patch (17) is disposed on the left side of the square fork-shaped metal structure (15); The second grid-shaped metal patch (11) is disposed on the right side of the square fork-shaped metal structure (15).

3. The Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna according to claim 2, characterized in that, The first grid-shaped metal patch (17) and the second grid-shaped metal patch (11) have the same grid bar shape; The first grid-shaped metal patch (17) and the second grid-shaped metal patch (11) have parallelogram-shaped grids.

4. A Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna according to any one of claims 1 or 2, characterized in that, The first grid-shaped metal patch (17) and the second grid-shaped metal patch (11) are mirror-symmetrical about the vertical center line of the upper surface of the dielectric substrate (10).

5. The Ku-band structurally complementary miniaturized high-isolation microstrip MIMO antenna according to claim 1, characterized in that, The dielectric substrate (10) is made of polytetrafluoroethylene FR4, with a dielectric constant of 4.4 and a loss tangent of 0.

02. The metal ground plane (20) is made of copper; The materials of the first unit antenna structure, the second unit antenna structure, and the isolation rectangular patch (19) are different from the material of the metal ground plane (20).

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