Multi-band MIMO antenna

Abstract

The invention discloses a multi-band MIMO (Multiple Input Multiple Output) antenna. Comprising a dielectric substrate, a floor, antenna units and a coupling unit, the antenna units and the coupling unit are oppositely arranged on the end face of the dielectric substrate, the floor is located on the outer side of the coupling unit, and the coupling unit is used for reducing coupling among the multiple antenna units; the antenna unit comprises a microstrip line and a radiation patch, the microstrip line is arranged at the edge part of the dielectric substrate and is connected with the radiation patch, and a radiation slot is formed in the radiation patch and is used for increasing the frequency band of the antenna unit. The radiation slot arranged on the radiation patch can increase the frequency band of the antenna unit, so that the antenna can work on a plurality of frequency bands, and the requirements of different communication systems are met. The arrangement of the coupling unit can reduce the coupling among a plurality of antenna units, can improve the isolation of the antenna, enables each antenna unit to work independently, and reduces the mutual interference among the antenna units.

Description

Technical Field

[0001] This application relates to the technical field of antennas, and particularly to a multi-band MIMO antenna. Background Art

[0002] In the era of Internet of Everything, the rapid development of various wireless device terminals has greatly facilitated our daily life. To meet the actual needs of current society, both the communication rate and channel capacity of wireless communication systems need to be significantly improved. In the traditional single-input single-output (SISO) system, the channel capacity is limited. The multi-input multi-output (MIMO) antenna system can achieve the goal of increasing the channel capacity. In the MIMO antenna system, multiple antennas are placed within a limited space, which will cause coupling between different antenna elements, thereby deteriorating the antenna performance. In the MIMO system, the channel capacity is closely related to the number of antennas at the transmitting and receiving ends. When the channels established between the transmitting antennas and the receiving antennas have a small correlation, the more antennas there are, the larger the signal capacity. However, in existing MIMO antennas, it is impossible to cover a wide frequency band within a limited antenna design space, and the coupling between the transceiver ends is strong, which affects the performance of the antenna. Summary of the Invention

[0003] The main technical problem to be solved by this application is to provide a multi-band MIMO antenna, which solves the problems that it is impossible to cover a wide frequency band within a limited antenna design space, and the coupling between the transceiver ends is strong, which affects the performance of the antenna.

[0004] To solve the above technical problem, a technical solution adopted by this application is to provide a multi-band MIMO antenna, including a dielectric substrate, a ground plane, antenna elements, and a coupling unit. The antenna elements and the coupling unit are oppositely arranged on the end face of the dielectric substrate. The ground plane is located outside the coupling unit. There are multiple antenna elements, which are arranged on the dielectric substrate in a polarization diversity manner. The coupling unit is used to reduce the coupling between the multiple antenna elements. The antenna element includes a microstrip line and a radiation patch. The microstrip line is arranged at the edge of the dielectric substrate and is connected to the radiation patch. A radiation slot is opened on the radiation patch, and the radiation slot is used to increase the frequency band of the antenna element.

[0005] In some embodiments, the radiation patch includes a connecting portion and a radiation portion. The connecting portion is connected between the radiation portion and the microstrip line, and the width of the connecting portion is smaller than the width of the microstrip line.

[0006] In some embodiments, the radiation slot includes a first radiation sub-slot, and the first radiation sub-slot is arranged on the radiation portion on one side of the connecting portion.

[0007] In some embodiments, the radiation slot further includes a second radiation sub-slot, which is disposed on the radiation portion on the other side of the connecting portion, and the connecting portion is located between the first radiation sub-slot and the second radiation sub-slot.

[0008] In some embodiments, the first radiation sub-slot is enclosed by the radiation portion, and one end of the second radiation sub-slot penetrates the radiation portion, so that one side of the radiation portion adjacent to the connecting portion has an opening.

[0009] In some embodiments, the antenna unit further includes a resonance ring, which is disposed inside the radiation patch, and the resonance ring is used to increase the resonance frequency of the antenna unit.

[0010] In some embodiments, the ground plane includes a first rectangular portion and a second rectangular portion. The first right angle of the first rectangular portion is aligned with the corner of the dielectric substrate, the second right angle of the first rectangular portion is opposite to the first right angle, and the second rectangular portion extends from the second right angle of the first rectangular portion towards the center of the dielectric substrate.

[0011] In some embodiments, the size of the first rectangular portion is larger than that of the second rectangular portion, and the long sides of the first rectangular portion are parallel to the long sides of the second rectangular portion.

[0012] In some embodiments, the coupling unit includes a central portion and a branch portion. The central portion is disposed at the center position of the dielectric substrate, and the branch portion extends outward from the edge portion of the central portion.

[0013] In some embodiments, the shape of the central portion is circular, the shape of the branch portion is rectangular, the branch portions are evenly distributed outside the central portion, and the outer sides of the branch portions are tangent to the central portion.

[0014] The beneficial effects of the present application are as follows: In the present application, multiple antenna units are arranged on the dielectric substrate in a polarization diversity manner. The polarization diversity technology can effectively reduce the influence of multipath fading on the signal, improve the transmission quality and reliability of the signal; by receiving signals in different polarization directions, the signal diversity can be increased. The radiation slots opened on the radiation patch can increase the frequency band of the antenna unit, enabling the antenna to operate on multiple frequency bands and meet the requirements of different communication systems. The antenna unit and the coupling unit are oppositely arranged on the end face of the dielectric substrate. This layout fully utilizes the space of the dielectric substrate, making the overall structure of the antenna compact and facilitating the realization of the function of a multi-band MIMO antenna in a limited space. The setting of the coupling unit can reduce the coupling between multiple antenna units, improve the isolation of the antenna, enable each antenna unit to operate independently, and reduce the mutual interference between antenna units. The ground plane is located outside the coupling unit, which not only helps with the electromagnetic shielding of the antenna, reduces the influence of external interference on the antenna performance, but also optimizes the radiation pattern of the antenna, improving the radiation efficiency and directivity of the antenna. Description of the Drawings

[0015] Figure 1 is a schematic structural diagram according to an embodiment of the present application;

[0016] Figure 2 is a schematic top view structural diagram according to an embodiment of the present application;

[0017] Figure 3 is a schematic bottom view structural diagram according to an embodiment of the present application;

[0018] Figure 4 is a schematic structural diagram after removing the dielectric substrate according to an embodiment of the present application;

[0019] Figure 5 is a schematic top view structural diagram after removing the dielectric substrate according to an embodiment of the present application;

[0020] Figure 6 is a schematic bottom view structural diagram after removing the dielectric substrate according to an embodiment of the present application;

[0021] Figure 7 is a schematic structural diagram of the ground plane according to an embodiment of the present application;

[0022] Figure 8 is a schematic structural diagram of the radiation patch according to an embodiment of the present application;

[0023] Figure 9 is a schematic structural diagram of the resonant loop according to an embodiment of the present application;

[0024] Figure 10 is a schematic structural diagram of the coupling unit according to an embodiment of the present application;

[0025] Figure 11 is a schematic diagram of S parameters according to an embodiment of the present application;

[0026] Figure 12 is the E-plane radiation pattern at 2.4 GHz according to an embodiment of the present application;

[0027] Figure 13 is the H-plane radiation pattern at 2.4 GHz according to an embodiment of the present application;

[0028] Figure 14 is the E-plane radiation pattern at 5 GHz according to an embodiment of the present application;

[0029] Figure 15 is the H-plane radiation pattern at 5 GHz according to an embodiment of the present application;

[0030] Figure 16 is the E-plane radiation pattern at 6 GHz according to an embodiment of the present application;

[0031] Figure 17 is the H-plane radiation pattern at 6 GHz according to an embodiment of the present application;

[0032] Figure 18 is the E-plane radiation pattern at 7 GHz according to an embodiment of the present application;

[0033] Figure 19 is the H-plane radiation pattern at 7 GHz according to an embodiment of the present application;

[0034] Figure 20 is a line graph of the ECC envelope correlation coefficient according to an embodiment of the present application;

[0035] Figure 21 is a schematic diagram of the peak gain according to an embodiment of the present application. Detailed implementation manners

[0036] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly disposed on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component.

[0038] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "perpendicular", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the indicated device or component must have a specific orientation, be constructed and operated in a specific orientation, so it should not be construed as a limitation on the present application.

[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, the meaning of "a plurality" and "several" is two or more, unless otherwise specifically defined.

[0040] It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the implementation conditions of the present application. Therefore, they do not have technical substantial significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present application can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present application.

[0041] Figures 1 - 21 An embodiment of a multi-band MIMO antenna of the present application is shown, including a dielectric substrate 1, a ground plane 2, antenna elements 3 and a coupling unit 4. The antenna elements 3 and the coupling unit 4 are oppositely arranged on the end face of the dielectric substrate 1. The ground plane 2 is located outside the coupling unit 4. A plurality of antenna elements 3 are provided and arranged on the dielectric substrate 1 in a polarization diversity manner. The coupling unit 4 is used to reduce the coupling between the plurality of antenna elements 3. The antenna element 3 includes a microstrip line 31 and a radiation patch 32. The microstrip line 31 is arranged at the edge of the dielectric substrate 1 and is connected to the radiation patch 32. A radiation slot 321 is formed on the radiation patch 32, and the radiation slot 321 is used to increase the frequency band of the antenna element 3.

[0042] In this application, multiple antenna units 3 are arranged on the dielectric substrate 1 in a polarization diversity manner. The polarization diversity technology can effectively reduce the impact of multipath fading on signals, improve the transmission quality and reliability of signals, and increase the signal diversity by receiving signals in different polarization directions. The radiation slots 321 opened on the radiation patch 32 can increase the frequency band of the antenna unit 3, enabling the antenna to operate on multiple frequency bands and meet the requirements of different communication systems. The antenna unit 3 and the coupling unit 4 are oppositely arranged on the end face of the dielectric substrate 1. This layout fully utilizes the space of the dielectric substrate 1, making the overall antenna structure compact and facilitating the realization of the functions of a multi-band MIMO antenna in a limited space. The setting of the coupling unit 4 can reduce the coupling between multiple antenna units 3, improve the isolation of the antenna, enable each antenna unit 3 to operate independently, and reduce the mutual interference between antenna units 3. The ground plane 2 is located outside the coupling unit 4, which not only helps with the electromagnetic shielding of the antenna, reduces the impact of external interference on the antenna performance, but also optimizes the radiation pattern of the antenna, improving the radiation efficiency and directivity of the antenna.

[0043] In some embodiments, as Figures 1 - 3 shown, the shape of the dielectric substrate 1 can be square, rectangular, regular polygon, etc. In this application, a square is taken as an example for illustration. The material of the dielectric substrate 1 can be a laminate of ceramic / hydrocarbon, with a dielectric constant of 3.66. The side length of the dielectric substrate 1 is 50 mm to 70 mm, and the thickness is 1 mm to 3 mm. Further, the side length of the dielectric substrate 1 is 62 mm, and the thickness is 1.524 mm.

[0044] In some embodiments, as Figure 3 shown, there are four ground planes 2, which are respectively located at the four corners of the dielectric substrate 1. The ground plane 2 includes a first rectangular portion 21 and a second rectangular portion 22. The first right angle Z1 of the first rectangular portion 21 is aligned with the corner of the dielectric substrate 1, the second right angle Z2 of the first rectangular portion 21 is opposite to the first right angle Z1, and the second rectangular portion 22 extends from the second right angle Z2 of the first rectangular portion 21 towards the center of the dielectric substrate 1. This can reduce the size of the ground plane 2 and further reduce the coupling in the antenna unit 3.

[0045] In some embodiments, as Figure 7 shown, the size of the first rectangular portion 21 is larger than that of the second rectangular portion 22, and the long sides of the first rectangular portion 21 and the second rectangular portion 22 are parallel.

[0046] In some embodiments, as Figure 7 shown, the length L1 of the first rectangular portion 21 is 7 mm to 10 mm, and the width W1 is 5 mm to 8 mm; the length L2 of the second rectangular portion 22 is 5 mm to 8 mm, and the width W2 is 2 mm to 5 mm.

[0047] Furthermore, the length L1 of the first rectangular portion 21 is 8.58 mm, the width W1 is 6 mm, the length L2 of the second rectangular portion 22 is 6.5 mm, and the width W2 is 3.99 mm.

[0048] In some embodiments, as Figures 3 - 6 shown, four antenna units 3 are provided. The four antenna units 3 are arranged at the four corners of the dielectric substrate 1 and are arranged in a mutually orthogonal manner. That is, a circular array is performed with the central vertical line of the dielectric substrate 1 as the center. Thereby, the coupling between the four antenna units 3 can be reduced, and the polarization orthogonality between the antenna units 3 can be achieved. Thus, the coupling between the antenna units 3 is reduced while realizing a compact layout of the antenna.

[0049] In some embodiments, the outer end of the microstrip line 31 is flush with the side edge of the dielectric substrate 1, and the inner end of the microstrip line 31 extends toward the inside of the dielectric substrate 1 and is connected to the radiation patch 32.

[0050] In some embodiments, as Figure 8 shown, the structure of the microstrip line 31 is rectangular. The long side of the microstrip line 31 extends toward the inside of the dielectric substrate 1. One short side of the microstrip line 31 is collinear with the side edge of the dielectric substrate 1, and the other short side of the microstrip line 31 is connected to the radiation patch 32.

[0051] The radiation patch 32 includes a connection portion 322 and a radiation portion 323. The connection portion 322 is connected between the radiation portion 323 and the microstrip line 31. The connection portion 322 is rectangular, and the width of the connection portion 322 is smaller than the width of the microstrip line 31.

[0052] In some embodiments, as Figure 8 shown, the length L3 of the microstrip line 31 is 4 mm to 8 mm, and the width W3 of the microstrip line 31 is 2 mm to 5 mm.

[0053] Furthermore, the length L3 of the microstrip line 31 is 6 mm, and the width W3 of the microstrip line 31 is 3.4 mm.

[0054] The shape of the radiation portion 323 can be circular, square, rectangular, or regular polygon, etc. Thereby, the current path can be increased.

[0055] In some embodiments, the radiation slot 321 can play a role in adjusting the frequency band and impedance matching. The radiation slot 321 includes a first radiation sub-slot 3211. The first radiation sub-slot 3211 is provided on the radiation portion 323 on one side of the connection portion 322. Through the first radiation sub-slot 3211, the operating frequency band of the antenna unit 3 can be adjusted to achieve an operating frequency band covering 2.36 GHz - 2.54 GHz and 4.69 GHz - 8.17 GHz. It includes 2.4 GHz, 5 GHz, 6 GHz, and 7 GHz in the WIFI7 frequency band.

[0056] In some embodiments, the radiation slot 321 further includes a second radiation sub-slot 3212, and the second radiation sub-slot 3212 is disposed on the radiation portion 323 on the other side of the connecting portion 322, that is, the connecting portion 322 is located between the first radiation sub-slot 3211 and the second radiation sub-slot 3212. The working frequency band of the antenna unit 3 can be further adjusted by the second radiation sub-slot 3212.

[0057] In some embodiments, the first radiation sub-slot 3211 is surrounded by the radiation portion 323, and one end of the second radiation sub-slot 3212 penetrates the radiation portion 323, so that the side of the radiation portion 323 adjacent to the connecting portion 322 has an opening.

[0058] In some embodiments, the length of the first radiation sub-slot 3211 is less than the length of the second radiation sub-slot 3212, and the width of the first radiation sub-slot 3211 is greater than the width of the second radiation sub-slot 3212.

[0059] In some embodiments, the radiation portion 323, the first radiation sub-slot 3211, and the second radiation sub-slot 3212 are all rectangular. The radiation portion 323 includes a first included angle J1, a second included angle J2, and a third included angle J3. The first included angle J1 is located between the second included angle J2 and the third included angle J3. The second included angle J2 and the third included angle J3 are oppositely arranged. The first included angle J1 is connected to the connecting portion 322. The first radiation sub-slot 3211 is adjacent to the second included angle J2, and the second radiation sub-slot 3212 is adjacent to the third included angle J3.

[0060] In some embodiments, as Figure 8 shown, the length L4 of the radiation portion 323 is 20 mm to 40 mm, the width W4 is 4 mm to 8 mm, the length L5 of the first radiation sub-slot 3211 is 10 mm to 20 mm, the width W5 is 1 mm to 3 mm, the length L6 of the second radiation sub-slot 3212 is 10 mm to 30 mm, and the width W6 is 0.5 mm to 2 mm.

[0061] Further, the length L4 of the radiation portion 323 is 29 mm, the width W4 is 6 mm, the length L5 of the first radiation sub-slot 3211 is 16.24 mm, the width W5 is 1.29 mm, the length L6 of the second radiation sub-slot 3212 is 17.27 mm, and the width W6 is 0.78 mm.

[0062] In some embodiments, the antenna unit 3 further includes a resonance ring 33, and the resonance ring 33 is disposed inside the radiation patch 32. The resonance ring 33 is used to increase the resonance frequency of the antenna unit 3.

[0063] In some embodiments, the resonant loop 33 has an annular structure such as a square, a rectangle, or a regular polygon. An opening 331 is provided on a side of the resonant loop 33 away from the radiation patch 32. By providing the resonant loop 33, a new resonant frequency can be added to the antenna element 3, improving the frequency band coverage of the antenna element 3.

[0064] In some embodiments, as Figure 9 shown, the side length L7 of the resonant loop 33 is 3 mm to 8 mm, the size L8 of the opening 331 is 1 to 3 mm. The loop width W7 of the resonant loop 33 is 0.5 mm to 2 mm. The dimension W8 extending from the opening 331 is 0.5 mm to 2 mm.

[0065] Further, the side length L7 of the resonant loop 33 is 5.5 mm, the size L8 of the opening 331 is 1.5 mm. The loop width W7 of the resonant loop 33 is 1 mm. The dimension W8 extending from the opening 331 is 1 mm.

[0066] In some embodiments, the coupling unit 4 includes a central portion 41 and a branch portion 42. The central portion 41 is disposed at the center of the dielectric substrate 1, and the branch portion 42 extends outward from the edge of the central portion 41. This can further reduce the coupling in the antenna element 3, improve the isolation of the antenna, and reduce the mutual interference between the antenna elements 3.

[0067] In some embodiments, the shape of the central portion 41 can be a circle, a rectangle, or a polygon, etc. The shape of the branch portion 42 can be an ellipse, an arc, or a rectangle, etc.

[0068] In some embodiments, the shape of the central portion 41 is a circle, and the shape of the branch portion 42 is a rectangle. The branch portions 42 are evenly distributed outside the central portion 41, and the outer edges of the branch portions 42 are tangent to the central portion 41. This can guide the current to the central portion 41 without flowing to the antenna element 3.

[0069] In some embodiments, as Figure 10 shown, the radius R1 of the central portion 41 is 5 mm to 20 mm, the length L9 of the branch portion 42 is 15 mm to 30 mm, and the width W9 is 4 mm to 10 mm.

[0070] Further, the radius R1 of the central portion 41 is 12.13 mm, the length L9 of the branch portion 42 is 23.13 mm, and the width W9 is 6.23 mm.

[0071] In some embodiments, as Figure 11 shown, Figure 11 the abscissa is the frequency (Frep), and the ordinate is the gain. Figure 11The scattering parameters (S-parameters) of the antenna are shown, where S11 is the return loss of the antenna at port 1, and S21, S31, and S41 are the coupling coefficients between ports 2, 3, and 4 of the antenna, respectively. From Figure 11 The S11 shows that the antenna has good impedance matching in the operating frequency band and good isolation coefficients within the frequency bands of different ports.

[0072] In some embodiments, as Figures 12 - 19 shown, Figures 12 - 19 it shows the E-plane pattern and H-plane pattern at 2.4 GHz, 5 GHz, 6 GHz, and 7 GHz respectively. From Figures 12 - 19 it can be seen that the present application has good radiation patterns at 2.4 GHz, 5 GHz, 6 GHz, and 7 GHz.

[0073] In some embodiments, as Figure 20 shown, ECC is the envelope correlation coefficient, ECC21 is the envelope correlation coefficient between the first antenna element and the second antenna element. ECC31 is the envelope correlation coefficient between the first antenna element and the third antenna element. ECC41 is the envelope correlation coefficient between the first antenna element and the fourth antenna element. From Figure 20 it can be seen that the antenna has good diversity ability.

[0074] In some embodiments, as Figure 21 shown, from Figure 21 it can be seen that the antenna has good gain in the operating frequency band.

[0075] It can be seen that the present application discloses a multi-band MIMO antenna. In the present application, multiple antenna elements are arranged on the dielectric substrate in a polarization diversity manner. The polarization diversity technology can effectively reduce the influence of multipath fading on the signal, improve the transmission quality and reliability of the signal; by receiving signals in different polarization directions, the diversity of the signal can be increased. The radiation slots opened on the radiation patch can increase the frequency band of the antenna element, enabling the antenna to operate on multiple frequency bands and meet the requirements of different communication systems. The antenna element and the coupling unit are oppositely arranged on the end face of the dielectric substrate. This layout fully utilizes the space of the dielectric substrate, making the overall structure of the antenna compact and facilitating the realization of the function of the multi-band MIMO antenna in a limited space. The setting of the coupling unit can reduce the coupling between multiple antenna elements, improve the isolation of the antenna, enable each antenna element to work independently, and reduce the mutual interference between antenna elements. The ground plane is located outside the coupling unit, which not only helps with the electromagnetic shielding of the antenna, reduces the influence of external interference on the antenna performance, but also optimizes the radiation pattern of the antenna, improves the radiation efficiency and directivity of the antenna.

[0076] The above are only the embodiments of the present application, and do not limit the patent scope of the present application accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A multi-band MIMO antenna, characterized in that, It includes a dielectric substrate, a ground plane, antenna elements and a coupling unit. The antenna elements and the coupling unit are oppositely arranged on the end face of the dielectric substrate. The ground plane is located outside the coupling unit. A plurality of antenna elements are provided and arranged on the dielectric substrate in a polarization diversity manner. The coupling unit is used to reduce the coupling between the plurality of antenna elements. The antenna element includes a microstrip line and a radiation patch. The microstrip line is arranged at the edge of the dielectric substrate and connected to the radiation patch. A radiation slot is formed on the radiation patch, and the radiation slot is used to increase the frequency band of the antenna element.

2. The multi-band MIMO antenna according to claim 1, wherein The radiation patch includes a connecting part and a radiation part. The connecting part is connected between the radiation part and the microstrip line, and the width of the connecting part is smaller than the width of the microstrip line.

3. The multi-band MIMO antenna according to claim 2, wherein The radiation slot includes a first radiation sub-slot, and the first radiation sub-slot is arranged on the radiation part on one side of the connecting part.

4. A multi-band MIMO antenna according to claim 3, characterized in that, The radiation slot further includes a second radiation sub-slot, and the second radiation sub-slot is arranged on the radiation part on the other side of the connecting part. The connecting part is located between the first radiation sub-slot and the second radiation sub-slot.

5. A multi-band MIMO antenna according to claim 4, wherein, The first radiation sub-slot is enclosed by the radiation part. One end of the second radiation sub-slot penetrates the radiation part, so that one side of the radiation part adjacent to the connecting part has an opening.

6. The multi-band MIMO antenna according to claim 1, characterized in that The antenna element further includes a resonance ring, and the resonance ring is arranged inside the radiation patch. The resonance ring is used to increase the resonance frequency of the antenna element.

7. A multi-band MIMO antenna according to claim 1, characterized in that, The ground plane includes a first rectangular part and a second rectangular part. The first right angle of the first rectangular part is aligned with the corner of the dielectric substrate. The second right angle of the first rectangular part is opposite to the first right angle. The second rectangular part extends from the second right angle of the first rectangular part towards the center of the dielectric substrate.

8. A multi-band MIMO antenna according to claim 7, characterized in that, The size of the first rectangular part is larger than the size of the second rectangular part, and the long sides of the first rectangular part and the second rectangular part are parallel.

9. The multi-band MIMO antenna according to claim 1, characterized in that The coupling unit includes a central part and a branch part. The central part is arranged at the central position of the dielectric substrate, and the branch part extends outward from the edge of the central part.

10. A multi-band MIMO antenna according to claim 9, characterized in that, The shape of the central part is circular, the shape of the branch part is rectangular, the branch parts are evenly distributed outside the central part, and the outer sides of the branch parts are tangent to the central part.

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