MIMO array antenna

Abstract

The invention discloses an MIMO array antenna, and relates to the technical field of MIMO antennae, and the MIMO array antenna comprises a main dielectric substrate, a metal ground attached to the lower surface of the main dielectric substrate, and at least two antenna pair modules. The antenna pair module is arranged on the upper surface of the main dielectric substrate; the antenna pair module comprises two radiation units with the same shape; the radiation unit adopts a right-angled trapezoidal microstrip patch antenna; the two microstrip patch antennas in the antenna pair module are symmetrically arranged along the bevel edges, and the distance between the two bevel edges is smaller than a preset distance; and a plurality of metal short circuit columns are arranged at the bevel edge of the microstrip patch antenna. The MIMO array antenna designed by the invention has the performance of low profile, high isolation and relatively wide working bandwidth, and can be applied to 5G and 6G mobile communication.

Description

Technical Field

[0001] The present application relates to the technical field of MIMO antennas, and in particular to a MIMO array antenna. Background Art

[0002] In recent years, with the vigorous development of wireless communication technology and users' urgent demand for continuously improving transmission rates, the fifth generation (5G) and sixth generation (6G) mobile communications have attracted attention. Because massive multiple-input multiple-output (MIMO) technology can provide high channel capacity, it is widely used in 5G and 6G wireless communication systems. Traditional 2×2 MIMO antenna systems cannot provide the data throughput required by 5G and 6G wireless communications. Therefore, 8×8 MIMO antenna systems and even 10×10 MIMO antenna systems are the inevitable trend in the development of mobile terminal antenna systems. Due to the limited internal space volume of terminal equipment, as the number of MIMO antenna system units increases, the spacing between radiating units continues to decrease, and the isolation between units also deteriorates rapidly. Therefore, the research on compact antenna pair modules with high isolation is the inevitable development trend for realizing high-performance massive MIMO array antennas. Summary of the Invention

[0003] The purpose of this application is to provide a MIMO array antenna. The designed MIMO array antenna has the performance of low profile, high isolation, and wide operating bandwidth, and can be applied to 5G and 6G mobile communications.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] The present application provides a MIMO array antenna, the MIMO array antenna comprising: a main dielectric substrate, a metal ground, and at least two antenna pair modules;

[0006] The metal ground is attached to the lower surface of the main dielectric substrate; the antenna pair module is arranged on the upper surface of the main dielectric substrate;

[0007] The antenna pair module includes two radiating units of the same shape; the radiating units are right-angled trapezoidal microstrip patch antennas;

[0008] The two microstrip patch antennas in the antenna pair module are symmetrically arranged along the oblique sides, and the distance between the two oblique sides is less than a preset distance;

[0009] A plurality of metal short-circuit posts are arranged at the oblique sides of the microstrip patch antenna; the metal short-circuit posts penetrate the microstrip patch antenna and the main dielectric substrate and are in contact with the metal ground.

[0010] Optionally, a metal short-circuit post is arranged at one end of the upper bottom edge of the microstrip patch antenna and close to the oblique edge.

[0011] Optionally, a straight line formed by all the metal short-circuit posts at the oblique side of the microstrip patch antenna is parallel to the corresponding oblique side.

[0012] Optionally, the metal short-circuit posts at the oblique sides of the microstrip patch antenna are spaced apart at the same distance.

[0013] Optionally, when the number of antenna pair modules is four, the four antenna pair modules are respectively arranged at four corners of the main dielectric substrate, and the four antenna pair modules are symmetrically arranged.

[0014] Optionally, the right-angled sides of the radiation units in the four antenna pair modules coincide with the sides of the main dielectric substrate.

[0015] Optionally, the distance between the metal short-circuit pillars is 2.7 mm, and the distance between a straight line formed by all the metal short-circuit pillars and the corresponding oblique sides is 0.85 mm.

[0016] Optionally, the oblique side spacing between the two microstrip patch antennas in the antenna pair module is 1 mm.

[0017] Optionally, the length of the upper bottom side of the microstrip patch antenna is 17.3 mm, the length of the lower bottom side is 33.3 mm, and the length of the right-angle side is 16 mm.

[0018] Optionally, the main dielectric substrate is made of FR4 material; the metal ground and the antenna pair module are made of metal material.

[0019] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0020] This application provides a MIMO array antenna, which is designed with a right-angled trapezoidal microstrip patch antenna. The two microstrip patch antennas in the same antenna pair module are symmetrically arranged along the hypotenuse, and multiple metal short-circuit posts are arranged along the hypotenuse. The structure of the designed antenna pair module can improve the isolation between radiating elements on the one hand, and the bandwidth of the radiating elements on the other hand. The use of microstrip patch antennas can realize a low-profile MIMO array antenna. Therefore, the MIMO array antenna designed in this application has the performance of low profile, high isolation, and wide operating bandwidth, and can be applied to 5G and 6G mobile communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1A schematic diagram of the structure of a MIMO array antenna provided in an embodiment of the present application;

[0023] Figure 2 A schematic diagram of the location of the metal ground provided in an embodiment of the present application;

[0024] Figure 3 A schematic diagram of the structure of a microstrip patch antenna provided in an embodiment of the present application;

[0025] Figure 4 A schematic diagram of the MIMO array antenna structure with eight antenna pair modules provided in an embodiment of the present application;

[0026] Figure 5 A graph showing how the reflection coefficient varies with frequency, provided in an embodiment of the present application;

[0027] Figure 6 A graph showing the transmission coefficient changing with frequency provided in an embodiment of the present application;

[0028] Figure 7 This is a graph showing how the envelope correlation coefficient varies with frequency, as provided in an embodiment of the present application.

[0029] Reference numerals:

[0030] 1—Main dielectric substrate; 2—Metal ground; 3—Antenna pair module; 4—Radiating element; 5—Metal short-circuit post; 6—Oblique slot; 7—Feed port. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0032] Currently, to cater to users' usage and aesthetic needs, mobile terminal devices are becoming increasingly functionally diverse and thinner in appearance. Therefore, research on low-profile MIMO array antennas is essential. Microstrip patch antennas are a common type of antenna currently used, with the advantages of small size, low profile, low cost, and ease of manufacturing. However, microstrip patch antennas have a narrow bandwidth, and there is a need to effectively increase the operating bandwidth of microstrip patch antennas to apply them to 5G and 6G mobile communications. Therefore, how to design a low-profile, high-isolation microstrip patch antenna pair module that has sufficient operating bandwidth and can meet the various user requirements for mobile terminal antenna systems is one of the current challenges facing 5G and 6G antenna systems.

[0033] In this regard, the present application provides a MIMO array antenna. The designed MIMO array antenna has the performance of low profile, high isolation, and wide operating bandwidth, and can be applied to 5G and 6G mobile communications.

[0034] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] Example

[0036] This application provides a MIMO array antenna, such as Figures 1 to 3 As shown, the MIMO array antenna includes: a main dielectric substrate 1, a metal ground 2 and at least two antenna pair modules 3.

[0037] The metal ground 2 is attached to the lower surface of the main dielectric substrate 1; the antenna pair module 3 is arranged on the upper surface of the main dielectric substrate 1. The main dielectric substrate 1 is made of FR4 material; the antenna pair module 3 and the metal ground 2 are both metal and are printed on the upper and lower surfaces of the main dielectric substrate 1, respectively.

[0038] As an example, for the arrangement of the two antenna pair modules 3 on the main dielectric substrate 1, Figure 1 Randomly select two of the four antenna pair modules shown. Many other arrangements are possible, as long as the distance between the two antenna pair modules maintains good isolation between the ports.

[0039] The antenna pair module 3 includes two radiating units 4 of the same shape; the radiating units 4 are right-angled trapezoidal microstrip patch antennas.

[0040] The two microstrip patch antennas in the antenna pair module 3 are symmetrically arranged along the oblique edges, and the distance between the two oblique edges is less than a predetermined distance (a smaller distance, with an oblique slit 6 separating the two oblique edges). The symmetrical arrangement of the two microstrip patch antennas along the oblique edges can significantly reduce the distance between the two radiating elements 4, effectively reducing the size of the antenna pair module 3.

[0041] like Figure 3 As shown, a plurality of metal short-circuit posts 5 are arranged at the oblique sides of the microstrip patch antenna; the metal short-circuit posts 5 pass through the microstrip patch antenna and the main dielectric substrate 1 and contact the metal ground 2.

[0042] The number of metal short-circuit posts 5 at the oblique sides of the microstrip patch antenna and the distance between the metal short-circuit posts 5 can be changed accordingly, so that the isolation between the two radiating units 4 in the antenna pair module 3 can be flexibly adjusted within a certain range as needed without affecting the antenna operating bandwidth.

[0043] As an optional implementation, in order to improve the performance of the MIMO array antenna, Figure 3 As shown, a metal shorting post 5 can be arranged at the upper bottom edge of the microstrip patch antenna and at one end close to the oblique edge. When the number of metal shorting posts 5 at the oblique edge of the microstrip patch antenna changes and when the distance between the metal shorting posts 5 changes, there is always one metal shorting post 5 fixedly arranged at the upper bottom edge of the radiating element 4.

[0044] As an optional implementation, in order to improve the performance of the MIMO array antenna, the straight line formed by all the metal short-circuit posts 5 at the oblique sides of the microstrip patch antenna may be parallel to the corresponding oblique sides.

[0045] As an optional implementation, in order to improve the performance of the MIMO array antenna, the spacing distances between the metal short-circuit posts 5 at the oblique sides of the microstrip patch antenna can be set to be the same.

[0046] As an optional implementation, when the number of the antenna pair modules 3 is four, the four antenna pair modules 3 are respectively arranged at the four corners of the main dielectric substrate 1 , and the four antenna pair modules are symmetrically arranged.

[0047] As an optional implementation, the right-angled sides of the radiation units 4 in the four antenna pair modules 3 coincide with the sides of the main dielectric substrate 1 .

[0048] Four antenna pair modules 3 together form a MIMO array antenna, and the number of antenna pair modules 3 can be further increased to form a larger-scale MIMO array antenna. For example, if it is set to 8 antenna pair modules 3, Figure 4 As shown, the arrangement of 8 antennas to module 3 is shown. Figure 1 Based on the arrangement of the four antenna pair modules 3 shown, four more antenna pair modules are arranged in the middle area, wherein in each additional antenna pair module 3, the right-angled side of one radiating unit 4 coincides with the edge of the main dielectric substrate 1, and the right-angled side of another radiating unit 4 is arranged relative to the right-angled side of the radiating unit of another additional antenna pair module 4. Figure 4 In the arrangement mode in , the efficiency of the four radiation units 4 in the central area of ​​the main dielectric substrate 1 is lower than that of the other radiation units 4 .

[0049] As an optional implementation, Figure 1 As shown, an 8×8 MIMO array antenna is provided, wherein the size of the metal ground 2 is 150 mm×80 mm; the size of the main dielectric substrate 1 is 150 mm×80 mm×2 mm, the relative dielectric constant is 4.4, and the loss tangent is 0.02.

[0050] The microstrip patch antenna has an upper base length of 17.3 mm, a lower base length of 33.3 mm, and a right-angled side length of 16 mm. The spacing between the hypotenuses of the two microstrip patch antennas in antenna pair module 3 is 1 mm. The designed MIMO array antenna has a cross-sectional height of only 2 mm.

[0051] The distance between the metal short-circuit pillars 5 is 2.7 mm, the distance between the straight line formed by all the metal short-circuit pillars 5 and the corresponding hypotenuse is 0.85 mm, and the radius of each metal short-circuit pillar 5 is 0.4 mm.

[0052] When designing a MIMO array antenna, the first thing to do is to select the feeding method. This application uses a coaxial feeding method to directly feed the radiating unit 4. Secondly, after completing the selection of the feeding method, the antenna needs to have multiple resonant frequencies, that is, the antenna has multiple working modes. At the same time, in order to meet the needs of full-screen mobile phones, the proposed MIMO array antenna has no gaps on the metal ground and has the characteristic of zero clearance. When the metal short-circuit column 5 is not placed, the radiating unit 4 has only one resonant frequency, the bandwidth is relatively narrow, and it cannot fully cover the N79 frequency band, and the isolation between the two radiating units 4 in the antenna pair module 3 is only better than 10dB. When a group of metal short-circuit columns 5 are arranged along the oblique side of the radiating unit 4, the radiating unit 4 adds a resonant frequency, the bandwidth is effectively widened, and it can fully cover the N79 frequency band in 5G mobile communications, and this group of metal short-circuit columns 5 also has a decoupling effect, which can increase the isolation of the antenna to the inside of the module 3 to 20.4dB. Furthermore, in order to reduce the size of the antenna pair module 3 in the mobile phone, the two radiating units 4 are placed symmetrically along the hypotenuse, so that the distance between the two radiating units 4 is greatly reduced, effectively improving the space utilization of the antenna deployment inside the mobile terminal device.

[0053] The antenna in this application directly feeds module 3 using coaxial feeding. Figure 1 、 Figure 3 and Figure 4 The circular ring in the radiating unit 4 is the feeding port 7. After adding a set of metal short-circuit posts 5, the radiating unit 4 forms two resonant frequency points, which can fully cover the N79 frequency band divided in the fifth generation mobile communication. The metal short-circuit posts 5 have a decoupling effect, which can effectively improve the isolation of the antenna from the inside of the module 3. Its various indicators meet the requirements of MIMO antennas. The present application has the characteristics of simple and compact structure, easy manufacturing, low profile and high isolation, which can well meet the current design requirements for mobile terminals.

[0054] In order to prove the performance of the MIMO array antenna designed in this application, the curves of reflection coefficient, transmission coefficient and envelope correlation coefficient of the MIMO array antenna designed in this application varying with frequency are given, as shown in FIG. Figures 5 and 6shown.

[0055] Figure 5 In the figure, the horizontal axis is the frequency and the vertical axis is the reflection coefficient; S ii It is the reflection coefficient of the feeding port i, which indicates the impedance matching of the feeding port. Figure 6 In the figure, the horizontal axis is the frequency and the vertical axis is the transmission coefficient; S ij It is expressed as the transmission coefficient from feed port j to feed port i when feed port i is matched. That is, the energy flowing from feed port i is the energy measured at feed port j. The transmission coefficient of the feed port, that is, the isolation between the radiating elements 4, is used to indicate the degree of mutual influence between the performance of the radiating elements 4 when each radiating element 4 is working. Figure 5 、 Figure 6 The S parameters in the proposed 8×8 MIMO array antenna indicate that within the 4.18GHz-5.15GHz frequency band, the reflection coefficients of all MIMO units (i.e., radiating unit 4) are less than -6dB, and the isolation between MIMO units is greater than 16.8dB. Therefore, the antenna pair module 3 proposed in this application can cover the N79 frequency band designated for fifth-generation mobile communications, while achieving both high isolation and miniaturization.

[0056] Figure 7 In the figure, "antenna i & antenna j" refers to the envelope correlation coefficient between antenna i and antenna j, where antenna i and antenna j refer to two radiating elements 4. In MIMO array antenna design, a low envelope correlation coefficient between MIMO elements indicates that the sub-channels transmitted by the MIMO antennas are more independent of each other and have less mutual influence, thus achieving high channel capacity. The MIMO array antenna proposed in this application has an envelope correlation coefficient of less than 0.1 between each MIMO element in the entire operating frequency band of 4.18 GHz to 5.15 GHz, meeting the requirement of less than 0.5 for mobile terminal devices.

[0057] The beneficial effects of the present application are as follows: First, N (e.g., N=4) antenna pair modules 3 include 2×N radiating units 4. Thanks to the fact that the two right-angled trapezoidal radiating units 4 in the antenna pair module 3 are symmetrically placed along the hypotenuse, the distance between the two radiating units 4 is greatly reduced, effectively improving the space utilization rate of the antenna deployment inside the mobile terminal; Second, the present application can effectively reduce the coupling between the two radiating units 4 in the antenna pair module 3 by arranging a group of metal short-circuit columns 5 along the hypotenuse of the radiating unit 4, so that the isolation of the antenna pair module 3 is better than 20dB in the entire working frequency band; Third, the working frequency band of the present application is 4.18GHz. To 5.15GHz, it can effectively cover the N79 frequency band divided in the fifth generation of mobile communications, and its broadband, high isolation and low profile indicators all meet the communication requirements of MIMO antennas; Fourth, this application has the characteristics of simple and compact structure, easy manufacturing, low processing cost, low profile, high isolation, etc. On the basis of ensuring that the mobile terminal equipment is ultra-thin, it can effectively cover the N79 frequency band divided in the fifth generation of mobile communications, and meet various performance requirements such as high isolation and low envelope correlation coefficient of the MIMO antenna system, and can be used in 5G and 6G mobile terminal MIMO communication applications taking 5G and 6G smartphones as examples.

[0058] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A MIMO array antenna, characterized in that: The MIMO array antenna comprises: a main dielectric substrate, a metal ground and at least two antenna pair modules; The metal ground is attached to the lower surface of the main dielectric substrate; the antenna pair module is arranged on the upper surface of the main dielectric substrate; The antenna pair module includes two radiating units of the same shape; the radiating units are right-angled trapezoidal microstrip patch antennas; The two microstrip patch antennas in the antenna pair module are symmetrically arranged along the oblique sides, and the distance between the two oblique sides is less than a preset distance; A plurality of metal short-circuit posts are arranged at the oblique sides of the microstrip patch antenna; the metal short-circuit posts penetrate the microstrip patch antenna and the main dielectric substrate and are in contact with the metal ground.

2. The MIMO array antenna according to claim 1, wherein: A metal short-circuit column is arranged at one end of the upper bottom edge of the microstrip patch antenna and close to the oblique edge.

3. The MIMO array antenna according to claim 1 or 2, characterized in that: A straight line formed by all the metal short-circuit posts at the oblique side of the microstrip patch antenna is parallel to the corresponding oblique side.

4. The MIMO array antenna according to claim 3, wherein: The spacing distances between the metal short-circuit posts at the oblique sides of the microstrip patch antenna are the same.

5. The MIMO array antenna according to claim 3, wherein: When the number of antenna pair modules is four, the four antenna pair modules are respectively arranged at four corners of the main dielectric substrate, and the four antenna pair modules are symmetrically arranged.

6. The MIMO array antenna according to claim 5, characterized in that: The right-angled sides of the radiation units in the four antenna pair modules coincide with the sides of the main dielectric substrate.

7. The MIMO array antenna according to claim 3, wherein: The distance between the metal short-circuit pillars is 2.7 mm, and the distance between the straight line formed by all the metal short-circuit pillars and the corresponding oblique side is 0.85 mm.

8. The MIMO array antenna according to claim 1, wherein: The distance between the oblique sides of the two microstrip patch antennas in the antenna pair module is 1 mm.

9. The MIMO array antenna according to claim 1, wherein: The length of the upper bottom side of the microstrip patch antenna is 17.3 mm, the length of the lower bottom side is 33.3 mm, and the length of the right-angle side is 16 mm.

10. The MIMO array antenna according to claim 4, wherein: The main dielectric substrate is made of FR4 material; the metal ground and the antenna pair module are made of metal material.

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