Multi-band compact 5G MIMO reverse complementary antenna

Abstract

The invention relates to a multi-band compact 5G MIMO reverse complementary antenna. The antenna comprises a PCB main board, a first antenna support and a second antenna support, wherein the first antenna support and the second antenna support are fixed on the PCB main board; the first antenna support is provided with a first antenna and a first grounding coupling branch. The second antenna support is provided with a second antenna and a second grounding coupling branch. Wherein the first antenna and the second antenna are respectively located at two ends of a diagonal line of the PCB mainboard and adopt a bending line structure for routing around one corner of the corresponding first antenna bracket and the second antenna bracket. The antenna unit is composed of two parts, one part is the antenna body connected with the feeder, the other part is the grounding coupling branch, and the grounding coupling branch can generate a new radiation mode to increase the bandwidth of the antenna.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a multi-band compact 5G MIMO reverse complementary antenna. Background Art

[0002] 5G MIMO antenna technology is one of the key technologies in the fifth generation of mobile communications (5G). With the geometric growth of mobile data traffic, wireless communication systems are required to have higher transmission rates, larger bandwidth capacity and lower latency. 5G technology needs to achieve breakthrough innovations in wireless transmission to achieve the goal of increasing spectrum efficiency and power efficiency by more than 10 times. Massive MIMO (massive antenna technology) is a key technology for improving system capacity and spectrum utilization in 5G. It integrates more RF channels and antennas to achieve three-dimensional precise beamforming and multi-stream multi-user multiplexing technology. Massive MIMO technology can provide diversity gain, multiplexing gain and power gain, thereby improving system reliability, supporting single-user spatial multiplexing and multi-user spatial multiplexing, and improving system power efficiency. Beamforming technology is an important part of Massive MIMO. It uses phase control to prevent beams from interfering with each other and accurately points to the service object, thereby improving signal strength, avoiding signal interference, and improving coverage and capacity. 5G antenna technology needs to meet technical features such as high gain, miniaturization, wide frequency band and high isolation to meet the high transmission rate, intelligent beam shaping, beam energy aggregation and other functions of 5G communication. The design and implementation of 5G antennas need to consider how to integrate more antenna elements in a limited space while maintaining the performance of the antenna. 5G communication is oriented to mid- and high-band frequency bands, solving the problem of crowded spectrum resources in low-band frequency bands. The Massive MIMO system, based on array-based multiple-input and multiple-output technology, multiplies the number of base station antennas, thereby greatly improving the communication spectrum efficiency. The challenges faced in 5G network deployment include full-scene coverage and full-space experience. The SSB of Massive MIMO needs to have the accuracy of scene matching and the intelligence of coverage optimization, laying a solid foundation for subsequent experience optimization and value mining.

[0003] In summary, the background technology of 5G MIMO antenna technology involves improving data transmission rate, beamforming technology, the development of antenna technology, optimal utilization of spectrum resources, and network coverage and experience optimization in multiple scenarios. The development and application of these technologies are the basis for improving the performance of 5G communication systems. Among them, if the port isolation and spatial orthogonality of any two combined antennas of the terminal are improved, the rank of the entire transmission matrix H will be improved, and the channel capacity of the communication system can be further increased without increasing the number of antennas and the system operating bandwidth. This topic focuses on improving the isolation and ECC performance between terminal antennas, which is of great significance for improving the system channel capacity and realizing ultra-high-speed 5G transmission. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, optimize the antenna layout based on the field distribution and current distribution of the antenna itself, achieve high performance and high isolation of the antenna, and provide a multi-band compact 5G MIMO reverse complementary antenna.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A multi-band compact 5G MIMO reverse complementary antenna, the antenna comprising:

[0007] PCB motherboard;

[0008] A first antenna bracket and a second antenna bracket fixed on the PCB mainboard;

[0009] The first antenna support is provided with a first antenna and a first ground coupling branch, and the second antenna support is provided with a second antenna and a second ground coupling branch;

[0010] Among them, the first antenna and the second antenna are respectively located at two ends of a diagonal line of the PCB main board and adopt a bending line structure to go around a corner of the corresponding first antenna bracket and the second antenna bracket.

[0011] The antenna unit in this application consists of two parts, one part is the antenna body (first antenna / second antenna) connected to the feed, and the other part is the ground coupling branch, which can generate a new radiation pattern to increase the bandwidth of the antenna. By analyzing the current distribution of the antenna at 1.8GHz, 2.6GHz and high frequency 3.6GHz, it can be seen that the antenna body is the main part that generates the 1.8GHz radiation pattern, and the antenna works in its fundamental mode; in the 2.6GHz frequency band, the antenna radiation mainly becomes the ground coupling branch, and the current on the ground branch is the largest at this time; in the 3.6GHz frequency band, the place where the main antenna has the maximum current has changed from near the 1.8GHz feed point (1 / 4 wavelength current distribution of the antenna body) to the middle of the antenna (1 / 2 wavelength current distribution of the antenna body), indicating that the antenna is now working in the resonance formed by the high-order mode.

[0012] Furthermore, the first ground coupling branch and the second ground coupling branch are used for grounding.

[0013] Furthermore, the PCB mainboard adopts a FR4 substrate with a dielectric constant Dk=4.4 and a loss Df=0.02.

[0014] Furthermore, the first antenna bracket and the second antenna bracket are made of PLA material, with Dk=2.72 and Df=0.0036.

[0015] Furthermore, the first antenna and the second antenna are symmetrical in structure, with an overall height of 8.15 mm and a width of 8.2 mm.

[0016] Furthermore, the distance between the first antenna and the first ground coupling branch and the distance between the second antenna and the second ground coupling branch is 1.8 mm.

[0017] Furthermore, the first antenna bracket and the second antenna bracket are L-shaped.

[0018] Furthermore, a third antenna and a fourth antenna are respectively provided at the corners of the first antenna bracket and the second antenna bracket.

[0019] Furthermore, the first antenna, the second antenna, the third antenna and the fourth antenna correspond to four groups of frequency bands respectively.

[0020] Furthermore, the four frequency bands are 1.71-2.69 GHz, 3.6-3.8 GHz, 0.82-0.96 GHz, and 4.8-5 GHz, respectively.

[0021] The beneficial effects of the present invention are:

[0022] 1. The antenna unit in the present application consists of two parts, one part is the antenna body (first antenna / second antenna) connected to the feeder, and the other part is a ground coupling branch, which can generate a new radiation pattern to increase the bandwidth of the antenna.

[0023] 2. Through the isolation and anti-interference technology based on odd-even mode excitation and circuit network compensation port, the isolation between signals in different frequency bands is greatly improved, and signal interference is effectively reduced. According to experimental data, after adopting this technology, signal interference is reduced and the transmission rate is increased, which significantly improves the stability and reliability of 5G communication in complex multi-band scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of an antenna plane according to an embodiment of the present application;

[0025] Figure 2 This is a schematic diagram of the first antenna area according to an embodiment of the present application;

[0026] Figure 3 This is a schematic diagram of the second antenna area according to an embodiment of the present application;

[0027] Figure 4 This is a schematic diagram of the distribution of the third antenna and the fourth antenna in one embodiment of the present application;

[0028] Figure 5 This is a schematic diagram of antenna return loss simulation according to an embodiment of the present application;

[0029] Figure 6 This is a schematic diagram of antenna efficiency simulation according to an embodiment of the present application;

[0030] Figure 7 This is a schematic diagram of the current distribution of the antenna at 1.8 GHz according to an embodiment of the present application;

[0031] Figure 8 This is a schematic diagram of the current distribution of the antenna at 2.6 GHz according to an embodiment of the present application;

[0032] Fig. 9 Schematic diagram of 3.6 GHz current distribution of an antenna according to an embodiment of the present application

[0033] Fig.10 This is the 1.8 GHz radiation diagram of the antenna according to an embodiment of the present application;

[0034] Fig.11 This is the 2.6GHz radiation diagram of the antenna according to an embodiment of the present application;

[0035] Fig.12 This is the 3.6GHz radiation diagram of the antenna in one embodiment of the present application;

[0036] Fig.13Schematic diagram of the return loss simulation of the whole antenna of the present application embodiment;

[0037] Fig.14 This is a simulation diagram showing the efficiency of the whole antenna of the embodiment of the present application;

[0038] Fig.15 This is a schematic diagram of the simulation of the antenna isolation of the whole device according to the embodiment of the present application;

[0039] Fig.16 The ECC test results of the whole antenna of this application embodiment are as follows:

[0040] Fig.17 This is a schematic diagram of the simulation of the frequency deviation of the whole antenna of the embodiment of the present application. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following.

[0042] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0043] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0044] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0045] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0046] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0047] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0048] The space of handheld terminals is limited. If the coverage of 2 / 3 / 4G antennas is taken into account, the space reserved for 5G MIMO antennas in the terminal will be further compressed. At this time, the distance between MIMO antenna units will be further reduced. For this reason, the port isolation problem will become more prominent. The key to improving the channel capacity of the communication system is to improve the port isolation and spatial radiation orthogonality of the terminal antenna, and the key to improving these two is to utilize the odd and even modes and orthogonal modes of the antenna. Generally speaking, the odd mode requires differential excitation, while the even mode requires common mode excitation. Therefore, two independent feeding structures need to be constructed on the same antenna to achieve effective excitation of the two modes at the same time. In addition, the structure of the antenna needs to be reasonably designed so that its resonant frequency is close under the symmetric boundary of the electric wall and the magnetic wall. The theory of orthogonal mode excitation for antennas of other antenna types, such as patch antennas, is relatively sound. The orthogonal mode excitation of traditional antennas generally relies on the freedom of their two-dimensional structures, while the terminal antennas are often very small (narrow) in a specific dimension. It is difficult to directly realize orthogonal current distribution on the antenna body. At this time, the orthogonal mode excitation must be achieved with the help of the coupling of other surrounding metal units and the constraints of specific boundary conditions. This project draws on the odd-even mode theory in the field of microwave circuits and further applies it to the design of terminal antennas, fully considering the field distribution and current distribution of the antenna in different resonant modes, so that a pair of co-located antennas can work under odd-mode and even-mode excitation conditions respectively. Because the odd-mode and even-mode of the same transmission / radiation structure are independent of each other and do not affect each other, the "mode division multiplexing" of the antenna can be cleverly realized, thereby significantly improving port isolation.

[0049] Further, the coupling between 5G MIMO antenna units can be suppressed from the perspective of spatial waves and far-field radiation patterns, and the envelope correlation coefficient can be reduced. The orthogonality of antenna spatial radiation can be achieved through the layout and type of antennas, or by exciting different modes. For example, by exciting a pair of orthogonal modes of the antenna, a polarization orthogonal radiation pattern can be obtained. In addition, the antenna has a directional pattern under even-mode and odd-mode excitation conditions. Figure 1 Generally, they are end-fire and side-fire, showing complementary characteristics, which can also effectively reduce the envelope correlation coefficient of the antenna. From the perspective of analysis methods, the main focus is on the current distribution and electric field distribution of different antenna modes, because the far field is in a projection relationship with the source; from a design perspective, the key is to choose a suitable feeding structure and feeding method, such as capacitive coupling, microstrip-slot transition and other structures.

[0050] In previous studies on terminal antennas, the electromagnetic compatibility design of antennas is easily overlooked by scholars. However, the electromagnetic compatibility of antennas determines the practicality and reliability of antenna design solutions. Antennas with good electromagnetic compatibility are easy to integrate with actual terminals with complex surrounding acoustic and electrical devices and metal structures. However, an antenna solution with excellent performance in an ideal environment may deteriorate sharply in performance when integrated into a terminal with a more complex actual electromagnetic environment due to poor electromagnetic compatibility. For this reason, the electromagnetic compatibility of antennas will also be the focus of this application.

[0051] refer to Figure 1 and Figure 2 As shown, a multi-band compact 5G MIMO reverse complementary antenna includes a PCB mainboard 101, a first antenna bracket 102 and a second antenna bracket 103 fixed on the PCB mainboard 101; the first antenna bracket 102 is respectively provided with a first antenna 301 and a first ground coupling branch 302, and the second antenna bracket 103 is respectively provided with a second antenna 201 and a second ground coupling branch 202; wherein, the first antenna 301 and the second antenna 201 are respectively located at both ends of a diagonal line of the PCB mainboard 101 and adopt a meander line structure to go around the corresponding first antenna bracket 102 and second antenna bracket 103 corner. The antenna unit in the present application is composed of two parts, one part is the antenna body (first antenna 301 / second antenna 201) connected to the feed, and the other part is the ground coupling branch, which can generate a new radiation pattern to increase the bandwidth of the antenna. By analyzing the current distribution of the antenna at 1.8GHz, 2.6GHz and high frequency 3.6GHz, it can be seen that the antenna body is the main part that produces the 1.8GHz radiation pattern, and the antenna operates in its fundamental mode; in the 2.6GHz frequency band, the antenna radiation mainly becomes the ground coupling branch, and the current on the ground branch is the largest at this time; in the 3.6GHz frequency band, the location where the maximum current appears in the main antenna has changed from near the 1.8GHz feeding point (1 / 4 wavelength current distribution of the antenna body) to the middle of the antenna (1 / 2 wavelength current distribution of the antenna body), indicating that the antenna is now operating in the resonance formed by the high-order mode.

[0052] Optionally, in some embodiments, the first ground coupling branch 302 and the second ground coupling branch 202 are used for grounding.

[0053] Optionally, in some embodiments, the PCB main board 101 adopts an FR4 substrate with a dielectric constant Dk=4.4 and a loss Df=0.02. The first antenna bracket 102 and the second antenna bracket 103 are made of PLA material with Dk=2.72 and Df=0.0036. Furthermore, the first antenna 301 and the second antenna 201 are symmetrical in structure, with an overall height of 8.15 mm and a width of 8.2 mm. Furthermore, the spacing between the first antenna 301 and the first ground coupling branch 302 and the second antenna 201 and the second ground coupling branch 202 is 1.8 mm.

[0054] refer to Figure 5 and Figure 6 As shown in the figure, the return loss of the antenna simulation shows that the antenna operating frequency band can cover the medium and high frequency bands of 1.71-2.69GHz and 3.6-3.8GHz, and the return loss within the band is less than -10dB. The efficiency of the entire frequency band is greater than 87%

[0055] Different from previous antenna designs, this antenna consists of two parts: one is the antenna body connected to the feeder, and the other is a coupling ground branch. The coupling branch can generate a new radiation pattern to increase the bandwidth of the antenna.

[0056] refer to Figure 7-9 As shown in the figure, by analyzing the current distribution of the antenna at 1.8 GHz, 2.6 GHz and high frequency 3.6 GHz, it can be seen that the antenna body is the main part that produces the 1.8 GHz radiation pattern, and the antenna works in its fundamental mode; in the 2.6 GHz band, the antenna radiation mainly becomes a coupled ground branch, and the current on the ground branch is the largest at this time; in the 3.6 GHz band, the location where the maximum current appears in the main antenna has changed from near the 1.8 GHz feeding point (1 / 4 wavelength current distribution of the antenna body) to the middle of the antenna (1 / 2 wavelength current distribution of the antenna body), indicating that the antenna is now working in the resonance formed by the high-order mode.

[0057] refer to Figure 10-12 As shown, the radiation pattern of the antenna shows that the antenna radiation is close to the Omnidirectional radiation form.

[0058] Optionally, in some embodiments, the first antenna support 102 and the second antenna support 103 are L-shaped.

[0059] refer to Figure 3 and Figure 4As shown, further, the third antenna and the fourth antenna are respectively provided at the corners of the first antenna bracket 102 and the second antenna bracket 103. The third antenna and the fourth antenna are symmetrical in structure, wherein the third antenna and the fourth antenna respectively include a first antenna area 401 located outside the short side of the L-shape, and a second antenna area 402 located outside the long side of the L-shape, and the first antenna area 401 and the second antenna area 402 are connected to the L-shaped corner. A slot 404 is formed at the end of the first antenna area 401, thereby increasing the routing length of the antenna, reducing the resonant frequency, and reducing the size of the antenna. The second antenna area 402 is provided with a slot body 403, and the length of the slot body 403 is 15 mm.

[0060] Optionally, in some embodiments, the slot 403 extends to the L-shaped corner and is connected to the first antenna area 401. The length of the first antenna area 401 is less than that of the second antenna area 402 and the height is the same. The length of the first antenna area 401 is 25.7 mm, and the length of the second antenna area 402 is 34.5 mm; the height of the first antenna area 401 and the second antenna area 402 is 6.5 mm. The first antenna, the second antenna, the third antenna, and the fourth antenna correspond to four frequency bands respectively. The four frequency bands are 1.71-2.69 GHz, 3.6-3.8 GHz, 0.82-0.96 GHz, and 4.8-5 GHz, respectively.

[0061] Due to the increase in the frequency bands and number of 5G antennas, it is impossible to achieve high-performance design of all frequency bands through one antenna in a limited space. Reasonable splitting of frequency bands for separate antenna design and arranging antennas in reasonable positions have a significant impact on antenna performance and isolation. Through design, the 5G frequency band is split into four independent antennas (first antenna, second antenna, third antenna and fourth antenna), which are 1.71-2.69GHz and 3.6-3.8GHz, 0.82-0.96GHz, 4.8-5GHz respectively. Each group of frequencies has a separate antenna design implementation. At the same time, each group of frequencies will have two antenna areas to form MIMO to give full play to the performance of 5G. Therefore, this design consists of a total of four antennas. In order to increase the isolation, the four antennas are located at the four corners of the mobile terminal, and the two antennas of the same frequency group are placed at the diagonal to maximize the physical distance and isolation of the same frequency antennas.

[0062] Before the antennas form a MIMO antenna, we also test the performance of the first antenna, the second antenna, the third antenna and the fourth antenna. The -10dB return loss bandwidth of the first antenna and the second antenna can cover the 1.71-2.69GHz and 3.6-3.8GHz frequency bands respectively. The -10dB return loss bandwidth of the third antenna and the fourth antenna can cover the 0.82-0.96GHz and 4.2-5GHz frequency bands respectively, meeting the design requirements.

[0063] The MIMO antennas are arranged at the four corners of the mobile terminal, and the two MIMO antennas with the same frequency are arranged at the diagonal of the mobile terminal, such as the first antenna, the second antenna or the third antenna and the fourth antenna, to maximize the use of the spatial distance of the mobile terminal to reduce interference between antennas. After the MIMO antennas are arranged, compared with single antennas, antennas with poor isolation will affect each other. In the antenna design we use, we reasonably design and arrange the MIMO antennas and take different isolation measures for the MIMO antennas. Different antenna designs are used between the first antenna and the third antenna, or between the second antenna and the fourth antenna, which are closest to each other, and better isolation effects are achieved by taking advantage of their different working modes. Because the first antenna, the second antenna or the third antenna and the fourth antenna are physically separated by a large distance, sufficient isolation performance can be obtained.

[0064] Whole machine antenna simulation reference Figure 13-15 As shown in the figure, the simulation results show that the return loss of all antennas is less than -10dB in the corresponding working frequency band, and the efficiency is higher than 79%, which meets the performance requirements. The isolation between all antennas is greater than 15dB, achieving the expected effect and meeting the isolation performance requirements required for antenna operation.

[0065] refer to Fig.15 As shown in the figure, isolation has a great impact on antenna performance. If the design of a single antenna is good but the isolation is poor, the performance of the antenna will change greatly. For example, the bandwidth of the return loss will not meet the working requirements due to the isolation, the efficiency will deteriorate, and the throughput of the MIMO system will drop significantly, etc. The test results show that the isolation of the MIMO antenna is good, all below -15dB.

[0066] refer to Fig.16 As shown in the figure, ECC is a parameter we focus on. The definition of antenna ECC (Envelop Correlation Coefficient) refers to the correlation between the received signal amplitudes between different antenna units. It is a parameter indicator to measure the diversity performance and coupling performance of MIMO (Multiple Input Multiple Output) multi-antenna systems. The impact of antenna ECC is mainly reflected in the performance of the MIMO system. When the ECC value between multiple antenna units is high, the system will lose the diversity effect, resulting in performance degradation. Therefore, when designing a MIMO system, it is necessary to select an antenna with a lower antenna ECC value to ensure the performance of the system. Usually, when the antenna ECC value is below 0.5, the communication system can operate well.

[0067] There are two ways to calculate ECC, one is based on S parameters, and the other is based on the radiation characteristics of MIMO antennas. The calculation of S parameters is relatively simple and easy to obtain, but the performance evaluation of the MIMO antenna system is not comprehensive enough, and the radiation orthogonality factor of each antenna in the antenna system is not included. Therefore, the second calculation method is very important. In this ECC test, we measured the radiation characteristics of each antenna in a microwave darkroom and used them to calculate ECC. The calculation formula is as follows, where is Field radiation pattern of antenna i (1 or 2):

[0068]

[0069] The results show that the ECC value is below 0.3, which meets the requirements of MIMO applications. Fig.17 As shown, the tested frequency can cover the required frequency band, and the frequency deviation is less than 10%.

[0070] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. A multi-band compact 5G MIMO reverse complementary antenna, characterized in that: The antenna includes: PCB motherboard; A first antenna bracket and a second antenna bracket fixed on the PCB mainboard; The first antenna support is provided with a first antenna and a first ground coupling branch, and the second antenna support is provided with a second antenna and a second ground coupling branch; Among them, the first antenna and the second antenna are respectively located at two ends of a diagonal line of the PCB main board and adopt a bending line structure to go around a corner of the corresponding first antenna bracket and the second antenna bracket.

2. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The first ground coupling branch and the second ground coupling branch are used for grounding.

3. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The PCB main board adopts FR4 substrate, with dielectric constant Dk=4.4 and loss Df=0.

02.

4. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The first antenna bracket and the second antenna bracket are made of PLA material, with Dk=2.72 and Df=0.0036.

5. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The first antenna and the second antenna have symmetrical structures, with an overall height of 8.15 mm and a width of 8.2 mm.

6. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The distance between the first antenna and the first ground coupling branch and the distance between the second antenna and the second ground coupling branch is 1.8 mm.

7. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The first antenna bracket and the second antenna bracket are L-shaped.

8. The multi-band compact 5G MIMO reverse complementary antenna according to claim 7, characterized in that: A third antenna and a fourth antenna are respectively provided at the corners of the first antenna bracket and the second antenna bracket.

9. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The first antenna, the second antenna, the third antenna and the fourth antenna correspond to four frequency bands respectively.

10. The multi-band compact 5G MIMO reverse complementary antenna according to claim 1, characterized in that: The four frequency bands are 1.71-2.69 GHz, 3.6-3.8 GHz, 0.82-0.96 GHz, and 4.8-5 GHz respectively.

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