A multiple-input multiple-output antenna array

Abstract

The present invention discloses a multi-input multi-output antenna array, comprising a plurality of antenna units, and the plurality of antenna units are evenly divided into two mutually symmetrical rows of arrays printed on a substrate, and the plurality of antenna units in each single row are also arranged in a central symmetrical manner, and when one of the antenna units is excited, the other antenna units will be connected to a 50Ω load; each antenna unit is composed of an annular radiating element and a U-shaped groove, the inner surface of the side substrate is provided with a T-shaped feed line for feeding, and one side of the T-shaped feed line is provided with a feed line for adjusting the impedance matching of the antenna, the annular radiating elements are distributed on the outer surface of the vertical side substrate, and the U-shaped groove is provided on the ground plane of the main substrate, so that the resonance modes overlap with each other, thereby widening the bandwidth of the antenna unit; the multi-mode overlapping antenna unit structure proposed in the present invention is used to form an antenna array, has the performance of broadband and good isolation, and meets the development needs of mobile terminal antennas.

Description

Technical Field

[0001] The present invention belongs to the technical field of array antennas, and in particular relates to a multi-input multi-output antenna array. Background Art

[0002] The key technologies of 5G mobile communication systems are to increase channel capacity, data transmission rate and spectrum utilization. MIMO (Multiple-Input Multiple-Output) technology can effectively utilize spatial resources to increase channel capacity and antenna transmission efficiency. MIMO technology uses multiple transmitting antennas and receiving antennas and utilizes the multipath effect of the channel to achieve mutual independence of signals, thereby greatly improving channel capacity and quality, and can also effectively solve the problem of information transmission requirements for wireless communication big data.

[0003] Antenna bending technology is a common method to improve the working bandwidth of the antenna. This technology increases the current length within a limited area through bending, thereby reducing the space occupied by the antenna. At the same time, the structure after bending sometimes also produces multi-mode resonance characteristics.

[0004] When designing the broadband characteristics of antennas, the electromagnetic coupling effect needs to be considered. The transmission of surface waves is an important factor affecting antenna coupling, and the surface current on the floor will also cause surface waves to affect the mutual coupling between antennas. In order to improve the isolation between antenna units, a defective ground structure (DGS) is generally used. It aims to load gaps on the floor, and block the surface current of the floor from flowing into the input and output ports of the MIMO system through the gaps, greatly reducing the current flowing from one side of the ground to the other side, thereby reducing the mutual coupling between the two antenna units.

[0005] The main technical defects at present: There are two main technologies for widening the bandwidth of 12×12 MIMO antenna array. One is antenna bending technology, but the complexity of antenna structure will increase and the processing error must be small. The other is defective ground structure, but this structure will occupy a large space and is suitable for mobile device systems with smaller space requirements. Summary of the invention

[0006] The object of the present invention is to provide a multi-input multi-output antenna array to solve the problems raised in the above background technology.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a multi-input and multi-output antenna array, comprising a plurality of antenna units, and the plurality of antenna units are evenly divided into two mutually symmetrical rows of arrays printed on a substrate, and the plurality of antenna units in each single row are also arranged in a centrally symmetrical manner, and when one of the antenna units is excited, the other antenna units will be connected to a 50Ω load.

[0008] Preferably, the substrate comprises a main substrate and a side substrate, the side substrates are symmetrically connected to both side edges of the main substrate, and the main substrate and the side substrates are perpendicular.

[0009] Preferably, each antenna unit is composed of an annular radiating element and a U-shaped groove, the inner surface of the side substrate is provided with a T-shaped feed line for feeding, and one side of the T-shaped feed line is provided with a feed line for adjusting the impedance matching of the antenna, the annular radiating elements are distributed on the outer surface of the vertical side substrate, and the U-shaped groove is arranged on the ground surface of the main substrate, so that the resonant modes overlap with each other and widen the bandwidth of the antenna unit.

[0010] Preferably, the materials of the main substrate and the side substrate are both FR-4, ε r =4.4, tanδ=0.02, and the thickness is 0.8mm.

[0011] Preferably, one end of the feeder line close to the T-shaped feeder line is a short-circuit line, the height of the short-circuit line is 3 mm, and the width is 5 mm. A feeding point is arranged at the other end of the feeder line.

[0012] Preferably, the length of the annular radiation element is 13 mm, and the width is 5.5 mm. A rectangular short branch line is also provided on the inner side of the annular radiation element, and the length of the rectangular short branch line is 3.25 mm, and the width is 0.5 mm.

[0013] Preferably, the overall width of the U-shaped groove is 3 mm, wherein the length of the long arm end is 15 mm and the width is 0.5 mm; the length of the short arm end is 13 mm and the width is 0.8 mm.

[0014] Compared with the prior art, the beneficial effects of the present invention are: the multi-mode overlapping antenna unit structure proposed in the present invention is used to form an antenna array, which has broadband and good isolation performance, and meets the development needs of mobile terminal antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0016] Figure 2 It is a schematic diagram of the unfolded structure of a single antenna unit of the present invention;

[0017] Figure 3 It is a schematic diagram of the structure in which the T-shaped feeder lines of the present invention are distributed on the side substrate;

[0018] Figure 4 It is a schematic diagram of the structure in which the annular radiation elements of the present invention are distributed on the side substrate;

[0019] Figure 5It is a schematic diagram of the arrangement and distribution of the feeder lines on the main substrate of the present invention;

[0020] Figure 6 It is a schematic diagram of the arrangement and distribution of the U-shaped grooves on the grounding surface of the main substrate of the present invention;

[0021] Figure 7 A schematic diagram of a 12×12 MIMO antenna array in an embodiment of the present invention;

[0022] Figure 8 is a schematic diagram of the reflection coefficient of the antenna array of the present invention;

[0023] Fig. 9 is a schematic diagram of the transmission coefficient of the antenna array of the present invention;

[0024] Fig.10 is the voltage standing wave ratio coefficient of the antenna array of the present invention;

[0025] Fig.11 is a schematic diagram of the envelope correlation coefficient of the antenna array of the present invention;

[0026] Fig.12 is a schematic diagram of diversity gain of the antenna array of the present invention;

[0027] Fig.13 and Fig.14 is the far-field radiation pattern of the antenna unit 1 in the embodiment at 3.36 GHz and 3.6 GHz;

[0028] Fig.15 and Fig.16 is the far-field radiation pattern of the antenna unit 2 in the embodiment at 3.36 GHz and 3.6 GHz;

[0029] Fig.17 and Fig.18 is the far-field radiation pattern of the antenna unit 3 at 3.36 GHz and 3.6 GHz in the embodiment;

[0030] In the figure: 1. Main substrate; 2. Side substrate; 3. T-shaped feeder line; 4. Ring radiating element; 5. Feeder line; 6. U-shaped slot; 7. Feeding point. DETAILED DESCRIPTION

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

[0032] See also Figure 1 and Fig.18 The present invention provides a technical solution: a multi-input multi-output antenna array, including multiple antenna units, and the multiple antenna units are evenly divided into two symmetrical rows of arrays printed on a substrate, and the multiple antenna units in each single row are also arranged symmetrically. In this embodiment, preferably, the substrate includes a main substrate 1 and a side substrate 2, the side substrate 2 is symmetrically connected to the two side edges of the main substrate 1, and the main substrate 1 and the side substrate 2 are vertical. The materials of the main substrate 1 and the side substrate 2 are FR-4, εr = 4.4, tanδ = 0.02, and the thickness is 0.8mm; In this embodiment, preferably, please refer to Figure 7 , antenna units 1 to 3 and antenna units 4 to 6 are mirror-symmetric about the YOZ plane, and similarly, antenna units 7 to 9 and antenna units 10 to 12 are also mirror-symmetric about the YOZ plane. Antenna units 1 to 6 and antenna units 7 to 12 are mirror-symmetric about the XOZ plane.

[0033] The distance between antenna unit 9 and antenna unit 10 is 9.3 mm, the distance between antenna unit 8 and antenna unit 9 is 6.5 mm, the distance between antenna unit 7 and antenna unit 8 is 12.5 mm, and the distances between antenna unit 7 and antenna unit 12 and the edge of side substrate 2 are both 12.5 mm. The layout of antenna unit 1 to antenna unit 6 is the same as described above.

[0034] In this embodiment, preferably, each antenna unit is composed of an annular radiation element 4 and a U-shaped groove 6, the inner surface of the side substrate 2 is provided with a T-shaped feed line 3 for feeding, and one side of the T-shaped feed line 3 is provided with a feed line 5 for adjusting the impedance matching of the antenna, the annular radiation element 4 is distributed on the outer surface of the vertical side substrate 2, and the U-shaped groove 6 is arranged on the ground surface of the main substrate 1, so that the resonant modes overlap with each other, thereby widening the bandwidth of the antenna unit.

[0035] In this embodiment, preferably, one end of the feeder 5 close to the T-shaped feeder 3 is a short-circuit wire, the height of the short-circuit wire is 3 mm, and the width is 5 mm. The other end of the feeder 5 is provided with a feeding point 7 .

[0036] In this embodiment, preferably, the length of the annular radiation element 4 is 13 mm, and the width is 5.5 mm. A rectangular short branch line is also provided on the inner side of the annular radiation element 4, and the length of the rectangular short branch line is 3.25 mm, and the width is 0.5 mm.

[0037] In this embodiment, preferably, the overall width of the U-shaped groove 6 is 3 mm, wherein the length of the long arm end is 15 mm and the width is 0.5 mm; the length of the short arm end is 13 mm and the width is 0.8 mm.

[0038] Under the above structural parameters, Figure 8 and Fig. 9 It is the S parameter when antenna element 1 is excited and other antenna elements are connected to 50Ω load.

[0039] It can be seen from the reflection coefficient that the two frequency resonance points of the antenna unit partially overlap, thereby widening the -6dB operating bandwidth (3.28GHz-3.68GHz) of the antenna array, and the transmission coefficient is less than -12dB within the operating bandwidth.

[0040] like Fig.10 As shown, it is the voltage standing wave ratio coefficient of the antenna array of the present invention. The frequency range of the voltage standing wave ratio less than 3 is 3.28GHz-3.68GHz, which is well verified. Figure 8 and Fig. 9 -6dB bandwidth in.

[0041] like Fig.11 As shown in Figure 1, within the working frequency band, the ECCs value between any antenna units is less than 0.078. And the diversity gain of the antenna array within the working frequency band is close to 10, as shown in Figure 1. Fig.12 shown.

[0042] As shown Figure 13-Figure 18 As shown, the far-field radiation patterns of antenna unit 1 to antenna unit 3 at 3.36 GHz and 3.6 GHz respectively are described. It can be seen that it almost exhibits omnidirectional radiation characteristics.

[0043] Due to the influence of uncertain factors in the processing and experimental measurement of the antenna array, there are certain differences between the simulation results and the experimental results. However, in general, the measurement results are highly consistent with the simulation results of the designed antenna array, so they can be used as a basis for judging the antenna performance.

[0044] Although the embodiments of the present invention have been shown and described, as detailed above, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multiple-input multiple-output antenna array, characterized in that: It includes multiple antenna units, and the multiple antenna units are evenly divided into two symmetrical rows and printed on a substrate, and the multiple antenna units in each single row are also arranged in a central symmetrical manner. When one of the antenna units is excited, the other antenna units will be connected to a 50Ω load.

2. The multiple-input multiple-output antenna array according to claim 1, characterized in that: The substrate comprises a main substrate (1) and a side substrate (2); the side substrate (2) is symmetrically connected to the two side edges of the main substrate (1); and the main substrate (1) and the side substrate (2) are vertical.

3. The multiple-input multiple-output antenna array according to claim 1, characterized in that: Each antenna unit is composed of an annular radiation element (4) and a U-shaped groove (6); the inner surface of the side substrate (2) is provided with a T-shaped feed line (3) for feeding; one side of the T-shaped feed line (3) is provided with a feed line (5) for adjusting the impedance matching of the antenna; the annular radiation element (4) is distributed on the outer surface of the vertical side substrate (2); the U-shaped groove (6) is provided on the ground plane of the main substrate (1), so that the resonance modes overlap with each other and the bandwidth of the antenna unit is widened.

4. The multiple-input multiple-output antenna array according to claim 2, characterized in that: The main substrate (1) and the side substrate (2) are both made of FR-4, ε r =4.4,tanδ=0.

02.

5. The multiple-input multiple-output antenna array according to claim 3, characterized in that: One end of the feeder line (5) close to the T-shaped feeder line (3) is a short-circuit line, the height of the short-circuit line is 3 mm, and the width is 5 mm. The other end of the feeder line (5) is provided with a feeding point (7).

6. The multiple-input multiple-output antenna array according to claim 3, characterized in that: The annular radiation element (4) has a length of 13 mm and a width of 5.5 mm. A rectangular short branch line is also arranged on the inner side of the annular radiation element (4), and the length of the rectangular short branch line is 3.25 mm and the width is 0.5 mm.

7. The multiple-input multiple-output antenna array according to claim 3, characterized in that: The overall width of the U-shaped groove (6) is 3 mm, wherein the length of the long arm end is 15 mm and the width is 0.5 mm; the length of the short arm end is 13 mm and the width is 0.8 mm.

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