A self-decoupling high isolation MIMO mobile phone antenna

Abstract

The present invention discloses a self-decoupling high-isolation MIMO mobile phone antenna, which includes a substrate, antenna elements, a feeding unit, a coaxial feeder, and a ground plane. The substrate is composed of a bottom horizontal substrate and two side vertical substrates; the antenna elements are composed of convex-shaped metal patches and are located outside the side substrates; the convex-shaped metal patches are symmetrically composed of a first rectangle, a second rectangle, a third rectangle, and a fourth rectangle connected in sequence; the feeding unit is composed of a T-shaped metal patch on the side substrate and a rectangular metal patch on the bottom horizontal substrate, and the T-shaped metal patch is located inside the side substrate and is composed of a fifth rectangle and a sixth rectangle connected; the ground plane is printed on the back of the bottom horizontal substrate; the antenna provided by the present invention changes the structure of the antenna elements, enabling the antenna elements to achieve self-decoupling, greatly improving the isolation between the antenna elements, and covering the 5G 3.3 GHz - 3.6 GHz frequency band, solving the problems of complex decoupling methods and low isolation in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas, and specifically to a self-decoupling high-isolation MIMO mobile phone antenna. Background Art

[0002] With the continuous improvement of people's demand for the channel capacity and spectrum utilization efficiency of mobile communication systems, higher requirements are put forward for the antenna performance of 5G mobile terminals. Therefore, the research on such antennas has received great attention. Currently, the 2×2 MIMO antenna system used for 4G LTE (Long Term Evolution) wireless communication has been widely applied to mobile terminals. However, for 5G wireless communication, the 2×2 MIMO system cannot meet its data transmission rate. Compared with the 4G MIMO antenna system, the 5G MIMO mobile terminal needs to integrate at least six antenna elements.

[0003] When the number of antennas operating in the same frequency band is larger, the resulting problems are the isolation problem between each antenna element and the miniaturization problem of each antenna element. Therefore, the miniaturization design of antenna elements and how to solve the number of MIMO antennas and the isolation degree of antenna elements are important links in 5G antenna design. In the current design of MIMO mobile phone antennas, most of their designed isolation degrees are lower than -15 dB, and there is still a shortage in terms of high isolation. In the current design of MIMO mobile phone antennas, the decoupling methods mostly used in the design include neutralization lines, defected ground structures, polarization diversity, etc., which are relatively complex. Summary of the Invention

[0004] The purpose of the present invention is to provide a self-decoupling high-isolation MIMO mobile phone antenna to solve the problems of complex decoupling methods of existing antennas and insufficient isolation degree between antennas.

[0005] In view of this, the present invention provides a self-decoupling high-isolation MIMO mobile phone antenna, which includes a substrate, antenna elements, a feeding unit, a coaxial feeder, and a ground plane;

[0006] The substrate is composed of a bottom horizontal substrate and two side vertical substrates;

[0007] The antenna element is composed of a convex-shaped metal patch and is located outside the side substrate;

[0008] The feeding unit is composed of a T-shaped metal patch on the side substrate and a seventh rectangular metal patch on the bottom horizontal substrate. The T-shaped metal patch is located inside the side substrate;

[0009] The coaxial feeder is connected to the bottom horizontal substrate;

[0010] The ground plane is printed on the back of the bottom horizontal substrate;

[0011] The convex-shaped metal patch is symmetrically formed by sequentially connecting a first rectangle, a second rectangle, a third rectangle, and a fourth rectangle;

[0012] The T-shaped metal patch is formed by connecting a fifth rectangle and a sixth rectangle;

[0013] Optionally, for a self-isolated high-isolation MIMO mobile phone antenna, the size of the bottom horizontal substrate is 150 mm × 75 mm × 0.8 mm, the material is FR4, and the size of the side vertical substrate is 134 mm × 6 mm × 0.8 mm, the material is FR4.

[0014] Furthermore, for a self-isolated high-isolation MIMO mobile phone antenna, the number of antenna units is 6.

[0015] Optionally, for a self-isolated high-isolation MIMO mobile phone antenna, the number of feeding units is 6.

[0016] Furthermore, for a self-isolated high-isolation MIMO mobile phone antenna, the length of the first rectangle is 2.3 mm, the length of the second rectangle is 7.5 mm, the length of the third rectangle is 4.5 mm, the length of the fourth rectangle is 5.5 mm, and the widths of the first rectangle, the second rectangle, the third rectangle, and the fourth rectangle are all 0.6 mm.

[0017] Optionally, for a self-isolated high-isolation MIMO mobile phone antenna, the length of the fifth rectangle is 6 mm, the length of the sixth rectangle is 2.1 mm, and the widths of the fifth rectangle and the sixth rectangle are both 0.6 mm.

[0018] Furthermore, for a self-isolated high-isolation MIMO mobile phone antenna, the length of the seventh rectangle metal patch on the bottom horizontal substrate is 7.6 mm, and the width is 1 mm.

[0019] Optionally, for a self-isolated high-isolation MIMO mobile phone antenna, the T-shaped metal patch on the side small substrate and the rectangular metal patch on the bottom substrate are welded together to form a feeding unit.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The bandwidth of the present invention completely covers 3.3 GHz - 3.6 GHz and is applicable to 5G mobile phone systems;

[0022] (2) The isolation degree between the antenna units of the present invention is greater than -20 dB, and it has a good isolation effect;

[0023] (3) The antenna efficiency of the present invention is above 70%, achieving a very good utilization rate;

[0024] (4) The structure of the present invention is novel and simple, with low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of the self - decoupling high - isolation MIMO mobile phone antenna of the present invention;

[0026] Figure 2 is a structural diagram of the antenna unit on the vertical substrate 2 of the present invention;

[0027] Figure 3 is a structural diagram of the upper surface of the vertical substrate of the present invention;

[0028] Figure 4(a) is a simulation diagram of the S11 parameter of the present invention;

[0029] Figure 4(b) is a measured diagram of the S11 parameter of the present invention;

[0030] Figure 5(a) is a simulation diagram of the isolation degree of the antenna unit of the present invention.

[0031] Figure 5(b) is a measured diagram of the isolation degree of the antenna unit of the present invention.

[0032] Figure 6(a) is a comparison diagram of the simulated and measured radiation patterns of the antenna Ant1 of the present invention.

[0033] Figure 6(b) is a comparison diagram of the simulated and measured radiation patterns of the antenna Ant2 of the present invention.

[0034] Figure 6(c) is a comparison diagram of the simulated and measured radiation patterns of the antenna Ant3 of the present invention.

[0035] Figure 7 is a radiation efficiency diagram of the antennas Ant1, Ant2, and Ant3 simulated by the present invention.

[0036] Figure 8 is a correlation coefficient diagram between antenna units of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present invention will be further described below with reference to the drawings, so that the advantages and characteristics of the present invention can be more easily understood by those skilled in the art.

[0038] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a self - decoupling high - isolation MIMO mobile phone antenna provided by an embodiment of the present invention.

[0039] The present invention designs a self-decoupling high-isolation MIMO mobile phone antenna, which includes a horizontal substrate 1, a vertical substrate 2, a vertical substrate 3, an antenna unit 4, a feeding unit 5, and a ground plane 6.

[0040] The vertical substrate 2 and the vertical substrate 3 are respectively placed on both sides of the horizontal substrate. The antenna unit 4 is printed on the outer sides of the vertical substrate 2 and the vertical substrate 3. The ground plane is arranged on the bottom surface of the horizontal substrate 1. The feeding unit is composed of a T-shaped metal patch on the side substrate and a rectangular metal patch on the bottom horizontal substrate. The T-shaped metal patch is located inside the vertical substrate. The rectangular metal patch on the bottom horizontal substrate is connected to the T-shaped metal patch at the connection of the horizontal substrate and the vertical substrate. The coaxial feeder is arranged at the end of the rectangle of the feeding unit.

[0041] The horizontal substrate 1 is the mobile phone system substrate. In addition to carrying the feeding unit above, there are other electronic devices and batteries. The ground plane 6 is the mobile phone system ground plane, which is the ground connection surface for other electronic devices except the antenna. The feeding unit 5 is used to feed the antenna unit, and the antenna unit feeds and works through the coaxial feeder.

[0042] It can be understood that one antenna unit 4, one feeding unit 5 plus the ground plane 6 can form an antenna system. The antenna unit can independently complete signal receiving and transmitting work. The ground plane 6 and the horizontal substrate 1 are the common structures for all antenna units.

[0043] Please refer to Figure 2 , Figure 2 which is the structural diagram of the antenna unit on the vertical substrate 2.

[0044] As can be seen from Figure 2 , the antenna unit is composed of a metal patch in the shape of a convex character. The convex-shaped metal patch is symmetrically formed by sequentially connecting the first rectangle 7, the second rectangle 8, the third rectangle 9, and the fourth rectangle 10. The length of the first rectangle 7 is 2.3 mm, the length of the second rectangle 8 is 7.5 mm, the length of the third rectangle 9 is 4.5 mm, the length of the fourth rectangle 10 is 5.5 mm, and the widths of the first rectangle 7, the second rectangle 8, the third rectangle 9, and the fourth rectangle 10 are all 0.6 mm.

[0045] Please refer to Figure 3 , Figure 3 which is the upper surface of the vertical substrate.

[0046] As can be seen from Figure 2 , 3It can be known that the feeding unit is composed of a T-shaped structure on the inner side of the vertical substrate 2 and a seventh rectangle on the upper surface of the horizontal substrate. The T-shaped structure is composed of the fifth rectangle 11 and the sixth rectangle 12. The fifth rectangle 11 has a length of 6 mm, the sixth rectangle 12 has a length of 2.1 mm, and the fifth rectangle 11 and the sixth rectangle 12 both have a width of 0.6 mm. The seventh rectangle 13 has a length of 7.6 mm and a width of 1 mm.

[0047] The specific implementation is as follows:

[0048] The present invention adopts the circuit board etching technology to etch the structure of the antenna unit 4 on one side of the vertical substrate 2 and the vertical substrate 3, etch the T-shaped structure of the feeding unit on the other side, and etch the seventh rectangular structure on the upper surface of the horizontal substrate. The size of the horizontal substrate is 150 mm × 75 mm × 0.8 mm, and the material is FR4. The size of the side vertical substrate is 134 mm × 6 mm × 0.8 mm, and the material is FR4.

[0049] The electromagnetic simulation software ANSYS Electronics Desktop 2018.2 is used to simulate the MIMO system. After the simulation and debugging are completed, physical production and testing are carried out. The results of the S parameters are shown in Figure 4(a) and Figure 4(b). It can be seen from them that both the simulation and test results can cover 3.3 GHz - 3.6 GHz. Since the designed antenna array is mirror symmetric, all the measured units can cover 3.3 GHz - 3.6 GHz, meeting the requirements of 5G mobile communication.

[0050] As shown in Figure 5(a) and (c), the isolation degrees between the antenna units obtained by simulation and measurement are both above -20 dB, indicating that the coupling degree between the antenna units is very small.

[0051] As shown in Figure 6)(a), (b), and (c), they are the comparison diagrams of the simulated and measured two-dimensional radiation patterns of Ant1, Ant2, and Ant3 at the resonance point of 3.45 GHz in the XOZ plane and the YOZ plane. It can be seen from the figure that omnidirectional radiation is basically achieved. The reasons for the differences between the measurement and the simulation may be the errors in physical production and the problems in manual measurement operations.

[0052] Appendix Figure 7 It is the comparison diagram of the radiation efficiency of Ant1, Ant2, and Ant3 simulations. As shown in the figure, the measured antenna efficiency is above 65% in the 3.3 GHz - 5.1 GHz (5G) frequency band.

[0053] Appendix Figure 8It is the envelope correlation coefficient curve graph of the antenna element obtained by simulation. It can be seen from the figure that within the target frequency band, the maximum value of the ECC between antenna elements is lower than 0.01, meeting the operation standard of 5G MIMO (ECC < 0.5), and showing excellent spatial diversity characteristics.

[0054] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be construed as limiting the claimed invention.

[0055] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A self - decoupling high - isolation MIMO mobile phone antenna, characterized in that: It includes a substrate, an antenna unit, a feeding unit, a coaxial feeder, and a ground plane; The substrate is composed of a bottom horizontal substrate and two side vertical substrates; The antenna unit is composed of a convex-shaped metal patch and is located outside the side vertical substrate; The feeding unit is composed of a T-shaped metal patch on the side vertical substrate and a rectangular metal patch on the bottom horizontal substrate. The T-shaped metal patch is located inside the side vertical substrate; The coaxial feeder is connected to the bottom horizontal substrate; The ground plane is printed on the back of the bottom horizontal substrate; The convex-shaped metal patch is symmetrically composed of a first rectangle, a second rectangle, a third rectangle, and a fourth rectangle connected in sequence; The T-shaped metal patch is composed of a fifth rectangle and a sixth rectangle connected; The first rectangle has a length of 2.3 mm, the second rectangle has a length of 7.5 mm, the third rectangle has a length of 4.5 mm, the fourth rectangle has a length of 5.5 mm, and the first rectangle, the second rectangle, the third rectangle, and the fourth rectangle all have a width of 0.6 mm; The size of the bottom horizontal substrate is 150 mm × 75 mm × 0.8 mm, and the size of the side vertical substrate is 134 mm × 6 mm × 0.8 mm.

2. The self-decoupling high isolation MIMO mobile phone antenna according to claim 1, wherein The material of the bottom horizontal substrate is FR4, and the material of the side vertical substrate is FR4.

3. The self - decoupling high - isolation MIMO mobile phone antenna according to claim 1, characterized in that, There are 6 antenna units.

4. A self - decoupling high - isolation MIMO mobile phone antenna according to claim 1, characterized in that, There are 6 feeding units.

5. The self-decoupling high isolation MIMO mobile phone antenna according to claim 1, characterized in that, The fifth rectangle has a length of 6 mm, the sixth rectangle has a length of 2.1 mm, and the fifth rectangle and the sixth rectangle both have a width of 0.6 mm.

6. The self-decoupling high isolation MIMO mobile phone antenna according to claim 1, characterized in that The seventh rectangular metal patch on the bottom horizontal substrate has a length of 7.6 mm and a width of 1 mm.

7. The self-decoupling high isolation MIMO mobile phone antenna according to claim 1, characterized in that The T-shaped metal patch on the side vertical substrate and the rectangular metal patch on the bottom horizontal substrate are welded together to form a feeding unit.

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