A dual-band MIMO antenna assembly and a mobile terminal

Abstract

The present invention provides a dual-band MIMO antenna assembly and a mobile terminal, including a rectangular ground plane and a dielectric frame disposed around the edge of the ground plane; MIMO antenna units are disposed on the outer sides of both ends of each of the four sides of the dielectric frame, and the MIMO antenna units on both sides of each of the four corners of the dielectric frame are symmetrically distributed along the intersection line of the two sides forming the corner. Through the symmetric arrangement of the 8 MIMO antenna units at the four corners of the dielectric frame, the dual-band MIMO antenna assembly not only has good radiation performance but also has high isolation in the Sub-6G frequency band range, solving the problem of how to make the Sub-6G antenna perform dual-band radiation and ensure its isolation.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and particularly relates to a dual-band MIMO antenna assembly and a mobile terminal. Background Art

[0002] At present, in order to improve the wireless communication level of mobile terminals, antennas are usually designed in the MIMO form. MIMO means that two or more co-frequency antennas work simultaneously. Generally speaking, multiple co-frequency antennas of a MIMO antenna have the same antenna structure, and the co-frequency efficiency generated in this way has a multiplying effect, thereby improving the transceiver performance of the antenna.

[0003] Currently, with the development of 5G communication technologies, the research focuses on Sub-6GHz antennas. 3GPP has defined two FR (frequency ranges) for 5G NR use. Among them, FR1 includes some frequency bands used by 2 / 3 / 4G, and some new frequency bands are also added. The defined frequency range of the new frequency bands is 450 - 6000 MHz. Since the wireless spectrum is all below 6G, the new frequency bands are usually referred to as Sub-6G.

[0004] At present, Sub-6GHz antennas are usually designed in the form of MIMO antennas to ensure better efficiency in the radiation performance of the same frequency, so as to effectively ensure the radiation intensity of Sub-6GHz antennas. However, there are still two difficulties in the current design of Sub-6GHz MIMO antennas:

[0005] First, whether the Sub-6GHz MIMO antenna can cover all frequency bands of N77 (3300 - 4200 MHz), N78 (3300 - 3800 MHz), and N79 (4400 - 5000 MHz); existing Sub-6GHz MIMO antennas usually only have one frequency band, and there are very few antenna solutions for covering dual-frequency or multi-frequency bands.

[0006] Second, how to ensure the isolation degree between MIMO antennas, especially for wide-band Sub-6GHz antennas, it is a relatively difficult problem to ensure good isolation within the wide frequency band; since the MIMO antenna itself has multiple antenna elements, how to ensure the isolation degree between multiple antenna elements and how to ensure the isolation degree between the MIMO antenna and other antennas in the terminal are problems that must be solved. If the isolation degree is not good, it will seriously affect the communication quality of the antenna. Summary of the Invention

[0007] The purpose of the present invention is to provide a dual-band MIMO antenna assembly and a mobile terminal to solve the problem of how to make a Sub-6G antenna perform dual-band radiation and ensure its isolation degree.

[0008] To solve the above technical problems, the present invention provides a dual-band MIMO antenna assembly, which includes a rectangular ground plane and a dielectric frame disposed around the edge of the ground plane; on each of the four sides of the dielectric frame, MIMO antenna units are provided on the outer sides of both ends thereof, and the MIMO antenna units on both sides of each of the four corners of the dielectric frame are symmetrically distributed along the intersection line of the two sides forming the corner.

[0009] Optionally, in the dual-band MIMO antenna assembly, the dielectric frame has a dielectric constant of 2.2 and a thickness of 1.52 ± 0.1 mm.

[0010] Optionally, in the dual-band MIMO antenna assembly, the dual-band MIMO antenna assembly further includes a housing, and the housing is located outside the dielectric frame so that the MIMO antenna units are located between the dielectric frame and the housing.

[0011] Optionally, in the dual-band MIMO antenna assembly, the MIMO antenna unit includes a rectangular ring-shaped high-frequency loop stub and a cross-shaped low-frequency stub, and one end of the low-frequency stub is connected to a corner of the high-frequency loop stub.

[0012] Optionally, in the dual-band MIMO antenna assembly, the low-frequency stub includes a first low-frequency branch and a second low-frequency branch that are perpendicularly arranged; one end of the first low-frequency branch is connected to a corner of the high-frequency loop stub and is in a straight line with the short side of the high-frequency loop stub; the second low-frequency branch is parallel to the long side of the high-frequency loop stub.

[0013] Optionally, in the dual-band MIMO antenna assembly, a feeding point is provided at the end of the first low-frequency branch away from the high-frequency loop stub.

[0014] Optionally, in the dual-band MIMO antenna assembly, the MIMO antenna unit further includes a linear parasitic stub, and one end of the parasitic stub is connected to another corner of the high-frequency loop stub.

[0015] Optionally, in the dual-band MIMO antenna assembly, the parasitic stub is in a straight line with the long side at the connected corner.

[0016] Optionally, in the dual-band MIMO antenna assembly, the connection points of the parasitic stub and the low-frequency stub with the high-frequency loop stub are respectively located at both ends of the same short side of the high-frequency loop stub.

[0017] To solve the above technical problems, the present invention further provides a mobile terminal, which includes the dual-band MIMO antenna assembly as described in any one of the above.

[0018] The dual - band MIMO antenna assembly and mobile terminal provided by the present invention include a rectangular floor and a dielectric frame disposed around the edge of the floor; MIMO antenna units are provided on the outer sides of both ends of each of the four sides of the dielectric frame, and the MIMO antenna units on both sides of each of the four corners of the dielectric frame are symmetrically distributed along the intersection line of the two sides forming the corner. Through the symmetrical arrangement of the 8 MIMO antenna units at the four corners of the dielectric frame, the dual - band MIMO antenna assembly not only has good radiation performance but also has high isolation in the Sub - 6G frequency band range, solving the problem of how to make the Sub - 6G antenna perform dual - band radiation and ensure its isolation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a schematic structural diagram of the dual - band MIMO antenna assembly provided in this embodiment;

[0020] Figure 2 FIG. is a schematic structural diagram of the MIMO antenna unit in the dual - band MIMO antenna assembly provided in this embodiment;

[0021] Figure 3 FIG. is a schematic dimension diagram of the MIMO antenna unit in the dual - band MIMO antenna assembly provided in this embodiment;

[0022] Figure 4 FIG. is a simulation result diagram of the S - parameter of the dual - band MIMO antenna assembly provided in this embodiment;

[0023] Figure 5 FIG. is a simulation result diagram of the isolation of the dual - band MIMO antenna assembly provided in this embodiment;

[0024] Among them, the descriptions of the reference numerals are as follows:

[0025] 100 - floor; 200 - dielectric frame; 300 - MIMO antenna unit; 310 - high - frequency loop stub; 320 - low - frequency stub; 321 - feeding point; 330 - parasitic stub. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following further describes the dual - band MIMO antenna assembly and mobile terminal proposed by the present invention in detail with reference to the drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use non - precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structures. In particular, the emphasis points to be shown in each drawing are different, and sometimes different scales are used.

[0027] It should be noted that the "first", "second", etc. in the description, claims and drawings of the present invention are used to distinguish similar objects for describing embodiments of the present invention, rather than for describing a specific order or sequence. It should be understood that the structures used in this way can be interchanged under appropriate circumstances. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0028] This embodiment provides a dual-band MIMO antenna assembly, as Figure 1 shown, including a rectangular floor 100 and a dielectric frame 200 disposed around the edge of the floor 100; MIMO antenna units 300 are disposed on the outer side of each end of each of the four sides of the dielectric frame 200, and the MIMO antenna units 300 on both sides of each of the four corners of the dielectric frame 200 are symmetrically distributed along the intersection line of the two sides forming the corner.

[0029] In the dual-band MIMO antenna assembly provided in this embodiment, through the symmetrical arrangement of the 8 MIMO antenna units at the four corners of the dielectric frame, the dual-band MIMO antenna assembly not only has good radiation performance but also has high isolation in the Sub-6G frequency band range, solving the problem of how to make the Sub-6G antenna perform dual-band radiation and ensure its isolation.

[0030] Specifically, in this embodiment, the material of the floor 100 can be metal, serving as the metal floor of the antenna. The dielectric constant of the dielectric frame 200 is 2.2, and the thickness is 1.52 ± 0.1 mm.

[0031] In the specific application process, usually a mobile terminal is also provided with a housing to wrap the internal structure of the mobile terminal. In this embodiment, the dual-band MIMO antenna assembly further includes a housing, and the housing is located outside the dielectric frame 200 so that the MIMO antenna units 300 are located between the dielectric frame 200 and the housing.

[0032] Preferably, the material of the housing is a plastic material such as ABS to avoid interference and occlusion with the radiation of the antenna.

[0033] To enable the MIMO antenna element pairs at the four corners of the dielectric frame 200 to achieve the same radiation performance, so as to optimize the overall radiation performance of the dual-band MIMO antenna assembly. In this embodiment, the relative positions, sizes, directions, etc. of the four pairs of MIMO antenna elements 300 at the corners are the same. Specifically, it can be formed by laser using the LDS process on the outer side of the dielectric frame 200.

[0034] Further, in this embodiment, as Figure 2 shown, the MIMO antenna element 300 includes a high-frequency loop branch 310 in a rectangular ring shape and a low-frequency branch 320 in a cross shape. One end of the low-frequency branch 320 is connected to a corner of the high-frequency loop branch 310.

[0035] Preferably, the low-frequency branch 320 includes a first low-frequency branch and a second low-frequency branch arranged perpendicular to each other; one end of the first low-frequency branch is connected to a corner of the high-frequency loop branch 310 and is in a straight line with the short side of the high-frequency loop branch 310; the second low-frequency branch is parallel to the long side of the high-frequency loop branch 310. Specifically, a feeding point 321 is provided at the end of the first low-frequency branch far from the high-frequency loop branch.

[0036] In this way, when feeding, resonance of the low-frequency (3.7 GHz) part can be formed on the second low-frequency branch, and resonance of the high-frequency (4.9 GHz) part can be formed on the high-frequency loop branch 310, so that dual-band radiation of the MIMO antenna can be formed.

[0037] Preferably, to improve the resonance effect of the high-frequency part, in this embodiment, the MIMO antenna element further includes a parasitic branch 330 in a straight shape. One end of the parasitic branch 330 is connected to another corner of the high-frequency loop branch 320.

[0038] Further, in this embodiment, the parasitic branch 330 is in a straight line with the long side at the connected corner.

[0039] Furthermore, in this embodiment, the connections of the parasitic branch 330 and the low-frequency branch 310 to the high-frequency loop branch 320 are respectively located at both ends of the same short side of the high-frequency loop branch 320.

[0040] In this way, good parasitic resonance can occur between the parasitic branch 330 and both the low-frequency branch 310 and the high-frequency loop branch 320, thereby improving the resonance performance of the dual-band MIMO antenna assembly at low and high frequencies.

[0041] In the design of a specific MIMO antenna unit, the high-frequency loop stub 320 of the MIMO antenna units 300 on both sides of the same corner of the dielectric frame 200 is arranged oppositely, so that the parasitic stub 330 serves as the radiation end of high frequency to transmit and receive signals outward, thereby improving the isolation degree between MIMO antenna units.

[0042] In practical applications, the MIMO antenna units 300 can be formed on the outer side of the dielectric frame 200 by using printing technology or LDS technology, which can not only ensure the high consistency of the positions of the MIMO antenna units 300 with each other, but also improve the manufacturing efficiency and adapt to the realization of the MIMO antenna unit structure with complex structure.

[0043] When using printing technology, if ordinary conductive silver paste is adopted, a spraying process can be added after the printing process to ensure the color consistency of the dielectric frame; preferably, transparent conductive silver paste can be used to make the MIMO antenna units "invisible", which not only saves the spraying process, but also ensures the beauty of the dielectric frame.

[0044] Of course, the insert injection molding process can also be used to integrally form the metal MIMO antenna unit and the dielectric frame through the injection molding process to ensure the stability of the combination of the MIMO antenna unit and the dielectric frame.

[0045] If the MIMO antenna unit structure with an ordinary FPC structure is adopted, usually a frame needs to be formed outside the dielectric frame, and the dielectric frame is wrapped by the frame so that the MIMO antenna unit is fixed outside the dielectric frame.

[0046] It should be noted that the selection of materials, dimensions, relative positions, etc. of the components of the dual-band MIMO antenna assembly proposed by the present invention are a preferred solution, and the selection of other materials, dimensions, and relative position settings without violating the main idea of the present invention should also fall within the protection scope of the present invention.

[0047] In the specific application process, the bottom (the end where the feeding point is set) of the MIMO antenna unit 300 is arranged close to the main board of the mobile terminal, which is beneficial to the connection between the feeding point and the feeding elastic sheet on the main board, and is also beneficial to the wireless signal transmission and reception at the end far from the feeding point, improving its radiation performance. Specifically, when there is only one feeding elastic sheet on the main board and the feeding elastic sheet is far away from the feeding points of each MIMO antenna unit, the feeding points of each MIMO antenna unit can be welded to the feeding elastic sheet through coaxial cables to realize the electrical connection between the feeding point and the feeding elastic sheet; when there are feeding elastic sheets arranged at the corresponding positions of each MIMO antenna unit on the main board, the feeding point and the feeding elastic sheet can be directly connected by using a small section of antenna stub.

[0048] Of course, the feeding elastic sheet can also be connected with a radio frequency matching circuit. As is well known to those skilled in the art, when there is only one feeding elastic sheet, only one radio frequency matching circuit needs to be designed; when there are multiple feeding elastic sheets, in order to ensure that the radiation performance of each MIMO antenna unit is the same, the radio frequency matching circuits connected to each feeding elastic sheet should also be the same, and each radio frequency matching circuit should be connected to the same control chip. Preferably, multiple leads can be drawn from the same position of a radio frequency matching circuit, and the terminal of each lead is a feeding elastic sheet, so as to implement a scheme where one radio frequency matching circuit corresponds to multiple feeding elastic sheets.

[0049] As those skilled in the art can know, the radio frequency matching circuit has various forms and can be designed according to actual needs, which will not be elaborated here.

[0050] It should be noted that as is well known to those skilled in the art, the same antenna routing form has different radiation performances in different terminals. When applied to a specific terminal structure, it needs to be tuned according to the specific antenna environment. Other antenna routing forms (such as adding some branches) and changing the number of MIMO antenna units (such as changing the 8 MIMO antenna units to 16 MIMO antenna units, that is, adding a pair of MIMO antenna units at each corner) without violating the gist of the present invention are all within the protection scope of the present invention.

[0051] The following will make a specific description of the dual - band MIMO antenna assembly provided by the present invention with reference to Figures 1 to 3 as shown below.

[0052] In this embodiment, MIMO antenna units 300 are symmetrically arranged at the four corners of the dielectric frame 200. Each MIMO antenna unit 300 includes a high - frequency loop branch 310 in a rectangular ring shape, a low - frequency branch 320 in a cross shape, and a parasitic branch 330 in a straight shape. The long side of the high - frequency loop branch 310 is placed horizontally, and the short side is placed vertically; a feeding point 321 is arranged at the low - frequency branch 320 near the floor 100. Taking the floor 100 as a reference, the highest end of the low - frequency branch 320 is connected to a corner of the high - frequency loop branch 310, and the vertically placed part of the low - frequency branch 320 is in a straight line with the short side of the high - frequency loop branch 310, and the horizontally placed part is parallel to the long side of the high - frequency loop branch 310; the parasitic branch 330 is connected to the other corner of the high - frequency loop branch 310 and is in a straight line with the long side of the high - frequency loop branch 310. The direction of the parasitic branch 330 is the same as that of the low - frequency branch 320, and they are both located on one side of the same short side of the high - frequency loop branch 310, that is, connected to the two ends of the same short side of the high - frequency loop branch 310.

[0053] For the MIMO antenna units 300 on both sides of the same corner, their high - frequency loop branches 310 are arranged oppositely, that is, the parasitic branches 330 are arranged on the side away from the corner intersection line.

[0054] In this embodiment, the size of the floor 100 is 150×80 mm, which is the standard size of a conventional mobile phone. The dielectric frame 200 is a PCB board with a dielectric constant of 2.2 and a thickness of 1.52 mm. In the MIMO antenna unit 300, the length of the horizontally placed part of the low-frequency stub 320 is 13 mm, the trace width is 0.5 mm, and it extends 4.2 mm along the side away from the high-frequency loop stub 310. The trace width of the vertically placed part is the same as that of the short side connected to the high-frequency loop stub 310, which is 1.1 mm. The height of the horizontal part relative to the vertical part needs to be fine-tuned according to the actual environment where the antenna is located. By controlling the distance between the horizontal part of the low-frequency stub 320 and the high-frequency loop stub 310 and the distance from the feeding point 321, a good resonance of the low-frequency part generated thereon can be achieved. The long side length of the high-frequency loop stub 310 is 11 mm, and the short side length is 3.3 mm; the trace width of the long side on the side close to the low-frequency stub 320 is 1.2 mm, the trace width of the long side on the side away from the low-frequency stub 320 is 0.8 mm, and the width of the short side on the side away from the low-frequency stub 320 is 0.5 mm. Setting the trace widths of the long side and the short side near the low-frequency stub 320 to be wider can ensure less loss of current in this part and enhance the coupling with the low-frequency stub 320, thereby improving the radiation performance of the high-frequency part. The length of the parasitic stub 330 is 3.8 mm, and the trace width is the same as that of the adjacent long side, which is 0.8 mm.

[0055] The distance between the MIMO antenna units 300 on both sides of the same corner from the corner intersection line depends on the specific antenna environment, and generally this distance is between 0.3 and 2 mm.

[0056] It should be noted that the tolerance of the above specific dimensions is ±10% of their central dimensions (the dimensions given above), and two decimal places are reserved. For example, for a width of 0.8 mm, its tolerance is ±0.08 mm.

[0057] Using the above dual-band MIMO antenna assembly for simulation, the simulation results of its S parameters are as Figure 4 shown, and the simulation results of its isolation are as Figure 5 shown. It can be seen from Figure 4 that for the dual-band MIMO antenna assembly provided in this embodiment, S11 < -10 dB in the ranges of 3.4 - 3.6 GHz and 4.8 - 5.0 GHz, and the antenna efficiency > 60%. This indicates that the dual-band MIMO antenna assembly provided in this embodiment achieves good radiation at the corresponding Sub-6G frequency points. From Figure 5It can be seen that the isolation between the MIMO antenna units 300 on both sides of the same corner reaches 20 dB. At the same time, the isolation between the MIMO antenna units 300 at both ends of the same side also reaches 20 dB. In this way, the overall isolation between the 8 MIMO antenna units is relatively high.

[0058] This embodiment also provides a mobile terminal, including the dual-band MIMO antenna assembly provided in this embodiment. The mobile terminal includes, but is not limited to, mobile phones, laptops, tablet computers, etc.

[0059] Specifically, when the mobile terminal is a mobile phone or a tablet computer, considering that the internal space of the mobile phone is small and the appearance requirements are as thin and light as possible, the thickness of its frame is generally not too thick. Therefore, the MIMO antenna units can be formed on the dielectric frame by printing technology or LDS technology, and only a pair of MIMO antenna units are arranged at each corner. At the same time, a radio frequency matching circuit is arranged on the main board, so as to optimize the performance of the MIMO antenna assembly. When the mobile terminal is a laptop or other devices with a thicker frame, the number of MIMO antenna pairs can be increased to further improve the radiation performance of the MIMO antenna assembly. When connecting the MIMO antenna unit to the main board, a coaxial cable can also be selected to connect the feeding point and the feeding elastic sheet.

[0060] On some other mobile terminals, the setting of the MIMO antenna assembly can be realized by referring to the above setting method. Of course, on a mobile terminal, in addition to the dual-band MIMO antenna assembly provided in this embodiment, there are also many other antennas. It is necessary to comprehensively consider the interaction between the antennas to ensure that, without affecting the normal operation of each antenna, the occupation of the antenna space is reduced as much as possible, so as to realize the rationality of the antenna layout.

[0061] In summary, the dual-band MIMO antenna assembly and mobile terminal provided in this embodiment include a rectangular ground plane and a dielectric frame arranged around the edge of the ground plane; MIMO antenna units are arranged on the outer sides of both ends of each of the four sides of the dielectric frame, and the MIMO antenna units on both sides of each of the four corners of the dielectric frame are symmetrically distributed along the intersection line of the two sides forming the corner. Through the symmetric setting of the 8 MIMO antenna units at the four corners of the dielectric frame, the dual-band MIMO antenna assembly not only has good radiation performance in the Sub-6G frequency band range, but also has a high isolation degree, solving the problem of how to make the Sub-6G antenna perform dual-band radiation and ensure its isolation degree.

[0062] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A dual-band MIMO antenna assembly, characterized in that, It includes a rectangular floor and a dielectric border arranged around the edge of the floor; on each of the four sides of the dielectric border, MIMO antenna units are arranged outside both ends of each side, and the MIMO antenna units on both sides of each of the four corners of the dielectric border are axially symmetrically distributed along the intersection line of the two sides forming the corner; the MIMO antenna unit includes a rectangular-ring-shaped high-frequency loop stub and a cross-shaped low-frequency stub, and one end of the low-frequency stub is connected to a corner of the high-frequency loop stub; the low-frequency stub includes a first low-frequency branch and a second low-frequency branch arranged perpendicular to each other; one end of the first low-frequency branch is connected to a corner of the high-frequency loop stub and is in a straight line with the short side of the high-frequency loop stub; the second low-frequency branch is parallel to the long side of the high-frequency loop stub.

2. The dual-band MIMO antenna assembly according to claim 1, characterized in that, The dielectric constant of the dielectric border is 2.2, and the thickness is 1.52 ± 0.1 mm.

3. The dual-band MIMO antenna assembly according to claim 1, characterized in that, The dual-band MIMO antenna assembly further includes a housing, and the housing is located outside the dielectric border so that the MIMO antenna unit is located between the dielectric border and the housing.

4. The dual-band MIMO antenna assembly according to claim 1, characterized in that, A feeding point is arranged at the end of the first low-frequency branch far from the high-frequency loop stub.

5. The dual-band MIMO antenna assembly according to claim 1, characterized in that, The MIMO antenna unit further includes a linear parasitic stub, and one end of the parasitic stub is connected to another corner of the high-frequency loop stub.

6. The dual-band MIMO antenna assembly according to claim 5, characterized in that, The parasitic stub is in a straight line with the long side at the connected corner.

7. The dual-band MIMO antenna assembly according to claim 5, characterized in that, The connection points of the parasitic stub and the low-frequency stub with the high-frequency loop stub are respectively located at both ends of the same short side of the high-frequency loop stub.

8. A mobile terminal, characterized in that, It includes the dual-band MIMO antenna assembly according to any one of claims 1 to 7.

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