A miniaturized dual-band wideband MIMO antenna based on pattern cancellation method

Abstract

The application belongs to the technical field of antennas, and particularly relates to a miniaturized dual-frequency wideband MIMO antenna based on a mode cancellation method, which comprises a horizontal dielectric substrate and a vertical dielectric substrate, the vertical dielectric substrate is connected to one side of the long side of the horizontal dielectric substrate, a grounding structure is printed on the bottom of the horizontal dielectric substrate, and an antenna is printed on the vertical dielectric substrate; the antenna comprises two symmetrically arranged antenna units, the antenna units are printed on the vertical dielectric substrate, the antenna units are connected with a microstrip feed structure, the microstrip feed structure is arranged on the horizontal dielectric substrate, a decoupling structure is arranged between the two antenna units, a gap is arranged between the antenna units and the decoupling structure, and the antenna units and the decoupling structure are both arranged in a grounded mode. By adopting the mode cancellation technology, the application realizes high isolation characteristics in two working frequency bands, reduces the overall size of the antenna, and simplifies the antenna structure.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and particularly relates to a miniaturized dual-band broadband MIMO antenna based on the mode cancellation method. Background Technology

[0002] Multiple-input multiple-output (MIMO) technology, by configuring multiple antennas, can significantly improve the system's spectrum efficiency and channel capacity without occupying additional spectrum resources or increasing transmit power, thus becoming a core supporting technology for modern communication systems.

[0003] As the core of a MIMO system, the performance of the antenna directly affects the communication quality of the entire wireless communication system. However, in practical MIMO antenna design, the mutual coupling effect between elements remains a bottleneck restricting the improvement of system performance. This mutual coupling effect can cause antenna input impedance mismatch, leading to increased reflection loss and decreased radiation efficiency; it can also cause radiation pattern distortion, causing the radiation direction to deviate from the preset trajectory, adversely affecting coverage and transmission quality. In addition, mutual coupling can enhance the correlation between MIMO channels, weaken spatial multiplexing and spatial diversity gain, and thus reduce system capacity and reliability.

[0004] Currently, decoupling techniques can be categorized into three types: first, cancellation techniques, which introduce new coupling paths to cancel out existing coupling; second, blocking techniques, which utilize band-stop structures such as defective ground structures (DGS) and electromagnetic bandgap structures (EBG) to block the propagation path of electromagnetic waves in specific frequency bands between elements; and third, self-decoupling techniques, which leverage the decoupling characteristics within the antenna modes to achieve decoupling without the need for additional decoupling structures. Mode cancellation, as a relatively novel decoupling method, primarily places its decoupling structure between the antenna and different ports, requiring no additional space and thus facilitating antenna miniaturization. Summary of the Invention

[0005] The purpose of this invention is to provide a miniaturized dual-band broadband MIMO antenna based on the mode cancellation method to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A miniaturized dual-band broadband MIMO antenna based on mode cancellation method, comprising:

[0008] A horizontal dielectric substrate and a vertical dielectric substrate, wherein the vertical dielectric substrate is connected to one side of the long side of the horizontal dielectric substrate;

[0009] A grounding structure is printed on the bottom of the horizontal dielectric substrate;

[0010] The antenna is printed on the vertical dielectric substrate;

[0011] The antenna includes two symmetrically arranged antenna elements printed on the vertical dielectric substrate. The antenna elements are connected to a microstrip feed structure, which is disposed on the horizontal dielectric substrate. A decoupling structure is provided between the two antenna elements.

[0012] A gap is provided between the antenna element and the decoupling structure;

[0013] Both the antenna unit and the decoupling structure are grounded.

[0014] Optionally, the decoupling structure includes two decoupling metal strips printed between the two antenna elements. The two adjacent decoupling metal strips are parallel and spaced apart. The ends of the decoupling metal strips are spaced apart from the edges of the corresponding antenna elements. The decoupling metal strips are grounded.

[0015] Optionally, the antenna element has a U-shaped structure, wherein the antenna element has two horizontal segments of unequal length.

[0016] Optionally, the microstrip feeding structure includes a microstrip feed metal strip, which is printed on the horizontal dielectric substrate and connected to the corresponding antenna element.

[0017] Optionally, at least one vertical dielectric substrate is provided, and when there is more than one antenna, several antennas are printed on the vertical dielectric substrate, with adjacent antennas spaced apart.

[0018] Optionally, the grounding structure includes:

[0019] A metal floor is printed on the bottom of the horizontal dielectric substrate;

[0020] Both the antenna unit and the decoupling structure are connected to the metal ground plane.

[0021] A clearance area is provided between the edge of the metal floor and the vertical dielectric substrate.

[0022] Optionally, the length of the clearance area is equal to the length of the metal floor.

[0023] Optionally, both the horizontal dielectric substrate and the vertical dielectric substrate are made of glass fiber epoxy resin material.

[0024] Optionally, the thickness of the horizontal dielectric substrate is 2 mm.

[0025] Optionally, the thickness of the vertical dielectric substrate is 1 mm.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] This invention employs mode cancellation technology to introduce a specific decoupling structure between two antenna elements, achieving high isolation characteristics within two operating frequency bands without occupying additional space. This not only effectively reduces mutual interference between antennas but also significantly reduces the overall size of the antenna, simplifies the antenna structure, and successfully realizes the miniaturization design of the antenna system. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is one of the structural schematic diagrams of the present invention.

[0030] Figure 2 This is the second schematic diagram of the structure of the present invention.

[0031] Figure 3 This is the S-parameter diagram of the present invention.

[0032] Figure 4 This is a Smith chart comparing the common-mode reflection coefficient and differential-mode reflection coefficient in the 3.37-3.98GHz frequency band of this invention.

[0033] Figure 5 This is a Smith chart comparing the common-mode reflection coefficient and differential-mode reflection coefficient in the 4.19-7.29GHz frequency band of this invention.

[0034] The components are as follows: 1. Horizontal dielectric substrate; 2. Vertical dielectric substrate; 3. Clearance area; 4. Antenna; 5. Antenna element one; 51. First horizontal microstrip structure; 52. Second vertical microstrip structure; 53. Third horizontal microstrip structure; 6. Antenna element two; 7. Metal via one; 8. Metal via two; 9. Rectangular metal strip one; 10. Rectangular metal strip two; 11. Metal via three; 12. Metal via four; 13. Microstrip feed line one; 14. Microstrip feed line two; 15. Microstrip line one; 16. Metal via five; 17. Metal ground plane; 18. Microstrip line two; 19. Microstrip line three; 20. Microstrip line four; 21. Metal via six; 22. Metal via seven. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Reference Figures 1 to 5 This invention discloses a miniaturized dual-band broadband MIMO antenna based on a mode cancellation method, comprising:

[0038] A horizontal dielectric substrate 1 and a vertical dielectric substrate 2 are connected to one side of the long side of the horizontal dielectric substrate 1.

[0039] A grounding structure is printed on the bottom of the horizontal dielectric substrate 1;

[0040] Antenna 4 is printed on vertical dielectric substrate 2;

[0041] Antenna 4 includes two symmetrically arranged antenna elements. The antenna elements are printed on the vertical dielectric substrate 2. The antenna elements are connected to a microstrip feed structure. The microstrip feed structure is arranged on the horizontal dielectric substrate 1. A decoupling structure is provided between the two antenna elements.

[0042] A gap is provided between the antenna element and the decoupling structure;

[0043] Both the antenna unit and the decoupling structure are grounded.

[0044] This invention employs mode cancellation technology to introduce a specific decoupling structure between two antenna elements, achieving high isolation characteristics within two operating frequency bands without occupying additional space. This not only effectively reduces mutual interference between antennas but also significantly reduces the overall size of the antenna, successfully realizing the miniaturization design of the antenna system.

[0045] in, Figure 1 Arrow A represents the top view of the device, and arrow B represents the bottom view of the device.

[0046] As an optional implementation, the decoupling structure includes two decoupling metal strips printed between two antenna elements. The two adjacent decoupling metal strips are parallel and spaced apart. The ends of the decoupling metal strips are spaced apart from the edges of the corresponding antenna elements. The decoupling metal strips are grounded.

[0047] Two decoupling metal strips are provided, namely rectangular metal strip 19 and rectangular metal strip 210. Rectangular metal strip 19 and rectangular metal strip 210 are provided between two antenna elements. The ends of rectangular metal strip 19 and rectangular metal strip 210 are left with gaps to the edges of the corresponding antenna elements. Rectangular metal strip 19 and rectangular metal strip 210 are provided at intervals.

[0048] The rectangular metal strip 9 is grounded through the metal via 311;

[0049] The rectangular metal strip 210 is grounded through the metal via 412.

[0050] As an alternative implementation, the antenna element has a U-shaped structure, wherein the antenna element has two horizontal segments of unequal length.

[0051] Antenna 4 has two antenna elements, namely antenna element 5 and antenna element 6. Antenna element 5 and antenna element 6 are symmetrically arranged, and antenna element 5 and antenna element 6 have the same structure.

[0052] Antenna element 5 includes a first horizontal microstrip structure 51, a second vertical microstrip structure 52 and a third horizontal microstrip structure 53, which are integral structures. The length of the third horizontal microstrip structure 53 is greater than the length of the first horizontal microstrip structure 51. The first horizontal microstrip structure 51 of antenna element 5 is connected to the corresponding microstrip feed structure through a metal via 8. The first horizontal microstrip structure 51 of antenna element 6 is connected to the corresponding microstrip feed structure through a metal via 7.

[0053] The second vertical microstrip structure 52 of antenna element 1 5 is grounded through metal via 7 22, and the second vertical microstrip structure 52 of antenna element 2 6 is grounded through metal via 6 21.

[0054] As an optional implementation, the microstrip feed structure includes a microstrip feed metal strip disposed on a horizontal dielectric substrate 1, and the microstrip feed metal strip is connected to a corresponding antenna element.

[0055] Microstrip feed line 13 is connected to the first horizontal microstrip structure 51 of antenna element 5 through metal via 8. Microstrip feed line 13 serves as the microstrip feeding structure of antenna element 5.

[0056] Microstrip feed line 14 is connected to the first horizontal microstrip structure 51 of antenna element 6 through metal via 7. Microstrip feed line 14 serves as the microstrip feeding structure of antenna element 6.

[0057] As an optional implementation, at least one vertical dielectric substrate 2 is provided, and when there is more than one antenna 4, several antennas 4 are printed on the vertical dielectric substrate 2, with adjacent antennas 4 spaced apart.

[0058] As an optional implementation, the grounding structure includes:

[0059] Metal floor 17 is printed on the bottom of horizontal dielectric substrate 1;

[0060] The antenna unit and decoupling structure are both connected to the metal ground plane 17;

[0061] A clearance area 3 is provided between the edge of the metal floor 17 and the vertical dielectric substrate 2.

[0062] One end of the rectangular metal strip 9 is connected to one end of the microstrip line 15 through the metal via 11, and the other end of the microstrip line 15 is connected to the metal floor 17 through the metal via 16.

[0063] A rectangular metal strip 10 is connected to one end of a microstrip line 18 through a metal via 12, and the other end of the microstrip line 18 is connected to a metal ground plane 17.

[0064] The second vertical microstrip structure 52 of antenna element 26 is connected to one end of microstrip line 319 through metal via 621, and the other end of microstrip line 319 is connected to metal ground plane 17.

[0065] The second vertical microstrip structure 52 of antenna element 15 is connected to one end of microstrip line 4 20 through metal via 7 22, and the other end of microstrip line 4 20 is connected to metal ground plane 17.

[0066] As an alternative implementation, the length of the clearance area 3 is equal to the length of the metal floor 17.

[0067] As an optional implementation, both the horizontal dielectric substrate 1 and the vertical dielectric substrate 2 are made of glass fiber epoxy resin material.

[0068] As an optional implementation, the thickness of the horizontal dielectric substrate 1 is 2 mm.

[0069] As an optional implementation, the thickness of the vertical dielectric substrate 2 is 1 mm.

[0070] Based on the above technical features, the present invention is specifically described with a miniaturized dual-frequency broadband MIMO antenna having a mode cancellation method, which includes a horizontal dielectric substrate 1, a vertical dielectric substrate 2, an antenna 4, and a metal ground plane 17.

[0071] A vertical dielectric substrate 2 is placed on one side of the long side of a horizontal dielectric substrate 1, and an antenna 4 is printed on the middle of the outer side of the vertical dielectric substrate 2.

[0072] Antenna 4 consists of antenna element 5 and antenna element 6 with identical structures, and antenna element 5 and antenna element 6 are arranged symmetrically.

[0073] Among them, antenna element 5 is composed of a first horizontal microstrip structure 51, a second vertical microstrip structure 52 and a third horizontal microstrip structure 53 connected in sequence, and the length of the first horizontal microstrip structure 51 is less than the length of the third horizontal microstrip structure 53.

[0074] The second vertical microstrip structure 52 is connected to microstrip line 20 via metal via 7 22. Rectangular metal strip 1 9 and rectangular metal strip 2 10 are printed between antenna element 1 5 and antenna element 2 6. Rectangular metal strip 1 9 is connected to microstrip line 1 15 via metal via 3 11, and the end of microstrip line 1 15 is connected to metal ground plane 17 via metal via 5 16. Rectangular metal strip 2 10 is connected to microstrip line 2 18 via metal via 4 12, and microstrip line 2 18 is connected to metal ground plane 17.

[0075] A metal ground plane 17 is printed on the lower surface of the horizontal dielectric substrate 1, and a clearance area 3 of the same length as the metal ground plane 17 is left on one side of the long side. A microstrip feed line 13 is connected to the end of the first horizontal microstrip structure 51 through a metal via 8, and the antenna element is fed by a coaxial feed line.

[0076] By adjusting the parameters of the first horizontal microstrip structure 51 and the third horizontal microstrip structure 53, the antenna can operate in two frequency bands, namely 3.37-3.98GHz and 4.19-7.29GHz, and can be well applied to 5G and 6G communication systems.

[0077] Figure 3 The S-parameter plot of the antenna is shown. As can be seen from the plot, the antenna covers two frequency bands, and the reflection coefficient is less than -6dB throughout the entire operating frequency band, indicating that the antenna achieves good impedance matching in both frequency bands.

[0078] Meanwhile, according to the mode cancellation theory, when the common-mode reflection coefficient (Scc) of a symmetrical reciprocal two-port antenna system... 11 ) and differential mode reflection coefficient (Sdd) 11 The difference between them satisfies the formula |Scc 11 -Sdd 11 When the condition is less than 0.632, decoupling between ports can be achieved.

[0079] This means that when the distance between the common-mode and differential-mode reflection coefficients on the Smith chart is sufficiently small, the coupling between antenna ports will be significantly suppressed, thereby achieving lower coupling between antenna elements. By printing the rectangular metal strip 9 and the rectangular metal strip 10 between antenna element 5 and antenna element 6, the rectangular metal strip 9 is connected to the microstrip line 15 through the metal via 11, and the end of the microstrip line 15 is connected to the metal ground plane 17 through the metal via 16. The rectangular metal strip 10 is connected to the microstrip line 18 through the metal via 12, and the microstrip line 18 is connected to the metal ground plane 17. This effectively adjusts the distance between the common-mode and differential-mode reflection coefficients of the antenna in the two frequency bands. However, for the 3.37-3.98 GHz frequency band, the coupling between the two antenna elements is still relatively large. Based on the antenna structure described above, the second vertical microstrip structure 52 is connected to the microstrip line 20 through the metal via 22, which reduces the distance between the common-mode and differential-mode reflection coefficients of the antenna in the 3.37-3.98GHz frequency band, thereby effectively reducing the coupling between the two antenna elements.

[0080] Compared to traditional technologies, the antenna structure of this invention is simpler, significantly reducing design and manufacturing complexity, and can operate efficiently in two frequency bands: 3.37-3.98 GHz and 4.19-7.29 GHz. Secondly, by employing mode cancellation technology and introducing a specific decoupling structure, high isolation characteristics are achieved within the two operating frequency bands without occupying additional decoupling space. This not only effectively reduces mutual interference between antennas but also significantly reduces the overall size of the antenna, successfully realizing the miniaturization of the antenna system.

[0081] Furthermore, as one application example of the present invention, the horizontal dielectric substrate 1 and the vertical dielectric substrate 2 are made of FR-4 (glass fiber epoxy resin) material, with a relative permittivity of εr = 4.4, the thickness of the horizontal dielectric substrate 1 is Hs = 2 mm, and the thickness of the vertical dielectric substrate 2 is ts = 1 mm.

[0082] The dimensional parameters of a miniaturized dual-band broadband antenna based on the mode cancellation method of this invention are as follows: Figure 2 As shown in the figure, the values ​​of each parameter are as follows: Ls: 160mm; Lp1: 14mm; Lp2: 3mm; Lp3: 24mm; Ws: 80mm; Wss: 12mm; dd0: 3.5mm; dd1: 0.4mm; dd2: 0.2mm; dd3: 4mm; dz1: 1mm; Wp1: 5mm; Wp2: 2mm; Wp3: 3mm; C1: 9.5mm; C2: 3.1mm; C3: 0.2mm; Cz: 4.1mm; Cz1: 4.1mm; Cz2: 4.1mm; qq: 0.4mm; tf: 2mm.

[0083] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0084] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A miniaturized dual-band broadband MIMO antenna based on mode cancellation method, characterized in that, include: A horizontal dielectric substrate (1) and a vertical dielectric substrate (2), wherein the vertical dielectric substrate (2) is connected to one side of the long side of the horizontal dielectric substrate (1); A grounding structure is printed on the bottom of the horizontal dielectric substrate (1); Antenna (4) is printed on the vertical dielectric substrate (2); The antenna (4) includes two symmetrically arranged antenna elements. The antenna elements are printed on the vertical dielectric substrate (2). The antenna elements are connected to a microstrip feed structure. The microstrip feed structure is disposed on the horizontal dielectric substrate (1). A decoupling structure is disposed between the two antenna elements. A gap is provided between the antenna element and the decoupling structure; Both the antenna unit and the decoupling structure are grounded. The decoupling structure includes two decoupling metal strips printed between the two antenna elements. The two adjacent decoupling metal strips are parallel and spaced apart. The ends of the decoupling metal strips are spaced apart from the edges of the corresponding antenna elements. The decoupling metal strips are grounded. The antenna element has a U-shaped structure, wherein the antenna element has two horizontal segments of unequal length; The grounding structure includes: A metal floor (17) is printed on the bottom of the horizontal dielectric substrate (1); The antenna unit and the decoupling structure are both connected to the metal ground plane (17); A clearance area (3) is provided between the edge of the metal floor (17) and the vertical dielectric substrate (2); The length of the clearance area (3) is equal to the length of the metal floor (17); The two decoupling metal strips are rectangular metal strip one (9) and rectangular metal strip two (10), respectively. Rectangular metal strip one (9) and rectangular metal strip two (10) are disposed between the two antenna elements. The ends of rectangular metal strip one (9) and rectangular metal strip two (10) are left with gaps to the edges of the corresponding antenna elements. Rectangular metal strip one (9) and rectangular metal strip two (10) are spaced apart. The rectangular metal strip one (9) is grounded through metal via three (11); The rectangular metal strip two (10) is grounded through the metal via four (12); The two antenna units are antenna unit one (5) and antenna unit two (6), which are symmetrically arranged. The antenna unit one (5) and antenna unit two (6) have the same structure. The antenna unit one (5) includes a first horizontal microstrip structure (51), a second vertical microstrip structure (52) and a third horizontal microstrip structure (53) as an integral structure. The length of the third horizontal microstrip structure (53) is greater than the length of the first horizontal microstrip structure (51). The first horizontal microstrip structure (51) of the antenna unit one (5) is connected to the corresponding microstrip feed structure through a metal via two (8). The first horizontal microstrip structure (51) of the antenna unit two (6) is connected to the corresponding microstrip feed structure through a metal via one (7). The second vertical microstrip structure (52) of the first antenna unit (5) is grounded through a metal via seven (22), and the second vertical microstrip structure (52) of the second antenna unit (6) is grounded through a metal via six (21). One end of the rectangular metal strip (9) is connected to one end of the microstrip line (15) through the metal via (11), and the other end of the microstrip line (15) is connected to the metal floor (17) through the metal via (16). The rectangular metal strip 2 (10) is connected to one end of the microstrip line 2 (18) through the metal via 4 (12), and the other end of the microstrip line 2 (18) is connected to the metal floor (17); The second vertical microstrip structure (52) of the second antenna unit (6) is connected to one end of the microstrip line three (19) through the metal via six (21), and the other end of the microstrip line three (19) is connected to the metal ground plane (17); the second vertical microstrip structure (52) of the first antenna unit (5) is connected to one end of the microstrip line four (20) through the metal via seven (22), and the other end of the microstrip line four (20) is connected to the metal ground plane (17).

2. The miniaturized dual-band broadband MIMO antenna based on mode cancellation method according to claim 1, characterized in that: The microstrip feed structure includes a microstrip feed metal strip, which is disposed on the horizontal dielectric substrate (1) and connected to the corresponding antenna element.

3. A miniaturized dual-band broadband MIMO antenna based on mode cancellation method according to claim 1, characterized in that: At least one vertical dielectric substrate (2) is provided. When there is more than one antenna (4), a plurality of antennas (4) are printed on the vertical dielectric substrate (2), and two adjacent antennas (4) are spaced apart.

4. A miniaturized dual-band broadband MIMO antenna based on mode cancellation method according to claim 1, characterized in that, Both the horizontal dielectric substrate (1) and the vertical dielectric substrate (2) are made of glass fiber epoxy resin material.

5. A miniaturized dual-band broadband MIMO antenna based on mode cancellation method according to claim 1, characterized in that, The thickness of the horizontal dielectric substrate (1) is 2 mm.

6. A miniaturized dual-band broadband MIMO antenna based on mode cancellation method according to claim 1, characterized in that, The thickness of the vertical dielectric substrate (2) is 1 mm.

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