Low-coupling-frequency reconfigurable MIMO antenna

Abstract

The invention belongs to the technical field of wireless communication, and discloses a reconfigurable MIMO antenna with low coupling frequency. Comprising a dielectric substrate, and a first loading electronic component, a second loading electronic component, a third loading electronic component, a fourth loading electronic component, a fifth loading electronic component, a first tuning switch, a second tuning switch, a third tuning switch, a metalized through hole, a first central bonding pad and a second central bonding pad which are arranged on the upper layer of the dielectric substrate, the antenna comprises a first voltage bias microstrip line, a second voltage bias microstrip line, a third voltage bias microstrip line, a fourth voltage bias microstrip line, a main microstrip line, a main radiation patch, a central patch and an upper end branch patch. The lower layer of the dielectric substrate is a ground plane. According to the invention, the microstrip line is adopted for feeding, the dynamic adjustment of the working frequency of the antenna is realized through an optimized structure and a decoupling technology, meanwhile, the coupling effect between the antennas is effectively inhibited, and a high-performance antenna solution is provided for 5G communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a low-coupling frequency reconfigurable MIMO antenna. Background Art

[0002] Fifth-generation (5G) communications are centered around ultra-high speeds, ultra-low latency, and ultra-large-scale connectivity. Using technologies such as millimeter waves, massive antennas, and network slicing, they aim to enable the interconnection of everything and real-time intelligent applications. With the widespread rollout of 5G communications, the demand for high-performance antennas capable of supporting the stringent requirements of 5G applications has become even more pressing. To meet diverse application demands, antennas must support multiple frequency bands, and frequency-reconfigurable antennas are a key component in achieving this goal. Frequency-reconfigurable antennas, with their dynamic tuning capabilities, spectrum resource optimization, and compatibility with intelligent communication systems, demonstrate significant advantages in the field of new antenna technologies. This makes them irreplaceable in multi-band communication scenarios.

[0003] Compared to traditional single-input, single-output (SISO) communication systems, MIMO systems utilize multiple inputs and multiple outputs (MIMO). By placing multiple antennas at the input and output ends, they effectively suppress multipath effects and improve signal reliability and stability. They also enable more efficient signal transmission without increasing bandwidth. Replacing the antenna elements in a MIMO system with frequency-reconfigurable antennas allows the system to switch to the desired operating frequency band, expanding the system's coverage.

[0004] As antenna design becomes increasingly complex, mutual interference between MIMO antennas in limited spaces becomes more prominent. While various antenna decoupling techniques, including defective ground structure decoupling, electromagnetic bandgap structure decoupling, neutralization line and decoupling network decoupling, parasitic resonance decoupling, and spatial decoupling methods, offer good performance in specific application scenarios, these techniques are primarily designed for decoupling single-frequency antennas and suffer from drawbacks such as bulky antenna structures and limited decoupling flexibility. Summary of the Invention

[0005] The present invention aims to solve the deficiencies of the prior art and provides the following solutions:

[0006] A low-coupling frequency reconfigurable MIMO antenna comprises: a dielectric substrate, and, arranged on an upper layer of the dielectric substrate, a first loading electronic component, a second loading electronic component, a third loading electronic component, a fourth loading electronic component, a fifth loading electronic component, a first tuning switch, a second tuning switch, a third tuning switch, a metallized through hole, a first center pad, a second center pad, a first voltage bias microstrip line, a second voltage bias microstrip line, a third voltage bias microstrip line, a fourth voltage bias microstrip line, a main microstrip line, a main radiation patch, a center patch, and an upper branch patch; the lower layer of the dielectric substrate is a ground plane.

[0007] Preferably, the first voltage bias microstrip line, the second voltage bias microstrip line, the upper branch patch, the main radiation patch, the main microstrip line, the first loading electronic component, the second loading electronic component and the first tuning switch constitute a first antenna unit and a second antenna unit, and the first antenna unit and the second antenna unit are structurally symmetrically distributed on the left and right.

[0008] Preferably, one end of the first voltage bias microstrip line in the first antenna unit and the second antenna unit is connected to the first loading electronic component, the other end of the first loading electronic component is connected to the upper branch patch, the other end of the upper branch patch is connected to the first tuning switch, the other end of the first tuning switch is connected to the main radiation patch, and the main radiation patch is also connected to the second loading electronic component and the main microstrip line; the other end of the second loading electronic component is connected to the second voltage bias microstrip line.

[0009] Preferably, the main microstrip line is also connected to the second tuning switch, the other end of the second tuning switch is connected to the center patch, the center patch is also connected to the third loading electronic component and the fourth loading electronic component, the other end of the third loading electronic component is also connected to the fourth voltage bias microstrip line, the other end of the fourth loading electronic component is also connected to the first center pad, the first center pad is also connected to the third tuning switch and the fifth loading electronic component, the other end of the third tuning switch is also connected to the second center pad, the metallized through hole is located at the center of the second center pad, and the other end of the fifth loading electronic component is connected to the third voltage bias microstrip line.

[0010] Preferably, the dielectric substrate is an RO4350 laminate with a length of 60 mm, a width of 50 mm, a thickness of 1.65 mm, a dielectric constant of 3.66, and a loss tangent of 0.004;

[0011] The ground plane is a rectangular copper foil with a length of 50 mm and a width of 36 mm.

[0012] Preferably, the main microstrip line is a rectangular copper foil with a length of 1 mm and a width of 3.5 mm, the main radiation patch is a rectangular copper foil with a length of 31 mm and a width of 3.5 mm, the upper branch patch is a rectangular copper foil with a length of 11 mm and a width of 3.5 mm, and the metallized through hole is a cylindrical copper column with a radius of 0.3 mm and a height of 1.65 mm.

[0013] Preferably, the first tuning switch, the second tuning switch and the third tuning switch are all loaded with varactor diodes;

[0014] The first loading electronic component, the second loading electronic component, the third loading electronic component, the fourth loading electronic component and the fifth loading electronic component are all loaded with inductance components.

[0015] Preferably, the second voltage bias microstrip line, the second loading electronic component, the first voltage bias microstrip line and the first loading electronic component constitute a first control circuit;

[0016] The fourth voltage bias microstrip line and the third loading electronic component constitute a second control circuit;

[0017] The third voltage bias microstrip line and the fifth loading electronic component constitute a third control circuit.

[0018] Preferably, the state of the first tuning switch is changed by the first control circuit to change the current in the main radiation patch, thereby reconfiguring the operating frequency of the antenna;

[0019] The states of the second tuning switch and the third tuning switch are changed respectively by the second control circuit and the third control circuit to change the current in the main radiation patch, thereby reducing the mutual coupling between the antenna input ports.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention proposes a low-coupling frequency reconfigurable MIMO antenna. By adopting microstrip line feeding and optimizing the structure and decoupling technology, it can effectively suppress the coupling effect between antennas while achieving dynamic adjustment of the antenna operating frequency, finding the best balance between miniaturization and high performance and multi-function, and providing a high-performance antenna solution for 5G communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a schematic structural diagram of the upper layer of the dielectric substrate according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic structural diagram of the lower layer of the dielectric substrate according to an embodiment of the present invention;

[0025] Figure 3 Schematic diagram of the working principle of the antenna according to an embodiment of the present invention;

[0026] Figure 4 An annotated diagram of the upper layer of a dielectric substrate according to an embodiment of the present invention;

[0027] Figure 5 In the embodiment of the present invention Figure 4 A magnified schematic diagram of the local structure;

[0028] Figure 6 An annotated diagram of the lower layer of the dielectric substrate according to an embodiment of the present invention;

[0029] Figure 7 In the embodiment of the present invention Figure 1 Schematic diagram of the upper structure of the dielectric substrate after removing the decoupling structure;

[0030] Figure 8 For the embodiment of the present invention Figure 7 Return loss curve of the antenna;

[0031] Figure 9 For the embodiment of the present invention Figure 7 Isolation curve of the middle antenna;

[0032] Figure 10 For the embodiment of the present invention Figure 1 Return loss curve of the antenna;

[0033] Figure 11 For the embodiment of the present invention Figure 1 Isolation curve of the middle antenna;

[0034] Figure 12 For the embodiment of the present invention Figure 1 The radiation patterns of the E-plane and H-plane of the antenna in state 1;

[0035] Figure 13 For the embodiment of the present invention Figure 1 The radiation patterns of the E-plane and H-plane of the antenna in state 2;

[0036] Figure 14 For the embodiment of the present invention Figure 1 The radiation patterns of the E-plane and H-plane of the antenna in state 3;

[0037] Figure 15For the embodiment of the present invention Figure 1 ECC curve diagram of the medium antenna;

[0038] Description of reference numerals:

[0039] 1. Dielectric substrate; 2. First antenna unit; 3. Second antenna unit; 4. First voltage-biased microstrip line; 5. First loading electronic component; 6. Upper branch patch; 7. First tuning switch; 8. Main radiating patch; 9. Second voltage-biased microstrip line; 10. Second loading electronic component; 11. Third loading electronic component; 12. Second tuning switch; 13. Fourth loading electronic component; 14. Fifth loading electronic component; 15. Third tuning switch; 16. Metallized through hole; 17. Third voltage-biased microstrip line; 18. Fourth voltage-biased microstrip line; 19. Main microstrip line; 20. Ground plane; 21. Center patch; 22. First center pad; 23. Second center pad. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0041] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Example

[0043] In this embodiment, if Figure 1 、 Figure 2 As shown, a low-coupling frequency reconfigurable MIMO antenna includes: a dielectric substrate 1; and, disposed on an upper layer of the dielectric substrate 1, a first loading electronic component 5, a second loading electronic component 10, a third loading electronic component 11, a fourth loading electronic component 13, a fifth loading electronic component 14, a first tuning switch 7, a second tuning switch 12, a third tuning switch 15, a metallized through-hole 16, a first center pad 22, a second center pad 23, a first voltage bias microstrip line 4, a second voltage bias microstrip line 9, a third voltage bias microstrip line 17, a fourth voltage bias microstrip line 18, a main microstrip line 19, a main radiating patch 8, a center patch 21, and an upper branch patch 6. The lower layer of the dielectric substrate 1 is a ground plane 20. The lower layer of the dielectric substrate 1 is the ground plane 20.

[0044] The first voltage bias microstrip line 4, the second voltage bias microstrip line 9, the upper branch patch 6, the main radiation patch 8, the main microstrip line 19, the first loading electronic component 5, the second loading electronic component 10 and the first tuning switch 7 constitute the first antenna unit 2 and the second antenna unit 3. The first antenna unit 2 and the second antenna unit 3 are structurally symmetrically distributed on the left and right.

[0045] One end of the first voltage-biased microstrip line 4 in the first antenna unit 2 and the second antenna unit 3 is connected to the first loading electronic component 5. The other end of the first loading electronic component 5 is connected to the upper stub patch 6. The other end of the upper stub patch 6 is connected to the first tuning switch 7. The other end of the first tuning switch 7 is connected to the main radiating patch 8. The main radiating patch 8 is also connected to the second loading electronic component 10 and the main microstrip line 19. The other end of the second loading electronic component 10 is connected to the second voltage-biased microstrip line 99.

[0046] The main microstrip line 19 is also connected to the second tuning switch 12, the other end of the second tuning switch 12 is connected to the center patch 21, the center patch 21 is also connected to the third loading electronic component 11 and the fourth loading electronic component 13, the other end of the third loading electronic component 11 is also connected to the fourth voltage bias microstrip line 18, the other end of the fourth loading electronic component 13 is also connected to the first center pad 22, the first center pad 22 is also connected to the third tuning switch 15 and the fifth loading electronic component 14, the other end of the third tuning switch 15 is also connected to the second center pad 23, the metallized through-hole 16 is located at the center of the second center pad 23, and the other end of the fifth loading electronic component 14 is connected to the third voltage bias microstrip line 17.

[0047] The dielectric substrate 1 is an RO4350 laminate with a length of 60 mm, a width of 50 mm, a thickness of 1.65 mm, a dielectric constant of 3.66, and a loss tangent of 0.004; the ground plane 20 is a rectangular copper foil with a length of 50 mm and a width of 36 mm.

[0048] The main microstrip line 19 is a rectangular copper foil with a length of 1 mm and a width of 3.5 mm. The main radiation patch 8 is a rectangular copper foil with a length of 31 mm and a width of 3.5 mm. The upper branch patch 6 is a rectangular copper foil with a length of 11 mm and a width of 3.5 mm. The metallized through hole 16 is a cylindrical copper column with a radius of 0.3 mm and a height of 1.65 mm.

[0049] The first tuning switch 7 , the second tuning switch 12 and the third tuning switch 15 are all loaded with varactor diodes; the first loading electronic component 5 , the second loading electronic component 10 , the third loading electronic component 11 , the fourth loading electronic component 13 and the fifth loading electronic component 14 are all loaded with inductors.

[0050] The second voltage bias microstrip line 9, the second loading electronic component 10, the first voltage bias microstrip line 4 and the first loading electronic component 5 constitute a first control circuit; the fourth voltage bias microstrip line 18 and the third loading electronic component 11 constitute a second control circuit; the third voltage bias microstrip line 17 and the fifth loading electronic component 14 constitute a third control circuit.

[0051] like Figure 3 As shown in the figure, it is a schematic diagram of a low-coupling frequency reconfigurable MIMO antenna proposed in this embodiment. The state of the first tuning switch 7 is changed by the first control circuit to change the current in the main radiation patch 8, thereby reconstructing the operating frequency of the antenna; the state of the second tuning switch 12 and the third tuning switch 15 are changed by the second control circuit and the third control circuit respectively to change the current in the main radiation patch 8, thereby reducing the mutual coupling between the antenna input ports.

[0052] like Figure 4 As shown, the gap width F1 of the first loaded electronic component 5 and the gap width F3 of the second loaded electronic component 10 are both 0.6 mm, the middle pad width P1 of the first voltage bias microstrip line 4 is 1 mm, and the microstrip line length K1 is 2.2 mm, the middle pad width P2 of the second voltage bias microstrip line 9 is 1 mm, and the microstrip line length K2 is 14.4 mm, the gap width F2 of the first tuning switch 7 is 1 mm, the length L1 of the rectangular upper branch patch 6 is 11 mm, and the width W1 is 3.5 mm, the length L2 of the rectangular main radiation patch 8 is 31 mm, and the width W2 is 3.5 mm, the length L3 of the main microstrip line 19 is 1 mm, and the width W4 is 3.5 mm, and the spacing W3 between the first antenna unit 2 and the second antenna unit 3 is 7 mm.

[0053] Figure 5 Shown Figure 4 : An enlarged schematic diagram of the local structure shows that the gap width F4 of the third loaded electronic component 11, the gap width F6 of the fourth loaded electronic component 13, and the gap width F7 of the fifth loaded electronic component 14 are all 0.6 mm. The gap width F5 of the second tuning switch 12 and the gap width F8 of the third tuning switch 15 are both 1 mm. The length W5 of the rectangular pad in the middle of the second tuning switch 12 is 4.5 mm, and the width L4 is 2 mm. The pad width P3 of the fourth voltage bias microstrip line 18 is 1.6 mm. The large pad width P5 of the third voltage bias microstrip line 17 is 1.6 mm, and the small pad width P4 is 1 mm. The length K3 of the microstrip line is 6 mm, and the radius Rv of the metallized through-hole 16 is 0.3 mm.

[0054] See Figure 6 The length L0 of the dielectric substrate 11 is 60 mm, the width W0 is 50 mm, and the width Lg of the ground plane 20 is 37 mm.

[0055] Figure 7 Shown Figure 1 Schematic diagram of the upper structure of the dielectric substrate 1 of the medium and low coupling frequency reconfigurable MIMO antenna after removing the decoupling structure.

[0056] Figure 8 Shown Figure 7 Return loss curve of the mid-frequency reconfigurable MIMO antenna. The -10dB operating bandwidth of the frequency reconfigurable MIMO antenna is 2.78-3.98GHz.

[0057] Figure 9 Shown Figure 7 Isolation curve for a mid-frequency reconfigurable MIMO antenna. The isolation between antenna elements is significantly affected by the close spacing between antennas. Within the entire operating bandwidth (2.78-3.98 GHz), mutual coupling between antenna elements increases, and the overall transmission loss exceeds -14 dB.

[0058] Figure 10 Shown Figure 1 Return loss curves of the low- and medium-coupling frequency reconfigurable MIMO antenna. It can be seen that the matching and operating bandwidth of the frequency reconfigurable MIMO antenna are almost unaffected by the addition of the decoupling structure.

[0059] Figure 11 Shown Figure 1 Isolation curves for the reconfigurable MIMO antenna at low and medium coupling frequencies. Port isolation for the reconfigurable MIMO antenna within the 2.72-4.01 GHz frequency band is increased to over 20 dB. Adding a decoupling structure improves isolation performance by at least 10 dB.

[0060] See also Figure 12 , the radiation patterns of the E-plane and H-plane when the low-coupling frequency reconfigurable MIMO antenna is working in state 1. At this time, the first antenna unit 2 of the MIMO participates in the feeding, and the capacitance of the varactor diode on the first tuning switch 7 is 2.22pF, corresponding to the antenna operating frequency of 3.10GHz.

[0061] See also Figure 13 , the radiation patterns of the E-plane and H-plane when the low-coupling frequency reconfigurable MIMO antenna is working in state 2. At this time, the first antenna unit 2 of the MIMO participates in feeding, the capacitance of the varactor diode on the first tuning switch 7 is 1.3pF, and the corresponding antenna operating frequency is 3.25GHz.

[0062] See also Figure 14, the radiation patterns of the E-plane and H-plane when the low-coupling frequency reconfigurable MIMO antenna is working in state 3. At this time, the first antenna unit 2 of the MIMO participates in the feeding, the capacitance of the varactor diode on the first tuning switch 7 is 0.7pF, and the corresponding antenna operating frequency is 3.55GHz.

[0063] Figure 15 Shown Figure 1 The Envelope Correlation Coefficient (ECC) of the low-coupling frequency reconfigurable MIMO antenna is maintained below 0.14 in the 2.80-4.10 GHz frequency band.

[0064] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A low-coupling frequency reconfigurable MIMO antenna, characterized in that: include: A dielectric substrate, and a first loading electronic component, a second loading electronic component, a third loading electronic component, a fourth loading electronic component, a fifth loading electronic component, a first tuning switch, a second tuning switch, a third tuning switch, a metallized through hole, a first center pad, a second center pad, a first voltage bias microstrip line, a second voltage bias microstrip line, a third voltage bias microstrip line, a fourth voltage bias microstrip line, a main microstrip line, a main radiation patch, a center patch, and an upper end branch patch arranged on an upper layer of the dielectric substrate; the lower layer of the dielectric substrate is a ground plane.

2. The low coupling frequency reconfigurable MIMO antenna according to claim 1, characterized in that: The first voltage bias microstrip line, the second voltage bias microstrip line, the upper branch patch, the main radiation patch, the main microstrip line, the first loading electronic component, the second loading electronic component and the first tuning switch constitute a first antenna unit and a second antenna unit, and the first antenna unit and the second antenna unit are structurally symmetrically distributed on the left and right.

3. The low coupling frequency reconfigurable MIMO antenna according to claim 2, characterized in that: One end of the first voltage bias microstrip line in the first antenna unit and the second antenna unit is connected to the first loading electronic component, the other end of the first loading electronic component is connected to the upper branch patch, the other end of the upper branch patch is connected to the first tuning switch, the other end of the first tuning switch is connected to the main radiation patch, and the main radiation patch is also connected to the second loading electronic component and the main microstrip line; the other end of the second loading electronic component is connected to the second voltage bias microstrip line.

4. The low coupling frequency reconfigurable MIMO antenna according to claim 3, characterized in that: The main microstrip line is also connected to the second tuning switch, the other end of the second tuning switch is connected to the center patch, the center patch is also connected to the third loading electronic component and the fourth loading electronic component, the other end of the third loading electronic component is also connected to the fourth voltage bias microstrip line, the other end of the fourth loading electronic component is also connected to the first center pad, the first center pad is also connected to the third tuning switch and the fifth loading electronic component, the other end of the third tuning switch is also connected to the second center pad, the metallized through hole is located at the center of the second center pad, and the other end of the fifth loading electronic component is connected to the third voltage bias microstrip line.

5. The low coupling frequency reconfigurable MIMO antenna according to claim 1, characterized in that: The dielectric substrate is an RO4350 laminate with a length of 60 mm, a width of 50 mm, a thickness of 1.65 mm, a dielectric constant of 3.66, and a loss tangent of 0.004; The ground plane is a rectangular copper foil with a length of 50 mm and a width of 36 mm.

6. The low coupling frequency reconfigurable MIMO antenna according to claim 1, characterized in that: The main microstrip line is a rectangular copper foil with a length of 1 mm and a width of 3.5 mm, the main radiation patch is a rectangular copper foil with a length of 31 mm and a width of 3.5 mm, the upper branch patch is a rectangular copper foil with a length of 11 mm and a width of 3.5 mm, and the metallized through hole is a cylindrical copper column with a radius of 0.3 mm and a height of 1.65 mm.

7. The low coupling frequency reconfigurable MIMO antenna according to claim 1, characterized in that: The first tuning switch, the second tuning switch and the third tuning switch are all loaded with varactor diodes; The first loading electronic component, the second loading electronic component, the third loading electronic component, the fourth loading electronic component and the fifth loading electronic component are all loaded with inductance components.

8. The low coupling frequency reconfigurable MIMO antenna according to claim 1, characterized in that: The second voltage bias microstrip line, the second loading electronic component, the first voltage bias microstrip line and the first loading electronic component constitute a first control circuit; The fourth voltage bias microstrip line and the third loading electronic component constitute a second control circuit; The third voltage bias microstrip line and the fifth loading electronic component constitute a third control circuit.

9. The low coupling frequency reconfigurable MIMO antenna according to claim 8, characterized in that: Changing the state of the first tuning switch by the first control circuit to change the current in the main radiation patch, thereby reconfiguring the operating frequency of the antenna; The states of the second tuning switch and the third tuning switch are changed respectively by the second control circuit and the third control circuit to change the current in the main radiation patch, thereby reducing the mutual coupling between the antenna input ports.

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