A low-coupling frequency reconfigurable MIMO antenna

Abstract

This invention belongs to the field of wireless communication technology and discloses a low-coupling frequency reconfigurable MIMO antenna, 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 metallized via, 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 radiating patch, a center patch, and an upper stub patch; the lower layer of the dielectric substrate is a ground plane. This invention uses microstrip line feeding and, through optimized structure and decoupling technology, effectively suppresses the coupling effect between antennas while achieving dynamic adjustment of the antenna operating frequency, providing a high-performance antenna solution for 5G communication.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and specifically relates to a low-coupling frequency reconfigurable MIMO antenna. Background Technology

[0002] Fifth-generation (5G) communication, centered on ultra-high speed, ultra-low latency, and ultra-large-scale connectivity, utilizes technologies such as millimeter waves, massive MIMO, and network slicing to achieve the Internet of Things and real-time intelligent applications. With the widespread adoption of 5G communication, the demand for high-performance antennas capable of supporting the stringent requirements of 5G applications has become increasingly urgent. To meet diverse application needs, antennas must support multiple frequency bands, and frequency-reconfigurable antennas are crucial components for achieving this goal. Frequency-reconfigurable antennas, with their dynamic tuning capabilities, spectrum resource optimization characteristics, and adaptability to intelligent communication systems, demonstrate significant advantages in the field of new antenna technology, making them irreplaceable in multi-band communication scenarios.

[0003] Compared to traditional single-input single-output (SSO) communication systems, MIMO systems are multiple-input multiple-output (MIMO) systems. By placing multiple antennas at the input and output terminals, they can effectively suppress multipath effects, improve signal reliability and stability, and transmit more signals without expanding the signal bandwidth, achieving highly efficient signal transmission. Replacing the antenna elements in a MIMO system with frequency-reconfigurable antennas allows switching to the required operating frequency band according to the MIMO system, thus increasing the system's operating frequency coverage.

[0004] As antenna designs become increasingly complex, the problem of mutual interference between MIMO antennas in limited spaces becomes more prominent. Various antenna decoupling techniques, including defective ground structure decoupling, electromagnetic bandgap structure decoupling, neutral line and decoupling network decoupling, parasitic resonance decoupling, and spatial decoupling methods, perform well in specific applications. However, these techniques are mostly designed for single-frequency antennas and suffer from drawbacks such as large antenna structure size and low decoupling flexibility. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing technologies and provides the following solutions:

[0006] A low-coupling frequency reconfigurable MIMO antenna includes: 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 via, 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 radiating patch, a center patch, and an upper stub patch, disposed on the upper layer of the dielectric substrate; 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 stub patch, the main radiating patch, the main microstrip line, the first loading electronic component, the second loading electronic component, and the first tuning switch constitute the first antenna unit and the second antenna unit, which are symmetrically distributed left and right in structure.

[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 stub patch, the other end of the upper stub patch is connected to the first tuning switch, the other end of the first tuning switch is connected to the main radiating patch, and the main radiating 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 via 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 60mm, a width of 50mm, a thickness of 1.65mm, a dielectric constant of 3.66, and a tangent loss angle of 0.004.

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

[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 radiating 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 via is a cylindrical copper pillar 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 loaded electronic component, the second loaded electronic component, the third loaded electronic component, the fourth loaded electronic component, and the fifth loaded electronic component are all loaded with inductors.

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

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

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

[0018] Preferably, the current in the main radiating patch is changed by changing the state of the first tuning switch through the first control circuit, thereby reconstructing the operating frequency of the antenna.

[0019] By changing the states of the second and third tuning switches respectively through the second and third control circuits, the current in the main radiating patch is altered, thereby reducing the mutual coupling between the antenna input ports.

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

[0021] This invention proposes a low-coupling frequency reconfigurable MIMO antenna. By employing microstrip line feeding and optimizing the structure and decoupling technology, it achieves dynamic adjustment of the antenna's operating frequency while effectively suppressing the coupling effect between antennas. It finds the optimal balance between miniaturization, high performance, and multifunctionality, providing a high-performance antenna solution for 5G communication. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced 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.

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

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

[0025] Figure 3 This is a schematic diagram illustrating the working principle of the antenna in an embodiment of the present invention;

[0026] Figure 4 This is an annotation diagram of the upper layer of the dielectric substrate according to an embodiment of the present invention;

[0027] Figure 5 As described in the embodiments of the present invention Figure 4 A magnified schematic diagram of a local structure;

[0028] Figure 6 This is an annotation diagram of the lower layer of the dielectric substrate according to an embodiment of the present invention;

[0029] Figure 7 As described in the embodiments of the present invention Figure 1 A schematic diagram of the upper layer structure of the dielectric substrate after removing the decoupling structure;

[0030] Figure 8 This is an embodiment of the present invention. Figure 7 Return loss curve of the antenna;

[0031] Figure 9 This is an embodiment of the present invention. Figure 7 Isolation curve of the antenna;

[0032] Figure 10 This is an embodiment of the present invention. Figure 1 Return loss curve of the antenna;

[0033] Figure 11 This is an embodiment of the present invention. Figure 1 Isolation curve of the antenna;

[0034] Figure 12 This is an embodiment of the present invention. Figure 1 Radiation patterns of the E-plane and H-plane when the antenna is operating in state 1;

[0035] Figure 13 This is an embodiment of the present invention. Figure 1 Radiation patterns of the E-plane and H-plane when the antenna is operating in state 2;

[0036] Figure 14 This is an embodiment of the present invention. Figure 1 Radiation patterns of the E-plane and H-plane when the antenna is operating in state 3;

[0037] Figure 15This is an embodiment of the present invention. Figure 1 ECC curve of the antenna;

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Dielectric substrate; 2. First antenna element; 3. Second antenna element; 4. First voltage-biased microstrip line; 5. First loading electronic component; 6. Upper stub 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 via; 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 Implementation

[0040] 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.

[0041] 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.

[0042] Example

[0043] In this embodiment, as Figure 1 , Figure 2 As shown, a low-coupling frequency reconfigurable MIMO antenna includes: a dielectric substrate 1, and 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 via 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 stub patch 6 disposed on the upper layer of the dielectric substrate 1; the lower layer of the dielectric substrate 1 is a ground plane 20.

[0044] The first voltage bias microstrip line 4, the second voltage bias microstrip line 9, the upper stub patch 6, the main radiating 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 symmetrically distributed from left to right in structure.

[0045] One end of the first voltage bias 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 bias 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 via 16 is located at the center of the second center pad 23. 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 60mm, a width of 50mm, a thickness of 1.65mm, a dielectric constant of 3.66, and a tangent loss angle of 0.004; the ground plane 20 is a rectangular copper foil with a length of 50mm and a width of 36mm.

[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 radiating 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, and the metallized via 16 is a cylindrical copper pillar 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 loaded electronic component 5, the second loaded electronic component 10, the third loaded electronic component 11, the fourth loaded electronic component 13, and the fifth loaded 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 the first control circuit; the fourth voltage bias microstrip line 18 and the third loading electronic component 11 constitute the second control circuit; and the third voltage bias microstrip line 17 and the fifth loading electronic component 14 constitute the third control circuit.

[0051] like Figure 3 The diagram shown is a schematic of a low-coupling frequency reconfigurable MIMO antenna proposed in this embodiment. The first control circuit changes the state of the first tuning switch 7 to change the current in the main radiating patch 8, thereby reconfiguring the antenna's operating frequency. The second and third control circuits change the states of the second tuning switch 12 and the third tuning switch 15, respectively, to change the current in the main radiating 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 loading electronic component 5 and the gap width F3 of the second loading electronic component 10 are both 0.6 mm. The width P1 of the middle pad of the first voltage bias microstrip line 4 is 1 mm, and the microstrip line length K1 is 2.2 mm. The width P2 of the middle pad 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 stub patch 6 is 11 mm, and the width W1 is 3.5 mm. The length L2 of the rectangular main radiating 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. The spacing W3 between the first antenna element 2 and the second antenna element 3 is 7 mm.

[0053] Figure 5 It shows Figure 4 The enlarged schematic diagram of the partial structure shows that the gap width F4 of the third loading electronic component 11, the gap width F6 of the fourth loading electronic component 13, and the gap width F7 of the fifth loading 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, 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 via 16 is 0.3 mm.

[0054] Please see Figure 6 The dielectric substrate 11 has a length L0 of 60 mm, a width W0 of 50 mm, and a ground plane 20 has a width Lg of 37 mm.

[0055] Figure 7 It shows Figure 1 A schematic diagram of the upper layer structure of the dielectric substrate 1 after removing the decoupling structure of the medium-low coupling frequency reconfigurable MIMO antenna.

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

[0057] Figure 9 It shows Figure 7 Isolation curves for mid-frequency reconfigurable MIMO antennas. The isolation between antenna elements is significantly affected by the close spacing between them. Throughout the operating bandwidth (2.78-3.98 GHz), the mutual coupling between antenna elements becomes stronger, and the overall transmission loss is higher than -14 dB.

[0058] Figure 10 It shows Figure 1 The return loss curve of a frequency-reconfigurable MIMO antenna with low to medium coupling frequency is shown. It can be seen that the matching and operating bandwidth of the frequency-reconfigurable MIMO antenna are almost unaffected after the decoupling structure is applied.

[0059] Figure 11 It shows Figure 1 Isolation curves for reconfigurable MIMO antennas with low to medium coupling frequencies. Port isolation for reconfigurable MIMO antennas in the 2.72–4.01 GHz band is improved to over 20 dB. After adding a decoupling structure, isolation performance is improved by at least 10 dB.

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

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

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

[0063] Figure 15 It shows Figure 1 Envelope Correlation Coefficient (ECC) of reconfigurable MIMO antennas with low-to-medium coupling frequencies. In the 2.80-4.10 GHz band, the ECC of reconfigurable MIMO antennas with low coupling frequencies remains below 0.14.

[0064] 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 to the technical solutions of the present invention by those skilled in the art 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 low-coupling frequency reconfigurable MIMO antenna, characterized in that, include: The 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 via, 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 radiating patch, a center patch, and an upper stub patch disposed on the upper layer of the dielectric substrate; The lower layer of the dielectric substrate is the ground plane; The first voltage bias microstrip line, the second voltage bias microstrip line, the upper stub patch, the main radiating patch, the main microstrip line, the first loading electronic component, the second loading electronic component, and the first tuning switch constitute the first antenna unit and the second antenna unit, which are symmetrically distributed left and right in structure. One end of the first voltage-biased 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 stub patch, the other end of the upper stub patch is connected to the first tuning switch, the other end of the first tuning switch is connected to the main radiating patch, and the main radiating 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-biased microstrip line. 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 via is located at the center of the second center pad. The other end of the fifth loading electronic component is connected to the third voltage bias microstrip line.

2. 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 60mm, a width of 50mm, a thickness of 1.65mm, a dielectric constant of 3.66, and a tangent loss angle of 0.

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

3. 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 radiating 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 via is a cylindrical copper pillar with a radius of 0.3 mm and a height of 1.65 mm.

4. 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 loaded electronic component, the second loaded electronic component, the third loaded electronic component, the fourth loaded electronic component, and the fifth loaded electronic component are all loaded with inductors.

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

6. The low-coupling frequency reconfigurable MIMO antenna according to claim 5, characterized in that, The first control circuit changes the state of the first tuning switch to change the current in the main radiating patch, thereby reconstructing the antenna's operating frequency. By changing the states of the second and third tuning switches respectively through the second and third control circuits, the current in the main radiating patch is altered, thereby reducing the mutual coupling between the antenna input ports.

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