A dual-band self-decoupling MIMO antenna pair

Abstract

The self-decoupling dual-band antenna pair of the present invention is suitable for the field of 5G mobile communications. It includes: three dielectric substrates, a system metal ground and four mirror-arranged antenna units. The four antenna pairs have the same physical size and are symmetrically arranged on the outside of the vertical dielectric substrate. The main part of each antenna unit is a simple and compact planar structure, consisting of a concave radiating microstrip line, two vertical radiating microstrip lines and a capacitor element. The vertical microstrip lines are located on the left and right sides of the concave radiating microstrip line respectively. The feeding part of each antenna unit consists of an I-shaped feeding branch, a via, a feeding microstrip line and a feeding port. The I-shaped feeding branch and the feeding microstrip line are connected through a via in the vertical dielectric substrate, and the feeding microstrip line is fed by the feeding port. A common ground branch is added between the two antenna units on the same side to improve the isolation between the antennas. This antenna pair has dual-frequency characteristics and can operate in the 3.5GHz and 4.8GHz~5GHz frequency bands.

Description

Technical field:

[0001] The present invention belongs to the technical field of mobile communications, relates to mobile phone antenna design, and particularly relates to a dual-frequency self-decoupling MIMO antenna pair. Background technology:

[0002] With the rapid development of modern electronic information technology and the increasing use of radio equipment, the design requirements for new terminal communication devices are constantly increasing. Antennas, as crucial front-end components in wireless communication terminal devices, have a direct impact on the quality of the entire communication system. However, with the recent increase in wireless communication devices, spectrum resources are becoming increasingly scarce, and single-band antennas can no longer meet wireless communication needs. To address this problem, multi-band antennas have emerged.

[0003] Since reducing antenna size often reduces antenna efficiency, degraded antenna performance inevitably affects the performance of the entire device system. Therefore, with the increasing demand for miniaturization and multi-frequency support in terminal devices, antenna design becomes particularly important. Miniaturization, multi-frequency support, and superior performance have become urgent challenges. Summary of the invention:

[0004] The present invention addresses the aforementioned issues with the existing technology by providing a self-decoupling dual-band antenna pair. By adding a common ground branch between the two antenna elements, high isolation between the antenna elements is achieved. Furthermore, the capacitor element enables the antenna's dual-band characteristics.

[0005] The technical solutions adopted by the present invention include: a dual-frequency self-decoupling MIMO antenna pair, including a horizontal dielectric substrate and a vertical dielectric substrate, wherein a system metal ground is printed on the lower surface of the horizontal dielectric substrate, and the vertical dielectric substrate includes two arranged on opposite side walls of the horizontal dielectric substrate, a first antenna unit and a second antenna unit are welded to the outer side of the vertical dielectric substrate on one side, and a third antenna unit and a fourth antenna unit are welded to the outer side of the vertical dielectric substrate on the other side, the first antenna unit comprises a concave radiating microstrip, a first vertical radiating microstrip, a second vertical radiating microstrip, a capacitor element, an I-shaped feeding branch, a feeding microstrip line, and a feeding port, a via is formed on the vertical dielectric substrate below the first antenna unit, the via is located below the I-shaped feeding branch, the concave radiating microstrip is located at the top of the first antenna unit, the first vertical radiating microstrip and the second vertical radiating microstrip are respectively connected to the left and right sides of the concave radiating microstrip, and the concave radiating microstrip and the first and second vertical radiating microstrips are located in the same plane, and a common ground branch is provided between the first antenna unit and the second antenna unit.

[0006] Furthermore, the first antenna unit, the second antenna unit, the third antenna unit and the fourth antenna unit have the same physical structure and the size is 9.4×7 mm. 2 .

[0007] Furthermore, the shape of the system metal ground is rectangular, and the first antenna unit and the second antenna unit, the third antenna unit and the fourth antenna unit, the first antenna unit and the fourth antenna unit, and the second antenna unit and the third antenna unit are all mirror-symmetrical about the center of the system metal ground.

[0008] Furthermore, the thickness of the horizontal dielectric substrate and the vertical dielectric substrate are both 0.8 mm, and there is a 1 mm gap between the system metal ground and both sides of the long side of the horizontal dielectric substrate.

[0009] Furthermore, the capacitor element is located inside the concave radiation microstrip and has a size of 0.55×0.5 mm. 2 .

[0010] Furthermore, the I-shaped feeding branch is located outside the vertical dielectric substrate, and the I-shaped feeding branch 1e is connected to the feeding microstrip line 1g through a via 1f.

[0011] Furthermore, the I-shaped feeding branches in the first antenna unit, the second antenna unit, the third antenna unit and the fourth antenna unit have the same size, and the width is 0.9 mm.

[0012] Furthermore, the concave radiating microstrip and the vertical dielectric substrate are on the same horizontal plane, and the sizes of the first vertical radiating microstrip and the second vertical radiating microstrip are both 6.2×0.8 mm. 2 .

[0013] Furthermore, the common ground branch is welded on the outside of the vertical dielectric substrate and is spaced 0.15 mm apart from the first antenna unit and the second antenna unit.

[0014] Furthermore, the size of the common ground branch is 0.9×3.3 mm 2 .

[0015] The present invention has the following beneficial effects:

[0016] (1) This antenna can achieve dual-band characteristics and can operate at 3500MHz and 4850MHz simultaneously, increasing the effective bandwidth of the antenna.

[0017] (2) The isolation between the two antenna units is high, achieving 20dB isolation in the 3400MHz-3600MHz frequency band and 16dB isolation between 4800MHz-5000MHz.

[0018] (3) The decoupling method is relatively simple, requiring only a shared ground terminal, which reduces the manufacturing cost of the antenna and the complexity of the decoupling circuit. Description of the drawings:

[0019] Figure 1 This is a three-dimensional structural diagram of the MIMO antenna of the present invention.

[0020] Figure 2 This is a three-dimensional structural diagram of the first antenna unit in the MIMO antenna of the present invention.

[0021] Figure 3 Schematic diagram of feeding the first antenna unit and the second antenna unit in the MIMO antenna of the present invention.

[0022] Figure 4 is the S parameter of the MIMO antenna of the present invention.

[0023] Figure 5 is the radiation efficiency of the MIMO antenna of the present invention. Specific implementation method:

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] The dual-band, self-decoupling MIMO antenna pair of the present invention comprises a horizontal dielectric substrate 7 and a vertical dielectric substrate 8. A system metal ground 6 is printed on the bottom surface of the horizontal dielectric substrate 7. The vertical dielectric substrates 8 comprise two elements disposed on opposite sidewalls of the horizontal dielectric substrate 7. A first antenna element 1 and a second antenna element 2 are soldered to the outside of one vertical dielectric substrate 8, while a third antenna element 3 and a fourth antenna element 4 are soldered to the outside of the other vertical dielectric substrate 8. The four antenna elements are identical in size and mirror-symmetric. The first antenna element 1 comprises a concave radiating microstrip 1a, a first vertical radiating microstrip 1b, a second vertical radiating microstrip 1c, a capacitive element 1d, an I-shaped feed branch 1e, a feed microstrip line 1g, and a feed port 1h. A via 1f is formed on the vertical dielectric substrate 8 below the first antenna element 1. The via 1f is located below the I-shaped feed branch 1e. The concave radiating microstrip 1a is located at the top of the first antenna unit 1, and the first vertical radiating microstrip 1b and the second vertical radiating microstrip 1c are connected to the left and right sides of the concave radiating microstrip 1a respectively, and the concave radiating microstrip 1a and the first vertical radiating microstrip 1b and the second vertical radiating microstrip 1c are located in the same plane.

[0026] The capacitor element 1d is located inside the concave radiating microstrip 1a and has a size of 0.55×0.5mm. 2 The presence of the capacitor element 1d gives the antenna dual-band characteristics. The I-shaped feeding branch 1e is located outside the vertical dielectric substrate 8 and is fed by connecting to the feeding microstrip line 1g through a via 1f passing through the vertical dielectric substrate 8.

[0027] The width of the I-shaped feeding branch in the first antenna unit and the I-shaped feeding branch in the second antenna unit are both 0.9 mm, and the I-shaped feeding branch and the antenna unit where it is located are in the same horizontal plane.

[0028] The system metal ground 6 is rectangular in shape. The first antenna unit 1 , the second antenna unit 2 , the third antenna unit 3 and the fourth antenna unit 4 are arranged outside the vertical dielectric substrate 8 and are mirror-symmetrical about the center of the system metal ground 6 .

[0029] There is a common ground branch 5 between the first antenna unit 1 and the second antenna unit 2. The common ground branch 5 is also welded on the outside of the vertical dielectric substrate 8 and is 0.15mm away from the first antenna unit 1 and the second antenna unit 2. The size of the common ground branch 5 is 0.9×3.3mm 2 , the common ground branch 5 can effectively eliminate the coupling between antennas and thus improve the isolation.

[0030] The first antenna unit 1, the second antenna unit 2, the third antenna unit 3 and the fourth antenna unit 4 have the same physical structure and are all 9.4×7 mm in size. 2 .

[0031] The thickness of the horizontal dielectric substrate 7 and the vertical dielectric substrate 8 are both 0.8 mm. There is a gap of 1 mm between the system metal ground 6 and both sides of the long side of the horizontal dielectric substrate 7 .

[0032] The concave radiating microstrip 1a is on the same horizontal plane as the vertical dielectric substrate 8. The dimensions of the first vertical radiating microstrip 1b and the second vertical radiating microstrip 1c are both 6.2×0.8 mm. 2 .

[0033] The I-shaped feeding branch 1e in the first antenna unit 1 is 0.9 mm wide and is located outside the vertical dielectric substrate 8. It has the same size as the other three I-shaped feeding branches. The I-shaped feeding branch 1e is connected to the feeding microstrip line 1g through a via 1f.

[0034] The following is a detailed example of a four-element MIMO mobile phone antenna covering the 3.5GHz and 4.85GHz frequency bands:

[0035] Figure 1 shows the three-dimensional structure of the MIMO antenna of the present invention. It comprises a horizontal dielectric substrate 7 and a system metal ground plane 6 printed on its lower surface, 1 mm from each long edge of the substrate. Two identically sized, mirror-symmetrical antenna elements, a first antenna element 1 and a second antenna element 2, are welded to the outside of a vertical dielectric substrate 8. A common ground branch 5 exists between the first and second antenna elements 1 and 2.

[0036] The structural diagram of a single antenna unit in the present invention is as follows Figure 2 As shown. Inside the concave radiating microstrip 1a, there is a capacitive element 1d with a size of 0.55×0.5mm. 2 At the same time, the concave radiating microstrip 1a is connected to the first vertical radiating microstrip 1b and the second vertical radiating microstrip 1c on the left and right. Therefore, a concave radiating microstrip, two vertical radiating microstrips and a capacitor element constitute the main part of an antenna unit.

[0037] Figure 3 Schematic diagram of the feeding of two antenna elements outside the vertical dielectric substrate 8. The distance between the I-shaped feeding branch 1e and the first vertical radiating microstrip 1b is 0.2 mm. The I-shaped feeding branch 1e is connected to the feeding microstrip line 1g through the via 1f and then fed by the feeding port 1h.

[0038] The central operating frequencies of this example are 3.5 GHz and 4.85 GHz, while the isolation is high.

[0039] Figure 4 These are the S parameters of the MIMO antenna in this example. The first resonant frequency is 3.5 GHz, with a -6dB bandwidth of approximately 7.5%. The second resonant frequency is 4.85 GHz, with a -6dB bandwidth of approximately 10.3%. Within this frequency band, the isolation between the two ports, represented by S12, reaches 20 dB at the 3.5 GHz resonant frequency and 16 dB at the 4.85 GHz resonant frequency.

[0040] Figure 5 The total efficiency of the MIMO antenna is higher than 65% when fed with excitation.

[0041] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be regarded as the scope of protection of the present invention.

Claims

1. A dual-band self-decoupling MIMO antenna pair, characterized by: The invention comprises a horizontal dielectric substrate (7) and a vertical dielectric substrate (8), wherein a system metal ground (6) is printed on the lower surface of the horizontal dielectric substrate (7), and the vertical dielectric substrate (8) comprises two elements arranged on opposite side walls of the horizontal dielectric substrate (7), wherein a first antenna unit (1) and a second antenna unit (2) are welded on the outer side of the vertical dielectric substrate (8) on one side, and a third antenna unit (3) and a fourth antenna unit (4) are welded on the outer side of the vertical dielectric substrate (8) on the other side, wherein the first antenna unit (1) comprises a concave radiating microstrip (1a), a first vertical radiating microstrip (1b), a second vertical radiating microstrip (1c), a capacitive element (1d), an I-shaped feeding branch (1e), a feeding The invention is composed of a microstrip line (1g) and a feeding port (1h); a via (1f) is formed on the vertical dielectric substrate (8) at a position below the first antenna unit (1); the via (1f) is located below the I-shaped feeding branch (1e); the concave radiating microstrip (1a) is located at the top of the first antenna unit (1); the first vertical radiating microstrip (1b) and the second vertical radiating microstrip (1c) are respectively connected to the left and right sides of the concave radiating microstrip (1a); the concave radiating microstrip (1a) and the first vertical radiating microstrip (1b) and the second vertical radiating microstrip (1c) are located in the same plane; and a common ground branch (5) exists between the first antenna unit (1) and the second antenna unit (2); The system metal ground (6) is in a rectangular shape, the first antenna unit (1) and the second antenna unit (2) are mirror-symmetrical about the center of the system metal ground (6), the third antenna unit (3) and the fourth antenna unit (4) are mirror-symmetrical about the center of the system metal ground (6), the first antenna unit (1) and the fourth antenna unit (4) are mirror-symmetrical about the center of the system metal ground (6), and the second antenna unit (2) and the third antenna unit (3) are both mirror-symmetrical about the center of the system metal ground (6); The capacitive element (1d) is located inside the concave radiation microstrip (1a) and has a size of 0.55×0.5 mm. 2 ; The I-shaped feeding branch (1e) is located outside the vertical dielectric substrate (8), and the I-shaped feeding branch (1e) is connected to the feeding microstrip line (1g) through a via (1f), and then fed by the feeding port 1h.

2. The dual-band self-decoupling MIMO antenna pair according to claim 1, wherein: The thickness of the horizontal dielectric substrate (7) and the vertical dielectric substrate (8) are both 0.8 mm, and the system metal ground (6) has a gap of 1 mm on both sides of the long side of the horizontal dielectric substrate (7).

3. The dual-band self-decoupling MIMO antenna pair according to claim 2, wherein: The I-shaped feeding branches (1e) in the first antenna unit (1), the second antenna unit (2), the third antenna unit (3) and the fourth antenna unit (4) are all of the same size, with a width of 0.9 mm.

4. The dual-band self-decoupling MIMO antenna pair according to claim 3, wherein: The concave radiation microstrip (1a) is located on the outer surface of the vertical dielectric substrate (8), and the first vertical radiation microstrip (1b) and the second vertical radiation microstrip (1c) both have dimensions of 6.2×0.8 mm. 2 .

5. The dual-band self-decoupling MIMO antenna pair according to claim 1, wherein: The common ground branch (5) is welded on the outside of the vertical dielectric substrate (8) and is spaced 0.15 mm apart from the first antenna unit (1) and the second antenna unit (2).

6. The dual-band self-decoupling MIMO antenna pair according to claim 5, wherein: The size of the common ground branch (5) is 0.9×3.3 mm 2 .

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