Low-coupling miniaturized ultra-wideband MIMO antenna

Abstract

The invention discloses a low-coupling miniaturized ultra-wideband MIMO (Multiple Input Multiple Output) antenna, which comprises a grounding plate and a plurality of antenna units arranged on the grounding plate to form an MIMO antenna, each antenna unit comprises a radiation patch and a microstrip line, the radiation patch is of a hexagonal structure formed by cutting off four corners on a rectangular base, and the microstrip line is arranged on the radiation patch. Two ends of the microstrip line are respectively connected with the edge of the radiation patch and the outer edge of the grounding plate, and the centers of the grounding plates of two adjacent antenna units extend to form I-shaped branches. Thus, the four corners of the radiation patch of the antenna unit of the MIMO antenna are cut off to form the progressive radiation surface, the size of the antenna is reduced without changing the main performance of the antenna, and the isolation of the MIMO antenna is improved by adding the grounding plate to extend the I-shaped branch knot. Therefore, the problem that the application of the MIMO antenna in the ultra-wideband field in the MIMO radar system or the wireless communication field is affected due to the insufficient isolation degree or the insufficient compactness of the size and the like is solved.

Description

Technical Field

[0001] The present invention relates to the field of ultra-wideband technology, and in particular to a low-coupling miniaturized ultra-wideband MIMO antenna. Background Art

[0002] With the development of wireless communication systems, high data rate and large system capacity have been widely studied by researchers as the goals pursued by wireless communication systems. Ultra-Wideband (UWB) technology has attracted a lot of attention from researchers due to its high data transmission rate and strong anti-interference ability. However, due to the low transmission power of ultra-wideband technology, UWB communication is widely used in the field of short-range communication, for communication, radar, positioning, tracking and other aspects.

[0003] Electromagnetic waves propagate in complex spaces, which will cause refraction and reflection, resulting in multipath effects, which will reduce the quality of communication. In order to overcome these difficulties in wireless communication, multiple-input multiple-output (MIMO) technology came into being. MIMO technology uses multiple antenna units at the transmitter and receiver at the same time, and uses diversity technology to effectively avoid multipath effects while increasing communication capacity. At present, multiple-input multiple-output technology has become a key component of the fifth-generation (5G) wireless communication system. It uses multiple antennas to overcome the impact of channel fading, improve spectrum utilization, and increase the rate of wireless communication systems, thereby improving communication quality.

[0004] As more antenna elements are added, mutual coupling between antenna elements will also affect signal quality. Due to the large bandwidth, some narrowband signals need to be filtered out. However, due to the increasing demand to accommodate more devices in a limited space, the spacing between antenna elements will be drastically reduced. This reduction in spacing will increase mutual coupling between antennas and have a negative impact on impedance matching, isolation, and correlation between elements. The mutual coupling between MIMO array elements increases dramatically, and the radiation capability and data throughput of the array are seriously affected.

[0005] Therefore, MIMO ultra-wideband antennas are mostly in the form of monopole. MIMO ultra-wideband antennas based on this form have problems such as insufficient isolation or compact size, which seriously affects the application of ultra-wideband MIMO antennas in MIMO radar systems or wireless communications. Summary of the invention

[0006] In order to solve the technical problems existing in the background technology, the present invention proposes a low-coupling miniaturized ultra-wideband MIMO antenna.

[0007] The present invention proposes a low-coupling miniaturized ultra-wideband MIMO antenna, which includes a ground plate and a plurality of antenna units arranged on the ground plate to form a MIMO antenna. Each of the antenna units includes a radiating patch and a microstrip line. The radiating patch is arranged to be a hexagonal structure formed by cutting off four corners on a rectangular basis. The two ends of the microstrip line are respectively connected to the edge of the radiating patch and the outer edge of the ground plate. An I-type branch extends from the center of the ground plate of two adjacent antenna units.

[0008] Preferably, a cross-shaped defect structure is etched on the I-type branch.

[0009] Preferably, the radiation patch is etched with CSRR inner and outer rings.

[0010] Preferably, the CSRR inner and outer loops generate notches in the frequency bands of 5.75-5.95 GHz and 7.5-7.85 GHz respectively.

[0011] Preferably, the outer loop length of the CSRR inner and outer loops is set to half the guided wavelength corresponding to 5.8 GHz to obtain a notch with a frequency band of 5.75-5.95 GHz; the inner loop length of the CSRR inner and outer loops is set to half the guided wavelength corresponding to 7.8 GHz to obtain a notch with a frequency band of 7.5-7.85 GHz.

[0012] Preferably, optimization is performed using HFSS software to obtain appropriate dimensions of the antenna.

[0013] Preferably, the antenna unit is a planar monopole antenna.

[0014] Preferably, the MIMO antenna covers a frequency band ranging from 3.1 to 10.6 GHz.

[0015] Preferably, the MIMO antenna achieves an isolation greater than -20 dB within its operating frequency band.

[0016] In summary, the present invention has the following beneficial effects: the radiation patch of the antenna unit of the MIMO antenna cuts off four corners to form a progressive radiation surface, which reduces the size of the antenna without changing the main performance of the antenna, and then increases the ground plate to extend the I-type branch, thereby improving the isolation of the MIMO antenna. In this way, the application of the MIMO antenna in the ultra-wideband field in the MIMO radar system or the wireless communication field will not be affected by problems such as insufficient isolation or insufficient compactness.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1is a structural schematic diagram of an existing antenna unit;

[0019] Figure 2 A schematic diagram of the structure of a low-coupling miniaturized ultra-wideband MIMO antenna according to an embodiment of the present invention

[0020] Figure 3 This is a schematic diagram of an I-type branch structure extending from a base plate in an embodiment of the present invention;

[0021] Figure 4 A schematic diagram of the structure of a cross-shaped defect etched in an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the overall MIMO antenna structure in which the radiation patch etches the inner and outer rings of the CSRR in an embodiment of the present invention;

[0023] Figure 6 This is a current distribution diagram of the MIMO antenna near 5.5 GHz in an embodiment of the present invention;

[0024] Figure 7 This is a current distribution diagram of the MIMO antenna at 7.5 GHz in an embodiment of the present invention;

[0025] Figure 8 A voltage return loss curve diagram in an embodiment of the present invention;

[0026] Fig. 9 It is an isolation curve diagram in an embodiment of the present invention;

[0027] Fig.10 A voltage standing wave ratio curve diagram in an embodiment of the present invention;

[0028] Fig.11 Graph showing antenna envelope correlation coefficient in an embodiment of the present invention.

[0029] In the figure:

[0030] 1. Ground plate; 2. Antenna unit; 3. Radiating patch; 4. Microstrip line; 5. I-type branch; 6. Cross-shaped defect ground structure; 7. CSRR inner and outer rings. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0032] like Figure 2-11As shown, a low-coupling miniaturized ultra-wideband MIMO antenna proposed in this embodiment includes a ground plate 1 and a plurality of antenna units 2 arranged on the ground plate 1 to form a MIMO antenna, each antenna unit 2 includes a radiation patch 3 and a microstrip line 4, the radiation patch 3 is set to be a hexagonal structure formed by cutting off four corners on the basis of a rectangle, the two ends of the microstrip line 4 are respectively connected to the edge of the radiation patch 3 and the outer edge of the ground plate 1, and an I-type branch 5 extends from the center of the ground plate 1 of two adjacent antenna units 2.

[0033] Specifically, the MIMO antenna in this embodiment includes two antenna units 2. Of course, the number of antenna units 2 can also be other numbers, depending on the actual situation. It should be noted that the antenna unit in this embodiment adopts a planar monopole antenna, which has the characteristics of low profile, small size and wide bandwidth.

[0034] In this way, the radiation patch 3 of the antenna unit of the MIMO antenna in this embodiment cuts off four corners to form a progressive radiation surface, reducing the size of the antenna without changing the main performance of the antenna, and then using the ground plate 1 to extend the I-type branch 5 to improve the isolation of the MIMO antenna. In this way, the application of the MIMO antenna in the ultra-wideband field in the MIMO radar system or wireless communication field will not be affected by problems such as insufficient isolation or insufficient compact size. .

[0035] Furthermore, if Figure 3 and Figure 4 As shown, a cross-shaped defect ground structure 6 is etched on the I-type branch 5 to further improve the isolation of the antenna. The MIMO antenna in this embodiment covers a frequency band of 3.1-10.6 GHz, and an isolation greater than -20 dB can be obtained within the working frequency band.

[0036] Furthermore, if Figure 5 As shown, the radiation patch 3 is etched with CSRR inner and outer rings 7. The CSRR inner and outer rings 7 generate notches with frequency bands of 5.75-5.95 GHz and 7.5-7.85 GHz respectively. The outer ring length of the CSRR inner and outer rings 7 is approximately set to half of the guided wavelength corresponding to 5.8 GHz to obtain a notch with a frequency band of 5.75-5.95 GHz. The value is calculated to be 16.1 mm, and the actual simulation value is 16 mm; the inner ring length of the CSRR inner and outer rings 7 is approximately set to half of the guided wavelength corresponding to 7.8 GHz to obtain a notch with a frequency band of 7.5-7.85 GHz. The calculated value is 12.1 mm, and the simulation value is 12 mm, thereby obtaining a double notch characteristic in this frequency band. When the antenna works at 5.75-5.9 GHz and 7.5-7.85 GHz respectively, a large amount of current accumulates near the outer outer and inner rings of the CSRR inner and outer rings, making it impossible for the antenna to radiate, so a notch characteristic is formed here.

[0037] In this embodiment, HFSS (High Frequency Structure Simulator 3D electromagnetic simulation software) software is used for optimization to obtain appropriate dimensions of the antenna. Figure 4 and Figure 5 The specific dimensions of the antenna shown are as follows: W1=10mm, W2=1mm, W4=14mm, W5=6mm, W6=2.2mm, W7=34mm, W8=2.25mm, W9=0.5mm, L1=4.1mm, L2=1mm, L4=14mm, L4=4mm, L5=6.5mm, L6=7.4mm, G1=4.4mm, L7=24mm, L8=2.85mm, R1=4mm, R2=2mm.

[0038] It should be noted that if Fig.10 and Fig.11 As shown, the MIMO antenna performance parameters in this embodiment are less than 2 in the entire UWB (ultra-wideband) band (except that the voltage standing wave ratio in the two notch bands is greater than 2), and the envelope correlation coefficient is below 0.05, which is far less than the requirement of ECC<0.5.

[0039] In summary, the MIMO antenna in this embodiment is a small-size compact ultra-wideband antenna of 34mm×24mm in size. The MIMO antenna covers the ultra-wideband (3.1-10.6GHz) frequency band and obtains an isolation greater than -20dB in the entire operating frequency band, and has notch characteristics in the two frequency bands of 5.75-5.95GHz and 7.5-7.85GHz.

[0040] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A low-coupling miniaturized ultra-wideband MIMO antenna, comprising a ground plane and a plurality of antenna units arranged on the ground plane to form a MIMO antenna, characterized in that: Each of the antenna units includes a radiation patch and a microstrip line. The radiation patch is arranged to be a hexagonal structure formed by cutting off four corners on a rectangular basis. The two ends of the microstrip line are respectively connected to the edge of the radiation patch and the outer edge of the ground plate. An I-type branch extends from the center of the ground plate of two adjacent antenna units.

2. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 1, characterized in that: A cross-shaped defect structure is etched on the I-type branch.

3. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 1, characterized in that: The radiation patch is etched with CSRR inner and outer rings.

4. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 3, characterized in that: The CSRR inner and outer loops generate notches in the frequency bands of 5.75-5.95 GHz and 7.5-7.85 GHz respectively.

5. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 4, characterized in that: The outer loop length of the CSRR inner and outer loops is set to 5.8 GHz, which corresponds to half the guided wavelength, to obtain a notch with a frequency band of 5.75-5.95 GHz; the inner loop length of the CSRR inner and outer loops is set to 7.8 GHz, which corresponds to half the guided wavelength, to obtain a notch with a frequency band of 7.5-7.85 GHz.

6. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 1, characterized in that: HFSS software is used to optimize the antenna to obtain the appropriate dimensions.

7. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 1, characterized in that: The antenna unit adopts a planar monopole antenna.

8. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 1, characterized in that: The MIMO antenna covers a frequency band ranging from 3.1 to 10.6 GHz.

9. The low-coupling miniaturized ultra-wideband MIMO antenna according to claim 8, characterized in that: The MIMO antenna achieves an isolation greater than -20 dB within its operating frequency band.

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