Ultra-wideband MIMO antenna

Abstract

The invention is suitable for the technical field of wireless communication, and provides an ultra-wideband MIMO antenna, which comprises a dielectric substrate; the four antenna units are distributed on the front surface of the dielectric substrate in a central symmetry manner, and each antenna unit comprises a radiation patch and a microstrip feeder connected with the radiation patch; the antenna unit also comprises a DGS grounding plate, and the DGS grounding plate is disposed on the back surface of the dielectric substrate. Wherein each radiation patch is etched with a trapezoidal groove and a bent arch door-shaped groove which are used for realizing a wave trapping function and broadband coverage; an I-shaped groove is etched in the DGS grounding plate; moreover, a splayed branch knot is connected between the DGS grounding plate areas corresponding to the two antenna units located at the diagonal positions, and the antenna has the characteristics of low profile, light weight and easy conformality, and is suitable for high-speed motion carrier integration.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, specifically to an ultra-wideband MIMO antenna. Background Technology

[0002] As modern wireless communication systems evolve towards broadband, high capacity, and high reliability, the combination of ultra-wideband (UWB) technology and multiple-input multiple-output (MIMO) architecture has become an important means to improve communication speed and reliability. On mobile platforms such as drones and high-speed aircraft, antennas not only need to have wide bandwidth coverage, but also need to achieve high isolation of multiple channels within a limited space, and avoid co-channel interference with existing systems in complex electromagnetic environments.

[0003] Currently, the design of MIMO antennas for missile-borne, airborne, and other scenarios still faces the following three key challenges: 1) Severe coupling between MIMO channels and strong mutual coupling between antenna elements lead to reduced isolation (often below 10dB), affecting the spatial multiplexing gain and channel capacity of the MIMO system; 2) Lack of frequency band suppression capability, lack of active suppression mechanism for specific interference frequency bands (such as satellite uplink frequency band), which can easily cause interference within or between systems; 3) Limitations of ground plane design: Although common complete ground planes are easy to process, they limit the flexibility of impedance matching and make it difficult to achieve good matching and radiation efficiency improvement in the ultra-wideband range.

[0004] Therefore, in view of the above situation, there is an urgent need to provide an ultra-wideband MIMO antenna to overcome the shortcomings in current practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-wideband MIMO antenna, which aims to solve the problems mentioned in the background art.

[0006] This invention is implemented as follows: an ultra-wideband MIMO antenna, comprising: Dielectric substrate; Four antenna elements are centrally symmetrically distributed on the front side of the dielectric substrate. Each antenna element includes a radiating patch and a microstrip feed line connected to the radiating patch. The antenna unit further includes a DGS ground plane, which is disposed on the back side of the dielectric substrate; Each of the radiating patches is etched with trapezoidal slots and curved arch slots to achieve notch filtering and broadband coverage. The DGS ground plane is etched with I-shaped grooves; Furthermore, a figure-eight stub connects the DGS ground plane regions corresponding to the two antenna elements located diagonally.

[0007] As a further aspect of the present invention: the antenna operates over two consecutive widebands, 5.2GHz-13.2GHz and 14.5GHz-16.3GHz, and has notch characteristics in the 13.2GHz-14.5GHz band.

[0008] As a further aspect of the present invention, the width of the trapezoidal groove gradually increases from 0.3 mm to 0.9 mm.

[0009] As a further aspect of the present invention, the microstrip feeder has a trapezoidal structure.

[0010] As a further aspect of the present invention: the figure-eight branches consist of four sections, symmetrically arranged between the DGS ground plane areas corresponding to each pair of antenna elements located at diagonal positions.

[0011] As a further aspect of the present invention, the dielectric substrate is made of FR4 material.

[0012] As a further aspect of the present invention, the overall dimensions of the dielectric substrate are 36mm × 36mm × 1.635mm.

[0013] As a further aspect of the present invention: the dielectric constant of the FR4 material is 4.4 and the thickness is 1.6 mm.

[0014] As a further aspect of the present invention: the isolation parameter S between the antenna elements 21 S 31 S 41 The value is above 15dB in the 5-16GHz frequency band.

[0015] As a further aspect of the present invention, the depth of the notch filter in the 13.2-14.5 GHz frequency band exceeds -5 dB.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention features dual broadband coverage, with the antenna having an S11 < -10dB in both the 5.2-13.2GHz and 14.5-16.3GHz frequency bands, meeting the comprehensive requirements of ultra-wideband communication, radar sensing, and satellite data links.

[0017] 2. This invention has high isolation performance, with an isolation ratio (S) between antenna elements. 21 S 31 S 41 The efficiency is above 15dB across the entire 5–16GHz frequency band, effectively suppressing channel mutual coupling and improving the spectral efficiency of the MIMO system.

[0018] 3. The present invention has a compact structure and is easy to integrate. It adopts a single-layer microstrip structure and defective ground design, resulting in a low antenna profile and light weight, making it suitable for conformal mounting on the surface of aircraft.

[0019] 4. This invention can achieve precise notch suppression, enabling adjustable notch filtering in the 13.2-14.5GHz frequency band with a depth exceeding -5dB, avoiding interference to Ku-band satellite communication and other systems, and improving electromagnetic compatibility.

[0020] 5. This invention has good radiation characteristics, with the antenna gain reaching up to 5dBi in the passband and a stable radiation pattern, making it suitable for omnidirectional communication in high-speed mobile scenarios. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is the front view of a single antenna element structure provided in the embodiments of the present invention; Figure 2 This is a side view of a single antenna element structure provided in the embodiments of the present invention; Figure 3 This is a 3D schematic diagram of a single antenna element structure provided in an embodiment of the present invention, (a) being the front and (b) being the back. Figure 4 This is the front view of the ultra-wideband MIMO antenna provided in this embodiment of the invention; Figure 5 This is the side view of the ultra-wideband MIMO antenna provided in this embodiment of the invention; Figure 6 This is a 3D schematic diagram of the ultra-wideband MIMO antenna provided in an embodiment of the present invention, (a) is the front side, and (b) is the back side; Figure 7 This is a comparison diagram of S11 curves between different antenna elements provided in the embodiments of the present invention; Figure 8 This is a schematic diagram of the S11 curve of the ultra-wideband MIMO antenna provided in an embodiment of the present invention; Figure 9 This is a comparison chart of S-parameter curves of the ultra-wideband MIMO antenna with and without figure-eight stubs provided in the embodiments of the present invention; Figure 10 This is the radiation pattern of the ultra-wideband MIMO antenna in the E-plane and H-plane at 6 GHz provided in this embodiment of the invention; Figure 11 This is the radiation pattern of the ultra-wideband MIMO antenna in the E-plane and H-plane at 8 GHz provided in this embodiment of the invention; Figure 12 This is the radiation pattern of the ultra-wideband MIMO antenna in the E-plane and H-plane at 12 GHz, provided in an embodiment of the present invention.

[0023] In the attached diagram: 1-Radiating patch, 2-Dielectric substrate, 3-Microstrip feeder, 4-I-shaped groove, 5-DGS ground plane, 6-Figure-eight stub. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0025] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] The present invention will be further explained below with reference to specific embodiments.

[0028] Please see Figures 1-12This invention provides an ultra-wideband MIMO antenna with a four-element MIMO layout, operating in two consecutive widebands: 5.2GHz-13.2GHz and 14.5GHz-16.3GHz, with relative bandwidths of 87.3% and 11.9%, respectively. By designing a slot structure and pruning stubs on the radiating patch 1, a notch filter function is implemented in the 13.2GHz-14.5GHz band, effectively suppressing radiation in this band. The ground plane employs a defective ground structure (DGS) with I-beam grooves, and small figure-eight stubs are added between the cross-ground planes, thereby significantly improving bandwidth and enhancing inter-element isolation.

[0029] Ultra-wideband MIMO antennas specifically include: Dielectric substrate 2; Four antenna elements are centrally symmetrically distributed on the front side of the dielectric substrate 2. Each antenna element includes a radiating patch 1 and a 50Ω microstrip feed line 3 connected to the radiating patch 1. DGS ground plane 5, wherein the DGS ground plane 5 is disposed on the back side of the dielectric substrate 2; Each of the radiating patches 1 is precision-etched with trapezoidal and arch-shaped slots to achieve notch filtering and broadband coverage. The slot structure is equivalent to a series LC resonant circuit in the target frequency band, achieving electromagnetic wave reflection and energy suppression. An arch-shaped pruning technique is used in the middle of the radiating patch 1 to further perturb the surface current distribution, enhancing the notch depth and bandwidth, while simultaneously optimizing impedance matching and radiation efficiency within the passband. By introducing the arch-shaped pruning method, multiple resonant modes can be excited, thereby significantly expanding the antenna's impedance bandwidth. Furthermore, the structural design of the trapezoidal microstrip feed line 3 further optimizes energy transmission and impedance matching, laying a crucial foundation for improving the overall antenna performance. The DGS ground plane 5 is etched with an I-shaped slot 4. This design allows for adjustment of the current path of the DGS ground plane 5, expanding the antenna impedance bandwidth and improving the inter-element isolation to over 15dB in the 5-16GHz frequency band. While reducing the antenna weight and complexity, the I-shaped slot 4 effectively controls the electromagnetic field distribution in the DGS ground plane 5 region by replanning the ground current path, thereby further broadening the antenna's impedance range in the S-band. 11 The operating bandwidth at <-10dB significantly improves wideband performance; Furthermore, a figure-eight stub 6 connects the DGS ground plane 5 regions corresponding to the two antenna elements located diagonally, without affecting the S 21 and S 41 In the case of increasing S 31 This value increases the isolation between non-orthogonal antenna elements.

[0030] In a more specific example, the antenna operates over two consecutive widebands: 5.2 GHz to 13.2 GHz and 14.5 GHz to 16.3 GHz, and has notch characteristics in the 13.2 GHz to 14.5 GHz band.

[0031] In a more specific example, the width of the trapezoidal slot gradually increases from 0.3 mm to 0.9 mm, and its length is optimized according to the 13.2-14.5 GHz notch band.

[0032] In a more specific example, the figure-eight branches 6 are four in number, symmetrically arranged between the DGS ground plane 5 regions corresponding to each pair of antenna elements located diagonally.

[0033] In a more specific example, the dielectric substrate 2 is made of FR4 material; The overall dimensions of the dielectric substrate 2 are 36mm × 36mm × 1.635mm; The FR4 material has a dielectric constant of 4.4 and a thickness of 1.6 mm.

[0034] In a more specific example, the isolation parameter S between the antenna elements 21 S 31 S 41 The value is above 15dB in the 5-16GHz frequency band.

[0035] In a more specific example, the notch has a depth exceeding -5 dB in the 13.2–14.5 GHz band.

[0036] This invention uses the electromagnetic full-wave simulation software CST to simulate, analyze, and optimize the ultra-wideband MIMO antenna, and studies its structural parameters, S11 parameters, and radiation pattern.

[0037] like Figure 7 As shown, ANT1 is the most basic patch antenna design. ANT2 is derived from ANT1 by cutting out the ground plane, specifically by cutting an I-shaped slot into the complete ground plane. ANT3 is derived from the upper radiating surface of ANT2 by cutting out two trapezoidal slots diagonally on the upper surface and a curved arch-shaped slot in the middle. The S-shaped slot of the ANT3 antenna element (with slotting)... 11 The parameters are all less than -10dB in the range of 5GHz-14.3GHz and 16.1GHz-17.5GHz, with relative bandwidths of 96.37% and 8.33% respectively. The reflection coefficients are relatively low and good impedance matching is maintained. Compared with the ant1 and ant2 antenna elements, the ant3 antenna element can not only shift the coverage frequency down, but also has excellent notch filtering effect. Therefore, ant3 is used as the basic unit of MIMO antenna.

[0038] like Figure 8 As shown, the S of this MIMO antenna 11 The parameters are all less than -10dB in the ranges of 5.2GHz-13.2GHz and 14.5GHz-16.3GHz, with relative bandwidths of 86.95% and 11.69% respectively. The reflection coefficients are relatively low and good impedance matching is maintained, thus the antenna has ultra-wideband characteristics.

[0039] Figure 9 A comparison of the S-parameters of a MIMO antenna without a 6-stub and a MIMO antenna with a 6-stub is presented. The S-parameters of the two antennas are... 21 The parameters are all less than -15dB within the 4GHz-18GHz range, with Ant2 even reaching as low as -36dB, demonstrating the antenna's high isolation; however, Ant1, without its figure-eight stub, has a S... 31 The parameters did not meet the requirement of being less than -15dB across the entire frequency band, but adding four figure-eight stubs to Ant2 could meet the S requirement. 31 The parameters are all less than -15dB within the 4GHz-18GHz range, indicating that adding the figure-eight stub 6 significantly increases the isolation between MIMO antenna elements. Therefore, Ant2 is adopted as the final MIMO antenna configuration.

[0040] Figures 10-12 The E-plane and H-plane radiation patterns of this invention at different frequencies within the operating frequency band are presented. The patterns show that at low frequencies, the antenna exhibits a figure-eight shape in the E-plane and a circular shape in the H-plane, demonstrating good omnidirectional performance and the ability to transmit and receive signals from all directions. At high frequencies, the E-plane radiation pattern remains figure-eight, while the H-plane radiation pattern shows slight distortion. Specifically... Figure 10 The radiation patterns of the E-plane and H-plane at 6 GHz; Figure 11 The radiation patterns of the E-plane and H-plane at 8 GHz; Figure 12 The radiation patterns are for the E-plane and H-plane at 12 GHz.

[0041] In summary, this invention provides an ultra-wideband MIMO antenna with notch filtering function, suitable for high-speed moving platforms such as missile-borne and airborne systems.

[0042] This invention has a simple structure and does not require an external filter, which promotes the diversified distribution of antenna resonant points, thereby endowing the antenna with dual broadband and notch filter integrated characteristics.

[0043] Meanwhile, by adopting an orthogonal layout and defective ground combination design, and optimizing the surface current distribution through DGS ground plane etching pattern, the mutual coupling between units is minimized, achieving an isolation of more than 15dB across the entire 5-16GHz frequency band, thus realizing a high-isolation MIMO architecture.

[0044] Furthermore, the ground plane employs a non-complete defect structure. By optimizing the etching shape and position, the antenna impedance bandwidth is effectively extended, achieving dual broadband coverage and improving high-frequency radiation efficiency. The invention's unique compact conformal structure design implements all functional structures on a single-layer board, eliminating multi-layer stacking and external circuitry. It features low profile, lightweight design, and easy conformal integration, making it suitable for integration into high-speed moving platforms.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultra-wideband MIMO antenna, comprising a dielectric substrate (2), characterized in that, It also includes four antenna units, which are centrally symmetrically distributed on the front side of the dielectric substrate (2). Each antenna unit includes a radiating patch (1) and a microstrip feed line (3) connected to the radiating patch (1). The antenna unit further includes a DGS ground plane (5), which is disposed on the back side of the dielectric substrate (2); Each of the radiating patches (1) is etched with trapezoidal slots and curved arch slots for achieving notch filtering and broadband coverage. The DGS ground plane (5) is etched with an I-shaped groove (4); Furthermore, a figure-eight stub (6) connects the DGS ground plane (5) regions corresponding to the two antenna elements located diagonally.

2. The ultra-wideband MIMO antenna according to claim 1, characterized in that, The antenna operates over two consecutive widebands: 5.2GHz-13.2GHz and 14.5GHz-16.3GHz, and exhibits notch characteristics in the 13.2GHz-14.5GHz band.

3. The ultra-wideband MIMO antenna according to claim 1, characterized in that, The width of the trapezoidal groove gradually increases from 0.3 mm to 0.9 mm.

4. The ultra-wideband MIMO antenna according to claim 1, characterized in that, The microstrip feed line (3) has a trapezoidal structure.

5. The ultra-wideband MIMO antenna according to claim 1, characterized in that, The figure-eight branches (6) consist of four sections, symmetrically arranged between the DGS ground plane (5) areas corresponding to each pair of antenna elements located at diagonal positions.

6. The ultra-wideband MIMO antenna according to any one of claims 1-5, characterized in that, The dielectric substrate (2) is made of FR4 material.

7. The ultra-wideband MIMO antenna according to claim 6, characterized in that, The overall dimensions of the dielectric substrate (2) are 36mm × 36mm × 1.635mm.

8. The ultra-wideband MIMO antenna according to claim 6, characterized in that, The FR4 material has a dielectric constant of 4.4 and a thickness of 1.6 mm.

9. The ultra-wideband MIMO antenna according to any one of claims 1-5, characterized in that, The isolation parameter S between the antenna elements 21 S 31 S 41 The value is above 15dB in the 5-16GHz frequency band.

10. The ultra-wideband MIMO antenna according to any one of claims 1-5, characterized in that, The notch has a depth exceeding -5dB in the 13.2-14.5GHz band.

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