Ultra-wideband low-profile tight coupling antenna unit and antenna array

Abstract

The invention provides a tightly-coupled low-profile ultra-wideband antenna unit and an antenna array, and relates to the technical field of tightly-coupled ultra-wideband antennas. The antenna unit comprises a high-dielectric-constant wide-angle impedance matching layer, a low-dielectric-constant wide-angle matching layer, a dual-polarization dipole antenna, a grounding probe, a concave patch, a feed structure, a third-layer dielectric plate, a fourth-layer dielectric plate, a metal floor and a prepreg. According to the antenna array, the double-frequency impedance bandwidth is realized in an X-ku frequency band, the unit spacing is 9.4 mm, the profile height is 3.9 mm, and the design requirement of a low profile is met; two quasi-coaxial structures are adopted to feed vertical polarization and horizontal polarization of the antenna, the feed structure is simple, and the processing difficulty is reduced; the four corners of the antenna unit are designed to be of a hollow structure, and the lightweight design of the antenna array is achieved. The problems that an existing ultra-wideband antenna is complex in structure, high in profile, heavy in weight, high in cost and difficult to meet the design requirements of low profile and light weight of the ultra-wideband antenna are solved.

Description

Technical Field

[0001] This document relates to the field of tightly coupled ultra-wideband antenna technology, and in particular to a tightly coupled low-profile ultra-wideband antenna element and antenna array. Background Technology

[0002] Ultra-wideband antennas carry a larger signal capacity than traditional communication methods, and have strong anti-interference, anti-multipath, and penetration capabilities. They can not only transmit and receive broadband or relatively discrete signals with a single array, but also achieve common aperture, saving costs between antennas and systems.

[0003] Traditional broadband antennas generally do not consider the mutual coupling effect between antenna elements. The element spacing design needs to simultaneously suppress grating lobes and meet wide-angle impedance matching. After arraying, the mutual coupling effect between elements will cause impedance mismatch in the array antenna, requiring "decoupling" measures. For example, the impedance matching bandwidth of a commonly used ultra-wideband Vivaldi antenna is positively correlated with its height, making it difficult to simultaneously meet the requirements of ultra-wideband, wide scanning angle, and small size. Generally, tightly coupled antennas use strong capacitive coupling between adjacent dipole elements to offset the inductive effect of the metal ground plane in the low-frequency band, greatly widening the impedance bandwidth of the antenna. Vertical dipole tightly coupled antennas use a "Madrick balun" feeding structure to achieve broadband impedance matching in order to achieve dual polarization design. Its profile height is lower than that of the Vivaldi antenna, but it still has the characteristics of high profile and complex structure. At present, most ultra-wideband antennas use Vivaldi antennas because its bandwidth is positively correlated with its profile, and the mutual coupling effect between elements in the array needs to be considered to cause impedance mismatch in the array antenna, requiring decoupling, making it difficult to meet the low profile and lightweight design requirements of ultra-wideband antennas.

[0004] Therefore, there is an urgent need for an ultra-wideband antenna array to solve the problems of complex structure, high profile, heavy weight, and high cost of current ultra-wideband antennas, which make it difficult to meet the requirements of low profile and lightweight design of ultra-wideband antennas. Summary of the Invention

[0005] This specification provides a tightly coupled, low-profile ultra-wideband antenna element and antenna array to address the current challenges of complex structures, high profiles, heavy weights, and high costs associated with ultra-wideband antennas, which make it difficult to meet the requirements for low-profile and lightweight design of ultra-wideband antennas.

[0006] In one aspect, this specification provides a tightly coupled low-profile ultra-wideband antenna element, characterized in that it comprises: a high dielectric constant wide-angle impedance matching layer, a low dielectric constant wide-angle matching layer, a dual-polarized dipole antenna, a grounding probe, a concave patch, a feeding structure, a third dielectric substrate, a fourth dielectric substrate, a metal ground plane, and a prepreg.

[0007] Among them, the dielectric constant of the high dielectric constant wide-angle impedance matching layer is between 10 and 11;

[0008] The dielectric constant of the low dielectric constant wide-angle matching layer is between 2 and 3;

[0009] The dual-polarized dipole antenna is the basic unit form of a tightly coupled antenna, used to radiate electromagnetic waves;

[0010] Grounding probes are used to interconnect the dipole antenna with the reference ground to form an electric field loop;

[0011] The concave patch forms a coupling capacitor with the concave patch of the adjacent antenna element to cancel the inductive energy reflected by the metal ground plane;

[0012] The power supply structure uses coaxial power supply to reduce the complexity of the structure.

[0013] The third and fourth dielectric substrates are used to etch metal patterns and support the entire antenna.

[0014] The metal ground plane is used as the antenna's reference ground and welding surface;

[0015] Prepreg is used to achieve adhesive interconnection between all media plates.

[0016] Secondly, this specification provides a tightly coupled low-profile ultra-wideband antenna array, characterized in that it includes a plurality of tightly coupled low-profile ultra-wideband antenna elements; wherein the spacing between the antenna elements is 9.4 mm;

[0017] After the antenna unit is pressed together, four fan-shaped bodies of the same size are drilled out at the four corners. After being arrayed with three adjacent antenna units, they form a complete air cylinder, creating a hollow structure. After being assembled into an array, they form an air cylinder with a diameter of D4.

[0018] Thirdly, this specification provides a communication device including a plurality of tightly coupled low-profile ultra-wideband antenna elements, or including a tightly coupled low-profile ultra-wideband antenna array.

[0019] The beneficial effects of this invention are as follows:

[0020] This specification provides a tightly coupled, low-profile ultra-wideband antenna element and array. The antenna element includes a high-dielectric-constant wide-angle impedance matching layer, a low-dielectric-constant wide-angle matching layer, a dual-polarized dipole antenna, a grounding probe, a concave patch, a feeding structure, a third dielectric substrate, a fourth dielectric substrate, a metal ground plane, and a prepreg. Two quasi-coaxial structures are used to feed the antenna for both vertical and horizontal polarization, simplifying the feeding structure and reducing fabrication difficulty. The antenna element features hollowed-out structures at its four corners, enabling a lightweight antenna array design. This antenna array achieves a 2-harmonic impedance bandwidth in the X-Ku band, with an element spacing of 9.4 mm and a profile height of 3.9 mm, meeting the low-profile design requirements. This solves the problem of current ultra-wideband antennas being complex, high-profile, heavy, and costly, making it difficult to meet the low-profile, lightweight design requirements of ultra-wideband antennas. This antenna array features a simple structure, low profile, lightweight design, and low cost, making it more suitable for miniaturized platforms. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this specification and form part of this specification, illustrate exemplary embodiments and are used to explain this specification, but do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 This is a schematic diagram of an ultra-wideband low-profile tightly coupled antenna element provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of an ultra-wideband low-profile tightly coupled antenna array provided in an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of a dual-polarized dipole antenna provided in this invention embodiment;

[0025] Figure 4 A schematic diagram of the power supply structure and grounding probe location provided in the embodiments of the present invention;

[0026] Figure 5 A schematic diagram of the concave patch provided in the embodiment of the present invention;

[0027] Figure 6 A schematic diagram of standing wave simulation provided by the present invention;

[0028] Figure 7 A schematic diagram of dual-polarization two-port isolation provided in the embodiments of the present invention;

[0029] Figure 8 A schematic diagram of wide-angle scanning of an ultra-wideband low-profile tightly coupled antenna array provided in this invention example.

[0030] Figure label:

[0031] 1. High dielectric constant wide-angle impedance matching layer; 2. Low dielectric constant wide-angle matching layer; 3. Dual-polarized dipole antenna; 4. Grounding probe; 5. Concave patch; 6. Feed structure; 7. Third dielectric substrate; 8. Fourth dielectric substrate; 9. Metal ground plane; 10. Prepreg. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this specification clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments in this specification, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this document.

[0033] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings. Specific Implementation Example 1:

[0035] This embodiment provides a tightly coupled, low-profile, ultra-wideband antenna element. See [link / reference] Figures 1-8 ;

[0036] It should be noted that the element size of tightly coupled antennas is currently negatively correlated with impedance bandwidth. However, due to the limitations of TR chip power design and soldering process, the element spacing of the antenna needs to be ≥8.5mm, which contradicts the general design concept of tightly coupled antennas. This embodiment proposes an ultra-wideband low-profile tightly coupled antenna array with an element spacing of 9.4mm, achieving a 2-harmonic impedance bandwidth in the X-ku band. At the same time, it solves the problems of complex structure, high profile, heavy weight, and high cost of existing ultra-wideband antennas, and has more applicable scenarios and great application and promotion potential.

[0037] The tightly coupled low-profile ultra-wideband antenna element provided in this embodiment, such as Figure 1 As shown, the specific structure includes the following: a high dielectric constant wide-angle impedance matching layer 1, a low dielectric constant wide-angle matching layer 2, a dual-polarized dipole antenna 3, a grounding probe 4, a concave patch 5, a feeding structure 6, a third dielectric substrate 7, a fourth dielectric substrate 8, a metal ground plane 9, and a prepreg 10.

[0038] Among them, the dielectric constant of the high dielectric constant wide-angle impedance matching layer 1 is between 10 and 11;

[0039] The dielectric constant of the low dielectric constant wide-angle matching layer 2 is between 2 and 3;

[0040] The dual-polarized dipole antenna 3 is the basic unit form for realizing a tightly coupled antenna, used to radiate electromagnetic waves;

[0041] Grounding probe 4 is used to interconnect the dipole antenna with the reference ground to form an electric field loop;

[0042] The concave patch 5 forms a coupling capacitor with the concave patch of the adjacent antenna element to cancel the inductive energy reflected by the metal ground plane (9);

[0043] The power supply structure 6 adopts coaxial power supply to reduce the complexity of the structure;

[0044] The third dielectric substrate 7 and the fourth dielectric substrate 8 are used to etch metal patterns and support the entire antenna.

[0045] Metal ground plane 9 serves as the reference ground and welding surface for the antenna;

[0046] Prepreg 10 is used to achieve adhesive interconnection between all media plates.

[0047] Furthermore, the following is a detailed description of each component of the antenna element:

[0048] Specifically, the ultra-wideband low-profile tightly coupled antenna unit is made of four layers of dielectric substrates laminated together and welded to a metal ground plane. The four dielectric substrates include a high dielectric constant wide-angle matching layer 1, a low dielectric constant wide-angle matching layer 2, a third dielectric substrate 7, and a fourth dielectric substrate 8.

[0049] Specifically, the high dielectric constant wide-angle matching layer 1 and the low dielectric constant wide-angle matching layer 2 of the antenna element have the same thickness, both h1 = 0.508 mm; the thickness of the third dielectric substrate 7 is h2 = 1.778 mm, the thickness of the fourth dielectric substrate 8 is h3 = 0.762 mm, the thickness of the metal ground plate 9 is h4 = 0.035 mm, the thickness of the prepreg 10 is h_pp = 0.119 mm, and the profile height of the antenna element is 3.9 mm.

[0050] Furthermore, such as Figure 3 As shown, the dual-polarized dipole antenna 3 is printed on the upper surface of the third dielectric substrate 7. The polarization dimensions are exactly the same and they are arranged symmetrically. The different polarized dipole antennas are distributed perpendicularly to each other. A slot is cut in the 45° direction with a slot width of w = 0.1 mm.

[0051] Furthermore, such as Figure 4 As shown, there are a total of 6 grounding probes 4. Four of them have the same diameter, denoted as d1. These four grounding probes 4 with the same diameter are distributed in a centrally symmetrical manner, with a distance of L1 from the origin. The remaining two grounding probes 4 have the same diameter, d2, and a distance of L2 from the origin.

[0052] The grounding probe 4 connects the dual-polarized dipole antenna 3 to the metal ground plane 9, forming a current loop.

[0053] L1 and d1 affect the port isolation and high-frequency cutoff frequency of the two polarizations, while L2 and d2 affect the low-frequency cutoff frequency.

[0054] It should be noted that L1 and d1 influence each other, and L2 and d2 influence each other.

[0055] Furthermore, such as Figure 4 As shown, the feed structure 6 consists of two probes, each with a diameter of d3, using a quasi-coaxial feeding method to power the antenna's vertical and horizontal polarization, respectively. The feed structure 6 connects the feed port to the dual-polarized dipole antenna 3, and its position is axially symmetrical with the two grounding probes with a diameter of d2. The feed structure is simple, reducing the difficulty of fabrication.

[0056] Furthermore, such as Figure 5 As shown, the concave patch 5 is a metal pattern. Two layers of concave patches form a group, and there are four groups in total. Two groups of concave patches are connected to two grounding probes 4 with a diameter of d2, and the other two groups of concave patches are connected to the power supply structure 6.

[0057] Among them, a group of concave patches are attached to the lower surface of the third layer dielectric substrate 7 and the upper surface of the fourth layer dielectric 8, respectively, with a vertical spacing of one layer of prepreg thickness h_pp; the four groups of concave patches 5 are distributed in a centrally symmetrical manner.

[0058] The concave patch 5 is at a height of h3 from the metal floor 9. The low-frequency frequency of the operating bandwidth is adjusted, and a coupling capacitor is formed to counteract the inductive energy reflected by the metal floor.

[0059] Furthermore, this embodiment also provides a tightly coupled low-profile ultrawideband antenna array, see [link to previous document]. Figure 2 It includes multiple tightly coupled low-profile ultrawideband antenna elements; the spacing between the antenna elements is 9.4 mm; that is, the spacing between the center points of the antenna array elements is 9.4 mm.

[0060] After the antenna elements are pressed together, four identical sector-shaped parts are drilled out at the four corners. These are then combined with three adjacent antenna elements to form a complete air cylinder, creating a hollow structure. When assembled into an array, this forms an air cylinder with a diameter of D4. This achieves a lightweight antenna array design.

[0061] It should be noted that, generally speaking, the smaller the antenna spacing, the better the effect, and the larger the antenna spacing, the worse the effect. In this embodiment, the spacing between antenna elements is 9.4mm, achieving a 2-fold impedance bandwidth in the X-ku band.

[0062] Furthermore, the ultra-wideband low-profile tightly coupled antenna provided in this embodiment has a standing wave ratio of <3 within the 2-octave impedance bandwidth, which meets the wideband design requirements.

[0063] The ultra-wideband low-profile tightly coupled antenna has a port isolation of <-17 within the 2-harmonic impedance bandwidth, which meets the dual-polarization port isolation requirements.

[0064] Wide-angle scanning simulation of an ultra-wideband low-profile tightly coupled antenna array showed that the gain decreased by 2dB compared to the normal direction when scanning to ±60°, indicating good performance after antenna arraying.

[0065] In summary, the antenna element in this embodiment includes a high dielectric constant wide-angle impedance matching layer, a low dielectric constant wide-angle matching layer, a dual-polarized dipole antenna, a grounding probe, a concave patch, a feeding structure, a third dielectric substrate, a fourth dielectric substrate, a metal ground plane, and a prepreg. Two coaxial structures are used to feed the antenna for both vertical and horizontal polarization, resulting in a simple feeding structure and reduced fabrication difficulty. The antenna element features hollowed-out structures at its four corners, achieving a lightweight antenna array design. This antenna array achieves a 2-harmonic impedance bandwidth in the X-Ku band, with an element spacing of 9.4 mm and a profile height of 3.9 mm, meeting the low-profile design requirements. This solves the problem of current ultra-wideband antennas being complex in structure, high in profile, heavy in weight, and costly, making it difficult to meet the low-profile, lightweight design requirements of ultra-wideband antennas. This antenna array features a simple structure, low profile, lightweight design, and low cost, making it more suitable for miniaturized platforms. Specific Implementation Example 2:

[0067] This embodiment provides an ultra-wideband low-profile tightly coupled antenna element;

[0068] Specifically, the ultra-wideband low-profile tightly coupled antenna element is composed of four layers of dielectric substrate laminated together and welded to a metal ground plane.

[0069] The four dielectric substrates include a high dielectric constant wide-angle matching layer 1, a low dielectric constant wide-angle matching layer 2, a third dielectric substrate 7, and a fourth dielectric substrate 8.

[0070] The thickness of the high dielectric constant wide-angle matching layer 1 and the low dielectric constant wide-angle matching layer 2 is h1 = 0.508 mm, the thickness of the third dielectric layer 7 is h2 = 1.778 mm, and the thickness of the fourth dielectric layer 7 is h3 = 0.762 mm.

[0071] The prepreg thickness h_pp = 0.119 mm. Four identical fan-shaped bodies are drilled out at the four corners of the four-layer dielectric to form a hollow structure. After being assembled into an array, they form an air cylinder with a diameter of 8 mm. The spacing between the antenna elements is 9.4 mm.

[0072] like Figure 1 As shown, this embodiment also provides an antenna array of 6*7 with dimensions of 56.4mm×65.8mm×3.9mm;

[0073] Furthermore, the dual-polarized dipole antenna 3 is located on the upper surface of the third dielectric substrate. The different polarized dipole antennas are distributed perpendicularly to each other, and a slot is cut in the 45° direction with a slot width w = 0.1 mm. The two polarizations are exactly the same size and are arranged symmetrically.

[0074] There are 6 grounding probes 4. The 4 grounding probes with a diameter d1 = 0.4 mm are symmetrical about the origin and are spaced L1 = 1.1 mm from the origin. The 2 grounding probes with a diameter d2 = 1 mm are spaced L2 = 2.8 mm from the origin. The dual-polarized dipole antenna 3 is connected to the metal ground plate 9 to form a current loop.

[0075] The concave patches 5 are located on the lower surface of the third dielectric substrate 7 and the upper surface of the fourth dielectric substrate 8, with dimensions of 1.7mm × 1mm. There are four groups of these concave patches, arranged in a centrally symmetrical manner. The vertical distance between each group of concave patches is equal to the thickness of one layer of laminated PP, h_pp = 0.119mm. Two groups of concave patches are connected to two grounding probes 4 with a diameter of d2, and the other two groups are connected to the feed structure 6. The distance between each group of concave patches and the concave patches of the adjacent tightly coupled antenna element is 0.2mm, and the height from the metal ground plane 9 is h3. The purpose of this is to adjust the low-frequency range of the operating bandwidth and to form a coupling capacitance to cancel the inductive energy reflected by the metal ground plane.

[0076] The feeding structure 6 uses two coaxial feeds with a diameter d3 = 0.4 mm. The feed port is connected to the dual-polarized dipole antenna. Its position is axially symmetrical with the grounding probe with a diameter d2, which reduces the complexity of the structure and lowers the profile height of the antenna.

[0077] like Figure 4 As shown, this embodiment provides the relative positions of the feeding structure 6 and the dual-polarized dipole antenna 3, with a diameter d3 = 0.4 mm and a distance L2 = 2.8 mm from the antenna origin. The relative positions of the grounding probe 4 and the dual-polarized dipole antenna 3 are also shown. Four probes with a diameter d1 = 0.4 mm are positioned at a distance L1 = 1.1 mm from the origin, and two probes with a diameter d2 = 1 mm are positioned at a distance L2 = 2.8 mm from the origin.

[0078] Furthermore, this embodiment also provides a simulation experiment, the results of which can be found in [reference needed]. Figure 6 , Figure 7 , Figure 8 From this, we can see that:

[0079] The ultra-wideband low-profile tightly coupled antenna provided in this embodiment has a standing wave ratio of <3 in the 2-harmonic impedance bandwidth, which meets the wideband design requirements.

[0080] The ultra-wideband low-profile tightly coupled antenna has a port isolation of <-17 within the 2-harmonic impedance bandwidth, which meets the dual-polarization port isolation requirements.

[0081] Wide-angle scanning simulation of an ultra-wideband low-profile tightly coupled antenna array showed that the gain decreased by 2dB compared to the normal direction when scanning to ±60°, indicating good performance after antenna arraying.

[0082] In summary, the antenna element in this embodiment includes a high dielectric constant wide-angle impedance matching layer, a low dielectric constant wide-angle matching layer, a dual-polarized dipole antenna, a grounding probe, a concave patch, a feeding structure, a third dielectric substrate, a fourth dielectric substrate, a metal ground plane, and a prepreg. Two coaxial structures are used to feed the antenna for both vertical and horizontal polarization, resulting in a simple feeding structure and reduced fabrication difficulty. The antenna element features hollowed-out structures at its four corners, achieving a lightweight antenna array design. This antenna array achieves a 2-harmonic impedance bandwidth in the X-Ku band, with an element spacing of 9.4 mm and a profile height of 3.9 mm, meeting the low-profile design requirements. This solves the problem of current ultra-wideband antennas being complex in structure, high in profile, heavy in weight, and costly, making it difficult to meet the low-profile, lightweight design requirements of ultra-wideband antennas. This antenna array features a simple structure, low profile, lightweight design, and low cost, making it more suitable for miniaturized platforms. Specific Implementation Example 3:

[0084] This embodiment also provides a communication device, including multiple tightly coupled low-profile ultra-wideband antenna elements, or including a tightly coupled low-profile ultra-wideband antenna array.

[0085] The above description is merely a preferred embodiment of this specification and is not intended to limit this specification. Various modifications and variations can be made to this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of protection of this specification.

Claims

1. A tightly coupled, low-profile, ultra-wideband antenna element, characterized in that, include: High dielectric constant wide-angle impedance matching layer (1), low dielectric constant wide-angle matching layer (2), dual-polarized dipole antenna (3), grounding probe (4), concave patch (5), feed structure (6), third dielectric substrate (7), fourth dielectric substrate (8), metal ground plane (9) and prepreg (10); Among them, the dielectric constant of the high dielectric constant wide-angle impedance matching layer (1) is between 10 and 11; The dielectric constant of the low dielectric constant wide-angle matching layer (2) is between 2 and 3; The dual-polarized dipole antenna (3) is the basic unit form of a tightly coupled antenna, used to radiate electromagnetic waves; Grounding probe (4) is used to interconnect the dipole antenna with the reference ground to form an electric field loop; The concave patch (5) forms a coupling capacitor with the concave patch of the adjacent antenna element to cancel the inductive energy reflected by the metal ground plane (9); The power supply structure (6) adopts coaxial power supply to reduce the complexity of the structure; The third dielectric substrate (7) and the fourth dielectric substrate (8) are used to etch metal patterns to support the entire antenna. The metal ground plane (9) is used as the reference ground and welding surface for the antenna; Prepreg (10) is used to achieve adhesive interconnection between all media plates.

2. The tightly coupled low-profile ultra-wideband antenna element according to claim 1, characterized in that, The dual-polarized dipole antenna (3) is printed on the upper surface of the third dielectric substrate (7). The polarization dimensions are exactly the same and are arranged symmetrically. The different polarized dipole antennas are distributed perpendicularly to each other. A slot is cut in the 45° direction with a slot width of w = 0.1 mm.

3. The tightly coupled low-profile ultra-wideband antenna element according to claim 2, characterized in that, There are 6 grounding probes (4). Four of them have the same diameter, denoted as d1. These four grounding probes (4) with the same diameter are distributed in a centrally symmetrical manner, with a distance of L1 from the origin. The other two grounding probes (4) have the same diameter, d2, with a distance of L2 from the origin. The grounding probe (4) connects the dual-polarized dipole antenna (3) to the metal ground plane (9) to form a current loop.

4. The tightly coupled low-profile ultra-wideband antenna element according to claim 3, characterized in that, There are two feeding structures (6), both with a diameter of d3, and they adopt a coaxial feeding method to supply power to the antenna vertically polarized and horizontally polarized, respectively. The feeding structure (6) connects the feeding port to the dual-polarized dipole antenna (3). The position of the feeding structure (6) is axially symmetrical with the two grounding probes with a diameter of d2.

5. The tightly coupled low-profile ultra-wideband antenna element according to claim 4, characterized in that, The concave patch (5) is a metal pattern. Two layers of concave patches are a group, and there are four groups in total. Two groups of concave patches are connected to two grounding probes (4) with a diameter of d2, and the other two groups of concave patches are connected to the power supply structure (6). Among them, a group of concave patches are attached to the lower surface of the third layer of dielectric substrate (7) and the upper surface of the fourth layer of dielectric substrate (8), with a vertical spacing of one layer of prepreg thickness h_pp; the four groups of concave patches (5) are distributed in a centrally symmetrical manner. The concave patch (5) is at a height of h3 from the metal floor (9). The low frequency of the working bandwidth is adjusted, and a coupling capacitor is formed to counteract the inductive energy reflected by the metal floor.

6. The tightly coupled low-profile ultra-wideband antenna element according to claim 5, characterized in that, The high dielectric constant wide-angle matching layer (1) and the low dielectric constant wide-angle matching layer (2) have the same thickness, h1 = 0.508 mm; the thickness of the third dielectric substrate (7) is h2 = 1.778 mm, the thickness of the fourth dielectric substrate (8) is h3 = 0.762 mm, the thickness of the metal ground plate (9) is h4 = 0.035 mm, the thickness of the prepreg (10) is h_pp = 0.119 mm, and the antenna element profile height is 3.9 mm.

7. A tightly coupled, low-profile, ultra-wideband antenna array, characterized in that, It includes several tightly coupled low-profile ultrawideband antenna elements as described in any one of claims 1-6; wherein the spacing between the antenna elements is 9.4 mm; After the antenna unit is pressed together, four fan-shaped bodies of the same size are drilled out at the four corners. After being arrayed with three adjacent antenna units, they form a complete air cylinder, creating a hollow structure. After being assembled into an array, they form an air cylinder with a diameter of D4.

8. The tightly coupled low-profile ultrawideband antenna array according to claim 1, characterized in that, The standing wave ratio of the ultra-wideband low-profile tightly coupled antenna is <3 within the 2-harmonic impedance bandwidth.

9. The tightly coupled low-profile ultra-wideband antenna array according to claim 1, characterized in that, The port isolation of the ultra-wideband low-profile tightly coupled antenna is <-17 within the 2-harmonic impedance bandwidth.

10. A communication device, characterized in that, It includes any of the tightly coupled low-profile ultra-wideband antenna elements as described in any one of claims 1-6, or includes the tightly coupled low-profile ultra-wideband antenna array as described in claim 7.

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