An ultra-low profile dual-polarized array based on tight coupling to realize ultra-wideband angular scanning

Abstract

An ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning includes N*N periodically arranged dual-polarization units, where N≥2. Each dual-polarization unit includes a ground plane, and a feed dielectric substrate is vertically placed above the ground plane. Curvature-gradient baluns and wedge dipoles are printed on both sides of the feed dielectric substrate. The wedge dipoles are located above the curvature-gradient baluns, with the upper port of the curvature-gradient balun connected to the wedge dipole, and the lower port of the curvature-gradient balun connected to the ground plane. A periodic surface is provided above the wedge dipole. First and second short-circuit posts are respectively attached to the two edges of the feed dielectric substrate, located on opposite sides of the curvature-gradient balun. Asymmetric stubs are printed on the feed dielectric substrate behind the first short-circuit post, and the first short-circuit post is connected to the asymmetric stubs. This invention saves antenna design space and improves antenna performance.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, and specifically relates to an ultra-low profile dual-polarization array that achieves ultra-wide bandwidth angle scanning based on tight coupling. Background Technology

[0002] With the increasing maturity of wireless communication technology, ultra-wideband, wide-angle scanning, and multi-polarization technologies have become the focus of antenna technology research. Dual-polarized antennas can receive electromagnetic waves from different directions within the same frequency band, such as vertical and horizontal polarization, enabling frequency division multiplexing and expanding the capacity of communication systems. Tight-coupled antenna technology, due to its ultra-wideband and miniaturization characteristics, is gaining increasing attention. Therefore, combining tight-coupled antennas with dual-polarization technology to form a broadband dual-polarized tight-coupled wide-angle scanning antenna is of significant developmental importance. Currently, tight-coupled phased array antennas achieve wide-angle scanning by loading a wide-angle matching layer on top of the antenna; this is typically a high-dielectric-constant dielectric layer or a periodic frequency-selective surface, which increases the overall array height. When linearly polarized antenna arrays achieve large-angle scanning in the H-plane, their port input impedance undergoes drastic changes and is difficult to match using impedance transformers.

[0003] As modern communication devices become increasingly smaller, the demands on antennas for miniaturized integration in devices such as drones, automobiles, and small satellites are rising. Traditional broadband antennas, including Vivaldi antennas, planar monopole antennas, and microstrip patch linear arrays, struggle to simultaneously achieve broadband, low-profile, dual-polarized, wide-angle scanning characteristics. Compared to traditional ultra-wideband phased array antennas, tightly coupled phased array antennas can simultaneously achieve ultra-wideband and ultra-wide-angle scanning characteristics, while also better meeting the low-profile requirements.

[0004] Patent application CN114421148A discloses "a dual-polarized ultra-wide bandwidth tightly coupled array antenna", which provides a ±45° dual-polarized tightly coupled antenna array based on a butterfly dipole, loaded with a resistive frequency selective surface and a periodic metal cladding, achieving a 9th harmonic operating frequency band and having a ±60° scanning capability in the D-plane.

[0005] In ultra-wideband wide-angle scanning antenna design, ultra-wideband impedance matching during side-firing is typically achieved by loading an ultra-wideband impedance transformer, followed by loading a wide-angle matching layer above the antenna to improve impedance characteristics and meet the wide-angle scanning requirements. Wideband impedance transformers are generally based on microstrip baluns to transform the impedance of tightly coupled antennas from 100Ω-200Ω to 50Ω. However, in the aforementioned existing technologies, it is difficult for the impedance transformers of tightly coupled antenna arrays to simultaneously achieve ultra-wideband, small size, low profile, and simple design. Commonly used wide-angle scanning matching layers consist of a single or multiple dielectric block matching layer and a metal cladding loaded above the antenna, effectively improving the active standing wave characteristics during wide-angle scanning, but significantly increasing the antenna profile height. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention aims to provide an ultra-low profile dual-polarized array that achieves ultra-wide bandwidth angle scanning based on tight coupling. By loading a periodic surface, the scanning characteristics of the array can be improved, achieving the technical effect of wide-angle scanning in the E-plane and H-plane. By loading a composite resistive structure and asymmetric stubs, the active VSWR can be improved while widening the bandwidth, saving antenna design space and improving antenna performance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An ultra-low profile dual-polarization array for ultra-wide bandwidth scanning based on tight coupling includes N*N periodically arranged dual-polarization units, where N≥2. Each dual-polarization unit includes a ground plane 80, and a feed dielectric substrate 70 is vertically placed above the ground plane 80. Curvature-gradient baluns 30 and wedge dipoles 20 are printed on both sides of the feed dielectric substrate 70. The wedge dipoles 20 are located above the curvature-gradient baluns 30, and the upper port of the curvature-gradient baluns 30 is connected to the wedge dipoles 20. Next, the lower port of the curvature gradient balun 30 is connected to the ground plane 80. A periodic surface 10 is provided above the wedge dipole 20. The two sides of the feed dielectric substrate 70 are respectively attached with a first short-circuit post 61 and a second short-circuit post 62, and the first short-circuit post 61 and the second short-circuit post 62 are located on both sides of the curvature gradient balun 30. An asymmetric branch 40 is printed on the feed dielectric substrate 70 on the back of the first short-circuit post 61. The first short-circuit post 61 is connected to the asymmetric branch 40.

[0009] The floor 80 includes a bottom dielectric substrate 82 placed horizontally at the bottom and a coaxial connector 81 located on the bottom dielectric substrate 82, the coaxial connector 81 being connected to the lower port of the curvature gradient balun 30.

[0010] The asymmetric branch 40 includes a vertical metal extension patch 42 printed on the edge of the feed dielectric substrate 70 and a horizontal metal extension patch 43 etched on the ground plane 80. The vertical metal extension patch 42 is connected to the ground side of the curvature gradient balun 30, the horizontal metal extension patch 43 is connected to the second short-circuit post 62, and the vertical metal extension patch 42 is connected to the first short-circuit post 61 through the metal post 41.

[0011] Both the vertical metal extension patch 42 and the horizontal metal extension patch 43 are loaded between the wedge dipole 20 and the floor 80.

[0012] A composite resistive structure 50 is horizontally disposed between the wedge dipole 20 and the ground plane 80. The composite resistive structure 50 includes an upper resistive surface structure 51 and a symmetrical metal grid structure 52. The upper resistive surface structure 51 is located above the symmetrical metal grid structure 52.

[0013] The first short-circuit post 61 is composed of a first rectangular metal strip 63 and a first resistor 64 thereon; the second short-circuit post 62 is composed of a second rectangular metal strip 65 and a second resistor 66 thereon.

[0014] The periodic surface 10 includes a first dielectric substrate 12, on which a cross-shaped metal patch 11 is attached. The cross rectangle of a single unit of the cross-shaped metal patch 11 has dimensions of (0.3mm-0.4mm)*(1.6mm-2mm).

[0015] The upper resistive surface structure 51 includes a second dielectric substrate 54, on which a resistive surface 53 is printed; the symmetrical metal grid structure 52 is composed of orthogonal rectangular metal strips, including a symmetrical metal grid patch 55 and a third dielectric substrate 56.

[0016] The overall height of the upper resistive surface structure 51 is 10mm-11mm; the cross rectangle of the lower metal grid structure 52 has a size of (0.8mm-1.2mm)*19.09mm and an overall height of 8.5mm-9.5mm.

[0017] The lateral side length of the dual-polarization unit is (19.00mm-19.55mm)*(19.00mm-19.55mm), and the overall profile height of the antenna is 42.0mm-43.0mm.

[0018] The bottom side of the gradually curvature balun 30 has a width of 3.00mm-3.50mm and a curvature of 1 on one side, and a width of 2.00mm-2.30mm and a curvature of 108 on the other side. The feed line height is 23.5mm-24.5mm. The wedge dipole 20 has a height of 12.4mm-12.8mm, an upper width of 5.8mm-6.2mm, and a lower width of 10.2mm-11.2mm.

[0019] The metal column 41 in the asymmetric branch 40 has a width of 1.4mm-1.6mm, the vertical metal extension patch 42 has a height of 15mm-16mm and a width of 0.3mm-0.5mm, and the horizontal metal extension patch 43 has a length of 6mm-7mm and a width of 0.3mm-0.5mm.

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

[0021] 1. The periodic surface 10 loaded above the antenna in this invention has a relatively thin thickness, and the cross-shaped metal patch 11 is attached to a single layer of thin dielectric F4b. Compared with the traditional method of loading a single or multiple dielectric block matching layer and metal cladding, it does not significantly increase the overall profile height of the antenna array.

[0022] 2. The periodic surface 10 loaded in this invention is mainly used to match the impedance mismatch during H-plane scanning, and also has a certain improvement effect on the E-plane; it can solve the impedance mismatch of the antenna during E-plane and H-plane scanning, and effectively improve the active VSWR of the antenna array during large-angle scanning.

[0023] 3. The composite resistive structure 50 loaded in this invention is located between the wedge dipole 20 and the ground plane 80. While achieving the goal of improving the performance of the antenna's E-plane and H-plane and widening the antenna's operating frequency band, it makes reasonable use of the antenna's spatial structure and will not affect the antenna's profile height.

[0024] 4. The asymmetric branch 40 of the present invention has a simple topology, consisting only of a vertical rectangular metal extension patch 42, a horizontal rectangular metal extension patch 43 and a metal pillar 41, and is etched on the surface of the feed dielectric substrate 70, which is easy to process and does not affect the size of the antenna.

[0025] In summary, this invention solves the problem of difficult matching in wide-angle scanning of the H-plane of current broadband tightly coupled arrays by employing a periodic surface 10, an asymmetric stub 40, and a composite resistive structure 50. Since the periodic surface 10 is relatively thin and the asymmetric stub 40 and the composite resistive structure 50 are loaded between the wedge dipole 20 and the ground plane 80, the antenna space is rationally utilized. Therefore, the overall antenna profile of this invention is lower and the antenna's operating bandwidth is significantly broadened. Attached Figure Description

[0026] Figure 1 This is an overall structural diagram of the antenna of the present invention.

[0027] Figure 2 This is a diagram showing the positional relationship of the asymmetric stub 40 of the antenna of the present invention.

[0028] Figure 3 This is a diagram showing the positional relationship between the asymmetric branch 40, the first short-circuit post 61, and the second short-circuit post 62 of the present invention.

[0029] Figure 4 This is a schematic diagram of the structure of the periodic surface 10 of the present invention.

[0030] Figure 5 is a schematic diagram of the composite resistive structure 50 of the present invention, wherein Figure 5(a) is a schematic diagram of the upper resistive surface structure 51 of the present invention, and Figure 5(b) is a schematic diagram of the symmetrical metal grid structure 52 of the present invention.

[0031] Figure 6 shows the active standing wave curves of the present invention; wherein, Figure 6(a) is the active standing wave curve of the E-plane of the present invention without the loading of a periodic surface, and Figure 6(b) is the active standing wave curve of the H-plane of the present invention without the loading of a periodic surface.

[0032] Figure 7 shows the active standing wave curves of the present invention; wherein, Figure 7(a) is the E-plane active standing wave curve of the present invention without the addition of asymmetric branches, and Figure 7(b) is the H-plane active standing wave curve of the present invention without the addition of asymmetric branches.

[0033] Figure 8 shows the active standing wave curves of the present invention; wherein, Figure 8(a) is the active standing wave curve of the E-plane without the composite resistive surface loaded in the present invention, and Figure 8(b) is the active standing wave curve of the H-plane without the composite resistive surface loaded in the present invention.

[0034] Figure 9 shows the active standing wave curves of the present invention; wherein, Figure 9(a) is the active standing wave curve of the E-plane of the unloaded structure of the present invention, and Figure 9(b) is the active standing wave curve of the H-plane of the unloaded structure of the present invention.

[0035] Figure 10 is an active standing wave curve diagram of the present invention; wherein, Figure 10(a) is the active standing wave diagram of the antenna E-plane, and Figure 10(b) is the active standing wave diagram of the H-plane.

[0036] Among them, 10 is a periodic surface; 11 is a cross-shaped metal patch; 12 is a first dielectric substrate; 20 is a dipole; 30 is a curvature-gradient balun; 40 is an asymmetric branch; 41 is a metal pillar; 42 is a vertical metal extension patch; 43 is a horizontal metal extension patch; 50 is a composite resistive structure; 51 is an upper resistive surface structure; 52 is a symmetrical metal grid structure; 53 is a resistive surface; 54 is a second dielectric substrate; 55 is a symmetrical metal grid patch; 56 is a third dielectric substrate; 61 is a first short-circuit post; 62 is a second short-circuit post; 63 is a first rectangular metal strip; 64 is a first resistor; 65 is a second rectangular metal strip; 66 is a second resistor; 70 is a power-fed dielectric substrate; 80 is a ground plane; 81 is a coaxial connector; and 82 is a bottom dielectric substrate. Detailed Implementation

[0037] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0038] To address the problems of existing technologies, this invention improves the wideband and wide-angle active standing wave characteristics while saving antenna design space.

[0039] like Figure 1As shown, an ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning includes N*N periodically arranged dual-polarization units, where N≥2. Each dual-polarization unit includes a ground plane 80, and a feeding dielectric substrate 70 is vertically placed above the ground plane 80. Curvature-gradient baluns 30 and wedge dipoles 20 are printed on both sides of the feeding dielectric substrate 70. The wedge dipoles 20 are located above the curvature-gradient baluns 30, and the upper port of the curvature-gradient baluns 30 is connected to the wedge dipole 20. The lower port of the gradually curvature balun 30 is connected to the ground plane 80. A periodic surface 10 is provided above the wedge dipole 20. The two sides of the feed dielectric substrate 70 are respectively attached with a first short-circuit post 61 and a second short-circuit post 62, and the first short-circuit post 61 and the second short-circuit post 62 are located on both sides of the gradually curvature balun 30. An asymmetric branch 40 is printed on the feed dielectric substrate 70 on the back of the first short-circuit post 61. The first short-circuit post 61 is connected to the asymmetric branch 40.

[0040] The actual antenna array of this invention is composed of these periodic elements forming an 8x8 phased array. For ease of demonstration, Figure 1 Only one unit is drawn in the middle.

[0041] The lateral area of ​​the dual-polarization unit is 19.09mm*19.09mm, and the overall profile height of the antenna is 42.0mm-43.0mm.

[0042] A composite resistive structure 50 is horizontally disposed between the wedge dipole 20 and the floor 80. The composite resistive structure 50 includes an upper resistive surface structure 51 and a symmetrical metal grid structure 52. The upper resistive surface structure 51 is located above the symmetrical metal grid structure 52.

[0043] The floor 80 includes a bottom dielectric substrate 82 placed horizontally at the bottom and a coaxial connector 81 located on the bottom dielectric substrate 82. The coaxial connector 81 is connected to the lower port of the curvature gradient balun 30. The material of the bottom dielectric substrate 82 is FR4.

[0044] The feed dielectric substrate 70 is made of Rogers 4003C with a dielectric constant of 3.55 and a loss tangent of 0.0027.

[0045] The bottom side of the gradually curvature balun 30 has a width of 3.00mm-3.50mm and a curvature of 1 on one side, and a width of 2.00mm-2.30mm and a curvature of 108 on the other side. The feed line height is 23.5mm-24.5mm. The wedge dipole 20 has a height of 12.4mm-12.8mm, an upper width of 5.8mm-6.2mm, and a lower width of 10.2mm-11.2mm.

[0046] like Figure 2 , Figure 3As shown, the asymmetric branch 40 includes a vertical metal extension patch 42 printed on the edge of the feed dielectric substrate 70 and a horizontal metal extension patch 43 etched on the ground plane 80. The vertical metal extension patch 42 is connected to the ground side of the curvature gradient balun 30, the horizontal metal extension patch 43 is connected to the second short-circuit post 62, and the vertical metal extension patch 42 is connected to the first short-circuit post 61 through the metal post 41.

[0047] The metal column 41 in the asymmetric branch 40 has a width of 1.4mm-1.6mm, the vertical metal extension patch 42 has a height of 15mm-16mm and a width of 0.3mm-0.5mm, and the horizontal metal extension patch 43 has a length of 6mm-7mm and a width of 0.3mm-0.5mm.

[0048] Both the vertical metal extension patch 42 and the horizontal metal extension patch 43 are loaded between the wedge dipole 20 and the floor 80.

[0049] The first short-circuit post 61 is connected to the ground side of the curvature gradient balun 30, and the second short-circuit post 62, which is not connected to the ground side of the curvature gradient balun 30, connects the wedge dipole 20 to the ground plane 80. Both the first short-circuit post 61 and the second short-circuit post 62 are printed on the feed dielectric substrate 70.

[0050] The first short-circuit post 61 is composed of a first rectangular metal strip 63 and a first resistor 64 thereon; the second short-circuit post 62 is composed of a second rectangular metal strip 65 and a second resistor 66 thereon, and the resistance values ​​of the first resistor 64 and the second resistor 66 are both 50Ω.

[0051] like Figure 4 As shown, the periodic surface 10 includes a first dielectric substrate 12, on which a 7*7 cross-shaped metal patch 11 is attached; the cross rectangle size of a single unit of the cross-shaped metal patch 11 is (0.3mm-0.4mm)*(1.6mm-2mm), the material of the first dielectric substrate 12 is FR4, the dielectric constant is 4.4, and the loss tangent is 0.002.

[0052] As shown in Figure 5, the upper resistive surface structure 51 includes a second dielectric substrate 54, on which a resistive surface 53 is printed. The resistive surface 53 has a resistance of 377Ω. The material of the second dielectric substrate 54 is FR4, with a dielectric constant of 4.4 and a loss tangent of 0.02. The symmetrical metal grid structure 52 is composed of orthogonal rectangular metal strips and includes a symmetrical metal grid patch 55 and a third dielectric substrate 56. The material of the third dielectric substrate 56 is FR4, with a dielectric constant of 4.4 and a loss tangent of 0.02.

[0053] The upper resistive surface structure 51 has an overall height of 10mm-11mm; the lower metal grid structure 52 has a cross rectangle size of (0.8mm-1.2mm)*19.09mm and an overall height of 8.5mm-9.5mm.

[0054] The antenna is dual-polarized. When firing from the side, it has an active VSWR ≤ 2.5 in the E-plane operating frequency band of 0.34GHz-9.44GHz (27.76:1) and an active VSWR ≤ 2.5 in the H-plane operating frequency band of 0.34GHz-9.68GHz (28.47:1). When the E-plane scanning angle reaches ±60°, it has an active VSWR ≤ 3 in the operating frequency band of 0.3GHz-8.62GHz (28.73:1) and an active VSWR ≤ 3 in the H-plane operating frequency band of 0.3GHz-9.14GHz (30.47:1). The antenna profile height is 0.042λ.

[0055] As shown in Figure 5(a), the upper resistive surface structure 51 includes a resistive surface 53 and a second dielectric substrate 54. The resistive surface 53 has a resistance of 377Ω and is printed on the second dielectric substrate 54. The material of the second dielectric substrate 54 is FR4, the dielectric constant is 4.4, and the loss tangent is 0.02. As shown in Figure 5(b), the lower symmetrical metal grid structure 52 includes a symmetrical metal grid patch 55 and a third dielectric substrate 56. The material of the third dielectric substrate 56 is FR4, the dielectric constant is 4.4, and the loss tangent is 0.02.

[0056] Figure 6(a) shows the active standing wave ratio (VSWR) in the E-plane without the periodic surface proposed in this invention, and Figure 6(b) shows the active VSWR in the H-plane without the periodic surface proposed in this invention. The comparison shows that after loading the periodic surface, the active VSWR in the E-plane at 5.5 GHz-6.5 GHz is improved, and the active VSWR in the H-plane at 3 GHz-8.5 GHz decreases and becomes smoother.

[0057] Figure 7(a) shows the E-plane active standing wave diagram without the addition of asymmetric stubs, and Figure 7(b) shows the H-plane active standing wave diagram without the addition of asymmetric stubs. The comparison shows that after adding asymmetric stubs, the low-frequency and high-frequency active standing waves at the E-plane end-fire are significantly reduced, and the bandwidth is broadened; the H-plane active standing wave ratio is significantly improved overall, and the bandwidth is broadened.

[0058] Figure 8(a) shows the E-plane active standing wave ratio (VSWR) without the composite resistive surface, and Figure 8(b) shows the H-plane active VSWR without the composite resistive surface. The comparison shows that after loading the composite resistive structure, the active VSWR decreases and becomes smoother, with a particularly significant improvement in the H-plane active VSWR and a relatively wider bandwidth.

[0059] Figure 9(a) shows the active standing wave ratio (VSWR) of the E-plane without the structure, and Figure 9(b) shows the active VSWR of the H-plane without the structure. Figure 10(a) shows the active VSWR of the antenna E-plane, and Figure 10(b) shows the active VSWR of the antenna H-plane. The comparison shows that the periodic surface, asymmetric stubs, and composite resistive structure work together to improve the active VSWR ratio of the antenna E-plane and H-plane and expand the bandwidth.

[0060] Application prospects of this invention

[0061] Existing dual-polarized tightly coupled array antennas can achieve good wide-bandwidth angle scanning characteristics in the E-plane and D-plane, but are not ideal for wide-bandwidth angle scanning targets in the H-plane. This invention enables the antenna to possess ultra-wideband, wide-angle, and low-profile characteristics when scanning in the H-plane, making it suitable for multi-functional radar, electronic countermeasures, and communications. Dual-polarization technology can improve the probability of target detection and identification in radar applications. In various time-domain radar applications requiring high-resolution imaging, such as collision avoidance radar, biomedical detection, and through-wall radar, the bandwidth advantage of ultra-wideband array antennas also plays a crucial role. Applied to the array antenna design of phased array radar systems, this enables the radar to have large-angle phase scanning capabilities within an ultra-wide bandwidth. In addition to meeting the required operating bandwidth, it also expands the system's communication and detection range and reduces communication and detection blind spots.

[0062] The periodic surface 10 proposed in this invention is composed of 7*7 cross-shaped metal patches. The lower structure of the composite resistive structure 50 is a grid structure orthogonally formed by rectangular metal surfaces. The operating frequency of the composite resistive structure 50 is related to the overall height from the ground. When parameters such as the size of the metal patches, the size of the resistive surface, and the width and spacing of the rectangular metal units in the lower grid structure are changed, the composite virtual ground structure can still achieve the purpose of the invention.

Claims

1. An ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning, characterized in that: The system comprises N*N periodically arranged dual-polarization units, where N≥2. Each dual-polarization unit includes a ground plane (80), and a feeding dielectric substrate (70) is vertically placed above the ground plane (80). Both sides of the feeding dielectric substrate (70) are printed with a curvature gradient balun (30) and a wedge dipole (20). The wedge dipole (20) is located above the curvature gradient balun (30). The upper port of the curvature gradient balun (30) is connected to the wedge dipole (20), and the lower port of the curvature gradient balun (30) is connected to the ground plane. The plates (80) are connected, and a periodic surface (10) is provided above the wedge dipole (20). The first short-circuit post (61) and the second short-circuit post (62) are respectively attached to the two sides of the feed dielectric substrate (70). The first short-circuit post (61) and the second short-circuit post (62) are located on both sides of the curvature gradient balun (30). An asymmetric branch (40) is printed on the feed dielectric substrate (70) on the back of the first short-circuit post (61). The first short-circuit post (61) is connected to the asymmetric branch (40). The asymmetric branch (40) includes a vertical metal extension patch (42) printed on the edge of the feed dielectric substrate (70) and a horizontal metal extension patch (43) etched on the ground plane (80). The vertical metal extension patch (42) is connected to the ground side of the curvature gradient balun (30), the horizontal metal extension patch (43) is connected to the second short-circuit post (62), and the vertical metal extension patch (42) is connected to the first short-circuit post (61) through the metal post (41). Both the vertical metal extension patch (42) and the horizontal metal extension patch (43) are loaded between the wedge dipole (20) and the floor (80).

2. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 1, characterized in that: The floor (80) includes a bottom dielectric substrate (82) placed horizontally at the bottom and a coaxial connector (81) located on the bottom dielectric substrate (82), the coaxial connector (81) being connected to the lower port of the curvature gradient balun (30).

3. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning as described in claim 1, characterized in that: A composite resistive structure (50) is horizontally disposed between the wedge dipole (20) and the floor (80). The composite resistive structure (50) includes an upper resistive surface structure (51) and a symmetrical metal grid structure (52). The upper resistive surface structure (51) is located above the symmetrical metal grid structure (52).

4. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 1, characterized in that: The first short-circuit post (61) is composed of a first rectangular metal strip (63) and a first resistor (64) thereon; the second short-circuit post (62) is composed of a second rectangular metal strip (65) and a second resistor (66) thereon.

5. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 1, characterized in that: The periodic surface (10) includes a first dielectric substrate (12), on which a cross-shaped metal patch (11) is attached. The cross rectangle of a single unit of the cross-shaped metal patch (11) has dimensions of (0.3mm-0.4mm)*(1.6mm-2mm).

6. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 3, characterized in that: The upper resistive surface structure (51) includes a second dielectric substrate (54) on which a resistive surface (53) is printed; the symmetrical metal grid structure (52) is composed of orthogonal rectangular metal strips and includes a symmetrical metal grid patch (55) and a third dielectric substrate (56). The overall height of the upper resistive surface structure (51) is 10mm-11mm; the cross rectangle size of the symmetrical metal grid structure (52) is (0.8mm-1.2mm)*19.09mm, and the overall height is 8.5mm-9.5mm.

7. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 1, characterized in that: The lateral side length of the dual-polarization unit is (19.00mm-19.55mm)*(19.00mm-19.55mm), and the overall profile height of the antenna is 42.0mm-43.0mm.

8. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 1, characterized in that: The bottom side of the gradually curvature balun (30) has a width of 3.00mm-3.50mm and a curvature of 10, while the other side has a width of 2.00mm-2.30mm and a curvature of 108. The feed line height is 23.5mm-24.5mm. The wedge dipole (20) has a height of 12.4mm-12.8mm, an upper width of 5.8mm-6.2mm, and a lower width of 10.2mm-11.2mm.

9. The ultra-low profile dual-polarization array based on tight coupling to achieve ultra-wide bandwidth angle scanning according to claim 1, characterized in that: The metal column (41) in the asymmetric branch (40) has a width of 1.4mm-1.6mm, the vertical metal extension patch (42) has a height of 15mm-16mm and a width of 0.3mm-0.5mm, and the horizontal metal extension patch (43) has a length of 6mm-7mm and a width of 0.3mm-0.5mm.

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