A conformal dual-polarized low-scattering array antenna

Abstract

The present application relates to the field of low scattering array antenna, and particularly relates to a conformal dual-polarized low scattering array antenna. The scheme comprises a dielectric substrate 1, a dipole radiation patch 2, a parasitic patch 3, a wave absorbing material 4, a feed balun 5, and a metal floor 6. The dielectric substrate 1 is conformal to the outer skin of a platform. The dipole radiation patch 2 is printed on the upper surface of the dielectric substrate 1 after being shaped and hollowed. The parasitic patch 3 is printed on the lower surface of the dielectric substrate 1. The wave absorbing material 4 is attached to the lower surface of the dielectric substrate 1 and is conformal to the dielectric substrate 1. The feed balun 5 penetrates the dielectric substrate 1, the wave absorbing material 4 and the metal floor 6 and is connected to the two side radiation arms of the dipole radiation patch 2 respectively. The present application can effectively reduce the antenna scattering by shaping and hollowing the dipole radiation patch. The space below the dielectric substrate is loaded with a parasitic structure and a wave absorbing material, which can improve the standing wave performance and reduce the scattering. The present application is suitable for stealth platforms.

Description

Technical Field

[0001] This invention relates to the field of low-scattering array antennas, and more specifically to a conformal dual-polarized low-scattering array antenna. Background Technology

[0002] The concept of stealth platforms has garnered widespread attention since its inception. Stealth, as the name suggests, means invisible, and in practical military applications, it refers to being undetectable by radar. Due to its enhanced survivability and penetration capabilities, stealth technology has gradually become a popular development direction for modern combat platforms. Stealth utilizes various technological means to reduce or suppress the scattered echo signals of a detected target.

[0003] With the rapid development of military electronic technology, the survivability and combat capabilities of various platforms are facing increasing challenges, making the stealth performance of modern platforms even more crucial. As one of the strongest scattering sources for various platforms, the scattering performance of antennas significantly impacts the platform's stealth capabilities. This necessitates that array antennas possess not only excellent radiation performance but also good scattering performance. Therefore, modern stealth platforms urgently require antennas with low profile, ultra-wideband, large scan angle, conformal design, and low scattering characteristics. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a conformal dual-polarized low-scattering array antenna that effectively reduces antenna scattering.

[0005] The present invention achieves the above objectives by adopting the following technical solution: The present invention provides a conformal dual-polarized low-scatter array antenna, comprising: a dielectric substrate 1, a dipole radiating patch 2, a parasitic patch 3, an absorbing material 4, a feed balun 5, and a metal ground plane 6. The dielectric substrate 1 is conformally fitted to the outer skin of the platform. The dipole radiating patch 2, after being shaped and hollowed out, is printed on the upper surface of the dielectric substrate 1. The parasitic patch 3 is printed on the lower surface of the dielectric substrate 1. The absorbing material 4 is attached to the lower surface of the dielectric substrate 1 and conformally fitted to the dielectric substrate 1. The feed balun 5 penetrates the dielectric substrate 1, the absorbing material 4, and the metal ground plane 6, and is connected to the two radiating arms on both sides of the dipole radiating patch 2 for feeding.

[0006] Furthermore, the dipole radiating patch 2 is arrayed in a tight coupling manner, coupling the vertical polarization and the horizontal polarization together in a cross-shaped coupling method. The coupling points are formed at the ends of the radiating arms of adjacent units and the gaps between units. The coupling strength between units is controlled by controlling the size and shape of the gaps.

[0007] Furthermore, the parasitic patch 3 is located directly below the coupling center of the dipole radiating patch 2. The shape of the parasitic patch 3 is square, circular, or elliptical. The coupling effect of the parasitic patch 3 is the same as the coupling effect of the radiating arms of the adjacent vertically and horizontally polarized units of the dipole radiating patch 2.

[0008] Furthermore, the shaping process of the dipole radiating patch 2 involves shaping the ends of the radiating arms or the feeding ends of the dipole radiating patch 2, specifically by chamfering. The chamfering methods include oblique straight cuts to form wedges and triangles, or elliptical, hyperbolic, parabolic, or exponentially gradual cuts.

[0009] Furthermore, the dipole radiation patch 2 is hollowed out at its center, and the shape of the hollowed-out opening is a shape that surrounds the center of the radiation arm, such as a trapezoid, triangle, circle, fan, or square.

[0010] Furthermore, the absorbing material 4 comprises two layers: the upper layer is PP or PMI rigid foam, and the lower layer is an absorbing adhesive sheet; or the upper and lower layers are made of the same absorbing material, and the single absorbing material has a gradient layered structure. Through layering, impedance adjustment is achieved.

[0011] Furthermore, the feeding balun 5 uses a gradient feeding method with patch-type radial arms on both sides.

[0012] The beneficial effects of this invention are as follows:

[0013] This invention effectively reduces antenna scattering by modifying and hollowing out the dipole radiating patch. It conforms to the outer skin of the platform, which is beneficial for platform integration and achieving low scattering of the overall platform. The small spacing of the radiating units facilitates large-angle wave velocity scanning. Parasitic structures and absorbing materials are loaded in the space below the dielectric substrate, which can improve standing wave performance and reduce scattering. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a conformal dual-polarized low-scattering array antenna structure provided by the present invention;

[0015] Figure 2 This is a schematic diagram of the hollow area of ​​the dipole radiating patch provided by the present invention;

[0016] Figure 3 This is a schematic diagram of the shape of the dipole radiating patch provided by the present invention after it has been hollowed out;

[0017] Figure 4 This is a schematic diagram of the hollowed-out area of ​​the sector-shaped dipole radiating patch provided by the present invention;

[0018] Figure 5This is a schematic diagram of the shape of the fan-shaped dipole radiating patch after it has been hollowed out, provided by the present invention.

[0019] Figure 6 This is a top view of the conformal dual-polarized low-scatter array antenna dipole radiating patch after being hollowed out, provided by the present invention.

[0020] Figure 7 This is a schematic diagram of the structure provided by the present invention after removing the dipole radiation patch and the dielectric layer;

[0021] Figure 8 and Figure 9 These are the active standing wave ratios of the conformal dual-polarized low-scatter array antenna provided by this invention during 0° and 50° scanning in vertical and horizontal polarization, respectively.

[0022] Figure 10 and Figure 11 These are comparison diagrams of the effective gain of the conformal dual-polarized low-scatter array antenna provided by the present invention during 0° and 50° scanning with vertical polarization and horizontal polarization at an angle θ.

[0023] Figure 12 and Figure 13 These are comparison diagrams of the radar cross sections of the modified array and the unmodified array provided by this invention at a certain frequency point in the S-band under vertical and horizontal polarization.

[0024] Figure 14 and Figure 15 These are comparison diagrams of the radar cross sections of the modified and unmodified arrays provided by this invention at a certain frequency point in the X-band under vertical and horizontal polarization.

[0025] In the attached diagram, 1 is the dielectric substrate, 2 is the dipole radiating patch, 3 is the parasitic patch, 4 is the absorbing material, 5 is the feed balun, and 6 is the metal ground plane. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0027] This invention provides a conformal dual-polarized low-scattering array antenna, such as... Figures 1 to 7 As shown, it includes: a dielectric substrate 1, a dipole radiating patch 2, a parasitic patch 3, a microwave absorbing material 4, a power balun 5, and a metal ground plane 6.

[0028] The dielectric substrate 1 is conformally fitted to the outer skin of the platform, and its material can be flexible materials such as polyimide and polyester.

[0029] The modified and hollowed-out dipole radiating patch 2 is printed on the upper surface of the dielectric substrate 1 and arrayed in a tight coupling manner, i.e., a tightly coupled arrangement. Specifically, it includes arraying along the horizontal direction and arraying along the vertical polarization direction, i.e., coupling vertical polarization and horizontal polarization together. The coupling method is a cross-shaped arrangement, with gaps between adjacent units. The ends of the radiating arms of adjacent units and the gaps between units form coupling points. The coupling strength between units can be controlled by controlling the size of the gaps and the modified shape.

[0030] The primary innovation of this invention is the modification of the ends or feed ends of the dipole radiating patch 2, and the removal of the central portions of the radiating arms on both sides of the array element, because edge scattering is relatively strong in these areas, or the surface current is weak during radiation and strong during scattering. Through these treatments, antenna scattering reduction can be achieved.

[0031] Specifically, the ends or feed terminals of the radiating arms of the dipole radiating patch 2, which have undergone shaping and hollowing-out treatment, can be further modified, specifically by chamfering. Chamfering methods include oblique straight cuts to form wedges or triangles, but elliptical, hyperbolic, parabolic, or exponentially gradient forms can also be used. Through chamfering and other shaping methods, without affecting radiation performance and coupling characteristics, optimizing the removed metal portion and adjusting the remaining metal or even dielectric boundaries can help reduce electromagnetic scattering of the antenna.

[0032] Each dipole radiating patch array element, after being shaped and perforated, has metal perforations at its center on both radiating arms. At the center of the radiating arm, the surface current is weak during radiation and strong during scattering. Perforation reduces the surface area of ​​the metal patch with minimal impact on radiation, thereby reducing the antenna's radar cross-section. The shape of the perforation opening is a shape surrounding the center of the radiating arm, including but not limited to trapezoidal, triangular, circular, fan-shaped, or square shapes. The perforated area of ​​the dipole radiating patch is as follows: Figure 2 As shown, the shape of the dipole radiating patch after being hollowed out is as follows: Figure 3 As shown, the hollowed-out area of ​​the fan-shaped dipole radiating patch is as follows: Figure 4 As shown, the shape of the fan-shaped dipole radiating patch after being hollowed out is as follows: Figure 5 As shown.

[0033] Parasitic patch 3 is printed on the lower surface of dielectric substrate 1, and is also located directly below the center of the coupling point of the modified and hollowed-out dipole radiating patch 2. The shape of parasitic patch 3 can be square, circular, elliptical, etc., and it has the same coupling effect as the radiating arms of adjacent vertically and horizontally polarized elements. Its function is to broaden the low-frequency bandwidth by enhancing the coupling effect. To further expand antenna performance, dielectric substrate 1 can be a single layer, a double layer, or a multi-layer board. When it is a multi-layer board, parasitic patch 3 is located in the middle layer or on the lower surface of the multi-layer board. A top view of the conformal dual-polarized low-scatter array antenna dipole radiating patch after hollowing out is shown below. Figure 6 As shown, the structure after removing the dipole radiating patch and the dielectric layer is as follows: Figure 7 As shown.

[0034] The absorbing material 4 is located on the upper surface of the metal floor 6 and conforms to the metal floor 6, or on the lower surface of the dielectric substrate 1 and conforms to the dielectric substrate 1. The absorbing material can be of various types, such as foam, adhesive sheet, honeycomb, or a combination thereof. For example, the absorbing material can be two layers: the upper layer is PP or PMI rigid foam, which has a relatively low relative permittivity, is lightweight, and has a slightly weaker absorbing effect; the lower layer can be an absorbing adhesive sheet, which has a relatively high relative permittivity and permeability, resulting in better absorbing effect, but is heavier. Therefore, using two absorbing materials together allows for a balance between weight and absorbing effect. Simultaneously, a single absorbing material can also have a gradient layered structure. Through layering, impedance adjustment is achieved, which is more conducive to matching with air impedance.

[0035] The feeding balun 5 runs through the dielectric substrate 1, the absorbing material 4, and the metal ground plane 6, and is connected to the two radiating arms on both sides of the dipole radiating patch 2 for feeding.

[0036] Specifically, the fed balun has a gradient feed line printed on a dielectric substrate. Openings are made in the dielectric substrate, absorbing material, and metal ground plane, through which the balun feeds the radiating arms on both sides of the dipole and also performs impedance transformation. Furthermore, the good standing wave ratio (SWR) performance of the fed balun can also optimize the antenna's SWR performance to some extent.

[0037] Figure 8 and Figure 9 These are comparison charts showing the active standing wave ratio (VSWR) of the conformal dual-polarized low-scattering array antenna of this invention under vertical and horizontal polarization scanning conditions of 0 degrees and 50 degrees, respectively. It can be seen that the active VSWR is less than 3 in all cases, and less than 2.5 in most frequency bands within the band, indicating that this array antenna has excellent VSWR performance.

[0038] Figure 10 The conformal dual-polarized low-scatter array antenna of this invention is in 4 fThe radiation patterns for 0° and 50° vertical polarization scans. The maximum achievable gain at 0° is 10.70 dBi, and the maximum achievable gain at 50° is 5.84 dBi.

[0039] Figure 11 The conformal dual-polarized low-scattering array antenna of this invention is in 4 f The radiation patterns of 0° and 50° horizontal polarization scans. The maximum achievable gain at 0° is 10.34 dBi, and the maximum achievable gain at 50° is 6.46 dBi.

[0040] Figure 12 and Figure 13 The figures show a comparison of the monostatic radar cross sections (RCS) of the modified and unmodified arrays illuminated by vertically and horizontally polarized radar waves at a specific frequency in the S-band. Under VV polarization, the modified array shows a 1.02 dBsm reduction in RCS compared to the unmodified array, while under HH polarization, the modified array shows a 2.51 dBsm reduction in RCS compared to the unmodified array.

[0041] Figure 14 and Figure 15 The figures show a comparison of the monostatic radar cross sections (RCS) of the modified and unmodified arrays illuminated by vertically and horizontally polarized radar waves at a specific frequency in the X-band. Under VV polarization, the modified array exhibits a 5.13 dBsm reduction in RCS compared to the unmodified array, while under HH polarization, the modified array exhibits a 2.16 dBsm reduction in RCS compared to the unmodified array.

[0042] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A conformal dual-polarized low-scattering array antenna, characterized in that, The application relates to a dielectric substrate (1), a dipole radiation patch (2), a parasitic patch (3), wave-absorbing material (4), a feed balun (5) and a metal floor (6), wherein the dielectric substrate (1) is conformal to the outer skin of a platform, the dipole radiation patch (2) is printed on the upper surface of the dielectric substrate (1) after being shaped and treated by being hollowed out, the parasitic patch (3) is printed on the lower surface of the dielectric substrate (1), the wave-absorbing material (4) is attached to the lower surface of the dielectric substrate (1) and is conformal to the dielectric substrate (1), and the feed balun (5) penetrates through the dielectric substrate (1), the wave-absorbing material (4) and the metal floor (6) and is connected with the two side radiation arms of the dipole radiation patch (2) to feed power. The dipole radiation patch (2) is arranged in an array through tight coupling, vertical polarization and horizontal polarization are coupled together, the coupling mode is cross, the coupling position is formed by the end of the radiation arm of the adjacent unit and the gap between the units, and the coupling strength between the units is controlled by controlling the size and shaped of the gap. The parasitic patch (3) is located directly below the coupling center of the dipole radiation patch (2), the parasitic patch (3) is square, circular or elliptical, and the coupling effect of the parasitic patch (3) is the same as the coupling effect of the radiation arm of the adjacent unit of the vertical polarization and the horizontal polarization of the dipole radiation patch (2). The dipole radiation patch (2) comprises a wedge-shaped or triangular or fan-shaped end formed by angle cutting, the tip of the end is away from the feeding end, and the end has a hollowed-out area with the same profile shape as the end. The shaping treatment of the dipole radiation patch (2) is related to the end or the feeding end of the radiation arm of the dipole radiation patch (2), and the specific shaping treatment is angle cutting, the angle cutting mode comprises straight cutting to form a wedge and a triangle, or an elliptical, hyperbolic, parabolic or exponential gradient mode. The hollowing-out treatment of the dipole radiation patch (2) is to hollow out the center of the dipole radiation patch (2), the hollowing-out hole shape is a shape surrounding the center of the radiation arm, and the shape is trapezoidal, triangular, circular, fan-shaped or square. The wave-absorbing material (4) comprises two layers, the upper layer is PP or PMI hard foam, the lower layer is a wave-absorbing adhesive plate, or the two layers are the same kind of wave-absorbing material, and the single wave-absorbing material is a gradient gradient layered structure, and the impedance is adjusted through layering. The feed balun (5) is used for feeding the two side radiation arms of the patch in a gradient mode. ​

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