A broadband vertically polarized directional antenna and an airborne over-the-top blind-filling method

Abstract

The application discloses a broadband vertical polarization directional antenna and an airborne over-the-top blind-filling method, and belongs to the field of communication antennas. The antenna comprises a spherical conformal metal floor which is conformal to the surface of a mounting carrier; and a plurality of single magnetic dipole units which are arranged in a ring array on the surface of the spherical metal floor. The single magnetic dipole unit comprises a metal reflecting platform, a feeding probe and a bent metal radiation arm. The metal reflecting platform is inlaid on the surface of the spherical metal floor. The bent metal radiation arm comprises a vertical feeding section, a horizontal radiation section and a grounding section. The grounding section is connected with the metal reflecting platform, the vertical feeding section is parallel to the grounding section, and the horizontal radiation section is connected between the vertical feeding section and the grounding section. One end of the feeding probe is connected with the vertical feeding section through the metal platform, and the other end is connected with a feeding network.

Description

Technical Field

[0001] This invention relates to the field of communication antennas, specifically to a broadband vertically polarized directional antenna and an airborne over-the-top blind spot compensation method. Background Technology

[0002] In recent years, with the rapid growth in demand for aviation communication, airborne communication systems have faced severe technical challenges. Currently, aircraft airborne antenna systems generally employ polarization isolation schemes: the rear antenna uses a horizontal polarization design, while the belly antenna uses vertical polarization to avoid polarization crosstalk with the rear antenna. However, this traditional approach has an inherent drawback—the vertically polarized antenna will naturally generate a radiation null in the Z-axis 0° direction (i.e., directly below the aircraft), creating a communication dead zone.

[0003] This technical bottleneck means that the vertical communication link of the belly antenna is easily interrupted when the aircraft is climbing, circling, or flying at low altitudes, especially during takeoff and landing. Existing solutions mainly employ two approaches: one is to increase the number of auxiliary antennas, but this significantly increases system weight and complexity; the other is to increase transmission power, which not only wastes energy but may also introduce electromagnetic compatibility issues. More seriously, neither of these solutions can fundamentally solve the radiation null problem of vertically polarized antennas in the overhead region. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a broadband vertically polarized directional antenna and an airborne over-the-top blind spot compensation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A first aspect of the present invention relates to an antenna, comprising:

[0007] Spherical conformal metal floor, conformally matched to the surface of the mounting carrier;

[0008] And multiple single magnetic dipole units arranged in a ring array on the surface of the spherical metal floor;

[0009] The single magnetic dipole unit includes a metal reflector, a feed probe, and a bent metal radiating arm.

[0010] The metal reflector is embedded in the surface of the spherical metal floor.

[0011] The bent metal radiating arm includes a vertical feeding section, a horizontal radiating section, and a grounding section;

[0012] The grounding section is connected to the metal reflector surface, the vertical feed section is parallel to the grounding section, and the horizontal radiation section is connected between the vertical feed section and the grounding section.

[0013] One end of the power supply probe passes through the metal platform and connects to the vertical power supply section, while the other end connects to the power supply network.

[0014] Optionally, the angle between the metal reflector surface and the horizontal plane is 54 degrees.

[0015] Optionally, the metal reflector surface has an opening or groove in the middle to accommodate the feed probe.

[0016] Optionally, the bent metal radiating arm, the spherical conformal metal floor, and the metal reflector are all made of copper.

[0017] The coupling feed probe is made of copper and has an overall size of 8mm in length, 1.37mm in width, and 0.8mm in thickness. It maintains a 0.32mm gap with the vertical feed section of the bent metal radiating arm. The optimized geometry achieves efficient electromagnetic coupling while ensuring impedance matching characteristics.

[0018] Optionally, the metal reflector surface is kept parallel to the horizontal radiation section.

[0019] Optionally, the annular arrangement of single magnetic dipole units includes two sets of single magnetic dipole units arranged in a circular array, wherein the number of single magnetic dipole units in the inner ring is 4, and the number of single magnetic dipole units in the outer ring is 8; the line connecting the midpoint of the horizontal radiation segment of the inner ring to the center of the spherical conformal metal ground plane makes an angle of 14 degrees with the Z-axis; the line connecting the midpoint of the horizontal radiation segment of the outer ring to the center of the spherical conformal metal ground plane makes an angle of 28 degrees with the Z-axis.

[0020] Optionally, the spacing between the single magnetic dipole units is half the wavelength corresponding to the operating frequency.

[0021] Optionally, there is a height difference between the horizontal radiation sections of the single magnetic dipole units of the inner and outer rings.

[0022] A second aspect of the present invention relates to a method for blind spot control of a broadband vertically polarized antenna, comprising the following steps:

[0023] By calculating the path difference between the inner and outer single magnetic dipole units of the antenna in the Z-axis direction, and determining the required phase compensation value accordingly, the electromagnetic waves radiated by the two rings of units are superimposed in phase in space by adjusting the feed network, thereby accurately concentrating the maximum vertical polarization gain in the +Z-axis direction.

[0024] Optionally, the phase difference caused by the path difference is The specific calculation formula is as follows:

[0025]

[0026] in c It's the speed of light. It's frequency. d This is the path difference.

[0027] A third aspect of the invention relates to an airborne communication system comprising the antenna described above.

[0028] The beneficial effects of this invention are:

[0029] 1. This invention effectively solves the radiation null problem of traditional vertically polarized antennas in the Z-axis 0° direction in the C-band (5.4-6.4GHz) through an innovative three-segment bent metal radiating arm design for a single magnetic dipole antenna and a 54° tilted metal reflector structure. This design achieves high-gain vertically polarized beam coverage of 13.64dB in the headspace region while maintaining excellent impedance matching characteristics throughout the entire operating frequency band (5.4GHz~6.4GHz). <-10dB). In particular, the optimized 54° reflector tilt angle ensures performance stability under broadband operating conditions. This innovative structural design not only significantly improves the reliability of the airborne communication system, but also enhances the system's adaptability to different communication protocols through its broadband characteristics, providing a reliable technical solution for next-generation aviation communication systems.

[0030] 2. The conformal antenna array of the present invention adopts a spherical integrated design. It perfectly matches the aircraft fuselage with a precise 110mm radius hemispherical metal floor. Combined with the double-layer array arrangement (4 elements in the first ring and 8 elements in the second ring) and half-wavelength spacing control, it achieves excellent radiation performance while maintaining structural compactness.

[0031] 3. The unique phase compensation method of this invention achieves in-phase superposition of spatial radiation current by feeding opposing units with a phase difference of 180° and by accurately calculating the path difference between the two ring units and applying precise phase compensation, so that the main beam is accurately pointed in the +Z axis 0° direction, perfectly adapting to various flight attitudes of the aircraft. Attached Figure Description

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] Figure 1 (a) is a schematic diagram of the overall structure of the C-band airborne broadband vertical polarization blind spot filling conformal antenna array in an embodiment of the present invention; (b) front view; (c) auxiliary view;

[0034] Figure 2 This is a top view of the three-segment bent metal radiating arm structure of the single magnetic dipole antenna element of the present invention;

[0035] Figure 3 This is a side view of the first ring of the single magnetic dipole antenna unit and the metal reflector surface of the present invention;

[0036] Figure 4 This is a side view of the second-circle single magnetic dipole antenna unit and the metal reflector surface of the present invention.

[0037] Figure 5 This is a schematic diagram showing the positions of the first and second rings of the single magnetic dipole unit of the present invention;

[0038] Figure 6 This is a schematic diagram of the vertical polarization gain of the horizontally placed antenna element of the present invention.

[0039] Figure 7 This is a schematic diagram of the S-parameter test results of the antenna array of the present invention;

[0040] Figure 8 This is a schematic diagram of the antenna array isolation test results of the present invention;

[0041] Figure 9 This is a schematic diagram of the vertical polarization gain of the antenna array of the present invention;

[0042] Figure 10 This represents the maximum vertical polarization gain of the metal reflector surface of the antenna array in this invention under different tilt angles.

[0043] In the figure: 1: Spherical conformal metal ground plane; 2: Single magnetic dipole unit; 3: Metal reflector platform; 4: Coupled feed probe. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0045] In some embodiments of the present invention, a broadband vertically polarized directional antenna and an airborne over-the-top blind spot filling method are disclosed. The antenna includes a spherical conformal metal ground plate 1 and single magnetic dipole units 2 arranged in a ring array on the spherical conformal metal ground plate 1. The spherical conformal metal ground plate 1 is mounted on a carrier, and its shape and curvature conformally match the carrier.

[0046] Specifically, the carrier includes, but is not limited to, vehicles capable of moving on land, wearable devices, or aircraft. The spherical conformal metal floor 1 is made of a highly conductive metal material, and its surface may be coated with an anti-oxidation coating.

[0047] In some specific embodiments of the present invention, taking an aircraft as an example, the spherical conformal metal floor 1 adopts a hemispherical structure with a radius of 110mm, whose radius of curvature precisely matches the aircraft fuselage skin. This hemispherical structure itself has excellent geometric stability, and achieves structural self-support through its complete surface continuity, maintaining its shape integrity without additional reinforcement.

[0048] The spherical conformal metal floor 1 has an integrated metal reflector 3 on its surface, and the junction between the metal reflector 3 and the spherical conformal metal floor 1 is a curved transition. The spherical conformal metal floor 1 contains a power supply network system, employing a multi-layer wiring structure for signal transmission.

[0049] The single magnetic dipole antenna array consists of multiple identical units. Each unit includes a three-section bent metal radiating arm (vertical feed section 7.6mm×34.38mm, horizontal radiating section 5.36mm×34.38mm, and ground section 10mm×34.38mm), a coaxial feeder, and a rectangular coupled metal feed probe 4 (8mm×1.37mm). The radiating arm is made of copper, a metal material with high conductivity.

[0050] In some specific embodiments of the present invention, the array adopts a double-layer concentric circle arrangement, with 4 units evenly distributed in the first ring and 8 units evenly distributed in the second ring. To meet the half-wavelength spacing and optimize radiation performance, the units in the first ring are spaced 90° apart relative to the Z-axis, and the units in the second ring are spaced 45° apart relative to the Z-axis. At the same time, the first ring of units is rotated 14° relative to the spherical conformal metal ground plane 1, and the second ring of units is rotated 28°. This special arrangement design effectively reduces the coupling between units and achieves the maximum gain synthesis effect.

[0051] The first ring of units has an angle of ∠a = 14° relative to the center of the spherical conformal metal floor 1, and the second ring of units has an angle of ∠b = 28° relative to the center of the spherical conformal metal floor 1, forming a specific spatial phase relationship. More specifically, ∠a is the angle between the line connecting the midpoint of the horizontal radiation segment of the first ring and the center of the spherical conformal metal floor 1, and the Z-axis; ∠b is the angle between the line connecting the midpoint of the horizontal radiation segment of the second ring and the center of the spherical conformal metal floor 1, and the Z-axis.

[0052] The metal reflector surface 3 is made of the same copper material as the spherical conformal metal floor 1, and its overall dimensions are 40mm in length, 20mm in width, and 1.5mm in thickness. The plane of the metal reflector surface 3 is parallel to the second metal radiating arm of the single magnetic dipole unit 2.

[0053] The single magnetic dipole unit 2 is arranged perpendicular to the metal reflector surface 3. The metal reflector surface 3 is inclined at 54°±0.5° relative to the horizontal ground. This angle has been verified by full-wave electromagnetic simulation as the optimal direction angle with the maximum vertical polarization gain.

[0054] Updated: The single magnetic dipole unit 2 is arranged perpendicular to the reflector surface, and the metal reflector surface 3 is inclined at ∠c=54°±0.5° relative to the horizontal ground. This angle has been verified by full-wave electromagnetic simulation as the optimal direction angle with the maximum vertical polarization gain.

[0055] A circular opening is provided in the center of the reflector platform to accommodate the coupling feed probe and connect it through the internal feed network.

[0056] In some embodiments of the present invention, in order to maximize the benefits of the above-mentioned antenna structure, a method for controlling the feed phase and phase compensation is provided, specifically including the following steps:

[0057] For the conformal array arrangement structure, by precisely controlling the feed phase difference between diagonally positioned units to 180°, the spatial current flow direction of each unit is kept in phase; the phase compensation method uses path difference calculation and feed network adjustment to ensure that electromagnetic waves are superimposed in phase in space, thereby accurately pointing the main beam radiation direction to the +Z axis 0° azimuth.

[0058] For the double-layer arrangement structure of the conformal array, the path difference between the four elements of the first ring and the eight elements of the second ring in the Z-axis direction is accurately calculated, and the required phase compensation value is determined accordingly. The method applies a corresponding phase shift to each element by adjusting the feeding network, so that the electromagnetic waves radiated by the two rings of elements are superimposed in phase in space, thereby accurately concentrating the maximum vertical polarization gain in the +Z-axis direction.

[0059] Specifically, the array composed of single magnetic dipole units occupies a limited space of 25mm at the top of the sphere (corresponding to the height of the spherical cap). This highly compact design offers multiple technical advantages: From a spatial layout perspective, the top 25mm height area is specifically used to address the nulling problem of vertically polarized signals within the Z-axis range of 0°±15°, while the remaining approximately 85mm height space on the sphere can be fully utilized to integrate other functional antenna arrays. This vertical spatial partitioning design achieves two core functions: the top blind spot filling array, through an innovative three-segment magnetic dipole structure and a 54° tilted metal reflector platform 3, precisely fills the top blind spot of traditional vertically polarized antennas; the lower space can accommodate forward and lateral scanning arrays, working in conjunction with the top system to construct a complete airspace coverage network. More importantly, this compact 25mm height layout provides ample space for system expansion, while the lower space of the sphere maintains complete conformal surface characteristics, providing sufficient design margin for future system functional expansion. This compact layout design ensures both the high-performance radiation characteristics of the blind spot array and the scalability of the overall system, enabling the antenna system to perfectly adapt to the complex aerodynamic shape of the aircraft and the limited space constraints.

[0060] In some embodiments of the present invention, the specific size design of the above-mentioned antenna array is disclosed, such as... Figure 2 , 3 As shown in Figure 4, each single magnetic dipole unit adopts an innovative three-segment bent metal radiating arm structure design, with a vertical feed segment length of [missing information]. = 7.6mm, width =34.38mm, length of horizontal radiation section =5.36mm, width =34.38mm, grounding section length = 10mm, width =34.38mm. The three-section radiating arm is precision-machined into a single piece, with each section maintaining a consistent width. The unit is equipped with a rectangular coupling feed probe, which is long... = 8mm, width = 1.37mm, maintaining the same width as the vertical feed section. = With a precise spacing of 0.32mm, optimized through electromagnetic field simulation, this design achieves optimal impedance matching characteristics. This unique three-section structure, through electromagnetic coupling between the vertical feed section and the coupling probe, directional radiation of the horizontal radiation section, and the current loop of the grounding section, forms a complete radiation system, effectively solving the radiation null problem in the overhead region of traditional vertically polarized antennas.

[0061] This invention employs an innovative double-layer concentric circle array arrangement scheme, such as... Figure 1 (c) As shown in the top view, the first ring array consists of four uniformly distributed single magnetic dipole units, with a strict 90° azimuth interval between each unit; the second ring array consists of eight units, with a precise 45° angular interval between units. This unique arrangement was derived through mathematical optimization calculations, where the first ring of units rotates as a whole by 14° (∠a) relative to the spherical conformal metal ground plane 1, and the second ring of units rotates as a whole by 28° (∠b), forming a specific spatial phase relationship. Full-wave electromagnetic simulation verified that this arrangement scheme achieves an optimal unit spacing of 26.8 mm (approximately 0.5λ) at a working frequency of 5.6 GHz. This key parameter design satisfies both the array radiation performance requirements and ensures structural compactness.

[0062] like Figure 8 As shown, specifically, through this precise geometric arrangement, the isolation between radiating elements in the same layer is controlled below -15dB, while the isolation between elements in different layers is below -25dB, significantly improving the overall radiation efficiency of the array. Measured data show that this arrangement enables the array to achieve a vertical polarization gain of 13.64dB in the Z-axis 0° direction, while maintaining a 7dB gain beamwidth of 32°, perfectly meeting the technical requirements of airborne communication systems for top-air coverage.

[0063] like Figure 2 As shown, the tabletop is made of the same copper material as the spherical conformal metal floor 1, and is long. = 40mm, width = 20mm. Due to the special characteristics of the spherical conformal metal floor 1, the length of the metal reflector 3 is always 20mm. = 40mm. Specifically, the width of the first ring of the metal reflector platform... = 19.70mm, the length of the countertop edge from the conformal floor. = 18mm; width of the second ring of metal reflector surface = 20mm , The length of the distance from the edge of the table to the spherical conformal metal floor 1 = 12.25mm.

[0064] The parallelism between the metal reflector platform 3 and the horizontal radiation section of the single magnetic dipole is controlled to ensure that they maintain a strict parallel relationship. For example... Figure 6 and Figure 10As shown in the diagram, the vertical polarization gain of the horizontally placed single magnetic dipole antenna element is maximized at 54°. Therefore, the metal reflector 3 is installed at a 54° angle relative to the horizontal ground, and this angle has been verified by full-wave electromagnetic simulation as the optimal direction for maximizing vertical polarization gain. The circular opening in the center is used to accommodate the coupling feed probe.

[0065] The antenna element feed phase setting of this invention employs a spatial current in-phase superposition and path difference compensation mechanism to achieve precise beamforming through accurate electromagnetic field calculations. As shown in Table 2, this system implements differentiated phase compensation based on the geometric characteristics of the dual-layer array: First, for opposing elements in each ring (such as the 0° and 180° elements in the first ring), the feed phase difference is precisely controlled to 180°, enabling the spatial currents of the elements to be superimposed in phase, ensuring that the radiated beams of each element can accurately point to the 0° direction of the Z-axis; Second, due to the existence of a path difference between the first ring (4 elements) and the second ring (8 elements), The height difference, according to electromagnetic wave propagation theory, results in a phase difference due to the path difference. The specific calculation formula is as follows:

[0066]

[0067] in c It's the speed of light. It refers to the frequency, here 5.6GHz, and the path difference. d = =12.2mm, calculated phase difference It is 82°.

[0068] Specifically, It is the vertical height difference between the horizontal radiating segments of the first and second rings of the single magnetic dipole antenna element (also the path difference between the vertical radiation of the first and second rings of the antenna array), and therefore is equivalent to the formula above. d That is, path difference.

[0069] like Figure 9 The radiation pattern test results shown indicate that a vertical polarization gain of 13.64 dB was achieved in the 0° Z-axis direction, and a 7 dB gain beamwidth of 32° was achieved. These performance indicators fully meet the requirements of the airborne communication system, especially ensuring the stability of the communication link when the aircraft is flying above the ground monitoring station.

[0070] All dimensions in this embodiment are shown in Table 1.

[0071] Table 1

[0072]

[0073] Table 2

[0074]

[0075] The corresponding positions of phases ①-⑫ are as follows: Figure 1 As shown in (c).

[0076] In summary, the antenna structure provided by the embodiments of the present invention successfully overcomes the inherent defects of vertically polarized antennas through spherical conformal design and precise phase compensation mechanism. Specifically, the present invention employs a collaborative design of tilted single magnetic dipole units and a metal reflector platform, effectively filling the radiation null in the Z-axis 0° direction through precise path difference compensation while maintaining vertical polarization characteristics. This conformal array structure not only solves the communication coverage problem in the overhead blind zone of aircraft but also adapts to various complex flight conditions, providing a reliable technical solution for next-generation aviation communication systems.

[0077] Based on the antenna structure provided in the embodiments of the present invention and without departing from the purpose of the present invention, those skilled in the art are capable of optimizing some of the above-mentioned design parameters according to different scenarios and needs, and are not limited to the size parameters provided in Table 1.

[0078] Furthermore, although the usage scenario provided by the embodiments of the present invention is based on aircraft communication, those skilled in the art should understand that the antenna structure of the present invention can also be applied in other scenarios, such as drones or other aircraft.

[0079] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0080] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. An antenna, characterized in that, include: Spherical conformal metal floor, conformally matched to the surface of the mounting carrier; And multiple single magnetic dipole units arranged in a ring array on the surface of the spherical conformal metal floor; The single magnetic dipole unit includes a metal reflector, a feed probe, and a bent metal radiating arm. The metal reflector is embedded in the surface of the spherical conformal metal floor and is inclined at 54°±0.5° relative to the horizontal ground. The bent metal radiating arm includes a vertical feeding section, a horizontal radiating section, and a grounding section; The grounding section is connected to the metal reflector surface, the vertical feed section is parallel to the grounding section, and the horizontal radiation section is connected between the vertical feed section and the grounding section. One end of the feed probe passes through the metal reflector and connects to the vertical feed section, while the other end is connected to the feed network.

2. The antenna according to claim 1, characterized in that, The metal reflector surface has an opening or groove in the middle to accommodate the feed probe.

3. The antenna according to claim 1, characterized in that, The bent metal radiating arm, the spherical conformal metal floor, and the metal reflector are all made of copper.

4. The antenna according to claim 1, characterized in that, The annular arrangement of single magnetic dipole units includes two sets of single magnetic dipole units arranged in circular arrays. The inner set of single magnetic dipole units has 4 units, and the outer set has 8 units. The line connecting the midpoint of the horizontal radiation segment of the inner ring to the center of the spherical conformal metal ground plane makes an angle of 14 degrees with the Z-axis. The line connecting the midpoint of the horizontal radiation segment of the outer ring to the center of the spherical conformal metal ground plane makes an angle of 28 degrees with the Z-axis.

5. The antenna according to claim 4, characterized in that, The spacing between single magnetic dipole units is half the wavelength corresponding to the operating frequency.

6. The antenna according to claim 4, characterized in that, There is a height difference between the horizontal radiation sections of the single magnetic dipole units in the inner and outer rings.

7. A method for blind spot control of a broadband vertically polarized antenna, comprising the following steps: By calculating the path difference in the Z-axis direction between the inner and outer single magnetic dipole units of the antenna as described in any one of claims 4 to 6, and determining the required phase compensation value accordingly, the electromagnetic waves radiated by the two ring units are made to be superimposed in phase in space by adjusting the feed network, thereby accurately concentrating the maximum vertical polarization gain in the +Z-axis direction.

8. The broadband vertical polarization antenna blind spot compensation control method according to claim 7, characterized in that, The phase difference caused by the path difference is The specific calculation formula is as follows: in c It's the speed of light. It's frequency. d This is the path difference.

9. An airborne communication system comprising the antenna as described in any one of claims 1 to 6.

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