Helical circularly polarized satellite communication antenna, antenna array and unmanned aerial vehicle

Abstract

The application relates to the technical field of antennas and discloses a spiral circularly polarized satellite communication antenna, an antenna array and a UAV, which comprises a feed medium substrate, a metal ground plate is arranged on the first end face of the feed medium substrate, a dumbbell-shaped slot coupling structure is etched on the metal ground plate, a feed network input piece and a feed network output piece are arranged at intervals on the second end face opposite to the first end face; the feed network output piece is located in the middle part of the feed medium substrate, and the projection of the feed network output piece on the plane of the metal ground plate is perpendicular to the slot coupling structure; and a flexible medium substrate cylinder is vertically connected to the metal ground plate, metal radiation arms are spirally arranged on the outer surface of the flexible medium substrate cylinder, and the metal radiation arms are connected to the opposite two side end parts of the feed network output piece through metal connecting pieces. On the basis of providing stable circularly polarized radiation performance, the antenna structure is miniaturized by effectively simplifying the feed structure.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a spiral circularly polarized satellite communication antenna, antenna array, and unmanned aerial vehicle (UAV). Background Technology

[0002] Spiral antennas are widely used in satellite communications and other fields due to their excellent beam characteristics and axial ratio performance, especially quad-spiral antennas which can achieve relatively stable circular polarization radiation. However, to achieve circular polarization radiation, quad-spiral antennas usually rely on complex power divider phase shifting networks to provide four excitation signals with equal amplitude and sequentially 90° phase differences, resulting in a relatively complex feeding structure.

[0003] In L-band applications, achieving the aforementioned orthogonal phase relationship typically requires the use of delay lines or hybrid coupler networks. These structures not only occupy significant physical space, but also substantially increase the footprint of the feed dielectric substrate, making them unsuitable for the installation requirements of miniaturized platforms such as drones.

[0004] Furthermore, traditional feeding methods typically require complex external coaxial cable assemblies to achieve impedance transformation and balanced feeding. This further increases the overall size and profile height of the antenna, while also introducing additional energy loss and structural complexity, thus limiting the integrated application of the antenna on miniaturized UAV platforms to some extent. Summary of the Invention

[0005] This invention provides a helical circularly polarized satellite communication antenna, antenna array, and UAV to solve the technical problem of complex antenna feeding structures in the prior art.

[0006] In a first aspect, to solve the aforementioned technical problems, the present invention provides a helical circularly polarized satellite communication antenna, comprising a feed dielectric substrate, a metal ground plane disposed on a first end face of the feed dielectric substrate, a dumbbell-shaped slot coupling structure etched on the metal ground plane, and a feed network input and a feed network output disposed at intervals on a second end face opposite to the first end face; the feed network output is located in the middle of the feed dielectric substrate, and the projection of the feed network output onto the plane of the metal ground plane is perpendicular to the slot coupling structure; and A flexible dielectric substrate cylinder is vertically connected to the metal floor. A metal radiating arm is spirally wound around the outer surface of the flexible dielectric substrate cylinder, and the metal radiating arm is connected to the opposite ends of the power supply network output component through a metal connector.

[0007] In some embodiments, the slot coupling structure includes a rectangular connecting portion and circular ends symmetrically disposed at opposite ends of the connecting portion.

[0008] In some embodiments, the metal connector includes a metal post and a trapezoidal metal patch; the bottom of the metal post is vertically connected to the power supply network output, the top of the metal post is connected to the first bottom edge of the metal patch, and the second bottom edge of the metal patch is connected to the metal radiating arm; the first bottom edge is parallel to the second bottom edge, and the length of the first bottom edge is less than the length of the second bottom edge.

[0009] In some embodiments, the metal pillar is cylindrical, a cylindrical groove is formed on the first end face of the feeding dielectric substrate, a through hole coaxial with the groove is formed on the metal floor, and the metal pillar passes through the through hole and is adapted to the groove.

[0010] In some embodiments, the power supply network input includes a microstrip transmission line and a patch circle, wherein the microstrip transmission line and the patch circle are integrally formed; the microstrip transmission line is parallel to the power supply network output; and the patch circle overlaps with the projection portion of the slot coupling structure on the plane of the power supply dielectric substrate.

[0011] In some embodiments, the system further includes a first carbon-based cylindrical tube embedded within the flexible dielectric substrate tube, a second carbon-based cylindrical tube coaxially nested inside the first carbon-based cylindrical tube, and a flexible dielectric substrate surrounding the outer surface of the second carbon-based cylindrical tube.

[0012] In some embodiments, the flexible dielectric substrate has a plurality of symmetrical guide bands on the surface facing the first carbon-based cylinder, and the plurality of guide bands are perpendicular to the feed dielectric substrate.

[0013] In some embodiments, the ratio of the width of the guide band to the width of the metal radiating arm is 1:1.

[0014] In a second aspect, the present invention also provides an antenna array comprising four spiral circularly polarized satellite communication antennas as described in any of the embodiments of the first aspect.

[0015] Thirdly, the present invention also provides an unmanned aerial vehicle (UAV) including the antenna array of the aforementioned second aspect embodiment, and further including a wing, the top of which is connected to the second end face of the feed dielectric substrate.

[0016] Compared with existing technologies, the spiral circularly polarized satellite communication antenna of this invention has the following advantages: In this embodiment, a dumbbell-shaped slot coupling structure is etched onto a metal floor on the first end face of the feeding dielectric substrate. This allows the electromagnetic energy generated by the feed network output to be efficiently coupled to a double-helical metal radiating arm wound around the outer surface of the flexible dielectric substrate cylinder via electromagnetic coupling, thus replacing the complex feeding method that relies on a power-dividing phase-shifting network to achieve multi-path orthogonal excitation. Simultaneously, the feed network output is arranged in the middle of the feeding dielectric substrate, and its projection onto the plane of the metal floor is perpendicular to the slot coupling structure. This facilitates the formation of a stable and symmetrical field distribution in space, enabling the electromagnetic field coupled through the slot to excite a pair of differential currents with a 180° phase difference on the surface of the flexible dielectric substrate cylinder. Furthermore, under this differential excitation, the double-helical metal radiating arm forms a gradually changing current distribution along the circumference, thereby synthesizing a stable rotating electric field in space and achieving circularly polarized radiation. Due to the synergistic effect of the differential excitation and slot coupling structure, there is no need to set up a traditional four-way equal-amplitude orthogonal feed power divider / phase shifter network, avoiding the introduction of delay lines, hybrid couplers, or external baluns, thereby reducing the complexity of the feed network and reducing insertion loss. Simultaneously, the feed network output, feed network input, and radiating structure (a metal radiating arm wound in a double helix on the outer surface of the flexible dielectric substrate cylinder) are integrated through the feed dielectric substrate and its spatial coupling, reducing the feed path length and additional structural dimensions, making the overall structure more compact. Therefore, this invention achieves effective simplification of the feed structure and miniaturization of the overall antenna while ensuring the stability of circularly polarized radiation performance. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the flexible dielectric substrate tube in the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the feed dielectric substrate in the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention; Figure 4 This is a partially enlarged view of the first end face of the feed dielectric substrate in the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the first end face of the feed dielectric substrate in the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention; Figure 6 This is a side view of the flexible dielectric substrate cylinder in the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention. Figure 7This is a simulation result diagram of the return loss of the spiral circularly polarized satellite communication antenna provided in the embodiment of the present invention; Figure 8 This is a simulation result diagram of the gain of the spiral circularly polarized satellite communication antenna provided in an embodiment of the present invention; Figure 9 This is the E-plane radiation pattern of the spiral circularly polarized satellite communication antenna provided in this embodiment of the invention at the center frequency. Figure 10 This is the H-plane radiation pattern of the spiral circularly polarized satellite communication antenna at the center frequency point provided in this embodiment of the invention.

[0018] In the figure, 100 is the power supply dielectric substrate; 110 is the metal ground plane; 111 is the slot coupling structure; 111a is the connector; 111b is the circular end; 112 is the through hole; 120 is the power supply network input; 121 is the microstrip transmission line; 122 is the patch circle; 130 is the power supply network output; 140 is the second end face; 200 is the flexible dielectric substrate cylinder; 210 is the metal radiating arm; 300 is the metal connector; 310 is the metal pillar; 320 is the metal patch; 400 is the first carbon-based cylindrical cylinder; 500 is the second carbon-based cylindrical cylinder; 510 is the flexible dielectric substrate; and 511 is the guide strip. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. 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.

[0020] In the description of this invention, it should be noted that the directional terms such as "center", "upper", "lower", "inner", and "outer" indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limiting the specific protection scope of this invention.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the use of "first" and "second" to define a feature may explicitly or implicitly include one or more of that feature, and in the description of this invention, "at least" means one or more, unless otherwise explicitly specified.

[0022] In this invention, unless otherwise explicitly specified and limited, the terms "assembly," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection; they can refer to a direct connection or a connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] See again Figures 1 to 6 This invention provides a spiral circularly polarized satellite communication antenna, comprising a feed dielectric substrate 100, a metal ground plane 110 disposed on a first end face (not shown in the figure) of the feed dielectric substrate 100, a dumbbell-shaped slot coupling structure 111 etched on the metal ground plane 110, and a feed network input component 120 and a feed network output component 130 disposed at intervals on a second end face 140 opposite to the first end face; the feed network output component 130 is located in the middle of the feed dielectric substrate 100, and the projection of the feed network output component 130 on the plane of the metal ground plane 110 is perpendicular to the slot coupling structure 111; and a flexible dielectric substrate cylinder 200, which is vertically connected to the metal ground plane 110, and a metal radiating arm 210 is wound in a double spiral on the outer surface of the flexible dielectric substrate cylinder 200, and the metal radiating arm 210 is connected to the opposite two ends of the feed network output component 130 through a metal connector 300.

[0024] In this embodiment, the feed dielectric substrate 100 is made of a low-loss microwave dielectric material, preferably F4B material (F4B material, polytetrafluoroethylene glass fiber composite board), with a dielectric constant of 3.5 ± 0.2 and a dielectric thickness of 1.5 mm ± 0.1 mm, to balance structural strength and electromagnetic performance in the 1.2 GHz to 1.8 GHz frequency band. The feed dielectric substrate 100 has an overall circular structure with a radius preferably of 25 mm ± 0.5 mm, thereby achieving miniaturization and weight reduction of the structure while ensuring radiation performance.

[0025] Understandably, with Figure 1 Taking the shown perspective as an example, the first end face (not shown in the figure) is the upper surface of the feed dielectric substrate 100, and the second end face 140 opposite to the first end face is the lower surface of the feed dielectric substrate 100. The metal ground plane 110 is a circular structure with the same diameter as the feed dielectric substrate, and it covers the first end face of the feed dielectric substrate.

[0026] Specifically, a metal ground plane 110 is disposed on the first end face of the feed dielectric substrate 100. The metal ground plane 110 adopts a full-surface copper-clad structure with a copper layer thickness of 0.035 mm and a surface conductivity preferably of 5.8 × 10⁻⁶ mm. Siemens per meter (S / m). Dumbbell-shaped slot coupling structures 111 are formed on the metal floor 110 by a chemical etching process.

[0027] Furthermore, both the power supply network input device 120 and the power supply network output device 130 are disposed on the second end face 140 of the power supply dielectric substrate 100, and are spaced apart from each other. The power supply network input device 120 includes a microstrip transmission line 121 and a patch circle 122, which are integrally formed. The characteristic impedance of the microstrip transmission line 121 is 50 ohms (Ω), and the linewidth is preferably 3.0 mm ± 0.2 mm. The radius of the patch circle 122 is preferably 3.6 mm ± 0.1 mm. The patch circle 122 overlaps spatially with the projection portion of the slot coupling structure 111 in the thickness direction of the power supply dielectric substrate 100 to achieve efficient coupling and transmission of electromagnetic energy.

[0028] The output device 130 of the feed network uses the same microstrip transmission line 121 as the input device 120 of the feed network, with a characteristic impedance of 50Ω, to achieve impedance continuity between the input and output and reduce reflection loss. The projection of the microstrip output line on the feed dielectric substrate 100 is arranged in an approximately "+" shape with the dumbbell-shaped slot coupling structure 111 (or, the projection direction of the feed network output device 130 on the plane of the metal ground plate 110 is perpendicular to the long axis of the slot coupling structure 111), bridging the central slit and the extended regions at both ends of the slot. The dumbbell-shaped slot coupling structure 111 is symmetrical about its central axis. Under the excitation of the input signal, electric field distributions with equal amplitude and opposite directions are formed on both sides, corresponding to the formation of an odd-mode current distribution with opposite phase within the slot structure. The microstrip output line couples this odd-mode current to feed signals with equal amplitude and opposite phase into the double-arm spiral structure, thereby achieving differential excitation. Meanwhile, since the geometry and symmetrical layout of the dumbbell-shaped slit remain consistent in the 1.2GHz to 1.8GHz frequency band, its coupling coefficient and phase response change little with frequency. Therefore, the output can stably provide differential signals with equal amplitude and a phase difference of about 180°, thus meeting the circular polarization excitation requirements of the double-arm spiral radiation structure.

[0029] The projection direction of the feed network output component 130 onto the plane of the metal floor 110 is perpendicular to the long axis of the slot coupling structure 111. This orthogonal arrangement effectively suppresses the coupling of undesired modes, enhances the purity of the differential signal, reduces crosstalk between the feed network and the radiating structure, and improves the overall radiation efficiency.

[0030] Specifically, such as Figure 1 , Figure 2As shown, the flexible dielectric substrate cylinder 200 is vertically fixed to the metal ground plane 110 on the side facing away from the feed dielectric substrate 100. The flexible dielectric substrate cylinder 200 is made of a flexible dielectric material, preferably polyimide, with a dielectric constant of 2.15 ± 0.05. The flexible dielectric substrate 510 is formed into a cylindrical structure by winding, and its diameter d is set between 0.18 and 0.25 times the wavelength of the antenna operating frequency band to excite radiated axial modes.

[0031] In a preferred embodiment, the thickness of the flexible dielectric substrate cylinder 200 is set to 0.2mm±0.05mm, the diameter is set to 19.6mm±0.4mm, and the height is set to 93mm±3mm.

[0032] Specifically, the metal radiating arms 210 are a double-arm structure, consisting of two arms, symmetrically wound in a double helix along the outer surface of the flexible dielectric substrate cylinder 200. Each metal radiating arm 210 is made of copper foil material with a thickness of 0.035 mm and a width of 3.2 mm ± 0.2 mm. The two metal radiating arms 210 are spatially symmetrically distributed, and the helical pitch is optimized according to the operating frequency band, so that the length of the metal radiating arm 210 is approximately 3 / 4 of the wavelength corresponding to the operating frequency, thereby exciting axial mode radiation.

[0033] The metal connector 300 is used to realize the electrical connection and impedance transition between the feed network output component 130 and the metal radiating arm 210. The starting ends of the metal radiating arm 210 are connected to the two ends of the feed network output component 130 respectively through the metal connector 300, and the ends are open-circuit structures. Through differential feeding, the two metal radiating arms 210 respectively receive signals with a phase difference of 180°, forming a rotating current distribution in space, thereby generating circularly polarized electromagnetic wave radiation.

[0034] In this embodiment, the feed dielectric substrate 100 serves as the core carrier structure of the antenna. A metal ground plane 110 is provided on its first end face. A dumbbell-shaped slot coupling structure 111 is etched on the metal ground plane 110 to effectively couple the signal from the feed network output component 130 to the metal ground plane 110. The feed network output component 130 is located in the middle of the feed dielectric substrate 100. Its projection onto the plane of the metal ground plane 110 is perpendicular to the slot coupling structure 111, ensuring that the metal radiating arms 210 on both sides receive voltage signals with consistent amplitude. This achieves highly symmetrical circular polarization excitation, enhancing the stability and polarization purity of the radiation. The flexible dielectric substrate cylinder 200 of the antenna is vertically connected to the end face of the metal ground plane 110 facing away from the feed dielectric substrate 100. A double-helix metal radiating arm 210 is wound around its outer surface and connected to the opposite ends of the feed network output component 130 via a metal connector 300. This structure can evenly distribute the power output from the feed network to the double-helix radiating arms, achieving circularly polarized radiation. Simultaneously, the use of a flexible dielectric allows the helical arms to fit tightly against the substrate surface, further reducing the overall antenna size. Thus, the antenna of this invention not only provides stable circularly polarized radiation performance, ensuring the reliability of satellite communication links, but also simplifies traditional feeding methods through slot coupling and a flexible helical structure, thereby achieving miniaturization and weight reduction of the antenna structure, facilitating deployment in space-constrained environments such as satellites or mobile terminals.

[0035] In one embodiment, such as Figure 3 As shown, the slot coupling structure 111 includes a rectangular connecting part 111a and circular ends 111b symmetrically arranged at opposite ends of the connecting part 111a.

[0036] In this embodiment, the slot coupling structure 111 includes a rectangular connecting portion 111a located in the middle of the feed dielectric substrate 100 and circular end portions 111b symmetrically disposed at both ends of the connecting portion 111a. The rectangular connecting portion 111a preferably has a length of 28.8 mm ± 0.1 mm and a width of 1.2 mm ± 0.1 mm, while the circular end portions 111b have a radius of 1.9 mm ± 0.1 mm. Through this strictly symmetrical geometric structure, electric field distribution boundaries with equal amplitude and opposite polarity are formed at both ends of the slot, thereby providing a physical basis for the generation of differential signals.

[0037] Specifically, when a signal is injected into the slot coupling structure 111 at the output of the power supply network, the electromagnetic coupling generated in the slot is uniformly distributed along both sides because the rectangular connection portion 111a of the slot is located in the middle of the power supply dielectric substrate 100 and the circular ends 111b at both ends are strictly symmetrical. The rectangular connection portion 111a serves as the main transmission channel, ensuring that the signal amplitude remains consistent when it is shunt at both ends. At the same time, due to the geometric symmetry at both ends of the slot, the current flows in opposite directions at both ends, thereby forming electric fields of opposite polarities near the circular ends 111b.

[0038] The electric field distribution boundary follows electromagnetic boundary conditions: the metal ground planes 110 at both ends of the slot form a mirror symmetry plane, ensuring that the electric field amplitude is equal and the direction is opposite at both ends, thus guaranteeing the formation of an ideal differential signal at the output. The amplitude consistency and 180° phase difference of the differential signal provide balanced excitation for the helical radiating arm, achieving stable circularly polarized radiation. Simultaneously, by adjusting the geometric dimensions (e.g., the length and width of the connection 111a and the radius of the circular end 111b), this characteristic can be ensured to remain stable within a wide bandwidth of 1518 MHz to 1675 MHz. Thus, the requirements for broadband differential signals are met while reducing the dependence on the complexity of the feed structure, providing a physical basis for antenna miniaturization and high performance.

[0039] It should be noted that in a specific application scenario, 1518MHz-1675MHz is the operating frequency band required for satellite communication.

[0040] In one embodiment, such as Figure 1 , Figure 2 and Figure 3 As shown, the metal connector 300 includes a metal post 310 and a trapezoidal metal patch 320; the bottom of the metal post 310 is vertically connected to the power supply network output component 130, the top of the metal post 310 is connected to the first bottom edge of the metal patch 320, and the second bottom edge of the metal patch 320 is connected to the metal radiating arm 210; the first bottom edge is parallel to the second bottom edge, and the length of the first bottom edge is less than the length of the second bottom edge. Figure 2 and Figure 6 As shown, the length of the first base is The length of the second base is ,have .

[0041] The metal pillar 310 is cylindrical, and a cylindrical groove is formed on the first end face of the feeding dielectric substrate 100. A through hole 112 coaxial with the groove is formed on the metal floor 110, and the metal pillar 310 passes through the through hole 112 and is adapted to the groove.

[0042] In this embodiment, the metal connector 300 includes a metal post 310 and a trapezoidal metal patch 320. The metal post 310 has a cylindrical structure with a radius preferably of 0.6 mm ± 0.1 mm. The bottom of the metal post 310 is vertically welded to the end of the power supply network output component 130, and the top is connected to the first bottom edge of the trapezoidal metal patch 320. A cylindrical groove is formed at a corresponding position on the power supply substrate 100, and a coaxial through hole 112 is formed at a corresponding position on the metal floor 110 (the diameter of the through hole 112 can be set according to actual needs, for example, 1.4 mm ± 0.1 mm). The metal post 310 passes through the through hole 112 and is electrically connected to the groove wall, thereby forming a stable vertical conduction path.

[0043] A trapezoidal metal patch 320 is used to achieve impedance gradient matching. The first bottom edge of the metal patch 320 is connected to the top of the metal pillar 310, and the second bottom edge is connected to the end of the metal radiating arm 210. The length of the first bottom edge is preferably 0.6mm ± 0.2mm, the length of the second bottom edge is preferably 2.0mm ± 0.1mm, and the height is 2.0mm ± 0.1mm. The first and second bottom edges are parallel to each other, and the length of the first bottom edge is less than the length of the second bottom edge. Through the trapezoidal gradient structure, the impedance change from the microstrip output line to the spiral radiating arm is smoother, thereby reducing reflection loss and widening the operating bandwidth.

[0044] The metal pillars 310 and trapezoidal metal patches 320 serve as power feeding intermediates, with their number corresponding to the number of metal radiating arms 210 in a 1:1 ratio. Each radiating arm corresponds to a set of metal pillars 310 and metal patches 320, ensuring that each radiating arm receives an independent and consistent excitation current. Simultaneously, the grooves on the power feeding dielectric substrate 100 and the through holes 112 on the metal ground plane 110 are used for fixing and conducting the metal pillars 310, with their number also corresponding to the number of metal pillars 310 in a 1:1 ratio, ensuring that each metal pillar 310 can be accurately and securely inserted into the grooves and through holes 112. Thus, each metal radiating arm 210 can obtain a differential signal stably transmitted through the metal pillars 310 and trapezoidal metal patches 320, achieving current amplitude balance and phase consistency, thereby ensuring the stable circular polarization performance of the double-helix radiating structure. Furthermore, this structural design helps simplify the power feeding network layout, avoids signal interference and uneven coupling, and improves matching efficiency over a wide bandwidth.

[0045] Specifically, the differential current output by the power supply network output device 130 is first injected vertically into the metal pillar 310. Since the metal pillar 310 has a cylindrical structure and passes through the through-hole 112 and the groove in the power supply dielectric substrate 100, the current can be conducted upward in an approximately axisymmetric manner, thereby reducing parasitic inductance and discontinuity effects during current transmission and improving the stability of the power supply. At the same time, the through-hole 112 on the metal ground plate 110 and the groove on the power supply dielectric substrate 100 are coaxially arranged, so that the metal pillar 310 and the surrounding medium form a stable electromagnetic boundary environment, suppressing the generation of stray modes.

[0046] When current is transmitted to the metal patch 320, the trapezoidal structure of the metal patch 320, with a gradual transition from a shorter first base to a longer second base, causes the current distribution to gradually expand from a concentrated state, achieving gradual impedance matching. This gradual structure effectively reduces the impedance abrupt change between the output of the power supply network and the metal radiating arm 210, reduces reflection loss, and thus improves energy transmission efficiency.

[0047] Furthermore, the current, after being broadened by the trapezoidal metal patch 320, is uniformly coupled to the metal radiating arm 210, so that the two radiating arms obtain excitation currents with consistent amplitudes and maintain the phase relationship required for differential feeding, thereby ensuring the stable circular polarization radiation of the double helix structure.

[0048] Thus, through the synergistic effect of the metal pillar 310 and the trapezoidal metal patch 320, not only is an efficient transition from planar feeding to a three-dimensional spiral radiation structure achieved, but also the matching performance and radiation efficiency in a wide bandwidth are improved through impedance gradient and uniform current distribution, while reducing structural complexity and facilitating antenna miniaturization.

[0049] In one embodiment, such as Figure 2 , Figure 4 and Figure 6 As shown, the height of the flexible dielectric substrate cylinder 200 is h, and the lateral dimension of the metal radiating arm 210 is... The height of the metal patch 320 is The length of the metal radiating wall 210 is equal to The radius of the metal pillar 310 is R, and the dielectric constant of the feed dielectric substrate 100 is... The characteristic impedance of the feed dielectric substrate 100 is The radius of the through hole is D, and we have: .

[0050] In one specific embodiment, the lateral dimension of the metal radiating wall 210 l =60mm, the height h of the flexible dielectric substrate cylinder 200 is 93mm, and the height of the metal patch 320 is =2mm, the length of the metal radiating wall 210 is =109mm.

[0051] In one embodiment, such as Figure 3 As shown, the power supply network input device 120 includes a microstrip transmission line 121 and a patch circle 122, with the microstrip transmission line 121 and the patch circle 122 integrally formed; the microstrip transmission line 121 is parallel to the power supply network output device 130; the patch circle 122 overlaps with the projection portion of the slot coupling structure 111 on the plane where the power supply dielectric substrate 100 is located.

[0052] In this embodiment, the feed network input 120 is disposed on the second end face 140 of the feed dielectric substrate 100, and is used to receive external radio frequency signals and transmit the signals to the slot coupling structure 111. The microstrip transmission line 121 and the patch circle 122 are formed by an integrated copper foil structure to form a continuous conductive structure. There are no solder joints or transition structures between them to ensure the continuity of the signal transmission path and low loss characteristics. The characteristic impedance of the microstrip transmission line 121 is 50Ω. The extension direction of the microstrip transmission line 121 is parallel to the extension direction of the feed network output 130, so that the feed network input 120 and the feed network output 130 are arranged side by side on the second end face 140, thereby maintaining the compact layout of the feed network. The projection of the patch circle 122 in the thickness direction of the feed dielectric substrate 100 overlaps with the projection of the slot coupling structure 111, so that the input signal is effectively injected into the slot structure by electromagnetic coupling to achieve a balance between coupling strength and bandwidth.

[0053] Specifically, when the microstrip transmission line 121 transmits the differential or single-ended excitation signal to the patch circle 122, the projection of the patch circle 122 onto the plane of the metal ground plane 110 partially overlaps with the slot coupling structure 111. This allows the input signal to establish electromagnetic coupling within the slot through this overlapping area. This coupling is spatially symmetrically distributed along both ends of the slot, resulting in voltage signals of equal amplitude and opposite polarity, providing a stable differential input to the feed network output device 130. Thus, by utilizing the integrated structure of the microstrip transmission line 121 and the patch circle 122, efficient energy transmission from planar feed to slot coupling can be achieved, while ensuring uniform excitation current for the double-helix radiating arm, thereby achieving stable circularly polarized radiation.

[0054] In one embodiment, such as Figure 1 As shown, it also includes a first carbon-based cylindrical tube 400 embedded in the flexible dielectric substrate tube 200, a second carbon-based cylindrical tube 500 coaxially nested inside the first carbon-based cylindrical tube 400, and a flexible dielectric substrate 510 surrounding the outer surface of the second carbon-based cylindrical tube 500.

[0055] In this embodiment, the first carbon-based cylindrical tube 400 is a cylindrical structure made of conductive carbon fiber material, possessing high strength and excellent electromagnetic shielding performance. The first carbon-based cylindrical tube 400 serves as a support for the flexible dielectric substrate tube 200, and is at the same height as the flexible dielectric substrate tube 200, with the flexible dielectric substrate tube 200 tightly fitted onto the first carbon-based cylindrical tube 400. The bottom of the first carbon-based cylindrical tube 400 is fixed to the metal ground plate 110 by mechanical pressing or annular adhesive, ensuring stable structural support and electromagnetic shielding isolation between the first carbon-based cylindrical tube 400 and the flexible dielectric substrate tube 200. Preferably, there is one first carbon-based cylindrical tube 400 to provide the basic support structure for the antenna radiating cavity, while also providing uniform electromagnetic boundary conditions for the internal differential feed and helical radiating arm, which is beneficial for stabilizing circular polarization performance and reducing high-frequency parasitic modes.

[0056] Specifically, the second carbon-based cylindrical tube 500 is coaxially nested inside the first carbon-based cylindrical tube 400. It is also cylindrical and made of conductive carbon fiber material. Its outer diameter is slightly smaller than the inner diameter of the first carbon-based cylindrical tube 400 by 10 mm, creating a gap to facilitate medium regulation and heat dissipation. The second carbon-based cylindrical tube 500 is axially fixed inside the first carbon-based cylindrical tube 400 and supported by an annular insulating pad or adhesive, ensuring that the second carbon-based cylindrical tube 500 maintains coaxial stability while avoiding direct electrical contact with the first carbon-based cylindrical tube 400.

[0057] In one embodiment, such as Figure 1 As shown, the flexible dielectric substrate 510 has a plurality of symmetrical guide strips 511 on its surface facing the first carbon-based cylindrical tube 400, and the plurality of guide strips 511 are perpendicular to the power-feeding dielectric substrate 100.

[0058] In this embodiment, a flexible dielectric substrate 510 surrounds the outer surface of the second carbon-based cylindrical tube 500. The flexible dielectric substrate 510 can be made of polyimide material, and its thickness is preferably 0.1 to 0.3 mm to provide the necessary dielectric support.

[0059] A plurality of symmetrical guide strips 511 are disposed on the surface of the flexible dielectric substrate 510 facing the first carbon-based cylindrical tube 400. The guide strips 511 are symmetrically distributed along the axial direction of the first carbon-based cylindrical tube 400, and each guide strip 511 is perpendicular to the feeding dielectric substrate 100. The guide strips 511 are made of copper foil material, preferably with a thickness of 0.035 mm, a length approximately three-quarters of the height of the first carbon-based cylindrical tube 400, and a width consistent with the width of the metal radiating arm 210. The guide strips 511 are fixed to the surface of the flexible dielectric substrate 510 by annular bonding or hot pressing to form a continuous conductive path.

[0060] In one specific embodiment, the number of guide strips 511 is set to 2, and the 2 guide strips 511 are symmetrically arranged on the surface of the flexible dielectric substrate 510 facing the first carbon-based cylindrical tube 400.

[0061] In one embodiment, the ratio of the width of the guide band 511 to the width of the metal radiating arm 210 is 1:1.

[0062] In this embodiment, the width of each guide strip 511 is the same as the width of the corresponding spiral metal radiating arm 210, preferably 2 mm ± 0.1 mm, so that the guide strip 511 provides sufficient mechanical support and guidance for the spiral radiating arm, while avoiding the introduction of additional parasitic capacitance or inductance, thereby keeping the electrical characteristics of the radiating arm undisturbed.

[0063] The built-in guide band 511, acting as a passive parasitic radiation unit, undergoes near-field electromagnetic coupling with the outer metal radiating arm 210 in space. This synergistic design of "inner parasitic guidance and outer main helical radiation" fully utilizes the unused space inside the flexible dielectric substrate cylinder 200, increasing the maximum circular polarization radiation gain from the conventional 2.8 dB to approximately 4 dB without significantly increasing the external physical dimensions of the flexible dielectric substrate cylinder 200. This structure greatly enhances the margin and stability of the communication link between the UAV and high / low orbit satellites under complex attitudes.

[0064] This invention also provides an antenna array comprising four spiral circularly polarized satellite communication antennas as described in the foregoing embodiments.

[0065] This invention also provides a drone, which includes the antenna array in the foregoing embodiments, and also includes a wing, the top of which is connected to the second end face 140 of the feed dielectric substrate 100.

[0066] In this embodiment, four helical circularly polarized satellite communication antennas are fixedly mounted on the four wings of the UAV (specifically, the top of the wings is connected to the second end face 140 of the feed dielectric substrate 100). The four wings are symmetrically distributed along the UAV body, thus forming a distributed array structure in space. Each helical circularly polarized satellite communication antenna has an independent radiation direction and coverage area, and a multiple-input multiple-output communication system is constructed through spatial diversity.

[0067] Specifically, the helical circularly polarized satellite communication antennas located at different wing positions form a coordinated coverage in both the vertical and horizontal directions, giving the antenna array near-omnidirectional radiation capability. The helical structure provides excellent axial radiation characteristics, while the circular polarization reduces the impact of attitude changes on the communication link. The spatial combination of the four antennas effectively compensates for the radiation blind spots of individual antennas in specific directions, thereby achieving continuous coverage of the UAV in both the circumferential and pitch directions.

[0068] Furthermore, during UAV flight, when the UAV undergoes pitch, roll, or yaw attitude changes, at least one or more helical circularly polarized satellite communication antennas can maintain an effective link connection with the satellite, thereby ensuring the continuity and stability of the communication signal. This array configuration not only improves the communication system's resistance to obstruction and link reliability but also enhances its communication robustness under complex flight attitudes, meeting the satellite communication needs of UAVs in dynamic environments.

[0069] It should be noted that the return loss, gain, and radiation pattern simulation results were obtained by simulating and optimizing the various structural parameters of the helical circularly polarized satellite communication antenna in this invention using electromagnetic simulation software (Computer Simulation Technology, CST). The accompanying drawings in the specification are relevant. Figure 7 The scattering parameter S11, also known as the input reflection coefficient, represents the ratio of the reflected signal to the input signal measured from the same port when the excitation signal is input from the port. Its absolute value in logarithmic form (i.e., |S11| in decibels) is used to characterize the impedance matching characteristics of the antenna. The scattering parameter S11 is a commonly used setting in this field and will not be elaborated further here.

[0070] In the attached diagram of the instruction manual Figure 8 In this context, Gain represents the maximum radiation gain of the antenna across the entire frequency band, measured in decibels (dB). Figure 9 and Figure 10 In this context, Gain represents the radiation pattern of the antenna on the E-plane (the plane where the electric field vector is parallel to the incident plane) and the H-plane (the plane where the magnetic field vector is parallel to the incident plane). The E-plane and the H-plane are perpendicular to each other, and together they characterize the omnidirectional radiation characteristics of the antenna in three-dimensional space. Figure 9 and Figure 10 The angular coordinates from “0” to “330” represent the azimuth angle in degrees (°), and the radial coordinates represent the gain value in decibels (dB).

[0071] like Figures 7 to 10As shown, simulation results indicate that the spiral circularly polarized satellite communication antenna of this invention exhibits a return loss of less than -10dB in the frequency range of 1.5GHz to 1.72GHz, demonstrating good impedance matching characteristics and meeting the requirements for wideband operation. Figure 8 As shown, the antenna gain exhibits a stable upward trend over a wide frequency range of 1.2 GHz to 1.9 GHz, reaching a peak of approximately 4.9 dB near 1.7 GHz. Compared to similar axial helical antennas, this represents a gain improvement of approximately 1 dB achieved through the inner flexible dielectric substrate and guide band structure. For details, please refer to [reference needed]. Figure 9 and Figure 10 ,Depend on Figure 9 and Figure 10 As can be seen, at the operating frequency of 1.67 GHz, both the E-plane and H-plane radiation patterns of the antenna exhibit good omnidirectional radiation characteristics. Although the maximum gain of the H-plane is slightly lower than that of the E-plane, the maximum radiation gain is approximately 4 dB, indicating that the antenna has uniform coverage capability in the horizontal plane. In summary, the spiral circularly polarized satellite communication antenna of this invention not only achieves wideband impedance matching and gain enhancement, but also possesses excellent omnidirectional circularly polarized radiation performance, effectively meeting the requirements of stable communication between UAVs and satellites under attitude changes such as pitch, roll, and yaw during flight.

[0072] The working process of this invention is as follows: In this embodiment, a dumbbell-shaped slot coupling structure 111 is etched on a metal ground plane 110 provided on the first end face of the feeding dielectric substrate 100. This allows the electromagnetic energy generated by the feeding network output device 130 to be efficiently coupled to the double-helical wound metal radiation arm 210 on the outer surface of the flexible dielectric substrate cylinder 200 via electromagnetic coupling, thereby replacing the complex feeding form that relies on a power-dividing phase-shifting network to achieve multi-path orthogonal excitation. Simultaneously, the feeding network output device 130 is arranged in the middle of the feeding dielectric substrate 100, and its projection on the plane of the metal ground plane 110 is perpendicular to the slot coupling structure 111. This facilitates the formation of a stable and symmetrical field distribution in space, enabling the electromagnetic field coupled via the slot to excite a pair of differential currents with a phase difference of 180° on the surface of the flexible dielectric substrate cylinder 200. Furthermore, under this differential excitation, the double-helical wound metal radiation arm 210 forms a current distribution that gradually changes circumferentially, thereby synthesizing a stable rotating electric field in space and achieving circularly polarized radiation. Due to the synergistic effect of the differential excitation and the slot coupling structure 111, there is no need to set up a traditional four-way equal-amplitude orthogonal feed power divider phase-shifting network, avoiding the introduction of delay lines, hybrid couplers, or external baluns, thereby reducing the complexity of the feed network and reducing insertion loss. Simultaneously, the feed network output component 130, the feed network input component 120, and the radiating structure (a metal radiating arm 210 wound in a double helix on the outer surface of the flexible dielectric substrate cylinder 200) are integrated through the feed dielectric substrate 100 and its spatial coupling, reducing the feed path length and additional structural dimensions, making the overall structure more compact. Therefore, this invention achieves effective simplification of the feed structure and miniaturization of the overall antenna while ensuring the stability of circularly polarized radiation performance.

[0073] In summary, this embodiment of the invention provides a spiral circularly polarized satellite communication antenna, which includes a feed dielectric substrate 100, a metal ground plane 110 disposed on a first end face of the feed dielectric substrate 100, a dumbbell-shaped slot coupling structure 111 etched on the metal ground plane 110, and a feed network input component 120 and a feed network output component 130 disposed at intervals on a second end face 140 opposite to the first end face; the feed network output component 130 is located in the middle of the feed dielectric substrate 100, and the projection of the feed network output component 130 on the plane of the metal ground plane 110 is perpendicular to the slot coupling structure 111; and a flexible dielectric substrate cylinder 200 is vertically connected to the end face of the metal ground plane 110 facing away from the feed dielectric substrate 100, and a metal radiating arm 210 is wound in a double spiral on the outer surface of the flexible dielectric substrate cylinder 200, and the metal radiating arm 210 is connected to the opposite two ends of the feed network output component 130 through a metal connector 300. This invention achieves miniaturization of the antenna structure by effectively simplifying the feeding structure, while providing stable circular polarization radiation performance.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A spiral circularly polarized satellite communication antenna, characterized in that, include: A power supply dielectric substrate has a metal ground plane on its first end face, and a dumbbell-shaped slot coupling structure is etched on the metal ground plane. A power supply network input and a power supply network output are spaced apart on the second end face opposite to the first end face. The power supply network output is located in the middle of the power supply dielectric substrate, and the projection of the power supply network output on the plane of the metal ground plane is perpendicular to the slot coupling structure. as well as A flexible dielectric substrate cylinder is vertically connected to the metal floor. A metal radiating arm is spirally wound around the outer surface of the flexible dielectric substrate cylinder, and the metal radiating arm is connected to the opposite ends of the power supply network output component through a metal connector.

2. The spiral circularly polarized satellite communication antenna according to claim 1, characterized in that, The slot coupling structure includes a rectangular connecting part and circular ends symmetrically arranged at opposite ends of the connecting part.

3. The spiral circularly polarized satellite communication antenna according to claim 1, characterized in that, The metal connector includes a metal post and a trapezoidal metal patch; the bottom of the metal post is vertically connected to the power supply network output component, the top of the metal post is connected to the first bottom edge of the metal patch, and the second bottom edge of the metal patch is connected to the metal radiating arm; the first bottom edge is parallel to the second bottom edge, and the length of the first bottom edge is less than the length of the second bottom edge.

4. The spiral circularly polarized satellite communication antenna according to claim 3, characterized in that, The metal pillar is cylindrical, and a cylindrical groove is formed on the first end face of the feeding dielectric substrate. A through hole coaxial with the groove is formed on the metal floor, and the metal pillar passes through the through hole and is adapted to the groove.

5. The spiral circularly polarized satellite communication antenna according to claim 1, characterized in that, The power supply network input component includes a microstrip transmission line and a patch circle, wherein the microstrip transmission line and the patch circle are integrally formed; the microstrip transmission line is parallel to the power supply network output component; the patch circle overlaps with the projection portion of the slot coupling structure on the plane where the power supply dielectric substrate is located.

6. The spiral circularly polarized satellite communication antenna according to claim 1, characterized in that, It also includes a first carbon-based cylindrical tube embedded in the flexible dielectric substrate tube, a second carbon-based cylindrical tube coaxially nested inside the first carbon-based cylindrical tube, and a flexible dielectric substrate surrounding the outer surface of the second carbon-based cylindrical tube.

7. The spiral circularly polarized satellite communication antenna according to claim 6, characterized in that, The flexible dielectric substrate has a plurality of symmetrical guide bands on its surface facing the first carbon-based cylindrical tube, and the plurality of guide bands are perpendicular to the feed dielectric substrate.

8. The spiral circularly polarized satellite communication antenna according to claim 7, characterized in that, The ratio of the width of the guide band to the width of the metal radiating arm is 1:

1.

9. An antenna array, characterized in that, It includes four spiral circularly polarized satellite communication antennas as described in any one of claims 1 to 8.

10. A drone, characterized in that, The antenna array as described in claim 9 further includes a wing, the top of which is connected to the second end face of the feed dielectric substrate.

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