Structure and preparation method of self-dimensional pure flexible fabric parabolic antenna

Abstract

The invention discloses a structure and a preparation method of a self-dimensional pure flexible fabric parabolic antenna, and belongs to the technical field of spherical inflatable antennas. The structure comprises a flexible fabric, a conductive silica gel layer and a plurality of silica gel ribs, criss-cross gradient thickness silica gel ribs are arranged on the back of the flexible fabric, non-uniform tension is induced during inflation expansion through the hyperelasticity and strain hardening effect of silica gel, the spherical surface of the flexible fabric is forced to spontaneously converge to a target paraboloid equation, and the outer surface of the flexible fabric is covered with a conductive silica gel layer. The method comprises the following steps: S1, laminating the flexible fabric and the conductive silica gel layer by adopting a vacuum laminating process; s2, manufacturing silica gel ribs on the non-reflecting surface of the flexible fabric; and S3, manufacturing silica gel ribs on the reflecting surface of the flexible fabric. According to the invention, the flexible silica gel is used as a reinforcing strip to realize the structural form of the self-dimensional effect of the antenna. The defect that deformation depends on single pneumatic control is overcome, folding resistance and high and low temperature resistance are achieved, and meanwhile good conductivity is achieved.

Description

Technical Field

[0001] This invention belongs to the field of spherical inflatable antenna technology, specifically relating to the structure and fabrication method of a self-supporting, purely flexible fabric parabolic antenna. Background Technology

[0002] 1. Technological Evolution of Spherical Antennas and Limitations of Rigid Structures

[0003] Spherical inflatable antennas (such as those from GATR) have become key equipment in satellite communications, emergency command, and other fields due to their high-gain parabolic surface and foldable portability. Their core principle is to inflate an antenna to form a spherical outer casing, and the internal air pressure difference causes the flexible reflective film to expand into a parabolic shape. However, existing technologies have the following inherent drawbacks:

[0004] Deformation relies on a single aerodynamic control: the shape of the reflector depends entirely on the stability of the internal air pressure. External wind, temperature fluctuations, or even minor leaks can cause air pressure changes, leading to parabolic distortion, which requires real-time air replenishment for compensation.

[0005] The paradox of rigid support structures: Some solutions attempt to add plastic ribs or metal mesh to the inside of the fabric layer to enhance rigidity, but this sacrifices folding efficiency and repeated bending can easily lead to the breakage of the support structure.

[0006] 2. Technical bottlenecks of existing flexible spherical antennas

[0007] To improve deformation stability, academia and industry have explored various flexible structures, but the core problem remains unresolved:

[0008] Uncontrolled deformation of pure fabric structures: Although pure flexible fabrics (such as nylon-coated TPU) achieve ultra-light folding, the curvature of the sphere after inflation is a uniform sphere rather than a precise parabola, resulting in insufficient beam focusing ability (the measured gain is 4–6 dB lower than the theoretical value).

[0009] Lack of dynamic deformation compensation: Existing controllable deformation solutions (such as motor-driven rope tensioning) require an external power system (such as the key rope mechanism in patent CN116207504A), which significantly increases weight and failure rate, and the response delay is >500ms, making it unable to adapt to real-time wind vibration disturbances.

[0010] Mechanical mismatch between conductive layer and substrate: Metal plating (such as silver paste) or conductive fabric (such as copper mesh) coated on fabric surface is prone to microcracks under repeated deformation, resistivity increases by >300%, and high frequency loss increases dramatically (Ku band efficiency <35%).

[0011] The spherical inflatable antenna back frame structure uses inflatable tubes as a self-supporting structure on the back of the antenna. However, this solution is only feasible for larger antennas, such as those with a diameter > 4m. It requires smaller antennas, such as those with a diameter of 500mm or 1m, where the diameter of the inflatable tubes used is at most 2-3cm, significantly increasing the manufacturing difficulty. It also requires external inflation interfaces and external pressure measurement interfaces. The circumferential and longitudinal air tubes need to be interconnected, meaning all circumferential and longitudinal air tubes are inflated through a single inflation port. This greatly increases the difficulty of control, and damage to one part affects the entire structure. The inflatable tube network is fixed to the antenna with adhesive. When not in use, the spherical antenna needs to be folded and retracted, significantly reducing the lifespan of the inflatable tubes. Summary of the Invention

[0012] To address the aforementioned problems, this invention provides a structure and fabrication method for a self-sustaining, purely flexible fabric parabolic antenna. This is an embedded structure with no external power and high deformation resilience, capable of achieving parabolic self-sustaining based on aerodynamic control.

[0013] The technical solution adopted in this invention is:

[0014] A structure of a self-supporting, purely flexible fabric parabolic antenna includes a flexible fabric, a conductive silicone layer, and multiple silicone ribs;

[0015] By setting crisscrossing gradient-thickness silicone ribs on the back of the flexible fabric, non-uniform tension is induced during inflation due to the hyperelasticity and strain hardening effect of silicone, forcing the spherical surface of the flexible fabric to spontaneously converge to the target parabolic equation.

[0016] A conductive silicone layer is coated on the outer surface of the flexible fabric.

[0017] A method for fabricating a self-supporting, purely flexible fabric parabolic antenna includes the following steps:

[0018] S1. A vacuum lamination process is used to bond the flexible fabric to the conductive silicone layer;

[0019] S2. Fabricate silicone ribs on the non-reflective surface of a flexible fabric;

[0020] S3. Create silicone ribs on the reflective surface of the flexible fabric.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention uses flexible silicone as a reinforcing strip to achieve a self-shaping antenna structure.

[0023] 1. This invention overcomes the weakness of deformation relying on a single pneumatic control.

[0024] 2. This invention is resistant to folding, high and low temperatures, and also has good electrical conductivity.

[0025] 3. The self-supporting ribs of the present invention are made of the same silicone material as those used in parabolic antennas, and have good adhesion.

[0026] 4. By using a longitudinal rib thickness greater than the circumferential rib thickness, this invention can smooth the stiffness gradient and reduce the risk of fatigue damage.

[0027] 5. For larger parabolic antennas that cannot be directly fabricated from fabric, this invention allows for segmented fabrication followed by merging, where the longitudinal silicone strips serve as splicing links.

[0028] 6. Compared to mechanical structures, the present invention, as a parabolic antenna with a three-dimensional structure, has the characteristics of being lightweight, foldable, and flexible.

[0029] 7. Compared with the inflatable back tube structure, the present invention, as a parabolic antenna shape structure, has the characteristics of not requiring external energy input and relying on the intrinsic mechanical properties of the material to maintain its shape, and is not afraid of damage. Damage to a single place or even some areas has little impact on the whole.

[0030] 8. The silicone ribs of this invention will have corresponding materials added to improve the rigidity of the silicone after curing.

[0031] 9. Weight controllability: The weight of the silicone strip is related to its thickness, and the weight of the silicone strip can be adjusted directly by adjusting the thickness of the silicone strip. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the present invention (non-reflective surface);

[0033] Figure 2 This is a schematic diagram of the structure of the present invention (reflective surface);

[0034] Figure 3 This is a schematic diagram of the mold preparation of the longitudinal silicone ribs of the present invention;

[0035] Figure 4 This is a schematic diagram of the mold preparation of the circumferential silicone ribs according to the present invention;

[0036] Among them: 1. Flexible fabric; 2. Silicone ribs; 3. Mold; 301. Arc-shaped bottom mold; 302. Longitudinal baffle; 303. Circumferential baffle. Detailed Implementation

[0037] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0038] To fabricate an embedded structure with no external power source and high deformation resilience, and to achieve parabolic self-sustaining based on pneumatic control, the following conditions are required:

[0039] Material requirements: It needs to have both high elastic modulus (to maintain surface curvature) and high elongation at break (to accommodate folding deformation). Traditional silicone (such as PDMS) has insufficient resilience (permanent deformation rate > 10%), while shape memory polymers (SMP) require thermal activation and cannot respond quickly to changes in air pressure.

[0040] Structural dimension: A non-uniform stiffness distribution needs to be established so that the sphere spontaneously evolves into a parabola after inflation. Existing uniform reinforcing layers (such as integral silicone coating) improve stiffness, but suppress the curvature gradient required for a parabola.

[0041] Meanwhile, the technical problem that this invention aims to solve is:

[0042] Passive parabolic self-organization: It does not require external energy input and relies on the intrinsic mechanical properties of the material to counteract air pressure disturbances;

[0043] Folding-Electrical Compatibility: Silicone / metal composite system balances deformation resistance and high-frequency conductivity;

[0044] Integrated structure and function: The silicone ribs simultaneously perform three functions: mechanical regulation, conductive circuit and airtight barrier.

[0045] Independent support structure: The silicone ribs are formed after the glue has cured, so damage in some areas has no impact on the overall structure.

[0046] This design provides a new technological paradigm for highly reliable portable satellite communication equipment, solving the problem of having good self-shaping technology while ensuring the use of existing flexible antenna materials, and getting rid of the pain point of deformation relying on a single aerodynamic control.

[0047] Therefore, this invention proposes a back-embedded flexible silicone longitudinal and transverse distribution structure, which achieves a self-contained parabolic surface through biomimetic mechanical design:

[0048] The topological strengthening mechanism of silicone: crisscrossing gradient thickness silicone ribs 2 are added to the back (non-reflective surface) of flexible fabric 1. By utilizing the hyperelasticity and strain hardening effect of silicone, non-uniform tension is induced during inflation, forcing the spherical surface of flexible fabric 1 to spontaneously converge to the target parabolic equation.

[0049] Electromechanical performance synergistic optimization: A conductive silicone layer is coated on the outer surface of the flexible fabric 1;

[0050] Conductive silicone is made by incorporating silica / liquid metal mixed filler into the silicone of the conductive silicone layer, which achieves low resistivity while maintaining flexibility, thus solving the problem of electrical degradation of traditional metal coatings under deformation.

[0051] Integrated airtight and conductive properties: The molten interface between the silicone ribs 2 and the flexible fabric substrate 1 forms a sealing barrier.

[0052] The fabrication method for a self-supporting, purely flexible fabric parabolic antenna includes the following steps:

[0053] S1. A vacuum lamination process is used to bond the flexible fabric 1 to the conductive silicone layer. The flexible fabric 1 is a planar bidirectional fabric with large deformation capacity. Under the action of the silicone ribs 2, it can directly form a parabolic structure. The combination of silicone and fabric provides flexibility and foldability, while the fabric determines its low deformation and high strength.

[0054] S2. Fabricate silicone ribs 2 on the non-reflective surface of flexible fabric 1;

[0055] After the flexible fabric 1 is bonded to the conductive silicone layer, on the back side of the entire parabolic surface of the flexible fabric 1, i.e. the non-reflective surface, circumferential silicone ribs 2 are first prepared using the corresponding mold 3. After that, longitudinal silicone ribs 2 are prepared, which is the same as the method for preparing circumferential silicone ribs 2 in the previous step, and the thickness of longitudinal silicone ribs 2 is greater than that of circumferential silicone ribs 2.

[0056] The mold 3 includes an arc-shaped bottom mold 301, two longitudinal baffles 302, and multiple sets of circumferential baffles 303. The arc-shaped bottom mold 301 has an upward arc-shaped protrusion in the middle and an annular plane on the outer edge. Multiple sets of connecting holes 1 are evenly distributed on the annular plane, with two connecting holes 1 in each set. The two ends of the two longitudinal baffles 302 are flat plates with connecting holes 2. The connecting holes 2 of the two longitudinal baffles 302 cooperate with any set of connecting holes 1 to fix the gap between the two longitudinal baffles 302 on the arc-shaped bottom mold 301. The middle part of the two longitudinal baffles 302 is an arc-shaped plate with the same arc curvature as the arc-shaped protrusion of the arc-shaped bottom mold 301. The upper surfaces of the multiple sets of annular baffles 303 are all concave arc-shaped, and the multiple sets of annular baffles 303 can be spliced ​​into a ring.

[0057] Mold 3 is made of stainless steel.

[0058] The silicone rib 2 contains more than 50% silver-plated copper powder, platinum curing water, resin, and white carbon black. It is a high-viscosity silicone with a fast solidification speed of about five minutes.

[0059] The method of using mold 3 is as follows:

[0060] First, prepare the circumferential silicone ribs 2. Install multiple sets of circumferential baffles 303 in corresponding positions, with the upper surfaces of the multiple sets of circumferential baffles 303 forming a ring. Due to the high viscosity of silicone, the circumferential tool can be pressed down or a tool can be used to apply the silicone onto the upper surfaces of the multiple sets of circumferential baffles 303. After determining the thickness, place the entire assembly into a high-temperature oven. After high-temperature reaction to accelerate curing, connect the circumferential silicone ribs 2 to the back of the parabolic surface. Repeat this process to produce the remaining circumferential ribs in one go.

[0061] Then, the longitudinal silicone ribs 2 are prepared by two longitudinal baffles 302, the specific method of which is described below.

[0062] S3. Make silicone ribs 2 on the reflective surface of flexible fabric 1.

[0063] S31. When making the reflector of a large-sized (parabolic busbar length exceeds 1.5m) flexible fabric 1, the reflector of the entire flexible fabric 1 is first cut into equal parts, prepared in a segmented manner, and finally spliced ​​together to form a complete set of parabolic antennas.

[0064] S32. In 3D design software, rotate the parabolic generatrix of flexible fabric 1 according to the angle, and divide the triangular surface into a mesh;

[0065] S33. Perform parametric mapping, maintain geometric and topological relationships, and then perform overall optimization and boundary condition adjustment to obtain the planar pattern of the segmented antenna;

[0066] S34. The flexible fabric 1 with a single triangular face is bonded to the conductive silicone layer according to the vacuum lamination process. After all faces are prepared, it is laid flat on the mold 3 and splicing begins.

[0067] S35. Perform longitudinal splicing of silicone ribs 2, with the seam dividing line at the edge of the triangular face. The silicone ribs 2 need to be evenly distributed on the surface. For example, if the silicone rib is 2cm wide, it means that it is 1cm wide on each triangular face. The dividing line of the triangular face is located at the center of the silicone rib 2.

[0068] S36. After the longitudinal silicone ribs 2 have cured at high temperature, the circumferential silicone ribs 2 are spliced ​​to ensure that the thickness of the longitudinal silicone ribs 2 is greater than the thickness of the circumferential silicone ribs 2.

[0069] The outermost circumferential silicone rib 2 has the same diameter as the parabolic diameter of the flexible fabric 1.

[0070] Adhesive strips are bonded to the bottom of the two longitudinal baffles 302, and the annular plane of the outer edge is fixed to the arc-shaped bottom mold 301 with bolts. The adhesive strips are tightly bonded to the parabolic surface of the arc-shaped bottom mold 301. At this point, high-viscosity silicone adhesive is poured into the gap between the two longitudinal baffles 302 and smoothed using a silicone scraper. After curing, the longitudinal baffles 302 are removed to prepare silicone ribs 2 at another angle. The first silicone rib 2 prepared at this point will cause friction with the longitudinal baffles 302. Therefore, the adhesive strip below the longitudinal baffles 302 is shortened according to the corresponding position. The second silicone rib 2 is prepared in the same manner.

[0071] After the longitudinal silicone ribs 2 are prepared, the circumferential silicone ribs 2 are prepared. First, a bottom mold 3 with a suitable angle (determined by the number of longitudinal silicone ribs 2 to be made; for 6 ribs, it would be 60° - 5° = 55°; the -5° is to avoid the longitudinal silicone ribs 2, and the 5° is defined according to the width of the longitudinal silicone ribs) is selected. Mold 3 can be made of epoxy resin, which is lighter and easier to control than stainless steel. Before preparing the circumferential silicone ribs 2, a release agent is first sprayed onto the surface of mold 3. Then, high-viscosity silicone is piled up, with the silicone height defined according to the actual situation.

[0072] The circumferential silicone ribs 2 are prepared from top to bottom, starting with the ones at the center and then the ones at the edges.

[0073] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A structure for a self-supporting, purely flexible fabric parabolic antenna, characterized in that: It includes a flexible fabric (1), a conductive silicone layer and multiple silicone ribs (2); Interlaced gradient-thickness silicone ribs (2) are set on the back of the flexible fabric (1). Through the hyperelasticity and strain hardening effect of silicone, non-uniform tension is induced during inflation, forcing the spherical surface of the flexible fabric (1) to spontaneously converge to the target parabolic equation. A conductive silicone layer is covered on the outer surface of the flexible fabric (1).

2. The structure of a self-supporting, purely flexible fabric parabolic antenna according to claim 1, characterized in that: The conductive silicone layer is made by inserting silica or liquid metal mixed filler into the silicone.

3. The structure of a self-supporting, purely flexible fabric parabolic antenna according to claim 1, characterized in that: The flexible fabric (1) is a bidirectional fabric.

4. A method for fabricating a self-supporting, purely flexible fabric parabolic antenna according to any one of claims 1 to 3, characterized in that: Includes the following steps: S1. A vacuum lamination process is used to bond the flexible fabric (1) to the conductive silicone layer; S2. Silicone ribs (2) are made on the non-reflective surface of the flexible fabric (1); S3. Silicone ribs (2) are made on the reflective surface of the flexible fabric (1).

5. The method for fabricating a self-supporting, purely flexible fabric parabolic antenna according to claim 4, characterized in that: The specific process of fabricating silicone ribs (2) on the non-reflective surface of the flexible fabric (1) in S2 is as follows: On the non-reflective surface of the flexible fabric (1), circumferential silicone ribs (2) are first prepared using a mold (3); after completion, longitudinal silicone ribs (2) are prepared, which is the same as the previous step of preparing circumferential silicone ribs (2), and the thickness of longitudinal silicone ribs (2) is greater than that of circumferential silicone ribs (2).

6. The method for fabricating a self-supporting, purely flexible fabric parabolic antenna according to claim 4, characterized in that: In step S3, the silicone ribs (2) are fabricated on the reflective surface of the flexible fabric (1), including the following steps: S31. When making a large-sized flexible fabric (1) reflector, the entire flexible fabric (1) reflector is first cut into equal parts and prepared in a segmented manner. Finally, it is spliced ​​together to form a complete set of parabolic antennas. S32. In 3D design software, rotate the parabolic generatrix of the flexible fabric (1) according to the angle, and divide the triangular surface into a mesh; S33. Perform parametric mapping, maintain geometric and topological relationships, and then perform overall optimization and boundary condition adjustment to obtain the planar pattern of the segmented antenna; S34. The flexible fabric (1) of a single triangular face is bonded to the conductive silicone layer according to the vacuum lamination process. After all the faces are prepared, it is laid flat on the mold (3) and splicing begins. S35. Perform longitudinal splicing of silicone ribs (2), with the seam dividing line at the edge of the triangular face, the silicone ribs (2) are evenly distributed on the surface, and the dividing line of the triangular face is located at the center of the silicone ribs (2). S36. After the longitudinal silicone ribs (2) have cured at high temperature, the circumferential silicone ribs (2) are spliced ​​to ensure that the thickness of the longitudinal silicone ribs (2) is greater than the thickness of the circumferential silicone ribs (2).

7. The method for fabricating a self-supporting, purely flexible fabric parabolic antenna according to claim 6, characterized in that: In S3, the outermost circumferential silicone rib (2) has the same diameter as the parabolic diameter of the flexible fabric (1).

8. The method for fabricating a self-supporting, purely flexible fabric parabolic antenna according to claim 5, characterized in that: The mold (3) includes an arc-shaped bottom mold (301), two longitudinal baffles (302) and multiple sets of circumferential baffles (303); the arc-shaped bottom mold (301) has an upward arc-shaped protrusion in the middle and an annular plane on the outer edge; multiple sets of connecting holes are evenly distributed on the annular plane, with two connecting holes in each set; both ends of the two longitudinal baffles (302) are flat plates and are provided with connecting holes; the connecting holes of the two longitudinal baffles (302) cooperate with any set of connecting holes to fix the gap between the two longitudinal baffles (302) on the arc-shaped bottom mold (301); the middle of the two longitudinal baffles (302) is an arc-shaped plate and has the same arc as the arc-shaped protrusion of the arc-shaped bottom mold (301); the multiple sets of circumferential baffles (303) can be spliced ​​into a ring.

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