An oblate spheroid streamlined low-scattering carrier and a design method thereof

Abstract

This invention discloses a flattened ellipsoidal streamlined low-scattering carrier, comprising a centrally symmetric flattened ellipsoidal streamlined shell, including a coaxial and identical top circular surface and a bottom circular surface, and a smooth transition surface between them. The smooth transition surface is formed by rotating a generatrix around a central axis. The generatrix is ​​a smooth transition curve generated by lofting three cross-sectional surfaces and passing through the edges of the three cross-sections. The three cross-sections include the top circular surface, the bottom circular surface, and an intermediate reference plane located between them. The top and bottom circular surfaces are mirror-symmetric with respect to the intermediate reference plane. The diameters of the top and bottom circular surfaces are smaller than the diameter of the intermediate reference plane, and the vertical distance between them and the intermediate reference plane is the structural height. The three diameters and the structural height are related to the center wavelength of the target radar threat frequency band. This invention, through parameterized geometric proportion design, can obtain a carrier shape with stable low-scattering performance over a wide bandwidth and excellent high-frequency extension potential.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic scattering control technology, and more specifically to a carrier and its shape design method for reducing radar cross section (RCS), particularly a flat ellipsoidal streamlined low-scattering carrier and its design method. Background Technology

[0002] Reducing a target's radar cross-section (RCS) is a key way to improve its stealth performance. Shape stealth technology, by designing specific geometric configurations, directs the main reflected energy of incident radar waves to non-threatening directions, thereby reducing the echo intensity in the critical detection angle domain.

[0003] As a classic low-scattering design, the teardrop shape, with its continuously varying curvature, can guide the energy of electromagnetic waves incident from the front to both sides over a wide frequency band, achieving RCS performance superior to simple geometric shapes such as cylinders and spheres.

[0004] However, as radar systems evolve towards multi-band and wideband applications, especially when expanding to higher frequencies, the performance of the traditional teardrop-shaped design faces challenges: its scattering energy control efficiency may decrease at high frequencies, its RCS curve is prone to fluctuations, and its stability and consistency need to be improved.

[0005] Therefore, how to provide a new RCS carrier shape and its design method with better and more stable low scattering performance over a wide frequency band is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the above problems, the present invention is proposed to provide a flat ellipsoidal streamlined low-scattering carrier and its design method to overcome or at least partially solve the above problems, which can generate a carrier shape with excellent broadband low-scattering characteristics and the potential to extend to higher frequency bands.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide a flattened ellipsoidal streamlined low-scattering carrier, comprising: A centrally symmetric, flattened ellipsoidal streamlined shell; the flattened ellipsoidal streamlined shell is a closed structure, including a coaxial and identical top circular surface and a bottom circular surface, and a smooth transition surface between the top circular surface and the bottom circular surface; The smooth transition surface is formed by rotating a generatrix around the central axis of the top and bottom circular surfaces; wherein, the generatrix is ​​a smooth transition curve generated by lofting three cross-sectional surfaces and passing through the edges of the three cross-sections, the three cross-sections including the top and bottom circular surfaces, and an intermediate reference circular surface that is parallel to the top and bottom circular surfaces and located between the top and bottom circular surfaces, the top and bottom circular surfaces being mirror-symmetric with respect to the intermediate reference circular surface; The diameters of the top and bottom circular surfaces are smaller than the diameter of the middle reference circular surface, and the vertical distance between the top and bottom circular surfaces and the middle reference circular surface is the construction height; the diameters of the top and bottom circular surfaces, the diameter of the middle reference circular surface, and the construction height satisfy a preset geometric ratio relationship with the center wavelength of the target radar threat band.

[0009] Preferably, the preset geometric proportions include: The ratio of the top circular surface diameter to the bottom circular surface diameter to the middle reference circular surface diameter ranges from 1 / 3 to 1 / 5; The ratio of the structure height to the diameter of the intermediate reference circle ranges from 1 / 6 to 1 / 10.

[0010] Preferably, the diameter of the intermediate reference circle is associated with the center wavelength of the target radar threat band.

[0011] Preferably, the diameter D of the intermediate reference circular surface mid The frequency band of the target radar threat band is a multiple of the center wavelength λ: D mid =mλ, where m is the multiplier coefficient.

[0012] Preferably, the multiplier m ranges from 6 to 10.

[0013] Secondly, embodiments of the present invention provide a design method for a streamlined, low-scattering carrier based on the aforementioned oblate spheroid, comprising the following steps: S1. Determine the center wavelength of the target radar threat band; S2. Construct a 3D solid model, including: S21. Define three parallel reference planes in three-dimensional space, including a middle reference circle, an upper plane above the middle reference circle, and a lower plane below the middle reference circle. The distances of the upper plane and the lower plane from the middle reference circle are equal as the construction height values. S22. Create an intermediate reference circular surface on the intermediate reference circular surface; create a top circular surface on the upper plane; create a bottom circular surface on the lower plane; the intermediate reference circular surface, the top circular surface, and the bottom circular surface are coaxial; S23. Generate a smooth transition curve that passes through the edges of the top circular surface, the middle reference circular surface and the bottom circular surface simultaneously as a generatrix. Rotate the generatrix around an axis that passes through the middle reference circular surface, the top circular surface and the bottom circular surface coaxially to form a smooth transition surface. S24. Fill the opening end faces corresponding to the top and bottom circular surfaces to obtain a closed three-dimensional solid model; S3. Based on the center wavelength and the preset geometric ratio, determine the values ​​of the diameter and structural height of the middle reference circle, the top circle, and the bottom circle; S4. Based on the three-dimensional solid model constructed in step S2 and the values ​​determined in S3, establish a three-dimensional electromagnetic simulation model of the three-dimensional solid model and perform scattering performance simulation. Iteratively optimize the values ​​according to the simulation results until the preset performance indicators are met.

[0014] Preferred, preset geometric proportions include: The ratio of the top circular surface diameter to the bottom circular surface diameter to the middle reference circular surface diameter ranges from 1 / 3 to 1 / 5; The ratio of the structure height to the diameter of the intermediate reference circle ranges from 1 / 6 to 1 / 10.

[0015] Preferably, the diameter of the intermediate reference circle is associated with the center wavelength of the target radar threat band.

[0016] Preferably, the diameter D of the intermediate reference circular surface mid The frequency band of the target radar threat band is a multiple of the center wavelength λ: D mid =mλ, where m is the multiplier coefficient.

[0017] Preferably, in step S4, the scattering performance simulation includes: setting a vertically polarized plane wave to be incident normally along the central axis of the carrier, and analyzing the radar scattering cross section values ​​and curve fluctuation characteristics within the target threat frequency band within the azimuth angle ±30° to iteratively optimize the values ​​for the target.

[0018] The specific beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following: The flattened ellipsoidal streamlined low-scattering carrier system provided by this invention has stronger system integration and outstanding broadband performance potential. Focusing on the direct correlation between key dimensions and the radar center wavelength λ, a parametric design process is constructed using multiplier factors m and optimized key geometric proportions. The design method is logically clear and highly operable. Its parameter system helps generate a carrier shape with coordinated curvature distribution, providing a reliable geometric foundation and design paradigm for achieving efficient scattered energy guidance and stable low RCS performance over a wide bandwidth.

[0019] This invention possesses high-frequency expansion potential and also boasts engineering practicality. The carrier generated by this invention has a smooth, continuous, and centrally symmetrical shape, avoiding sharp discontinuities that easily lead to strong scattering. Its design principle is consistent with the principle of electrical dimension scaling, and it can adapt to different center wavelengths (frequency) by scaling the absolute size proportionally. Furthermore, the modeling method used is standard and universal, and the generated shape is easily realized through modern manufacturing processes such as CNC machining and composite material molding, possessing both good theoretical expansion potential and promising engineering transformation prospects. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a structural diagram of the flattened ellipsoidal streamlined low-scattering carrier provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the principle of generating a smooth transition surface provided in an embodiment of the present invention; Figure 3 This is a comparison curve obtained from electromagnetic simulation provided in an embodiment of the present invention. Detailed Implementation

[0022] 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.

[0023] This invention discloses a flattened ellipsoidal streamlined low-scattering carrier to address the problem of insufficient performance stability of existing low-scattering shapes over a wide frequency band, especially at higher frequencies. Combined with... Figure 1 As shown, the explanation is as follows: The flattened ellipsoidal streamlined low-scattering carrier includes: a centrally symmetric flattened ellipsoidal streamlined shell; the flattened ellipsoidal streamlined shell is a closed structure, including a coaxial and identical top circular surface and a bottom circular surface, and a smooth transition surface between the top circular surface and the bottom circular surface; A smooth transition surface is formed by rotating a generatrix around the central axis of the top and bottom circular surfaces. The generatrix is ​​a smooth transition curve generated by lofting three cross-sectional surfaces and passing through the edges of these three cross-sections. The three cross-sections include the top and bottom circular surfaces, and an intermediate reference circular surface parallel to and located between the top and bottom circular surfaces. The top and bottom circular surfaces are mirror-symmetric with respect to the intermediate reference circular surface. Figure 2 The diagram shows the principle of generating the upper half of the flattened ellipsoidal streamlined shell by rotating the generatrix segment between the top circular surface and the middle reference circular surface. The lower half of the flattened ellipsoidal streamlined shell is generated in the same way.

[0024] The diameters of the top and bottom circular surfaces are smaller than the diameter of the middle reference circular surface; the vertical distance between the top and bottom circular surfaces and the middle reference circular surface is the construction height; the diameter D of the top circular surface... top and the diameter D of the bottom circular surface bottom The diameter D of the intermediate reference circle mid and structural height H set The frequency band of the target radar threat band satisfies a preset geometric ratio.

[0025] It should be noted that the diameter D of the top circular surface top and the diameter D of the bottom circular surface bottom equal.

[0026] In one embodiment, the preset geometric proportions include: The ratio of the top circular surface diameter to the bottom circular surface diameter to the middle reference circular surface diameter ranges from 1 / 3 to 1 / 5. This ratio affects the degree of convergence and longitudinal curvature distribution at the top of the carrier. The ratio of the structural height to the diameter of the intermediate reference circle ranges from 1 / 6 to 1 / 10, and this ratio determines the flatness and lateral curvature distribution of the carrier.

[0027] In one embodiment, the diameter of the intermediate reference circle is associated with the center wavelength of the target radar threat band.

[0028] In one embodiment, the diameter D of the intermediate reference circle... mid The frequency band of the target radar threat band is a multiple of the center wavelength λ: D mid =mλ, where m is the multiplier coefficient.

[0029] In one embodiment, the multiplier m ranges from 6 to 10.

[0030] Based on the same inventive concept, this invention also provides a design method for a streamlined low-scattering carrier based on an oblate spheroid, comprising the following steps: S1. Determine the center wavelength of the target radar threat band; S2. Construct a 3D solid model, including: S21. Define three parallel reference planes in three-dimensional space, including an intermediate reference circle, an upper plane above the intermediate reference circle, and a lower plane below the intermediate reference circle. The distances of the upper plane and the lower plane from the intermediate reference circle are equal as the construction height values. S22. Create a middle reference circle on the middle reference circle; create a top circle on the upper plane; create a bottom circle on the lower plane; the middle reference circle, top circle, and bottom circle are coaxial; S23. Generate a smooth transition curve that passes through the edges of the top circular surface, the middle reference circular surface, and the bottom circular surface simultaneously as a generatrix. Rotate the generatrix around an axis that passes through the middle reference circular surface, the top circular surface, and the bottom circular surface to form a smooth transition surface. S24. Fill the corresponding open end faces of the top and bottom circular surfaces to obtain a closed three-dimensional solid model. S3. Based on the center wavelength and the preset geometric ratio, determine the values ​​of the diameter and structural height of the middle reference circle, the top circle, and the bottom circle; S4. Based on the three-dimensional solid model constructed in step S2 and the values ​​determined in S3, establish a three-dimensional electromagnetic simulation model of the three-dimensional solid model and perform scattering performance simulation. Iteratively optimize the values ​​according to the simulation results until the preset performance indicators are met.

[0031] In practice, a smooth transition surface for the upper half of the flattened ellipsoidal streamlined shell can be generated first based on the top circular surface and the middle reference circular surface. Then, by mirroring and flipping, a smooth transition surface for the lower half of the same 3D solid model can be obtained. Together, they form a complete smooth transition surface. Finally, the top and bottom circular surfaces are filled with solids, forming a closed 3D solid model together with the smooth transition surface.

[0032] It should be noted that the intermediate reference circle is not filled with solids.

[0033] In one embodiment, the preset geometric proportions include: The ratio of the top circular diameter to the bottom circular diameter to the middle reference circular diameter ranges from 1 / 3 to 1 / 5; The ratio of the structural height to the diameter of the intermediate reference circle ranges from 1 / 6 to 1 / 10.

[0034] In one embodiment, the diameter of the intermediate reference circle is associated with the center wavelength of the target radar threat band.

[0035] In one embodiment, the diameter D of the intermediate reference circle... mid The frequency band of the target radar threat band is a multiple of the center wavelength λ: Dmid =mλ, where m is the multiplier coefficient.

[0036] In one embodiment, step S4 includes: setting a vertically polarized (VV polarized) plane wave to be incident along the central axis of the carrier, performing scattering performance simulation within the target threat frequency band, and analyzing the radar cross section values ​​and curve fluctuation characteristics within an azimuth angle of ±30° to iteratively optimize the target logarithmic values.

[0037] This embodiment focuses on analyzing the RCS values ​​and curve fluctuation characteristics within an azimuth angle range of ±30°. Based on the simulation results, the multiplier m and diameter ratio D can be adjusted. top / D mid and height ratio H set / D mid Iterative optimization is performed within the given range until the performance metrics are met.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. This embodiment demonstrates the design of a low-scattering flattened ellipsoidal streamlined carrier using the method of the present invention, and verifies its performance through simulation comparison with a traditional teardrop-shaped carrier.

[0039] 1: Design Input and Parameter Calculation: a. Selection of verification frequency points: To evaluate broadband performance, the typical S-band frequency point 3GHz (λ1=100mm) and the typical C-band frequency point 6GHz (λ2=50mm) were selected as verification targets.

[0040] b. Determine the external parameters: Using a higher frequency of 6GHz as the design benchmark. Taking a multiplier m=8, the diameter D of the intermediate reference circle is... mid =8 × 50 mm = 400 mm. Take the diameter ratio D. top / D mid =1 / 4, then the diameter D of the top circular surface top =100 mm. Take the height ratio H. set / D mid =1 / 8, then the construction height H set =50 mm. Designed with a higher frequency of 6 GHz as a baseline, while evaluating its performance at 3 GHz.

[0041] 2. Parametric modeling: a. In 3D modeling software (such as CATIA), create two parallel planes with a spacing of H. set =50 mm.

[0042] b. On the reference plane below, create a circle with diameter D centered at the origin. mid =400 mm circle, i.e., the central reference circle.

[0043] c. On the plane above, using the same XY coordinate points as centers, create circles with a diameter of D. top =100 mm circle, i.e. top circular surface.

[0044] d. Using the multi-section surface or lofting function, select the middle reference circle and the top circle as sections in sequence, and generate a smooth transition curve that passes through the edges of the top circle, the middle reference circle, and the bottom circle as the generatrix.

[0045] e. Using the rotation function, rotate the generatrix generated in the previous step 360° around the vertical axis (Z-axis) passing through the centers of the two circles to obtain half of the outline surface.

[0046] f. The obtained half-contour surface is flipped and mirrored to obtain a complete contour surface that is symmetrical from top to bottom; g. Use the circle fill function to fill the top and bottom circles to obtain a complete, closed, flat ellipsoidal streamlined 3D solid model.

[0047] h. At the same time, in order to compare performance, a classic teardrop-shaped 3D model with the same maximum projected diameter (400 mm) and similar overall outline length is established.

[0048] 3. Simulation analysis results: The flattened ellipsoid streamlined model and the teardrop-shaped comparative model established above were imported into electromagnetic simulation software (such as FEKO). Simulation conditions were set as follows: vertically polarized (VV-polarized) plane waves were incident normally along the central axis (Z-axis) of the carrier. The monostatic RCS of the two models at 3 GHz and 6 GHz were calculated respectively. The simulation results were compared and analyzed, as follows: Figure 3 As shown: At the 3GHz frequency (S-band): Figure 3 (a) shows that the peak RCS of the flattened ellipsoidal streamlined carrier designed in this invention near the 0° azimuth angle is significantly lower than that of the traditional teardrop-shaped carrier. At the same time, within the ±30° observation angle range, the overall RCS curve of the flattened ellipsoidal streamlined carrier is lower and the fluctuations are smoother, showing better angular domain stability.

[0049] At the 6 GHz frequency (C-band): At this higher frequency, the advantages of the flat ellipsoidal streamlined carrier are even more significant. Figure 3 (b) shows that its RCS can be stably maintained at a low level below -35 dBsm within the ±30° range, and the curve is smooth with minimal fluctuations. In contrast, the teardrop-shaped carrier still has a relatively high scattering peak (about -34 dBsm) at the 0° azimuth angle, and the RCS curve fluctuates relatively significantly within the observation angular domain.

[0050] Simulation data from both frequencies show that the flattened ellipsoidal streamlined carrier generated by the design method of this invention exhibits superior low scattering performance compared to traditional teardrop-shaped carriers at both 3GHz and 6GHz frequencies. Specifically, this is reflected in lower RCS peak values, lower average RCS levels, and a smoother RCS curve (i.e., better angular domain stability), with even more pronounced performance advantages at higher frequencies (6GHz).

[0051] This embodiment verifies the effectiveness of the flattened ellipsoidal streamlined low-scattering carrier design method provided by this invention through simulation comparisons at two representative frequency points: 3GHz and 6GHz. The carrier designed according to this method exhibits superior low RCS performance and stability over a wide frequency band. The frequency adaptability (related to dimensions through wavelength λ) and performance advantages in the high-frequency band demonstrated by this design method indicate that, by scaling the design dimensions proportionally (keeping core parameters such as m, diameter ratio, and height ratio unchanged), this flattened ellipsoidal streamlined structure and design method have the potential to be extended to higher radar frequency bands (such as the X-band and above).

[0052] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0053] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flattened ellipsoidal streamlined low-scattering carrier, characterized in that, include: A centrally symmetric, flattened ellipsoidal streamlined shell; The flattened ellipsoidal streamlined shell is a closed structure, including a coaxial and identical top circular surface and a bottom circular surface, as well as a smooth transition surface between the top and bottom circular surfaces; The smooth transition surface is formed by rotating a generatrix around the central axis of the top and bottom circular surfaces; wherein, the generatrix is ​​a smooth transition curve generated by lofting three cross-sectional surfaces and passing through the edges of the three cross-sections, the three cross-sections including the top and bottom circular surfaces, and an intermediate reference circular surface that is parallel to the top and bottom circular surfaces and located between the top and bottom circular surfaces, the top and bottom circular surfaces being mirror-symmetric with respect to the intermediate reference circular surface; The diameters of the top and bottom circular surfaces are smaller than the diameter of the middle reference circular surface, and the vertical distance between the top and bottom circular surfaces and the middle reference circular surface is the construction height; the diameters of the top and bottom circular surfaces, the diameter of the middle reference circular surface, and the construction height satisfy a preset geometric ratio relationship with the center wavelength of the target radar threat band.

2. The flattened ellipsoidal streamlined low-scattering carrier as described in claim 1, characterized in that, The preset geometric proportions include: The ratio of the top circular surface diameter to the bottom circular surface diameter to the middle reference circular surface diameter ranges from 1 / 3 to 1 / 5; The ratio of the structure height to the diameter of the intermediate reference circle ranges from 1 / 6 to 1 / 10.

3. The flattened ellipsoidal streamlined low-scattering carrier as described in claim 1, characterized in that, The diameter of the intermediate reference circle is associated with the center wavelength of the target radar threat band.

4. The flattened ellipsoidal streamlined low-scattering carrier as described in claim 3, characterized in that, The diameter D of the intermediate reference circle mid The frequency band of the target radar threat band is a multiple of the center wavelength λ: D mid =mλ, where m is the multiplier.

5. The flattened ellipsoidal streamlined low-scattering carrier as described in claim 4, characterized in that, The multiplier m ranges from 6 to 10.

6. A design method for a flattened ellipsoidal streamlined low-scattering carrier as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Determine the center wavelength of the target radar threat band; S2. Construct a 3D solid model, including: S21. Define three parallel reference planes in three-dimensional space, including a middle reference circle, an upper plane above the middle reference circle, and a lower plane below the middle reference circle. The distances of the upper plane and the lower plane from the middle reference circle are equal as the construction height values. S22. Create an intermediate reference circular surface on the intermediate reference circular surface; create a top circular surface on the upper plane; create a bottom circular surface on the lower plane; the intermediate reference circular surface, the top circular surface, and the bottom circular surface are coaxial; S23. Generate a smooth transition curve that passes through the edges of the top circular surface, the middle reference circular surface and the bottom circular surface simultaneously as a generatrix. Rotate the generatrix around an axis that passes through the middle reference circular surface, the top circular surface and the bottom circular surface coaxially to form a smooth transition surface. S24. Fill the opening end faces corresponding to the top and bottom circular surfaces to obtain a closed three-dimensional solid model; S3. Based on the center wavelength and the preset geometric ratio, determine the values ​​of the diameter and structural height of the middle reference circle, the top circle, and the bottom circle; S4. Based on the three-dimensional solid model constructed in step S2 and the values ​​determined in S3, establish a three-dimensional electromagnetic simulation model of the three-dimensional solid model and perform scattering performance simulation. Iteratively optimize the values ​​according to the simulation results until the preset performance indicators are met.

7. The design method as described in claim 6, characterized in that, The preset geometric proportions include: The ratio of the top circular surface diameter to the bottom circular surface diameter to the middle reference circular surface diameter ranges from 1 / 3 to 1 / 5; The ratio of the structure height to the diameter of the intermediate reference circle ranges from 1 / 6 to 1 / 10.

8. The design method as described in claim 6, characterized in that, The diameter of the intermediate reference circle is associated with the center wavelength of the target radar threat band.

9. The design method as described in claim 8, characterized in that, The diameter D of the intermediate reference circle mid The frequency band of the target radar threat band is a multiple of the center wavelength λ: D mid =mλ, where m is the multiplier.

10. The design method as described in claim 6, characterized in that, In step S4, the scattering performance simulation includes: setting a vertically polarized plane wave to be incident normally along the central axis of the carrier, and analyzing the radar cross section values ​​and curve fluctuation characteristics within the target threat frequency band within the azimuth angle ±30° for iterative optimization of the values ​​for the target.

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